in the presence of multibyte characters
- bash_vi_complete: call vi_advance_point instead of just incrementing
rl_point
+
+ 2/5
+ ---
+doc/bash.1,lib/readline/doc/readline.3
+ - minor updates to handle old versions of troff and groff warnings
+ Fixes from G. Branden Robinson <g.branden.robinson@gmail.com>
-BASH(1) General Commands Manual BASH(1)
-
-
+_\bB_\bA_\bS_\bH(1) General Commands Manual _\bB_\bA_\bS_\bH(1)
N\bNA\bAM\bME\bE
bash - GNU Bourne-Again SHell
commands read from the standard input or from a file. B\bBa\bas\bsh\bh also incor-
porates useful features from the _\bK_\bo_\br_\bn and _\bC shells (k\bks\bsh\bh and c\bcs\bsh\bh).
- B\bBa\bas\bsh\bh is intended to be a conformant implementation of the Shell and
- Utilities portion of the IEEE POSIX specification (IEEE Standard
+ B\bBa\bas\bsh\bh is intended to be a conformant implementation of the Shell and
+ Utilities portion of the IEEE POSIX specification (IEEE Standard
1003.1). B\bBa\bas\bsh\bh can be configured to be POSIX-conformant by default.
O\bOP\bPT\bTI\bIO\bON\bNS\bS
-\b-c\bc If the -\b-c\bc option is present, then commands are read from the
first non-option argument _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bs_\bt_\br_\bi_\bn_\bg. If there are argu-
- ments after the _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bs_\bt_\br_\bi_\bn_\bg, the first argument is as-
- signed to $\b$0\b0 and any remaining arguments are assigned to the
+ ments after the _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bs_\bt_\br_\bi_\bn_\bg, the first argument is as-
+ signed to $\b$0\b0 and any remaining arguments are assigned to the
positional parameters. The assignment to $\b$0\b0 sets the name of
the shell, which is used in warning and error messages.
-\b-i\bi If the -\b-i\bi option is present, the shell is _\bi_\bn_\bt_\be_\br_\ba_\bc_\bt_\bi_\bv_\be.
-\b-l\bl Make b\bba\bas\bsh\bh act as if it had been invoked as a login shell (see
I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN below).
- -\b-r\br If the -\b-r\br option is present, the shell becomes _\br_\be_\bs_\bt_\br_\bi_\bc_\bt_\be_\bd
+ -\b-r\br If the -\b-r\br option is present, the shell becomes _\br_\be_\bs_\bt_\br_\bi_\bc_\bt_\be_\bd
(see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL below).
- -\b-s\bs If the -\b-s\bs option is present, or if no arguments remain after
- option processing, then commands are read from the standard
- input. This option allows the positional parameters to be
- set when invoking an interactive shell or when reading input
+ -\b-s\bs If the -\b-s\bs option is present, or if no arguments remain after
+ option processing, then commands are read from the standard
+ input. This option allows the positional parameters to be
+ set when invoking an interactive shell or when reading input
through a pipe.
- -\b-D\bD A list of all double-quoted strings preceded by $\b$ is printed
- on the standard output. These are the strings that are sub-
+ -\b-D\bD A list of all double-quoted strings preceded by $\b$ is printed
+ on the standard output. These are the strings that are sub-
ject to language translation when the current locale is not C\bC
or P\bPO\bOS\bSI\bIX\bX. This implies the -\b-n\bn option; no commands will be
executed.
_\bs_\bh_\bo_\bp_\bt_\b__\bo_\bp_\bt_\bi_\bo_\bn is one of the shell options accepted by the
s\bsh\bho\bop\bpt\bt builtin (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below). If
_\bs_\bh_\bo_\bp_\bt_\b__\bo_\bp_\bt_\bi_\bo_\bn is present, -\b-O\bO sets the value of that option; +\b+O\bO
- unsets it. If _\bs_\bh_\bo_\bp_\bt_\b__\bo_\bp_\bt_\bi_\bo_\bn is not supplied, the names and
- values of the shell options accepted by s\bsh\bho\bop\bpt\bt are printed on
- the standard output. If the invocation option is +\b+O\bO, the
+ unsets it. If _\bs_\bh_\bo_\bp_\bt_\b__\bo_\bp_\bt_\bi_\bo_\bn is not supplied, the names and
+ values of the shell options accepted by s\bsh\bho\bop\bpt\bt are printed on
+ the standard output. If the invocation option is +\b+O\bO, the
output is displayed in a format that may be reused as input.
- -\b--\b- A -\b--\b- signals the end of options and disables further option
- processing. Any arguments after the -\b--\b- are treated as a
- shell script filename (see below) and arguments passed to
+ -\b--\b- A -\b--\b- signals the end of options and disables further option
+ processing. Any arguments after the -\b--\b- are treated as a
+ shell script filename (see below) and arguments passed to
that script. An argument of -\b- is equivalent to -\b--\b-.
- B\bBa\bas\bsh\bh also interprets a number of multi-character options. These op-
- tions must appear on the command line before the single-character op-
+ B\bBa\bas\bsh\bh also interprets a number of multi-character options. These op-
+ tions must appear on the command line before the single-character op-
tions to be recognized.
-\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br
starts. Turns on extended debugging mode (see the description
of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin below).
-\b--\b-d\bdu\bum\bmp\bp-\b-p\bpo\bo-\b-s\bst\btr\bri\bin\bng\bgs\bs
- Equivalent to -\b-D\bD, but the output is in the GNU _\bg_\be_\bt_\bt_\be_\bx_\bt p\bpo\bo (por-
- table object) file format.
+ Equivalent to -\b-D\bD, but the output is in the GNU _\bg_\be_\bt_\bt_\be_\bx_\bt p\bpo\bo
+ (portable object) file format.
-\b--\b-d\bdu\bum\bmp\bp-\b-s\bst\btr\bri\bin\bng\bgs\bs
Equivalent to -\b-D\bD.
-\b--\b-h\bhe\bel\blp\bp Display a usage message on standard output and exit success-
-\b--\b-i\bin\bni\bit\bt-\b-f\bfi\bil\ble\be _\bf_\bi_\bl_\be
-\b--\b-r\brc\bcf\bfi\bil\ble\be _\bf_\bi_\bl_\be
Execute commands from _\bf_\bi_\bl_\be instead of the standard personal ini-
- tialization file _\b~_\b/_\b._\bb_\ba_\bs_\bh_\br_\bc if the shell is interactive (see I\bIN\bN-\b-
+ tialization file _\b~_\b/_\b._\bb_\ba_\bs_\bh_\br_\bc if the shell is interactive (see I\bIN\bN-\b-
V\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN below).
-\b--\b-l\blo\bog\bgi\bin\bn
Equivalent to -\b-l\bl.
-\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg
- Do not use the GNU r\bre\bea\bad\bdl\bli\bin\bne\be library to read command lines when
+ Do not use the GNU r\bre\bea\bad\bdl\bli\bin\bne\be library to read command lines when
the shell is interactive.
-\b--\b-n\bno\bop\bpr\bro\bof\bfi\bil\ble\be
- Do not read either the system-wide startup file _\b/_\be_\bt_\bc_\b/_\bp_\br_\bo_\bf_\bi_\bl_\be or
- any of the personal initialization files _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bp_\br_\bo_\bf_\bi_\bl_\be,
- _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bl_\bo_\bg_\bi_\bn, or _\b~_\b/_\b._\bp_\br_\bo_\bf_\bi_\bl_\be. By default, b\bba\bas\bsh\bh reads these
- files when it is invoked as a login shell (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN be-
+ Do not read either the system-wide startup file _\b/_\be_\bt_\bc_\b/_\bp_\br_\bo_\bf_\bi_\bl_\be or
+ any of the personal initialization files _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bp_\br_\bo_\bf_\bi_\bl_\be,
+ _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bl_\bo_\bg_\bi_\bn, or _\b~_\b/_\b._\bp_\br_\bo_\bf_\bi_\bl_\be. By default, b\bba\bas\bsh\bh reads these
+ files when it is invoked as a login shell (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN be-
low).
-\b--\b-n\bno\bor\brc\bc Do not read and execute the personal initialization file
-\b--\b-p\bpo\bos\bsi\bix\bx
Change the behavior of b\bba\bas\bsh\bh where the default operation differs
from the POSIX standard to match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be). See
- S\bSE\bEE\bE A\bAL\bLS\bSO\bO below for a reference to a document that details how
+ S\bSE\bEE\bE A\bAL\bLS\bSO\bO below for a reference to a document that details how
posix mode affects bash's behavior.
-\b--\b-r\bre\bes\bst\btr\bri\bic\bct\bte\bed\bd
Equivalent to -\b-v\bv.
-\b--\b-v\bve\ber\brs\bsi\bio\bon\bn
- Show version information for this instance of b\bba\bas\bsh\bh on the stan-
+ Show version information for this instance of b\bba\bas\bsh\bh on the stan-
dard output and exit successfully.
A\bAR\bRG\bGU\bUM\bME\bEN\bNT\bTS\bS
sitional parameters are set to the remaining arguments. B\bBa\bas\bsh\bh reads and
executes commands from this file, then exits. B\bBa\bas\bsh\bh's exit status is
the exit status of the last command executed in the script. If no com-
- mands are executed, the exit status is 0. An attempt is first made to
- open the file in the current directory, and, if no file is found, then
+ mands are executed, the exit status is 0. An attempt is first made to
+ open the file in the current directory, and, if no file is found, then
the shell searches the directories in P\bPA\bAT\bTH\bH for the script.
I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN
- A _\bl_\bo_\bg_\bi_\bn _\bs_\bh_\be_\bl_\bl is one whose first character of argument zero is a -\b-, or
+ A _\bl_\bo_\bg_\bi_\bn _\bs_\bh_\be_\bl_\bl is one whose first character of argument zero is a -\b-, or
one started with the -\b--\b-l\blo\bog\bgi\bin\bn option.
- An _\bi_\bn_\bt_\be_\br_\ba_\bc_\bt_\bi_\bv_\be shell is one started without non-option arguments (un-
- less -\b-s\bs is specified) and without the -\b-c\bc option, whose standard input
+ An _\bi_\bn_\bt_\be_\br_\ba_\bc_\bt_\bi_\bv_\be shell is one started without non-option arguments (un-
+ less -\b-s\bs is specified) and without the -\b-c\bc option, whose standard input
and error are both connected to terminals (as determined by _\bi_\bs_\ba_\bt_\bt_\by(3)),
or one started with the -\b-i\bi option. P\bPS\bS1\b1 is set and $\b$-\b- includes i\bi if
b\bba\bas\bsh\bh is interactive, allowing a shell script or a startup file to test
active shell with the -\b--\b-l\blo\bog\bgi\bin\bn option, it first reads and executes com-
mands from the file _\b/_\be_\bt_\bc_\b/_\bp_\br_\bo_\bf_\bi_\bl_\be, if that file exists. After reading
that file, it looks for _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bp_\br_\bo_\bf_\bi_\bl_\be, _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bl_\bo_\bg_\bi_\bn, and _\b~_\b/_\b._\bp_\br_\bo_\bf_\bi_\bl_\be,
- in that order, and reads and executes commands from the first one that
- exists and is readable. The -\b--\b-n\bno\bop\bpr\bro\bof\bfi\bil\ble\be option may be used when the
+ in that order, and reads and executes commands from the first one that
+ exists and is readable. The -\b--\b-n\bno\bop\bpr\bro\bof\bfi\bil\ble\be option may be used when the
shell is started to inhibit this behavior.
When an interactive login shell exits, or a non-interactive login shell
its value if it appears there, and uses the expanded value as the name
of a file to read and execute. B\bBa\bas\bsh\bh behaves as if the following com-
mand were executed:
+
if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
+
but the value of the P\bPA\bAT\bTH\bH variable is not used to search for the file-
name.
name s\bsh\bh, b\bba\bas\bsh\bh looks for the variable E\bEN\bNV\bV, expands its value if it is
defined, and uses the expanded value as the name of a file to read and
execute. Since a shell invoked as s\bsh\bh does not attempt to read and exe-
- cute commands from any other startup files, the -\b--\b-r\brc\bcf\bfi\bil\ble\be option has no
- effect. A non-interactive shell invoked with the name s\bsh\bh does not at-
+ cute commands from any other startup files, the -\b--\b-r\brc\bcf\bfi\bil\ble\be option has no
+ effect. A non-interactive shell invoked with the name s\bsh\bh does not at-
tempt to read any other startup files. When invoked as s\bsh\bh, b\bba\bas\bsh\bh enters
_\bp_\bo_\bs_\bi_\bx mode after the startup files are read.
When b\bba\bas\bsh\bh is started in _\bp_\bo_\bs_\bi_\bx mode, as with the -\b--\b-p\bpo\bos\bsi\bix\bx command line
option, it follows the POSIX standard for startup files. In this mode,
- interactive shells expand the E\bEN\bNV\bV variable and commands are read and
- executed from the file whose name is the expanded value. No other
+ interactive shells expand the E\bEN\bNV\bV variable and commands are read and
+ executed from the file whose name is the expanded value. No other
startup files are read.
B\bBa\bas\bsh\bh attempts to determine when it is being run with its standard input
connected to a network connection, as when executed by the historical
remote shell daemon, usually _\br_\bs_\bh_\bd, or the secure shell daemon _\bs_\bs_\bh_\bd. If
- b\bba\bas\bsh\bh determines it is being run non-interactively in this fashion, it
- reads and executes commands from _\b~_\b/_\b._\bb_\ba_\bs_\bh_\br_\bc, if that file exists and is
+ b\bba\bas\bsh\bh determines it is being run non-interactively in this fashion, it
+ reads and executes commands from _\b~_\b/_\b._\bb_\ba_\bs_\bh_\br_\bc, if that file exists and is
readable. It will not do this if invoked as s\bsh\bh. The -\b--\b-n\bno\bor\brc\bc option may
be used to inhibit this behavior, and the -\b--\b-r\brc\bcf\bfi\bil\ble\be option may be used
to force another file to be read, but neither _\br_\bs_\bh_\bd nor _\bs_\bs_\bh_\bd generally
If the shell is started with the effective user (group) id not equal to
the real user (group) id, and the -\b-p\bp option is not supplied, no startup
files are read, shell functions are not inherited from the environment,
- the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS, B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
- pear in the environment, are ignored, and the effective user id is set
- to the real user id. If the -\b-p\bp option is supplied at invocation, the
+ the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS, B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
+ pear in the environment, are ignored, and the effective user id is set
+ to the real user id. If the -\b-p\bp option is supplied at invocation, the
startup behavior is the same, but the effective user id is not reset.
D\bDE\bEF\bFI\bIN\bNI\bIT\bTI\bIO\bON\bNS\bS
- The following definitions are used throughout the rest of this docu-
+ The following definitions are used throughout the rest of this docu-
ment.
b\bbl\bla\ban\bnk\bk A space or tab.
- w\bwo\bor\brd\bd A sequence of characters considered as a single unit by the
+ w\bwo\bor\brd\bd A sequence of characters considered as a single unit by the
shell. Also known as a t\bto\bok\bke\ben\bn.
- n\bna\bam\bme\be A _\bw_\bo_\br_\bd consisting only of alphanumeric characters and under-
- scores, and beginning with an alphabetic character or an under-
+ n\bna\bam\bme\be A _\bw_\bo_\br_\bd consisting only of alphanumeric characters and under-
+ scores, and beginning with an alphabetic character or an under-
score. Also referred to as an i\bid\bde\ben\bnt\bti\bif\bfi\bie\ber\br.
m\bme\bet\bta\bac\bch\bha\bar\bra\bac\bct\bte\ber\br
- A character that, when unquoted, separates words. One of the
+ A character that, when unquoted, separates words. One of the
following:
|\b| &\b& ;\b; (\b( )\b) <\b< >\b> s\bsp\bpa\bac\bce\be t\bta\bab\bb n\bne\bew\bwl\bli\bin\bne\be
c\bco\bon\bnt\btr\bro\bol\bl o\bop\bpe\ber\bra\bat\bto\bor\br
A _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd is a sequence of optional variable assignments fol-
lowed by b\bbl\bla\ban\bnk\bk-separated words and redirections, and terminated by a
_\bc_\bo_\bn_\bt_\br_\bo_\bl _\bo_\bp_\be_\br_\ba_\bt_\bo_\br. The first word specifies the command to be executed,
- and is passed as argument zero. The remaining words are passed as ar-
+ and is passed as argument zero. The remaining words are passed as ar-
guments to the invoked command.
- The return value of a _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd is its exit status, or 128+_\bn if
+ The return value of a _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd is its exit status, or 128+_\bn if
the command is terminated by signal _\bn.
P\bPi\bip\bpe\bel\bli\bin\bne\bes\bs
- A _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be is a sequence of one or more commands separated by one of
+ A _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be is a sequence of one or more commands separated by one of
the control operators |\b| or |\b|&\b&. The format for a pipeline is:
[t\bti\bim\bme\be [-\b-p\bp]] [ ! ] _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 [ [|\b|||\b|&\b&] _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2 ... ]
The standard output of _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 is connected via a pipe to the standard
input of _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2. This connection is performed before any redirec-
tions specified by the _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1(see R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN below). If |\b|&\b& is used,
- _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1's standard error, in addition to its standard output, is con-
- nected to _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2's standard input through the pipe; it is shorthand
- for 2\b2>\b>&\b&1\b1 |\b|. This implicit redirection of the standard error to the
- standard output is performed after any redirections specified by _\bc_\bo_\bm_\b-
+ _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1's standard error, in addition to its standard output, is con-
+ nected to _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2's standard input through the pipe; it is shorthand
+ for 2\b2>\b>&\b&1\b1 |\b|. This implicit redirection of the standard error to the
+ standard output is performed after any redirections specified by _\bc_\bo_\bm_\b-
_\bm_\ba_\bn_\bd_\b1.
The return status of a pipeline is the exit status of the last command,
pipeline's return status is the value of the last (rightmost) command
to exit with a non-zero status, or zero if all commands exit success-
fully. If the reserved word !\b! precedes a pipeline, the exit status of
- that pipeline is the logical negation of the exit status as described
- above. The shell waits for all commands in the pipeline to terminate
+ that pipeline is the logical negation of the exit status as described
+ above. The shell waits for all commands in the pipeline to terminate
before returning a value.
- If the t\bti\bim\bme\be reserved word precedes a pipeline, the elapsed as well as
- user and system time consumed by its execution are reported when the
- pipeline terminates. The -\b-p\bp option changes the output format to that
- specified by POSIX. When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it does not rec-
- ognize t\bti\bim\bme\be as a reserved word if the next token begins with a `-'.
- The T\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable may be set to a format string that specifies
- how the timing information should be displayed; see the description of
+ If the t\bti\bim\bme\be reserved word precedes a pipeline, the elapsed as well as
+ user and system time consumed by its execution are reported when the
+ pipeline terminates. The -\b-p\bp option changes the output format to that
+ specified by POSIX. When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it does not rec-
+ ognize t\bti\bim\bme\be as a reserved word if the next token begins with a "-".
+ The T\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable may be set to a format string that specifies
+ how the timing information should be displayed; see the description of
T\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT under S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs below.
When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, t\bti\bim\bme\be may be followed by a newline. In
wait for the command to finish, and the return status is 0. These are
referred to as _\ba_\bs_\by_\bn_\bc_\bh_\br_\bo_\bn_\bo_\bu_\bs commands. Commands separated by a ;\b; are
executed sequentially; the shell waits for each command to terminate in
- turn. The return status is the exit status of the last command exe-
+ turn. The return status is the exit status of the last command exe-
cuted.
- AND and OR lists are sequences of one or more pipelines separated by
- the &\b&&\b& and |\b||\b| control operators, respectively. AND and OR lists are
+ AND and OR lists are sequences of one or more pipelines separated by
+ the &\b&&\b& and |\b||\b| control operators, respectively. AND and OR lists are
executed with left associativity. An AND list has the form
_\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 &\b&&\b& _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2
- _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2 is executed if, and only if, _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 returns an exit status
+ _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2 is executed if, and only if, _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 returns an exit status
of zero (success).
An OR list has the form
_\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 |\b||\b| _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2
- _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2 is executed if, and only if, _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 returns a non-zero exit
- status. The return status of AND and OR lists is the exit status of
+ _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b2 is executed if, and only if, _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b1 returns a non-zero exit
+ status. The return status of AND and OR lists is the exit status of
the last command executed in the list.
C\bCo\bom\bmp\bpo\bou\bun\bnd\bd C\bCo\bom\bmm\bma\ban\bnd\bds\bs
- A _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd _\bc_\bo_\bm_\bm_\ba_\bn_\bd is one of the following. In most cases a _\bl_\bi_\bs_\bt in a
- command's description may be separated from the rest of the command by
- one or more newlines, and may be followed by a newline in place of a
+ A _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd _\bc_\bo_\bm_\bm_\ba_\bn_\bd is one of the following. In most cases a _\bl_\bi_\bs_\bt in a
+ command's description may be separated from the rest of the command by
+ one or more newlines, and may be followed by a newline in place of a
semicolon.
- (_\bl_\bi_\bs_\bt) _\bl_\bi_\bs_\bt is executed in a subshell (see C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bN-\b-
- M\bME\bEN\bNT\bT below for a description of a subshell environment). Vari-
- able assignments and builtin commands that affect the shell's
+ (_\bl_\bi_\bs_\bt) _\bl_\bi_\bs_\bt is executed in a subshell (see C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bN-\b-
+ M\bME\bEN\bNT\bT below for a description of a subshell environment). Vari-
+ able assignments and builtin commands that affect the shell's
environment do not remain in effect after the command completes.
The return status is the exit status of _\bl_\bi_\bs_\bt.
as a _\bg_\br_\bo_\bu_\bp _\bc_\bo_\bm_\bm_\ba_\bn_\bd. The return status is the exit status of
_\bl_\bi_\bs_\bt. Note that unlike the metacharacters (\b( and )\b), {\b{ and }\b} are
_\br_\be_\bs_\be_\br_\bv_\be_\bd _\bw_\bo_\br_\bd_\bs and must occur where a reserved word is permitted
- to be recognized. Since they do not cause a word break, they
- must be separated from _\bl_\bi_\bs_\bt by whitespace or another shell
+ to be recognized. Since they do not cause a word break, they
+ must be separated from _\bl_\bi_\bs_\bt by whitespace or another shell
metacharacter.
((_\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn))
the primaries described below under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS.
The words between the [\b[[\b[ and ]\b]]\b] do not undergo word splitting
and pathname expansion. The shell performs tilde expansion, pa-
- rameter and variable expansion, arithmetic expansion, command
- substitution, process substitution, and quote removal on those
- words (the expansions that would occur if the words were en-
+ rameter and variable expansion, arithmetic expansion, command
+ substitution, process substitution, and quote removal on those
+ words (the expansions that would occur if the words were en-
closed in double quotes). Conditional operators such as -\b-f\bf must
be unquoted to be recognized as primaries.
of the operator is considered a pattern and matched according to
the rules described below under P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg, as if the e\bex\bxt\bt-\b-
g\bgl\blo\bob\bb shell option were enabled. The =\b= operator is equivalent to
- =\b==\b=. If the n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh shell option is enabled, the match is
- performed without regard to the case of alphabetic characters.
- The return value is 0 if the string matches (=\b==\b=) or does not
- match (!\b!=\b=) the pattern, and 1 otherwise. Any part of the pat-
- tern may be quoted to force the quoted portion to be matched as
+ =\b==\b=. If the n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh shell option is enabled, the match is
+ performed without regard to the case of alphabetic characters.
+ The return value is 0 if the string matches (=\b==\b=) or does not
+ match (!\b!=\b=) the pattern, and 1 otherwise. Any part of the pat-
+ tern may be quoted to force the quoted portion to be matched as
a string.
- An additional binary operator, =\b=~\b~, is available, with the same
- precedence as =\b==\b= and !\b!=\b=. When it is used, the string to the
+ An additional binary operator, =\b=~\b~, is available, with the same
+ precedence as =\b==\b= and !\b!=\b=. When it is used, the string to the
right of the operator is considered a POSIX extended regular ex-
pression and matched accordingly (using the POSIX _\br_\be_\bg_\bc_\bo_\bm_\bp and
_\br_\be_\bg_\be_\bx_\be_\bc interfaces usually described in _\br_\be_\bg_\be_\bx(3)). The return
tional expression's return value is 2. If the n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh shell
option is enabled, the match is performed without regard to the
case of alphabetic characters. If any part of the pattern is
- quoted, the quoted portion is matched literally. This means ev-
- ery character in the quoted portion matches itself, instead of
- having any special pattern matching meaning. If the pattern is
- stored in a shell variable, quoting the variable expansion
- forces the entire pattern to be matched literally. Treat
+ quoted, the quoted portion is matched literally. This means
+ every character in the quoted portion matches itself, instead of
+ having any special pattern matching meaning. If the pattern is
+ stored in a shell variable, quoting the variable expansion
+ forces the entire pattern to be matched literally. Treat
bracket expressions in regular expressions carefully, since nor-
mal quoting and pattern characters lose their meanings between
brackets.
The pattern will match if it matches any part of the string.
Anchor the pattern using the ^\b^ and $\b$ regular expression opera-
tors to force it to match the entire string. The array variable
- B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH records which parts of the string matched the pat-
- tern. The element of B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH with index 0 contains the
- portion of the string matching the entire regular expression.
- Substrings matched by parenthesized subexpressions within the
- regular expression are saved in the remaining B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH in-
- dices. The element of B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH with index _\bn is the portion
- of the string matching the _\bnth parenthesized subexpression.
- B\bBa\bas\bsh\bh sets B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH in the global scope; declaring it as a
+ B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH records which parts of the string matched the pat-
+ tern. The element of B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH with index 0 contains the
+ portion of the string matching the entire regular expression.
+ Substrings matched by parenthesized subexpressions within the
+ regular expression are saved in the remaining B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH in-
+ dices. The element of B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH with index _\bn is the portion
+ of the string matching the _\bnth parenthesized subexpression.
+ B\bBa\bas\bsh\bh sets B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH in the global scope; declaring it as a
local variable will lead to unexpected results.
- Expressions may be combined using the following operators,
+ Expressions may be combined using the following operators,
listed in decreasing order of precedence:
(\b( _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn )\b)
- Returns the value of _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn. This may be used to
+ Returns the value of _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn. This may be used to
override the normal precedence of operators.
!\b! _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn
True if _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn is false.
s\bse\bel\ble\bec\bct\bt _\bn_\ba_\bm_\be [ i\bin\bn _\bw_\bo_\br_\bd ] ; d\bdo\bo _\bl_\bi_\bs_\bt ; d\bdo\bon\bne\be
The list of words following i\bin\bn is expanded, generating a list of
- items, and the set of expanded words is printed on the standard
- error, each preceded by a number. If the i\bin\bn _\bw_\bo_\br_\bd is omitted,
- the positional parameters are printed (see P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS below).
- s\bse\bel\ble\bec\bct\bt then displays the P\bPS\bS3\b3 prompt and reads a line from the
- standard input. If the line consists of a number corresponding
- to one of the displayed words, then the value of _\bn_\ba_\bm_\be is set to
- that word. If the line is empty, the words and prompt are dis-
- played again. If EOF is read, the s\bse\bel\ble\bec\bct\bt command completes and
- returns 1. Any other value read causes _\bn_\ba_\bm_\be to be set to null.
- The line read is saved in the variable R\bRE\bEP\bPL\bLY\bY. The _\bl_\bi_\bs_\bt is exe-
- cuted after each selection until a b\bbr\bre\bea\bak\bk command is executed.
+ items, and the set of expanded words is printed on the standard
+ error, each preceded by a number. If the i\bin\bn _\bw_\bo_\br_\bd is omitted,
+ the positional parameters are printed (see P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS below).
+ s\bse\bel\ble\bec\bct\bt then displays the P\bPS\bS3\b3 prompt and reads a line from the
+ standard input. If the line consists of a number corresponding
+ to one of the displayed words, then the value of _\bn_\ba_\bm_\be is set to
+ that word. If the line is empty, the words and prompt are dis-
+ played again. If EOF is read, the s\bse\bel\ble\bec\bct\bt command completes and
+ returns 1. Any other value read causes _\bn_\ba_\bm_\be to be set to null.
+ The line read is saved in the variable R\bRE\bEP\bPL\bLY\bY. The _\bl_\bi_\bs_\bt is exe-
+ cuted after each selection until a b\bbr\bre\bea\bak\bk command is executed.
The exit status of s\bse\bel\ble\bec\bct\bt is the exit status of the last command
executed in _\bl_\bi_\bs_\bt, or zero if no commands were executed.
c\bca\bas\bse\be _\bw_\bo_\br_\bd i\bin\bn [ [(] _\bp_\ba_\bt_\bt_\be_\br_\bn [ |\b| _\bp_\ba_\bt_\bt_\be_\br_\bn ] ... ) _\bl_\bi_\bs_\bt ;; ] ... e\bes\bsa\bac\bc
A c\bca\bas\bse\be command first expands _\bw_\bo_\br_\bd, and tries to match it against
- each _\bp_\ba_\bt_\bt_\be_\br_\bn in turn, using the matching rules described under
+ each _\bp_\ba_\bt_\bt_\be_\br_\bn in turn, using the matching rules described under
P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below. The _\bw_\bo_\br_\bd is expanded using tilde expan-
sion, parameter and variable expansion, arithmetic expansion,
command substitution, process substitution and quote removal.
Each _\bp_\ba_\bt_\bt_\be_\br_\bn examined is expanded using tilde expansion, parame-
- ter and variable expansion, arithmetic expansion, command sub-
- stitution, process substitution, and quote removal. If the n\bno\bo-\b-
- c\bca\bas\bse\bem\bma\bat\btc\bch\bh shell option is enabled, the match is performed with-
- out regard to the case of alphabetic characters. When a match
- is found, the corresponding _\bl_\bi_\bs_\bt is executed. If the ;\b;;\b; opera-
+ ter and variable expansion, arithmetic expansion, command sub-
+ stitution, process substitution, and quote removal. If the n\bno\bo-\b-
+ c\bca\bas\bse\bem\bma\bat\btc\bch\bh shell option is enabled, the match is performed with-
+ out regard to the case of alphabetic characters. When a match
+ is found, the corresponding _\bl_\bi_\bs_\bt is executed. If the ;\b;;\b; opera-
tor is used, no subsequent matches are attempted after the first
pattern match. Using ;\b;&\b& in place of ;\b;;\b; causes execution to con-
- tinue with the _\bl_\bi_\bs_\bt associated with the next set of patterns.
- Using ;\b;;\b;&\b& in place of ;\b;;\b; causes the shell to test the next pat-
- tern list in the statement, if any, and execute any associated
+ tinue with the _\bl_\bi_\bs_\bt associated with the next set of patterns.
+ Using ;\b;;\b;&\b& in place of ;\b;;\b; causes the shell to test the next pat-
+ tern list in the statement, if any, and execute any associated
_\bl_\bi_\bs_\bt on a successful match, continuing the case statement execu-
tion as if the pattern list had not matched. The exit status is
zero if no pattern matches. Otherwise, it is the exit status of
_\bl_\bi_\bs_\bt is executed. Otherwise, each e\bel\bli\bif\bf _\bl_\bi_\bs_\bt is executed in
turn, and if its exit status is zero, the corresponding t\bth\bhe\ben\bn
_\bl_\bi_\bs_\bt is executed and the command completes. Otherwise, the e\bel\bls\bse\be
- _\bl_\bi_\bs_\bt is executed, if present. The exit status is the exit sta-
+ _\bl_\bi_\bs_\bt is executed, if present. The exit status is the exit sta-
tus of the last command executed, or zero if no condition tested
true.
u\bun\bnt\bti\bil\bl _\bl_\bi_\bs_\bt_\b-_\b1; d\bdo\bo _\bl_\bi_\bs_\bt_\b-_\b2; d\bdo\bon\bne\be
The w\bwh\bhi\bil\ble\be command continuously executes the list _\bl_\bi_\bs_\bt_\b-_\b2 as long
as the last command in the list _\bl_\bi_\bs_\bt_\b-_\b1 returns an exit status of
- zero. The u\bun\bnt\bti\bil\bl command is identical to the w\bwh\bhi\bil\ble\be command, ex-
+ zero. The u\bun\bnt\bti\bil\bl command is identical to the w\bwh\bhi\bil\ble\be command, ex-
cept that the test is negated: _\bl_\bi_\bs_\bt_\b-_\b2 is executed as long as the
last command in _\bl_\bi_\bs_\bt_\b-_\b1 returns a non-zero exit status. The exit
status of the w\bwh\bhi\bil\ble\be and u\bun\bnt\bti\bil\bl commands is the exit status of the
C\bCo\bop\bpr\bro\boc\bce\bes\bss\bse\bes\bs
A _\bc_\bo_\bp_\br_\bo_\bc_\be_\bs_\bs is a shell command preceded by the c\bco\bop\bpr\bro\boc\bc reserved word. A
- coprocess is executed asynchronously in a subshell, as if the command
- had been terminated with the &\b& control operator, with a two-way pipe
+ coprocess is executed asynchronously in a subshell, as if the command
+ had been terminated with the &\b& control operator, with a two-way pipe
established between the executing shell and the coprocess.
The syntax for a coprocess is:
c\bco\bop\bpr\bro\boc\bc [_\bN_\bA_\bM_\bE] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\br_\be_\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn_\bs]
- This creates a coprocess named _\bN_\bA_\bM_\bE. _\bc_\bo_\bm_\bm_\ba_\bn_\bd may be either a simple
- command or a compound command (see above). _\bN_\bA_\bM_\bE is a shell variable
+ This creates a coprocess named _\bN_\bA_\bM_\bE. _\bc_\bo_\bm_\bm_\ba_\bn_\bd may be either a simple
+ command or a compound command (see above). _\bN_\bA_\bM_\bE is a shell variable
name. If _\bN_\bA_\bM_\bE is not supplied, the default name is C\bCO\bOP\bPR\bRO\bOC\bC.
The recommended form to use for a coprocess is
c\bco\bop\bpr\bro\boc\bc _\bN_\bA_\bM_\bE { _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\br_\be_\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn_\bs]; }
- This form is recommended because simple commands result in the copro-
- cess always being named C\bCO\bOP\bPR\bRO\bOC\bC, and it is simpler to use and more com-
- plete than the other compound commands.
+ This form is recommended because simple commands result in the co-
+ process always being named C\bCO\bOP\bPR\bRO\bOC\bC, and it is simpler to use and more
+ complete than the other compound commands.
- If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is a compound command, _\bN_\bA_\bM_\bE is optional. The word following
- c\bco\bop\bpr\bro\boc\bc determines whether that word is interpreted as a variable name:
- it is interpreted as _\bN_\bA_\bM_\bE if it is not a reserved word that introduces
- a compound command. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is a simple command, _\bN_\bA_\bM_\bE is not al-
- lowed; this is to avoid confusion between _\bN_\bA_\bM_\bE and the first word of
+ If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is a compound command, _\bN_\bA_\bM_\bE is optional. The word following
+ c\bco\bop\bpr\bro\boc\bc determines whether that word is interpreted as a variable name:
+ it is interpreted as _\bN_\bA_\bM_\bE if it is not a reserved word that introduces
+ a compound command. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is a simple command, _\bN_\bA_\bM_\bE is not al-
+ lowed; this is to avoid confusion between _\bN_\bA_\bM_\bE and the first word of
the simple command.
- When the coprocess is executed, the shell creates an array variable
- (see A\bAr\brr\bra\bay\bys\bs below) named _\bN_\bA_\bM_\bE in the context of the executing shell.
- The standard output of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is connected via a pipe to a file de-
- scriptor in the executing shell, and that file descriptor is assigned
+ When the coprocess is executed, the shell creates an array variable
+ (see A\bAr\brr\bra\bay\bys\bs below) named _\bN_\bA_\bM_\bE in the context of the executing shell.
+ The standard output of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is connected via a pipe to a file de-
+ scriptor in the executing shell, and that file descriptor is assigned
to _\bN_\bA_\bM_\bE[0]. The standard input of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is connected via a pipe to a
file descriptor in the executing shell, and that file descriptor is as-
- signed to _\bN_\bA_\bM_\bE[1]. This pipe is established before any redirections
+ signed to _\bN_\bA_\bM_\bE[1]. This pipe is established before any redirections
specified by the command (see R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN below). The file descriptors
can be utilized as arguments to shell commands and redirections using
standard word expansions. Other than those created to execute command
_\bf_\bn_\ba_\bm_\be () _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\br_\be_\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn]
f\bfu\bun\bnc\bct\bti\bio\bon\bn _\bf_\bn_\ba_\bm_\be [()] _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\br_\be_\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn]
This defines a function named _\bf_\bn_\ba_\bm_\be. The reserved word f\bfu\bun\bnc\bct\bti\bio\bon\bn
- is optional. If the f\bfu\bun\bnc\bct\bti\bio\bon\bn reserved word is supplied, the
- parentheses are optional. The _\bb_\bo_\bd_\by of the function is the com-
- pound command _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd (see C\bCo\bom\bmp\bpo\bou\bun\bnd\bd C\bCo\bom\bmm\bma\ban\bnd\bds\bs above).
- That command is usually a _\bl_\bi_\bs_\bt of commands between { and }, but
+ is optional. If the f\bfu\bun\bnc\bct\bti\bio\bon\bn reserved word is supplied, the
+ parentheses are optional. The _\bb_\bo_\bd_\by of the function is the com-
+ pound command _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd (see C\bCo\bom\bmp\bpo\bou\bun\bnd\bd C\bCo\bom\bmm\bma\ban\bnd\bds\bs above).
+ That command is usually a _\bl_\bi_\bs_\bt of commands between { and }, but
may be any command listed under C\bCo\bom\bmp\bpo\bou\bun\bnd\bd C\bCo\bom\bmm\bma\ban\bnd\bds\bs above. If the
f\bfu\bun\bnc\bct\bti\bio\bon\bn reserved word is used, but the parentheses are not sup-
plied, the braces are recommended. _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed
whenever _\bf_\bn_\ba_\bm_\be is specified as the name of a simple command.
When in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, _\bf_\bn_\ba_\bm_\be must be a valid shell _\bn_\ba_\bm_\be and may not
- be the name of one of the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl _\bb_\bu_\bi_\bl_\bt_\bi_\bn_\bs. In default
- mode, a function name can be any unquoted shell word that does
- not contain $\b$. Any redirections (see R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN below) speci-
- fied when a function is defined are performed when the function
- is executed. The exit status of a function definition is zero
- unless a syntax error occurs or a readonly function with the
- same name already exists. When executed, the exit status of a
- function is the exit status of the last command executed in the
+ be the name of one of the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl _\bb_\bu_\bi_\bl_\bt_\bi_\bn_\bs. In default
+ mode, a function name can be any unquoted shell word that does
+ not contain $\b$. Any redirections (see R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN below) speci-
+ fied when a function is defined are performed when the function
+ is executed. The exit status of a function definition is zero
+ unless a syntax error occurs or a readonly function with the
+ same name already exists. When executed, the exit status of a
+ function is the exit status of the last command executed in the
body. (See F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS below.)
C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS
tive shells.
Q\bQU\bUO\bOT\bTI\bIN\bNG\bG
- _\bQ_\bu_\bo_\bt_\bi_\bn_\bg is used to remove the special meaning of certain characters or
- words to the shell. Quoting can be used to disable special treatment
+ _\bQ_\bu_\bo_\bt_\bi_\bn_\bg is used to remove the special meaning of certain characters or
+ words to the shell. Quoting can be used to disable special treatment
for special characters, to prevent reserved words from being recognized
as such, and to prevent parameter expansion.
T\bTO\bOR\bRY\bY E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN below), the _\bh_\bi_\bs_\bt_\bo_\br_\by _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn character, usually !\b!, must
be quoted to prevent history expansion.
- There are three quoting mechanisms: the _\be_\bs_\bc_\ba_\bp_\be _\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br, single
+ There are three quoting mechanisms: the _\be_\bs_\bc_\ba_\bp_\be _\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br, single
quotes, and double quotes.
- A non-quoted backslash (\\b\) is the _\be_\bs_\bc_\ba_\bp_\be _\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br. It preserves the
+ A non-quoted backslash (\\b\) is the _\be_\bs_\bc_\ba_\bp_\be _\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br. It preserves the
literal value of the next character that follows, with the exception of
<newline>. If a \\b\<newline> pair appears, and the backslash is not it-
self quoted, the \\b\<newline> is treated as a line continuation (that is,
it is removed from the input stream and effectively ignored).
- Enclosing characters in single quotes preserves the literal value of
+ Enclosing characters in single quotes preserves the literal value of
each character within the quotes. A single quote may not occur between
single quotes, even when preceded by a backslash.
Enclosing characters in double quotes preserves the literal value of
all characters within the quotes, with the exception of $\b$, `\b`, \\b\, and,
when history expansion is enabled, !\b!. When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be,
- the !\b! has no special meaning within double quotes, even when history
- expansion is enabled. The characters $\b$ and `\b` retain their special
- meaning within double quotes. The backslash retains its special mean-
- ing only when followed by one of the following characters: $\b$, `\b`, "\b", \\b\,
- or <\b<n\bne\bew\bwl\bli\bin\bne\be>\b>. A double quote may be quoted within double quotes by
- preceding it with a backslash. If enabled, history expansion will be
- performed unless an !\b! appearing in double quotes is escaped using a
+ the !\b! has no special meaning within double quotes, even when history
+ expansion is enabled. The characters $\b$ and `\b` retain their special
+ meaning within double quotes. The backslash retains its special mean-
+ ing only when followed by one of the following characters: $\b$, `\b`, "\b", \\b\,
+ or <\b<n\bne\bew\bwl\bli\bin\bne\be>\b>. A double quote may be quoted within double quotes by
+ preceding it with a backslash. If enabled, history expansion will be
+ performed unless an !\b! appearing in double quotes is escaped using a
backslash. The backslash preceding the !\b! is not removed.
- The special parameters *\b* and @\b@ have special meaning when in double
+ The special parameters *\b* and @\b@ have special meaning when in double
quotes (see P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS below).
- Character sequences of the form $\b$'_\bs_\bt_\br_\bi_\bn_\bg' are treated as a special
- variant of single quotes. The sequence expands to _\bs_\bt_\br_\bi_\bn_\bg, with back-
- slash-escaped characters in _\bs_\bt_\br_\bi_\bn_\bg replaced as specified by the ANSI C
- standard. Backslash escape sequences, if present, are decoded as fol-
+ Character sequences of the form $\b$'_\bs_\bt_\br_\bi_\bn_\bg' are treated as a special
+ variant of single quotes. The sequence expands to _\bs_\bt_\br_\bi_\bn_\bg, with back-
+ slash-escaped characters in _\bs_\bt_\br_\bi_\bn_\bg replaced as specified by the ANSI C
+ standard. Backslash escape sequences, if present, are decoded as fol-
lows:
\\b\a\ba alert (bell)
\\b\b\bb backspace
\\b\'\b' single quote
\\b\"\b" double quote
\\b\?\b? question mark
- \\b\_\bn_\bn_\bn the eight-bit character whose value is the octal value
+ \\b\_\bn_\bn_\bn the eight-bit character whose value is the octal value
_\bn_\bn_\bn (one to three octal digits)
- \\b\x\bx_\bH_\bH the eight-bit character whose value is the hexadecimal
+ \\b\x\bx_\bH_\bH the eight-bit character whose value is the hexadecimal
value _\bH_\bH (one or two hex digits)
- \\b\u\bu_\bH_\bH_\bH_\bH the Unicode (ISO/IEC 10646) character whose value is the
+ \\b\u\bu_\bH_\bH_\bH_\bH the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value _\bH_\bH_\bH_\bH (one to four hex digits)
\\b\U\bU_\bH_\bH_\bH_\bH_\bH_\bH_\bH_\bH
- the Unicode (ISO/IEC 10646) character whose value is the
+ the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value _\bH_\bH_\bH_\bH_\bH_\bH_\bH_\bH (one to eight hex digits)
\\b\c\bc_\bx a control-_\bx character
- The expanded result is single-quoted, as if the dollar sign had not
+ The expanded result is single-quoted, as if the dollar sign had not
been present.
A double-quoted string preceded by a dollar sign ($\b$"_\bs_\bt_\br_\bi_\bn_\bg") will cause
current locale is C\bC or P\bPO\bOS\bSI\bIX\bX, if there are no translations available,
or if the string is not translated, the dollar sign is ignored. This
is a form of double quoting, so the string remains double-quoted by de-
- fault, whether or not it is translated and replaced. If the n\bno\boe\bex\bx-\b-
- p\bpa\ban\bnd\bd_\b_t\btr\bra\ban\bns\bsl\bla\bat\bti\bio\bon\bn option is enabled using the s\bsh\bho\bop\bpt\bt builtin, translated
- strings are single-quoted instead of double-quoted. See the descrip-
+ fault, whether or not it is translated and replaced. If the n\bno\boe\bex\bx-\b-
+ p\bpa\ban\bnd\bd_\b_t\btr\bra\ban\bns\bsl\bla\bat\bti\bio\bon\bn option is enabled using the s\bsh\bho\bop\bpt\bt builtin, translated
+ strings are single-quoted instead of double-quoted. See the descrip-
tion of s\bsh\bho\bop\bpt\bt below under S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS.
P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS
- A _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an entity that stores values. It can be a _\bn_\ba_\bm_\be, a num-
- ber, or one of the special characters listed below under S\bSp\bpe\bec\bci\bia\bal\bl P\bPa\bar\bra\bam\bm-\b-
- e\bet\bte\ber\brs\bs. A _\bv_\ba_\br_\bi_\ba_\bb_\bl_\be is a parameter denoted by a _\bn_\ba_\bm_\be. A variable has a
+ A _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an entity that stores values. It can be a _\bn_\ba_\bm_\be, a num-
+ ber, or one of the special characters listed below under S\bSp\bpe\bec\bci\bia\bal\bl P\bPa\bar\bra\ba-\b-
+ m\bme\bet\bte\ber\brs\bs. A _\bv_\ba_\br_\bi_\ba_\bb_\bl_\be is a parameter denoted by a _\bn_\ba_\bm_\be. A variable has a
_\bv_\ba_\bl_\bu_\be and zero or more _\ba_\bt_\bt_\br_\bi_\bb_\bu_\bt_\be_\bs. Attributes are assigned using the
d\bde\bec\bcl\bla\bar\bre\be builtin command (see d\bde\bec\bcl\bla\bar\bre\be below in S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS).
A parameter is set if it has been assigned a value. The null string is
- a valid value. Once a variable is set, it may be unset only by using
+ a valid value. Once a variable is set, it may be unset only by using
the u\bun\bns\bse\bet\bt builtin command (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
A _\bv_\ba_\br_\bi_\ba_\bb_\bl_\be may be assigned to by a statement of the form
_\bn_\ba_\bm_\be=[_\bv_\ba_\bl_\bu_\be]
- If _\bv_\ba_\bl_\bu_\be is not given, the variable is assigned the null string. All
- _\bv_\ba_\bl_\bu_\be_\bs undergo tilde expansion, parameter and variable expansion, com-
- mand substitution, arithmetic expansion, and quote removal (see E\bEX\bXP\bPA\bAN\bN-\b-
+ If _\bv_\ba_\bl_\bu_\be is not given, the variable is assigned the null string. All
+ _\bv_\ba_\bl_\bu_\be_\bs undergo tilde expansion, parameter and variable expansion, com-
+ mand substitution, arithmetic expansion, and quote removal (see E\bEX\bXP\bPA\bAN\bN-\b-
S\bSI\bIO\bON\bN below). If the variable has its i\bin\bnt\bte\beg\bge\ber\br attribute set, then _\bv_\ba_\bl_\bu_\be
- is evaluated as an arithmetic expression even if the $((...)) expansion
+ is evaluated as an arithmetic expression even if the $\b$(\b((\b(...)\b))\b) expansion
is not used (see A\bAr\bri\bit\bth\bhm\bme\bet\bti\bic\bc E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn below). Word splitting and path-
name expansion are not performed. Assignment statements may also ap-
pear as arguments to the a\bal\bli\bia\bas\bs, d\bde\bec\bcl\bla\bar\bre\be, t\bty\byp\bpe\bes\bse\bet\bt, e\bex\bxp\bpo\bor\brt\bt, r\bre\bea\bad\bdo\bon\bnl\bly\by, and
- l\blo\boc\bca\bal\bl builtin commands (_\bd_\be_\bc_\bl_\ba_\br_\ba_\bt_\bi_\bo_\bn commands). When in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be,
- these builtins may appear in a command after one or more instances of
+ l\blo\boc\bca\bal\bl builtin commands (_\bd_\be_\bc_\bl_\ba_\br_\ba_\bt_\bi_\bo_\bn commands). When in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be,
+ these builtins may appear in a command after one or more instances of
the c\bco\bom\bmm\bma\ban\bnd\bd builtin and retain these assignment statement properties.
- In the context where an assignment statement is assigning a value to a
+ In the context where an assignment statement is assigning a value to a
shell variable or array index, the += operator can be used to append to
or add to the variable's previous value. This includes arguments to
- builtin commands such as d\bde\bec\bcl\bla\bar\bre\be that accept assignment statements
- (_\bd_\be_\bc_\bl_\ba_\br_\ba_\bt_\bi_\bo_\bn commands). When += is applied to a variable for which the
+ builtin commands such as d\bde\bec\bcl\bla\bar\bre\be that accept assignment statements (_\bd_\be_\b-
+ _\bc_\bl_\ba_\br_\ba_\bt_\bi_\bo_\bn commands). When += is applied to a variable for which the
i\bin\bnt\bte\beg\bge\ber\br attribute has been set, _\bv_\ba_\bl_\bu_\be is evaluated as an arithmetic ex-
pression and added to the variable's current value, which is also eval-
- uated. When += is applied to an array variable using compound assign-
- ment (see A\bAr\brr\bra\bay\bys\bs below), the variable's value is not unset (as it is
- when using =), and new values are appended to the array beginning at
- one greater than the array's maximum index (for indexed arrays) or
- added as additional key-value pairs in an associative array. When ap-
- plied to a string-valued variable, _\bv_\ba_\bl_\bu_\be is expanded and appended to
+ uated. When += is applied to an array variable using compound assign-
+ ment (see A\bAr\brr\bra\bay\bys\bs below), the variable's value is not unset (as it is
+ when using =), and new values are appended to the array beginning at
+ one greater than the array's maximum index (for indexed arrays) or
+ added as additional key-value pairs in an associative array. When ap-
+ plied to a string-valued variable, _\bv_\ba_\bl_\bu_\be is expanded and appended to
the variable's value.
A variable can be assigned the _\bn_\ba_\bm_\be_\br_\be_\bf attribute using the -\b-n\bn option to
itself), the operation is actually performed on the variable specified
by the nameref variable's value. A nameref is commonly used within
shell functions to refer to a variable whose name is passed as an argu-
- ment to the function. For instance, if a variable name is passed to a
+ ment to the function. For instance, if a variable name is passed to a
shell function as its first argument, running
+
declare -n ref=$1
- inside the function creates a nameref variable r\bre\bef\bf whose value is the
+
+ inside the function creates a nameref variable r\bre\bef\bf whose value is the
variable name passed as the first argument. References and assignments
to r\bre\bef\bf, and changes to its attributes, are treated as references, as-
signments, and attribute modifications to the variable whose name was
attribute, the list of words can be a list of shell variables, and a
name reference will be established for each word in the list, in turn,
when the loop is executed. Array variables cannot be given the n\bna\bam\bme\ber\bre\bef\bf
- attribute. However, nameref variables can reference array variables
- and subscripted array variables. Namerefs can be unset using the -\b-n\bn
- option to the u\bun\bns\bse\bet\bt builtin. Otherwise, if u\bun\bns\bse\bet\bt is executed with the
- name of a nameref variable as an argument, the variable referenced by
+ attribute. However, nameref variables can reference array variables
+ and subscripted array variables. Namerefs can be unset using the -\b-n\bn
+ option to the u\bun\bns\bse\bet\bt builtin. Otherwise, if u\bun\bns\bse\bet\bt is executed with the
+ name of a nameref variable as an argument, the variable referenced by
the nameref variable will be unset.
P\bPo\bos\bsi\bit\bti\bio\bon\bna\bal\bl P\bPa\bar\bra\bam\bme\bet\bte\ber\brs\bs
- A _\bp_\bo_\bs_\bi_\bt_\bi_\bo_\bn_\ba_\bl _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is a parameter denoted by one or more digits,
+ A _\bp_\bo_\bs_\bi_\bt_\bi_\bo_\bn_\ba_\bl _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is a parameter denoted by one or more digits,
other than the single digit 0. Positional parameters are assigned from
the shell's arguments when it is invoked, and may be reassigned using
the s\bse\bet\bt builtin command. Positional parameters may not be assigned to
The shell treats several parameters specially. These parameters may
only be referenced; assignment to them is not allowed.
*\b* Expands to the positional parameters, starting from one. When
- the expansion is not within double quotes, each positional pa-
- rameter expands to a separate word. In contexts where it is
- performed, those words are subject to further word splitting and
- pathname expansion. When the expansion occurs within double
- quotes, it expands to a single word with the value of each pa-
- rameter separated by the first character of the I\bIF\bFS\bS special
- variable. That is, "$\b$*\b*" is equivalent to "$\b$1\b1_\bc$\b$2\b2_\bc.\b..\b..\b.", where _\bc
- is the first character of the value of the I\bIF\bFS\bS variable. If I\bIF\bFS\bS
- is unset, the parameters are separated by spaces. If I\bIF\bFS\bS is
- null, the parameters are joined without intervening separators.
- @\b@ Expands to the positional parameters, starting from one. In
- contexts where word splitting is performed, this expands each
- positional parameter to a separate word; if not within double
- quotes, these words are subject to word splitting. In contexts
- where word splitting is not performed, this expands to a single
- word with each positional parameter separated by a space. When
- the expansion occurs within double quotes, each parameter ex-
- pands to a separate word. That is, "$\b$@\b@" is equivalent to "$\b$1\b1"
- "$\b$2\b2" ... If the double-quoted expansion occurs within a word,
- the expansion of the first parameter is joined with the begin-
- ning part of the original word, and the expansion of the last
- parameter is joined with the last part of the original word.
- When there are no positional parameters, "$\b$@\b@" and $\b$@\b@ expand to
- nothing (i.e., they are removed).
+ the expansion is not within double quotes, each positional para-
+ meter expands to a separate word. In contexts where it is per-
+ formed, those words are subject to further word splitting and
+ pathname expansion. When the expansion occurs within double
+ quotes, it expands to a single word with the value of each para-
+ meter separated by the first character of the I\bIF\bFS\bS special vari-
+ able. That is, "\b"$\b$*\b*"\b" is equivalent to "\b"$\b$1\b1_\bc$\b$2\b2_\bc.\b..\b..\b."\b", where _\bc is
+ the first character of the value of the I\bIF\bFS\bS variable. If I\bIF\bFS\bS is
+ unset, the parameters are separated by spaces. If I\bIF\bFS\bS is null,
+ the parameters are joined without intervening separators.
+ @\b@ Expands to the positional parameters, starting from one. In
+ contexts where word splitting is performed, this expands each
+ positional parameter to a separate word; if not within double
+ quotes, these words are subject to word splitting. In contexts
+ where word splitting is not performed, this expands to a single
+ word with each positional parameter separated by a space. When
+ the expansion occurs within double quotes, each parameter ex-
+ pands to a separate word. That is, "\b"$\b$@\b@"\b" is equivalent to
+ "\b"$\b$1\b1"\b" "\b"$\b$2\b2"\b" .\b..\b..\b. If the double-quoted expansion occurs within a
+ word, the expansion of the first parameter is joined with the
+ beginning part of the original word, and the expansion of the
+ last parameter is joined with the last part of the original
+ word. When there are no positional parameters, "\b"$\b$@\b@"\b" and $\b$@\b@ ex-
+ pand to nothing (i.e., they are removed).
#\b# Expands to the number of positional parameters in decimal.
- ?\b? Expands to the exit status of the most recently executed fore-
+ ?\b? Expands to the exit status of the most recently executed fore-
ground pipeline.
- -\b- Expands to the current option flags as specified upon invoca-
- tion, by the s\bse\bet\bt builtin command, or those set by the shell it-
+ -\b- Expands to the current option flags as specified upon invoca-
+ tion, by the s\bse\bet\bt builtin command, or those set by the shell it-
self (such as the -\b-i\bi option).
- $\b$ Expands to the process ID of the shell. In a subshell, it ex-
+ $\b$ Expands to the process ID of the shell. In a subshell, it ex-
pands to the process ID of the current shell, not the subshell.
- !\b! Expands to the process ID of the job most recently placed into
- the background, whether executed as an asynchronous command or
+ !\b! Expands to the process ID of the job most recently placed into
+ the background, whether executed as an asynchronous command or
using the b\bbg\bg builtin (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL below).
- 0\b0 Expands to the name of the shell or shell script. This is set
+ 0\b0 Expands to the name of the shell or shell script. This is set
at shell initialization. If b\bba\bas\bsh\bh is invoked with a file of com-
mands, $\b$0\b0 is set to the name of that file. If b\bba\bas\bsh\bh is started
with the -\b-c\bc option, then $\b$0\b0 is set to the first argument after
A colon-separated list of enabled shell options. Each word in
the list is a valid argument for the -\b-s\bs option to the s\bsh\bho\bop\bpt\bt
builtin command (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below). The options
- appearing in B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS are those reported as _\bo_\bn by s\bsh\bho\bop\bpt\bt. If
- this variable is in the environment when b\bba\bas\bsh\bh starts up, each
- shell option in the list will be enabled before reading any
+ appearing in B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS are those reported as _\bo_\bn by s\bsh\bho\bop\bpt\bt. If
+ this variable is in the environment when b\bba\bas\bsh\bh starts up, each
+ shell option in the list will be enabled before reading any
startup files. This variable is read-only.
B\bBA\bAS\bSH\bHP\bPI\bID\bD
- Expands to the process ID of the current b\bba\bas\bsh\bh process. This
- differs from $\b$$\b$ under certain circumstances, such as subshells
- that do not require b\bba\bas\bsh\bh to be re-initialized. Assignments to
- B\bBA\bAS\bSH\bHP\bPI\bID\bD have no effect. If B\bBA\bAS\bSH\bHP\bPI\bID\bD is unset, it loses its spe-
+ Expands to the process ID of the current b\bba\bas\bsh\bh process. This
+ differs from $\b$$\b$ under certain circumstances, such as subshells
+ that do not require b\bba\bas\bsh\bh to be re-initialized. Assignments to
+ B\bBA\bAS\bSH\bHP\bPI\bID\bD have no effect. If B\bBA\bAS\bSH\bHP\bPI\bID\bD is unset, it loses its spe-
cial properties, even if it is subsequently reset.
B\bBA\bAS\bSH\bH_\b_A\bAL\bLI\bIA\bAS\bSE\bES\bS
- An associative array variable whose members correspond to the
- internal list of aliases as maintained by the a\bal\bli\bia\bas\bs builtin.
- Elements added to this array appear in the alias list; however,
- unsetting array elements currently does not cause aliases to be
+ An associative array variable whose members correspond to the
+ internal list of aliases as maintained by the a\bal\bli\bia\bas\bs builtin.
+ Elements added to this array appear in the alias list; however,
+ unsetting array elements currently does not cause aliases to be
removed from the alias list. If B\bBA\bAS\bSH\bH_\b_A\bAL\bLI\bIA\bAS\bSE\bES\bS is unset, it loses
its special properties, even if it is subsequently reset.
B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC
An array variable whose values are the number of parameters in
each frame of the current b\bba\bas\bsh\bh execution call stack. The number
- of parameters to the current subroutine (shell function or
- script executed with .\b. or s\bso\bou\bur\brc\bce\be) is at the top of the stack.
- When a subroutine is executed, the number of parameters passed
+ of parameters to the current subroutine (shell function or
+ script executed with .\b. or s\bso\bou\bur\brc\bce\be) is at the top of the stack.
+ When a subroutine is executed, the number of parameters passed
is pushed onto B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC. The shell sets B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC only when in
extended debugging mode (see the description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg op-
- tion to the s\bsh\bho\bop\bpt\bt builtin below). Setting e\bex\bxt\btd\bde\beb\bbu\bug\bg after the
+ tion to the s\bsh\bho\bop\bpt\bt builtin below). Setting e\bex\bxt\btd\bde\beb\bbu\bug\bg after the
shell has started to execute a script, or referencing this vari-
able when e\bex\bxt\btd\bde\beb\bbu\bug\bg is not set, may result in inconsistent val-
ues. Assignments to B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC have no effect, and it may not be
unset.
B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV
- An array variable containing all of the parameters in the cur-
+ An array variable containing all of the parameters in the cur-
rent b\bba\bas\bsh\bh execution call stack. The final parameter of the last
subroutine call is at the top of the stack; the first parameter
of the initial call is at the bottom. When a subroutine is exe-
- cuted, the parameters supplied are pushed onto B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV. The
- shell sets B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV only when in extended debugging mode (see
- the description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin be-
+ cuted, the parameters supplied are pushed onto B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV. The
+ shell sets B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV only when in extended debugging mode (see
+ the description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin be-
low). Setting e\bex\bxt\btd\bde\beb\bbu\bug\bg after the shell has started to execute a
script, or referencing this variable when e\bex\bxt\btd\bde\beb\bbu\bug\bg is not set,
may result in inconsistent values. Assignments to B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV
B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0
When referenced, this variable expands to the name of the shell
or shell script (identical to $\b$0\b0; see the description of special
- parameter 0 above). Assignment to B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0 causes the value
- assigned to also be assigned to $\b$0\b0. If B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0 is unset, it
+ parameter 0 above). Assignment to B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0 causes the value
+ assigned to also be assigned to $\b$0\b0. If B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0 is unset, it
loses its special properties, even if it is subsequently reset.
B\bBA\bAS\bSH\bH_\b_C\bCM\bMD\bDS\bS
- An associative array variable whose members correspond to the
- internal hash table of commands as maintained by the h\bha\bas\bsh\bh
+ An associative array variable whose members correspond to the
+ internal hash table of commands as maintained by the h\bha\bas\bsh\bh
builtin. Elements added to this array appear in the hash table;
however, unsetting array elements currently does not cause com-
mand names to be removed from the hash table. If B\bBA\bAS\bSH\bH_\b_C\bCM\bMD\bDS\bS is
B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD
The command currently being executed or about to be executed,
unless the shell is executing a command as the result of a trap,
- in which case it is the command executing at the time of the
- trap. If B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD is unset, it loses its special proper-
+ in which case it is the command executing at the time of the
+ trap. If B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD is unset, it loses its special proper-
ties, even if it is subsequently reset.
B\bBA\bAS\bSH\bH_\b_E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN_\b_S\bST\bTR\bRI\bIN\bNG\bG
The command argument to the -\b-c\bc invocation option.
B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO
- An array variable whose members are the line numbers in source
- files where each corresponding member of F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE was invoked.
+ An array variable whose members are the line numbers in source
+ files where each corresponding member of F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE was invoked.
$\b${\b{B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO[\b[_\b$_\bi]\b]}\b} is the line number in the source file
($\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi_\b+_\b1]\b]}\b}) where $\b${\b{F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE[\b[_\b$_\bi]\b]}\b} was called (or
- $\b${\b{B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO[\b[_\b$_\bi_\b-_\b1]\b]}\b} if referenced within another shell func-
- tion). Use L\bLI\bIN\bNE\bEN\bNO\bO to obtain the current line number. Assign-
+ $\b${\b{B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO[\b[_\b$_\bi_\b-_\b1]\b]}\b} if referenced within another shell func-
+ tion). Use L\bLI\bIN\bNE\bEN\bNO\bO to obtain the current line number. Assign-
ments to B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO have no effect, and it may not be unset.
B\bBA\bAS\bSH\bH_\b_L\bLO\bOA\bAD\bDA\bAB\bBL\bLE\bES\bS_\b_P\bPA\bAT\bTH\bH
- A colon-separated list of directories in which the shell looks
- for dynamically loadable builtins specified by the e\ben\bna\bab\bbl\ble\be com-
+ A colon-separated list of directories in which the shell looks
+ for dynamically loadable builtins specified by the e\ben\bna\bab\bbl\ble\be com-
mand.
B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH
- An array variable whose members are assigned by the =\b=~\b~ binary
- operator to the [\b[[\b[ conditional command. The element with index
- 0 is the portion of the string matching the entire regular ex-
+ An array variable whose members are assigned by the =\b=~\b~ binary
+ operator to the [\b[[\b[ conditional command. The element with index
+ 0 is the portion of the string matching the entire regular ex-
pression. The element with index _\bn is the portion of the string
matching the _\bnth parenthesized subexpression.
B\bBA\bAS\bSH\bH_\b_M\bMO\bON\bNO\bOS\bSE\bEC\bCO\bON\bND\bDS\bS
An array variable whose members are the source filenames where
the corresponding shell function names in the F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE array
variable are defined. The shell function $\b${\b{F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE[\b[_\b$_\bi]\b]}\b} is de-
- fined in the file $\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi]\b]}\b} and called from
- $\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi_\b+_\b1]\b]}\b}. Assignments to B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE have no ef-
+ fined in the file $\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi]\b]}\b} and called from
+ $\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi_\b+_\b1]\b]}\b}. Assignments to B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE have no ef-
fect, and it may not be unset.
B\bBA\bAS\bSH\bH_\b_S\bSU\bUB\bBS\bSH\bHE\bEL\bLL\bL
- Incremented by one within each subshell or subshell environment
- when the shell begins executing in that environment. The ini-
- tial value is 0. If B\bBA\bAS\bSH\bH_\b_S\bSU\bUB\bBS\bSH\bHE\bEL\bLL\bL is unset, it loses its spe-
+ Incremented by one within each subshell or subshell environment
+ when the shell begins executing in that environment. The ini-
+ tial value is 0. If B\bBA\bAS\bSH\bH_\b_S\bSU\bUB\bBS\bSH\bHE\bEL\bLL\bL is unset, it loses its spe-
cial properties, even if it is subsequently reset.
B\bBA\bAS\bSH\bH_\b_T\bTR\bRA\bAP\bPS\bSI\bIG\bG
- Set to the signal number corresponding to the trap action being
- executed during its execution. See the description of t\btr\bra\bap\bp un-
- der S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below for information about signal
+ Set to the signal number corresponding to the trap action being
+ executed during its execution. See the description of t\btr\bra\bap\bp un-
+ der S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below for information about signal
numbers and trap execution.
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO
A readonly array variable whose members hold version information
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[1]\b] The minor version number (the _\bv_\be_\br_\bs_\bi_\bo_\bn).
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[2]\b] The patch level.
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[3]\b] The build version.
- B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[4]\b] The release status (e.g., _\bb_\be_\bt_\ba_\b1).
+ B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[4]\b] The release status (e.g., _\bb_\be_\bt_\ba).
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[5]\b] The value of M\bMA\bAC\bCH\bHT\bTY\bYP\bPE\bE.
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIO\bON\bN
Expands to a string describing the version of this instance of
C\bCO\bOM\bMP\bP_\b_C\bCW\bWO\bOR\bRD\bD
An index into $\b${\b{C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDS\bS}\b} of the word containing the current
cursor position. This variable is available only in shell func-
- tions invoked by the programmable completion facilities (see
+ tions invoked by the programmable completion facilities (see
P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
C\bCO\bOM\bMP\bP_\b_K\bKE\bEY\bY
The key (or final key of a key sequence) used to invoke the cur-
rent completion function.
C\bCO\bOM\bMP\bP_\b_L\bLI\bIN\bNE\bE
The current command line. This variable is available only in
- shell functions and external commands invoked by the program-
- mable completion facilities (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
+ shell functions and external commands invoked by the programma-
+ ble completion facilities (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
C\bCO\bOM\bMP\bP_\b_P\bPO\bOI\bIN\bNT\bT
The index of the current cursor position relative to the begin-
ning of the current command. If the current cursor position is
at the end of the current command, the value of this variable is
- equal to $\b${\b{#\b#C\bCO\bOM\bMP\bP_\b_L\bLI\bIN\bNE\bE}\b}. This variable is available only in
- shell functions and external commands invoked by the program-
- mable completion facilities (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
+ equal to $\b${\b{#\b#C\bCO\bOM\bMP\bP_\b_L\bLI\bIN\bNE\bE}\b}. This variable is available only in
+ shell functions and external commands invoked by the programma-
+ ble completion facilities (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
C\bCO\bOM\bMP\bP_\b_T\bTY\bYP\bPE\bE
- Set to an integer value corresponding to the type of completion
- attempted that caused a completion function to be called: _\bT_\bA_\bB,
- for normal completion, _\b?, for listing completions after succes-
- sive tabs, _\b!, for listing alternatives on partial word comple-
- tion, _\b@, to list completions if the word is not unmodified, or
- _\b%, for menu completion. This variable is available only in
- shell functions and external commands invoked by the program-
- mable completion facilities (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
+ Set to an integer value corresponding to the type of completion
+ attempted that caused a completion function to be called: _\bT_\bA_\bB,
+ for normal completion, _\b?, for listing completions after succes-
+ sive tabs, _\b!, for listing alternatives on partial word comple-
+ tion, _\b@, to list completions if the word is not unmodified, or
+ _\b%, for menu completion. This variable is available only in
+ shell functions and external commands invoked by the programma-
+ ble completion facilities (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS
- The set of characters that the r\bre\bea\bad\bdl\bli\bin\bne\be library treats as word
- separators when performing word completion. If C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS
- is unset, it loses its special properties, even if it is subse-
+ The set of characters that the r\bre\bea\bad\bdl\bli\bin\bne\be library treats as word
+ separators when performing word completion. If C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS
+ is unset, it loses its special properties, even if it is subse-
quently reset.
C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDS\bS
- An array variable (see A\bAr\brr\bra\bay\bys\bs below) consisting of the individ-
- ual words in the current command line. The line is split into
- words as r\bre\bea\bad\bdl\bli\bin\bne\be would split it, using C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS as de-
- scribed above. This variable is available only in shell func-
- tions invoked by the programmable completion facilities (see
+ An array variable (see A\bAr\brr\bra\bay\bys\bs below) consisting of the individ-
+ ual words in the current command line. The line is split into
+ words as r\bre\bea\bad\bdl\bli\bin\bne\be would split it, using C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS as de-
+ scribed above. This variable is available only in shell func-
+ tions invoked by the programmable completion facilities (see
P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below).
- C\bCO\bOP\bPR\bRO\bOC\bC An array variable (see A\bAr\brr\bra\bay\bys\bs below) created to hold the file
- descriptors for output from and input to an unnamed coprocess
+ C\bCO\bOP\bPR\bRO\bOC\bC An array variable (see A\bAr\brr\bra\bay\bys\bs below) created to hold the file
+ descriptors for output from and input to an unnamed coprocess
(see C\bCo\bop\bpr\bro\boc\bce\bes\bss\bse\bes\bs above).
D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK
An array variable (see A\bAr\brr\bra\bay\bys\bs below) containing the current con-
tents of the directory stack. Directories appear in the stack
in the order they are displayed by the d\bdi\bir\brs\bs builtin. Assigning
to members of this array variable may be used to modify directo-
- ries already in the stack, but the p\bpu\bus\bsh\bhd\bd and p\bpo\bop\bpd\bd builtins must
+ ries already in the stack, but the p\bpu\bus\bsh\bhd\bd and p\bpo\bop\bpd\bd builtins must
be used to add and remove directories. Assignment to this vari-
able will not change the current directory. If D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK is un-
set, it loses its special properties, even if it is subsequently
its special properties, even if it is subsequently reset.
E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS
Each time this parameter is referenced, it expands to the number
- of seconds since the Unix Epoch (see _\bt_\bi_\bm_\be(3)). Assignments to
- E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS are ignored. If E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS is unset, it loses
+ of seconds since the Unix Epoch (see _\bt_\bi_\bm_\be(3)). Assignments to
+ E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS are ignored. If E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS is unset, it loses
its special properties, even if it is subsequently reset.
- E\bEU\bUI\bID\bD Expands to the effective user ID of the current user, initial-
+ E\bEU\bUI\bID\bD Expands to the effective user ID of the current user, initial-
ized at shell startup. This variable is readonly.
F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE
- An array variable containing the names of all shell functions
+ An array variable containing the names of all shell functions
currently in the execution call stack. The element with index 0
is the name of any currently-executing shell function. The bot-
- tom-most element (the one with the highest index) is "main".
- This variable exists only when a shell function is executing.
- Assignments to F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE have no effect. If F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE is unset,
- it loses its special properties, even if it is subsequently re-
+ tom-most element (the one with the highest index) is "main".
+ This variable exists only when a shell function is executing.
+ Assignments to F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE have no effect. If F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE is unset,
+ it loses its special properties, even if it is subsequently re-
set.
- This variable can be used with B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO and B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE.
- Each element of F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE has corresponding elements in
+ This variable can be used with B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO and B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE.
+ Each element of F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE has corresponding elements in
B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO and B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE to describe the call stack. For in-
stance, $\b${\b{F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE[\b[_\b$_\bi]\b]}\b} was called from the file
$\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi_\b+_\b1]\b]}\b} at line number $\b${\b{B\bBA\bAS\bSH\bH_\b_L\bLI\bIN\bNE\bEN\bNO\bO[\b[_\b$_\bi]\b]}\b}. The
c\bca\bal\bll\ble\ber\br builtin displays the current call stack using this infor-
mation.
- G\bGR\bRO\bOU\bUP\bPS\bS An array variable containing the list of groups of which the
+ G\bGR\bRO\bOU\bUP\bPS\bS An array variable containing the list of groups of which the
current user is a member. Assignments to G\bGR\bRO\bOU\bUP\bPS\bS have no effect.
If G\bGR\bRO\bOU\bUP\bPS\bS is unset, it loses its special properties, even if it
is subsequently reset.
H\bHO\bOS\bST\bTN\bNA\bAM\bME\bE
Automatically set to the name of the current host.
H\bHO\bOS\bST\bTT\bTY\bYP\bPE\bE
- Automatically set to a string that uniquely describes the type
- of machine on which b\bba\bas\bsh\bh is executing. The default is system-
+ Automatically set to a string that uniquely describes the type
+ of machine on which b\bba\bas\bsh\bh is executing. The default is system-
dependent.
- L\bLI\bIN\bNE\bEN\bNO\bO Each time this parameter is referenced, the shell substitutes a
- decimal number representing the current sequential line number
- (starting with 1) within a script or function. When not in a
- script or function, the value substituted is not guaranteed to
+ L\bLI\bIN\bNE\bEN\bNO\bO Each time this parameter is referenced, the shell substitutes a
+ decimal number representing the current sequential line number
+ (starting with 1) within a script or function. When not in a
+ script or function, the value substituted is not guaranteed to
be meaningful. If L\bLI\bIN\bNE\bEN\bNO\bO is unset, it loses its special proper-
ties, even if it is subsequently reset.
M\bMA\bAC\bCH\bHT\bTY\bYP\bPE\bE
(see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_M\bMA\bAR\bRK\bK
The position of the mark (saved insertion point) in the r\bre\bea\bad\bdl\bli\bin\bne\be
- line buffer, for use with "bind -x" (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
+ line buffer, for use with "bind -x" (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
below). The characters between the insertion point and the mark
are often called the _\br_\be_\bg_\bi_\bo_\bn.
R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT
The position of the insertion point in the r\bre\bea\bad\bdl\bli\bin\bne\be line buffer,
for use with "bind -x" (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
- R\bRE\bEP\bPL\bLY\bY Set to the line of input read by the r\bre\bea\bad\bd builtin command when
+ R\bRE\bEP\bPL\bLY\bY Set to the line of input read by the r\bre\bea\bad\bd builtin command when
no arguments are supplied.
S\bSE\bEC\bCO\bON\bND\bDS\bS
Each time this parameter is referenced, it expands to the number
A colon-separated list of enabled shell options. Each word in
the list is a valid argument for the -\b-o\bo option to the s\bse\bet\bt
builtin command (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below). The options
- appearing in S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS are those reported as _\bo_\bn by s\bse\bet\bt -\b-o\bo. If
- this variable is in the environment when b\bba\bas\bsh\bh starts up, each
- shell option in the list will be enabled before reading any
+ appearing in S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS are those reported as _\bo_\bn by s\bse\bet\bt -\b-o\bo. If
+ this variable is in the environment when b\bba\bas\bsh\bh starts up, each
+ shell option in the list will be enabled before reading any
startup files. This variable is read-only.
S\bSH\bHL\bLV\bVL\bL Incremented by one each time an instance of b\bba\bas\bsh\bh is started.
S\bSR\bRA\bAN\bND\bDO\bOM\bM
This variable expands to a 32-bit pseudo-random number each time
it is referenced. The random number generator is not linear on
- systems that support /dev/urandom or _\ba_\br_\bc_\b4_\br_\ba_\bn_\bd_\bo_\bm, so each re-
+ systems that support _\b/_\bd_\be_\bv_\b/_\bu_\br_\ba_\bn_\bd_\bo_\bm or _\ba_\br_\bc_\b4_\br_\ba_\bn_\bd_\bo_\bm(3), so each re-
turned number has no relationship to the numbers preceding it.
The random number generator cannot be seeded, so assignments to
this variable have no effect. If S\bSR\bRA\bAN\bND\bDO\bOM\bM is unset, it loses its
signs a default value to a variable; these cases are noted below.
B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT
- The value is used to set the shell's compatibility level. See
- S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE below for a description of the various
+ The value is used to set the shell's compatibility level. See
+ S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE below for a description of the various
compatibility levels and their effects. The value may be a dec-
imal number (e.g., 4.2) or an integer (e.g., 42) corresponding
to the desired compatibility level. If B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT is unset or
default for the current version. If B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT is set to a
value that is not one of the valid compatibility levels, the
shell prints an error message and sets the compatibility level
- to the default for the current version. The valid values corre-
- spond to the compatibility levels described below under S\bSH\bHE\bEL\bLL\bL
- C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE. For example, 4.2 and 42 are valid values
- that correspond to the c\bco\bom\bmp\bpa\bat\bt4\b42\b2 s\bsh\bho\bop\bpt\bt option and set the compat-
- ibility level to 42. The current version is also a valid value.
+ to the default for the current version. A subset of the valid
+ values correspond to the compatibility levels described below
+ under S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE. For example, 4.2 and 42 are
+ valid values that correspond to the c\bco\bom\bmp\bpa\bat\bt4\b42\b2 s\bsh\bho\bop\bpt\bt option and
+ set the compatibility level to 42. The current version is also
+ a valid value.
B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV
- If this parameter is set when b\bba\bas\bsh\bh is executing a shell script,
- its value is interpreted as a filename containing commands to
+ If this parameter is set when b\bba\bas\bsh\bh is executing a shell script,
+ its value is interpreted as a filename containing commands to
initialize the shell, as in _\b~_\b/_\b._\bb_\ba_\bs_\bh_\br_\bc. The value of B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV is
subjected to parameter expansion, command substitution, and
arithmetic expansion before being interpreted as a filename.
P\bPA\bAT\bTH\bH is not used to search for the resultant filename.
B\bBA\bAS\bSH\bH_\b_X\bXT\bTR\bRA\bAC\bCE\bEF\bFD\bD
If set to an integer corresponding to a valid file descriptor,
- b\bba\bas\bsh\bh will write the trace output generated when _\bs_\be_\bt _\b-_\bx is en-
+ b\bba\bas\bsh\bh will write the trace output generated when "set -x" is en-
abled to that file descriptor. The file descriptor is closed
when B\bBA\bAS\bSH\bH_\b_X\bXT\bTR\bRA\bAC\bCE\bEF\bFD\bD is unset or assigned a new value. Unsetting
B\bBA\bAS\bSH\bH_\b_X\bXT\bTR\bRA\bAC\bCE\bEF\bFD\bD or assigning it the empty string causes the trace
output to be sent to the standard error. Note that setting
B\bBA\bAS\bSH\bH_\b_X\bXT\bTR\bRA\bAC\bCE\bEF\bFD\bD to 2 (the standard error file descriptor) and then
unsetting it will result in the standard error being closed.
- C\bCD\bDP\bPA\bAT\bTH\bH The search path for the c\bcd\bd command. This is a colon-separated
+ C\bCD\bDP\bPA\bAT\bTH\bH The search path for the c\bcd\bd command. This is a colon-separated
list of directories in which the shell looks for destination di-
rectories specified by the c\bcd\bd command. A sample value is
".:~:/usr".
receipt of a S\bSI\bIG\bGW\bWI\bIN\bNC\bCH\bH.
C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY
An array variable from which b\bba\bas\bsh\bh reads the possible completions
- generated by a shell function invoked by the programmable com-
- pletion facility (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below). Each ar-
+ generated by a shell function invoked by the programmable com-
+ pletion facility (see P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn below). Each ar-
ray element contains one possible completion.
- E\bEM\bMA\bAC\bCS\bS If b\bba\bas\bsh\bh finds this variable in the environment when the shell
- starts with value "t", it assumes that the shell is running in
+ E\bEM\bMA\bAC\bCS\bS If b\bba\bas\bsh\bh finds this variable in the environment when the shell
+ starts with value "t", it assumes that the shell is running in
an Emacs shell buffer and disables line editing.
- E\bEN\bNV\bV Expanded and executed similarly to B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN
+ E\bEN\bNV\bV Expanded and executed similarly to B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN
above) when an interactive shell is invoked in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be.
E\bEX\bXE\bEC\bCI\bIG\bGN\bNO\bOR\bRE\bE
- A colon-separated list of shell patterns (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg)
- defining the list of filenames to be ignored by command search
- using P\bPA\bAT\bTH\bH. Files whose full pathnames match one of these pat-
- terns are not considered executable files for the purposes of
+ A colon-separated list of shell patterns (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg)
+ defining the list of filenames to be ignored by command search
+ using P\bPA\bAT\bTH\bH. Files whose full pathnames match one of these pat-
+ terns are not considered executable files for the purposes of
completion and command execution via P\bPA\bAT\bTH\bH lookup. This does not
affect the behavior of the [\b[, t\bte\bes\bst\bt, and [\b[[\b[ commands. Full path-
- names in the command hash table are not subject to E\bEX\bXE\bEC\bCI\bIG\bGN\bNO\bOR\bRE\bE.
- Use this variable to ignore shared library files that have the
- executable bit set, but are not executable files. The pattern
+ names in the command hash table are not subject to E\bEX\bXE\bEC\bCI\bIG\bGN\bNO\bOR\bRE\bE.
+ Use this variable to ignore shared library files that have the
+ executable bit set, but are not executable files. The pattern
matching honors the setting of the e\bex\bxt\btg\bgl\blo\bob\bb shell option.
F\bFC\bCE\bED\bDI\bIT\bT The default editor for the f\bfc\bc builtin command.
F\bFI\bIG\bGN\bNO\bOR\bRE\bE
- A colon-separated list of suffixes to ignore when performing
+ A colon-separated list of suffixes to ignore when performing
filename completion (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE below). A filename whose suf-
fix matches one of the entries in F\bFI\bIG\bGN\bNO\bOR\bRE\bE is excluded from the
list of matched filenames. A sample value is ".o:~".
string, and a value of _\b- sorts by name in descending order. Any
invalid value restores the historical sorting behavior.
H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL
- A colon-separated list of values controlling how commands are
- saved on the history list. If the list of values includes _\bi_\bg_\b-
- _\bn_\bo_\br_\be_\bs_\bp_\ba_\bc_\be, lines which begin with a s\bsp\bpa\bac\bce\be character are not
- saved in the history list. A value of _\bi_\bg_\bn_\bo_\br_\be_\bd_\bu_\bp_\bs causes lines
+ A colon-separated list of values controlling how commands are
+ saved on the history list. If the list of values includes
+ _\bi_\bg_\bn_\bo_\br_\be_\bs_\bp_\ba_\bc_\be, lines which begin with a s\bsp\bpa\bac\bce\be character are not
+ saved in the history list. A value of _\bi_\bg_\bn_\bo_\br_\be_\bd_\bu_\bp_\bs causes lines
matching the previous history entry to not be saved. A value of
_\bi_\bg_\bn_\bo_\br_\be_\bb_\bo_\bt_\bh is shorthand for _\bi_\bg_\bn_\bo_\br_\be_\bs_\bp_\ba_\bc_\be and _\bi_\bg_\bn_\bo_\br_\be_\bd_\bu_\bp_\bs. A value
of _\be_\br_\ba_\bs_\be_\bd_\bu_\bp_\bs causes all previous lines matching the current line
Any value not in the above list is ignored. If H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL is
unset, or does not include a valid value, all lines read by the
shell parser are saved on the history list, subject to the value
- of H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE. The second and subsequent lines of a multi-line
- compound command are not tested, and are added to the history
+ of H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE. The second and subsequent lines of a multi-line
+ compound command are not tested, and are added to the history
regardless of the value of H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL.
H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE
The name of the file in which command history is saved (see H\bHI\bIS\bS-\b-
when a shell exits.
H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE
The maximum number of lines contained in the history file. When
- this variable is assigned a value, the history file is trun-
- cated, if necessary, to contain no more than that number of
- lines by removing the oldest entries. The history file is also
- truncated to this size after writing it when a shell exits. If
- the value is 0, the history file is truncated to zero size.
- Non-numeric values and numeric values less than zero inhibit
- truncation. The shell sets the default value to the value of
+ this variable is assigned a value, the history file is trun-
+ cated, if necessary, to contain no more than that number of
+ lines by removing the oldest entries. The history file is also
+ truncated to this size after writing it when a shell exits. If
+ the value is 0, the history file is truncated to zero size.
+ Non-numeric values and numeric values less than zero inhibit
+ truncation. The shell sets the default value to the value of
H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE after reading any startup files.
H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE
- A colon-separated list of patterns used to decide which command
- lines should be saved on the history list. Each pattern is an-
- chored at the beginning of the line and must match the complete
- line (no implicit `*\b*' is appended). Each pattern is tested
- against the line after the checks specified by H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL are
- applied. In addition to the normal shell pattern matching char-
- acters, `&\b&' matches the previous history line. `&\b&' may be es-
- caped using a backslash; the backslash is removed before at-
- tempting a match. The second and subsequent lines of a multi-
+ A colon-separated list of patterns used to decide which command
+ lines should be saved on the history list. Each pattern is an-
+ chored at the beginning of the line and must match the complete
+ line (b\bba\bas\bsh\bh will not implicitly append a "*\b*"). Each pattern is
+ tested against the line after the checks specified by H\bHI\bIS\bST\bTC\bCO\bON\bN-\b-
+ T\bTR\bRO\bOL\bL are applied. In addition to the normal shell pattern
+ matching characters, "&\b&" matches the previous history line. A
+ backslash will escape the "&\b&"; the backslash is removed before
+ attempting a match. The second and subsequent lines of a multi-
line compound command are not tested, and are added to the his-
tory regardless of the value of H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE. The pattern match-
ing honors the setting of the e\bex\bxt\btg\bgl\blo\bob\bb shell option.
The number of commands to remember in the command history (see
H\bHI\bIS\bST\bTO\bOR\bRY\bY below). If the value is 0, commands are not saved in
the history list. Numeric values less than zero result in every
- command being saved on the history list (there is no limit).
- The shell sets the default value to 500 after reading any
+ command being saved on the history list (there is no limit).
+ The shell sets the default value to 500 after reading any
startup files.
H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT
- If this variable is set and not null, its value is used as a
+ If this variable is set and not null, its value is used as a
format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3) to print the time stamp associated
with each history entry displayed by the h\bhi\bis\bst\bto\bor\bry\by builtin. If
this variable is set, time stamps are written to the history
H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE
Contains the name of a file in the same format as _\b/_\be_\bt_\bc_\b/_\bh_\bo_\bs_\bt_\bs
that should be read when the shell needs to complete a hostname.
- The list of possible hostname completions may be changed while
- the shell is running; the next time hostname completion is at-
- tempted after the value is changed, b\bba\bas\bsh\bh adds the contents of
- the new file to the existing list. If H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE is set, but has
- no value, or does not name a readable file, b\bba\bas\bsh\bh attempts to
- read _\b/_\be_\bt_\bc_\b/_\bh_\bo_\bs_\bt_\bs to obtain the list of possible hostname comple-
+ The list of possible hostname completions may be changed while
+ the shell is running; the next time hostname completion is at-
+ tempted after the value is changed, b\bba\bas\bsh\bh adds the contents of
+ the new file to the existing list. If H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE is set, but has
+ no value, or does not name a readable file, b\bba\bas\bsh\bh attempts to
+ read _\b/_\be_\bt_\bc_\b/_\bh_\bo_\bs_\bt_\bs to obtain the list of possible hostname comple-
tions. When H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE is unset, the hostname list is cleared.
I\bIF\bFS\bS The _\bI_\bn_\bt_\be_\br_\bn_\ba_\bl _\bF_\bi_\be_\bl_\bd _\bS_\be_\bp_\ba_\br_\ba_\bt_\bo_\br that is used for word splitting af-
ter expansion and to split lines into words with the r\bre\bea\bad\bd
- builtin command. The default value is ``<space><tab><new-
- line>''.
+ builtin command. The default value is "<space><tab><newline>".
I\bIG\bGN\bNO\bOR\bRE\bEE\bEO\bOF\bF
Controls the action of an interactive shell on receipt of an E\bEO\bOF\bF
character as the sole input. If set, the value is the number of
- consecutive E\bEO\bOF\bF characters which must be typed as the first
- characters on an input line before b\bba\bas\bsh\bh exits. If the variable
- exists but does not have a numeric value, or has no value, the
- default value is 10. If it does not exist, E\bEO\bOF\bF signifies the
+ consecutive E\bEO\bOF\bF characters which must be typed as the first
+ characters on an input line before b\bba\bas\bsh\bh exits. If the variable
+ exists but does not have a numeric value, or has no value, the
+ default value is 10. If it does not exist, E\bEO\bOF\bF signifies the
end of input to the shell.
I\bIN\bNP\bPU\bUT\bTR\bRC\bC
- The filename for the r\bre\bea\bad\bdl\bli\bin\bne\be startup file, overriding the de-
+ The filename for the r\bre\bea\bad\bdl\bli\bin\bne\be startup file, overriding the de-
fault of _\b~_\b/_\b._\bi_\bn_\bp_\bu_\bt_\br_\bc (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE below).
I\bIN\bNS\bSI\bID\bDE\bE_\b_E\bEM\bMA\bAC\bCS\bS
- If this variable appears in the environment when the shell
- starts, b\bba\bas\bsh\bh assumes that it is running inside an Emacs shell
- buffer and may disable line editing, depending on the value of
+ If this variable appears in the environment when the shell
+ starts, b\bba\bas\bsh\bh assumes that it is running inside an Emacs shell
+ buffer and may disable line editing, depending on the value of
T\bTE\bER\bRM\bM.
- L\bLA\bAN\bNG\bG Used to determine the locale category for any category not
+ L\bLA\bAN\bNG\bG Used to determine the locale category for any category not
specifically selected with a variable starting with L\bLC\bC_\b_.
- L\bLC\bC_\b_A\bAL\bLL\bL This variable overrides the value of L\bLA\bAN\bNG\bG and any other L\bLC\bC_\b_
+ L\bLC\bC_\b_A\bAL\bLL\bL This variable overrides the value of L\bLA\bAN\bNG\bG and any other L\bLC\bC_\b_
variable specifying a locale category.
L\bLC\bC_\b_C\bCO\bOL\bLL\bLA\bAT\bTE\bE
- This variable determines the collation order used when sorting
- the results of pathname expansion, and determines the behavior
- of range expressions, equivalence classes, and collating se-
+ This variable determines the collation order used when sorting
+ the results of pathname expansion, and determines the behavior
+ of range expressions, equivalence classes, and collating se-
quences within pathname expansion and pattern matching.
L\bLC\bC_\b_C\bCT\bTY\bYP\bPE\bE
- This variable determines the interpretation of characters and
- the behavior of character classes within pathname expansion and
+ This variable determines the interpretation of characters and
+ the behavior of character classes within pathname expansion and
pattern matching.
L\bLC\bC_\b_M\bME\bES\bSS\bSA\bAG\bGE\bES\bS
- This variable determines the locale used to translate double-
+ This variable determines the locale used to translate double-
quoted strings preceded by a $\b$.
L\bLC\bC_\b_N\bNU\bUM\bME\bER\bRI\bIC\bC
- This variable determines the locale category used for number
+ This variable determines the locale category used for number
formatting.
L\bLC\bC_\b_T\bTI\bIM\bME\bE
- This variable determines the locale category used for data and
+ This variable determines the locale category used for data and
time formatting.
- L\bLI\bIN\bNE\bES\bS Used by the s\bse\bel\ble\bec\bct\bt compound command to determine the column
- length for printing selection lists. Automatically set if the
- c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be option is enabled or in an interactive shell upon
+ L\bLI\bIN\bNE\bES\bS Used by the s\bse\bel\ble\bec\bct\bt compound command to determine the column
+ length for printing selection lists. Automatically set if the
+ c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be option is enabled or in an interactive shell upon
receipt of a S\bSI\bIG\bGW\bWI\bIN\bNC\bCH\bH.
- M\bMA\bAI\bIL\bL If this parameter is set to a file or directory name and the
- M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH variable is not set, b\bba\bas\bsh\bh informs the user of the ar-
+ M\bMA\bAI\bIL\bL If this parameter is set to a file or directory name and the
+ M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH variable is not set, b\bba\bas\bsh\bh informs the user of the ar-
rival of mail in the specified file or Maildir-format directory.
M\bMA\bAI\bIL\bLC\bCH\bHE\bEC\bCK\bK
- Specifies how often (in seconds) b\bba\bas\bsh\bh checks for mail. The de-
- fault is 60 seconds. When it is time to check for mail, the
- shell does so before displaying the primary prompt. If this
- variable is unset, or set to a value that is not a number
+ Specifies how often (in seconds) b\bba\bas\bsh\bh checks for mail. The de-
+ fault is 60 seconds. When it is time to check for mail, the
+ shell does so before displaying the primary prompt. If this
+ variable is unset, or set to a value that is not a number
greater than or equal to zero, the shell disables mail checking.
M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH
A colon-separated list of filenames to be checked for mail. The
message to be printed when mail arrives in a particular file may
- be specified by separating the filename from the message with a
- `?'. When used in the text of the message, $\b$_\b_ expands to the
+ be specified by separating the filename from the message with a
+ "?". When used in the text of the message, $\b$_\b_ expands to the
name of the current mailfile. Example:
- M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH='/var/mail/bfox?"You have mail":~/shell-mail?"$_ has
- mail!"'
+ M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH='/var/mail/bfox?"You have mail":~/shell-mail?"$_ has mail!"'
B\bBa\bas\bsh\bh can be configured to supply a default value for this vari-
able (there is no value by default), but the location of the
user mail files that it uses is system dependent (e.g.,
/var/mail/$\b$U\bUS\bSE\bER\bR).
O\bOP\bPT\bTE\bER\bRR\bR If set to the value 1, b\bba\bas\bsh\bh displays error messages generated by
- the g\bge\bet\bto\bop\bpt\bts\bs builtin command (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
- O\bOP\bPT\bTE\bER\bRR\bR is initialized to 1 each time the shell is invoked or a
+ the g\bge\bet\bto\bop\bpt\bts\bs builtin command (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
+ O\bOP\bPT\bTE\bER\bRR\bR is initialized to 1 each time the shell is invoked or a
shell script is executed.
- P\bPA\bAT\bTH\bH The search path for commands. It is a colon-separated list of
- directories in which the shell looks for commands (see C\bCO\bOM\bMM\bMA\bAN\bND\bD
- E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN below). A zero-length (null) directory name in the
+ P\bPA\bAT\bTH\bH The search path for commands. It is a colon-separated list of
+ directories in which the shell looks for commands (see C\bCO\bOM\bMM\bMA\bAN\bND\bD
+ E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN below). A zero-length (null) directory name in the
value of P\bPA\bAT\bTH\bH indicates the current directory. A null directory
name may appear as two adjacent colons, or as an initial or
trailing colon. The default path is system-dependent, and is
set by the administrator who installs b\bba\bas\bsh\bh. A common value is
- ``/usr/local/bin:/usr/lo-
- cal/sbin:/usr/bin:/usr/sbin:/bin:/sbin''.
+ "/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin".
P\bPO\bOS\bSI\bIX\bXL\bLY\bY_\b_C\bCO\bOR\bRR\bRE\bEC\bCT\bT
If this variable is in the environment when b\bba\bas\bsh\bh starts, the
shell enters _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be before reading the startup files, as if
the -\b--\b-p\bpo\bos\bsi\bix\bx invocation option had been supplied. If it is set
while the shell is running, b\bba\bas\bsh\bh enables _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, as if the
- command _\bs_\be_\bt _\b-_\bo _\bp_\bo_\bs_\bi_\bx had been executed. When the shell enters
+ command "set -o posix" had been executed. When the shell enters
_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it sets this variable if it was not already set.
P\bPR\bRO\bOM\bMP\bPT\bT_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD
- If this variable is set, and is an array, the value of each set
- element is executed as a command prior to issuing each primary
- prompt. If this is set but not an array variable, its value is
+ If this variable is set, and is an array, the value of each set
+ element is executed as a command prior to issuing each primary
+ prompt. If this is set but not an array variable, its value is
used as a command to execute instead.
P\bPR\bRO\bOM\bMP\bPT\bT_\b_D\bDI\bIR\bRT\bTR\bRI\bIM\bM
- If set to a number greater than zero, the value is used as the
+ If set to a number greater than zero, the value is used as the
number of trailing directory components to retain when expanding
the \\b\w\bw and \\b\W\bW prompt string escapes (see P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG below).
Characters removed are replaced with an ellipsis.
before the command is executed.
P\bPS\bS1\b1 The value of this parameter is expanded (see P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG below)
and used as the primary prompt string. The default value is
- ``\\b\s\bs-\b-\\b\v\bv\\b\$\b$ ''.
+ "\s-\v\$ ".
P\bPS\bS2\b2 The value of this parameter is expanded as with P\bPS\bS1\b1 and used as
- the secondary prompt string. The default is ``>\b> ''.
+ the secondary prompt string. The default is "> ".
P\bPS\bS3\b3 The value of this parameter is used as the prompt for the s\bse\bel\ble\bec\bct\bt
command (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR above).
- P\bPS\bS4\b4 The value of this parameter is expanded as with P\bPS\bS1\b1 and the
+ P\bPS\bS4\b4 The value of this parameter is expanded as with P\bPS\bS1\b1 and the
value is printed before each command b\bba\bas\bsh\bh displays during an ex-
ecution trace. The first character of the expanded value of P\bPS\bS4\b4
is replicated multiple times, as necessary, to indicate multiple
- levels of indirection. The default is ``+\b+ ''.
+ levels of indirection. The default is "+ ".
S\bSH\bHE\bEL\bLL\bL This variable expands to the full pathname to the shell. If it
is not set when the shell starts, b\bba\bas\bsh\bh assigns to it the full
pathname of the current user's login shell.
t\bti\bim\bme\be reserved word should be displayed. The %\b% character intro-
duces an escape sequence that is expanded to a time value or
other information. The escape sequences and their meanings are
- as follows; the braces denote optional portions.
+ as follows; the brackets denote optional portions.
%\b%%\b% A literal %\b%.
%\b%[\b[_\bp]\b][\b[l\bl]\b]R\bR The elapsed time in seconds.
%\b%[\b[_\bp]\b][\b[l\bl]\b]U\bU The number of CPU seconds spent in user mode.
The optional _\bp is a digit specifying the _\bp_\br_\be_\bc_\bi_\bs_\bi_\bo_\bn, the number
of fractional digits after a decimal point. A value of 0 causes
- no decimal point or fraction to be output. At most six places
- after the decimal point may be specified; values of _\bp greater
- than 6 are changed to 6. If _\bp is not specified, the value 3 is
+ no decimal point or fraction to be output. At most six places
+ after the decimal point may be specified; values of _\bp greater
+ than 6 are changed to 6. If _\bp is not specified, the value 3 is
used.
- The optional l\bl specifies a longer format, including minutes, of
- the form _\bM_\bMm_\bS_\bS._\bF_\bFs. The value of _\bp determines whether or not
+ The optional l\bl specifies a longer format, including minutes, of
+ the form _\bM_\bMm_\bS_\bS._\bF_\bFs. The value of _\bp determines whether or not
the fraction is included.
- If this variable is not set, b\bba\bas\bsh\bh acts as if it had the value
- $\b$'\b'\\b\n\bnr\bre\bea\bal\bl\\b\t\bt%\b%3\b3l\blR\bR\\b\n\bnu\bus\bse\ber\br\\b\t\bt%\b%3\b3l\blU\bU\\b\n\bns\bsy\bys\bs\\b\t\bt%\b%3\b3l\blS\bS'\b'. If the value is null,
- b\bba\bas\bsh\bh does not display any timing information. A trailing new-
+ If this variable is not set, b\bba\bas\bsh\bh acts as if it had the value
+ $\b$'\b'\\b\n\bnr\bre\bea\bal\bl\\b\t\bt%\b%3\b3l\blR\bR\\b\n\bnu\bus\bse\ber\br\\b\t\bt%\b%3\b3l\blU\bU\\b\n\bns\bsy\bys\bs\\b\t\bt%\b%3\b3l\blS\bS'\b'. If the value is null,
+ b\bba\bas\bsh\bh does not display any timing information. A trailing new-
line is added when the format string is displayed.
T\bTM\bMO\bOU\bUT\bT If set to a value greater than zero, T\bTM\bMO\bOU\bUT\bT is treated as the de-
fault timeout for the r\bre\bea\bad\bd builtin. The s\bse\bel\ble\bec\bct\bt command termi-
nates if input does not arrive after T\bTM\bMO\bOU\bUT\bT seconds when input is
- coming from a terminal. In an interactive shell, the value is
+ coming from a terminal. In an interactive shell, the value is
interpreted as the number of seconds to wait for a line of input
after issuing the primary prompt. B\bBa\bas\bsh\bh terminates after waiting
- for that number of seconds if a complete line of input does not
+ for that number of seconds if a complete line of input does not
arrive.
- T\bTM\bMP\bPD\bDI\bIR\bR If set, b\bba\bas\bsh\bh uses its value as the name of a directory in which
+ T\bTM\bMP\bPD\bDI\bIR\bR If set, b\bba\bas\bsh\bh uses its value as the name of a directory in which
b\bba\bas\bsh\bh creates temporary files for the shell's use.
a\bau\but\bto\bo_\b_r\bre\bes\bsu\bum\bme\be
This variable controls how the shell interacts with the user and
stopped job's name; this provides functionality analogous to the
%\b%_\bs_\bt_\br_\bi_\bn_\bg job identifier.
h\bhi\bis\bst\btc\bch\bha\bar\brs\bs
- The two or three characters which control history expansion and
+ The two or three characters which control history expansion and
tokenization (see H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN below). The first character
is the _\bh_\bi_\bs_\bt_\bo_\br_\by _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn character, the character which signals
- the start of a history expansion, normally `!\b!'. The second
+ the start of a history expansion, normally "!\b!". The second
character is the _\bq_\bu_\bi_\bc_\bk _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn character, which is used as
shorthand for re-running the previous command entered, substi-
tuting one string for another in the command, when it appears as
- the first character on the line. The default is `^\b^'. The op-
+ the first character on the line. The default is "^\b^". The op-
tional third character is the character which indicates that the
remainder of the line is a comment when found as the first char-
- acter of a word, normally `#\b#'. The history comment character
- causes history substitution to be skipped for the remaining
- words on the line. It does not necessarily cause the shell
+ acter of a word, normally "#\b#". The history comment character
+ causes history substitution to be skipped for the remaining
+ words on the line. It does not necessarily cause the shell
parser to treat the rest of the line as a comment.
A\bAr\brr\bra\bay\bys\bs
- B\bBa\bas\bsh\bh provides one-dimensional indexed and associative array variables.
- Any variable may be used as an indexed array; the d\bde\bec\bcl\bla\bar\bre\be builtin will
- explicitly declare an array. There is no maximum limit on the size of
- an array, nor any requirement that members be indexed or assigned con-
- tiguously. Indexed arrays are referenced using integers (including
+ B\bBa\bas\bsh\bh provides one-dimensional indexed and associative array variables.
+ Any variable may be used as an indexed array; the d\bde\bec\bcl\bla\bar\bre\be builtin will
+ explicitly declare an array. There is no maximum limit on the size of
+ an array, nor any requirement that members be indexed or assigned con-
+ tiguously. Indexed arrays are referenced using integers (including
arithmetic expressions) and are zero-based; associative arrays are ref-
erenced using arbitrary strings. Unless otherwise noted, indexed array
indices must be non-negative integers.
- An indexed array is created automatically if any variable is assigned
+ An indexed array is created automatically if any variable is assigned
to using the syntax _\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]=_\bv_\ba_\bl_\bu_\be. The _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt is treated as
an arithmetic expression that must evaluate to a number. To explicitly
- declare an indexed array, use d\bde\bec\bcl\bla\bar\bre\be -\b-a\ba _\bn_\ba_\bm_\be (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bM-\b-
- M\bMA\bAN\bND\bDS\bS below). d\bde\bec\bcl\bla\bar\bre\be -\b-a\ba _\bn_\ba_\bm_\be[\b[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]\b] is also accepted; the _\bs_\bu_\bb_\b-
+ declare an indexed array, use d\bde\bec\bcl\bla\bar\bre\be -\b-a\ba _\bn_\ba_\bm_\be (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bM-\b-
+ M\bMA\bAN\bND\bDS\bS below). d\bde\bec\bcl\bla\bar\bre\be -\b-a\ba _\bn_\ba_\bm_\be[\b[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]\b] is also accepted; the _\bs_\bu_\bb_\b-
_\bs_\bc_\br_\bi_\bp_\bt is ignored.
Associative arrays are created using d\bde\bec\bcl\bla\bar\bre\be -\b-A\bA _\bn_\ba_\bm_\be.
plus one. Indexing starts at zero.
When assigning to an associative array, the words in a compound assign-
- ment may be either assignment statements, for which the subscript is
- required, or a list of words that is interpreted as a sequence of al-
- ternating keys and values: _\bn_\ba_\bm_\be=(\b( _\bk_\be_\by_\b1 _\bv_\ba_\bl_\bu_\be_\b1 _\bk_\be_\by_\b2 _\bv_\ba_\bl_\bu_\be_\b2 ...)\b). These
- are treated identically to _\bn_\ba_\bm_\be=(\b( [_\bk_\be_\by_\b1]=_\bv_\ba_\bl_\bu_\be_\b1 [_\bk_\be_\by_\b2]=_\bv_\ba_\bl_\bu_\be_\b2 ...)\b).
- The first word in the list determines how the remaining words are in-
- terpreted; all assignments in a list must be of the same type. When
- using key/value pairs, the keys may not be missing or empty; a final
+ ment may be either assignment statements, for which the subscript is
+ required, or a list of words that is interpreted as a sequence of al-
+ ternating keys and values: _\bn_\ba_\bm_\be=(\b( _\bk_\be_\by_\b1 _\bv_\ba_\bl_\bu_\be_\b1 _\bk_\be_\by_\b2 _\bv_\ba_\bl_\bu_\be_\b2 ...)\b). These
+ are treated identically to _\bn_\ba_\bm_\be=(\b( [_\bk_\be_\by_\b1]=_\bv_\ba_\bl_\bu_\be_\b1 [_\bk_\be_\by_\b2]=_\bv_\ba_\bl_\bu_\be_\b2 ...)\b).
+ The first word in the list determines how the remaining words are in-
+ terpreted; all assignments in a list must be of the same type. When
+ using key/value pairs, the keys may not be missing or empty; a final
missing value is treated like the empty string.
- This syntax is also accepted by the d\bde\bec\bcl\bla\bar\bre\be builtin. Individual array
- elements may be assigned to using the _\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]=_\bv_\ba_\bl_\bu_\be syntax in-
- troduced above. When assigning to an indexed array, if _\bn_\ba_\bm_\be is sub-
- scripted by a negative number, that number is interpreted as relative
- to one greater than the maximum index of _\bn_\ba_\bm_\be, so negative indices
+ This syntax is also accepted by the d\bde\bec\bcl\bla\bar\bre\be builtin. Individual array
+ elements may be assigned to using the _\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]=_\bv_\ba_\bl_\bu_\be syntax in-
+ troduced above. When assigning to an indexed array, if _\bn_\ba_\bm_\be is sub-
+ scripted by a negative number, that number is interpreted as relative
+ to one greater than the maximum index of _\bn_\ba_\bm_\be, so negative indices
count back from the end of the array, and an index of -1 references the
last element.
Any element of an array may be referenced using ${_\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]}.
The braces are required to avoid conflicts with pathname expansion. If
- _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt is @\b@ or *\b*, the word expands to all members of _\bn_\ba_\bm_\be, unless
- noted in the description of a builtin or word expansion. These sub-
+ _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt is @\b@ or *\b*, the word expands to all members of _\bn_\ba_\bm_\be, unless
+ noted in the description of a builtin or word expansion. These sub-
scripts differ only when the word appears within double quotes. If the
word is double-quoted, ${_\bn_\ba_\bm_\be[*]} expands to a single word with the
value of each array member separated by the first character of the I\bIF\bFS\bS
special variable, and ${_\bn_\ba_\bm_\be[@]} expands each element of _\bn_\ba_\bm_\be to a sep-
- arate word. When there are no array members, ${_\bn_\ba_\bm_\be[@]} expands to
- nothing. If the double-quoted expansion occurs within a word, the ex-
+ arate word. When there are no array members, ${_\bn_\ba_\bm_\be[@]} expands to
+ nothing. If the double-quoted expansion occurs within a word, the ex-
pansion of the first parameter is joined with the beginning part of the
original word, and the expansion of the last parameter is joined with
the last part of the original word. This is analogous to the expansion
- of the special parameters *\b* and @\b@ (see S\bSp\bpe\bec\bci\bia\bal\bl P\bPa\bar\bra\bam\bme\bet\bte\ber\brs\bs above).
- ${#_\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]} expands to the length of ${_\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]}. If
+ of the special parameters *\b* and @\b@ (see S\bSp\bpe\bec\bci\bia\bal\bl P\bPa\bar\bra\bam\bme\bet\bte\ber\brs\bs above).
+ ${#_\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]} expands to the length of ${_\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]}. If
_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt is *\b* or @\b@, the expansion is the number of elements in the ar-
ray. If the _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt used to reference an element of an indexed array
- evaluates to a number less than zero, it is interpreted as relative to
- one greater than the maximum index of the array, so negative indices
+ evaluates to a number less than zero, it is interpreted as relative to
+ one greater than the maximum index of the array, so negative indices
count back from the end of the array, and an index of -1 references the
last element.
Referencing an array variable without a subscript is equivalent to ref-
- erencing the array with a subscript of 0. Any reference to a variable
+ erencing the array with a subscript of 0. Any reference to a variable
using a valid subscript is valid, and b\bba\bas\bsh\bh will create an array if nec-
essary.
The u\bun\bns\bse\bet\bt builtin is used to destroy arrays. u\bun\bns\bse\bet\bt _\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt] de-
stroys the array element at index _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt, for both indexed and asso-
- ciative arrays. Negative subscripts to indexed arrays are interpreted
- as described above. Unsetting the last element of an array variable
- does not unset the variable. u\bun\bns\bse\bet\bt _\bn_\ba_\bm_\be, where _\bn_\ba_\bm_\be is an array, re-
+ ciative arrays. Negative subscripts to indexed arrays are interpreted
+ as described above. Unsetting the last element of an array variable
+ does not unset the variable. u\bun\bns\bse\bet\bt _\bn_\ba_\bm_\be, where _\bn_\ba_\bm_\be is an array, re-
moves the entire array. u\bun\bns\bse\bet\bt _\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt], where _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt is *\b* or
@\b@, behaves differently depending on whether _\bn_\ba_\bm_\be is an indexed or asso-
- ciative array. If _\bn_\ba_\bm_\be is an associative array, this unsets the ele-
+ ciative array. If _\bn_\ba_\bm_\be is an associative array, this unsets the ele-
ment with subscript *\b* or @\b@. If _\bn_\ba_\bm_\be is an indexed array, unset removes
all of the elements but does not remove the array itself.
scribed above, the argument is subject to pathname expansion. If path-
name expansion is not desired, the argument should be quoted.
- The d\bde\bec\bcl\bla\bar\bre\be, l\blo\boc\bca\bal\bl, and r\bre\bea\bad\bdo\bon\bnl\bly\by builtins each accept a -\b-a\ba option to
- specify an indexed array and a -\b-A\bA option to specify an associative ar-
- ray. If both options are supplied, -\b-A\bA takes precedence. The r\bre\bea\bad\bd
- builtin accepts a -\b-a\ba option to assign a list of words read from the
+ The d\bde\bec\bcl\bla\bar\bre\be, l\blo\boc\bca\bal\bl, and r\bre\bea\bad\bdo\bon\bnl\bly\by builtins each accept a -\b-a\ba option to
+ specify an indexed array and a -\b-A\bA option to specify an associative ar-
+ ray. If both options are supplied, -\b-A\bA takes precedence. The r\bre\bea\bad\bd
+ builtin accepts a -\b-a\ba option to assign a list of words read from the
standard input to an array. The s\bse\bet\bt and d\bde\bec\bcl\bla\bar\bre\be builtins display array
values in a way that allows them to be reused as assignments.
E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN
Expansion is performed on the command line after it has been split into
- words. There are seven kinds of expansion performed: _\bb_\br_\ba_\bc_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn,
- _\bt_\bi_\bl_\bd_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br _\ba_\bn_\bd _\bv_\ba_\br_\bi_\ba_\bb_\bl_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bc_\bo_\bm_\bm_\ba_\bn_\bd _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\b-
- _\bt_\bi_\bo_\bn, _\ba_\br_\bi_\bt_\bh_\bm_\be_\bt_\bi_\bc _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bw_\bo_\br_\bd _\bs_\bp_\bl_\bi_\bt_\bt_\bi_\bn_\bg, and _\bp_\ba_\bt_\bh_\bn_\ba_\bm_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn.
+ words. The shell performs these expansions: _\bb_\br_\ba_\bc_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bt_\bi_\bl_\bd_\be _\be_\bx_\b-
+ _\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br _\ba_\bn_\bd _\bv_\ba_\br_\bi_\ba_\bb_\bl_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bc_\bo_\bm_\bm_\ba_\bn_\bd _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn, _\ba_\br_\bi_\bt_\bh_\b-
+ _\bm_\be_\bt_\bi_\bc _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, _\bw_\bo_\br_\bd _\bs_\bp_\bl_\bi_\bt_\bt_\bi_\bn_\bg, _\bp_\ba_\bt_\bh_\bn_\ba_\bm_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, and _\bq_\bu_\bo_\bt_\be _\br_\be_\bm_\bo_\bv_\ba_\bl
+ _\b.
The order of expansions is: brace expansion; tilde expansion, parameter
- and variable expansion, arithmetic expansion, and command substitution
- (done in a left-to-right fashion); word splitting; and pathname expan-
- sion.
+ and variable expansion, arithmetic expansion, and command substitution
+ (done in a left-to-right fashion); word splitting; pathname expansion;
+ and quote removal.
On systems that can support it, there is an additional expansion avail-
able: _\bp_\br_\bo_\bc_\be_\bs_\bs _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn. This is performed at the same time as
tilde, parameter, variable, and arithmetic expansion and command sub-
stitution.
- After these expansions are performed, quote characters present in the
- original word are removed unless they have been quoted themselves
- (_\bq_\bu_\bo_\bt_\be _\br_\be_\bm_\bo_\bv_\ba_\bl).
+ _\bQ_\bu_\bo_\bt_\be _\br_\be_\bm_\bo_\bv_\ba_\bl is always performed last. It removes quote characters
+ present in the original word, not ones resulting from one of the other
+ expansions, unless they have been quoted themselves.
Only brace expansion, word splitting, and pathname expansion can in-
crease the number of words of the expansion; other expansions expand a
single word to a single word. The only exceptions to this are the ex-
- pansions of "$\b$@\b@" and "$\b${\b{_\bn_\ba_\bm_\be[\b[@\b@]\b]}\b}", and, in most cases, $\b$*\b* and
+ pansions of "\b"$\b$@\b@"\b" and "\b"$\b${\b{_\bn_\ba_\bm_\be[\b[@\b@]\b]}\b}"\b", and, in most cases, $\b$*\b* and
$\b${\b{_\bn_\ba_\bm_\be[\b[*\b*]\b]}\b} as explained above (see P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS).
B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
_\bB_\br_\ba_\bc_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn is a mechanism by which arbitrary strings may be gener-
- ated. This mechanism is similar to _\bp_\ba_\bt_\bh_\bn_\ba_\bm_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, but the file-
+ ated. This mechanism is similar to _\bp_\ba_\bt_\bh_\bn_\ba_\bm_\be _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn, but the file-
names generated need not exist. Patterns to be brace expanded take the
form of an optional _\bp_\br_\be_\ba_\bm_\bb_\bl_\be, followed by either a series of comma-sep-
- arated strings or a sequence expression between a pair of braces, fol-
- lowed by an optional _\bp_\bo_\bs_\bt_\bs_\bc_\br_\bi_\bp_\bt. The preamble is prefixed to each
+ arated strings or a sequence expression between a pair of braces, fol-
+ lowed by an optional _\bp_\bo_\bs_\bt_\bs_\bc_\br_\bi_\bp_\bt. The preamble is prefixed to each
string contained within the braces, and the postscript is then appended
to each resulting string, expanding left to right.
Brace expansions may be nested. The results of each expanded string
are not sorted; left to right order is preserved. For example,
- a{\b{d,c,b}\b}e expands into `ade ace abe'.
+ a{\b{d,c,b}\b}e expands into "ade ace abe".
A sequence expression takes the form {\b{_\bx.\b..\b._\by[\b[.\b..\b._\bi_\bn_\bc_\br]\b]}\b}, where _\bx and _\by are
either integers or single letters, and _\bi_\bn_\bc_\br, an optional increment, is
an integer. When integers are supplied, the expression expands to each
- number between _\bx and _\by, inclusive. Supplied integers may be prefixed
- with _\b0 to force each term to have the same width. When either _\bx or _\by
- begins with a zero, the shell attempts to force all generated terms to
- contain the same number of digits, zero-padding where necessary. When
- letters are supplied, the expression expands to each character lexico-
- graphically between _\bx and _\by, inclusive, using the default C locale.
- Note that both _\bx and _\by must be of the same type (integer or letter).
- When the increment is supplied, it is used as the difference between
- each term. The default increment is 1 or -1 as appropriate.
+ number between _\bx and _\by, inclusive. If the supplied integers are pre-
+ fixed with _\b0, each term will have the same width, zero-padding if nec-
+ essary. When either _\bx or _\by begins with a zero, the shell attempts to
+ force all generated terms to contain the same number of digits, zero-
+ padding where necessary. When letters are supplied, the expression ex-
+ pands to each character lexicographically between _\bx and _\by, inclusive,
+ using the default C locale. Note that both _\bx and _\by must be of the same
+ type (integer or letter). When the increment is supplied, it is used
+ as the difference between each term. The default increment is 1 or -1
+ as appropriate.
Brace expansion is performed before any other expansions, and any char-
- acters special to other expansions are preserved in the result. It is
- strictly textual. B\bBa\bas\bsh\bh does not apply any syntactic interpretation to
+ acters special to other expansions are preserved in the result. It is
+ strictly textual. B\bBa\bas\bsh\bh does not apply any syntactic interpretation to
the context of the expansion or the text between the braces.
- A correctly-formed brace expansion must contain unquoted opening and
+ A correctly-formed brace expansion must contain unquoted opening and
closing braces, and at least one unquoted comma or a valid sequence ex-
pression. Any incorrectly formed brace expansion is left unchanged. A
- {\b{ or ,\b, may be quoted with a backslash to prevent its being considered
- part of a brace expression. To avoid conflicts with parameter expan-
+ {\b{ or ,\b, may be quoted with a backslash to prevent its being considered
+ part of a brace expression. To avoid conflicts with parameter expan-
sion, the string $\b${\b{ is not considered eligible for brace expansion, and
inhibits brace expansion until the closing }\b}.
or
chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}}
- Brace expansion introduces a slight incompatibility with historical
- versions of s\bsh\bh. s\bsh\bh does not treat opening or closing braces specially
- when they appear as part of a word, and preserves them in the output.
- B\bBa\bas\bsh\bh removes braces from words as a consequence of brace expansion.
- For example, a word entered to s\bsh\bh as _\bf_\bi_\bl_\be_\b{_\b1_\b,_\b2_\b} appears identically in
- the output. The same word is output as _\bf_\bi_\bl_\be_\b1 _\bf_\bi_\bl_\be_\b2 after expansion by
- b\bba\bas\bsh\bh. If strict compatibility with s\bsh\bh is desired, start b\bba\bas\bsh\bh with the
+ Brace expansion introduces a slight incompatibility with historical
+ versions of s\bsh\bh. s\bsh\bh does not treat opening or closing braces specially
+ when they appear as part of a word, and preserves them in the output.
+ B\bBa\bas\bsh\bh removes braces from words as a consequence of brace expansion.
+ For example, a word entered to s\bsh\bh as _\bf_\bi_\bl_\be_\b{_\b1_\b,_\b2_\b} appears identically in
+ the output. The same word is output as _\bf_\bi_\bl_\be_\b1 _\bf_\bi_\bl_\be_\b2 after expansion by
+ b\bba\bas\bsh\bh. If strict compatibility with s\bsh\bh is desired, start b\bba\bas\bsh\bh with the
+\b+B\bB option or disable brace expansion with the +\b+B\bB option to the s\bse\bet\bt com-
mand (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
T\bTi\bil\bld\bde\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
- If a word begins with an unquoted tilde character (`~\b~'), all of the
+ If a word begins with an unquoted tilde character ("~\b~"), all of the
characters preceding the first unquoted slash (or all characters, if
there is no unquoted slash) are considered a _\bt_\bi_\bl_\bd_\be_\b-_\bp_\br_\be_\bf_\bi_\bx. If none of
the characters in the tilde-prefix are quoted, the characters in the
wise, the tilde-prefix is replaced with the home directory associated
with the specified login name.
- If the tilde-prefix is a `~+', the value of the shell variable P\bPW\bWD\bD re-
- places the tilde-prefix. If the tilde-prefix is a `~-', the value of
+ If the tilde-prefix is a "~+", the value of the shell variable P\bPW\bWD\bD re-
+ places the tilde-prefix. If the tilde-prefix is a "~-", the value of
the shell variable O\bOL\bLD\bDP\bPW\bWD\bD, if it is set, is substituted. If the char-
acters following the tilde in the tilde-prefix consist of a number _\bN,
- optionally prefixed by a `+' or a `-', the tilde-prefix is replaced
+ optionally prefixed by a "+" or a "-", the tilde-prefix is replaced
with the corresponding element from the directory stack, as it would be
displayed by the d\bdi\bir\brs\bs builtin invoked with the tilde-prefix as an argu-
ment. If the characters following the tilde in the tilde-prefix con-
- sist of a number without a leading `+' or `-', `+' is assumed.
+ sist of a number without a leading "+" or "-", "+" is assumed.
If the login name is invalid, or the tilde expansion fails, the word is
unchanged.
B\bBa\bas\bsh\bh also performs tilde expansion on words satisfying the conditions
of variable assignments (as described above under P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS) when they
- appear as arguments to simple commands. B\bBa\bas\bsh\bh does not do this, except
+ appear as arguments to simple commands. B\bBa\bas\bsh\bh does not do this, except
for the _\bd_\be_\bc_\bl_\ba_\br_\ba_\bt_\bi_\bo_\bn commands listed above, when in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be.
P\bPa\bar\bra\bam\bme\bet\bte\ber\br E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
- The `$\b$' character introduces parameter expansion, command substitution,
+ The "$\b$" character introduces parameter expansion, command substitution,
or arithmetic expansion. The parameter name or symbol to be expanded
may be enclosed in braces, which are optional but serve to protect the
variable to be expanded from characters immediately following it which
could be interpreted as part of the name.
- When braces are used, the matching ending brace is the first `}\b}' not
+ When braces are used, the matching ending brace is the first "}\b}" not
escaped by a backslash or within a quoted string, and not within an em-
- bedded arithmetic expansion, command substitution, or parameter expan-
+ bedded arithmetic expansion, command substitution, or parameter expan-
sion.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}
- The value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is substituted. The braces are required
- when _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is a positional parameter with more than one
+ The value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is substituted. The braces are required
+ when _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is a positional parameter with more than one
digit, or when _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is followed by a character which is not
to be interpreted as part of its name. The _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is a shell
- parameter as described above P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS) or an array reference
+ parameter as described above P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS) or an array reference
(A\bAr\brr\bra\bay\bys\bs).
- If the first character of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an exclamation point (!\b!), and
+ If the first character of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an exclamation point (!\b!), and
_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is not a _\bn_\ba_\bm_\be_\br_\be_\bf, it introduces a level of indirection. B\bBa\bas\bsh\bh
uses the value formed by expanding the rest of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br as the new _\bp_\ba_\b-
- _\br_\ba_\bm_\be_\bt_\be_\br; this is then expanded and that value is used in the rest of
- the expansion, rather than the expansion of the original _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br.
+ _\br_\ba_\bm_\be_\bt_\be_\br; this is then expanded and that value is used in the rest of
+ the expansion, rather than the expansion of the original _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br.
This is known as _\bi_\bn_\bd_\bi_\br_\be_\bc_\bt _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn. The value is subject to tilde ex-
pansion, parameter expansion, command substitution, and arithmetic ex-
pansion. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is a nameref, this expands to the name of the
it is not interactive, exits. Otherwise, the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
is substituted.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br:\b:+\b+_\bw_\bo_\br_\bd}
- U\bUs\bse\be A\bAl\blt\bte\ber\brn\bna\bat\bte\be V\bVa\bal\blu\bue\be. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is null or unset, nothing is
+ U\bUs\bse\be A\bAl\blt\bte\ber\brn\bna\bat\bte\be V\bVa\bal\blu\bue\be. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is null or unset, nothing is
substituted, otherwise the expansion of _\bw_\bo_\br_\bd is substituted.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br:\b:_\bo_\bf_\bf_\bs_\be_\bt}
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br:\b:_\bo_\bf_\bf_\bs_\be_\bt:\b:_\bl_\be_\bn_\bg_\bt_\bh}
- S\bSu\bub\bbs\bst\btr\bri\bin\bng\bg E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn. Expands to up to _\bl_\be_\bn_\bg_\bt_\bh characters of the
- value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br starting at the character specified by _\bo_\bf_\bf_\b-
- _\bs_\be_\bt. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, an indexed array subscripted by @\b@
- or *\b*, or an associative array name, the results differ as de-
- scribed below. If _\bl_\be_\bn_\bg_\bt_\bh is omitted, expands to the substring
+ S\bSu\bub\bbs\bst\btr\bri\bin\bng\bg E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn. Expands to up to _\bl_\be_\bn_\bg_\bt_\bh characters of the
+ value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br starting at the character specified by _\bo_\bf_\bf_\b-
+ _\bs_\be_\bt. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, an indexed array subscripted by @\b@
+ or *\b*, or an associative array name, the results differ as de-
+ scribed below. If _\bl_\be_\bn_\bg_\bt_\bh is omitted, expands to the substring
of the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br starting at the character specified by
_\bo_\bf_\bf_\bs_\be_\bt and extending to the end of the value. _\bl_\be_\bn_\bg_\bt_\bh and _\bo_\bf_\bf_\bs_\be_\bt
are arithmetic expressions (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN below).
- If _\bo_\bf_\bf_\bs_\be_\bt evaluates to a number less than zero, the value is
+ If _\bo_\bf_\bf_\bs_\be_\bt evaluates to a number less than zero, the value is
used as an offset in characters from the end of the value of _\bp_\ba_\b-
_\br_\ba_\bm_\be_\bt_\be_\br. If _\bl_\be_\bn_\bg_\bt_\bh evaluates to a number less than zero, it is
interpreted as an offset in characters from the end of the value
- of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br rather than a number of characters, and the expan-
- sion is the characters between _\bo_\bf_\bf_\bs_\be_\bt and that result. Note
- that a negative offset must be separated from the colon by at
+ of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br rather than a number of characters, and the expan-
+ sion is the characters between _\bo_\bf_\bf_\bs_\be_\bt and that result. Note
+ that a negative offset must be separated from the colon by at
least one space to avoid being confused with the :\b:-\b- expansion.
- If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the result is _\bl_\be_\bn_\bg_\bt_\bh positional parame-
- ters beginning at _\bo_\bf_\bf_\bs_\be_\bt. A negative _\bo_\bf_\bf_\bs_\be_\bt is taken relative
- to one greater than the greatest positional parameter, so an
+ If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the result is _\bl_\be_\bn_\bg_\bt_\bh positional parame-
+ ters beginning at _\bo_\bf_\bf_\bs_\be_\bt. A negative _\bo_\bf_\bf_\bs_\be_\bt is taken relative
+ to one greater than the greatest positional parameter, so an
offset of -1 evaluates to the last positional parameter (or 0 if
there are no positional parameters). It is an expansion error
if _\bl_\be_\bn_\bg_\bt_\bh evaluates to a number less than zero.
If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an indexed array name subscripted by @ or *, the
- result is the _\bl_\be_\bn_\bg_\bt_\bh members of the array beginning with ${_\bp_\ba_\b-
- _\br_\ba_\bm_\be_\bt_\be_\br[_\bo_\bf_\bf_\bs_\be_\bt]}. A negative _\bo_\bf_\bf_\bs_\be_\bt is taken relative to one
+ result is the _\bl_\be_\bn_\bg_\bt_\bh members of the array beginning with ${_\bp_\ba_\br_\ba_\b-
+ _\bm_\be_\bt_\be_\br[_\bo_\bf_\bf_\bs_\be_\bt]}. A negative _\bo_\bf_\bf_\bs_\be_\bt is taken relative to one
greater than the maximum index of the specified array. It is an
expansion error if _\bl_\be_\bn_\bg_\bt_\bh evaluates to a number less than zero.
${!\b!_\bp_\br_\be_\bf_\bi_\bx@\b@}
N\bNa\bam\bme\bes\bs m\bma\bat\btc\bch\bhi\bin\bng\bg p\bpr\bre\bef\bfi\bix\bx. Expands to the names of variables whose
names begin with _\bp_\br_\be_\bf_\bi_\bx, separated by the first character of the
- I\bIF\bFS\bS special variable. When _\b@ is used and the expansion appears
- within double quotes, each variable name expands to a separate
+ I\bIF\bFS\bS special variable. When _\b@ is used and the expansion appears
+ within double quotes, each variable name expands to a separate
word.
${!\b!_\bn_\ba_\bm_\be[_\b@]}
${!\b!_\bn_\ba_\bm_\be[_\b*]}
- L\bLi\bis\bst\bt o\bof\bf a\bar\brr\bra\bay\by k\bke\bey\bys\bs. If _\bn_\ba_\bm_\be is an array variable, expands to
- the list of array indices (keys) assigned in _\bn_\ba_\bm_\be. If _\bn_\ba_\bm_\be is
- not an array, expands to 0 if _\bn_\ba_\bm_\be is set and null otherwise.
- When _\b@ is used and the expansion appears within double quotes,
+ L\bLi\bis\bst\bt o\bof\bf a\bar\brr\bra\bay\by k\bke\bey\bys\bs. If _\bn_\ba_\bm_\be is an array variable, expands to
+ the list of array indices (keys) assigned in _\bn_\ba_\bm_\be. If _\bn_\ba_\bm_\be is
+ not an array, expands to 0 if _\bn_\ba_\bm_\be is set and null otherwise.
+ When _\b@ is used and the expansion appears within double quotes,
each key expands to a separate word.
${#\b#_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}
- P\bPa\bar\bra\bam\bme\bet\bte\ber\br l\ble\ben\bng\bgt\bth\bh. The length in characters of the value of _\bp_\ba_\b-
- _\br_\ba_\bm_\be_\bt_\be_\br is substituted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is *\b* or @\b@, the value sub-
- stituted is the number of positional parameters. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
+ P\bPa\bar\bra\bam\bme\bet\bte\ber\br l\ble\ben\bng\bgt\bth\bh. The length in characters of the value of _\bp_\ba_\b-
+ _\br_\ba_\bm_\be_\bt_\be_\br is substituted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is *\b* or @\b@, the value sub-
+ stituted is the number of positional parameters. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
is an array name subscripted by *\b* or @\b@, the value substituted is
the number of elements in the array. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an indexed
- array name subscripted by a negative number, that number is in-
- terpreted as relative to one greater than the maximum index of
- _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br, so negative indices count back from the end of the
+ array name subscripted by a negative number, that number is in-
+ terpreted as relative to one greater than the maximum index of
+ _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br, so negative indices count back from the end of the
array, and an index of -1 references the last element.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br#\b#_\bw_\bo_\br_\bd}
t\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below. If the pattern matches the beginning of
the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br, then the result of the expansion is the
expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br with the shortest matching pattern
- (the ``#\b#'' case) or the longest matching pattern (the ``#\b##\b#''
- case) deleted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the pattern removal op-
- eration is applied to each positional parameter in turn, and the
- expansion is the resultant list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array vari-
- able subscripted with @\b@ or *\b*, the pattern removal operation is
- applied to each member of the array in turn, and the expansion
- is the resultant list.
+ (the "#" case) or the longest matching pattern (the "##" case)
+ deleted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the pattern removal operation
+ is applied to each positional parameter in turn, and the expan-
+ sion is the resultant list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array variable
+ subscripted with @\b@ or *\b*, the pattern removal operation is ap-
+ plied to each member of the array in turn, and the expansion is
+ the resultant list.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br%\b%_\bw_\bo_\br_\bd}
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br%\b%%\b%_\bw_\bo_\br_\bd}
R\bRe\bem\bmo\bov\bve\be m\bma\bat\btc\bch\bhi\bin\bng\bg s\bsu\buf\bff\bfi\bix\bx p\bpa\bat\btt\bte\ber\brn\bn. The _\bw_\bo_\br_\bd is expanded to produce
a pattern just as in pathname expansion, and matched against the
expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br using the rules described under P\bPa\bat\bt-\b-
- t\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below. If the pattern matches a trailing portion
- of the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br, then the result of the ex-
- pansion is the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br with the shortest
- matching pattern (the ``%\b%'' case) or the longest matching pat-
- tern (the ``%\b%%\b%'' case) deleted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the
- pattern removal operation is applied to each positional parame-
- ter in turn, and the expansion is the resultant list. If _\bp_\ba_\br_\ba_\bm_\b-
- _\be_\bt_\be_\br is an array variable subscripted with @\b@ or *\b*, the pattern
- removal operation is applied to each member of the array in
- turn, and the expansion is the resultant list.
+ t\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below. If the pattern matches a trailing portion
+ of the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br, then the result of the ex-
+ pansion is the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br with the shortest
+ matching pattern (the "%" case) or the longest matching pattern
+ (the "%%" case) deleted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the pattern
+ removal operation is applied to each positional parameter in
+ turn, and the expansion is the resultant list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is
+ an array variable subscripted with @\b@ or *\b*, the pattern removal
+ operation is applied to each member of the array in turn, and
+ the expansion is the resultant list.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br/\b/_\bp_\ba_\bt_\bt_\be_\br_\bn/\b/_\bs_\bt_\br_\bi_\bn_\bg}
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br/\b//\b/_\bp_\ba_\bt_\bt_\be_\br_\bn/\b/_\bs_\bt_\br_\bi_\bn_\bg}
able expansion, arithmetic expansion, command and process sub-
stitution, and quote removal. The match is performed using the
rules described under P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below. In the first form
- above, only the first match is replaced. If there are two
+ above, only the first match is replaced. If there are two
slashes separating _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br and _\bp_\ba_\bt_\bt_\be_\br_\bn (the second form
- above), all matches of _\bp_\ba_\bt_\bt_\be_\br_\bn are replaced with _\bs_\bt_\br_\bi_\bn_\bg. If
- _\bp_\ba_\bt_\bt_\be_\br_\bn is preceded by #\b# (the third form above), it must match
+ above), all matches of _\bp_\ba_\bt_\bt_\be_\br_\bn are replaced with _\bs_\bt_\br_\bi_\bn_\bg. If
+ _\bp_\ba_\bt_\bt_\be_\br_\bn is preceded by #\b# (the third form above), it must match
at the beginning of the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. If _\bp_\ba_\bt_\bt_\be_\br_\bn
is preceded by %\b% (the fourth form above), it must match at the
end of the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. If the expansion of
null, matches of _\bp_\ba_\bt_\bt_\be_\br_\bn are deleted and the /\b/ following _\bp_\ba_\bt_\bt_\be_\br_\bn
may be omitted.
- If the p\bpa\bat\bts\bsu\bub\bb_\b_r\bre\bep\bpl\bla\bac\bce\bem\bme\ben\bnt\bt shell option is enabled using s\bsh\bho\bop\bpt\bt,
- any unquoted instances of &\b& in _\bs_\bt_\br_\bi_\bn_\bg are replaced with the
+ If the p\bpa\bat\bts\bsu\bub\bb_\b_r\bre\bep\bpl\bla\bac\bce\bem\bme\ben\bnt\bt shell option is enabled using s\bsh\bho\bop\bpt\bt,
+ any unquoted instances of &\b& in _\bs_\bt_\br_\bi_\bn_\bg are replaced with the
matching portion of _\bp_\ba_\bt_\bt_\be_\br_\bn.
Quoting any part of _\bs_\bt_\br_\bi_\bn_\bg inhibits replacement in the expansion
C\bCa\bas\bse\be m\bmo\bod\bdi\bif\bfi\bic\bca\bat\bti\bio\bon\bn. This expansion modifies the case of alpha-
betic characters in _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. The _\bp_\ba_\bt_\bt_\be_\br_\bn is expanded to pro-
duce a pattern just as in pathname expansion. Each character in
- the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is tested against _\bp_\ba_\bt_\bt_\be_\br_\bn, and,
- if it matches the pattern, its case is converted. The pattern
- should not attempt to match more than one character. The ^\b^ op-
+ the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is tested against _\bp_\ba_\bt_\bt_\be_\br_\bn, and,
+ if it matches the pattern, its case is converted. The pattern
+ should not attempt to match more than one character. The ^\b^ op-
erator converts lowercase letters matching _\bp_\ba_\bt_\bt_\be_\br_\bn to uppercase;
the ,\b, operator converts matching uppercase letters to lowercase.
- The ^\b^^\b^ and ,\b,,\b, expansions convert each matched character in the
- expanded value; the ^\b^ and ,\b, expansions match and convert only
- the first character in the expanded value. If _\bp_\ba_\bt_\bt_\be_\br_\bn is omit-
- ted, it is treated like a ?\b?, which matches every character. If
- _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the case modification operation is applied
- to each positional parameter in turn, and the expansion is the
- resultant list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array variable subscripted
- with @\b@ or *\b*, the case modification operation is applied to each
- member of the array in turn, and the expansion is the resultant
+ The ^\b^^\b^ and ,\b,,\b, expansions convert each matched character in the
+ expanded value; the ^\b^ and ,\b, expansions match and convert only
+ the first character in the expanded value. If _\bp_\ba_\bt_\bt_\be_\br_\bn is omit-
+ ted, it is treated like a ?\b?, which matches every character. If
+ _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the case modification operation is applied
+ to each positional parameter in turn, and the expansion is the
+ resultant list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array variable subscripted
+ with @\b@ or *\b*, the case modification operation is applied to each
+ member of the array in turn, and the expansion is the resultant
list.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br@\b@_\bo_\bp_\be_\br_\ba_\bt_\bo_\br}
u\bu The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
with the first character converted to uppercase, if it is
alphabetic.
- L\bL The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
- with uppercase alphabetic characters converted to lower-
+ L\bL The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
+ with uppercase alphabetic characters converted to lower-
case.
- Q\bQ The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
+ Q\bQ The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
quoted in a format that can be reused as input.
- E\bE The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
- with backslash escape sequences expanded as with the
- $\b$'\b'.\b..\b..\b.'\b' quoting mechanism.
+ E\bE The expansion is a string that is the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
+ with backslash escape sequences expanded as with the
+ $\b$'\b'...'\b' quoting mechanism.
P\bP The expansion is a string that is the result of expanding
the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br as if it were a prompt string (see
P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG below).
- A\bA The expansion is a string in the form of an assignment
- statement or d\bde\bec\bcl\bla\bar\bre\be command that, if evaluated, will
+ A\bA The expansion is a string in the form of an assignment
+ statement or d\bde\bec\bcl\bla\bar\bre\be command that, if evaluated, will
recreate _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br with its attributes and value.
- K\bK Produces a possibly-quoted version of the value of _\bp_\ba_\br_\ba_\bm_\b-
- _\be_\bt_\be_\br, except that it prints the values of indexed and as-
- sociative arrays as a sequence of quoted key-value pairs
- (see A\bAr\brr\bra\bay\bys\bs above).
- a\ba The expansion is a string consisting of flag values rep-
+ K\bK Produces a possibly-quoted version of the value of _\bp_\ba_\br_\ba_\b-
+ _\bm_\be_\bt_\be_\br, except that it prints the values of indexed and
+ associative arrays as a sequence of quoted key-value
+ pairs (see A\bAr\brr\bra\bay\bys\bs above).
+ a\ba The expansion is a string consisting of flag values rep-
resenting _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br's attributes.
- k\bk Like the K transformation, but expands the keys and val-
- ues of indexed and associative arrays to separate words
+ k\bk Like the K transformation, but expands the keys and val-
+ ues of indexed and associative arrays to separate words
after word splitting.
- If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the operation is applied to each posi-
- tional parameter in turn, and the expansion is the resultant
- list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array variable subscripted with @\b@ or
+ If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the operation is applied to each posi-
+ tional parameter in turn, and the expansion is the resultant
+ list. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array variable subscripted with @\b@ or
*\b*, the operation is applied to each member of the array in turn,
and the expansion is the resultant list.
tures its output, again with trailing newlines removed.
The character _\bc following the open brace must be a space, tab, newline,
- or |\b|, and the close brace must be in a position where a reserved word
- may appear (i.e., preceded by a command terminator such as semicolon).
+ or |\b|, and the close brace must be in a position where a reserved word
+ may appear (i.e., preceded by a command terminator such as semicolon).
B\bBa\bas\bsh\bh allows the close brace to be joined to the remaining characters in
the word without being followed by a shell metacharacter as a reserved
word would usually require.
Any side effects of _\bc_\bo_\bm_\bm_\ba_\bn_\bd take effect immediately in the current exe-
- cution environment and persist in the current environment after the
+ cution environment and persist in the current environment after the
command completes (e.g., the e\bex\bxi\bit\bt builtin will exit the shell).
- This type of command substitution superficially resembles executing an
- unnamed shell function: local variables are created as when a shell
- function is executing, and the r\bre\bet\btu\bur\brn\bn builtin forces _\bc_\bo_\bm_\bm_\ba_\bn_\bd to com-
- plete; however, the rest of the execution environment, including the
+ This type of command substitution superficially resembles executing an
+ unnamed shell function: local variables are created as when a shell
+ function is executing, and the r\bre\bet\btu\bur\brn\bn builtin forces _\bc_\bo_\bm_\bm_\ba_\bn_\bd to com-
+ plete; however, the rest of the execution environment, including the
positional parameters, is shared with the caller.
- If the first character following the open brace is a |\b|, the construct
- expands to the value of the R\bRE\bEP\bPL\bLY\bY shell variable after _\bc_\bo_\bm_\bm_\ba_\bn_\bd exe-
- cutes, without removing any trailing newlines, and the standard output
- of _\bc_\bo_\bm_\bm_\ba_\bn_\bd remains the same as in the calling shell. B\bBa\bas\bsh\bh creates R\bRE\bE-\b-
+ If the first character following the open brace is a |\b|, the construct
+ expands to the value of the R\bRE\bEP\bPL\bLY\bY shell variable after _\bc_\bo_\bm_\bm_\ba_\bn_\bd exe-
+ cutes, without removing any trailing newlines, and the standard output
+ of _\bc_\bo_\bm_\bm_\ba_\bn_\bd remains the same as in the calling shell. B\bBa\bas\bsh\bh creates R\bRE\bE-\b-
P\bPL\bLY\bY as an initially-unset local variable when _\bc_\bo_\bm_\bm_\ba_\bn_\bd executes, and re-
stores R\bRE\bEP\bPL\bLY\bY to the value it had before the command substitution after
_\bc_\bo_\bm_\bm_\ba_\bn_\bd completes, as with any local variable.
The _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn undergoes the same expansions as if it were within dou-
ble quotes, but double quote characters in _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn are not treated
- specially and are removed. All tokens in the expression undergo param-
- eter and variable expansion, command substitution, and quote removal.
+ specially and are removed. All tokens in the expression undergo para-
+ meter and variable expansion, command substitution, and quote removal.
The result is treated as the arithmetic expression to be evaluated.
Arithmetic expansions may be nested.
indicating failure and no substitution occurs.
P\bPr\bro\boc\bce\bes\bss\bs S\bSu\bub\bbs\bst\bti\bit\btu\but\bti\bio\bon\bn
- _\bP_\br_\bo_\bc_\be_\bs_\bs _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn allows a process's input or output to be referred
- to using a filename. It takes the form of <\b<(\b(_\bl_\bi_\bs_\bt)\b) or >\b>(\b(_\bl_\bi_\bs_\bt)\b). The
- process _\bl_\bi_\bs_\bt is run asynchronously, and its input or output appears as
+ _\bP_\br_\bo_\bc_\be_\bs_\bs _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn allows a process's input or output to be referred
+ to using a filename. It takes the form of <\b<(\b(_\bl_\bi_\bs_\bt)\b) or >\b>(\b(_\bl_\bi_\bs_\bt)\b). The
+ process _\bl_\bi_\bs_\bt is run asynchronously, and its input or output appears as
a filename. This filename is passed as an argument to the current com-
mand as the result of the expansion. If the >\b>(\b(_\bl_\bi_\bs_\bt)\b) form is used,
writing to the file will provide input for _\bl_\bi_\bs_\bt. If the <\b<(\b(_\bl_\bi_\bs_\bt)\b) form
output of _\bl_\bi_\bs_\bt. Process substitution is supported on systems that sup-
port named pipes (_\bF_\bI_\bF_\bO_\bs) or the /\b/d\bde\bev\bv/\b/f\bfd\bd method of naming open files.
- When available, process substitution is performed simultaneously with
- parameter and variable expansion, command substitution, and arithmetic
+ When available, process substitution is performed simultaneously with
+ parameter and variable expansion, command substitution, and arithmetic
expansion.
W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg
- The shell scans the results of parameter expansion, command substitu-
- tion, and arithmetic expansion that did not occur within double quotes
+ The shell scans the results of parameter expansion, command substitu-
+ tion, and arithmetic expansion that did not occur within double quotes
for _\bw_\bo_\br_\bd _\bs_\bp_\bl_\bi_\bt_\bt_\bi_\bn_\bg.
- The shell treats each character of I\bIF\bFS\bS as a delimiter, and splits the
- results of the other expansions into words using these characters as
+ The shell treats each character of I\bIF\bFS\bS as a delimiter, and splits the
+ results of the other expansions into words using these characters as
field terminators.
If I\bIF\bFS\bS is unset, or its value is exactly <\b<s\bsp\bpa\bac\bce\be>\b><\b<t\bta\bab\bb>\b><\b<n\bne\bew\bwl\bli\bin\bne\be>\b>, the de-
ter with no value is expanded within double quotes, a null argument re-
sults and is retained and passed to a command as an empty string. When
a quoted null argument appears as part of a word whose expansion is
- non-null, the null argument is removed. That is, the word -d'' becomes
- -d after word splitting and null argument removal.
+ non-null, the null argument is removed. That is, the word "-d''" be-
+ comes "-d" after word splitting and null argument removal.
Note that if no expansion occurs, no splitting is performed.
After word splitting, unless the -\b-f\bf option has been set, b\bba\bas\bsh\bh scans
each word for the characters *\b*, ?\b?, and [\b[. If one of these characters
appears, and is not quoted, then the word is regarded as a _\bp_\ba_\bt_\bt_\be_\br_\bn, and
- replaced with an alphabetically sorted list of filenames matching the
- pattern (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below). If no matching filenames are
- found, and the shell option n\bnu\bul\bll\blg\bgl\blo\bob\bb is not enabled, the word is left
- unchanged. If the n\bnu\bul\bll\blg\bgl\blo\bob\bb option is set, and no matches are found,
- the word is removed. If the f\bfa\bai\bil\blg\bgl\blo\bob\bb shell option is set, and no
- matches are found, an error message is printed and the command is not
+ replaced with an alphabetically sorted list of filenames matching the
+ pattern (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg below). If no matching filenames are
+ found, and the shell option n\bnu\bul\bll\blg\bgl\blo\bob\bb is not enabled, the word is left
+ unchanged. If the n\bnu\bul\bll\blg\bgl\blo\bob\bb option is set, and no matches are found,
+ the word is removed. If the f\bfa\bai\bil\blg\bgl\blo\bob\bb shell option is set, and no
+ matches are found, an error message is printed and the command is not
executed. If the shell option n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb is enabled, the match is per-
formed without regard to the case of alphabetic characters. When a
- pattern is used for pathname expansion, the character `\b``\b`.\b.'\b''\b' at the
- start of a name or immediately following a slash must be matched ex-
- plicitly, unless the shell option d\bdo\bot\btg\bgl\blo\bob\bb is set. In order to match
- the filenames `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b', the pattern must begin with ``.'' (for
- example, ``.?''), even if d\bdo\bot\btg\bgl\blo\bob\bb is set. If the g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs shell
- option is enabled, the filenames `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b' are never matched,
- even if the pattern begins with a `\b``\b`.\b.'\b''\b'. When not matching pathnames,
- the `\b``\b`.\b.'\b''\b' character is not treated specially. When matching a path-
- name, the slash character must always be matched explicitly by a slash
- in the pattern, but in other matching contexts it can be matched by a
- special pattern character as described below under P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg.
- See the description of s\bsh\bho\bop\bpt\bt below under S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS for a
- description of the n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb, n\bnu\bul\bll\blg\bgl\blo\bob\bb, g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs, f\bfa\bai\bil\blg\bgl\blo\bob\bb, and
- d\bdo\bot\btg\bgl\blo\bob\bb shell options.
-
- The G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE shell variable may be used to restrict the set of file
- names matching a _\bp_\ba_\bt_\bt_\be_\br_\bn. If G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is set, each matching file
- name that also matches one of the patterns in G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is removed
- from the list of matches. If the n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb option is set, the match-
- ing against the patterns in G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is performed without regard to
- case. The filenames `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b' are always ignored when G\bGL\bLO\bOB\bBI\bIG\bG-\b-
- N\bNO\bOR\bRE\bE is set and not null. However, setting G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE to a non-null
- value has the effect of enabling the d\bdo\bot\btg\bgl\blo\bob\bb shell option, so all other
- filenames beginning with a `\b``\b`.\b.'\b''\b' will match. To get the old behavior
- of ignoring filenames beginning with a `\b``\b`.\b.'\b''\b', make `\b``\b`.\b.*\b*'\b''\b' one of the
- patterns in G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE. The d\bdo\bot\btg\bgl\blo\bob\bb option is disabled when G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE
- is unset. The pattern matching honors the setting of the e\bex\bxt\btg\bgl\blo\bob\bb shell
- option.
-
- The G\bGL\bLO\bOB\bBS\bSO\bOR\bRT\bT variable controls how the results of pathname expansion
+ pattern is used for pathname expansion, the character "." at the start
+ of a name or immediately following a slash must be matched explicitly,
+ unless the shell option d\bdo\bot\btg\bgl\blo\bob\bb is set. In order to match the file-
+ names "." and "..", the pattern must begin with "." (for example,
+ ".?"), even if d\bdo\bot\btg\bgl\blo\bob\bb is set. If the g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs shell option is en-
+ abled, the filenames "." and ".." never match, even if the pattern be-
+ gins with a "." When not matching pathnames, the "." character is not
+ treated specially. When matching a pathname, the slash character must
+ always be matched explicitly by a slash in the pattern, but in other
+ matching contexts it can be matched by a special pattern character as
+ described below under P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg. See the description of s\bsh\bho\bop\bpt\bt
+ below under S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS for a description of the n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb,
+ n\bnu\bul\bll\blg\bgl\blo\bob\bb, g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs, f\bfa\bai\bil\blg\bgl\blo\bob\bb, and d\bdo\bot\btg\bgl\blo\bob\bb shell options.
+
+ The G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE shell variable may be used to restrict the set of file
+ names matching a _\bp_\ba_\bt_\bt_\be_\br_\bn. If G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is set, each matching file
+ name that also matches one of the patterns in G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is removed
+ from the list of matches. If the n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb option is set, the match-
+ ing against the patterns in G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is performed without regard to
+ case. The filenames "." and ".." are always ignored when G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is
+ set and not null. However, setting G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE to a non-null value has
+ the effect of enabling the d\bdo\bot\btg\bgl\blo\bob\bb shell option, so all other filenames
+ beginning with a Q . will match. To get the old behavior of ignoring
+ filenames beginning with a ".", make ".*" one of the patterns in G\bGL\bLO\bO-\b-
+ B\bBI\bIG\bGN\bNO\bOR\bRE\bE. The d\bdo\bot\btg\bgl\blo\bob\bb option is disabled when G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE is unset. The
+ pattern matching honors the setting of the e\bex\bxt\btg\bgl\blo\bob\bb shell option.
+
+ The G\bGL\bLO\bOB\bBS\bSO\bOR\bRT\bT variable controls how the results of pathname expansion
are sorted, as described above.
P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg
adjacent *\b*s will match only directories and subdirecto-
ries.
?\b? Matches any single character.
- [\b[.\b..\b..\b.]\b] Matches any one of the enclosed characters. A pair of
+ [\b[...]\b] Matches any one of the enclosed characters. A pair of
characters separated by a hyphen denotes a _\br_\ba_\bn_\bg_\be _\be_\bx_\bp_\br_\be_\bs_\b-
_\bs_\bi_\bo_\bn; any character that falls between those two charac-
ters, inclusive, using the current locale's collating se-
quence and character set, is matched. If the first char-
acter following the [\b[ is a !\b! or a ^\b^ then any character
not enclosed is matched. The sorting order of characters
- in range expressions, and the characters included in the
- range, are determined by the current locale and the val-
- ues of the L\bLC\bC_\b_C\bCO\bOL\bLL\bLA\bAT\bTE\bE or L\bLC\bC_\b_A\bAL\bLL\bL shell variables, if set.
+ in range expressions, and the characters included in the
+ range, are determined by the current locale and the val-
+ ues of the L\bLC\bC_\b_C\bCO\bOL\bLL\bLA\bAT\bTE\bE or L\bLC\bC_\b_A\bAL\bLL\bL shell variables, if set.
To obtain the traditional interpretation of range expres-
sions, where [\b[a\ba-\b-d\bd]\b] is equivalent to [\b[a\bab\bbc\bcd\bd]\b], set value of
the L\bLC\bC_\b_A\bAL\bLL\bL shell variable to C\bC, or enable the g\bgl\blo\bob\bba\bas\bsc\bci\bi-\b-
i\bir\bra\ban\bng\bge\bes\bs shell option. A -\b- may be matched by including it
- as the first or last character in the set. A ]\b] may be
- matched by including it as the first character in the
+ as the first or last character in the set. A ]\b] may be
+ matched by including it as the first character in the
set.
- Within [\b[ and ]\b], _\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br _\bc_\bl_\ba_\bs_\bs_\be_\bs can be specified using
+ Within [\b[ and ]\b], _\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br _\bc_\bl_\ba_\bs_\bs_\be_\bs can be specified using
the syntax [\b[:\b:_\bc_\bl_\ba_\bs_\bs:\b:]\b], where _\bc_\bl_\ba_\bs_\bs is one of the following
classes defined in the POSIX standard:
+
a\bal\bln\bnu\bum\bm a\bal\blp\bph\bha\ba a\bas\bsc\bci\bii\bi b\bbl\bla\ban\bnk\bk c\bcn\bnt\btr\brl\bl d\bdi\big\bgi\bit\bt g\bgr\bra\bap\bph\bh l\blo\bow\bwe\ber\br p\bpr\bri\bin\bnt\bt
p\bpu\bun\bnc\bct\bt s\bsp\bpa\bac\bce\be u\bup\bpp\bpe\ber\br w\bwo\bor\brd\bd x\bxd\bdi\big\bgi\bit\bt
+
A character class matches any character belonging to that
class. The w\bwo\bor\brd\bd character class matches letters, digits,
and the character _.
Within [\b[ and ]\b], an _\be_\bq_\bu_\bi_\bv_\ba_\bl_\be_\bn_\bc_\be _\bc_\bl_\ba_\bs_\bs can be specified us-
- ing the syntax [\b[=\b=_\bc=\b=]\b], which matches all characters with
- the same collation weight (as defined by the current lo-
+ ing the syntax [\b[=\b=_\bc=\b=]\b], which matches all characters with
+ the same collation weight (as defined by the current lo-
cale) as the character _\bc.
Within [\b[ and ]\b], the syntax [\b[.\b._\bs_\by_\bm_\bb_\bo_\bl.\b.]\b] matches the collat-
If the e\bex\bxt\btg\bgl\blo\bob\bb shell option is enabled using the s\bsh\bho\bop\bpt\bt builtin, the
shell recognizes several extended pattern matching operators. In the
following description, a _\bp_\ba_\bt_\bt_\be_\br_\bn_\b-_\bl_\bi_\bs_\bt is a list of one or more patterns
- separated by a |\b|. Composite patterns may be formed using one or more
+ separated by a |\b|. Composite patterns may be formed using one or more
of the following sub-patterns:
?\b?(\b(_\bp_\ba_\bt_\bt_\be_\br_\bn_\b-_\bl_\bi_\bs_\bt)\b)
terns, including shell functions and command substitutions.
When matching filenames, the d\bdo\bot\btg\bgl\blo\bob\bb shell option determines the set of
- filenames that are tested: when d\bdo\bot\btg\bgl\blo\bob\bb is enabled, the set of file-
- names includes all files beginning with ``.'', but ``.'' and ``..''
- must be matched by a pattern or sub-pattern that begins with a dot;
- when it is disabled, the set does not include any filenames beginning
- with ``.'' unless the pattern or sub-pattern begins with a ``.''. As
- above, ``.'' only has a special meaning when matching filenames.
+ filenames that are tested: when d\bdo\bot\btg\bgl\blo\bob\bb is enabled, the set of file-
+ names includes all files beginning with ".", but "." and ".." must be
+ matched by a pattern or sub-pattern that begins with a dot; when it is
+ disabled, the set does not include any filenames beginning with "." un-
+ less the pattern or sub-pattern begins with a ".". As above, "." only
+ has a special meaning when matching filenames.
Complicated extended pattern matching against long strings is slow, es-
pecially when the patterns contain alternations and the strings contain
Q\bQu\buo\bot\bte\be R\bRe\bem\bmo\bov\bva\bal\bl
After the preceding expansions, all unquoted occurrences of the charac-
- ters \\b\, '\b', and "\b" that did not result from one of the above expansions
+ ters \\b\, '\b', and "\b" that did not result from one of the above expansions
are removed.
R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN
- Before a command is executed, its input and output may be _\br_\be_\bd_\bi_\br_\be_\bc_\bt_\be_\bd
- using a special notation interpreted by the shell. _\bR_\be_\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn allows
- commands' file handles to be duplicated, opened, closed, made to refer
+ Before a command is executed, its input and output may be _\br_\be_\bd_\bi_\br_\be_\bc_\bt_\be_\bd
+ using a special notation interpreted by the shell. _\bR_\be_\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn allows
+ commands' file handles to be duplicated, opened, closed, made to refer
to different files, and can change the files the command reads from and
writes to. Redirection may also be used to modify file handles in the
current shell execution environment. The following redirection opera-
tors may precede or appear anywhere within a _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd or may fol-
- low a _\bc_\bo_\bm_\bm_\ba_\bn_\bd. Redirections are processed in the order they appear,
+ low a _\bc_\bo_\bm_\bm_\ba_\bn_\bd. Redirections are processed in the order they appear,
from left to right.
- Each redirection that may be preceded by a file descriptor number may
+ Each redirection that may be preceded by a file descriptor number may
instead be preceded by a word of the form {_\bv_\ba_\br_\bn_\ba_\bm_\be}. In this case, for
each redirection operator except >&- and <&-, the shell will allocate a
- file descriptor greater than or equal to 10 and assign it to _\bv_\ba_\br_\bn_\ba_\bm_\be.
- If >&- or <&- is preceded by {_\bv_\ba_\br_\bn_\ba_\bm_\be}, the value of _\bv_\ba_\br_\bn_\ba_\bm_\be defines
- the file descriptor to close. If {_\bv_\ba_\br_\bn_\ba_\bm_\be} is supplied, the redirect-
- ion persists beyond the scope of the command, allowing the shell pro-
+ file descriptor greater than or equal to 10 and assign it to _\bv_\ba_\br_\bn_\ba_\bm_\be.
+ If >&- or <&- is preceded by {_\bv_\ba_\br_\bn_\ba_\bm_\be}, the value of _\bv_\ba_\br_\bn_\ba_\bm_\be defines
+ the file descriptor to close. If {_\bv_\ba_\br_\bn_\ba_\bm_\be} is supplied, the redirec-
+ tion persists beyond the scope of the command, allowing the shell pro-
grammer to manage the file descriptor's lifetime manually. The
v\bva\bar\brr\bre\bed\bdi\bir\br_\b_c\bcl\blo\bos\bse\be shell option manages this behavior.
- In the following descriptions, if the file descriptor number is omit-
- ted, and the first character of the redirection operator is <\b<, the re-
- direction refers to the standard input (file descriptor 0). If the
- first character of the redirection operator is >\b>, the redirection
+ In the following descriptions, if the file descriptor number is omit-
+ ted, and the first character of the redirection operator is <\b<, the
+ redirection refers to the standard input (file descriptor 0). If the
+ first character of the redirection operator is >\b>, the redirection
refers to the standard output (file descriptor 1).
- The word following the redirection operator in the following descrip-
- tions, unless otherwise noted, is subjected to brace expansion, tilde
- expansion, parameter and variable expansion, command substitution,
- arithmetic expansion, quote removal, pathname expansion, and word
+ The word following the redirection operator in the following descrip-
+ tions, unless otherwise noted, is subjected to brace expansion, tilde
+ expansion, parameter and variable expansion, command substitution,
+ arithmetic expansion, quote removal, pathname expansion, and word
splitting. If it expands to more than one word, b\bba\bas\bsh\bh reports an error.
- Note that the order of redirections is significant. For example, the
+ Note that the order of redirections is significant. For example, the
command
ls >\b> dirlist 2>\b>&\b&1
- directs both standard output and standard error to the file _\bd_\bi_\br_\bl_\bi_\bs_\bt,
+ directs both standard output and standard error to the file _\bd_\bi_\br_\bl_\bi_\bs_\bt,
while the command
ls 2>\b>&\b&1 >\b> dirlist
- directs only the standard output to file _\bd_\bi_\br_\bl_\bi_\bs_\bt, because the standard
- error was duplicated from the standard output before the standard out-
+ directs only the standard output to file _\bd_\bi_\br_\bl_\bi_\bs_\bt, because the standard
+ error was duplicated from the standard output before the standard out-
put was redirected to _\bd_\bi_\br_\bl_\bi_\bs_\bt.
B\bBa\bas\bsh\bh handles several filenames specially when they are used in redirec-
File descriptor 2 is duplicated.
/\b/d\bde\bev\bv/\b/t\btc\bcp\bp/\b/_\bh_\bo_\bs_\bt/\b/_\bp_\bo_\br_\bt
If _\bh_\bo_\bs_\bt is a valid hostname or Internet address, and _\bp_\bo_\br_\bt
- is an integer port number or service name, b\bba\bas\bsh\bh attempts
+ is an integer port number or service name, b\bba\bas\bsh\bh attempts
to open the corresponding TCP socket.
/\b/d\bde\bev\bv/\b/u\bud\bdp\bp/\b/_\bh_\bo_\bs_\bt/\b/_\bp_\bo_\br_\bt
If _\bh_\bo_\bs_\bt is a valid hostname or Internet address, and _\bp_\bo_\br_\bt
R\bRe\bed\bdi\bir\bre\bec\bct\bti\bin\bng\bg I\bIn\bnp\bpu\but\bt
Redirection of input causes the file whose name results from the expan-
- sion of _\bw_\bo_\br_\bd to be opened for reading on file descriptor _\bn, or the
+ sion of _\bw_\bo_\br_\bd to be opened for reading on file descriptor _\bn, or the
standard input (file descriptor 0) if _\bn is not specified.
The general format for redirecting input is:
[_\bn]<\b<_\bw_\bo_\br_\bd
R\bRe\bed\bdi\bir\bre\bec\bct\bti\bin\bng\bg O\bOu\but\btp\bpu\but\bt
- Redirection of output causes the file whose name results from the ex-
- pansion of _\bw_\bo_\br_\bd to be opened for writing on file descriptor _\bn, or the
+ Redirection of output causes the file whose name results from the ex-
+ pansion of _\bw_\bo_\br_\bd to be opened for writing on file descriptor _\bn, or the
standard output (file descriptor 1) if _\bn is not specified. If the file
does not exist it is created; if it does exist it is truncated to zero
size.
builtin has been enabled, the redirection will fail if the file whose
name results from the expansion of _\bw_\bo_\br_\bd exists and is a regular file.
If the redirection operator is >\b>|\b|, or the redirection operator is >\b> and
- the n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br option to the s\bse\bet\bt builtin command is not enabled, the re-
- direction is attempted even if the file named by _\bw_\bo_\br_\bd exists.
+ the n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br option to the s\bse\bet\bt builtin command is not enabled, the
+ redirection is attempted even if the file named by _\bw_\bo_\br_\bd exists.
A\bAp\bpp\bpe\ben\bnd\bdi\bin\bng\bg R\bRe\bed\bdi\bir\bre\bec\bct\bte\bed\bd O\bOu\but\btp\bpu\but\bt
- Redirection of output in this fashion causes the file whose name re-
+ Redirection of output in this fashion causes the file whose name re-
sults from the expansion of _\bw_\bo_\br_\bd to be opened for appending on file de-
scriptor _\bn, or the standard output (file descriptor 1) if _\bn is not
specified. If the file does not exist it is created.
>\b>_\bw_\bo_\br_\bd 2>\b>&\b&1
- When using the second form, _\bw_\bo_\br_\bd may not expand to a number or -\b-. If
- it does, other redirection operators apply (see D\bDu\bup\bpl\bli\bic\bca\bat\bti\bin\bng\bg F\bFi\bil\ble\be D\bDe\be-\b-
+ When using the second form, _\bw_\bo_\br_\bd may not expand to a number or -\b-. If
+ it does, other redirection operators apply (see D\bDu\bup\bpl\bli\bic\bca\bat\bti\bin\bng\bg F\bFi\bil\ble\be D\bDe\be-\b-
s\bsc\bcr\bri\bip\bpt\bto\bor\brs\bs below) for compatibility reasons.
A\bAp\bpp\bpe\ben\bnd\bdi\bin\bng\bg S\bSt\bta\ban\bnd\bda\bar\brd\bd O\bOu\but\btp\bpu\but\bt a\ban\bnd\bd S\bSt\bta\ban\bnd\bda\bar\brd\bd E\bEr\brr\bro\bor\br
- This construct allows both the standard output (file descriptor 1) and
- the standard error output (file descriptor 2) to be appended to the
+ This construct allows both the standard output (file descriptor 1) and
+ the standard error output (file descriptor 2) to be appended to the
file whose name is the expansion of _\bw_\bo_\br_\bd.
The format for appending standard output and standard error is:
(see D\bDu\bup\bpl\bli\bic\bca\bat\bti\bin\bng\bg F\bFi\bil\ble\be D\bDe\bes\bsc\bcr\bri\bip\bpt\bto\bor\brs\bs below).
H\bHe\ber\bre\be D\bDo\boc\bcu\bum\bme\ben\bnt\bts\bs
- This type of redirection instructs the shell to read input from the
+ This type of redirection instructs the shell to read input from the
current source until it reads a line containing only _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br (with no
trailing blanks). All of the lines read up to that point are then used
- as the standard input (or file descriptor _\bn if _\bn is specified) for a
+ as the standard input (or file descriptor _\bn if _\bn is specified) for a
command.
The format of here-documents is:
_\bh_\be_\br_\be_\b-_\bd_\bo_\bc_\bu_\bm_\be_\bn_\bt
_\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br
- No parameter and variable expansion, command substitution, arithmetic
+ No parameter and variable expansion, command substitution, arithmetic
expansion, or pathname expansion is performed on _\bw_\bo_\br_\bd.
If any part of _\bw_\bo_\br_\bd is quoted, the _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br is the result of quote re-
moval on _\bw_\bo_\br_\bd, and the lines in the here-document are not expanded. If
- _\bw_\bo_\br_\bd is unquoted, the _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br is _\bw_\bo_\br_\bd itself, all lines of the here-
- document are subjected to parameter expansion, command substitution,
+ _\bw_\bo_\br_\bd is unquoted, the _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br is _\bw_\bo_\br_\bd itself, all lines of the here-
+ document are subjected to parameter expansion, command substitution,
and arithmetic expansion, the character sequence \\b\<\b<n\bne\bew\bwl\bli\bin\bne\be>\b> is ignored,
and \\b\ must be used to quote the characters \\b\, $\b$, and `\b`.
If the redirection operator is <\b<<\b<-\b-, then all leading tab characters are
- stripped from input lines and the line containing _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br. This al-
- lows here-documents within shell scripts to be indented in a natural
+ stripped from input lines and the line containing _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br. This al-
+ lows here-documents within shell scripts to be indented in a natural
fashion.
H\bHe\ber\bre\be S\bSt\btr\bri\bin\bng\bgs\bs
[_\bn]<\b<<\b<<\b<_\bw_\bo_\br_\bd
- The _\bw_\bo_\br_\bd undergoes tilde expansion, parameter and variable expansion,
- command substitution, arithmetic expansion, and quote removal. Path-
- name expansion and word splitting are not performed. The result is
+ The _\bw_\bo_\br_\bd undergoes tilde expansion, parameter and variable expansion,
+ command substitution, arithmetic expansion, and quote removal. Path-
+ name expansion and word splitting are not performed. The result is
supplied as a single string, with a newline appended, to the command on
its standard input (or file descriptor _\bn if _\bn is specified).
[_\bn]<\b<&\b&_\bw_\bo_\br_\bd
is used to duplicate input file descriptors. If _\bw_\bo_\br_\bd expands to one or
- more digits, the file descriptor denoted by _\bn is made to be a copy of
- that file descriptor. If the digits in _\bw_\bo_\br_\bd do not specify a file de-
+ more digits, the file descriptor denoted by _\bn is made to be a copy of
+ that file descriptor. If the digits in _\bw_\bo_\br_\bd do not specify a file de-
scriptor open for input, a redirection error occurs. If _\bw_\bo_\br_\bd evaluates
to -\b-, file descriptor _\bn is closed. If _\bn is not specified, the standard
input (file descriptor 0) is used.
[_\bn]>\b>&\b&_\bw_\bo_\br_\bd
- is used similarly to duplicate output file descriptors. If _\bn is not
- specified, the standard output (file descriptor 1) is used. If the
- digits in _\bw_\bo_\br_\bd do not specify a file descriptor open for output, a re-
- direction error occurs. If _\bw_\bo_\br_\bd evaluates to -\b-, file descriptor _\bn is
+ is used similarly to duplicate output file descriptors. If _\bn is not
+ specified, the standard output (file descriptor 1) is used. If the
+ digits in _\bw_\bo_\br_\bd do not specify a file descriptor open for output, a
+ redirection error occurs. If _\bw_\bo_\br_\bd evaluates to -\b-, file descriptor _\bn is
closed. As a special case, if _\bn is omitted, and _\bw_\bo_\br_\bd does not expand
to one or more digits or -\b-, the standard output and standard error are
redirected as described previously.
[_\bn]>\b>&\b&_\bd_\bi_\bg_\bi_\bt-\b-
- moves the file descriptor _\bd_\bi_\bg_\bi_\bt to file descriptor _\bn, or the standard
+ moves the file descriptor _\bd_\bi_\bg_\bi_\bt to file descriptor _\bn, or the standard
output (file descriptor 1) if _\bn is not specified.
O\bOp\bpe\ben\bni\bin\bng\bg F\bFi\bil\ble\be D\bDe\bes\bsc\bcr\bri\bip\bpt\bto\bor\brs\bs f\bfo\bor\br R\bRe\bea\bad\bdi\bin\bng\bg a\ban\bnd\bd W\bWr\bri\bit\bti\bin\bng\bg
[_\bn]<\b<>\b>_\bw_\bo_\br_\bd
- causes the file whose name is the expansion of _\bw_\bo_\br_\bd to be opened for
- both reading and writing on file descriptor _\bn, or on file descriptor 0
+ causes the file whose name is the expansion of _\bw_\bo_\br_\bd to be opened for
+ both reading and writing on file descriptor _\bn, or on file descriptor 0
if _\bn is not specified. If the file does not exist, it is created.
A\bAL\bLI\bIA\bAS\bSE\bES\bS
- _\bA_\bl_\bi_\ba_\bs_\be_\bs allow a string to be substituted for a word that is in a posi-
- tion in the input where it can be the first word of a simple command.
- Aliases have names and corresponding values that are set and unset us-
- ing the a\bal\bli\bia\bas\bs and u\bun\bna\bal\bli\bia\bas\bs builtin commands (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
+ _\bA_\bl_\bi_\ba_\bs_\be_\bs allow a string to be substituted for a word that is in a posi-
+ tion in the input where it can be the first word of a simple command.
+ Aliases have names and corresponding values that are set and unset us-
+ ing the a\bal\bli\bia\bas\bs and u\bun\bna\bal\bli\bia\bas\bs builtin commands (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
below).
- If the shell reads an unquoted word in the right position, it checks
- the word to see if it matches an alias name. If it matches, the shell
- replaces the word with the alias value, and reads that value as if it
+ If the shell reads an unquoted word in the right position, it checks
+ the word to see if it matches an alias name. If it matches, the shell
+ replaces the word with the alias value, and reads that value as if it
had been read instead of the word. The shell doesn't look at any char-
acters following the word before attempting alias substitution.
stores a series of commands for later execution. When the name of a
shell function is used as a simple command name, the list of commands
associated with that function name is executed. Functions are executed
- in the context of the current shell; no new process is created to in-
- terpret them (contrast this with the execution of a shell script).
- When a function is executed, the arguments to the function become the
+ in the context of the current shell; no new process is created to in-
+ terpret them (contrast this with the execution of a shell script).
+ When a function is executed, the arguments to the function become the
positional parameters during its execution. The special parameter #\b# is
updated to reflect the change. Special parameter 0\b0 is unchanged. The
first element of the F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE variable is set to the name of the func-
values are a result of the sequence of function calls that caused exe-
cution to reach the current function. The value of a variable that a
function sees depends on its value within its caller, if any, whether
- that caller is the "global" scope or another shell function. This is
- also the value that a local variable declaration "shadows", and the
- value that is restored when the function returns.
+ that caller is the global scope or another shell function. This is
+ also the value that a local variable declaration shadows, and the value
+ that is restored when the function returns.
- For example, if a variable _\bv_\ba_\br is declared as local in function _\bf_\bu_\bn_\bc_\b1,
- and _\bf_\bu_\bn_\bc_\b1 calls another function _\bf_\bu_\bn_\bc_\b2, references to _\bv_\ba_\br made from
+ For example, if a variable _\bv_\ba_\br is declared as local in function _\bf_\bu_\bn_\bc_\b1,
+ and _\bf_\bu_\bn_\bc_\b1 calls another function _\bf_\bu_\bn_\bc_\b2, references to _\bv_\ba_\br made from
within _\bf_\bu_\bn_\bc_\b2 will resolve to the local variable _\bv_\ba_\br from _\bf_\bu_\bn_\bc_\b1, shadow-
ing any global variable named _\bv_\ba_\br.
main so (appearing as unset) until it is reset in that scope or until
the function returns. Once the function returns, any instance of the
variable at a previous scope will become visible. If the unset acts on
- a variable at a previous scope, any instance of a variable with that
- name that had been shadowed will become visible (see below how the l\blo\bo-\b-
+ a variable at a previous scope, any instance of a variable with that
+ name that had been shadowed will become visible (see below how the l\blo\bo-\b-
c\bca\bal\blv\bva\bar\br_\b_u\bun\bns\bse\bet\bt shell option changes this behavior).
- The F\bFU\bUN\bNC\bCN\bNE\bES\bST\bT variable, if set to a numeric value greater than 0, de-
- fines a maximum function nesting level. Function invocations that ex-
+ The F\bFU\bUN\bNC\bCN\bNE\bES\bST\bT variable, if set to a numeric value greater than 0, de-
+ fines a maximum function nesting level. Function invocations that ex-
ceed the limit cause the entire command to abort.
- If the builtin command r\bre\bet\btu\bur\brn\bn is executed in a function, the function
- completes and execution resumes with the next command after the func-
+ If the builtin command r\bre\bet\btu\bur\brn\bn is executed in a function, the function
+ completes and execution resumes with the next command after the func-
tion call. Any command associated with the R\bRE\bET\bTU\bUR\bRN\bN trap is executed be-
fore execution resumes. When a function completes, the values of the
positional parameters and the special parameter #\b# are restored to the
Function names and definitions may be listed with the -\b-f\bf option to the
d\bde\bec\bcl\bla\bar\bre\be or t\bty\byp\bpe\bes\bse\bet\bt builtin commands. The -\b-F\bF option to d\bde\bec\bcl\bla\bar\bre\be or t\bty\byp\bpe\be-\b-
- s\bse\bet\bt will list the function names only (and optionally the source file
- and line number, if the e\bex\bxt\btd\bde\beb\bbu\bug\bg shell option is enabled). Functions
- may be exported so that child shell processes (those created when exe-
- cuting a separate shell invocation) automatically have them defined
+ s\bse\bet\bt will list the function names only (and optionally the source file
+ and line number, if the e\bex\bxt\btd\bde\beb\bbu\bug\bg shell option is enabled). Functions
+ may be exported so that child shell processes (those created when exe-
+ cuting a separate shell invocation) automatically have them defined
with the -\b-f\bf option to the e\bex\bxp\bpo\bor\brt\bt builtin. A function definition may be
deleted using the -\b-f\bf option to the u\bun\bns\bse\bet\bt builtin.
Functions may be recursive. The F\bFU\bUN\bNC\bCN\bNE\bES\bST\bT variable may be used to limit
- the depth of the function call stack and restrict the number of func-
+ the depth of the function call stack and restrict the number of func-
tion invocations. By default, no limit is imposed on the number of re-
cursive calls.
The shell allows arithmetic expressions to be evaluated, under certain
circumstances (see the l\ble\bet\bt and d\bde\bec\bcl\bla\bar\bre\be builtin commands, the (\b((\b( com-
pound command, and A\bAr\bri\bit\bth\bhm\bme\bet\bti\bic\bc E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn). Evaluation is done in fixed-
- width integers with no check for overflow, though division by 0 is
- trapped and flagged as an error. The operators and their precedence,
- associativity, and values are the same as in the C language. The fol-
+ width integers with no check for overflow, though division by 0 is
+ trapped and flagged as an error. The operators and their precedence,
+ associativity, and values are the same as in the C language. The fol-
lowing list of operators is grouped into levels of equal-precedence op-
erators. The levels are listed in order of decreasing precedence.
Shell variables are allowed as operands; parameter expansion is per-
formed before the expression is evaluated. Within an expression, shell
- variables may also be referenced by name without using the parameter
- expansion syntax. A shell variable that is null or unset evaluates to
+ variables may also be referenced by name without using the parameter
+ expansion syntax. A shell variable that is null or unset evaluates to
0 when referenced by name without using the parameter expansion syntax.
The value of a variable is evaluated as an arithmetic expression when
it is referenced, or when a variable which has been given the _\bi_\bn_\bt_\be_\bg_\be_\br
attribute using d\bde\bec\bcl\bla\bar\bre\be -\b-i\bi is assigned a value. A null value evaluates
- to 0. A shell variable need not have its _\bi_\bn_\bt_\be_\bg_\be_\br attribute turned on
+ to 0. A shell variable need not have its _\bi_\bn_\bt_\be_\bg_\be_\br attribute turned on
to be used in an expression.
Integer constants follow the C language definition, without suffixes or
character constants. Constants with a leading 0 are interpreted as oc-
- tal numbers. A leading 0x or 0X denotes hexadecimal. Otherwise, num-
- bers take the form [_\bb_\ba_\bs_\be_\b#]n, where the optional _\bb_\ba_\bs_\be is a decimal num-
- ber between 2 and 64 representing the arithmetic base, and _\bn is a num-
- ber in that base. If _\bb_\ba_\bs_\be_\b# is omitted, then base 10 is used. When
+ tal numbers. A leading 0x or 0X denotes hexadecimal. Otherwise, num-
+ bers take the form [_\bb_\ba_\bs_\be_\b#]n, where the optional _\bb_\ba_\bs_\be is a decimal num-
+ ber between 2 and 64 representing the arithmetic base, and _\bn is a num-
+ ber in that base. If _\bb_\ba_\bs_\be_\b# is omitted, then base 10 is used. When
specifying _\bn, if a non-digit is required, the digits greater than 9 are
represented by the lowercase letters, the uppercase letters, @, and _,
in that order. If _\bb_\ba_\bs_\be is less than or equal to 36, lowercase and up-
Expressions are formed from the following unary or binary primaries.
B\bBa\bas\bsh\bh handles several filenames specially when they are used in expres-
sions. If the operating system on which b\bba\bas\bsh\bh is running provides these
- special files, bash will use them; otherwise it will emulate them in-
- ternally with this behavior: If any _\bf_\bi_\bl_\be argument to one of the pri-
+ special files, bash will use them; otherwise it will emulate them in-
+ ternally with this behavior: If any _\bf_\bi_\bl_\be argument to one of the pri-
maries is of the form _\b/_\bd_\be_\bv_\b/_\bf_\bd_\b/_\bn, then file descriptor _\bn is checked. If
the _\bf_\bi_\bl_\be argument to one of the primaries is one of _\b/_\bd_\be_\bv_\b/_\bs_\bt_\bd_\bi_\bn,
_\b/_\bd_\be_\bv_\b/_\bs_\bt_\bd_\bo_\bu_\bt, or _\b/_\bd_\be_\bv_\b/_\bs_\bt_\bd_\be_\br_\br, file descriptor 0, 1, or 2, respectively,
-\b-h\bh _\bf_\bi_\bl_\be
True if _\bf_\bi_\bl_\be exists and is a symbolic link.
-\b-k\bk _\bf_\bi_\bl_\be
- True if _\bf_\bi_\bl_\be exists and its ``sticky'' bit is set.
+ True if _\bf_\bi_\bl_\be exists and its "sticky" bit is set.
-\b-p\bp _\bf_\bi_\bl_\be
True if _\bf_\bi_\bl_\be exists and is a named pipe (FIFO).
-\b-r\br _\bf_\bi_\bl_\be
value). If _\bv_\ba_\br_\bn_\ba_\bm_\be is an indexed array variable name sub-
scripted by _\b@ or _\b*, this returns true if the array has any set
elements. If _\bv_\ba_\br_\bn_\ba_\bm_\be is an associative array variable name sub-
- scripted by _\b@ or _\b*, this returns true if an element with that
+ scripted by _\b@ or _\b*, this returns true if an element with that
key is set.
-\b-R\bR _\bv_\ba_\br_\bn_\ba_\bm_\be
- True if the shell variable _\bv_\ba_\br_\bn_\ba_\bm_\be is set and is a name refer-
+ True if the shell variable _\bv_\ba_\br_\bn_\ba_\bm_\be is set and is a name refer-
ence.
-\b-z\bz _\bs_\bt_\br_\bi_\bn_\bg
True if the length of _\bs_\bt_\br_\bi_\bn_\bg is zero.
_\bs_\bt_\br_\bi_\bn_\bg_\b1 =\b==\b= _\bs_\bt_\br_\bi_\bn_\bg_\b2
_\bs_\bt_\br_\bi_\bn_\bg_\b1 =\b= _\bs_\bt_\br_\bi_\bn_\bg_\b2
- True if the strings are equal. =\b= should be used with the t\bte\bes\bst\bt
- command for POSIX conformance. When used with the [\b[[\b[ command,
+ True if the strings are equal. =\b= should be used with the t\bte\bes\bst\bt
+ command for POSIX conformance. When used with the [\b[[\b[ command,
this performs pattern matching as described above (C\bCo\bom\bmp\bpo\bou\bun\bnd\bd C\bCo\bom\bm-\b-
m\bma\ban\bnd\bds\bs).
S\bSI\bIM\bMP\bPL\bLE\bE C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN
When a simple command is executed, the shell performs the following ex-
- pansions, assignments, and redirections, from left to right, in the
+ pansions, assignments, and redirections, from left to right, in the
following order.
- 1. The words that the parser has marked as variable assignments
- (those preceding the command name) and redirections are saved
+ 1. The words that the parser has marked as variable assignments
+ (those preceding the command name) and redirections are saved
for later processing.
- 2. The words that are not variable assignments or redirections are
- expanded. If any words remain after expansion, the first word
- is taken to be the name of the command and the remaining words
+ 2. The words that are not variable assignments or redirections are
+ expanded. If any words remain after expansion, the first word
+ is taken to be the name of the command and the remaining words
are the arguments.
3. Redirections are performed as described above under R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN.
4. The text after the =\b= in each variable assignment undergoes tilde
expansion, parameter expansion, command substitution, arithmetic
- expansion, and quote removal before being assigned to the vari-
+ expansion, and quote removal before being assigned to the vari-
able.
If no command name results, the variable assignments affect the current
are performed before redirections. Otherwise, the variables are added
to the environment of the executed command and do not affect the cur-
rent shell environment. If any of the assignments attempts to assign a
- value to a readonly variable, an error occurs, and the command exits
+ value to a readonly variable, an error occurs, and the command exits
with a non-zero status.
- If no command name results, redirections are performed, but do not af-
- fect the current shell environment. A redirection error causes the
+ If no command name results, redirections are performed, but do not af-
+ fect the current shell environment. A redirection error causes the
command to exit with a non-zero status.
- If there is a command name left after expansion, execution proceeds as
- described below. Otherwise, the command exits. If one of the expan-
- sions contained a command substitution, the exit status of the command
- is the exit status of the last command substitution performed. If
+ If there is a command name left after expansion, execution proceeds as
+ described below. Otherwise, the command exits. If one of the expan-
+ sions contained a command substitution, the exit status of the command
+ is the exit status of the last command substitution performed. If
there were no command substitutions, the command exits with a status of
zero.
If the name is neither a shell function nor a builtin, and contains no
slashes, b\bba\bas\bsh\bh searches each element of the P\bPA\bAT\bTH\bH for a directory con-
taining an executable file by that name. B\bBa\bas\bsh\bh uses a hash table to re-
- member the full pathnames of executable files (see h\bha\bas\bsh\bh under S\bSH\bHE\bEL\bLL\bL
- B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below). A full search of the directories in P\bPA\bAT\bTH\bH is
- performed only if the command is not found in the hash table. If the
+ member the full pathnames of executable files (see h\bha\bas\bsh\bh under S\bSH\bHE\bEL\bLL\bL
+ B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below). A full search of the directories in P\bPA\bAT\bTH\bH is
+ performed only if the command is not found in the hash table. If the
search is unsuccessful, the shell searches for a defined shell function
named c\bco\bom\bmm\bma\ban\bnd\bd_\b_n\bno\bot\bt_\b_f\bfo\bou\bun\bnd\bd_\b_h\bha\ban\bnd\bdl\ble\be. If that function exists, it is invoked
- in a separate execution environment with the original command and the
- original command's arguments as its arguments, and the function's exit
- status becomes the exit status of that subshell. If that function is
+ in a separate execution environment with the original command and the
+ original command's arguments as its arguments, and the function's exit
+ status becomes the exit status of that subshell. If that function is
not defined, the shell prints an error message and returns an exit sta-
tus of 127.
If this execution fails because the file is not in executable format,
and the file is not a directory, it is assumed to be a _\bs_\bh_\be_\bl_\bl _\bs_\bc_\br_\bi_\bp_\bt, a
file containing shell commands, and the shell creates a new instance of
- itself to execute it. This subshell reinitializes itself, so that the
+ itself to execute it. This subshell reinitializes itself, so that the
effect is as if a new shell had been invoked to handle the script, with
the exception that the locations of commands remembered by the parent
(see h\bha\bas\bsh\bh below under S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS) are retained by the
+\bo shell parameters that are set by variable assignment or with s\bse\bet\bt
or inherited from the shell's parent in the environment
- +\bo shell functions defined during execution or inherited from the
+ +\bo shell functions defined during execution or inherited from the
shell's parent in the environment
- +\bo options enabled at invocation (either by default or with com-
+ +\bo options enabled at invocation (either by default or with com-
mand-line arguments) or by s\bse\bet\bt
+\bo options enabled by s\bsh\bho\bop\bpt\bt
+\bo shell aliases defined with a\bal\bli\bia\bas\bs
- +\bo various process IDs, including those of background jobs, the
+ +\bo various process IDs, including those of background jobs, the
value of $\b$$\b$, and the value of P\bPP\bPI\bID\bD
- When a simple command other than a builtin or shell function is to be
- executed, it is invoked in a separate execution environment that con-
- sists of the following. Unless otherwise noted, the values are inher-
+ When a simple command other than a builtin or shell function is to be
+ executed, it is invoked in a separate execution environment that con-
+ sists of the following. Unless otherwise noted, the values are inher-
ited from the shell.
-
- +\bo the shell's open files, plus any modifications and additions
+ +\bo the shell's open files, plus any modifications and additions
specified by redirections to the command
+\bo the current working directory
+\bo the file creation mode mask
- +\bo shell variables and functions marked for export, along with
+ +\bo shell variables and functions marked for export, along with
variables exported for the command, passed in the environment
+\bo traps caught by the shell are reset to the values inherited from
executed in a subshell environment. Changes made to the subshell envi-
ronment cannot affect the shell's execution environment.
- Subshells spawned to execute command substitutions inherit the value of
- the -\b-e\be option from the parent shell. When not in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, b\bba\bas\bsh\bh
- clears the -\b-e\be option in such subshells.
+ When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, subshells spawned to execute command
+ substitutions inherit the value of the -\b-e\be option from their parent
+ shell. When not in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, b\bba\bas\bsh\bh clears the -\b-e\be option in such sub-
+ shells. See the description of the i\bin\bnh\bhe\ber\bri\bit\bt_\b_e\ber\brr\bre\bex\bxi\bit\bt shell option below
+ for how to control this behavior when not in posix mode.
If a command is followed by a &\b& and job control is not active, the de-
fault standard input for the command is the empty file _\b/_\bd_\be_\bv_\b/_\bn_\bu_\bl_\bl. Oth-
- erwise, the invoked command inherits the file descriptors of the call-
+ erwise, the invoked command inherits the file descriptors of the call-
ing shell as modified by redirections.
E\bEN\bNV\bVI\bIR\bRO\bON\bNM\bME\bEN\bNT\bT
- When a program is invoked it is given an array of strings called the
+ When a program is invoked it is given an array of strings called the
_\be_\bn_\bv_\bi_\br_\bo_\bn_\bm_\be_\bn_\bt. This is a list of _\bn_\ba_\bm_\be-_\bv_\ba_\bl_\bu_\be pairs, of the form
_\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be.
- The shell provides several ways to manipulate the environment. On in-
- vocation, the shell scans its own environment and creates a parameter
- for each name found, automatically marking it for _\be_\bx_\bp_\bo_\br_\bt to child pro-
- cesses. Executed commands inherit the environment. The e\bex\bxp\bpo\bor\brt\bt and d\bde\be-\b-
- c\bcl\bla\bar\bre\be -\b-x\bx commands allow parameters and functions to be added to and
+ The shell provides several ways to manipulate the environment. On in-
+ vocation, the shell scans its own environment and creates a parameter
+ for each name found, automatically marking it for _\be_\bx_\bp_\bo_\br_\bt to child
+ processes. Executed commands inherit the environment. The e\bex\bxp\bpo\bor\brt\bt and
+ d\bde\bec\bcl\bla\bar\bre\be -\b-x\bx commands allow parameters and functions to be added to and
deleted from the environment. If the value of a parameter in the envi-
ronment is modified, the new value becomes part of the environment, re-
- placing the old. The environment inherited by any executed command
- consists of the shell's initial environment, whose values may be modi-
- fied in the shell, less any pairs removed by the u\bun\bns\bse\bet\bt command, plus
+ placing the old. The environment inherited by any executed command
+ consists of the shell's initial environment, whose values may be modi-
+ fied in the shell, less any pairs removed by the u\bun\bns\bse\bet\bt command, plus
any additions via the e\bex\bxp\bpo\bor\brt\bt and d\bde\bec\bcl\bla\bar\bre\be -\b-x\bx commands.
- The environment for any _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd or function may be augmented
- temporarily by prefixing it with parameter assignments, as described
+ The environment for any _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd or function may be augmented
+ temporarily by prefixing it with parameter assignments, as described
above in P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS. These assignment statements affect only the envi-
ronment seen by that command.
ment.
E\bEX\bXI\bIT\bT S\bST\bTA\bAT\bTU\bUS\bS
- The exit status of an executed command is the value returned by the
+ The exit status of an executed command is the value returned by the
_\bw_\ba_\bi_\bt_\bp_\bi_\bd system call or equivalent function. Exit statuses fall between
0 and 255, though, as explained below, the shell may use values above
125 specially. Exit statuses from shell builtins and compound commands
will use special values to indicate specific failure modes.
For the shell's purposes, a command which exits with a zero exit status
- has succeeded. An exit status of zero indicates success. A non-zero
- exit status indicates failure. When a command terminates on a fatal
+ has succeeded. An exit status of zero indicates success. A non-zero
+ exit status indicates failure. When a command terminates on a fatal
signal _\bN, b\bba\bas\bsh\bh uses the value of 128+_\bN as the exit status.
- If a command is not found, the child process created to execute it re-
- turns a status of 127. If a command is found but is not executable,
+ If a command is not found, the child process created to execute it re-
+ turns a status of 127. If a command is found but is not executable,
the return status is 126.
If a command fails because of an error during expansion or redirection,
The exit status of the last command is available in the special parame-
ter $?.
- B\bBa\bas\bsh\bh itself returns the exit status of the last command executed, un-
- less a syntax error occurs, in which case it exits with a non-zero
+ B\bBa\bas\bsh\bh itself returns the exit status of the last command executed, un-
+ less a syntax error occurs, in which case it exits with a non-zero
value. See also the e\bex\bxi\bit\bt builtin command below.
S\bSI\bIG\bGN\bNA\bAL\bLS\bS
- When b\bba\bas\bsh\bh is interactive, in the absence of any traps, it ignores
+ When b\bba\bas\bsh\bh is interactive, in the absence of any traps, it ignores
S\bSI\bIG\bGT\bTE\bER\bRM\bM (so that k\bki\bil\bll\bl 0\b0 does not kill an interactive shell), and S\bSI\bIG\bGI\bIN\bNT\bT
is caught and handled (so that the w\bwa\bai\bit\bt builtin is interruptible). In
all cases, b\bba\bas\bsh\bh ignores S\bSI\bIG\bGQ\bQU\bUI\bIT\bT. If job control is in effect, b\bba\bas\bsh\bh ig-
Non-builtin commands run by b\bba\bas\bsh\bh have signal handlers set to the values
inherited by the shell from its parent. When job control is not in ef-
- fect, asynchronous commands ignore S\bSI\bIG\bGI\bIN\bNT\bT and S\bSI\bIG\bGQ\bQU\bUI\bIT\bT in addition to
- these inherited handlers. Commands run as a result of command substi-
+ fect, asynchronous commands ignore S\bSI\bIG\bGI\bIN\bNT\bT and S\bSI\bIG\bGQ\bQU\bUI\bIT\bT in addition to
+ these inherited handlers. Commands run as a result of command substi-
tution ignore the keyboard-generated job control signals S\bSI\bIG\bGT\bTT\bTI\bIN\bN, S\bSI\bIG\bGT\bT-\b-
T\bTO\bOU\bU, and S\bSI\bIG\bGT\bTS\bST\bTP\bP.
The shell exits by default upon receipt of a S\bSI\bIG\bGH\bHU\bUP\bP. Before exiting,
an interactive shell resends the S\bSI\bIG\bGH\bHU\bUP\bP to all jobs, running or
stopped. Stopped jobs are sent S\bSI\bIG\bGC\bCO\bON\bNT\bT to ensure that they receive the
- S\bSI\bIG\bGH\bHU\bUP\bP. To prevent the shell from sending the signal to a particular
- job, it should be removed from the jobs table with the d\bdi\bis\bso\bow\bwn\bn builtin
- (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below) or marked to not receive S\bSI\bIG\bGH\bHU\bUP\bP us-
+ S\bSI\bIG\bGH\bHU\bUP\bP. To prevent the shell from sending the signal to a particular
+ job, it should be removed from the jobs table with the d\bdi\bis\bso\bow\bwn\bn builtin
+ (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below) or marked to not receive S\bSI\bIG\bGH\bHU\bUP\bP us-
ing d\bdi\bis\bso\bow\bwn\bn -\b-h\bh.
- If the h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt shell option has been set with s\bsh\bho\bop\bpt\bt, b\bba\bas\bsh\bh sends a
+ If the h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt shell option has been set with s\bsh\bho\bop\bpt\bt, b\bba\bas\bsh\bh sends a
S\bSI\bIG\bGH\bHU\bUP\bP to all jobs when an interactive login shell exits.
- If b\bba\bas\bsh\bh is waiting for a command to complete and receives a signal for
+ If b\bba\bas\bsh\bh is waiting for a command to complete and receives a signal for
which a trap has been set, the trap will not be executed until the com-
mand completes. When b\bba\bas\bsh\bh is waiting for an asynchronous command via
the w\bwa\bai\bit\bt builtin, the reception of a signal for which a trap has been
set will cause the w\bwa\bai\bit\bt builtin to return immediately with an exit sta-
tus greater than 128, immediately after which the trap is executed.
- When job control is not enabled, and b\bba\bas\bsh\bh is waiting for a foreground
+ When job control is not enabled, and b\bba\bas\bsh\bh is waiting for a foreground
command to complete, the shell receives keyboard-generated signals such
as S\bSI\bIG\bGI\bIN\bNT\bT (usually generated by ^\b^C\bC) that users commonly intend to send
to that command. This happens because the shell and the command are in
- the same process group as the terminal, and ^\b^C\bC sends S\bSI\bIG\bGI\bIN\bNT\bT to all pro-
- cesses in that process group.
+ the same process group as the terminal, and ^\b^C\bC sends S\bSI\bIG\bGI\bIN\bNT\bT to all
+ processes in that process group.
- When b\bba\bas\bsh\bh is running without job control enabled and receives S\bSI\bIG\bGI\bIN\bNT\bT
- while waiting for a foreground command, it waits until that foreground
+ When b\bba\bas\bsh\bh is running without job control enabled and receives S\bSI\bIG\bGI\bIN\bNT\bT
+ while waiting for a foreground command, it waits until that foreground
command terminates and then decides what to do about the S\bSI\bIG\bGI\bIN\bNT\bT:
1. If the command terminates due to the S\bSI\bIG\bGI\bIN\bNT\bT, b\bba\bas\bsh\bh concludes that
nal, either, instead assuming that the S\bSI\bIG\bGI\bIN\bNT\bT was used as part
of the program's normal operation (e.g., emacs uses it to abort
editing commands) or deliberately discarded. However, b\bba\bas\bsh\bh will
- run any trap set on S\bSI\bIG\bGI\bIN\bNT\bT, as it does with any other trapped
- signal it receives while it is waiting for the foreground com-
+ run any trap set on S\bSI\bIG\bGI\bIN\bNT\bT, as it does with any other trapped
+ signal it receives while it is waiting for the foreground com-
mand to complete, for compatibility.
J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL
_\bJ_\bo_\bb _\bc_\bo_\bn_\bt_\br_\bo_\bl refers to the ability to selectively stop (_\bs_\bu_\bs_\bp_\be_\bn_\bd) the ex-
ecution of processes and continue (_\br_\be_\bs_\bu_\bm_\be) their execution at a later
point. A user typically employs this facility via an interactive in-
- terface supplied jointly by the operating system kernel's terminal
- driver and b\bba\bas\bsh\bh.
+ terface supplied jointly by the operating system kernel's terminal dri-
+ ver and b\bba\bas\bsh\bh.
- The shell associates a _\bj_\bo_\bb with each pipeline. It keeps a table of
- currently executing jobs, which may be listed with the j\bjo\bob\bbs\bs command.
- When b\bba\bas\bsh\bh starts a job asynchronously (in the _\bb_\ba_\bc_\bk_\bg_\br_\bo_\bu_\bn_\bd), it prints a
+ The shell associates a _\bj_\bo_\bb with each pipeline. It keeps a table of
+ currently executing jobs, which may be listed with the j\bjo\bob\bbs\bs command.
+ When b\bba\bas\bsh\bh starts a job asynchronously (in the _\bb_\ba_\bc_\bk_\bg_\br_\bo_\bu_\bn_\bd), it prints a
line that looks like:
[1] 25647
indicating that this job is job number 1 and that the process ID of the
last process in the pipeline associated with this job is 25647. All of
- the processes in a single pipeline are members of the same job. B\bBa\bas\bsh\bh
+ the processes in a single pipeline are members of the same job. B\bBa\bas\bsh\bh
uses the _\bj_\bo_\bb abstraction as the basis for job control.
- To facilitate the implementation of the user interface to job control,
+ To facilitate the implementation of the user interface to job control,
the operating system maintains the notion of a _\bc_\bu_\br_\br_\be_\bn_\bt _\bt_\be_\br_\bm_\bi_\bn_\ba_\bl _\bp_\br_\bo_\bc_\be_\bs_\bs
_\bg_\br_\bo_\bu_\bp _\bI_\bD. Members of this process group (processes whose process group
ID is equal to the current terminal process group ID) receive keyboard-
the _\bf_\bo_\br_\be_\bg_\br_\bo_\bu_\bn_\bd. _\bB_\ba_\bc_\bk_\bg_\br_\bo_\bu_\bn_\bd processes are those whose process group ID
differs from the terminal's; such processes are immune to keyboard-gen-
erated signals. Only foreground processes are allowed to read from or,
- if the user so specifies with stty tostop, write to the terminal.
- Background processes which attempt to read from (write to when stty
- tostop is in effect) the terminal are sent a S\bSI\bIG\bGT\bTT\bTI\bIN\bN (\b(S\bSI\bIG\bGT\bTT\bTO\bOU\bU)\b) signal
- by the kernel's terminal driver, which, unless caught, suspends the
- process.
+ if the user so specifies with "stty tostop", write to the terminal.
+ Background processes which attempt to read from (write to when "tostop"
+ is in effect) the terminal are sent a S\bSI\bIG\bGT\bTT\bTI\bIN\bN (\b(S\bSI\bIG\bGT\bTT\bTO\bOU\bU)\b) signal by the
+ kernel's terminal driver, which, unless caught, suspends the process.
If the operating system on which b\bba\bas\bsh\bh is running supports job control,
b\bba\bas\bsh\bh contains facilities to use it. Typing the _\bs_\bu_\bs_\bp_\be_\bn_\bd character (typ-
be stopped and returns control to b\bba\bas\bsh\bh. Typing the _\bd_\be_\bl_\ba_\by_\be_\bd _\bs_\bu_\bs_\bp_\be_\bn_\bd
character (typically ^\b^Y\bY, Control-Y) causes the process to be stopped
when it attempts to read input from the terminal, and control to be re-
- turned to b\bba\bas\bsh\bh. The user may then manipulate the state of this job,
- using the b\bbg\bg command to continue it in the background, the f\bfg\bg command
+ turned to b\bba\bas\bsh\bh. The user may then manipulate the state of this job,
+ using the b\bbg\bg command to continue it in the background, the f\bfg\bg command
to continue it in the foreground, or the k\bki\bil\bll\bl command to kill it. A ^\b^Z\bZ
takes effect immediately, and has the additional side effect of causing
pending output and typeahead to be discarded.
line. For example, %\b%c\bce\be refers to a stopped job whose command name be-
gins with c\bce\be. If a prefix matches more than one job, b\bba\bas\bsh\bh reports an
error. Using %\b%?\b?c\bce\be, on the other hand, refers to any job containing the
- string c\bce\be in its command line. If the substring matches more than one
+ string c\bce\be in its command line. If the substring matches more than one
job, b\bba\bas\bsh\bh reports an error. The symbols %\b%%\b% and %\b%+\b+ refer to the shell's
notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb, which is the last job stopped while it was
in the foreground or started in the background. The _\bp_\br_\be_\bv_\bi_\bo_\bu_\bs _\bj_\bo_\bb may
job specification) also refers to the current job.
Simply naming a job can be used to bring it into the foreground: %\b%1\b1 is
- a synonym for `\b``\b`f\bfg\bg %\b%1\b1'\b''\b', bringing job 1 from the background into the
- foreground. Similarly, `\b``\b`%\b%1\b1 &\b&'\b''\b' resumes job 1 in the background,
- equivalent to `\b``\b`b\bbg\bg %\b%1\b1'\b''\b'.
+ a synonym for "fg %1", bringing job 1 from the background into the
+ foreground. Similarly, "%1 &" resumes job 1 in the background, equiva-
+ lent to "bg %1".
- The shell learns immediately whenever a job changes state. Normally,
+ The shell learns immediately whenever a job changes state. Normally,
b\bba\bas\bsh\bh waits until it is about to print a prompt before reporting changes
in a job's status so as to not interrupt any other output. If the -\b-b\bb
option to the s\bse\bet\bt builtin command is enabled, b\bba\bas\bsh\bh reports such changes
- immediately. Any trap on S\bSI\bIG\bGC\bCH\bHL\bLD\bD is executed for each child that ex-
+ immediately. Any trap on S\bSI\bIG\bGC\bCH\bHL\bLD\bD is executed for each child that ex-
its.
- If an attempt to exit b\bba\bas\bsh\bh is made while jobs are stopped (or, if the
- c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs shell option has been enabled using the s\bsh\bho\bop\bpt\bt builtin, run-
+ If an attempt to exit b\bba\bas\bsh\bh is made while jobs are stopped (or, if the
+ c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs shell option has been enabled using the s\bsh\bho\bop\bpt\bt builtin, run-
ning), the shell prints a warning message, and, if the c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs option
is enabled, lists the jobs and their statuses. The j\bjo\bob\bbs\bs command may
then be used to inspect their status. If a second attempt to exit is
P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG
When executing interactively, b\bba\bas\bsh\bh displays the primary prompt P\bPS\bS1\b1 when
- it is ready to read a command, and the secondary prompt P\bPS\bS2\b2 when it
- needs more input to complete a command. B\bBa\bas\bsh\bh displays P\bPS\bS0\b0 after it
- reads a command but before executing it. B\bBa\bas\bsh\bh displays P\bPS\bS4\b4 as de-
- scribed above before tracing each command when the -\b-x\bx option is en-
- abled. B\bBa\bas\bsh\bh allows these prompt strings to be customized by inserting
- a number of backslash-escaped special characters that are decoded as
+ it is ready to read a command, and the secondary prompt P\bPS\bS2\b2 when it
+ needs more input to complete a command. B\bBa\bas\bsh\bh displays P\bPS\bS0\b0 after it
+ reads a command but before executing it. B\bBa\bas\bsh\bh displays P\bPS\bS4\b4 as de-
+ scribed above before tracing each command when the -\b-x\bx option is en-
+ abled. B\bBa\bas\bsh\bh allows these prompt strings to be customized by inserting
+ a number of backslash-escaped special characters that are decoded as
follows:
\\b\a\ba an ASCII bell character (07)
- \\b\d\bd the date in "Weekday Month Date" format (e.g., "Tue May
+ \\b\d\bd the date in "Weekday Month Date" format (e.g., "Tue May
26")
\\b\D\bD{\b{_\bf_\bo_\br_\bm_\ba_\bt}\b}
the _\bf_\bo_\br_\bm_\ba_\bt is passed to _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3) and the result is in-
serted into the prompt string; an empty _\bf_\bo_\br_\bm_\ba_\bt results in
- a locale-specific time representation. The braces are
+ a locale-specific time representation. The braces are
required
\\b\e\be an ASCII escape character (033)
- \\b\h\bh the hostname up to the first `.'
+ \\b\h\bh the hostname up to the first "."
\\b\H\bH the hostname
\\b\j\bj the number of jobs currently managed by the shell
\\b\l\bl the basename of the shell's terminal device name
\\b\n\bn newline
\\b\r\br carriage return
- \\b\s\bs the name of the shell, the basename of $\b$0\b0 (the portion
+ \\b\s\bs the name of the shell, the basename of $\b$0\b0 (the portion
following the final slash)
\\b\t\bt the current time in 24-hour HH:MM:SS format
\\b\T\bT the current time in 12-hour HH:MM:SS format
\\b\u\bu the username of the current user
\\b\v\bv the version of b\bba\bas\bsh\bh (e.g., 2.00)
\\b\V\bV the release of b\bba\bas\bsh\bh, version + patch level (e.g., 2.00.0)
- \\b\w\bw the value of the P\bPW\bWD\bD shell variable ($\b$P\bPW\bWD\bD), with $\b$H\bHO\bOM\bME\bE
- abbreviated with a tilde (uses the value of the
+ \\b\w\bw the value of the P\bPW\bWD\bD shell variable ($\b$P\bPW\bWD\bD), with $\b$H\bHO\bOM\bME\bE
+ abbreviated with a tilde (uses the value of the
P\bPR\bRO\bOM\bMP\bPT\bT_\b_D\bDI\bIR\bRT\bTR\bRI\bIM\bM variable)
\\b\W\bW the basename of $\b$P\bPW\bWD\bD, with $\b$H\bHO\bOM\bME\bE abbreviated with a tilde
\\b\!\b! the history number of this command
\\b\$\b$ if the effective UID is 0, a #\b#, otherwise a $\b$
\\b\_\bn_\bn_\bn the character corresponding to the octal number _\bn_\bn_\bn
\\b\\\b\ a backslash
- \\b\[\b[ begin a sequence of non-printing characters, which could
- be used to embed a terminal control sequence into the
+ \\b\[\b[ begin a sequence of non-printing characters, which could
+ be used to embed a terminal control sequence into the
prompt
\\b\]\b] end a sequence of non-printing characters
- The command number and the history number are usually different: the
- history number of a command is its position in the history list, which
- may include commands restored from the history file (see H\bHI\bIS\bST\bTO\bOR\bRY\bY be-
- low), while the command number is the position in the sequence of com-
- mands executed during the current shell session. After the string is
- decoded, it is expanded via parameter expansion, command substitution,
- arithmetic expansion, and quote removal, subject to the value of the
+ The command number and the history number are usually different: the
+ history number of a command is its position in the history list, which
+ may include commands restored from the history file (see H\bHI\bIS\bST\bTO\bOR\bRY\bY be-
+ low), while the command number is the position in the sequence of com-
+ mands executed during the current shell session. After the string is
+ decoded, it is expanded via parameter expansion, command substitution,
+ arithmetic expansion, and quote removal, subject to the value of the
p\bpr\bro\bom\bmp\bpt\btv\bva\bar\brs\bs shell option (see the description of the s\bsh\bho\bop\bpt\bt command under
S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below). This can have unwanted side effects if
escaped portions of the string appear within command substitution or
R\bRe\bea\bad\bdl\bli\bin\bne\be N\bNo\bot\bta\bat\bti\bio\bon\bn
In this section, the Emacs-style notation is used to denote keystrokes.
- Control keys are denoted by C-_\bk_\be_\by, e.g., C-n means Control-N. Simi-
- larly, _\bm_\be_\bt_\ba keys are denoted by M-_\bk_\be_\by, so M-x means Meta-X. (On key-
- boards without a _\bm_\be_\bt_\ba key, M-_\bx means ESC _\bx, i.e., press the Escape key
+ Control keys are denoted by C-_\bk_\be_\by, e.g., C-n means Control-N. Simi-
+ larly, _\bm_\be_\bt_\ba keys are denoted by M-_\bk_\be_\by, so M-x means Meta-X. (On key-
+ boards without a _\bm_\be_\bt_\ba key, M-_\bx means ESC _\bx, i.e., press the Escape key
then the _\bx key. This makes ESC the _\bm_\be_\bt_\ba _\bp_\br_\be_\bf_\bi_\bx. The combination M-C-_\bx
means ESC-Control-_\bx, or press the Escape key then hold the Control key
while pressing the _\bx key.)
Readline commands may be given numeric _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs, which normally act as
- a repeat count. Sometimes, however, it is the sign of the argument
- that is significant. Passing a negative argument to a command that
- acts in the forward direction (e.g., k\bki\bil\bll\bl-\b-l\bli\bin\bne\be) causes that command to
- act in a backward direction. Commands whose behavior with arguments
+ a repeat count. Sometimes, however, it is the sign of the argument
+ that is significant. Passing a negative argument to a command that
+ acts in the forward direction (e.g., k\bki\bil\bll\bl-\b-l\bli\bin\bne\be) causes that command to
+ act in a backward direction. Commands whose behavior with arguments
deviates from this are noted below.
- When a command is described as _\bk_\bi_\bl_\bl_\bi_\bn_\bg text, the text deleted is saved
+ When a command is described as _\bk_\bi_\bl_\bl_\bi_\bn_\bg text, the text deleted is saved
for possible future retrieval (_\by_\ba_\bn_\bk_\bi_\bn_\bg). The killed text is saved in a
_\bk_\bi_\bl_\bl _\br_\bi_\bn_\bg. Consecutive kills cause the text to be accumulated into one
unit, which can be yanked all at once. Commands which do not kill text
Readline is customized by putting commands in an initialization file
(the _\bi_\bn_\bp_\bu_\bt_\br_\bc file). The name of this file is taken from the value of
the I\bIN\bNP\bPU\bUT\bTR\bRC\bC variable. If that variable is unset, the default is _\b~_\b/_\b._\bi_\bn_\b-
- _\bp_\bu_\bt_\br_\bc. If that file does not exist or cannot be read, the ultimate
- default is _\b/_\be_\bt_\bc_\b/_\bi_\bn_\bp_\bu_\bt_\br_\bc. When a program which uses the readline li-
- brary starts up, the initialization file is read, and the key bindings
- and variables are set. There are only a few basic constructs allowed
- in the readline initialization file. Blank lines are ignored. Lines
- beginning with a #\b# are comments. Lines beginning with a $\b$ indicate
- conditional constructs. Other lines denote key bindings and variable
+ _\bp_\bu_\bt_\br_\bc. If that file does not exist or cannot be read, the ultimate
+ default is _\b/_\be_\bt_\bc_\b/_\bi_\bn_\bp_\bu_\bt_\br_\bc. When a program which uses the readline li-
+ brary starts up, the initialization file is read, and the key bindings
+ and variables are set. There are only a few basic constructs allowed
+ in the readline initialization file. Blank lines are ignored. Lines
+ beginning with a #\b# are comments. Lines beginning with a $\b$ indicate
+ conditional constructs. Other lines denote key bindings and variable
settings.
- The default key-bindings may be changed with an _\bi_\bn_\bp_\bu_\bt_\br_\bc file. Other
+ The default key-bindings may be changed with an _\bi_\bn_\bp_\bu_\bt_\br_\bc file. Other
programs that use this library may add their own commands and bindings.
For example, placing
M-Control-u: universal-argument
or
C-Meta-u: universal-argument
- into the _\bi_\bn_\bp_\bu_\bt_\br_\bc would make M-C-u execute the readline command _\bu_\bn_\bi_\bv_\be_\br_\b-
+
+ into the _\bi_\bn_\bp_\bu_\bt_\br_\bc would make M-C-u execute the readline command _\bu_\bn_\bi_\bv_\be_\br_\b-
_\bs_\ba_\bl_\b-_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt.
- The following symbolic character names are recognized: _\bR_\bU_\bB_\bO_\bU_\bT, _\bD_\bE_\bL,
+ The following symbolic character names are recognized: _\bR_\bU_\bB_\bO_\bU_\bT, _\bD_\bE_\bL,
_\bE_\bS_\bC, _\bL_\bF_\bD, _\bN_\bE_\bW_\bL_\bI_\bN_\bE, _\bR_\bE_\bT, _\bR_\bE_\bT_\bU_\bR_\bN, _\bS_\bP_\bC, _\bS_\bP_\bA_\bC_\bE, and _\bT_\bA_\bB.
- In addition to command names, readline allows keys to be bound to a
+ In addition to command names, readline allows keys to be bound to a
string that is inserted when the key is pressed (a _\bm_\ba_\bc_\br_\bo).
R\bRe\bea\bad\bdl\bli\bin\bne\be K\bKe\bey\by B\bBi\bin\bnd\bdi\bin\bng\bgs\bs
- The syntax for controlling key bindings in the _\bi_\bn_\bp_\bu_\bt_\br_\bc file is simple.
- All that is required is the name of the command or the text of a macro
+ The syntax for controlling key bindings in the _\bi_\bn_\bp_\bu_\bt_\br_\bc file is simple.
+ All that is required is the name of the command or the text of a macro
and a key sequence to which it should be bound. The name may be speci-
fied in one of two ways: as a symbolic key name, possibly with _\bM_\be_\bt_\ba_\b- or
_\bC_\bo_\bn_\bt_\br_\bo_\bl_\b- prefixes, or as a key sequence.
In the above example, _\bC_\b-_\bu is bound to the function u\bun\bni\biv\bve\ber\brs\bsa\bal\bl-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt,
_\bM_\b-_\bD_\bE_\bL is bound to the function b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-k\bki\bil\bll\bl-\b-w\bwo\bor\brd\bd, and _\bC_\b-_\bo is bound to
run the macro expressed on the right hand side (that is, to insert the
- text ``> output'' into the line).
+ text "> output" into the line).
In the second form, "\b"k\bke\bey\bys\bse\beq\bq"\b":_\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be or _\bm_\ba_\bc_\br_\bo, k\bke\bey\bys\bse\beq\bq differs
from k\bke\bey\byn\bna\bam\bme\be above in that strings denoting an entire key sequence may
"\e[11~": "Function Key 1"
In this example, _\bC_\b-_\bu is again bound to the function u\bun\bni\biv\bve\ber\brs\bsa\bal\bl-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt.
- _\bC_\b-_\bx _\bC_\b-_\br is bound to the function r\bre\be-\b-r\bre\bea\bad\bd-\b-i\bin\bni\bit\bt-\b-f\bfi\bil\ble\be, and _\bE_\bS_\bC _\b[ _\b1 _\b1 _\b~ is
- bound to insert the text ``Function Key 1''.
+ _\bC_\b-_\bx _\bC_\b-_\br is bound to the function r\bre\be-\b-r\bre\bea\bad\bd-\b-i\bin\bni\bit\bt-\b-f\bfi\bil\ble\be, and _\bE_\bS_\bC _\b[ _\b1 _\b1 _\b~ is
+ bound to insert the text "Function Key 1".
The full set of GNU Emacs style escape sequences is
\\b\C\bC-\b- control prefix
\\b\"\b" literal "
\\b\'\b' literal '
- In addition to the GNU Emacs style escape sequences, a second set of
+ In addition to the GNU Emacs style escape sequences, a second set of
backslash escapes is available:
\\b\a\ba alert (bell)
\\b\b\bb backspace
\\b\r\br carriage return
\\b\t\bt horizontal tab
\\b\v\bv vertical tab
- \\b\_\bn_\bn_\bn the eight-bit character whose value is the octal value
+ \\b\_\bn_\bn_\bn the eight-bit character whose value is the octal value
_\bn_\bn_\bn (one to three digits)
- \\b\x\bx_\bH_\bH the eight-bit character whose value is the hexadecimal
+ \\b\x\bx_\bH_\bH the eight-bit character whose value is the hexadecimal
value _\bH_\bH (one or two hex digits)
When entering the text of a macro, single or double quotes must be used
to indicate a macro definition. Unquoted text is assumed to be a func-
- tion name. In the macro body, the backslash escapes described above
- are expanded. Backslash will quote any other character in the macro
+ tion name. In the macro body, the backslash escapes described above
+ are expanded. Backslash will quote any other character in the macro
text, including " and '.
- B\bBa\bas\bsh\bh allows the current readline key bindings to be displayed or modi-
- fied with the b\bbi\bin\bnd\bd builtin command. The editing mode may be switched
- during interactive use by using the -\b-o\bo option to the s\bse\bet\bt builtin com-
+ B\bBa\bas\bsh\bh allows the current readline key bindings to be displayed or modi-
+ fied with the b\bbi\bin\bnd\bd builtin command. The editing mode may be switched
+ during interactive use by using the -\b-o\bo option to the s\bse\bet\bt builtin com-
mand (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
R\bRe\bea\bad\bdl\bli\bin\bne\be V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs
s\bse\bet\bt _\bv_\ba_\br_\bi_\ba_\bb_\bl_\be_\b-_\bn_\ba_\bm_\be _\bv_\ba_\bl_\bu_\be
or using the b\bbi\bin\bnd\bd builtin command (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below).
- Except where noted, readline variables can take the values O\bOn\bn or O\bOf\bff\bf
- (without regard to case). Unrecognized variable names are ignored.
- When a variable value is read, empty or null values, "on" (case-insen-
- sitive), and "1" are equivalent to O\bOn\bn. All other values are equivalent
- to O\bOf\bff\bf. The variables and their default values are:
+ Except where noted, readline variables can take the values O\bOn\bn or O\bOf\bff\bf
+ (without regard to case). Unrecognized variable names are ignored.
+ When readline reads a variable value, empty or null values, "on" (case-
+ insensitive), and "1" are equivalent to O\bOn\bn. All other values are
+ equivalent to O\bOf\bff\bf. The variables and their default values are:
a\bac\bct\bti\biv\bve\be-\b-r\bre\beg\bgi\bio\bon\bn-\b-s\bst\bta\bar\brt\bt-\b-c\bco\bol\blo\bor\br
A string variable that controls the text color and background
when displaying the text in the active region (see the descrip-
tion of e\ben\bna\bab\bbl\ble\be-\b-a\bac\bct\bti\biv\bve\be-\b-r\bre\beg\bgi\bio\bon\bn below). This string must not take
up any physical character positions on the display, so it should
- consist only of terminal escape sequences. It is output to the
- terminal before displaying the text in the active region. This
- variable is reset to the default value whenever the terminal
- type changes. The default value is the string that puts the
- terminal in standout mode, as obtained from the terminal's ter-
+ consist only of terminal escape sequences. It is output to the
+ terminal before displaying the text in the active region. This
+ variable is reset to the default value whenever the terminal
+ type changes. The default value is the string that puts the
+ terminal in standout mode, as obtained from the terminal's ter-
minfo description. A sample value might be "\e[01;33m".
a\bac\bct\bti\biv\bve\be-\b-r\bre\beg\bgi\bio\bon\bn-\b-e\ben\bnd\bd-\b-c\bco\bol\blo\bor\br
- A string variable that "undoes" the effects of a\bac\bct\bti\biv\bve\be-\b-r\bre\be-\b-
- g\bgi\bio\bon\bn-\b-s\bst\bta\bar\brt\bt-\b-c\bco\bol\blo\bor\br and restores "normal" terminal display appear-
- ance after displaying text in the active region. This string
- must not take up any physical character positions on the dis-
- play, so it should consist only of terminal escape sequences.
- It is output to the terminal after displaying the text in the
- active region. This variable is reset to the default value
- whenever the terminal type changes. The default value is the
- string that restores the terminal from standout mode, as ob-
+ A string variable that "undoes" the effects of a\bac\bct\bti\biv\bve\be-\b-r\bre\be-\b-
+ g\bgi\bio\bon\bn-\b-s\bst\bta\bar\brt\bt-\b-c\bco\bol\blo\bor\br and restores "normal" terminal display appear-
+ ance after displaying text in the active region. This string
+ must not take up any physical character positions on the dis-
+ play, so it should consist only of terminal escape sequences.
+ It is output to the terminal after displaying the text in the
+ active region. This variable is reset to the default value
+ whenever the terminal type changes. The default value is the
+ string that restores the terminal from standout mode, as ob-
tained from the terminal's terminfo description. A sample value
might be "\e[0m".
b\bbe\bel\bll\bl-\b-s\bst\bty\byl\ble\be (\b(a\bau\bud\bdi\bib\bbl\ble\be)\b)
Controls what happens when readline wants to ring the terminal
bell. If set to n\bno\bon\bne\be, readline never rings the bell. If set to
- v\bvi\bis\bsi\bib\bbl\ble\be, readline uses a visible bell if one is available. If
+ v\bvi\bis\bsi\bib\bbl\ble\be, readline uses a visible bell if one is available. If
set to a\bau\bud\bdi\bib\bbl\ble\be, readline attempts to ring the terminal's bell.
b\bbi\bin\bnd\bd-\b-t\btt\bty\by-\b-s\bsp\bpe\bec\bci\bia\bal\bl-\b-c\bch\bha\bar\brs\bs (\b(O\bOn\bn)\b)
- If set to O\bOn\bn (the default), readline attempts to bind the con-
- trol characters that are treated specially by the kernel's ter-
+ If set to O\bOn\bn (the default), readline attempts to bind the con-
+ trol characters that are treated specially by the kernel's ter-
minal driver to their readline equivalents. These override the
- default readline bindings described here. Type stty -a at a
- bash prompt to see your current terminal settings, including the
+ default readline bindings described here. Type "stty -a" at a
+ b\bba\bas\bsh\bh prompt to see your current terminal settings, including the
special control characters (usually c\bcc\bch\bha\bar\brs\bs).
b\bbl\bli\bin\bnk\bk-\b-m\bma\bat\btc\bch\bhi\bin\bng\bg-\b-p\bpa\bar\bre\ben\bn (\b(O\bOf\bff\bf)\b)
If set to O\bOn\bn, readline attempts to briefly move the cursor to an
c\bco\bol\blo\bor\bre\bed\bd-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn-\b-p\bpr\bre\bef\bfi\bix\bx (\b(O\bOf\bff\bf)\b)
If set to O\bOn\bn, when listing completions, readline displays the
common prefix of the set of possible completions using a differ-
- ent color. The color definitions are taken from the value of
+ ent color. The color definitions are taken from the value of
the L\bLS\bS_\b_C\bCO\bOL\bLO\bOR\bRS\bS environment variable. If there is a color defini-
tion in $\b$L\bLS\bS_\b_C\bCO\bOL\bLO\bOR\bRS\bS for the custom suffix "readline-colored-com-
pletion-prefix", readline uses this color for the common prefix
ferent colors to indicate their file type. The color defini-
tions are taken from the value of the L\bLS\bS_\b_C\bCO\bOL\bLO\bOR\bRS\bS environment
variable.
- c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn (\b(`\b``\b`#\b#'\b''\b')\b)
+ c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn (\b("#\b#")\b)
The string that is inserted when the readline i\bin\bns\bse\ber\brt\bt-\b-c\bco\bom\bmm\bme\ben\bnt\bt
command is executed. This command is bound to M\bM-\b-#\b# in emacs mode
and to #\b# in vi command mode.
c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn-\b-d\bdi\bis\bsp\bpl\bla\bay\by-\b-w\bwi\bid\bdt\bth\bh (\b(-\b-1\b1)\b)
- The number of screen columns used to display possible matches
- when performing completion. The value is ignored if it is less
- than 0 or greater than the terminal screen width. A value of 0
- will cause matches to be displayed one per line. The default
+ The number of screen columns used to display possible matches
+ when performing completion. The value is ignored if it is less
+ than 0 or greater than the terminal screen width. A value of 0
+ will cause matches to be displayed one per line. The default
value is -1.
c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn-\b-i\big\bgn\bno\bor\bre\be-\b-c\bca\bas\bse\be (\b(O\bOf\bff\bf)\b)
If set to O\bOn\bn, readline performs filename matching and completion
c\bco\bon\bnv\bve\ber\brt\bt-\b-m\bme\bet\bta\ba (\b(O\bOn\bn)\b)
If set to O\bOn\bn, readline will convert characters with the eighth
bit set to an ASCII key sequence by stripping the eighth bit and
- prefixing an escape character (in effect, using escape as the
- _\bm_\be_\bt_\ba _\bp_\br_\be_\bf_\bi_\bx). The default is _\bO_\bn, but readline will set it to
- _\bO_\bf_\bf if the locale contains eight-bit characters. This variable
- is dependent on the L\bLC\bC_\b_C\bCT\bTY\bYP\bPE\bE locale category, and may change if
+ prefixing an escape character (in effect, using escape as the
+ _\bm_\be_\bt_\ba _\bp_\br_\be_\bf_\bi_\bx). The default is _\bO_\bn, but readline will set it to
+ _\bO_\bf_\bf if the locale contains eight-bit characters. This variable
+ is dependent on the L\bLC\bC_\b_C\bCT\bTY\bYP\bPE\bE locale category, and may change if
the locale is changed.
d\bdi\bis\bsa\bab\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn (\b(O\bOf\bff\bf)\b)
If set to O\bOn\bn, readline will inhibit word completion. Completion
ilar to _\bE_\bm_\ba_\bc_\bs or _\bv_\bi. e\bed\bdi\bit\bti\bin\bng\bg-\b-m\bmo\bod\bde\be can be set to either e\bem\bma\bac\bcs\bs or
v\bvi\bi.
e\bem\bma\bac\bcs\bs-\b-m\bmo\bod\bde\be-\b-s\bst\btr\bri\bin\bng\bg (\b(@\b@)\b)
- If the _\bs_\bh_\bo_\bw_\b-_\bm_\bo_\bd_\be_\b-_\bi_\bn_\b-_\bp_\br_\bo_\bm_\bp_\bt variable is enabled, this string is
+ If the _\bs_\bh_\bo_\bw_\b-_\bm_\bo_\bd_\be_\b-_\bi_\bn_\b-_\bp_\br_\bo_\bm_\bp_\bt variable is enabled, this string is
displayed immediately before the last line of the primary prompt
when emacs editing mode is active. The value is expanded like a
- key binding, so the standard set of meta- and control prefixes
- and backslash escape sequences is available. Use the \1 and \2
- escapes to begin and end sequences of non-printing characters,
- which can be used to embed a terminal control sequence into the
+ key binding, so the standard set of meta- and control prefixes
+ and backslash escape sequences is available. Use the \1 and \2
+ escapes to begin and end sequences of non-printing characters,
+ which can be used to embed a terminal control sequence into the
mode string.
e\ben\bna\bab\bbl\ble\be-\b-a\bac\bct\bti\biv\bve\be-\b-r\bre\beg\bgi\bio\bon\bn (\b(O\bOn\bn)\b)
- The _\bp_\bo_\bi_\bn_\bt is the current cursor position, and _\bm_\ba_\br_\bk refers to a
- saved cursor position. The text between the point and mark is
- referred to as the _\br_\be_\bg_\bi_\bo_\bn. When this variable is set to _\bO_\bn,
- readline allows certain commands to designate the region as _\ba_\bc_\b-
- _\bt_\bi_\bv_\be. When the region is active, readline highlights the text
- in the region using the value of the a\bac\bct\bti\biv\bve\be-\b-r\bre\beg\bgi\bio\bon\bn-\b-s\bst\bta\bar\brt\bt-\b-c\bco\bol\blo\bor\br,
- which defaults to the string that enables the terminal's stand-
- out mode. The active region shows the text inserted by brack-
- eted-paste and any matching text found by incremental and non-
+ The _\bp_\bo_\bi_\bn_\bt is the current cursor position, and _\bm_\ba_\br_\bk refers to a
+ saved cursor position. The text between the point and mark is
+ referred to as the _\br_\be_\bg_\bi_\bo_\bn. When this variable is set to _\bO_\bn,
+ readline allows certain commands to designate the region as _\ba_\bc_\b-
+ _\bt_\bi_\bv_\be. When the region is active, readline highlights the text
+ in the region using the value of the a\bac\bct\bti\biv\bve\be-\b-r\bre\beg\bgi\bio\bon\bn-\b-s\bst\bta\bar\brt\bt-\b-c\bco\bol\blo\bor\br,
+ which defaults to the string that enables the terminal's stand-
+ out mode. The active region shows the text inserted by brack-
+ eted-paste and any matching text found by incremental and non-
incremental history searches.
e\ben\bna\bab\bbl\ble\be-\b-b\bbr\bra\bac\bck\bke\bet\bte\bed\bd-\b-p\bpa\bas\bst\bte\be (\b(O\bOn\bn)\b)
- When set to O\bOn\bn, readline configures the terminal to insert each
- paste into the editing buffer as a single string of characters,
- instead of treating each character as if it had been read from
+ When set to O\bOn\bn, readline configures the terminal to insert each
+ paste into the editing buffer as a single string of characters,
+ instead of treating each character as if it had been read from
the keyboard. This prevents readline from executing any editing
commands bound to key sequences appearing in the pasted text.
e\ben\bna\bab\bbl\ble\be-\b-k\bke\bey\byp\bpa\bad\bd (\b(O\bOf\bff\bf)\b)
Set the maximum number of history entries saved in the history
list. If set to zero, any existing history entries are deleted
and no new entries are saved. If set to a value less than zero,
- the number of history entries is not limited. By default, the
- number of history entries is set to the value of the H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE
- shell variable. If an attempt is made to set _\bh_\bi_\bs_\bt_\bo_\br_\by_\b-_\bs_\bi_\bz_\be to a
+ the number of history entries is not limited. By default, the
+ number of history entries is set to the value of the H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE
+ shell variable. If an attempt is made to set _\bh_\bi_\bs_\bt_\bo_\br_\by_\b-_\bs_\bi_\bz_\be to a
non-numeric value, the maximum number of history entries will be
set to 500.
h\bho\bor\bri\biz\bzo\bon\bnt\bta\bal\bl-\b-s\bsc\bcr\bro\bol\bll\bl-\b-m\bmo\bod\bde\be (\b(O\bOf\bff\bf)\b)
When set to O\bOn\bn, makes readline use a single line for display,
scrolling the input horizontally on a single screen line when it
- becomes longer than the screen width rather than wrapping to a
- new line. This setting is automatically enabled for terminals
+ becomes longer than the screen width rather than wrapping to a
+ new line. This setting is automatically enabled for terminals
of height 1.
i\bin\bnp\bpu\but\bt-\b-m\bme\bet\bta\ba (\b(O\bOf\bff\bf)\b)
- If set to O\bOn\bn, readline will enable eight-bit input (that is, it
+ If set to O\bOn\bn, readline will enable eight-bit input (that is, it
will not strip the eighth bit from the characters it reads), re-
gardless of what the terminal claims it can support. The name
m\bme\bet\bta\ba-\b-f\bfl\bla\bag\bg is a synonym for this variable. The default is _\bO_\bf_\bf,
but readline will set it to _\bO_\bn if the locale contains eight-bit
characters. This variable is dependent on the L\bLC\bC_\b_C\bCT\bTY\bYP\bPE\bE locale
category, and may change if the locale is changed.
- i\bis\bse\bea\bar\brc\bch\bh-\b-t\bte\ber\brm\bmi\bin\bna\bat\bto\bor\brs\bs (\b(`\b``\b`C\bC-\b-[\b[C\bC-\b-J\bJ'\b''\b')\b)
+ i\bis\bse\bea\bar\brc\bch\bh-\b-t\bte\ber\brm\bmi\bin\bna\bat\bto\bor\brs\bs (\b("C\bC-\b-[\b[C\bC-\b-J\bJ")\b)
The string of characters that should terminate an incremental
search without subsequently executing the character as a com-
mand. If this variable has not been given a value, the charac-
Specifies the duration _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will wait for a character when
reading an ambiguous key sequence (one that can form a complete
key sequence using the input read so far, or can take additional
- input to complete a longer key sequence). If no input is re-
- ceived within the timeout, _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will use the shorter but
- complete key sequence. The value is specified in milliseconds,
- so a value of 1000 means that _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will wait one second for
- additional input. If this variable is set to a value less than
- or equal to zero, or to a non-numeric value, _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will wait
- until another key is pressed to decide which key sequence to
+ input to complete a longer key sequence). If no input is re-
+ ceived within the timeout, _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will use the shorter but
+ complete key sequence. The value is specified in milliseconds,
+ so a value of 1000 means that _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will wait one second for
+ additional input. If this variable is set to a value less than
+ or equal to zero, or to a non-numeric value, _\br_\be_\ba_\bd_\bl_\bi_\bn_\be will wait
+ until another key is pressed to decide which key sequence to
complete.
m\bma\bar\brk\bk-\b-d\bdi\bir\bre\bec\bct\bto\bor\bri\bie\bes\bs (\b(O\bOn\bn)\b)
If set to O\bOn\bn, completed directory names have a slash appended.
m\bma\bar\brk\bk-\b-m\bmo\bod\bdi\bif\bfi\bie\bed\bd-\b-l\bli\bin\bne\bes\bs (\b(O\bOf\bff\bf)\b)
- If set to O\bOn\bn, history lines that have been modified are dis-
+ If set to O\bOn\bn, history lines that have been modified are dis-
played with a preceding asterisk (*\b*).
m\bma\bar\brk\bk-\b-s\bsy\bym\bml\bli\bin\bnk\bke\bed\bd-\b-d\bdi\bir\bre\bec\bct\bto\bor\bri\bie\bes\bs (\b(O\bOf\bff\bf)\b)
If set to O\bOn\bn, completed names which are symbolic links to direc-
tories have a slash appended (subject to the value of m\bma\bar\brk\bk-\b-d\bdi\bi-\b-
r\bre\bec\bct\bto\bor\bri\bie\bes\bs).
m\bma\bat\btc\bch\bh-\b-h\bhi\bid\bdd\bde\ben\bn-\b-f\bfi\bil\ble\bes\bs (\b(O\bOn\bn)\b)
- This variable, when set to O\bOn\bn, causes readline to match files
- whose names begin with a `.' (hidden files) when performing
- filename completion. If set to O\bOf\bff\bf, the leading `.' must be
- supplied by the user in the filename to be completed.
+ This variable, when set to O\bOn\bn, forces readline to match files
+ whose names begin with a "." (hidden files) when performing
+ filename completion. If set to O\bOf\bff\bf, the user must include the
+ leading "." in the filename to be completed.
m\bme\ben\bnu\bu-\b-c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-d\bdi\bis\bsp\bpl\bla\bay\by-\b-p\bpr\bre\bef\bfi\bix\bx (\b(O\bOf\bff\bf)\b)
If set to O\bOn\bn, menu completion displays the common prefix of the
list of possible completions (which may be empty) before cycling
through the list.
o\bou\but\btp\bpu\but\bt-\b-m\bme\bet\bta\ba (\b(O\bOf\bff\bf)\b)
- If set to O\bOn\bn, readline will display characters with the eighth
+ If set to O\bOn\bn, readline will display characters with the eighth
bit set directly rather than as a meta-prefixed escape sequence.
The default is _\bO_\bf_\bf, but readline will set it to _\bO_\bn if the locale
- contains eight-bit characters. This variable is dependent on
- the L\bLC\bC_\b_C\bCT\bTY\bYP\bPE\bE locale category, and may change if the locale is
+ contains eight-bit characters. This variable is dependent on
+ the L\bLC\bC_\b_C\bCT\bTY\bYP\bPE\bE locale category, and may change if the locale is
changed.
p\bpa\bag\bge\be-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs (\b(O\bOn\bn)\b)
- If set to O\bOn\bn, readline uses an internal _\bm_\bo_\br_\be-like pager to dis-
+ If set to O\bOn\bn, readline uses an internal _\bm_\bo_\br_\be-like pager to dis-
play a screenful of possible completions at a time.
p\bpr\bri\bin\bnt\bt-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs-\b-h\bho\bor\bri\biz\bzo\bon\bnt\bta\bal\bll\bly\by (\b(O\bOf\bff\bf)\b)
- If set to O\bOn\bn, readline will display completions with matches
- sorted horizontally in alphabetical order, rather than down the
+ If set to O\bOn\bn, readline will display completions with matches
+ sorted horizontally in alphabetical order, rather than down the
screen.
r\bre\bev\bve\ber\brt\bt-\b-a\bal\bll\bl-\b-a\bat\bt-\b-n\bne\bew\bwl\bli\bin\bne\be (\b(O\bOf\bff\bf)\b)
- If set to O\bOn\bn, readline will undo all changes to history lines
+ If set to O\bOn\bn, readline will undo all changes to history lines
before returning when a\bac\bcc\bce\bep\bpt\bt-\b-l\bli\bin\bne\be is executed. By default, his-
tory lines may be modified and retain individual undo lists
across calls to r\bre\bea\bad\bdl\bli\bin\bne\be.
s\bsh\bho\bow\bw-\b-a\bal\bll\bl-\b-i\bif\bf-\b-a\bam\bmb\bbi\big\bgu\buo\bou\bus\bs (\b(O\bOf\bff\bf)\b)
This alters the default behavior of the completion functions.
If set to O\bOn\bn, words which have more than one possible completion
- cause the matches to be listed immediately instead of ringing
+ cause the matches to be listed immediately instead of ringing
the bell.
s\bsh\bho\bow\bw-\b-a\bal\bll\bl-\b-i\bif\bf-\b-u\bun\bnm\bmo\bod\bdi\bif\bfi\bie\bed\bd (\b(O\bOf\bff\bf)\b)
- This alters the default behavior of the completion functions in
+ This alters the default behavior of the completion functions in
a fashion similar to s\bsh\bho\bow\bw-\b-a\bal\bll\bl-\b-i\bif\bf-\b-a\bam\bmb\bbi\big\bgu\buo\bou\bus\bs. If set to O\bOn\bn, words
which have more than one possible completion without any possi-
ble partial completion (the possible completions don't share a
v\bvi\bi-\b-c\bcm\bmd\bd-\b-m\bmo\bod\bde\be-\b-s\bst\btr\bri\bin\bng\bg (\b((\b(c\bcm\bmd\bd)\b))\b)
If the _\bs_\bh_\bo_\bw_\b-_\bm_\bo_\bd_\be_\b-_\bi_\bn_\b-_\bp_\br_\bo_\bm_\bp_\bt variable is enabled, this string is
displayed immediately before the last line of the primary prompt
- when vi editing mode is active and in command mode. The value
+ when vi editing mode is active and in command mode. The value
is expanded like a key binding, so the standard set of meta- and
control prefixes and backslash escape sequences is available.
Use the \1 and \2 escapes to begin and end sequences of non-
displayed immediately before the last line of the primary prompt
when vi editing mode is active and in insertion mode. The value
is expanded like a key binding, so the standard set of meta- and
- control prefixes and backslash escape sequences is available.
- Use the \1 and \2 escapes to begin and end sequences of non-
- printing characters, which can be used to embed a terminal con-
+ control prefixes and backslash escape sequences is available.
+ Use the \1 and \2 escapes to begin and end sequences of non-
+ printing characters, which can be used to embed a terminal con-
trol sequence into the mode string.
v\bvi\bis\bsi\bib\bbl\ble\be-\b-s\bst\bta\bat\bts\bs (\b(O\bOf\bff\bf)\b)
- If set to O\bOn\bn, a character denoting a file's type as reported by
- _\bs_\bt_\ba_\bt(2) is appended to the filename when listing possible com-
+ If set to O\bOn\bn, a character denoting a file's type as reported by
+ _\bs_\bt_\ba_\bt(2) is appended to the filename when listing possible com-
pletions.
R\bRe\bea\bad\bdl\bli\bin\bne\be C\bCo\bon\bnd\bdi\bit\bti\bio\bon\bna\bal\bl C\bCo\bon\bns\bst\btr\bru\buc\bct\bts\bs
- Readline implements a facility similar in spirit to the conditional
- compilation features of the C preprocessor which allows key bindings
- and variable settings to be performed as the result of tests. There
+ Readline implements a facility similar in spirit to the conditional
+ compilation features of the C preprocessor which allows key bindings
+ and variable settings to be performed as the result of tests. There
are four parser directives used.
- $\b$i\bif\bf The $\b$i\bif\bf construct allows bindings to be made based on the edit-
- ing mode, the terminal being used, or the application using
- readline. The text of the test, after any comparison operator,
+ $\b$i\bif\bf The $\b$i\bif\bf construct allows bindings to be made based on the edit-
+ ing mode, the terminal being used, or the application using
+ readline. The text of the test, after any comparison operator,
extends to the end of the line; unless otherwise noted, no char-
acters are required to isolate it.
key bindings, perhaps to bind the key sequences output by
the terminal's function keys. The word on the right side
of the =\b= is tested against both the full name of the ter-
- minal and the portion of the terminal name before the
- first -\b-. This allows _\bs_\bu_\bn to match both _\bs_\bu_\bn and _\bs_\bu_\bn_\b-_\bc_\bm_\bd,
+ minal and the portion of the terminal name before the
+ first -\b-. This allows _\bs_\bu_\bn to match both _\bs_\bu_\bn and _\bs_\bu_\bn_\b-_\bc_\bm_\bd,
for instance.
v\bve\ber\brs\bsi\bio\bon\bn
- The v\bve\ber\brs\bsi\bio\bon\bn test may be used to perform comparisons
- against specific readline versions. The v\bve\ber\brs\bsi\bio\bon\bn expands
- to the current readline version. The set of comparison
- operators includes =\b=, (and =\b==\b=), !\b!=\b=, <\b<=\b=, >\b>=\b=, <\b<, and >\b>.
- The version number supplied on the right side of the op-
- erator consists of a major version number, an optional
+ The v\bve\ber\brs\bsi\bio\bon\bn test may be used to perform comparisons
+ against specific readline versions. The v\bve\ber\brs\bsi\bio\bon\bn expands
+ to the current readline version. The set of comparison
+ operators includes =\b=, (and =\b==\b=), !\b!=\b=, <\b<=\b=, >\b>=\b=, <\b<, and >\b>.
+ The version number supplied on the right side of the op-
+ erator consists of a major version number, an optional
decimal point, and an optional minor version (e.g., 7\b7.\b.1\b1).
If the minor version is omitted, it is assumed to be 0\b0.
The operator may be separated from the string v\bve\ber\brs\bsi\bio\bon\bn and
from the version number argument by whitespace.
- a\bap\bpp\bpl\bli\bic\bca\bat\bti\bio\bon\bn
- The a\bap\bpp\bpl\bli\bic\bca\bat\bti\bio\bon\bn construct is used to include application-
+ _\ba_\bp_\bp_\bl_\bi_\bc_\ba_\bt_\bi_\bo_\bn
+ The _\ba_\bp_\bp_\bl_\bi_\bc_\ba_\bt_\bi_\bo_\bn construct is used to include application-
specific settings. Each program using the readline li-
brary sets the _\ba_\bp_\bp_\bl_\bi_\bc_\ba_\bt_\bi_\bo_\bn _\bn_\ba_\bm_\be, and an initialization
file can test for a particular value. This could be used
- to bind key sequences to functions useful for a specific
- program. For instance, the following command adds a key
- sequence that quotes the current or previous word in
+ to bind key sequences to functions useful for a specific
+ program. For instance, the following command adds a key
+ sequence that quotes the current or previous word in
b\bba\bas\bsh\bh:
$\b$i\bif\bf Bash
readline variables and values. The permitted comparison
operators are _\b=, _\b=_\b=, and _\b!_\b=. The variable name must be
separated from the comparison operator by whitespace; the
- operator may be separated from the value on the right
- hand side by whitespace. Both string and boolean vari-
- ables may be tested. Boolean variables must be tested
+ operator may be separated from the value on the right
+ hand side by whitespace. Both string and boolean vari-
+ ables may be tested. Boolean variables must be tested
against the values _\bo_\bn and _\bo_\bf_\bf.
$\b$e\ben\bnd\bdi\bif\bf This command, as seen in the previous example, terminates an $\b$i\bif\bf
test fails.
$\b$i\bin\bnc\bcl\blu\bud\bde\be
- This directive takes a single filename as an argument and reads
- commands and bindings from that file. For example, the follow-
+ This directive takes a single filename as an argument and reads
+ commands and bindings from that file. For example, the follow-
ing directive would read _\b/_\be_\bt_\bc_\b/_\bi_\bn_\bp_\bu_\bt_\br_\bc:
$\b$i\bin\bnc\bcl\blu\bud\bde\be _\b/_\be_\bt_\bc_\b/_\bi_\bn_\bp_\bu_\bt_\br_\bc
S\bSe\bea\bar\brc\bch\bhi\bin\bng\bg
- Readline provides commands for searching through the command history
+ Readline provides commands for searching through the command history
(see H\bHI\bIS\bST\bTO\bOR\bRY\bY below) for lines containing a specified string. There are
two search modes: _\bi_\bn_\bc_\br_\be_\bm_\be_\bn_\bt_\ba_\bl and _\bn_\bo_\bn_\b-_\bi_\bn_\bc_\br_\be_\bm_\be_\bn_\bt_\ba_\bl.
Incremental searches begin before the user has finished typing the
search string. As each character of the search string is typed, read-
line displays the next entry from the history matching the string typed
- so far. An incremental search requires only as many characters as
- needed to find the desired history entry. The characters present in
- the value of the i\bis\bse\bea\bar\brc\bch\bh-\b-t\bte\ber\brm\bmi\bin\bna\bat\bto\bor\brs\bs variable are used to terminate an
+ so far. An incremental search requires only as many characters as
+ needed to find the desired history entry. The characters present in
+ the value of the i\bis\bse\bea\bar\brc\bch\bh-\b-t\bte\ber\brm\bmi\bin\bna\bat\bto\bor\brs\bs variable are used to terminate an
incremental search. If that variable has not been assigned a value the
Escape and Control-J characters will terminate an incremental search.
Control-G will abort an incremental search and restore the original
Readline remembers the last incremental search string. If two Control-
Rs are typed without any intervening characters defining a new search
- string, any remembered search string is used.
+ string, readline uses any remembered search string.
Non-incremental searches read the entire search string before starting
to search for matching history lines. The search string may be typed
Move forward to the end of the next word. Words are composed of
alphanumeric characters (letters and digits).
b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-b\bb)\b)
- Move back to the start of the current or previous word. Words
+ Move back to the start of the current or previous word. Words
are composed of alphanumeric characters (letters and digits).
s\bsh\bhe\bel\bll\bl-\b-f\bfo\bor\brw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd
- Move forward to the end of the next word. Words are delimited
+ Move forward to the end of the next word. Words are delimited
by non-quoted shell metacharacters.
s\bsh\bhe\bel\bll\bl-\b-b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd
- Move back to the start of the current or previous word. Words
+ Move back to the start of the current or previous word. Words
are delimited by non-quoted shell metacharacters.
p\bpr\bre\bev\bvi\bio\bou\bus\bs-\b-s\bsc\bcr\bre\bee\ben\bn-\b-l\bli\bin\bne\be
- Attempt to move point to the same physical screen column on the
- previous physical screen line. This will not have the desired
- effect if the current readline line does not take up more than
- one physical line or if point is not greater than the length of
+ Attempt to move point to the same physical screen column on the
+ previous physical screen line. This will not have the desired
+ effect if the current readline line does not take up more than
+ one physical line or if point is not greater than the length of
the prompt plus the screen width.
n\bne\bex\bxt\bt-\b-s\bsc\bcr\bre\bee\ben\bn-\b-l\bli\bin\bne\be
- Attempt to move point to the same physical screen column on the
+ Attempt to move point to the same physical screen column on the
next physical screen line. This will not have the desired effect
if the current readline line does not take up more than one
physical line or if the length of the current readline line is
at the top of the screen.
c\bcl\ble\bea\bar\br-\b-s\bsc\bcr\bre\bee\ben\bn (\b(C\bC-\b-l\bl)\b)
Clear the screen, then redraw the current line, leaving the cur-
- rent line at the top of the screen. With an argument, refresh
+ rent line at the top of the screen. With an argument, refresh
the current line without clearing the screen.
r\bre\bed\bdr\bra\baw\bw-\b-c\bcu\bur\brr\bre\ben\bnt\bt-\b-l\bli\bin\bne\be
Refresh the current line.
Fetch the previous command from the history list, moving back in
the list.
n\bne\bex\bxt\bt-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(C\bC-\b-n\bn)\b)
- Fetch the next command from the history list, moving forward in
+ Fetch the next command from the history list, moving forward in
the list.
b\bbe\beg\bgi\bin\bnn\bni\bin\bng\bg-\b-o\bof\bf-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(M\bM-\b-<\b<)\b)
Move to the first line in the history.
e\ben\bnd\bd-\b-o\bof\bf-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(M\bM-\b->\b>)\b)
- Move to the end of the input history, i.e., the line currently
+ Move to the end of the input history, i.e., the line currently
being entered.
o\bop\bpe\ber\bra\bat\bte\be-\b-a\ban\bnd\bd-\b-g\bge\bet\bt-\b-n\bne\bex\bxt\bt (\b(C\bC-\b-o\bo)\b)
- Accept the current line for execution and fetch the next line
- relative to the current line from the history for editing. A
- numeric argument, if supplied, specifies the history entry to
+ Accept the current line for execution and fetch the next line
+ relative to the current line from the history for editing. A
+ numeric argument, if supplied, specifies the history entry to
use instead of the current line.
f\bfe\bet\btc\bch\bh-\b-h\bhi\bis\bst\bto\bor\bry\by
- With a numeric argument, fetch that entry from the history list
+ With a numeric argument, fetch that entry from the history list
and make it the current line. Without an argument, move back to
the first entry in the history list.
r\bre\bev\bve\ber\brs\bse\be-\b-s\bse\bea\bar\brc\bch\bh-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(C\bC-\b-r\br)\b)
- Search backward starting at the current line and moving `up'
+ Search backward starting at the current line and moving "up"
through the history as necessary. This is an incremental
search.
f\bfo\bor\brw\bwa\bar\brd\bd-\b-s\bse\bea\bar\brc\bch\bh-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(C\bC-\b-s\bs)\b)
- Search forward starting at the current line and moving `down'
+ Search forward starting at the current line and moving "down"
through the history as necessary. This is an incremental
search.
n\bno\bon\bn-\b-i\bin\bnc\bcr\bre\bem\bme\ben\bnt\bta\bal\bl-\b-r\bre\bev\bve\ber\brs\bse\be-\b-s\bse\bea\bar\brc\bch\bh-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(M\bM-\b-p\bp)\b)
Search backward through the history starting at the current line
- using a non-incremental search for a string supplied by the
+ using a non-incremental search for a string supplied by the
user.
n\bno\bon\bn-\b-i\bin\bnc\bcr\bre\bem\bme\ben\bnt\bta\bal\bl-\b-f\bfo\bor\brw\bwa\bar\brd\bd-\b-s\bse\bea\bar\brc\bch\bh-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(M\bM-\b-n\bn)\b)
- Search forward through the history using a non-incremental
+ Search forward through the history using a non-incremental
search for a string supplied by the user.
h\bhi\bis\bst\bto\bor\bry\by-\b-s\bse\bea\bar\brc\bch\bh-\b-f\bfo\bor\brw\bwa\bar\brd\bd
- Search forward through the history for the string of characters
- between the start of the current line and the point. This is a
+ Search forward through the history for the string of characters
+ between the start of the current line and the point. This is a
non-incremental search.
h\bhi\bis\bst\bto\bor\bry\by-\b-s\bse\bea\bar\brc\bch\bh-\b-b\bba\bac\bck\bkw\bwa\bar\brd\bd
Search backward through the history for the string of characters
h\bhi\bis\bst\bto\bor\bry\by-\b-s\bsu\bub\bbs\bst\btr\bri\bin\bng\bg-\b-s\bse\bea\bar\brc\bch\bh-\b-f\bfo\bor\brw\bwa\bar\brd\bd
Search forward through the history for the string of characters
between the start of the current line and the point. The search
- string may match anywhere in a history line. This is a non-in-
+ string may match anywhere in a history line. This is a non-in-
cremental search.
y\bya\ban\bnk\bk-\b-n\bnt\bth\bh-\b-a\bar\brg\bg (\b(M\bM-\b-C\bC-\b-y\by)\b)
- Insert the first argument to the previous command (usually the
+ Insert the first argument to the previous command (usually the
second word on the previous line) at point. With an argument _\bn,
insert the _\bnth word from the previous command (the words in the
previous command begin with word 0). A negative argument in-
y\bya\ban\bnk\bk-\b-l\bla\bas\bst\bt-\b-a\bar\brg\bg (\b(M\bM-\b-.\b.,\b, M\bM-\b-_\b_)\b)
Insert the last argument to the previous command (the last word
of the previous history entry). With a numeric argument, behave
- exactly like y\bya\ban\bnk\bk-\b-n\bnt\bth\bh-\b-a\bar\brg\bg. Successive calls to y\bya\ban\bnk\bk-\b-l\bla\bas\bst\bt-\b-a\bar\brg\bg
- move back through the history list, inserting the last word (or
- the word specified by the argument to the first call) of each
+ exactly like y\bya\ban\bnk\bk-\b-n\bnt\bth\bh-\b-a\bar\brg\bg. Successive calls to y\bya\ban\bnk\bk-\b-l\bla\bas\bst\bt-\b-a\bar\brg\bg
+ move back through the history list, inserting the last word (or
+ the word specified by the argument to the first call) of each
line in turn. Any numeric argument supplied to these successive
calls determines the direction to move through the history. A
negative argument switches the direction through the history
s\bsh\bhe\bel\bll\bl-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-l\bli\bin\bne\be (\b(M\bM-\b-C\bC-\b-e\be)\b)
Expand the line by performing shell word expansions. This per-
forms alias and history expansion, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quot-
- ing, tilde expansion, parameter and variable expansion, arith-
- metic expansion, word splitting, and quote removal. See H\bHI\bIS\bST\bTO\bOR\bRY\bY
- E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN below for a description of history expansion.
+ ing, tilde expansion, parameter and variable expansion, arith-
+ metic expansion, command and process substitution, word split-
+ ting, and quote removal. An explicit argument suppresses com-
+ mand and process substitution. See H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN below for
+ a description of history expansion.
h\bhi\bis\bst\bto\bor\bry\by-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-l\bli\bin\bne\be (\b(M\bM-\b-^\b^)\b)
- Perform history expansion on the current line. See H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bX-\b-
+ Perform history expansion on the current line. See H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bX-\b-
P\bPA\bAN\bNS\bSI\bIO\bON\bN below for a description of history expansion.
m\bma\bag\bgi\bic\bc-\b-s\bsp\bpa\bac\bce\be
- Perform history expansion on the current line and insert a
+ Perform history expansion on the current line and insert a
space. See H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN below for a description of history
expansion.
a\bal\bli\bia\bas\bs-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-l\bli\bin\bne\be
C\bCo\bom\bmm\bma\ban\bnd\bds\bs f\bfo\bor\br C\bCh\bha\ban\bng\bgi\bin\bng\bg T\bTe\bex\bxt\bt
_\be_\bn_\bd_\b-_\bo_\bf_\b-_\bf_\bi_\bl_\be (\b(u\bus\bsu\bua\bal\bll\bly\by C\bC-\b-d\bd)\b)
- The character indicating end-of-file as set, for example, by
- ``stty''. If this character is read when there are no charac-
- ters on the line, and point is at the beginning of the line,
- readline interprets it as the end of input and returns E\bEO\bOF\bF.
+ The character indicating end-of-file as set, for example, by
+ _\bs_\bt_\bt_\by(1). If this character is read when there are no characters
+ on the line, and point is at the beginning of the line, readline
+ interprets it as the end of input and returns E\bEO\bOF\bF.
d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br (\b(C\bC-\b-d\bd)\b)
Delete the character at point. If this function is bound to the
same character as the tty E\bEO\bOF\bF character, as C\bC-\b-d\bd commonly is, see
above for the effects.
b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br (\b(R\bRu\bub\bbo\bou\but\bt)\b)
- Delete the character behind the cursor. When given a numeric
+ Delete the character behind the cursor. When given a numeric
argument, save the deleted text on the kill ring.
f\bfo\bor\brw\bwa\bar\brd\bd-\b-b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br
- Delete the character under the cursor, unless the cursor is at
+ Delete the character under the cursor, unless the cursor is at
the end of the line, in which case the character behind the cur-
sor is deleted.
q\bqu\buo\bot\bte\bed\bd-\b-i\bin\bns\bse\ber\brt\bt (\b(C\bC-\b-q\bq,\b, C\bC-\b-v\bv)\b)
to insert characters like C\bC-\b-q\bq, for example.
t\bta\bab\bb-\b-i\bin\bns\bse\ber\brt\bt (\b(C\bC-\b-v\bv T\bTA\bAB\bB)\b)
Insert a tab character.
- s\bse\bel\blf\bf-\b-i\bin\bns\bse\ber\brt\bt (\b(a\ba,\b, b\bb,\b, A\bA,\b, 1\b1,\b, !\b!,\b, .\b..\b..\b.)\b)
+ s\bse\bel\blf\bf-\b-i\bin\bns\bse\ber\brt\bt (\b(a\ba,\b, b\bb,\b, A\bA,\b, 1\b1,\b, !\b!,\b, ...)\b)
Insert the character typed.
t\btr\bra\ban\bns\bsp\bpo\bos\bse\be-\b-c\bch\bha\bar\brs\bs (\b(C\bC-\b-t\bt)\b)
Drag the character before point forward over the character at
Capitalize the current (or following) word. With a negative ar-
gument, capitalize the previous word, but do not move point.
o\bov\bve\ber\brw\bwr\bri\bit\bte\be-\b-m\bmo\bod\bde\be
- Toggle overwrite mode. With an explicit positive numeric argu-
+ Toggle overwrite mode. With an explicit positive numeric argu-
ment, switches to overwrite mode. With an explicit non-positive
numeric argument, switches to insert mode. This command affects
- only e\bem\bma\bac\bcs\bs mode; v\bvi\bi mode does overwrite differently. Each call
+ only e\bem\bma\bac\bcs\bs mode; v\bvi\bi mode does overwrite differently. Each call
to _\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b(_\b) starts in insert mode. In overwrite mode, charac-
ters bound to s\bse\bel\blf\bf-\b-i\bin\bns\bse\ber\brt\bt replace the text at point rather than
pushing the text to the right. Characters bound to b\bba\bac\bck\bk-\b-
ing y\bya\ban\bnk\bk or y\bya\ban\bnk\bk-\b-p\bpo\bop\bp.
N\bNu\bum\bme\ber\bri\bic\bc A\bAr\brg\bgu\bum\bme\ben\bnt\bts\bs
- d\bdi\big\bgi\bit\bt-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt (\b(M\bM-\b-0\b0,\b, M\bM-\b-1\b1,\b, .\b..\b..\b.,\b, M\bM-\b--\b-)\b)
+ d\bdi\big\bgi\bit\bt-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt (\b(M\bM-\b-0\b0,\b, M\bM-\b-1\b1,\b, ...,\b, M\bM-\b--\b-)\b)
Add this digit to the argument already accumulating, or start a
new argument. M-- starts a negative argument.
u\bun\bni\biv\bve\ber\brs\bsa\bal\bl-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt
lowed by digits, executing u\bun\bni\biv\bve\ber\brs\bsa\bal\bl-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt again ends the nu-
meric argument, but is otherwise ignored. As a special case, if
this command is immediately followed by a character that is nei-
- ther a digit nor minus sign, the argument count for the next
- command is multiplied by four. The argument count is initially
- one, so executing this function the first time makes the argu-
+ ther a digit nor minus sign, the argument count for the next
+ command is multiplied by four. The argument count is initially
+ one, so executing this function the first time makes the argu-
ment count four, a second time makes the argument count sixteen,
and so on.
c\bco\bom\bmp\bpl\ble\bet\bte\be (\b(T\bTA\bAB\bB)\b)
Attempt to perform completion on the text before point. B\bBa\bas\bsh\bh
attempts completion treating the text as a variable (if the text
- begins with $\b$), username (if the text begins with ~\b~), hostname
- (if the text begins with @\b@), or command (including aliases and
+ begins with $\b$), username (if the text begins with ~\b~), hostname
+ (if the text begins with @\b@), or command (including aliases and
functions) in turn. If none of these produces a match, filename
completion is attempted.
p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs (\b(M\bM-\b-?\b?)\b)
List the possible completions of the text before point, treating
it as a username.
c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-v\bva\bar\bri\bia\bab\bbl\ble\be (\b(M\bM-\b-$\b$)\b)
- Attempt completion on the text before point, treating it as a
+ Attempt completion on the text before point, treating it as a
shell variable.
p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-v\bva\bar\bri\bia\bab\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs (\b(C\bC-\b-x\bx $\b$)\b)
List the possible completions of the text before point, treating
List the possible completions of the text before point, treating
it as a hostname.
c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-c\bco\bom\bmm\bma\ban\bnd\bd (\b(M\bM-\b-!\b!)\b)
- Attempt completion on the text before point, treating it as a
- command name. Command completion attempts to match the text
- against aliases, reserved words, shell functions, shell
+ Attempt completion on the text before point, treating it as a
+ command name. Command completion attempts to match the text
+ against aliases, reserved words, shell functions, shell
builtins, and finally executable filenames, in that order.
p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-c\bco\bom\bmm\bma\ban\bnd\bd-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs (\b(C\bC-\b-x\bx !\b!)\b)
List the possible completions of the text before point, treating
Stop saving the characters typed into the current keyboard macro
and store the definition.
c\bca\bal\bll\bl-\b-l\bla\bas\bst\bt-\b-k\bkb\bbd\bd-\b-m\bma\bac\bcr\bro\bo (\b(C\bC-\b-x\bx e\be)\b)
- Re-execute the last keyboard macro defined, by making the char-
+ Re-execute the last keyboard macro defined, by making the char-
acters in the macro appear as if typed at the keyboard.
p\bpr\bri\bin\bnt\bt-\b-l\bla\bas\bst\bt-\b-k\bkb\bbd\bd-\b-m\bma\bac\bcr\bro\bo (\b()\b)
- Print the last keyboard macro defined in a format suitable for
+ Print the last keyboard macro defined in a format suitable for
the _\bi_\bn_\bp_\bu_\bt_\br_\bc file.
M\bMi\bis\bsc\bce\bel\bll\bla\ban\bne\beo\bou\bus\bs
r\bre\be-\b-r\bre\bea\bad\bd-\b-i\bin\bni\bit\bt-\b-f\bfi\bil\ble\be (\b(C\bC-\b-x\bx C\bC-\b-r\br)\b)
- Read in the contents of the _\bi_\bn_\bp_\bu_\bt_\br_\bc file, and incorporate any
+ Read in the contents of the _\bi_\bn_\bp_\bu_\bt_\br_\bc file, and incorporate any
bindings or variable assignments found there.
a\bab\bbo\bor\brt\bt (\b(C\bC-\b-g\bg)\b)
- Abort the current editing command and ring the terminal's bell
+ Abort the current editing command and ring the terminal's bell
(subject to the setting of b\bbe\bel\bll\bl-\b-s\bst\bty\byl\ble\be).
- d\bdo\bo-\b-l\blo\bow\bwe\ber\brc\bca\bas\bse\be-\b-v\bve\ber\brs\bsi\bio\bon\bn (\b(M\bM-\b-A\bA,\b, M\bM-\b-B\bB,\b, M\bM-\b-_\bx,\b, .\b..\b..\b.)\b)
- If the metafied character _\bx is uppercase, run the command that
+ d\bdo\bo-\b-l\blo\bow\bwe\ber\brc\bca\bas\bse\be-\b-v\bve\ber\brs\bsi\bio\bon\bn (\b(M\bM-\b-A\bA,\b, M\bM-\b-B\bB,\b, M\bM-\b-_\bx,\b, ...)\b)
+ If the metafied character _\bx is uppercase, run the command that
is bound to the corresponding metafied lowercase character. The
behavior is undefined if _\bx is already lowercase.
p\bpr\bre\bef\bfi\bix\bx-\b-m\bme\bet\bta\ba (\b(E\bES\bSC\bC)\b)
as the mark.
c\bch\bha\bar\bra\bac\bct\bte\ber\br-\b-s\bse\bea\bar\brc\bch\bh (\b(C\bC-\b-]\b])\b)
A character is read and point is moved to the next occurrence of
- that character. A negative argument searches for previous oc-
+ that character. A negative argument searches for previous oc-
currences.
c\bch\bha\bar\bra\bac\bct\bte\ber\br-\b-s\bse\bea\bar\brc\bch\bh-\b-b\bba\bac\bck\bkw\bwa\bar\brd\bd (\b(M\bM-\b-C\bC-\b-]\b])\b)
- A character is read and point is moved to the previous occur-
- rence of that character. A negative argument searches for sub-
+ A character is read and point is moved to the previous occur-
+ rence of that character. A negative argument searches for sub-
sequent occurrences.
s\bsk\bki\bip\bp-\b-c\bcs\bsi\bi-\b-s\bse\beq\bqu\bue\ben\bnc\bce\be
- Read enough characters to consume a multi-key sequence such as
- those defined for keys like Home and End. Such sequences begin
+ Read enough characters to consume a multi-key sequence such as
+ those defined for keys like Home and End. Such sequences begin
with a Control Sequence Indicator (CSI), usually ESC-[. If this
sequence is bound to "\[", keys producing such sequences will
have no effect unless explicitly bound to a readline command,
Without a numeric argument, the value of the readline c\bco\bom\bm-\b-
m\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn variable is inserted at the beginning of the current
line. If a numeric argument is supplied, this command acts as a
- toggle: if the characters at the beginning of the line do not
- match the value of c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn, the value is inserted, other-
+ toggle: if the characters at the beginning of the line do not
+ match the value of c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn, the value is inserted, other-
wise the characters in c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn are deleted from the begin-
ning of the line. In either case, the line is accepted as if a
newline had been typed. The default value of c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn
d\bdu\bum\bmp\bp-\b-f\bfu\bun\bnc\bct\bti\bio\bon\bns\bs
Print all of the functions and their key bindings to the read-
line output stream. If a numeric argument is supplied, the out-
- put is formatted in such a way that it can be made part of an
+ put is formatted in such a way that it can be made part of an
_\bi_\bn_\bp_\bu_\bt_\br_\bc file.
d\bdu\bum\bmp\bp-\b-v\bva\bar\bri\bia\bab\bbl\ble\bes\bs
Print all of the settable readline variables and their values to
Display version information about the current instance of b\bba\bas\bsh\bh.
P\bPr\bro\bog\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn
- When word completion is attempted for an argument to a command for
- which a completion specification (a _\bc_\bo_\bm_\bp_\bs_\bp_\be_\bc) has been defined using
- the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below), the program-
- mable completion facilities are invoked.
+ When word completion is attempted for an argument to a command for
+ which a completion specification (a _\bc_\bo_\bm_\bp_\bs_\bp_\be_\bc) has been defined using
+ the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below), the programma-
+ ble completion facilities are invoked.
First, the command name is identified. If the command word is the
empty string (completion attempted at the beginning of an empty line),
any compspec defined with the -\b-E\bE option to c\bco\bom\bmp\bpl\ble\bet\bte\be is used. If a
compspec has been defined for that command, the compspec is used to
generate the list of possible completions for the word. If the command
- word is a full pathname, a compspec for the full pathname is searched
- for first. If no compspec is found for the full pathname, an attempt
- is made to find a compspec for the portion following the final slash.
- If those searches do not result in a compspec, any compspec defined
- with the -\b-D\bD option to c\bco\bom\bmp\bpl\ble\bet\bte\be is used as the default. If there is no
- default compspec, b\bba\bas\bsh\bh attempts alias expansion on the command word as
- a final resort, and attempts to find a compspec for the command word
+ word is a full pathname, a compspec for the full pathname is searched
+ for first. If no compspec is found for the full pathname, an attempt
+ is made to find a compspec for the portion following the final slash.
+ If those searches do not result in a compspec, any compspec defined
+ with the -\b-D\bD option to c\bco\bom\bmp\bpl\ble\bet\bte\be is used as the default. If there is no
+ default compspec, b\bba\bas\bsh\bh attempts alias expansion on the command word as
+ a final resort, and attempts to find a compspec for the command word
from any successful expansion.
- Once a compspec has been found, it is used to generate the list of
- matching words. If a compspec is not found, the default b\bba\bas\bsh\bh comple-
+ Once a compspec has been found, it is used to generate the list of
+ matching words. If a compspec is not found, the default b\bba\bas\bsh\bh comple-
tion as described above under C\bCo\bom\bmp\bpl\ble\bet\bti\bin\bng\bg is performed.
- First, the actions specified by the compspec are used. Only matches
- which are prefixed by the word being completed are returned. When the
- -\b-f\bf or -\b-d\bd option is used for filename or directory name completion, the
+ First, the actions specified by the compspec are used. Only matches
+ which are prefixed by the word being completed are returned. When the
+ -\b-f\bf or -\b-d\bd option is used for filename or directory name completion, the
shell variable F\bFI\bIG\bGN\bNO\bOR\bRE\bE is used to filter the matches.
Any completions specified by a pathname expansion pattern to the -\b-G\bG op-
prefix-matched against the word being completed, and the matching words
become the possible completions.
- After these matches have been generated, any shell function or command
- specified with the -\b-F\bF and -\b-C\bC options is invoked. When the command or
+ After these matches have been generated, any shell function or command
+ specified with the -\b-F\bF and -\b-C\bC options is invoked. When the command or
function is invoked, the C\bCO\bOM\bMP\bP_\b_L\bLI\bIN\bNE\bE, C\bCO\bOM\bMP\bP_\b_P\bPO\bOI\bIN\bNT\bT, C\bCO\bOM\bMP\bP_\b_K\bKE\bEY\bY, and C\bCO\bOM\bMP\bP_\b_T\bTY\bYP\bPE\bE
variables are assigned values as described above under S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs.
- If a shell function is being invoked, the C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDS\bS and C\bCO\bOM\bMP\bP_\b_C\bCW\bWO\bOR\bRD\bD
- variables are also set. When the function or command is invoked, the
- first argument ($\b$1\b1) is the name of the command whose arguments are be-
- ing completed, the second argument ($\b$2\b2) is the word being completed,
- and the third argument ($\b$3\b3) is the word preceding the word being com-
+ If a shell function is being invoked, the C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDS\bS and C\bCO\bOM\bMP\bP_\b_C\bCW\bWO\bOR\bRD\bD
+ variables are also set. When the function or command is invoked, the
+ first argument ($\b$1\b1) is the name of the command whose arguments are be-
+ ing completed, the second argument ($\b$2\b2) is the word being completed,
+ and the third argument ($\b$3\b3) is the word preceding the word being com-
pleted on the current command line. No filtering of the generated com-
pletions against the word being completed is performed; the function or
command has complete freedom in generating the matches.
- Any function specified with -\b-F\bF is invoked first. The function may use
- any of the shell facilities, including the c\bco\bom\bmp\bpg\bge\ben\bn builtin described
- below, to generate the matches. It must put the possible completions
+ Any function specified with -\b-F\bF is invoked first. The function may use
+ any of the shell facilities, including the c\bco\bom\bmp\bpg\bge\ben\bn builtin described
+ below, to generate the matches. It must put the possible completions
in the C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY array variable, one per array element.
- Next, any command specified with the -\b-C\bC option is invoked in an envi-
- ronment equivalent to command substitution. It should print a list of
- completions, one per line, to the standard output. Backslash may be
+ Next, any command specified with the -\b-C\bC option is invoked in an envi-
+ ronment equivalent to command substitution. It should print a list of
+ completions, one per line, to the standard output. Backslash may be
used to escape a newline, if necessary.
- After all of the possible completions are generated, any filter speci-
- fied with the -\b-X\bX option is applied to the list. The filter is a pat-
- tern as used for pathname expansion; a &\b& in the pattern is replaced
- with the text of the word being completed. A literal &\b& may be escaped
- with a backslash; the backslash is removed before attempting a match.
- Any completion that matches the pattern will be removed from the list.
+ After all of the possible completions are generated, any filter speci-
+ fied with the -\b-X\bX option is applied to the list. The filter is a pat-
+ tern as used for pathname expansion; a &\b& in the pattern is replaced
+ with the text of the word being completed. A literal &\b& may be escaped
+ with a backslash; the backslash is removed before attempting a match.
+ Any completion that matches the pattern will be removed from the list.
A leading !\b! negates the pattern; in this case any completion not match-
ing the pattern will be removed. If the n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh shell option is
enabled, the match is performed without regard to the case of alpha-
was defined, directory name completion is attempted and any matches are
added to the results of the other actions.
- By default, if a compspec is found, whatever it generates is returned
- to the completion code as the full set of possible completions. The
+ By default, if a compspec is found, whatever it generates is returned
+ to the completion code as the full set of possible completions. The
default b\bba\bas\bsh\bh completions are not attempted, and the readline default of
filename completion is disabled. If the -\b-o\bo b\bba\bas\bsh\bhd\bde\bef\bfa\bau\bul\blt\bt option was sup-
- plied to c\bco\bom\bmp\bpl\ble\bet\bte\be when the compspec was defined, the b\bba\bas\bsh\bh default com-
+ plied to c\bco\bom\bmp\bpl\ble\bet\bte\be when the compspec was defined, the b\bba\bas\bsh\bh default com-
pletions are attempted if the compspec generates no matches. If the -\b-o\bo
d\bde\bef\bfa\bau\bul\blt\bt option was supplied to c\bco\bom\bmp\bpl\ble\bet\bte\be when the compspec was defined,
readline's default completion will be performed if the compspec (and,
completion handlers to indicate that completion should be retried by
returning an exit status of 124. If a shell function returns 124, and
changes the compspec associated with the command on which completion is
- being attempted (supplied as the first argument when the function is
+ being attempted (supplied as the first argument when the function is
executed), programmable completion restarts from the beginning, with an
attempt to find a new compspec for that command. This allows a set of
completions to be built dynamically as completion is attempted, rather
For instance, assuming that there is a library of compspecs, each kept
in a file corresponding to the name of the command, the following de-
fault completion function would load completions dynamically:
-
- _completion_loader()
- {
- . "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124
- }
- complete -D -F _completion_loader -o bashdefault -o default
-
+ _completion_loader()
+ {
+ . "/etc/bash_completion.d/$1.sh" \
+ >/dev/null 2>&1 && return 124
+ }
+ complete -D -F _completion_loader \
+ -o bashdefault -o default
H\bHI\bIS\bST\bTO\bOR\bRY\bY
When the -\b-o\bo h\bhi\bis\bst\bto\bor\bry\by option to the s\bse\bet\bt builtin is enabled, the shell
provides access to the _\bc_\bo_\bm_\bm_\ba_\bn_\bd _\bh_\bi_\bs_\bt_\bo_\br_\by, the list of commands previously
- typed. The value of the H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE variable is used as the number of
+ typed. The value of the H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE variable is used as the number of
commands to save in a history list. The text of the last H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE com-
mands (default 500) is saved. The shell stores each command in the
history list prior to parameter and variable expansion (see E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN
of the shell variables H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE and H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL.
On startup, the history is initialized from the file named by the vari-
- able H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE (default _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bh_\bi_\bs_\bt_\bo_\br_\by). The file named by the value
- of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is truncated, if necessary, to contain no more than the
- number of lines specified by the value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE. If H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE-\b-
- S\bSI\bIZ\bZE\bE is unset, or set to null, a non-numeric value, or a numeric value
- less than zero, the history file is not truncated. When the history
- file is read, lines beginning with the history comment character fol-
+ able H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE (default _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bh_\bi_\bs_\bt_\bo_\br_\by). The file named by the value
+ of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is truncated, if necessary, to contain no more than the
+ number of lines specified by the value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE. If H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE-\b-
+ S\bSI\bIZ\bZE\bE is unset, or set to null, a non-numeric value, or a numeric value
+ less than zero, the history file is not truncated. When the history
+ file is read, lines beginning with the history comment character fol-
lowed immediately by a digit are interpreted as timestamps for the fol-
lowing history line. These timestamps are optionally displayed depend-
- ing on the value of the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable. When a shell with
- history enabled exits, the last $\b$H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE lines are copied from the
- history list to $\b$H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE. If the h\bhi\bis\bst\bta\bap\bpp\bpe\ben\bnd\bd shell option is enabled
- (see the description of s\bsh\bho\bop\bpt\bt under S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below), the
- lines are appended to the history file, otherwise the history file is
- overwritten. If H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is unset or null, or if the history file is
- unwritable, the history is not saved. If the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable
- is set, time stamps are written to the history file, marked with the
- history comment character, so they may be preserved across shell ses-
- sions. This uses the history comment character to distinguish time-
+ ing on the value of the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable. When a shell with
+ history enabled exits, the last $\b$H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE lines are copied from the
+ history list to $\b$H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE. If the h\bhi\bis\bst\bta\bap\bpp\bpe\ben\bnd\bd shell option is enabled
+ (see the description of s\bsh\bho\bop\bpt\bt under S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below), the
+ lines are appended to the history file, otherwise the history file is
+ overwritten. If H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is unset or null, or if the history file is
+ unwritable, the history is not saved. If the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable
+ is set, time stamps are written to the history file, marked with the
+ history comment character, so they may be preserved across shell ses-
+ sions. This uses the history comment character to distinguish time-
stamps from other history lines. After saving the history, the history
file is truncated to contain no more than H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE lines. If H\bHI\bIS\bST\bT-\b-
- F\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE is unset, or set to null, a non-numeric value, or a numeric
+ F\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE is unset, or set to null, a non-numeric value, or a numeric
value less than zero, the history file is not truncated.
- The builtin command f\bfc\bc (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below) may be used
+ The builtin command f\bfc\bc (see S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS below) may be used
to list or edit and re-execute a portion of the history list. The h\bhi\bis\bs-\b-
t\bto\bor\bry\by builtin may be used to display or modify the history list and ma-
nipulate the history file. When using command-line editing, search
The shell allows control over which commands are saved on the history
list. The H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL and H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE variables are used to cause the
shell to save only a subset of the commands entered. The c\bcm\bmd\bdh\bhi\bis\bst\bt shell
- option, if enabled, causes the shell to attempt to save each line of a
- multi-line command in the same history entry, adding semicolons where
- necessary to preserve syntactic correctness. The l\bli\bit\bth\bhi\bis\bst\bt shell option
- causes the shell to save the command with embedded newlines instead of
+ option, if enabled, causes the shell to attempt to save each line of a
+ multi-line command in the same history entry, adding semicolons where
+ necessary to preserve syntactic correctness. The l\bli\bit\bth\bhi\bis\bst\bt shell option
+ causes the shell to save the command with embedded newlines instead of
semicolons. See the description of the s\bsh\bho\bop\bpt\bt builtin below under S\bSH\bHE\bEL\bLL\bL
B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS for information on setting and unsetting shell op-
tions.
perform history expansion by default.
History expansions introduce words from the history list into the input
- stream, making it easy to repeat commands, insert the arguments to a
+ stream, making it easy to repeat commands, insert the arguments to a
previous command into the current input line, or fix errors in previous
commands quickly.
to select portions of that line for inclusion into the current one.
The line selected from the history is the _\be_\bv_\be_\bn_\bt, and the portions of
that line that are acted upon are _\bw_\bo_\br_\bd_\bs. The line is broken into words
- in the same fashion as when reading input, so that several _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\b-
- _\bt_\be_\br-separated words surrounded by quotes are considered one word. The
- _\be_\bv_\be_\bn_\bt _\bd_\be_\bs_\bi_\bg_\bn_\ba_\bt_\bo_\br selects the event, the optional _\bw_\bo_\br_\bd _\bd_\be_\bs_\bi_\bg_\bn_\ba_\bt_\bo_\br se-
- lects words from the event, and various optional _\bm_\bo_\bd_\bi_\bf_\bi_\be_\br_\bs are avail-
+ in the same fashion as when reading input, so that several _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\b-
+ _\bt_\be_\br-separated words surrounded by quotes are considered one word. The
+ _\be_\bv_\be_\bn_\bt _\bd_\be_\bs_\bi_\bg_\bn_\ba_\bt_\bo_\br selects the event, the optional _\bw_\bo_\br_\bd _\bd_\be_\bs_\bi_\bg_\bn_\ba_\bt_\bo_\br se-
+ lects words from the event, and various optional _\bm_\bo_\bd_\bi_\bf_\bi_\be_\br_\bs are avail-
able to manipulate the selected words.
- History expansions are introduced by the appearance of the history ex-
- pansion character, which is !\b! by default. History expansions may ap-
+ History expansions are introduced by the appearance of the history ex-
+ pansion character, which is !\b! by default. History expansions may ap-
pear anywhere in the input, but do not nest.
- Only backslash (\\b\) and single quotes can quote the history expansion
- character, but the history expansion character is also treated as
+ Only backslash (\\b\) and single quotes can quote the history expansion
+ character, but the history expansion character is also treated as
quoted if it immediately precedes the closing double quote in a double-
quoted string.
defined above.
There is a special abbreviation for substitution, active when the _\bq_\bu_\bi_\bc_\bk
- _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn character (described above under h\bhi\bis\bst\btc\bch\bha\bar\brs\bs) is the first
+ _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn character (described above under h\bhi\bis\bst\btc\bch\bha\bar\brs\bs) is the first
character on the line. It selects the previous history entry, using an
event designator equivalent to !\b!!\b!, and substitutes one string for an-
other in that line. It is described below under E\bEv\bve\ben\bnt\bt D\bDe\bes\bsi\big\bgn\bna\bat\bto\bor\brs\bs.
This is the only history expansion that does not begin with the history
expansion character.
- Several shell options settable with the s\bsh\bho\bop\bpt\bt builtin may be used to
- tailor the behavior of history expansion. If the h\bhi\bis\bst\btv\bve\ber\bri\bif\bfy\by shell op-
- tion is enabled (see the description of the s\bsh\bho\bop\bpt\bt builtin below), and
- r\bre\bea\bad\bdl\bli\bin\bne\be is being used, history substitutions are not immediately
- passed to the shell parser. Instead, the expanded line is reloaded
+ Several shell options settable with the s\bsh\bho\bop\bpt\bt builtin may be used to
+ tailor the behavior of history expansion. If the h\bhi\bis\bst\btv\bve\ber\bri\bif\bfy\by shell op-
+ tion is enabled (see the description of the s\bsh\bho\bop\bpt\bt builtin below), and
+ r\bre\bea\bad\bdl\bli\bin\bne\be is being used, history substitutions are not immediately
+ passed to the shell parser. Instead, the expanded line is reloaded
into the r\bre\bea\bad\bdl\bli\bin\bne\be editing buffer for further modification. If r\bre\bea\bad\bdl\bli\bin\bne\be
is being used, and the h\bhi\bis\bst\btr\bre\bee\bed\bdi\bit\bt shell option is enabled, a failed
history substitution will be reloaded into the r\bre\bea\bad\bdl\bli\bin\bne\be editing buffer
for correction. The -\b-p\bp option to the h\bhi\bis\bst\bto\bor\bry\by builtin command may be
used to see what a history expansion will do before using it. The -\b-s\bs
option to the h\bhi\bis\bst\bto\bor\bry\by builtin may be used to add commands to the end of
- the history list without actually executing them, so that they are
+ the history list without actually executing them, so that they are
available for subsequent recall.
- The shell allows control of the various characters used by the history
+ The shell allows control of the various characters used by the history
expansion mechanism (see the description of h\bhi\bis\bst\btc\bch\bha\bar\brs\bs above under S\bSh\bhe\bel\bll\bl
V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs). The shell uses the history comment character to mark his-
tory timestamps when writing the history file.
is enabled using the s\bsh\bho\bop\bpt\bt builtin).
!\b!_\bn Refer to command line _\bn.
!\b!-\b-_\bn Refer to the current command minus _\bn.
- !\b!!\b! Refer to the previous command. This is a synonym for `!-1'.
+ !\b!!\b! Refer to the previous command. This is a synonym for "!-1".
!\b!_\bs_\bt_\br_\bi_\bn_\bg
Refer to the most recent command preceding the current position
in the history list starting with _\bs_\bt_\br_\bi_\bn_\bg.
used; it is an error if there is no previous search string.
^\b^_\bs_\bt_\br_\bi_\bn_\bg_\b1^\b^_\bs_\bt_\br_\bi_\bn_\bg_\b2^\b^
Quick substitution. Repeat the previous command, replacing
- _\bs_\bt_\br_\bi_\bn_\bg_\b1 with _\bs_\bt_\br_\bi_\bn_\bg_\b2. Equivalent to ``!!:s^_\bs_\bt_\br_\bi_\bn_\bg_\b1^_\bs_\bt_\br_\bi_\bn_\bg_\b2^''
+ _\bs_\bt_\br_\bi_\bn_\bg_\b1 with _\bs_\bt_\br_\bi_\bn_\bg_\b2. Equivalent to "!!:s^_\bs_\bt_\br_\bi_\bn_\bg_\b1^_\bs_\bt_\br_\bi_\bn_\bg_\b2^"
(see M\bMo\bod\bdi\bif\bfi\bie\ber\brs\bs below).
!\b!#\b# The entire command line typed so far.
^\b^ The first argument. That is, word 1.
$\b$ The last word. This is usually the last argument, but will ex-
pand to the zeroth word if there is only one word in the line.
- %\b% The first word matched by the most recent `?_\bs_\bt_\br_\bi_\bn_\bg?' search, if
- the search string begins with a character that is part of a
+ %\b% The first word matched by the most recent "?_\bs_\bt_\br_\bi_\bn_\bg?'" search,
+ if the search string begins with a character that is part of a
word.
- _\bx-\b-_\by A range of words; `-_\by' abbreviates `0-_\by'.
- *\b* All of the words but the zeroth. This is a synonym for `_\b1_\b-_\b$'.
+ _\bx-\b-_\by A range of words; "-_\by" abbreviates "0-_\by".
+ *\b* All of the words but the zeroth. This is a synonym for "_\b1_\b-_\b$".
It is not an error to use *\b* if there is just one word in the
event; the empty string is returned in that case.
x\bx*\b* Abbreviates _\bx_\b-_\b$.
x\bx-\b- Abbreviates _\bx_\b-_\b$ like x\bx*\b*, but omits the last word. If x\bx is miss-
ing, it defaults to 0.
- If a word designator is supplied without an event specification, the
+ If a word designator is supplied without an event specification, the
previous command is used as the event.
M\bMo\bod\bdi\bif\bfi\bie\ber\brs\bs
- After the optional word designator, there may appear a sequence of one
- or more of the following modifiers, each preceded by a `:'. These mod-
+ After the optional word designator, there may appear a sequence of one
+ or more of the following modifiers, each preceded by a ":". These mod-
ify, or edit, the word or words selected from the history event.
h\bh Remove a trailing filename component, leaving only the head.
s\bs/\b/_\bo_\bl_\bd/\b/_\bn_\be_\bw/\b/
Substitute _\bn_\be_\bw for the first occurrence of _\bo_\bl_\bd in the event
line. Any character may be used as the delimiter in place of /.
- The final delimiter is optional if it is the last character of
+ The final delimiter is optional if it is the last character of
the event line. The delimiter may be quoted in _\bo_\bl_\bd and _\bn_\be_\bw with
a single backslash. If & appears in _\bn_\be_\bw, it is replaced by _\bo_\bl_\bd.
- A single backslash will quote the &. If _\bo_\bl_\bd is null, it is set
- to the last _\bo_\bl_\bd substituted, or, if no previous history substi-
- tutions took place, the last _\bs_\bt_\br_\bi_\bn_\bg in a !\b!?\b?_\bs_\bt_\br_\bi_\bn_\bg[\b[?\b?]\b] search.
+ A single backslash will quote the &. If _\bo_\bl_\bd is null, it is set
+ to the last _\bo_\bl_\bd substituted, or, if no previous history substi-
+ tutions took place, the last _\bs_\bt_\br_\bi_\bn_\bg in a !\b!?\b?_\bs_\bt_\br_\bi_\bn_\bg[\b[?\b?]\b] search.
If _\bn_\be_\bw is null, each matching _\bo_\bl_\bd is deleted.
&\b& Repeat the previous substitution.
g\bg Cause changes to be applied over the entire event line. This is
- used in conjunction with `:\b:s\bs' (e.g., `:\b:g\bgs\bs/\b/_\bo_\bl_\bd/\b/_\bn_\be_\bw/\b/') or `:\b:&\b&'.
- If used with `:\b:s\bs', any delimiter can be used in place of /, and
+ used in conjunction with ":\b:s\bs" (e.g., ":\b:g\bgs\bs/\b/_\bo_\bl_\bd/\b/_\bn_\be_\bw/\b/") or ":\b:&\b&".
+ If used with ":\b:s\bs", any delimiter can be used in place of /, and
the final delimiter is optional if it is the last character of
the event line. An a\ba may be used as a synonym for g\bg.
- G\bG Apply the following `s\bs' or `&\b&' modifier once to each word in the
+ G\bG Apply the following "s\bs" or "&\b&" modifier once to each word in the
event line.
S\bSH\bHE\bEL\bLL\bL B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
are not specified as accepting options interpret arguments beginning
with -\b- as invalid options and require -\b--\b- to prevent this interpreta-
tion.
+
:\b: [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
No effect; the command does nothing beyond expanding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
and performing any specified redirections. The return status is
zero.
- .\b. _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
+ .\b. _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
s\bso\bou\bur\brc\bce\be _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
Read and execute commands from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be in the current shell en-
vironment and return the exit status of the last command exe-
cuted from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be. If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not contain a slash,
filenames in P\bPA\bAT\bTH\bH are used to find the directory containing
_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, but _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not need to be executable. The file
- searched for in P\bPA\bAT\bTH\bH need not be executable. When b\bba\bas\bsh\bh is not
- in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it searches the current directory if no file is
- found in P\bPA\bAT\bTH\bH. If the s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh option to the s\bsh\bho\bop\bpt\bt builtin
- command is turned off, the P\bPA\bAT\bTH\bH is not searched. If any _\ba_\br_\bg_\bu_\b-
- _\bm_\be_\bn_\bt_\bs are supplied, they become the positional parameters when
- _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is executed. Otherwise the positional parameters are
- unchanged. If the -\b-T\bT option is enabled, .\b. inherits any trap on
+ searched for in P\bPA\bAT\bTH\bH need not be executable. When b\bba\bas\bsh\bh is not
+ in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it searches the current directory if no file is
+ found in P\bPA\bAT\bTH\bH. If the s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh option to the s\bsh\bho\bop\bpt\bt builtin
+ command is turned off, the P\bPA\bAT\bTH\bH is not searched. If any _\ba_\br_\bg_\bu_\b-
+ _\bm_\be_\bn_\bt_\bs are supplied, they become the positional parameters when
+ _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is executed. Otherwise the positional parameters are
+ unchanged. If the -\b-T\bT option is enabled, .\b. inherits any trap on
D\bDE\bEB\bBU\bUG\bG; if it is not, any D\bDE\bEB\bBU\bUG\bG trap string is saved and restored
around the call to .\b., and .\b. unsets the D\bDE\bEB\bBU\bUG\bG trap while it exe-
cutes. If -\b-T\bT is not set, and the sourced file changes the D\bDE\bEB\bBU\bUG\bG
- trap, the new value is retained when .\b. completes. The return
- status is the status of the last command exited within the
+ trap, the new value is retained when .\b. completes. The return
+ status is the status of the last command exited within the
script (0 if no commands are executed), and false if _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is
not found or cannot be read.
a\bal\bli\bia\bas\bs [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
A\bAl\bli\bia\bas\bs with no arguments or with the -\b-p\bp option prints the list of
- aliases in the form a\bal\bli\bia\bas\bs _\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be on standard output. When
- arguments are supplied, an alias is defined for each _\bn_\ba_\bm_\be whose
- _\bv_\ba_\bl_\bu_\be is given. A trailing space in _\bv_\ba_\bl_\bu_\be causes the next word
+ aliases in the form a\bal\bli\bia\bas\bs _\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be on standard output. When
+ arguments are supplied, an alias is defined for each _\bn_\ba_\bm_\be whose
+ _\bv_\ba_\bl_\bu_\be is given. A trailing space in _\bv_\ba_\bl_\bu_\be causes the next word
to be checked for alias substitution when the alias is expanded.
For each _\bn_\ba_\bm_\be in the argument list for which no _\bv_\ba_\bl_\bu_\be is sup-
plied, the name and value of the alias is printed. A\bAl\bli\bia\bas\bs re-
b\bbg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc ...]
Resume each suspended job _\bj_\bo_\bb_\bs_\bp_\be_\bc in the background, as if it
had been started with &\b&. If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's
- notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used. b\bbg\bg _\bj_\bo_\bb_\bs_\bp_\be_\bc returns 0 unless
- run when job control is disabled or, when run with job control
- enabled, any specified _\bj_\bo_\bb_\bs_\bp_\be_\bc was not found or was started
+ notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used. b\bbg\bg _\bj_\bo_\bb_\bs_\bp_\be_\bc returns 0 unless
+ run when job control is disabled or, when run with job control
+ enabled, any specified _\bj_\bo_\bb_\bs_\bp_\be_\bc was not found or was started
without job control.
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] [-\b-l\blp\bps\bsv\bvP\bPS\bSV\bVX\bX]
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] _\bk_\be_\by_\bs_\be_\bq:_\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] _\bk_\be_\by_\bs_\be_\bq:_\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
b\bbi\bin\bnd\bd _\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b-_\bl_\bi_\bn_\be
- Display current r\bre\bea\bad\bdl\bli\bin\bne\be key and function bindings, bind a key
- sequence to a r\bre\bea\bad\bdl\bli\bin\bne\be function or macro, or set a r\bre\bea\bad\bdl\bli\bin\bne\be
+ Display current r\bre\bea\bad\bdl\bli\bin\bne\be key and function bindings, bind a key
+ sequence to a r\bre\bea\bad\bdl\bli\bin\bne\be function or macro, or set a r\bre\bea\bad\bdl\bli\bin\bne\be
variable. Each non-option argument is a command as it would ap-
pear in a r\bre\bea\bad\bdl\bli\bin\bne\be initialization file such as _\b._\bi_\bn_\bp_\bu_\bt_\br_\bc, but
each binding or command must be passed as a separate argument;
_\bm_\ba_\bn_\bd is executed, the shell sets the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_L\bLI\bIN\bNE\bE vari-
able to the contents of the r\bre\bea\bad\bdl\bli\bin\bne\be line buffer and the
R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT and R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_M\bMA\bAR\bRK\bK variables to the current
- location of the insertion point and the saved insertion
- point (the mark), respectively. The shell assigns any
- numeric argument the user supplied to the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_A\bAR\bRG\bGU\bU-\b-
- M\bME\bEN\bNT\bT variable. If there was no argument, that variable
+ location of the insertion point and the saved insertion
+ point (the mark), respectively. The shell assigns any
+ numeric argument the user supplied to the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_A\bAR\bRG\bGU\bU-\b-
+ M\bME\bEN\bNT\bT variable. If there was no argument, that variable
is not set. If the executed command changes the value of
any of R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_L\bLI\bIN\bNE\bE, R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT, or R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_M\bMA\bAR\bRK\bK,
those new values will be reflected in the editing state.
associated commands in a format that can be reused as in-
put.
- The return value is 0 unless an unrecognized option is given or
+ The return value is 0 unless an unrecognized option is given or
an error occurred.
b\bbr\bre\bea\bak\bk [_\bn]
- Exit from within a f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or s\bse\bel\ble\bec\bct\bt loop. If _\bn is
- specified, break _\bn levels. _\bn must be >= 1. If _\bn is greater
- than the number of enclosing loops, all enclosing loops are ex-
- ited. The return value is 0 unless _\bn is not greater than or
+ Exit from within a f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or s\bse\bel\ble\bec\bct\bt loop. If _\bn is
+ specified, break _\bn levels. _\bn must be >= 1. If _\bn is greater
+ than the number of enclosing loops, all enclosing loops are ex-
+ ited. The return value is 0 unless _\bn is not greater than or
equal to 1.
b\bbu\bui\bil\blt\bti\bin\bn _\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
- Execute the specified shell builtin, passing it _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs, and
+ Execute the specified shell builtin, passing it _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs, and
return its exit status. This is useful when defining a function
whose name is the same as a shell builtin, retaining the func-
tionality of the builtin within the function. The c\bcd\bd builtin is
- commonly redefined this way. The return status is false if
+ commonly redefined this way. The return status is false if
_\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn is not a shell builtin command.
c\bca\bal\bll\ble\ber\br [_\be_\bx_\bp_\br]
out _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number and source filename of
the current subroutine call. If a non-negative integer is sup-
plied as _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number, subroutine name,
- and source file corresponding to that position in the current
- execution call stack. This extra information may be used, for
- example, to print a stack trace. The current frame is frame 0.
- The return value is 0 unless the shell is not executing a sub-
- routine call or _\be_\bx_\bp_\br does not correspond to a valid position in
+ and source file corresponding to that position in the current
+ execution call stack. This extra information may be used, for
+ example, to print a stack trace. The current frame is frame 0.
+ The return value is 0 unless the shell is not executing a sub-
+ routine call or _\be_\bx_\bp_\br does not correspond to a valid position in
the call stack.
c\bcd\bd [-\b-L\bL|[-\b-P\bP [-\b-e\be]]] [-@] [_\bd_\bi_\br]
- Change the current directory to _\bd_\bi_\br. if _\bd_\bi_\br is not supplied,
- the value of the H\bHO\bOM\bME\bE shell variable is the default. The vari-
+ Change the current directory to _\bd_\bi_\br. if _\bd_\bi_\br is not supplied,
+ the value of the H\bHO\bOM\bME\bE shell variable is the default. The vari-
able C\bCD\bDP\bPA\bAT\bTH\bH defines the search path for the directory containing
- _\bd_\bi_\br: each directory name in C\bCD\bDP\bPA\bAT\bTH\bH is searched for _\bd_\bi_\br. Alter-
- native directory names in C\bCD\bDP\bPA\bAT\bTH\bH are separated by a colon (:).
- A null directory name in C\bCD\bDP\bPA\bAT\bTH\bH is the same as the current di-
- rectory, i.e., ``.\b.''. If _\bd_\bi_\br begins with a slash (/), then C\bCD\bD-\b-
- P\bPA\bAT\bTH\bH is not used. The -\b-P\bP option causes c\bcd\bd to use the physical
+ _\bd_\bi_\br: the shell searches each directory name in C\bCD\bDP\bPA\bAT\bTH\bH for _\bd_\bi_\br.
+ Alternative directory names in C\bCD\bDP\bPA\bAT\bTH\bH are separated by a colon
+ (:). A null directory name in C\bCD\bDP\bPA\bAT\bTH\bH is the same as the current
+ directory, i.e., ".". If _\bd_\bi_\br begins with a slash (/), then C\bCD\bD-\b-
+ P\bPA\bAT\bTH\bH is not used. The -\b-P\bP option causes c\bcd\bd to use the physical
directory structure by resolving symbolic links while traversing
_\bd_\bi_\br and before processing instances of _\b._\b. in _\bd_\bi_\br (see also the
-\b-P\bP option to the s\bse\bet\bt builtin command); the -\b-L\bL option forces sym-
- bolic links to be followed by resolving the link after process-
- ing instances of _\b._\b. in _\bd_\bi_\br. If _\b._\b. appears in _\bd_\bi_\br, it is pro-
- cessed by removing the immediately previous pathname component
- from _\bd_\bi_\br, back to a slash or the beginning of _\bd_\bi_\br. If the -\b-e\be
- option is supplied with -\b-P\bP, and the current working directory
+ bolic links to be followed by resolving the link after process-
+ ing instances of _\b._\b. in _\bd_\bi_\br. If _\b._\b. appears in _\bd_\bi_\br, it is
+ processed by removing the immediately previous pathname compo-
+ nent from _\bd_\bi_\br, back to a slash or the beginning of _\bd_\bi_\br. If the
+ -\b-e\be option is supplied with -\b-P\bP, and the current working directory
cannot be successfully determined after a successful directory
change, c\bcd\bd will return an unsuccessful status. On systems that
support it, the -\b-@\b@ option presents the extended attributes asso-
- ciated with a file as a directory. An argument of -\b- is con-
- verted to $\b$O\bOL\bLD\bDP\bPW\bWD\bD before the directory change is attempted. If
- a non-empty directory name from C\bCD\bDP\bPA\bAT\bTH\bH is used, or if -\b- is the
- first argument, and the directory change is successful, the ab-
- solute pathname of the new working directory is written to the
+ ciated with a file as a directory. An argument of -\b- is con-
+ verted to $\b$O\bOL\bLD\bDP\bPW\bWD\bD before the directory change is attempted. If
+ a non-empty directory name from C\bCD\bDP\bPA\bAT\bTH\bH is used, or if -\b- is the
+ first argument, and the directory change is successful, the ab-
+ solute pathname of the new working directory is written to the
standard output. If the directory change is successful, c\bcd\bd sets
the value of the P\bPW\bWD\bD environment variable to the new directory
name, and sets the O\bOL\bLD\bDP\bPW\bWD\bD environment variable to the value of
c\bco\bom\bmm\bma\ban\bnd\bd [-\b-p\bpV\bVv\bv] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\ba_\br_\bg ...]
Run _\bc_\bo_\bm_\bm_\ba_\bn_\bd with _\ba_\br_\bg_\bs suppressing the normal shell function
lookup. Only builtin commands or commands found in the P\bPA\bAT\bTH\bH are
- executed. If the -\b-p\bp option is given, the search for _\bc_\bo_\bm_\bm_\ba_\bn_\bd is
- performed using a default value for P\bPA\bAT\bTH\bH that is guaranteed to
- find all of the standard utilities. If either the -\b-V\bV or -\b-v\bv op-
- tion is supplied, a description of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is printed. The -\b-v\bv
- option causes a single word indicating the command or filename
+ executed. If the -\b-p\bp option is given, the search for _\bc_\bo_\bm_\bm_\ba_\bn_\bd is
+ performed using a default value for P\bPA\bAT\bTH\bH that is guaranteed to
+ find all of the standard utilities. If either the -\b-V\bV or -\b-v\bv op-
+ tion is supplied, a description of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is printed. The -\b-v\bv
+ option causes a single word indicating the command or filename
used to invoke _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be displayed; the -\b-V\bV option produces a
more verbose description. If the -\b-V\bV or -\b-v\bv option is supplied,
the exit status is 0 if _\bc_\bo_\bm_\bm_\ba_\bn_\bd was found, and 1 if not. If
neither option is supplied and an error occurred or _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
- not be found, the exit status is 127. Otherwise, the exit sta-
+ not be found, the exit status is 127. Otherwise, the exit sta-
tus of the c\bco\bom\bmm\bma\ban\bnd\bd builtin is the exit status of _\bc_\bo_\bm_\bm_\ba_\bn_\bd.
c\bco\bom\bmp\bpg\bge\ben\bn [-\b-V\bV _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bw_\bo_\br_\bd]
- Generate possible completion matches for _\bw_\bo_\br_\bd according to the
- _\bo_\bp_\bt_\bi_\bo_\bns, which may be any option accepted by the c\bco\bom\bmp\bpl\ble\bet\bte\be
+ Generate possible completion matches for _\bw_\bo_\br_\bd according to the
+ _\bo_\bp_\bt_\bi_\bo_\bns, which may be any option accepted by the c\bco\bom\bmp\bpl\ble\bet\bte\be
builtin with the exceptions of -\b-p\bp, -\b-r\br, -\b-D\bD, -\b-E\bE, and -\b-I\bI, and write
the matches to the standard output. If the -\b-V\bV option is sup-
plied, c\bco\bom\bmp\bpg\bge\ben\bn stores the generated completions into the indexed
- array variable _\bv_\ba_\br_\bn_\ba_\bm_\be instead of writing them to the standard
- output. When using the -\b-F\bF or -\b-C\bC options, the various shell
- variables set by the programmable completion facilities, while
+ array variable _\bv_\ba_\br_\bn_\ba_\bm_\be instead of writing them to the standard
+ output. When using the -\b-F\bF or -\b-C\bC options, the various shell
+ variables set by the programmable completion facilities, while
available, will not have useful values.
The matches will be generated in the same way as if the program-
mable completion code had generated them directly from a comple-
- tion specification with the same flags. If _\bw_\bo_\br_\bd is specified,
+ tion specification with the same flags. If _\bw_\bo_\br_\bd is specified,
only those completions matching _\bw_\bo_\br_\bd will be displayed.
- The return value is true unless an invalid option is supplied,
+ The return value is true unless an invalid option is supplied,
or no matches were generated.
c\bco\bom\bmp\bpl\ble\bet\bte\be [-\b-a\bab\bbc\bcd\bde\bef\bfg\bgj\bjk\bks\bsu\buv\bv] [-\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bEI\bI] [-\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn]
[-\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt] [-\b-W\bW _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt] [-\b-F\bF _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn] [-\b-C\bC _\bc_\bo_\bm_\bm_\ba_\bn_\bd]
- [-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt] [-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx] [-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be _\b._\b._\b.]
+ [-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt] [-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx] [-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
c\bco\bom\bmp\bpl\ble\bet\bte\be -\b-p\bpr\br [-\b-D\bDE\bEI\bI] [_\bn_\ba_\bm_\be ...]
- Specify how arguments to each _\bn_\ba_\bm_\be should be completed. If the
- -\b-p\bp option is supplied, or if no options are supplied, existing
- completion specifications are printed in a way that allows them
- to be reused as input. The -\b-r\br option removes a completion spec-
- ification for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are supplied, all com-
- pletion specifications. The -\b-D\bD option indicates that other sup-
- plied options and actions should apply to the ``default'' com-
- mand completion; that is, completion attempted on a command for
- which no completion has previously been defined. The -\b-E\bE option
- indicates that other supplied options and actions should apply
- to ``empty'' command completion; that is, completion attempted
- on a blank line. The -\b-I\bI option indicates that other supplied
- options and actions should apply to completion on the initial
- non-assignment word on the line, or after a command delimiter
- such as ;\b; or |\b|, which is usually command name completion. If
- multiple options are supplied, the -\b-D\bD option takes precedence
- over -\b-E\bE, and both take precedence over -\b-I\bI. If any of -\b-D\bD, -\b-E\bE, or
- -\b-I\bI are supplied, any other _\bn_\ba_\bm_\be arguments are ignored; these
- completions only apply to the case specified by the option.
+ Specify how arguments to each _\bn_\ba_\bm_\be should be completed. If the
+ -\b-p\bp option is supplied, or if no options or _\bn_\ba_\bm_\bes are supplied,
+ existing completion specifications are printed in a way that al-
+ lows them to be reused as input. The -\b-r\br option removes a com-
+ pletion specification for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are sup-
+ plied, all completion specifications. The -\b-D\bD option indicates
+ that other supplied options and actions should apply to the "de-
+ fault" command completion; that is, completion attempted on a
+ command for which no completion has previously been defined.
+ The -\b-E\bE option indicates that other supplied options and actions
+ should apply to "empty" command completion; that is, completion
+ attempted on a blank line. The -\b-I\bI option indicates that other
+ supplied options and actions should apply to completion on the
+ initial non-assignment word on the line, or after a command de-
+ limiter such as ;\b; or |\b|, which is usually command name comple-
+ tion. If multiple options are supplied, the -\b-D\bD option takes
+ precedence over -\b-E\bE, and both take precedence over -\b-I\bI. If any of
+ -\b-D\bD, -\b-E\bE, or -\b-I\bI are supplied, any other _\bn_\ba_\bm_\be arguments are ig-
+ nored; these completions only apply to the case specified by the
+ option.
The process of applying these completion specifications when
- word completion is attempted is described above under P\bPr\bro\bog\bgr\bra\bam\bm-\b-
- m\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn.
+ word completion is attempted is described above under P\bPr\bro\bog\bgr\bra\bam\bmm\bma\ba-\b-
+ b\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn.
- Other options, if specified, have the following meanings. The
- arguments to the -\b-G\bG, -\b-W\bW, and -\b-X\bX options (and, if necessary, the
- -\b-P\bP and -\b-S\bS options) should be quoted to protect them from expan-
+ Other options, if specified, have the following meanings. The
+ arguments to the -\b-G\bG, -\b-W\bW, and -\b-X\bX options (and, if necessary, the
+ -\b-P\bP and -\b-S\bS options) should be quoted to protect them from expan-
sion before the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin is invoked.
-\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn
- The _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn controls several aspects of the comp-
- spec's behavior beyond the simple generation of comple-
+ The _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn controls several aspects of the comp-
+ spec's behavior beyond the simple generation of comple-
tions. _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn may be one of:
b\bba\bas\bsh\bhd\bde\bef\bfa\bau\bul\blt\bt
Perform the rest of the default b\bba\bas\bsh\bh completions
tempted and any matches are added to the results
of the other actions.
-\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn
- The _\ba_\bc_\bt_\bi_\bo_\bn may be one of the following to generate a
+ The _\ba_\bc_\bt_\bi_\bo_\bn may be one of the following to generate a
list of possible completions:
a\bal\bli\bia\bas\bs Alias names. May also be specified as -\b-a\ba.
a\bar\brr\bra\bay\byv\bva\bar\br
Array variable names.
b\bbi\bin\bnd\bdi\bin\bng\bg R\bRe\bea\bad\bdl\bli\bin\bne\be key binding names.
- b\bbu\bui\bil\blt\bti\bin\bn Names of shell builtin commands. May also be
+ b\bbu\bui\bil\blt\bti\bin\bn Names of shell builtin commands. May also be
specified as -\b-b\bb.
c\bco\bom\bmm\bma\ban\bnd\bd Command names. May also be specified as -\b-c\bc.
d\bdi\bir\bre\bec\bct\bto\bor\bry\by
d\bdi\bis\bsa\bab\bbl\ble\bed\bd
Names of disabled shell builtins.
e\ben\bna\bab\bbl\ble\bed\bd Names of enabled shell builtins.
- e\bex\bxp\bpo\bor\brt\bt Names of exported shell variables. May also be
+ e\bex\bxp\bpo\bor\brt\bt Names of exported shell variables. May also be
specified as -\b-e\be.
f\bfi\bil\ble\be File names. May also be specified as -\b-f\bf.
f\bfu\bun\bnc\bct\bti\bio\bon\bn
h\bhe\bel\blp\bpt\bto\bop\bpi\bic\bc
Help topics as accepted by the h\bhe\bel\blp\bp builtin.
h\bho\bos\bst\btn\bna\bam\bme\be
- Hostnames, as taken from the file specified by
+ Hostnames, as taken from the file specified by
the H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE shell variable.
- j\bjo\bob\bb Job names, if job control is active. May also
+ j\bjo\bob\bb Job names, if job control is active. May also
be specified as -\b-j\bj.
- k\bke\bey\byw\bwo\bor\brd\bd Shell reserved words. May also be specified as
+ k\bke\bey\byw\bwo\bor\brd\bd Shell reserved words. May also be specified as
-\b-k\bk.
r\bru\bun\bnn\bni\bin\bng\bg Names of running jobs, if job control is active.
s\bse\ber\brv\bvi\bic\bce\be Service names. May also be specified as -\b-s\bs.
- s\bse\bet\bto\bop\bpt\bt Valid arguments for the -\b-o\bo option to the s\bse\bet\bt
+ s\bse\bet\bto\bop\bpt\bt Valid arguments for the -\b-o\bo option to the s\bse\bet\bt
builtin.
- s\bsh\bho\bop\bpt\bt Shell option names as accepted by the s\bsh\bho\bop\bpt\bt
+ s\bsh\bho\bop\bpt\bt Shell option names as accepted by the s\bsh\bho\bop\bpt\bt
builtin.
s\bsi\big\bgn\bna\bal\bl Signal names.
s\bst\bto\bop\bpp\bpe\bed\bd Names of stopped jobs, if job control is active.
first argument ($\b$1\b1) is the name of the command whose ar-
guments are being completed, the second argument ($\b$2\b2) is
the word being completed, and the third argument ($\b$3\b3) is
- the word preceding the word being completed on the cur-
- rent command line. When it finishes, the possible com-
- pletions are retrieved from the value of the C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY
+ the word preceding the word being completed on the cur-
+ rent command line. When it finishes, the possible com-
+ pletions are retrieved from the value of the C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY
array variable.
-\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt
- The pathname expansion pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
+ The pathname expansion pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
generate the possible completions.
-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx
- _\bp_\br_\be_\bf_\bi_\bx is added at the beginning of each possible com-
+ _\bp_\br_\be_\bf_\bi_\bx is added at the beginning of each possible com-
pletion after all other options have been applied.
-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx
_\bs_\bu_\bf_\bf_\bi_\bx is appended to each possible completion after all
special variable as delimiters, and each resultant word
is expanded. Shell quoting is honored within _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt,
in order to provide a mechanism for the words to contain
- shell metacharacters or characters in the value of I\bIF\bFS\bS.
- The possible completions are the members of the resul-
+ shell metacharacters or characters in the value of I\bIF\bFS\bS.
+ The possible completions are the members of the resul-
tant list which match the word being completed.
-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt
- _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for pathname expansion.
+ _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for pathname expansion.
It is applied to the list of possible completions gener-
ated by the preceding options and arguments, and each
completion matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed from the list.
The return value is true unless an invalid option is supplied,
an option other than -\b-p\bp, -\b-r\br, -\b-D\bD, -\b-E\bE, or -\b-I\bI is supplied without a
- _\bn_\ba_\bm_\be argument, an attempt is made to remove a completion speci-
+ _\bn_\ba_\bm_\be argument, an attempt is made to remove a completion speci-
fication for a _\bn_\ba_\bm_\be for which no specification exists, or an er-
ror occurs adding a completion specification.
c\bco\bom\bmp\bpo\bop\bpt\bt [-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bEI\bI] [+\b+o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be]
Modify completion options for each _\bn_\ba_\bm_\be according to the _\bo_\bp_\b-
_\bt_\bi_\bo_\bns, or for the currently-executing completion if no _\bn_\ba_\bm_\bes are
- supplied. If no _\bo_\bp_\bt_\bi_\bo_\bns are given, display the completion op-
- tions for each _\bn_\ba_\bm_\be or the current completion. The possible
- values of _\bo_\bp_\bt_\bi_\bo_\bn are those valid for the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin de-
- scribed above. The -\b-D\bD option indicates that other supplied op-
- tions should apply to the ``default'' command completion; that
- is, completion attempted on a command for which no completion
- has previously been defined. The -\b-E\bE option indicates that other
- supplied options should apply to ``empty'' command completion;
+ supplied. If no _\bo_\bp_\bt_\bi_\bo_\bns are given, display the completion op-
+ tions for each _\bn_\ba_\bm_\be or the current completion. The possible
+ values of _\bo_\bp_\bt_\bi_\bo_\bn are those valid for the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin de-
+ scribed above. The -\b-D\bD option indicates that other supplied op-
+ tions should apply to the "default" command completion; that is,
+ completion attempted on a command for which no completion has
+ previously been defined. The -\b-E\bE option indicates that other
+ supplied options should apply to "empty" command completion;
that is, completion attempted on a blank line. The -\b-I\bI option
indicates that other supplied options should apply to completion
- on the initial non-assignment word on the line, or after a com-
- mand delimiter such as ;\b; or |\b|, which is usually command name
+ on the initial non-assignment word on the line, or after a com-
+ mand delimiter such as ;\b; or |\b|, which is usually command name
completion.
- The return value is true unless an invalid option is supplied,
+ The return value is true unless an invalid option is supplied,
an attempt is made to modify the options for a _\bn_\ba_\bm_\be for which no
completion specification exists, or an output error occurs.
c\bco\bon\bnt\bti\bin\bnu\bue\be [_\bn]
Resume the next iteration of the enclosing f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or
- s\bse\bel\ble\bec\bct\bt loop. If _\bn is specified, resume at the _\bnth enclosing
- loop. _\bn must be >= 1. If _\bn is greater than the number of en-
- closing loops, the last enclosing loop (the ``top-level'' loop)
- is resumed. The return value is 0 unless _\bn is not greater than
- or equal to 1.
+ s\bse\bel\ble\bec\bct\bt loop. If _\bn is specified, resume at the _\bnth enclosing
+ loop. _\bn must be >= 1. If _\bn is greater than the number of en-
+ closing loops, the shell resumes the last enclosing loop (the
+ "top-level" loop). The return value is 0 unless _\bn is not
+ greater than or equal to 1.
d\bde\bec\bcl\bla\bar\bre\be [-\b-a\baA\bAf\bfF\bFg\bgi\biI\bIl\bln\bnr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
t\bty\byp\bpe\bes\bse\bet\bt [-\b-a\baA\bAf\bfF\bFg\bgi\biI\bIl\bln\bnr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
- Declare variables and/or give them attributes. If no _\bn_\ba_\bm_\bes are
- given then display the values of variables. The -\b-p\bp option will
+ Declare variables and/or give them attributes. If no _\bn_\ba_\bm_\bes are
+ given then display the values of variables. The -\b-p\bp option will
display the attributes and values of each _\bn_\ba_\bm_\be. When -\b-p\bp is used
with _\bn_\ba_\bm_\be arguments, additional options, other than -\b-f\bf and -\b-F\bF,
are ignored. When -\b-p\bp is supplied without _\bn_\ba_\bm_\be arguments, it
will display the attributes and values of all variables having
the attributes specified by the additional options. If no other
- options are supplied with -\b-p\bp, d\bde\bec\bcl\bla\bar\bre\be will display the at-
- tributes and values of all shell variables. The -\b-f\bf option will
- restrict the display to shell functions. The -\b-F\bF option inhibits
- the display of function definitions; only the function name and
+ options are supplied with -\b-p\bp, d\bde\bec\bcl\bla\bar\bre\be will display the attrib-
+ utes and values of all shell variables. The -\b-f\bf option will re-
+ strict the display to shell functions. The -\b-F\bF option inhibits
+ the display of function definitions; only the function name and
attributes are printed. If the e\bex\bxt\btd\bde\beb\bbu\bug\bg shell option is enabled
using s\bsh\bho\bop\bpt\bt, the source file name and line number where each
_\bn_\ba_\bm_\be is defined are displayed as well. The -\b-F\bF option implies
tion. It is ignored in all other cases. The -\b-I\bI option causes
local variables to inherit the attributes (except the _\bn_\ba_\bm_\be_\br_\be_\bf
attribute) and value of any existing variable with the same _\bn_\ba_\bm_\be
- at a surrounding scope. If there is no existing variable, the
+ at a surrounding scope. If there is no existing variable, the
local variable is initially unset. The following options can be
- used to restrict output to variables with the specified attri-
- bute or to give variables attributes:
+ used to restrict output to variables with the specified at-
+ tribute or to give variables attributes:
-\b-a\ba Each _\bn_\ba_\bm_\be is an indexed array variable (see A\bAr\brr\bra\bay\bys\bs
above).
-\b-A\bA Each _\bn_\ba_\bm_\be is an associative array variable (see A\bAr\brr\bra\bay\bys\bs
above).
-\b-f\bf Use function names only.
-\b-i\bi The variable is treated as an integer; arithmetic evalua-
- tion (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN above) is performed when
+ tion (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN above) is performed when
the variable is assigned a value.
- -\b-l\bl When the variable is assigned a value, all upper-case
- characters are converted to lower-case. The upper-case
+ -\b-l\bl When the variable is assigned a value, all upper-case
+ characters are converted to lower-case. The upper-case
attribute is disabled.
- -\b-n\bn Give each _\bn_\ba_\bm_\be the _\bn_\ba_\bm_\be_\br_\be_\bf attribute, making it a name
- reference to another variable. That other variable is
- defined by the value of _\bn_\ba_\bm_\be. All references, assign-
- ments, and attribute modifications to _\bn_\ba_\bm_\be, except those
- using or changing the -\b-n\bn attribute itself, are performed
- on the variable referenced by _\bn_\ba_\bm_\be's value. The nameref
+ -\b-n\bn Give each _\bn_\ba_\bm_\be the _\bn_\ba_\bm_\be_\br_\be_\bf attribute, making it a name
+ reference to another variable. That other variable is
+ defined by the value of _\bn_\ba_\bm_\be. All references, assign-
+ ments, and attribute modifications to _\bn_\ba_\bm_\be, except those
+ using or changing the -\b-n\bn attribute itself, are performed
+ on the variable referenced by _\bn_\ba_\bm_\be's value. The nameref
attribute cannot be applied to array variables.
-\b-r\br Make _\bn_\ba_\bm_\bes readonly. These names cannot then be assigned
values by subsequent assignment statements or unset.
-\b-t\bt Give each _\bn_\ba_\bm_\be the _\bt_\br_\ba_\bc_\be attribute. Traced functions in-
- herit the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps from the calling shell.
+ herit the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps from the calling shell.
The trace attribute has no special meaning for variables.
- -\b-u\bu When the variable is assigned a value, all lower-case
- characters are converted to upper-case. The lower-case
+ -\b-u\bu When the variable is assigned a value, all lower-case
+ characters are converted to upper-case. The lower-case
attribute is disabled.
- -\b-x\bx Mark _\bn_\ba_\bm_\bes for export to subsequent commands via the en-
+ -\b-x\bx Mark _\bn_\ba_\bm_\bes for export to subsequent commands via the en-
vironment.
- Using `+' instead of `-' turns off the attribute instead, with
- the exceptions that +\b+a\ba and +\b+A\bA may not be used to destroy array
- variables and +\b+r\br will not remove the readonly attribute. When
+ Using "+" instead of "-" turns off the attribute instead, with
+ the exceptions that +\b+a\ba and +\b+A\bA may not be used to destroy array
+ variables and +\b+r\br will not remove the readonly attribute. When
used in a function, d\bde\bec\bcl\bla\bar\bre\be and t\bty\byp\bpe\bes\bse\bet\bt make each _\bn_\ba_\bm_\be local, as
with the l\blo\boc\bca\bal\bl command, unless the -\b-g\bg option is supplied. If a
variable name is followed by =_\bv_\ba_\bl_\bu_\be, the value of the variable
ment syntax to create array variables, additional attributes do
not take effect until subsequent assignments. The return value
is 0 unless an invalid option is encountered, an attempt is made
- to define a function using ``-f foo=bar'', an attempt is made to
+ to define a function using "-f foo=bar". an attempt is made to
assign a value to a readonly variable, an attempt is made to as-
sign a value to an array variable without using the compound as-
- signment syntax (see A\bAr\brr\bra\bay\bys\bs above), one of the _\bn_\ba_\bm_\be_\bs is not a
- valid shell variable name, an attempt is made to turn off read-
- only status for a readonly variable, an attempt is made to turn
+ signment syntax (see A\bAr\brr\bra\bay\bys\bs above), one of the _\bn_\ba_\bm_\be_\bs is not a
+ valid shell variable name, an attempt is made to turn off read-
+ only status for a readonly variable, an attempt is made to turn
off array status for an array variable, or an attempt is made to
display a non-existent function with -\b-f\bf.
list with the p\bpu\bus\bsh\bhd\bd command; the p\bpo\bop\bpd\bd command removes entries
from the list. The current directory is always the first direc-
tory in the stack.
- -\b-c\bc Clears the directory stack by deleting all of the en-
+ -\b-c\bc Clears the directory stack by deleting all of the en-
tries.
- -\b-l\bl Produces a listing using full pathnames; the default
+ -\b-l\bl Produces a listing using full pathnames; the default
listing format uses a tilde to denote the home directory.
-\b-p\bp Print the directory stack with one entry per line.
- -\b-v\bv Print the directory stack with one entry per line, pre-
+ -\b-v\bv Print the directory stack with one entry per line, pre-
fixing each entry with its index in the stack.
+\b+_\bn Displays the _\bnth entry counting from the left of the list
shown by d\bdi\bir\brs\bs when invoked without options, starting with
zero.
- -\b-_\bn Displays the _\bnth entry counting from the right of the
+ -\b-_\bn Displays the _\bnth entry counting from the right of the
list shown by d\bdi\bir\brs\bs when invoked without options, starting
with zero.
is given, each _\bj_\bo_\bb_\bs_\bp_\be_\bc is not removed from the table, but is
marked so that S\bSI\bIG\bGH\bHU\bUP\bP is not sent to the job if the shell re-
ceives a S\bSI\bIG\bGH\bHU\bUP\bP. If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is supplied, the -\b-a\ba option means
- to remove or mark all jobs; the -\b-r\br option without a _\bj_\bo_\bb_\bs_\bp_\be_\bc ar-
+ to remove or mark all jobs; the -\b-r\br option without a _\bj_\bo_\bb_\bs_\bp_\be_\bc ar-
gument restricts operation to running jobs. The return value is
0 unless a _\bj_\bo_\bb_\bs_\bp_\be_\bc does not specify a valid job.
Output the _\ba_\br_\bgs, separated by spaces, followed by a newline.
The return status is 0 unless a write error occurs. If -\b-n\bn is
specified, the trailing newline is suppressed. If the -\b-e\be option
- is given, interpretation of the following backslash-escaped
- characters is enabled. The -\b-E\bE option disables the interpreta-
- tion of these escape characters, even on systems where they are
- interpreted by default. The x\bxp\bpg\bg_\b_e\bec\bch\bho\bo shell option may be used
- to dynamically determine whether or not e\bec\bch\bho\bo interprets any op-
+ is given, interpretation of the following backslash-escaped
+ characters is enabled. The -\b-E\bE option disables the interpreta-
+ tion of these escape characters, even on systems where they are
+ interpreted by default. The x\bxp\bpg\bg_\b_e\bec\bch\bho\bo shell option may be used
+ to dynamically determine whether or not e\bec\bch\bho\bo interprets any op-
tions and expands these escape characters by default. e\bec\bch\bho\bo does
not interpret -\b--\b- to mean the end of options. e\bec\bch\bho\bo interprets
the following escape sequences:
e\ben\bna\bab\bbl\ble\be [-\b-a\ba] [-\b-d\bdn\bnp\bps\bs] [-\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be] [_\bn_\ba_\bm_\be ...]
Enable and disable builtin shell commands. Disabling a builtin
allows a disk command which has the same name as a shell builtin
- to be executed without specifying a full pathname, even though
- the shell normally searches for builtins before disk commands.
- If -\b-n\bn is used, each _\bn_\ba_\bm_\be is disabled; otherwise, _\bn_\ba_\bm_\be_\bs are en-
- abled. For example, to use the t\bte\bes\bst\bt binary found via the P\bPA\bAT\bTH\bH
- instead of the shell builtin version, run ``enable -n test''.
- The -\b-f\bf option means to load the new builtin command _\bn_\ba_\bm_\be from
- shared object _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, on systems that support dynamic loading.
- B\bBa\bas\bsh\bh will use the value of the B\bBA\bAS\bSH\bH_\b_L\bLO\bOA\bAD\bDA\bAB\bBL\bLE\bES\bS_\b_P\bPA\bAT\bTH\bH variable as a
+ to be executed without specifying a full pathname, even though
+ the shell normally searches for builtins before disk commands.
+ If -\b-n\bn is used, each _\bn_\ba_\bm_\be is disabled; otherwise, _\bn_\ba_\bm_\be_\bs are en-
+ abled. For example, to use the t\bte\bes\bst\bt binary found via the P\bPA\bAT\bTH\bH
+ instead of the shell builtin version, run "enable -n test". The
+ -\b-f\bf option means to load the new builtin command _\bn_\ba_\bm_\be from shared
+ object _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, on systems that support dynamic loading. B\bBa\bas\bsh\bh
+ will use the value of the B\bBA\bAS\bSH\bH_\b_L\bLO\bOA\bAD\bDA\bAB\bBL\bLE\bES\bS_\b_P\bPA\bAT\bTH\bH variable as a
colon-separated list of directories in which to search for _\bf_\bi_\bl_\be_\b-
_\bn_\ba_\bm_\be, if _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not contain a slash. The default is sys-
tem-dependent, and may include "." to force a search of the cur-
printed. If -\b-a\ba is supplied, the list printed includes all
builtins, with an indication of whether or not each is enabled.
If -\b-s\bs is supplied, the output is restricted to the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl
- builtins. If no options are supplied and a _\bn_\ba_\bm_\be is not a shell
- builtin, e\ben\bna\bab\bbl\ble\be will attempt to load _\bn_\ba_\bm_\be from a shared object
- named _\bn_\ba_\bm_\be, as if the command were ``enable -f _\bn_\ba_\bm_\be _\bn_\ba_\bm_\be . The
- return value is 0 unless a _\bn_\ba_\bm_\be is not a shell builtin or there
+ builtins. If no options are supplied and a _\bn_\ba_\bm_\be is not a shell
+ builtin, e\ben\bna\bab\bbl\ble\be will attempt to load _\bn_\ba_\bm_\be from a shared object
+ named _\bn_\ba_\bm_\be, as if the command were "enable -f _\bn_\ba_\bm_\be _\bn_\ba_\bm_\be". The
+ return value is 0 unless a _\bn_\ba_\bm_\be is not a shell builtin or there
is an error loading a new builtin from a shared object.
e\bev\bva\bal\bl [_\ba_\br_\bg ...]
- The _\ba_\br_\bgs are read and concatenated together into a single com-
- mand. This command is then read and executed by the shell, and
- its exit status is returned as the value of e\bev\bva\bal\bl. If there are
+ The _\ba_\br_\bgs are read and concatenated together into a single com-
+ mand. This command is then read and executed by the shell, and
+ its exit status is returned as the value of e\bev\bva\bal\bl. If there are
no _\ba_\br_\bg_\bs, or only null arguments, e\bev\bva\bal\bl returns 0.
e\bex\bxe\bec\bc [-\b-c\bcl\bl] [-\b-a\ba _\bn_\ba_\bm_\be] [_\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]]
- If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is specified, it replaces the shell. No new process
- is created. The _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs become the arguments to _\bc_\bo_\bm_\bm_\ba_\bn_\bd. If
+ If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is specified, it replaces the shell. No new process
+ is created. The _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs become the arguments to _\bc_\bo_\bm_\bm_\ba_\bn_\bd. If
the -\b-l\bl option is supplied, the shell places a dash at the begin-
ning of the zeroth argument passed to _\bc_\bo_\bm_\bm_\ba_\bn_\bd. This is what _\bl_\bo_\b-
- _\bg_\bi_\bn(1) does. The -\b-c\bc option causes _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed with
- an empty environment. If -\b-a\ba is supplied, the shell passes _\bn_\ba_\bm_\be
+ _\bg_\bi_\bn(1) does. The -\b-c\bc option causes _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed with
+ an empty environment. If -\b-a\ba is supplied, the shell passes _\bn_\ba_\bm_\be
as the zeroth argument to the executed command. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
not be executed for some reason, a non-interactive shell exits,
unless the e\bex\bxe\bec\bcf\bfa\bai\bil\bl shell option is enabled. In that case, it
e\bex\bxp\bpo\bor\brt\bt [-\b-f\bfn\bn] [_\bn_\ba_\bm_\be[=_\bw_\bo_\br_\bd]] ...
e\bex\bxp\bpo\bor\brt\bt -\b-p\bp
- The supplied _\bn_\ba_\bm_\be_\bs are marked for automatic export to the envi-
- ronment of subsequently executed commands. If the -\b-f\bf option is
- given, the _\bn_\ba_\bm_\be_\bs refer to functions. If no _\bn_\ba_\bm_\be_\bs are given, or
- if the -\b-p\bp option is supplied, a list of names of all exported
- variables is printed. The -\b-n\bn option causes the export property
+ The supplied _\bn_\ba_\bm_\be_\bs are marked for automatic export to the envi-
+ ronment of subsequently executed commands. If the -\b-f\bf option is
+ given, the _\bn_\ba_\bm_\be_\bs refer to functions. If no _\bn_\ba_\bm_\be_\bs are given, or
+ if the -\b-p\bp option is supplied, a list of names of all exported
+ variables is printed. The -\b-n\bn option causes the export property
to be removed from each _\bn_\ba_\bm_\be. If a variable name is followed by
=_\bw_\bo_\br_\bd, the value of the variable is set to _\bw_\bo_\br_\bd. e\bex\bxp\bpo\bor\brt\bt returns
an exit status of 0 unless an invalid option is encountered, one
_\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt of 0 is equivalent to -1 and -0 is equivalent to
the current command (usually the f\bfc\bc command); otherwise 0 is
equivalent to -1 and -0 is invalid. If _\bl_\ba_\bs_\bt is not specified,
- it is set to the current command for listing (so that ``fc -l
- -10'' prints the last 10 commands) and to _\bf_\bi_\br_\bs_\bt otherwise. If
+ it is set to the current command for listing (so that "fc -l
+ -10" prints the last 10 commands) and to _\bf_\bi_\br_\bs_\bt otherwise. If
_\bf_\bi_\br_\bs_\bt is not specified, it is set to the previous command for
editing and -16 for listing.
In the second form, _\bc_\bo_\bm_\bm_\ba_\bn_\bd is re-executed after each instance
of _\bp_\ba_\bt is replaced by _\br_\be_\bp. _\bC_\bo_\bm_\bm_\ba_\bn_\bd is interpreted the same as
- _\bf_\bi_\br_\bs_\bt above. A useful alias to use with this is ``r="fc -s"'',
- so that typing ``r cc'' runs the last command beginning with
- ``cc'' and typing ``r'' re-executes the last command.
+ _\bf_\bi_\br_\bs_\bt above. A useful alias to use with this is "r="fc -s"", so
+ that typing "r cc" runs the last command beginning with "cc" and
+ typing "r" re-executes the last command.
If the first form is used, the return value is 0 unless an in-
valid option is encountered or _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt specify history
f\bfg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc]
Resume _\bj_\bo_\bb_\bs_\bp_\be_\bc in the foreground, and make it the current job.
If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb
- is used. The return value is that of the command placed into
- the foreground, or failure if run when job control is disabled
+ is used. The return value is that of the command placed into
+ the foreground, or failure if run when job control is disabled
or, when run with job control enabled, if _\bj_\bo_\bb_\bs_\bp_\be_\bc does not spec-
ify a valid job or _\bj_\bo_\bb_\bs_\bp_\be_\bc specifies a job that was started
without job control.
- g\bge\bet\bto\bop\bpt\bts\bs _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg _\bn_\ba_\bm_\be [_\ba_\br_\bg _\b._\b._\b.]
+ g\bge\bet\bto\bop\bpt\bts\bs _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg _\bn_\ba_\bm_\be [_\ba_\br_\bg ...]
g\bge\bet\bto\bop\bpt\bts\bs is used by shell procedures to parse positional parame-
ters. _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg contains the option characters to be recog-
nized; if a character is followed by a colon, the option is ex-
pected to have an argument, which should be separated from it by
- white space. The colon and question mark characters may not be
- used as option characters. Each time it is invoked, g\bge\bet\bto\bop\bpt\bts\bs
- places the next option in the shell variable _\bn_\ba_\bm_\be, initializing
+ white space. The colon and question mark characters may not be
+ used as option characters. Each time it is invoked, g\bge\bet\bto\bop\bpt\bts\bs
+ places the next option in the shell variable _\bn_\ba_\bm_\be, initializing
_\bn_\ba_\bm_\be if it does not exist, and the index of the next argument to
be processed into the variable O\bOP\bPT\bTI\bIN\bND\bD. O\bOP\bPT\bTI\bIN\bND\bD is initialized to
1 each time the shell or a shell script is invoked. When an op-
variable O\bOP\bPT\bTE\bER\bRR\bR is set to 0, no error messages will be dis-
played, even if the first character of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is not a colon.
- If an invalid option is seen, g\bge\bet\bto\bop\bpt\bts\bs places ? into _\bn_\ba_\bm_\be and, if
- not silent, prints an error message and unsets O\bOP\bPT\bTA\bAR\bRG\bG. If
- g\bge\bet\bto\bop\bpt\bts\bs is silent, the option character found is placed in O\bOP\bP-\b-
- T\bTA\bAR\bRG\bG and no diagnostic message is printed.
+ If g\bge\bet\bto\bop\bpt\bts\bs detects an invalid option, it places ? into _\bn_\ba_\bm_\be and,
+ if not silent, prints an error message and unsets O\bOP\bPT\bTA\bAR\bRG\bG. If
+ g\bge\bet\bto\bop\bpt\bts\bs is silent, it assigns the option character found to O\bOP\bP-\b-
+ T\bTA\bAR\bRG\bG and does not print a diagnostic message.
- If a required argument is not found, and g\bge\bet\bto\bop\bpt\bts\bs is not silent,
- a question mark (?\b?) is placed in _\bn_\ba_\bm_\be, O\bOP\bPT\bTA\bAR\bRG\bG is unset, and a
- diagnostic message is printed. If g\bge\bet\bto\bop\bpt\bts\bs is silent, then a
- colon (:\b:) is placed in _\bn_\ba_\bm_\be and O\bOP\bPT\bTA\bAR\bRG\bG is set to the option
+ If a required argument is not found, and g\bge\bet\bto\bop\bpt\bts\bs is not silent,
+ it sets the value of _\bn_\ba_\bm_\be to a question mark (?\b?), unsets O\bOP\bPT\bTA\bAR\bRG\bG,
+ and prints a diagnostic message. If g\bge\bet\bto\bop\bpt\bts\bs is silent, it sets
+ the value of _\bn_\ba_\bm_\be to a colon (:\b:) and sets O\bOP\bPT\bTA\bAR\bRG\bG to the option
character found.
g\bge\bet\bto\bop\bpt\bts\bs returns true if an option, specified or unspecified, is
Each time h\bha\bas\bsh\bh is invoked, the full pathname of the command _\bn_\ba_\bm_\be
is determined by searching the directories in $\b$P\bPA\bAT\bTH\bH and remem-
bered. Any previously-remembered pathname is discarded. If the
- -\b-p\bp option is supplied, h\bha\bas\bsh\bh uses _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be as the full filename
- of the command. The -\b-r\br option causes the shell to forget all
- remembered locations. Assigning to the P\bPA\bAT\bTH\bH variable also
- clears all hashed filenames. The -\b-d\bd option causes the shell to
- forget the remembered location of each _\bn_\ba_\bm_\be. If the -\b-t\bt option
+ -\b-p\bp option is supplied, h\bha\bas\bsh\bh uses _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be as the full filename
+ of the command. The -\b-r\br option causes the shell to forget all
+ remembered locations. Assigning to the P\bPA\bAT\bTH\bH variable also
+ clears all hashed filenames. The -\b-d\bd option causes the shell to
+ forget the remembered location of each _\bn_\ba_\bm_\be. If the -\b-t\bt option
is supplied, the full pathname to which each _\bn_\ba_\bm_\be corresponds is
printed. If multiple _\bn_\ba_\bm_\be arguments are supplied with -\b-t\bt, the
_\bn_\ba_\bm_\be is printed before the hashed full pathname. The -\b-l\bl option
and -\b-p\bp options (the options that act on the _\bn_\ba_\bm_\be arguments) are
mutually exclusive. Only one will be active. If more than one
is supplied, -\b-t\bt has higher priority than -\b-p\bp, and both are higher
- priority than -\b-d\bd. The return status is true unless a _\bn_\ba_\bm_\be is
+ priority than -\b-d\bd. The return status is true unless a _\bn_\ba_\bm_\be is
not found or an invalid option is supplied.
h\bhe\bel\blp\bp [-\b-d\bdm\bms\bs] [_\bp_\ba_\bt_\bt_\be_\br_\bn]
- Display helpful information about builtin commands. If _\bp_\ba_\bt_\bt_\be_\br_\bn
- is specified, h\bhe\bel\blp\bp gives detailed help on all commands matching
- _\bp_\ba_\bt_\bt_\be_\br_\bn; otherwise help for all the builtins and shell control
+ Display helpful information about builtin commands. If _\bp_\ba_\bt_\bt_\be_\br_\bn
+ is specified, h\bhe\bel\blp\bp gives detailed help on all commands matching
+ _\bp_\ba_\bt_\bt_\be_\br_\bn; otherwise help for all the builtins and shell control
structures is printed.
-\b-d\bd Display a short description of each _\bp_\ba_\bt_\bt_\be_\br_\bn
-\b-m\bm Display the description of each _\bp_\ba_\bt_\bt_\be_\br_\bn in a manpage-like
h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bs_\bt_\ba_\br_\bt-_\be_\bn_\bd
h\bhi\bis\bst\bto\bor\bry\by -\b-a\ban\bnr\brw\bw [_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be]
- h\bhi\bis\bst\bto\bor\bry\by -\b-p\bp _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
- h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
+ h\bhi\bis\bst\bto\bor\bry\by -\b-p\bp _\ba_\br_\bg [_\ba_\br_\bg ...]
+ h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg ...]
With no options, display the command history list with line num-
bers. Lines listed with a *\b* have been modified. An argument of
_\bn lists only the last _\bn lines. If the shell variable H\bHI\bIS\bST\bTT\bTI\bIM\bME\bE-\b-
Delete the range of history entries between positions
_\bs_\bt_\ba_\br_\bt and _\be_\bn_\bd, inclusive. Positive and negative values
for _\bs_\bt_\ba_\br_\bt and _\be_\bn_\bd are interpreted as described above.
- -\b-a\ba Append the ``new'' history lines to the history file.
+ -\b-a\ba Append the "new" history lines to the history file.
These are history lines entered since the beginning of
the current b\bba\bas\bsh\bh session, but not already appended to the
history file.
- -\b-n\bn Read the history lines not already read from the history
- file into the current history list. These are lines ap-
- pended to the history file since the beginning of the
+ -\b-n\bn Read the history lines not already read from the history
+ file into the current history list. These are lines ap-
+ pended to the history file since the beginning of the
current b\bba\bas\bsh\bh session.
- -\b-r\br Read the contents of the history file and append them to
+ -\b-r\br Read the contents of the history file and append them to
the current history list.
-\b-w\bw Write the current history list to the history file, over-
writing the history file's contents.
The first form lists the active jobs. The options have the fol-
lowing meanings:
-\b-l\bl List process IDs in addition to the normal information.
- -\b-n\bn Display information only about jobs that have changed
+ -\b-n\bn Display information only about jobs that have changed
status since the user was last notified of their status.
- -\b-p\bp List only the process ID of the job's process group
+ -\b-p\bp List only the process ID of the job's process group
leader.
-\b-r\br Display only running jobs.
-\b-s\bs Display only stopped jobs.
- If _\bj_\bo_\bb_\bs_\bp_\be_\bc is given, output is restricted to information about
- that job. The return status is 0 unless an invalid option is
+ If _\bj_\bo_\bb_\bs_\bp_\be_\bc is given, output is restricted to information about
+ that job. The return status is 0 unless an invalid option is
encountered or an invalid _\bj_\bo_\bb_\bs_\bp_\be_\bc is supplied.
If the -\b-x\bx option is supplied, j\bjo\bob\bbs\bs replaces any _\bj_\bo_\bb_\bs_\bp_\be_\bc found in
k\bki\bil\bll\bl [-\b-s\bs _\bs_\bi_\bg_\bs_\bp_\be_\bc | -\b-n\bn _\bs_\bi_\bg_\bn_\bu_\bm | -\b-_\bs_\bi_\bg_\bs_\bp_\be_\bc] [_\bp_\bi_\bd | _\bj_\bo_\bb_\bs_\bp_\be_\bc] ...
k\bki\bil\bll\bl -\b-l\bl|-\b-L\bL [_\bs_\bi_\bg_\bs_\bp_\be_\bc | _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs]
- Send the signal named by _\bs_\bi_\bg_\bs_\bp_\be_\bc or _\bs_\bi_\bg_\bn_\bu_\bm to the processes
- named by _\bp_\bi_\bd or _\bj_\bo_\bb_\bs_\bp_\be_\bc. _\bs_\bi_\bg_\bs_\bp_\be_\bc is either a case-insensitive
- signal name such as S\bSI\bIG\bGK\bKI\bIL\bLL\bL (with or without the S\bSI\bIG\bG prefix) or
- a signal number; _\bs_\bi_\bg_\bn_\bu_\bm is a signal number. If _\bs_\bi_\bg_\bs_\bp_\be_\bc is not
- present, then S\bSI\bIG\bGT\bTE\bER\bRM\bM is assumed. An argument of -\b-l\bl lists the
- signal names. If any arguments are supplied when -\b-l\bl is given,
- the names of the signals corresponding to the arguments are
+ Send the signal named by _\bs_\bi_\bg_\bs_\bp_\be_\bc or _\bs_\bi_\bg_\bn_\bu_\bm to the processes
+ named by _\bp_\bi_\bd or _\bj_\bo_\bb_\bs_\bp_\be_\bc. _\bs_\bi_\bg_\bs_\bp_\be_\bc is either a case-insensitive
+ signal name such as S\bSI\bIG\bGK\bKI\bIL\bLL\bL (with or without the S\bSI\bIG\bG prefix) or
+ a signal number; _\bs_\bi_\bg_\bn_\bu_\bm is a signal number. If _\bs_\bi_\bg_\bs_\bp_\be_\bc is not
+ present, then S\bSI\bIG\bGT\bTE\bER\bRM\bM is assumed. An argument of -\b-l\bl lists the
+ signal names. If any arguments are supplied when -\b-l\bl is given,
+ the names of the signals corresponding to the arguments are
listed, and the return status is 0. The _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs argument to
-\b-l\bl is a number specifying either a signal number or the exit
status of a process terminated by a signal. The -\b-L\bL option is
For each argument, a local variable named _\bn_\ba_\bm_\be is created, and
assigned _\bv_\ba_\bl_\bu_\be. The _\bo_\bp_\bt_\bi_\bo_\bn can be any of the options accepted
by d\bde\bec\bcl\bla\bar\bre\be. When l\blo\boc\bca\bal\bl is used within a function, it causes the
- variable _\bn_\ba_\bm_\be to have a visible scope restricted to that func-
- tion and its children. If _\bn_\ba_\bm_\be is -, the set of shell options
- is made local to the function in which l\blo\boc\bca\bal\bl is invoked: shell
- options changed using the s\bse\bet\bt builtin inside the function after
+ variable _\bn_\ba_\bm_\be to have a visible scope restricted to that func-
+ tion and its children. If _\bn_\ba_\bm_\be is -, the set of shell options
+ is made local to the function in which l\blo\boc\bca\bal\bl is invoked: shell
+ options changed using the s\bse\bet\bt builtin inside the function after
the call to l\blo\boc\bca\bal\bl are restored to their original values when the
function returns. The restore is effected as if a series of s\bse\bet\bt
- commands were executed to restore the values that were in place
- before the function. With no operands, l\blo\boc\bca\bal\bl writes a list of
- local variables to the standard output. It is an error to use
+ commands were executed to restore the values that were in place
+ before the function. With no operands, l\blo\boc\bca\bal\bl writes a list of
+ local variables to the standard output. It is an error to use
l\blo\boc\bca\bal\bl when not within a function. The return status is 0 unless
l\blo\boc\bca\bal\bl is used outside a function, an invalid _\bn_\ba_\bm_\be is supplied,
or _\bn_\ba_\bm_\be is a readonly variable.
l\blo\bog\bgo\bou\but\bt Exit a login shell.
- m\bma\bap\bpf\bfi\bil\ble\be [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC
+ m\bma\bap\bpf\bfi\bil\ble\be [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC
_\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk] [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
r\bre\bea\bad\bda\bar\brr\bra\bay\by [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC
_\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk] [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
input line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
string, m\bma\bap\bpf\bfi\bil\ble\be will terminate a line when it reads a NUL
character.
- -\b-n\bn Copy at most _\bc_\bo_\bu_\bn_\bt lines. If _\bc_\bo_\bu_\bn_\bt is 0, all lines are
+ -\b-n\bn Copy at most _\bc_\bo_\bu_\bn_\bt lines. If _\bc_\bo_\bu_\bn_\bt is 0, all lines are
copied.
- -\b-O\bO Begin assigning to _\ba_\br_\br_\ba_\by at index _\bo_\br_\bi_\bg_\bi_\bn. The default
+ -\b-O\bO Begin assigning to _\ba_\br_\br_\ba_\by at index _\bo_\br_\bi_\bg_\bi_\bn. The default
index is 0.
-\b-s\bs Discard the first _\bc_\bo_\bu_\bn_\bt lines read.
- -\b-t\bt Remove a trailing _\bd_\be_\bl_\bi_\bm (default newline) from each line
+ -\b-t\bt Remove a trailing _\bd_\be_\bl_\bi_\bm (default newline) from each line
read.
- -\b-u\bu Read lines from file descriptor _\bf_\bd instead of the stan-
+ -\b-u\bu Read lines from file descriptor _\bf_\bd instead of the stan-
dard input.
- -\b-C\bC Evaluate _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk each time _\bq_\bu_\ba_\bn_\bt_\bu_\bm lines are read. The
+ -\b-C\bC Evaluate _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk each time _\bq_\bu_\ba_\bn_\bt_\bu_\bm lines are read. The
-\b-c\bc option specifies _\bq_\bu_\ba_\bn_\bt_\bu_\bm.
- -\b-c\bc Specify the number of lines read between each call to
+ -\b-c\bc Specify the number of lines read between each call to
_\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk.
- If -\b-C\bC is specified without -\b-c\bc, the default quantum is 5000.
+ If -\b-C\bC is specified without -\b-c\bc, the default quantum is 5000.
When _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk is evaluated, it is supplied the index of the next
array element to be assigned and the line to be assigned to that
- element as additional arguments. _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk is evaluated after
+ element as additional arguments. _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk is evaluated after
the line is read but before the array element is assigned.
- If not supplied with an explicit origin, m\bma\bap\bpf\bfi\bil\ble\be will clear _\ba_\br_\b-
+ If not supplied with an explicit origin, m\bma\bap\bpf\bfi\bil\ble\be will clear _\ba_\br_\b-
_\br_\ba_\by before assigning to it.
- m\bma\bap\bpf\bfi\bil\ble\be returns successfully unless an invalid option or option
- argument is supplied, _\ba_\br_\br_\ba_\by is invalid or unassignable, or if
+ m\bma\bap\bpf\bfi\bil\ble\be returns successfully unless an invalid option or option
+ argument is supplied, _\ba_\br_\br_\ba_\by is invalid or unassignable, or if
_\ba_\br_\br_\ba_\by is not an indexed array.
p\bpo\bop\bpd\bd [-n\bn] [+_\bn] [-_\bn]
With no arguments, p\bpo\bop\bpd\bd removes the top directory from the
stack, and changes to the new top directory. Arguments, if sup-
plied, have the following meanings:
- -\b-n\bn Suppresses the normal change of directory when removing
+ -\b-n\bn Suppresses the normal change of directory when removing
directories from the stack, so that only the stack is ma-
nipulated.
+\b+_\bn Removes the _\bnth entry counting from the left of the list
shown by d\bdi\bir\brs\bs, starting with zero, from the stack. For
- example: ``popd +0'' removes the first directory, ``popd
- +1'' the second.
+ example: "popd +0" removes the first directory, "popd +1"
+ the second.
-\b-_\bn Removes the _\bnth entry counting from the right of the list
- shown by d\bdi\bir\brs\bs, starting with zero. For example: ``popd
- -0'' removes the last directory, ``popd -1'' the next to
+ shown by d\bdi\bir\brs\bs, starting with zero. For example: "popd
+ -0" removes the last directory, "popd -1" the next to
last.
If the top element of the directory stack is modified, and the
to the directory at the top of the stack. If the c\bcd\bd fails, p\bpo\bop\bpd\bd
returns a non-zero value.
- Otherwise, p\bpo\bop\bpd\bd returns false if an invalid option is encoun-
+ Otherwise, p\bpo\bop\bpd\bd returns false if an invalid option is encoun-
tered, the directory stack is empty, or a non-existent directory
stack entry is specified.
ifiers:
%\b%b\bb causes p\bpr\bri\bin\bnt\btf\bf to expand backslash escape sequences in the
corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in the same way as e\bec\bch\bho\bo -\b-e\be.
- %\b%q\bq causes p\bpr\bri\bin\bnt\btf\bf to output the corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in a
- format that can be reused as shell input. %\b%q\bq and %\b%Q\bQ use
- the $\b$'\b''\b' quoting style if any characters in the argument
- string require it, and backslash quoting otherwise. If
- the format string uses the _\bp_\br_\bi_\bn_\bt_\bf alternate form, these
+ %\b%q\bq causes p\bpr\bri\bin\bnt\btf\bf to output the corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in a
+ format that can be reused as shell input. %\b%q\bq and %\b%Q\bQ use
+ the $\b$'\b''\b' quoting style if any characters in the argument
+ string require it, and backslash quoting otherwise. If
+ the format string uses the _\bp_\br_\bi_\bn_\bt_\bf alternate form, these
two formats quote the argument string using single
quotes.
- %\b%Q\bQ like %\b%q\bq, but applies any supplied precision to the _\ba_\br_\bg_\bu_\b-
+ %\b%Q\bQ like %\b%q\bq, but applies any supplied precision to the _\ba_\br_\bg_\bu_\b-
_\bm_\be_\bn_\bt before quoting it.
%\b%(\b(_\bd_\ba_\bt_\be_\bf_\bm_\bt)\b)T\bT
- causes p\bpr\bri\bin\bnt\btf\bf to output the date-time string resulting
- from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
+ causes p\bpr\bri\bin\bnt\btf\bf to output the date-time string resulting
+ from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
The corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt is an integer representing the
number of seconds since the epoch. Two special argument
values may be used: -1 represents the current time, and
-2 represents the time the shell was invoked. If no ar-
gument is specified, conversion behaves as if -1 had been
- given. This is an exception to the usual p\bpr\bri\bin\bnt\btf\bf behav-
+ given. This is an exception to the usual p\bpr\bri\bin\bnt\btf\bf behav-
ior.
The %b, %q, and %T format specifiers all use the field width and
precision arguments from the format specification and write that
- many bytes from (or use that wide a field for) the expanded ar-
- gument, which usually contains more characters than the origi-
+ many bytes from (or use that wide a field for) the expanded ar-
+ gument, which usually contains more characters than the origi-
nal.
The %n format specifier accepts a corresponding argument that is
Arguments to non-string format specifiers are treated as C con-
stants, except that a leading plus or minus sign is allowed, and
- if the leading character is a single or double quote, the value
+ if the leading character is a single or double quote, the value
is the ASCII value of the following character.
- The _\bf_\bo_\br_\bm_\ba_\bt is reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
+ The _\bf_\bo_\br_\bm_\ba_\bt is reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
_\bm_\be_\bn_\bt_\bs. If the _\bf_\bo_\br_\bm_\ba_\bt requires more _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs than are supplied,
the extra format specifications behave as if a zero value or
null string, as appropriate, had been supplied. The return
_\bd_\bi_\br Adds _\bd_\bi_\br to the directory stack at the top
After the stack has been modified, if the -\b-n\bn option was not sup-
- plied, p\bpu\bus\bsh\bhd\bd uses the c\bcd\bd builtin to change to the directory at
+ plied, p\bpu\bus\bsh\bhd\bd uses the c\bcd\bd builtin to change to the directory at
the top of the stack. If the c\bcd\bd fails, p\bpu\bus\bsh\bhd\bd returns a non-zero
value.
occurs while reading the name of the current directory or an in-
valid option is supplied.
- r\bre\bea\bad\bd [-\b-E\bEe\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-i\bi _\bt_\be_\bx_\bt] [-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs] [-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs]
+ r\bre\bea\bad\bd [-\b-E\bEe\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-i\bi _\bt_\be_\bx_\bt] [-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs] [-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs]
[-\b-p\bp _\bp_\br_\bo_\bm_\bp_\bt] [-\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt] [-\b-u\bu _\bf_\bd] [_\bn_\ba_\bm_\be ...]
One line is read from the standard input, or from the file de-
scriptor _\bf_\bd supplied as an argument to the -\b-u\bu option, split into
- words as described above under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the first
- word is assigned to the first _\bn_\ba_\bm_\be, the second word to the sec-
- ond _\bn_\ba_\bm_\be, and so on. If there are more words than names, the
+ words as described above under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the first
+ word is assigned to the first _\bn_\ba_\bm_\be, the second word to the sec-
+ ond _\bn_\ba_\bm_\be, and so on. If there are more words than names, the
remaining words and their intervening delimiters are assigned to
the last _\bn_\ba_\bm_\be. If there are fewer words read from the input
stream than names, the remaining names are assigned empty val-
words using the same rules the shell uses for expansion (de-
scribed above under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg). The backslash character
(\\b\) may be used to remove any special meaning for the next char-
- acter read and for line continuation. Options, if supplied,
+ acter read and for line continuation. Options, if supplied,
have the following meanings:
-\b-a\ba _\ba_\bn_\ba_\bm_\be
The words are assigned to sequential indices of the array
variable _\ba_\bn_\ba_\bm_\be, starting at 0. _\ba_\bn_\ba_\bm_\be is unset before any
- new values are assigned. Other _\bn_\ba_\bm_\be arguments are ig-
+ new values are assigned. Other _\bn_\ba_\bm_\be arguments are ig-
nored.
-\b-d\bd _\bd_\be_\bl_\bi_\bm
The first character of _\bd_\be_\bl_\bi_\bm is used to terminate the in-
bash's default completion, including programmable comple-
tion.
-\b-i\bi _\bt_\be_\bx_\bt
- If r\bre\bea\bad\bdl\bli\bin\bne\be is being used to read the line, _\bt_\be_\bx_\bt is
+ If r\bre\bea\bad\bdl\bli\bin\bne\be is being used to read the line, _\bt_\be_\bx_\bt is
placed into the editing buffer before editing begins.
-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs
- r\bre\bea\bad\bd returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
+ r\bre\bea\bad\bd returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
waiting for a complete line of input, but honors a delim-
iter if fewer than _\bn_\bc_\bh_\ba_\br_\bs characters are read before the
delimiter.
-\b-s\bs Silent mode. If input is coming from a terminal, charac-
ters are not echoed.
-\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt
- Cause r\bre\bea\bad\bd to time out and return failure if a complete
- line of input (or a specified number of characters) is
- not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a deci-
- mal number with a fractional portion following the deci-
- mal point. This option is only effective if r\bre\bea\bad\bd is
- reading input from a terminal, pipe, or other special
- file; it has no effect when reading from regular files.
+ Cause r\bre\bea\bad\bd to time out and return failure if a complete
+ line of input (or a specified number of characters) is
+ not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a deci-
+ mal number with a fractional portion following the deci-
+ mal point. This option is only effective if r\bre\bea\bad\bd is
+ reading input from a terminal, pipe, or other special
+ file; it has no effect when reading from regular files.
If r\bre\bea\bad\bd times out, r\bre\bea\bad\bd saves any partial input read into
the specified variable _\bn_\ba_\bm_\be. If _\bt_\bi_\bm_\be_\bo_\bu_\bt is 0, r\bre\bea\bad\bd re-
turns immediately, without trying to read any data. The
timeout is exceeded.
-\b-u\bu _\bf_\bd Read input from file descriptor _\bf_\bd.
- If no _\bn_\ba_\bm_\be_\bs are supplied, the line read, without the ending de-
- limiter but otherwise unmodified, is assigned to the variable
- R\bRE\bEP\bPL\bLY\bY. The exit status is zero, unless end-of-file is encoun-
- tered, r\bre\bea\bad\bd times out (in which case the status is greater than
- 128), a variable assignment error (such as assigning to a read-
+ Other than the case where _\bd_\be_\bl_\bi_\bm is the empty string, r\bre\bea\bad\bd ig-
+ nores any NUL characters in the input.
+
+ If no _\bn_\ba_\bm_\be_\bs are supplied, the line read, without the ending de-
+ limiter but otherwise unmodified, is assigned to the variable
+ R\bRE\bEP\bPL\bLY\bY. The exit status is zero, unless end-of-file is encoun-
+ tered, r\bre\bea\bad\bd times out (in which case the status is greater than
+ 128), a variable assignment error (such as assigning to a read-
only variable) occurs, or an invalid file descriptor is supplied
as the argument to -\b-u\bu.
marked. The -\b-a\ba option restricts the variables to indexed ar-
rays; the -\b-A\bA option restricts the variables to associative ar-
rays. If both options are supplied, -\b-A\bA takes precedence. If no
- _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
+ _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
list of all readonly names is printed. The other options may be
used to restrict the output to a subset of the set of readonly
names. The -\b-p\bp option causes output to be displayed in a format
a _\bn_\ba_\bm_\be that is not a function.
r\bre\bet\btu\bur\brn\bn [_\bn]
- Causes a function to stop executing and return the value speci-
- fied by _\bn to its caller. If _\bn is omitted, the return status is
- that of the last command executed in the function body. If r\bre\be-\b-
+ Causes a function to stop executing and return the value speci-
+ fied by _\bn to its caller. If _\bn is omitted, the return status is
+ that of the last command executed in the function body. If r\bre\be-\b-
t\btu\bur\brn\bn is executed by a trap handler, the last command used to de-
termine the status is the last command executed before the trap
handler. If r\bre\bet\btu\bur\brn\bn is executed during a D\bDE\bEB\bBU\bUG\bG trap, the last
that script and return either _\bn or the exit status of the last
command executed within the script as the exit status of the
script. If _\bn is supplied, the return value is its least signif-
- icant 8 bits. The return status is non-zero if r\bre\bet\btu\bur\brn\bn is sup-
- plied a non-numeric argument, or is used outside a function and
- not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be. Any command
+ icant 8 bits. The return status is non-zero if r\bre\bet\btu\bur\brn\bn is sup-
+ plied a non-numeric argument, or is used outside a function and
+ not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be. Any command
associated with the R\bRE\bET\bTU\bUR\bRN\bN trap is executed before execution re-
sumes after the function or script.
s\bse\bet\bt +\b+o\bo Without options, display the name and value of each shell vari-
able in a format that can be reused as input for setting or re-
setting the currently-set variables. Read-only variables cannot
- be reset. In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed. The
- output is sorted according to the current locale. When options
- are specified, they set or unset shell attributes. Any argu-
- ments remaining after option processing are treated as values
+ be reset. In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed. The
+ output is sorted according to the current locale. When options
+ are specified, they set or unset shell attributes. Any argu-
+ ments remaining after option processing are treated as values
for the positional parameters and are assigned, in order, to $\b$1\b1,
- $\b$2\b2, .\b..\b..\b. $\b$_\bn. Options, if specified, have the following mean-
+ $\b$2\b2, ..., $\b$_\bn. Options, if specified, have the following mean-
ings:
-\b-a\ba Each variable or function that is created or modified is
- given the export attribute and marked for export to the
+ given the export attribute and marked for export to the
environment of subsequent commands.
- -\b-b\bb Report the status of terminated background jobs immedi-
+ -\b-b\bb Report the status of terminated background jobs immedi-
ately, rather than before the next primary prompt. This
is effective only when job control is enabled.
-\b-e\be Exit immediately if a _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be (which may consist of a
single _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd), a _\bl_\bi_\bs_\bt, or a _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd _\bc_\bo_\bm_\bm_\ba_\bn_\bd
(see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR above), exits with a non-zero status.
- The shell does not exit if the command that fails is
- part of the command list immediately following a w\bwh\bhi\bil\ble\be
- or u\bun\bnt\bti\bil\bl keyword, part of the test following the i\bif\bf or
- e\bel\bli\bif\bf reserved words, part of any command executed in a
- &\b&&\b& or |\b||\b| list except the command following the final &\b&&\b&
+ The shell does not exit if the command that fails is
+ part of the command list immediately following a w\bwh\bhi\bil\ble\be
+ or u\bun\bnt\bti\bil\bl keyword, part of the test following the i\bif\bf or
+ e\bel\bli\bif\bf reserved words, part of any command executed in a
+ &\b&&\b& or |\b||\b| list except the command following the final &\b&&\b&
or |\b||\b|, any command in a pipeline but the last, or if the
command's return value is being inverted with !\b!. If a
compound command other than a subshell returns a non-
ignored, the shell does not exit. A trap on E\bER\bRR\bR, if
set, is executed before the shell exits. This option
applies to the shell environment and each subshell envi-
- ronment separately (see C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bNM\bME\bEN\bNT\bT
+ ronment separately (see C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bNM\bME\bEN\bNT\bT
above), and may cause subshells to exit before executing
all the commands in the subshell.
pletes, the shell prints a line containing its exit sta-
tus.
-\b-n\bn Read commands but do not execute them. This may be used
- to check a shell script for syntax errors. This is ig-
+ to check a shell script for syntax errors. This is ig-
nored by interactive shells.
-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
The _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be can be one of the following:
Same as -\b-a\ba.
b\bbr\bra\bac\bce\bee\bex\bxp\bpa\ban\bnd\bd
Same as -\b-B\bB.
- e\bem\bma\bac\bcs\bs Use an emacs-style command line editing inter-
+ e\bem\bma\bac\bcs\bs Use an emacs-style command line editing inter-
face. This is enabled by default when the shell
is interactive, unless the shell is started with
- the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option. This also affects the
+ the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option. This also affects the
editing interface used for r\bre\bea\bad\bd -\b-e\be.
e\ber\brr\bre\bex\bxi\bit\bt Same as -\b-e\be.
e\ber\brr\brt\btr\bra\bac\bce\be
H\bHI\bIS\bST\bTO\bOR\bRY\bY. This option is on by default in inter-
active shells.
i\big\bgn\bno\bor\bre\bee\beo\bof\bf
- The effect is as if the shell command ``IG-
- NOREEOF=10'' had been executed (see S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bi-\b-
- a\bab\bbl\ble\bes\bs above).
+ The effect is as if the shell command
+ "IGNOREEOF=10" had been executed (see S\bSh\bhe\bel\bll\bl
+ V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs above).
k\bke\bey\byw\bwo\bor\brd\bd Same as -\b-k\bk.
m\bmo\bon\bni\bit\bto\bor\br Same as -\b-m\bm.
n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br
p\bph\bhy\bys\bsi\bic\bca\bal\bl
Same as -\b-P\bP.
p\bpi\bip\bpe\bef\bfa\bai\bil\bl
- If set, the return value of a pipeline is the
- value of the last (rightmost) command to exit
- with a non-zero status, or zero if all commands
- in the pipeline exit successfully. This option
+ If set, the return value of a pipeline is the
+ value of the last (rightmost) command to exit
+ with a non-zero status, or zero if all commands
+ in the pipeline exit successfully. This option
is disabled by default.
- p\bpo\bos\bsi\bix\bx Change the behavior of b\bba\bas\bsh\bh where the default
- operation differs from the POSIX standard to
- match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be). See S\bSE\bEE\bE A\bAL\bLS\bSO\bO
+ p\bpo\bos\bsi\bix\bx Change the behavior of b\bba\bas\bsh\bh where the default
+ operation differs from the POSIX standard to
+ match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be). See S\bSE\bEE\bE A\bAL\bLS\bSO\bO
below for a reference to a document that details
how posix mode affects bash's behavior.
p\bpr\bri\biv\bvi\bil\ble\beg\bge\bed\bd
This also affects the editing interface used for
r\bre\bea\bad\bd -\b-e\be.
x\bxt\btr\bra\bac\bce\be Same as -\b-x\bx.
- If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints the
- current shell option settings. If +\b+o\bo is supplied with
- no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints a series of s\bse\bet\bt commands to
- recreate the current option settings on the standard
+ If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints the
+ current shell option settings. If +\b+o\bo is supplied with
+ no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints a series of s\bse\bet\bt commands to
+ recreate the current option settings on the standard
output.
- -\b-p\bp Turn on _\bp_\br_\bi_\bv_\bi_\bl_\be_\bg_\be_\bd mode. In this mode, the $\b$E\bEN\bNV\bV and
- $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV files are not processed, shell functions are
- not inherited from the environment, and the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
- B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
- pear in the environment, are ignored. If the shell is
- started with the effective user (group) id not equal to
- the real user (group) id, and the -\b-p\bp option is not sup-
+ -\b-p\bp Turn on _\bp_\br_\bi_\bv_\bi_\bl_\be_\bg_\be_\bd mode. In this mode, the $\b$E\bEN\bNV\bV and
+ $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV files are not processed, shell functions are
+ not inherited from the environment, and the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
+ B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
+ pear in the environment, are ignored. If the shell is
+ started with the effective user (group) id not equal to
+ the real user (group) id, and the -\b-p\bp option is not sup-
plied, these actions are taken and the effective user id
is set to the real user id. If the -\b-p\bp option is sup-
plied at startup, the effective user id is not reset.
-\b-v\bv Print shell input lines as they are read.
-\b-x\bx After expanding each _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, f\bfo\bor\br command, c\bca\bas\bse\be
command, s\bse\bel\ble\bec\bct\bt command, or arithmetic f\bfo\bor\br command, dis-
- play the expanded value of P\bPS\bS4\b4, followed by the command
- and its expanded arguments or associated word list, to
+ play the expanded value of P\bPS\bS4\b4, followed by the command
+ and its expanded arguments or associated word list, to
standard error.
- -\b-B\bB The shell performs brace expansion (see B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
+ -\b-B\bB The shell performs brace expansion (see B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
above). This is on by default.
- -\b-C\bC If set, b\bba\bas\bsh\bh does not overwrite an existing file with
- the >\b>, >\b>&\b&, and <\b<>\b> redirection operators. This may be
+ -\b-C\bC If set, b\bba\bas\bsh\bh does not overwrite an existing file with
+ the >\b>, >\b>&\b&, and <\b<>\b> redirection operators. This may be
overridden when creating output files by using the redi-
rection operator >\b>|\b| instead of >\b>.
-\b-E\bE If set, any trap on E\bER\bRR\bR is inherited by shell functions,
- command substitutions, and commands executed in a sub-
- shell environment. The E\bER\bRR\bR trap is normally not inher-
+ command substitutions, and commands executed in a sub-
+ shell environment. The E\bER\bRR\bR trap is normally not inher-
ited in such cases.
-\b-H\bH Enable !\b! style history substitution. This option is on
by default when the shell is interactive.
executing commands such as c\bcd\bd that change the current
working directory. It uses the physical directory
structure instead. By default, b\bba\bas\bsh\bh follows the logical
- chain of directories when performing commands which
+ chain of directories when performing commands which
change the current directory.
- -\b-T\bT If set, any traps on D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN are inherited by
+ -\b-T\bT If set, any traps on D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN are inherited by
shell functions, command substitutions, and commands ex-
ecuted in a subshell environment. The D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN
traps are normally not inherited in such cases.
-\b--\b- If no arguments follow this option, then the positional
parameters are unset. Otherwise, the positional parame-
- ters are set to the _\ba_\br_\bgs, even if some of them begin
+ ters are set to the _\ba_\br_\bgs, even if some of them begin
with a -\b-.
- -\b- Signal the end of options, cause all remaining _\ba_\br_\bgs to
+ -\b- Signal the end of options, cause all remaining _\ba_\br_\bgs to
be assigned to the positional parameters. The -\b-x\bx and -\b-v\bv
options are turned off. If there are no _\ba_\br_\bgs, the posi-
tional parameters remain unchanged.
- The options are off by default unless otherwise noted. Using +
- rather than - causes these options to be turned off. The op-
+ The options are off by default unless otherwise noted. Using +
+ rather than - causes these options to be turned off. The op-
tions can also be specified as arguments to an invocation of the
shell. The current set of options may be found in $\b$-\b-. The re-
turn status is always true unless an invalid option is encoun-
Parameters represented by the numbers $\b$#\b# down to $\b$#\b#-_\bn+1 are un-
set. _\bn must be a non-negative number less than or equal to $\b$#\b#.
If _\bn is 0, no parameters are changed. If _\bn is not given, it is
- assumed to be 1. If _\bn is greater than $\b$#\b#, the positional param-
- eters are not changed. The return status is greater than zero
+ assumed to be 1. If _\bn is greater than $\b$#\b#, the positional para-
+ meters are not changed. The return status is greater than zero
if _\bn is greater than $\b$#\b# or less than zero; otherwise 0.
s\bsh\bho\bop\bpt\bt [-\b-p\bpq\bqs\bsu\bu] [-\b-o\bo] [_\bo_\bp_\bt_\bn_\ba_\bm_\be ...]
builtin command. With no options, or with the -\b-p\bp option, a list
of all settable options is displayed, with an indication of
whether or not each is set; if _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are supplied, the output
- is restricted to those options. The -\b-p\bp option causes output to
- be displayed in a form that may be reused as input. Other op-
+ is restricted to those options. The -\b-p\bp option causes output to
+ be displayed in a form that may be reused as input. Other op-
tions have the following meanings:
-\b-s\bs Enable (set) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
-\b-u\bu Disable (unset) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
- -\b-q\bq Suppresses normal output (quiet mode); the return status
+ -\b-q\bq Suppresses normal output (quiet mode); the return status
indicates whether the _\bo_\bp_\bt_\bn_\ba_\bm_\be is set or unset. If multi-
ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return sta-
tus is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
not a directory is assumed to be the name of a variable
whose value is the directory to change to.
c\bcd\bds\bsp\bpe\bel\bll\bl If set, minor errors in the spelling of a directory com-
- ponent in a c\bcd\bd command will be corrected. The errors
+ ponent in a c\bcd\bd command will be corrected. The errors
checked for are transposed characters, a missing charac-
ter, and one character too many. If a correction is
found, the corrected filename is printed, and the com-
shells.
c\bch\bhe\bec\bck\bkh\bha\bas\bsh\bh
If set, b\bba\bas\bsh\bh checks that a command found in the hash ta-
- ble exists before trying to execute it. If a hashed
- command no longer exists, a normal path search is per-
+ ble exists before trying to execute it. If a hashed
+ command no longer exists, a normal path search is per-
formed.
c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs
If set, b\bba\bas\bsh\bh lists the status of any stopped and running
jobs before exiting an interactive shell. If any jobs
are running, this causes the exit to be deferred until a
- second exit is attempted without an intervening command
+ second exit is attempted without an intervening command
(see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL above). The shell always postpones ex-
iting if any jobs are stopped.
c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be
If set, b\bba\bas\bsh\bh quotes all shell metacharacters in file-
names and directory names when performing completion.
If not set, b\bba\bas\bsh\bh removes metacharacters such as the dol-
- lar sign from the set of characters that will be quoted
- in completed filenames when these metacharacters appear
- in shell variable references in words to be completed.
- This means that dollar signs in variable names that ex-
- pand to directories will not be quoted; however, any
- dollar signs appearing in filenames will not be quoted,
- either. This is active only when bash is using back-
- slashes to quote completed filenames. This variable is
- set by default, which is the default bash behavior in
+ lar sign from the set of characters that will be quoted
+ in completed filenames when these metacharacters appear
+ in shell variable references in words to be completed.
+ This means that dollar signs in variable names that ex-
+ pand to directories will not be quoted; however, any
+ dollar signs appearing in filenames will not be quoted,
+ either. This is active only when bash is using back-
+ slashes to quote completed filenames. This variable is
+ set by default, which is the default bash behavior in
versions through 4.2.
d\bdi\bir\bre\bex\bxp\bpa\ban\bnd\bd
- If set, b\bba\bas\bsh\bh replaces directory names with the results
- of word expansion when performing filename completion.
- This changes the contents of the readline editing buf-
- fer. If not set, b\bba\bas\bsh\bh attempts to preserve what the
+ If set, b\bba\bas\bsh\bh replaces directory names with the results
+ of word expansion when performing filename completion.
+ This changes the contents of the readline editing
+ buffer. If not set, b\bba\bas\bsh\bh attempts to preserve what the
user typed.
d\bdi\bir\brs\bsp\bpe\bel\bll\bl
- If set, b\bba\bas\bsh\bh attempts spelling correction on directory
- names during word completion if the directory name ini-
+ If set, b\bba\bas\bsh\bh attempts spelling correction on directory
+ names during word completion if the directory name ini-
tially supplied does not exist.
- d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a `.' in
- the results of pathname expansion. The filenames `\b``\b`.\b.'\b''\b'
- and `\b``\b`.\b..\b.'\b''\b' must always be matched explicitly, even if
- d\bdo\bot\btg\bgl\blo\bob\bb is set.
+ d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a "." in
+ the results of pathname expansion. The filenames "."
+ and ".." must always be matched explicitly, even if d\bdo\bot\bt-\b-
+ g\bgl\blo\bob\bb is set.
e\bex\bxe\bec\bcf\bfa\bai\bil\bl
If set, a non-interactive shell will not exit if it can-
- not execute the file specified as an argument to the
- e\bex\bxe\bec\bc builtin command. An interactive shell does not
+ not execute the file specified as an argument to the
+ e\bex\bxe\bec\bc builtin command. An interactive shell does not
exit if e\bex\bxe\bec\bc fails.
e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs
- If set, aliases are expanded as described above under
+ If set, aliases are expanded as described above under
A\bAL\bLI\bIA\bAS\bSE\bES\bS. This option is enabled by default for interac-
tive shells.
e\bex\bxt\btd\bde\beb\bbu\bug\bg
If set at shell invocation, or in a shell startup file,
arrange to execute the debugger profile before the shell
- starts, identical to the -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option. If set af-
- ter invocation, behavior intended for use by debuggers
+ starts, identical to the -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option. If set af-
+ ter invocation, behavior intended for use by debuggers
is enabled:
1\b1.\b. The -\b-F\bF option to the d\bde\bec\bcl\bla\bar\bre\be builtin displays the
source file name and line number corresponding to
each function name supplied as an argument.
- 2\b2.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
- non-zero value, the next command is skipped and
+ 2\b2.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
+ non-zero value, the next command is skipped and
not executed.
- 3\b3.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
- value of 2, and the shell is executing in a sub-
- routine (a shell function or a shell script exe-
- cuted by the .\b. or s\bso\bou\bur\brc\bce\be builtins), the shell
+ 3\b3.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
+ value of 2, and the shell is executing in a sub-
+ routine (a shell function or a shell script exe-
+ cuted by the .\b. or s\bso\bou\bur\brc\bce\be builtins), the shell
simulates a call to r\bre\bet\btu\bur\brn\bn.
- 4\b4.\b. B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
+ 4\b4.\b. B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
in their descriptions above).
- 5\b5.\b. Function tracing is enabled: command substitu-
+ 5\b5.\b. Function tracing is enabled: command substitu-
tion, shell functions, and subshells invoked with
(\b( _\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps.
above under P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn are enabled.
e\bex\bxt\btq\bqu\buo\bot\bte\be
- If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
- within $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b} expansions enclosed in double
+ If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
+ within $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b} expansions enclosed in double
quotes. This option is enabled by default.
f\bfa\bai\bil\blg\bgl\blo\bob\bb
- If set, patterns which fail to match filenames during
+ If set, patterns which fail to match filenames during
pathname expansion result in an expansion error.
f\bfo\bor\brc\bce\be_\b_f\bfi\big\bgn\bno\bor\bre\be
- If set, the suffixes specified by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
- variable cause words to be ignored when performing word
+ If set, the suffixes specified by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
+ variable cause words to be ignored when performing word
completion even if the ignored words are the only possi-
ble completions. See S\bSH\bHE\bEL\bLL\bL V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS above for a de-
scription of F\bFI\bIG\bGN\bNO\bOR\bRE\bE. This option is enabled by de-
g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs
If set, pathname expansion will never match the file-
- names `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b', even if the pattern begins with
- a `\b``\b`.\b.'\b''\b'. This option is enabled by default.
+ names "." and "..", even if the pattern begins with a
+ ".". This option is enabled by default.
g\bgl\blo\bob\bbs\bst\bta\bar\br
If set, the pattern *\b**\b* used in a pathname expansion con-
- text will match all files and zero or more directories
- and subdirectories. If the pattern is followed by a /\b/,
+ text will match all files and zero or more directories
+ and subdirectories. If the pattern is followed by a /\b/,
only directories and subdirectories match.
g\bgn\bnu\bu_\b_e\ber\brr\brf\bfm\bmt\bt
its, rather than overwriting the file.
h\bhi\bis\bst\btr\bre\bee\bed\bdi\bit\bt
- If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, a user is given the
+ If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, a user is given the
opportunity to re-edit a failed history substitution.
h\bhi\bis\bst\btv\bve\ber\bri\bif\bfy\by
- If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, the results of his-
- tory substitution are not immediately passed to the
- shell parser. Instead, the resulting line is loaded
+ If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, the results of his-
+ tory substitution are not immediately passed to the
+ shell parser. Instead, the resulting line is loaded
into the r\bre\bea\bad\bdl\bli\bin\bne\be editing buffer, allowing further modi-
fication.
h\bho\bos\bst\btc\bco\bom\bmp\bpl\ble\bet\bte\be
If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will attempt to
- perform hostname completion when a word containing a @\b@
- is being completed (see C\bCo\bom\bmp\bpl\ble\bet\bti\bin\bng\bg under R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE
+ perform hostname completion when a word containing a @\b@
+ is being completed (see C\bCo\bom\bmp\bpl\ble\bet\bti\bin\bng\bg under R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE
above). This is enabled by default.
h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt
i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs
If set, allow a word beginning with #\b# to cause that word
- and all remaining characters on that line to be ignored
- in an interactive shell (see C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS above). This op-
+ and all remaining characters on that line to be ignored
+ in an interactive shell (see C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS above). This op-
tion is enabled by default.
l\bla\bas\bst\btp\bpi\bip\bpe\be
- If set, and job control is not active, the shell runs
+ If set, and job control is not active, the shell runs
the last command of a pipeline not executed in the back-
ground in the current shell environment.
m\bma\bai\bil\blw\bwa\bar\brn\bn
If set, and a file that b\bba\bas\bsh\bh is checking for mail has
- been accessed since the last time it was checked, the
- message ``The mail in _\bm_\ba_\bi_\bl_\bf_\bi_\bl_\be has been read'' is dis-
- played.
+ been accessed since the last time it was checked, b\bba\bas\bsh\bh
+ displays the message "The mail in _\bm_\ba_\bi_\bl_\bf_\bi_\bl_\be has been
+ read".
n\bno\bo_\b_e\bem\bmp\bpt\bty\by_\b_c\bcm\bmd\bd_\b_c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn
If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will not at-
E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn above).
n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh
- If set, b\bba\bas\bsh\bh matches patterns in a case-insensitive
+ If set, b\bba\bas\bsh\bh matches patterns in a case-insensitive
fashion when performing matching while executing c\bca\bas\bse\be or
[\b[[\b[ conditional commands, when performing pattern substi-
- tution word expansions, or when filtering possible com-
+ tution word expansions, or when filtering possible com-
pletions as part of programmable completion.
n\bno\boe\bex\bxp\bpa\ban\bnd\bd_\b_t\btr\bra\ban\bns\bsl\bla\bat\bti\bio\bon\bn
- If set, b\bba\bas\bsh\bh encloses the translated results of $"..."
- quoting in single quotes instead of double quotes. If
+ If set, b\bba\bas\bsh\bh encloses the translated results of $\b$"\b"..."\b"
+ quoting in single quotes instead of double quotes. If
the string is not translated, this has no effect.
n\bnu\bul\bll\blg\bgl\blo\bob\bb
p\bpr\bro\bom\bmp\bpt\btv\bva\bar\brs\bs
If set, prompt strings undergo parameter expansion, com-
- mand substitution, arithmetic expansion, and quote re-
- moval after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG
+ mand substitution, arithmetic expansion, and quote re-
+ moval after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG
above. This option is enabled by default.
r\bre\bes\bst\btr\bri\bic\bct\bte\bed\bd_\b_s\bsh\bhe\bel\bll\bl
- The shell sets this option if it is started in re-
- stricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL below). The value
- may not be changed. This is not reset when the startup
- files are executed, allowing the startup files to dis-
+ The shell sets this option if it is started in re-
+ stricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL below). The value
+ may not be changed. This is not reset when the startup
+ files are executed, allowing the startup files to dis-
cover whether or not a shell is restricted.
s\bsh\bhi\bif\bft\bt_\b_v\bve\ber\brb\bbo\bos\bse\be
- If set, the s\bsh\bhi\bif\bft\bt builtin prints an error message when
+ If set, the s\bsh\bhi\bif\bft\bt builtin prints an error message when
the shift count exceeds the number of positional parame-
ters.
s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh
If set, the .\b. (s\bso\bou\bur\brc\bce\be) builtin uses the value of P\bPA\bAT\bTH\bH to
- find the directory containing the file supplied as an
+ find the directory containing the file supplied as an
argument. This option is enabled by default.
v\bva\bar\brr\bre\bed\bdi\bir\br_\b_c\bcl\blo\bos\bse\be
- If set, the shell automatically closes file descriptors
- assigned using the _\b{_\bv_\ba_\br_\bn_\ba_\bm_\be_\b} redirection syntax (see R\bRE\bE-\b-
- D\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN above) instead of leaving them open when the
+ If set, the shell automatically closes file descriptors
+ assigned using the _\b{_\bv_\ba_\br_\bn_\ba_\bm_\be_\b} redirection syntax (see
+ R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN above) instead of leaving them open when the
command completes.
x\bxp\bpg\bg_\b_e\bec\bch\bho\bo
t\bte\bes\bst\bt _\be_\bx_\bp_\br
[\b[ _\be_\bx_\bp_\br ]\b]
Return a status of 0 (true) or 1 (false) depending on the evalu-
- ation of the conditional expression _\be_\bx_\bp_\br. Each operator and op-
- erand must be a separate argument. Expressions are composed of
- the primaries described above under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS.
- t\bte\bes\bst\bt does not accept any options, nor does it accept and ignore
+ ation of the conditional expression _\be_\bx_\bp_\br. Each operator and
+ operand must be a separate argument. Expressions are composed
+ of the primaries described above under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS.
+ t\bte\bes\bst\bt does not accept any options, nor does it accept and ignore
an argument of -\b--\b- as signifying the end of options.
- Expressions may be combined using the following operators,
- listed in decreasing order of precedence. The evaluation de-
- pends on the number of arguments; see below. Operator prece-
+ Expressions may be combined using the following operators,
+ listed in decreasing order of precedence. The evaluation de-
+ pends on the number of arguments; see below. Operator prece-
dence is used when there are five or more arguments.
!\b! _\be_\bx_\bp_\br True if _\be_\bx_\bp_\br is false.
(\b( _\be_\bx_\bp_\br )\b)
- Returns the value of _\be_\bx_\bp_\br. This may be used to override
+ Returns the value of _\be_\bx_\bp_\br. This may be used to override
the normal precedence of operators.
_\be_\bx_\bp_\br_\b1 -a\ba _\be_\bx_\bp_\br_\b2
True if both _\be_\bx_\bp_\br_\b1 and _\be_\bx_\bp_\br_\b2 are true.
false.
3 arguments
The following conditions are applied in the order listed.
- If the second argument is one of the binary conditional
+ If the second argument is one of the binary conditional
operators listed above under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS, the
result of the expression is the result of the binary test
- using the first and third arguments as operands. The -\b-a\ba
- and -\b-o\bo operators are considered binary operators when
- there are three arguments. If the first argument is !\b!,
- the value is the negation of the two-argument test using
+ using the first and third arguments as operands. The -\b-a\ba
+ and -\b-o\bo operators are considered binary operators when
+ there are three arguments. If the first argument is !\b!,
+ the value is the negation of the two-argument test using
the second and third arguments. If the first argument is
exactly (\b( and the third argument is exactly )\b), the result
- is the one-argument test of the second argument. Other-
+ is the one-argument test of the second argument. Other-
wise, the expression is false.
4 arguments
The following conditions are applied in the order listed.
If the first argument is !\b!, the result is the negation of
- the three-argument expression composed of the remaining
- arguments. the two-argument test using the second and
- third arguments. If the first argument is exactly (\b( and
- the fourth argument is exactly )\b), the result is the two-
- argument test of the second and third arguments. Other-
+ the three-argument expression composed of the remaining
+ arguments. the two-argument test using the second and
+ third arguments. If the first argument is exactly (\b( and
+ the fourth argument is exactly )\b), the result is the two-
+ argument test of the second and third arguments. Other-
wise, the expression is parsed and evaluated according to
precedence using the rules listed above.
5 or more arguments
The expression is parsed and evaluated according to
precedence using the rules listed above.
- If the shell is not in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, when used with t\bte\bes\bst\bt or [\b[, the
- <\b< and >\b> operators sort lexicographically using ASCII ordering.
- When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, these operators sort using the
- current locale.
+ When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, or if the expression is part of
+ the [\b[[\b[ command, the <\b< and >\b> operators sort using the current lo-
+ cale. If the shell is not in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, the t\bte\bes\bst\bt and [\b[ com-
+ mands sort lexicographically using ASCII ordering.
t\bti\bim\bme\bes\bs Print the accumulated user and system times for the shell and
for processes run from the shell. The return status is 0.
If no arguments are supplied, t\btr\bra\bap\bp displays the actions associ-
ated with each trapped signal as a set of t\btr\bra\bap\bp commands that can
- be reused as shell input to restore the current signal disposi-
- tions. If -\b-p\bp is given, and _\ba_\bc_\bt_\bi_\bo_\bn is not present, then t\btr\bra\bap\bp
- displays the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc or, if none
+ be reused as shell input to restore the current signal disposi-
+ tions. If -\b-p\bp is given, and _\ba_\bc_\bt_\bi_\bo_\bn is not present, then t\btr\bra\bap\bp
+ displays the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc or, if none
are supplied, for all trapped signals, as a set of t\btr\bra\bap\bp commands
that can be reused as shell input to restore the current signal
dispositions. The -\b-P\bP option behaves similarly, but displays
If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bEX\bXI\bIT\bT (0) the command _\ba_\bc_\bt_\bi_\bo_\bn is executed on exit
from the shell. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is D\bDE\bEB\bBU\bUG\bG, the command _\ba_\bc_\bt_\bi_\bo_\bn is
executed before every _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, _\bf_\bo_\br command, _\bc_\ba_\bs_\be command,
- _\bs_\be_\bl_\be_\bc_\bt command, (( arithmetic command, [[ conditional command,
+ _\bs_\be_\bl_\be_\bc_\bt command, (( arithmetic command, [[ conditional command,
arithmetic _\bf_\bo_\br command, and before the first command executes in
a shell function (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR above). Refer to the de-
scription of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin for de-
or a compound command returns a non-zero exit status, subject to
the following conditions. The E\bER\bRR\bR trap is not executed if the
failed command is part of the command list immediately following
- a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an _\bi_\bf statement,
+ a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an _\bi_\bf statement,
part of a command executed in a &\b&&\b& or |\b||\b| list except the command
following the final &\b&&\b& or |\b||\b|, any command in a pipeline but the
last, or if the command's return value is being inverted using
t\bty\byp\bpe\be [-\b-a\baf\bft\btp\bpP\bP] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
With no options, indicate how each _\bn_\ba_\bm_\be would be interpreted if
used as a command name. If the -\b-t\bt option is used, t\bty\byp\bpe\be prints a
- string which is one of _\ba_\bl_\bi_\ba_\bs, _\bk_\be_\by_\bw_\bo_\br_\bd, _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn, _\bb_\bu_\bi_\bl_\bt_\bi_\bn, or
- _\bf_\bi_\bl_\be if _\bn_\ba_\bm_\be is an alias, shell reserved word, function,
- builtin, or executable disk file, respectively. If the _\bn_\ba_\bm_\be is
- not found, then nothing is printed, and t\bty\byp\bpe\be returns a non-zero
- exit status. If the -\b-p\bp option is used, t\bty\byp\bpe\be either returns the
- name of the executable file that would be found by searching
- $\b$P\bPA\bAT\bTH\bH if _\bn_\ba_\bm_\be were specified as a command name, or nothing if
- ``type -t name'' would not return _\bf_\bi_\bl_\be. The -\b-P\bP option forces a
- P\bPA\bAT\bTH\bH search for each _\bn_\ba_\bm_\be, even if ``type -t name'' would not
- return _\bf_\bi_\bl_\be. If a command is hashed, -\b-p\bp and -\b-P\bP print the hashed
- value, which is not necessarily the file that appears first in
- P\bPA\bAT\bTH\bH. If the -\b-a\ba option is used, t\bty\byp\bpe\be prints all of the places
- that contain a command named _\bn_\ba_\bm_\be. This includes aliases, re-
- served words, functions, and builtins, but the path search op-
+ string which is one of _\ba_\bl_\bi_\ba_\bs, _\bk_\be_\by_\bw_\bo_\br_\bd, _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn, _\bb_\bu_\bi_\bl_\bt_\bi_\bn, or
+ _\bf_\bi_\bl_\be if _\bn_\ba_\bm_\be is an alias, shell reserved word, function,
+ builtin, or executable disk file, respectively. If the _\bn_\ba_\bm_\be is
+ not found, then nothing is printed, and t\bty\byp\bpe\be returns a non-zero
+ exit status. If the -\b-p\bp option is used, t\bty\byp\bpe\be either returns the
+ name of the executable file that would be found by searching
+ $\b$P\bPA\bAT\bTH\bH if _\bn_\ba_\bm_\be were specified as a command name, or nothing if
+ "type -t name" would not return _\bf_\bi_\bl_\be. The -\b-P\bP option forces a
+ P\bPA\bAT\bTH\bH search for each _\bn_\ba_\bm_\be, even if "type -t name" would not re-
+ turn _\bf_\bi_\bl_\be. If a command is hashed, -\b-p\bp and -\b-P\bP print the hashed
+ value, which is not necessarily the file that appears first in
+ P\bPA\bAT\bTH\bH. If the -\b-a\ba option is used, t\bty\byp\bpe\be prints all of the places
+ that contain a command named _\bn_\ba_\bm_\be. This includes aliases, re-
+ served words, functions, and builtins, but the path search op-
tions (-\b-p\bp and -\b-P\bP) can be supplied to restrict the output to exe-
cutable files. t\bty\byp\bpe\be does not consult the table of hashed com-
mands when using -\b-a\ba with -\b-p\bp, and only performs a P\bPA\bAT\bTH\bH search for
- _\bn_\ba_\bm_\be. The -\b-f\bf option suppresses shell function lookup, as with
- the c\bco\bom\bmm\bma\ban\bnd\bd builtin. t\bty\byp\bpe\be returns true if all of the arguments
+ _\bn_\ba_\bm_\be. The -\b-f\bf option suppresses shell function lookup, as with
+ the c\bco\bom\bmm\bma\ban\bnd\bd builtin. t\bty\byp\bpe\be returns true if all of the arguments
are found, false if any are not found.
u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bS] -\b-a\ba
u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bS] [-\b-b\bbc\bcd\bde\bef\bfi\bik\bkl\blm\bmn\bnp\bpq\bqr\brs\bst\btu\buv\bvx\bxP\bPR\bRT\bT [_\bl_\bi_\bm_\bi_\bt]]
- Provides control over the resources available to the shell and
- to processes started by it, on systems that allow such control.
+ Provides control over the resources available to the shell and
+ to processes started by it, on systems that allow such control.
The -\b-H\bH and -\b-S\bS options specify that the hard or soft limit is set
for the given resource. A hard limit cannot be increased by a
non-root user once it is set; a soft limit may be increased up
fied, both the soft and hard limits are set. The value of _\bl_\bi_\bm_\bi_\bt
can be a number in the unit specified for the resource or one of
the special values h\bha\bar\brd\bd, s\bso\bof\bft\bt, or u\bun\bnl\bli\bim\bmi\bit\bte\bed\bd, which stand for the
- current hard limit, the current soft limit, and no limit, re-
- spectively. If _\bl_\bi_\bm_\bi_\bt is omitted, the current value of the soft
+ current hard limit, the current soft limit, and no limit, re-
+ spectively. If _\bl_\bi_\bm_\bi_\bt is omitted, the current value of the soft
limit of the resource is printed, unless the -\b-H\bH option is given.
When more than one resource is specified, the limit name and
unit, if appropriate, are printed before the value. Other op-
-\b-b\bb The maximum socket buffer size
-\b-c\bc The maximum size of core files created
-\b-d\bd The maximum size of a process's data segment
- -\b-e\be The maximum scheduling priority ("nice")
+ -\b-e\be The maximum scheduling priority ("nice").
-\b-f\bf The maximum size of files written by the shell and its
children
-\b-i\bi The maximum number of pending signals
-\b-r\br The maximum real-time scheduling priority
-\b-s\bs The maximum stack size
-\b-t\bt The maximum amount of cpu time in seconds
- -\b-u\bu The maximum number of processes available to a single
+ -\b-u\bu The maximum number of processes available to a single
user
- -\b-v\bv The maximum amount of virtual memory available to the
+ -\b-v\bv The maximum amount of virtual memory available to the
shell and, on some systems, to its children
-\b-x\bx The maximum number of file locks
-\b-P\bP The maximum number of pseudoterminals
- -\b-R\bR The maximum time a real-time process can run before
+ -\b-R\bR The maximum time a real-time process can run before
blocking, in microseconds
-\b-T\bT The maximum number of threads
- If _\bl_\bi_\bm_\bi_\bt is given, and the -\b-a\ba option is not used, _\bl_\bi_\bm_\bi_\bt is the
- new value of the specified resource. If no option is given,
- then -\b-f\bf is assumed. Values are in 1024-byte increments, except
- for -\b-t\bt, which is in seconds; -\b-R\bR, which is in microseconds; -\b-p\bp,
- which is in units of 512-byte blocks; -\b-P\bP, -\b-T\bT, -\b-b\bb, -\b-k\bk, -\b-n\bn, and
- -\b-u\bu, which are unscaled values; and, when in posix mode, -\b-c\bc and
- -\b-f\bf, which are in 512-byte increments. The return status is 0
- unless an invalid option or argument is supplied, or an error
+ If _\bl_\bi_\bm_\bi_\bt is given, and the -\b-a\ba option is not used, _\bl_\bi_\bm_\bi_\bt is the
+ new value of the specified resource. If no option is given,
+ then -\b-f\bf is assumed. Values are in 1024-byte increments, except
+ for -\b-t\bt, which is in seconds; -\b-R\bR, which is in microseconds; -\b-p\bp,
+ which is in units of 512-byte blocks; -\b-P\bP, -\b-T\bT, -\b-b\bb, -\b-k\bk, -\b-n\bn, and
+ -\b-u\bu, which are unscaled values; and, when in posix mode, -\b-c\bc and
+ -\b-f\bf, which are in 512-byte increments. The return status is 0
+ unless an invalid option or argument is supplied, or an error
occurs while setting a new limit.
u\bum\bma\bas\bsk\bk [-\b-p\bp] [-\b-S\bS] [_\bm_\bo_\bd_\be]
u\bun\bns\bse\bet\bt [-f\bfv\bv] [-n\bn] [_\bn_\ba_\bm_\be ...]
For each _\bn_\ba_\bm_\be, remove the corresponding variable or function.
If the -\b-v\bv option is given, each _\bn_\ba_\bm_\be refers to a shell variable,
- and that variable is removed. Read-only variables may not be
- unset. If -\b-f\bf is specified, each _\bn_\ba_\bm_\be refers to a shell func-
- tion, and the function definition is removed. If the -\b-n\bn option
- is supplied, and _\bn_\ba_\bm_\be is a variable with the _\bn_\ba_\bm_\be_\br_\be_\bf attribute,
- _\bn_\ba_\bm_\be will be unset rather than the variable it references. -\b-n\bn
- has no effect if the -\b-f\bf option is supplied. If no options are
- supplied, each _\bn_\ba_\bm_\be refers to a variable; if there is no vari-
- able by that name, a function with that name, if any, is unset.
- Each unset variable or function is removed from the environment
- passed to subsequent commands. If any of B\bBA\bAS\bSH\bH_\b_A\bAL\bLI\bIA\bAS\bSE\bES\bS,
+ and that variable is removed. Read-only variables may not be
+ unset. If -\b-f\bf is specified, each _\bn_\ba_\bm_\be refers to a shell func-
+ tion, and the function definition is removed. If the -\b-n\bn option
+ is supplied, and _\bn_\ba_\bm_\be is a variable with the _\bn_\ba_\bm_\be_\br_\be_\bf attribute,
+ _\bn_\ba_\bm_\be will be unset rather than the variable it references. -\b-n\bn
+ has no effect if the -\b-f\bf option is supplied. If no options are
+ supplied, each _\bn_\ba_\bm_\be refers to a variable; if there is no vari-
+ able by that name, a function with that name, if any, is unset.
+ Each unset variable or function is removed from the environment
+ passed to subsequent commands. If any of B\bBA\bAS\bSH\bH_\b_A\bAL\bLI\bIA\bAS\bSE\bES\bS,
B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0, B\bBA\bAS\bSH\bH_\b_C\bCM\bMD\bDS\bS, B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD, B\bBA\bAS\bSH\bH_\b_S\bSU\bUB\bBS\bSH\bHE\bEL\bLL\bL, B\bBA\bAS\bSH\bHP\bPI\bID\bD,
- C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS, D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK, E\bEP\bPO\bOC\bCH\bHR\bRE\bEA\bAL\bLT\bTI\bIM\bME\bE, E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS, F\bFU\bUN\bNC\bC-\b-
- N\bNA\bAM\bME\bE, G\bGR\bRO\bOU\bUP\bPS\bS, H\bHI\bIS\bST\bTC\bCM\bMD\bD, L\bLI\bIN\bNE\bEN\bNO\bO, R\bRA\bAN\bND\bDO\bOM\bM, S\bSE\bEC\bCO\bON\bND\bDS\bS, or S\bSR\bRA\bAN\bND\bDO\bOM\bM are
+ C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS, D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK, E\bEP\bPO\bOC\bCH\bHR\bRE\bEA\bAL\bLT\bTI\bIM\bME\bE, E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS, F\bFU\bUN\bNC\bC-\b-
+ N\bNA\bAM\bME\bE, G\bGR\bRO\bOU\bUP\bPS\bS, H\bHI\bIS\bST\bTC\bCM\bMD\bD, L\bLI\bIN\bNE\bEN\bNO\bO, R\bRA\bAN\bND\bDO\bOM\bM, S\bSE\bEC\bCO\bON\bND\bDS\bS, or S\bSR\bRA\bAN\bND\bDO\bOM\bM are
unset, they lose their special properties, even if they are sub-
sequently reset. The exit status is true unless a _\bn_\ba_\bm_\be is read-
only or may not be unset.
- w\bwa\bai\bit\bt [-\b-f\bfn\bn] [-\b-p\bp _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bi_\bd _\b._\b._\b.]
+ w\bwa\bai\bit\bt [-\b-f\bfn\bn] [-\b-p\bp _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bi_\bd ...]
Wait for each specified child process and return its termination
status. Each _\bi_\bd may be a process ID or a job specification; if
a job spec is given, all processes in that job's pipeline are
waited for. If _\bi_\bd is not given, w\bwa\bai\bit\bt waits for all running
background jobs and the last-executed process substitution, if
its process id is the same as $\b$!\b!, and the return status is zero.
- If the -\b-n\bn option is supplied, w\bwa\bai\bit\bt waits for a single job from
+ If the -\b-n\bn option is supplied, w\bwa\bai\bit\bt waits for a single job from
the list of _\bi_\bds or, if no _\bi_\bds are supplied, any job, to complete
and returns its exit status. If none of the supplied arguments
is a child of the shell, or if no arguments are supplied and the
- shell has no unwaited-for children, the exit status is 127. If
- the -\b-p\bp option is supplied, the process or job identifier of the
- job for which the exit status is returned is assigned to the
- variable _\bv_\ba_\br_\bn_\ba_\bm_\be named by the option argument. The variable
- will be unset initially, before any assignment. This is useful
- only when the -\b-n\bn option is supplied. Supplying the -\b-f\bf option,
- when job control is enabled, forces w\bwa\bai\bit\bt to wait for _\bi_\bd to ter-
+ shell has no unwaited-for children, the exit status is 127. If
+ the -\b-p\bp option is supplied, the process or job identifier of the
+ job for which the exit status is returned is assigned to the
+ variable _\bv_\ba_\br_\bn_\ba_\bm_\be named by the option argument. The variable
+ will be unset initially, before any assignment. This is useful
+ only when the -\b-n\bn option is supplied. Supplying the -\b-f\bf option,
+ when job control is enabled, forces w\bwa\bai\bit\bt to wait for _\bi_\bd to ter-
minate before returning its status, instead of returning when it
changes status. If _\bi_\bd specifies a non-existent process or job,
the return status is 127. If w\bwa\bai\bit\bt is interrupted by a signal,
S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE
Bash-4.0 introduced the concept of a _\bs_\bh_\be_\bl_\bl _\bc_\bo_\bm_\bp_\ba_\bt_\bi_\bb_\bi_\bl_\bi_\bt_\by _\bl_\be_\bv_\be_\bl, speci-
- fied as a set of options to the shopt builtin ( c\bco\bom\bmp\bpa\bat\bt3\b31\b1, c\bco\bom\bmp\bpa\bat\bt3\b32\b2,
- c\bco\bom\bmp\bpa\bat\bt4\b40\b0, c\bco\bom\bmp\bpa\bat\bt4\b41\b1, and so on). There is only one current compatibil-
- ity level -- each option is mutually exclusive. The compatibility
- level is intended to allow users to select behavior from previous ver-
- sions that is incompatible with newer versions while they migrate
- scripts to use current features and behavior. It's intended to be a
- temporary solution.
+ fied as a set of options to the shopt builtin (c\bco\bom\bmp\bpa\bat\bt3\b31\b1, c\bco\bom\bmp\bpa\bat\bt3\b32\b2, c\bco\bom\bm-\b-
+ p\bpa\bat\bt4\b40\b0, c\bco\bom\bmp\bpa\bat\bt4\b41\b1, and so on). There is only one current compatibility
+ level -- each option is mutually exclusive. The compatibility level is
+ intended to allow users to select behavior from previous versions that
+ is incompatible with newer versions while they migrate scripts to use
+ current features and behavior. It's intended to be a temporary solu-
+ tion.
This section does not mention behavior that is standard for a particu-
lar version (e.g., setting c\bco\bom\bmp\bpa\bat\bt3\b32\b2 means that quoting the rhs of the
present in earlier versions. For instance, the change to use locale-
based comparisons with the [\b[[\b[ command came in bash-4.1, and earlier
versions used ASCII-based comparisons, so enabling c\bco\bom\bmp\bpa\bat\bt3\b32\b2 will enable
- ASCII-based comparisons as well. That granularity may not be suffi-
- cient for all uses, and as a result users should employ compatibility
- levels carefully. Read the documentation for a particular feature to
+ ASCII-based comparisons as well. That granularity may not be suffi-
+ cient for all uses, and as a result users should employ compatibility
+ levels carefully. Read the documentation for a particular feature to
find out the current behavior.
- Bash-4.3 introduced a new shell variable: B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT. The value as-
+ Bash-4.3 introduced a new shell variable: B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT. The value as-
signed to this variable (a decimal version number like 4.2, or an inte-
ger corresponding to the c\bco\bom\bmp\bpa\bat\bt_\bN_\bN option, like 42) determines the com-
patibility level.
shopt option for the previous version. Users should control the compat-
ibility level with B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT.
- The following table describes the behavior changes controlled by each
+ The following table describes the behavior changes controlled by each
compatibility level setting. The c\bco\bom\bmp\bpa\bat\bt_\bN_\bN tag is used as shorthand for
setting the compatibility level to _\bN_\bN using one of the following mecha-
- nisms. For versions prior to bash-5.0, the compatibility level may be
- set using the corresponding c\bco\bom\bmp\bpa\bat\bt_\bN_\bN shopt option. For bash-4.3 and
- later versions, the B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT variable is preferred, and it is re-
+ nisms. For versions prior to bash-5.0, the compatibility level may be
+ set using the corresponding c\bco\bom\bmp\bpa\bat\bt_\bN_\bN shopt option. For bash-4.3 and
+ later versions, the B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT variable is preferred, and it is re-
quired for bash-5.1 and later versions.
c\bco\bom\bmp\bpa\bat\bt3\b31\b1
ordering.
c\bco\bom\bmp\bpa\bat\bt4\b40\b0
- +\bo the <\b< and >\b> operators to the [\b[[\b[ command do not consider
+ +\bo the <\b< and >\b> operators to the [\b[[\b[ command do not consider
the current locale when comparing strings; they use ASCII
ordering. B\bBa\bas\bsh\bh versions prior to bash-4.1 use ASCII col-
- lation and _\bs_\bt_\br_\bc_\bm_\bp(3); bash-4.1 and later use the current
+ lation and _\bs_\bt_\br_\bc_\bm_\bp(3); bash-4.1 and later use the current
locale's collation sequence and _\bs_\bt_\br_\bc_\bo_\bl_\bl(3).
c\bco\bom\bmp\bpa\bat\bt4\b41\b1
- +\bo in _\bp_\bo_\bs_\bi_\bx mode, t\bti\bim\bme\be may be followed by options and still
+ +\bo in _\bp_\bo_\bs_\bi_\bx mode, t\bti\bim\bme\be may be followed by options and still
be recognized as a reserved word (this is POSIX interpre-
tation 267)
+\bo in _\bp_\bo_\bs_\bi_\bx mode, the parser requires that an even number of
- single quotes occur in the _\bw_\bo_\br_\bd portion of a double-
- quoted parameter expansion and treats them specially, so
- that characters within the single quotes are considered
+ single quotes occur in the _\bw_\bo_\br_\bd portion of a double-
+ quoted parameter expansion and treats them specially, so
+ that characters within the single quotes are considered
quoted (this is POSIX interpretation 221)
c\bco\bom\bmp\bpa\bat\bt4\b42\b2
c\bco\bom\bmp\bpa\bat\bt5\b50\b0
+\bo Bash-5.1 changed the way $\b$R\bRA\bAN\bND\bDO\bOM\bM is generated to intro-
duce slightly more randomness. If the shell compatibility
- level is set to 50 or lower, it reverts to the method
- from bash-5.0 and previous versions, so seeding the ran-
- dom number generator by assigning a value to R\bRA\bAN\bND\bDO\bOM\bM will
+ level is set to 50 or lower, it reverts to the method
+ from bash-5.0 and previous versions, so seeding the ran-
+ dom number generator by assigning a value to R\bRA\bAN\bND\bDO\bOM\bM will
produce the same sequence as in bash-5.0
- +\bo If the command hash table is empty, bash versions prior
- to bash-5.1 printed an informational message to that ef-
- fect, even when producing output that can be reused as
- input. Bash-5.1 suppresses that message when the -\b-l\bl op-
+ +\bo If the command hash table is empty, bash versions prior
+ to bash-5.1 printed an informational message to that ef-
+ fect, even when producing output that can be reused as
+ input. Bash-5.1 suppresses that message when the -\b-l\bl op-
tion is supplied.
c\bco\bom\bmp\bpa\bat\bt5\b51\b1
- +\bo The u\bun\bns\bse\bet\bt builtin treats attempts to unset array sub-
- scripts @\b@ and *\b* differently depending on whether the ar-
- ray is indexed or associative, and differently than in
+ +\bo The u\bun\bns\bse\bet\bt builtin treats attempts to unset array sub-
+ scripts @\b@ and *\b* differently depending on whether the ar-
+ ray is indexed or associative, and differently than in
previous versions.
- +\bo arithmetic commands ( ((...)) ) and the expressions in an
+ +\bo arithmetic commands ( (\b((\b(...)\b))\b) ) and the expressions in an
arithmetic for statement can be expanded more than once
+\bo expressions used as arguments to arithmetic operators in
the [\b[[\b[ conditional command can be expanded more than once
+\bo the expressions in substring parameter brace expansion
can be expanded more than once
- +\bo the expressions in the $(( ... )) word expansion can be
- expanded more than once
- +\bo arithmetic expressions used as indexed array subscripts
+ +\bo the expressions in the $\b$(\b((\b(...)\b))\b) word expansion can be ex-
+ panded more than once
+ +\bo arithmetic expressions used as indexed array subscripts
can be expanded more than once
- +\bo t\bte\bes\bst\bt -\b-v\bv, when given an argument of A\bA[\b[@\b@]\b], where A\bAP\bP i\bis\bs a\ban\bn
- e\bex\bxi\bis\bst\bti\bin\bng\bg a\bas\bss\bso\boc\bci\bia\bat\bti\biv\bve\be a\bar\brr\bra\bay\by,\b, w\bwi\bil\bll\bl r\bre\bet\btu\bur\brn\bn t\btr\bru\bue\be i\bif\bf t\bth\bhe\be a\bar\brr\bra\bay\by
- h\bha\bas\bs a\ban\bny\by s\bse\bet\bt e\bel\ble\bem\bme\ben\bnt\bts\bs.\b. B\bBa\bas\bsh\bh-\b-5\b5.\b.2\b2 w\bwi\bil\bll\bl l\blo\boo\bok\bk f\bfo\bor\br a\ban\bnd\bd r\bre\bep\bpo\bor\brt\bt
- o\bon\bn a\ba k\bke\bey\by n\bna\bam\bme\bed\bd @\b@.\b.
- +\b+\bo\bo the ${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br[\b[:\b:]\b]=\b=_\bv_\ba_\bl_\bu_\be} word expansion will return
+ +\bo t\bte\bes\bst\bt -\b-v\bv, when given an argument of A\bA[\b[@\b@]\b], where A\bA is an
+ existing associative array, will return true if the array
+ has any set elements. Bash-5.2 will look for and report
+ on a key named @\b@.
+ +\bo the ${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br[\b[:\b:]\b]=\b=_\bv_\ba_\bl_\bu_\be} word expansion will return
_\bv_\ba_\bl_\bu_\be, before any variable-specific transformations have
been performed (e.g., converting to lowercase). Bash-5.2
will return the final value assigned to the variable.
- +\bo Parsing command substitutions will behave as if extended
+ +\bo Parsing command substitutions will behave as if extended
globbing (see the description of the s\bsh\bho\bop\bpt\bt builtin above)
is enabled, so that parsing a command substitution con-
taining an extglob pattern (say, as part of a shell func-
- tion) will not fail. This assumes the intent is to en-
- able extglob before the command is executed and word ex-
- pansions are performed. It will fail at word expansion
- time if extglob hasn't been enabled by the time the com-
+ tion) will not fail. This assumes the intent is to en-
+ able extglob before the command is executed and word ex-
+ pansions are performed. It will fail at word expansion
+ time if extglob hasn't been enabled by the time the com-
mand is executed.
R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL
+\bo parsing the value of S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS from the shell environment at
startup
- +\bo redirecting output using the >, >|, <>, >&, &>, and >> redirect-
- ion operators
+ +\bo redirecting output using the >, >|, <>, >&, &>, and >> redirec-
+ tion operators
+\bo using the e\bex\bxe\bec\bc builtin command to replace the shell with another
command
- +\bo adding or deleting builtin commands with the -\b-f\bf and -\b-d\bd options
+ +\bo adding or deleting builtin commands with the -\b-f\bf and -\b-d\bd options
to the e\ben\bna\bab\bbl\ble\be builtin command
- +\bo using the e\ben\bna\bab\bbl\ble\be builtin command to enable disabled shell
+ +\bo using the e\ben\bna\bab\bbl\ble\be builtin command to enable disabled shell
builtins
+\bo specifying the -\b-p\bp option to the c\bco\bom\bmm\bma\ban\bnd\bd builtin command
- +\bo turning off restricted mode with s\bse\bet\bt +\b+r\br or s\bsh\bho\bop\bpt\bt -\b-u\bu r\bre\be-\b-
+ +\bo turning off restricted mode with s\bse\bet\bt +\b+r\br or s\bsh\bho\bop\bpt\bt -\b-u\bu r\bre\be-\b-
s\bst\btr\bri\bic\bct\bte\bed\bd_\b_s\bsh\bhe\bel\bll\bl.
These restrictions are enforced after any startup files are read.
_\bB_\ba_\bs_\bh _\bR_\be_\bf_\be_\br_\be_\bn_\bc_\be _\bM_\ba_\bn_\bu_\ba_\bl, Brian Fox and Chet Ramey
_\bT_\bh_\be _\bG_\bn_\bu _\bR_\be_\ba_\bd_\bl_\bi_\bn_\be _\bL_\bi_\bb_\br_\ba_\br_\by, Brian Fox and Chet Ramey
_\bT_\bh_\be _\bG_\bn_\bu _\bH_\bi_\bs_\bt_\bo_\br_\by _\bL_\bi_\bb_\br_\ba_\br_\by, Brian Fox and Chet Ramey
- _\bP_\bo_\br_\bt_\ba_\bb_\bl_\be _\bO_\bp_\be_\br_\ba_\bt_\bi_\bn_\bg _\bS_\by_\bs_\bt_\be_\bm _\bI_\bn_\bt_\be_\br_\bf_\ba_\bc_\be _\b(_\bP_\bO_\bS_\bI_\bX_\b) _\bP_\ba_\br_\bt _\b2_\b: _\bS_\bh_\be_\bl_\bl _\ba_\bn_\bd _\bU_\bt_\bi_\bl_\bi_\b-
+ _\bP_\bo_\br_\bt_\ba_\bb_\bl_\be _\bO_\bp_\be_\br_\ba_\bt_\bi_\bn_\bg _\bS_\by_\bs_\bt_\be_\bm _\bI_\bn_\bt_\be_\br_\bf_\ba_\bc_\be _\b(_\bP_\bO_\bS_\bI_\bX_\b) _\bP_\ba_\br_\bt _\b2_\b: _\bS_\bh_\be_\bl_\bl _\ba_\bn_\bd _\bU_\bt_\bi_\bl_\bi_\b-
_\bt_\bi_\be_\bs, IEEE --
http://pubs.opengroup.org/onlinepubs/9699919799/
http://tiswww.case.edu/~chet/bash/POSIX -- a description of posix mode
_\b~_\b/_\b._\bb_\ba_\bs_\bh_\br_\bc
The individual per-interactive-shell startup file
_\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bl_\bo_\bg_\bo_\bu_\bt
- The individual login shell cleanup file, executed when a login
+ The individual login shell cleanup file, executed when a login
shell exits
_\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bh_\bi_\bs_\bt_\bo_\br_\by
- The default value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE, the file in which bash saves the
+ The default value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE, the file in which bash saves the
command history
_\b~_\b/_\b._\bi_\bn_\bp_\bu_\bt_\br_\bc
Individual _\br_\be_\ba_\bd_\bl_\bi_\bn_\be initialization file
Once you have determined that a bug actually exists, use the _\bb_\ba_\bs_\bh_\bb_\bu_\bg
command to submit a bug report. If you have a fix, you are encouraged
- to mail that as well! Suggestions and `philosophical' bug reports may
- be mailed to _\bb_\bu_\bg_\b-_\bb_\ba_\bs_\bh_\b@_\bg_\bn_\bu_\b._\bo_\br_\bg or posted to the Usenet newsgroup
+ to mail that as well! You may send suggestions and "philosophical" bug
+ reports to _\bb_\bu_\bg_\b-_\bb_\ba_\bs_\bh_\b@_\bg_\bn_\bu_\b._\bo_\br_\bg or post them to the Usenet newsgroup
g\bgn\bnu\bu.\b.b\bba\bas\bsh\bh.\b.b\bbu\bug\bg.
ALL bug reports should include:
The hardware and operating system
The compiler used to compile
A description of the bug behaviour
- A short script or `recipe' which exercises the bug
+ A short script or "recipe" which exercises the bug
- _\bb_\ba_\bs_\bh_\bb_\bu_\bg inserts the first three items automatically into the template
+ _\bb_\ba_\bs_\bh_\bb_\bu_\bg inserts the first three items automatically into the template
it provides for filing a bug report.
Comments and bug reports concerning this manual page should be directed
Shell builtin commands and functions are not stoppable/restartable.
- Compound commands and command sequences of the form `a ; b ; c' are not
+ Compound commands and command sequences of the form "a ; b ; c" are not
handled gracefully when process suspension is attempted. When a
process is stopped, the shell immediately executes the next command in
the sequence. It suffices to place the sequence of commands between
parentheses to force it into a subshell, which may be stopped as a
- unit.
+ unit, or to start the command in the background and immediately bring
+ it into the foreground.
Array variables may not (yet) be exported.
There may be only one active coprocess at a time.
-
-
-GNU Bash 5.3 2023 December 14 BASH(1)
+GNU Bash 5.3 2024 February 5 _\bB_\bA_\bS_\bH(1)
.\" Case Western Reserve University
.\" chet.ramey@case.edu
.\"
-.\" Last Change: Fri Feb 2 09:38:21 EST 2024
+.\" Last Change: Mon Feb 5 10:51:21 EST 2024
.\"
.\" bash_builtins, strip all but Built-Ins section
.\" avoid a warning about an undefined register
.\" .if !rzY .nr zY 0
.if \n(zZ=1 .ig zZ
.if \n(zY=1 .ig zY
-.TH BASH 1 "2024 February 2" "GNU Bash 5.3"
+.TH BASH 1 "2024 February 5" "GNU Bash 5.3"
.\"
.\" There's some problem with having a `@'
.\" in a tagged paragraph with the BSD man macros.
.\"
.\" File Name macro. This used to be `.PN', for Path Name,
.\" but Sun doesn't seem to like that very much.
-.\" The \% is to prevent the filename from hyphenation.
+.\" \% at the beginning of the string protects the filename from hyphenation.
.\"
.de FN
\%\fI\|\\$1\|\fP
.\"
.de Q
.ie \n(.g \(lq\\$1\(rq\\$2
-.el \{
+.el \{\
. if t ``\\$1''\\$2
. if n "\\$1"\\$2
.\}
..
+.\" Q but disallowing hyphenation of the string
.de QN
.ie \n(.g \%\(lq\\$1\(rq\\$2
-.el \{
-. if t \%``\%\\$1''\\$2
-. if n \%"\%\\$1"\\$2
+.el \{\
+. if t \%``\\$1''\\$2
+. if n \%"\\$1"\\$2
.\}
..
.SH NAME
.PP
.RS
.EX
-if [ \-n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
+if [ \-n \(dq$BASH_ENV\(dq ]; then . \(dq$BASH_ENV\(dq; fi
.EE
.RE
.PP
The format for a pipeline is:
.RS
.PP
-[\fBtime\fP [\fB\-p\fP]] [ ! ] \fIcommand1\fP [ [\fB|\fP\(bv\fB|&\fP] \fIcommand2\fP ... ]
+[\fBtime\fP [\fB\-p\fP]] [ ! ] \fIcommand1\fP [ [\fB|\fP\(bv\fB|&\fP] \fIcommand2\fP .\|.\|.\& ]
.RE
.PP
The standard output of
terminates.
The \fB\-p\fP option changes the output format to that specified by POSIX.
When the shell is in \fIposix mode\fP, it does not recognize
-\fBtime\fP as a reserved word if the next token begins with a `-'.
+\fBtime\fP as a reserved word if the next token begins with a
+.Q \- .
The
.SM
.B TIMEFORMAT
the entire conditional expression.
.RE
.TP
-\fBfor\fP \fIname\fP [ [ \fBin\fP [ \fIword ...\fP ] ] ; ] \fBdo\fP \fIlist\fP ; \fBdone\fP
+\fBfor\fP \fIname\fP [ [ \fBin\fP [ \fIword .\|.\|.\&\fP ] ] ; ] \fBdo\fP \fIlist\fP ; \fBdone\fP
The list of words following \fBin\fP is expanded, generating a list
of items.
The variable \fIname\fP is set to each element of this list
or zero if no commands were executed.
.TP
\fBcase\fP \fIword\fP \fBin\fP [ [(] \fIpattern\fP [ \fB|\fP \fIpattern\fP ] \
-... ) \fIlist\fP ;; ] ... \fBesac\fP
+.\|.\|.\& ) \fIlist\fP ;; ] .\|.\|.\& \
+\fBesac\fP
A \fBcase\fP command first expands \fIword\fP, and tries to match
it against each \fIpattern\fP in turn, using the matching rules
described under
last command executed in \fIlist\fP.
.TP
\fBif\fP \fIlist\fP; \fBthen\fP \fIlist\fP; \
-[ \fBelif\fP \fIlist\fP; \fBthen\fP \fIlist\fP; ] ... \
+[ \fBelif\fP \fIlist\fP; \fBthen\fP \fIlist\fP; ] .\|.\|.\& \
[ \fBelse\fP \fIlist\fP; ] \fBfi\fP
The
.B if
characters:
.BR $ ,
.BR \` ,
-\^\fB"\fP\^,
+\^\fB\(dq\fP\^,
.BR \e ,
or
.BR <newline> .
.B integer
attribute set, then
.I value
-is evaluated as an arithmetic expression even if the $((...)) expansion is
-not used (see
+is evaluated as an arithmetic expression even if the
+.BR $(( .\|.\|.\& ))
+expansion is not used (see
.B "Arithmetic Expansion"
below).
Word splitting and pathname expansion are not performed.
with the value of each parameter separated by the first character of the
.SM
.B IFS
-special variable. That is, "\fB$*\fP" is equivalent
-to "\fB$1\fP\fIc\fP\fB$2\fP\fIc\fP\fB...\fP", where
+special variable.
+That is,
+.B \(dq$*\(dq
+is equivalent to
+.BR \(dq$1\fIc\fP$2\fIc\fP.\|.\|.\(dq ,
+where
.I c
is the first character of the value of the
.SM
In contexts where word splitting is not performed,
this expands to a single word
with each positional parameter separated by a space.
-When the
-expansion occurs within double quotes, each parameter expands to a
-separate word. That is, "\fB$@\fP" is equivalent to
-"\fB$1\fP"\ "\fB$2\fP"\ ...
+When the expansion occurs within double quotes,
+each parameter expands to a separate word.
+That is,
+.B \&\(dq$@\(dq
+is equivalent to
+.B \&\(dq\&$1\&\(dq\ \(dq$2\(dq\ .\|.\|.
If the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the original
word, and the expansion of the last parameter is joined with the last
part of the original word.
-When there are no positional parameters, "\fB$@\fP" and
+When there are no positional parameters,
+.B \&\(dq$@\(dq
+and
.B $@
expand to nothing (i.e., they are removed).
.TP
.B EMACS
If \fBbash\fP finds this variable in the environment when the shell starts
with value
-.Q "t" ,
+.Q t ,
it assumes that the shell is running in an Emacs shell buffer and disables
line editing.
.TP
.B FIGNORE
is excluded from the list of matched filenames.
A sample value is
-.Q ".o:\(ti" .
+.Q .o:\(ti .
.TP
.B FUNCNEST
If set to a numeric value greater than 0, defines a maximum function
.B HISTIGNORE
A colon-separated list of patterns used to decide which command lines
should be saved on the history list. Each pattern is anchored at the
-beginning of the line and must match the complete line (no implicit
-`\fB*\fP' is appended). Each pattern is tested against the line
+beginning of the line and must match the complete line
+(\fBbash\fP will not implicitly append a
+.Q \fB*\fP ).
+Each pattern is tested against the line
after the checks specified by
.SM
.B HISTCONTROL
are applied.
-In addition to the normal shell pattern matching characters, `\fB&\fP'
-matches the previous history line. `\fB&\fP' may be escaped using a
-backslash; the backslash is removed before attempting a match.
+In addition to the normal shell pattern matching characters,
+.Q \fB&\fP
+matches the previous history line.
+A backslash will escape the
+.Q \fB&\fP ;
+the backslash is removed before attempting a match.
The second and subsequent lines of a multi-line compound command are
not tested, and are added to the history regardless of the value of
.SM
.TP
.B HISTTIMEFORMAT
If this variable is set and not null, its value is used as a format string
-for
+for
.IR strftime (3)
to print the time stamp associated with each history
entry displayed by the \fBhistory\fP builtin.
.B MAILPATH
A colon-separated list of filenames to be checked for mail.
The message to be printed when mail arrives in a particular file
-may be specified by separating the filename from the message with a `?'.
+may be specified by separating the filename from the message with a
+.Q ? .
When used in the text of the message, \fB$_\fP expands to the name of
the current mailfile.
Example:
.RS
.PP
-\fBMAILPATH\fP=\(aq/var/mail/bfox?"You have mail":\(ti/shell\-mail?"$_ has mail!"\(aq
+.EX
+\fBMAILPATH\fP=\(aq/var/mail/bfox?\(dqYou have mail\(dq:\(ti/shell\-mail?\(dq$_ has mail!\(dq\(aq
+.EE
.PP
.B Bash
can be configured to supply
.SM
.B PROMPTING
below) and used as the primary prompt string. The default value is
-.Q "\es\-\ev\e$\ " .
+.Q \es\-\ev\e$\ .
.TP
.B PS2
The value of this parameter is expanded as with
.SM
.B PS1
and used as the secondary prompt string. The default is
-.Q ">\ " .
+.Q >\ .
.TP
.B PS3
The value of this parameter is used as the prompt for the
.B PS4
is replicated multiple times, as necessary, to indicate multiple
levels of indirection.
-The default is
-.Q "+\ " .
+The default is
+.Q +\ .
.TP
.B SHELL
This variable expands to the full pathname to the shell.
.B HISTORY EXPANSION
below). The first character is the \fIhistory expansion\fP character,
the character which signals the start of a history
-expansion, normally `\fB!\fP'.
+expansion, normally
+.Q \fB!\fP .
The second character is the \fIquick substitution\fP
character, which is used as shorthand for re-running the previous
command entered, substituting one string for another in the command,
when it appears as the first character on the line.
-The default is `\fB\(ha\fP'.
-The optional third character is the character
-which indicates that the remainder of the line is a comment when found
-as the first character of a word, normally `\fB#\fP'. The history
-comment character causes history substitution to be skipped for the
-remaining words on the line. It does not necessarily cause the shell
-parser to treat the rest of the line as a comment.
+The default is
+.Q \fB\(ha\fP .
+The optional third character is the character which indicates that
+the remainder of the line is a comment when found as the first character
+of a word, normally
+.Q \fB#\fP .
+The history comment character causes history substitution to be skipped
+for the remaining words on the line.
+It does not necessarily cause the shell parser to treat the rest of the
+line as a comment.
.PD
.SS Arrays
.B Bash
builtins. Each attribute applies to all members of an array.
.PP
Arrays are assigned to using compound assignments of the form
-\fIname\fP=\fB(\fPvalue\fI1\fP ... value\fIn\fP\fB)\fP, where each
+\fIname\fP=\fB(\fPvalue\fI1\fP .\|.\|.\& value\fIn\fP\fB)\fP, where each
\fIvalue\fP may be of the form [\fIsubscript\fP]=\fIstring\fP.
Indexed array assignments do not require anything but \fIstring\fP.
Each \fIvalue\fP in the list is expanded using the shell expansions
may be either assignment statements, for which the subscript is required,
or a list of words that is interpreted as a sequence of alternating keys
and values:
-\fIname\fP=\fB( \fP\fIkey1 value1 key2 value2\fP ...\fB)\fP.
+\fIname\fP=\fB( \fP\fIkey1 value1 key2 value2\fP .\|.\|.\&\fB)\fP.
These are treated identically to
-\fIname\fP=\fB(\fP [\fIkey1\fP]=\fIvalue1\fP [\fIkey2\fP]=\fIvalue2\fP ...\fB)\fP.
+\fIname\fP=\fB(\fP [\fIkey1\fP]=\fIvalue1\fP [\fIkey2\fP]=\fIvalue2\fP
+\&.\|.\|.\&\fB)\fP.
The first word in the list determines how the remaining words
are interpreted; all assignments in a list must be of the same type.
When using key/value pairs, the keys may not be missing or empty;
can increase the number of words of the expansion; other expansions
expand a single word to a single word.
The only exceptions to this are the expansions of
-"\fB$@\fP" and "\fB${\fP\fIname\fP\fB[@]}\fP",
+.B \&\(dq$@\(dq
+and
+.B \&\(dq${\fIname\fP[@]}\(dq\c \" keep leading \& for AT&T troff
+.BR \& , \" .BR + \& + \*" doesn't work with AT&T troff
and, in most cases, \fB$*\fP and \fB${\fP\fIname\fP\fB[*]}\fP
as explained above (see
.SM
.PP
Brace expansions may be nested. The results of each expanded
string are not sorted; left to right order is preserved.
-For example, a\fB{\fPd,c,b\fB}\fPe expands into `ade ace abe'.
+For example, a\fB{\fPd,c,b\fB}\fPe expands into
+.Q "ade ace abe" .
.PP
A sequence expression takes the form
\fB{\fP\fIx\fP\fB..\fP\fIy\fP\fB[..\fP\fIincr\fP\fB]}\fP,
and \fIincr\fP, an optional increment, is an integer.
When integers are supplied, the expression expands to each number between
\fIx\fP and \fIy\fP, inclusive.
-Supplied integers may be prefixed with \fI0\fP to force each term to have the
-same width.
+If the supplied integers are prefixed with \fI0\fP, each term will
+have the same width, zero-padding if necessary.
When either \fIx\fP or \fPy\fP begins with a zero, the shell
attempts to force all generated terms to contain the same number of digits,
zero-padding where necessary.
.B SHELL BUILTIN COMMANDS
below).
.SS Tilde Expansion
-If a word begins with an unquoted tilde character (`\fB\(ti\fP'), all of
+If a word begins with an unquoted tilde character (\c
+.Q \fB\(ti\fP ),
+all of
the characters preceding the first unquoted slash (or all characters,
if there is no unquoted slash) are considered a \fItilde-prefix\fP.
If none of the characters in the tilde-prefix are quoted, the
Otherwise, the tilde-prefix is replaced with the home directory
associated with the specified login name.
.PP
-If the tilde-prefix is a `\(ti+', the value of the shell variable
+If the tilde-prefix is a
+.Q \(ti+ ,
+the value of the shell variable
.SM
.B PWD
replaces the tilde-prefix.
-If the tilde-prefix is a `\(ti\-', the value of the shell variable
+If the tilde-prefix is a
+.Q \(ti\- ,
+the value of the shell variable
.SM
.BR OLDPWD ,
if it is set, is substituted.
If the characters following the tilde in the tilde-prefix consist
of a number \fIN\fP, optionally prefixed
-by a `+' or a `\-', the tilde-prefix is replaced with the corresponding
+by a
+.Q +
+or a
+.Q \- ,
+the tilde-prefix is replaced with the corresponding
element from the directory stack, as it would be displayed by the
.B dirs
builtin invoked with the tilde-prefix as an argument.
If the characters following the tilde in the tilde-prefix consist of a
-number without a leading `+' or `\-', `+' is assumed.
+number without a leading
+.Q +
+or
+.Q \- ,
+.Q +
+is assumed.
.PP
If the login name is invalid, or the tilde expansion fails, the word
is unchanged.
\fBBash\fP does not do this, except for the \fIdeclaration\fP commands listed
above, when in \fIposix mode\fP.
.SS Parameter Expansion
-The `\fB$\fP' character introduces parameter expansion,
+The
+.Q \fB$\fP
+character introduces parameter expansion,
command substitution, or arithmetic expansion. The parameter name
or symbol to be expanded may be enclosed in braces, which
are optional but serve to protect the variable to be expanded from
characters immediately following it which could be
interpreted as part of the name.
.PP
-When braces are used, the matching ending brace is the first `\fB}\fP'
+When braces are used, the matching ending brace is the first
+.Q \fB}\fP
not escaped by a backslash or within a quoted string, and not within an
embedded arithmetic expansion, command substitution, or parameter
expansion.
.IR parameter ,
then the result of the expansion is the expanded value of
.I parameter
-with the shortest matching pattern (the
+with the shortest matching pattern (the
.Q #
case) or the longest matching pattern (the
.Q ##
.IR parameter ,
then the result of the expansion is the expanded value of
.I parameter
-with the shortest matching pattern (the
+with the shortest matching pattern (the
.Q %
case) or the longest matching pattern (the
.Q %%
.B Pattern Matching
below.
In the first form above, only the first match is replaced.
-If there are two slashes separating \fIparameter\fP and \fIpattern\fP
+If there are two slashes separating \fIparameter\fP and \fIpattern\fP
(the second form above), all matches of \fIpattern\fP are
replaced with \fIstring\fP.
If \fIpattern\fP is preceded by \fB#\fP (the third form above),
.TP
.B E
The expansion is a string that is the value of \fIparameter\fP with backslash
-escape sequences expanded as with the \fB$\(aq...\(aq\fP quoting mechanism.
+escape sequences expanded as with the \fB$\(aq\fP.\|.\|.\%\fB\(aq\fP
+quoting mechanism.
.TP
.B P
The expansion is a string that is the result of expanding the value of
word would usually require.
.PP
Any side effects of \fIcommand\fP take effect immediately
-in the current execution environment and persist in the current
+in the current execution environment and persist in the current
environment after the command completes (e.g., the \fBexit\fP builtin
will exit the shell).
.PP
.SM
.B IFS
is unset, word splitting behaves as if it contained the default value
-of
+of
.BR <space><tab><newline> .
.PP
-Explicit null arguments (\^\f3"\^"\fP or \^\f3\(aq\^\(aq\fP\^) are retained
+Explicit null arguments (\^\f3\(dq\^\(dq\fP or
+\^\f3\(aq\^\(aq\fP\^) are retained
and passed to commands as empty strings.
Unquoted implicit null arguments, resulting from the expansion of
parameters that have no values, are removed.
non-null, the null argument is removed.
That is, the word
.Q "\-d\(aq\^\(aq"
-becomes
+becomes
.Q \-d
after word splitting and null argument removal.
.PP
.Q .\&
and
.Q ..\& ,
-the pattern must begin with
+the pattern must begin with
.Q .\&
(for example,
.Q .?\& ),
.B ?
Matches any single character.
.TP
-.B [...]
+.BR [ .\|.\|. ]
Matches any one of the enclosed characters.
A pair of characters separated by a hyphen denotes a
\fIrange expression\fP;
characters
.BR \e ,
.BR \(aq ,
-and \^\f3"\fP\^ that did not result from one of the above
+and \^\f3\(dq\fP\^ that did not result from one of the above
expansions are removed.
.SH REDIRECTION
Before a command is executed, its input and output
replaces the word with the alias value, and reads that value as if it
had been read instead of the word.
The shell doesn't look at any characters following the word before
-attempting alias substitution.
+attempting alias substitution.
.PP
The characters \fB/\fP, \fB$\fP, \fB\`\fP, and \fB=\fP and
any of the shell \fImetacharacters\fP or quoting characters
.B \fIexpr\fP?\fIexpr\fP:\fIexpr\fP
conditional operator
.TP
-.B = *= /= %= += \-= <<= >>= &= \(ha= |=
+.B "= *= /= %= += \-= <<= >>= &= \(ha= |="
assignment
.TP
.B \fIexpr1\fP , \fIexpr2\fP
.B SIGINT
to all processes in that process group.
.PP
-When \fBbash\fP is running without job control enabled and receives
+When \fBbash\fP is running without job control enabled and receives
.SM
.B SIGINT
while waiting for a foreground command, it waits until that foreground
.Q "stty tostop" ,
write to the terminal.
Background processes which attempt to read from (write to when
-.Q "tostop"
+.Q tostop
is in effect) the terminal are sent a
.SM
.B SIGTTIN (SIGTTOU)
an ASCII escape character (033)
.TP
.B \eh
-the hostname up to the first `.'
+the hostname up to the first
+.Q .
.TP
.B \eH
the hostname
is the name of a key spelled out in English. For example:
.PP
.RS
+.EX
+.nf
Control-u: universal\-argument
-.br
Meta-Rubout: backward-kill-word
-.br
-Control-o: "> output"
+Control-o: \(dq> output\(dq
+.fi
+.EE
.RE
.LP
In the above example,
.Q "> output"
into the line).
.PP
-In the second form, \fB"keyseq"\fP:\^\fIfunction\-name\fP or \fImacro\fP,
+In the second form,
+\fB\(dqkeyseq\(dq\fP:\^\fIfunction\-name\fP or \fImacro\fP,
.B keyseq
differs from
.B keyname
are not recognized.
.PP
.RS
-"\eC\-u": universal\-argument
-.br
-"\eC\-x\eC\-r": re\-read\-init\-file
-.br
-"\ee[11\(ti": "Function Key 1"
+.EX
+.nf
+\(dq\eC\-u\(dq: universal\-argument
+\(dq\eC\-x\eC\-r\(dq: re\-read\-init\-file
+\(dq\ee[11\(ti\(dq: \(dqFunction Key 1\(dq
+.fi
+.EE
.RE
.PP
In this example,
.B \e\e
backslash
.TP
-.B \e"
-literal "
+.B \e\(dq
+literal \(dq
.TP
.B \e\(aq
literal \(aq
Unquoted text is assumed to be a function name.
In the macro body, the backslash escapes described above are expanded.
Backslash will quote any other character in the macro text,
-including " and \(aq.
+including \(dq and \(aq.
.PP
.B Bash
allows the current readline key bindings to be displayed or modified
.B Off
(without regard to case).
Unrecognized variable names are ignored.
-When a variable value is read, empty or null values, "on" (case-insensitive),
-and "1" are equivalent to \fBOn\fP. All other values are equivalent to
+When readline reads a variable value, empty or null values,
+.Q "on"
+(case-insensitive), and
+.Q 1
+are equivalent to \fBOn\fP.
+All other values are equivalent to
\fBOff\fP.
The variables and their default values are:
.PP
.PD 0
.TP
-.B active\-region\-start\-color
+.B active\-region\-start\-color
A string variable that controls the text color and background when displaying
the text in the active region (see the description of
\fBenable\-active\-region\fP below).
This variable is reset to the default value whenever the terminal type changes.
The default value is the string that puts the terminal in standout mode,
as obtained from the terminal's terminfo description.
-A sample value might be
-.Q "\ee[01;33m" .
+A sample value might be
+.Q \ee[01;33m .
.TP
-.B active\-region\-end\-color
+.B active\-region\-end\-color
A string variable that
.Q undoes
-the effects of \fBactive\-region\-start\-color\fP
+the effects of \fBactive\-region\-start\-color\fP
and restores
.Q normal
terminal display appearance after displaying text in the active region.
The default value is the string that restores the terminal from standout mode,
as obtained from the terminal's terminfo description.
A sample value might be
-.Q "\ee[0m" .
+.Q \ee[0m .
.TP
.B bell\-style (audible)
Controls what happens when readline wants to ring the terminal bell.
If set to \fBaudible\fP, readline attempts to ring the terminal's bell.
.TP
.B bind\-tty\-special\-chars (On)
-If set to \fBOn\fP (the default), readline attempts to bind the control
-characters that are
-treated specially by the kernel's terminal driver to their
-readline equivalents.
+If set to \fBOn\fP (the default), readline attempts to bind
+the control characters that are treated specially by the kernel's
+terminal driver to their readline equivalents.
These override the default readline bindings described here.
Type
.Q "stty \-a"
colors to indicate their file type.
The color definitions are taken from the value of the \fBLS_COLORS\fP
environment variable.
+.\" Tucking multiple macro calls into a paragraph tag requires some
+.\" finesse. We require `\c`, and while the single-font macros don't
+.\" honor input trap continuation, the font alternation macros do.
.TP
-.B comment\-begin (``#'')
+.BR comment\-begin\ (\c
+.Q \fB#\fP \fB)\fP
The string that is inserted when the readline
.B insert\-comment
command is executed.
escape character (in effect, using escape as the \fImeta prefix\fP).
The default is \fIOn\fP, but readline will set it to \fIOff\fP if the
locale contains eight-bit characters.
-This variable is dependent on the \fBLC_CTYPE\fP locale category, and
+This variable is dependent on the \fBLC_CTYPE\fP locale category, and
may change if the locale is changed.
.TP
.B disable\-completion (Off)
.B enable\-active\-region (On)
The \fIpoint\fP is the current cursor position, and \fImark\fP refers
to a saved cursor position.
-The text between the point and mark is referred to as the \fIregion\fP.
+The text between the point and mark is referred to as the \fIregion\fP.
When this variable is set to \fIOn\fP, readline allows certain commands
-to designate the region as \fIactive\fP.
+to designate the region as \fIactive\fP.
When the region is active, readline highlights the text in the region using
the value of the \fBactive\-region\-start\-color\fP, which defaults to the
string that enables
This variable is dependent on the \fBLC_CTYPE\fP locale category, and
may change if the locale is changed.
.TP
-.B isearch\-terminators (``C\-[C\-J'')
+.BR isearch\-terminators\ (\c
+.Q \fBC\-[C\-J\fP \fB)\fP
The string of characters that should terminate an incremental
search without subsequently executing the character as a command.
If this variable has not been given a value, the characters
\fBmark\-directories\fP).
.TP
.B match\-hidden\-files (On)
-This variable, when set to \fBOn\fP, causes readline to match files whose
-names begin with a `.' (hidden files) when performing filename
-completion.
-If set to \fBOff\fP, the leading `.' must be
-supplied by the user in the filename to be completed.
+This variable, when set to \fBOn\fP, forces readline to match files whose
+names begin with a
+.Q .
+(hidden files) when performing filename completion.
+If set to \fBOff\fP, the user must include the leading
+.Q .
+in the filename to be completed.
.TP
.B menu\-complete\-display\-prefix (Off)
If set to \fBOn\fP, menu completion displays the common prefix of the
sequence.
The default is \fIOff\fP, but readline will set it to \fIOn\fP if the
locale contains eight-bit characters.
-This variable is dependent on the \fBLC_CTYPE\fP locale category, and
+This variable is dependent on the \fBLC_CTYPE\fP locale category, and
may change if the locale is changed.
.TP
.B page\-completions (On)
history lines may be modified and retain individual undo lists across
calls to \fBreadline\fP.
.TP
-.B search\-ignore\-case (Off)
+.B search\-ignore\-case (Off)
If set to \fBOn\fP, readline performs incremental and non-incremental
history list searches in a case\-insensitive fashion.
.TP
compilation features of the C preprocessor which allows key
bindings and variable settings to be performed as the result
of tests. There are four parser directives used.
-.IP \fB$if\fP
+.TP
+.B $if
The
.B $if
construct allows bindings to be made based on the
extends to the end of the line;
unless otherwise noted, no characters are required to isolate it.
.RS
-.IP \fBmode\fP
+.TP
+.B mode
The \fBmode=\fP form of the \fB$if\fP directive is used to test
whether readline is in emacs or vi mode.
This may be used in conjunction
with the \fBset keymap\fP command, for instance, to set bindings in
the \fIemacs\-standard\fP and \fIemacs\-ctlx\fP keymaps only if
readline is starting out in emacs mode.
-.IP \fBterm\fP
+.TP
+.B term
The \fBterm=\fP form may be used to include terminal-specific
key bindings, perhaps to bind the key sequences output by the
terminal's function keys. The word on the right side of the
and
.IR sun\-cmd ,
for instance.
-.IP \fBversion\fP
+.TP
+.B version
The \fBversion\fP test may be used to perform comparisons against
specific readline versions.
The \fBversion\fP expands to the current readline version.
is assumed to be \fB0\fP.
The operator may be separated from the string \fBversion\fP
and from the version number argument by whitespace.
-.IP \fBapplication\fP
-The \fBapplication\fP construct is used to include
-application-specific settings. Each program using the readline
+.TP
+.I application
+The \fIapplication\fP construct is used to include
+application-specific settings.
+Each program using the readline
library sets the \fIapplication name\fP, and an initialization
file can test for a particular value.
This could be used to bind key sequences to functions useful for
key sequence that quotes the current or previous word in \fBbash\fP:
.PP
.RS
+.EX
.nf
\fB$if\fP Bash
# Quote the current or previous word
-"\eC\-xq": "\eeb\e"\eef\e""
+\(dq\eC-xq\(dq: \(dq\eeb\e\(dq\eef\e\(dq\(dq
\fB$endif\fP
.fi
+.EE
.RE
-.IP \fIvariable\fP
+.TP
+.I variable
The \fIvariable\fP construct provides simple equality tests for readline
variables and values.
The permitted comparison operators are \fI=\fP, \fI==\fP, and \fI!=\fP.
Both string and boolean variables may be tested. Boolean variables must be
tested against the values \fIon\fP and \fIoff\fP.
.RE
-.IP \fB$endif\fP
+.TP
+.B $endif
This command, as seen in the previous example, terminates an
\fB$if\fP command.
-.IP \fB$else\fP
+.TP
+.B $else
Commands in this branch of the \fB$if\fP directive are executed if
the test fails.
-.IP \fB$include\fP
+.TP
+.B $include
This directive takes a single filename as an argument and reads commands
and bindings from that file. For example, the following directive
would read \fI/etc/inputrc\fP:
Without an argument, move back to the first entry in the history list.
.TP
.B reverse\-search\-history (C\-r)
-Search backward starting at the current line and moving `up' through
-the history as necessary. This is an incremental search.
+Search backward starting at the current line and moving
+.Q up
+through the history as necessary.
+This is an incremental search.
.TP
.B forward\-search\-history (C\-s)
-Search forward starting at the current line and moving `down' through
-the history as necessary. This is an incremental search.
+Search forward starting at the current line and moving
+.Q down
+through the history as necessary.
+This is an incremental search.
.TP
.B non\-incremental\-reverse\-search\-history (M\-p)
Search backward through the history starting at the current line
.B HISTORY EXPANSION
below for a description of history expansion.
.TP
-.B history\-expand\-line (M\-^)
+.B history\-expand\-line (M\-\(ha)
Perform history expansion on the current line.
See
.SM
.B tab\-insert (C\-v TAB)
Insert a tab character.
.TP
-.B self\-insert (a,\ b,\ A,\ 1,\ !,\ ...)
+.B "self\-insert (a, b, A, 1, !, \fR.\|.\|.\fP)"
Insert the character typed.
.TP
.B transpose\-chars (C\-t)
.SS Numeric Arguments
.PD 0
.TP
-.B digit\-argument (M\-0, M\-1, ..., M\-\-)
+.B digit\-argument (M\-0, M\-1, \fR.\|.\|.\fP, M\-\-)
Add this digit to the argument already accumulating, or start a new
argument. M\-\- starts a negative argument.
.TP
ring the terminal's bell (subject to the setting of
.BR bell\-style ).
.TP
-.B do\-lowercase\-version (M\-A, M\-B, M\-\fIx\fP, ...)
+.B do\-lowercase\-version (M\-A, M\-B, M\-\fIx\fP, \fR.\|.\|.\fP)
If the metafied character \fIx\fP is uppercase, run the command
that is bound to the corresponding metafied lowercase character.
The behavior is undefined if \fIx\fP is already lowercase.
.nf
_completion_loader()
{
- . "/etc/bash_completion.d/$1.sh" \c
+ . \(dq/etc/bash_completion.d/$1.sh\(dq \c
.if \n(LL<80n \{\
\e
.br
.IR n .
.TP
.B !!
-Refer to the previous command. This is a synonym for `!\-1'.
+Refer to the previous command. This is a synonym for
+.Q !\-1 .
.TP
.B !\fIstring\fR
Refer to the most recent command preceding the current position in the
zeroth word if there is only one word in the line.
.TP
.B %
-The first word matched by the most recent `?\fIstring\fR?' search,
+The first word matched by the most recent
+.Q ?\fIstring\fR?'
+search,
if the search string begins with a character that is part of a word.
.TP
.I x\fB\-\fPy
-A range of words; `\-\fIy\fR' abbreviates `0\-\fIy\fR'.
+A range of words;
+.Q \-\fIy\fR
+abbreviates
+.Q 0\-\fIy\fR .
.TP
.B *
-All of the words but the zeroth. This is a synonym
-for `\fI1\-$\fP'. It is not an error to use
+All of the words but the zeroth.
+This is a synonym for
+.Q \fI1\-$\fP .
+It is not an error to use
.B *
if there is just one
word in the event; the empty string is returned in that case.
previous command is used as the event.
.SS Modifiers
After the optional word designator, there may appear a sequence of
-one or more of the following modifiers, each preceded by a `:'.
+one or more of the following modifiers, each preceded by a
+.Q : .
These modify, or edit, the word or words selected from the history event.
.PP
.PD 0
Repeat the previous substitution.
.TP
.B g
-Cause changes to be applied over the entire event line. This is
-used in conjunction with `\fB:s\fP' (e.g., `\fB:gs/\fIold\fP/\fInew\fP/\fR')
-or `\fB:&\fP'. If used with
-`\fB:s\fP', any delimiter can be used
-in place of /, and the final delimiter is optional
+Cause changes to be applied over the entire event line.
+This is used in conjunction with
+.Q \fB:s\fP
+(e.g.,
+.Q \fB:gs/\fIold\fP/\fInew\fP/\fR )
+or
+.Q \fB:&\fP .
+If used with
+.Q \fB:s\fP ,
+any delimiter can be used in place of /,
+and the final delimiter is optional
if it is the last character of the event line.
An \fBa\fP may be used as a synonym for \fBg\fP.
.TP
.B G
-Apply the following `\fBs\fP' or `\fB&\fP' modifier once to each word
-in the event line.
+Apply the following
+.Q \fBs\fP
+or
+.Q \fB&\fP
+modifier once to each word in the event line.
.PD
.SH "SHELL BUILTIN COMMANDS"
.\" start of bash_builtins
redirections.
The return status is zero.
.TP
-\fB .\| \fP \fIfilename\fP [\fIarguments\fP]
+\fB\&.\| \fP \fIfilename\fP [\fIarguments\fP]
.PD 0
.TP
\fBsource\fP \fIfilename\fP [\fIarguments\fP]
.I filename
is not found or cannot be read.
.TP
-\fBalias\fP [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
+\fBalias\fP [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] .\|.\|.]
\fBAlias\fP with no arguments or with the
.B \-p
option prints the list of aliases in the form
\fBAlias\fP returns true unless a \fIname\fP is given for which
no alias has been defined.
.TP
-\fBbg\fP [\fIjobspec\fP ...]
+\fBbg\fP [\fIjobspec\fP .\|.\|.]
Resume each suspended job \fIjobspec\fP in the background, as if it
had been started with
.BR & .
initialization file such as
.IR .inputrc ,
but each binding or command must be passed as a separate argument;
-e.g., '"\eC\-x\eC\-r": re\-read\-init\-file'.
+e.g., \(aq\(dq\eC\-x\eC\-r\(dq: re\-read\-init\-file\(aq.
In the following descriptions, output available to be re-read is formatted
as commands that would appear in a
.B readline
.B READLINE_MARK
variables to the current location of the insertion point and the saved
insertion point (the mark), respectively.
-The shell assigns any numeric argument the user supplied to the
+The shell assigns any numeric argument the user supplied to the
.SM
.B READLINE_ARGUMENT
variable.
The return value is true if the directory was successfully changed;
false otherwise.
.TP
-\fBcommand\fP [\fB\-pVv\fP] \fIcommand\fP [\fIarg\fP ...]
+\fBcommand\fP [\fB\-pVv\fP] \fIcommand\fP [\fIarg\fP .\|.\|.]
Run
.I command
with
.br
[\fB\-G\fP \fIglobpat\fP] [\fB\-W\fP \fIwordlist\fP] [\fB\-F\fP \fIfunction\fP] [\fB\-C\fP \fIcommand\fP]
.br
-[\fB\-X\fP \fIfilterpat\fP] [\fB\-P\fP \fIprefix\fP] [\fB\-S\fP \fIsuffix\fP] \fIname\fP [\fIname ...\fP]
+[\fB\-X\fP \fIfilterpat\fP] [\fB\-P\fP \fIprefix\fP] \
+[\fB\-S\fP \fIsuffix\fP] \fIname\fP [\fIname\fP .\|.\|.]
.PD 0
.TP
-\fBcomplete\fP \fB\-pr\fP [\fB\-DEI\fP] [\fIname\fP ...]
+\fBcomplete\fP \fB\-pr\fP [\fB\-DEI\fP] [\fIname\fP .\|.\|.]
.PD
Specify how arguments to each \fIname\fP should be completed.
If the \fB\-p\fP option is supplied, or if no options or \fIname\fPs
loop).
The return value is 0 unless \fIn\fP is not greater than or equal to 1.
.TP
-\fBdeclare\fP [\fB\-aAfFgiIlnrtux\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
+\fBdeclare\fP [\fB\-aAfFgiIlnrtux\fP] [\fB\-p\fP] \
+[\fIname\fP[=\fIvalue\fP] .\|.\|.]
.PD 0
.TP
-\fBtypeset\fP [\fB\-aAfFgiIlnrtux\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
+\fBtypeset\fP [\fB\-aAfFgiIlnrtux\fP] [\fB\-p\fP] \
+[\fIname\fP[=\fIvalue\fP] .\|.\|.]
.PD
Declare variables and/or give them attributes.
If no \fIname\fPs are given then display the values of variables.
The
.B \-I
option causes local variables to inherit the attributes
-(except the \fInameref\fP attribute)
+(except the \fInameref\fP attribute)
and value of any existing variable with the same
\fIname\fP at a surrounding scope.
If there is no existing variable, the local variable is initially unset.
Mark \fIname\fPs for export to subsequent commands via the environment.
.PD
.PP
-Using `+' instead of `\-'
+Using
+.Q +
+instead of
+.Q \-
turns off the attribute instead,
with the exceptions that \fB+a\fP and \fB+A\fP
may not be used to destroy array variables and \fB+r\fP will not
of the directory stack.
.RE
.TP
-\fBdisown\fP [\fB\-ar\fP] [\fB\-h\fP] [\fIjobspec\fP ... | \fIpid\fP ... ]
+\fBdisown\fP [\fB\-ar\fP] [\fB\-h\fP] \
+[\fIjobspec\fP .\|.\|. | \fIpid\fP .\|.\|. ]
Without options, remove each
.I jobspec
from the table of active jobs.
.I jobspec
does not specify a valid job.
.TP
-\fBecho\fP [\fB\-neE\fP] [\fIarg\fP ...]
+\fBecho\fP [\fB\-neE\fP] [\fIarg\fP .\|.\|.]
Output the \fIarg\fPs, separated by spaces, followed by a newline.
The return status is 0 unless a write error occurs.
If \fB\-n\fP is specified, the trailing newline is
.PD
.RE
.TP
-\fBenable\fP [\fB\-a\fP] [\fB\-dnps\fP] [\fB\-f\fP \fIfilename\fP] [\fIname\fP ...]
+\fBenable\fP [\fB\-a\fP] [\fB\-dnps\fP] [\fB\-f\fP \fIfilename\fP] \
+[\fIname\fP .\|.\|.]
Enable and disable builtin shell commands.
Disabling a builtin allows a disk command which has the same name
as a shell builtin to be executed without specifying a full pathname,
is not a shell builtin or there is an error loading a new builtin
from a shared object.
.TP
-\fBeval\fP [\fIarg\fP ...]
+\fBeval\fP [\fIarg\fP .\|.\|.]
The \fIarg\fPs are read and concatenated together into a single
command. This command is then read and executed by the shell, and
its exit status is returned as the value of
.B EXIT
is executed before the shell terminates.
.TP
-\fBexport\fP [\fB\-fn\fP\^] [\fIname\fP[=\fIword\fP]] ...
+\fBexport\fP [\fB\-fn\fP\^] [\fIname\fP[=\fIword\fP]] .\|.\|.
.PD 0
.TP
.B export \-p
of \fIpat\fP is replaced by \fIrep\fP.
\fICommand\fP is interpreted the same as \fIfirst\fP above.
A useful alias to use with this is
-.Q "r=""fc \-s""" ,
+.Q "r=\(dqfc \-s\(dq" ,
so that typing
.Q "r cc"
runs the last command beginning with
.I jobspec
specifies a job that was started without job control.
.TP
-\fBgetopts\fP \fIoptstring\fP \fIname\fP [\fIarg ...\fP]
+\fBgetopts\fP \fIoptstring\fP \fIname\fP [\fIarg\fP .\|.\|.]
.B getopts
is used by shell procedures to parse positional parameters.
.I optstring
.TP
\fBhistory\fP \fB\-anrw\fP [\fIfilename\fP]
.TP
-\fBhistory\fP \fB\-p\fP \fIarg\fP [\fIarg ...\fP]
+\fBhistory\fP \fB\-p\fP \fIarg\fP [\fIarg\fP .\|.\|.]
.TP
-\fBhistory\fP \fB\-s\fP \fIarg\fP [\fIarg ...\fP]
+\fBhistory\fP \fB\-s\fP \fIarg\fP [\fIarg\fP .\|.\|.]
.PD
With no options, display the command
history list with line numbers. Lines listed
history expansion supplied as an argument to \fB\-p\fP fails.
.RE
.TP
-\fBjobs\fP [\fB\-lnprs\fP] [ \fIjobspec\fP ... ]
+\fBjobs\fP [\fB\-lnprs\fP] [ \fIjobspec\fP .\|.\|. ]
.PD 0
.TP
-\fBjobs\fP \fB\-x\fP \fIcommand\fP [ \fIargs\fP ... ]
+\fBjobs\fP \fB\-x\fP \fIcommand\fP [ \fIargs\fP .\|.\|. ]
.PD
The first form lists the active jobs. The options have the following
meanings:
returning its exit status.
.RE
.TP
-\fBkill\fP [\fB\-s\fP \fIsigspec\fP | \fB\-n\fP \fIsignum\fP | \fB\-\fP\fIsigspec\fP] [\fIpid\fP | \fIjobspec\fP] ...
+\fBkill\fP [\fB\-s\fP \fIsigspec\fP | \fB\-n\fP \fIsignum\fP | \fB\-\fP\fIsigspec\fP] \
+[\fIpid\fP | \fIjobspec\fP] .\|.\|.
.PD 0
.TP
\fBkill\fP \fB\-l\fP|\fB\-L\fP [\fIsigspec\fP | \fIexit_status\fP]
returns true if at least one signal was successfully sent, or false
if an error occurs or an invalid option is encountered.
.TP
-\fBlet\fP \fIarg\fP [\fIarg\fP ...]
+\fBlet\fP \fIarg\fP [\fIarg\fP .\|.\|.]
Each
.I arg
is an arithmetic expression to be evaluated (see
.B let
returns 1; 0 is returned otherwise.
.TP
-\fBlocal\fP [\fIoption\fP] [\fIname\fP[=\fIvalue\fP] ... | \- ]
+\fBlocal\fP [\fIoption\fP] [\fIname\fP[=\fIvalue\fP] .\|.\|. | \- ]
For each argument, a local variable named
.I name
is created, and assigned
reading the name of the current directory or an
invalid option is supplied.
.TP
-\fBread\fP [\fB\-Eers\fP] [\fB\-a\fP \fIaname\fP] [\fB\-d\fP \fIdelim\fP] [\fB\-i\fP \fItext\fP] [\fB\-n\fP \fInchars\fP] [\fB\-N\fP \fInchars\fP] [\fB\-p\fP \fIprompt\fP] [\fB\-t\fP \fItimeout\fP] [\fB\-u\fP \fIfd\fP] [\fIname\fP ...]
+\fBread\fP [\fB\-Eers\fP] [\fB\-a\fP \fIaname\fP] \
+[\fB\-d\fP \fIdelim\fP] [\fB\-i\fP \fItext\fP] \
+[\fB\-n\fP \fInchars\fP] [\fB\-N\fP \fInchars\fP] \
+[\fB\-p\fP \fIprompt\fP] [\fB\-t\fP \fItimeout\fP] \
+[\fB\-u\fP \fIfd\fP] [\fIname\fP .\|.\|.]
One line is read from the standard input, or from the file descriptor
\fIfd\fP supplied as an argument to the \fB\-u\fP option,
split into words as described
or an invalid file descriptor is supplied as the argument to \fB\-u\fP.
.RE
.TP
-\fBreadonly\fP [\fB\-aAf\fP] [\fB\-p\fP] [\fIname\fP[=\fIword\fP] ...]
+\fBreadonly\fP [\fB\-aAf\fP] [\fB\-p\fP] [\fIname\fP[=\fIword\fP] .\|.\|.]
.PD
The given
\fInames\fP are marked readonly; the values of these
Any command associated with the \fBRETURN\fP trap is executed
before execution resumes after the function or script.
.TP
-\fBset\fP [\fB\-abefhkmnptuvxBCEHPT\fP] [\fB\-o\fP \fIoption\-name\fP] [\fB\-\-\fP] [\fB\-\fP] [\fIarg\fP ...]
+\fBset\fP [\fB\-abefhkmnptuvxBCEHPT\fP] [\fB\-o\fP \fIoption\-name\fP] \
+[\fB\-\-\fP] [\fB\-\fP] [\fIarg\fP .\|.\|.]
.PD 0
.TP
-\fBset\fP [\fB+abefhkmnptuvxBCEHPT\fP] [\fB+o\fP \fIoption\-name\fP] [\fB\-\-\fP] [\fB\-\fP] [\fIarg\fP ...]
+\fBset\fP [\fB+abefhkmnptuvxBCEHPT\fP] [\fB+o\fP \fIoption\-name\fP] \
+[\fB\-\-\fP] [\fB\-\fP] [\fIarg\fP .\|.\|.]
.TP
\fBset \-o\fP
.TP
as values for the positional parameters and are assigned, in order, to
.BR $1 ,
.BR $2 ,
-.B ...
+\&.\|.\|.,
.BR $\fIn\fP .
Options, if specified, have the following meanings:
.RS
.TP 8
.B \-u
Treat unset variables and parameters other than the special
-parameters "@" and "*",
-or array variables subscripted with "@" or "*",
-as an error when performing
-parameter expansion. If expansion is attempted on an
-unset variable or parameter, the shell prints an error message, and,
+parameters
+.Q @
+and
+.Q * ,
+or array variables subscripted with
+.Q @
+or
+.Q * ,
+as an error when performing parameter expansion.
+If expansion is attempted on an unset variable or parameter,
+the shell prints an error message, and,
if not interactive, exits with a non-zero status.
.TP 8
.B \-v
.RE
.TP
\fBshift\fP [\fIn\fP]
-The positional parameters from \fIn\fP+1 ... are renamed to
+The positional parameters from \fIn\fP+1 .\|.\|.\& are renamed to
.B $1
-.B ....
+.B .\|.\|..
Parameters represented by the numbers \fB$#\fP
down to \fB$#\fP\-\fIn\fP+1 are unset.
.I n
.B $#
or less than zero; otherwise 0.
.TP
-\fBshopt\fP [\fB\-pqsu\fP] [\fB\-o\fP] [\fIoptname\fP ...]
+\fBshopt\fP [\fB\-pqsu\fP] [\fB\-o\fP] [\fIoptname\fP .\|.\|.]
Toggle the values of settings controlling optional shell behavior.
The settings can be either those listed below, or, if the
.B \-o
and while executing builtins that perform array dereferencing.
.TP 8
.B assoc_expand_once
-Deprecated; a synonym for \fBarray_expand_once\fP.
+Deprecated; a synonym for \fBarray_expand_once\fP.
.TP 8
.B autocd
If set, a command name that is the name of a directory is executed as if
\fBPathname Expansion\fP are enabled.
.TP 8
.B extquote
-If set, \fB$\fP\(aq\fIstring\fP\(aq and \fB$\fP"\fIstring\fP" quoting is
+If set, \fB$\fP\(aq\fIstring\fP\(aq and \fB$\fP\(dq\fIstring\fP\(dq quoting is
performed within \fB${\fP\fIparameter\fP\fB}\fP expansions
enclosed in double quotes. This option is enabled by default.
.TP 8
.B noexpand_translation
If set,
.B bash
-encloses the translated results of $"..." quoting in single quotes
-instead of double quotes.
+encloses the translated results of
+.BR $\(dq .\|.\|.\& \(dq
+quoting in single quotes instead of double quotes.
If the string is not translated, this has no effect.
.TP 8
.B nullglob
the evaluation of the conditional expression
.IR expr .
Each operator and operand must be a separate argument.
-Expressions are composed of the primaries described
+Expressions are composed of the primaries described
.ie \n(zZ=1 in \fIbash\fP(1)
.el above
under
using the rules listed above.
.PD
.PP
-If the shell is not in \fIposix mode\fP,
-when used with \fBtest\fP or \fB[\fP, the \fB<\fP and \fB>\fP operators
-sort lexicographically using ASCII ordering.
-When the shell is in \fIposix mode\fP, these operators sort using the
+When the shell is in \fIposix mode\fP, or if the expression is part
+of the \fB[[\fP command,
+the \fB<\fP and \fB>\fP operators sort using the
current locale.
+If the shell is not in \fIposix mode\fP, the \fBtest\fP and \fB[\fP
+commands sort lexicographically using ASCII ordering.
.RE
.TP
.B times
Print the accumulated user and system times for the shell and
for processes run from the shell. The return status is 0.
.TP
-\fBtrap\fP [\fB\-lp\fP] [[\fIaction\fP] \fIsigspec\fP ...]
+\fBtrap\fP [\fB\-lp\fP] [[\fIaction\fP] \fIsigspec\fP .\|.\|.]
The
.I action
is a command that is read and executed when the shell receives
.I action
is executed before every \fIsimple command\fP, \fIfor\fP command,
\fIcase\fP command, \fIselect\fP command, (( arithmetic command,
-[[ conditional command,
+[[ conditional command,
arithmetic \fIfor\fP command, and before the first command executes
in a shell function (see
.SM
\fBtrue\fP
Does nothing, returns a 0 status.
.TP
-\fBtype\fP [\fB\-aftpP\fP] \fIname\fP [\fIname\fP ...]
+\fBtype\fP [\fB\-aftpP\fP] \fIname\fP [\fIname\fP .\|.\|.]
With no options,
indicate how each
.I name
can be supplied to restrict the output to executable files.
\fBtype\fP does not consult the table of hashed commands
when using
-.B \-a
+.B \-a
with
.BR \-p ,
and only performs a
The maximum size of a process's data segment
.TP
.B \-e
-The maximum scheduling priority (
+The maximum scheduling priority (\c
.Q nice ).
.TP
.B \-f
The return status is 0 if the mode was successfully changed or if
no \fImode\fP argument was supplied, and false otherwise.
.TP
-\fBunalias\fP [\-\fBa\fP] [\fIname\fP ...]
+\fBunalias\fP [\-\fBa\fP] [\fIname\fP .\|.\|.]
Remove each \fIname\fP from the list of defined aliases. If
.B \-a
is supplied, all alias definitions are removed. The return
.I name
is not a defined alias.
.TP
-\fBunset\fP [\-\fBfv\fP] [\-\fBn\fP] [\fIname\fP ...]
+\fBunset\fP [\-\fBfv\fP] [\-\fBn\fP] [\fIname\fP .\|.\|.]
For each
.IR name ,
remove the corresponding variable or function.
.I name
is readonly or may not be unset.
.TP
-\fBwait\fP [\fB\-fn\fP] [\fP\-p\fP \fIvarname\fP] [\fIid ...\fP]
+\fBwait\fP [\fB\-fn\fP] [\fP\-p\fP \fIvarname\fP] [\fIid\fP .\|.\|.]
Wait for each specified child process and return its termination status.
Each
.I id
process or job waited for.
.SH "SHELL COMPATIBILITY MODE"
Bash-4.0 introduced the concept of a \fIshell compatibility level\fP,
-specified as a set of options to the shopt builtin (
+specified as a set of options to the shopt builtin (\c
.BR compat31 ,
.BR compat32 ,
.BR compat40 ,
This section does not mention behavior that is standard for a particular
version (e.g., setting \fBcompat32\fP means that quoting the rhs of the regexp
matching operator quotes special regexp characters in the word, which is
-default behavior in bash-3.2 and subsequent versions).
+default behavior in bash-3.2 and subsequent versions).
.PP
If a user enables, say, \fBcompat32\fP, it may affect the behavior of other
compatibility levels up to and including the current compatibility level.
.PP
Bash-5.0 was the final version for which there will be an individual shopt
option for the previous version. Users should control the compatibility
-level with
+level with
.SM
.BR BASH_COMPAT .
.PP
and \fB*\fP differently depending on whether the array is indexed or
associative, and differently than in previous versions.
.IP \(bu
-arithmetic commands ( ((...)) ) and the expressions in an arithmetic for
+arithmetic commands (
+.BR (( .\|.\|.\& ))
+) and the expressions in an arithmetic for
statement can be expanded more than once
.IP \(bu
expressions used as arguments to arithmetic operators in the \fB[[\fP
the expressions in substring parameter brace expansion can be
expanded more than once
.IP \(bu
-the expressions in the $(( ... )) word expansion can be expanded
-more than once
+the expressions in the
+.BR $(( .\|.\|.\& ))
+word expansion can be expanded more than once
.IP \(bu
arithmetic expressions used as indexed array subscripts can be
expanded more than once
.I bashbug
command to submit a bug report.
If you have a fix, you are encouraged to mail that as well!
-Suggestions and `philosophical' bug reports may be mailed
-to \fIbug-bash@gnu.org\fP or posted to the Usenet
+You may send suggestions and
+.Q philosophical
+bug reports to \fIbug-bash@gnu.org\fP or post them to the Usenet
newsgroup
.BR gnu.bash.bug .
.PP
.TP
A description of the bug behaviour
.TP
-A short script or `recipe' which exercises the bug
+A short script or \c
+.Q recipe " \c"
+which exercises the bug
.PD
.PP
.I bashbug
.PP
Shell builtin commands and functions are not stoppable/restartable.
.PP
-Compound commands and command sequences of the form `a ; b ; c'
+Compound commands and command sequences of the form
+.Q "a ; b ; c"
are not handled gracefully when process suspension is attempted.
When a process is stopped, the shell immediately executes the next
command in the sequence.
-It suffices to place the sequence of commands between
-parentheses to force it into a subshell, which may be stopped as
-a unit.
+It suffices to place the sequence of commands between parentheses to
+force it into a subshell, which may be stopped as a unit,
+or to start the command in the background and immediately
+bring it into the foreground.
.PP
Array variables may not (yet) be exported.
.PP
</HEAD>
<BODY><TABLE WIDTH=100%>
<TR>
-<TH ALIGN=LEFT width=33%>BASH(1)<TH ALIGN=CENTER width=33%>2023 December 14<TH ALIGN=RIGHT width=33%>BASH(1)
+<TH ALIGN=LEFT width=33%>BASH(1)<TH ALIGN=CENTER width=33%>2024 February 5<TH ALIGN=RIGHT width=33%>BASH(1)
</TR>
</TABLE>
<BR><A HREF="#index">Index</A>
+
+
+
+
+
+
+
+
behaves as if the following command were executed:
<P>
+
<DL COMPACT><DT><DD>
-<TT>if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi</TT>
+
+if [ -n dq$BASH_ENVdq ]; then . dq$BASH_ENVdq; fi
</DL>
<P>
+
but the value of the
<FONT SIZE=-1><B>PATH</B>
terminates.
The <B>-p</B> option changes the output format to that specified by POSIX.
When the shell is in <I>posix mode</I>, it does not recognize
-<B>time</B> as a reserved word if the next token begins with a `-'.
+<B>time</B> as a reserved word if the next token begins with a
+
The
<FONT SIZE=-1><B>TIMEFORMAT</B>
but double quote characters in <I>expression</I> are not treated specially
and are removed.
<DT><B>[[</B> <I>expression</I> <B>]]</B><DD>
+
Return a status of 0 or 1 depending on the evaluation of
the conditional expression <I>expression</I>.
Expressions are composed of the primaries described below under
(the expansions that would occur if the words were enclosed in double quotes).
Conditional operators such as <B>-f</B> must be unquoted to be recognized
as primaries.
-<P>
-
-
+<DT><DD>
When used with <B>[[</B>, the <B><</B> and <B>></B> operators sort
lexicographically using the current locale.
-<P>
-
-
+<DT><DD>
When the <B>==</B> and <B>!=</B> operators are used, the string to the
right of the operator is considered a pattern and matched according
to the rules described below under <B>Pattern Matching</B>,
(<B>!=</B>) the pattern, and 1 otherwise.
Any part of the pattern may be quoted to force the quoted portion
to be matched as a string.
-<P>
-
-
+<DT><DD>
An additional binary operator, <B>=ti</B>, is available, with the same
precedence as <B>==</B> and <B>!=</B>.
When it is used, the string to the right of the operator is considered
a POSIX extended regular expression and matched accordingly
(using the POSIX <I>regcomp</I> and <I>regexec</I> interfaces
-usually described in <I>regex</I>(3)).
+usually described in
+<I>regex</I>(3)).
+
The return value is 0 if the string matches
the pattern, and 1 otherwise.
If the regular expression is syntactically incorrect, the conditional
Treat bracket expressions in regular expressions carefully,
since normal quoting and pattern characters lose their meanings
between brackets.
-<P>
-
-
+<DT><DD>
The pattern will match if it matches any part of the string.
Anchor the pattern using the <B>ha</B> and <B>$</B> regular expression
operators to force it to match the entire string.
</FONT>
in the global scope; declaring it as a local variable will lead to
unexpected results.
-<P>
-
-
+<DT><DD>
Expressions may be combined using the following operators, listed
in decreasing order of precedence:
-<P>
-
-
+<DT><DD>
<DL COMPACT><DT><DD>
<DL COMPACT>
or zero if no commands were executed.
<DT><B>case</B> <I>word</I> <B>in</B> [ [(] <I>pattern</I> [ <B>|</B> <I>pattern</I> ]
-<DD>
+.. ) <I>list</I> ;; ] ... <B>esac</B><DD>
A <B>case</B> command first expands <I>word</I>, and tries to match
it against each <I>pattern</I> in turn, using the matching rules
described under
<B>`</B>,
-<B>"</B>,
+<B>dq</B>,
<B>\</B>,
or
attribute set, then
<I>value</I>
-is evaluated as an arithmetic expression even if the $((...)) expansion is
-not used (see
+is evaluated as an arithmetic expression even if the
+<B>$((</B>...<B>))</B>
+
+expansion is not used (see
<B>Arithmetic Expansion</B>
below).
For instance, if a variable name is passed to a shell function as its first
argument, running
<P>
+
<DL COMPACT><DT><DD>
-<TT>declare -n ref=$1</TT>
+
+declare -n ref=$1
</DL>
<P>
+
inside the function creates a nameref variable <B>ref</B> whose value is
the variable name passed as the first argument.
References and assignments to <B>ref</B>, and changes to its attributes,
<FONT SIZE=-1><B>IFS</B>
</FONT>
-special variable. That is, "<B>$*</B>" is equivalent
-to "<B>$1</B><I>c</I><B>$2</B><I>c</I><B>...</B>", where
+special variable.
+That is,
+<B>dq$*dq</B>
+
+is equivalent to
+<B>dq$1</B><I>c</I>$2<I>c</I>...dq,
+
+where
<I>c</I>
is the first character of the value of the
In contexts where word splitting is not performed,
this expands to a single word
with each positional parameter separated by a space.
-When the
-expansion occurs within double quotes, each parameter expands to a
-separate word. That is, "<B>$@</B>" is equivalent to
-"<B>$1</B>" "<B>$2</B>" ...
+When the expansion occurs within double quotes,
+each parameter expands to a separate word.
+That is,
+<B>dq$@dq</B>
+
+is equivalent to
+<B>dq$1dq dq$2dq ...</B>
+
If the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the original
word, and the expansion of the last parameter is joined with the last
part of the original word.
-When there are no positional parameters, "<B>$@</B>" and
+When there are no positional parameters,
+<B>dq$@dq</B>
+
+and
<B>$@</B>
expand to nothing (i.e., they are removed).
<B>bash</B>.
The values assigned to the array members are as follows:
+</DL>
<P>
+
<DL COMPACT><DT><DD>
<DL COMPACT>
<DT><B>BASH_VERSINFO[</B>0]
<DT><B>BASH_VERSINFO[</B>4]
<DD>
-The release status (e.g., <I>beta1</I>).
+The release status (e.g., <I>beta</I>).
<DT><B>BASH_VERSINFO[</B>5]
<DD>
</FONT>
</DL></DL>
+<DL COMPACT>
<DT><B>BASH_VERSION</B>
<DD>
<DD>
Each time this parameter is referenced, it expands to the number of seconds
-since the Unix Epoch (see <I>time</I>(3)) as a floating point value
-with micro-second granularity.
+since the Unix Epoch (see
+<I>time</I>(3))
+
+as a floating point value with micro-second granularity.
Assignments to
<FONT SIZE=-1><B>EPOCHREALTIME</B>
<DD>
Each time this parameter is referenced, it expands to the number of seconds
-since the Unix Epoch (see <I>time</I>(3)).
+since the Unix Epoch (see
+<I>time</I>(3)).
+
Assignments to
<FONT SIZE=-1><B>EPOCHSECONDS</B>
<DT><B>FUNCNAME</B>
<DD>
+
An array variable containing the names of all shell functions
currently in the execution call stack.
The element with index 0 is the name of any currently-executing
shell function.
The bottom-most element (the one with the highest index) is
-<TT>"main"</TT>.
This variable exists only when a shell function is executing.
Assignments to
</FONT>
is unset, it loses its special properties, even if it is
subsequently reset.
-<P>
-
-
+<DT><DD>
This variable can be used with <B>BASH_LINENO</B> and <B>BASH_SOURCE</B>.
Each element of <B>FUNCNAME</B> has corresponding elements in
<B>BASH_LINENO</B> and <B>BASH_SOURCE</B> to describe the call stack.
<B>${BASH_LINENO[</B><I>$i</I><B>]}</B>.
The <B>caller</B> builtin displays the current call stack using this
information.
+
<DT><B>GROUPS</B>
<DD>
<DD>
Any numeric argument given to a readline command that was defined using
-<TT>bind -x</TT>
(see
<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
<B>readline</B>
line buffer, for use with
-<TT>bind -x</TT>
(see
<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
<B>readline</B>
line buffer, for use with
-<TT>bind -x</TT>
(see
<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
<B>readline</B>
line buffer, for use with
-<TT>bind -x</TT>
(see
<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
<DD>
This variable expands to a 32-bit pseudo-random number each time it is
referenced. The random number generator is not linear on systems that
-support <TT>/dev/urandom</TT> or <I>arc4random</I>, so each returned number
+support
+
+<I>/dev/urandom</I>
+
+or
+<I>arc4random</I>(3),
+
+so each returned number
has no relationship to the numbers preceding it.
The random number generator cannot be seeded, so assignments to this
variable have no effect.
If <B>BASH_COMPAT</B> is set to a value that is not one of the valid
compatibility levels, the shell prints an error message and sets the
compatibility level to the default for the current version.
-The valid values correspond to the compatibility levels
+A subset of the valid values correspond to the compatibility levels
described below under
<FONT SIZE=-1><B>SHELL COMPATIBILITY MODE</B>.
<DD>
If set to an integer corresponding to a valid file descriptor, <B>bash</B>
will write the trace output generated when
-<TT>set -x</TT>
is enabled to that file descriptor.
The file descriptor is closed when
command.
A sample value is
-<TT>".:ti:/usr"</TT>.
<DT><B>CHILD_MAX</B>
<DD>
If <B>bash</B> finds this variable in the environment when the shell starts
with value
-<TT>t</TT>,
it assumes that the shell is running in an Emacs shell buffer and disables
line editing.
</FONT>
is excluded from the list of matched filenames.
A sample value is
-<TT>".o:ti"</TT>.
<DT><B>FUNCNEST</B>
<DD>
A colon-separated list of patterns used to decide which command lines
should be saved on the history list. Each pattern is anchored at the
-beginning of the line and must match the complete line (no implicit
-`<B>*</B>' is appended). Each pattern is tested against the line
+beginning of the line and must match the complete line
+(<B>bash</B> will not implicitly append a
+
+Each pattern is tested against the line
after the checks specified by
<FONT SIZE=-1><B>HISTCONTROL</B>
</FONT>
are applied.
-In addition to the normal shell pattern matching characters, `<B>&</B>'
-matches the previous history line. `<B>&</B>' may be escaped using a
-backslash; the backslash is removed before attempting a match.
+In addition to the normal shell pattern matching characters,
+
+matches the previous history line.
+A backslash will escape the
+
+the backslash is removed before attempting a match.
The second and subsequent lines of a multi-line compound command are
not tested, and are added to the history regardless of the value of
<FONT SIZE=-1><B>HISTIGNORE</B>.
<DD>
If this variable is set and not null, its value is used as a format string
-for <I>strftime</I>(3) to print the time stamp associated with each history
+for
+<I>strftime</I>(3)
+
+to print the time stamp associated with each history
entry displayed by the <B>history</B> builtin.
If this variable is set, time stamps are written to the history file so
they may be preserved across shell sessions.
<B>read</B>
builtin command. The default value is
-``<space><tab><newline>''.
+
<DT><B>IGNOREEOF</B>
<DD>
<DD>
A colon-separated list of filenames to be checked for mail.
The message to be printed when mail arrives in a particular file
-may be specified by separating the filename from the message with a `?'.
+may be specified by separating the filename from the message with a
+
When used in the text of the message, <B>$_</B> expands to the name of
the current mailfile.
Example:
<DL COMPACT><DT><DD>
<P>
-<B>MAILPATH</B>=aq/var/mail/bfox?"You have mail":ti/shell-mail?"$_ has mail!"aq
+
+<B>MAILPATH</B>=aq/var/mail/bfox?dqYou have maildq:ti/shell-mail?dq$_ has mail!dqaq
+
<P>
<B>Bash</B>
A common value is
-<TT>/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin</TT>.
<DT><B>POSIXLY_CORRECT</B>
invocation option had been supplied. If it is set while the shell is
running, <B>bash</B> enables <I>posix mode</I>, as if the command
-<TT>set -o posix</TT>
had been executed.
When the shell enters <I>posix mode</I>, it sets this variable if it was
</FONT>
below) and used as the primary prompt string. The default value is
-``<B>\s-\v\$ </B>''.
+
<DT><B>PS2</B>
<DD>
</FONT>
and used as the secondary prompt string. The default is
-``<B>> </B>''.
+
<DT><B>PS3</B>
<DD>
and the value is printed before each command
<B>bash</B>
-displays during an execution trace. The first character of
-the expanded value of
+displays during an execution trace.
+The first character of the expanded value of
<FONT SIZE=-1><B>PS4</B>
</FONT>
is replicated multiple times, as necessary, to indicate multiple
-levels of indirection. The default is ``<B>+ </B>''.
+levels of indirection.
+The default is
+
<DT><B>SHELL</B>
<DD>
The <B>%</B> character introduces an escape sequence that is
expanded to a time value or other information.
The escape sequences and their meanings are as follows; the
-braces denote optional portions.
+brackets denote optional portions.
+</DL>
<P>
+
<DL COMPACT><DT><DD>
<DL COMPACT>
</DL></DL>
+<DL COMPACT>
<DT><DD>
The optional <I>p</I> is a digit specifying the <I>precision</I>,
the number of fractional digits after a decimal point.
</FONT>
below). The first character is the <I>history expansion</I> character,
the character which signals the start of a history
-expansion, normally `<B>!</B>'.
+expansion, normally
+
The second character is the <I>quick substitution</I>
character, which is used as shorthand for re-running the previous
command entered, substituting one string for another in the command,
when it appears as the first character on the line.
-The default is `<B>ha</B>'.
-The optional third character is the character
-which indicates that the remainder of the line is a comment when found
-as the first character of a word, normally `<B>#</B>'. The history
-comment character causes history substitution to be skipped for the
-remaining words on the line. It does not necessarily cause the shell
-parser to treat the rest of the line as a comment.
+The default is
+
+The optional third character is the character which indicates that
+the remainder of the line is a comment when found as the first character
+of a word, normally
+
+The history comment character causes history substitution to be skipped
+for the remaining words on the line.
+It does not necessarily cause the shell parser to treat the rest of the
+line as a comment.
</DL>
<A NAME="lbAX"> </A>
and values:
<I>name</I>=<B>( </B><I>key1 value1 key2 value2</I> ...<B>)</B>.
These are treated identically to
-<I>name</I>=<B>(</B> [<I>key1</I>]=<I>value1</I> [<I>key2</I>]=<I>value2</I> ...<B>)</B>.
+<I>name</I>=<B>(</B> [<I>key1</I>]=<I>value1</I> [<I>key2</I>]=<I>value2</I>
+...<B>)</B>.
The first word in the list determines how the remaining words
are interpreted; all assignments in a list must be of the same type.
When using key/value pairs, the keys may not be missing or empty;
<H3>EXPANSION</H3>
Expansion is performed on the command line after it has been split into
-words. There are seven kinds of expansion performed:
+words. The shell performs these expansions:
<I>brace expansion</I>,
<I>tilde expansion</I>,
<I>word splitting</I>,
+<I>pathname expansion</I>,
+
and
-<I>pathname expansion</I>.
+<I>quote removal .</I>
<P>
tilde expansion, parameter and variable expansion, arithmetic expansion,
and command substitution (done in a left-to-right fashion);
word splitting;
-and pathname expansion.
+pathname expansion;
+and quote removal.
<P>
On systems that can support it, there is an additional expansion
command substitution.
<P>
-After these expansions are performed, quote characters present in the
-original word are removed unless they have been quoted themselves
-(<I>quote removal</I>).
+<I>Quote removal</I> is always performed last.
+It removes quote characters present in the original word,
+not ones resulting from one of the other expansions,
+unless they have been quoted themselves.
<P>
Only brace expansion, word splitting, and pathname expansion
can increase the number of words of the expansion; other expansions
expand a single word to a single word.
The only exceptions to this are the expansions of
-"<B>$@</B>" and "<B>${</B><I>name</I><B>[@]}</B>",
+<B>dq$@dq</B>
+
+and
+<B>dq${</B><I>name</I>[@]}dq <B></B>,
+
+
+
and, in most cases, <B>$*</B> and <B>${</B><I>name</I><B>[*]}</B>
as explained above (see
<FONT SIZE=-1><B>PARAMETERS</B>).
Brace expansions may be nested. The results of each expanded
string are not sorted; left to right order is preserved.
-For example, a<B>{</B>d,c,b<B>}</B>e expands into `ade ace abe'.
+For example, a<B>{</B>d,c,b<B>}</B>e expands into
+
<P>
A sequence expression takes the form
and <I>incr</I>, an optional increment, is an integer.
When integers are supplied, the expression expands to each number between
<I>x</I> and <I>y</I>, inclusive.
-Supplied integers may be prefixed with <I>0</I> to force each term to have the
-same width.
+If the supplied integers are prefixed with <I>0</I>, each term will
+have the same width, zero-padding if necessary.
When either <I>x</I> or y begins with a zero, the shell
attempts to force all generated terms to contain the same number of digits,
zero-padding where necessary.
<A NAME="lbBA"> </A>
<H4>Tilde Expansion</H4>
-If a word begins with an unquoted tilde character (`<B>ti</B>'), all of
+If a word begins with an unquoted tilde character (
+
+all of
the characters preceding the first unquoted slash (or all characters,
if there is no unquoted slash) are considered a <I>tilde-prefix</I>.
If none of the characters in the tilde-prefix are quoted, the
associated with the specified login name.
<P>
-If the tilde-prefix is a `ti+', the value of the shell variable
+If the tilde-prefix is a
+
+the value of the shell variable
<FONT SIZE=-1><B>PWD</B>
</FONT>
replaces the tilde-prefix.
-If the tilde-prefix is a `ti-', the value of the shell variable
+If the tilde-prefix is a
+
+the value of the shell variable
<FONT SIZE=-1><B>OLDPWD</B>,
</FONT>
if it is set, is substituted.
If the characters following the tilde in the tilde-prefix consist
of a number <I>N</I>, optionally prefixed
-by a `+' or a `-', the tilde-prefix is replaced with the corresponding
+by a
+
+or a
+
+the tilde-prefix is replaced with the corresponding
element from the directory stack, as it would be displayed by the
<B>dirs</B>
builtin invoked with the tilde-prefix as an argument.
If the characters following the tilde in the tilde-prefix consist of a
-number without a leading `+' or `-', `+' is assumed.
+number without a leading
+
+or
+
+
+is assumed.
<P>
If the login name is invalid, or the tilde expansion fails, the word
<A NAME="lbBB"> </A>
<H4>Parameter Expansion</H4>
-The `<B>$</B>' character introduces parameter expansion,
+The
+
+character introduces parameter expansion,
command substitution, or arithmetic expansion. The parameter name
or symbol to be expanded may be enclosed in braces, which
are optional but serve to protect the variable to be expanded from
interpreted as part of the name.
<P>
-When braces are used, the matching ending brace is the first `<B>}</B>'
+When braces are used, the matching ending brace is the first
+
not escaped by a backslash or within a quoted string, and not within an
embedded arithmetic expansion, command substitution, or parameter
expansion.
</FONT>
below).
-<P>
+<DT><DD>
If <I>offset</I> evaluates to a number less than zero, the value
is used as an offset in characters
from the end of the value of <I>parameter</I>.
<I>offset</I> and that result.
Note that a negative offset must be separated from the colon by at least
one space to avoid being confused with the <B>:-</B> expansion.
-<P>
+<DT><DD>
If <I>parameter</I> is <B>@</B> or <B>*</B>, the result is <I>length</I>
positional parameters beginning at <I>offset</I>.
A negative <I>offset</I> is taken relative to one greater than the greatest
parameter (or 0 if there are no positional parameters).
It is an expansion error if <I>length</I> evaluates to a number less than
zero.
-<P>
+<DT><DD>
If <I>parameter</I> is an indexed array name subscripted by @ or *,
the result is the <I>length</I>
members of the array beginning with ${<I>parameter</I>[<I>offset</I>]}.
index of the specified array.
It is an expansion error if <I>length</I> evaluates to a number less than
zero.
-<P>
+<DT><DD>
Substring expansion applied to an associative array produces undefined
results.
-<P>
+<DT><DD>
Substring indexing is zero-based unless the positional parameters
are used, in which case the indexing starts at 1 by default.
If <I>offset</I> is 0, and the positional parameters are used, <B>$0</B> is
then the result of the expansion is the expanded value of
<I>parameter</I>
-with the shortest matching pattern (the ``<B>#</B>'' case) or the
-longest matching pattern (the ``<B>##</B>'' case) deleted.
+with the shortest matching pattern (the
+
+case) or the longest matching pattern (the
+
+case) deleted.
If
<I>parameter</I>
then the result of the expansion is the expanded value of
<I>parameter</I>
-with the shortest matching pattern (the ``<B>%</B>'' case) or the
-longest matching pattern (the ``<B>%%</B>'' case) deleted.
+with the shortest matching pattern (the
+
+case) or the longest matching pattern (the
+
+case) deleted.
If
<I>parameter</I>
below.
In the first form above, only the first match is replaced.
-If there are two slashes separating <I>parameter</I> and <I>pattern</I>
+If there are two slashes separating <I>parameter</I> and <I>pattern</I>
(the second form above), all matches of <I>pattern</I> are
replaced with <I>string</I>.
If <I>pattern</I> is preceded by <B>#</B> (the third form above),
If <I>string</I> is null,
matches of <I>pattern</I> are deleted
and the <B>/</B> following <I>pattern</I> may be omitted.
-<P>
+<DT><DD>
If the <B>patsub_replacement</B> shell option is enabled using <B>shopt</B>,
any unquoted instances of <B>&</B> in <I>string</I> are replaced with the
matching portion of <I>pattern</I>.
-<P>
+<DT><DD>
Quoting any part of <I>string</I> inhibits replacement in the
expansion of the quoted portion, including replacement strings stored
in shell variables.
shell programmers should quote any occurrences of <B>&</B>
they want to be taken literally in the replacement
and ensure any instances of <B>&</B> they want to be replaced are unquoted.
-<P>
+<DT><DD>
If the
<B>nocasematch</B>
The expansion is either a transformation of the value of <I>parameter</I>
or information about <I>parameter</I> itself, depending on the value of
<I>operator</I>. Each <I>operator</I> is a single letter:
+</DL>
<P>
+
<DL COMPACT><DT><DD>
<DL COMPACT>
<DD>
The expansion is a string that is the value of <I>parameter</I> with backslash
-escape sequences expanded as with the <B>$aq...aq</B> quoting mechanism.
+escape sequences expanded as with the <B>$aq</B>...<B>aq</B>
+quoting mechanism.
<DT><B>P</B>
<DD>
the operation is applied to each member of the
array in turn, and the expansion is the resultant list.
<P>
+
The result of the expansion is subject to word splitting and pathname
expansion as described below.
</DL>
-</DL>
<A NAME="lbBC"> </A>
<H4>Command Substitution</H4>
<P>
Any side effects of <I>command</I> take effect immediately
-in the current execution environment and persist in the current
+in the current execution environment and persist in the current
environment after the command completes (e.g., the <B>exit</B> builtin
will exit the shell).
<P>
</FONT>
is unset, word splitting behaves as if it contained the default value
-of
+of
<B><space><tab><newline></B>.
<P>
-Explicit null arguments (<B>""</B> or <B>aqaq</B>) are retained
+Explicit null arguments (<B>dqdq</B> or
+<B>aqaq</B>) are retained
and passed to commands as empty strings.
Unquoted implicit null arguments, resulting from the expansion of
parameters that have no values, are removed.
When a quoted null argument appears as part of a word whose expansion is
non-null, the null argument is removed.
That is, the word
-<TT>-daqaq</TT> becomes <TT>-d</TT> after word splitting and
-null argument removal.
+
+becomes
+
+after word splitting and null argument removal.
<P>
Note that if no expansion occurs, no splitting
of alphabetic characters.
When a pattern is used for pathname expansion,
the character
-<B>``.''</B>
at the start of a name or immediately following a slash
must be matched explicitly, unless the shell option
is set.
In order to match the filenames
-<B>``.''</B>
and
-<B>``..''</B>,
-the pattern must begin with ``.'' (for example, ``.?''),
+the pattern must begin with
+
+(for example,
+
even if
<B>dotglob</B>
<B>globskipdots</B>
shell option is enabled, the filenames
-<B>``.''</B>
and
-<B>``..''</B>
-are never matched, even if the pattern begins with a
-<B>``.''</B>.
+never match, even if the pattern begins with a
When not matching pathnames, the
-<B>``.''</B>
character is not treated specially.
When matching a pathname, the slash character must always be
</FONT>
is performed without regard to case.
The filenames
-<B>``.''</B>
and
-<B>``..''</B>
are always ignored when
<FONT SIZE=-1><B>GLOBIGNORE</B>
</FONT>
-is set and not null. However, setting
+is set and not null.
+However, setting
<FONT SIZE=-1><B>GLOBIGNORE</B>
</FONT>
<B>dotglob</B>
shell option, so all other filenames beginning with a
-<B>``.''</B>
-
+Q .
will match.
To get the old behavior of ignoring filenames beginning with a
-<B>``.''</B>,
make
-<B>``.*''</B>
one of the patterns in
<FONT SIZE=-1><B>GLOBIGNORE</B>.
<P>
Any character that appears in a pattern, other than the special pattern
-characters described below, matches itself. The NUL character may not
-occur in a pattern. A backslash escapes the following character; the
-escaping backslash is discarded when matching.
+characters described below, matches itself.
+The NUL character may not occur in a pattern.
+A backslash escapes the following character; the escaping backslash is
+discarded when matching.
The special pattern characters must be quoted if
they are to be matched literally.
<P>
<DD>
Matches any single character.
-<DT><B>[...]</B>
+<DT><B>[</B>...<B>]</B>
<DD>
-Matches any one of the enclosed characters. A pair of characters
-separated by a hyphen denotes a
+Matches any one of the enclosed characters.
+A pair of characters separated by a hyphen denotes a
<I>range expression</I>;
any character that falls between those two characters, inclusive,
using the current locale's collating sequence and character set,
may be matched by including it as the first character
in the set.
-<P>
-
+<DT><DD>
Within
<B>[</B>
<I>character classes</I> can be specified using the syntax
<B>[:</B><I>class</I><B>:]</B>, where <I>class</I> is one of the
following classes defined in the POSIX standard:
-</DL>
-<P>
-
+<DT><DD>
<DL COMPACT><DT><DD>
<B>
</B>
alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit
-<BR>
+</DL>
+<DT><DD>
A character class matches any character belonging to that class.
The <B>word</B> character class matches letters, digits, and the character _.
-<P>
-
-
+<DT><DD>
Within
<B>[</B>
<B>[=</B><I>c</I><B>=]</B>, which matches all characters with the
same collation weight (as defined by the current locale) as
the character <I>c</I>.
-<P>
-
-
+<DT><DD>
Within
<B>[</B>
the syntax <B>[.</B><I>symbol</I><B>.]</B> matches the collating symbol
<I>symbol</I>.
-</DL>
-
-</DL>
-
+</DL></DL>
<P>
sub-patterns:
<P>
+
<DL COMPACT><DT><DD>
<DL COMPACT>
<DT><B>?(</B><I>pattern-list</I><B>)</B><DD>
When matching filenames, the <B>dotglob</B> shell option determines
the set of filenames that are tested:
when <B>dotglob</B> is enabled, the set of filenames includes all files
-beginning with ``.'', but ``.'' and ``..'' must be matched by a
-pattern or sub-pattern that begins with a dot;
+beginning with
+
+but
+
+and
+
+must be matched by a pattern or sub-pattern that begins with a dot;
when it is disabled, the set does not
-include any filenames beginning with ``.'' unless the pattern
-or sub-pattern begins with a ``.''.
-As above, ``.'' only has a special meaning when matching filenames.
+include any filenames beginning with
+
+unless the pattern or sub-pattern begins with a
+
+As above,
+
+only has a special meaning when matching filenames.
<P>
Complicated extended pattern matching against long strings is slow,
<B>aq</B>,
-and <B>"</B> that did not result from one of the above
+and <B>dq</B> that did not result from one of the above
expansions are removed.
<A NAME="lbBI"> </A>
<H3>REDIRECTION</H3>
replaces the word with the alias value, and reads that value as if it
had been read instead of the word.
The shell doesn't look at any characters following the word before
-attempting alias substitution.
+attempting alias substitution.
<P>
The characters <B>/</B>, <B>$</B>, <B>`</B>, and <B>=</B> and
In the following description, the <I>current scope</I> is a currently-
executing function.
Previous scopes consist of that function's caller and so on,
-back to the "global" scope, where the shell is not executing
-any shell function.
+back to the
+
+scope, where the shell is not executing any shell function.
Consequently, a local variable at the current scope is a variable
declared using the <B>local</B> or <B>declare</B> builtins in the
function that is currently executing.
<P>
-Local variables "shadow" variables with the same name declared at
+Local variables
+
+variables with the same name declared at
previous scopes.
For instance, a local variable declared in a function
hides a global variable of the same name: references and assignments
to reach the current function.
The value of a variable that a function sees depends
on its value within its caller, if any, whether that caller is
-the "global" scope or another shell function.
+the global
+scope or another shell function.
This is also the value that a local variable
-declaration "shadows", and the value that is restored when the function
-returns.
+declaration shadows,
+and the value that is restored when the function returns.
<P>
For example, if a variable <I>var</I> is declared as local in function
links and operate on the target of the link, rather than the link itself.
<P>
-
When used with <B>[[</B>,
or when the shell is in <I>posix mode</I>,
the <B><</B> and <B>></B> operators sort
the <B>test</B> command sorts using ASCII ordering.
<P>
+
<DL COMPACT>
<DT><B>-a </B><I>file</I>
<DT><B>-k </B><I>file</I>
<DD>
-True if <I>file</I> exists and its ``sticky'' bit is set.
+True if <I>file</I> exists and its
+
+bit is set.
<DT><B>-p </B><I>file</I>
<DD>
is invoked in a separate execution environment that consists of
the following.
Unless otherwise noted, the values are inherited from the shell.
-
<DL COMPACT>
<DT>*<DD>
the shell's open files, plus any modifications and additions specified
cannot affect the shell's execution environment.
<P>
-Subshells spawned to execute command substitutions inherit the value of
-the <B>-e</B> option from the parent shell. When not in <I>posix mode</I>,
+When the shell is in
+<I>posix mode</I>,
+subshells spawned to execute command substitutions inherit the value of
+the <B>-e</B> option from their parent shell.
+When not in <I>posix mode</I>,
<B>bash</B> clears the <B>-e</B> option in such subshells.
+See the
+description of the <B>inherit_errexit</B> shell option below
+for how to control this behavior when not in posix mode.
<P>
If a command is followed by a <B>&</B> and job control is not active, the
to all processes in that process group.
<P>
-When <B>bash</B> is running without job control enabled and receives
+When <B>bash</B> is running without job control enabled and receives
<FONT SIZE=-1><B>SIGINT</B>
</FONT>
processes are those whose process group ID differs from the terminal's;
such processes are immune to keyboard-generated signals.
Only foreground processes are allowed to read from or, if the
-user so specifies with <TT>stty tostop</TT>, write to the
-terminal.
+user so specifies with
+
+write to the terminal.
Background processes which attempt to read from (write to when
-<TT>stty tostop</TT> is in effect) the
-terminal are sent a
+
+is in effect) the terminal are sent a
<FONT SIZE=-1><B>SIGTTIN (SIGTTOU)</B>
</FONT>
<B>%1</B>
is a synonym for
-<B>``fg %1''</B>,
+
bringing job 1 from the background into the foreground.
Similarly,
-<B>``%1 &''</B>
resumes job 1 in the background, equivalent to
-<B>``bg %1''</B>.
+
<P>
The shell learns immediately whenever a job changes state.
<DT><B>\d</B>
<DD>
-the date in "Weekday Month Date" format (e.g., "Tue May 26")
+the date in
+
+format (e.g.,
+
<DT><B>\D{</B><I>format</I>}
<DD>
-the <I>format</I> is passed to <I>strftime</I>(3) and the result is inserted
+the <I>format</I> is passed to
+<I>strftime</I>(3)
+
+and the result is inserted
into the prompt string; an empty <I>format</I> results in a locale-specific
time representation. The braces are required
<DT><B>\e</B>
<DT><B>\h</B>
<DD>
-the hostname up to the first `.'
+the hostname up to the first
+
<DT><B>\H</B>
<DD>
C-Meta-u: universal-argument
</DL>
+<P>
+
into the
<I>inputrc</I>
is the name of a key spelled out in English. For example:
<P>
+
<DL COMPACT><DT><DD>
-Control-u: universal-argument
-<BR>
+<PRE>
+Control-u: universal-argument
Meta-Rubout: backward-kill-word
-<BR>
+Control-o: dq> outputdq
+</PRE>
+
-Control-o: "> output"
</DL>
<P>
is bound to run the macro
expressed on the right hand side (that is, to insert the text
-<TT>> output</TT>
into the line).
<P>
-In the second form, <B>"keyseq"</B>:<I>function-name</I> or <I>macro</I>,
+In the second form,
+<B>dqkeyseqdq</B>:<I>function-name</I> or <I>macro</I>,
<B>keyseq</B>
differs from
used, as in the following example, but the symbolic character names
are not recognized.
<P>
+
<DL COMPACT><DT><DD>
-"\C-u": universal-argument
-<BR>
-"\C-x\C-r": re-read-init-file
-<BR>
+<PRE>
+dq\C-udq: universal-argument
+dq\C-x\C-rdq: re-read-init-file
+dq\e[11tidq: dqFunction Key 1dq
+</PRE>
+
-"\e[11ti": "Function Key 1"
</DL>
<P>
<I>ESC [ 1 1 ti</I>
is bound to insert the text
-<TT>Function Key 1</TT>.
<P>
<DD>
backslash
-<DT><B>\</B>
+<DT><B>\dq</B>
<DD>
-literal "
+literal dq
<DT><B>\aq</B>
<DD>
Unquoted text is assumed to be a function name.
In the macro body, the backslash escapes described above are expanded.
Backslash will quote any other character in the macro text,
-including " and aq.
+including dq and aq.
<P>
<B>Bash</B>
(without regard to case).
Unrecognized variable names are ignored.
-When a variable value is read, empty or null values, "on" (case-insensitive),
-and "1" are equivalent to <B>On</B>. All other values are equivalent to
+When readline reads a variable value, empty or null values,
+
+(case-insensitive), and
+
+are equivalent to <B>On</B>.
+All other values are equivalent to
<B>Off</B>.
The variables and their default values are:
<P>
<DL COMPACT>
-<DT><B>active-region-start-color </B>
+<DT><B>active-region-start-color</B>
<DD>
A string variable that controls the text color and background when displaying
This variable is reset to the default value whenever the terminal type changes.
The default value is the string that puts the terminal in standout mode,
as obtained from the terminal's terminfo description.
-A sample value might be <TT>"\e[01;33m"</TT>.
-<DT><B>active-region-end-color </B>
+A sample value might be
+
+<DT><B>active-region-end-color</B>
<DD>
-A string variable that "undoes" the effects of <B>active-region-start-color</B>
-and restores "normal" terminal display appearance after displaying text
-in the active region.
+A string variable that
+
+the effects of <B>active-region-start-color</B>
+and restores
+
+terminal display appearance after displaying text in the active region.
This string must not take up any physical character positions on the display,
so it should consist only of terminal escape sequences.
It is output to the terminal after displaying the text in the active region.
This variable is reset to the default value whenever the terminal type changes.
The default value is the string that restores the terminal from standout mode,
as obtained from the terminal's terminfo description.
-A sample value might be <TT>"\e[0m"</TT>.
+A sample value might be
+
<DT><B>bell-style (audible)</B>
<DD>
<DT><B>bind-tty-special-chars (On)</B>
<DD>
-If set to <B>On</B> (the default), readline attempts to bind the control
-characters that are
-treated specially by the kernel's terminal driver to their
-readline equivalents.
+If set to <B>On</B> (the default), readline attempts to bind
+the control characters that are treated specially by the kernel's
+terminal driver to their readline equivalents.
These override the default readline bindings described here.
-Type <TT>stty -a</TT> at a bash prompt to see your current terminal settings,
+Type
+
+at a <B>bash</B> prompt to see your current terminal settings,
including the special control characters (usually <B>cchars</B>).
<DT><B>blink-matching-paren (Off)</B>
The color definitions are taken from the value of the <B>LS_COLORS</B>
environment variable.
If there is a color definition in <B>$LS_COLORS</B> for the custom suffix
-"readline-colored-completion-prefix", readline uses this color for
+
+readline uses this color for
the common prefix instead of its default.
<DT><B>colored-stats (Off)</B>
colors to indicate their file type.
The color definitions are taken from the value of the <B>LS_COLORS</B>
environment variable.
-<DT><B>comment-begin (``#'')</B>
+
+
+
+<DT><B>comment-begin (</B>
<DD>
+
The string that is inserted when the readline
<B>insert-comment</B>
escape character (in effect, using escape as the <I>meta prefix</I>).
The default is <I>On</I>, but readline will set it to <I>Off</I> if the
locale contains eight-bit characters.
-This variable is dependent on the <B>LC_CTYPE</B> locale category, and
+This variable is dependent on the <B>LC_CTYPE</B> locale category, and
may change if the locale is changed.
<DT><B>disable-completion (Off)</B>
<DD>
The <I>point</I> is the current cursor position, and <I>mark</I> refers
to a saved cursor position.
-The text between the point and mark is referred to as the <I>region</I>.
+The text between the point and mark is referred to as the <I>region</I>.
When this variable is set to <I>On</I>, readline allows certain commands
-to designate the region as <I>active</I>.
+to designate the region as <I>active</I>.
When the region is active, readline highlights the text in the region using
the value of the <B>active-region-start-color</B>, which defaults to the
string that enables
locale contains eight-bit characters.
This variable is dependent on the <B>LC_CTYPE</B> locale category, and
may change if the locale is changed.
-<DT><B>isearch-terminators (``C-[C-J'')</B>
+<DT><B>isearch-terminators (</B>
<DD>
+
The string of characters that should terminate an incremental
search without subsequently executing the character as a command.
If this variable has not been given a value, the characters
<DT><B>match-hidden-files (On)</B>
<DD>
-This variable, when set to <B>On</B>, causes readline to match files whose
-names begin with a `.' (hidden files) when performing filename
-completion.
-If set to <B>Off</B>, the leading `.' must be
-supplied by the user in the filename to be completed.
+This variable, when set to <B>On</B>, forces readline to match files whose
+names begin with a
+
+(hidden files) when performing filename completion.
+If set to <B>Off</B>, the user must include the leading
+
+in the filename to be completed.
<DT><B>menu-complete-display-prefix (Off)</B>
<DD>
sequence.
The default is <I>Off</I>, but readline will set it to <I>On</I> if the
locale contains eight-bit characters.
-This variable is dependent on the <B>LC_CTYPE</B> locale category, and
+This variable is dependent on the <B>LC_CTYPE</B> locale category, and
may change if the locale is changed.
<DT><B>page-completions (On)</B>
before returning when <B>accept-line</B> is executed. By default,
history lines may be modified and retain individual undo lists across
calls to <B>readline</B>.
-<DT><B>search-ignore-case (Off) </B>
+<DT><B>search-ignore-case (Off)</B>
<DD>
If set to <B>On</B>, readline performs incremental and non-incremental
bindings and variable settings to be performed as the result
of tests. There are four parser directives used.
<DL COMPACT>
-<DT><B>$if</B><DD>
+<DT><B>$if</B>
+
+<DD>
The
<B>$if</B>
unless otherwise noted, no characters are required to isolate it.
<DL COMPACT><DT><DD>
<DL COMPACT>
-<DT><B>mode</B><DD>
+<DT><B>mode</B>
+
+<DD>
The <B>mode=</B> form of the <B>$if</B> directive is used to test
whether readline is in emacs or vi mode.
This may be used in conjunction
with the <B>set keymap</B> command, for instance, to set bindings in
the <I>emacs-standard</I> and <I>emacs-ctlx</I> keymaps only if
readline is starting out in emacs mode.
-<DT><B>term</B><DD>
+<DT><B>term</B>
+
+<DD>
The <B>term=</B> form may be used to include terminal-specific
key bindings, perhaps to bind the key sequences output by the
terminal's function keys. The word on the right side of the
<I>sun-cmd</I>,
for instance.
-<DT><B>version</B><DD>
+<DT><B>version</B>
+
+<DD>
The <B>version</B> test may be used to perform comparisons against
specific readline versions.
The <B>version</B> expands to the current readline version.
is assumed to be <B>0</B>.
The operator may be separated from the string <B>version</B>
and from the version number argument by whitespace.
-<DT><B>application</B><DD>
-The <B>application</B> construct is used to include
-application-specific settings. Each program using the readline
+<DT><I>application</I>
+
+<DD>
+The <I>application</I> construct is used to include
+application-specific settings.
+Each program using the readline
library sets the <I>application name</I>, and an initialization
file can test for a particular value.
This could be used to bind key sequences to functions useful for
a specific program. For instance, the following command adds a
key sequence that quotes the current or previous word in <B>bash</B>:
+</DL>
<P>
+
<DL COMPACT><DT><DD>
+
<PRE>
<B>$if</B> Bash
# Quote the current or previous word
-"\C-xq": "\eb\"\ef\""
+dq\C-xqdq: dq\eb\dq\ef\dqdq
<B>$endif</B>
</PRE>
+
</DL>
-<DT><I>variable</I><DD>
+<DL COMPACT>
+<DT><I>variable</I>
+
+<DD>
The <I>variable</I> construct provides simple equality tests for readline
variables and values.
The permitted comparison operators are <I>=</I>, <I>==</I>, and <I>!=</I>.
tested against the values <I>on</I> and <I>off</I>.
</DL></DL>
-<DT><B>$endif</B><DD>
+<DT><B>$endif</B>
+
+<DD>
This command, as seen in the previous example, terminates an
<B>$if</B> command.
-<DT><B>$else</B><DD>
+<DT><B>$else</B>
+
+<DD>
Commands in this branch of the <B>$if</B> directive are executed if
the test fails.
-<DT><B>$include</B><DD>
+<DT><B>$include</B>
+
+<DD>
This directive takes a single filename as an argument and reads commands
and bindings from that file. For example, the following directive
would read <A HREF="file:/etc/inputrc"><I>/etc/inputrc</I></A>:
+</DL>
<P>
+
<DL COMPACT><DT><DD>
<PRE>
<B>$include</B> <A HREF="file:/etc/inputrc"><I>/etc/inputrc</I></A>
</DL>
-</DL>
<A NAME="lbCL"> </A>
<H4>Searching</H4>
Readline remembers the last incremental search string. If two
Control-Rs are typed without any intervening characters defining a
-new search string, any remembered search string is used.
+new search string, readline uses any remembered search string.
<P>
Non-incremental searches read the entire search string before starting
<DT><B>reverse-search-history (C-r)</B>
<DD>
-Search backward starting at the current line and moving `up' through
-the history as necessary. This is an incremental search.
+Search backward starting at the current line and moving
+
+through the history as necessary.
+This is an incremental search.
<DT><B>forward-search-history (C-s)</B>
<DD>
-Search forward starting at the current line and moving `down' through
-the history as necessary. This is an incremental search.
+Search forward starting at the current line and moving
+
+through the history as necessary.
+This is an incremental search.
<DT><B>non-incremental-reverse-search-history (M-p)</B>
<DD>
in the previous command begin with word 0). A negative argument
inserts the <I>n</I>th word from the end of the previous command.
Once the argument <I>n</I> is computed, the argument is extracted
-as if the "!<I>n</I>" history expansion had been specified.
+as if the
+
+history expansion had been specified.
<DT><B>yank-last-arg (M-., M-_)</B>
<DD>
the direction to move through the history. A negative argument switches
the direction through the history (back or forward).
The history expansion facilities are used to extract the last word,
-as if the "!$" history expansion had been specified.
+as if the
+
+history expansion had been specified.
<DT><B>shell-expand-line (M-C-e)</B>
<DD>
This performs alias and history expansion,
<B>$</B>aq<I>string</I>aq and <B>$</B>dq<I>string</I>dq quoting,
tilde expansion, parameter and variable expansion, arithmetic expansion,
+command and process substitution,
word splitting, and quote removal.
+An explicit argument suppresses command and process substitution.
See
<FONT SIZE=-1><B>HISTORY EXPANSION</B>
</FONT>
below for a description of history expansion.
-<DT><B>history-expand-line (M-^)</B>
+<DT><B>history-expand-line (M-ha)</B>
<DD>
Perform history expansion on the current line.
<DD>
The character indicating end-of-file as set, for example, by
-<TT>stty</TT>.
+<I>stty</I>(1).
If this character is read when there are no characters
on the line, and point is at the beginning of the line, readline
<DD>
Insert a tab character.
-<DT><B>self-insert (a, b, A, 1, !, ...)</B>
+<DT><B>self-insert (a, b, A, 1, !, </B>...)
<DD>
Insert the character typed.
<DL COMPACT>
-<DT><B>digit-argument (M-0, M-1, ..., M--)</B>
+<DT><B>digit-argument (M-0, M-1, </B>..., M--)
<DD>
Add this digit to the argument already accumulating, or start a new
Read enough characters to consume a multi-key sequence such as those
defined for keys like Home and End. Such sequences begin with a
Control Sequence Indicator (CSI), usually ESC-[. If this sequence is
-bound to "\[", keys producing such sequences will have no effect
+bound to
+
+keys producing such sequences will have no effect
unless explicitly bound to a readline command, instead of inserting
stray characters into the editing buffer. This is unbound by default,
but usually bound to ESC-[.
For instance, assuming that there is a library of compspecs, each kept in a
file corresponding to the name of the command, the following default
completion function would load completions dynamically:
-<P>
-
-<TT>_completion_loader()
-<BR>
+<DL COMPACT><DT><DD>
+<PRE>
+_completion_loader()
{
+ . dq/etc/bash_completion.d/$1.shdq
+\
<BR>
-<BR> . "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124
<BR>
-
+
+>/dev/null 2>&1 && return 124
}
+complete -D -F _completion_loader
+\
<BR>
-complete -D -F _completion_loader -o bashdefault -o default
<BR>
+
+-o bashdefault -o default
+</PRE>
+
+
+</DL>
-</TT>
<A NAME="lbCW"> </A>
<H3>HISTORY</H3>
<DT><B>!!</B>
<DD>
-Refer to the previous command. This is a synonym for `!-1'.
+Refer to the previous command. This is a synonym for
+
<DT><B>!</B><I>string</I>
<DD>
<I>string2</I>.
Equivalent to
-``!!:s<FONT SIZE=+2>ha</FONT><I>string1</I><FONT SIZE=+2>ha</FONT><I>string2</I><FONT SIZE=+2>ha</FONT>''
+
(see <B>Modifiers</B> below).
<DT><B>!#</B>
<DT><B>%</B>
<DD>
-The first word matched by the most recent `?<I>string</I>?' search,
+The first word matched by the most recent
+
+search,
if the search string begins with a character that is part of a word.
<DT><I>x</I><B>-</B>y
<DD>
-A range of words; `-<I>y</I>' abbreviates `0-<I>y</I>'.
+A range of words;
+
+abbreviates
+
<DT><B>*</B>
<DD>
-All of the words but the zeroth. This is a synonym
-for `<I>1-$</I>'. It is not an error to use
+All of the words but the zeroth.
+This is a synonym for
+
+It is not an error to use
<B>*</B>
if there is just one
<H4>Modifiers</H4>
After the optional word designator, there may appear a sequence of
-one or more of the following modifiers, each preceded by a `:'.
+one or more of the following modifiers, each preceded by a
+
These modify, or edit, the word or words selected from the history event.
<P>
<DT><B>g</B>
<DD>
-Cause changes to be applied over the entire event line. This is
-used in conjunction with `<B>:s</B>' (e.g., `<B>:gs/</B><I>old</I>/<I>new</I>/')
-or `<B>:&</B>'. If used with
-`<B>:s</B>', any delimiter can be used
-in place of /, and the final delimiter is optional
+Cause changes to be applied over the entire event line.
+This is used in conjunction with
+
+(e.g.,
+
+or
+
+If used with
+
+any delimiter can be used in place of /,
+and the final delimiter is optional
if it is the last character of the event line.
An <B>a</B> may be used as a synonym for <B>g</B>.
<DT><B>G</B>
<DD>
-Apply the following `<B>s</B>' or `<B>&</B>' modifier once to each word
-in the event line.
+Apply the following
+
+or
+
+modifier once to each word in the event line.
</DL>
<A NAME="lbDB"> </A>
require <B>--</B> to prevent this interpretation.
<P>
+
<DL COMPACT>
<DT><B>:</B> [<I>arguments</I>]<DD>
and performing any specified
redirections.
The return status is zero.
-<DT><B> . </B> <I>filename</I> [<I>arguments</I>]<DD>
+<DT><B>. </B> <I>filename</I> [<I>arguments</I>]<DD>
<DT><B>source</B> <I>filename</I> [<I>arguments</I>]<DD>
<I>.inputrc</I>,
but each binding or command must be passed as a separate argument;
-e.g., '"\C-x\C-r": re-read-init-file'.
+e.g., aqdq\C-x\C-rdq: re-read-init-fileaq.
In the following descriptions, output available to be re-read is formatted
as commands that would appear in a
<B>readline</B>
</FONT>
variables to the current location of the insertion point and the saved
insertion point (the mark), respectively.
-The shell assigns any numeric argument the user supplied to the
+The shell assigns any numeric argument the user supplied to the
<FONT SIZE=-1><B>READLINE_ARGUMENT</B>
</FONT>
defines the search path for the directory containing
<I>dir</I>:
-each directory name in
+the shell searches each directory name in
<FONT SIZE=-1><B>CDPATH</B>
</FONT>
-is searched for <I>dir</I>.
+for <I>dir</I>.
Alternative directory names in
<FONT SIZE=-1><B>CDPATH</B>
<FONT SIZE=-1><B>CDPATH</B>
</FONT>
-is the same as the current directory, i.e., ``<B>.</B>''. If
+is the same as the current directory, i.e.,
+
+If
<I>dir</I>
begins with a slash (/),
When using the <B>-F</B> or <B>-C</B> options, the various shell variables
set by the programmable completion facilities, while available, will not
have useful values.
-<P>
+<DT><DD>
The matches will be generated in the same way as if the programmable
completion code had generated them directly from a completion specification
with the same flags.
If <I>word</I> is specified, only those completions matching <I>word</I>
will be displayed.
-<P>
+<DT><DD>
The return value is true unless an invalid option is supplied, or no
matches were generated.
<DT><B>complete</B> [<B>-abcdefgjksuv</B>] [<B>-o</B> <I>comp-option</I>] [<B>-DEI</B>] [<B>-A</B> <I>action</I>]<DD>
[<B>-G</B> <I>globpat</I>] [<B>-W</B> <I>wordlist</I>] [<B>-F</B> <I>function</I>] [<B>-C</B> <I>command</I>]
<BR>
-[<B>-X</B> <I>filterpat</I>] [<B>-P</B> <I>prefix</I>] [<B>-S</B> <I>suffix</I>] <I>name</I> [<I>name ...</I>]
+[<B>-X</B> <I>filterpat</I>] [<B>-P</B> <I>prefix</I>] [<B>-S</B> <I>suffix</I>] <I>name</I> [<I>name</I> ...]
<DT><B>complete</B> <B>-pr</B> [<B>-DEI</B>] [<I>name</I> ...]<DD>
Specify how arguments to each <I>name</I> should be completed.
-If the <B>-p</B> option is supplied, or if no options are supplied,
+If the <B>-p</B> option is supplied, or if no options or <I>name</I>s
+are supplied,
existing completion specifications are printed in a way that allows
them to be reused as input.
The <B>-r</B> option removes a completion specification for
each <I>name</I>, or, if no <I>name</I>s are supplied, all
completion specifications.
The <B>-D</B> option indicates that other supplied options and actions should
-apply to the ``default'' command completion; that is, completion attempted
+apply to the
+
+command completion; that is, completion attempted
on a command for which no completion has previously been defined.
The <B>-E</B> option indicates that other supplied options and actions should
-apply to ``empty'' command completion; that is, completion attempted on a
+apply to
+
+command completion; that is, completion attempted on a
blank line.
The <B>-I</B> option indicates that other supplied options and actions should
apply to completion on the initial non-assignment word on the line, or after
If any of <B>-D</B>, <B>-E</B>, or <B>-I</B> are supplied, any other
<I>name</I> arguments are ignored; these completions only apply to the case
specified by the option.
-<P>
+<DT><DD>
The process of applying these completion specifications when word completion
is attempted is described
above under <B>Programmable Completion</B>.
-<P>
+<DT><DD>
Other options, if specified, have the following meanings.
The arguments to the <B>-G</B>, <B>-W</B>, and <B>-X</B> options
(and, if necessary, the <B>-P</B> and <B>-S</B> options)
<B>complete</B>
builtin is invoked.
-<P>
+<DT><DD>
<DL COMPACT><DT><DD>
<DL COMPACT>
The possible values of <I>option</I> are those valid for the <B>complete</B>
builtin described above.
The <B>-D</B> option indicates that other supplied options should
-apply to the ``default'' command completion; that is, completion attempted
+apply to the
+
+command completion; that is, completion attempted
on a command for which no completion has previously been defined.
The <B>-E</B> option indicates that other supplied options should
-apply to ``empty'' command completion; that is, completion attempted on a
-blank line.
+apply to
+
+command completion; that is, completion attempted on a blank line.
The <B>-I</B> option indicates that other supplied options should
apply to completion on the initial non-assignment word on the line,
or after a command delimiter such as <B>;</B> or <B>|</B>, which is usually
command name completion.
-<P>
+<DT><DD>
The return value is true unless an invalid option is supplied, an attempt
is made to modify the options for a <I>name</I> for which no completion
specification exists, or an output error occurs.
must be >= 1. If
<I>n</I>
-is greater than the number of enclosing loops, the last enclosing loop
-(the ``top-level'' loop) is resumed.
+is greater than the number of enclosing loops, the shell resumes
+the last enclosing loop
+(the
+
+loop).
The return value is 0 unless <I>n</I> is not greater than or equal to 1.
<DT><B>declare</B> [<B>-aAfFgiIlnrtux</B>] [<B>-p</B>] [<I>name</I>[=<I>value</I>] ...]<DD>
<B>-I</B>
option causes local variables to inherit the attributes
-(except the <I>nameref</I> attribute)
+(except the <I>nameref</I> attribute)
and value of any existing variable with the same
<I>name</I> at a surrounding scope.
If there is no existing variable, the local variable is initially unset.
</DL>
<P>
-Using `+' instead of `-'
+Using
+
+instead of
+
turns off the attribute instead,
with the exceptions that <B>+a</B> and <B>+A</B>
may not be used to destroy array variables and <B>+r</B> will not
The return value is 0 unless an invalid option is encountered,
an attempt is made to define a function using
-<TT>-f foo=bar</TT>,
an attempt is made to assign a value to a readonly variable,
an attempt is made to assign a value to an array variable without
using the compound assignment syntax (see
</FONT>
instead of the shell builtin version, run
-<TT>enable -n test</TT>.
+
+
+``enable -n test''.
+
+
+
+
+
The
<B>-f</B>
colon-separated list of directories in which to search for <I>filename</I>,
if <I>filename</I> does not contain a slash.
The default is system-dependent,
-and may include "." to force a search of the current directory.
+and may include
+
+to force a search of the current directory.
The
<B>-d</B>
If no options are supplied and a <I>name</I> is not a shell builtin,
<B>enable</B> will attempt to load <I>name</I> from a shared object named
<I>name</I>, as if the command were
-<TT>enable -f</TT> <I>name name</I> .
+
+
+``enable -f <I>name name</I>''.
+
+
+
+
+
The return value is 0 unless a
<I>name</I>
is not specified, it is set to
the current command for listing (so that
-<TT>fc -l -10</TT>
+
+``fc -l -10''
+
+
+
+
+
+
prints the last 10 commands) and to
<I>first</I>
is not specified, it is set to the previous
command for editing and -16 for listing.
-<P>
+<DT><DD>
The
<B>-n</B>
is used. When editing is complete, the edited commands are
echoed and executed.
-<P>
+<DT><DD>
In the second form, <I>command</I> is re-executed after each instance
of <I>pat</I> is replaced by <I>rep</I>.
<I>Command</I> is interpreted the same as <I>first</I> above.
A useful alias to use with this is
-<TT>r='fc -s'</TT>,
so that typing
-<TT>r cc</TT>
runs the last command beginning with
-<TT>cc</TT>
and typing
-<TT>r</TT>
re-executes the last command.
-<P>
+<DT><DD>
If the first form is used, the return value is 0 unless an invalid
option is encountered or
<I>first</I>
<I>jobspec</I>
specifies a job that was started without job control.
-<DT><B>getopts</B> <I>optstring</I> <I>name</I> [<I>arg ...</I>]<DD>
+<DT><B>getopts</B> <I>optstring</I> <I>name</I> [<I>arg</I> ...]<DD>
<B>getopts</B>
is used by shell procedures to parse positional parameters.
within the same shell invocation if a new set of parameters
is to be used.
-<P>
+<DT><DD>
When the end of options is encountered, <B>getopts</B> exits with a
return value greater than zero.
<FONT SIZE=-1><B>OPTIND</B>
</FONT>
is set to the index of the first non-option argument,
and <I>name</I> is set to ?.
-<P>
+<DT><DD>
<B>getopts</B>
normally parses the positional parameters, but if more arguments are
<B>getopts</B>
parses those instead.
-<P>
+<DT><DD>
<B>getopts</B>
can report errors in two ways. If the first character of
<I>optstring</I>
is not a colon.
-<P>
-If an invalid option is seen,
+<DT><DD>
+If
<B>getopts</B>
-places ? into
+detects an invalid option, it places ? into
<I>name</I>
and, if not silent,
If
<B>getopts</B>
-is silent,
-the option character found is placed in
+is silent, it assigns the option character found to
<FONT SIZE=-1><B>OPTARG</B>
</FONT>
-and no diagnostic message is printed.
-<P>
+and does not print a diagnostic message.
+<DT><DD>
If a required argument is not found, and
<B>getopts</B>
-is not silent,
-a question mark (<B>?</B>) is placed in
-<I>name</I>,
-
-<FONT SIZE=-1><B>OPTARG</B>
+is not silent, it sets the value of <I>name</I> to
+a question mark (<B>?</B>), unsets
+<FONT SIZE=-1><B>OPTARG</B>,
</FONT>
-is unset, and a diagnostic message is printed.
+and prints a diagnostic message.
If
<B>getopts</B>
-is silent, then a colon (<B>:</B>) is placed in
-<I>name</I>
-
-and
+is silent, it sets the value of <I>name</I> to a colon (<B>:</B>)
+and sets
<FONT SIZE=-1><B>OPTARG</B>
</FONT>
-is set to the option character found.
-<P>
+to the option character found.
+<DT><DD>
<B>getopts</B>
returns true if an option, specified or unspecified, is found.
<DD>
Display only a short usage synopsis for each <I>pattern</I>
-</DL>
-<P>
+</DL></DL>
+<DT><DD>
The return status is 0 unless no command matches
<I>pattern</I>.
-</DL>
-
<DT><B>history [</B><I>n</I>]<DD>
<DT><B>history</B> <B>-c</B><DD>
<DT><B>history -d</B> <I>offset</I><DD>
<DT><B>history -d</B> <I>start</I>-<I>end</I><DD>
<DT><B>history</B> <B>-anrw</B> [<I>filename</I>]<DD>
-<DT><B>history</B> <B>-p</B> <I>arg</I> [<I>arg ...</I>]<DD>
-<DT><B>history</B> <B>-s</B> <I>arg</I> [<I>arg ...</I>]<DD>
+<DT><B>history</B> <B>-p</B> <I>arg</I> [<I>arg</I> ...]<DD>
+<DT><B>history</B> <B>-s</B> <I>arg</I> [<I>arg</I> ...]<DD>
With no options, display the command
history list with line numbers. Lines listed
</FONT>
is set and not null,
-it is used as a format string for <I>strftime</I>(3) to display
-the time stamp associated with each displayed history entry.
+it is used as a format string for
+<I>strftime</I>(3)
+
+to display the time stamp associated with each displayed history entry.
No intervening blank is printed between the formatted time stamp
and the history line.
If <I>filename</I> is supplied, it is used as the
<DT><B>-a</B>
<DD>
-Append the ``new'' history lines to the history file.
+Append the
+
+history lines to the history file.
These are history lines entered since the beginning of the current
<B>bash</B> session, but not already appended to the history file.
<DT><B>-n</B>
starting with zero, from the stack.
For example:
-<TT>popd +0</TT>
removes the first directory,
-<TT>popd +1</TT>
the second.
<DT><B>-</B><I>n</I><DD>
Removes the <I>n</I>th entry counting from the right of the list
starting with zero. For example:
-<TT>popd -0</TT>
removes the last directory,
-<TT>popd -1</TT>
the next to last.
</DL>
control of the <I>format</I>.
The <B>-v</B> option causes the output to be assigned to the variable
<I>var</I> rather than being printed to the standard output.
-<P>
+<DT><DD>
The <I>format</I> is a character string which contains three types of objects:
plain characters, which are simply copied to standard output, character
escape sequences, which are converted and copied to the standard output, and
format specifications, each of which causes printing of the next successive
<I>argument</I>.
-In addition to the standard <I>printf</I>(3) format characters
+In addition to the standard
+<I>printf</I>(3)
+
+format characters
<B>csndiouxXeEfFgGaA</B>,
<B>printf</B> interprets the following additional format specifiers:
<DD>
causes <B>printf</B> to output the date-time string resulting from using
-<I>datefmt</I> as a format string for <I>strftime</I>(3).
+<I>datefmt</I> as a format string for
+<I>strftime</I>(3).
+
The corresponding <I>argument</I> is an integer representing the number of
seconds since the epoch.
Two special argument values may be used: -1 represents the current
</DL>
<P>
+Other than the case where <I>delim</I> is the empty string, <B>read</B>
+ignores any NUL characters in the input.
+<P>
+
If no
<I>names</I>
<B>$2</B>,
-<B>...</B>
-
+...,
<B>$</B><I>n</I>.
Options, if specified, have the following meanings:
<DT><B>-e</B>
<DD>
+
Exit immediately if a
<I>pipeline</I> (which may consist of a single <I>simple command</I>),
a <I>list</I>,
above),
and may cause
subshells to exit before executing all the commands in the subshell.
-<P>
-
-
+<DT><DD>
If a compound command or shell function executes in a context
where <B>-e</B> is being ignored,
none of the commands executed within the compound command or function body
a context where <B>-e</B> is ignored, that setting will not have any
effect until the compound command or the command containing the function
call completes.
+
<DT><B>-f</B>
<DD>
<DD>
The effect is as if the shell command
-<TT>IGNOREEOF=10</TT>
+
+
+``IGNOREEOF=10''
+
+
+
+
+
had been executed
(see
Same as
<B>-x</B>.
-<P>
</DL>
<P>
<DD>
Treat unset variables and parameters other than the special
-parameters "@" and "*",
-or array variables subscripted with "@" or "*",
-as an error when performing
-parameter expansion. If expansion is attempted on an
-unset variable or parameter, the shell prints an error message, and,
+parameters
+
+and
+
+or array variables subscripted with
+
+or
+
+as an error when performing parameter expansion.
+If expansion is attempted on an unset variable or parameter,
+the shell prints an error message, and,
if not interactive, exits with a non-zero status.
<DT><B>-v</B>
<P>
-
<DL COMPACT>
<DT><B>array_expand_once</B>
<DT><B>assoc_expand_once</B>
<DD>
-Deprecated; a synonym for <B>array_expand_once</B>.
+Deprecated; a synonym for <B>array_expand_once</B>.
<DT><B>autocd</B>
<DD>
If set,
<B>bash</B>
-includes filenames beginning with a `.' in the results of pathname
-expansion.
+includes filenames beginning with a
+
+in the results of pathname expansion.
The filenames
-<B>``.''</B>
and
-<B>``..''</B>
must always be matched explicitly, even if
<B>dotglob</B>
<DT><B>extquote</B>
<DD>
-If set, <B>$</B>aq<I>string</I>aq and <B>$</B>"<I>string</I>" quoting is
+If set, <B>$</B>aq<I>string</I>aq and <B>$</B>dq<I>string</I>dq quoting is
performed within <B>${</B><I>parameter</I><B>}</B> expansions
enclosed in double quotes. This option is enabled by default.
<DT><B>failglob</B>
<DD>
If set, pathname expansion will never match the filenames
-<B>``.''</B>
and
-<B>``..''</B>,
even if the pattern begins with a
-<B>``.''</B>.
This option is enabled by default.
<DT><B>globstar</B>
<DD>
If set, and a file that <B>bash</B> is checking for mail has been
-accessed since the last time it was checked, the message ``The mail in
-<I>mailfile</I> has been read'' is displayed.
+accessed since the last time it was checked,
+<B>bash</B> displays the message
+
<DT><B>no_empty_cmd_completion</B>
<DD>
If set,
<B>bash</B>
-encloses the translated results of $"..." quoting in single quotes
-instead of double quotes.
+encloses the translated results of
+<B>$dq</B>...<B>dq</B>
+
+quoting in single quotes instead of double quotes.
If the string is not translated, this has no effect.
<DT><B>nullglob</B>
<DT><B>test</B> <I>expr</I><DD>
<DT><B>[</B> <I>expr</I> <B>]</B><DD>
+
Return a status of 0 (true) or 1 (false) depending on
the evaluation of the conditional expression
<I>expr</I>.
Each operator and operand must be a separate argument.
-Expressions are composed of the primaries described
+Expressions are composed of the primaries described
above
under
</FONT>
<B>test</B> does not accept any options, nor does it accept and ignore
an argument of <B>--</B> as signifying the end of options.
-<P>
-
-
+<DT><DD>
Expressions may be combined using the following operators, listed
in decreasing order of precedence.
The evaluation depends on the number of arguments; see below.
<P>
-
<DL COMPACT>
<DT>0 arguments<DD>
The expression is false.
<DT>5 or more arguments<DD>
The expression is parsed and evaluated according to precedence
using the rules listed above.
-<P>
-
</DL>
<P>
-If the shell is not in <I>posix mode</I>,
-when used with <B>test</B> or <B>[</B>, the <B><</B> and <B>></B> operators
-sort lexicographically using ASCII ordering.
-When the shell is in <I>posix mode</I>, these operators sort using the
+When the shell is in <I>posix mode</I>, or if the expression is part
+of the <B>[[</B> command,
+the <B><</B> and <B>></B> operators sort using the
current locale.
+If the shell is not in <I>posix mode</I>, the <B>test</B> and <B>[</B>
+commands sort lexicographically using ASCII ordering.
</DL>
-
<DT><B>times</B>
<DD>
<I>sigspec</I>
is ignored by the shell and by the commands it invokes.
-<P>
-
-
+<DT><DD>
If no arguments are supplied,
<B>trap</B>
in a subshell environment (e.g., command substitution) and, as
long as they are used before <B>trap</B> is used to change a signal's
handling, will display the state of its parent's traps.
-<P>
-
-
+<DT><DD>
The
<B>-l</B>
</FONT>
prefix is optional.
-<P>
-
-
+<DT><DD>
If a
<I>sigspec</I>
is executed before every <I>simple command</I>, <I>for</I> command,
<I>case</I> command, <I>select</I> command, (( arithmetic command,
-[[ conditional command,
+[[ conditional command,
arithmetic <I>for</I> command, and before the first command executes
in a shell function (see
<FONT SIZE=-1><B>SHELL GRAMMAR</B>
is executed each time a shell function or a script executed with
the <B>.</B> or <B>source</B> builtins finishes executing.
-<P>
-
-
+<DT><DD>
If a
<I>sigspec</I>
<B>!</B>.
These are the same conditions obeyed by the <B>errexit</B> (<B>-e</B>) option.
-<P>
-
-
+<DT><DD>
When the shell is not interactive,
signals ignored upon entry to the shell cannot be trapped or reset.
Interactive shells permit trapping signals ignored on entry.
were specified as a command name,
or nothing if
-<TT>type -t name</TT>
would not return
<I>file</I>.
</FONT>
search for each <I>name</I>, even if
-<TT>type -t name</TT>
would not return
<I>file</I>.
can be supplied to restrict the output to executable files.
<B>type</B> does not consult the table of hashed commands
when using
-<B>-a </B>
+<B>-a</B>
with
<B>-p</B>,
<DT><B>-e</B>
<DD>
-The maximum scheduling priority ("nice")
+The maximum scheduling priority (
+
<DT><B>-f</B>
<DD>
<I>name</I>
is readonly or may not be unset.
-<DT><B>wait</B> [<B>-fn</B>] [-p <I>varname</I>] [<I>id ...</I>]<DD>
+<DT><B>wait</B> [<B>-fn</B>] [-p <I>varname</I>] [<I>id</I> ...]<DD>
Wait for each specified child process and return its termination status.
Each
<I>id</I>
This section does not mention behavior that is standard for a particular
version (e.g., setting <B>compat32</B> means that quoting the rhs of the regexp
matching operator quotes special regexp characters in the word, which is
-default behavior in bash-3.2 and subsequent versions).
+default behavior in bash-3.2 and subsequent versions).
<P>
If a user enables, say, <B>compat32</B>, it may affect the behavior of other
</FONT>
<P>
-Bash-5.0 is the final version for which there will be an individual shopt
-option for the previous version. Users should use
-<FONT SIZE=-1><B>BASH_COMPAT</B>
+Bash-5.0 was the final version for which there will be an individual shopt
+option for the previous version. Users should control the compatibility
+level with
+<FONT SIZE=-1><B>BASH_COMPAT</B>.
</FONT>
-on bash-5.0 and later versions.
<P>
The following table describes the behavior changes controlled by each
and <B>*</B> differently depending on whether the array is indexed or
associative, and differently than in previous versions.
<DT>*<DD>
-arithmetic commands ( ((...)) ) and the expressions in an arithmetic for
+arithmetic commands (
+<B>((</B>...<B>))</B>
+
+) and the expressions in an arithmetic for
statement can be expanded more than once
<DT>*<DD>
expressions used as arguments to arithmetic operators in the <B>[[</B>
the expressions in substring parameter brace expansion can be
expanded more than once
<DT>*<DD>
-the expressions in the $(( ... )) word expansion can be expanded
-more than once
+the expressions in the
+<B>$((</B>...<B>))</B>
+
+word expansion can be expanded more than once
<DT>*<DD>
arithmetic expressions used as indexed array subscripts can be
expanded more than once
<DT>*<DD>
-<B>test -v</B>, when given an argument of <B>A[@]</B>, where <B>AP is
+<B>test -v</B>, when given an argument of <B>A[@]</B>, where <B>A</B> is
an existing associative array, will return true if the array has any set
elements.
-Bash-5.2 will look for and report on a key named @</B>.
+Bash-5.2 will look for and report on a key named <B>@</B>.
<DT>*<DD>
the ${<I>parameter</I><B>[:]=</B><I>value</I>} word expansion will return
<I>value</I>, before any variable-specific transformations have been
command to submit a bug report.
If you have a fix, you are encouraged to mail that as well!
-Suggestions and `philosophical' bug reports may be mailed
-to <I><A HREF="mailto:bug-bash@gnu.org">bug-bash@gnu.org</A></I> or posted to the Usenet
+You may send suggestions and
+
+bug reports to <I><A HREF="mailto:bug-bash@gnu.org">bug-bash@gnu.org</A></I> or post them to the Usenet
newsgroup
<A HREF="news:gnu.bash.bug">gnu.bash.bug</A>.
<DT>The hardware and operating system<DD>
<DT>The compiler used to compile<DD>
<DT>A description of the bug behaviour<DD>
-<DT>A short script or `recipe' which exercises the bug<DD>
+<DT>A short script or <DD>
+
+which exercises the bug
</DL>
<P>
Shell builtin commands and functions are not stoppable/restartable.
<P>
-Compound commands and command sequences of the form `a ; b ; c'
+Compound commands and command sequences of the form
+
are not handled gracefully when process suspension is attempted.
When a process is stopped, the shell immediately executes the next
command in the sequence.
-It suffices to place the sequence of commands between
-parentheses to force it into a subshell, which may be stopped as
-a unit.
+It suffices to place the sequence of commands between parentheses to
+force it into a subshell, which may be stopped as a unit,
+or to start the command in the background and immediately
+bring it into the foreground.
<P>
Array variables may not (yet) be exported.
<HR>
<TABLE WIDTH=100%>
<TR>
-<TH ALIGN=LEFT width=33%>GNU Bash 5.3<TH ALIGN=CENTER width=33%>2023 December 14<TH ALIGN=RIGHT width=33%>BASH(1)
+<TH ALIGN=LEFT width=33%>GNU Bash 5.3<TH ALIGN=CENTER width=33%>2024 February 5<TH ALIGN=RIGHT width=33%>BASH(1)
</TR>
</TABLE>
<HR>
<DT><A HREF="#lbDI">BUGS</A><DD>
</DL>
<HR>
-This document was created by man2html from /usr/local/src/bash/bash-20231212/doc/bash.1.<BR>
-Time: 14 December 2023 16:39:25 EST
+This document was created by man2html from /usr/local/src/bash/bash-20240205/doc/bash.1.<BR>
+Time: 07 February 2024 09:26:02 EST
</BODY>
</HTML>
-This is bash.info, produced by makeinfo version 6.8 from bashref.texi.
+This is bash.info, produced by makeinfo version 7.1 from bashref.texi.
This text is a brief description of the features that are present in the
-Bash shell (version 5.3, 14 December 2023).
+Bash shell (version 5.3, 2 February 2024).
- This is Edition 5.3, last updated 14 December 2023, of 'The GNU Bash
-Reference Manual', for 'Bash', Version 5.3.
+ This is Edition 5.3, last updated 2 February 2024, of ‘The GNU Bash
+Reference Manual’, for ‘Bash’, Version 5.3.
- Copyright (C) 1988-2023 Free Software Foundation, Inc.
+ Copyright © 1988-2023 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
*************
This text is a brief description of the features that are present in the
-Bash shell (version 5.3, 14 December 2023). The Bash home page is
+Bash shell (version 5.3, 2 February 2024). The Bash home page is
<http://www.gnu.org/software/bash/>.
- This is Edition 5.3, last updated 14 December 2023, of 'The GNU Bash
-Reference Manual', for 'Bash', Version 5.3.
+ This is Edition 5.3, last updated 2 February 2024, of ‘The GNU Bash
+Reference Manual’, for ‘Bash’, Version 5.3.
Bash contains features that appear in other popular shells, and some
features that only appear in Bash. Some of the shells that Bash has
-borrowed concepts from are the Bourne Shell ('sh'), the Korn Shell
-('ksh'), and the C-shell ('csh' and its successor, 'tcsh'). The
+borrowed concepts from are the Bourne Shell (‘sh’), the Korn Shell
+(‘ksh’), and the C-shell (‘csh’ and its successor, ‘tcsh’). The
following menu breaks the features up into categories, noting which
features were inspired by other shells and which are specific to Bash.
=================
Bash is the shell, or command language interpreter, for the GNU
-operating system. The name is an acronym for the 'Bourne-Again SHell',
+operating system. The name is an acronym for the ‘Bourne-Again SHell’,
a pun on Stephen Bourne, the author of the direct ancestor of the
-current Unix shell 'sh', which appeared in the Seventh Edition Bell Labs
+current Unix shell ‘sh’, which appeared in the Seventh Edition Bell Labs
Research version of Unix.
- Bash is largely compatible with 'sh' and incorporates useful features
-from the Korn shell 'ksh' and the C shell 'csh'. It is intended to be a
+ Bash is largely compatible with ‘sh’ and incorporates useful features
+from the Korn shell ‘ksh’ and the C shell ‘csh’. It is intended to be a
conformant implementation of the IEEE POSIX Shell and Tools portion of
the IEEE POSIX specification (IEEE Standard 1003.1). It offers
-functional improvements over 'sh' for both interactive and programming
+functional improvements over ‘sh’ for both interactive and programming
use.
While the GNU operating system provides other shells, including a
-version of 'csh', Bash is the default shell. Like other GNU software,
+version of ‘csh’, Bash is the default shell. Like other GNU software,
Bash is quite portable. It currently runs on nearly every version of
-Unix and a few other operating systems - independently-supported ports
+Unix and a few other operating systems − independently-supported ports
exist for MS-DOS, OS/2, and Windows platforms.
\1f
features allow these utilities to be combined. Files containing
commands can be created, and become commands themselves. These new
commands have the same status as system commands in directories such as
-'/bin', allowing users or groups to establish custom environments to
+‘/bin’, allowing users or groups to establish custom environments to
automate their common tasks.
Shells may be used interactively or non-interactively. In
asynchronously. The shell waits for synchronous commands to complete
before accepting more input; asynchronous commands continue to execute
in parallel with the shell while it reads and executes additional
-commands. The "redirection" constructs permit fine-grained control of
+commands. The “redirection” constructs permit fine-grained control of
the input and output of those commands. Moreover, the shell allows
control over the contents of commands' environments.
- Shells also provide a small set of built-in commands ("builtins")
+ Shells also provide a small set of built-in commands (“builtins”)
implementing functionality impossible or inconvenient to obtain via
-separate utilities. For example, 'cd', 'break', 'continue', and 'exec'
+separate utilities. For example, ‘cd’, ‘break’, ‘continue’, and ‘exec’
cannot be implemented outside of the shell because they directly
-manipulate the shell itself. The 'history', 'getopts', 'kill', or 'pwd'
+manipulate the shell itself. The ‘history’, ‘getopts’, ‘kill’, or ‘pwd’
builtins, among others, could be implemented in separate utilities, but
they are more convenient to use as builtin commands. All of the shell
builtins are described in subsequent sections.
These definitions are used throughout the remainder of this manual.
-'POSIX'
+‘POSIX’
A family of open system standards based on Unix. Bash is primarily
concerned with the Shell and Utilities portion of the POSIX 1003.1
standard.
-'blank'
+‘blank’
A space or tab character.
-'builtin'
+‘builtin’
A command that is implemented internally by the shell itself,
rather than by an executable program somewhere in the file system.
-'control operator'
- A 'token' that performs a control function. It is a 'newline' or
- one of the following: '||', '&&', '&', ';', ';;', ';&', ';;&', '|',
- '|&', '(', or ')'.
+‘control operator’
+ A ‘token’ that performs a control function. It is a ‘newline’ or
+ one of the following: ‘||’, ‘&&’, ‘&’, ‘;’, ‘;;’, ‘;&’, ‘;;&’, ‘|’,
+ ‘|&’, ‘(’, or ‘)’.
-'exit status'
+‘exit status’
The value returned by a command to its caller. The value is
restricted to eight bits, so the maximum value is 255.
-'field'
+‘field’
A unit of text that is the result of one of the shell expansions.
After expansion, when executing a command, the resulting fields are
used as the command name and arguments.
-'filename'
+‘filename’
A string of characters used to identify a file.
-'job'
+‘job’
A set of processes comprising a pipeline, and any processes
descended from it, that are all in the same process group.
-'job control'
+‘job control’
A mechanism by which users can selectively stop (suspend) and
restart (resume) execution of processes.
-'metacharacter'
+‘metacharacter’
A character that, when unquoted, separates words. A metacharacter
- is a 'space', 'tab', 'newline', or one of the following characters:
- '|', '&', ';', '(', ')', '<', or '>'.
+ is a ‘space’, ‘tab’, ‘newline’, or one of the following characters:
+ ‘|’, ‘&’, ‘;’, ‘(’, ‘)’, ‘<’, or ‘>’.
-'name'
- A 'word' consisting solely of letters, numbers, and underscores,
- and beginning with a letter or underscore. 'Name's are used as
+‘name’
+ A ‘word’ consisting solely of letters, numbers, and underscores,
+ and beginning with a letter or underscore. ‘Name’s are used as
shell variable and function names. Also referred to as an
- 'identifier'.
+ ‘identifier’.
-'operator'
- A 'control operator' or a 'redirection operator'. *Note
+‘operator’
+ A ‘control operator’ or a ‘redirection operator’. *Note
Redirections::, for a list of redirection operators. Operators
- contain at least one unquoted 'metacharacter'.
+ contain at least one unquoted ‘metacharacter’.
-'process group'
+‘process group’
A collection of related processes each having the same process
group ID.
-'process group ID'
- A unique identifier that represents a 'process group' during its
+‘process group ID’
+ A unique identifier that represents a ‘process group’ during its
lifetime.
-'reserved word'
- A 'word' that has a special meaning to the shell. Most reserved
- words introduce shell flow control constructs, such as 'for' and
- 'while'.
+‘reserved word’
+ A ‘word’ that has a special meaning to the shell. Most reserved
+ words introduce shell flow control constructs, such as ‘for’ and
+ ‘while’.
-'return status'
- A synonym for 'exit status'.
+‘return status’
+ A synonym for ‘exit status’.
-'signal'
+‘signal’
A mechanism by which a process may be notified by the kernel of an
event occurring in the system.
-'special builtin'
+‘special builtin’
A shell builtin command that has been classified as special by the
POSIX standard.
-'token'
+‘token’
A sequence of characters considered a single unit by the shell. It
- is either a 'word' or an 'operator'.
+ is either a ‘word’ or an ‘operator’.
-'word'
+‘word’
A sequence of characters treated as a unit by the shell. Words may
- not include unquoted 'metacharacters'.
+ not include unquoted ‘metacharacters’.
\1f
File: bash.info, Node: Basic Shell Features, Next: Shell Builtin Commands, Prev: Definitions, Up: Top
3 Basic Shell Features
**********************
-Bash is an acronym for 'Bourne-Again SHell'. The Bourne shell is the
+Bash is an acronym for ‘Bourne-Again SHell’. The Bourne shell is the
traditional Unix shell originally written by Stephen Bourne. All of the
Bourne shell builtin commands are available in Bash, The rules for
evaluation and quoting are taken from the POSIX specification for the
When the shell reads input, it proceeds through a sequence of
operations. If the input indicates the beginning of a comment, the
-shell ignores the comment symbol ('#'), and the rest of that line.
+shell ignores the comment symbol (‘#’), and the rest of that line.
Otherwise, roughly speaking, the shell reads its input and divides
the input into words and operators, employing the quoting rules to
reads and executes a command. Basically, the shell does the following:
1. Reads its input from a file (*note Shell Scripts::), from a string
- supplied as an argument to the '-c' invocation option (*note
+ supplied as an argument to the ‘-c’ invocation option (*note
Invoking Bash::), or from the user's terminal.
2. Breaks the input into words and operators, obeying the quoting
rules described in *note Quoting::. These tokens are separated by
- 'metacharacters'. Alias expansion is performed by this step (*note
+ ‘metacharacters’. Alias expansion is performed by this step (*note
Aliases::).
3. Parses the tokens into simple and compound commands (*note Shell
Each of the shell metacharacters (*note Definitions::) has special
meaning to the shell and must be quoted if it is to represent itself.
When the command history expansion facilities are being used (*note
-History Interaction::), the "history expansion" character, usually '!',
+History Interaction::), the “history expansion” character, usually ‘!’,
must be quoted to prevent history expansion. *Note Bash History
Facilities::, for more details concerning history expansion.
- There are three quoting mechanisms: the "escape character", single
+ There are three quoting mechanisms: the “escape character”, single
quotes, and double quotes.
\1f
3.1.2.1 Escape Character
........................
-A non-quoted backslash '\' is the Bash escape character. It preserves
+A non-quoted backslash ‘\’ is the Bash escape character. It preserves
the literal value of the next character that follows, with the exception
-of 'newline'. If a '\newline' pair appears, and the backslash itself is
-not quoted, the '\newline' is treated as a line continuation (that is,
+of ‘newline’. If a ‘\newline’ pair appears, and the backslash itself is
+not quoted, the ‘\newline’ is treated as a line continuation (that is,
it is removed from the input stream and effectively ignored).
\1f
3.1.2.2 Single Quotes
.....................
-Enclosing characters in single quotes (''') preserves the literal value
+Enclosing characters in single quotes (‘'’) preserves the literal value
of each character within the quotes. A single quote may not occur
between single quotes, even when preceded by a backslash.
3.1.2.3 Double Quotes
.....................
-Enclosing characters in double quotes ('"') preserves the literal value
-of all characters within the quotes, with the exception of '$', '`',
-'\', and, when history expansion is enabled, '!'. When the shell is in
-POSIX mode (*note Bash POSIX Mode::), the '!' has no special meaning
+Enclosing characters in double quotes (‘"’) preserves the literal value
+of all characters within the quotes, with the exception of ‘$’, ‘`’,
+‘\’, and, when history expansion is enabled, ‘!’. When the shell is in
+POSIX mode (*note Bash POSIX Mode::), the ‘!’ has no special meaning
within double quotes, even when history expansion is enabled. The
-characters '$' and '`' retain their special meaning within double quotes
+characters ‘$’ and ‘`’ retain their special meaning within double quotes
(*note Shell Expansions::). The backslash retains its special meaning
-only when followed by one of the following characters: '$', '`', '"',
-'\', or 'newline'. Within double quotes, backslashes that are followed
+only when followed by one of the following characters: ‘$’, ‘`’, ‘"’,
+‘\’, or ‘newline’. Within double quotes, backslashes that are followed
by one of these characters are removed. Backslashes preceding
characters without a special meaning are left unmodified. A double
quote may be quoted within double quotes by preceding it with a
backslash. If enabled, history expansion will be performed unless an
-'!' appearing in double quotes is escaped using a backslash. The
-backslash preceding the '!' is not removed.
+‘!’ appearing in double quotes is escaped using a backslash. The
+backslash preceding the ‘!’ is not removed.
- The special parameters '*' and '@' have special meaning when in
+ The special parameters ‘*’ and ‘@’ have special meaning when in
double quotes (*note Shell Parameter Expansion::).
\1f
3.1.2.4 ANSI-C Quoting
......................
-Character sequences of the form '$'STRING'' are treated as a special
+Character sequences of the form ‘$'STRING'’ are treated as a special
kind of single quotes. The sequence expands to STRING, with
backslash-escaped characters in STRING replaced as specified by the ANSI
C standard. Backslash escape sequences, if present, are decoded as
follows:
-'\a'
+‘\a’
alert (bell)
-'\b'
+‘\b’
backspace
-'\e'
-'\E'
+‘\e’
+‘\E’
an escape character (not ANSI C)
-'\f'
+‘\f’
form feed
-'\n'
+‘\n’
newline
-'\r'
+‘\r’
carriage return
-'\t'
+‘\t’
horizontal tab
-'\v'
+‘\v’
vertical tab
-'\\'
+‘\\’
backslash
-'\''
+‘\'’
single quote
-'\"'
+‘\"’
double quote
-'\?'
+‘\?’
question mark
-'\NNN'
+‘\NNN’
the eight-bit character whose value is the octal value NNN (one to
three octal digits)
-'\xHH'
+‘\xHH’
the eight-bit character whose value is the hexadecimal value HH
(one or two hex digits)
-'\uHHHH'
+‘\uHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHH (one to four hex digits)
-'\UHHHHHHHH'
+‘\UHHHHHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHHHHHH (one to eight hex digits)
-'\cX'
+‘\cX’
a control-X character
The expanded result is single-quoted, as if the dollar sign had not been
* Creating Internationalized Scripts:: How to use translations and different
languages in your scripts.
-Prefixing a double-quoted string with a dollar sign ('$'), such as
+Prefixing a double-quoted string with a dollar sign (‘$’), such as
$"hello, world", will cause the string to be translated according to the
-current locale. The 'gettext' infrastructure performs the lookup and
-translation, using the 'LC_MESSAGES', 'TEXTDOMAINDIR', and 'TEXTDOMAIN'
+current locale. The ‘gettext’ infrastructure performs the lookup and
+translation, using the ‘LC_MESSAGES’, ‘TEXTDOMAINDIR’, and ‘TEXTDOMAIN’
shell variables, as explained below. See the gettext documentation for
-additional details not covered here. If the current locale is 'C' or
-'POSIX', if there are no translations available, of if the string is not
+additional details not covered here. If the current locale is ‘C’ or
+‘POSIX’, if there are no translations available, of if the string is not
translated, the dollar sign is ignored. Since this is a form of double
quoting, the string remains double-quoted by default, whether or not it
-is translated and replaced. If the 'noexpand_translation' option is
-enabled using the 'shopt' builtin (*note The Shopt Builtin::),
+is translated and replaced. If the ‘noexpand_translation’ option is
+enabled using the ‘shopt’ builtin (*note The Shopt Builtin::),
translated strings are single-quoted instead of double-quoted.
The rest of this section is a brief overview of how you use gettext
bash --dump-po-strings SCRIPTNAME > DOMAIN.pot
-The DOMAIN is your "message domain". It's just an arbitrary string
+The DOMAIN is your “message domain”. It's just an arbitrary string
that's used to identify the files gettext needs, like a package or
script name. It needs to be unique among all the message domains on
systems where you install the translations, so gettext knows which
translations correspond to your script. You'll use the template file to
create translations for each target language. The template file
-conventionally has the suffix '.pot'.
+conventionally has the suffix ‘.pot’.
You copy this template file to a separate file for each target
language you want to support (called "PO" files, which use the suffix
-'.po'). PO files use various naming conventions, but when you are
+‘.po’). PO files use various naming conventions, but when you are
working to translate a template file into a particular language, you
first copy the template file to a file whose name is the language you
-want to target, with the '.po' suffix. For instance, the Spanish
-translations of your strings would be in a file named 'es.po', and to
+want to target, with the ‘.po’ suffix. For instance, the Spanish
+translations of your strings would be in a file named ‘es.po’, and to
get started using a message domain named "example," you would run
cp example.pot es.po
gettext tools to produce what are called "MO" files, which are compiled
versions of the PO files the gettext tools use to look up translations
efficiently. MO files are also called "message catalog" files. You use
-the 'msgfmt' program to do this. For instance, if you had a file with
+the ‘msgfmt’ program to do this. For instance, if you had a file with
Spanish translations, you could run
msgfmt -o es.mo es.po
to produce the corresponding MO file.
Once you have the MO files, you decide where to install them and use
-the 'TEXTDOMAINDIR' shell variable to tell the gettext tools where they
+the ‘TEXTDOMAINDIR’ shell variable to tell the gettext tools where they
are. Make sure to use the same message domain to name the MO files as
you did for the PO files when you install them.
- Your users will use the 'LANG' or 'LC_MESSAGES' shell variables to
+ Your users will use the ‘LANG’ or ‘LC_MESSAGES’ shell variables to
select the desired language.
- You set the 'TEXTDOMAIN' variable to the script's message domain. As
+ You set the ‘TEXTDOMAIN’ variable to the script's message domain. As
above, you use the message domain to name your translation files.
- You, or possibly your users, set the 'TEXTDOMAINDIR' variable to the
+ You, or possibly your users, set the ‘TEXTDOMAINDIR’ variable to the
name of a directory where the message catalog files are stored. If you
install the message files into the system's standard message catalog
directory, you don't need to worry about this variable.
The directory where the message catalog files are stored varies
between systems. Some use the message catalog selected by the
-'LC_MESSAGES' shell variable. Others create the name of the message
-catalog from the value of the 'TEXTDOMAIN' shell variable, possibly
-adding the '.mo' suffix. If you use the 'TEXTDOMAIN' variable, you may
-need to set the 'TEXTDOMAINDIR' variable to the location of the message
+‘LC_MESSAGES’ shell variable. Others create the name of the message
+catalog from the value of the ‘TEXTDOMAIN’ shell variable, possibly
+adding the ‘.mo’ suffix. If you use the ‘TEXTDOMAIN’ variable, you may
+need to set the ‘TEXTDOMAINDIR’ variable to the location of the message
catalog files, as above. It's common to use both variables in this
-fashion: '$TEXTDOMAINDIR'/'$LC_MESSAGES'/LC_MESSAGES/'$TEXTDOMAIN'.mo.
+fashion: ‘$TEXTDOMAINDIR’/‘$LC_MESSAGES’/LC_MESSAGES/‘$TEXTDOMAIN’.mo.
If you used that last convention, and you wanted to store the message
catalog files with Spanish (es) and Esperanto (eo) translations into a
When all of this is done, and the message catalog files containing
the compiled translations are installed in the correct location, your
users will be able to see translated strings in any of the supported
-languages by setting the 'LANG' or 'LC_MESSAGES' environment variables
+languages by setting the ‘LANG’ or ‘LC_MESSAGES’ environment variables
before running your script.
\1f
--------------
In a non-interactive shell, or an interactive shell in which the
-'interactive_comments' option to the 'shopt' builtin is enabled (*note
-The Shopt Builtin::), a word beginning with '#' causes that word and all
+‘interactive_comments’ option to the ‘shopt’ builtin is enabled (*note
+The Shopt Builtin::), a word beginning with ‘#’ causes that word and all
remaining characters on that line to be ignored. An interactive shell
-without the 'interactive_comments' option enabled does not allow
-comments. The 'interactive_comments' option is on by default in
+without the ‘interactive_comments’ option enabled does not allow
+comments. The ‘interactive_comments’ option is on by default in
interactive shells. *Note Interactive Shells::, for a description of
what makes a shell interactive.
3.2 Shell Commands
==================
-A simple shell command such as 'echo a b c' consists of the command
+A simple shell command such as ‘echo a b c’ consists of the command
itself followed by arguments, separated by spaces.
More complex shell commands are composed of simple commands arranged
The following words are recognized as reserved when unquoted and the
first word of a command (see below for exceptions):
-'if' 'then' 'elif' 'else' 'fi' 'time'
-'for' 'in' 'until' 'while' 'do' 'done'
-'case' 'esac' 'coproc''select''function'
-'{' '}' '[[' ']]' '!'
+‘if’ ‘then’ ‘elif’ ‘else’ ‘fi’ ‘time’
+‘for’ ‘in’ ‘until’ ‘while’ ‘do’ ‘done’
+‘case’ ‘esac’ ‘coproc’‘select’‘function’
+‘{’ ‘}’ ‘[[’ ‘]]’ ‘!’
-'in' is recognized as a reserved word if it is the third word of a
-'case' or 'select' command. 'in' and 'do' are recognized as reserved
-words if they are the third word in a 'for' command.
+‘in’ is recognized as a reserved word if it is the third word of a
+‘case’ or ‘select’ command. ‘in’ and ‘do’ are recognized as reserved
+words if they are the third word in a ‘for’ command.
\1f
File: bash.info, Node: Simple Commands, Next: Pipelines, Prev: Reserved Words, Up: Shell Commands
---------------------
A simple command is the kind of command encountered most often. It's
-just a sequence of words separated by 'blank's, terminated by one of the
+just a sequence of words separated by ‘blank’s, terminated by one of the
shell's control operators (*note Definitions::). The first word
generally specifies a command to be executed, with the rest of the words
being that command's arguments.
The return status (*note Exit Status::) of a simple command is its
-exit status as provided by the POSIX 1003.1 'waitpid' function, or 128+N
+exit status as provided by the POSIX 1003.1 ‘waitpid’ function, or 128+N
if the command was terminated by signal N.
\1f
3.2.3 Pipelines
---------------
-A 'pipeline' is a sequence of one or more commands separated by one of
-the control operators '|' or '|&'.
+A ‘pipeline’ is a sequence of one or more commands separated by one of
+the control operators ‘|’ or ‘|&’.
The format for a pipeline is
[time [-p]] [!] COMMAND1 [ | or |& COMMAND2 ] ...
command's output. This connection is performed before any redirections
specified by COMMAND1.
- If '|&' is used, COMMAND1's standard error, in addition to its
+ If ‘|&’ is used, COMMAND1's standard error, in addition to its
standard output, is connected to COMMAND2's standard input through the
-pipe; it is shorthand for '2>&1 |'. This implicit redirection of the
+pipe; it is shorthand for ‘2>&1 |’. This implicit redirection of the
standard error to the standard output is performed after any
redirections specified by COMMAND1.
- The reserved word 'time' causes timing statistics to be printed for
+ The reserved word ‘time’ causes timing statistics to be printed for
the pipeline once it finishes. The statistics currently consist of
elapsed (wall-clock) time and user and system time consumed by the
-command's execution. The '-p' option changes the output format to that
+command's execution. The ‘-p’ option changes the output format to that
specified by POSIX. When the shell is in POSIX mode (*note Bash POSIX
-Mode::), it does not recognize 'time' as a reserved word if the next
-token begins with a '-'. The 'TIMEFORMAT' variable may be set to a
+Mode::), it does not recognize ‘time’ as a reserved word if the next
+token begins with a ‘-’. The ‘TIMEFORMAT’ variable may be set to a
format string that specifies how the timing information should be
displayed. *Note Bash Variables::, for a description of the available
-formats. The use of 'time' as a reserved word permits the timing of
-shell builtins, shell functions, and pipelines. An external 'time'
+formats. The use of ‘time’ as a reserved word permits the timing of
+shell builtins, shell functions, and pipelines. An external ‘time’
command cannot time these easily.
- When the shell is in POSIX mode (*note Bash POSIX Mode::), 'time' may
+ When the shell is in POSIX mode (*note Bash POSIX Mode::), ‘time’ may
be followed by a newline. In this case, the shell displays the total
user and system time consumed by the shell and its children. The
-'TIMEFORMAT' variable specifies the format of the time information.
+‘TIMEFORMAT’ variable specifies the format of the time information.
If the pipeline is not executed asynchronously (*note Lists::), the
shell waits for all commands in the pipeline to complete.
Each command in a multi-command pipeline, where pipes are created, is
-executed in its own "subshell", which is a separate process (*note
-Command Execution Environment::). If the 'lastpipe' option is enabled
-using the 'shopt' builtin (*note The Shopt Builtin::), the last element
+executed in its own “subshell”, which is a separate process (*note
+Command Execution Environment::). If the ‘lastpipe’ option is enabled
+using the ‘shopt’ builtin (*note The Shopt Builtin::), the last element
of a pipeline may be run by the shell process when job control is not
active.
The exit status of a pipeline is the exit status of the last command
-in the pipeline, unless the 'pipefail' option is enabled (*note The Set
-Builtin::). If 'pipefail' is enabled, the pipeline's return status is
+in the pipeline, unless the ‘pipefail’ option is enabled (*note The Set
+Builtin::). If ‘pipefail’ is enabled, the pipeline's return status is
the value of the last (rightmost) command to exit with a non-zero
status, or zero if all commands exit successfully. If the reserved word
-'!' precedes the pipeline, the exit status is the logical negation of
+‘!’ precedes the pipeline, the exit status is the logical negation of
the exit status as described above. The shell waits for all commands in
the pipeline to terminate before returning a value.
3.2.4 Lists of Commands
-----------------------
-A 'list' is a sequence of one or more pipelines separated by one of the
-operators ';', '&', '&&', or '||', and optionally terminated by one of
-';', '&', or a 'newline'.
+A ‘list’ is a sequence of one or more pipelines separated by one of the
+operators ‘;’, ‘&’, ‘&&’, or ‘||’, and optionally terminated by one of
+‘;’, ‘&’, or a ‘newline’.
- Of these list operators, '&&' and '||' have equal precedence,
-followed by ';' and '&', which have equal precedence.
+ Of these list operators, ‘&&’ and ‘||’ have equal precedence,
+followed by ‘;’ and ‘&’, which have equal precedence.
- A sequence of one or more newlines may appear in a 'list' to delimit
+ A sequence of one or more newlines may appear in a ‘list’ to delimit
commands, equivalent to a semicolon.
- If a command is terminated by the control operator '&', the shell
+ If a command is terminated by the control operator ‘&’, the shell
executes the command asynchronously in a subshell. This is known as
-executing the command in the "background", and these are referred to as
-"asynchronous" commands. The shell does not wait for the command to
+executing the command in the “background”, and these are referred to as
+“asynchronous” commands. The shell does not wait for the command to
finish, and the return status is 0 (true). When job control is not
active (*note Job Control::), the standard input for asynchronous
commands, in the absence of any explicit redirections, is redirected
-from '/dev/null'.
+from ‘/dev/null’.
- Commands separated by a ';' are executed sequentially; the shell
+ Commands separated by a ‘;’ are executed sequentially; the shell
waits for each command to terminate in turn. The return status is the
exit status of the last command executed.
AND and OR lists are sequences of one or more pipelines separated by
-the control operators '&&' and '||', respectively. AND and OR lists are
+the control operators ‘&&’ and ‘||’, respectively. AND and OR lists are
executed with left associativity.
An AND list has the form
Bash supports the following looping constructs.
- Note that wherever a ';' appears in the description of a command's
+ Note that wherever a ‘;’ appears in the description of a command's
syntax, it may be replaced with one or more newlines.
-'until'
- The syntax of the 'until' command is:
+‘until’
+ The syntax of the ‘until’ command is:
until TEST-COMMANDS; do CONSEQUENT-COMMANDS; done
the last command executed in CONSEQUENT-COMMANDS, or zero if none
was executed.
-'while'
- The syntax of the 'while' command is:
+‘while’
+ The syntax of the ‘while’ command is:
while TEST-COMMANDS; do CONSEQUENT-COMMANDS; done
command executed in CONSEQUENT-COMMANDS, or zero if none was
executed.
-'for'
- The syntax of the 'for' command is:
+‘for’
+ The syntax of the ‘for’ command is:
for NAME [ [in [WORDS ...] ] ; ] do COMMANDS; done
Expand WORDS (*note Shell Expansions::), and execute COMMANDS once
for each member in the resultant list, with NAME bound to the
- current member. If 'in WORDS' is not present, the 'for' command
+ current member. If ‘in WORDS’ is not present, the ‘for’ command
executes the COMMANDS once for each positional parameter that is
- set, as if 'in "$@"' had been specified (*note Special
+ set, as if ‘in "$@"’ had been specified (*note Special
Parameters::).
The return status is the exit status of the last command that
executes. If there are no items in the expansion of WORDS, no
commands are executed, and the return status is zero.
- An alternate form of the 'for' command is also supported:
+ An alternate form of the ‘for’ command is also supported:
for (( EXPR1 ; EXPR2 ; EXPR3 )) ; do COMMANDS ; done
command in COMMANDS that is executed, or false if any of the
expressions is invalid.
- The 'break' and 'continue' builtins (*note Bourne Shell Builtins::)
+ The ‘break’ and ‘continue’ builtins (*note Bourne Shell Builtins::)
may be used to control loop execution.
\1f
3.2.5.2 Conditional Constructs
..............................
-'if'
- The syntax of the 'if' command is:
+‘if’
+ The syntax of the ‘if’ command is:
if TEST-COMMANDS; then
CONSEQUENT-COMMANDS;
The TEST-COMMANDS list is executed, and if its return status is
zero, the CONSEQUENT-COMMANDS list is executed. If TEST-COMMANDS
- returns a non-zero status, each 'elif' list is executed in turn,
+ returns a non-zero status, each ‘elif’ list is executed in turn,
and if its exit status is zero, the corresponding MORE-CONSEQUENTS
- is executed and the command completes. If 'else
- ALTERNATE-CONSEQUENTS' is present, and the final command in the
- final 'if' or 'elif' clause has a non-zero exit status, then
+ is executed and the command completes. If ‘else
+ ALTERNATE-CONSEQUENTS’ is present, and the final command in the
+ final ‘if’ or ‘elif’ clause has a non-zero exit status, then
ALTERNATE-CONSEQUENTS is executed. The return status is the exit
status of the last command executed, or zero if no condition tested
true.
-'case'
- The syntax of the 'case' command is:
+‘case’
+ The syntax of the ‘case’ command is:
case WORD in
[ [(] PATTERN [| PATTERN]...) COMMAND-LIST ;;]...
esac
- 'case' will selectively execute the COMMAND-LIST corresponding to
+ ‘case’ will selectively execute the COMMAND-LIST corresponding to
the first PATTERN that matches WORD. The match is performed
according to the rules described below in *note Pattern Matching::.
- If the 'nocasematch' shell option (see the description of 'shopt'
+ If the ‘nocasematch’ shell option (see the description of ‘shopt’
in *note The Shopt Builtin::) is enabled, the match is performed
- without regard to the case of alphabetic characters. The '|' is
- used to separate multiple patterns, and the ')' operator terminates
+ without regard to the case of alphabetic characters. The ‘|’ is
+ used to separate multiple patterns, and the ‘)’ operator terminates
a pattern list. A list of patterns and an associated command-list
is known as a CLAUSE.
- Each clause must be terminated with ';;', ';&', or ';;&'. The WORD
+ Each clause must be terminated with ‘;;’, ‘;&’, or ‘;;&’. The WORD
undergoes tilde expansion, parameter expansion, command
substitution, arithmetic expansion, and quote removal (*note Shell
Parameter Expansion::) before matching is attempted. Each PATTERN
substitution, arithmetic expansion, process substitution, and quote
removal.
- There may be an arbitrary number of 'case' clauses, each terminated
- by a ';;', ';&', or ';;&'. The first pattern that matches
+ There may be an arbitrary number of ‘case’ clauses, each terminated
+ by a ‘;;’, ‘;&’, or ‘;;&’. The first pattern that matches
determines the command-list that is executed. It's a common idiom
- to use '*' as the final pattern to define the default case, since
+ to use ‘*’ as the final pattern to define the default case, since
that pattern will always match.
- Here is an example using 'case' in a script that could be used to
+ Here is an example using ‘case’ in a script that could be used to
describe one interesting feature of an animal:
echo -n "Enter the name of an animal: "
esac
echo " legs."
-
- If the ';;' operator is used, no subsequent matches are attempted
- after the first pattern match. Using ';&' in place of ';;' causes
+ If the ‘;;’ operator is used, no subsequent matches are attempted
+ after the first pattern match. Using ‘;&’ in place of ‘;;’ causes
execution to continue with the COMMAND-LIST associated with the
- next clause, if any. Using ';;&' in place of ';;' causes the shell
+ next clause, if any. Using ‘;;&’ in place of ‘;;’ causes the shell
to test the patterns in the next clause, if any, and execute any
associated COMMAND-LIST on a successful match, continuing the case
statement execution as if the pattern list had not matched.
The return status is zero if no PATTERN is matched. Otherwise, the
return status is the exit status of the COMMAND-LIST executed.
-'select'
+‘select’
- The 'select' construct allows the easy generation of menus. It has
- almost the same syntax as the 'for' command:
+ The ‘select’ construct allows the easy generation of menus. It has
+ almost the same syntax as the ‘for’ command:
select NAME [in WORDS ...]; do COMMANDS; done
- The list of words following 'in' is expanded, generating a list of
+ The list of words following ‘in’ is expanded, generating a list of
items, and the set of expanded words is printed on the standard
- error output stream, each preceded by a number. If the 'in WORDS'
- is omitted, the positional parameters are printed, as if 'in "$@"'
- had been specified. 'select' then displays the 'PS3' prompt and
+ error output stream, each preceded by a number. If the ‘in WORDS’
+ is omitted, the positional parameters are printed, as if ‘in "$@"’
+ had been specified. ‘select’ then displays the ‘PS3’ prompt and
reads a line from the standard input. If the line consists of a
number corresponding to one of the displayed words, then the value
of NAME is set to that word. If the line is empty, the words and
- prompt are displayed again. If 'EOF' is read, the 'select' command
+ prompt are displayed again. If ‘EOF’ is read, the ‘select’ command
completes and returns 1. Any other value read causes NAME to be
- set to null. The line read is saved in the variable 'REPLY'.
+ set to null. The line read is saved in the variable ‘REPLY’.
- The COMMANDS are executed after each selection until a 'break'
- command is executed, at which point the 'select' command completes.
+ The COMMANDS are executed after each selection until a ‘break’
+ command is executed, at which point the ‘select’ command completes.
Here is an example that allows the user to pick a filename from the
current directory, and displays the name and index of the file
break;
done
-'((...))'
+‘((...))’
(( EXPRESSION ))
The arithmetic EXPRESSION is evaluated according to the rules
are removed. If the value of the expression is non-zero, the
return status is 0; otherwise the return status is 1.
-'[[...]]'
+‘[[...]]’
[[ EXPRESSION ]]
Return a status of 0 or 1 depending on the evaluation of the
conditional expression EXPRESSION. Expressions are composed of the
primaries described below in *note Bash Conditional Expressions::.
- The words between the '[[' and ']]' do not undergo word splitting
+ The words between the ‘[[’ and ‘]]’ do not undergo word splitting
and filename expansion. The shell performs tilde expansion,
parameter and variable expansion, arithmetic expansion, command
substitution, process substitution, and quote removal on those
words (the expansions that would occur if the words were enclosed
- in double quotes). Conditional operators such as '-f' must be
+ in double quotes). Conditional operators such as ‘-f’ must be
unquoted to be recognized as primaries.
- When used with '[[', the '<' and '>' operators sort
+ When used with ‘[[’, the ‘<’ and ‘>’ operators sort
lexicographically using the current locale.
- When the '==' and '!=' operators are used, the string to the right
+ When the ‘==’ and ‘!=’ operators are used, the string to the right
of the operator is considered a pattern and matched according to
the rules described below in *note Pattern Matching::, as if the
- 'extglob' shell option were enabled. The '=' operator is identical
- to '=='. If the 'nocasematch' shell option (see the description of
- 'shopt' in *note The Shopt Builtin::) is enabled, the match is
+ ‘extglob’ shell option were enabled. The ‘=’ operator is identical
+ to ‘==’. If the ‘nocasematch’ shell option (see the description of
+ ‘shopt’ in *note The Shopt Builtin::) is enabled, the match is
performed without regard to the case of alphabetic characters. The
- return value is 0 if the string matches ('==') or does not match
- ('!=') the pattern, and 1 otherwise.
+ return value is 0 if the string matches (‘==’) or does not match
+ (‘!=’) the pattern, and 1 otherwise.
If you quote any part of the pattern, using any of the shell's
quoting mechanisms, the quoted portion is matched literally. This
means every character in the quoted portion matches itself, instead
of having any special pattern matching meaning.
- An additional binary operator, '=~', is available, with the same
- precedence as '==' and '!='. When you use '=~', the string to the
+ An additional binary operator, ‘=~’, is available, with the same
+ precedence as ‘==’ and ‘!=’. When you use ‘=~’, the string to the
right of the operator is considered a POSIX extended regular
expression pattern and matched accordingly (using the POSIX
- 'regcomp' and 'regexec' interfaces usually described in regex(3)).
+ ‘regcomp’ and ‘regexec’ interfaces usually described in regex(3)).
The return value is 0 if the string matches the pattern, and 1 if
it does not. If the regular expression is syntactically incorrect,
- the conditional expression returns 2. If the 'nocasematch' shell
- option (see the description of 'shopt' in *note The Shopt
+ the conditional expression returns 2. If the ‘nocasematch’ shell
+ option (see the description of ‘shopt’ in *note The Shopt
Builtin::) is enabled, the match is performed without regard to the
case of alphabetic characters.
The pattern will match if it matches any part of the string. If
you want to force the pattern to match the entire string, anchor
- the pattern using the '^' and '$' regular expression operators.
+ the pattern using the ‘^’ and ‘$’ regular expression operators.
For example, the following will match a line (stored in the shell
- variable 'line') if there is a sequence of characters anywhere in
+ variable ‘line’) if there is a sequence of characters anywhere in
the value consisting of any number, including zero, of characters
- in the 'space' character class, immediately followed by zero or one
- instances of 'a', then a 'b':
+ in the ‘space’ character class, immediately followed by zero or one
+ instances of ‘a’, then a ‘b’:
[[ $line =~ [[:space:]]*(a)?b ]]
- That means values for 'line' like 'aab', ' aaaaaab', 'xaby', and '
- ab' will all match, as will a line containing a 'b' anywhere in its
+ That means values for ‘line’ like ‘aab’, ‘ aaaaaab’, ‘xaby’, and ‘
+ ab’ will all match, as will a line containing a ‘b’ anywhere in its
value.
If you want to match a character that's special to the regular
- expression grammar ('^$|[]()\.*+?'), it has to be quoted to remove
- its special meaning. This means that in the pattern 'xxx.txt', the
- '.' matches any character in the string (its usual regular
- expression meaning), but in the pattern '"xxx.txt"', it can only
- match a literal '.'.
+ expression grammar (‘^$|[]()\.*+?’), it has to be quoted to remove
+ its special meaning. This means that in the pattern ‘xxx.txt’, the
+ ‘.’ matches any character in the string (its usual regular
+ expression meaning), but in the pattern ‘"xxx.txt"’, it can only
+ match a literal ‘.’.
Likewise, if you want to include a character in your pattern that
has a special meaning to the regular expression grammar, you must
make sure it's not quoted. If you want to anchor a pattern at the
beginning or end of the string, for instance, you cannot quote the
- '^' or '$' characters using any form of shell quoting.
+ ‘^’ or ‘$’ characters using any form of shell quoting.
- If you want to match 'initial string' at the start of a line, the
+ If you want to match ‘initial string’ at the start of a line, the
following will work:
[[ $line =~ ^"initial string" ]]
but this will not:
[[ $line =~ "^initial string" ]]
- because in the second example the '^' is quoted and doesn't have
+ because in the second example the ‘^’ is quoted and doesn't have
its usual special meaning.
It is sometimes difficult to specify a regular expression properly
The first two matches will succeed, but the second two will not,
because in the second two the backslash will be part of the pattern
to be matched. In the first two examples, the pattern passed to
- the regular expression parser is '\.'. The backslash removes the
- special meaning from '.', so the literal '.' matches. In the
+ the regular expression parser is ‘\.’. The backslash removes the
+ special meaning from ‘.’, so the literal ‘.’ matches. In the
second two examples, the pattern passed to the regular expression
- parser has the backslash quoted (e.g., '\\\.'), which will not
+ parser has the backslash quoted (e.g., ‘\\\.’), which will not
match the string, since it does not contain a backslash. If the
- string in the first examples were anything other than '.', say 'a',
- the pattern would not match, because the quoted '.' in the pattern
+ string in the first examples were anything other than ‘.’, say ‘a’,
+ the pattern would not match, because the quoted ‘.’ in the pattern
loses its special meaning of matching any single character.
Bracket expressions in regular expressions can be sources of errors
purpose.
Though it might seem like a strange way to write it, the following
- pattern will match a '.' in the string:
+ pattern will match a ‘.’ in the string:
[[ . =~ [.] ]]
twice as much as possible, so shell quoting should be sufficient to
quote special pattern characters where that's necessary.
- The array variable 'BASH_REMATCH' records which parts of the string
- matched the pattern. The element of 'BASH_REMATCH' with index 0
+ The array variable ‘BASH_REMATCH’ records which parts of the string
+ matched the pattern. The element of ‘BASH_REMATCH’ with index 0
contains the portion of the string matching the entire regular
expression. Substrings matched by parenthesized subexpressions
within the regular expression are saved in the remaining
- 'BASH_REMATCH' indices. The element of 'BASH_REMATCH' with index N
+ ‘BASH_REMATCH’ indices. The element of ‘BASH_REMATCH’ with index N
is the portion of the string matching the Nth parenthesized
subexpression.
- Bash sets 'BASH_REMATCH' in the global scope; declaring it as a
+ Bash sets ‘BASH_REMATCH’ in the global scope; declaring it as a
local variable will lead to unexpected results.
Expressions may be combined using the following operators, listed
in decreasing order of precedence:
- '( EXPRESSION )'
+ ‘( EXPRESSION )’
Returns the value of EXPRESSION. This may be used to override
the normal precedence of operators.
- '! EXPRESSION'
+ ‘! EXPRESSION’
True if EXPRESSION is false.
- 'EXPRESSION1 && EXPRESSION2'
+ ‘EXPRESSION1 && EXPRESSION2’
True if both EXPRESSION1 and EXPRESSION2 are true.
- 'EXPRESSION1 || EXPRESSION2'
+ ‘EXPRESSION1 || EXPRESSION2’
True if either EXPRESSION1 or EXPRESSION2 is true.
- The '&&' and '||' operators do not evaluate EXPRESSION2 if the
+ The ‘&&’ and ‘||’ operators do not evaluate EXPRESSION2 if the
value of EXPRESSION1 is sufficient to determine the return value of
the entire conditional expression.
entire command list. For example, the output of all the commands in the
list may be redirected to a single stream.
-'()'
+‘()’
( LIST )
Placing a list of commands between parentheses forces the shell to
Since the LIST is executed in a subshell, variable assignments do
not remain in effect after the subshell completes.
-'{}'
+‘{}’
{ LIST; }
Placing a list of commands between curly braces causes the list to
In addition to the creation of a subshell, there is a subtle
difference between these two constructs due to historical reasons. The
braces are reserved words, so they must be separated from the LIST by
-'blank's or other shell metacharacters. The parentheses are operators,
+‘blank’s or other shell metacharacters. The parentheses are operators,
and are recognized as separate tokens by the shell even if they are not
separated from the LIST by whitespace.
3.2.6 Coprocesses
-----------------
-A 'coprocess' is a shell command preceded by the 'coproc' reserved word.
+A ‘coprocess’ is a shell command preceded by the ‘coproc’ reserved word.
A coprocess is executed asynchronously in a subshell, as if the command
-had been terminated with the '&' control operator, with a two-way pipe
+had been terminated with the ‘&’ control operator, with a two-way pipe
established between the executing shell and the coprocess.
The syntax for a coprocess is:
This creates a coprocess named NAME. COMMAND may be either a simple
command (*note Simple Commands::) or a compound command (*note Compound
Commands::). NAME is a shell variable name. If NAME is not supplied,
-the default name is 'COPROC'.
+the default name is ‘COPROC’.
The recommended form to use for a coprocess is
coproc NAME { COMMAND; }
This form is recommended because simple commands result in the coprocess
-always being named 'COPROC', and it is simpler to use and more complete
+always being named ‘COPROC’, and it is simpler to use and more complete
than the other compound commands.
There are other forms of coprocesses:
coproc SIMPLE-COMMAND
If COMMAND is a compound command, NAME is optional. The word following
-'coproc' determines whether that word is interpreted as a variable name:
+‘coproc’ determines whether that word is interpreted as a variable name:
it is interpreted as NAME if it is not a reserved word that introduces a
compound command. If COMMAND is a simple command, NAME is not allowed;
this is to avoid confusion between NAME and the first word of the simple
subshells.
The process ID of the shell spawned to execute the coprocess is
-available as the value of the variable 'NAME_PID'. The 'wait' builtin
+available as the value of the variable ‘NAME_PID’. The ‘wait’ builtin
command may be used to wait for the coprocess to terminate.
Since the coprocess is created as an asynchronous command, the
-'coproc' command always returns success. The return status of a
+‘coproc’ command always returns success. The return status of a
coprocess is the exit status of COMMAND.
\1f
read from files. GNU Parallel provides shorthand references to many of
the most common operations (input lines, various portions of the input
line, different ways to specify the input source, and so on). Parallel
-can replace 'xargs' or feed commands from its input sources to several
+can replace ‘xargs’ or feed commands from its input sources to several
different instances of Bash.
For a complete description, refer to the GNU Parallel documentation,
function FNAME [()] COMPOUND-COMMAND [ REDIRECTIONS ]
This defines a shell function named FNAME. The reserved word
-'function' is optional. If the 'function' reserved word is supplied,
-the parentheses are optional. The "body" of the function is the
+‘function’ is optional. If the ‘function’ reserved word is supplied,
+the parentheses are optional. The “body” of the function is the
compound command COMPOUND-COMMAND (*note Compound Commands::). That
command is usually a LIST enclosed between { and }, but may be any
-compound command listed above. If the 'function' reserved word is used,
+compound command listed above. If the ‘function’ reserved word is used,
but the parentheses are not supplied, the braces are recommended.
COMPOUND-COMMAND is executed whenever FNAME is specified as the name of
a simple command. When the shell is in POSIX mode (*note Bash POSIX
Mode::), FNAME must be a valid shell name and may not be the same as one
of the special builtins (*note Special Builtins::). In default mode, a
-function name can be any unquoted shell word that does not contain '$'.
+function name can be any unquoted shell word that does not contain ‘$’.
Any redirections (*note Redirections::) associated with the shell
function are performed when the function is executed. A function
-definition may be deleted using the '-f' option to the 'unset' builtin
+definition may be deleted using the ‘-f’ option to the ‘unset’ builtin
(*note Bourne Shell Builtins::).
The exit status of a function definition is zero unless a syntax
Note that for historical reasons, in the most common usage the curly
braces that surround the body of the function must be separated from the
-body by 'blank's or newlines. This is because the braces are reserved
+body by ‘blank’s or newlines. This is because the braces are reserved
words and are only recognized as such when they are separated from the
command list by whitespace or another shell metacharacter. Also, when
-using the braces, the LIST must be terminated by a semicolon, a '&', or
+using the braces, the LIST must be terminated by a semicolon, a ‘&’, or
a newline.
When a function is executed, the arguments to the function become the
positional parameters during its execution (*note Positional
-Parameters::). The special parameter '#' that expands to the number of
+Parameters::). The special parameter ‘#’ that expands to the number of
positional parameters is updated to reflect the change. Special
-parameter '0' is unchanged. The first element of the 'FUNCNAME'
+parameter ‘0’ is unchanged. The first element of the ‘FUNCNAME’
variable is set to the name of the function while the function is
executing.
All other aspects of the shell execution environment are identical
-between a function and its caller with these exceptions: the 'DEBUG' and
-'RETURN' traps are not inherited unless the function has been given the
-'trace' attribute using the 'declare' builtin or the '-o functrace'
-option has been enabled with the 'set' builtin, (in which case all
-functions inherit the 'DEBUG' and 'RETURN' traps), and the 'ERR' trap is
-not inherited unless the '-o errtrace' shell option has been enabled.
-*Note Bourne Shell Builtins::, for the description of the 'trap'
+between a function and its caller with these exceptions: the ‘DEBUG’ and
+‘RETURN’ traps are not inherited unless the function has been given the
+‘trace’ attribute using the ‘declare’ builtin or the ‘-o functrace’
+option has been enabled with the ‘set’ builtin, (in which case all
+functions inherit the ‘DEBUG’ and ‘RETURN’ traps), and the ‘ERR’ trap is
+not inherited unless the ‘-o errtrace’ shell option has been enabled.
+*Note Bourne Shell Builtins::, for the description of the ‘trap’
builtin.
- The 'FUNCNEST' variable, if set to a numeric value greater than 0,
+ The ‘FUNCNEST’ variable, if set to a numeric value greater than 0,
defines a maximum function nesting level. Function invocations that
exceed the limit cause the entire command to abort.
- If the builtin command 'return' is executed in a function, the
+ If the builtin command ‘return’ is executed in a function, the
function completes and execution resumes with the next command after the
-function call. Any command associated with the 'RETURN' trap is
+function call. Any command associated with the ‘RETURN’ trap is
executed before execution resumes. When a function completes, the
-values of the positional parameters and the special parameter '#' are
+values of the positional parameters and the special parameter ‘#’ are
restored to the values they had prior to the function's execution. If a
-numeric argument is given to 'return', that is the function's return
+numeric argument is given to ‘return’, that is the function's return
status; otherwise the function's return status is the exit status of the
-last command executed before the 'return'.
+last command executed before the ‘return’.
- Variables local to the function may be declared with the 'local'
-builtin ("local variables"). Ordinarily, variables and their values are
+ Variables local to the function may be declared with the ‘local’
+builtin (“local variables”). Ordinarily, variables and their values are
shared between a function and its caller. These variables are visible
only to the function and the commands it invokes. This is particularly
important when a shell function calls other functions.
- In the following description, the "current scope" is a currently-
+ In the following description, the “current scope” is a currently-
executing function. Previous scopes consist of that function's caller
and so on, back to the "global" scope, where the shell is not executing
any shell function. Consequently, a local variable at the current local
-scope is a variable declared using the 'local' or 'declare' builtins in
+scope is a variable declared using the ‘local’ or ‘declare’ builtins in
the function that is currently executing.
Local variables "shadow" variables with the same name declared at
refer to the local variable, leaving the global variable unmodified.
When the function returns, the global variable is once again visible.
- The shell uses "dynamic scoping" to control a variable's visibility
+ The shell uses “dynamic scoping” to control a variable's visibility
within functions. With dynamic scoping, visible variables and their
values are a result of the sequence of function calls that caused
execution to reach the current function. The value of a variable that a
function sees depends on its value within its caller, if any, whether
-that caller is the "global" scope or another shell function. This is
-also the value that a local variable declaration "shadows", and the
-value that is restored when the function returns.
+that caller is the global scope or another shell function. This is also
+the value that a local variable declaration shadows, and the value that
+is restored when the function returns.
- For example, if a variable 'var' is declared as local in function
-'func1', and 'func1' calls another function 'func2', references to 'var'
-made from within 'func2' will resolve to the local variable 'var' from
-'func1', shadowing any global variable named 'var'.
+ For example, if a variable ‘var’ is declared as local in function
+‘func1’, and ‘func1’ calls another function ‘func2’, references to ‘var’
+made from within ‘func2’ will resolve to the local variable ‘var’ from
+‘func1’, shadowing any global variable named ‘var’.
The following script demonstrates this behavior. When executed, the
script displays
var=global
func1
- The 'unset' builtin also acts using the same dynamic scope: if a
-variable is local to the current scope, 'unset' will unset it; otherwise
+ The ‘unset’ builtin also acts using the same dynamic scope: if a
+variable is local to the current scope, ‘unset’ will unset it; otherwise
the unset will refer to the variable found in any calling scope as
described above. If a variable at the current local scope is unset, it
will remain so (appearing as unset) until it is reset in that scope or
the variable at a previous scope will become visible. If the unset acts
on a variable at a previous scope, any instance of a variable with that
name that had been shadowed will become visible (see below how
-'localvar_unset'shell option changes this behavior).
+‘localvar_unset’shell option changes this behavior).
- Function names and definitions may be listed with the '-f' option to
-the 'declare' ('typeset') builtin command (*note Bash Builtins::). The
-'-F' option to 'declare' or 'typeset' will list the function names only
-(and optionally the source file and line number, if the 'extdebug' shell
+ Function names and definitions may be listed with the ‘-f’ option to
+the ‘declare’ (‘typeset’) builtin command (*note Bash Builtins::). The
+‘-F’ option to ‘declare’ or ‘typeset’ will list the function names only
+(and optionally the source file and line number, if the ‘extdebug’ shell
option is enabled). Functions may be exported so that child shell
processes (those created when executing a separate shell invocation)
-automatically have them defined with the '-f' option to the 'export'
+automatically have them defined with the ‘-f’ option to the ‘export’
builtin (*note Bourne Shell Builtins::).
- Functions may be recursive. The 'FUNCNEST' variable may be used to
+ Functions may be recursive. The ‘FUNCNEST’ variable may be used to
limit the depth of the function call stack and restrict the number of
function invocations. By default, no limit is placed on the number of
recursive calls.
* Positional Parameters:: The shell's command-line arguments.
* Special Parameters:: Parameters denoted by special characters.
-A "parameter" is an entity that stores values. It can be a 'name', a
-number, or one of the special characters listed below. A "variable" is
-a parameter denoted by a 'name'. A variable has a 'value' and zero or
-more 'attributes'. Attributes are assigned using the 'declare' builtin
-command (see the description of the 'declare' builtin in *note Bash
+A “parameter” is an entity that stores values. It can be a ‘name’, a
+number, or one of the special characters listed below. A “variable” is
+a parameter denoted by a ‘name’. A variable has a ‘value’ and zero or
+more ‘attributes’. Attributes are assigned using the ‘declare’ builtin
+command (see the description of the ‘declare’ builtin in *note Bash
Builtins::).
A parameter is set if it has been assigned a value. The null string
is a valid value. Once a variable is set, it may be unset only by using
-the 'unset' builtin command.
+the ‘unset’ builtin command.
A variable may be assigned to by a statement of the form
NAME=[VALUE]
If VALUE is not given, the variable is assigned the null string. All
VALUEs undergo tilde expansion, parameter and variable expansion,
command substitution, arithmetic expansion, and quote removal (*note
-Shell Parameter Expansion::). If the variable has its 'integer'
+Shell Parameter Expansion::). If the variable has its ‘integer’
attribute set, then VALUE is evaluated as an arithmetic expression even
-if the '$((...))' expansion is not used (*note Arithmetic Expansion::).
+if the ‘$((...))’ expansion is not used (*note Arithmetic Expansion::).
Word splitting and filename expansion are not performed. Assignment
-statements may also appear as arguments to the 'alias', 'declare',
-'typeset', 'export', 'readonly', and 'local' builtin commands
-("declaration" commands). When in POSIX mode (*note Bash POSIX Mode::),
+statements may also appear as arguments to the ‘alias’, ‘declare’,
+‘typeset’, ‘export’, ‘readonly’, and ‘local’ builtin commands
+(“declaration” commands). When in POSIX mode (*note Bash POSIX Mode::),
these builtins may appear in a command after one or more instances of
-the 'command' builtin and retain these assignment statement properties.
+the ‘command’ builtin and retain these assignment statement properties.
In the context where an assignment statement is assigning a value to
-a shell variable or array index (*note Arrays::), the '+=' operator can
+a shell variable or array index (*note Arrays::), the ‘+=’ operator can
be used to append to or add to the variable's previous value. This
-includes arguments to builtin commands such as 'declare' that accept
-assignment statements (declaration commands). When '+=' is applied to a
-variable for which the 'integer' attribute has been set, VALUE is
+includes arguments to builtin commands such as ‘declare’ that accept
+assignment statements (declaration commands). When ‘+=’ is applied to a
+variable for which the ‘integer’ attribute has been set, VALUE is
evaluated as an arithmetic expression and added to the variable's
-current value, which is also evaluated. When '+=' is applied to an
+current value, which is also evaluated. When ‘+=’ is applied to an
array variable using compound assignment (*note Arrays::), the
-variable's value is not unset (as it is when using '='), and new values
+variable's value is not unset (as it is when using ‘=’), and new values
are appended to the array beginning at one greater than the array's
maximum index (for indexed arrays), or added as additional key-value
pairs in an associative array. When applied to a string-valued
variable, VALUE is expanded and appended to the variable's value.
- A variable can be assigned the 'nameref' attribute using the '-n'
-option to the 'declare' or 'local' builtin commands (*note Bash
-Builtins::) to create a "nameref", or a reference to another variable.
+ A variable can be assigned the ‘nameref’ attribute using the ‘-n’
+option to the ‘declare’ or ‘local’ builtin commands (*note Bash
+Builtins::) to create a “nameref”, or a reference to another variable.
This allows variables to be manipulated indirectly. Whenever the
nameref variable is referenced, assigned to, unset, or has its
attributes modified (other than using or changing the nameref attribute
argument to the function. For instance, if a variable name is passed to
a shell function as its first argument, running
declare -n ref=$1
-inside the function creates a nameref variable 'ref' whose value is the
+inside the function creates a nameref variable ‘ref’ whose value is the
variable name passed as the first argument. References and assignments
-to 'ref', and changes to its attributes, are treated as references,
+to ‘ref’, and changes to its attributes, are treated as references,
assignments, and attribute modifications to the variable whose name was
-passed as '$1'.
+passed as ‘$1’.
- If the control variable in a 'for' loop has the nameref attribute,
+ If the control variable in a ‘for’ loop has the nameref attribute,
the list of words can be a list of shell variables, and a name reference
will be established for each word in the list, in turn, when the loop is
executed. Array variables cannot be given the nameref attribute.
However, nameref variables can reference array variables and subscripted
-array variables. Namerefs can be unset using the '-n' option to the
-'unset' builtin (*note Bourne Shell Builtins::). Otherwise, if 'unset'
+array variables. Namerefs can be unset using the ‘-n’ option to the
+‘unset’ builtin (*note Bourne Shell Builtins::). Otherwise, if ‘unset’
is executed with the name of a nameref variable as an argument, the
variable referenced by the nameref variable will be unset.
3.4.1 Positional Parameters
---------------------------
-A "positional parameter" is a parameter denoted by one or more digits,
-other than the single digit '0'. Positional parameters are assigned
+A “positional parameter” is a parameter denoted by one or more digits,
+other than the single digit ‘0’. Positional parameters are assigned
from the shell's arguments when it is invoked, and may be reassigned
-using the 'set' builtin command. Positional parameter 'N' may be
-referenced as '${N}', or as '$N' when 'N' consists of a single digit.
+using the ‘set’ builtin command. Positional parameter ‘N’ may be
+referenced as ‘${N}’, or as ‘$N’ when ‘N’ consists of a single digit.
Positional parameters may not be assigned to with assignment statements.
-The 'set' and 'shift' builtins are used to set and unset them (*note
+The ‘set’ and ‘shift’ builtins are used to set and unset them (*note
Shell Builtin Commands::). The positional parameters are temporarily
replaced when a shell function is executed (*note Shell Functions::).
The shell treats several parameters specially. These parameters may
only be referenced; assignment to them is not allowed.
-'*'
+‘*’
($*) Expands to the positional parameters, starting from one. When
the expansion is not within double quotes, each positional
parameter expands to a separate word. In contexts where it is
performed, those words are subject to further word splitting and
filename expansion. When the expansion occurs within double
quotes, it expands to a single word with the value of each
- parameter separated by the first character of the 'IFS' special
- variable. That is, '"$*"' is equivalent to '"$1C$2C..."', where C
- is the first character of the value of the 'IFS' variable. If
- 'IFS' is unset, the parameters are separated by spaces. If 'IFS'
+ parameter separated by the first character of the ‘IFS’ special
+ variable. That is, ‘"$*"’ is equivalent to ‘"$1C$2C..."’, where C
+ is the first character of the value of the ‘IFS’ variable. If
+ ‘IFS’ is unset, the parameters are separated by spaces. If ‘IFS’
is null, the parameters are joined without intervening separators.
-'@'
+‘@’
($@) Expands to the positional parameters, starting from one. In
contexts where word splitting is performed, this expands each
positional parameter to a separate word; if not within double
word with each positional parameter separated by a space. When the
expansion occurs within double quotes, and word splitting is
performed, each parameter expands to a separate word. That is,
- '"$@"' is equivalent to '"$1" "$2" ...'. If the double-quoted
+ ‘"$@"’ is equivalent to ‘"$1" "$2" ...’. If the double-quoted
expansion occurs within a word, the expansion of the first
parameter is joined with the beginning part of the original word,
and the expansion of the last parameter is joined with the last
part of the original word. When there are no positional
- parameters, '"$@"' and '$@' expand to nothing (i.e., they are
+ parameters, ‘"$@"’ and ‘$@’ expand to nothing (i.e., they are
removed).
-'#'
+‘#’
($#) Expands to the number of positional parameters in decimal.
-'?'
+‘?’
($?) Expands to the exit status of the most recently executed
foreground pipeline.
-'-'
+‘-’
($-, a hyphen.) Expands to the current option flags as specified
- upon invocation, by the 'set' builtin command, or those set by the
- shell itself (such as the '-i' option).
+ upon invocation, by the ‘set’ builtin command, or those set by the
+ shell itself (such as the ‘-i’ option).
-'$'
+‘$’
($$) Expands to the process ID of the shell. In a subshell, it
expands to the process ID of the invoking shell, not the subshell.
-'!'
+‘!’
($!) Expands to the process ID of the job most recently placed
into the background, whether executed as an asynchronous command or
- using the 'bg' builtin (*note Job Control Builtins::).
+ using the ‘bg’ builtin (*note Job Control Builtins::).
-'0'
+‘0’
($0) Expands to the name of the shell or shell script. This is set
at shell initialization. If Bash is invoked with a file of
- commands (*note Shell Scripts::), '$0' is set to the name of that
- file. If Bash is started with the '-c' option (*note Invoking
- Bash::), then '$0' is set to the first argument after the string to
+ commands (*note Shell Scripts::), ‘$0’ is set to the name of that
+ file. If Bash is started with the ‘-c’ option (*note Invoking
+ Bash::), then ‘$0’ is set to the first argument after the string to
be executed, if one is present. Otherwise, it is set to the
filename used to invoke Bash, as given by argument zero.
====================
Expansion is performed on the command line after it has been split into
-'token's. There are seven kinds of expansion performed:
+‘token’s. Bash performs these expansions:
- * brace expansion
- * tilde expansion
- * parameter and variable expansion
- * command substitution
- * arithmetic expansion
- * word splitting
- * filename expansion
+ • brace expansion
+ • tilde expansion
+ • parameter and variable expansion
+ • command substitution
+ • arithmetic expansion
+ • word splitting
+ • filename expansion
+ • quote removal
* Menu:
The order of expansions is: brace expansion; tilde expansion,
parameter and variable expansion, arithmetic expansion, and command
-substitution (done in a left-to-right fashion); word splitting; and
-filename expansion.
+substitution (done in a left-to-right fashion); word splitting; filename
+expansion; and quote removal.
On systems that can support it, there is an additional expansion
-available: "process substitution". This is performed at the same time
+available: “process substitution”. This is performed at the same time
as tilde, parameter, variable, and arithmetic expansion and command
substitution.
- After these expansions are performed, quote characters present in the
-original word are removed unless they have been quoted themselves
-("quote removal"). *Note Quote Removal:: for more details.
+ “Quote removal” is always performed last. It removes quote
+characters present in the original word, not ones resulting from one of
+the other expansions, unless they have been quoted themselves. *Note
+Quote Removal:: for more details.
Only brace expansion, word splitting, and filename expansion can
increase the number of words of the expansion; other expansions expand a
single word to a single word. The only exceptions to this are the
-expansions of '"$@"' and '$*' (*note Special Parameters::), and
-'"${NAME[@]}"' and '${NAME[*]}' (*note Arrays::).
+expansions of ‘"$@"’ and ‘$*’ (*note Special Parameters::), and
+‘"${NAME[@]}"’ and ‘${NAME[*]}’ (*note Arrays::).
\1f
File: bash.info, Node: Brace Expansion, Next: Tilde Expansion, Up: Shell Expansions
---------------------
Brace expansion is a mechanism by which arbitrary strings may be
-generated. This mechanism is similar to "filename expansion" (*note
+generated. This mechanism is similar to “filename expansion” (*note
Filename Expansion::), but the filenames generated need not exist.
Patterns to be brace expanded take the form of an optional PREAMBLE,
followed by either a series of comma-separated strings or a sequence
bash$ echo a{d,c,b}e
ade ace abe
- A sequence expression takes the form '{X..Y[..INCR]}', where X and Y
+ A sequence expression takes the form ‘{X..Y[..INCR]}’, where X and Y
are either integers or letters, and INCR, an optional increment, is an
integer. When integers are supplied, the expression expands to each
-number between X and Y, inclusive. Supplied integers may be prefixed
-with '0' to force each term to have the same width. When either X or Y
-begins with a zero, the shell attempts to force all generated terms to
-contain the same number of digits, zero-padding where necessary. When
-letters are supplied, the expression expands to each character
-lexicographically between X and Y, inclusive, using the default C
-locale. Note that both X and Y must be of the same type (integer or
-letter). When the increment is supplied, it is used as the difference
-between each term. The default increment is 1 or -1 as appropriate.
+number between X and Y, inclusive. When either X or Y begins with a
+zero, the shell attempts to force all generated terms to contain the
+same number of digits, zero-padding where necessary. When letters are
+supplied, the expression expands to each character lexicographically
+between X and Y, inclusive, using the default C locale. Note that both
+X and Y must be of the same type (integer or letter). When the
+increment is supplied, it is used as the difference between each term.
+The default increment is 1 or -1 as appropriate.
Brace expansion is performed before any other expansions, and any
characters special to other expansions are preserved in the result. It
closing braces, and at least one unquoted comma or a valid sequence
expression. Any incorrectly formed brace expansion is left unchanged.
- A { or ',' may be quoted with a backslash to prevent its being
+ A { or ‘,’ may be quoted with a backslash to prevent its being
considered part of a brace expression. To avoid conflicts with
-parameter expansion, the string '${' is not considered eligible for
-brace expansion, and inhibits brace expansion until the closing '}'.
+parameter expansion, the string ‘${’ is not considered eligible for
+brace expansion, and inhibits brace expansion until the closing ‘}’.
This construct is typically used as shorthand when the common prefix
of the strings to be generated is longer than in the above example:
3.5.2 Tilde Expansion
---------------------
-If a word begins with an unquoted tilde character ('~'), all of the
+If a word begins with an unquoted tilde character (‘~’), all of the
characters up to the first unquoted slash (or all characters, if there
-is no unquoted slash) are considered a "tilde-prefix". If none of the
+is no unquoted slash) are considered a “tilde-prefix”. If none of the
characters in the tilde-prefix are quoted, the characters in the
-tilde-prefix following the tilde are treated as a possible "login name".
+tilde-prefix following the tilde are treated as a possible “login name”.
If this login name is the null string, the tilde is replaced with the
-value of the 'HOME' shell variable. If 'HOME' is unset, the home
+value of the ‘HOME’ shell variable. If ‘HOME’ is unset, the home
directory of the user executing the shell is substituted instead.
Otherwise, the tilde-prefix is replaced with the home directory
associated with the specified login name.
- If the tilde-prefix is '~+', the value of the shell variable 'PWD'
-replaces the tilde-prefix. If the tilde-prefix is '~-', the value of
-the shell variable 'OLDPWD', if it is set, is substituted.
+ If the tilde-prefix is ‘~+’, the value of the shell variable ‘PWD’
+replaces the tilde-prefix. If the tilde-prefix is ‘~-’, the value of
+the shell variable ‘OLDPWD’, if it is set, is substituted.
If the characters following the tilde in the tilde-prefix consist of
-a number N, optionally prefixed by a '+' or a '-', the tilde-prefix is
+a number N, optionally prefixed by a ‘+’ or a ‘-’, the tilde-prefix is
replaced with the corresponding element from the directory stack, as it
-would be displayed by the 'dirs' builtin invoked with the characters
+would be displayed by the ‘dirs’ builtin invoked with the characters
following tilde in the tilde-prefix as an argument (*note The Directory
Stack::). If the tilde-prefix, sans the tilde, consists of a number
-without a leading '+' or '-', '+' is assumed.
+without a leading ‘+’ or ‘-’, ‘+’ is assumed.
If the login name is invalid, or the tilde expansion fails, the word
is left unchanged.
Each variable assignment is checked for unquoted tilde-prefixes
-immediately following a ':' or the first '='. In these cases, tilde
+immediately following a ‘:’ or the first ‘=’. In these cases, tilde
expansion is also performed. Consequently, one may use filenames with
-tildes in assignments to 'PATH', 'MAILPATH', and 'CDPATH', and the shell
+tildes in assignments to ‘PATH’, ‘MAILPATH’, and ‘CDPATH’, and the shell
assigns the expanded value.
The following table shows how Bash treats unquoted tilde-prefixes:
-'~'
- The value of '$HOME'
-'~/foo'
- '$HOME/foo'
+‘~’
+ The value of ‘$HOME’
+‘~/foo’
+ ‘$HOME/foo’
-'~fred/foo'
- The subdirectory 'foo' of the home directory of the user 'fred'
+‘~fred/foo’
+ The subdirectory ‘foo’ of the home directory of the user ‘fred’
-'~+/foo'
- '$PWD/foo'
+‘~+/foo’
+ ‘$PWD/foo’
-'~-/foo'
- '${OLDPWD-'~-'}/foo'
+‘~-/foo’
+ ‘${OLDPWD-'~-'}/foo’
-'~N'
- The string that would be displayed by 'dirs +N'
+‘~N’
+ The string that would be displayed by ‘dirs +N’
-'~+N'
- The string that would be displayed by 'dirs +N'
+‘~+N’
+ The string that would be displayed by ‘dirs +N’
-'~-N'
- The string that would be displayed by 'dirs -N'
+‘~-N’
+ The string that would be displayed by ‘dirs -N’
Bash also performs tilde expansion on words satisfying the conditions
of variable assignments (*note Shell Parameters::) when they appear as
3.5.3 Shell Parameter Expansion
-------------------------------
-The '$' character introduces parameter expansion, command substitution,
+The ‘$’ character introduces parameter expansion, command substitution,
or arithmetic expansion. The parameter name or symbol to be expanded
may be enclosed in braces, which are optional but serve to protect the
variable to be expanded from characters immediately following it which
could be interpreted as part of the name.
- When braces are used, the matching ending brace is the first '}' not
+ When braces are used, the matching ending brace is the first ‘}’ not
escaped by a backslash or within a quoted string, and not within an
embedded arithmetic expansion, command substitution, or parameter
expansion.
uses the value formed by expanding the rest of PARAMETER as the new
PARAMETER; this is then expanded and that value is used in the rest of
the expansion, rather than the expansion of the original PARAMETER.
-This is known as 'indirect expansion'. The value is subject to tilde
+This is known as ‘indirect expansion’. The value is subject to tilde
expansion, parameter expansion, command substitution, and arithmetic
expansion. If PARAMETER is a nameref, this expands to the name of the
variable referenced by PARAMETER instead of performing the complete
parameter expansion, command substitution, and arithmetic expansion.
When not performing substring expansion, using the forms described
-below (e.g., ':-'), Bash tests for a parameter that is unset or null.
+below (e.g., ‘:-’), Bash tests for a parameter that is unset or null.
Omitting the colon results in a test only for a parameter that is unset.
Put another way, if the colon is included, the operator tests for both
PARAMETER's existence and that its value is not null; if the colon is
omitted, the operator tests only for existence.
-'${PARAMETER:-WORD}'
+‘${PARAMETER:−WORD}’
If PARAMETER is unset or null, the expansion of WORD is
substituted. Otherwise, the value of PARAMETER is substituted.
$ echo ${v:-unset-or-null}
unset-or-null
-'${PARAMETER:=WORD}'
+‘${PARAMETER:=WORD}’
If PARAMETER is unset or null, the expansion of WORD is assigned to
PARAMETER. The value of PARAMETER is then substituted. Positional
parameters and special parameters may not be assigned to in this
$ echo $var
DEFAULT
-'${PARAMETER:?WORD}'
+‘${PARAMETER:?WORD}’
If PARAMETER is null or unset, the expansion of WORD (or a message
to that effect if WORD is not present) is written to the standard
error and the shell, if it is not interactive, exits. Otherwise,
$ : ${var:?var is unset or null}
bash: var: var is unset or null
-'${PARAMETER:+WORD}'
+‘${PARAMETER:+WORD}’
If PARAMETER is null or unset, nothing is substituted, otherwise
the expansion of WORD is substituted.
$ echo ${var:+var is set and not null}
var is set and not null
-'${PARAMETER:OFFSET}'
-'${PARAMETER:OFFSET:LENGTH}'
+‘${PARAMETER:OFFSET}’
+‘${PARAMETER:OFFSET:LENGTH}’
This is referred to as Substring Expansion. It expands to up to
LENGTH characters of the value of PARAMETER starting at the
- character specified by OFFSET. If PARAMETER is '@' or '*', an
- indexed array subscripted by '@' or '*', or an associative array
+ character specified by OFFSET. If PARAMETER is ‘@’ or ‘*’, an
+ indexed array subscripted by ‘@’ or ‘*’, or an associative array
name, the results differ as described below. If LENGTH is omitted,
it expands to the substring of the value of PARAMETER starting at
the character specified by OFFSET and extending to the end of the
rather than a number of characters, and the expansion is the
characters between OFFSET and that result. Note that a negative
offset must be separated from the colon by at least one space to
- avoid being confused with the ':-' expansion.
+ avoid being confused with the ‘:-’ expansion.
Here are some examples illustrating substring expansion on
parameters and subscripted arrays:
$ echo ${array[0]: -7:-2}
bcdef
- If PARAMETER is '@' or '*', the result is LENGTH positional
+ If PARAMETER is ‘@’ or ‘*’, the result is LENGTH positional
parameters beginning at OFFSET. A negative OFFSET is taken
relative to one greater than the greatest positional parameter, so
an offset of -1 evaluates to the last positional parameter (or 0 if
$ echo ${@: -7:0}
- If PARAMETER is an indexed array name subscripted by '@' or '*',
+ If PARAMETER is an indexed array name subscripted by ‘@’ or ‘*’,
the result is the LENGTH members of the array beginning with
- '${PARAMETER[OFFSET]}'. A negative OFFSET is taken relative to one
+ ‘${PARAMETER[OFFSET]}’. A negative OFFSET is taken relative to one
greater than the maximum index of the specified array. It is an
expansion error if LENGTH evaluates to a number less than zero.
Substring indexing is zero-based unless the positional parameters
are used, in which case the indexing starts at 1 by default. If
- OFFSET is 0, and the positional parameters are used, '$0' is
+ OFFSET is 0, and the positional parameters are used, ‘$0’ is
prefixed to the list.
-'${!PREFIX*}'
-'${!PREFIX@}'
+‘${!PREFIX*}’
+‘${!PREFIX@}’
Expands to the names of variables whose names begin with PREFIX,
- separated by the first character of the 'IFS' special variable.
- When '@' is used and the expansion appears within double quotes,
+ separated by the first character of the ‘IFS’ special variable.
+ When ‘@’ is used and the expansion appears within double quotes,
each variable name expands to a separate word.
-'${!NAME[@]}'
-'${!NAME[*]}'
+‘${!NAME[@]}’
+‘${!NAME[*]}’
If NAME is an array variable, expands to the list of array indices
(keys) assigned in NAME. If NAME is not an array, expands to 0 if
- NAME is set and null otherwise. When '@' is used and the expansion
+ NAME is set and null otherwise. When ‘@’ is used and the expansion
appears within double quotes, each key expands to a separate word.
-'${#PARAMETER}'
+‘${#PARAMETER}’
The length in characters of the expanded value of PARAMETER is
- substituted. If PARAMETER is '*' or '@', the value substituted is
+ substituted. If PARAMETER is ‘*’ or ‘@’, the value substituted is
the number of positional parameters. If PARAMETER is an array name
- subscripted by '*' or '@', the value substituted is the number of
+ subscripted by ‘*’ or ‘@’, the value substituted is the number of
elements in the array. If PARAMETER is an indexed array name
subscripted by a negative number, that number is interpreted as
relative to one greater than the maximum index of PARAMETER, so
negative indices count back from the end of the array, and an index
of -1 references the last element.
-'${PARAMETER#WORD}'
-'${PARAMETER##WORD}'
+‘${PARAMETER#WORD}’
+‘${PARAMETER##WORD}’
The WORD is expanded to produce a pattern and matched according to
the rules described below (*note Pattern Matching::). If the
pattern matches the beginning of the expanded value of PARAMETER,
then the result of the expansion is the expanded value of PARAMETER
- with the shortest matching pattern (the '#' case) or the longest
- matching pattern (the '##' case) deleted. If PARAMETER is '@' or
- '*', the pattern removal operation is applied to each positional
+ with the shortest matching pattern (the ‘#’ case) or the longest
+ matching pattern (the ‘##’ case) deleted. If PARAMETER is ‘@’ or
+ ‘*’, the pattern removal operation is applied to each positional
parameter in turn, and the expansion is the resultant list. If
- PARAMETER is an array variable subscripted with '@' or '*', the
+ PARAMETER is an array variable subscripted with ‘@’ or ‘*’, the
pattern removal operation is applied to each member of the array in
turn, and the expansion is the resultant list.
-'${PARAMETER%WORD}'
-'${PARAMETER%%WORD}'
+‘${PARAMETER%WORD}’
+‘${PARAMETER%%WORD}’
The WORD is expanded to produce a pattern and matched according to
the rules described below (*note Pattern Matching::). If the
pattern matches a trailing portion of the expanded value of
PARAMETER, then the result of the expansion is the value of
- PARAMETER with the shortest matching pattern (the '%' case) or the
- longest matching pattern (the '%%' case) deleted. If PARAMETER is
- '@' or '*', the pattern removal operation is applied to each
+ PARAMETER with the shortest matching pattern (the ‘%’ case) or the
+ longest matching pattern (the ‘%%’ case) deleted. If PARAMETER is
+ ‘@’ or ‘*’, the pattern removal operation is applied to each
positional parameter in turn, and the expansion is the resultant
- list. If PARAMETER is an array variable subscripted with '@' or
- '*', the pattern removal operation is applied to each member of the
+ list. If PARAMETER is an array variable subscripted with ‘@’ or
+ ‘*’, the pattern removal operation is applied to each member of the
array in turn, and the expansion is the resultant list.
-'${PARAMETER/PATTERN/STRING}'
-'${PARAMETER//PATTERN/STRING}'
-'${PARAMETER/#PATTERN/STRING}'
-'${PARAMETER/%PATTERN/STRING}'
+‘${PARAMETER/PATTERN/STRING}’
+‘${PARAMETER//PATTERN/STRING}’
+‘${PARAMETER/#PATTERN/STRING}’
+‘${PARAMETER/%PATTERN/STRING}’
The PATTERN is expanded to produce a pattern just as in filename
expansion. PARAMETER is expanded and the longest match of PATTERN
against its value is replaced with STRING. STRING undergoes tilde
In the first form above, only the first match is replaced. If
there are two slashes separating PARAMETER and PATTERN (the second
form above), all matches of PATTERN are replaced with STRING. If
- PATTERN is preceded by '#' (the third form above), it must match at
+ PATTERN is preceded by ‘#’ (the third form above), it must match at
the beginning of the expanded value of PARAMETER. If PATTERN is
- preceded by '%' (the fourth form above), it must match at the end
+ preceded by ‘%’ (the fourth form above), it must match at the end
of the expanded value of PARAMETER. If the expansion of STRING is
null, matches of PATTERN are deleted. If STRING is null, matches
- of PATTERN are deleted and the '/' following PATTERN may be
+ of PATTERN are deleted and the ‘/’ following PATTERN may be
omitted.
- If the 'patsub_replacement' shell option is enabled using 'shopt',
- any unquoted instances of '&' in STRING are replaced with the
+ If the ‘patsub_replacement’ shell option is enabled using ‘shopt’,
+ any unquoted instances of ‘&’ in STRING are replaced with the
matching portion of PATTERN. This is intended to duplicate a
- common 'sed' idiom.
+ common ‘sed’ idiom.
Quoting any part of STRING inhibits replacement in the expansion of
the quoted portion, including replacement strings stored in shell
- variables. Backslash will escape '&' in STRING; the backslash is
- removed in order to permit a literal '&' in the replacement string.
+ variables. Backslash will escape ‘&’ in STRING; the backslash is
+ removed in order to permit a literal ‘&’ in the replacement string.
Users should take care if STRING is double-quoted to avoid unwanted
interactions between the backslash and double-quoting, since
backslash has special meaning within double quotes. Pattern
- substitution performs the check for unquoted '&' after expanding
+ substitution performs the check for unquoted ‘&’ after expanding
STRING, so users should ensure to properly quote any occurrences of
- '&' they want to be taken literally in the replacement and ensure
- any instances of '&' they want to be replaced are unquoted.
+ ‘&’ they want to be taken literally in the replacement and ensure
+ any instances of ‘&’ they want to be replaced are unquoted.
For instance,
a context that doesn't take any enclosing double quotes into
account.
- Since backslash can escape '&', it can also escape a backslash in
- the replacement string. This means that '\\' will insert a literal
- backslash into the replacement, so these two 'echo' commands
+ Since backslash can escape ‘&’, it can also escape a backslash in
+ the replacement string. This means that ‘\\’ will insert a literal
+ backslash into the replacement, so these two ‘echo’ commands
var=abcdef
rep='\\&xyz'
echo ${var/abc/\\&xyz}
echo ${var/abc/$rep}
- will both output '\abcxyzdef'.
+ will both output ‘\abcxyzdef’.
It should rarely be necessary to enclose only STRING in double
quotes.
- If the 'nocasematch' shell option (see the description of 'shopt'
+ If the ‘nocasematch’ shell option (see the description of ‘shopt’
in *note The Shopt Builtin::) is enabled, the match is performed
without regard to the case of alphabetic characters. If PARAMETER
- is '@' or '*', the substitution operation is applied to each
+ is ‘@’ or ‘*’, the substitution operation is applied to each
positional parameter in turn, and the expansion is the resultant
- list. If PARAMETER is an array variable subscripted with '@' or
- '*', the substitution operation is applied to each member of the
+ list. If PARAMETER is an array variable subscripted with ‘@’ or
+ ‘*’, the substitution operation is applied to each member of the
array in turn, and the expansion is the resultant list.
-'${PARAMETER^PATTERN}'
-'${PARAMETER^^PATTERN}'
-'${PARAMETER,PATTERN}'
-'${PARAMETER,,PATTERN}'
+‘${PARAMETER^PATTERN}’
+‘${PARAMETER^^PATTERN}’
+‘${PARAMETER,PATTERN}’
+‘${PARAMETER,,PATTERN}’
This expansion modifies the case of alphabetic characters in
PARAMETER. The PATTERN is expanded to produce a pattern just as in
filename expansion. Each character in the expanded value of
pattern, its case is converted. The pattern should not attempt to
match more than one character.
- The '^' operator converts lowercase letters matching PATTERN to
- uppercase; the ',' operator converts matching uppercase letters to
- lowercase. The '^^' and ',,' expansions convert each matched
- character in the expanded value; the '^' and ',' expansions match
+ The ‘^’ operator converts lowercase letters matching PATTERN to
+ uppercase; the ‘,’ operator converts matching uppercase letters to
+ lowercase. The ‘^^’ and ‘,,’ expansions convert each matched
+ character in the expanded value; the ‘^’ and ‘,’ expansions match
and convert only the first character in the expanded value. If
- PATTERN is omitted, it is treated like a '?', which matches every
+ PATTERN is omitted, it is treated like a ‘?’, which matches every
character.
- If PARAMETER is '@' or '*', the case modification operation is
+ If PARAMETER is ‘@’ or ‘*’, the case modification operation is
applied to each positional parameter in turn, and the expansion is
the resultant list. If PARAMETER is an array variable subscripted
- with '@' or '*', the case modification operation is applied to each
+ with ‘@’ or ‘*’, the case modification operation is applied to each
member of the array in turn, and the expansion is the resultant
list.
-'${PARAMETER@OPERATOR}'
+‘${PARAMETER@OPERATOR}’
The expansion is either a transformation of the value of PARAMETER
or information about PARAMETER itself, depending on the value of
OPERATOR. Each OPERATOR is a single letter:
- 'U'
+ ‘U’
The expansion is a string that is the value of PARAMETER with
lowercase alphabetic characters converted to uppercase.
- 'u'
+ ‘u’
The expansion is a string that is the value of PARAMETER with
the first character converted to uppercase, if it is
alphabetic.
- 'L'
+ ‘L’
The expansion is a string that is the value of PARAMETER with
uppercase alphabetic characters converted to lowercase.
- 'Q'
+ ‘Q’
The expansion is a string that is the value of PARAMETER
quoted in a format that can be reused as input.
- 'E'
+ ‘E’
The expansion is a string that is the value of PARAMETER with
- backslash escape sequences expanded as with the '$'...''
+ backslash escape sequences expanded as with the ‘$'...'’
quoting mechanism.
- 'P'
+ ‘P’
The expansion is a string that is the result of expanding the
value of PARAMETER as if it were a prompt string (*note
Controlling the Prompt::).
- 'A'
+ ‘A’
The expansion is a string in the form of an assignment
- statement or 'declare' command that, if evaluated, will
+ statement or ‘declare’ command that, if evaluated, will
recreate PARAMETER with its attributes and value.
- 'K'
+ ‘K’
Produces a possibly-quoted version of the value of PARAMETER,
except that it prints the values of indexed and associative
arrays as a sequence of quoted key-value pairs (*note
Arrays::).
- 'a'
+ ‘a’
The expansion is a string consisting of flag values
representing PARAMETER's attributes.
- 'k'
- Like the 'K' transformation, but expands the keys and values
+ ‘k’
+ Like the ‘K’ transformation, but expands the keys and values
of indexed and associative arrays to separate words after word
splitting.
- If PARAMETER is '@' or '*', the operation is applied to each
+ If PARAMETER is ‘@’ or ‘*’, the operation is applied to each
positional parameter in turn, and the expansion is the resultant
- list. If PARAMETER is an array variable subscripted with '@' or
- '*', the operation is applied to each member of the array in turn,
+ list. If PARAMETER is an array variable subscripted with ‘@’ or
+ ‘*’, the operation is applied to each member of the array in turn,
and the expansion is the resultant list.
The result of the expansion is subject to word splitting and
environment and replacing the command substitution with the standard
output of the command, with any trailing newlines deleted. Embedded
newlines are not deleted, but they may be removed during word splitting.
-The command substitution '$(cat FILE)' can be replaced by the equivalent
-but faster '$(< FILE)'.
+The command substitution ‘$(cat FILE)’ can be replaced by the equivalent
+but faster ‘$(< FILE)’.
With the old-style backquote form of substitution, backslash retains
-its literal meaning except when followed by '$', '`', or '\'. The first
+its literal meaning except when followed by ‘$’, ‘`’, or ‘\’. The first
backquote not preceded by a backslash terminates the command
-substitution. When using the '$(COMMAND)' form, all characters between
+substitution. When using the ‘$(COMMAND)’ form, all characters between
the parentheses make up the command; none are treated specially.
There is an alternate form of command substitution:
its output, again with trailing newlines removed.
The character C following the open brace must be a space, tab,
-newline, or '|', and the close brace must be in a position where a
+newline, or ‘|’, and the close brace must be in a position where a
reserved word may appear (i.e., preceded by a command terminator such as
semicolon). Bash allows the close brace to be joined to the remaining
characters in the word without being followed by a shell metacharacter
Any side effects of COMMAND take effect immediately in the current
execution environment and persist in the current environment after the
-command completes (e.g., the 'exit' builtin will exit the shell).
+command completes (e.g., the ‘exit’ builtin will exit the shell).
This type of command substitution superficially resembles executing
an unnamed shell function: local variables are created as when a shell
-function is executing, and the 'return' builtin forces COMMAND to
+function is executing, and the ‘return’ builtin forces COMMAND to
complete; however, the rest of the execution environment, including the
positional parameters, is shared with the caller.
- If the first character following the open brace is a '|', the
-construct expands to the value of the 'REPLY' shell variable after
+ If the first character following the open brace is a ‘|’, the
+construct expands to the value of the ‘REPLY’ shell variable after
COMMAND executes, without removing any trailing newlines, and the
standard output of COMMAND remains the same as in the calling shell.
-Bash creates 'REPLY' as an initially-unset local variable when COMMAND
-executes, and restores 'REPLY' to the value it had before the command
+Bash creates ‘REPLY’ as an initially-unset local variable when COMMAND
+executes, and restores ‘REPLY’ to the value it had before the command
substitution after COMMAND completes, as with any local variable.
- For example, this construct expands to '12345', and leaves the shell
-variable 'X' unchanged in the current execution environment:
+ For example, this construct expands to ‘12345’, and leaves the shell
+variable ‘X’ unchanged in the current execution environment:
${ local X=12345 ; echo $X; }
-(not declaring 'X' as local would modify its value in the current
+(not declaring ‘X’ as local would modify its value in the current
environment, as with normal shell function execution), while this
-construct does not require any output to expand to '12345':
+construct does not require any output to expand to ‘12345’:
${| REPLY=12345; }
-and restores 'REPLY' to the value it had before the command
+and restores ‘REPLY’ to the value it had before the command
substitution.
Command substitutions may be nested. To nest when using the
>(LIST)
The process LIST is run asynchronously, and its input or output appears
as a filename. This filename is passed as an argument to the current
-command as the result of the expansion. If the '>(LIST)' form is used,
-writing to the file will provide input for LIST. If the '<(LIST)' form
+command as the result of the expansion. If the ‘>(LIST)’ form is used,
+writing to the file will provide input for LIST. If the ‘<(LIST)’ form
is used, the file passed as an argument should be read to obtain the
-output of LIST. Note that no space may appear between the '<' or '>'
+output of LIST. Note that no space may appear between the ‘<’ or ‘>’
and the left parenthesis, otherwise the construct would be interpreted
as a redirection. Process substitution is supported on systems that
-support named pipes (FIFOs) or the '/dev/fd' method of naming open
+support named pipes (FIFOs) or the ‘/dev/fd’ method of naming open
files.
When available, process substitution is performed simultaneously with
substitution, and arithmetic expansion that did not occur within double
quotes for word splitting.
- The shell treats each character of '$IFS' as a delimiter, and splits
+ The shell treats each character of ‘$IFS’ as a delimiter, and splits
the results of the other expansions into words using these characters as
field terminators.
- If 'IFS' is unset, or its value is exactly '<space><tab><newline>',
-the default, then sequences of 'space', 'tab', and 'newline' at the
+ If ‘IFS’ is unset, or its value is exactly ‘<space><tab><newline>’,
+the default, then sequences of ‘space’, ‘tab’, and ‘newline’ at the
beginning and end of the results of the previous expansions are ignored,
-and any sequence of 'IFS' characters not at the beginning or end serves
-to delimit words. If 'IFS' has a value other than the default, then
-sequences of the whitespace characters 'space', 'tab', and 'newline' are
+and any sequence of ‘IFS’ characters not at the beginning or end serves
+to delimit words. If ‘IFS’ has a value other than the default, then
+sequences of the whitespace characters ‘space’, ‘tab’, and ‘newline’ are
ignored at the beginning and end of the word, as long as the whitespace
-character is in the value of 'IFS' (an 'IFS' whitespace character). Any
-character in 'IFS' that is not 'IFS' whitespace, along with any adjacent
-'IFS' whitespace characters, delimits a field. A sequence of 'IFS'
+character is in the value of ‘IFS’ (an ‘IFS’ whitespace character). Any
+character in ‘IFS’ that is not ‘IFS’ whitespace, along with any adjacent
+‘IFS’ whitespace characters, delimits a field. A sequence of ‘IFS’
whitespace characters is also treated as a delimiter.
- If the value of 'IFS' is null, no word splitting occurs. If 'IFS' is
+ If the value of ‘IFS’ is null, no word splitting occurs. If ‘IFS’ is
unset, word splitting behaves as if it contained the default value
-'<space><tab><newline>'.
+‘<space><tab><newline>’.
- Explicit null arguments ('""' or '''') are retained and passed to
+ Explicit null arguments (‘""’ or ‘''’) are retained and passed to
commands as empty strings. Unquoted implicit null arguments, resulting
from the expansion of parameters that have no values, are removed. If a
parameter with no value is expanded within double quotes, a null
argument results and is retained and passed to a command as an empty
string. When a quoted null argument appears as part of a word whose
expansion is non-null, the null argument is removed. That is, the word
-'-d''' becomes '-d' after word splitting and null argument removal.
+‘-d''’ becomes ‘-d’ after word splitting and null argument removal.
Note that if no expansion occurs, no splitting is performed.
* Pattern Matching:: How the shell matches patterns.
-After word splitting, unless the '-f' option has been set (*note The Set
-Builtin::), Bash scans each word for the characters '*', '?', and '['.
+After word splitting, unless the ‘-f’ option has been set (*note The Set
+Builtin::), Bash scans each word for the characters ‘*’, ‘?’, and ‘[’.
If one of these characters appears, and is not quoted, then the word is
regarded as a PATTERN, and replaced with an alphabetically sorted list
of filenames matching the pattern (*note Pattern Matching::). If no
-matching filenames are found, and the shell option 'nullglob' is
-disabled, the word is left unchanged. If the 'nullglob' option is set,
-and no matches are found, the word is removed. If the 'failglob' shell
+matching filenames are found, and the shell option ‘nullglob’ is
+disabled, the word is left unchanged. If the ‘nullglob’ option is set,
+and no matches are found, the word is removed. If the ‘failglob’ shell
option is set, and no matches are found, an error message is printed and
-the command is not executed. If the shell option 'nocaseglob' is
+the command is not executed. If the shell option ‘nocaseglob’ is
enabled, the match is performed without regard to the case of alphabetic
characters.
- When a pattern is used for filename expansion, the character '.' at
+ When a pattern is used for filename expansion, the character ‘.’ at
the start of a filename or immediately following a slash must be matched
-explicitly, unless the shell option 'dotglob' is set. In order to match
-the filenames '.' and '..', the pattern must begin with '.' (for
-example, '.?'), even if 'dotglob' is set. If the 'globskipdots' shell
-option is enabled, the filenames '.' and '..' are never matched, even if
-the pattern begins with a '.'. When not matching filenames, the '.'
+explicitly, unless the shell option ‘dotglob’ is set. In order to match
+the filenames ‘.’ and ‘..’, the pattern must begin with ‘.’ (for
+example, ‘.?’), even if ‘dotglob’ is set. If the ‘globskipdots’ shell
+option is enabled, the filenames ‘.’ and ‘..’ never match, even if the
+pattern begins with a ‘.’. When not matching filenames, the ‘.’
character is not treated specially.
When matching a filename, the slash character must always be matched
can be matched by a special pattern character as described below (*note
Pattern Matching::).
- See the description of 'shopt' in *note The Shopt Builtin::, for a
-description of the 'nocaseglob', 'nullglob', 'globskipdots', 'failglob',
-and 'dotglob' options.
-
- The 'GLOBIGNORE' shell variable may be used to restrict the set of
-file names matching a pattern. If 'GLOBIGNORE' is set, each matching
-file name that also matches one of the patterns in 'GLOBIGNORE' is
-removed from the list of matches. If the 'nocaseglob' option is set,
-the matching against the patterns in 'GLOBIGNORE' is performed without
-regard to case. The filenames '.' and '..' are always ignored when
-'GLOBIGNORE' is set and not null. However, setting 'GLOBIGNORE' to a
-non-null value has the effect of enabling the 'dotglob' shell option, so
-all other filenames beginning with a '.' will match. To get the old
-behavior of ignoring filenames beginning with a '.', make '.*' one of
-the patterns in 'GLOBIGNORE'. The 'dotglob' option is disabled when
-'GLOBIGNORE' is unset.
+ See the description of ‘shopt’ in *note The Shopt Builtin::, for a
+description of the ‘nocaseglob’, ‘nullglob’, ‘globskipdots’, ‘failglob’,
+and ‘dotglob’ options.
+
+ The ‘GLOBIGNORE’ shell variable may be used to restrict the set of
+file names matching a pattern. If ‘GLOBIGNORE’ is set, each matching
+file name that also matches one of the patterns in ‘GLOBIGNORE’ is
+removed from the list of matches. If the ‘nocaseglob’ option is set,
+the matching against the patterns in ‘GLOBIGNORE’ is performed without
+regard to case. The filenames ‘.’ and ‘..’ are always ignored when
+‘GLOBIGNORE’ is set and not null. However, setting ‘GLOBIGNORE’ to a
+non-null value has the effect of enabling the ‘dotglob’ shell option, so
+all other filenames beginning with a ‘.’ will match. To get the old
+behavior of ignoring filenames beginning with a ‘.’, make ‘.*’ one of
+the patterns in ‘GLOBIGNORE’. The ‘dotglob’ option is disabled when
+‘GLOBIGNORE’ is unset.
After the pattern is expanded and matched against filenames, the
-value of the 'GLOBSORT' variable controls how the results are sorted, as
+value of the ‘GLOBSORT’ variable controls how the results are sorted, as
described below (*note Bash Variables::).
\1f
characters must be quoted if they are to be matched literally.
The special pattern characters have the following meanings:
-'*'
- Matches any string, including the null string. When the 'globstar'
- shell option is enabled, and '*' is used in a filename expansion
- context, two adjacent '*'s used as a single pattern will match all
+‘*’
+ Matches any string, including the null string. When the ‘globstar’
+ shell option is enabled, and ‘*’ is used in a filename expansion
+ context, two adjacent ‘*’s used as a single pattern will match all
files and zero or more directories and subdirectories. If followed
- by a '/', two adjacent '*'s will match only directories and
+ by a ‘/’, two adjacent ‘*’s will match only directories and
subdirectories.
-'?'
+‘?’
Matches any single character.
-'[...]'
+‘[...]’
Matches any one of the enclosed characters. A pair of characters
separated by a hyphen denotes a RANGE EXPRESSION; any character
that falls between those two characters, inclusive, using the
current locale's collating sequence and character set, is matched.
- If the first character following the '[' is a '!' or a '^' then any
- character not enclosed is matched. A '-' may be matched by
- including it as the first or last character in the set. A ']' may
+ If the first character following the ‘[’ is a ‘!’ or a ‘^’ then any
+ character not enclosed is matched. A ‘−’ may be matched by
+ including it as the first or last character in the set. A ‘]’ may
be matched by including it as the first character in the set. The
sorting order of characters in range expressions, and the
characters included in the range, are determined by the current
- locale and the values of the 'LC_COLLATE' and 'LC_ALL' shell
+ locale and the values of the ‘LC_COLLATE’ and ‘LC_ALL’ shell
variables, if set.
- For example, in the default C locale, '[a-dx-z]' is equivalent to
- '[abcdxyz]'. Many locales sort characters in dictionary order, and
- in these locales '[a-dx-z]' is typically not equivalent to
- '[abcdxyz]'; it might be equivalent to '[aBbCcDdxYyZz]', for
+ For example, in the default C locale, ‘[a-dx-z]’ is equivalent to
+ ‘[abcdxyz]’. Many locales sort characters in dictionary order, and
+ in these locales ‘[a-dx-z]’ is typically not equivalent to
+ ‘[abcdxyz]’; it might be equivalent to ‘[aBbCcDdxYyZz]’, for
example. To obtain the traditional interpretation of ranges in
bracket expressions, you can force the use of the C locale by
- setting the 'LC_COLLATE' or 'LC_ALL' environment variable to the
- value 'C', or enable the 'globasciiranges' shell option.
+ setting the ‘LC_COLLATE’ or ‘LC_ALL’ environment variable to the
+ value ‘C’, or enable the ‘globasciiranges’ shell option.
- Within '[' and ']', "character classes" can be specified using the
- syntax '[:'CLASS':]', where CLASS is one of the following classes
+ Within ‘[’ and ‘]’, “character classes” can be specified using the
+ syntax ‘[:’CLASS‘:]’, where CLASS is one of the following classes
defined in the POSIX standard:
alnum alpha ascii blank cntrl digit graph lower
print punct space upper word xdigit
A character class matches any character belonging to that class.
- The 'word' character class matches letters, digits, and the
- character '_'.
+ The ‘word’ character class matches letters, digits, and the
+ character ‘_’.
- Within '[' and ']', an "equivalence class" can be specified using
- the syntax '[='C'=]', which matches all characters with the same
+ Within ‘[’ and ‘]’, an “equivalence class” can be specified using
+ the syntax ‘[=’C‘=]’, which matches all characters with the same
collation weight (as defined by the current locale) as the
character C.
- Within '[' and ']', the syntax '[.'SYMBOL'.]' matches the collating
+ Within ‘[’ and ‘]’, the syntax ‘[.’SYMBOL‘.]’ matches the collating
symbol SYMBOL.
- If the 'extglob' shell option is enabled using the 'shopt' builtin,
+ If the ‘extglob’ shell option is enabled using the ‘shopt’ builtin,
the shell recognizes several extended pattern matching operators. In
the following description, a PATTERN-LIST is a list of one or more
-patterns separated by a '|'. When matching filenames, the 'dotglob'
+patterns separated by a ‘|’. When matching filenames, the ‘dotglob’
shell option determines the set of filenames that are tested, as
described above. Composite patterns may be formed using one or more of
the following sub-patterns:
-'?(PATTERN-LIST)'
+‘?(PATTERN-LIST)’
Matches zero or one occurrence of the given patterns.
-'*(PATTERN-LIST)'
+‘*(PATTERN-LIST)’
Matches zero or more occurrences of the given patterns.
-'+(PATTERN-LIST)'
+‘+(PATTERN-LIST)’
Matches one or more occurrences of the given patterns.
-'@(PATTERN-LIST)'
+‘@(PATTERN-LIST)’
Matches one of the given patterns.
-'!(PATTERN-LIST)'
+‘!(PATTERN-LIST)’
Matches anything except one of the given patterns.
- The 'extglob' option changes the behavior of the parser, since the
+ The ‘extglob’ option changes the behavior of the parser, since the
parentheses are normally treated as operators with syntactic meaning.
To ensure that extended matching patterns are parsed correctly, make
-sure that 'extglob' is enabled before parsing constructs containing the
+sure that ‘extglob’ is enabled before parsing constructs containing the
patterns, including shell functions and command substitutions.
- When matching filenames, the 'dotglob' shell option determines the
-set of filenames that are tested: when 'dotglob' is enabled, the set of
-filenames includes all files beginning with '.', but the filenames '.'
-and '..' must be matched by a pattern or sub-pattern that begins with a
+ When matching filenames, the ‘dotglob’ shell option determines the
+set of filenames that are tested: when ‘dotglob’ is enabled, the set of
+filenames includes all files beginning with ‘.’, but the filenames ‘.’
+and ‘..’ must be matched by a pattern or sub-pattern that begins with a
dot; when it is disabled, the set does not include any filenames
-beginning with "." unless the pattern or sub-pattern begins with a '.'.
-As above, '.' only has a special meaning when matching filenames.
+beginning with "." unless the pattern or sub-pattern begins with a ‘.’.
+As above, ‘.’ only has a special meaning when matching filenames.
Complicated extended pattern matching against long strings is slow,
especially when the patterns contain alternations and the strings
-------------------
After the preceding expansions, all unquoted occurrences of the
-characters '\', ''', and '"' that did not result from one of the above
+characters ‘\’, ‘'’, and ‘"’ that did not result from one of the above
expansions are removed.
\1f
3.6 Redirections
================
-Before a command is executed, its input and output may be "redirected"
-using a special notation interpreted by the shell. "Redirection" allows
+Before a command is executed, its input and output may be “redirected”
+using a special notation interpreted by the shell. “Redirection” allows
commands' file handles to be duplicated, opened, closed, made to refer
to different files, and can change the files the command reads from and
writes to. Redirection may also be used to modify file handles in the
<&- is preceded by {VARNAME}, the value of VARNAME defines the file
descriptor to close. If {VARNAME} is supplied, the redirection persists
beyond the scope of the command, allowing the shell programmer to manage
-the file descriptor's lifetime manually. The 'varredir_close' shell
+the file descriptor's lifetime manually. The ‘varredir_close’ shell
option manages this behavior (*note The Shopt Builtin::).
In the following descriptions, if the file descriptor number is
-omitted, and the first character of the redirection operator is '<', the
+omitted, and the first character of the redirection operator is ‘<’, the
redirection refers to the standard input (file descriptor 0). If the
-first character of the redirection operator is '>', the redirection
+first character of the redirection operator is ‘>’, the redirection
refers to the standard output (file descriptor 1).
The word following the redirection operator in the following
use them; otherwise it will emulate them internally with the behavior
described below.
-'/dev/fd/FD'
+‘/dev/fd/FD’
If FD is a valid integer, file descriptor FD is duplicated.
-'/dev/stdin'
+‘/dev/stdin’
File descriptor 0 is duplicated.
-'/dev/stdout'
+‘/dev/stdout’
File descriptor 1 is duplicated.
-'/dev/stderr'
+‘/dev/stderr’
File descriptor 2 is duplicated.
-'/dev/tcp/HOST/PORT'
+‘/dev/tcp/HOST/PORT’
If HOST is a valid hostname or Internet address, and PORT is an
integer port number or service name, Bash attempts to open the
corresponding TCP socket.
-'/dev/udp/HOST/PORT'
+‘/dev/udp/HOST/PORT’
If HOST is a valid hostname or Internet address, and PORT is an
integer port number or service name, Bash attempts to open the
corresponding UDP socket.
-----------------------
Redirection of input causes the file whose name results from the
-expansion of WORD to be opened for reading on file descriptor 'n', or
-the standard input (file descriptor 0) if 'n' is not specified.
+expansion of WORD to be opened for reading on file descriptor ‘n’, or
+the standard input (file descriptor 0) if ‘n’ is not specified.
The general format for redirecting input is:
[N]<WORD
The general format for redirecting output is:
[N]>[|]WORD
- If the redirection operator is '>', and the 'noclobber' option to the
-'set' builtin has been enabled, the redirection will fail if the file
+ If the redirection operator is ‘>’, and the ‘noclobber’ option to the
+‘set’ builtin has been enabled, the redirection will fail if the file
whose name results from the expansion of WORD exists and is a regular
-file. If the redirection operator is '>|', or the redirection operator
-is '>' and the 'noclobber' option is not enabled, the redirection is
+file. If the redirection operator is ‘>|’, or the redirection operator
+is ‘>’ and the ‘noclobber’ option is not enabled, the redirection is
attempted even if the file named by WORD exists.
3.6.3 Appending Redirected Output
Of the two forms, the first is preferred. This is semantically
equivalent to
>WORD 2>&1
- When using the second form, WORD may not expand to a number or '-'.
+ When using the second form, WORD may not expand to a number or ‘-’.
If it does, other redirection operators apply (see Duplicating File
Descriptors below) for compatibility reasons.
command.
The format of here-documents is:
- [N]<<[-]WORD
+ [N]<<[−]WORD
HERE-DOCUMENT
DELIMITER
If WORD is unquoted, DELIMITER is WORD itself, all lines of the
here-document are subjected to parameter expansion, command
substitution, and arithmetic expansion, the character sequence
-'\newline' is ignored, and '\' must be used to quote the characters '\',
-'$', and '`'.
+‘\newline’ is ignored, and ‘\’ must be used to quote the characters ‘\’,
+‘$’, and ‘`’.
- If the redirection operator is '<<-', then all leading tab characters
+ If the redirection operator is ‘<<-’, then all leading tab characters
are stripped from input lines and the line containing DELIMITER. This
allows here-documents within shell scripts to be indented in a natural
fashion.
more digits, the file descriptor denoted by N is made to be a copy of
that file descriptor. If the digits in WORD do not specify a file
descriptor open for input, a redirection error occurs. If WORD
-evaluates to '-', file descriptor N is closed. If N is not specified,
+evaluates to ‘-’, file descriptor N is closed. If N is not specified,
the standard input (file descriptor 0) is used.
The operator
is used similarly to duplicate output file descriptors. If N is not
specified, the standard output (file descriptor 1) is used. If the
digits in WORD do not specify a file descriptor open for output, a
-redirection error occurs. If WORD evaluates to '-', file descriptor N
+redirection error occurs. If WORD evaluates to ‘-’, file descriptor N
is closed. As a special case, if N is omitted, and WORD does not expand
-to one or more digits or '-', the standard output and standard error are
+to one or more digits or ‘-’, the standard output and standard error are
redirected as described previously.
3.6.9 Moving File Descriptors
3. Redirections are performed as described above (*note
Redirections::).
- 4. The text after the '=' in each variable assignment undergoes tilde
+ 4. The text after the ‘=’ in each variable assignment undergoes tilde
expansion, parameter expansion, command substitution, arithmetic
expansion, and quote removal before being assigned to the variable.
invoked.
3. If the name is neither a shell function nor a builtin, and contains
- no slashes, Bash searches each element of '$PATH' for a directory
+ no slashes, Bash searches each element of ‘$PATH’ for a directory
containing an executable file by that name. Bash uses a hash table
to remember the full pathnames of executable files to avoid
- multiple 'PATH' searches (see the description of 'hash' in *note
+ multiple ‘PATH’ searches (see the description of ‘hash’ in *note
Bourne Shell Builtins::). A full search of the directories in
- '$PATH' is performed only if the command is not found in the hash
+ ‘$PATH’ is performed only if the command is not found in the hash
table. If the search is unsuccessful, the shell searches for a
- defined shell function named 'command_not_found_handle'. If that
+ defined shell function named ‘command_not_found_handle’. If that
function exists, it is invoked in a separate execution environment
with the original command and the original command's arguments as
its arguments, and the function's exit status becomes the exit
5. If this execution fails because the file is not in executable
format, and the file is not a directory, it is assumed to be a
- "shell script" and the shell executes it as described in *note
+ “shell script” and the shell executes it as described in *note
Shell Scripts::.
6. If the command was not begun asynchronously, the shell waits for
3.7.3 Command Execution Environment
-----------------------------------
-The shell has an "execution environment", which consists of the
+The shell has an “execution environment”, which consists of the
following:
- * open files inherited by the shell at invocation, as modified by
- redirections supplied to the 'exec' builtin
+ • open files inherited by the shell at invocation, as modified by
+ redirections supplied to the ‘exec’ builtin
- * the current working directory as set by 'cd', 'pushd', or 'popd',
+ • the current working directory as set by ‘cd’, ‘pushd’, or ‘popd’,
or inherited by the shell at invocation
- * the file creation mode mask as set by 'umask' or inherited from the
+ • the file creation mode mask as set by ‘umask’ or inherited from the
shell's parent
- * current traps set by 'trap'
+ • current traps set by ‘trap’
- * shell parameters that are set by variable assignment or with 'set'
+ • shell parameters that are set by variable assignment or with ‘set’
or inherited from the shell's parent in the environment
- * shell functions defined during execution or inherited from the
+ • shell functions defined during execution or inherited from the
shell's parent in the environment
- * options enabled at invocation (either by default or with
- command-line arguments) or by 'set'
+ • options enabled at invocation (either by default or with
+ command-line arguments) or by ‘set’
- * options enabled by 'shopt' (*note The Shopt Builtin::)
+ • options enabled by ‘shopt’ (*note The Shopt Builtin::)
- * shell aliases defined with 'alias' (*note Aliases::)
+ • shell aliases defined with ‘alias’ (*note Aliases::)
- * various process IDs, including those of background jobs (*note
- Lists::), the value of '$$', and the value of '$PPID'
+ • various process IDs, including those of background jobs (*note
+ Lists::), the value of ‘$$’, and the value of ‘$PPID’
When a simple command other than a builtin or shell function is to be
executed, it is invoked in a separate execution environment that
consists of the following. Unless otherwise noted, the values are
inherited from the shell.
- * the shell's open files, plus any modifications and additions
+ • the shell's open files, plus any modifications and additions
specified by redirections to the command
- * the current working directory
+ • the current working directory
- * the file creation mode mask
+ • the file creation mode mask
- * shell variables and functions marked for export, along with
+ • shell variables and functions marked for export, along with
variables exported for the command, passed in the environment
(*note Environment::)
- * traps caught by the shell are reset to the values inherited from
+ • traps caught by the shell are reset to the values inherited from
the shell's parent, and traps ignored by the shell are ignored
A command invoked in this separate environment cannot affect the
shell's execution environment.
- A "subshell" is a copy of the shell process.
+ A “subshell” is a copy of the shell process.
Command substitution, commands grouped with parentheses, and
asynchronous commands are invoked in a subshell environment that is a
are also executed in a subshell environment. Changes made to the
subshell environment cannot affect the shell's execution environment.
- Subshells spawned to execute command substitutions inherit the value
-of the '-e' option from the parent shell. When not in POSIX mode, Bash
-clears the '-e' option in such subshells.
+ When the shell is in POSIX mode, subshells spawned to execute command
+substitutions inherit the value of the ‘-e’ option from the parent
+shell. When not in POSIX mode, Bash clears the ‘-e’ option in such
+subshells See the description of the ‘inherit_errexit’ shell option
+(*note Bash Builtins::) for how to control this behavior when not in
+POSIX mode.
- If a command is followed by a '&' and job control is not active, the
-default standard input for the command is the empty file '/dev/null'.
+ If a command is followed by a ‘&’ and job control is not active, the
+default standard input for the command is the empty file ‘/dev/null’.
Otherwise, the invoked command inherits the file descriptors of the
calling shell as modified by redirections.
-----------------
When a program is invoked it is given an array of strings called the
-"environment". This is a list of name-value pairs, of the form
-'name=value'.
+“environment”. This is a list of name-value pairs, of the form
+‘name=value’.
Bash provides several ways to manipulate the environment. On
invocation, the shell scans its own environment and creates a parameter
-for each name found, automatically marking it for 'export' to child
-processes. Executed commands inherit the environment. The 'export' and
-'declare -x' commands allow parameters and functions to be added to and
+for each name found, automatically marking it for ‘export’ to child
+processes. Executed commands inherit the environment. The ‘export’ and
+‘declare -x’ commands allow parameters and functions to be added to and
deleted from the environment. If the value of a parameter in the
environment is modified, the new value becomes part of the environment,
replacing the old. The environment inherited by any executed command
consists of the shell's initial environment, whose values may be
-modified in the shell, less any pairs removed by the 'unset' and 'export
--n' commands, plus any additions via the 'export' and 'declare -x'
+modified in the shell, less any pairs removed by the ‘unset’ and ‘export
+-n’ commands, plus any additions via the ‘export’ and ‘declare -x’
commands.
The environment for any simple command or function may be augmented
*note Shell Parameters::. These assignment statements affect only the
environment seen by that command.
- If the '-k' option is set (*note The Set Builtin::), then all
+ If the ‘-k’ option is set (*note The Set Builtin::), then all
parameter assignments are placed in the environment for a command, not
just those that precede the command name.
- When Bash invokes an external command, the variable '$_' is set to
+ When Bash invokes an external command, the variable ‘$_’ is set to
the full pathname of the command and passed to that command in its
environment.
-----------------
The exit status of an executed command is the value returned by the
-'waitpid' system call or equivalent function. Exit statuses fall
+‘waitpid’ system call or equivalent function. Exit statuses fall
between 0 and 255, though, as explained below, the shell may use values
above 125 specially. Exit statuses from shell builtins and compound
commands are also limited to this range. Under certain circumstances,
-------------
When Bash is interactive, in the absence of any traps, it ignores
-'SIGTERM' (so that 'kill 0' does not kill an interactive shell), and
-'SIGINT' is caught and handled (so that the 'wait' builtin is
-interruptible). When Bash receives a 'SIGINT', it breaks out of any
-executing loops. In all cases, Bash ignores 'SIGQUIT'. If job control
-is in effect (*note Job Control::), Bash ignores 'SIGTTIN', 'SIGTTOU',
-and 'SIGTSTP'.
+‘SIGTERM’ (so that ‘kill 0’ does not kill an interactive shell), and
+‘SIGINT’ is caught and handled (so that the ‘wait’ builtin is
+interruptible). When Bash receives a ‘SIGINT’, it breaks out of any
+executing loops. In all cases, Bash ignores ‘SIGQUIT’. If job control
+is in effect (*note Job Control::), Bash ignores ‘SIGTTIN’, ‘SIGTTOU’,
+and ‘SIGTSTP’.
Non-builtin commands started by Bash have signal handlers set to the
values inherited by the shell from its parent. When job control is not
-in effect, asynchronous commands ignore 'SIGINT' and 'SIGQUIT' in
+in effect, asynchronous commands ignore ‘SIGINT’ and ‘SIGQUIT’ in
addition to these inherited handlers. Commands run as a result of
command substitution ignore the keyboard-generated job control signals
-'SIGTTIN', 'SIGTTOU', and 'SIGTSTP'.
+‘SIGTTIN’, ‘SIGTTOU’, and ‘SIGTSTP’.
- The shell exits by default upon receipt of a 'SIGHUP'. Before
-exiting, an interactive shell resends the 'SIGHUP' to all jobs, running
-or stopped. Stopped jobs are sent 'SIGCONT' to ensure that they receive
-the 'SIGHUP'. To prevent the shell from sending the 'SIGHUP' signal to
+ The shell exits by default upon receipt of a ‘SIGHUP’. Before
+exiting, an interactive shell resends the ‘SIGHUP’ to all jobs, running
+or stopped. Stopped jobs are sent ‘SIGCONT’ to ensure that they receive
+the ‘SIGHUP’. To prevent the shell from sending the ‘SIGHUP’ signal to
a particular job, it should be removed from the jobs table with the
-'disown' builtin (*note Job Control Builtins::) or marked to not receive
-'SIGHUP' using 'disown -h'.
+‘disown’ builtin (*note Job Control Builtins::) or marked to not receive
+‘SIGHUP’ using ‘disown -h’.
- If the 'huponexit' shell option has been set with 'shopt' (*note The
-Shopt Builtin::), Bash sends a 'SIGHUP' to all jobs when an interactive
+ If the ‘huponexit’ shell option has been set with ‘shopt’ (*note The
+Shopt Builtin::), Bash sends a ‘SIGHUP’ to all jobs when an interactive
login shell exits.
If Bash is waiting for a command to complete and receives a signal
for which a trap has been set, the trap will not be executed until the
command completes. When Bash is waiting for an asynchronous command via
-the 'wait' builtin, the reception of a signal for which a trap has been
-set will cause the 'wait' builtin to return immediately with an exit
+the ‘wait’ builtin, the reception of a signal for which a trap has been
+set will cause the ‘wait’ builtin to return immediately with an exit
status greater than 128, immediately after which the trap is executed.
When job control is not enabled, and Bash is waiting for a foreground
command to complete, the shell receives keyboard-generated signals such
-as 'SIGINT' (usually generated by '^C') that users commonly intend to
+as ‘SIGINT’ (usually generated by ‘^C’) that users commonly intend to
send to that command. This happens because the shell and the command
-are in the same process group as the terminal, and '^C' sends 'SIGINT'
+are in the same process group as the terminal, and ‘^C’ sends ‘SIGINT’
to all processes in that process group. See *note Job Control::, for a
more in-depth discussion of process groups.
When Bash is running without job control enabled and receives
-'SIGINT' while waiting for a foreground command, it waits until that
+‘SIGINT’ while waiting for a foreground command, it waits until that
foreground command terminates and then decides what to do about the
-'SIGINT':
+‘SIGINT’:
- 1. If the command terminates due to the 'SIGINT', Bash concludes that
- the user meant to end the entire script, and acts on the 'SIGINT'
- (e.g., by running a 'SIGINT' trap or exiting itself);
+ 1. If the command terminates due to the ‘SIGINT’, Bash concludes that
+ the user meant to end the entire script, and acts on the ‘SIGINT’
+ (e.g., by running a ‘SIGINT’ trap or exiting itself);
- 2. If the pipeline does not terminate due to 'SIGINT', the program
- handled the 'SIGINT' itself and did not treat it as a fatal signal.
- In that case, Bash does not treat 'SIGINT' as a fatal signal,
- either, instead assuming that the 'SIGINT' was used as part of the
- program's normal operation (e.g., 'emacs' uses it to abort editing
+ 2. If the pipeline does not terminate due to ‘SIGINT’, the program
+ handled the ‘SIGINT’ itself and did not treat it as a fatal signal.
+ In that case, Bash does not treat ‘SIGINT’ as a fatal signal,
+ either, instead assuming that the ‘SIGINT’ was used as part of the
+ program's normal operation (e.g., ‘emacs’ uses it to abort editing
commands) or deliberately discarded. However, Bash will run any
- trap set on 'SIGINT', as it does with any other trapped signal it
+ trap set on ‘SIGINT’, as it does with any other trapped signal it
receives while it is waiting for the foreground command to
complete, for compatibility.
A shell script is a text file containing shell commands. When such a
file is used as the first non-option argument when invoking Bash, and
-neither the '-c' nor '-s' option is supplied (*note Invoking Bash::),
+neither the ‘-c’ nor ‘-s’ option is supplied (*note Invoking Bash::),
Bash reads and executes commands from the file, then exits. This mode
of operation creates a non-interactive shell. The shell first searches
for the file in the current directory, and looks in the directories in
-'$PATH' if not found there.
+‘$PATH’ if not found there.
- When Bash runs a shell script, it sets the special parameter '0' to
+ When Bash runs a shell script, it sets the special parameter ‘0’ to
the name of the file, rather than the name of the shell, and the
positional parameters are set to the remaining arguments, if any are
given. If no additional arguments are supplied, the positional
parameters are unset.
- A shell script may be made executable by using the 'chmod' command to
+ A shell script may be made executable by using the ‘chmod’ command to
turn on the execute bit. When Bash finds such a file while searching
-the '$PATH' for a command, it creates a new instance of itself to
+the ‘$PATH’ for a command, it creates a new instance of itself to
execute it. In other words, executing
filename ARGUMENTS
is equivalent to executing
bash filename ARGUMENTS
-if 'filename' is an executable shell script. This subshell
+if ‘filename’ is an executable shell script. This subshell
reinitializes itself, so that the effect is as if a new shell had been
invoked to interpret the script, with the exception that the locations
-of commands remembered by the parent (see the description of 'hash' in
+of commands remembered by the parent (see the description of ‘hash’ in
*note Bourne Shell Builtins::) are retained by the child.
Most versions of Unix make this a part of the operating system's
command execution mechanism. If the first line of a script begins with
-the two characters '#!', the remainder of the line specifies an
+the two characters ‘#!’, the remainder of the line specifies an
interpreter for the program and, depending on the operating system, one
or more optional arguments for that interpreter. Thus, you can specify
-Bash, 'awk', Perl, or some other interpreter and write the rest of the
+Bash, ‘awk’, Perl, or some other interpreter and write the rest of the
script file in that language.
The arguments to the interpreter consist of one or more optional
to a maximum of 32 characters, so it's not portable to assume that using
more than one argument will work.
- Bash scripts often begin with '#! /bin/bash' (assuming that Bash has
-been installed in '/bin'), since this ensures that Bash will be used to
+ Bash scripts often begin with ‘#! /bin/bash’ (assuming that Bash has
+been installed in ‘/bin’), since this ensures that Bash will be used to
interpret the script, even if it is executed under another shell. It's
-a common idiom to use 'env' to find 'bash' even if it's been installed
-in another directory: '#!/usr/bin/env bash' will find the first
-occurrence of 'bash' in '$PATH'.
+a common idiom to use ‘env’ to find ‘bash’ even if it's been installed
+in another directory: ‘#!/usr/bin/env bash’ will find the first
+occurrence of ‘bash’ in ‘$PATH’.
\1f
File: bash.info, Node: Shell Builtin Commands, Next: Shell Variables, Prev: Basic Shell Features, Up: Top
Many of the builtins have been extended by POSIX or Bash.
Unless otherwise noted, each builtin command documented as accepting
-options preceded by '-' accepts '--' to signify the end of the options.
-The ':', 'true', 'false', and 'test'/'[' builtins do not accept options
-and do not treat '--' specially. The 'exit', 'logout', 'return',
-'break', 'continue', 'let', and 'shift' builtins accept and process
-arguments beginning with '-' without requiring '--'. Other builtins
+options preceded by ‘-’ accepts ‘--’ to signify the end of the options.
+The ‘:’, ‘true’, ‘false’, and ‘test’/‘[’ builtins do not accept options
+and do not treat ‘--’ specially. The ‘exit’, ‘logout’, ‘return’,
+‘break’, ‘continue’, ‘let’, and ‘shift’ builtins accept and process
+arguments beginning with ‘-’ without requiring ‘--’. Other builtins
that accept arguments but are not specified as accepting options
-interpret arguments beginning with '-' as invalid options and require
-'--' to prevent this interpretation.
+interpret arguments beginning with ‘-’ as invalid options and require
+‘--’ to prevent this interpretation.
\1f
File: bash.info, Node: Bourne Shell Builtins, Next: Bash Builtins, Up: Shell Builtin Commands
Shell. These commands are implemented as specified by the POSIX
standard.
-': (a colon)'
+‘: (a colon)’
: [ARGUMENTS]
Do nothing beyond expanding ARGUMENTS and performing redirections.
The return status is zero.
-'. (a period)'
+‘. (a period)’
. FILENAME [ARGUMENTS]
Read and execute commands from the FILENAME argument in the current
- shell context. If FILENAME does not contain a slash, the 'PATH'
+ shell context. If FILENAME does not contain a slash, the ‘PATH’
variable is used to find FILENAME, but FILENAME does not need to be
executable. When Bash is not in POSIX mode, it searches the
- current directory if FILENAME is not found in '$PATH'. If any
+ current directory if FILENAME is not found in ‘$PATH’. If any
ARGUMENTS are supplied, they become the positional parameters when
FILENAME is executed. Otherwise the positional parameters are
- unchanged. If the '-T' option is enabled, '.' inherits any trap on
- 'DEBUG'; if it is not, any 'DEBUG' trap string is saved and
- restored around the call to '.', and '.' unsets the 'DEBUG' trap
- while it executes. If '-T' is not set, and the sourced file
- changes the 'DEBUG' trap, the new value is retained when '.'
+ unchanged. If the ‘-T’ option is enabled, ‘.’ inherits any trap on
+ ‘DEBUG’; if it is not, any ‘DEBUG’ trap string is saved and
+ restored around the call to ‘.’, and ‘.’ unsets the ‘DEBUG’ trap
+ while it executes. If ‘-T’ is not set, and the sourced file
+ changes the ‘DEBUG’ trap, the new value is retained when ‘.’
completes. The return status is the exit status of the last
command executed, or zero if no commands are executed. If FILENAME
is not found, or cannot be read, the return status is non-zero.
- This builtin is equivalent to 'source'.
+ This builtin is equivalent to ‘source’.
-'break'
+‘break’
break [N]
- Exit from a 'for', 'while', 'until', or 'select' loop. If N is
+ Exit from a ‘for’, ‘while’, ‘until’, or ‘select’ loop. If N is
supplied, the Nth enclosing loop is exited. N must be greater than
or equal to 1. The return status is zero unless N is not greater
than or equal to 1.
-'cd'
+‘cd’
cd [-L|[-P [-e]]] [-@] [DIRECTORY]
Change the current working directory to DIRECTORY. If DIRECTORY is
- not supplied, the value of the 'HOME' shell variable is used. If
- the shell variable 'CDPATH' exists, it is used as a search path:
- each directory name in 'CDPATH' is searched for DIRECTORY, with
- alternative directory names in 'CDPATH' separated by a colon (':').
- If DIRECTORY begins with a slash, 'CDPATH' is not used.
-
- The '-P' option means to not follow symbolic links: symbolic links
- are resolved while 'cd' is traversing DIRECTORY and before
- processing an instance of '..' in DIRECTORY.
-
- By default, or when the '-L' option is supplied, symbolic links in
- DIRECTORY are resolved after 'cd' processes an instance of '..' in
+ not supplied, the value of the ‘HOME’ shell variable is used. If
+ the shell variable ‘CDPATH’ exists, ‘cd’ uses it as a search path:
+ ‘cd’ searches each directory name in ‘CDPATH’ for DIRECTORY, with
+ alternative directory names in ‘CDPATH’ separated by a colon (‘:’).
+ If DIRECTORY begins with a slash, ‘CDPATH’ is not used.
+
+ The ‘-P’ option means to not follow symbolic links: symbolic links
+ are resolved while ‘cd’ is traversing DIRECTORY and before
+ processing an instance of ‘..’ in DIRECTORY.
+
+ By default, or when the ‘-L’ option is supplied, symbolic links in
+ DIRECTORY are resolved after ‘cd’ processes an instance of ‘..’ in
DIRECTORY.
- If '..' appears in DIRECTORY, it is processed by removing the
+ If ‘..’ appears in DIRECTORY, it is processed by removing the
immediately preceding pathname component, back to a slash or the
beginning of DIRECTORY.
- If the '-e' option is supplied with '-P' and the current working
+ If the ‘-e’ option is supplied with ‘-P’ and the current working
directory cannot be successfully determined after a successful
- directory change, 'cd' will return an unsuccessful status.
+ directory change, ‘cd’ will return an unsuccessful status.
- On systems that support it, the '-@' option presents the extended
+ On systems that support it, the ‘-@’ option presents the extended
attributes associated with a file as a directory.
- If DIRECTORY is '-', it is converted to '$OLDPWD' before the
+ If DIRECTORY is ‘-’, it is converted to ‘$OLDPWD’ before the
directory change is attempted.
- If a non-empty directory name from 'CDPATH' is used, or if '-' is
+ If a non-empty directory name from ‘CDPATH’ is used, or if ‘-’ is
the first argument, and the directory change is successful, the
absolute pathname of the new working directory is written to the
standard output.
- If the directory change is successful, 'cd' sets the value of the
- 'PWD' environment variable to the new directory name, and sets the
- 'OLDPWD' environment variable to the value of the current working
+ If the directory change is successful, ‘cd’ sets the value of the
+ ‘PWD’ environment variable to the new directory name, and sets the
+ ‘OLDPWD’ environment variable to the value of the current working
directory before the change.
The return status is zero if the directory is successfully changed,
non-zero otherwise.
-'continue'
+‘continue’
continue [N]
- Resume the next iteration of an enclosing 'for', 'while', 'until',
- or 'select' loop. If N is supplied, the execution of the Nth
+ Resume the next iteration of an enclosing ‘for’, ‘while’, ‘until’,
+ or ‘select’ loop. If N is supplied, the execution of the Nth
enclosing loop is resumed. N must be greater than or equal to 1.
The return status is zero unless N is not greater than or equal to
1.
-'eval'
+‘eval’
eval [ARGUMENTS]
The arguments are concatenated together into a single command,
which is then read and executed, and its exit status returned as
- the exit status of 'eval'. If there are no arguments or only empty
+ the exit status of ‘eval’. If there are no arguments or only empty
arguments, the return status is zero.
-'exec'
+‘exec’
exec [-cl] [-a NAME] [COMMAND [ARGUMENTS]]
If COMMAND is supplied, it replaces the shell without creating a
- new process. If the '-l' option is supplied, the shell places a
+ new process. If the ‘-l’ option is supplied, the shell places a
dash at the beginning of the zeroth argument passed to COMMAND.
- This is what the 'login' program does. The '-c' option causes
- COMMAND to be executed with an empty environment. If '-a' is
+ This is what the ‘login’ program does. The ‘-c’ option causes
+ COMMAND to be executed with an empty environment. If ‘-a’ is
supplied, the shell passes NAME as the zeroth argument to COMMAND.
If COMMAND cannot be executed for some reason, a non-interactive
- shell exits, unless the 'execfail' shell option is enabled. In
+ shell exits, unless the ‘execfail’ shell option is enabled. In
that case, it returns failure. An interactive shell returns
failure if the file cannot be executed. A subshell exits
- unconditionally if 'exec' fails. If no COMMAND is specified,
+ unconditionally if ‘exec’ fails. If no COMMAND is specified,
redirections may be used to affect the current shell environment.
If there are no redirection errors, the return status is zero;
otherwise the return status is non-zero.
-'exit'
+‘exit’
exit [N]
Exit the shell, returning a status of N to the shell's parent. If
N is omitted, the exit status is that of the last command executed.
- Any trap on 'EXIT' is executed before the shell terminates.
+ Any trap on ‘EXIT’ is executed before the shell terminates.
-'export'
+‘export’
export [-fn] [-p] [NAME[=VALUE]]
Mark each NAME to be passed to child processes in the environment.
- If the '-f' option is supplied, the NAMEs refer to shell functions;
- otherwise the names refer to shell variables. The '-n' option
+ If the ‘-f’ option is supplied, the NAMEs refer to shell functions;
+ otherwise the names refer to shell variables. The ‘-n’ option
means to no longer mark each NAME for export. If no NAMEs are
- supplied, or if the '-p' option is given, a list of names of all
- exported variables is displayed. The '-p' option displays output
+ supplied, or if the ‘-p’ option is given, a list of names of all
+ exported variables is displayed. The ‘-p’ option displays output
in a form that may be reused as input. If a variable name is
followed by =VALUE, the value of the variable is set to VALUE.
The return status is zero unless an invalid option is supplied, one
- of the names is not a valid shell variable name, or '-f' is
+ of the names is not a valid shell variable name, or ‘-f’ is
supplied with a name that is not a shell function.
-'false'
+‘false’
false
Does nothing, returns a non-zero status.
-'getopts'
+‘getopts’
getopts OPTSTRING NAME [ARG ...]
- 'getopts' is used by shell scripts to parse positional parameters.
+ ‘getopts’ is used by shell scripts to parse positional parameters.
OPTSTRING contains the option characters to be recognized; if a
character is followed by a colon, the option is expected to have an
argument, which should be separated from it by whitespace. The
- colon (':') and question mark ('?') may not be used as option
- characters. Each time it is invoked, 'getopts' places the next
+ colon (‘:’) and question mark (‘?’) may not be used as option
+ characters. Each time it is invoked, ‘getopts’ places the next
option in the shell variable NAME, initializing NAME if it does not
exist, and the index of the next argument to be processed into the
- variable 'OPTIND'. 'OPTIND' is initialized to 1 each time the
+ variable ‘OPTIND’. ‘OPTIND’ is initialized to 1 each time the
shell or a shell script is invoked. When an option requires an
- argument, 'getopts' places that argument into the variable
- 'OPTARG'. The shell does not reset 'OPTIND' automatically; it must
- be manually reset between multiple calls to 'getopts' within the
+ argument, ‘getopts’ places that argument into the variable
+ ‘OPTARG’. The shell does not reset ‘OPTIND’ automatically; it must
+ be manually reset between multiple calls to ‘getopts’ within the
same shell invocation if a new set of parameters is to be used.
- When the end of options is encountered, 'getopts' exits with a
- return value greater than zero. 'OPTIND' is set to the index of
- the first non-option argument, and NAME is set to '?'.
+ When the end of options is encountered, ‘getopts’ exits with a
+ return value greater than zero. ‘OPTIND’ is set to the index of
+ the first non-option argument, and NAME is set to ‘?’.
- 'getopts' normally parses the positional parameters, but if more
- arguments are supplied as ARG values, 'getopts' parses those
+ ‘getopts’ normally parses the positional parameters, but if more
+ arguments are supplied as ARG values, ‘getopts’ parses those
instead.
- 'getopts' can report errors in two ways. If the first character of
+ ‘getopts’ can report errors in two ways. If the first character of
OPTSTRING is a colon, SILENT error reporting is used. In normal
operation, diagnostic messages are printed when invalid options or
- missing option arguments are encountered. If the variable 'OPTERR'
+ missing option arguments are encountered. If the variable ‘OPTERR’
is set to 0, no error messages will be displayed, even if the first
- character of 'optstring' is not a colon.
+ character of ‘optstring’ is not a colon.
- If an invalid option is seen, 'getopts' places '?' into NAME and,
- if not silent, prints an error message and unsets 'OPTARG'. If
- 'getopts' is silent, the option character found is placed in
- 'OPTARG' and no diagnostic message is printed.
+ If ‘getopts’ detects an invalid option, it places ‘?’ into NAME
+ and, if not silent, prints an error message and unsets ‘OPTARG’.
+ If ‘getopts’ is silent, it assigns the option character found to
+ ‘OPTARG’ and does not print a diagnostic message.
- If a required argument is not found, and 'getopts' is not silent, a
- question mark ('?') is placed in NAME, 'OPTARG' is unset, and a
- diagnostic message is printed. If 'getopts' is silent, then a
- colon (':') is placed in NAME and 'OPTARG' is set to the option
- character found.
+ If a required argument is not found, and ‘getopts’ is not silent,
+ it sets the value of NAME to a question mark (‘?’), unsets
+ ‘OPTARG’, and prints a diagnostic message. If ‘getopts’ is silent,
+ it sets the value of NAME to a colon (‘:’), and sets ‘OPTARG’ to
+ the option character found.
-'hash'
+‘hash’
hash [-r] [-p FILENAME] [-dt] [NAME]
- Each time 'hash' is invoked, it remembers the full filenames of the
+ Each time ‘hash’ is invoked, it remembers the full filenames of the
commands specified as NAME arguments, so they need not be searched
for on subsequent invocations. The commands are found by searching
- through the directories listed in '$PATH'. Any
- previously-remembered filename is discarded. The '-p' option
+ through the directories listed in ‘$PATH’. Any
+ previously-remembered filename is discarded. The ‘-p’ option
inhibits the path search, and FILENAME is used as the location of
- NAME. The '-r' option causes the shell to forget all remembered
- locations. Assigning to the 'PATH' variable also clears all hashed
- filenames. The '-d' option causes the shell to forget the
- remembered location of each NAME. If the '-t' option is supplied,
+ NAME. The ‘-r’ option causes the shell to forget all remembered
+ locations. Assigning to the ‘PATH’ variable also clears all hashed
+ filenames. The ‘-d’ option causes the shell to forget the
+ remembered location of each NAME. If the ‘-t’ option is supplied,
the full pathname to which each NAME corresponds is printed. If
- multiple NAME arguments are supplied with '-t', the NAME is printed
- before the hashed full pathname. The '-l' option causes output to
+ multiple NAME arguments are supplied with ‘-t’, the NAME is printed
+ before the hashed full pathname. The ‘-l’ option causes output to
be displayed in a format that may be reused as input. If no
- arguments are given, or if only '-l' is supplied, information about
- remembered commands is printed. The '-t', '-d', and '-p' options
+ arguments are given, or if only ‘-l’ is supplied, information about
+ remembered commands is printed. The ‘-t’, ‘-d’, and ‘-p’ options
(the options that act on the NAME arguments) are mutually
exclusive. Only one will be active. If more than one is supplied,
- '-t' has higher priority than '-p', and both are higher priority
- than '-d'. The return status is zero unless a NAME is not found or
+ ‘-t’ has higher priority than ‘-p’, and both are higher priority
+ than ‘-d’. The return status is zero unless a NAME is not found or
an invalid option is supplied.
-'pwd'
+‘pwd’
pwd [-LP]
Print the absolute pathname of the current working directory. If
- the '-P' option is supplied, the pathname printed will not contain
- symbolic links. If the '-L' option is supplied, the pathname
+ the ‘-P’ option is supplied, the pathname printed will not contain
+ symbolic links. If the ‘-L’ option is supplied, the pathname
printed may contain symbolic links. The return status is zero
unless an error is encountered while determining the name of the
current directory or an invalid option is supplied.
-'readonly'
+‘readonly’
readonly [-aAf] [-p] [NAME[=VALUE]] ...
Mark each NAME as readonly. The values of these names may not be
- changed by subsequent assignment. If the '-f' option is supplied,
- each NAME refers to a shell function. The '-a' option means each
- NAME refers to an indexed array variable; the '-A' option means
+ changed by subsequent assignment. If the ‘-f’ option is supplied,
+ each NAME refers to a shell function. The ‘-a’ option means each
+ NAME refers to an indexed array variable; the ‘-A’ option means
each NAME refers to an associative array variable. If both options
- are supplied, '-A' takes precedence. If no NAME arguments are
- given, or if the '-p' option is supplied, a list of all readonly
+ are supplied, ‘-A’ takes precedence. If no NAME arguments are
+ given, or if the ‘-p’ option is supplied, a list of all readonly
names is printed. The other options may be used to restrict the
- output to a subset of the set of readonly names. The '-p' option
+ output to a subset of the set of readonly names. The ‘-p’ option
causes output to be displayed in a format that may be reused as
input. If a variable name is followed by =VALUE, the value of the
variable is set to VALUE. The return status is zero unless an
invalid option is supplied, one of the NAME arguments is not a
- valid shell variable or function name, or the '-f' option is
+ valid shell variable or function name, or the ‘-f’ option is
supplied with a name that is not a shell function.
-'return'
+‘return’
return [N]
Cause a shell function to stop executing and return the value N to
its caller. If N is not supplied, the return value is the exit
- status of the last command executed in the function. If 'return'
+ status of the last command executed in the function. If ‘return’
is executed by a trap handler, the last command used to determine
the status is the last command executed before the trap handler.
- If 'return' is executed during a 'DEBUG' trap, the last command
+ If ‘return’ is executed during a ‘DEBUG’ trap, the last command
used to determine the status is the last command executed by the
- trap handler before 'return' was invoked. 'return' may also be
- used to terminate execution of a script being executed with the '.'
- ('source') builtin, returning either N or the exit status of the
+ trap handler before ‘return’ was invoked. ‘return’ may also be
+ used to terminate execution of a script being executed with the ‘.’
+ (‘source’) builtin, returning either N or the exit status of the
last command executed within the script as the exit status of the
script. If N is supplied, the return value is its least
- significant 8 bits. Any command associated with the 'RETURN' trap
+ significant 8 bits. Any command associated with the ‘RETURN’ trap
is executed before execution resumes after the function or script.
- The return status is non-zero if 'return' is supplied a non-numeric
+ The return status is non-zero if ‘return’ is supplied a non-numeric
argument or is used outside a function and not during the execution
- of a script by '.' or 'source'.
+ of a script by ‘.’ or ‘source’.
-'shift'
+‘shift’
shift [N]
Shift the positional parameters to the left by N. The positional
- parameters from N+1 ... '$#' are renamed to '$1' ... '$#'-N.
- Parameters represented by the numbers '$#' down to '$#'-N+1 are
- unset. N must be a non-negative number less than or equal to '$#'.
- If N is zero or greater than '$#', the positional parameters are
+ parameters from N+1 ... ‘$#’ are renamed to ‘$1’ ... ‘$#’-N.
+ Parameters represented by the numbers ‘$#’ down to ‘$#’-N+1 are
+ unset. N must be a non-negative number less than or equal to ‘$#’.
+ If N is zero or greater than ‘$#’, the positional parameters are
not changed. If N is not supplied, it is assumed to be 1. The
- return status is zero unless N is greater than '$#' or less than
+ return status is zero unless N is greater than ‘$#’ or less than
zero, non-zero otherwise.
-'test'
-'['
+‘test’
+‘[’
test EXPR
Evaluate a conditional expression EXPR and return a status of 0
(true) or 1 (false). Each operator and operand must be a separate
argument. Expressions are composed of the primaries described
- below in *note Bash Conditional Expressions::. 'test' does not
+ below in *note Bash Conditional Expressions::. ‘test’ does not
accept any options, nor does it accept and ignore an argument of
- '--' as signifying the end of options.
+ ‘--’ as signifying the end of options.
- When the '[' form is used, the last argument to the command must be
- a ']'.
+ When the ‘[’ form is used, the last argument to the command must be
+ a ‘]’.
Expressions may be combined using the following operators, listed
in decreasing order of precedence. The evaluation depends on the
number of arguments; see below. Operator precedence is used when
there are five or more arguments.
- '! EXPR'
+ ‘! EXPR’
True if EXPR is false.
- '( EXPR )'
+ ‘( EXPR )’
Returns the value of EXPR. This may be used to override the
normal precedence of operators.
- 'EXPR1 -a EXPR2'
+ ‘EXPR1 -a EXPR2’
True if both EXPR1 and EXPR2 are true.
- 'EXPR1 -o EXPR2'
+ ‘EXPR1 -o EXPR2’
True if either EXPR1 or EXPR2 is true.
- The 'test' and '[' builtins evaluate conditional expressions using
+ The ‘test’ and ‘[’ builtins evaluate conditional expressions using
a set of rules based on the number of arguments.
0 arguments
null.
2 arguments
- If the first argument is '!', the expression is true if and
+ If the first argument is ‘!’, the expression is true if and
only if the second argument is null. If the first argument is
one of the unary conditional operators (*note Bash Conditional
Expressions::), the expression is true if the unary test is
operators (*note Bash Conditional Expressions::), the
result of the expression is the result of the binary test
using the first and third arguments as operands. The
- '-a' and '-o' operators are considered binary operators
+ ‘-a’ and ‘-o’ operators are considered binary operators
when there are three arguments.
- 2. If the first argument is '!', the value is the negation
+ 2. If the first argument is ‘!’, the value is the negation
of the two-argument test using the second and third
arguments.
- 3. If the first argument is exactly '(' and the third
- argument is exactly ')', the result is the one-argument
+ 3. If the first argument is exactly ‘(’ and the third
+ argument is exactly ‘)’, the result is the one-argument
test of the second argument.
4. Otherwise, the expression is false.
4 arguments
The following conditions are applied in the order listed.
- 1. If the first argument is '!', the result is the negation
+ 1. If the first argument is ‘!’, the result is the negation
of the three-argument expression composed of the
remaining arguments.
- 2. If the first argument is exactly '(' and the fourth
- argument is exactly ')', the result is the two-argument
+ 2. If the first argument is exactly ‘(’ and the fourth
+ argument is exactly ‘)’, the result is the two-argument
test of the second and third arguments.
3. Otherwise, the expression is parsed and evaluated
according to precedence using the rules listed above.
The expression is parsed and evaluated according to precedence
using the rules listed above.
- If the shell is not in POSIX mode, when used with 'test' or '[',
- the '<' and '>' operators sort lexicographically using ASCII
- ordering. If the shell is in POSIX mode, these operators use the
- current locale.
+ If the shell is in POSIX mode, or if the expression is part of the
+ ‘[[’ command, the ‘<’ and ‘>’ operators sort using the current
+ locale. If the shell is not in POSIX mode, the ‘test’ and ‘[’
+ commands sort lexicographically using ASCII ordering.
The historical operator-precedence parsing with 4 or more arguments
can lead to ambiguities when it encounters strings that look like
- primaries. The POSIX standard has deprecated the '-a' and '-o'
+ primaries. The POSIX standard has deprecated the ‘-a’ and ‘-o’
primaries and enclosing expressions within parentheses. Scripts
should no longer use them. It's much more reliable to restrict
- test invocations to a single primary, and to replace uses of '-a'
- and '-o' with the shell's '&&' and '||' list operators. For
+ test invocations to a single primary, and to replace uses of ‘-a’
+ and ‘-o’ with the shell's ‘&&’ and ‘||’ list operators. For
example, use
test -n string1 && test -n string2
test -n string1 -a -n string2
-'times'
+‘times’
times
Print out the user and system times used by the shell and its
children. The return status is zero.
-'trap'
+‘trap’
trap [-Plp] [ACTION] [SIGSPEC ...]
The ACTION is a command that is read and executed when the shell
receives signal SIGSPEC. If ACTION is absent (and there is a
- single SIGSPEC) or equal to '-', each specified signal's
+ single SIGSPEC) or equal to ‘-’, each specified signal's
disposition is reset to the value it had when the shell was
started. If ACTION is the null string, then the signal specified
by each SIGSPEC is ignored by the shell and commands it invokes.
- If no arguments are supplied, 'trap' prints the actions associated
- with each trapped signal as a set of 'trap' commands that can be
+ If no arguments are supplied, ‘trap’ prints the actions associated
+ with each trapped signal as a set of ‘trap’ commands that can be
reused as shell input to restore the current signal dispositions.
- If ACTION is not present and '-p' has been supplied, 'trap'
+ If ACTION is not present and ‘-p’ has been supplied, ‘trap’
displays the trap commands associated with each SIGSPEC, or, if no
- SIGSPECs are supplied, for all trapped signals, as a set of 'trap'
+ SIGSPECs are supplied, for all trapped signals, as a set of ‘trap’
commands that can be reused as shell input to restore the current
- signal dispositions. The '-P' option behaves similarly, but
+ signal dispositions. The ‘-P’ option behaves similarly, but
displays only the actions associated with each SIGSPEC argument.
- '-P' requires at least one SIGSPEC argument. The '-P' or '-p'
- options to 'trap' may be used in a subshell environment (e.g.,
- command substitution) and, as long as they are used before 'trap'
+ ‘-P’ requires at least one SIGSPEC argument. The ‘-P’ or ‘-p’
+ options to ‘trap’ may be used in a subshell environment (e.g.,
+ command substitution) and, as long as they are used before ‘trap’
is used to change a signal's handling, will display the state of
its parent's traps.
- The '-l' option causes 'trap' to print a list of signal names and
+ The ‘-l’ option causes ‘trap’ to print a list of signal names and
their corresponding numbers. Each SIGSPEC is either a signal name
or a signal number. Signal names are case insensitive and the
- 'SIG' prefix is optional.
+ ‘SIG’ prefix is optional.
- If a SIGSPEC is '0' or 'EXIT', ACTION is executed when the shell
- exits. If a SIGSPEC is 'DEBUG', ACTION is executed before every
- simple command, 'for' command, 'case' command, 'select' command, ((
- arithmetic command, [[ conditional command, arithmetic 'for'
+ If a SIGSPEC is ‘0’ or ‘EXIT’, ACTION is executed when the shell
+ exits. If a SIGSPEC is ‘DEBUG’, ACTION is executed before every
+ simple command, ‘for’ command, ‘case’ command, ‘select’ command, ((
+ arithmetic command, [[ conditional command, arithmetic ‘for’
command, and before the first command executes in a shell function.
- Refer to the description of the 'extdebug' option to the 'shopt'
+ Refer to the description of the ‘extdebug’ option to the ‘shopt’
builtin (*note The Shopt Builtin::) for details of its effect on
- the 'DEBUG' trap. If a SIGSPEC is 'RETURN', ACTION is executed
- each time a shell function or a script executed with the '.' or
- 'source' builtins finishes executing.
+ the ‘DEBUG’ trap. If a SIGSPEC is ‘RETURN’, ACTION is executed
+ each time a shell function or a script executed with the ‘.’ or
+ ‘source’ builtins finishes executing.
- If a SIGSPEC is 'ERR', ACTION is executed whenever a pipeline
+ If a SIGSPEC is ‘ERR’, ACTION is executed whenever a pipeline
(which may consist of a single simple command), a list, or a
compound command returns a non-zero exit status, subject to the
- following conditions. The 'ERR' trap is not executed if the failed
+ following conditions. The ‘ERR’ trap is not executed if the failed
command is part of the command list immediately following an
- 'until' or 'while' keyword, part of the test following the 'if' or
- 'elif' reserved words, part of a command executed in a '&&' or '||'
- list except the command following the final '&&' or '||', any
+ ‘until’ or ‘while’ keyword, part of the test following the ‘if’ or
+ ‘elif’ reserved words, part of a command executed in a ‘&&’ or ‘||’
+ list except the command following the final ‘&&’ or ‘||’, any
command in a pipeline but the last, or if the command's return
- status is being inverted using '!'. These are the same conditions
- obeyed by the 'errexit' ('-e') option.
+ status is being inverted using ‘!’. These are the same conditions
+ obeyed by the ‘errexit’ (‘-e’) option.
Signals ignored upon entry to a non-interactive shell cannot be
trapped or reset. Interactive shells permit trapping signals
The return status is zero unless a SIGSPEC does not specify a valid
signal.
-'true'
+‘true’
true
Does nothing, returns a 0 status.
-'umask'
+‘umask’
umask [-p] [-S] [MODE]
Set the shell process's file creation mask to MODE. If MODE begins
with a digit, it is interpreted as an octal number; if not, it is
interpreted as a symbolic mode mask similar to that accepted by the
- 'chmod' command. If MODE is omitted, the current value of the mask
- is printed. If the '-S' option is supplied without a MODE
- argument, the mask is printed in a symbolic format. If the '-p'
+ ‘chmod’ command. If MODE is omitted, the current value of the mask
+ is printed. If the ‘-S’ option is supplied without a MODE
+ argument, the mask is printed in a symbolic format. If the ‘-p’
option is supplied, and MODE is omitted, the output is in a form
that may be reused as input. The return status is zero if the mode
is successfully changed or if no MODE argument is supplied, and
non-zero otherwise.
Note that when the mode is interpreted as an octal number, each
- number of the umask is subtracted from '7'. Thus, a umask of '022'
- results in permissions of '755'.
+ number of the umask is subtracted from ‘7’. Thus, a umask of ‘022’
+ results in permissions of ‘755’.
-'unset'
+‘unset’
unset [-fnv] [NAME]
- Remove each variable or function NAME. If the '-v' option is
+ Remove each variable or function NAME. If the ‘-v’ option is
given, each NAME refers to a shell variable and that variable is
- removed. If the '-f' option is given, the NAMEs refer to shell
- functions, and the function definition is removed. If the '-n'
- option is supplied, and NAME is a variable with the 'nameref'
+ removed. If the ‘-f’ option is given, the NAMEs refer to shell
+ functions, and the function definition is removed. If the ‘-n’
+ option is supplied, and NAME is a variable with the ‘nameref’
attribute, NAME will be unset rather than the variable it
- references. '-n' has no effect if the '-f' option is supplied. If
+ references. ‘-n’ has no effect if the ‘-f’ option is supplied. If
no options are supplied, each NAME refers to a variable; if there
is no variable by that name, a function with that name, if any, is
unset. Readonly variables and functions may not be unset. Some
extended in Bash. Some of these commands are specified in the POSIX
standard.
-'alias'
+‘alias’
alias [-p] [NAME[=VALUE] ...]
- Without arguments or with the '-p' option, 'alias' prints the list
+ Without arguments or with the ‘-p’ option, ‘alias’ prints the list
of aliases on the standard output in a form that allows them to be
reused as input. If arguments are supplied, an alias is defined
for each NAME whose VALUE is given. If no VALUE is given, the name
and value of the alias is printed. Aliases are described in *note
Aliases::.
-'bind'
+‘bind’
bind [-m KEYMAP] [-lpsvPSVX]
bind [-m KEYMAP] [-q FUNCTION] [-u FUNCTION] [-r KEYSEQ]
bind [-m KEYMAP] -f FILENAME
macro, or set a Readline variable. Each non-option argument is a
command as it would appear in a Readline initialization file (*note
Readline Init File::), but each binding or command must be passed
- as a separate argument; e.g., '"\C-x\C-r":re-read-init-file'.
+ as a separate argument; e.g., ‘"\C-x\C-r":re-read-init-file’.
Options, if supplied, have the following meanings:
- '-m KEYMAP'
+ ‘-m KEYMAP’
Use KEYMAP as the keymap to be affected by the subsequent
- bindings. Acceptable KEYMAP names are 'emacs',
- 'emacs-standard', 'emacs-meta', 'emacs-ctlx', 'vi', 'vi-move',
- 'vi-command', and 'vi-insert'. 'vi' is equivalent to
- 'vi-command' ('vi-move' is also a synonym); 'emacs' is
- equivalent to 'emacs-standard'.
+ bindings. Acceptable KEYMAP names are ‘emacs’,
+ ‘emacs-standard’, ‘emacs-meta’, ‘emacs-ctlx’, ‘vi’, ‘vi-move’,
+ ‘vi-command’, and ‘vi-insert’. ‘vi’ is equivalent to
+ ‘vi-command’ (‘vi-move’ is also a synonym); ‘emacs’ is
+ equivalent to ‘emacs-standard’.
- '-l'
+ ‘-l’
List the names of all Readline functions.
- '-p'
+ ‘-p’
Display Readline function names and bindings in such a way
- that they can be used as an argument to a subsequent 'bind'
+ that they can be used as an argument to a subsequent ‘bind’
command or in a Readline initialization file.
- '-P'
+ ‘-P’
List current Readline function names and bindings.
- '-v'
+ ‘-v’
Display Readline variable names and values in such a way that
- they can be used as an argument to a subsequent 'bind' command
+ they can be used as an argument to a subsequent ‘bind’ command
or in a Readline initialization file.
- '-V'
+ ‘-V’
List current Readline variable names and values.
- '-s'
+ ‘-s’
Display Readline key sequences bound to macros and the strings
they output in such a way that they can be used as an argument
- to a subsequent 'bind' command or in a Readline initialization
+ to a subsequent ‘bind’ command or in a Readline initialization
file.
- '-S'
+ ‘-S’
Display Readline key sequences bound to macros and the strings
they output.
- '-f FILENAME'
+ ‘-f FILENAME’
Read key bindings from FILENAME.
- '-q FUNCTION'
+ ‘-q FUNCTION’
Query about which keys invoke the named FUNCTION.
- '-u FUNCTION'
+ ‘-u FUNCTION’
Unbind all keys bound to the named FUNCTION.
- '-r KEYSEQ'
+ ‘-r KEYSEQ’
Remove any current binding for KEYSEQ.
- '-x KEYSEQ:SHELL-COMMAND'
+ ‘-x KEYSEQ:SHELL-COMMAND’
Cause SHELL-COMMAND to be executed whenever KEYSEQ is entered.
The separator between KEYSEQ and SHELL-COMMAND is either
whitespace or a colon optionally followed by whitespace. If
before saving it. Since the entire key binding expression
must be a single argument, it should be enclosed in quotes.
When SHELL-COMMAND is executed, the shell sets the
- 'READLINE_LINE' variable to the contents of the Readline line
- buffer and the 'READLINE_POINT' and 'READLINE_MARK' variables
+ ‘READLINE_LINE’ variable to the contents of the Readline line
+ buffer and the ‘READLINE_POINT’ and ‘READLINE_MARK’ variables
to the current location of the insertion point and the saved
insertion point (the MARK), respectively. The shell assigns
any numeric argument the user supplied to the
- 'READLINE_ARGUMENT' variable. If there was no argument, that
+ ‘READLINE_ARGUMENT’ variable. If there was no argument, that
variable is not set. If the executed command changes the
- value of any of 'READLINE_LINE', 'READLINE_POINT', or
- 'READLINE_MARK', those new values will be reflected in the
+ value of any of ‘READLINE_LINE’, ‘READLINE_POINT’, or
+ ‘READLINE_MARK’, those new values will be reflected in the
editing state.
- '-X'
+ ‘-X’
List all key sequences bound to shell commands and the
associated commands in a format that can be reused as an
- argument to a subsequent 'bind' command.
+ argument to a subsequent ‘bind’ command.
The return status is zero unless an invalid option is supplied or
an error occurs.
-'builtin'
+‘builtin’
builtin [SHELL-BUILTIN [ARGS]]
Run a shell builtin, passing it ARGS, and return its exit status.
the function. The return status is non-zero if SHELL-BUILTIN is
not a shell builtin command.
-'caller'
+‘caller’
caller [EXPR]
Returns the context of any active subroutine call (a shell function
- or a script executed with the '.' or 'source' builtins).
+ or a script executed with the ‘.’ or ‘source’ builtins).
- Without EXPR, 'caller' displays the line number and source filename
+ Without EXPR, ‘caller’ displays the line number and source filename
of the current subroutine call. If a non-negative integer is
- supplied as EXPR, 'caller' displays the line number, subroutine
+ supplied as EXPR, ‘caller’ displays the line number, subroutine
name, and source file corresponding to that position in the current
execution call stack. This extra information may be used, for
example, to print a stack trace. The current frame is frame 0.
subroutine call or EXPR does not correspond to a valid position in
the call stack.
-'command'
+‘command’
command [-pVv] COMMAND [ARGUMENTS ...]
Runs COMMAND with ARGUMENTS ignoring any shell function named
COMMAND. Only shell builtin commands or commands found by
- searching the 'PATH' are executed. If there is a shell function
- named 'ls', running 'command ls' within the function will execute
- the external command 'ls' instead of calling the function
- recursively. The '-p' option means to use a default value for
- 'PATH' that is guaranteed to find all of the standard utilities.
+ searching the ‘PATH’ are executed. If there is a shell function
+ named ‘ls’, running ‘command ls’ within the function will execute
+ the external command ‘ls’ instead of calling the function
+ recursively. The ‘-p’ option means to use a default value for
+ ‘PATH’ that is guaranteed to find all of the standard utilities.
The return status in this case is 127 if COMMAND cannot be found or
an error occurred, and the exit status of COMMAND otherwise.
- If either the '-V' or '-v' option is supplied, a description of
- COMMAND is printed. The '-v' option causes a single word
+ If either the ‘-V’ or ‘-v’ option is supplied, a description of
+ COMMAND is printed. The ‘-v’ option causes a single word
indicating the command or file name used to invoke COMMAND to be
- displayed; the '-V' option produces a more verbose description. In
+ displayed; the ‘-V’ option produces a more verbose description. In
this case, the return status is zero if COMMAND is found, and
non-zero if not.
-'declare'
+‘declare’
declare [-aAfFgiIlnrtux] [-p] [NAME[=VALUE] ...]
Declare variables and give them attributes. If no NAMEs are given,
then display the values of variables instead.
- The '-p' option will display the attributes and values of each
- NAME. When '-p' is used with NAME arguments, additional options,
- other than '-f' and '-F', are ignored.
+ The ‘-p’ option will display the attributes and values of each
+ NAME. When ‘-p’ is used with NAME arguments, additional options,
+ other than ‘-f’ and ‘-F’, are ignored.
- When '-p' is supplied without NAME arguments, 'declare' will
+ When ‘-p’ is supplied without NAME arguments, ‘declare’ will
display the attributes and values of all variables having the
attributes specified by the additional options. If no other
- options are supplied with '-p', 'declare' will display the
- attributes and values of all shell variables. The '-f' option will
+ options are supplied with ‘-p’, ‘declare’ will display the
+ attributes and values of all shell variables. The ‘-f’ option will
restrict the display to shell functions.
- The '-F' option inhibits the display of function definitions; only
- the function name and attributes are printed. If the 'extdebug'
- shell option is enabled using 'shopt' (*note The Shopt Builtin::),
+ The ‘-F’ option inhibits the display of function definitions; only
+ the function name and attributes are printed. If the ‘extdebug’
+ shell option is enabled using ‘shopt’ (*note The Shopt Builtin::),
the source file name and line number where each NAME is defined are
- displayed as well. '-F' implies '-f'.
+ displayed as well. ‘-F’ implies ‘-f’.
- The '-g' option forces variables to be created or modified at the
- global scope, even when 'declare' is executed in a shell function.
+ The ‘-g’ option forces variables to be created or modified at the
+ global scope, even when ‘declare’ is executed in a shell function.
It is ignored in all other cases.
- The '-I' option causes local variables to inherit the attributes
- (except the 'nameref' attribute) and value of any existing variable
+ The ‘-I’ option causes local variables to inherit the attributes
+ (except the ‘nameref’ attribute) and value of any existing variable
with the same NAME at a surrounding scope. If there is no existing
variable, the local variable is initially unset.
The following options can be used to restrict output to variables
with the specified attributes or to give variables attributes:
- '-a'
+ ‘-a’
Each NAME is an indexed array variable (*note Arrays::).
- '-A'
+ ‘-A’
Each NAME is an associative array variable (*note Arrays::).
- '-f'
+ ‘-f’
Use function names only.
- '-i'
+ ‘-i’
The variable is to be treated as an integer; arithmetic
evaluation (*note Shell Arithmetic::) is performed when the
variable is assigned a value.
- '-l'
+ ‘-l’
When the variable is assigned a value, all upper-case
characters are converted to lower-case. The upper-case
attribute is disabled.
- '-n'
- Give each NAME the 'nameref' attribute, making it a name
+ ‘-n’
+ Give each NAME the ‘nameref’ attribute, making it a name
reference to another variable. That other variable is defined
by the value of NAME. All references, assignments, and
attribute modifications to NAME, except for those using or
- changing the '-n' attribute itself, are performed on the
+ changing the ‘-n’ attribute itself, are performed on the
variable referenced by NAME's value. The nameref attribute
cannot be applied to array variables.
- '-r'
+ ‘-r’
Make NAMEs readonly. These names cannot then be assigned
values by subsequent assignment statements or unset.
- '-t'
- Give each NAME the 'trace' attribute. Traced functions
- inherit the 'DEBUG' and 'RETURN' traps from the calling shell.
+ ‘-t’
+ Give each NAME the ‘trace’ attribute. Traced functions
+ inherit the ‘DEBUG’ and ‘RETURN’ traps from the calling shell.
The trace attribute has no special meaning for variables.
- '-u'
+ ‘-u’
When the variable is assigned a value, all lower-case
characters are converted to upper-case. The lower-case
attribute is disabled.
- '-x'
+ ‘-x’
Mark each NAME for export to subsequent commands via the
environment.
- Using '+' instead of '-' turns off the attribute instead, with the
- exceptions that '+a' and '+A' may not be used to destroy array
- variables and '+r' will not remove the readonly attribute. When
- used in a function, 'declare' makes each NAME local, as with the
- 'local' command, unless the '-g' option is used. If a variable
+ Using ‘+’ instead of ‘-’ turns off the attribute instead, with the
+ exceptions that ‘+a’ and ‘+A’ may not be used to destroy array
+ variables and ‘+r’ will not remove the readonly attribute. When
+ used in a function, ‘declare’ makes each NAME local, as with the
+ ‘local’ command, unless the ‘-g’ option is used. If a variable
name is followed by =VALUE, the value of the variable is set to
VALUE.
- When using '-a' or '-A' and the compound assignment syntax to
+ When using ‘-a’ or ‘-A’ and the compound assignment syntax to
create array variables, additional attributes do not take effect
until subsequent assignments.
The return status is zero unless an invalid option is encountered,
- an attempt is made to define a function using '-f foo=bar', an
+ an attempt is made to define a function using ‘-f foo=bar’, an
attempt is made to assign a value to a readonly variable, an
attempt is made to assign a value to an array variable without
using the compound assignment syntax (*note Arrays::), one of the
NAMEs is not a valid shell variable name, an attempt is made to
turn off readonly status for a readonly variable, an attempt is
made to turn off array status for an array variable, or an attempt
- is made to display a non-existent function with '-f'.
+ is made to display a non-existent function with ‘-f’.
-'echo'
+‘echo’
echo [-neE] [ARG ...]
Output the ARGs, separated by spaces, terminated with a newline.
- The return status is 0 unless a write error occurs. If '-n' is
- specified, the trailing newline is suppressed. If the '-e' option
+ The return status is 0 unless a write error occurs. If ‘-n’ is
+ specified, the trailing newline is suppressed. If the ‘-e’ option
is given, interpretation of the following backslash-escaped
- characters is enabled. The '-E' option disables the interpretation
+ characters is enabled. The ‘-E’ option disables the interpretation
of these escape characters, even on systems where they are
- interpreted by default. The 'xpg_echo' shell option may be used to
- dynamically determine whether or not 'echo' interprets any options
- and expands these escape characters by default. 'echo' does not
- interpret '--' to mean the end of options.
+ interpreted by default. The ‘xpg_echo’ shell option may be used to
+ dynamically determine whether or not ‘echo’ interprets any options
+ and expands these escape characters by default. ‘echo’ does not
+ interpret ‘--’ to mean the end of options.
- 'echo' interprets the following escape sequences:
- '\a'
+ ‘echo’ interprets the following escape sequences:
+ ‘\a’
alert (bell)
- '\b'
+ ‘\b’
backspace
- '\c'
+ ‘\c’
suppress further output
- '\e'
- '\E'
+ ‘\e’
+ ‘\E’
escape
- '\f'
+ ‘\f’
form feed
- '\n'
+ ‘\n’
new line
- '\r'
+ ‘\r’
carriage return
- '\t'
+ ‘\t’
horizontal tab
- '\v'
+ ‘\v’
vertical tab
- '\\'
+ ‘\\’
backslash
- '\0NNN'
+ ‘\0NNN’
the eight-bit character whose value is the octal value NNN
(zero to three octal digits)
- '\xHH'
+ ‘\xHH’
the eight-bit character whose value is the hexadecimal value
HH (one or two hex digits)
- '\uHHHH'
+ ‘\uHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHH (one to four hex digits)
- '\UHHHHHHHH'
+ ‘\UHHHHHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHHHHHH (one to eight hex digits)
-'enable'
+‘enable’
enable [-a] [-dnps] [-f FILENAME] [NAME ...]
Enable and disable builtin shell commands. Disabling a builtin
allows a disk command which has the same name as a shell builtin to
be executed without specifying a full pathname, even though the
- shell normally searches for builtins before disk commands. If '-n'
+ shell normally searches for builtins before disk commands. If ‘-n’
is used, the NAMEs become disabled. Otherwise NAMEs are enabled.
- For example, to use the 'test' binary found via '$PATH' instead of
- the shell builtin version, type 'enable -n test'.
+ For example, to use the ‘test’ binary found via ‘$PATH’ instead of
+ the shell builtin version, type ‘enable -n test’.
- If the '-p' option is supplied, or no NAME arguments appear, a list
+ If the ‘-p’ option is supplied, or no NAME arguments appear, a list
of shell builtins is printed. With no other arguments, the list
- consists of all enabled shell builtins. The '-a' option means to
+ consists of all enabled shell builtins. The ‘-a’ option means to
list each builtin with an indication of whether or not it is
enabled.
- The '-f' option means to load the new builtin command NAME from
+ The ‘-f’ option means to load the new builtin command NAME from
shared object FILENAME, on systems that support dynamic loading.
- Bash will use the value of the 'BASH_LOADABLES_PATH' variable as a
+ Bash will use the value of the ‘BASH_LOADABLES_PATH’ variable as a
colon-separated list of directories in which to search for
FILENAME, if FILENAME does not contain a slash. The default is
system-dependent, and may include "." to force a search of the
- current directory. The '-d' option will delete a builtin loaded
- with '-f'.
+ current directory. The ‘-d’ option will delete a builtin loaded
+ with ‘-f’.
If there are no options, a list of the shell builtins is displayed.
- The '-s' option restricts 'enable' to the POSIX special builtins.
- If '-s' is used with '-f', the new builtin becomes a special
+ The ‘-s’ option restricts ‘enable’ to the POSIX special builtins.
+ If ‘-s’ is used with ‘-f’, the new builtin becomes a special
builtin (*note Special Builtins::).
If no options are supplied and a NAME is not a shell builtin,
- 'enable' will attempt to load NAME from a shared object named NAME,
- as if the command were 'enable -f NAME NAME'.
+ ‘enable’ will attempt to load NAME from a shared object named NAME,
+ as if the command were ‘enable -f NAME NAME’.
The return status is zero unless a NAME is not a shell builtin or
there is an error loading a new builtin from a shared object.
-'help'
+‘help’
help [-dms] [PATTERN]
Display helpful information about builtin commands. If PATTERN is
- specified, 'help' gives detailed help on all commands matching
+ specified, ‘help’ gives detailed help on all commands matching
PATTERN, otherwise a list of the builtins is printed.
Options, if supplied, have the following meanings:
- '-d'
+ ‘-d’
Display a short description of each PATTERN
- '-m'
+ ‘-m’
Display the description of each PATTERN in a manpage-like
format
- '-s'
+ ‘-s’
Display only a short usage synopsis for each PATTERN
The return status is zero unless no command matches PATTERN.
-'let'
+‘let’
let EXPRESSION [EXPRESSION ...]
- The 'let' builtin allows arithmetic to be performed on shell
+ The ‘let’ builtin allows arithmetic to be performed on shell
variables. Each EXPRESSION is evaluated according to the rules
given below in *note Shell Arithmetic::. If the last EXPRESSION
- evaluates to 0, 'let' returns 1; otherwise 0 is returned.
+ evaluates to 0, ‘let’ returns 1; otherwise 0 is returned.
-'local'
+‘local’
local [OPTION] NAME[=VALUE] ...
For each argument, a local variable named NAME is created, and
assigned VALUE. The OPTION can be any of the options accepted by
- 'declare'. 'local' can only be used within a function; it makes
+ ‘declare’. ‘local’ can only be used within a function; it makes
the variable NAME have a visible scope restricted to that function
- and its children. If NAME is '-', the set of shell options is made
- local to the function in which 'local' is invoked: shell options
- changed using the 'set' builtin inside the function after the call
- to 'local' are restored to their original values when the function
- returns. The restore is effected as if a series of 'set' commands
+ and its children. If NAME is ‘-’, the set of shell options is made
+ local to the function in which ‘local’ is invoked: shell options
+ changed using the ‘set’ builtin inside the function after the call
+ to ‘local’ are restored to their original values when the function
+ returns. The restore is effected as if a series of ‘set’ commands
were executed to restore the values that were in place before the
- function. The return status is zero unless 'local' is used outside
+ function. The return status is zero unless ‘local’ is used outside
a function, an invalid NAME is supplied, or NAME is a readonly
variable.
-'logout'
+‘logout’
logout [N]
Exit a login shell, returning a status of N to the shell's parent.
-'mapfile'
+‘mapfile’
mapfile [-d DELIM] [-n COUNT] [-O ORIGIN] [-s COUNT]
[-t] [-u FD] [-C CALLBACK] [-c QUANTUM] [ARRAY]
Read lines from the standard input into the indexed array variable
- ARRAY, or from file descriptor FD if the '-u' option is supplied.
- The variable 'MAPFILE' is the default ARRAY. Options, if supplied,
+ ARRAY, or from file descriptor FD if the ‘-u’ option is supplied.
+ The variable ‘MAPFILE’ is the default ARRAY. Options, if supplied,
have the following meanings:
- '-d'
+ ‘-d’
The first character of DELIM is used to terminate each input
line, rather than newline. If DELIM is the empty string,
- 'mapfile' will terminate a line when it reads a NUL character.
- '-n'
+ ‘mapfile’ will terminate a line when it reads a NUL character.
+ ‘-n’
Copy at most COUNT lines. If COUNT is 0, all lines are
copied.
- '-O'
+ ‘-O’
Begin assigning to ARRAY at index ORIGIN. The default index
is 0.
- '-s'
+ ‘-s’
Discard the first COUNT lines read.
- '-t'
+ ‘-t’
Remove a trailing DELIM (default newline) from each line read.
- '-u'
+ ‘-u’
Read lines from file descriptor FD instead of the standard
input.
- '-C'
- Evaluate CALLBACK each time QUANTUM lines are read. The '-c'
+ ‘-C’
+ Evaluate CALLBACK each time QUANTUM lines are read. The ‘-c’
option specifies QUANTUM.
- '-c'
+ ‘-c’
Specify the number of lines read between each call to
CALLBACK.
- If '-C' is specified without '-c', the default quantum is 5000.
+ If ‘-C’ is specified without ‘-c’, the default quantum is 5000.
When CALLBACK is evaluated, it is supplied the index of the next
array element to be assigned and the line to be assigned to that
element as additional arguments. CALLBACK is evaluated after the
line is read but before the array element is assigned.
- If not supplied with an explicit origin, 'mapfile' will clear ARRAY
+ If not supplied with an explicit origin, ‘mapfile’ will clear ARRAY
before assigning to it.
- 'mapfile' returns successfully unless an invalid option or option
+ ‘mapfile’ returns successfully unless an invalid option or option
argument is supplied, ARRAY is invalid or unassignable, or ARRAY is
not an indexed array.
-'printf'
+‘printf’
printf [-v VAR] FORMAT [ARGUMENTS]
Write the formatted ARGUMENTS to the standard output under the
- control of the FORMAT. The '-v' option causes the output to be
+ control of the FORMAT. The ‘-v’ option causes the output to be
assigned to the variable VAR rather than being printed to the
standard output.
output, character escape sequences, which are converted and copied
to the standard output, and format specifications, each of which
causes printing of the next successive ARGUMENT. In addition to
- the standard 'printf(3)' format characters 'csndiouxXeEfFgGaA',
- 'printf' interprets the following additional format specifiers:
+ the standard ‘printf(3)’ format characters ‘csndiouxXeEfFgGaA’,
+ ‘printf’ interprets the following additional format specifiers:
- '%b'
- Causes 'printf' to expand backslash escape sequences in the
- corresponding ARGUMENT in the same way as 'echo -e' (*note
+ ‘%b’
+ Causes ‘printf’ to expand backslash escape sequences in the
+ corresponding ARGUMENT in the same way as ‘echo -e’ (*note
Bash Builtins::).
- '%q'
- Causes 'printf' to output the corresponding ARGUMENT in a
- format that can be reused as shell input. '%q' and '%Q'P use
+ ‘%q’
+ Causes ‘printf’ to output the corresponding ARGUMENT in a
+ format that can be reused as shell input. ‘%q’ and ‘%Q’P use
the ANSI-C quoting style (*note ANSI-C Quoting::) if any
characters in the argument string require it, and backslash
- quoting otherwise. If the format string uses the 'printf'
+ quoting otherwise. If the format string uses the ‘printf’
ALTERNATE FORM, these two formats quote the argument string
using single quotes.
- '%Q'
- like '%q', but applies any supplied precision to the ARGUMENT
+ ‘%Q’
+ like ‘%q’, but applies any supplied precision to the ARGUMENT
before quoting it.
- '%(DATEFMT)T'
- Causes 'printf' to output the date-time string resulting from
- using DATEFMT as a format string for 'strftime'(3). The
+ ‘%(DATEFMT)T’
+ Causes ‘printf’ to output the date-time string resulting from
+ using DATEFMT as a format string for ‘strftime’(3). The
corresponding ARGUMENT is an integer representing the number
of seconds since the epoch. Two special argument values may
be used: -1 represents the current time, and -2 represents the
time the shell was invoked. If no argument is specified,
conversion behaves as if -1 had been given. This is an
- exception to the usual 'printf' behavior.
+ exception to the usual ‘printf’ behavior.
The %b, %q, and %T format specifiers all use the field width and
precision arguments from the format specification and write that
success, non-zero if an invalid option is supplied or a write or
assignment error occurs.
-'read'
+‘read’
read [-Eers] [-a ANAME] [-d DELIM] [-i TEXT] [-n NCHARS]
[-N NCHARS] [-p PROMPT] [-t TIMEOUT] [-u FD] [NAME ...]
One line is read from the standard input, or from the file
- descriptor FD supplied as an argument to the '-u' option, split
+ descriptor FD supplied as an argument to the ‘-u’ option, split
into words as described above in *note Word Splitting::, and the
first word is assigned to the first NAME, the second word to the
second NAME, and so on. If there are more words than names, the
remaining words and their intervening delimiters are assigned to
the last NAME. If there are fewer words read from the input stream
than names, the remaining names are assigned empty values. The
- characters in the value of the 'IFS' variable are used to split the
+ characters in the value of the ‘IFS’ variable are used to split the
line into words using the same rules the shell uses for expansion
(described above in *note Word Splitting::). The backslash
- character '\' may be used to remove any special meaning for the
+ character ‘\’ may be used to remove any special meaning for the
next character read and for line continuation.
Options, if supplied, have the following meanings:
- '-a ANAME'
+ ‘-a ANAME’
The words are assigned to sequential indices of the array
variable ANAME, starting at 0. All elements are removed from
ANAME before the assignment. Other NAME arguments are
ignored.
- '-d DELIM'
+ ‘-d DELIM’
The first character of DELIM is used to terminate the input
line, rather than newline. If DELIM is the empty string,
- 'read' will terminate a line when it reads a NUL character.
+ ‘read’ will terminate a line when it reads a NUL character.
- '-e'
+ ‘-e’
Readline (*note Command Line Editing::) is used to obtain the
line. Readline uses the current (or default, if line editing
was not previously active) editing settings, but uses
Readline's default filename completion.
- '-E'
+ ‘-E’
Readline (*note Command Line Editing::) is used to obtain the
line. Readline uses the current (or default, if line editing
was not previously active) editing settings, but uses Bash's
default completion, including programmable completion.
- '-i TEXT'
+ ‘-i TEXT’
If Readline is being used to read the line, TEXT is placed
into the editing buffer before editing begins.
- '-n NCHARS'
- 'read' returns after reading NCHARS characters rather than
+ ‘-n NCHARS’
+ ‘read’ returns after reading NCHARS characters rather than
waiting for a complete line of input, but honors a delimiter
if fewer than NCHARS characters are read before the delimiter.
- '-N NCHARS'
- 'read' returns after reading exactly NCHARS characters rather
+ ‘-N NCHARS’
+ ‘read’ returns after reading exactly NCHARS characters rather
than waiting for a complete line of input, unless EOF is
- encountered or 'read' times out. Delimiter characters
+ encountered or ‘read’ times out. Delimiter characters
encountered in the input are not treated specially and do not
- cause 'read' to return until NCHARS characters are read. The
- result is not split on the characters in 'IFS'; the intent is
+ cause ‘read’ to return until NCHARS characters are read. The
+ result is not split on the characters in ‘IFS’; the intent is
that the variable is assigned exactly the characters read
- (with the exception of backslash; see the '-r' option below).
+ (with the exception of backslash; see the ‘-r’ option below).
- '-p PROMPT'
+ ‘-p PROMPT’
Display PROMPT, without a trailing newline, before attempting
to read any input. The prompt is displayed only if input is
coming from a terminal.
- '-r'
+ ‘-r’
If this option is given, backslash does not act as an escape
character. The backslash is considered to be part of the
line. In particular, a backslash-newline pair may not then be
used as a line continuation.
- '-s'
+ ‘-s’
Silent mode. If input is coming from a terminal, characters
are not echoed.
- '-t TIMEOUT'
- Cause 'read' to time out and return failure if a complete line
+ ‘-t TIMEOUT’
+ Cause ‘read’ to time out and return failure if a complete line
of input (or a specified number of characters) is not read
within TIMEOUT seconds. TIMEOUT may be a decimal number with
a fractional portion following the decimal point. This option
- is only effective if 'read' is reading input from a terminal,
+ is only effective if ‘read’ is reading input from a terminal,
pipe, or other special file; it has no effect when reading
- from regular files. If 'read' times out, 'read' saves any
+ from regular files. If ‘read’ times out, ‘read’ saves any
partial input read into the specified variable NAME. If
- TIMEOUT is 0, 'read' returns immediately, without trying to
+ TIMEOUT is 0, ‘read’ returns immediately, without trying to
read any data. The exit status is 0 if input is available on
the specified file descriptor, or the read will return EOF,
non-zero otherwise. The exit status is greater than 128 if
the timeout is exceeded.
- '-u FD'
+ ‘-u FD’
Read input from file descriptor FD.
+ Other than the case where DELIM is the empty string, ‘read’ ignores
+ any NUL characters in the input.
+
If no NAMEs are supplied, the line read, without the ending
delimiter but otherwise unmodified, is assigned to the variable
- 'REPLY'. The exit status is zero, unless end-of-file is
- encountered, 'read' times out (in which case the status is greater
+ ‘REPLY’. The exit status is zero, unless end-of-file is
+ encountered, ‘read’ times out (in which case the status is greater
than 128), a variable assignment error (such as assigning to a
readonly variable) occurs, or an invalid file descriptor is
- supplied as the argument to '-u'.
+ supplied as the argument to ‘-u’.
-'readarray'
+‘readarray’
readarray [-d DELIM] [-n COUNT] [-O ORIGIN] [-s COUNT]
[-t] [-u FD] [-C CALLBACK] [-c QUANTUM] [ARRAY]
Read lines from the standard input into the indexed array variable
- ARRAY, or from file descriptor FD if the '-u' option is supplied.
+ ARRAY, or from file descriptor FD if the ‘-u’ option is supplied.
- A synonym for 'mapfile'.
+ A synonym for ‘mapfile’.
-'source'
+‘source’
source FILENAME
- A synonym for '.' (*note Bourne Shell Builtins::).
+ A synonym for ‘.’ (*note Bourne Shell Builtins::).
-'type'
+‘type’
type [-afptP] [NAME ...]
For each NAME, indicate how it would be interpreted if used as a
command name.
- If the '-t' option is used, 'type' prints a single word which is
- one of 'alias', 'keyword', 'function', 'builtin', or 'file', if
+ If the ‘-t’ option is used, ‘type’ prints a single word which is
+ one of ‘alias’, ‘keyword’, ‘function’, ‘builtin’, or ‘file’, if
NAME is an alias, shell reserved word, shell function, shell
builtin, or executable disk file, respectively. If the NAME is not
- found, then nothing is printed, and 'type' returns a failure
+ found, then nothing is printed, and ‘type’ returns a failure
status.
- If the '-p' option is used, 'type' either returns the name of the
- executable file that would be found by searching '$PATH', or
- nothing if '-t' would not return 'file'.
+ If the ‘-p’ option is used, ‘type’ either returns the name of the
+ executable file that would be found by searching ‘$PATH’, or
+ nothing if ‘-t’ would not return ‘file’.
- The '-P' option forces a path search for each NAME, even if '-t'
- would not return 'file'.
+ The ‘-P’ option forces a path search for each NAME, even if ‘-t’
+ would not return ‘file’.
- If a NAME is present in the table of hashed commands, options '-p'
- and '-P' print the hashed value, which is not necessarily the file
- that appears first in '$PATH'.
+ If a NAME is present in the table of hashed commands, options ‘-p’
+ and ‘-P’ print the hashed value, which is not necessarily the file
+ that appears first in ‘$PATH’.
- If the '-a' option is used, 'type' returns all of the places that
+ If the ‘-a’ option is used, ‘type’ returns all of the places that
contain a command named NAME. This includes aliases, reserved
- words, functions, and builtins, but the path search options ('-p'
- and '-P') can be supplied to restrict the output to executable
- files. If '-a' is supplied with '-p', 'type' does not look in the
- table of hashed commands, and only performs a 'PATH' search for
+ words, functions, and builtins, but the path search options (‘-p’
+ and ‘-P’) can be supplied to restrict the output to executable
+ files. If ‘-a’ is supplied with ‘-p’, ‘type’ does not look in the
+ table of hashed commands, and only performs a ‘PATH’ search for
NAME.
- If the '-f' option is used, 'type' does not attempt to find shell
- functions, as with the 'command' builtin.
+ If the ‘-f’ option is used, ‘type’ does not attempt to find shell
+ functions, as with the ‘command’ builtin.
The return status is zero if all of the NAMEs are found, non-zero
if any are not found.
-'typeset'
+‘typeset’
typeset [-afFgrxilnrtux] [-p] [NAME[=VALUE] ...]
- The 'typeset' command is supplied for compatibility with the Korn
- shell. It is a synonym for the 'declare' builtin command.
+ The ‘typeset’ command is supplied for compatibility with the Korn
+ shell. It is a synonym for the ‘declare’ builtin command.
-'ulimit'
+‘ulimit’
ulimit [-HS] -a
ulimit [-HS] [-bcdefiklmnpqrstuvxPRT] [LIMIT]
- 'ulimit' provides control over the resources available to processes
+ ‘ulimit’ provides control over the resources available to processes
started by the shell, on systems that allow such control. If an
option is given, it is interpreted as follows:
- '-S'
+ ‘-S’
Change and report the soft limit associated with a resource.
- '-H'
+ ‘-H’
Change and report the hard limit associated with a resource.
- '-a'
+ ‘-a’
All current limits are reported; no limits are set.
- '-b'
+ ‘-b’
The maximum socket buffer size.
- '-c'
+ ‘-c’
The maximum size of core files created.
- '-d'
+ ‘-d’
The maximum size of a process's data segment.
- '-e'
+ ‘-e’
The maximum scheduling priority ("nice").
- '-f'
+ ‘-f’
The maximum size of files written by the shell and its
children.
- '-i'
+ ‘-i’
The maximum number of pending signals.
- '-k'
+ ‘-k’
The maximum number of kqueues that may be allocated.
- '-l'
+ ‘-l’
The maximum size that may be locked into memory.
- '-m'
+ ‘-m’
The maximum resident set size (many systems do not honor this
limit).
- '-n'
+ ‘-n’
The maximum number of open file descriptors (most systems do
not allow this value to be set).
- '-p'
+ ‘-p’
The pipe buffer size.
- '-q'
+ ‘-q’
The maximum number of bytes in POSIX message queues.
- '-r'
+ ‘-r’
The maximum real-time scheduling priority.
- '-s'
+ ‘-s’
The maximum stack size.
- '-t'
+ ‘-t’
The maximum amount of cpu time in seconds.
- '-u'
+ ‘-u’
The maximum number of processes available to a single user.
- '-v'
+ ‘-v’
The maximum amount of virtual memory available to the shell,
and, on some systems, to its children.
- '-x'
+ ‘-x’
The maximum number of file locks.
- '-P'
+ ‘-P’
The maximum number of pseudoterminals.
- '-R'
+ ‘-R’
The maximum time a real-time process can run before blocking,
in microseconds.
- '-T'
+ ‘-T’
The maximum number of threads.
- If LIMIT is given, and the '-a' option is not used, LIMIT is the
+ If LIMIT is given, and the ‘-a’ option is not used, LIMIT is the
new value of the specified resource. The special LIMIT values
- 'hard', 'soft', and 'unlimited' stand for the current hard limit,
+ ‘hard’, ‘soft’, and ‘unlimited’ stand for the current hard limit,
the current soft limit, and no limit, respectively. A hard limit
cannot be increased by a non-root user once it is set; a soft limit
may be increased up to the value of the hard limit. Otherwise, the
current value of the soft limit for the specified resource is
- printed, unless the '-H' option is supplied. When more than one
+ printed, unless the ‘-H’ option is supplied. When more than one
resource is specified, the limit name and unit, if appropriate, are
- printed before the value. When setting new limits, if neither '-H'
- nor '-S' is supplied, both the hard and soft limits are set. If no
- option is given, then '-f' is assumed. Values are in 1024-byte
- increments, except for '-t', which is in seconds; '-R', which is in
- microseconds; '-p', which is in units of 512-byte blocks; '-P',
- '-T', '-b', '-k', '-n' and '-u', which are unscaled values; and,
- when in POSIX Mode (*note Bash POSIX Mode::), '-c' and '-f', which
+ printed before the value. When setting new limits, if neither ‘-H’
+ nor ‘-S’ is supplied, both the hard and soft limits are set. If no
+ option is given, then ‘-f’ is assumed. Values are in 1024-byte
+ increments, except for ‘-t’, which is in seconds; ‘-R’, which is in
+ microseconds; ‘-p’, which is in units of 512-byte blocks; ‘-P’,
+ ‘-T’, ‘-b’, ‘-k’, ‘-n’ and ‘-u’, which are unscaled values; and,
+ when in POSIX Mode (*note Bash POSIX Mode::), ‘-c’ and ‘-f’, which
are in 512-byte increments.
The return status is zero unless an invalid option or argument is
supplied, or an error occurs while setting a new limit.
-'unalias'
+‘unalias’
unalias [-a] [NAME ... ]
- Remove each NAME from the list of aliases. If '-a' is supplied,
+ Remove each NAME from the list of aliases. If ‘-a’ is supplied,
all aliases are removed. Aliases are described in *note Aliases::.
\1f
4.3.1 The Set Builtin
---------------------
-This builtin is so complicated that it deserves its own section. 'set'
+This builtin is so complicated that it deserves its own section. ‘set’
allows you to change the values of shell options and set the positional
parameters, or to display the names and values of shell variables.
-'set'
+‘set’
set [-abefhkmnptuvxBCEHPT] [-o OPTION-NAME] [--] [-] [ARGUMENT ...]
set [+abefhkmnptuvxBCEHPT] [+o OPTION-NAME] [--] [-] [ARGUMENT ...]
set -o
set +o
- If no options or arguments are supplied, 'set' displays the names
+ If no options or arguments are supplied, ‘set’ displays the names
and values of all shell variables and functions, sorted according
to the current locale, in a format that may be reused as input for
setting or resetting the currently-set variables. Read-only
When options are supplied, they set or unset shell attributes.
Options, if specified, have the following meanings:
- '-a'
+ ‘-a’
Each variable or function that is created or modified is given
the export attribute and marked for export to the environment
of subsequent commands.
- '-b'
+ ‘-b’
Cause the status of terminated background jobs to be reported
immediately, rather than before printing the next primary
prompt.
- '-e'
+ ‘-e’
Exit immediately if a pipeline (*note Pipelines::), which may
consist of a single simple command (*note Simple Commands::),
a list (*note Lists::), or a compound command (*note Compound
Commands::) returns a non-zero status. The shell does not
exit if the command that fails is part of the command list
- immediately following a 'while' or 'until' keyword, part of
- the test in an 'if' statement, part of any command executed in
- a '&&' or '||' list except the command following the final
- '&&' or '||', any command in a pipeline but the last, or if
- the command's return status is being inverted with '!'. If a
+ immediately following a ‘while’ or ‘until’ keyword, part of
+ the test in an ‘if’ statement, part of any command executed in
+ a ‘&&’ or ‘||’ list except the command following the final
+ ‘&&’ or ‘||’, any command in a pipeline but the last, or if
+ the command's return status is being inverted with ‘!’. If a
compound command other than a subshell returns a non-zero
- status because a command failed while '-e' was being ignored,
- the shell does not exit. A trap on 'ERR', if set, is executed
+ status because a command failed while ‘-e’ was being ignored,
+ the shell does not exit. A trap on ‘ERR’, if set, is executed
before the shell exits.
This option applies to the shell environment and each subshell
executing all the commands in the subshell.
If a compound command or shell function executes in a context
- where '-e' is being ignored, none of the commands executed
+ where ‘-e’ is being ignored, none of the commands executed
within the compound command or function body will be affected
- by the '-e' setting, even if '-e' is set and a command returns
+ by the ‘-e’ setting, even if ‘-e’ is set and a command returns
a failure status. If a compound command or shell function
- sets '-e' while executing in a context where '-e' is ignored,
+ sets ‘-e’ while executing in a context where ‘-e’ is ignored,
that setting will not have any effect until the compound
command or the command containing the function call completes.
- '-f'
+ ‘-f’
Disable filename expansion (globbing).
- '-h'
+ ‘-h’
Locate and remember (hash) commands as they are looked up for
execution. This option is enabled by default.
- '-k'
+ ‘-k’
All arguments in the form of assignment statements are placed
in the environment for a command, not just those that precede
the command name.
- '-m'
+ ‘-m’
Job control is enabled (*note Job Control::). All processes
run in a separate process group. When a background job
completes, the shell prints a line containing its exit status.
- '-n'
+ ‘-n’
Read commands but do not execute them. This may be used to
check a script for syntax errors. This option is ignored by
interactive shells.
- '-o OPTION-NAME'
+ ‘-o OPTION-NAME’
- Set the option corresponding to OPTION-NAME. If '-o' is
- supplied with no OPTION-NAME, 'set' prints the current shell
- options settings. If '+o' is supplied with no OPTION-NAME,
- 'set' prints a series of 'set' commands to recreate the
+ Set the option corresponding to OPTION-NAME. If ‘-o’ is
+ supplied with no OPTION-NAME, ‘set’ prints the current shell
+ options settings. If ‘+o’ is supplied with no OPTION-NAME,
+ ‘set’ prints a series of ‘set’ commands to recreate the
current option settings on the standard output. Valid option
names are:
- 'allexport'
- Same as '-a'.
+ ‘allexport’
+ Same as ‘-a’.
- 'braceexpand'
- Same as '-B'.
+ ‘braceexpand’
+ Same as ‘-B’.
- 'emacs'
- Use an 'emacs'-style line editing interface (*note
+ ‘emacs’
+ Use an ‘emacs’-style line editing interface (*note
Command Line Editing::). This also affects the editing
- interface used for 'read -e'.
+ interface used for ‘read -e’.
- 'errexit'
- Same as '-e'.
+ ‘errexit’
+ Same as ‘-e’.
- 'errtrace'
- Same as '-E'.
+ ‘errtrace’
+ Same as ‘-E’.
- 'functrace'
- Same as '-T'.
+ ‘functrace’
+ Same as ‘-T’.
- 'hashall'
- Same as '-h'.
+ ‘hashall’
+ Same as ‘-h’.
- 'histexpand'
- Same as '-H'.
+ ‘histexpand’
+ Same as ‘-H’.
- 'history'
+ ‘history’
Enable command history, as described in *note Bash
History Facilities::. This option is on by default in
interactive shells.
- 'ignoreeof'
+ ‘ignoreeof’
An interactive shell will not exit upon reading EOF.
- 'keyword'
- Same as '-k'.
+ ‘keyword’
+ Same as ‘-k’.
- 'monitor'
- Same as '-m'.
+ ‘monitor’
+ Same as ‘-m’.
- 'noclobber'
- Same as '-C'.
+ ‘noclobber’
+ Same as ‘-C’.
- 'noexec'
- Same as '-n'.
+ ‘noexec’
+ Same as ‘-n’.
- 'noglob'
- Same as '-f'.
+ ‘noglob’
+ Same as ‘-f’.
- 'nolog'
+ ‘nolog’
Currently ignored.
- 'notify'
- Same as '-b'.
+ ‘notify’
+ Same as ‘-b’.
- 'nounset'
- Same as '-u'.
+ ‘nounset’
+ Same as ‘-u’.
- 'onecmd'
- Same as '-t'.
+ ‘onecmd’
+ Same as ‘-t’.
- 'physical'
- Same as '-P'.
+ ‘physical’
+ Same as ‘-P’.
- 'pipefail'
+ ‘pipefail’
If set, the return value of a pipeline is the value of
the last (rightmost) command to exit with a non-zero
status, or zero if all commands in the pipeline exit
successfully. This option is disabled by default.
- 'posix'
+ ‘posix’
Change the behavior of Bash where the default operation
differs from the POSIX standard to match the standard
(*note Bash POSIX Mode::). This is intended to make Bash
behave as a strict superset of that standard.
- 'privileged'
- Same as '-p'.
+ ‘privileged’
+ Same as ‘-p’.
- 'verbose'
- Same as '-v'.
+ ‘verbose’
+ Same as ‘-v’.
- 'vi'
- Use a 'vi'-style line editing interface. This also
- affects the editing interface used for 'read -e'.
+ ‘vi’
+ Use a ‘vi’-style line editing interface. This also
+ affects the editing interface used for ‘read -e’.
- 'xtrace'
- Same as '-x'.
+ ‘xtrace’
+ Same as ‘-x’.
- '-p'
- Turn on privileged mode. In this mode, the '$BASH_ENV' and
- '$ENV' files are not processed, shell functions are not
- inherited from the environment, and the 'SHELLOPTS',
- 'BASHOPTS', 'CDPATH' and 'GLOBIGNORE' variables, if they
+ ‘-p’
+ Turn on privileged mode. In this mode, the ‘$BASH_ENV’ and
+ ‘$ENV’ files are not processed, shell functions are not
+ inherited from the environment, and the ‘SHELLOPTS’,
+ ‘BASHOPTS’, ‘CDPATH’ and ‘GLOBIGNORE’ variables, if they
appear in the environment, are ignored. If the shell is
started with the effective user (group) id not equal to the
- real user (group) id, and the '-p' option is not supplied,
+ real user (group) id, and the ‘-p’ option is not supplied,
these actions are taken and the effective user id is set to
- the real user id. If the '-p' option is supplied at startup,
+ the real user id. If the ‘-p’ option is supplied at startup,
the effective user id is not reset. Turning this option off
causes the effective user and group ids to be set to the real
user and group ids.
- '-r'
+ ‘-r’
Enable restricted shell mode (*note The Restricted Shell::).
This option cannot be unset once it has been set.
- '-t'
+ ‘-t’
Exit after reading and executing one command.
- '-u'
+ ‘-u’
Treat unset variables and parameters other than the special
- parameters '@' or '*', or array variables subscripted with '@'
- or '*', as an error when performing parameter expansion. An
+ parameters ‘@’ or ‘*’, or array variables subscripted with ‘@’
+ or ‘*’, as an error when performing parameter expansion. An
error message will be written to the standard error, and a
non-interactive shell will exit.
- '-v'
+ ‘-v’
Print shell input lines as they are read.
- '-x'
- Print a trace of simple commands, 'for' commands, 'case'
- commands, 'select' commands, and arithmetic 'for' commands and
+ ‘-x’
+ Print a trace of simple commands, ‘for’ commands, ‘case’
+ commands, ‘select’ commands, and arithmetic ‘for’ commands and
their arguments or associated word lists to standard error
after they are expanded and before they are executed. The
- shell prints the expanded value of the 'PS4' variable before
+ shell prints the expanded value of the ‘PS4’ variable before
the command and its expanded arguments.
- '-B'
+ ‘-B’
The shell will perform brace expansion (*note Brace
Expansion::). This option is on by default.
- '-C'
- Prevent output redirection using '>', '>&', and '<>' from
+ ‘-C’
+ Prevent output redirection using ‘>’, ‘>&’, and ‘<>’ from
overwriting existing files.
- '-E'
- If set, any trap on 'ERR' is inherited by shell functions,
+ ‘-E’
+ If set, any trap on ‘ERR’ is inherited by shell functions,
command substitutions, and commands executed in a subshell
- environment. The 'ERR' trap is normally not inherited in such
+ environment. The ‘ERR’ trap is normally not inherited in such
cases.
- '-H'
- Enable '!' style history substitution (*note History
+ ‘-H’
+ Enable ‘!’ style history substitution (*note History
Interaction::). This option is on by default for interactive
shells.
- '-P'
+ ‘-P’
If set, do not resolve symbolic links when performing commands
- such as 'cd' which change the current directory. The physical
+ such as ‘cd’ which change the current directory. The physical
directory is used instead. By default, Bash follows the
logical chain of directories when performing commands which
change the current directory.
- For example, if '/usr/sys' is a symbolic link to
- '/usr/local/sys' then:
+ For example, if ‘/usr/sys’ is a symbolic link to
+ ‘/usr/local/sys’ then:
$ cd /usr/sys; echo $PWD
/usr/sys
$ cd ..; pwd
/usr
- If 'set -P' is on, then:
+ If ‘set -P’ is on, then:
$ cd /usr/sys; echo $PWD
/usr/local/sys
$ cd ..; pwd
/usr/local
- '-T'
- If set, any trap on 'DEBUG' and 'RETURN' are inherited by
+ ‘-T’
+ If set, any trap on ‘DEBUG’ and ‘RETURN’ are inherited by
shell functions, command substitutions, and commands executed
- in a subshell environment. The 'DEBUG' and 'RETURN' traps are
+ in a subshell environment. The ‘DEBUG’ and ‘RETURN’ traps are
normally not inherited in such cases.
- '--'
+ ‘--’
If no arguments follow this option, then the positional
parameters are unset. Otherwise, the positional parameters
are set to the ARGUMENTS, even if some of them begin with a
- '-'.
+ ‘-’.
- '-'
+ ‘-’
Signal the end of options, cause all remaining ARGUMENTS to be
- assigned to the positional parameters. The '-x' and '-v'
+ assigned to the positional parameters. The ‘-x’ and ‘-v’
options are turned off. If there are no arguments, the
positional parameters remain unchanged.
- Using '+' rather than '-' causes these options to be turned off.
+ Using ‘+’ rather than ‘-’ causes these options to be turned off.
The options can also be used upon invocation of the shell. The
- current set of options may be found in '$-'.
+ current set of options may be found in ‘$-’.
The remaining N ARGUMENTS are positional parameters and are
- assigned, in order, to '$1', '$2', ... '$N'. The special parameter
- '#' is set to N.
+ assigned, in order, to ‘$1’, ‘$2’, ... ‘$N’. The special parameter
+ ‘#’ is set to N.
The return status is always zero unless an invalid option is
supplied.
This builtin allows you to change additional shell optional behavior.
-'shopt'
+‘shopt’
shopt [-pqsu] [-o] [OPTNAME ...]
Toggle the values of settings controlling optional shell behavior.
- The settings can be either those listed below, or, if the '-o'
- option is used, those available with the '-o' option to the 'set'
+ The settings can be either those listed below, or, if the ‘-o’
+ option is used, those available with the ‘-o’ option to the ‘set’
builtin command (*note The Set Builtin::). With no options, or
- with the '-p' option, a list of all settable options is displayed,
+ with the ‘-p’ option, a list of all settable options is displayed,
with an indication of whether or not each is set; if OPTNAMEs are
- supplied, the output is restricted to those options. The '-p'
+ supplied, the output is restricted to those options. The ‘-p’
option causes output to be displayed in a form that may be reused
as input. Other options have the following meanings:
- '-s'
+ ‘-s’
Enable (set) each OPTNAME.
- '-u'
+ ‘-u’
Disable (unset) each OPTNAME.
- '-q'
+ ‘-q’
Suppresses normal output; the return status indicates whether
the OPTNAME is set or unset. If multiple OPTNAME arguments
- are given with '-q', the return status is zero if all OPTNAMEs
+ are given with ‘-q’, the return status is zero if all OPTNAMEs
are enabled; non-zero otherwise.
- '-o'
+ ‘-o’
Restricts the values of OPTNAME to be those defined for the
- '-o' option to the 'set' builtin (*note The Set Builtin::).
+ ‘-o’ option to the ‘set’ builtin (*note The Set Builtin::).
- If either '-s' or '-u' is used with no OPTNAME arguments, 'shopt'
+ If either ‘-s’ or ‘-u’ is used with no OPTNAME arguments, ‘shopt’
shows only those options which are set or unset, respectively.
- Unless otherwise noted, the 'shopt' options are disabled (off) by
+ Unless otherwise noted, the ‘shopt’ options are disabled (off) by
default.
The return status when listing options is zero if all OPTNAMEs are
the return status is zero unless an OPTNAME is not a valid shell
option.
- The list of 'shopt' options is:
+ The list of ‘shopt’ options is:
- 'array_expand_once'
+ ‘array_expand_once’
If set, the shell suppresses multiple evaluation of
associative and indexed array subscripts during arithmetic
expression evaluation, while executing builtins that can
perform variable assignments, and while executing builtins
that perform array dereferencing.
- 'assoc_expand_once'
- Deprecated; a synonym for 'array_expand_once'.
+ ‘assoc_expand_once’
+ Deprecated; a synonym for ‘array_expand_once’.
- 'autocd'
+ ‘autocd’
If set, a command name that is the name of a directory is
- executed as if it were the argument to the 'cd' command. This
+ executed as if it were the argument to the ‘cd’ command. This
option is only used by interactive shells.
- 'cdable_vars'
- If this is set, an argument to the 'cd' builtin command that
+ ‘cdable_vars’
+ If this is set, an argument to the ‘cd’ builtin command that
is not a directory is assumed to be the name of a variable
whose value is the directory to change to.
- 'cdspell'
+ ‘cdspell’
If set, minor errors in the spelling of a directory component
- in a 'cd' command will be corrected. The errors checked for
+ in a ‘cd’ command will be corrected. The errors checked for
are transposed characters, a missing character, and a
character too many. If a correction is found, the corrected
path is printed, and the command proceeds. This option is
only used by interactive shells.
- 'checkhash'
+ ‘checkhash’
If this is set, Bash checks that a command found in the hash
table exists before trying to execute it. If a hashed command
no longer exists, a normal path search is performed.
- 'checkjobs'
+ ‘checkjobs’
If set, Bash lists the status of any stopped and running jobs
before exiting an interactive shell. If any jobs are running,
this causes the exit to be deferred until a second exit is
Control::). The shell always postpones exiting if any jobs
are stopped.
- 'checkwinsize'
+ ‘checkwinsize’
If set, Bash checks the window size after each external
(non-builtin) command and, if necessary, updates the values of
- 'LINES' and 'COLUMNS'. This option is enabled by default.
+ ‘LINES’ and ‘COLUMNS’. This option is enabled by default.
- 'cmdhist'
+ ‘cmdhist’
If set, Bash attempts to save all lines of a multiple-line
command in the same history entry. This allows easy
re-editing of multi-line commands. This option is enabled by
default, but only has an effect if command history is enabled
(*note Bash History Facilities::).
- 'compat31'
- 'compat32'
- 'compat40'
- 'compat41'
- 'compat42'
- 'compat43'
- 'compat44'
+ ‘compat31’
+ ‘compat32’
+ ‘compat40’
+ ‘compat41’
+ ‘compat42’
+ ‘compat43’
+ ‘compat44’
These control aspects of the shell's compatibility mode (*note
Shell Compatibility Mode::).
- 'complete_fullquote'
+ ‘complete_fullquote’
If set, Bash quotes all shell metacharacters in filenames and
directory names when performing completion. If not set, Bash
removes metacharacters such as the dollar sign from the set of
set by default, which is the default Bash behavior in versions
through 4.2.
- 'direxpand'
+ ‘direxpand’
If set, Bash replaces directory names with the results of word
expansion when performing filename completion. This changes
the contents of the Readline editing buffer. If not set, Bash
attempts to preserve what the user typed.
- 'dirspell'
+ ‘dirspell’
If set, Bash attempts spelling correction on directory names
during word completion if the directory name initially
supplied does not exist.
- 'dotglob'
+ ‘dotglob’
If set, Bash includes filenames beginning with a '.' in the
- results of filename expansion. The filenames '.' and '..'
- must always be matched explicitly, even if 'dotglob' is set.
+ results of filename expansion. The filenames ‘.’ and ‘..’
+ must always be matched explicitly, even if ‘dotglob’ is set.
- 'execfail'
+ ‘execfail’
If this is set, a non-interactive shell will not exit if it
- cannot execute the file specified as an argument to the 'exec'
- builtin command. An interactive shell does not exit if 'exec'
+ cannot execute the file specified as an argument to the ‘exec’
+ builtin command. An interactive shell does not exit if ‘exec’
fails.
- 'expand_aliases'
+ ‘expand_aliases’
If set, aliases are expanded as described below under Aliases,
*note Aliases::. This option is enabled by default for
interactive shells.
- 'extdebug'
+ ‘extdebug’
If set at shell invocation, or in a shell startup file,
arrange to execute the debugger profile before the shell
- starts, identical to the '--debugger' option. If set after
+ starts, identical to the ‘--debugger’ option. If set after
invocation, behavior intended for use by debuggers is enabled:
- 1. The '-F' option to the 'declare' builtin (*note Bash
+ 1. The ‘-F’ option to the ‘declare’ builtin (*note Bash
Builtins::) displays the source file name and line number
corresponding to each function name supplied as an
argument.
- 2. If the command run by the 'DEBUG' trap returns a non-zero
+ 2. If the command run by the ‘DEBUG’ trap returns a non-zero
value, the next command is skipped and not executed.
- 3. If the command run by the 'DEBUG' trap returns a value of
+ 3. If the command run by the ‘DEBUG’ trap returns a value of
2, and the shell is executing in a subroutine (a shell
- function or a shell script executed by the '.' or
- 'source' builtins), the shell simulates a call to
- 'return'.
+ function or a shell script executed by the ‘.’ or
+ ‘source’ builtins), the shell simulates a call to
+ ‘return’.
- 4. 'BASH_ARGC' and 'BASH_ARGV' are updated as described in
+ 4. ‘BASH_ARGC’ and ‘BASH_ARGV’ are updated as described in
their descriptions (*note Bash Variables::).
5. Function tracing is enabled: command substitution, shell
- functions, and subshells invoked with '( COMMAND )'
- inherit the 'DEBUG' and 'RETURN' traps.
+ functions, and subshells invoked with ‘( COMMAND )’
+ inherit the ‘DEBUG’ and ‘RETURN’ traps.
6. Error tracing is enabled: command substitution, shell
- functions, and subshells invoked with '( COMMAND )'
- inherit the 'ERR' trap.
+ functions, and subshells invoked with ‘( COMMAND )’
+ inherit the ‘ERR’ trap.
- 'extglob'
+ ‘extglob’
If set, the extended pattern matching features described above
(*note Pattern Matching::) are enabled.
- 'extquote'
- If set, '$'STRING'' and '$"STRING"' quoting is performed
- within '${PARAMETER}' expansions enclosed in double quotes.
+ ‘extquote’
+ If set, ‘$'STRING'’ and ‘$"STRING"’ quoting is performed
+ within ‘${PARAMETER}’ expansions enclosed in double quotes.
This option is enabled by default.
- 'failglob'
+ ‘failglob’
If set, patterns which fail to match filenames during filename
expansion result in an expansion error.
- 'force_fignore'
- If set, the suffixes specified by the 'FIGNORE' shell variable
+ ‘force_fignore’
+ If set, the suffixes specified by the ‘FIGNORE’ shell variable
cause words to be ignored when performing word completion even
if the ignored words are the only possible completions. *Note
- Bash Variables::, for a description of 'FIGNORE'. This option
+ Bash Variables::, for a description of ‘FIGNORE’. This option
is enabled by default.
- 'globasciiranges'
+ ‘globasciiranges’
If set, range expressions used in pattern matching bracket
expressions (*note Pattern Matching::) behave as if in the
traditional C locale when performing comparisons. That is,
the current locale's collating sequence is not taken into
- account, so 'b' will not collate between 'A' and 'B', and
+ account, so ‘b’ will not collate between ‘A’ and ‘B’, and
upper-case and lower-case ASCII characters will collate
together.
- 'globskipdots'
- If set, filename expansion will never match the filenames '.'
- and '..', even if the pattern begins with a '.'. This option
+ ‘globskipdots’
+ If set, filename expansion will never match the filenames ‘.’
+ and ‘..’, even if the pattern begins with a ‘.’. This option
is enabled by default.
- 'globstar'
- If set, the pattern '**' used in a filename expansion context
+ ‘globstar’
+ If set, the pattern ‘**’ used in a filename expansion context
will match all files and zero or more directories and
- subdirectories. If the pattern is followed by a '/', only
+ subdirectories. If the pattern is followed by a ‘/’, only
directories and subdirectories match.
- 'gnu_errfmt'
+ ‘gnu_errfmt’
If set, shell error messages are written in the standard GNU
error message format.
- 'histappend'
+ ‘histappend’
If set, the history list is appended to the file named by the
- value of the 'HISTFILE' variable when the shell exits, rather
+ value of the ‘HISTFILE’ variable when the shell exits, rather
than overwriting the file.
- 'histreedit'
+ ‘histreedit’
If set, and Readline is being used, a user is given the
opportunity to re-edit a failed history substitution.
- 'histverify'
+ ‘histverify’
If set, and Readline is being used, the results of history
substitution are not immediately passed to the shell parser.
Instead, the resulting line is loaded into the Readline
editing buffer, allowing further modification.
- 'hostcomplete'
+ ‘hostcomplete’
If set, and Readline is being used, Bash will attempt to
- perform hostname completion when a word containing a '@' is
+ perform hostname completion when a word containing a ‘@’ is
being completed (*note Commands For Completion::). This
option is enabled by default.
- 'huponexit'
- If set, Bash will send 'SIGHUP' to all jobs when an
+ ‘huponexit’
+ If set, Bash will send ‘SIGHUP’ to all jobs when an
interactive login shell exits (*note Signals::).
- 'inherit_errexit'
+ ‘inherit_errexit’
If set, command substitution inherits the value of the
- 'errexit' option, instead of unsetting it in the subshell
+ ‘errexit’ option, instead of unsetting it in the subshell
environment. This option is enabled when POSIX mode is
enabled.
- 'interactive_comments'
- Allow a word beginning with '#' to cause that word and all
+ ‘interactive_comments’
+ Allow a word beginning with ‘#’ to cause that word and all
remaining characters on that line to be ignored in an
interactive shell. This option is enabled by default.
- 'lastpipe'
+ ‘lastpipe’
If set, and job control is not active, the shell runs the last
command of a pipeline not executed in the background in the
current shell environment.
- 'lithist'
- If enabled, and the 'cmdhist' option is enabled, multi-line
+ ‘lithist’
+ If enabled, and the ‘cmdhist’ option is enabled, multi-line
commands are saved to the history with embedded newlines
rather than using semicolon separators where possible.
- 'localvar_inherit'
+ ‘localvar_inherit’
If set, local variables inherit the value and attributes of a
variable of the same name that exists at a previous scope
- before any new value is assigned. The 'nameref' attribute is
+ before any new value is assigned. The ‘nameref’ attribute is
not inherited.
- 'localvar_unset'
- If set, calling 'unset' on local variables in previous
+ ‘localvar_unset’
+ If set, calling ‘unset’ on local variables in previous
function scopes marks them so subsequent lookups find them
unset until that function returns. This is identical to the
behavior of unsetting local variables at the current function
scope.
- 'login_shell'
+ ‘login_shell’
The shell sets this option if it is started as a login shell
(*note Invoking Bash::). The value may not be changed.
- 'mailwarn'
+ ‘mailwarn’
If set, and a file that Bash is checking for mail has been
- accessed since the last time it was checked, the message '"The
- mail in MAILFILE has been read"' is displayed.
+ accessed since the last time it was checked, the message ‘"The
+ mail in MAILFILE has been read"’ is displayed.
- 'no_empty_cmd_completion'
+ ‘no_empty_cmd_completion’
If set, and Readline is being used, Bash will not attempt to
- search the 'PATH' for possible completions when completion is
+ search the ‘PATH’ for possible completions when completion is
attempted on an empty line.
- 'nocaseglob'
+ ‘nocaseglob’
If set, Bash matches filenames in a case-insensitive fashion
when performing filename expansion.
- 'nocasematch'
+ ‘nocasematch’
If set, Bash matches patterns in a case-insensitive fashion
- when performing matching while executing 'case' or '[['
+ when performing matching while executing ‘case’ or ‘[[’
conditional commands (*note Conditional Constructs::, when
performing pattern substitution word expansions, or when
filtering possible completions as part of programmable
completion.
- 'noexpand_translation'
+ ‘noexpand_translation’
If set, Bash encloses the translated results of $"..."
quoting in single quotes instead of double quotes. If the
string is not translated, this has no effect.
- 'nullglob'
+ ‘nullglob’
If set, filename expansion patterns which match no files
(*note Filename Expansion::) expand to nothing and are
removed, rather than expanding to themselves.
- 'patsub_replacement'
- If set, Bash expands occurrences of '&' in the replacement
+ ‘patsub_replacement’
+ If set, Bash expands occurrences of ‘&’ in the replacement
string of pattern substitution to the text matched by the
pattern, as described above (*note Shell Parameter
Expansion::). This option is enabled by default.
- 'progcomp'
+ ‘progcomp’
If set, the programmable completion facilities (*note
Programmable Completion::) are enabled. This option is
enabled by default.
- 'progcomp_alias'
+ ‘progcomp_alias’
If set, and programmable completion is enabled, Bash treats a
command name that doesn't have any completions as a possible
alias and attempts alias expansion. If it has an alias, Bash
attempts programmable completion using the command word
resulting from the expanded alias.
- 'promptvars'
+ ‘promptvars’
If set, prompt strings undergo parameter expansion, command
substitution, arithmetic expansion, and quote removal after
being expanded as described below (*note Controlling the
Prompt::). This option is enabled by default.
- 'restricted_shell'
+ ‘restricted_shell’
The shell sets this option if it is started in restricted mode
(*note The Restricted Shell::). The value may not be changed.
This is not reset when the startup files are executed,
allowing the startup files to discover whether or not a shell
is restricted.
- 'shift_verbose'
- If this is set, the 'shift' builtin prints an error message
+ ‘shift_verbose’
+ If this is set, the ‘shift’ builtin prints an error message
when the shift count exceeds the number of positional
parameters.
- 'sourcepath'
- If set, the '.' ('source') builtin uses the value of 'PATH' to
+ ‘sourcepath’
+ If set, the ‘.’ (‘source’) builtin uses the value of ‘PATH’ to
find the directory containing the file supplied as an
argument. This option is enabled by default.
- 'varredir_close'
+ ‘varredir_close’
If set, the shell automatically closes file descriptors
- assigned using the '{varname}' redirection syntax (*note
+ assigned using the ‘{varname}’ redirection syntax (*note
Redirections::) instead of leaving them open when the command
completes.
- 'xpg_echo'
- If set, the 'echo' builtin expands backslash-escape sequences
- by default. If the 'posix' shell option (*note The Set
- Builtin::) is also enabled, 'echo' does not interpret any
+ ‘xpg_echo’
+ If set, the ‘echo’ builtin expands backslash-escape sequences
+ by default. If the ‘posix’ shell option (*note The Set
+ Builtin::) is also enabled, ‘echo’ does not interpret any
options.
\1f
Bash uses certain shell variables in the same way as the Bourne shell.
In some cases, Bash assigns a default value to the variable.
-'CDPATH'
+‘CDPATH’
A colon-separated list of directories used as a search path for the
- 'cd' builtin command.
+ ‘cd’ builtin command.
-'HOME'
- The current user's home directory; the default for the 'cd' builtin
+‘HOME’
+ The current user's home directory; the default for the ‘cd’ builtin
command. The value of this variable is also used by tilde
expansion (*note Tilde Expansion::).
-'IFS'
+‘IFS’
A list of characters that separate fields; used when the shell
splits words as part of expansion.
-'MAIL'
+‘MAIL’
If this parameter is set to a filename or directory name and the
- 'MAILPATH' variable is not set, Bash informs the user of the
+ ‘MAILPATH’ variable is not set, Bash informs the user of the
arrival of mail in the specified file or Maildir-format directory.
-'MAILPATH'
+‘MAILPATH’
A colon-separated list of filenames which the shell periodically
checks for new mail. Each list entry can specify the message that
is printed when new mail arrives in the mail file by separating the
- filename from the message with a '?'. When used in the text of the
- message, '$_' expands to the name of the current mail file.
+ filename from the message with a ‘?’. When used in the text of the
+ message, ‘$_’ expands to the name of the current mail file.
-'OPTARG'
- The value of the last option argument processed by the 'getopts'
+‘OPTARG’
+ The value of the last option argument processed by the ‘getopts’
builtin.
-'OPTIND'
- The index of the last option argument processed by the 'getopts'
+‘OPTIND’
+ The index of the last option argument processed by the ‘getopts’
builtin.
-'PATH'
+‘PATH’
A colon-separated list of directories in which the shell looks for
commands. A zero-length (null) directory name in the value of
- 'PATH' indicates the current directory. A null directory name may
+ ‘PATH’ indicates the current directory. A null directory name may
appear as two adjacent colons, or as an initial or trailing colon.
-'PS1'
- The primary prompt string. The default value is '\s-\v\$ '. *Note
+‘PS1’
+ The primary prompt string. The default value is ‘\s-\v\$ ’. *Note
Controlling the Prompt::, for the complete list of escape sequences
- that are expanded before 'PS1' is displayed.
+ that are expanded before ‘PS1’ is displayed.
-'PS2'
- The secondary prompt string. The default value is '> '. 'PS2' is
- expanded in the same way as 'PS1' before being displayed.
+‘PS2’
+ The secondary prompt string. The default value is ‘> ’. ‘PS2’ is
+ expanded in the same way as ‘PS1’ before being displayed.
\1f
File: bash.info, Node: Bash Variables, Prev: Bourne Shell Variables, Up: Shell Variables
variables for controlling the job control facilities (*note Job Control
Variables::).
-'_'
+‘_’
($_, an underscore.) At shell startup, set to the pathname used to
invoke the shell or shell script being executed as passed in the
environment or argument list. Subsequently, expands to the last
command. When checking mail, this parameter holds the name of the
mail file.
-'BASH'
+‘BASH’
The full pathname used to execute the current instance of Bash.
-'BASHOPTS'
+‘BASHOPTS’
A colon-separated list of enabled shell options. Each word in the
- list is a valid argument for the '-s' option to the 'shopt' builtin
+ list is a valid argument for the ‘-s’ option to the ‘shopt’ builtin
command (*note The Shopt Builtin::). The options appearing in
- 'BASHOPTS' are those reported as 'on' by 'shopt'. If this variable
+ ‘BASHOPTS’ are those reported as ‘on’ by ‘shopt’. If this variable
is in the environment when Bash starts up, each shell option in the
list will be enabled before reading any startup files. This
variable is readonly.
-'BASHPID'
+‘BASHPID’
Expands to the process ID of the current Bash process. This
- differs from '$$' under certain circumstances, such as subshells
+ differs from ‘$$’ under certain circumstances, such as subshells
that do not require Bash to be re-initialized. Assignments to
- 'BASHPID' have no effect. If 'BASHPID' is unset, it loses its
+ ‘BASHPID’ have no effect. If ‘BASHPID’ is unset, it loses its
special properties, even if it is subsequently reset.
-'BASH_ALIASES'
+‘BASH_ALIASES’
An associative array variable whose members correspond to the
- internal list of aliases as maintained by the 'alias' builtin.
+ internal list of aliases as maintained by the ‘alias’ builtin.
(*note Bourne Shell Builtins::). Elements added to this array
appear in the alias list; however, unsetting array elements
currently does not cause aliases to be removed from the alias list.
- If 'BASH_ALIASES' is unset, it loses its special properties, even
+ If ‘BASH_ALIASES’ is unset, it loses its special properties, even
if it is subsequently reset.
-'BASH_ARGC'
+‘BASH_ARGC’
An array variable whose values are the number of parameters in each
frame of the current Bash execution call stack. The number of
parameters to the current subroutine (shell function or script
- executed with '.' or 'source') is at the top of the stack. When a
+ executed with ‘.’ or ‘source’) is at the top of the stack. When a
subroutine is executed, the number of parameters passed is pushed
- onto 'BASH_ARGC'. The shell sets 'BASH_ARGC' only when in extended
+ onto ‘BASH_ARGC’. The shell sets ‘BASH_ARGC’ only when in extended
debugging mode (see *note The Shopt Builtin:: for a description of
- the 'extdebug' option to the 'shopt' builtin). Setting 'extdebug'
+ the ‘extdebug’ option to the ‘shopt’ builtin). Setting ‘extdebug’
after the shell has started to execute a script, or referencing
- this variable when 'extdebug' is not set, may result in
- inconsistent values. Assignments to 'BASH_ARGC' have no effect,
+ this variable when ‘extdebug’ is not set, may result in
+ inconsistent values. Assignments to ‘BASH_ARGC’ have no effect,
and it may not be unset.
-'BASH_ARGV'
+‘BASH_ARGV’
An array variable containing all of the parameters in the current
Bash execution call stack. The final parameter of the last
subroutine call is at the top of the stack; the first parameter of
the initial call is at the bottom. When a subroutine is executed,
- the parameters supplied are pushed onto 'BASH_ARGV'. The shell
- sets 'BASH_ARGV' only when in extended debugging mode (see *note
- The Shopt Builtin:: for a description of the 'extdebug' option to
- the 'shopt' builtin). Setting 'extdebug' after the shell has
+ the parameters supplied are pushed onto ‘BASH_ARGV’. The shell
+ sets ‘BASH_ARGV’ only when in extended debugging mode (see *note
+ The Shopt Builtin:: for a description of the ‘extdebug’ option to
+ the ‘shopt’ builtin). Setting ‘extdebug’ after the shell has
started to execute a script, or referencing this variable when
- 'extdebug' is not set, may result in inconsistent values.
- Assignments to 'BASH_ARGV' have no effect, and it may not be unset.
+ ‘extdebug’ is not set, may result in inconsistent values.
+ Assignments to ‘BASH_ARGV’ have no effect, and it may not be unset.
-'BASH_ARGV0'
+‘BASH_ARGV0’
When referenced, this variable expands to the name of the shell or
- shell script (identical to '$0'; *Note Special Parameters::, for
+ shell script (identical to ‘$0’; *Note Special Parameters::, for
the description of special parameter 0). Assignment to
- 'BASH_ARGV0' causes the value assigned to also be assigned to '$0'.
- If 'BASH_ARGV0' is unset, it loses its special properties, even if
+ ‘BASH_ARGV0’ causes the value assigned to also be assigned to ‘$0’.
+ If ‘BASH_ARGV0’ is unset, it loses its special properties, even if
it is subsequently reset.
-'BASH_CMDS'
+‘BASH_CMDS’
An associative array variable whose members correspond to the
- internal hash table of commands as maintained by the 'hash' builtin
+ internal hash table of commands as maintained by the ‘hash’ builtin
(*note Bourne Shell Builtins::). Elements added to this array
appear in the hash table; however, unsetting array elements
currently does not cause command names to be removed from the hash
- table. If 'BASH_CMDS' is unset, it loses its special properties,
+ table. If ‘BASH_CMDS’ is unset, it loses its special properties,
even if it is subsequently reset.
-'BASH_COMMAND'
+‘BASH_COMMAND’
The command currently being executed or about to be executed,
unless the shell is executing a command as the result of a trap, in
which case it is the command executing at the time of the trap. If
- 'BASH_COMMAND' is unset, it loses its special properties, even if
+ ‘BASH_COMMAND’ is unset, it loses its special properties, even if
it is subsequently reset.
-'BASH_COMPAT'
+‘BASH_COMPAT’
The value is used to set the shell's compatibility level. *Note
Shell Compatibility Mode::, for a description of the various
compatibility levels and their effects. The value may be a decimal
number (e.g., 4.2) or an integer (e.g., 42) corresponding to the
- desired compatibility level. If 'BASH_COMPAT' is unset or set to
+ desired compatibility level. If ‘BASH_COMPAT’ is unset or set to
the empty string, the compatibility level is set to the default for
- the current version. If 'BASH_COMPAT' is set to a value that is
+ the current version. If ‘BASH_COMPAT’ is set to a value that is
not one of the valid compatibility levels, the shell prints an
error message and sets the compatibility level to the default for
- the current version. The valid values correspond to the
- compatibility levels described below (*note Shell Compatibility
+ the current version. A subset of the valid values correspond to
+ the compatibility levels described below (*note Shell Compatibility
Mode::). For example, 4.2 and 42 are valid values that correspond
- to the 'compat42' 'shopt' option and set the compatibility level to
+ to the ‘compat42’ ‘shopt’ option and set the compatibility level to
42. The current version is also a valid value.
-'BASH_ENV'
+‘BASH_ENV’
If this variable is set when Bash is invoked to execute a shell
script, its value is expanded and used as the name of a startup
file to read before executing the script. *Note Bash Startup
Files::.
-'BASH_EXECUTION_STRING'
- The command argument to the '-c' invocation option.
+‘BASH_EXECUTION_STRING’
+ The command argument to the ‘-c’ invocation option.
-'BASH_LINENO'
+‘BASH_LINENO’
An array variable whose members are the line numbers in source
- files where each corresponding member of 'FUNCNAME' was invoked.
- '${BASH_LINENO[$i]}' is the line number in the source file
- ('${BASH_SOURCE[$i+1]}') where '${FUNCNAME[$i]}' was called (or
- '${BASH_LINENO[$i-1]}' if referenced within another shell
- function). Use 'LINENO' to obtain the current line number.
- Assignments to 'BASH_LINENO' have no effect, and it may not be
+ files where each corresponding member of ‘FUNCNAME’ was invoked.
+ ‘${BASH_LINENO[$i]}’ is the line number in the source file
+ (‘${BASH_SOURCE[$i+1]}’) where ‘${FUNCNAME[$i]}’ was called (or
+ ‘${BASH_LINENO[$i-1]}’ if referenced within another shell
+ function). Use ‘LINENO’ to obtain the current line number.
+ Assignments to ‘BASH_LINENO’ have no effect, and it may not be
unset.
-'BASH_LOADABLES_PATH'
+‘BASH_LOADABLES_PATH’
A colon-separated list of directories in which the shell looks for
- dynamically loadable builtins specified by the 'enable' command.
+ dynamically loadable builtins specified by the ‘enable’ command.
-'BASH_MONOSECONDS'
+‘BASH_MONOSECONDS’
Each time this variable is referenced, it expands to the value
returned by the system's monotonic clock, if one is available. If
- there is no monotonic clock, this is equivalent to 'EPOCHSECONDS'.
- If 'BASH_MONOSECONDS' is unset, it loses its special properties,
+ there is no monotonic clock, this is equivalent to ‘EPOCHSECONDS’.
+ If ‘BASH_MONOSECONDS’ is unset, it loses its special properties,
even if it is subsequently reset.
-'BASH_REMATCH'
- An array variable whose members are assigned by the '=~' binary
- operator to the '[[' conditional command (*note Conditional
+‘BASH_REMATCH’
+ An array variable whose members are assigned by the ‘=~’ binary
+ operator to the ‘[[’ conditional command (*note Conditional
Constructs::). The element with index 0 is the portion of the
string matching the entire regular expression. The element with
index N is the portion of the string matching the Nth parenthesized
subexpression.
-'BASH_SOURCE'
+‘BASH_SOURCE’
An array variable whose members are the source filenames where the
- corresponding shell function names in the 'FUNCNAME' array variable
- are defined. The shell function '${FUNCNAME[$i]}' is defined in
- the file '${BASH_SOURCE[$i]}' and called from
- '${BASH_SOURCE[$i+1]}' Assignments to 'BASH_SOURCE' have no effect,
+ corresponding shell function names in the ‘FUNCNAME’ array variable
+ are defined. The shell function ‘${FUNCNAME[$i]}’ is defined in
+ the file ‘${BASH_SOURCE[$i]}’ and called from
+ ‘${BASH_SOURCE[$i+1]}’ Assignments to ‘BASH_SOURCE’ have no effect,
and it may not be unset.
-'BASH_SUBSHELL'
+‘BASH_SUBSHELL’
Incremented by one within each subshell or subshell environment
when the shell begins executing in that environment. The initial
- value is 0. If 'BASH_SUBSHELL' is unset, it loses its special
+ value is 0. If ‘BASH_SUBSHELL’ is unset, it loses its special
properties, even if it is subsequently reset.
-'BASH_TRAPSIG'
+‘BASH_TRAPSIG’
Set to the signal number corresponding to the trap action being
- executed during its execution. See the description of 'trap'
+ executed during its execution. See the description of ‘trap’
(*note Bourne Shell Builtins::) for information about signal
numbers and trap execution.
-'BASH_VERSINFO'
+‘BASH_VERSINFO’
A readonly array variable (*note Arrays::) whose members hold
version information for this instance of Bash. The values assigned
to the array members are as follows:
- 'BASH_VERSINFO[0]'
- The major version number (the "release").
+ ‘BASH_VERSINFO[0]’
+ The major version number (the “release”).
- 'BASH_VERSINFO[1]'
- The minor version number (the "version").
+ ‘BASH_VERSINFO[1]’
+ The minor version number (the “version”).
- 'BASH_VERSINFO[2]'
+ ‘BASH_VERSINFO[2]’
The patch level.
- 'BASH_VERSINFO[3]'
+ ‘BASH_VERSINFO[3]’
The build version.
- 'BASH_VERSINFO[4]'
- The release status (e.g., 'beta1').
+ ‘BASH_VERSINFO[4]’
+ The release status (e.g., ‘beta’).
- 'BASH_VERSINFO[5]'
- The value of 'MACHTYPE'.
+ ‘BASH_VERSINFO[5]’
+ The value of ‘MACHTYPE’.
-'BASH_VERSION'
+‘BASH_VERSION’
The version number of the current instance of Bash.
-'BASH_XTRACEFD'
+‘BASH_XTRACEFD’
If set to an integer corresponding to a valid file descriptor, Bash
- will write the trace output generated when 'set -x' is enabled to
+ will write the trace output generated when ‘set -x’ is enabled to
that file descriptor. This allows tracing output to be separated
from diagnostic and error messages. The file descriptor is closed
- when 'BASH_XTRACEFD' is unset or assigned a new value. Unsetting
- 'BASH_XTRACEFD' or assigning it the empty string causes the trace
+ when ‘BASH_XTRACEFD’ is unset or assigned a new value. Unsetting
+ ‘BASH_XTRACEFD’ or assigning it the empty string causes the trace
output to be sent to the standard error. Note that setting
- 'BASH_XTRACEFD' to 2 (the standard error file descriptor) and then
+ ‘BASH_XTRACEFD’ to 2 (the standard error file descriptor) and then
unsetting it will result in the standard error being closed.
-'CHILD_MAX'
+‘CHILD_MAX’
Set the number of exited child status values for the shell to
remember. Bash will not allow this value to be decreased below a
POSIX-mandated minimum, and there is a maximum value (currently
8192) that this may not exceed. The minimum value is
system-dependent.
-'COLUMNS'
- Used by the 'select' command to determine the terminal width when
- printing selection lists. Automatically set if the 'checkwinsize'
+‘COLUMNS’
+ Used by the ‘select’ command to determine the terminal width when
+ printing selection lists. Automatically set if the ‘checkwinsize’
option is enabled (*note The Shopt Builtin::), or in an interactive
- shell upon receipt of a 'SIGWINCH'.
+ shell upon receipt of a ‘SIGWINCH’.
-'COMP_CWORD'
- An index into '${COMP_WORDS}' of the word containing the current
+‘COMP_CWORD’
+ An index into ‘${COMP_WORDS}’ of the word containing the current
cursor position. This variable is available only in shell
functions invoked by the programmable completion facilities (*note
Programmable Completion::).
-'COMP_LINE'
+‘COMP_LINE’
The current command line. This variable is available only in shell
functions and external commands invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMP_POINT'
+‘COMP_POINT’
The index of the current cursor position relative to the beginning
of the current command. If the current cursor position is at the
end of the current command, the value of this variable is equal to
- '${#COMP_LINE}'. This variable is available only in shell
+ ‘${#COMP_LINE}’. This variable is available only in shell
functions and external commands invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMP_TYPE'
+‘COMP_TYPE’
Set to an integer value corresponding to the type of completion
attempted that caused a completion function to be called: <TAB>,
- for normal completion, '?', for listing completions after
- successive tabs, '!', for listing alternatives on partial word
- completion, '@', to list completions if the word is not unmodified,
- or '%', for menu completion. This variable is available only in
+ for normal completion, ‘?’, for listing completions after
+ successive tabs, ‘!’, for listing alternatives on partial word
+ completion, ‘@’, to list completions if the word is not unmodified,
+ or ‘%’, for menu completion. This variable is available only in
shell functions and external commands invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMP_KEY'
+‘COMP_KEY’
The key (or final key of a key sequence) used to invoke the current
completion function.
-'COMP_WORDBREAKS'
+‘COMP_WORDBREAKS’
The set of characters that the Readline library treats as word
- separators when performing word completion. If 'COMP_WORDBREAKS'
+ separators when performing word completion. If ‘COMP_WORDBREAKS’
is unset, it loses its special properties, even if it is
subsequently reset.
-'COMP_WORDS'
+‘COMP_WORDS’
An array variable consisting of the individual words in the current
command line. The line is split into words as Readline would split
- it, using 'COMP_WORDBREAKS' as described above. This variable is
+ it, using ‘COMP_WORDBREAKS’ as described above. This variable is
available only in shell functions invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMPREPLY'
+‘COMPREPLY’
An array variable from which Bash reads the possible completions
generated by a shell function invoked by the programmable
completion facility (*note Programmable Completion::). Each array
element contains one possible completion.
-'COPROC'
+‘COPROC’
An array variable created to hold the file descriptors for output
from and input to an unnamed coprocess (*note Coprocesses::).
-'DIRSTACK'
+‘DIRSTACK’
An array variable containing the current contents of the directory
stack. Directories appear in the stack in the order they are
- displayed by the 'dirs' builtin. Assigning to members of this
+ displayed by the ‘dirs’ builtin. Assigning to members of this
array variable may be used to modify directories already in the
- stack, but the 'pushd' and 'popd' builtins must be used to add and
+ stack, but the ‘pushd’ and ‘popd’ builtins must be used to add and
remove directories. Assignment to this variable will not change
- the current directory. If 'DIRSTACK' is unset, it loses its
+ the current directory. If ‘DIRSTACK’ is unset, it loses its
special properties, even if it is subsequently reset.
-'EMACS'
+‘EMACS’
If Bash finds this variable in the environment when the shell
- starts with value 't', it assumes that the shell is running in an
+ starts with value ‘t’, it assumes that the shell is running in an
Emacs shell buffer and disables line editing.
-'ENV'
- Expanded and executed similarly to 'BASH_ENV' (*note Bash Startup
+‘ENV’
+ Expanded and executed similarly to ‘BASH_ENV’ (*note Bash Startup
Files::) when an interactive shell is invoked in POSIX Mode (*note
Bash POSIX Mode::).
-'EPOCHREALTIME'
+‘EPOCHREALTIME’
Each time this parameter is referenced, it expands to the number of
seconds since the Unix Epoch as a floating point value with
micro-second granularity (see the documentation for the C library
- function 'time' for the definition of Epoch). Assignments to
- 'EPOCHREALTIME' are ignored. If 'EPOCHREALTIME' is unset, it loses
+ function ‘time’ for the definition of Epoch). Assignments to
+ ‘EPOCHREALTIME’ are ignored. If ‘EPOCHREALTIME’ is unset, it loses
its special properties, even if it is subsequently reset.
-'EPOCHSECONDS'
+‘EPOCHSECONDS’
Each time this parameter is referenced, it expands to the number of
seconds since the Unix Epoch (see the documentation for the C
- library function 'time' for the definition of Epoch). Assignments
- to 'EPOCHSECONDS' are ignored. If 'EPOCHSECONDS' is unset, it
+ library function ‘time’ for the definition of Epoch). Assignments
+ to ‘EPOCHSECONDS’ are ignored. If ‘EPOCHSECONDS’ is unset, it
loses its special properties, even if it is subsequently reset.
-'EUID'
+‘EUID’
The numeric effective user id of the current user. This variable
is readonly.
-'EXECIGNORE'
+‘EXECIGNORE’
A colon-separated list of shell patterns (*note Pattern Matching::)
defining the list of filenames to be ignored by command search
- using 'PATH'. Files whose full pathnames match one of these
+ using ‘PATH’. Files whose full pathnames match one of these
patterns are not considered executable files for the purposes of
- completion and command execution via 'PATH' lookup. This does not
- affect the behavior of the '[', 'test', and '[[' commands. Full
+ completion and command execution via ‘PATH’ lookup. This does not
+ affect the behavior of the ‘[’, ‘test’, and ‘[[’ commands. Full
pathnames in the command hash table are not subject to
- 'EXECIGNORE'. Use this variable to ignore shared library files
+ ‘EXECIGNORE’. Use this variable to ignore shared library files
that have the executable bit set, but are not executable files.
- The pattern matching honors the setting of the 'extglob' shell
+ The pattern matching honors the setting of the ‘extglob’ shell
option.
-'FCEDIT'
- The editor used as a default by the '-e' option to the 'fc' builtin
+‘FCEDIT’
+ The editor used as a default by the ‘-e’ option to the ‘fc’ builtin
command.
-'FIGNORE'
+‘FIGNORE’
A colon-separated list of suffixes to ignore when performing
filename completion. A filename whose suffix matches one of the
- entries in 'FIGNORE' is excluded from the list of matched
- filenames. A sample value is '.o:~'
+ entries in ‘FIGNORE’ is excluded from the list of matched
+ filenames. A sample value is ‘.o:~’
-'FUNCNAME'
+‘FUNCNAME’
An array variable containing the names of all shell functions
currently in the execution call stack. The element with index 0 is
the name of any currently-executing shell function. The
- bottom-most element (the one with the highest index) is '"main"'.
+ bottom-most element (the one with the highest index) is ‘"main"’.
This variable exists only when a shell function is executing.
- Assignments to 'FUNCNAME' have no effect. If 'FUNCNAME' is unset,
+ Assignments to ‘FUNCNAME’ have no effect. If ‘FUNCNAME’ is unset,
it loses its special properties, even if it is subsequently reset.
- This variable can be used with 'BASH_LINENO' and 'BASH_SOURCE'.
- Each element of 'FUNCNAME' has corresponding elements in
- 'BASH_LINENO' and 'BASH_SOURCE' to describe the call stack. For
- instance, '${FUNCNAME[$i]}' was called from the file
- '${BASH_SOURCE[$i+1]}' at line number '${BASH_LINENO[$i]}'. The
- 'caller' builtin displays the current call stack using this
+ This variable can be used with ‘BASH_LINENO’ and ‘BASH_SOURCE’.
+ Each element of ‘FUNCNAME’ has corresponding elements in
+ ‘BASH_LINENO’ and ‘BASH_SOURCE’ to describe the call stack. For
+ instance, ‘${FUNCNAME[$i]}’ was called from the file
+ ‘${BASH_SOURCE[$i+1]}’ at line number ‘${BASH_LINENO[$i]}’. The
+ ‘caller’ builtin displays the current call stack using this
information.
-'FUNCNEST'
+‘FUNCNEST’
If set to a numeric value greater than 0, defines a maximum
function nesting level. Function invocations that exceed this
nesting level will cause the current command to abort.
-'GLOBIGNORE'
+‘GLOBIGNORE’
A colon-separated list of patterns defining the set of file names
to be ignored by filename expansion. If a file name matched by a
filename expansion pattern also matches one of the patterns in
- 'GLOBIGNORE', it is removed from the list of matches. The pattern
- matching honors the setting of the 'extglob' shell option.
+ ‘GLOBIGNORE’, it is removed from the list of matches. The pattern
+ matching honors the setting of the ‘extglob’ shell option.
-'GLOBSORT'
+‘GLOBSORT’
Control how the results of filename expansion are sorted. The
value of this variable specifies the sort criteria and sort order
for the results of filename expansion. If this variable is unset
or set to the null string, filename expansion uses the historical
behavior of sorting by name. If set, a valid value begins with an
- optional '+', which is ignored, or '-', which reverses the sort
+ optional ‘+’, which is ignored, or ‘-’, which reverses the sort
order from ascending to descending, followed by a sort specifier.
- The valid sort specifiers are 'name', 'size', 'mtime', 'atime',
- 'ctime', and 'blocks', which sort the files on name, file size,
+ The valid sort specifiers are ‘name’, ‘size’, ‘mtime’, ‘atime’,
+ ‘ctime’, and ‘blocks’, which sort the files on name, file size,
modification time, access time, inode change time, and number of
blocks, respectively.
- For example, a value of '-mtime' sorts the results in descending
+ For example, a value of ‘-mtime’ sorts the results in descending
order by modification time (newest first).
- A sort specifier of 'nosort' disables sorting completely; the
+ A sort specifier of ‘nosort’ disables sorting completely; the
results are returned in the order they are read from the file
system,.
If the sort specifier is missing, it defaults to NAME, so a value
- of '+' is equivalent to the null string, and a value of '-' sorts
+ of ‘+’ is equivalent to the null string, and a value of ‘-’ sorts
by name in descending order.
Any invalid value restores the historical sorting behavior.
-'GROUPS'
+‘GROUPS’
An array variable containing the list of groups of which the
- current user is a member. Assignments to 'GROUPS' have no effect.
- If 'GROUPS' is unset, it loses its special properties, even if it
+ current user is a member. Assignments to ‘GROUPS’ have no effect.
+ If ‘GROUPS’ is unset, it loses its special properties, even if it
is subsequently reset.
-'histchars'
+‘histchars’
Up to three characters which control history expansion, quick
substitution, and tokenization (*note History Interaction::). The
- first character is the "history expansion" character, that is, the
+ first character is the “history expansion” character, that is, the
character which signifies the start of a history expansion,
- normally '!'. The second character is the character which
+ normally ‘!’. The second character is the character which
signifies "quick substitution" when seen as the first character on
- a line, normally '^'. The optional third character is the
+ a line, normally ‘^’. The optional third character is the
character which indicates that the remainder of the line is a
- comment when found as the first character of a word, usually '#'.
+ comment when found as the first character of a word, usually ‘#’.
The history comment character causes history substitution to be
skipped for the remaining words on the line. It does not
necessarily cause the shell parser to treat the rest of the line as
a comment.
-'HISTCMD'
+‘HISTCMD’
The history number, or index in the history list, of the current
- command. Assignments to 'HISTCMD' are ignored. If 'HISTCMD' is
+ command. Assignments to ‘HISTCMD’ are ignored. If ‘HISTCMD’ is
unset, it loses its special properties, even if it is subsequently
reset.
-'HISTCONTROL'
+‘HISTCONTROL’
A colon-separated list of values controlling how commands are saved
- on the history list. If the list of values includes 'ignorespace',
+ on the history list. If the list of values includes ‘ignorespace’,
lines which begin with a space character are not saved in the
- history list. A value of 'ignoredups' causes lines which match the
- previous history entry to not be saved. A value of 'ignoreboth' is
- shorthand for 'ignorespace' and 'ignoredups'. A value of
- 'erasedups' causes all previous lines matching the current line to
+ history list. A value of ‘ignoredups’ causes lines which match the
+ previous history entry to not be saved. A value of ‘ignoreboth’ is
+ shorthand for ‘ignorespace’ and ‘ignoredups’. A value of
+ ‘erasedups’ causes all previous lines matching the current line to
be removed from the history list before that line is saved. Any
- value not in the above list is ignored. If 'HISTCONTROL' is unset,
+ value not in the above list is ignored. If ‘HISTCONTROL’ is unset,
or does not include a valid value, all lines read by the shell
parser are saved on the history list, subject to the value of
- 'HISTIGNORE'. The second and subsequent lines of a multi-line
+ ‘HISTIGNORE’. The second and subsequent lines of a multi-line
compound command are not tested, and are added to the history
- regardless of the value of 'HISTCONTROL'.
+ regardless of the value of ‘HISTCONTROL’.
-'HISTFILE'
+‘HISTFILE’
The name of the file to which the command history is saved. Bash
- assigns a default value of '~/.bash_history'. If 'HISTFILE' is
+ assigns a default value of ‘~/.bash_history’. If ‘HISTFILE’ is
unset or null, the command history is not saved when a shell exits.
-'HISTFILESIZE'
+‘HISTFILESIZE’
The maximum number of lines contained in the history file. When
this variable is assigned a value, the history file is truncated,
if necessary, to contain no more than that number of lines by
this size after writing it when a shell exits. If the value is 0,
the history file is truncated to zero size. Non-numeric values and
numeric values less than zero inhibit truncation. The shell sets
- the default value to the value of 'HISTSIZE' after reading any
+ the default value to the value of ‘HISTSIZE’ after reading any
startup files.
-'HISTIGNORE'
+‘HISTIGNORE’
A colon-separated list of patterns used to decide which command
lines should be saved on the history list. Each pattern is
anchored at the beginning of the line and must match the complete
- line (no implicit '*' is appended). Each pattern is tested against
- the line after the checks specified by 'HISTCONTROL' are applied.
- In addition to the normal shell pattern matching characters, '&'
- matches the previous history line. '&' may be escaped using a
- backslash; the backslash is removed before attempting a match. The
- second and subsequent lines of a multi-line compound command are
- not tested, and are added to the history regardless of the value of
- 'HISTIGNORE'. The pattern matching honors the setting of the
- 'extglob' shell option.
-
- 'HISTIGNORE' subsumes the function of 'HISTCONTROL'. A pattern of
- '&' is identical to 'ignoredups', and a pattern of '[ ]*' is
- identical to 'ignorespace'. Combining these two patterns,
+ line (Bash will not implicitly append a ‘*’). Each pattern is
+ tested against the line after the checks specified by ‘HISTCONTROL’
+ are applied. In addition to the normal shell pattern matching
+ characters, ‘&’ matches the previous history line. ‘&’ may be
+ escaped using a backslash; the backslash is removed before
+ attempting a match. The second and subsequent lines of a
+ multi-line compound command are not tested, and are added to the
+ history regardless of the value of ‘HISTIGNORE’. The pattern
+ matching honors the setting of the ‘extglob’ shell option.
+
+ ‘HISTIGNORE’ subsumes the function of ‘HISTCONTROL’. A pattern of
+ ‘&’ is identical to ‘ignoredups’, and a pattern of ‘[ ]*’ is
+ identical to ‘ignorespace’. Combining these two patterns,
separating them with a colon, provides the functionality of
- 'ignoreboth'.
+ ‘ignoreboth’.
-'HISTSIZE'
+‘HISTSIZE’
The maximum number of commands to remember on the history list. If
the value is 0, commands are not saved in the history list.
Numeric values less than zero result in every command being saved
on the history list (there is no limit). The shell sets the
default value to 500 after reading any startup files.
-'HISTTIMEFORMAT'
+‘HISTTIMEFORMAT’
If this variable is set and not null, its value is used as a format
- string for 'strftime' to print the time stamp associated with each
- history entry displayed by the 'history' builtin. If this variable
- is set, time stamps are written to the history file so they may be
- preserved across shell sessions. This uses the history comment
- character to distinguish timestamps from other history lines.
-
-'HOSTFILE'
- Contains the name of a file in the same format as '/etc/hosts' that
+ string for ‘strftime’(3) to print the time stamp associated with
+ each history entry displayed by the ‘history’ builtin. If this
+ variable is set, time stamps are written to the history file so
+ they may be preserved across shell sessions. This uses the history
+ comment character to distinguish timestamps from other history
+ lines.
+
+‘HOSTFILE’
+ Contains the name of a file in the same format as ‘/etc/hosts’ that
should be read when the shell needs to complete a hostname. The
list of possible hostname completions may be changed while the
shell is running; the next time hostname completion is attempted
after the value is changed, Bash adds the contents of the new file
- to the existing list. If 'HOSTFILE' is set, but has no value, or
- does not name a readable file, Bash attempts to read '/etc/hosts'
+ to the existing list. If ‘HOSTFILE’ is set, but has no value, or
+ does not name a readable file, Bash attempts to read ‘/etc/hosts’
to obtain the list of possible hostname completions. When
- 'HOSTFILE' is unset, the hostname list is cleared.
+ ‘HOSTFILE’ is unset, the hostname list is cleared.
-'HOSTNAME'
+‘HOSTNAME’
The name of the current host.
-'HOSTTYPE'
+‘HOSTTYPE’
A string describing the machine Bash is running on.
-'IGNOREEOF'
- Controls the action of the shell on receipt of an 'EOF' character
+‘IGNOREEOF’
+ Controls the action of the shell on receipt of an ‘EOF’ character
as the sole input. If set, the value denotes the number of
- consecutive 'EOF' characters that can be read as the first
+ consecutive ‘EOF’ characters that can be read as the first
character on an input line before the shell will exit. If the
variable exists but does not have a numeric value, or has no value,
- then the default is 10. If the variable does not exist, then 'EOF'
+ then the default is 10. If the variable does not exist, then ‘EOF’
signifies the end of input to the shell. This is only in effect
for interactive shells.
-'INPUTRC'
+‘INPUTRC’
The name of the Readline initialization file, overriding the
- default of '~/.inputrc'.
+ default of ‘~/.inputrc’.
-'INSIDE_EMACS'
+‘INSIDE_EMACS’
If Bash finds this variable in the environment when the shell
starts, it assumes that the shell is running in an Emacs shell
buffer and may disable line editing depending on the value of
- 'TERM'.
+ ‘TERM’.
-'LANG'
+‘LANG’
Used to determine the locale category for any category not
- specifically selected with a variable starting with 'LC_'.
+ specifically selected with a variable starting with ‘LC_’.
-'LC_ALL'
- This variable overrides the value of 'LANG' and any other 'LC_'
+‘LC_ALL’
+ This variable overrides the value of ‘LANG’ and any other ‘LC_’
variable specifying a locale category.
-'LC_COLLATE'
+‘LC_COLLATE’
This variable determines the collation order used when sorting the
results of filename expansion, and determines the behavior of range
expressions, equivalence classes, and collating sequences within
filename expansion and pattern matching (*note Filename
Expansion::).
-'LC_CTYPE'
+‘LC_CTYPE’
This variable determines the interpretation of characters and the
behavior of character classes within filename expansion and pattern
matching (*note Filename Expansion::).
-'LC_MESSAGES'
+‘LC_MESSAGES’
This variable determines the locale used to translate double-quoted
- strings preceded by a '$' (*note Locale Translation::).
+ strings preceded by a ‘$’ (*note Locale Translation::).
-'LC_NUMERIC'
+‘LC_NUMERIC’
This variable determines the locale category used for number
formatting.
-'LC_TIME'
+‘LC_TIME’
This variable determines the locale category used for data and time
formatting.
-'LINENO'
+‘LINENO’
The line number in the script or shell function currently
- executing. If 'LINENO' is unset, it loses its special properties,
+ executing. If ‘LINENO’ is unset, it loses its special properties,
even if it is subsequently reset.
-'LINES'
- Used by the 'select' command to determine the column length for
- printing selection lists. Automatically set if the 'checkwinsize'
+‘LINES’
+ Used by the ‘select’ command to determine the column length for
+ printing selection lists. Automatically set if the ‘checkwinsize’
option is enabled (*note The Shopt Builtin::), or in an interactive
- shell upon receipt of a 'SIGWINCH'.
+ shell upon receipt of a ‘SIGWINCH’.
-'MACHTYPE'
+‘MACHTYPE’
A string that fully describes the system type on which Bash is
executing, in the standard GNU CPU-COMPANY-SYSTEM format.
-'MAILCHECK'
+‘MAILCHECK’
How often (in seconds) that the shell should check for mail in the
- files specified in the 'MAILPATH' or 'MAIL' variables. The default
+ files specified in the ‘MAILPATH’ or ‘MAIL’ variables. The default
is 60 seconds. When it is time to check for mail, the shell does
so before displaying the primary prompt. If this variable is
unset, or set to a value that is not a number greater than or equal
to zero, the shell disables mail checking.
-'MAPFILE'
- An array variable created to hold the text read by the 'mapfile'
+‘MAPFILE’
+ An array variable created to hold the text read by the ‘mapfile’
builtin when no variable name is supplied.
-'OLDPWD'
- The previous working directory as set by the 'cd' builtin.
+‘OLDPWD’
+ The previous working directory as set by the ‘cd’ builtin.
-'OPTERR'
+‘OPTERR’
If set to the value 1, Bash displays error messages generated by
- the 'getopts' builtin command.
+ the ‘getopts’ builtin command.
-'OSTYPE'
+‘OSTYPE’
A string describing the operating system Bash is running on.
-'PIPESTATUS'
+‘PIPESTATUS’
An array variable (*note Arrays::) containing a list of exit status
values from the processes in the most-recently-executed foreground
pipeline (which may contain only a single command).
-'POSIXLY_CORRECT'
+‘POSIXLY_CORRECT’
If this variable is in the environment when Bash starts, the shell
enters POSIX mode (*note Bash POSIX Mode::) before reading the
- startup files, as if the '--posix' invocation option had been
+ startup files, as if the ‘--posix’ invocation option had been
supplied. If it is set while the shell is running, Bash enables
POSIX mode, as if the command
set -o posix
had been executed. When the shell enters POSIX mode, it sets this
variable if it was not already set.
-'PPID'
+‘PPID’
The process ID of the shell's parent process. This variable is
readonly.
-'PROMPT_COMMAND'
+‘PROMPT_COMMAND’
If this variable is set, and is an array, the value of each set
element is interpreted as a command to execute before printing the
- primary prompt ('$PS1'). If this is set but not an array variable,
+ primary prompt (‘$PS1’). If this is set but not an array variable,
its value is used as a command to execute instead.
-'PROMPT_DIRTRIM'
+‘PROMPT_DIRTRIM’
If set to a number greater than zero, the value is used as the
number of trailing directory components to retain when expanding
- the '\w' and '\W' prompt string escapes (*note Controlling the
+ the ‘\w’ and ‘\W’ prompt string escapes (*note Controlling the
Prompt::). Characters removed are replaced with an ellipsis.
-'PS0'
- The value of this parameter is expanded like 'PS1' and displayed by
+‘PS0’
+ The value of this parameter is expanded like ‘PS1’ and displayed by
interactive shells after reading a command and before the command
is executed.
-'PS3'
- The value of this variable is used as the prompt for the 'select'
- command. If this variable is not set, the 'select' command prompts
- with '#? '
+‘PS3’
+ The value of this variable is used as the prompt for the ‘select’
+ command. If this variable is not set, the ‘select’ command prompts
+ with ‘#? ’
-'PS4'
- The value of this parameter is expanded like 'PS1' and the expanded
+‘PS4’
+ The value of this parameter is expanded like ‘PS1’ and the expanded
value is the prompt printed before the command line is echoed when
- the '-x' option is set (*note The Set Builtin::). The first
+ the ‘-x’ option is set (*note The Set Builtin::). The first
character of the expanded value is replicated multiple times, as
necessary, to indicate multiple levels of indirection. The default
- is '+ '.
+ is ‘+ ’.
-'PWD'
- The current working directory as set by the 'cd' builtin.
+‘PWD’
+ The current working directory as set by the ‘cd’ builtin.
-'RANDOM'
+‘RANDOM’
Each time this parameter is referenced, it expands to a random
integer between 0 and 32767. Assigning a value to this variable
- seeds the random number generator. If 'RANDOM' is unset, it loses
+ seeds the random number generator. If ‘RANDOM’ is unset, it loses
its special properties, even if it is subsequently reset.
-'READLINE_ARGUMENT'
+‘READLINE_ARGUMENT’
Any numeric argument given to a Readline command that was defined
- using 'bind -x' (*note Bash Builtins:: when it was invoked.
+ using ‘bind -x’ (*note Bash Builtins:: when it was invoked.
-'READLINE_LINE'
- The contents of the Readline line buffer, for use with 'bind -x'
+‘READLINE_LINE’
+ The contents of the Readline line buffer, for use with ‘bind -x’
(*note Bash Builtins::).
-'READLINE_MARK'
- The position of the "mark" (saved insertion point) in the Readline
- line buffer, for use with 'bind -x' (*note Bash Builtins::). The
+‘READLINE_MARK’
+ The position of the “mark” (saved insertion point) in the Readline
+ line buffer, for use with ‘bind -x’ (*note Bash Builtins::). The
characters between the insertion point and the mark are often
- called the "region".
+ called the “region”.
-'READLINE_POINT'
+‘READLINE_POINT’
The position of the insertion point in the Readline line buffer,
- for use with 'bind -x' (*note Bash Builtins::).
+ for use with ‘bind -x’ (*note Bash Builtins::).
-'REPLY'
- The default variable for the 'read' builtin.
+‘REPLY’
+ The default variable for the ‘read’ builtin.
-'SECONDS'
+‘SECONDS’
This variable expands to the number of seconds since the shell was
started. Assignment to this variable resets the count to the value
assigned, and the expanded value becomes the value assigned plus
the number of seconds since the assignment. The number of seconds
at shell invocation and the current time are always determined by
- querying the system clock. If 'SECONDS' is unset, it loses its
+ querying the system clock. If ‘SECONDS’ is unset, it loses its
special properties, even if it is subsequently reset.
-'SHELL'
+‘SHELL’
This environment variable expands to the full pathname to the
shell. If it is not set when the shell starts, Bash assigns to it
the full pathname of the current user's login shell.
-'SHELLOPTS'
+‘SHELLOPTS’
A colon-separated list of enabled shell options. Each word in the
- list is a valid argument for the '-o' option to the 'set' builtin
+ list is a valid argument for the ‘-o’ option to the ‘set’ builtin
command (*note The Set Builtin::). The options appearing in
- 'SHELLOPTS' are those reported as 'on' by 'set -o'. If this
+ ‘SHELLOPTS’ are those reported as ‘on’ by ‘set -o’. If this
variable is in the environment when Bash starts up, each shell
option in the list will be enabled before reading any startup
files. This variable is readonly.
-'SHLVL'
+‘SHLVL’
Incremented by one each time a new instance of Bash is started.
This is intended to be a count of how deeply your Bash shells are
nested.
-'SRANDOM'
+‘SRANDOM’
This variable expands to a 32-bit pseudo-random number each time it
is referenced. The random number generator is not linear on
- systems that support '/dev/urandom' or 'arc4random', so each
+ systems that support ‘/dev/urandom’ or ‘arc4random’, so each
returned number has no relationship to the numbers preceding it.
The random number generator cannot be seeded, so assignments to
- this variable have no effect. If 'SRANDOM' is unset, it loses its
+ this variable have no effect. If ‘SRANDOM’ is unset, it loses its
special properties, even if it is subsequently reset.
-'TIMEFORMAT'
+‘TIMEFORMAT’
The value of this parameter is used as a format string specifying
- how the timing information for pipelines prefixed with the 'time'
- reserved word should be displayed. The '%' character introduces an
+ how the timing information for pipelines prefixed with the ‘time’
+ reserved word should be displayed. The ‘%’ character introduces an
escape sequence that is expanded to a time value or other
information. The escape sequences and their meanings are as
- follows; the braces denote optional portions.
+ follows; the brackets denote optional portions.
- '%%'
- A literal '%'.
+ ‘%%’
+ A literal ‘%’.
- '%[P][l]R'
+ ‘%[P][l]R’
The elapsed time in seconds.
- '%[P][l]U'
+ ‘%[P][l]U’
The number of CPU seconds spent in user mode.
- '%[P][l]S'
+ ‘%[P][l]S’
The number of CPU seconds spent in system mode.
- '%P'
+ ‘%P’
The CPU percentage, computed as (%U + %S) / %R.
The optional P is a digit specifying the precision, the number of
the decimal point may be specified; values of P greater than 6 are
changed to 6. If P is not specified, the value 3 is used.
- The optional 'l' specifies a longer format, including minutes, of
+ The optional ‘l’ specifies a longer format, including minutes, of
the form MMmSS.FFs. The value of P determines whether or not the
fraction is included.
If the value is null, Bash does not display any timing information.
A trailing newline is added when the format string is displayed.
-'TMOUT'
- If set to a value greater than zero, 'TMOUT' is treated as the
- default timeout for the 'read' builtin (*note Bash Builtins::).
- The 'select' command (*note Conditional Constructs::) terminates if
- input does not arrive after 'TMOUT' seconds when input is coming
+‘TMOUT’
+ If set to a value greater than zero, ‘TMOUT’ is treated as the
+ default timeout for the ‘read’ builtin (*note Bash Builtins::).
+ The ‘select’ command (*note Conditional Constructs::) terminates if
+ input does not arrive after ‘TMOUT’ seconds when input is coming
from a terminal.
In an interactive shell, the value is interpreted as the number of
prompt. Bash terminates after waiting for that number of seconds
if a complete line of input does not arrive.
-'TMPDIR'
+‘TMPDIR’
If set, Bash uses its value as the name of a directory in which
Bash creates temporary files for the shell's use.
-'UID'
+‘UID’
The numeric real user id of the current user. This variable is
readonly.
* Bash Startup Files:: When and how Bash executes scripts.
* Interactive Shells:: What an interactive shell is.
* Bash Conditional Expressions:: Primitives used in composing expressions for
- the 'test' builtin.
+ the ‘test’ builtin.
* Shell Arithmetic:: Arithmetic on shell variables.
* Aliases:: Substituting one command for another.
* Arrays:: Array Variables.
bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o OPTION]
[-O SHOPT_OPTION] [ARGUMENT ...]
- All of the single-character options used with the 'set' builtin
+ All of the single-character options used with the ‘set’ builtin
(*note The Set Builtin::) can be used as options when the shell is
invoked. In addition, there are several multi-character options that
you can use. These options must appear on the command line before the
single-character options to be recognized.
-'--debugger'
+‘--debugger’
Arrange for the debugger profile to be executed before the shell
starts. Turns on extended debugging mode (see *note The Shopt
- Builtin:: for a description of the 'extdebug' option to the 'shopt'
+ Builtin:: for a description of the ‘extdebug’ option to the ‘shopt’
builtin).
-'--dump-po-strings'
- A list of all double-quoted strings preceded by '$' is printed on
- the standard output in the GNU 'gettext' PO (portable object) file
- format. Equivalent to '-D' except for the output format.
+‘--dump-po-strings’
+ A list of all double-quoted strings preceded by ‘$’ is printed on
+ the standard output in the GNU ‘gettext’ PO (portable object) file
+ format. Equivalent to ‘-D’ except for the output format.
-'--dump-strings'
- Equivalent to '-D'.
+‘--dump-strings’
+ Equivalent to ‘-D’.
-'--help'
+‘--help’
Display a usage message on standard output and exit successfully.
-'--init-file FILENAME'
-'--rcfile FILENAME'
- Execute commands from FILENAME (instead of '~/.bashrc') in an
+‘--init-file FILENAME’
+‘--rcfile FILENAME’
+ Execute commands from FILENAME (instead of ‘~/.bashrc’) in an
interactive shell.
-'--login'
- Equivalent to '-l'.
+‘--login’
+ Equivalent to ‘-l’.
-'--noediting'
+‘--noediting’
Do not use the GNU Readline library (*note Command Line Editing::)
to read command lines when the shell is interactive.
-'--noprofile'
- Don't load the system-wide startup file '/etc/profile' or any of
- the personal initialization files '~/.bash_profile',
- '~/.bash_login', or '~/.profile' when Bash is invoked as a login
+‘--noprofile’
+ Don't load the system-wide startup file ‘/etc/profile’ or any of
+ the personal initialization files ‘~/.bash_profile’,
+ ‘~/.bash_login’, or ‘~/.profile’ when Bash is invoked as a login
shell.
-'--norc'
- Don't read the '~/.bashrc' initialization file in an interactive
- shell. This is on by default if the shell is invoked as 'sh'.
+‘--norc’
+ Don't read the ‘~/.bashrc’ initialization file in an interactive
+ shell. This is on by default if the shell is invoked as ‘sh’.
-'--posix'
+‘--posix’
Change the behavior of Bash where the default operation differs
from the POSIX standard to match the standard. This is intended to
make Bash behave as a strict superset of that standard. *Note Bash
POSIX Mode::, for a description of the Bash POSIX mode.
-'--restricted'
- Equivalent to '-r'. Make the shell a restricted shell (*note The
+‘--restricted’
+ Equivalent to ‘-r’. Make the shell a restricted shell (*note The
Restricted Shell::).
-'--verbose'
- Equivalent to '-v'. Print shell input lines as they're read.
+‘--verbose’
+ Equivalent to ‘-v’. Print shell input lines as they're read.
-'--version'
+‘--version’
Show version information for this instance of Bash on the standard
output and exit successfully.
There are several single-character options that may be supplied at
-invocation which are not available with the 'set' builtin.
+invocation which are not available with the ‘set’ builtin.
-'-c'
+‘-c’
Read and execute commands from the first non-option argument
COMMAND_STRING, then exit. If there are arguments after the
- COMMAND_STRING, the first argument is assigned to '$0' and any
+ COMMAND_STRING, the first argument is assigned to ‘$0’ and any
remaining arguments are assigned to the positional parameters. The
- assignment to '$0' sets the name of the shell, which is used in
+ assignment to ‘$0’ sets the name of the shell, which is used in
warning and error messages.
-'-i'
+‘-i’
Force the shell to run interactively. Interactive shells are
described in *note Interactive Shells::.
-'-l'
+‘-l’
Make this shell act as if it had been directly invoked by login.
When the shell is interactive, this is equivalent to starting a
- login shell with 'exec -l bash'. When the shell is not
- interactive, the login shell startup files will be executed. 'exec
- bash -l' or 'exec bash --login' will replace the current shell with
+ login shell with ‘exec -l bash’. When the shell is not
+ interactive, the login shell startup files will be executed. ‘exec
+ bash -l’ or ‘exec bash --login’ will replace the current shell with
a Bash login shell. *Note Bash Startup Files::, for a description
of the special behavior of a login shell.
-'-r'
+‘-r’
Make the shell a restricted shell (*note The Restricted Shell::).
-'-s'
+‘-s’
If this option is present, or if no arguments remain after option
processing, then commands are read from the standard input. This
option allows the positional parameters to be set when invoking an
interactive shell or when reading input through a pipe.
-'-D'
- A list of all double-quoted strings preceded by '$' is printed on
+‘-D’
+ A list of all double-quoted strings preceded by ‘$’ is printed on
the standard output. These are the strings that are subject to
- language translation when the current locale is not 'C' or 'POSIX'
- (*note Locale Translation::). This implies the '-n' option; no
+ language translation when the current locale is not ‘C’ or ‘POSIX’
+ (*note Locale Translation::). This implies the ‘-n’ option; no
commands will be executed.
-'[-+]O [SHOPT_OPTION]'
- SHOPT_OPTION is one of the shell options accepted by the 'shopt'
+‘[-+]O [SHOPT_OPTION]’
+ SHOPT_OPTION is one of the shell options accepted by the ‘shopt’
builtin (*note The Shopt Builtin::). If SHOPT_OPTION is present,
- '-O' sets the value of that option; '+O' unsets it. If
+ ‘-O’ sets the value of that option; ‘+O’ unsets it. If
SHOPT_OPTION is not supplied, the names and values of the shell
- options accepted by 'shopt' are printed on the standard output. If
- the invocation option is '+O', the output is displayed in a format
+ options accepted by ‘shopt’ are printed on the standard output. If
+ the invocation option is ‘+O’, the output is displayed in a format
that may be reused as input.
-'--'
- A '--' signals the end of options and disables further option
- processing. Any arguments after the '--' are treated as a shell
+‘--’
+ A ‘--’ signals the end of options and disables further option
+ processing. Any arguments after the ‘--’ are treated as a shell
script filename (*note Shell Scripts::) and arguments passed to
that script.
-'-'
- Equivalent to '--'.
+‘-’
+ Equivalent to ‘--’.
- A _login_ shell is one whose first character of argument zero is '-',
-or one invoked with the '--login' option.
+ A _login_ shell is one whose first character of argument zero is ‘-’,
+or one invoked with the ‘--login’ option.
An _interactive_ shell is one started without non-option arguments,
-unless '-s' is specified, without specifying the '-c' option, and whose
+unless ‘-s’ is specified, without specifying the ‘-c’ option, and whose
input and output are both connected to terminals (as determined by
-'isatty(3)'), or one started with the '-i' option. *Note Interactive
+‘isatty(3)’), or one started with the ‘-i’ option. *Note Interactive
Shells::, for more information.
- If arguments remain after option processing, and neither the '-c' nor
-the '-s' option has been supplied, the first argument is assumed to be
+ If arguments remain after option processing, and neither the ‘-c’ nor
+the ‘-s’ option has been supplied, the first argument is assumed to be
the name of a file containing shell commands (*note Shell Scripts::).
-When Bash is invoked in this fashion, '$0' is set to the name of the
+When Bash is invoked in this fashion, ‘$0’ is set to the name of the
file, and the positional parameters are set to the remaining arguments.
Bash reads and executes commands from this file, then exits. Bash's
exit status is the exit status of the last command executed in the
Interactive shells are described in *note Interactive Shells::.
-Invoked as an interactive login shell, or with '--login'
+Invoked as an interactive login shell, or with ‘--login’
........................................................
When Bash is invoked as an interactive login shell, or as a
-non-interactive shell with the '--login' option, it first reads and
-executes commands from the file '/etc/profile', if that file exists.
-After reading that file, it looks for '~/.bash_profile',
-'~/.bash_login', and '~/.profile', in that order, and reads and executes
+non-interactive shell with the ‘--login’ option, it first reads and
+executes commands from the file ‘/etc/profile’, if that file exists.
+After reading that file, it looks for ‘~/.bash_profile’,
+‘~/.bash_login’, and ‘~/.profile’, in that order, and reads and executes
commands from the first one that exists and is readable. The
-'--noprofile' option may be used when the shell is started to inhibit
+‘--noprofile’ option may be used when the shell is started to inhibit
this behavior.
When an interactive login shell exits, or a non-interactive login
-shell executes the 'exit' builtin command, Bash reads and executes
-commands from the file '~/.bash_logout', if it exists.
+shell executes the ‘exit’ builtin command, Bash reads and executes
+commands from the file ‘~/.bash_logout’, if it exists.
Invoked as an interactive non-login shell
.........................................
When an interactive shell that is not a login shell is started, Bash
-reads and executes commands from '~/.bashrc', if that file exists. This
-may be inhibited by using the '--norc' option. The '--rcfile FILE'
+reads and executes commands from ‘~/.bashrc’, if that file exists. This
+may be inhibited by using the ‘--norc’ option. The ‘--rcfile FILE’
option will force Bash to read and execute commands from FILE instead of
-'~/.bashrc'.
+‘~/.bashrc’.
- So, typically, your '~/.bash_profile' contains the line
+ So, typically, your ‘~/.bash_profile’ contains the line
if [ -f ~/.bashrc ]; then . ~/.bashrc; fi
after (or before) any login-specific initializations.
.........................
When Bash is started non-interactively, to run a shell script, for
-example, it looks for the variable 'BASH_ENV' in the environment,
+example, it looks for the variable ‘BASH_ENV’ in the environment,
expands its value if it appears there, and uses the expanded value as
the name of a file to read and execute. Bash behaves as if the
following command were executed:
if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
-but the value of the 'PATH' variable is not used to search for the
+but the value of the ‘PATH’ variable is not used to search for the
filename.
As noted above, if a non-interactive shell is invoked with the
-'--login' option, Bash attempts to read and execute commands from the
+‘--login’ option, Bash attempts to read and execute commands from the
login shell startup files.
-Invoked with name 'sh'
+Invoked with name ‘sh’
......................
-If Bash is invoked with the name 'sh', it tries to mimic the startup
-behavior of historical versions of 'sh' as closely as possible, while
+If Bash is invoked with the name ‘sh’, it tries to mimic the startup
+behavior of historical versions of ‘sh’ as closely as possible, while
conforming to the POSIX standard as well.
When invoked as an interactive login shell, or as a non-interactive
-shell with the '--login' option, it first attempts to read and execute
-commands from '/etc/profile' and '~/.profile', in that order. The
-'--noprofile' option may be used to inhibit this behavior. When invoked
-as an interactive shell with the name 'sh', Bash looks for the variable
-'ENV', expands its value if it is defined, and uses the expanded value
+shell with the ‘--login’ option, it first attempts to read and execute
+commands from ‘/etc/profile’ and ‘~/.profile’, in that order. The
+‘--noprofile’ option may be used to inhibit this behavior. When invoked
+as an interactive shell with the name ‘sh’, Bash looks for the variable
+‘ENV’, expands its value if it is defined, and uses the expanded value
as the name of a file to read and execute. Since a shell invoked as
-'sh' does not attempt to read and execute commands from any other
-startup files, the '--rcfile' option has no effect. A non-interactive
-shell invoked with the name 'sh' does not attempt to read any other
+‘sh’ does not attempt to read and execute commands from any other
+startup files, the ‘--rcfile’ option has no effect. A non-interactive
+shell invoked with the name ‘sh’ does not attempt to read any other
startup files.
- When invoked as 'sh', Bash enters POSIX mode after the startup files
+ When invoked as ‘sh’, Bash enters POSIX mode after the startup files
are read.
Invoked in POSIX mode
.....................
-When Bash is started in POSIX mode, as with the '--posix' command line
+When Bash is started in POSIX mode, as with the ‘--posix’ command line
option, it follows the POSIX standard for startup files. In this mode,
-interactive shells expand the 'ENV' variable and commands are read and
+interactive shells expand the ‘ENV’ variable and commands are read and
executed from the file whose name is the expanded value. No other
startup files are read.
Bash attempts to determine when it is being run with its standard input
connected to a network connection, as when executed by the historical
-remote shell daemon, usually 'rshd', or the secure shell daemon 'sshd'.
+remote shell daemon, usually ‘rshd’, or the secure shell daemon ‘sshd’.
If Bash determines it is being run non-interactively in this fashion, it
-reads and executes commands from '~/.bashrc', if that file exists and is
-readable. It will not do this if invoked as 'sh'. The '--norc' option
-may be used to inhibit this behavior, and the '--rcfile' option may be
-used to force another file to be read, but neither 'rshd' nor 'sshd'
+reads and executes commands from ‘~/.bashrc’, if that file exists and is
+readable. It will not do this if invoked as ‘sh’. The ‘--norc’ option
+may be used to inhibit this behavior, and the ‘--rcfile’ option may be
+used to force another file to be read, but neither ‘rshd’ nor ‘sshd’
generally invoke the shell with those options or allow them to be
specified.
................................................
If Bash is started with the effective user (group) id not equal to the
-real user (group) id, and the '-p' option is not supplied, no startup
+real user (group) id, and the ‘-p’ option is not supplied, no startup
files are read, shell functions are not inherited from the environment,
-the 'SHELLOPTS', 'BASHOPTS', 'CDPATH', and 'GLOBIGNORE' variables, if
+the ‘SHELLOPTS’, ‘BASHOPTS’, ‘CDPATH’, and ‘GLOBIGNORE’ variables, if
they appear in the environment, are ignored, and the effective user id
-is set to the real user id. If the '-p' option is supplied at
+is set to the real user id. If the ‘-p’ option is supplied at
invocation, the startup behavior is the same, but the effective user id
is not reset.
-----------------------------------
An interactive shell is one started without non-option arguments (unless
-'-s' is specified) and without specifying the '-c' option, whose input
+‘-s’ is specified) and without specifying the ‘-c’ option, whose input
and error output are both connected to terminals (as determined by
-'isatty(3)'), or one started with the '-i' option.
+‘isatty(3)’), or one started with the ‘-i’ option.
An interactive shell generally reads from and writes to a user's
terminal.
- The '-s' invocation option may be used to set the positional
+ The ‘-s’ invocation option may be used to set the positional
parameters when an interactive shell is started.
\1f
--------------------------------
To determine within a startup script whether or not Bash is running
-interactively, test the value of the '-' special parameter. It contains
-'i' when the shell is interactive. For example:
+interactively, test the value of the ‘-’ special parameter. It contains
+‘i’ when the shell is interactive. For example:
case "$-" in
*i*) echo This shell is interactive ;;
*) echo This shell is not interactive ;;
esac
- Alternatively, startup scripts may examine the variable 'PS1'; it is
+ Alternatively, startup scripts may examine the variable ‘PS1’; it is
unset in non-interactive shells, and set in interactive shells. Thus:
if [ -z "$PS1" ]; then
2. Job Control (*note Job Control::) is enabled by default. When job
control is in effect, Bash ignores the keyboard-generated job
- control signals 'SIGTTIN', 'SIGTTOU', and 'SIGTSTP'.
+ control signals ‘SIGTTIN’, ‘SIGTTOU’, and ‘SIGTSTP’.
- 3. Bash expands and displays 'PS1' before reading the first line of a
- command, and expands and displays 'PS2' before reading the second
+ 3. Bash expands and displays ‘PS1’ before reading the first line of a
+ command, and expands and displays ‘PS2’ before reading the second
and subsequent lines of a multi-line command. Bash expands and
- displays 'PS0' after it reads a command but before executing it.
+ displays ‘PS0’ after it reads a command but before executing it.
See *note Controlling the Prompt::, for a complete list of prompt
string escape sequences.
4. Bash executes the values of the set elements of the
- 'PROMPT_COMMAND' array variable as commands before printing the
- primary prompt, '$PS1' (*note Bash Variables::).
+ ‘PROMPT_COMMAND’ array variable as commands before printing the
+ primary prompt, ‘$PS1’ (*note Bash Variables::).
5. Readline (*note Command Line Editing::) is used to read commands
from the user's terminal.
- 6. Bash inspects the value of the 'ignoreeof' option to 'set -o'
- instead of exiting immediately when it receives an 'EOF' on its
+ 6. Bash inspects the value of the ‘ignoreeof’ option to ‘set -o’
+ instead of exiting immediately when it receives an ‘EOF’ on its
standard input when reading a command (*note The Set Builtin::).
7. Command history (*note Bash History Facilities::) and history
expansion (*note History Interaction::) are enabled by default.
- Bash will save the command history to the file named by '$HISTFILE'
+ Bash will save the command history to the file named by ‘$HISTFILE’
when a shell with history enabled exits.
8. Alias expansion (*note Aliases::) is performed by default.
- 9. In the absence of any traps, Bash ignores 'SIGTERM' (*note
+ 9. In the absence of any traps, Bash ignores ‘SIGTERM’ (*note
Signals::).
- 10. In the absence of any traps, 'SIGINT' is caught and handled (*note
- Signals::). 'SIGINT' will interrupt some shell builtins.
+ 10. In the absence of any traps, ‘SIGINT’ is caught and handled (*note
+ Signals::). ‘SIGINT’ will interrupt some shell builtins.
- 11. An interactive login shell sends a 'SIGHUP' to all jobs on exit if
- the 'huponexit' shell option has been enabled (*note Signals::).
+ 11. An interactive login shell sends a ‘SIGHUP’ to all jobs on exit if
+ the ‘huponexit’ shell option has been enabled (*note Signals::).
- 12. The '-n' invocation option is ignored, and 'set -n' has no effect
+ 12. The ‘-n’ invocation option is ignored, and ‘set -n’ has no effect
(*note The Set Builtin::).
13. Bash will check for mail periodically, depending on the values of
- the 'MAIL', 'MAILPATH', and 'MAILCHECK' shell variables (*note Bash
+ the ‘MAIL’, ‘MAILPATH’, and ‘MAILCHECK’ shell variables (*note Bash
Variables::).
14. Expansion errors due to references to unbound shell variables
- after 'set -u' has been enabled will not cause the shell to exit
+ after ‘set -u’ has been enabled will not cause the shell to exit
(*note The Set Builtin::).
15. The shell will not exit on expansion errors caused by VAR being
- unset or null in '${VAR:?WORD}' expansions (*note Shell Parameter
+ unset or null in ‘${VAR:?WORD}’ expansions (*note Shell Parameter
Expansion::).
16. Redirection errors encountered by shell builtins will not cause
17. When running in POSIX mode, a special builtin returning an error
status will not cause the shell to exit (*note Bash POSIX Mode::).
- 18. A failed 'exec' will not cause the shell to exit (*note Bourne
+ 18. A failed ‘exec’ will not cause the shell to exit (*note Bourne
Shell Builtins::).
19. Parser syntax errors will not cause the shell to exit.
- 20. If the 'cdspell' shell option is enabled, the shell will attempt
- simple spelling correction for directory arguments to the 'cd'
- builtin (see the description of the 'cdspell' option to the 'shopt'
- builtin in *note The Shopt Builtin::). The 'cdspell' option is
+ 20. If the ‘cdspell’ shell option is enabled, the shell will attempt
+ simple spelling correction for directory arguments to the ‘cd’
+ builtin (see the description of the ‘cdspell’ option to the ‘shopt’
+ builtin in *note The Shopt Builtin::). The ‘cdspell’ option is
only effective in interactive shells.
- 21. The shell will check the value of the 'TMOUT' variable and exit if
+ 21. The shell will check the value of the ‘TMOUT’ variable and exit if
a command is not read within the specified number of seconds after
- printing '$PS1' (*note Bash Variables::).
+ printing ‘$PS1’ (*note Bash Variables::).
\1f
File: bash.info, Node: Bash Conditional Expressions, Next: Shell Arithmetic, Prev: Interactive Shells, Up: Bash Features
6.4 Bash Conditional Expressions
================================
-Conditional expressions are used by the '[[' compound command (*note
-Conditional Constructs::) and the 'test' and '[' builtin commands (*note
-Bourne Shell Builtins::). The 'test' and '[' commands determine their
+Conditional expressions are used by the ‘[[’ compound command (*note
+Conditional Constructs::) and the ‘test’ and ‘[’ builtin commands (*note
+Bourne Shell Builtins::). The ‘test’ and ‘[’ commands determine their
behavior based on the number of arguments; see the descriptions of those
commands for any other command-specific actions.
expressions. If the operating system on which Bash is running provides
these special files, Bash will use them; otherwise it will emulate them
internally with this behavior: If the FILE argument to one of the
-primaries is of the form '/dev/fd/N', then file descriptor N is checked.
-If the FILE argument to one of the primaries is one of '/dev/stdin',
-'/dev/stdout', or '/dev/stderr', file descriptor 0, 1, or 2,
+primaries is of the form ‘/dev/fd/N’, then file descriptor N is checked.
+If the FILE argument to one of the primaries is one of ‘/dev/stdin’,
+‘/dev/stdout’, or ‘/dev/stderr’, file descriptor 0, 1, or 2,
respectively, is checked.
- When used with '[[', the '<' and '>' operators sort lexicographically
-using the current locale. The 'test' command uses ASCII ordering.
+ When used with ‘[[’, the ‘<’ and ‘>’ operators sort lexicographically
+using the current locale. The ‘test’ command uses ASCII ordering.
Unless otherwise specified, primaries that operate on files follow
symbolic links and operate on the target of the link, rather than the
link itself.
-'-a FILE'
+‘-a FILE’
True if FILE exists.
-'-b FILE'
+‘-b FILE’
True if FILE exists and is a block special file.
-'-c FILE'
+‘-c FILE’
True if FILE exists and is a character special file.
-'-d FILE'
+‘-d FILE’
True if FILE exists and is a directory.
-'-e FILE'
+‘-e FILE’
True if FILE exists.
-'-f FILE'
+‘-f FILE’
True if FILE exists and is a regular file.
-'-g FILE'
+‘-g FILE’
True if FILE exists and its set-group-id bit is set.
-'-h FILE'
+‘-h FILE’
True if FILE exists and is a symbolic link.
-'-k FILE'
+‘-k FILE’
True if FILE exists and its "sticky" bit is set.
-'-p FILE'
+‘-p FILE’
True if FILE exists and is a named pipe (FIFO).
-'-r FILE'
+‘-r FILE’
True if FILE exists and is readable.
-'-s FILE'
+‘-s FILE’
True if FILE exists and has a size greater than zero.
-'-t FD'
+‘-t FD’
True if file descriptor FD is open and refers to a terminal.
-'-u FILE'
+‘-u FILE’
True if FILE exists and its set-user-id bit is set.
-'-w FILE'
+‘-w FILE’
True if FILE exists and is writable.
-'-x FILE'
+‘-x FILE’
True if FILE exists and is executable.
-'-G FILE'
+‘-G FILE’
True if FILE exists and is owned by the effective group id.
-'-L FILE'
+‘-L FILE’
True if FILE exists and is a symbolic link.
-'-N FILE'
+‘-N FILE’
True if FILE exists and has been modified since it was last read.
-'-O FILE'
+‘-O FILE’
True if FILE exists and is owned by the effective user id.
-'-S FILE'
+‘-S FILE’
True if FILE exists and is a socket.
-'FILE1 -ef FILE2'
+‘FILE1 -ef FILE2’
True if FILE1 and FILE2 refer to the same device and inode numbers.
-'FILE1 -nt FILE2'
+‘FILE1 -nt FILE2’
True if FILE1 is newer (according to modification date) than FILE2,
or if FILE1 exists and FILE2 does not.
-'FILE1 -ot FILE2'
+‘FILE1 -ot FILE2’
True if FILE1 is older than FILE2, or if FILE2 exists and FILE1
does not.
-'-o OPTNAME'
+‘-o OPTNAME’
True if the shell option OPTNAME is enabled. The list of options
- appears in the description of the '-o' option to the 'set' builtin
+ appears in the description of the ‘-o’ option to the ‘set’ builtin
(*note The Set Builtin::).
-'-v VARNAME'
+‘-v VARNAME’
True if the shell variable VARNAME is set (has been assigned a
value). If VARNAME is an indexed array variable name subscripted
- by '@' or '*', this returns true if the array has any set elements.
- If VARNAME is an associative array variable name subscripted by '@'
- or '*', this returns true if an element with that key is set.
+ by ‘@’ or ‘*’, this returns true if the array has any set elements.
+ If VARNAME is an associative array variable name subscripted by ‘@’
+ or ‘*’, this returns true if an element with that key is set.
-'-R VARNAME'
+‘-R VARNAME’
True if the shell variable VARNAME is set and is a name reference.
-'-z STRING'
+‘-z STRING’
True if the length of STRING is zero.
-'-n STRING'
-'STRING'
+‘-n STRING’
+‘STRING’
True if the length of STRING is non-zero.
-'STRING1 == STRING2'
-'STRING1 = STRING2'
- True if the strings are equal. When used with the '[[' command,
+‘STRING1 == STRING2’
+‘STRING1 = STRING2’
+ True if the strings are equal. When used with the ‘[[’ command,
this performs pattern matching as described above (*note
Conditional Constructs::).
- '=' should be used with the 'test' command for POSIX conformance.
+ ‘=’ should be used with the ‘test’ command for POSIX conformance.
-'STRING1 != STRING2'
+‘STRING1 != STRING2’
True if the strings are not equal.
-'STRING1 < STRING2'
+‘STRING1 < STRING2’
True if STRING1 sorts before STRING2 lexicographically.
-'STRING1 > STRING2'
+‘STRING1 > STRING2’
True if STRING1 sorts after STRING2 lexicographically.
-'ARG1 OP ARG2'
- 'OP' is one of '-eq', '-ne', '-lt', '-le', '-gt', or '-ge'. These
+‘ARG1 OP ARG2’
+ ‘OP’ is one of ‘-eq’, ‘-ne’, ‘-lt’, ‘-le’, ‘-gt’, or ‘-ge’. These
arithmetic binary operators return true if ARG1 is equal to, not
equal to, less than, less than or equal to, greater than, or
greater than or equal to ARG2, respectively. ARG1 and ARG2 may be
- positive or negative integers. When used with the '[[' command,
+ positive or negative integers. When used with the ‘[[’ command,
ARG1 and ARG2 are evaluated as arithmetic expressions (*note Shell
Arithmetic::).
====================
The shell allows arithmetic expressions to be evaluated, as one of the
-shell expansions or by using the '((' compound command, the 'let'
-builtin, or the '-i' option to the 'declare' builtin.
+shell expansions or by using the ‘((’ compound command, the ‘let’
+builtin, or the ‘-i’ option to the ‘declare’ builtin.
Evaluation is done in fixed-width integers with no check for
overflow, though division by 0 is trapped and flagged as an error. The
levels of equal-precedence operators. The levels are listed in order of
decreasing precedence.
-'ID++ ID--'
+‘ID++ ID--’
variable post-increment and post-decrement
-'++ID --ID'
+‘++ID --ID’
variable pre-increment and pre-decrement
-'- +'
+‘- +’
unary minus and plus
-'! ~'
+‘! ~’
logical and bitwise negation
-'**'
+‘**’
exponentiation
-'* / %'
+‘* / %’
multiplication, division, remainder
-'+ -'
+‘+ -’
addition, subtraction
-'<< >>'
+‘<< >>’
left and right bitwise shifts
-'<= >= < >'
+‘<= >= < >’
comparison
-'== !='
+‘== !=’
equality and inequality
-'&'
+‘&’
bitwise AND
-'^'
+‘^’
bitwise exclusive OR
-'|'
+‘|’
bitwise OR
-'&&'
+‘&&’
logical AND
-'||'
+‘||’
logical OR
-'expr ? if-true-expr : if-false-expr'
+‘expr ? if-true-expr : if-false-expr’
conditional operator
-'= *= /= %= += -= <<= >>= &= ^= |='
+‘= *= /= %= += -= <<= >>= &= ^= |=’
assignment
-'expr1 , expr2'
+‘expr1 , expr2’
comma
Shell variables are allowed as operands; parameter expansion is
evaluates to 0 when referenced by name without using the parameter
expansion syntax. The value of a variable is evaluated as an arithmetic
expression when it is referenced, or when a variable which has been
-given the 'integer' attribute using 'declare -i' is assigned a value. A
-null value evaluates to 0. A shell variable need not have its 'integer'
+given the ‘integer’ attribute using ‘declare -i’ is assigned a value. A
+null value evaluates to 0. A shell variable need not have its ‘integer’
attribute turned on to be used in an expression.
Integer constants follow the C language definition, without suffixes
or character constants. Constants with a leading 0 are interpreted as
-octal numbers. A leading '0x' or '0X' denotes hexadecimal. Otherwise,
-numbers take the form [BASE'#']N, where the optional BASE is a decimal
+octal numbers. A leading ‘0x’ or ‘0X’ denotes hexadecimal. Otherwise,
+numbers take the form [BASE‘#’]N, where the optional BASE is a decimal
number between 2 and 64 representing the arithmetic base, and N is a
-number in that base. If BASE'#' is omitted, then base 10 is used. When
+number in that base. If BASE‘#’ is omitted, then base 10 is used. When
specifying N, if a non-digit is required, the digits greater than 9 are
-represented by the lowercase letters, the uppercase letters, '@', and
-'_', in that order. If BASE is less than or equal to 36, lowercase and
+represented by the lowercase letters, the uppercase letters, ‘@’, and
+‘_’, in that order. If BASE is less than or equal to 36, lowercase and
uppercase letters may be used interchangeably to represent numbers
between 10 and 35.
6.6 Aliases
===========
-"Aliases" allow a string to be substituted for a word that is in a
+“Aliases” allow a string to be substituted for a word that is in a
position in the input where it can be the first word of a simple
command. Aliases have names and corresponding values that are set and
-unset using the 'alias' and 'unalias' builtin commands (*note Shell
+unset using the ‘alias’ and ‘unalias’ builtin commands (*note Shell
Builtin Commands::).
If the shell reads an unquoted word in the right position, it checks
had been read instead of the word. The shell doesn't look at any
characters following the word before attempting alias substitution.
- The characters '/', '$', '`', '=' and any of the shell metacharacters
+ The characters ‘/’, ‘$’, ‘`’, ‘=’ and any of the shell metacharacters
or quoting characters listed above may not appear in an alias name. The
replacement text may contain any valid shell input, including shell
metacharacters. The first word of the replacement text is tested for
aliases, but a word that is identical to an alias being expanded is not
-expanded a second time. This means that one may alias 'ls' to '"ls
--F"', for instance, and Bash does not try to recursively expand the
+expanded a second time. This means that one may alias ‘ls’ to ‘"ls
+-F"’, for instance, and Bash does not try to recursively expand the
replacement text.
- If the last character of the alias value is a 'blank', then the next
+ If the last character of the alias value is a ‘blank’, then the next
command word following the alias is also checked for alias expansion.
- Aliases are created and listed with the 'alias' command, and removed
-with the 'unalias' command.
+ Aliases are created and listed with the ‘alias’ command, and removed
+with the ‘unalias’ command.
There is no mechanism for using arguments in the replacement text, as
-in 'csh'. If arguments are needed, use a shell function (*note Shell
+in ‘csh’. If arguments are needed, use a shell function (*note Shell
Functions::) instead.
Aliases are not expanded when the shell is not interactive, unless
-the 'expand_aliases' shell option is set using 'shopt' (*note The Shopt
+the ‘expand_aliases’ shell option is set using ‘shopt’ (*note The Shopt
Builtin::).
The rules concerning the definition and use of aliases are somewhat
executed, because a function definition is itself a command. As a
consequence, aliases defined in a function are not available until after
that function is executed. To be safe, always put alias definitions on
-a separate line, and do not use 'alias' in compound commands.
+a separate line, and do not use ‘alias’ in compound commands.
For almost every purpose, shell functions are preferred over aliases.
==========
Bash provides one-dimensional indexed and associative array variables.
-Any variable may be used as an indexed array; the 'declare' builtin will
+Any variable may be used as an indexed array; the ‘declare’ builtin will
explicitly declare an array. There is no maximum limit on the size of
an array, nor any requirement that members be indexed or assigned
contiguously. Indexed arrays are referenced using integers (including
Associative arrays are created using
declare -A NAME
- Attributes may be specified for an array variable using the 'declare'
-and 'readonly' builtins. Each attribute applies to all members of an
+ Attributes may be specified for an array variable using the ‘declare’
+and ‘readonly’ builtins. Each attribute applies to all members of an
array.
Arrays are assigned to using compound assignments of the form
NAME=(VALUE1 VALUE2 ... )
-where each VALUE may be of the form '[SUBSCRIPT]='STRING. Indexed array
+where each VALUE may be of the form ‘[SUBSCRIPT]=’STRING. Indexed array
assignments do not require anything but STRING. When assigning to
indexed arrays, if the optional subscript is supplied, that index is
assigned to; otherwise the index of the element assigned is the last
using key/value pairs, the keys may not be missing or empty; a final
missing value is treated like the empty string.
- This syntax is also accepted by the 'declare' builtin. Individual
-array elements may be assigned to using the 'NAME[SUBSCRIPT]=VALUE'
+ This syntax is also accepted by the ‘declare’ builtin. Individual
+array elements may be assigned to using the ‘NAME[SUBSCRIPT]=VALUE’
syntax introduced above.
When assigning to an indexed array, if NAME is subscripted by a
than the maximum index of NAME, so negative indices count back from the
end of the array, and an index of -1 references the last element.
- The '+=' operator will append to an array variable when assigning
+ The ‘+=’ operator will append to an array variable when assigning
using the compound assignment syntax; see *note Shell Parameters::
above.
- Any element of an array may be referenced using '${NAME[SUBSCRIPT]}'.
+ Any element of an array may be referenced using ‘${NAME[SUBSCRIPT]}’.
The braces are required to avoid conflicts with the shell's filename
-expansion operators. If the SUBSCRIPT is '@' or '*', the word expands
+expansion operators. If the SUBSCRIPT is ‘@’ or ‘*’, the word expands
to all members of the array NAME, unless otherwise noted in the
description of a builtin or word expansion. These subscripts differ
only when the word appears within double quotes. If the word is
-double-quoted, '${NAME[*]}' expands to a single word with the value of
-each array member separated by the first character of the 'IFS'
-variable, and '${NAME[@]}' expands each element of NAME to a separate
-word. When there are no array members, '${NAME[@]}' expands to nothing.
+double-quoted, ‘${NAME[*]}’ expands to a single word with the value of
+each array member separated by the first character of the ‘IFS’
+variable, and ‘${NAME[@]}’ expands each element of NAME to a separate
+word. When there are no array members, ‘${NAME[@]}’ expands to nothing.
If the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the original
word, and the expansion of the last parameter is joined with the last
part of the original word. This is analogous to the expansion of the
-special parameters '@' and '*'. '${#NAME[SUBSCRIPT]}' expands to the
-length of '${NAME[SUBSCRIPT]}'. If SUBSCRIPT is '@' or '*', the
+special parameters ‘@’ and ‘*’. ‘${#NAME[SUBSCRIPT]}’ expands to the
+length of ‘${NAME[SUBSCRIPT]}’. If SUBSCRIPT is ‘@’ or ‘*’, the
expansion is the number of elements in the array. If the SUBSCRIPT used
to reference an element of an indexed array evaluates to a number less
than zero, it is interpreted as relative to one greater than the maximum
It is possible to obtain the keys (indices) of an array as well as
the values. ${!NAME[@]} and ${!NAME[*]} expand to the indices assigned
in array variable NAME. The treatment when in double quotes is similar
-to the expansion of the special parameters '@' and '*' within double
+to the expansion of the special parameters ‘@’ and ‘*’ within double
quotes.
- The 'unset' builtin is used to destroy arrays. 'unset
-NAME[SUBSCRIPT]' destroys the array element at index SUBSCRIPT.
+ The ‘unset’ builtin is used to destroy arrays. ‘unset
+NAME[SUBSCRIPT]’ destroys the array element at index SUBSCRIPT.
Negative subscripts to indexed arrays are interpreted as described
above. Unsetting the last element of an array variable does not unset
-the variable. 'unset NAME', where NAME is an array, removes the entire
-array. 'unset NAME[SUBSCRIPT]' behaves differently depending on the
-array type when given a subscript of '*' or '@'. When NAME is an
-associative array, it removes the element with key '*' or '@'. If NAME
-is an indexed array, 'unset' removes all of the elements, but does not
+the variable. ‘unset NAME’, where NAME is an array, removes the entire
+array. ‘unset NAME[SUBSCRIPT]’ behaves differently depending on the
+array type when given a subscript of ‘*’ or ‘@’. When NAME is an
+associative array, it removes the element with key ‘*’ or ‘@’. If NAME
+is an indexed array, ‘unset’ removes all of the elements, but does not
remove the array itself.
When using a variable name with a subscript as an argument to a
-command, such as with 'unset', without using the word expansion syntax
+command, such as with ‘unset’, without using the word expansion syntax
described above, the argument is subject to the shell's filename
expansion. If filename expansion is not desired, the argument should be
quoted.
- The 'declare', 'local', and 'readonly' builtins each accept a '-a'
-option to specify an indexed array and a '-A' option to specify an
-associative array. If both options are supplied, '-A' takes precedence.
-The 'read' builtin accepts a '-a' option to assign a list of words read
+ The ‘declare’, ‘local’, and ‘readonly’ builtins each accept a ‘-a’
+option to specify an indexed array and a ‘-A’ option to specify an
+associative array. If both options are supplied, ‘-A’ takes precedence.
+The ‘read’ builtin accepts a ‘-a’ option to assign a list of words read
from the standard input to an array, and can read values from the
-standard input into individual array elements. The 'set' and 'declare'
+standard input into individual array elements. The ‘set’ and ‘declare’
builtins display array values in a way that allows them to be reused as
input.
the directory stack.
The directory stack is a list of recently-visited directories. The
-'pushd' builtin adds directories to the stack as it changes the current
-directory, and the 'popd' builtin removes specified directories from the
+‘pushd’ builtin adds directories to the stack as it changes the current
+directory, and the ‘popd’ builtin removes specified directories from the
stack and changes the current directory to the directory removed. The
-'dirs' builtin displays the contents of the directory stack. The
+‘dirs’ builtin displays the contents of the directory stack. The
current directory is always the "top" of the directory stack.
The contents of the directory stack are also visible as the value of
-the 'DIRSTACK' shell variable.
+the ‘DIRSTACK’ shell variable.
\1f
File: bash.info, Node: Directory Stack Builtins, Up: The Directory Stack
6.8.1 Directory Stack Builtins
------------------------------
-'dirs'
+‘dirs’
dirs [-clpv] [+N | -N]
Display the list of currently remembered directories. Directories
- are added to the list with the 'pushd' command; the 'popd' command
+ are added to the list with the ‘pushd’ command; the ‘popd’ command
removes directories from the list. The current directory is always
the first directory in the stack.
- '-c'
+ ‘-c’
Clears the directory stack by deleting all of the elements.
- '-l'
+ ‘-l’
Produces a listing using full pathnames; the default listing
format uses a tilde to denote the home directory.
- '-p'
- Causes 'dirs' to print the directory stack with one entry per
+ ‘-p’
+ Causes ‘dirs’ to print the directory stack with one entry per
line.
- '-v'
- Causes 'dirs' to print the directory stack with one entry per
+ ‘-v’
+ Causes ‘dirs’ to print the directory stack with one entry per
line, prefixing each entry with its index in the stack.
- '+N'
+ ‘+N’
Displays the Nth directory (counting from the left of the list
- printed by 'dirs' when invoked without options), starting with
+ printed by ‘dirs’ when invoked without options), starting with
zero.
- '-N'
+ ‘-N’
Displays the Nth directory (counting from the right of the
- list printed by 'dirs' when invoked without options), starting
+ list printed by ‘dirs’ when invoked without options), starting
with zero.
-'popd'
+‘popd’
popd [-n] [+N | -N]
Removes elements from the directory stack. The elements are
- numbered from 0 starting at the first directory listed by 'dirs';
- that is, 'popd' is equivalent to 'popd +0'.
+ numbered from 0 starting at the first directory listed by ‘dirs’;
+ that is, ‘popd’ is equivalent to ‘popd +0’.
- When no arguments are given, 'popd' removes the top directory from
+ When no arguments are given, ‘popd’ removes the top directory from
the stack and changes to the new top directory.
Arguments, if supplied, have the following meanings:
- '-n'
+ ‘-n’
Suppresses the normal change of directory when removing
directories from the stack, so that only the stack is
manipulated.
- '+N'
+ ‘+N’
Removes the Nth directory (counting from the left of the list
- printed by 'dirs'), starting with zero, from the stack.
- '-N'
+ printed by ‘dirs’), starting with zero, from the stack.
+ ‘-N’
Removes the Nth directory (counting from the right of the list
- printed by 'dirs'), starting with zero, from the stack.
+ printed by ‘dirs’), starting with zero, from the stack.
- If the top element of the directory stack is modified, and the '-n'
- option was not supplied, 'popd' uses the 'cd' builtin to change to
- the directory at the top of the stack. If the 'cd' fails, 'popd'
+ If the top element of the directory stack is modified, and the ‘-n’
+ option was not supplied, ‘popd’ uses the ‘cd’ builtin to change to
+ the directory at the top of the stack. If the ‘cd’ fails, ‘popd’
returns a non-zero value.
- Otherwise, 'popd' returns an unsuccessful status if an invalid
+ Otherwise, ‘popd’ returns an unsuccessful status if an invalid
option is encountered, the directory stack is empty, or a
non-existent directory stack entry is specified.
- If the 'popd' command is successful, Bash runs 'dirs' to show the
+ If the ‘popd’ command is successful, Bash runs ‘dirs’ to show the
final contents of the directory stack, and the return status is 0.
-'pushd'
+‘pushd’
pushd [-n] [+N | -N | DIR]
Adds a directory to the top of the directory stack, or rotates the
stack, making the new top of the stack the current working
- directory. With no arguments, 'pushd' exchanges the top two
+ directory. With no arguments, ‘pushd’ exchanges the top two
elements of the directory stack.
Arguments, if supplied, have the following meanings:
- '-n'
+ ‘-n’
Suppresses the normal change of directory when rotating or
adding directories to the stack, so that only the stack is
manipulated.
- '+N'
+ ‘+N’
Brings the Nth directory (counting from the left of the list
- printed by 'dirs', starting with zero) to the top of the list
+ printed by ‘dirs’, starting with zero) to the top of the list
by rotating the stack.
- '-N'
+ ‘-N’
Brings the Nth directory (counting from the right of the list
- printed by 'dirs', starting with zero) to the top of the list
+ printed by ‘dirs’, starting with zero) to the top of the list
by rotating the stack.
- 'DIR'
+ ‘DIR’
Makes DIR be the top of the stack.
- After the stack has been modified, if the '-n' option was not
- supplied, 'pushd' uses the 'cd' builtin to change to the directory
- at the top of the stack. If the 'cd' fails, 'pushd' returns a
+ After the stack has been modified, if the ‘-n’ option was not
+ supplied, ‘pushd’ uses the ‘cd’ builtin to change to the directory
+ at the top of the stack. If the ‘cd’ fails, ‘pushd’ returns a
non-zero value.
- Otherwise, if no arguments are supplied, 'pushd' returns 0 unless
+ Otherwise, if no arguments are supplied, ‘pushd’ returns 0 unless
the directory stack is empty. When rotating the directory stack,
- 'pushd' returns 0 unless the directory stack is empty or a
+ ‘pushd’ returns 0 unless the directory stack is empty or a
non-existent directory stack element is specified.
- If the 'pushd' command is successful, Bash runs 'dirs' to show the
+ If the ‘pushd’ command is successful, Bash runs ‘dirs’ to show the
final contents of the directory stack.
\1f
6.9 Controlling the Prompt
==========================
-Bash examines the value of the array variable 'PROMPT_COMMAND' just
+Bash examines the value of the array variable ‘PROMPT_COMMAND’ just
before printing each primary prompt. If any elements in
-'PROMPT_COMMAND' are set and non-null, Bash executes each value, in
+‘PROMPT_COMMAND’ are set and non-null, Bash executes each value, in
numeric order, just as if it had been typed on the command line.
In addition, the following table describes the special characters
-which can appear in the prompt variables 'PS0', 'PS1', 'PS2', and 'PS4':
+which can appear in the prompt variables ‘PS0’, ‘PS1’, ‘PS2’, and ‘PS4’:
-'\a'
+‘\a’
A bell character.
-'\d'
+‘\d’
The date, in "Weekday Month Date" format (e.g., "Tue May 26").
-'\D{FORMAT}'
- The FORMAT is passed to 'strftime'(3) and the result is inserted
+‘\D{FORMAT}’
+ The FORMAT is passed to ‘strftime’(3) and the result is inserted
into the prompt string; an empty FORMAT results in a
locale-specific time representation. The braces are required.
-'\e'
+‘\e’
An escape character.
-'\h'
+‘\h’
The hostname, up to the first '.'.
-'\H'
+‘\H’
The hostname.
-'\j'
+‘\j’
The number of jobs currently managed by the shell.
-'\l'
+‘\l’
The basename of the shell's terminal device name.
-'\n'
+‘\n’
A newline.
-'\r'
+‘\r’
A carriage return.
-'\s'
- The name of the shell, the basename of '$0' (the portion following
+‘\s’
+ The name of the shell, the basename of ‘$0’ (the portion following
the final slash).
-'\t'
+‘\t’
The time, in 24-hour HH:MM:SS format.
-'\T'
+‘\T’
The time, in 12-hour HH:MM:SS format.
-'\@'
+‘\@’
The time, in 12-hour am/pm format.
-'\A'
+‘\A’
The time, in 24-hour HH:MM format.
-'\u'
+‘\u’
The username of the current user.
-'\v'
+‘\v’
The version of Bash (e.g., 2.00)
-'\V'
+‘\V’
The release of Bash, version + patchlevel (e.g., 2.00.0)
-'\w'
- The value of the 'PWD' shell variable ('$PWD'), with '$HOME'
- abbreviated with a tilde (uses the '$PROMPT_DIRTRIM' variable).
-'\W'
- The basename of '$PWD', with '$HOME' abbreviated with a tilde.
-'\!'
+‘\w’
+ The value of the ‘PWD’ shell variable (‘$PWD’), with ‘$HOME’
+ abbreviated with a tilde (uses the ‘$PROMPT_DIRTRIM’ variable).
+‘\W’
+ The basename of ‘$PWD’, with ‘$HOME’ abbreviated with a tilde.
+‘\!’
The history number of this command.
-'\#'
+‘\#’
The command number of this command.
-'\$'
- If the effective uid is 0, '#', otherwise '$'.
-'\NNN'
+‘\$’
+ If the effective uid is 0, ‘#’, otherwise ‘$’.
+‘\NNN’
The character whose ASCII code is the octal value NNN.
-'\\'
+‘\\’
A backslash.
-'\['
+‘\[’
Begin a sequence of non-printing characters. This could be used to
embed a terminal control sequence into the prompt.
-'\]'
+‘\]’
End a sequence of non-printing characters.
The command number and the history number are usually different: the
After the string is decoded, it is expanded via parameter expansion,
command substitution, arithmetic expansion, and quote removal, subject
-to the value of the 'promptvars' shell option (*note The Shopt
+to the value of the ‘promptvars’ shell option (*note The Shopt
Builtin::). This can have unwanted side effects if escaped portions of
the string appear within command substitution or contain characters
special to word expansion.
6.10 The Restricted Shell
=========================
-If Bash is started with the name 'rbash', or the '--restricted' or '-r'
+If Bash is started with the name ‘rbash’, or the ‘--restricted’ or ‘-r’
option is supplied at invocation, the shell becomes restricted. A
restricted shell is used to set up an environment more controlled than
-the standard shell. A restricted shell behaves identically to 'bash'
+the standard shell. A restricted shell behaves identically to ‘bash’
with the exception that the following are disallowed or not performed:
- * Changing directories with the 'cd' builtin.
- * Setting or unsetting the values of the 'SHELL', 'PATH', 'HISTFILE',
- 'ENV', or 'BASH_ENV' variables.
- * Specifying command names containing slashes.
- * Specifying a filename containing a slash as an argument to the '.'
+ • Changing directories with the ‘cd’ builtin.
+ • Setting or unsetting the values of the ‘SHELL’, ‘PATH’, ‘HISTFILE’,
+ ‘ENV’, or ‘BASH_ENV’ variables.
+ • Specifying command names containing slashes.
+ • Specifying a filename containing a slash as an argument to the ‘.’
builtin command.
- * Specifying a filename containing a slash as an argument to the
- 'history' builtin command.
- * Specifying a filename containing a slash as an argument to the '-p'
- option to the 'hash' builtin command.
- * Importing function definitions from the shell environment at
+ • Specifying a filename containing a slash as an argument to the
+ ‘history’ builtin command.
+ • Specifying a filename containing a slash as an argument to the ‘-p’
+ option to the ‘hash’ builtin command.
+ • Importing function definitions from the shell environment at
startup.
- * Parsing the value of 'SHELLOPTS' from the shell environment at
+ • Parsing the value of ‘SHELLOPTS’ from the shell environment at
startup.
- * Redirecting output using the '>', '>|', '<>', '>&', '&>', and '>>'
+ • Redirecting output using the ‘>’, ‘>|’, ‘<>’, ‘>&’, ‘&>’, and ‘>>’
redirection operators.
- * Using the 'exec' builtin to replace the shell with another command.
- * Adding or deleting builtin commands with the '-f' and '-d' options
- to the 'enable' builtin.
- * Using the 'enable' builtin command to enable disabled shell
+ • Using the ‘exec’ builtin to replace the shell with another command.
+ • Adding or deleting builtin commands with the ‘-f’ and ‘-d’ options
+ to the ‘enable’ builtin.
+ • Using the ‘enable’ builtin command to enable disabled shell
builtins.
- * Specifying the '-p' option to the 'command' builtin.
- * Turning off restricted mode with 'set +r' or 'shopt -u
- restricted_shell'.
+ • Specifying the ‘-p’ option to the ‘command’ builtin.
+ • Turning off restricted mode with ‘set +r’ or ‘shopt -u
+ restricted_shell’.
These restrictions are enforced after any startup files are read.
When a command that is found to be a shell script is executed (*note
-Shell Scripts::), 'rbash' turns off any restrictions in the shell
+Shell Scripts::), ‘rbash’ turns off any restrictions in the shell
spawned to execute the script.
The restricted shell mode is only one component of a useful
-restricted environment. It should be accompanied by setting 'PATH' to a
+restricted environment. It should be accompanied by setting ‘PATH’ to a
value that allows execution of only a few verified commands (commands
that allow shell escapes are particularly vulnerable), changing the
-current directory to a non-writable directory other than '$HOME' after
+current directory to a non-writable directory other than ‘$HOME’ after
login, not allowing the restricted shell to execute shell scripts, and
cleaning the environment of variables that cause some commands to modify
-their behavior (e.g., 'VISUAL' or 'PAGER').
+their behavior (e.g., ‘VISUAL’ or ‘PAGER’).
Modern systems provide more secure ways to implement a restricted
-environment, such as 'jails', 'zones', or 'containers'.
+environment, such as ‘jails’, ‘zones’, or ‘containers’.
\1f
File: bash.info, Node: Bash POSIX Mode, Next: Shell Compatibility Mode, Prev: The Restricted Shell, Up: Bash Features
The special builtins, which must be implemented as part of the shell
to provide the desired functionality, are specified as being part of the
-shell; examples of these are 'eval' and 'export'. Other utilities
+shell; examples of these are ‘eval’ and ‘export’. Other utilities
appear in the sections of POSIX not devoted to the shell which are
commonly (and in some cases must be) implemented as builtin commands,
-such as 'read' and 'test'. POSIX also specifies aspects of the shell's
+such as ‘read’ and ‘test’. POSIX also specifies aspects of the shell's
interactive behavior, including job control and command line editing.
Only vi-style line editing commands have been standardized; emacs
editing commands were left out due to objections.
Although Bash is an implementation of the POSIX shell specification,
there are areas where the Bash default behavior differs from the
-specification. The Bash "posix mode" changes the Bash behavior in these
+specification. The Bash “posix mode” changes the Bash behavior in these
areas so that it conforms to the standard more closely.
- Starting Bash with the '--posix' command-line option or executing
-'set -o posix' while Bash is running will cause Bash to conform more
+ Starting Bash with the ‘--posix’ command-line option or executing
+‘set -o posix’ while Bash is running will cause Bash to conform more
closely to the POSIX standard by changing the behavior to match that
specified by POSIX in areas where the Bash default differs.
- When invoked as 'sh', Bash enters POSIX mode after reading the
+ When invoked as ‘sh’, Bash enters POSIX mode after reading the
startup files.
The following list is what's changed when 'POSIX mode' is in effect:
- 1. Bash ensures that the 'POSIXLY_CORRECT' variable is set.
+ 1. Bash ensures that the ‘POSIXLY_CORRECT’ variable is set.
2. When a command in the hash table no longer exists, Bash will
- re-search '$PATH' to find the new location. This is also available
- with 'shopt -s checkhash'.
+ re-search ‘$PATH’ to find the new location. This is also available
+ with ‘shopt -s checkhash’.
3. Bash will not insert a command without the execute bit set into the
command hash table, even if it returns it as a (last-ditch) result
- from a '$PATH' search.
+ from a ‘$PATH’ search.
4. The message printed by the job control code and builtins when a job
exits with a non-zero status is 'Done(status)'.
5. The message printed by the job control code and builtins when a job
is stopped is 'Stopped(SIGNAME)', where SIGNAME is, for example,
- 'SIGTSTP'.
+ ‘SIGTSTP’.
6. Alias expansion is always enabled, even in non-interactive shells.
the command substitution is initially parsed (e.g., as part of a
function definition).
- 9. The POSIX 'PS1' and 'PS2' expansions of '!' to the history number
- and '!!' to '!' are enabled, and parameter expansion is performed
- on the values of 'PS1' and 'PS2' regardless of the setting of the
- 'promptvars' option.
+ 9. The POSIX ‘PS1’ and ‘PS2’ expansions of ‘!’ to the history number
+ and ‘!!’ to ‘!’ are enabled, and parameter expansion is performed
+ on the values of ‘PS1’ and ‘PS2’ regardless of the setting of the
+ ‘promptvars’ option.
- 10. The POSIX startup files are executed ('$ENV') rather than the
+ 10. The POSIX startup files are executed (‘$ENV’) rather than the
normal Bash files.
11. Tilde expansion is only performed on assignments preceding a
command name, rather than on all assignment statements on the line.
- 12. The default history file is '~/.sh_history' (this is the default
- value the shell assigns to '$HISTFILE').
+ 12. The default history file is ‘~/.sh_history’ (this is the default
+ value the shell assigns to ‘$HISTFILE’).
13. Redirection operators do not perform filename expansion on the
word in the redirection unless the shell is interactive.
14. Redirection operators do not perform word splitting on the word in
the redirection.
- 15. Function names must be valid shell 'name's. That is, they may not
+ 15. Function names must be valid shell ‘name’s. That is, they may not
contain characters other than letters, digits, and underscores, and
may not start with a digit. Declaring a function with an invalid
name causes a fatal syntax error in non-interactive shells.
whose name contains one or more slashes.
18. POSIX special builtins are found before shell functions during
- command lookup, including output printed by the 'type' and
- 'command' builtins.
+ command lookup, including output printed by the ‘type’ and
+ ‘command’ builtins.
- 19. When printing shell function definitions (e.g., by 'type'), Bash
- does not print the 'function' keyword.
+ 19. When printing shell function definitions (e.g., by ‘type’), Bash
+ does not print the ‘function’ keyword.
20. Literal tildes that appear as the first character in elements of
- the 'PATH' variable are not expanded as described above under *note
+ the ‘PATH’ variable are not expanded as described above under *note
Tilde Expansion::.
- 21. The 'time' reserved word may be used by itself as a command. When
+ 21. The ‘time’ reserved word may be used by itself as a command. When
used in this way, it displays timing statistics for the shell and
- its completed children. The 'TIMEFORMAT' variable controls the
+ its completed children. The ‘TIMEFORMAT’ variable controls the
format of the timing information.
22. When parsing and expanding a ${...} expansion that appears within
the operator is one of those defined to perform pattern removal.
In this case, they do not have to appear as matched pairs.
- 23. The parser does not recognize 'time' as a reserved word if the
- next token begins with a '-'.
+ 23. The parser does not recognize ‘time’ as a reserved word if the
+ next token begins with a ‘-’.
- 24. The '!' character does not introduce history expansion within a
- double-quoted string, even if the 'histexpand' option is enabled.
+ 24. The ‘!’ character does not introduce history expansion within a
+ double-quoted string, even if the ‘histexpand’ option is enabled.
25. If a POSIX special builtin returns an error status, a
non-interactive shell exits. The fatal errors are those listed in
options, redirection errors, variable assignment errors for
assignments preceding the command name, and so on.
- 26. The 'unset' builtin with the '-v' option specified returns a fatal
- error if it attempts to unset a 'readonly' or 'non-unsettable'
+ 26. The ‘unset’ builtin with the ‘-v’ option specified returns a fatal
+ error if it attempts to unset a ‘readonly’ or ‘non-unsettable’
variable, or encounters a variable name argument that is an invalid
identifier, which causes a non-interactive shell to exit.
27. When asked to unset a variable that appears in an assignment
- statement preceding the command, the 'unset' builtin attempts to
+ statement preceding the command, the ‘unset’ builtin attempts to
unset a variable of the same name in the current or previous scope
as well. This implements the required "if an assigned variable is
further modified by the utility, the modifications made by the
occurred").
30. A non-interactive shell exits with an error status if the
- iteration variable in a 'for' statement or the selection variable
- in a 'select' statement is a readonly variable or has an invalid
+ iteration variable in a ‘for’ statement or the selection variable
+ in a ‘select’ statement is a readonly variable or has an invalid
name.
- 31. Non-interactive shells exit if FILENAME in '.' FILENAME is not
+ 31. Non-interactive shells exit if FILENAME in ‘.’ FILENAME is not
found.
32. Non-interactive shells exit if a syntax error in an arithmetic
33. Non-interactive shells exit if a parameter expansion error occurs.
34. Non-interactive shells exit if there is a syntax error in a script
- read with the '.' or 'source' builtins, or in a string processed by
- the 'eval' builtin.
+ read with the ‘.’ or ‘source’ builtins, or in a string processed by
+ the ‘eval’ builtin.
35. While variable indirection is available, it may not be applied to
- the '#' and '?' special parameters.
+ the ‘#’ and ‘?’ special parameters.
- 36. Expanding the '*' special parameter in a pattern context where the
- expansion is double-quoted does not treat the '$*' as if it were
+ 36. Expanding the ‘*’ special parameter in a pattern context where the
+ expansion is double-quoted does not treat the ‘$*’ as if it were
double-quoted.
37. Assignment statements preceding POSIX special builtins persist in
the shell environment after the builtin completes.
- 38. The 'command' builtin does not prevent builtins that take
+ 38. The ‘command’ builtin does not prevent builtins that take
assignment statements as arguments from expanding them as
assignment statements; when not in POSIX mode, assignment builtins
lose their assignment statement expansion properties when preceded
- by 'command'.
+ by ‘command’.
- 39. The 'bg' builtin uses the required format to describe each job
+ 39. The ‘bg’ builtin uses the required format to describe each job
placed in the background, which does not include an indication of
whether the job is the current or previous job.
- 40. The output of 'kill -l' prints all the signal names on a single
- line, separated by spaces, without the 'SIG' prefix.
+ 40. The output of ‘kill -l’ prints all the signal names on a single
+ line, separated by spaces, without the ‘SIG’ prefix.
- 41. The 'kill' builtin does not accept signal names with a 'SIG'
+ 41. The ‘kill’ builtin does not accept signal names with a ‘SIG’
prefix.
- 42. The 'export' and 'readonly' builtin commands display their output
+ 42. The ‘export’ and ‘readonly’ builtin commands display their output
in the format required by POSIX.
- 43. If the 'export' and 'readonly' builtin commands get an argument
+ 43. If the ‘export’ and ‘readonly’ builtin commands get an argument
that is not a valid identifier, and they are not operating on shell
functions, they return an error. This will cause a non-interactive
shell to exit because these are special builtins.
- 44. The 'trap' builtin displays signal names without the leading
- 'SIG'.
+ 44. The ‘trap’ builtin displays signal names without the leading
+ ‘SIG’.
- 45. The 'trap' builtin doesn't check the first argument for a possible
+ 45. The ‘trap’ builtin doesn't check the first argument for a possible
signal specification and revert the signal handling to the original
disposition if it is, unless that argument consists solely of
digits and is a valid signal number. If users want to reset the
handler for a given signal to the original disposition, they should
- use '-' as the first argument.
+ use ‘-’ as the first argument.
- 46. 'trap -p' without arguments displays signals whose dispositions
+ 46. ‘trap -p’ without arguments displays signals whose dispositions
are set to SIG_DFL and those that were ignored when the shell
started, not just trapped signals.
- 47. The '.' and 'source' builtins do not search the current directory
- for the filename argument if it is not found by searching 'PATH'.
+ 47. The ‘.’ and ‘source’ builtins do not search the current directory
+ for the filename argument if it is not found by searching ‘PATH’.
48. Enabling POSIX mode has the effect of setting the
- 'inherit_errexit' option, so subshells spawned to execute command
- substitutions inherit the value of the '-e' option from the parent
- shell. When the 'inherit_errexit' option is not enabled, Bash
- clears the '-e' option in such subshells.
+ ‘inherit_errexit’ option, so subshells spawned to execute command
+ substitutions inherit the value of the ‘-e’ option from the parent
+ shell. When the ‘inherit_errexit’ option is not enabled, Bash
+ clears the ‘-e’ option in such subshells.
- 49. Enabling POSIX mode has the effect of setting the 'shift_verbose'
- option, so numeric arguments to 'shift' that exceed the number of
+ 49. Enabling POSIX mode has the effect of setting the ‘shift_verbose’
+ option, so numeric arguments to ‘shift’ that exceed the number of
positional parameters will result in an error message.
- 50. When the 'alias' builtin displays alias definitions, it does not
- display them with a leading 'alias ' unless the '-p' option is
+ 50. When the ‘alias’ builtin displays alias definitions, it does not
+ display them with a leading ‘alias ’ unless the ‘-p’ option is
supplied.
- 51. When the 'set' builtin is invoked without options, it does not
+ 51. When the ‘set’ builtin is invoked without options, it does not
display shell function names and definitions.
- 52. When the 'set' builtin is invoked without options, it displays
+ 52. When the ‘set’ builtin is invoked without options, it displays
variable values without quotes, unless they contain shell
metacharacters, even if the result contains nonprinting characters.
- 53. When the 'cd' builtin is invoked in logical mode, and the pathname
- constructed from '$PWD' and the directory name supplied as an
- argument does not refer to an existing directory, 'cd' will fail
+ 53. When the ‘cd’ builtin is invoked in logical mode, and the pathname
+ constructed from ‘$PWD’ and the directory name supplied as an
+ argument does not refer to an existing directory, ‘cd’ will fail
instead of falling back to physical mode.
- 54. When the 'cd' builtin cannot change a directory because the length
- of the pathname constructed from '$PWD' and the directory name
- supplied as an argument exceeds 'PATH_MAX' when all symbolic links
- are expanded, 'cd' will fail instead of attempting to use only the
+ 54. When the ‘cd’ builtin cannot change a directory because the length
+ of the pathname constructed from ‘$PWD’ and the directory name
+ supplied as an argument exceeds ‘PATH_MAX’ when all symbolic links
+ are expanded, ‘cd’ will fail instead of attempting to use only the
supplied directory name.
- 55. The 'pwd' builtin verifies that the value it prints is the same as
+ 55. The ‘pwd’ builtin verifies that the value it prints is the same as
the current directory, even if it is not asked to check the file
- system with the '-P' option.
+ system with the ‘-P’ option.
- 56. When listing the history, the 'fc' builtin does not include an
+ 56. When listing the history, the ‘fc’ builtin does not include an
indication of whether or not a history entry has been modified.
- 57. The default editor used by 'fc' is 'ed'.
+ 57. The default editor used by ‘fc’ is ‘ed’.
- 58. If there are too many arguments supplied to 'fc -s', 'fc' prints
+ 58. If there are too many arguments supplied to ‘fc -s’, ‘fc’ prints
an error message and returns failure.
- 59. The 'type' and 'command' builtins will not report a non-executable
+ 59. The ‘type’ and ‘command’ builtins will not report a non-executable
file as having been found, though the shell will attempt to execute
- such a file if it is the only so-named file found in '$PATH'.
+ such a file if it is the only so-named file found in ‘$PATH’.
- 60. The 'vi' editing mode will invoke the 'vi' editor directly when
- the 'v' command is run, instead of checking '$VISUAL' and
- '$EDITOR'.
+ 60. The ‘vi’ editing mode will invoke the ‘vi’ editor directly when
+ the ‘v’ command is run, instead of checking ‘$VISUAL’ and
+ ‘$EDITOR’.
- 61. When the 'xpg_echo' option is enabled, Bash does not attempt to
- interpret any arguments to 'echo' as options. Each argument is
+ 61. When the ‘xpg_echo’ option is enabled, Bash does not attempt to
+ interpret any arguments to ‘echo’ as options. Each argument is
displayed, after escape characters are converted.
- 62. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
- and '-f' options.
+ 62. The ‘ulimit’ builtin uses a block size of 512 bytes for the ‘-c’
+ and ‘-f’ options.
- 63. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
- interrupt the 'wait' builtin and cause it to return immediately.
+ 63. The arrival of ‘SIGCHLD’ when a trap is set on ‘SIGCHLD’ does not
+ interrupt the ‘wait’ builtin and cause it to return immediately.
The trap command is run once for each child that exits.
- 64. The 'read' builtin may be interrupted by a signal for which a trap
+ 64. The ‘read’ builtin may be interrupted by a signal for which a trap
has been set. If Bash receives a trapped signal while executing
- 'read', the trap handler executes and 'read' returns an exit status
+ ‘read’, the trap handler executes and ‘read’ returns an exit status
greater than 128.
- 65. The 'printf' builtin uses 'double' (via 'strtod') to convert
+ 65. The ‘printf’ builtin uses ‘double’ (via ‘strtod’) to convert
arguments corresponding to floating point conversion specifiers,
- instead of 'long double' if it's available. The 'L' length
- modifier forces 'printf' to use 'long double' if it's available.
+ instead of ‘long double’ if it's available. The ‘L’ length
+ modifier forces ‘printf’ to use ‘long double’ if it's available.
66. Bash removes an exited background process's status from the list
- of such statuses after the 'wait' builtin is used to obtain it.
+ of such statuses after the ‘wait’ builtin is used to obtain it.
- 67. A double quote character ('"') is treated specially when it
+ 67. A double quote character (‘"’) is treated specially when it
appears in a backquoted command substitution in the body of a
here-document that undergoes expansion. That means, for example,
that a backslash preceding a double quote character will escape it
and the backslash will be removed.
- 68. The 'test' builtin compares strings using the current locale when
- processing the '<' and '>' binary operators.
+ 68. The ‘test’ builtin compares strings using the current locale when
+ processing the ‘<’ and ‘>’ binary operators.
- 69. The 'test' builtin's '-t' unary primary requires an argument.
- Historical versions of 'test' made the argument optional in certain
+ 69. The ‘test’ builtin's ‘-t’ unary primary requires an argument.
+ Historical versions of ‘test’ made the argument optional in certain
cases, and Bash attempts to accommodate those for backwards
compatibility.
- 70. Command substitutions don't set the '?' special parameter. The
+ 70. Command substitutions don't set the ‘?’ special parameter. The
exit status of a simple command without a command word is still the
exit status of the last command substitution that occurred while
evaluating the variable assignments and redirections in that
There is other POSIX behavior that Bash does not implement by default
even when in POSIX mode. Specifically:
- 1. The 'fc' builtin checks '$EDITOR' as a program to edit history
- entries if 'FCEDIT' is unset, rather than defaulting directly to
- 'ed'. 'fc' uses 'ed' if 'EDITOR' is unset.
+ 1. The ‘fc’ builtin checks ‘$EDITOR’ as a program to edit history
+ entries if ‘FCEDIT’ is unset, rather than defaulting directly to
+ ‘ed’. ‘fc’ uses ‘ed’ if ‘EDITOR’ is unset.
2. A non-interactive shell does not exit if a variable assignment
- preceding the 'command' builtin or another non-special builtin
+ preceding the ‘command’ builtin or another non-special builtin
fails.
- 3. As noted above, Bash requires the 'xpg_echo' option to be enabled
- for the 'echo' builtin to be fully conformant.
+ 3. As noted above, Bash requires the ‘xpg_echo’ option to be enabled
+ for the ‘echo’ builtin to be fully conformant.
Bash can be configured to be POSIX-conformant by default, by
-specifying the '--enable-strict-posix-default' to 'configure' when
+specifying the ‘--enable-strict-posix-default’ to ‘configure’ when
building (*note Optional Features::).
\1f
6.12 Shell Compatibility Mode
=============================
-Bash-4.0 introduced the concept of a "shell compatibility level",
-specified as a set of options to the shopt builtin ('compat31',
-'compat32', 'compat40', 'compat41', and so on). There is only one
+Bash-4.0 introduced the concept of a “shell compatibility level”,
+specified as a set of options to the shopt builtin (‘compat31’,
+‘compat32’, ‘compat40’, ‘compat41’, and so on). There is only one
current compatibility level - each option is mutually exclusive. The
compatibility level is intended to allow users to select behavior from
previous versions that is incompatible with newer versions while they
be a temporary solution.
This section does not mention behavior that is standard for a
-particular version (e.g., setting 'compat32' means that quoting the rhs
+particular version (e.g., setting ‘compat32’ means that quoting the rhs
of the regexp matching operator quotes special regexp characters in the
word, which is default behavior in bash-3.2 and subsequent versions).
- If a user enables, say, 'compat32', it may affect the behavior of
+ If a user enables, say, ‘compat32’, it may affect the behavior of
other compatibility levels up to and including the current compatibility
level. The idea is that each compatibility level controls behavior that
changed in that version of Bash, but that behavior may have been present
in earlier versions. For instance, the change to use locale-based
-comparisons with the '[[' command came in bash-4.1, and earlier versions
-used ASCII-based comparisons, so enabling 'compat32' will enable
+comparisons with the ‘[[’ command came in bash-4.1, and earlier versions
+used ASCII-based comparisons, so enabling ‘compat32’ will enable
ASCII-based comparisons as well. That granularity may not be sufficient
for all uses, and as a result users should employ compatibility levels
carefully. Read the documentation for a particular feature to find out
the current behavior.
- Bash-4.3 introduced a new shell variable: 'BASH_COMPAT'. The value
+ Bash-4.3 introduced a new shell variable: ‘BASH_COMPAT’. The value
assigned to this variable (a decimal version number like 4.2, or an
-integer corresponding to the 'compat'NN option, like 42) determines the
+integer corresponding to the ‘compat’NN option, like 42) determines the
compatibility level.
Starting with bash-4.4, Bash has begun deprecating older
compatibility levels. Eventually, the options will be removed in favor
-of 'BASH_COMPAT'.
+of ‘BASH_COMPAT’.
Bash-5.0 was the final version for which there will be an individual
shopt option for the previous version. Users should control the
-compatibility level with 'BASH_COMPAT'.
+compatibility level with ‘BASH_COMPAT’.
The following table describes the behavior changes controlled by each
-compatibility level setting. The 'compat'NN tag is used as shorthand
+compatibility level setting. The ‘compat’NN tag is used as shorthand
for setting the compatibility level to NN using one of the following
mechanisms. For versions prior to bash-5.0, the compatibility level may
-be set using the corresponding 'compat'NN shopt option. For bash-4.3
-and later versions, the 'BASH_COMPAT' variable is preferred, and it is
+be set using the corresponding ‘compat’NN shopt option. For bash-4.3
+and later versions, the ‘BASH_COMPAT’ variable is preferred, and it is
required for bash-5.1 and later versions.
-'compat31'
- * quoting the rhs of the '[[' command's regexp matching operator
+‘compat31’
+ • quoting the rhs of the ‘[[’ command's regexp matching operator
(=~) has no special effect
-'compat40'
- * the '<' and '>' operators to the '[[' command do not consider
+‘compat40’
+ • the ‘<’ and ‘>’ operators to the ‘[[’ command do not consider
the current locale when comparing strings; they use ASCII
ordering. Bash versions prior to bash-4.1 use ASCII collation
and strcmp(3); bash-4.1 and later use the current locale's
collation sequence and strcoll(3).
-'compat41'
- * in posix mode, 'time' may be followed by options and still be
+‘compat41’
+ • in posix mode, ‘time’ may be followed by options and still be
recognized as a reserved word (this is POSIX interpretation
267)
- * in posix mode, the parser requires that an even number of
+ • in posix mode, the parser requires that an even number of
single quotes occur in the WORD portion of a double-quoted
${...} parameter expansion and treats them specially, so that
characters within the single quotes are considered quoted
(this is POSIX interpretation 221)
-'compat42'
- * the replacement string in double-quoted pattern substitution
+‘compat42’
+ • the replacement string in double-quoted pattern substitution
does not undergo quote removal, as it does in versions after
bash-4.2
- * in posix mode, single quotes are considered special when
+ • in posix mode, single quotes are considered special when
expanding the WORD portion of a double-quoted ${...} parameter
expansion and can be used to quote a closing brace or other
special character (this is part of POSIX interpretation 221);
in later versions, single quotes are not special within
double-quoted word expansions
-'compat43'
- * the shell does not print a warning message if an attempt is
+‘compat43’
+ • the shell does not print a warning message if an attempt is
made to use a quoted compound assignment as an argument to
declare (e.g., declare -a foo='(1 2)'). Later versions warn
that this usage is deprecated
- * word expansion errors are considered non-fatal errors that
+ • word expansion errors are considered non-fatal errors that
cause the current command to fail, even in posix mode (the
default behavior is to make them fatal errors that cause the
shell to exit)
- * when executing a shell function, the loop state
- (while/until/etc.) is not reset, so 'break' or 'continue' in
+ • when executing a shell function, the loop state
+ (while/until/etc.) is not reset, so ‘break’ or ‘continue’ in
that function will break or continue loops in the calling
context. Bash-4.4 and later reset the loop state to prevent
this
-'compat44'
- * the shell sets up the values used by 'BASH_ARGV' and
- 'BASH_ARGC' so they can expand to the shell's positional
+‘compat44’
+ • the shell sets up the values used by ‘BASH_ARGV’ and
+ ‘BASH_ARGC’ so they can expand to the shell's positional
parameters even if extended debugging mode is not enabled
- * a subshell inherits loops from its parent context, so 'break'
- or 'continue' will cause the subshell to exit. Bash-5.0 and
+ • a subshell inherits loops from its parent context, so ‘break’
+ or ‘continue’ will cause the subshell to exit. Bash-5.0 and
later reset the loop state to prevent the exit
- * variable assignments preceding builtins like 'export' and
- 'readonly' that set attributes continue to affect variables
+ • variable assignments preceding builtins like ‘export’ and
+ ‘readonly’ that set attributes continue to affect variables
with the same name in the calling environment even if the
shell is not in posix mode
-'compat50 (set using BASH_COMPAT)'
- * Bash-5.1 changed the way '$RANDOM' is generated to introduce
+‘compat50 (set using BASH_COMPAT)’
+ • Bash-5.1 changed the way ‘$RANDOM’ is generated to introduce
slightly more randomness. If the shell compatibility level is
set to 50 or lower, it reverts to the method from bash-5.0 and
previous versions, so seeding the random number generator by
- assigning a value to 'RANDOM' will produce the same sequence
+ assigning a value to ‘RANDOM’ will produce the same sequence
as in bash-5.0
- * If the command hash table is empty, Bash versions prior to
+ • If the command hash table is empty, Bash versions prior to
bash-5.1 printed an informational message to that effect, even
when producing output that can be reused as input. Bash-5.1
- suppresses that message when the '-l' option is supplied.
+ suppresses that message when the ‘-l’ option is supplied.
-'compat51 (set using BASH_COMPAT)'
- * The 'unset' builtin will unset the array 'a' given an argument
- like 'a[@]'. Bash-5.2 will unset an element with key '@'
+‘compat51 (set using BASH_COMPAT)’
+ • The ‘unset’ builtin will unset the array ‘a’ given an argument
+ like ‘a[@]’. Bash-5.2 will unset an element with key ‘@’
(associative arrays) or remove all the elements without
unsetting the array (indexed arrays)
- * arithmetic commands ( ((...)) ) and the expressions in an
+ • arithmetic commands ( ((...)) ) and the expressions in an
arithmetic for statement can be expanded more than once
- * expressions used as arguments to arithmetic operators in the
- '[[' conditional command can be expanded more than once
- * the expressions in substring parameter brace expansion can be
+ • expressions used as arguments to arithmetic operators in the
+ ‘[[’ conditional command can be expanded more than once
+ • the expressions in substring parameter brace expansion can be
expanded more than once
- * the expressions in the $(( ... )) word expansion can be
+ • the expressions in the $(( ... )) word expansion can be
expanded more than once
- * arithmetic expressions used as indexed array subscripts can be
+ • arithmetic expressions used as indexed array subscripts can be
expanded more than once
- * 'test -v', when given an argument of 'A[@]', where A is an
+ • ‘test -v’, when given an argument of ‘A[@]’, where A is an
existing associative array, will return true if the array has
any set elements. Bash-5.2 will look for and report on a key
- named '@'
- * the ${PARAMETER[:]=VALUE} word expansion will return VALUE,
+ named ‘@’
+ • the ${PARAMETER[:]=VALUE} word expansion will return VALUE,
before any variable-specific transformations have been
performed (e.g., converting to lowercase). Bash-5.2 will
return the final value assigned to the variable.
- * Parsing command substitutions will behave as if extended
+ • Parsing command substitutions will behave as if extended
globbing (*note The Shopt Builtin::) is enabled, so that
parsing a command substitution containing an extglob pattern
(say, as part of a shell function) will not fail. This
driver and Bash.
The shell associates a JOB with each pipeline. It keeps a table of
-currently executing jobs, which may be listed with the 'jobs' command.
+currently executing jobs, which may be listed with the ‘jobs’ command.
When Bash starts a job asynchronously, it prints a line that looks like:
[1] 25647
indicating that this job is job number 1 and that the process ID of the
control, the operating system maintains the notion of a current terminal
process group ID. Members of this process group (processes whose
process group ID is equal to the current terminal process group ID)
-receive keyboard-generated signals such as 'SIGINT'. These processes
+receive keyboard-generated signals such as ‘SIGINT’. These processes
are said to be in the foreground. Background processes are those whose
process group ID differs from the terminal's; such processes are immune
to keyboard-generated signals. Only foreground processes are allowed to
-read from or, if the user so specifies with 'stty tostop', write to the
+read from or, if the user so specifies with ‘stty tostop’, write to the
terminal. Background processes which attempt to read from (write to
-when 'stty tostop' is in effect) the terminal are sent a 'SIGTTIN'
-('SIGTTOU') signal by the kernel's terminal driver, which, unless
+when ‘tostop’ is in effect) the terminal are sent a ‘SIGTTIN’
+(‘SIGTTOU’) signal by the kernel's terminal driver, which, unless
caught, suspends the process.
If the operating system on which Bash is running supports job
-control, Bash contains facilities to use it. Typing the "suspend"
-character (typically '^Z', Control-Z) while a process is running causes
+control, Bash contains facilities to use it. Typing the “suspend”
+character (typically ‘^Z’, Control-Z) while a process is running causes
that process to be stopped and returns control to Bash. Typing the
-"delayed suspend" character (typically '^Y', Control-Y) causes the
+“delayed suspend” character (typically ‘^Y’, Control-Y) causes the
process to be stopped when it attempts to read input from the terminal,
and control to be returned to Bash. The user then manipulates the state
-of this job, using the 'bg' command to continue it in the background,
-the 'fg' command to continue it in the foreground, or the 'kill' command
-to kill it. A '^Z' takes effect immediately, and has the additional
+of this job, using the ‘bg’ command to continue it in the background,
+the ‘fg’ command to continue it in the foreground, or the ‘kill’ command
+to kill it. A ‘^Z’ takes effect immediately, and has the additional
side effect of causing pending output and typeahead to be discarded.
There are a number of ways to refer to a job in the shell. The
-character '%' introduces a job specification ("jobspec").
+character ‘%’ introduces a job specification (“jobspec”).
- Job number 'n' may be referred to as '%n'. The symbols '%%' and '%+'
+ Job number ‘n’ may be referred to as ‘%n’. The symbols ‘%%’ and ‘%+’
refer to the shell's notion of the current job, which is the last job
stopped while it was in the foreground or started in the background. A
-single '%' (with no accompanying job specification) also refers to the
-current job. The previous job may be referenced using '%-'. If there
-is only a single job, '%+' and '%-' can both be used to refer to that
-job. In output pertaining to jobs (e.g., the output of the 'jobs'
-command), the current job is always flagged with a '+', and the previous
-job with a '-'.
+single ‘%’ (with no accompanying job specification) also refers to the
+current job. The previous job may be referenced using ‘%-’. If there
+is only a single job, ‘%+’ and ‘%-’ can both be used to refer to that
+job. In output pertaining to jobs (e.g., the output of the ‘jobs’
+command), the current job is always flagged with a ‘+’, and the previous
+job with a ‘-’.
A job may also be referred to using a prefix of the name used to
start it, or using a substring that appears in its command line. For
-example, '%ce' refers to a stopped job whose command name begins with
-'ce'. Using '%?ce', on the other hand, refers to any job containing the
-string 'ce' in its command line. If the prefix or substring matches
+example, ‘%ce’ refers to a stopped job whose command name begins with
+‘ce’. Using ‘%?ce’, on the other hand, refers to any job containing the
+string ‘ce’ in its command line. If the prefix or substring matches
more than one job, Bash reports an error.
- Simply naming a job can be used to bring it into the foreground: '%1'
-is a synonym for 'fg %1', bringing job 1 from the background into the
-foreground. Similarly, '%1 &' resumes job 1 in the background,
-equivalent to 'bg %1'
+ Simply naming a job can be used to bring it into the foreground: ‘%1’
+is a synonym for ‘fg %1’, bringing job 1 from the background into the
+foreground. Similarly, ‘%1 &’ resumes job 1 in the background,
+equivalent to ‘bg %1’
The shell learns immediately whenever a job changes state. Normally,
Bash waits until it is about to print a prompt before reporting changes
-in a job's status so as to not interrupt any other output. If the '-b'
-option to the 'set' builtin is enabled, Bash reports such changes
-immediately (*note The Set Builtin::). Any trap on 'SIGCHLD' is
+in a job's status so as to not interrupt any other output. If the ‘-b’
+option to the ‘set’ builtin is enabled, Bash reports such changes
+immediately (*note The Set Builtin::). Any trap on ‘SIGCHLD’ is
executed for each child process that exits.
If an attempt to exit Bash is made while jobs are stopped, (or
-running, if the 'checkjobs' option is enabled - see *note The Shopt
-Builtin::), the shell prints a warning message, and if the 'checkjobs'
-option is enabled, lists the jobs and their statuses. The 'jobs'
+running, if the ‘checkjobs’ option is enabled - see *note The Shopt
+Builtin::), the shell prints a warning message, and if the ‘checkjobs’
+option is enabled, lists the jobs and their statuses. The ‘jobs’
command may then be used to inspect their status. If a second attempt
to exit is made without an intervening command, Bash does not print
another warning, and any stopped jobs are terminated.
- When the shell is waiting for a job or process using the 'wait'
-builtin, and job control is enabled, 'wait' will return when the job
-changes state. The '-f' option causes 'wait' to wait until the job or
+ When the shell is waiting for a job or process using the ‘wait’
+builtin, and job control is enabled, ‘wait’ will return when the job
+changes state. The ‘-f’ option causes ‘wait’ to wait until the job or
process terminates before returning.
\1f
7.2 Job Control Builtins
========================
-'bg'
+‘bg’
bg [JOBSPEC ...]
Resume each suspended job JOBSPEC in the background, as if it had
- been started with '&'. If JOBSPEC is not supplied, the current job
+ been started with ‘&’. If JOBSPEC is not supplied, the current job
is used. The return status is zero unless it is run when job
control is not enabled, or, when run with job control enabled, any
JOBSPEC was not found or specifies a job that was started without
job control.
-'fg'
+‘fg’
fg [JOBSPEC]
Resume the job JOBSPEC in the foreground and make it the current
control enabled, JOBSPEC does not specify a valid job or JOBSPEC
specifies a job that was started without job control.
-'jobs'
+‘jobs’
jobs [-lnprs] [JOBSPEC]
jobs -x COMMAND [ARGUMENTS]
The first form lists the active jobs. The options have the
following meanings:
- '-l'
+ ‘-l’
List process IDs in addition to the normal information.
- '-n'
+ ‘-n’
Display information only about jobs that have changed status
since the user was last notified of their status.
- '-p'
+ ‘-p’
List only the process ID of the job's process group leader.
- '-r'
+ ‘-r’
Display only running jobs.
- '-s'
+ ‘-s’
Display only stopped jobs.
If JOBSPEC is given, output is restricted to information about that
job. If JOBSPEC is not supplied, the status of all jobs is listed.
- If the '-x' option is supplied, 'jobs' replaces any JOBSPEC found
+ If the ‘-x’ option is supplied, ‘jobs’ replaces any JOBSPEC found
in COMMAND or ARGUMENTS with the corresponding process group ID,
and executes COMMAND, passing it ARGUMENTs, returning its exit
status.
-'kill'
+‘kill’
kill [-s SIGSPEC] [-n SIGNUM] [-SIGSPEC] JOBSPEC or PID
kill -l|-L [EXIT_STATUS]
Send a signal specified by SIGSPEC or SIGNUM to the process named
by job specification JOBSPEC or process ID PID. SIGSPEC is either
- a case-insensitive signal name such as 'SIGINT' (with or without
- the 'SIG' prefix) or a signal number; SIGNUM is a signal number.
- If SIGSPEC and SIGNUM are not present, 'SIGTERM' is used. The '-l'
+ a case-insensitive signal name such as ‘SIGINT’ (with or without
+ the ‘SIG’ prefix) or a signal number; SIGNUM is a signal number.
+ If SIGSPEC and SIGNUM are not present, ‘SIGTERM’ is used. The ‘-l’
option lists the signal names. If any arguments are supplied when
- '-l' is given, the names of the signals corresponding to the
+ ‘-l’ is given, the names of the signals corresponding to the
arguments are listed, and the return status is zero. EXIT_STATUS
is a number specifying a signal number or the exit status of a
- process terminated by a signal. The '-L' option is equivalent to
- '-l'. The return status is zero if at least one signal was
+ process terminated by a signal. The ‘-L’ option is equivalent to
+ ‘-l’. The return status is zero if at least one signal was
successfully sent, or non-zero if an error occurs or an invalid
option is encountered.
-'wait'
+‘wait’
wait [-fn] [-p VARNAME] [JOBSPEC or PID ...]
Wait until the child process specified by each process ID PID or
job specification JOBSPEC exits and return the exit status of the
last command waited for. If a job spec is given, all processes in
- the job are waited for. If no arguments are given, 'wait' waits
+ the job are waited for. If no arguments are given, ‘wait’ waits
for all running background jobs and the last-executed process
substitution, if its process id is the same as $!, and the return
- status is zero. If the '-n' option is supplied, 'wait' waits for a
+ status is zero. If the ‘-n’ option is supplied, ‘wait’ waits for a
single job from the list of PIDs or JOBSPECs or, if no arguments
are supplied, any job, to complete and returns its exit status. If
none of the supplied arguments is a child of the shell, or if no
arguments are supplied and the shell has no unwaited-for children,
- the exit status is 127. If the '-p' option is supplied, the
+ the exit status is 127. If the ‘-p’ option is supplied, the
process or job identifier of the job for which the exit status is
returned is assigned to the variable VARNAME named by the option
argument. The variable will be unset initially, before any
- assignment. This is useful only when the '-n' option is supplied.
- Supplying the '-f' option, when job control is enabled, forces
- 'wait' to wait for each PID or JOBSPEC to terminate before
+ assignment. This is useful only when the ‘-n’ option is supplied.
+ Supplying the ‘-f’ option, when job control is enabled, forces
+ ‘wait’ to wait for each PID or JOBSPEC to terminate before
returning its status, instead of returning when it changes status.
If neither JOBSPEC nor PID specifies an active child process of the
- shell, the return status is 127. If 'wait' is interrupted by a
+ shell, the return status is 127. If ‘wait’ is interrupted by a
signal, the return status will be greater than 128, as described
above (*note Signals::). Otherwise, the return status is the exit
status of the last process or job waited for.
-'disown'
+‘disown’
disown [-ar] [-h] [JOBSPEC ... | PID ... ]
Without options, remove each JOBSPEC from the table of active jobs.
- If the '-h' option is given, the job is not removed from the table,
- but is marked so that 'SIGHUP' is not sent to the job if the shell
- receives a 'SIGHUP'. If JOBSPEC is not present, and neither the
- '-a' nor the '-r' option is supplied, the current job is used. If
- no JOBSPEC is supplied, the '-a' option means to remove or mark all
- jobs; the '-r' option without a JOBSPEC argument restricts
+ If the ‘-h’ option is given, the job is not removed from the table,
+ but is marked so that ‘SIGHUP’ is not sent to the job if the shell
+ receives a ‘SIGHUP’. If JOBSPEC is not present, and neither the
+ ‘-a’ nor the ‘-r’ option is supplied, the current job is used. If
+ no JOBSPEC is supplied, the ‘-a’ option means to remove or mark all
+ jobs; the ‘-r’ option without a JOBSPEC argument restricts
operation to running jobs.
-'suspend'
+‘suspend’
suspend [-f]
- Suspend the execution of this shell until it receives a 'SIGCONT'
+ Suspend the execution of this shell until it receives a ‘SIGCONT’
signal. A login shell, or a shell without job control enabled,
- cannot be suspended; the '-f' option can be used to override this
+ cannot be suspended; the ‘-f’ option can be used to override this
and force the suspension. The return status is 0 unless the shell
- is a login shell or job control is not enabled and '-f' is not
+ is a login shell or job control is not enabled and ‘-f’ is not
supplied.
- When job control is not active, the 'kill' and 'wait' builtins do not
+ When job control is not active, the ‘kill’ and ‘wait’ builtins do not
accept JOBSPEC arguments. They must be supplied process IDs.
\1f
7.3 Job Control Variables
=========================
-'auto_resume'
+‘auto_resume’
This variable controls how the shell interacts with the user and
job control. If this variable exists then single word simple
commands without redirections are treated as candidates for
there is more than one job beginning with the string typed, then
the most recently accessed job will be selected. The name of a
stopped job, in this context, is the command line used to start it.
- If this variable is set to the value 'exact', the string supplied
+ If this variable is set to the value ‘exact’, the string supplied
must match the name of a stopped job exactly; if set to
- 'substring', the string supplied needs to match a substring of the
- name of a stopped job. The 'substring' value provides
- functionality analogous to the '%?' job ID (*note Job Control
+ ‘substring’, the string supplied needs to match a substring of the
+ name of a stopped job. The ‘substring’ value provides
+ functionality analogous to the ‘%?’ job ID (*note Job Control
Basics::). If set to any other value, the supplied string must be
a prefix of a stopped job's name; this provides functionality
- analogous to the '%' job ID.
+ analogous to the ‘%’ job ID.
\1f
File: bash.info, Node: Command Line Editing, Next: Using History Interactively, Prev: Job Control, Up: Top
editing interface. Command line editing is provided by the Readline
library, which is used by several different programs, including Bash.
Command line editing is enabled by default when using an interactive
-shell, unless the '--noediting' option is supplied at shell invocation.
-Line editing is also used when using the '-e' option to the 'read'
+shell, unless the ‘--noediting’ option is supplied at shell invocation.
+Line editing is also used when using the ‘-e’ option to the ‘read’
builtin command (*note Bash Builtins::). By default, the line editing
commands are similar to those of Emacs. A vi-style line editing
interface is also available. Line editing can be enabled at any time
-using the '-o emacs' or '-o vi' options to the 'set' builtin command
-(*note The Set Builtin::), or disabled using the '+o emacs' or '+o vi'
-options to 'set'.
+using the ‘-o emacs’ or ‘-o vi’ options to the ‘set’ builtin command
+(*note The Set Builtin::), or disabled using the ‘+o emacs’ or ‘+o vi’
+options to ‘set’.
* Menu:
The following paragraphs describe the notation used to represent
keystrokes.
- The text 'C-k' is read as 'Control-K' and describes the character
+ The text ‘C-k’ is read as 'Control-K' and describes the character
produced when the <k> key is pressed while the Control key is depressed.
- The text 'M-k' is read as 'Meta-K' and describes the character
+ The text ‘M-k’ is read as 'Meta-K' and describes the character
produced when the Meta key (if you have one) is depressed, and the <k>
key is pressed. The Meta key is labeled <ALT> on many keyboards. On
keyboards with two keys labeled <ALT> (usually to either side of the
If you do not have a Meta or <ALT> key, or another key working as a
Meta key, the identical keystroke can be generated by typing <ESC>
-_first_, and then typing <k>. Either process is known as "metafying"
+_first_, and then typing <k>. Either process is known as “metafying”
the <k> key.
- The text 'M-C-k' is read as 'Meta-Control-k' and describes the
-character produced by "metafying" 'C-k'.
+ The text ‘M-C-k’ is read as 'Meta-Control-k' and describes the
+character produced by “metafying” ‘C-k’.
In addition, several keys have their own names. Specifically, <DEL>,
<ESC>, <LFD>, <SPC>, <RET>, and <TAB> all stand for themselves when seen
Sometimes you may mistype a character, and not notice the error until
you have typed several other characters. In that case, you can type
-'C-b' to move the cursor to the left, and then correct your mistake.
-Afterwards, you can move the cursor to the right with 'C-f'.
+‘C-b’ to move the cursor to the left, and then correct your mistake.
+Afterwards, you can move the cursor to the right with ‘C-f’.
When you add text in the middle of a line, you will notice that
characters to the right of the cursor are 'pushed over' to make room for
fill in the blank space created by the removal of the text. A list of
the bare essentials for editing the text of an input line follows.
-'C-b'
+‘C-b’
Move back one character.
-'C-f'
+‘C-f’
Move forward one character.
<DEL> or <Backspace>
Delete the character to the left of the cursor.
-'C-d'
+‘C-d’
Delete the character underneath the cursor.
Printing characters
Insert the character into the line at the cursor.
-'C-_' or 'C-x C-u'
+‘C-_’ or ‘C-x C-u’
Undo the last editing command. You can undo all the way back to an
empty line.
(Depending on your configuration, the <Backspace> key might be set to
delete the character to the left of the cursor and the <DEL> key set to
-delete the character underneath the cursor, like 'C-d', rather than the
+delete the character underneath the cursor, like ‘C-d’, rather than the
character to the left of the cursor.)
\1f
The above table describes the most basic keystrokes that you need in
order to do editing of the input line. For your convenience, many other
-commands have been added in addition to 'C-b', 'C-f', 'C-d', and <DEL>.
+commands have been added in addition to ‘C-b’, ‘C-f’, ‘C-d’, and <DEL>.
Here are some commands for moving more rapidly about the line.
-'C-a'
+‘C-a’
Move to the start of the line.
-'C-e'
+‘C-e’
Move to the end of the line.
-'M-f'
+‘M-f’
Move forward a word, where a word is composed of letters and
digits.
-'M-b'
+‘M-b’
Move backward a word.
-'C-l'
+‘C-l’
Clear the screen, reprinting the current line at the top.
- Notice how 'C-f' moves forward a character, while 'M-f' moves forward
+ Notice how ‘C-f’ moves forward a character, while ‘M-f’ moves forward
a word. It is a loose convention that control keystrokes operate on
characters while meta keystrokes operate on words.
8.2.3 Readline Killing Commands
-------------------------------
-"Killing" text means to delete the text from the line, but to save it
-away for later use, usually by "yanking" (re-inserting) it back into the
+“Killing” text means to delete the text from the line, but to save it
+away for later use, usually by “yanking” (re-inserting) it back into the
line. ('Cut' and 'paste' are more recent jargon for 'kill' and 'yank'.)
If the description for a command says that it 'kills' text, then you
can be sure that you can get the text back in a different (or the same)
place later.
- When you use a kill command, the text is saved in a "kill-ring". Any
+ When you use a kill command, the text is saved in a “kill-ring”. Any
number of consecutive kills save all of the killed text together, so
that when you yank it back, you get it all. The kill ring is not line
specific; the text that you killed on a previously typed line is
Here is the list of commands for killing text.
-'C-k'
+‘C-k’
Kill the text from the current cursor position to the end of the
line.
-'M-d'
+‘M-d’
Kill from the cursor to the end of the current word, or, if between
words, to the end of the next word. Word boundaries are the same
- as those used by 'M-f'.
+ as those used by ‘M-f’.
-'M-<DEL>'
+‘M-<DEL>’
Kill from the cursor to the start of the current word, or, if
between words, to the start of the previous word. Word boundaries
- are the same as those used by 'M-b'.
+ are the same as those used by ‘M-b’.
-'C-w'
+‘C-w’
Kill from the cursor to the previous whitespace. This is different
- than 'M-<DEL>' because the word boundaries differ.
+ than ‘M-<DEL>’ because the word boundaries differ.
- Here is how to "yank" the text back into the line. Yanking means to
+ Here is how to “yank” the text back into the line. Yanking means to
copy the most-recently-killed text from the kill buffer.
-'C-y'
+‘C-y’
Yank the most recently killed text back into the buffer at the
cursor.
-'M-y'
+‘M-y’
Rotate the kill-ring, and yank the new top. You can only do this
- if the prior command is 'C-y' or 'M-y'.
+ if the prior command is ‘C-y’ or ‘M-y’.
\1f
File: bash.info, Node: Readline Arguments, Next: Searching, Prev: Readline Killing Commands, Up: Readline Interaction
argument that is significant. If you pass a negative argument to a
command which normally acts in a forward direction, that command will
act in a backward direction. For example, to kill text back to the
-start of the line, you might type 'M-- C-k'.
+start of the line, you might type ‘M-- C-k’.
The general way to pass numeric arguments to a command is to type
meta digits before the command. If the first 'digit' typed is a minus
-sign ('-'), then the sign of the argument will be negative. Once you
+sign (‘-’), then the sign of the argument will be negative. Once you
have typed one meta digit to get the argument started, you can type the
remainder of the digits, and then the command. For example, to give the
-'C-d' command an argument of 10, you could type 'M-1 0 C-d', which will
+‘C-d’ command an argument of 10, you could type ‘M-1 0 C-d’, which will
delete the next ten characters on the input line.
\1f
Readline provides commands for searching through the command history
(*note Bash History Facilities::) for lines containing a specified
-string. There are two search modes: "incremental" and
-"non-incremental".
+string. There are two search modes: “incremental” and
+“non-incremental”.
Incremental searches begin before the user has finished typing the
search string. As each character of the search string is typed,
Readline displays the next entry from the history matching the string
typed so far. An incremental search requires only as many characters as
needed to find the desired history entry. To search backward in the
-history for a particular string, type 'C-r'. Typing 'C-s' searches
+history for a particular string, type ‘C-r’. Typing ‘C-s’ searches
forward through the history. The characters present in the value of the
-'isearch-terminators' variable are used to terminate an incremental
+‘isearch-terminators’ variable are used to terminate an incremental
search. If that variable has not been assigned a value, the <ESC> and
-'C-J' characters will terminate an incremental search. 'C-g' will abort
+‘C-J’ characters will terminate an incremental search. ‘C-g’ will abort
an incremental search and restore the original line. When the search is
terminated, the history entry containing the search string becomes the
current line.
- To find other matching entries in the history list, type 'C-r' or
-'C-s' as appropriate. This will search backward or forward in the
+ To find other matching entries in the history list, type ‘C-r’ or
+‘C-s’ as appropriate. This will search backward or forward in the
history for the next entry matching the search string typed so far. Any
other key sequence bound to a Readline command will terminate the search
and execute that command. For instance, a <RET> will terminate the
history list. A movement command will terminate the search, make the
last line found the current line, and begin editing.
- Readline remembers the last incremental search string. If two 'C-r's
+ Readline remembers the last incremental search string. If two ‘C-r’s
are typed without any intervening characters defining a new search
-string, any remembered search string is used.
+string, Readline uses any remembered search string.
Non-incremental searches read the entire search string before
starting to search for matching history lines. The search string may be
Although the Readline library comes with a set of Emacs-like keybindings
installed by default, it is possible to use a different set of
keybindings. Any user can customize programs that use Readline by
-putting commands in an "inputrc" file, conventionally in their home
+putting commands in an “inputrc” file, conventionally in their home
directory. The name of this file is taken from the value of the shell
-variable 'INPUTRC'. If that variable is unset, the default is
-'~/.inputrc'. If that file does not exist or cannot be read, the
-ultimate default is '/etc/inputrc'. The 'bind' builtin command can also
+variable ‘INPUTRC’. If that variable is unset, the default is
+‘~/.inputrc’. If that file does not exist or cannot be read, the
+ultimate default is ‘/etc/inputrc’. The ‘bind’ builtin command can also
be used to set Readline keybindings and variables. *Note Bash
Builtins::.
When a program which uses the Readline library starts up, the init
file is read, and the key bindings are set.
- In addition, the 'C-x C-r' command re-reads this init file, thus
+ In addition, the ‘C-x C-r’ command re-reads this init file, thus
incorporating any changes that you might have made to it.
* Menu:
-------------------------------
There are only a few basic constructs allowed in the Readline init file.
-Blank lines are ignored. Lines beginning with a '#' are comments.
-Lines beginning with a '$' indicate conditional constructs (*note
+Blank lines are ignored. Lines beginning with a ‘#’ are comments.
+Lines beginning with a ‘$’ indicate conditional constructs (*note
Conditional Init Constructs::). Other lines denote variable settings
and key bindings.
Variable Settings
You can modify the run-time behavior of Readline by altering the
- values of variables in Readline using the 'set' command within the
+ values of variables in Readline using the ‘set’ command within the
init file. The syntax is simple:
set VARIABLE VALUE
Here, for example, is how to change from the default Emacs-like key
- binding to use 'vi' line editing commands:
+ binding to use ‘vi’ line editing commands:
set editing-mode vi
on if the value is null or empty, ON (case-insensitive), or 1. Any
other value results in the variable being set to off.
- The 'bind -V' command lists the current Readline variable names and
+ The ‘bind -V’ command lists the current Readline variable names and
values. *Note Bash Builtins::.
A great deal of run-time behavior is changeable with the following
variables.
- 'active-region-start-color'
+ ‘active-region-start-color’
A string variable that controls the text color and background
when displaying the text in the active region (see the
- description of 'enable-active-region' below). This string
+ description of ‘enable-active-region’ below). This string
must not take up any physical character positions on the
display, so it should consist only of terminal escape
sequences. It is output to the terminal before displaying the
default value whenever the terminal type changes. The default
value is the string that puts the terminal in standout mode,
as obtained from the terminal's terminfo description. A
- sample value might be '\e[01;33m'.
+ sample value might be ‘\e[01;33m’.
- 'active-region-end-color'
+ ‘active-region-end-color’
A string variable that "undoes" the effects of
- 'active-region-start-color' and restores "normal" terminal
+ ‘active-region-start-color’ and restores "normal" terminal
display appearance after displaying text in the active region.
This string must not take up any physical character positions
on the display, so it should consist only of terminal escape
default value whenever the terminal type changes. The default
value is the string that restores the terminal from standout
mode, as obtained from the terminal's terminfo description. A
- sample value might be '\e[0m'.
+ sample value might be ‘\e[0m’.
- 'bell-style'
+ ‘bell-style’
Controls what happens when Readline wants to ring the terminal
- bell. If set to 'none', Readline never rings the bell. If
- set to 'visible', Readline uses a visible bell if one is
- available. If set to 'audible' (the default), Readline
+ bell. If set to ‘none’, Readline never rings the bell. If
+ set to ‘visible’, Readline uses a visible bell if one is
+ available. If set to ‘audible’ (the default), Readline
attempts to ring the terminal's bell.
- 'bind-tty-special-chars'
- If set to 'on' (the default), Readline attempts to bind the
+ ‘bind-tty-special-chars’
+ If set to ‘on’ (the default), Readline attempts to bind the
control characters that are treated specially by the kernel's
terminal driver to their Readline equivalents. These override
- the default Readline bindings described here. Type 'stty -a'
+ the default Readline bindings described here. Type ‘stty -a’
at a Bash prompt to see your current terminal settings,
- including the special control characters (usually 'cchars').
+ including the special control characters (usually ‘cchars’).
- 'blink-matching-paren'
- If set to 'on', Readline attempts to briefly move the cursor
+ ‘blink-matching-paren’
+ If set to ‘on’, Readline attempts to briefly move the cursor
to an opening parenthesis when a closing parenthesis is
- inserted. The default is 'off'.
+ inserted. The default is ‘off’.
- 'colored-completion-prefix'
- If set to 'on', when listing completions, Readline displays
+ ‘colored-completion-prefix’
+ If set to ‘on’, when listing completions, Readline displays
the common prefix of the set of possible completions using a
different color. The color definitions are taken from the
- value of the 'LS_COLORS' environment variable. If there is a
- color definition in 'LS_COLORS' for the custom suffix
- 'readline-colored-completion-prefix', Readline uses this color
+ value of the ‘LS_COLORS’ environment variable. If there is a
+ color definition in ‘LS_COLORS’ for the custom suffix
+ ‘readline-colored-completion-prefix’, Readline uses this color
for the common prefix instead of its default. The default is
- 'off'.
+ ‘off’.
- 'colored-stats'
- If set to 'on', Readline displays possible completions using
+ ‘colored-stats’
+ If set to ‘on’, Readline displays possible completions using
different colors to indicate their file type. The color
- definitions are taken from the value of the 'LS_COLORS'
- environment variable. The default is 'off'.
+ definitions are taken from the value of the ‘LS_COLORS’
+ environment variable. The default is ‘off’.
- 'comment-begin'
+ ‘comment-begin’
The string to insert at the beginning of the line when the
- 'insert-comment' command is executed. The default value is
- '"#"'.
+ ‘insert-comment’ command is executed. The default value is
+ ‘"#"’.
- 'completion-display-width'
+ ‘completion-display-width’
The number of screen columns used to display possible matches
when performing completion. The value is ignored if it is
less than 0 or greater than the terminal screen width. A
value of 0 will cause matches to be displayed one per line.
The default value is -1.
- 'completion-ignore-case'
- If set to 'on', Readline performs filename matching and
+ ‘completion-ignore-case’
+ If set to ‘on’, Readline performs filename matching and
completion in a case-insensitive fashion. The default value
- is 'off'.
+ is ‘off’.
- 'completion-map-case'
- If set to 'on', and COMPLETION-IGNORE-CASE is enabled,
- Readline treats hyphens ('-') and underscores ('_') as
+ ‘completion-map-case’
+ If set to ‘on’, and COMPLETION-IGNORE-CASE is enabled,
+ Readline treats hyphens (‘-’) and underscores (‘_’) as
equivalent when performing case-insensitive filename matching
- and completion. The default value is 'off'.
+ and completion. The default value is ‘off’.
- 'completion-prefix-display-length'
+ ‘completion-prefix-display-length’
The length in characters of the common prefix of a list of
possible completions that is displayed without modification.
When set to a value greater than zero, common prefixes longer
than this value are replaced with an ellipsis when displaying
possible completions.
- 'completion-query-items'
+ ‘completion-query-items’
The number of possible completions that determines when the
user is asked whether the list of possibilities should be
displayed. If the number of possible completions is greater
listed. This variable must be set to an integer value greater
than or equal to zero. A zero value means Readline should
never ask; negative values are treated as zero. The default
- limit is '100'.
+ limit is ‘100’.
- 'convert-meta'
- If set to 'on', Readline will convert characters with the
+ ‘convert-meta’
+ If set to ‘on’, Readline will convert characters with the
eighth bit set to an ASCII key sequence by stripping the
eighth bit and prefixing an <ESC> character, converting them
- to a meta-prefixed key sequence. The default value is 'on',
- but will be set to 'off' if the locale is one that contains
+ to a meta-prefixed key sequence. The default value is ‘on’,
+ but will be set to ‘off’ if the locale is one that contains
eight-bit characters. This variable is dependent on the
- 'LC_CTYPE' locale category, and may change if the locale is
+ ‘LC_CTYPE’ locale category, and may change if the locale is
changed.
- 'disable-completion'
- If set to 'On', Readline will inhibit word completion.
+ ‘disable-completion’
+ If set to ‘On’, Readline will inhibit word completion.
Completion characters will be inserted into the line as if
- they had been mapped to 'self-insert'. The default is 'off'.
+ they had been mapped to ‘self-insert’. The default is ‘off’.
- 'echo-control-characters'
- When set to 'on', on operating systems that indicate they
+ ‘echo-control-characters’
+ When set to ‘on’, on operating systems that indicate they
support it, Readline echoes a character corresponding to a
- signal generated from the keyboard. The default is 'on'.
+ signal generated from the keyboard. The default is ‘on’.
- 'editing-mode'
- The 'editing-mode' variable controls which default set of key
+ ‘editing-mode’
+ The ‘editing-mode’ variable controls which default set of key
bindings is used. By default, Readline starts up in Emacs
editing mode, where the keystrokes are most similar to Emacs.
- This variable can be set to either 'emacs' or 'vi'.
+ This variable can be set to either ‘emacs’ or ‘vi’.
- 'emacs-mode-string'
+ ‘emacs-mode-string’
If the SHOW-MODE-IN-PROMPT variable is enabled, this string is
displayed immediately before the last line of the primary
prompt when emacs editing mode is active. The value is
expanded like a key binding, so the standard set of meta- and
control prefixes and backslash escape sequences is available.
- Use the '\1' and '\2' escapes to begin and end sequences of
+ Use the ‘\1’ and ‘\2’ escapes to begin and end sequences of
non-printing characters, which can be used to embed a terminal
- control sequence into the mode string. The default is '@'.
+ control sequence into the mode string. The default is ‘@’.
- 'enable-active-region'
- The "point" is the current cursor position, and "mark" refers
+ ‘enable-active-region’
+ The “point” is the current cursor position, and “mark” refers
to a saved cursor position (*note Commands For Moving::). The
text between the point and mark is referred to as the
- "region". When this variable is set to 'On', Readline allows
- certain commands to designate the region as "active". When
+ “region”. When this variable is set to ‘On’, Readline allows
+ certain commands to designate the region as “active”. When
the region is active, Readline highlights the text in the
- region using the value of the 'active-region-start-color',
+ region using the value of the ‘active-region-start-color’,
which defaults to the string that enables the terminal's
standout mode. The active region shows the text inserted by
bracketed-paste and any matching text found by incremental and
- non-incremental history searches. The default is 'On'.
+ non-incremental history searches. The default is ‘On’.
- 'enable-bracketed-paste'
- When set to 'On', Readline configures the terminal to insert
+ ‘enable-bracketed-paste’
+ When set to ‘On’, Readline configures the terminal to insert
each paste into the editing buffer as a single string of
characters, instead of treating each character as if it had
been read from the keyboard. This is called putting the
- terminal into "bracketed paste mode"; it prevents Readline
+ terminal into “bracketed paste mode”; it prevents Readline
from executing any editing commands bound to key sequences
- appearing in the pasted text. The default is 'On'.
+ appearing in the pasted text. The default is ‘On’.
- 'enable-keypad'
- When set to 'on', Readline will try to enable the application
+ ‘enable-keypad’
+ When set to ‘on’, Readline will try to enable the application
keypad when it is called. Some systems need this to enable
- the arrow keys. The default is 'off'.
+ the arrow keys. The default is ‘off’.
- 'enable-meta-key'
- When set to 'on', Readline will try to enable any meta
+ ‘enable-meta-key’
+ When set to ‘on’, Readline will try to enable any meta
modifier key the terminal claims to support when it is called.
On many terminals, the meta key is used to send eight-bit
- characters. The default is 'on'.
+ characters. The default is ‘on’.
- 'expand-tilde'
- If set to 'on', tilde expansion is performed when Readline
- attempts word completion. The default is 'off'.
+ ‘expand-tilde’
+ If set to ‘on’, tilde expansion is performed when Readline
+ attempts word completion. The default is ‘off’.
- 'history-preserve-point'
- If set to 'on', the history code attempts to place the point
+ ‘history-preserve-point’
+ If set to ‘on’, the history code attempts to place the point
(the current cursor position) at the same location on each
- history line retrieved with 'previous-history' or
- 'next-history'. The default is 'off'.
+ history line retrieved with ‘previous-history’ or
+ ‘next-history’. The default is ‘off’.
- 'history-size'
+ ‘history-size’
Set the maximum number of history entries saved in the history
list. If set to zero, any existing history entries are
deleted and no new entries are saved. If set to a value less
attempt is made to set HISTORY-SIZE to a non-numeric value,
the maximum number of history entries will be set to 500.
- 'horizontal-scroll-mode'
- This variable can be set to either 'on' or 'off'. Setting it
- to 'on' means that the text of the lines being edited will
+ ‘horizontal-scroll-mode’
+ This variable can be set to either ‘on’ or ‘off’. Setting it
+ to ‘on’ means that the text of the lines being edited will
scroll horizontally on a single screen line when they are
longer than the width of the screen, instead of wrapping onto
- a new screen line. This variable is automatically set to 'on'
+ a new screen line. This variable is automatically set to ‘on’
for terminals of height 1. By default, this variable is set
- to 'off'.
+ to ‘off’.
- 'input-meta'
- If set to 'on', Readline will enable eight-bit input (it will
+ ‘input-meta’
+ If set to ‘on’, Readline will enable eight-bit input (it will
not clear the eighth bit in the characters it reads),
regardless of what the terminal claims it can support. The
- default value is 'off', but Readline will set it to 'on' if
+ default value is ‘off’, but Readline will set it to ‘on’ if
the locale contains eight-bit characters. The name
- 'meta-flag' is a synonym for this variable. This variable is
- dependent on the 'LC_CTYPE' locale category, and may change if
+ ‘meta-flag’ is a synonym for this variable. This variable is
+ dependent on the ‘LC_CTYPE’ locale category, and may change if
the locale is changed.
- 'isearch-terminators'
+ ‘isearch-terminators’
The string of characters that should terminate an incremental
search without subsequently executing the character as a
command (*note Searching::). If this variable has not been
- given a value, the characters <ESC> and 'C-J' will terminate
+ given a value, the characters <ESC> and ‘C-J’ will terminate
an incremental search.
- 'keymap'
+ ‘keymap’
Sets Readline's idea of the current keymap for key binding
- commands. Built-in 'keymap' names are 'emacs',
- 'emacs-standard', 'emacs-meta', 'emacs-ctlx', 'vi', 'vi-move',
- 'vi-command', and 'vi-insert'. 'vi' is equivalent to
- 'vi-command' ('vi-move' is also a synonym); 'emacs' is
- equivalent to 'emacs-standard'. Applications may add
- additional names. The default value is 'emacs'. The value of
- the 'editing-mode' variable also affects the default keymap.
-
- 'keyseq-timeout'
+ commands. Built-in ‘keymap’ names are ‘emacs’,
+ ‘emacs-standard’, ‘emacs-meta’, ‘emacs-ctlx’, ‘vi’, ‘vi-move’,
+ ‘vi-command’, and ‘vi-insert’. ‘vi’ is equivalent to
+ ‘vi-command’ (‘vi-move’ is also a synonym); ‘emacs’ is
+ equivalent to ‘emacs-standard’. Applications may add
+ additional names. The default value is ‘emacs’. The value of
+ the ‘editing-mode’ variable also affects the default keymap.
+
+ ‘keyseq-timeout’
Specifies the duration Readline will wait for a character when
reading an ambiguous key sequence (one that can form a
complete key sequence using the input read so far, or can take
input is received within the timeout, Readline will use the
shorter but complete key sequence. Readline uses this value
to determine whether or not input is available on the current
- input source ('rl_instream' by default). The value is
+ input source (‘rl_instream’ by default). The value is
specified in milliseconds, so a value of 1000 means that
Readline will wait one second for additional input. If this
variable is set to a value less than or equal to zero, or to a
non-numeric value, Readline will wait until another key is
pressed to decide which key sequence to complete. The default
- value is '500'.
+ value is ‘500’.
- 'mark-directories'
- If set to 'on', completed directory names have a slash
- appended. The default is 'on'.
+ ‘mark-directories’
+ If set to ‘on’, completed directory names have a slash
+ appended. The default is ‘on’.
- 'mark-modified-lines'
- This variable, when set to 'on', causes Readline to display an
- asterisk ('*') at the start of history lines which have been
- modified. This variable is 'off' by default.
+ ‘mark-modified-lines’
+ This variable, when set to ‘on’, causes Readline to display an
+ asterisk (‘*’) at the start of history lines which have been
+ modified. This variable is ‘off’ by default.
- 'mark-symlinked-directories'
- If set to 'on', completed names which are symbolic links to
+ ‘mark-symlinked-directories’
+ If set to ‘on’, completed names which are symbolic links to
directories have a slash appended (subject to the value of
- 'mark-directories'). The default is 'off'.
+ ‘mark-directories’). The default is ‘off’.
- 'match-hidden-files'
- This variable, when set to 'on', causes Readline to match
- files whose names begin with a '.' (hidden files) when
- performing filename completion. If set to 'off', the leading
- '.' must be supplied by the user in the filename to be
- completed. This variable is 'on' by default.
+ ‘match-hidden-files’
+ This variable, when set to ‘on’, forces Readline to match
+ files whose names begin with a ‘.’ (hidden files) when
+ performing filename completion. If set to ‘off’, the user
+ must include the leading ‘.’ in the filename to be completed.
+ This variable is ‘on’ by default.
- 'menu-complete-display-prefix'
- If set to 'on', menu completion displays the common prefix of
+ ‘menu-complete-display-prefix’
+ If set to ‘on’, menu completion displays the common prefix of
the list of possible completions (which may be empty) before
- cycling through the list. The default is 'off'.
+ cycling through the list. The default is ‘off’.
- 'output-meta'
- If set to 'on', Readline will display characters with the
+ ‘output-meta’
+ If set to ‘on’, Readline will display characters with the
eighth bit set directly rather than as a meta-prefixed escape
- sequence. The default is 'off', but Readline will set it to
- 'on' if the locale contains eight-bit characters. This
- variable is dependent on the 'LC_CTYPE' locale category, and
+ sequence. The default is ‘off’, but Readline will set it to
+ ‘on’ if the locale contains eight-bit characters. This
+ variable is dependent on the ‘LC_CTYPE’ locale category, and
may change if the locale is changed.
- 'page-completions'
- If set to 'on', Readline uses an internal 'more'-like pager to
+ ‘page-completions’
+ If set to ‘on’, Readline uses an internal ‘more’-like pager to
display a screenful of possible completions at a time. This
- variable is 'on' by default.
+ variable is ‘on’ by default.
- 'print-completions-horizontally'
- If set to 'on', Readline will display completions with matches
+ ‘print-completions-horizontally’
+ If set to ‘on’, Readline will display completions with matches
sorted horizontally in alphabetical order, rather than down
- the screen. The default is 'off'.
+ the screen. The default is ‘off’.
- 'revert-all-at-newline'
- If set to 'on', Readline will undo all changes to history
- lines before returning when 'accept-line' is executed. By
+ ‘revert-all-at-newline’
+ If set to ‘on’, Readline will undo all changes to history
+ lines before returning when ‘accept-line’ is executed. By
default, history lines may be modified and retain individual
- undo lists across calls to 'readline()'. The default is
- 'off'.
+ undo lists across calls to ‘readline()’. The default is
+ ‘off’.
- 'search-ignore-case'
- If set to 'on', Readline performs incremental and
+ ‘search-ignore-case’
+ If set to ‘on’, Readline performs incremental and
non-incremental history list searches in a case-insensitive
- fashion. The default value is 'off'.
+ fashion. The default value is ‘off’.
- 'show-all-if-ambiguous'
+ ‘show-all-if-ambiguous’
This alters the default behavior of the completion functions.
- If set to 'on', words which have more than one possible
+ If set to ‘on’, words which have more than one possible
completion cause the matches to be listed immediately instead
- of ringing the bell. The default value is 'off'.
+ of ringing the bell. The default value is ‘off’.
- 'show-all-if-unmodified'
+ ‘show-all-if-unmodified’
This alters the default behavior of the completion functions
in a fashion similar to SHOW-ALL-IF-AMBIGUOUS. If set to
- 'on', words which have more than one possible completion
+ ‘on’, words which have more than one possible completion
without any possible partial completion (the possible
completions don't share a common prefix) cause the matches to
be listed immediately instead of ringing the bell. The
- default value is 'off'.
+ default value is ‘off’.
- 'show-mode-in-prompt'
- If set to 'on', add a string to the beginning of the prompt
+ ‘show-mode-in-prompt’
+ If set to ‘on’, add a string to the beginning of the prompt
indicating the editing mode: emacs, vi command, or vi
insertion. The mode strings are user-settable (e.g.,
- EMACS-MODE-STRING). The default value is 'off'.
+ EMACS-MODE-STRING). The default value is ‘off’.
- 'skip-completed-text'
- If set to 'on', this alters the default completion behavior
+ ‘skip-completed-text’
+ If set to ‘on’, this alters the default completion behavior
when inserting a single match into the line. It's only active
when performing completion in the middle of a word. If
enabled, Readline does not insert characters from the
completion that match characters after point in the word being
completed, so portions of the word following the cursor are
not duplicated. For instance, if this is enabled, attempting
- completion when the cursor is after the 'e' in 'Makefile' will
- result in 'Makefile' rather than 'Makefilefile', assuming
+ completion when the cursor is after the ‘e’ in ‘Makefile’ will
+ result in ‘Makefile’ rather than ‘Makefilefile’, assuming
there is a single possible completion. The default value is
- 'off'.
+ ‘off’.
- 'vi-cmd-mode-string'
+ ‘vi-cmd-mode-string’
If the SHOW-MODE-IN-PROMPT variable is enabled, this string is
displayed immediately before the last line of the primary
prompt when vi editing mode is active and in command mode.
The value is expanded like a key binding, so the standard set
of meta- and control prefixes and backslash escape sequences
- is available. Use the '\1' and '\2' escapes to begin and end
+ is available. Use the ‘\1’ and ‘\2’ escapes to begin and end
sequences of non-printing characters, which can be used to
embed a terminal control sequence into the mode string. The
- default is '(cmd)'.
+ default is ‘(cmd)’.
- 'vi-ins-mode-string'
+ ‘vi-ins-mode-string’
If the SHOW-MODE-IN-PROMPT variable is enabled, this string is
displayed immediately before the last line of the primary
prompt when vi editing mode is active and in insertion mode.
The value is expanded like a key binding, so the standard set
of meta- and control prefixes and backslash escape sequences
- is available. Use the '\1' and '\2' escapes to begin and end
+ is available. Use the ‘\1’ and ‘\2’ escapes to begin and end
sequences of non-printing characters, which can be used to
embed a terminal control sequence into the mode string. The
- default is '(ins)'.
+ default is ‘(ins)’.
- 'visible-stats'
- If set to 'on', a character denoting a file's type is appended
+ ‘visible-stats’
+ If set to ‘on’, a character denoting a file's type is appended
to the filename when listing possible completions. The
- default is 'off'.
+ default is ‘off’.
Key Bindings
The syntax for controlling key bindings in the init file is simple.
In addition to command names, Readline allows keys to be bound to a
string that is inserted when the key is pressed (a MACRO).
- The 'bind -p' command displays Readline function names and bindings
+ The ‘bind -p’ command displays Readline function names and bindings
in a format that can be put directly into an initialization file.
*Note Bash Builtins::.
Meta-Rubout: backward-kill-word
Control-o: "> output"
- In the example above, 'C-u' is bound to the function
- 'universal-argument', 'M-DEL' is bound to the function
- 'backward-kill-word', and 'C-o' is bound to run the macro
+ In the example above, ‘C-u’ is bound to the function
+ ‘universal-argument’, ‘M-DEL’ is bound to the function
+ ‘backward-kill-word’, and ‘C-o’ is bound to run the macro
expressed on the right hand side (that is, to insert the text
- '> output' into the line).
+ ‘> output’ into the line).
A number of symbolic character names are recognized while
processing this key binding syntax: DEL, ESC, ESCAPE, LFD,
"\C-x\C-r": re-read-init-file
"\e[11~": "Function Key 1"
- In the above example, 'C-u' is again bound to the function
- 'universal-argument' (just as it was in the first example),
- ''C-x' 'C-r'' is bound to the function 're-read-init-file',
- and '<ESC> <[> <1> <1> <~>' is bound to insert the text
- 'Function Key 1'.
+ In the above example, ‘C-u’ is again bound to the function
+ ‘universal-argument’ (just as it was in the first example),
+ ‘‘C-x’ ‘C-r’’ is bound to the function ‘re-read-init-file’,
+ and ‘<ESC> <[> <1> <1> <~>’ is bound to insert the text
+ ‘Function Key 1’.
The following GNU Emacs style escape sequences are available when
specifying key sequences:
- '\C-'
+ ‘\C-’
control prefix
- '\M-'
+ ‘\M-’
meta prefix
- '\e'
+ ‘\e’
an escape character
- '\\'
+ ‘\\’
backslash
- '\"'
+ ‘\"’
<">, a double quotation mark
- '\''
+ ‘\'’
<'>, a single quote or apostrophe
In addition to the GNU Emacs style escape sequences, a second set
of backslash escapes is available:
- '\a'
+ ‘\a’
alert (bell)
- '\b'
+ ‘\b’
backspace
- '\d'
+ ‘\d’
delete
- '\f'
+ ‘\f’
form feed
- '\n'
+ ‘\n’
newline
- '\r'
+ ‘\r’
carriage return
- '\t'
+ ‘\t’
horizontal tab
- '\v'
+ ‘\v’
vertical tab
- '\NNN'
+ ‘\NNN’
the eight-bit character whose value is the octal value NNN
(one to three digits)
- '\xHH'
+ ‘\xHH’
the eight-bit character whose value is the hexadecimal value
HH (one or two hex digits)
used to indicate a macro definition. Unquoted text is assumed to
be a function name. In the macro body, the backslash escapes
described above are expanded. Backslash will quote any other
- character in the macro text, including '"' and '''. For example,
- the following binding will make ''C-x' \' insert a single '\' into
+ character in the macro text, including ‘"’ and ‘'’. For example,
+ the following binding will make ‘‘C-x’ \’ insert a single ‘\’ into
the line:
"\C-x\\": "\\"
variable settings to be performed as the result of tests. There are
four parser directives used.
-'$if'
- The '$if' construct allows bindings to be made based on the editing
+‘$if’
+ The ‘$if’ construct allows bindings to be made based on the editing
mode, the terminal being used, or the application using Readline.
The text of the test, after any comparison operator, extends to the
end of the line; unless otherwise noted, no characters are required
to isolate it.
- 'mode'
- The 'mode=' form of the '$if' directive is used to test
- whether Readline is in 'emacs' or 'vi' mode. This may be used
- in conjunction with the 'set keymap' command, for instance, to
- set bindings in the 'emacs-standard' and 'emacs-ctlx' keymaps
- only if Readline is starting out in 'emacs' mode.
+ ‘mode’
+ The ‘mode=’ form of the ‘$if’ directive is used to test
+ whether Readline is in ‘emacs’ or ‘vi’ mode. This may be used
+ in conjunction with the ‘set keymap’ command, for instance, to
+ set bindings in the ‘emacs-standard’ and ‘emacs-ctlx’ keymaps
+ only if Readline is starting out in ‘emacs’ mode.
- 'term'
- The 'term=' form may be used to include terminal-specific key
+ ‘term’
+ The ‘term=’ form may be used to include terminal-specific key
bindings, perhaps to bind the key sequences output by the
terminal's function keys. The word on the right side of the
- '=' is tested against both the full name of the terminal and
- the portion of the terminal name before the first '-'. This
- allows 'sun' to match both 'sun' and 'sun-cmd', for instance.
+ ‘=’ is tested against both the full name of the terminal and
+ the portion of the terminal name before the first ‘-’. This
+ allows ‘sun’ to match both ‘sun’ and ‘sun-cmd’, for instance.
- 'version'
- The 'version' test may be used to perform comparisons against
- specific Readline versions. The 'version' expands to the
+ ‘version’
+ The ‘version’ test may be used to perform comparisons against
+ specific Readline versions. The ‘version’ expands to the
current Readline version. The set of comparison operators
- includes '=' (and '=='), '!=', '<=', '>=', '<', and '>'. The
+ includes ‘=’ (and ‘==’), ‘!=’, ‘<=’, ‘>=’, ‘<’, and ‘>’. The
version number supplied on the right side of the operator
consists of a major version number, an optional decimal point,
- and an optional minor version (e.g., '7.1'). If the minor
- version is omitted, it is assumed to be '0'. The operator may
- be separated from the string 'version' and from the version
+ and an optional minor version (e.g., ‘7.1’). If the minor
+ version is omitted, it is assumed to be ‘0’. The operator may
+ be separated from the string ‘version’ and from the version
number argument by whitespace. The following example sets a
variable if the Readline version being used is 7.0 or newer:
$if version >= 7.0
set show-mode-in-prompt on
$endif
- 'application'
+ ‘application’
The APPLICATION construct is used to include
application-specific settings. Each program using the
Readline library sets the APPLICATION NAME, and you can test
"\C-xq": "\eb\"\ef\""
$endif
- 'variable'
+ ‘variable’
The VARIABLE construct provides simple equality tests for
Readline variables and values. The permitted comparison
- operators are '=', '==', and '!='. The variable name must be
+ operators are ‘=’, ‘==’, and ‘!=’. The variable name must be
separated from the comparison operator by whitespace; the
operator may be separated from the value on the right hand
side by whitespace. Both string and boolean variables may be
tested. Boolean variables must be tested against the values
ON and OFF. The following example is equivalent to the
- 'mode=emacs' test described above:
+ ‘mode=emacs’ test described above:
$if editing-mode == emacs
set show-mode-in-prompt on
$endif
-'$endif'
- This command, as seen in the previous example, terminates an '$if'
+‘$endif’
+ This command, as seen in the previous example, terminates an ‘$if’
command.
-'$else'
- Commands in this branch of the '$if' directive are executed if the
+‘$else’
+ Commands in this branch of the ‘$if’ directive are executed if the
test fails.
-'$include'
+‘$include’
This directive takes a single filename as an argument and reads
commands and bindings from that file. For example, the following
- directive reads from '/etc/inputrc':
+ directive reads from ‘/etc/inputrc’:
$include /etc/inputrc
\1f
* Miscellaneous Commands:: Other miscellaneous commands.
This section describes Readline commands that may be bound to key
-sequences. You can list your key bindings by executing 'bind -P' or,
-for a more terse format, suitable for an INPUTRC file, 'bind -p'.
+sequences. You can list your key bindings by executing ‘bind -P’ or,
+for a more terse format, suitable for an INPUTRC file, ‘bind -p’.
(*Note Bash Builtins::.) Command names without an accompanying key
sequence are unbound by default.
- In the following descriptions, "point" refers to the current cursor
-position, and "mark" refers to a cursor position saved by the 'set-mark'
+ In the following descriptions, “point” refers to the current cursor
+position, and “mark” refers to a cursor position saved by the ‘set-mark’
command. The text between the point and mark is referred to as the
-"region".
+“region”.
\1f
File: bash.info, Node: Commands For Moving, Next: Commands For History, Up: Bindable Readline Commands
8.4.1 Commands For Moving
-------------------------
-'beginning-of-line (C-a)'
+‘beginning-of-line (C-a)’
Move to the start of the current line.
-'end-of-line (C-e)'
+‘end-of-line (C-e)’
Move to the end of the line.
-'forward-char (C-f)'
+‘forward-char (C-f)’
Move forward a character.
-'backward-char (C-b)'
+‘backward-char (C-b)’
Move back a character.
-'forward-word (M-f)'
+‘forward-word (M-f)’
Move forward to the end of the next word. Words are composed of
letters and digits.
-'backward-word (M-b)'
+‘backward-word (M-b)’
Move back to the start of the current or previous word. Words are
composed of letters and digits.
-'shell-forward-word (M-C-f)'
+‘shell-forward-word (M-C-f)’
Move forward to the end of the next word. Words are delimited by
non-quoted shell metacharacters.
-'shell-backward-word (M-C-b)'
+‘shell-backward-word (M-C-b)’
Move back to the start of the current or previous word. Words are
delimited by non-quoted shell metacharacters.
-'previous-screen-line ()'
+‘previous-screen-line ()’
Attempt to move point to the same physical screen column on the
previous physical screen line. This will not have the desired
effect if the current Readline line does not take up more than one
physical line or if point is not greater than the length of the
prompt plus the screen width.
-'next-screen-line ()'
+‘next-screen-line ()’
Attempt to move point to the same physical screen column on the
next physical screen line. This will not have the desired effect
if the current Readline line does not take up more than one
physical line or if the length of the current Readline line is not
greater than the length of the prompt plus the screen width.
-'clear-display (M-C-l)'
+‘clear-display (M-C-l)’
Clear the screen and, if possible, the terminal's scrollback
buffer, then redraw the current line, leaving the current line at
the top of the screen.
-'clear-screen (C-l)'
+‘clear-screen (C-l)’
Clear the screen, then redraw the current line, leaving the current
line at the top of the screen.
-'redraw-current-line ()'
+‘redraw-current-line ()’
Refresh the current line. By default, this is unbound.
\1f
8.4.2 Commands For Manipulating The History
-------------------------------------------
-'accept-line (Newline or Return)'
+‘accept-line (Newline or Return)’
Accept the line regardless of where the cursor is. If this line is
non-empty, add it to the history list according to the setting of
- the 'HISTCONTROL' and 'HISTIGNORE' variables. If this line is a
+ the ‘HISTCONTROL’ and ‘HISTIGNORE’ variables. If this line is a
modified history line, then restore the history line to its
original state.
-'previous-history (C-p)'
+‘previous-history (C-p)’
Move 'back' through the history list, fetching the previous
command.
-'next-history (C-n)'
+‘next-history (C-n)’
Move 'forward' through the history list, fetching the next command.
-'beginning-of-history (M-<)'
+‘beginning-of-history (M-<)’
Move to the first line in the history.
-'end-of-history (M->)'
+‘end-of-history (M->)’
Move to the end of the input history, i.e., the line currently
being entered.
-'reverse-search-history (C-r)'
+‘reverse-search-history (C-r)’
Search backward starting at the current line and moving 'up'
through the history as necessary. This is an incremental search.
This command sets the region to the matched text and activates the
mark.
-'forward-search-history (C-s)'
+‘forward-search-history (C-s)’
Search forward starting at the current line and moving 'down'
through the history as necessary. This is an incremental search.
This command sets the region to the matched text and activates the
mark.
-'non-incremental-reverse-search-history (M-p)'
+‘non-incremental-reverse-search-history (M-p)’
Search backward starting at the current line and moving 'up'
through the history as necessary using a non-incremental search for
a string supplied by the user. The search string may match
anywhere in a history line.
-'non-incremental-forward-search-history (M-n)'
+‘non-incremental-forward-search-history (M-n)’
Search forward starting at the current line and moving 'down'
through the history as necessary using a non-incremental search for
a string supplied by the user. The search string may match
anywhere in a history line.
-'history-search-forward ()'
+‘history-search-forward ()’
Search forward through the history for the string of characters
between the start of the current line and the point. The search
string must match at the beginning of a history line. This is a
non-incremental search. By default, this command is unbound.
-'history-search-backward ()'
+‘history-search-backward ()’
Search backward through the history for the string of characters
between the start of the current line and the point. The search
string must match at the beginning of a history line. This is a
non-incremental search. By default, this command is unbound.
-'history-substring-search-forward ()'
+‘history-substring-search-forward ()’
Search forward through the history for the string of characters
between the start of the current line and the point. The search
string may match anywhere in a history line. This is a
non-incremental search. By default, this command is unbound.
-'history-substring-search-backward ()'
+‘history-substring-search-backward ()’
Search backward through the history for the string of characters
between the start of the current line and the point. The search
string may match anywhere in a history line. This is a
non-incremental search. By default, this command is unbound.
-'yank-nth-arg (M-C-y)'
+‘yank-nth-arg (M-C-y)’
Insert the first argument to the previous command (usually the
second word on the previous line) at point. With an argument N,
insert the Nth word from the previous command (the words in the
previous command begin with word 0). A negative argument inserts
the Nth word from the end of the previous command. Once the
- argument N is computed, the argument is extracted as if the '!N'
+ argument N is computed, the argument is extracted as if the ‘!N’
history expansion had been specified.
-'yank-last-arg (M-. or M-_)'
+‘yank-last-arg (M-. or M-_)’
Insert last argument to the previous command (the last word of the
previous history entry). With a numeric argument, behave exactly
- like 'yank-nth-arg'. Successive calls to 'yank-last-arg' move back
+ like ‘yank-nth-arg’. Successive calls to ‘yank-last-arg’ move back
through the history list, inserting the last word (or the word
specified by the argument to the first call) of each line in turn.
Any numeric argument supplied to these successive calls determines
the direction to move through the history. A negative argument
switches the direction through the history (back or forward). The
history expansion facilities are used to extract the last argument,
- as if the '!$' history expansion had been specified.
+ as if the ‘!$’ history expansion had been specified.
-'operate-and-get-next (C-o)'
+‘operate-and-get-next (C-o)’
Accept the current line for return to the calling application as if
a newline had been entered, and fetch the next line relative to the
current line from the history for editing. A numeric argument, if
supplied, specifies the history entry to use instead of the current
line.
-'fetch-history ()'
+‘fetch-history ()’
With a numeric argument, fetch that entry from the history list and
make it the current line. Without an argument, move back to the
first entry in the history list.
8.4.3 Commands For Changing Text
--------------------------------
-'end-of-file (usually C-d)'
+‘end-of-file (usually C-d)’
The character indicating end-of-file as set, for example, by
- 'stty'. If this character is read when there are no characters on
+ ‘stty’. If this character is read when there are no characters on
the line, and point is at the beginning of the line, Readline
interprets it as the end of input and returns EOF.
-'delete-char (C-d)'
+‘delete-char (C-d)’
Delete the character at point. If this function is bound to the
- same character as the tty EOF character, as 'C-d' commonly is, see
+ same character as the tty EOF character, as ‘C-d’ commonly is, see
above for the effects.
-'backward-delete-char (Rubout)'
+‘backward-delete-char (Rubout)’
Delete the character behind the cursor. A numeric argument means
to kill the characters instead of deleting them.
-'forward-backward-delete-char ()'
+‘forward-backward-delete-char ()’
Delete the character under the cursor, unless the cursor is at the
end of the line, in which case the character behind the cursor is
deleted. By default, this is not bound to a key.
-'quoted-insert (C-q or C-v)'
+‘quoted-insert (C-q or C-v)’
Add the next character typed to the line verbatim. This is how to
- insert key sequences like 'C-q', for example.
+ insert key sequences like ‘C-q’, for example.
-'self-insert (a, b, A, 1, !, ...)'
+‘self-insert (a, b, A, 1, !, ...)’
Insert yourself.
-'bracketed-paste-begin ()'
+‘bracketed-paste-begin ()’
This function is intended to be bound to the "bracketed paste"
escape sequence sent by some terminals, and such a binding is
assigned by default. It allows Readline to insert the pasted text
as a single unit without treating each character as if it had been
read from the keyboard. The characters are inserted as if each one
- was bound to 'self-insert' instead of executing any editing
+ was bound to ‘self-insert’ instead of executing any editing
commands.
Bracketed paste sets the region (the characters between point and
mark_: when the mark is active, Readline redisplay uses the
terminal's standout mode to denote the region.
-'transpose-chars (C-t)'
+‘transpose-chars (C-t)’
Drag the character before the cursor forward over the character at
the cursor, moving the cursor forward as well. If the insertion
point is at the end of the line, then this transposes the last two
characters of the line. Negative arguments have no effect.
-'transpose-words (M-t)'
+‘transpose-words (M-t)’
Drag the word before point past the word after point, moving point
past that word as well. If the insertion point is at the end of
the line, this transposes the last two words on the line.
-'shell-transpose-words (M-C-t)'
+‘shell-transpose-words (M-C-t)’
Drag the word before point past the word after point, moving point
past that word as well. If the insertion point is at the end of
the line, this transposes the last two words on the line. Word
- boundaries are the same as 'shell-forward-word' and
- 'shell-backward-word'.
+ boundaries are the same as ‘shell-forward-word’ and
+ ‘shell-backward-word’.
-'upcase-word (M-u)'
+‘upcase-word (M-u)’
Uppercase the current (or following) word. With a negative
argument, uppercase the previous word, but do not move the cursor.
-'downcase-word (M-l)'
+‘downcase-word (M-l)’
Lowercase the current (or following) word. With a negative
argument, lowercase the previous word, but do not move the cursor.
-'capitalize-word (M-c)'
+‘capitalize-word (M-c)’
Capitalize the current (or following) word. With a negative
argument, capitalize the previous word, but do not move the cursor.
-'overwrite-mode ()'
+‘overwrite-mode ()’
Toggle overwrite mode. With an explicit positive numeric argument,
switches to overwrite mode. With an explicit non-positive numeric
argument, switches to insert mode. This command affects only
- 'emacs' mode; 'vi' mode does overwrite differently. Each call to
- 'readline()' starts in insert mode.
+ ‘emacs’ mode; ‘vi’ mode does overwrite differently. Each call to
+ ‘readline()’ starts in insert mode.
- In overwrite mode, characters bound to 'self-insert' replace the
+ In overwrite mode, characters bound to ‘self-insert’ replace the
text at point rather than pushing the text to the right.
- Characters bound to 'backward-delete-char' replace the character
+ Characters bound to ‘backward-delete-char’ replace the character
before point with a space.
By default, this command is unbound.
8.4.4 Killing And Yanking
-------------------------
-'kill-line (C-k)'
+‘kill-line (C-k)’
Kill the text from point to the end of the line. With a negative
numeric argument, kill backward from the cursor to the beginning of
the current line.
-'backward-kill-line (C-x Rubout)'
+‘backward-kill-line (C-x Rubout)’
Kill backward from the cursor to the beginning of the current line.
With a negative numeric argument, kill forward from the cursor to
the end of the current line.
-'unix-line-discard (C-u)'
+‘unix-line-discard (C-u)’
Kill backward from the cursor to the beginning of the current line.
-'kill-whole-line ()'
+‘kill-whole-line ()’
Kill all characters on the current line, no matter where point is.
By default, this is unbound.
-'kill-word (M-d)'
+‘kill-word (M-d)’
Kill from point to the end of the current word, or if between
words, to the end of the next word. Word boundaries are the same
- as 'forward-word'.
+ as ‘forward-word’.
-'backward-kill-word (M-<DEL>)'
+‘backward-kill-word (M-<DEL>)’
Kill the word behind point. Word boundaries are the same as
- 'backward-word'.
+ ‘backward-word’.
-'shell-kill-word (M-C-d)'
+‘shell-kill-word (M-C-d)’
Kill from point to the end of the current word, or if between
words, to the end of the next word. Word boundaries are the same
- as 'shell-forward-word'.
+ as ‘shell-forward-word’.
-'shell-backward-kill-word ()'
+‘shell-backward-kill-word ()’
Kill the word behind point. Word boundaries are the same as
- 'shell-backward-word'.
+ ‘shell-backward-word’.
-'unix-word-rubout (C-w)'
+‘unix-word-rubout (C-w)’
Kill the word behind point, using white space as a word boundary.
The killed text is saved on the kill-ring.
-'unix-filename-rubout ()'
+‘unix-filename-rubout ()’
Kill the word behind point, using white space and the slash
character as the word boundaries. The killed text is saved on the
kill-ring.
-'delete-horizontal-space ()'
+‘delete-horizontal-space ()’
Delete all spaces and tabs around point. By default, this is
unbound.
-'kill-region ()'
+‘kill-region ()’
Kill the text in the current region. By default, this command is
unbound.
-'copy-region-as-kill ()'
+‘copy-region-as-kill ()’
Copy the text in the region to the kill buffer, so it can be yanked
right away. By default, this command is unbound.
-'copy-backward-word ()'
+‘copy-backward-word ()’
Copy the word before point to the kill buffer. The word boundaries
- are the same as 'backward-word'. By default, this command is
+ are the same as ‘backward-word’. By default, this command is
unbound.
-'copy-forward-word ()'
+‘copy-forward-word ()’
Copy the word following point to the kill buffer. The word
- boundaries are the same as 'forward-word'. By default, this
+ boundaries are the same as ‘forward-word’. By default, this
command is unbound.
-'yank (C-y)'
+‘yank (C-y)’
Yank the top of the kill ring into the buffer at point.
-'yank-pop (M-y)'
+‘yank-pop (M-y)’
Rotate the kill-ring, and yank the new top. You can only do this
- if the prior command is 'yank' or 'yank-pop'.
+ if the prior command is ‘yank’ or ‘yank-pop’.
\1f
File: bash.info, Node: Numeric Arguments, Next: Commands For Completion, Prev: Commands For Killing, Up: Bindable Readline Commands
8.4.5 Specifying Numeric Arguments
----------------------------------
-'digit-argument (M-0, M-1, ... M--)'
+‘digit-argument (M-0, M-1, ... M--)’
Add this digit to the argument already accumulating, or start a new
- argument. 'M--' starts a negative argument.
+ argument. ‘M--’ starts a negative argument.
-'universal-argument ()'
+‘universal-argument ()’
This is another way to specify an argument. If this command is
followed by one or more digits, optionally with a leading minus
sign, those digits define the argument. If the command is followed
- by digits, executing 'universal-argument' again ends the numeric
+ by digits, executing ‘universal-argument’ again ends the numeric
argument, but is otherwise ignored. As a special case, if this
command is immediately followed by a character that is neither a
digit nor minus sign, the argument count for the next command is
8.4.6 Letting Readline Type For You
-----------------------------------
-'complete (<TAB>)'
+‘complete (<TAB>)’
Attempt to perform completion on the text before point. The actual
completion performed is application-specific. Bash attempts
completion treating the text as a variable (if the text begins with
- '$'), username (if the text begins with '~'), hostname (if the text
- begins with '@'), or command (including aliases and functions) in
+ ‘$’), username (if the text begins with ‘~’), hostname (if the text
+ begins with ‘@’), or command (including aliases and functions) in
turn. If none of these produces a match, filename completion is
attempted.
-'possible-completions (M-?)'
+‘possible-completions (M-?)’
List the possible completions of the text before point. When
displaying completions, Readline sets the number of columns used
- for display to the value of 'completion-display-width', the value
- of the environment variable 'COLUMNS', or the screen width, in that
+ for display to the value of ‘completion-display-width’, the value
+ of the environment variable ‘COLUMNS’, or the screen width, in that
order.
-'insert-completions (M-*)'
+‘insert-completions (M-*)’
Insert all completions of the text before point that would have
- been generated by 'possible-completions'.
+ been generated by ‘possible-completions’.
-'menu-complete ()'
- Similar to 'complete', but replaces the word to be completed with a
+‘menu-complete ()’
+ Similar to ‘complete’, but replaces the word to be completed with a
single match from the list of possible completions. Repeated
- execution of 'menu-complete' steps through the list of possible
+ execution of ‘menu-complete’ steps through the list of possible
completions, inserting each match in turn. At the end of the list
of completions, the bell is rung (subject to the setting of
- 'bell-style') and the original text is restored. An argument of N
+ ‘bell-style’) and the original text is restored. An argument of N
moves N positions forward in the list of matches; a negative
argument may be used to move backward through the list. This
command is intended to be bound to <TAB>, but is unbound by
default.
-'menu-complete-backward ()'
- Identical to 'menu-complete', but moves backward through the list
- of possible completions, as if 'menu-complete' had been given a
+‘menu-complete-backward ()’
+ Identical to ‘menu-complete’, but moves backward through the list
+ of possible completions, as if ‘menu-complete’ had been given a
negative argument.
-'delete-char-or-list ()'
+‘delete-char-or-list ()’
Deletes the character under the cursor if not at the beginning or
- end of the line (like 'delete-char'). If at the end of the line,
- behaves identically to 'possible-completions'. This command is
+ end of the line (like ‘delete-char’). If at the end of the line,
+ behaves identically to ‘possible-completions’. This command is
unbound by default.
-'complete-filename (M-/)'
+‘complete-filename (M-/)’
Attempt filename completion on the text before point.
-'possible-filename-completions (C-x /)'
+‘possible-filename-completions (C-x /)’
List the possible completions of the text before point, treating it
as a filename.
-'complete-username (M-~)'
+‘complete-username (M-~)’
Attempt completion on the text before point, treating it as a
username.
-'possible-username-completions (C-x ~)'
+‘possible-username-completions (C-x ~)’
List the possible completions of the text before point, treating it
as a username.
-'complete-variable (M-$)'
+‘complete-variable (M-$)’
Attempt completion on the text before point, treating it as a shell
variable.
-'possible-variable-completions (C-x $)'
+‘possible-variable-completions (C-x $)’
List the possible completions of the text before point, treating it
as a shell variable.
-'complete-hostname (M-@)'
+‘complete-hostname (M-@)’
Attempt completion on the text before point, treating it as a
hostname.
-'possible-hostname-completions (C-x @)'
+‘possible-hostname-completions (C-x @)’
List the possible completions of the text before point, treating it
as a hostname.
-'complete-command (M-!)'
+‘complete-command (M-!)’
Attempt completion on the text before point, treating it as a
command name. Command completion attempts to match the text
against aliases, reserved words, shell functions, shell builtins,
and finally executable filenames, in that order.
-'possible-command-completions (C-x !)'
+‘possible-command-completions (C-x !)’
List the possible completions of the text before point, treating it
as a command name.
-'dynamic-complete-history (M-<TAB>)'
+‘dynamic-complete-history (M-<TAB>)’
Attempt completion on the text before point, comparing the text
against lines from the history list for possible completion
matches.
-'dabbrev-expand ()'
+‘dabbrev-expand ()’
Attempt menu completion on the text before point, comparing the
text against lines from the history list for possible completion
matches.
-'complete-into-braces (M-{)'
+‘complete-into-braces (M-{)’
Perform filename completion and insert the list of possible
completions enclosed within braces so the list is available to the
shell (*note Brace Expansion::).
8.4.7 Keyboard Macros
---------------------
-'start-kbd-macro (C-x ()'
+‘start-kbd-macro (C-x ()’
Begin saving the characters typed into the current keyboard macro.
-'end-kbd-macro (C-x ))'
+‘end-kbd-macro (C-x ))’
Stop saving the characters typed into the current keyboard macro
and save the definition.
-'call-last-kbd-macro (C-x e)'
+‘call-last-kbd-macro (C-x e)’
Re-execute the last keyboard macro defined, by making the
characters in the macro appear as if typed at the keyboard.
-'print-last-kbd-macro ()'
+‘print-last-kbd-macro ()’
Print the last keyboard macro defined in a format suitable for the
INPUTRC file.
8.4.8 Some Miscellaneous Commands
---------------------------------
-'re-read-init-file (C-x C-r)'
+‘re-read-init-file (C-x C-r)’
Read in the contents of the INPUTRC file, and incorporate any
bindings or variable assignments found there.
-'abort (C-g)'
+‘abort (C-g)’
Abort the current editing command and ring the terminal's bell
- (subject to the setting of 'bell-style').
+ (subject to the setting of ‘bell-style’).
-'do-lowercase-version (M-A, M-B, M-X, ...)'
+‘do-lowercase-version (M-A, M-B, M-X, ...)’
If the metafied character X is upper case, run the command that is
bound to the corresponding metafied lower case character. The
behavior is undefined if X is already lower case.
-'prefix-meta (<ESC>)'
+‘prefix-meta (<ESC>)’
Metafy the next character typed. This is for keyboards without a
- meta key. Typing '<ESC> f' is equivalent to typing 'M-f'.
+ meta key. Typing ‘<ESC> f’ is equivalent to typing ‘M-f’.
-'undo (C-_ or C-x C-u)'
+‘undo (C-_ or C-x C-u)’
Incremental undo, separately remembered for each line.
-'revert-line (M-r)'
+‘revert-line (M-r)’
Undo all changes made to this line. This is like executing the
- 'undo' command enough times to get back to the beginning.
+ ‘undo’ command enough times to get back to the beginning.
-'tilde-expand (M-&)'
+‘tilde-expand (M-&)’
Perform tilde expansion on the current word.
-'set-mark (C-@)'
+‘set-mark (C-@)’
Set the mark to the point. If a numeric argument is supplied, the
mark is set to that position.
-'exchange-point-and-mark (C-x C-x)'
+‘exchange-point-and-mark (C-x C-x)’
Swap the point with the mark. The current cursor position is set
to the saved position, and the old cursor position is saved as the
mark.
-'character-search (C-])'
+‘character-search (C-])’
A character is read and point is moved to the next occurrence of
that character. A negative argument searches for previous
occurrences.
-'character-search-backward (M-C-])'
+‘character-search-backward (M-C-])’
A character is read and point is moved to the previous occurrence
of that character. A negative argument searches for subsequent
occurrences.
-'skip-csi-sequence ()'
+‘skip-csi-sequence ()’
Read enough characters to consume a multi-key sequence such as
those defined for keys like Home and End. Such sequences begin
with a Control Sequence Indicator (CSI), usually ESC-[. If this
inserting stray characters into the editing buffer. This is
unbound by default, but usually bound to ESC-[.
-'insert-comment (M-#)'
- Without a numeric argument, the value of the 'comment-begin'
+‘insert-comment (M-#)’
+ Without a numeric argument, the value of the ‘comment-begin’
variable is inserted at the beginning of the current line. If a
numeric argument is supplied, this command acts as a toggle: if the
characters at the beginning of the line do not match the value of
- 'comment-begin', the value is inserted, otherwise the characters in
- 'comment-begin' are deleted from the beginning of the line. In
+ ‘comment-begin’, the value is inserted, otherwise the characters in
+ ‘comment-begin’ are deleted from the beginning of the line. In
either case, the line is accepted as if a newline had been typed.
- The default value of 'comment-begin' causes this command to make
+ The default value of ‘comment-begin’ causes this command to make
the current line a shell comment. If a numeric argument causes the
comment character to be removed, the line will be executed by the
shell.
-'dump-functions ()'
+‘dump-functions ()’
Print all of the functions and their key bindings to the Readline
output stream. If a numeric argument is supplied, the output is
formatted in such a way that it can be made part of an INPUTRC
file. This command is unbound by default.
-'dump-variables ()'
+‘dump-variables ()’
Print all of the settable variables and their values to the
Readline output stream. If a numeric argument is supplied, the
output is formatted in such a way that it can be made part of an
INPUTRC file. This command is unbound by default.
-'dump-macros ()'
+‘dump-macros ()’
Print all of the Readline key sequences bound to macros and the
strings they output. If a numeric argument is supplied, the output
is formatted in such a way that it can be made part of an INPUTRC
file. This command is unbound by default.
-'spell-correct-word (C-x s)'
+‘spell-correct-word (C-x s)’
Perform spelling correction on the current word, treating it as a
- directory or filename, in the same way as the 'cdspell' shell
+ directory or filename, in the same way as the ‘cdspell’ shell
option. Word boundaries are the same as those used by
- 'shell-forward-word'.
+ ‘shell-forward-word’.
-'glob-complete-word (M-g)'
+‘glob-complete-word (M-g)’
The word before point is treated as a pattern for pathname
expansion, with an asterisk implicitly appended. This pattern is
used to generate a list of matching file names for possible
completions.
-'glob-expand-word (C-x *)'
+‘glob-expand-word (C-x *)’
The word before point is treated as a pattern for pathname
expansion, and the list of matching file names is inserted,
- replacing the word. If a numeric argument is supplied, a '*' is
+ replacing the word. If a numeric argument is supplied, a ‘*’ is
appended before pathname expansion.
-'glob-list-expansions (C-x g)'
+‘glob-list-expansions (C-x g)’
The list of expansions that would have been generated by
- 'glob-expand-word' is displayed, and the line is redrawn. If a
- numeric argument is supplied, a '*' is appended before pathname
+ ‘glob-expand-word’ is displayed, and the line is redrawn. If a
+ numeric argument is supplied, a ‘*’ is appended before pathname
expansion.
-'display-shell-version (C-x C-v)'
+‘display-shell-version (C-x C-v)’
Display version information about the current instance of Bash.
-'shell-expand-line (M-C-e)'
+‘shell-expand-line (M-C-e)’
Expand the line by performing shell word expansions. This performs
alias and history expansion, $'STRING' and $"STRING" quoting, tilde
expansion, parameter and variable expansion, arithmetic expansion,
- word splitting, and quote removal.
+ command and proces substitution, word splitting, and quote removal.
+ An explicit argument suppresses command and process substitution.
-'history-expand-line (M-^)'
+‘history-expand-line (M-^)’
Perform history expansion on the current line.
-'magic-space ()'
+‘magic-space ()’
Perform history expansion on the current line and insert a space
(*note History Interaction::).
-'alias-expand-line ()'
+‘alias-expand-line ()’
Perform alias expansion on the current line (*note Aliases::).
-'history-and-alias-expand-line ()'
+‘history-and-alias-expand-line ()’
Perform history and alias expansion on the current line.
-'insert-last-argument (M-. or M-_)'
- A synonym for 'yank-last-arg'.
+‘insert-last-argument (M-. or M-_)’
+ A synonym for ‘yank-last-arg’.
-'edit-and-execute-command (C-x C-e)'
+‘edit-and-execute-command (C-x C-e)’
Invoke an editor on the current command line, and execute the
- result as shell commands. Bash attempts to invoke '$VISUAL',
- '$EDITOR', and 'emacs' as the editor, in that order.
+ result as shell commands. Bash attempts to invoke ‘$VISUAL’,
+ ‘$EDITOR’, and ‘emacs’ as the editor, in that order.
-'execute-named-command (M-x)'
+‘execute-named-command (M-x)’
Read a bindable readline command name from the input and execute
the function to which it's bound, as if the key sequence to which
it was bound appeared in the input. If this function is supplied
8.5 Readline vi Mode
====================
-While the Readline library does not have a full set of 'vi' editing
+While the Readline library does not have a full set of ‘vi’ editing
functions, it does contain enough to allow simple editing of the line.
-The Readline 'vi' mode behaves as specified in the POSIX standard.
+The Readline ‘vi’ mode behaves as specified in the POSIX standard.
- In order to switch interactively between 'emacs' and 'vi' editing
-modes, use the 'set -o emacs' and 'set -o vi' commands (*note The Set
-Builtin::). The Readline default is 'emacs' mode.
+ In order to switch interactively between ‘emacs’ and ‘vi’ editing
+modes, use the ‘set -o emacs’ and ‘set -o vi’ commands (*note The Set
+Builtin::). The Readline default is ‘emacs’ mode.
- When you enter a line in 'vi' mode, you are already placed in
-'insertion' mode, as if you had typed an 'i'. Pressing <ESC> switches
+ When you enter a line in ‘vi’ mode, you are already placed in
+'insertion' mode, as if you had typed an ‘i’. Pressing <ESC> switches
you into 'command' mode, where you can edit the text of the line with
-the standard 'vi' movement keys, move to previous history lines with 'k'
-and subsequent lines with 'j', and so forth.
+the standard ‘vi’ movement keys, move to previous history lines with ‘k’
+and subsequent lines with ‘j’, and so forth.
\1f
File: bash.info, Node: Programmable Completion, Next: Programmable Completion Builtins, Prev: Readline vi Mode, Up: Command Line Editing
When word completion is attempted for an argument to a command for which
a completion specification (a COMPSPEC) has been defined using the
-'complete' builtin (*note Programmable Completion Builtins::), the
+‘complete’ builtin (*note Programmable Completion Builtins::), the
programmable completion facilities are invoked.
First, the command name is identified. If a compspec has been
defined for that command, the compspec is used to generate the list of
possible completions for the word. If the command word is the empty
string (completion attempted at the beginning of an empty line), any
-compspec defined with the '-E' option to 'complete' is used. If the
+compspec defined with the ‘-E’ option to ‘complete’ is used. If the
command word is a full pathname, a compspec for the full pathname is
searched for first. If no compspec is found for the full pathname, an
attempt is made to find a compspec for the portion following the final
slash. If those searches do not result in a compspec, any compspec
-defined with the '-D' option to 'complete' is used as the default. If
+defined with the ‘-D’ option to ‘complete’ is used as the default. If
there is no default compspec, Bash attempts alias expansion on the
command word as a final resort, and attempts to find a compspec for the
command word from any successful expansion
First, the actions specified by the compspec are used. Only matches
which are prefixed by the word being completed are returned. When the
-'-f' or '-d' option is used for filename or directory name completion,
-the shell variable 'FIGNORE' is used to filter the matches. *Note Bash
-Variables::, for a description of 'FIGNORE'.
+‘-f’ or ‘-d’ option is used for filename or directory name completion,
+the shell variable ‘FIGNORE’ is used to filter the matches. *Note Bash
+Variables::, for a description of ‘FIGNORE’.
- Any completions specified by a filename expansion pattern to the '-G'
+ Any completions specified by a filename expansion pattern to the ‘-G’
option are generated next. The words generated by the pattern need not
-match the word being completed. The 'GLOBIGNORE' shell variable is not
-used to filter the matches, but the 'FIGNORE' shell variable is used.
+match the word being completed. The ‘GLOBIGNORE’ shell variable is not
+used to filter the matches, but the ‘FIGNORE’ shell variable is used.
- Next, the string specified as the argument to the '-W' option is
-considered. The string is first split using the characters in the 'IFS'
+ Next, the string specified as the argument to the ‘-W’ option is
+considered. The string is first split using the characters in the ‘IFS’
special variable as delimiters. Shell quoting is honored within the
string, in order to provide a mechanism for the words to contain shell
-metacharacters or characters in the value of 'IFS'. Each word is then
+metacharacters or characters in the value of ‘IFS’. Each word is then
expanded using brace expansion, tilde expansion, parameter and variable
expansion, command substitution, and arithmetic expansion, as described
above (*note Shell Expansions::). The results are split using the rules
words become the possible completions.
After these matches have been generated, any shell function or
-command specified with the '-F' and '-C' options is invoked. When the
-command or function is invoked, the 'COMP_LINE', 'COMP_POINT',
-'COMP_KEY', and 'COMP_TYPE' variables are assigned values as described
+command specified with the ‘-F’ and ‘-C’ options is invoked. When the
+command or function is invoked, the ‘COMP_LINE’, ‘COMP_POINT’,
+‘COMP_KEY’, and ‘COMP_TYPE’ variables are assigned values as described
above (*note Bash Variables::). If a shell function is being invoked,
-the 'COMP_WORDS' and 'COMP_CWORD' variables are also set. When the
+the ‘COMP_WORDS’ and ‘COMP_CWORD’ variables are also set. When the
function or command is invoked, the first argument ($1) is the name of
the command whose arguments are being completed, the second argument
($2) is the word being completed, and the third argument ($3) is the
is performed; the function or command has complete freedom in generating
the matches.
- Any function specified with '-F' is invoked first. The function may
-use any of the shell facilities, including the 'compgen' and 'compopt'
+ Any function specified with ‘-F’ is invoked first. The function may
+use any of the shell facilities, including the ‘compgen’ and ‘compopt’
builtins described below (*note Programmable Completion Builtins::), to
generate the matches. It must put the possible completions in the
-'COMPREPLY' array variable, one per array element.
+‘COMPREPLY’ array variable, one per array element.
- Next, any command specified with the '-C' option is invoked in an
+ Next, any command specified with the ‘-C’ option is invoked in an
environment equivalent to command substitution. It should print a list
of completions, one per line, to the standard output. Backslash may be
used to escape a newline, if necessary.
After all of the possible completions are generated, any filter
-specified with the '-X' option is applied to the list. The filter is a
-pattern as used for pathname expansion; a '&' in the pattern is replaced
-with the text of the word being completed. A literal '&' may be escaped
+specified with the ‘-X’ option is applied to the list. The filter is a
+pattern as used for pathname expansion; a ‘&’ in the pattern is replaced
+with the text of the word being completed. A literal ‘&’ may be escaped
with a backslash; the backslash is removed before attempting a match.
Any completion that matches the pattern will be removed from the list.
-A leading '!' negates the pattern; in this case any completion not
-matching the pattern will be removed. If the 'nocasematch' shell option
-(see the description of 'shopt' in *note The Shopt Builtin::) is
+A leading ‘!’ negates the pattern; in this case any completion not
+matching the pattern will be removed. If the ‘nocasematch’ shell option
+(see the description of ‘shopt’ in *note The Shopt Builtin::) is
enabled, the match is performed without regard to the case of alphabetic
characters.
- Finally, any prefix and suffix specified with the '-P' and '-S'
+ Finally, any prefix and suffix specified with the ‘-P’ and ‘-S’
options are added to each member of the completion list, and the result
is returned to the Readline completion code as the list of possible
completions.
If the previously-applied actions do not generate any matches, and
-the '-o dirnames' option was supplied to 'complete' when the compspec
+the ‘-o dirnames’ option was supplied to ‘complete’ when the compspec
was defined, directory name completion is attempted.
- If the '-o plusdirs' option was supplied to 'complete' when the
+ If the ‘-o plusdirs’ option was supplied to ‘complete’ when the
compspec was defined, directory name completion is attempted and any
matches are added to the results of the other actions.
By default, if a compspec is found, whatever it generates is returned
to the completion code as the full set of possible completions. The
default Bash completions are not attempted, and the Readline default of
-filename completion is disabled. If the '-o bashdefault' option was
-supplied to 'complete' when the compspec was defined, the default Bash
+filename completion is disabled. If the ‘-o bashdefault’ option was
+supplied to ‘complete’ when the compspec was defined, the default Bash
completions are attempted if the compspec generates no matches. If the
-'-o default' option was supplied to 'complete' when the compspec was
+‘-o default’ option was supplied to ‘complete’ when the compspec was
defined, Readline's default completion will be performed if the compspec
(and, if attempted, the default Bash completions) generate no matches.
There is some support for dynamically modifying completions. This is
most useful when used in combination with a default completion specified
-with '-D'. It's possible for shell functions executed as completion
+with ‘-D’. It's possible for shell functions executed as completion
handlers to indicate that completion should be retried by returning an
exit status of 124. If a shell function returns 124, and changes the
compspec associated with the command on which completion is being
command are to be completed, and two to modify the completion as it is
happening.
-'compgen'
+‘compgen’
compgen [-V VARNAME] [OPTION] [WORD]
Generate possible completion matches for WORD according to the
- OPTIONs, which may be any option accepted by the 'complete' builtin
- with the exceptions of '-p', '-r', '-D', '-E', and '-I', and write
+ OPTIONs, which may be any option accepted by the ‘complete’ builtin
+ with the exceptions of ‘-p’, ‘-r’, ‘-D’, ‘-E’, and ‘-I’, and write
the matches to the standard output.
- If the '-V' option is supplied, 'compgen' stores the generated
+ If the ‘-V’ option is supplied, ‘compgen’ stores the generated
completions into the indexed array variable VARNAME instead of
writing them to the standard output.
- When using the '-F' or '-C' options, the various shell variables
+ When using the ‘-F’ or ‘-C’ options, the various shell variables
set by the programmable completion facilities, while available,
will not have useful values.
The return value is true unless an invalid option is supplied, or
no matches were generated.
-'complete'
+‘complete’
complete [-abcdefgjksuv] [-o COMP-OPTION] [-DEI] [-A ACTION]
[-G GLOBPAT] [-W WORDLIST] [-F FUNCTION] [-C COMMAND]
[-X FILTERPAT] [-P PREFIX] [-S SUFFIX] NAME [NAME ...]
complete -pr [-DEI] [NAME ...]
Specify how arguments to each NAME should be completed. If the
- '-p' option is supplied, or if no options are supplied, existing
- completion specifications are printed in a way that allows them to
- be reused as input. The '-r' option removes a completion
+ ‘-p’ option is supplied, or if no options or NAMEs are supplied,
+ existing completion specifications are printed in a way that allows
+ them to be reused as input. The ‘-r’ option removes a completion
specification for each NAME, or, if no NAMEs are supplied, all
- completion specifications. The '-D' option indicates that other
+ completion specifications. The ‘-D’ option indicates that other
supplied options and actions should apply to the "default" command
completion; that is, completion attempted on a command for which no
- completion has previously been defined. The '-E' option indicates
+ completion has previously been defined. The ‘-E’ option indicates
that other supplied options and actions should apply to "empty"
command completion; that is, completion attempted on a blank line.
- The '-I' option indicates that other supplied options and actions
+ The ‘-I’ option indicates that other supplied options and actions
should apply to completion on the initial non-assignment word on
- the line, or after a command delimiter such as ';' or '|', which is
+ the line, or after a command delimiter such as ‘;’ or ‘|’, which is
usually command name completion. If multiple options are supplied,
- the '-D' option takes precedence over '-E', and both take
- precedence over '-I'. If any of '-D', '-E', or '-I' are supplied,
+ the ‘-D’ option takes precedence over ‘-E’, and both take
+ precedence over ‘-I’. If any of ‘-D’, ‘-E’, or ‘-I’ are supplied,
any other NAME arguments are ignored; these completions only apply
to the case specified by the option.
Completion::).
Other options, if specified, have the following meanings. The
- arguments to the '-G', '-W', and '-X' options (and, if necessary,
- the '-P' and '-S' options) should be quoted to protect them from
- expansion before the 'complete' builtin is invoked.
+ arguments to the ‘-G’, ‘-W’, and ‘-X’ options (and, if necessary,
+ the ‘-P’ and ‘-S’ options) should be quoted to protect them from
+ expansion before the ‘complete’ builtin is invoked.
- '-o COMP-OPTION'
+ ‘-o COMP-OPTION’
The COMP-OPTION controls several aspects of the compspec's
behavior beyond the simple generation of completions.
COMP-OPTION may be one of:
- 'bashdefault'
+ ‘bashdefault’
Perform the rest of the default Bash completions if the
compspec generates no matches.
- 'default'
+ ‘default’
Use Readline's default filename completion if the
compspec generates no matches.
- 'dirnames'
+ ‘dirnames’
Perform directory name completion if the compspec
generates no matches.
- 'filenames'
+ ‘filenames’
Tell Readline that the compspec generates filenames, so
it can perform any filename-specific processing (like
adding a slash to directory names, quoting special
characters, or suppressing trailing spaces). This option
is intended to be used with shell functions specified
- with '-F'.
+ with ‘-F’.
- 'fullquote'
+ ‘fullquote’
Tell Readline to quote all the completed words even if
they are not filenames.
- 'noquote'
+ ‘noquote’
Tell Readline not to quote the completed words if they
are filenames (quoting filenames is the default).
- 'nosort'
+ ‘nosort’
Tell Readline not to sort the list of possible
completions alphabetically.
- 'nospace'
+ ‘nospace’
Tell Readline not to append a space (the default) to
words completed at the end of the line.
- 'plusdirs'
+ ‘plusdirs’
After any matches defined by the compspec are generated,
directory name completion is attempted and any matches
are added to the results of the other actions.
- '-A ACTION'
+ ‘-A ACTION’
The ACTION may be one of the following to generate a list of
possible completions:
- 'alias'
- Alias names. May also be specified as '-a'.
+ ‘alias’
+ Alias names. May also be specified as ‘-a’.
- 'arrayvar'
+ ‘arrayvar’
Array variable names.
- 'binding'
+ ‘binding’
Readline key binding names (*note Bindable Readline
Commands::).
- 'builtin'
+ ‘builtin’
Names of shell builtin commands. May also be specified
- as '-b'.
+ as ‘-b’.
- 'command'
- Command names. May also be specified as '-c'.
+ ‘command’
+ Command names. May also be specified as ‘-c’.
- 'directory'
- Directory names. May also be specified as '-d'.
+ ‘directory’
+ Directory names. May also be specified as ‘-d’.
- 'disabled'
+ ‘disabled’
Names of disabled shell builtins.
- 'enabled'
+ ‘enabled’
Names of enabled shell builtins.
- 'export'
+ ‘export’
Names of exported shell variables. May also be specified
- as '-e'.
+ as ‘-e’.
- 'file'
- File names. May also be specified as '-f'.
+ ‘file’
+ File names. May also be specified as ‘-f’.
- 'function'
+ ‘function’
Names of shell functions.
- 'group'
- Group names. May also be specified as '-g'.
+ ‘group’
+ Group names. May also be specified as ‘-g’.
- 'helptopic'
- Help topics as accepted by the 'help' builtin (*note Bash
+ ‘helptopic’
+ Help topics as accepted by the ‘help’ builtin (*note Bash
Builtins::).
- 'hostname'
+ ‘hostname’
Hostnames, as taken from the file specified by the
- 'HOSTFILE' shell variable (*note Bash Variables::).
+ ‘HOSTFILE’ shell variable (*note Bash Variables::).
- 'job'
+ ‘job’
Job names, if job control is active. May also be
- specified as '-j'.
+ specified as ‘-j’.
- 'keyword'
- Shell reserved words. May also be specified as '-k'.
+ ‘keyword’
+ Shell reserved words. May also be specified as ‘-k’.
- 'running'
+ ‘running’
Names of running jobs, if job control is active.
- 'service'
- Service names. May also be specified as '-s'.
+ ‘service’
+ Service names. May also be specified as ‘-s’.
- 'setopt'
- Valid arguments for the '-o' option to the 'set' builtin
+ ‘setopt’
+ Valid arguments for the ‘-o’ option to the ‘set’ builtin
(*note The Set Builtin::).
- 'shopt'
- Shell option names as accepted by the 'shopt' builtin
+ ‘shopt’
+ Shell option names as accepted by the ‘shopt’ builtin
(*note Bash Builtins::).
- 'signal'
+ ‘signal’
Signal names.
- 'stopped'
+ ‘stopped’
Names of stopped jobs, if job control is active.
- 'user'
- User names. May also be specified as '-u'.
+ ‘user’
+ User names. May also be specified as ‘-u’.
- 'variable'
+ ‘variable’
Names of all shell variables. May also be specified as
- '-v'.
+ ‘-v’.
- '-C COMMAND'
+ ‘-C COMMAND’
COMMAND is executed in a subshell environment, and its output
is used as the possible completions. Arguments are passed as
- with the '-F' option.
+ with the ‘-F’ option.
- '-F FUNCTION'
+ ‘-F FUNCTION’
The shell function FUNCTION is executed in the current shell
environment. When it is executed, $1 is the name of the
command whose arguments are being completed, $2 is the word
being completed, and $3 is the word preceding the word being
completed, as described above (*note Programmable
Completion::). When it finishes, the possible completions are
- retrieved from the value of the 'COMPREPLY' array variable.
+ retrieved from the value of the ‘COMPREPLY’ array variable.
- '-G GLOBPAT'
+ ‘-G GLOBPAT’
The filename expansion pattern GLOBPAT is expanded to generate
the possible completions.
- '-P PREFIX'
+ ‘-P PREFIX’
PREFIX is added at the beginning of each possible completion
after all other options have been applied.
- '-S SUFFIX'
+ ‘-S SUFFIX’
SUFFIX is appended to each possible completion after all other
options have been applied.
- '-W WORDLIST'
- The WORDLIST is split using the characters in the 'IFS'
+ ‘-W WORDLIST’
+ The WORDLIST is split using the characters in the ‘IFS’
special variable as delimiters, and each resultant word is
expanded. The possible completions are the members of the
resultant list which match the word being completed.
- '-X FILTERPAT'
+ ‘-X FILTERPAT’
FILTERPAT is a pattern as used for filename expansion. It is
applied to the list of possible completions generated by the
preceding options and arguments, and each completion matching
- FILTERPAT is removed from the list. A leading '!' in
+ FILTERPAT is removed from the list. A leading ‘!’ in
FILTERPAT negates the pattern; in this case, any completion
not matching FILTERPAT is removed.
The return value is true unless an invalid option is supplied, an
- option other than '-p', '-r', '-D', '-E', or '-I' is supplied
+ option other than ‘-p’, ‘-r’, ‘-D’, ‘-E’, or ‘-I’ is supplied
without a NAME argument, an attempt is made to remove a completion
specification for a NAME for which no specification exists, or an
error occurs adding a completion specification.
-'compopt'
+‘compopt’
compopt [-o OPTION] [-DEI] [+o OPTION] [NAME]
Modify completion options for each NAME according to the OPTIONs,
or for the currently-executing completion if no NAMEs are supplied.
If no OPTIONs are given, display the completion options for each
NAME or the current completion. The possible values of OPTION are
- those valid for the 'complete' builtin described above. The '-D'
+ those valid for the ‘complete’ builtin described above. The ‘-D’
option indicates that other supplied options should apply to the
"default" command completion; that is, completion attempted on a
command for which no completion has previously been defined. The
- '-E' option indicates that other supplied options should apply to
+ ‘-E’ option indicates that other supplied options should apply to
"empty" command completion; that is, completion attempted on a
- blank line. The '-I' option indicates that other supplied options
+ blank line. The ‘-I’ option indicates that other supplied options
should apply to completion on the initial non-assignment word on
- the line, or after a command delimiter such as ';' or '|', which is
+ the line, or after a command delimiter such as ‘;’ or ‘|’, which is
usually command name completion.
- If multiple options are supplied, the '-D' option takes precedence
- over '-E', and both take precedence over '-I'
+ If multiple options are supplied, the ‘-D’ option takes precedence
+ over ‘-E’, and both take precedence over ‘-I’
The return value is true unless an invalid option is supplied, an
attempt is made to modify the options for a NAME for which no
=====================================
The most common way to obtain additional completion functionality beyond
-the default actions 'complete' and 'compgen' provide is to use a shell
-function and bind it to a particular command using 'complete -F'.
+the default actions ‘complete’ and ‘compgen’ provide is to use a shell
+function and bind it to a particular command using ‘complete -F’.
- The following function provides completions for the 'cd' builtin. It
+ The following function provides completions for the ‘cd’ builtin. It
is a reasonably good example of what shell functions must do when used
-for completion. This function uses the word passed as '$2' to determine
-the directory name to complete. You can also use the 'COMP_WORDS' array
-variable; the current word is indexed by the 'COMP_CWORD' variable.
+for completion. This function uses the word passed as ‘$2’ to determine
+the directory name to complete. You can also use the ‘COMP_WORDS’ array
+variable; the current word is indexed by the ‘COMP_CWORD’ variable.
- The function relies on the 'complete' and 'compgen' builtins to do
-much of the work, adding only the things that the Bash 'cd' does beyond
+ The function relies on the ‘complete’ and ‘compgen’ builtins to do
+much of the work, adding only the things that the Bash ‘cd’ does beyond
accepting basic directory names: tilde expansion (*note Tilde
Expansion::), searching directories in $CDPATH, which is described above
-(*note Bourne Shell Builtins::), and basic support for the 'cdable_vars'
-shell option (*note The Shopt Builtin::). '_comp_cd' modifies the value
+(*note Bourne Shell Builtins::), and basic support for the ‘cdable_vars’
+shell option (*note The Shopt Builtin::). ‘_comp_cd’ modifies the value
of IFS so that it contains only a newline to accommodate file names
-containing spaces and tabs - 'compgen' prints the possible completions
+containing spaces and tabs - ‘compgen’ prints the possible completions
it generates one per line.
Possible completions go into the COMPREPLY array variable, one
return 0
}
- We install the completion function using the '-F' option to
-'complete':
+ We install the completion function using the ‘-F’ option to
+‘complete’:
# Tell readline to quote appropriate and append slashes to directories;
# use the bash default completion for other arguments
Since we'd like Bash and Readline to take care of some of the other
details for us, we use several other options to tell Bash and Readline
-what to do. The '-o filenames' option tells Readline that the possible
+what to do. The ‘-o filenames’ option tells Readline that the possible
completions should be treated as filenames, and quoted appropriately.
That option will also cause Readline to append a slash to filenames it
can determine are directories (which is why we might want to extend
-'_comp_cd' to append a slash if we're using directories found via
-CDPATH: Readline can't tell those completions are directories). The '-o
-nospace' option tells Readline to not append a space character to the
-directory name, in case we want to append to it. The '-o bashdefault'
+‘_comp_cd’ to append a slash if we're using directories found via
+CDPATH: Readline can't tell those completions are directories). The ‘-o
+nospace’ option tells Readline to not append a space character to the
+directory name, in case we want to append to it. The ‘-o bashdefault’
option brings in the rest of the "Bash default" completions - possible
completions that Bash adds to the default Readline set. These include
things like command name completion, variable completion for words
-beginning with '$' or '${', completions containing pathname expansion
+beginning with ‘$’ or ‘${’, completions containing pathname expansion
patterns (*note Filename Expansion::), and so on.
- Once installed using 'complete', '_comp_cd' will be called every time
-we attempt word completion for a 'cd' command.
+ Once installed using ‘complete’, ‘_comp_cd’ will be called every time
+we attempt word completion for a ‘cd’ command.
Many more examples - an extensive collection of completions for most
of the common GNU, Unix, and Linux commands - are available as part of
are ports for other systems such as Solaris and Mac OS X.
An older version of the bash_completion package is distributed with
-bash in the 'examples/complete' subdirectory.
+bash in the ‘examples/complete’ subdirectory.
\1f
File: bash.info, Node: Using History Interactively, Next: Installing Bash, Prev: Command Line Editing, Up: Top
9.1 Bash History Facilities
===========================
-When the '-o history' option to the 'set' builtin is enabled (*note The
-Set Builtin::), the shell provides access to the "command history", the
-list of commands previously typed. The value of the 'HISTSIZE' shell
+When the ‘-o history’ option to the ‘set’ builtin is enabled (*note The
+Set Builtin::), the shell provides access to the “command history”, the
+list of commands previously typed. The value of the ‘HISTSIZE’ shell
variable is used as the number of commands to save in a history list.
-The text of the last '$HISTSIZE' commands (default 500) is saved. The
+The text of the last ‘$HISTSIZE’ commands (default 500) is saved. The
shell stores each command in the history list prior to parameter and
variable expansion but after history expansion is performed, subject to
-the values of the shell variables 'HISTIGNORE' and 'HISTCONTROL'.
+the values of the shell variables ‘HISTIGNORE’ and ‘HISTCONTROL’.
When the shell starts up, the history is initialized from the file
-named by the 'HISTFILE' variable (default '~/.bash_history'). The file
-named by the value of 'HISTFILE' is truncated, if necessary, to contain
+named by the ‘HISTFILE’ variable (default ‘~/.bash_history’). The file
+named by the value of ‘HISTFILE’ is truncated, if necessary, to contain
no more than the number of lines specified by the value of the
-'HISTFILESIZE' variable. When a shell with history enabled exits, the
-last '$HISTSIZE' lines are copied from the history list to the file
-named by '$HISTFILE'. If the 'histappend' shell option is set (*note
+‘HISTFILESIZE’ variable. When a shell with history enabled exits, the
+last ‘$HISTSIZE’ lines are copied from the history list to the file
+named by ‘$HISTFILE’. If the ‘histappend’ shell option is set (*note
Bash Builtins::), the lines are appended to the history file, otherwise
-the history file is overwritten. If 'HISTFILE' is unset or null, or if
+the history file is overwritten. If ‘HISTFILE’ is unset or null, or if
the history file is unwritable, the history is not saved. After saving
the history, the history file is truncated to contain no more than
-'$HISTFILESIZE' lines. If 'HISTFILESIZE' is unset, or set to null, a
+‘$HISTFILESIZE’ lines. If ‘HISTFILESIZE’ is unset, or set to null, a
non-numeric value, or a numeric value less than zero, the history file
is not truncated.
- If the 'HISTTIMEFORMAT' is set, the time stamp information associated
+ If the ‘HISTTIMEFORMAT’ is set, the time stamp information associated
with each history entry is written to the history file, marked with the
history comment character. When the history file is read, lines
beginning with the history comment character followed immediately by a
digit are interpreted as timestamps for the following history entry.
- The 'fc' builtin command may be used to list or edit and re-execute a
-portion of the history list. The 'history' builtin may be used to
+ The ‘fc’ builtin command may be used to list or edit and re-execute a
+portion of the history list. The ‘history’ builtin may be used to
display or modify the history list and manipulate the history file.
When using command-line editing, search commands are available in each
editing mode that provide access to the history list (*note Commands For
History::).
The shell allows control over which commands are saved on the history
-list. The 'HISTCONTROL' and 'HISTIGNORE' variables are used to cause
-the shell to save only a subset of the commands entered. The 'cmdhist'
+list. The ‘HISTCONTROL’ and ‘HISTIGNORE’ variables are used to cause
+the shell to save only a subset of the commands entered. The ‘cmdhist’
shell option, if enabled, causes the shell to attempt to save each line
of a multi-line command in the same history entry, adding semicolons
-where necessary to preserve syntactic correctness. The 'lithist' shell
+where necessary to preserve syntactic correctness. The ‘lithist’ shell
option causes the shell to save the command with embedded newlines
-instead of semicolons. The 'shopt' builtin is used to set these
-options. *Note The Shopt Builtin::, for a description of 'shopt'.
+instead of semicolons. The ‘shopt’ builtin is used to set these
+options. *Note The Shopt Builtin::, for a description of ‘shopt’.
\1f
File: bash.info, Node: Bash History Builtins, Next: History Interaction, Prev: Bash History Facilities, Up: Using History Interactively
Bash provides two builtin commands which manipulate the history list and
history file.
-'fc'
+‘fc’
fc [-e ENAME] [-lnr] [FIRST] [LAST]
fc -s [PAT=REP] [COMMAND]
from the current command number).
When listing, a FIRST or LAST of 0 is equivalent to -1 and -0 is
- equivalent to the current command (usually the 'fc' command);
+ equivalent to the current command (usually the ‘fc’ command);
otherwise 0 is equivalent to -1 and -0 is invalid.
If LAST is not specified, it is set to FIRST. If FIRST is not
- specified, it is set to the previous command for editing and -16
- for listing. If the '-l' flag is given, the commands are listed on
- standard output. The '-n' flag suppresses the command numbers when
- listing. The '-r' flag reverses the order of the listing.
+ specified, it is set to the previous command for editing and −16
+ for listing. If the ‘-l’ flag is given, the commands are listed on
+ standard output. The ‘-n’ flag suppresses the command numbers when
+ listing. The ‘-r’ flag reverses the order of the listing.
Otherwise, the editor given by ENAME is invoked on a file
containing those commands. If ENAME is not given, the value of the
- following variable expansion is used: '${FCEDIT:-${EDITOR:-vi}}'.
- This says to use the value of the 'FCEDIT' variable if set, or the
- value of the 'EDITOR' variable if that is set, or 'vi' if neither
+ following variable expansion is used: ‘${FCEDIT:-${EDITOR:-vi}}’.
+ This says to use the value of the ‘FCEDIT’ variable if set, or the
+ value of the ‘EDITOR’ variable if that is set, or ‘vi’ if neither
is set. When editing is complete, the edited commands are echoed
and executed.
PAT in the selected command is replaced by REP. COMMAND is
interpreted the same as FIRST above.
- A useful alias to use with the 'fc' command is 'r='fc -s'', so that
- typing 'r cc' runs the last command beginning with 'cc' and typing
- 'r' re-executes the last command (*note Aliases::).
+ A useful alias to use with the ‘fc’ command is ‘r='fc -s'’, so that
+ typing ‘r cc’ runs the last command beginning with ‘cc’ and typing
+ ‘r’ re-executes the last command (*note Aliases::).
-'history'
+‘history’
history [N]
history -c
history -d OFFSET
history -ps ARG
With no options, display the history list with line numbers. Lines
- prefixed with a '*' have been modified. An argument of N lists
- only the last N lines. If the shell variable 'HISTTIMEFORMAT' is
- set and not null, it is used as a format string for STRFTIME to
- display the time stamp associated with each displayed history
+ prefixed with a ‘*’ have been modified. An argument of N lists
+ only the last N lines. If the shell variable ‘HISTTIMEFORMAT’ is
+ set and not null, it is used as a format string for ‘strftime’(3)
+ to display the time stamp associated with each displayed history
entry. No intervening blank is printed between the formatted time
stamp and the history line.
Options, if supplied, have the following meanings:
- '-c'
+ ‘-c’
Clear the history list. This may be combined with the other
options to replace the history list completely.
- '-d OFFSET'
+ ‘-d OFFSET’
Delete the history entry at position OFFSET. If OFFSET is
positive, it should be specified as it appears when the
history is displayed. If OFFSET is negative, it is
interpreted as relative to one greater than the last history
position, so negative indices count back from the end of the
- history, and an index of '-1' refers to the current 'history
- -d' command.
+ history, and an index of ‘-1’ refers to the current ‘history
+ -d’ command.
- '-d START-END'
+ ‘-d START-END’
Delete the range of history entries between positions START
and END, inclusive. Positive and negative values for START
and END are interpreted as described above.
- '-a'
+ ‘-a’
Append the new history lines to the history file. These are
history lines entered since the beginning of the current Bash
session, but not already appended to the history file.
- '-n'
+ ‘-n’
Append the history lines not already read from the history
file to the current history list. These are lines appended to
the history file since the beginning of the current Bash
session.
- '-r'
+ ‘-r’
Read the history file and append its contents to the history
list.
- '-w'
+ ‘-w’
Write out the current history list to the history file.
- '-p'
+ ‘-p’
Perform history substitution on the ARGs and display the
result on the standard output, without storing the results in
the history list.
- '-s'
+ ‘-s’
The ARGs are added to the end of the history list as a single
entry.
- If a FILENAME argument is supplied when any of the '-w', '-r',
- '-a', or '-n' options is used, Bash uses FILENAME as the history
- file. If not, then the value of the 'HISTFILE' variable is used.
- If 'HISTFILE' is unset or null, these options have no effect.
+ If a FILENAME argument is supplied when any of the ‘-w’, ‘-r’,
+ ‘-a’, or ‘-n’ options is used, Bash uses FILENAME as the history
+ file. If not, then the value of the ‘HISTFILE’ variable is used.
+ If ‘HISTFILE’ is unset or null, these options have no effect.
The return value is 0 unless an invalid option is encountered, an
error occurs while reading or writing the history file, an invalid
- OFFSET or range is supplied as an argument to '-d', or the history
- expansion supplied as an argument to '-p' fails.
+ OFFSET or range is supplied as an argument to ‘-d’, or the history
+ expansion supplied as an argument to ‘-p’ fails.
\1f
File: bash.info, Node: History Interaction, Prev: Bash History Builtins, Up: Using History Interactively
=====================
The History library provides a history expansion feature that is similar
-to the history expansion provided by 'csh'. This section describes the
+to the history expansion provided by ‘csh’. This section describes the
syntax used to manipulate the history information.
History expansions introduce words from the history list into the
substitution. The second is to select portions of that line for
inclusion into the current one.
- The line selected from the history is called the "event", and the
-portions of that line that are acted upon are called "words". The line
+ The line selected from the history is called the “event”, and the
+portions of that line that are acted upon are called “words”. The line
is broken into words in the same fashion that Bash does, so that several
-words surrounded by quotes are considered one word. The "event
-designator" selects the event, the optional "word designator" selects
-words from the event, and various optional "modifiers" are available to
+words surrounded by quotes are considered one word. The “event
+designator” selects the event, the optional “word designator” selects
+words from the event, and various optional “modifiers” are available to
manipulate the selected words.
History expansions are introduced by the appearance of the history
-expansion character, which is '!' by default. History expansions may
+expansion character, which is ‘!’ by default. History expansions may
appear anywhere in the input, but do not nest.
History expansion implements shell-like quoting conventions: a
escape the history expansion character, but single quotes may not, since
they are not treated specially within double quotes.
- When using the shell, only '\' and ''' may be used to escape the
+ When using the shell, only ‘\’ and ‘'’ may be used to escape the
history expansion character, but the history expansion character is also
treated as quoted if it immediately precedes the closing double quote in
a double-quoted string.
There is a special abbreviation for substitution, active when the
-QUICK SUBSTITUTION character (default '^') is the first character on the
+QUICK SUBSTITUTION character (default ‘^’) is the first character on the
line. It selects the previous history list entry, using an event
-designator equivalent to '!!', and substitutes one string for another in
+designator equivalent to ‘!!’, and substitutes one string for another in
that line. It is described below (*note Event Designators::). This is
the only history expansion that does not begin with the history
expansion character.
- Several shell options settable with the 'shopt' builtin (*note The
+ Several shell options settable with the ‘shopt’ builtin (*note The
Shopt Builtin::) may be used to tailor the behavior of history
-expansion. If the 'histverify' shell option is enabled, and Readline is
+expansion. If the ‘histverify’ shell option is enabled, and Readline is
being used, history substitutions are not immediately passed to the
shell parser. Instead, the expanded line is reloaded into the Readline
editing buffer for further modification. If Readline is being used, and
-the 'histreedit' shell option is enabled, a failed history expansion
+the ‘histreedit’ shell option is enabled, a failed history expansion
will be reloaded into the Readline editing buffer for correction. The
-'-p' option to the 'history' builtin command may be used to see what a
-history expansion will do before using it. The '-s' option to the
-'history' builtin may be used to add commands to the end of the history
+‘-p’ option to the ‘history’ builtin command may be used to see what a
+history expansion will do before using it. The ‘-s’ option to the
+‘history’ builtin may be used to add commands to the end of the history
list without actually executing them, so that they are available for
subsequent recall. This is most useful in conjunction with Readline.
The shell allows control of the various characters used by the
-history expansion mechanism with the 'histchars' variable, as explained
+history expansion mechanism with the ‘histchars’ variable, as explained
above (*note Bash Variables::). The shell uses the history comment
character to mark history timestamps when writing the history file.
character, and ending with the word designator if one is present, or the
end of the word.
-'!'
+‘!’
Start a history substitution, except when followed by a space, tab,
- the end of the line, '=', or the rest of the shell metacharacters
+ the end of the line, ‘=’, or the rest of the shell metacharacters
defined above (*note Definitions::).
-'!N'
+‘!N’
Refer to command line N.
-'!-N'
+‘!-N’
Refer to the command N lines back.
-'!!'
- Refer to the previous command. This is a synonym for '!-1'.
+‘!!’
+ Refer to the previous command. This is a synonym for ‘!-1’.
-'!STRING'
+‘!STRING’
Refer to the most recent command preceding the current position in
the history list starting with STRING.
-'!?STRING[?]'
+‘!?STRING[?]’
Refer to the most recent command preceding the current position in
- the history list containing STRING. The trailing '?' may be
+ the history list containing STRING. The trailing ‘?’ may be
omitted if the STRING is followed immediately by a newline. If
STRING is missing, the string from the most recent search is used;
it is an error if there is no previous search string.
-'^STRING1^STRING2^'
+‘^STRING1^STRING2^’
Quick Substitution. Repeat the last command, replacing STRING1
- with STRING2. Equivalent to '!!:s^STRING1^STRING2^'.
+ with STRING2. Equivalent to ‘!!:s^STRING1^STRING2^’.
-'!#'
+‘!#’
The entire command line typed so far.
\1f
Word designators are used to select desired words from the event. They
are optional; if the word designator isn't supplied, the history
-expansion uses the entire event. A ':' separates the event
+expansion uses the entire event. A ‘:’ separates the event
specification from the word designator. It may be omitted if the word
-designator begins with a '^', '$', '*', '-', or '%'. Words are numbered
+designator begins with a ‘^’, ‘$’, ‘*’, ‘-’, or ‘%’. Words are numbered
from the beginning of the line, with the first word being denoted by 0
(zero). Words are inserted into the current line separated by single
spaces.
For example,
-'!!'
+‘!!’
designates the preceding command. When you type this, the
preceding command is repeated in toto.
-'!!:$'
+‘!!:$’
designates the last argument of the preceding command. This may be
- shortened to '!$'.
+ shortened to ‘!$’.
-'!fi:2'
+‘!fi:2’
designates the second argument of the most recent command starting
- with the letters 'fi'.
+ with the letters ‘fi’.
Here are the word designators:
-'0 (zero)'
- The '0'th word. For many applications, this is the command word.
+‘0 (zero)’
+ The ‘0’th word. For many applications, this is the command word.
-'N'
+‘N’
The Nth word.
-'^'
+‘^’
The first argument; that is, word 1.
-'$'
+‘$’
The last argument.
-'%'
- The first word matched by the most recent '?STRING?' search, if the
+‘%’
+ The first word matched by the most recent ‘?STRING?’ search, if the
search string begins with a character that is part of a word.
-'X-Y'
- A range of words; '-Y' abbreviates '0-Y'.
+‘X-Y’
+ A range of words; ‘-Y’ abbreviates ‘0-Y’.
-'*'
- All of the words, except the '0'th. This is a synonym for '1-$'.
- It is not an error to use '*' if there is just one word in the
+‘*’
+ All of the words, except the ‘0’th. This is a synonym for ‘1-$’.
+ It is not an error to use ‘*’ if there is just one word in the
event; the empty string is returned in that case.
-'X*'
- Abbreviates 'X-$'
+‘X*’
+ Abbreviates ‘X-$’
-'X-'
- Abbreviates 'X-$' like 'X*', but omits the last word. If 'x' is
+‘X-’
+ Abbreviates ‘X-$’ like ‘X*’, but omits the last word. If ‘x’ is
missing, it defaults to 0.
If a word designator is supplied without an event specification, the
---------------
After the optional word designator, you can add a sequence of one or
-more of the following modifiers, each preceded by a ':'. These modify,
+more of the following modifiers, each preceded by a ‘:’. These modify,
or edit, the word or words selected from the history event.
-'h'
+‘h’
Remove a trailing pathname component, leaving only the head.
-'t'
+‘t’
Remove all leading pathname components, leaving the tail.
-'r'
- Remove a trailing suffix of the form '.SUFFIX', leaving the
+‘r’
+ Remove a trailing suffix of the form ‘.SUFFIX’, leaving the
basename.
-'e'
+‘e’
Remove all but the trailing suffix.
-'p'
+‘p’
Print the new command but do not execute it.
-'q'
+‘q’
Quote the substituted words, escaping further substitutions.
-'x'
- Quote the substituted words as with 'q', but break into words at
- spaces, tabs, and newlines. The 'q' and 'x' modifiers are mutually
+‘x’
+ Quote the substituted words as with ‘q’, but break into words at
+ spaces, tabs, and newlines. The ‘q’ and ‘x’ modifiers are mutually
exclusive; the last one supplied is used.
-'s/OLD/NEW/'
+‘s/OLD/NEW/’
Substitute NEW for the first occurrence of OLD in the event line.
- Any character may be used as the delimiter in place of '/'. The
+ Any character may be used as the delimiter in place of ‘/’. The
delimiter may be quoted in OLD and NEW with a single backslash. If
- '&' appears in NEW, it is replaced by OLD. A single backslash will
- quote the '&'. If OLD is null, it is set to the last OLD
+ ‘&’ appears in NEW, it is replaced by OLD. A single backslash will
+ quote the ‘&’. If OLD is null, it is set to the last OLD
substituted, or, if no previous history substitutions took place,
- the last STRING in a !?STRING'[?]' search. If NEW is null, each
+ the last STRING in a !?STRING‘[?]’ search. If NEW is null, each
matching OLD is deleted. The final delimiter is optional if it is
the last character on the input line.
-'&'
+‘&’
Repeat the previous substitution.
-'g'
-'a'
+‘g’
+‘a’
Cause changes to be applied over the entire event line. Used in
- conjunction with 's', as in 'gs/OLD/NEW/', or with '&'.
+ conjunction with ‘s’, as in ‘gs/OLD/NEW/’, or with ‘&’.
-'G'
- Apply the following 's' or '&' modifier once to each word in the
+‘G’
+ Apply the following ‘s’ or ‘&’ modifier once to each word in the
event.
\1f
The simplest way to compile Bash is:
- 1. 'cd' to the directory containing the source code and type
- './configure' to configure Bash for your system. If you're using
- 'csh' on an old version of System V, you might need to type 'sh
- ./configure' instead to prevent 'csh' from trying to execute
- 'configure' itself.
+ 1. ‘cd’ to the directory containing the source code and type
+ ‘./configure’ to configure Bash for your system. If you're using
+ ‘csh’ on an old version of System V, you might need to type ‘sh
+ ./configure’ instead to prevent ‘csh’ from trying to execute
+ ‘configure’ itself.
- Running 'configure' takes some time. While running, it prints
+ Running ‘configure’ takes some time. While running, it prints
messages telling which features it is checking for.
- 2. Type 'make' to compile Bash and build the 'bashbug' bug reporting
+ 2. Type ‘make’ to compile Bash and build the ‘bashbug’ bug reporting
script.
- 3. Optionally, type 'make tests' to run the Bash test suite.
+ 3. Optionally, type ‘make tests’ to run the Bash test suite.
- 4. Type 'make install' to install 'bash' and 'bashbug'. This will
+ 4. Type ‘make install’ to install ‘bash’ and ‘bashbug’. This will
also install the manual pages and Info file, message translation
files, some supplemental documentation, a number of example
loadable builtin commands, and a set of header files for developing
loadable builtins. You may need additional privileges to install
- 'bash' to your desired destination, so 'sudo make install' might be
+ ‘bash’ to your desired destination, so ‘sudo make install’ might be
required. More information about controlling the locations where
- 'bash' and other files are installed is below (*note Installation
+ ‘bash’ and other files are installed is below (*note Installation
Names::).
- The 'configure' shell script attempts to guess correct values for
+ The ‘configure’ shell script attempts to guess correct values for
various system-dependent variables used during compilation. It uses
-those values to create a 'Makefile' in each directory of the package
-(the top directory, the 'builtins', 'doc', 'po', and 'support'
-directories, each directory under 'lib', and several others). It also
-creates a 'config.h' file containing system-dependent definitions.
-Finally, it creates a shell script named 'config.status' that you can
+those values to create a ‘Makefile’ in each directory of the package
+(the top directory, the ‘builtins’, ‘doc’, ‘po’, and ‘support’
+directories, each directory under ‘lib’, and several others). It also
+creates a ‘config.h’ file containing system-dependent definitions.
+Finally, it creates a shell script named ‘config.status’ that you can
run in the future to recreate the current configuration, a file
-'config.cache' that saves the results of its tests to speed up
-reconfiguring, and a file 'config.log' containing compiler output
-(useful mainly for debugging 'configure'). If at some point
-'config.cache' contains results you don't want to keep, you may remove
+‘config.cache’ that saves the results of its tests to speed up
+reconfiguring, and a file ‘config.log’ containing compiler output
+(useful mainly for debugging ‘configure’). If at some point
+‘config.cache’ contains results you don't want to keep, you may remove
or edit it.
- To find out more about the options and arguments that the 'configure'
+ To find out more about the options and arguments that the ‘configure’
script understands, type
bash-4.2$ ./configure --help
If you want to build Bash in a directory separate from the source
directory - to build for multiple architectures, for example - just use
the full path to the configure script. The following commands will
-build Bash in a directory under '/usr/local/build' from the source code
-in '/usr/local/src/bash-4.4':
+build Bash in a directory under ‘/usr/local/build’ from the source code
+in ‘/usr/local/src/bash-4.4’:
mkdir /usr/local/build/bash-4.4
cd /usr/local/build/bash-4.4
about building in a directory separate from the source.
If you need to do unusual things to compile Bash, please try to
-figure out how 'configure' could check whether or not to do them, and
+figure out how ‘configure’ could check whether or not to do them, and
mail diffs or instructions to <bash-maintainers@gnu.org> so they can be
considered for the next release.
- The file 'configure.ac' is used to create 'configure' by a program
-called Autoconf. You only need 'configure.ac' if you want to change it
-or regenerate 'configure' using a newer version of Autoconf. If you do
+ The file ‘configure.ac’ is used to create ‘configure’ by a program
+called Autoconf. You only need ‘configure.ac’ if you want to change it
+or regenerate ‘configure’ using a newer version of Autoconf. If you do
this, make sure you are using Autoconf version 2.69 or newer.
You can remove the program binaries and object files from the source
-code directory by typing 'make clean'. To also remove the files that
-'configure' created (so you can compile Bash for a different kind of
-computer), type 'make distclean'.
+code directory by typing ‘make clean’. To also remove the files that
+‘configure’ created (so you can compile Bash for a different kind of
+computer), type ‘make distclean’.
\1f
File: bash.info, Node: Compilers and Options, Next: Compiling For Multiple Architectures, Prev: Basic Installation, Up: Installing Bash
==========================
Some systems require unusual options for compilation or linking that the
-'configure' script does not know about. You can give 'configure'
+‘configure’ script does not know about. You can give ‘configure’
initial values for variables by setting them in the environment. Using
a Bourne-compatible shell, you can do that on the command line like
this:
CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure
- On systems that have the 'env' program, you can do it like this:
+ On systems that have the ‘env’ program, you can do it like this:
env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure
You can compile Bash for more than one kind of computer at the same
time, by placing the object files for each architecture in their own
-directory. To do this, you must use a version of 'make' that supports
-the 'VPATH' variable, such as GNU 'make'. 'cd' to the directory where
-you want the object files and executables to go and run the 'configure'
+directory. To do this, you must use a version of ‘make’ that supports
+the ‘VPATH’ variable, such as GNU ‘make’. ‘cd’ to the directory where
+you want the object files and executables to go and run the ‘configure’
script from the source directory (*note Basic Installation::). You may
-need to supply the '--srcdir=PATH' argument to tell 'configure' where
-the source files are. 'configure' automatically checks for the source
-code in the directory that 'configure' is in and in '..'.
+need to supply the ‘--srcdir=PATH’ argument to tell ‘configure’ where
+the source files are. ‘configure’ automatically checks for the source
+code in the directory that ‘configure’ is in and in '..'.
- If you have to use a 'make' that does not support the 'VPATH'
+ If you have to use a ‘make’ that does not support the ‘VPATH’
variable, you can compile Bash for one architecture at a time in the
source code directory. After you have installed Bash for one
-architecture, use 'make distclean' before reconfiguring for another
+architecture, use ‘make distclean’ before reconfiguring for another
architecture.
Alternatively, if your system supports symbolic links, you can use
-the 'support/mkclone' script to create a build tree which has symbolic
+the ‘support/mkclone’ script to create a build tree which has symbolic
links back to each file in the source directory. Here's an example that
creates a build directory in the current directory from a source
-directory '/usr/gnu/src/bash-2.0':
+directory ‘/usr/gnu/src/bash-2.0’:
bash /usr/gnu/src/bash-2.0/support/mkclone -s /usr/gnu/src/bash-2.0 .
-The 'mkclone' script requires Bash, so you must have already built Bash
+The ‘mkclone’ script requires Bash, so you must have already built Bash
for at least one architecture before you can create build directories
for other architectures.
10.4 Installation Names
=======================
-By default, 'make install' will install into '/usr/local/bin',
-'/usr/local/man', etc.; that is, the "installation prefix" defaults to
-'/usr/local'. You can specify an installation prefix other than
-'/usr/local' by giving 'configure' the option '--prefix=PATH', or by
-specifying a value for the 'prefix' 'make' variable when running 'make
-install' (e.g., 'make install prefix=PATH'). The 'prefix' variable
-provides a default for 'exec_prefix' and other variables used when
+By default, ‘make install’ will install into ‘/usr/local/bin’,
+‘/usr/local/man’, etc.; that is, the “installation prefix” defaults to
+‘/usr/local’. You can specify an installation prefix other than
+‘/usr/local’ by giving ‘configure’ the option ‘--prefix=PATH’, or by
+specifying a value for the ‘prefix’ ‘make’ variable when running ‘make
+install’ (e.g., ‘make install prefix=PATH’). The ‘prefix’ variable
+provides a default for ‘exec_prefix’ and other variables used when
installing Bash.
You can specify separate installation prefixes for
architecture-specific files and architecture-independent files. If you
-give 'configure' the option '--exec-prefix=PATH', 'make install' will
+give ‘configure’ the option ‘--exec-prefix=PATH’, ‘make install’ will
use PATH as the prefix for installing programs and libraries.
Documentation and other data files will still use the regular prefix.
If you would like to change the installation locations for a single
-run, you can specify these variables as arguments to 'make': 'make
-install exec_prefix=/' will install 'bash' and 'bashbug' into '/bin'
-instead of the default '/usr/local/bin'.
+run, you can specify these variables as arguments to ‘make’: ‘make
+install exec_prefix=/’ will install ‘bash’ and ‘bashbug’ into ‘/bin’
+instead of the default ‘/usr/local/bin’.
If you want to see the files Bash will install and where it will
install them without changing anything on your system, specify the
-variable 'DESTDIR' as an argument to 'make'. Its value should be the
+variable ‘DESTDIR’ as an argument to ‘make’. Its value should be the
absolute directory path you'd like to use as the root of your sample
installation tree. For example,
mkdir /fs1/bash-install
make install DESTDIR=/fs1/bash-install
-will install 'bash' into '/fs1/bash-install/usr/local/bin/bash', the
+will install ‘bash’ into ‘/fs1/bash-install/usr/local/bin/bash’, the
documentation into directories within
-'/fs1/bash-install/usr/local/share', the example loadable builtins into
-'/fs1/bash-install/usr/local/lib/bash', and so on. You can use the
-usual 'exec_prefix' and 'prefix' variables to alter the directory paths
-beneath the value of 'DESTDIR'.
+‘/fs1/bash-install/usr/local/share’, the example loadable builtins into
+‘/fs1/bash-install/usr/local/lib/bash’, and so on. You can use the
+usual ‘exec_prefix’ and ‘prefix’ variables to alter the directory paths
+beneath the value of ‘DESTDIR’.
The GNU Makefile standards provide a more complete description of
these variables and their effects.
10.5 Specifying the System Type
===============================
-There may be some features 'configure' can not figure out automatically,
+There may be some features ‘configure’ can not figure out automatically,
but needs to determine by the type of host Bash will run on. Usually
-'configure' can figure that out, but if it prints a message saying it
-can not guess the host type, give it the '--host=TYPE' option. 'TYPE'
-can either be a short name for the system type, such as 'sun4', or a
-canonical name with three fields: 'CPU-COMPANY-SYSTEM' (e.g.,
-'i386-unknown-freebsd4.2').
+‘configure’ can figure that out, but if it prints a message saying it
+can not guess the host type, give it the ‘--host=TYPE’ option. ‘TYPE’
+can either be a short name for the system type, such as ‘sun4’, or a
+canonical name with three fields: ‘CPU-COMPANY-SYSTEM’ (e.g.,
+‘i386-unknown-freebsd4.2’).
- See the file 'support/config.sub' for the possible values of each
+ See the file ‘support/config.sub’ for the possible values of each
field.
\1f
10.6 Sharing Defaults
=====================
-If you want to set default values for 'configure' scripts to share, you
-can create a site shell script called 'config.site' that gives default
-values for variables like 'CC', 'cache_file', and 'prefix'. 'configure'
-looks for 'PREFIX/share/config.site' if it exists, then
-'PREFIX/etc/config.site' if it exists. Or, you can set the
-'CONFIG_SITE' environment variable to the location of the site script.
-A warning: the Bash 'configure' looks for a site script, but not all
-'configure' scripts do.
+If you want to set default values for ‘configure’ scripts to share, you
+can create a site shell script called ‘config.site’ that gives default
+values for variables like ‘CC’, ‘cache_file’, and ‘prefix’. ‘configure’
+looks for ‘PREFIX/share/config.site’ if it exists, then
+‘PREFIX/etc/config.site’ if it exists. Or, you can set the
+‘CONFIG_SITE’ environment variable to the location of the site script.
+A warning: the Bash ‘configure’ looks for a site script, but not all
+‘configure’ scripts do.
\1f
File: bash.info, Node: Operation Controls, Next: Optional Features, Prev: Sharing Defaults, Up: Installing Bash
10.7 Operation Controls
=======================
-'configure' recognizes the following options to control how it operates.
+‘configure’ recognizes the following options to control how it operates.
-'--cache-file=FILE'
+‘--cache-file=FILE’
Use and save the results of the tests in FILE instead of
- './config.cache'. Set FILE to '/dev/null' to disable caching, for
- debugging 'configure'.
+ ‘./config.cache’. Set FILE to ‘/dev/null’ to disable caching, for
+ debugging ‘configure’.
-'--help'
- Print a summary of the options to 'configure', and exit.
+‘--help’
+ Print a summary of the options to ‘configure’, and exit.
-'--quiet'
-'--silent'
-'-q'
+‘--quiet’
+‘--silent’
+‘-q’
Do not print messages saying which checks are being made.
-'--srcdir=DIR'
+‘--srcdir=DIR’
Look for the Bash source code in directory DIR. Usually
- 'configure' can determine that directory automatically.
+ ‘configure’ can determine that directory automatically.
-'--version'
- Print the version of Autoconf used to generate the 'configure'
+‘--version’
+ Print the version of Autoconf used to generate the ‘configure’
script, and exit.
- 'configure' also accepts some other, not widely used, boilerplate
-options. 'configure --help' prints the complete list.
+ ‘configure’ also accepts some other, not widely used, boilerplate
+options. ‘configure --help’ prints the complete list.
\1f
File: bash.info, Node: Optional Features, Prev: Operation Controls, Up: Installing Bash
10.8 Optional Features
======================
-The Bash 'configure' has a number of '--enable-FEATURE' options, where
+The Bash ‘configure’ has a number of ‘--enable-FEATURE’ options, where
FEATURE indicates an optional part of Bash. There are also several
-'--with-PACKAGE' options, where PACKAGE is something like 'bash-malloc'
-or 'purify'. To turn off the default use of a package, use
-'--without-PACKAGE'. To configure Bash without a feature that is
-enabled by default, use '--disable-FEATURE'.
+‘--with-PACKAGE’ options, where PACKAGE is something like ‘bash-malloc’
+or ‘purify’. To turn off the default use of a package, use
+‘--without-PACKAGE’. To configure Bash without a feature that is
+enabled by default, use ‘--disable-FEATURE’.
- Here is a complete list of the '--enable-' and '--with-' options that
-the Bash 'configure' recognizes.
+ Here is a complete list of the ‘--enable-’ and ‘--with-’ options that
+the Bash ‘configure’ recognizes.
-'--with-afs'
+‘--with-afs’
Define if you are using the Andrew File System from Transarc.
-'--with-bash-malloc'
- Use the Bash version of 'malloc' in the directory 'lib/malloc'.
- This is not the same 'malloc' that appears in GNU libc, but an
- older version originally derived from the 4.2 BSD 'malloc'. This
- 'malloc' is very fast, but wastes some space on each allocation.
- This option is enabled by default. The 'NOTES' file contains a
+‘--with-bash-malloc’
+ Use the Bash version of ‘malloc’ in the directory ‘lib/malloc’.
+ This is not the same ‘malloc’ that appears in GNU libc, but an
+ older version originally derived from the 4.2 BSD ‘malloc’. This
+ ‘malloc’ is very fast, but wastes some space on each allocation.
+ This option is enabled by default. The ‘NOTES’ file contains a
list of systems for which this should be turned off, and
- 'configure' disables this option automatically for a number of
+ ‘configure’ disables this option automatically for a number of
systems.
-'--with-curses'
+‘--with-curses’
Use the curses library instead of the termcap library. This should
be supplied if your system has an inadequate or incomplete termcap
database.
-'--with-gnu-malloc'
- A synonym for '--with-bash-malloc'.
+‘--with-gnu-malloc’
+ A synonym for ‘--with-bash-malloc’.
-'--with-installed-readline[=PREFIX]'
+‘--with-installed-readline[=PREFIX]’
Define this to make Bash link with a locally-installed version of
- Readline rather than the version in 'lib/readline'. This works
- only with Readline 5.0 and later versions. If PREFIX is 'yes' or
- not supplied, 'configure' uses the values of the make variables
- 'includedir' and 'libdir', which are subdirectories of 'prefix' by
+ Readline rather than the version in ‘lib/readline’. This works
+ only with Readline 5.0 and later versions. If PREFIX is ‘yes’ or
+ not supplied, ‘configure’ uses the values of the make variables
+ ‘includedir’ and ‘libdir’, which are subdirectories of ‘prefix’ by
default, to find the installed version of Readline if it is not in
the standard system include and library directories. If PREFIX is
- 'no', Bash links with the version in 'lib/readline'. If PREFIX is
- set to any other value, 'configure' treats it as a directory
+ ‘no’, Bash links with the version in ‘lib/readline’. If PREFIX is
+ set to any other value, ‘configure’ treats it as a directory
pathname and looks for the installed version of Readline in
- subdirectories of that directory (include files in PREFIX/'include'
- and the library in PREFIX/'lib').
+ subdirectories of that directory (include files in PREFIX/‘include’
+ and the library in PREFIX/‘lib’).
-'--with-libintl-prefix[=PREFIX]'
+‘--with-libintl-prefix[=PREFIX]’
Define this to make Bash link with a locally-installed version of
- the libintl library instead of the version in 'lib/intl'.
+ the libintl library instead of the version in ‘lib/intl’.
-'--with-libiconv-prefix[=PREFIX]'
+‘--with-libiconv-prefix[=PREFIX]’
Define this to make Bash look for libiconv in PREFIX instead of the
standard system locations. There is no version included with Bash.
-'--enable-minimal-config'
+‘--enable-minimal-config’
This produces a shell with minimal features, close to the
historical Bourne shell.
- There are several '--enable-' options that alter how Bash is
+ There are several ‘--enable-’ options that alter how Bash is
compiled, linked, and installed, rather than changing run-time features.
-'--enable-largefile'
+‘--enable-largefile’
Enable support for large files
(http://www.unix.org/version2/whatsnew/lfs20mar.html) if the
operating system requires special compiler options to build
programs which can access large files. This is enabled by default,
if the operating system provides large file support.
-'--enable-profiling'
+‘--enable-profiling’
This builds a Bash binary that produces profiling information to be
- processed by 'gprof' each time it is executed.
+ processed by ‘gprof’ each time it is executed.
-'--enable-separate-helpfiles'
- Use external files for the documentation displayed by the 'help'
+‘--enable-separate-helpfiles’
+ Use external files for the documentation displayed by the ‘help’
builtin instead of storing the text internally.
-'--enable-static-link'
- This causes Bash to be linked statically, if 'gcc' is being used.
+‘--enable-static-link’
+ This causes Bash to be linked statically, if ‘gcc’ is being used.
This could be used to build a version to use as root's shell.
- The 'minimal-config' option can be used to disable all of the
+ The ‘minimal-config’ option can be used to disable all of the
following options, but it is processed first, so individual options may
-be enabled using 'enable-FEATURE'.
+be enabled using ‘enable-FEATURE’.
- All of the following options except for 'alt-array-implementation',
-'disabled-builtins', 'direxpand-default', 'strict-posix-default', and
-'xpg-echo-default' are enabled by default, unless the operating system
+ All of the following options except for ‘alt-array-implementation’,
+‘disabled-builtins’, ‘direxpand-default’, ‘strict-posix-default’, and
+‘xpg-echo-default’ are enabled by default, unless the operating system
does not provide the necessary support.
-'--enable-alias'
- Allow alias expansion and include the 'alias' and 'unalias'
+‘--enable-alias’
+ Allow alias expansion and include the ‘alias’ and ‘unalias’
builtins (*note Aliases::).
-'--enable-alt-array-implementation'
+‘--enable-alt-array-implementation’
This builds Bash using an alternate implementation of arrays (*note
Arrays::) that provides faster access at the expense of using more
memory (sometimes many times more, depending on how sparse an array
is).
-'--enable-arith-for-command'
- Include support for the alternate form of the 'for' command that
- behaves like the C language 'for' statement (*note Looping
+‘--enable-arith-for-command’
+ Include support for the alternate form of the ‘for’ command that
+ behaves like the C language ‘for’ statement (*note Looping
Constructs::).
-'--enable-array-variables'
+‘--enable-array-variables’
Include support for one-dimensional array shell variables (*note
Arrays::).
-'--enable-bang-history'
- Include support for 'csh'-like history substitution (*note History
+‘--enable-bang-history’
+ Include support for ‘csh’-like history substitution (*note History
Interaction::).
-'--enable-brace-expansion'
- Include 'csh'-like brace expansion ( 'b{a,b}c' ==> 'bac bbc' ).
- See *note Brace Expansion::, for a complete description.
+‘--enable-brace-expansion’
+ Include ‘csh’-like brace expansion ( ‘b{a,b}c’ ↦ ‘bac bbc’ ). See
+ *note Brace Expansion::, for a complete description.
-'--enable-casemod-attributes'
- Include support for case-modifying attributes in the 'declare'
- builtin and assignment statements. Variables with the 'uppercase'
+‘--enable-casemod-attributes’
+ Include support for case-modifying attributes in the ‘declare’
+ builtin and assignment statements. Variables with the ‘uppercase’
attribute, for example, will have their values converted to
uppercase upon assignment.
-'--enable-casemod-expansion'
+‘--enable-casemod-expansion’
Include support for case-modifying word expansions.
-'--enable-command-timing'
- Include support for recognizing 'time' as a reserved word and for
- displaying timing statistics for the pipeline following 'time'
+‘--enable-command-timing’
+ Include support for recognizing ‘time’ as a reserved word and for
+ displaying timing statistics for the pipeline following ‘time’
(*note Pipelines::). This allows pipelines as well as shell
builtins and functions to be timed.
-'--enable-cond-command'
- Include support for the '[[' conditional command. (*note
+‘--enable-cond-command’
+ Include support for the ‘[[’ conditional command. (*note
Conditional Constructs::).
-'--enable-cond-regexp'
+‘--enable-cond-regexp’
Include support for matching POSIX regular expressions using the
- '=~' binary operator in the '[[' conditional command. (*note
+ ‘=~’ binary operator in the ‘[[’ conditional command. (*note
Conditional Constructs::).
-'--enable-coprocesses'
- Include support for coprocesses and the 'coproc' reserved word
+‘--enable-coprocesses’
+ Include support for coprocesses and the ‘coproc’ reserved word
(*note Pipelines::).
-'--enable-debugger'
+‘--enable-debugger’
Include support for the Bash debugger (distributed separately).
-'--enable-dev-fd-stat-broken'
- If calling 'stat' on /dev/fd/N returns different results than
- calling 'fstat' on file descriptor N, supply this option to enable
+‘--enable-dev-fd-stat-broken’
+ If calling ‘stat’ on /dev/fd/N returns different results than
+ calling ‘fstat’ on file descriptor N, supply this option to enable
a workaround. This has implications for conditional commands that
test file attributes.
-'--enable-direxpand-default'
- Cause the 'direxpand' shell option (*note The Shopt Builtin::) to
+‘--enable-direxpand-default’
+ Cause the ‘direxpand’ shell option (*note The Shopt Builtin::) to
be enabled by default when the shell starts. It is normally
disabled by default.
-'--enable-directory-stack'
- Include support for a 'csh'-like directory stack and the 'pushd',
- 'popd', and 'dirs' builtins (*note The Directory Stack::).
+‘--enable-directory-stack’
+ Include support for a ‘csh’-like directory stack and the ‘pushd’,
+ ‘popd’, and ‘dirs’ builtins (*note The Directory Stack::).
-'--enable-disabled-builtins'
- Allow builtin commands to be invoked via 'builtin xxx' even after
- 'xxx' has been disabled using 'enable -n xxx'. See *note Bash
- Builtins::, for details of the 'builtin' and 'enable' builtin
+‘--enable-disabled-builtins’
+ Allow builtin commands to be invoked via ‘builtin xxx’ even after
+ ‘xxx’ has been disabled using ‘enable -n xxx’. See *note Bash
+ Builtins::, for details of the ‘builtin’ and ‘enable’ builtin
commands.
-'--enable-dparen-arithmetic'
- Include support for the '((...))' command (*note Conditional
+‘--enable-dparen-arithmetic’
+ Include support for the ‘((...))’ command (*note Conditional
Constructs::).
-'--enable-extended-glob'
+‘--enable-extended-glob’
Include support for the extended pattern matching features
described above under *note Pattern Matching::.
-'--enable-extended-glob-default'
- Set the default value of the 'extglob' shell option described above
+‘--enable-extended-glob-default’
+ Set the default value of the ‘extglob’ shell option described above
under *note The Shopt Builtin:: to be enabled.
-'--enable-function-import'
+‘--enable-function-import’
Include support for importing function definitions exported by
another instance of the shell from the environment. This option is
enabled by default.
-'--enable-glob-asciiranges-default'
- Set the default value of the 'globasciiranges' shell option
+‘--enable-glob-asciiranges-default’
+ Set the default value of the ‘globasciiranges’ shell option
described above under *note The Shopt Builtin:: to be enabled.
This controls the behavior of character ranges when used in pattern
matching bracket expressions.
-'--enable-help-builtin'
- Include the 'help' builtin, which displays help on shell builtins
+‘--enable-help-builtin’
+ Include the ‘help’ builtin, which displays help on shell builtins
and variables (*note Bash Builtins::).
-'--enable-history'
- Include command history and the 'fc' and 'history' builtin commands
+‘--enable-history’
+ Include command history and the ‘fc’ and ‘history’ builtin commands
(*note Bash History Facilities::).
-'--enable-job-control'
+‘--enable-job-control’
This enables the job control features (*note Job Control::), if the
operating system supports them.
-'--enable-multibyte'
+‘--enable-multibyte’
This enables support for multibyte characters if the operating
system provides the necessary support.
-'--enable-net-redirections'
+‘--enable-net-redirections’
This enables the special handling of filenames of the form
- '/dev/tcp/HOST/PORT' and '/dev/udp/HOST/PORT' when used in
+ ‘/dev/tcp/HOST/PORT’ and ‘/dev/udp/HOST/PORT’ when used in
redirections (*note Redirections::).
-'--enable-process-substitution'
+‘--enable-process-substitution’
This enables process substitution (*note Process Substitution::) if
the operating system provides the necessary support.
-'--enable-progcomp'
+‘--enable-progcomp’
Enable the programmable completion facilities (*note Programmable
Completion::). If Readline is not enabled, this option has no
effect.
-'--enable-prompt-string-decoding'
+‘--enable-prompt-string-decoding’
Turn on the interpretation of a number of backslash-escaped
- characters in the '$PS0', '$PS1', '$PS2', and '$PS4' prompt
+ characters in the ‘$PS0’, ‘$PS1’, ‘$PS2’, and ‘$PS4’ prompt
strings. See *note Controlling the Prompt::, for a complete list
of prompt string escape sequences.
-'--enable-readline'
+‘--enable-readline’
Include support for command-line editing and history with the Bash
version of the Readline library (*note Command Line Editing::).
-'--enable-restricted'
- Include support for a "restricted shell". If this is enabled,
- Bash, when called as 'rbash', enters a restricted mode. See *note
+‘--enable-restricted’
+ Include support for a “restricted shell”. If this is enabled,
+ Bash, when called as ‘rbash’, enters a restricted mode. See *note
The Restricted Shell::, for a description of restricted mode.
-'--enable-select'
- Include the 'select' compound command, which allows the generation
+‘--enable-select’
+ Include the ‘select’ compound command, which allows the generation
of simple menus (*note Conditional Constructs::).
-'--enable-single-help-strings'
- Store the text displayed by the 'help' builtin as a single string
+‘--enable-single-help-strings’
+ Store the text displayed by the ‘help’ builtin as a single string
for each help topic. This aids in translating the text to
different languages. You may need to disable this if your compiler
cannot handle very long string literals.
-'--enable-strict-posix-default'
+‘--enable-strict-posix-default’
Make Bash POSIX-conformant by default (*note Bash POSIX Mode::).
-'--enable-translatable-strings'
- Enable support for '$"STRING"' translatable strings (*note Locale
+‘--enable-translatable-strings’
+ Enable support for ‘$"STRING"’ translatable strings (*note Locale
Translation::).
-'--enable-usg-echo-default'
- A synonym for '--enable-xpg-echo-default'.
+‘--enable-usg-echo-default’
+ A synonym for ‘--enable-xpg-echo-default’.
-'--enable-xpg-echo-default'
- Make the 'echo' builtin expand backslash-escaped characters by
- default, without requiring the '-e' option. This sets the default
- value of the 'xpg_echo' shell option to 'on', which makes the Bash
- 'echo' behave more like the version specified in the Single Unix
+‘--enable-xpg-echo-default’
+ Make the ‘echo’ builtin expand backslash-escaped characters by
+ default, without requiring the ‘-e’ option. This sets the default
+ value of the ‘xpg_echo’ shell option to ‘on’, which makes the Bash
+ ‘echo’ behave more like the version specified in the Single Unix
Specification, version 3. *Note Bash Builtins::, for a description
- of the escape sequences that 'echo' recognizes.
+ of the escape sequences that ‘echo’ recognizes.
- The file 'config-top.h' contains C Preprocessor '#define' statements
-for options which are not settable from 'configure'. Some of these are
+ The file ‘config-top.h’ contains C Preprocessor ‘#define’ statements
+for options which are not settable from ‘configure’. Some of these are
not meant to be changed; beware of the consequences if you do. Read the
comments associated with each definition for more information about its
effect.
<http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-master.tar.gz>.
Once you have determined that a bug actually exists, use the
-'bashbug' command to submit a bug report or use the form at the Bash
+‘bashbug’ command to submit a bug report or use the form at the Bash
project page (https://savannah.gnu.org/projects/bash/). If you have a
fix, you are encouraged to submit that as well! Suggestions and
'philosophical' bug reports may be mailed to <bug-bash@gnu.org> or
<help-bash@gnu.org>.
All bug reports should include:
- * The version number of Bash.
- * The hardware and operating system.
- * The compiler used to compile Bash.
- * A description of the bug behaviour.
- * A short script or 'recipe' which exercises the bug and may be used
+ • The version number of Bash.
+ • The hardware and operating system.
+ • The compiler used to compile Bash.
+ • A description of the bug behaviour.
+ • A short script or 'recipe' which exercises the bug and may be used
to reproduce it.
-'bashbug' inserts the first three items automatically into the template
+‘bashbug’ inserts the first three items automatically into the template
it provides for filing a bug report.
Please send all reports concerning this manual to <bug-bash@gnu.org>.
implemented. There are some differences between the traditional Bourne
shell and Bash; this section quickly details the differences of
significance. A number of these differences are explained in greater
-depth in previous sections. This section uses the version of 'sh'
+depth in previous sections. This section uses the version of ‘sh’
included in SVR4.2 (the last version of the historical Bourne shell) as
the baseline reference.
- * Bash is POSIX-conformant, even where the POSIX specification
- differs from traditional 'sh' behavior (*note Bash POSIX Mode::).
+ • Bash is POSIX-conformant, even where the POSIX specification
+ differs from traditional ‘sh’ behavior (*note Bash POSIX Mode::).
- * Bash has multi-character invocation options (*note Invoking
+ • Bash has multi-character invocation options (*note Invoking
Bash::).
- * Bash has command-line editing (*note Command Line Editing::) and
- the 'bind' builtin.
+ • Bash has command-line editing (*note Command Line Editing::) and
+ the ‘bind’ builtin.
- * Bash provides a programmable word completion mechanism (*note
- Programmable Completion::), and builtin commands 'complete',
- 'compgen', and 'compopt', to manipulate it.
+ • Bash provides a programmable word completion mechanism (*note
+ Programmable Completion::), and builtin commands ‘complete’,
+ ‘compgen’, and ‘compopt’, to manipulate it.
- * Bash has command history (*note Bash History Facilities::) and the
- 'history' and 'fc' builtins to manipulate it. The Bash history
+ • Bash has command history (*note Bash History Facilities::) and the
+ ‘history’ and ‘fc’ builtins to manipulate it. The Bash history
list maintains timestamp information and uses the value of the
- 'HISTTIMEFORMAT' variable to display it.
+ ‘HISTTIMEFORMAT’ variable to display it.
- * Bash implements 'csh'-like history expansion (*note History
+ • Bash implements ‘csh’-like history expansion (*note History
Interaction::).
- * Bash has one-dimensional array variables (*note Arrays::), and the
+ • Bash has one-dimensional array variables (*note Arrays::), and the
appropriate variable expansions and assignment syntax to use them.
Several of the Bash builtins take options to act on arrays. Bash
provides a number of built-in array variables.
- * The '$'...'' quoting syntax, which expands ANSI-C backslash-escaped
+ • The ‘$'...'’ quoting syntax, which expands ANSI-C backslash-escaped
characters in the text between the single quotes, is supported
(*note ANSI-C Quoting::).
- * Bash supports the '$"..."' quoting syntax to do locale-specific
- translation of the characters between the double quotes. The '-D',
- '--dump-strings', and '--dump-po-strings' invocation options list
+ • Bash supports the ‘$"..."’ quoting syntax to do locale-specific
+ translation of the characters between the double quotes. The ‘-D’,
+ ‘--dump-strings’, and ‘--dump-po-strings’ invocation options list
the translatable strings found in a script (*note Locale
Translation::).
- * Bash implements the '!' keyword to negate the return value of a
- pipeline (*note Pipelines::). Very useful when an 'if' statement
- needs to act only if a test fails. The Bash '-o pipefail' option
- to 'set' will cause a pipeline to return a failure status if any
+ • Bash implements the ‘!’ keyword to negate the return value of a
+ pipeline (*note Pipelines::). Very useful when an ‘if’ statement
+ needs to act only if a test fails. The Bash ‘-o pipefail’ option
+ to ‘set’ will cause a pipeline to return a failure status if any
command fails.
- * Bash has the 'time' reserved word and command timing (*note
+ • Bash has the ‘time’ reserved word and command timing (*note
Pipelines::). The display of the timing statistics may be
- controlled with the 'TIMEFORMAT' variable.
+ controlled with the ‘TIMEFORMAT’ variable.
- * Bash implements the 'for (( EXPR1 ; EXPR2 ; EXPR3 ))' arithmetic
+ • Bash implements the ‘for (( EXPR1 ; EXPR2 ; EXPR3 ))’ arithmetic
for command, similar to the C language (*note Looping
Constructs::).
- * Bash includes the 'select' compound command, which allows the
+ • Bash includes the ‘select’ compound command, which allows the
generation of simple menus (*note Conditional Constructs::).
- * Bash includes the '[[' compound command, which makes conditional
+ • Bash includes the ‘[[’ compound command, which makes conditional
testing part of the shell grammar (*note Conditional Constructs::),
including optional regular expression matching.
- * Bash provides optional case-insensitive matching for the 'case' and
- '[[' constructs.
+ • Bash provides optional case-insensitive matching for the ‘case’ and
+ ‘[[’ constructs.
- * Bash includes brace expansion (*note Brace Expansion::) and tilde
+ • Bash includes brace expansion (*note Brace Expansion::) and tilde
expansion (*note Tilde Expansion::).
- * Bash implements command aliases and the 'alias' and 'unalias'
+ • Bash implements command aliases and the ‘alias’ and ‘unalias’
builtins (*note Aliases::).
- * Bash provides shell arithmetic, the '((' compound command (*note
+ • Bash provides shell arithmetic, the ‘((’ compound command (*note
Conditional Constructs::), and arithmetic expansion (*note Shell
Arithmetic::).
- * Variables present in the shell's initial environment are
+ • Variables present in the shell's initial environment are
automatically exported to child processes. The Bourne shell does
not normally do this unless the variables are explicitly marked
- using the 'export' command.
+ using the ‘export’ command.
- * Bash supports the '+=' assignment operator, which appends to the
+ • Bash supports the ‘+=’ assignment operator, which appends to the
value of the variable named on the left hand side.
- * Bash includes the POSIX pattern removal '%', '#', '%%' and '##'
+ • Bash includes the POSIX pattern removal ‘%’, ‘#’, ‘%%’ and ‘##’
expansions to remove leading or trailing substrings from variable
values (*note Shell Parameter Expansion::).
- * The expansion '${#xx}', which returns the length of '${xx}', is
+ • The expansion ‘${#xx}’, which returns the length of ‘${xx}’, is
supported (*note Shell Parameter Expansion::).
- * The expansion '${var:'OFFSET'[:'LENGTH']}', which expands to the
- substring of 'var''s value of length LENGTH, beginning at OFFSET,
+ • The expansion ‘${var:’OFFSET‘[:’LENGTH‘]}’, which expands to the
+ substring of ‘var’'s value of length LENGTH, beginning at OFFSET,
is present (*note Shell Parameter Expansion::).
- * The expansion '${VAR/[/]'PATTERN'[/'REPLACEMENT']}', which matches
+ • The expansion ‘${VAR/[/]’PATTERN‘[/’REPLACEMENT‘]}’, which matches
PATTERN and replaces it with REPLACEMENT in the value of VAR, is
available (*note Shell Parameter Expansion::).
- * The expansion '${!PREFIX*}' expansion, which expands to the names
+ • The expansion ‘${!PREFIX*}’ expansion, which expands to the names
of all shell variables whose names begin with PREFIX, is available
(*note Shell Parameter Expansion::).
- * Bash has indirect variable expansion using '${!word}' (*note Shell
+ • Bash has indirect variable expansion using ‘${!word}’ (*note Shell
Parameter Expansion::).
- * Bash can expand positional parameters beyond '$9' using '${NUM}'.
+ • Bash can expand positional parameters beyond ‘$9’ using ‘${NUM}’.
- * The POSIX '$()' form of command substitution is implemented (*note
- Command Substitution::), and preferred to the Bourne shell's '``'
+ • The POSIX ‘$()’ form of command substitution is implemented (*note
+ Command Substitution::), and preferred to the Bourne shell's ‘``’
(which is also implemented for backwards compatibility).
- * Bash has process substitution (*note Process Substitution::).
+ • Bash has process substitution (*note Process Substitution::).
- * Bash automatically assigns variables that provide information about
- the current user ('UID', 'EUID', and 'GROUPS'), the current host
- ('HOSTTYPE', 'OSTYPE', 'MACHTYPE', and 'HOSTNAME'), and the
- instance of Bash that is running ('BASH', 'BASH_VERSION', and
- 'BASH_VERSINFO'). *Note Bash Variables::, for details.
+ • Bash automatically assigns variables that provide information about
+ the current user (‘UID’, ‘EUID’, and ‘GROUPS’), the current host
+ (‘HOSTTYPE’, ‘OSTYPE’, ‘MACHTYPE’, and ‘HOSTNAME’), and the
+ instance of Bash that is running (‘BASH’, ‘BASH_VERSION’, and
+ ‘BASH_VERSINFO’). *Note Bash Variables::, for details.
- * The 'IFS' variable is used to split only the results of expansion,
+ • The ‘IFS’ variable is used to split only the results of expansion,
not all words (*note Word Splitting::). This closes a longstanding
shell security hole.
- * The filename expansion bracket expression code uses '!' and '^' to
+ • The filename expansion bracket expression code uses ‘!’ and ‘^’ to
negate the set of characters between the brackets. The Bourne
- shell uses only '!'.
+ shell uses only ‘!’.
- * Bash implements the full set of POSIX filename expansion operators,
+ • Bash implements the full set of POSIX filename expansion operators,
including character classes, equivalence classes, and collating
symbols (*note Filename Expansion::).
- * Bash implements extended pattern matching features when the
- 'extglob' shell option is enabled (*note Pattern Matching::).
+ • Bash implements extended pattern matching features when the
+ ‘extglob’ shell option is enabled (*note Pattern Matching::).
- * It is possible to have a variable and a function with the same
- name; 'sh' does not separate the two name spaces.
+ • It is possible to have a variable and a function with the same
+ name; ‘sh’ does not separate the two name spaces.
- * Bash functions are permitted to have local variables using the
- 'local' builtin, and thus useful recursive functions may be written
+ • Bash functions are permitted to have local variables using the
+ ‘local’ builtin, and thus useful recursive functions may be written
(*note Bash Builtins::).
- * Variable assignments preceding commands affect only that command,
- even builtins and functions (*note Environment::). In 'sh', all
+ • Variable assignments preceding commands affect only that command,
+ even builtins and functions (*note Environment::). In ‘sh’, all
variable assignments preceding commands are global unless the
command is executed from the file system.
- * Bash performs filename expansion on filenames specified as operands
+ • Bash performs filename expansion on filenames specified as operands
to input and output redirection operators (*note Redirections::).
- * Bash contains the '<>' redirection operator, allowing a file to be
- opened for both reading and writing, and the '&>' redirection
+ • Bash contains the ‘<>’ redirection operator, allowing a file to be
+ opened for both reading and writing, and the ‘&>’ redirection
operator, for directing standard output and standard error to the
same file (*note Redirections::).
- * Bash includes the '<<<' redirection operator, allowing a string to
+ • Bash includes the ‘<<<’ redirection operator, allowing a string to
be used as the standard input to a command.
- * Bash implements the '[n]<&WORD' and '[n]>&WORD' redirection
+ • Bash implements the ‘[n]<&WORD’ and ‘[n]>&WORD’ redirection
operators, which move one file descriptor to another.
- * Bash treats a number of filenames specially when they are used in
+ • Bash treats a number of filenames specially when they are used in
redirection operators (*note Redirections::).
- * Bash can open network connections to arbitrary machines and
+ • Bash can open network connections to arbitrary machines and
services with the redirection operators (*note Redirections::).
- * The 'noclobber' option is available to avoid overwriting existing
- files with output redirection (*note The Set Builtin::). The '>|'
- redirection operator may be used to override 'noclobber'.
+ • The ‘noclobber’ option is available to avoid overwriting existing
+ files with output redirection (*note The Set Builtin::). The ‘>|’
+ redirection operator may be used to override ‘noclobber’.
- * The Bash 'cd' and 'pwd' builtins (*note Bourne Shell Builtins::)
- each take '-L' and '-P' options to switch between logical and
+ • The Bash ‘cd’ and ‘pwd’ builtins (*note Bourne Shell Builtins::)
+ each take ‘-L’ and ‘-P’ options to switch between logical and
physical modes.
- * Bash allows a function to override a builtin with the same name,
+ • Bash allows a function to override a builtin with the same name,
and provides access to that builtin's functionality within the
- function via the 'builtin' and 'command' builtins (*note Bash
+ function via the ‘builtin’ and ‘command’ builtins (*note Bash
Builtins::).
- * The 'command' builtin allows selective disabling of functions when
+ • The ‘command’ builtin allows selective disabling of functions when
command lookup is performed (*note Bash Builtins::).
- * Individual builtins may be enabled or disabled using the 'enable'
+ • Individual builtins may be enabled or disabled using the ‘enable’
builtin (*note Bash Builtins::).
- * The Bash 'exec' builtin takes additional options that allow users
+ • The Bash ‘exec’ builtin takes additional options that allow users
to control the contents of the environment passed to the executed
command, and what the zeroth argument to the command is to be
(*note Bourne Shell Builtins::).
- * Shell functions may be exported to children via the environment
- using 'export -f' (*note Shell Functions::).
+ • Shell functions may be exported to children via the environment
+ using ‘export -f’ (*note Shell Functions::).
- * The Bash 'export', 'readonly', and 'declare' builtins can take a
- '-f' option to act on shell functions, a '-p' option to display
+ • The Bash ‘export’, ‘readonly’, and ‘declare’ builtins can take a
+ ‘-f’ option to act on shell functions, a ‘-p’ option to display
variables with various attributes set in a format that can be used
- as shell input, a '-n' option to remove various variable
- attributes, and 'name=value' arguments to set variable attributes
+ as shell input, a ‘-n’ option to remove various variable
+ attributes, and ‘name=value’ arguments to set variable attributes
and values simultaneously.
- * The Bash 'hash' builtin allows a name to be associated with an
+ • The Bash ‘hash’ builtin allows a name to be associated with an
arbitrary filename, even when that filename cannot be found by
- searching the '$PATH', using 'hash -p' (*note Bourne Shell
+ searching the ‘$PATH’, using ‘hash -p’ (*note Bourne Shell
Builtins::).
- * Bash includes a 'help' builtin for quick reference to shell
+ • Bash includes a ‘help’ builtin for quick reference to shell
facilities (*note Bash Builtins::).
- * The 'printf' builtin is available to display formatted output
+ • The ‘printf’ builtin is available to display formatted output
(*note Bash Builtins::).
- * The Bash 'read' builtin (*note Bash Builtins::) will read a line
- ending in '\' with the '-r' option, and will use the 'REPLY'
+ • The Bash ‘read’ builtin (*note Bash Builtins::) will read a line
+ ending in ‘\’ with the ‘-r’ option, and will use the ‘REPLY’
variable as a default if no non-option arguments are supplied. The
- Bash 'read' builtin also accepts a prompt string with the '-p'
- option and will use Readline to obtain the line when given the '-e'
- or '-E' options. The 'read' builtin also has additional options to
- control input: the '-s' option will turn off echoing of input
- characters as they are read, the '-t' option will allow 'read' to
+ Bash ‘read’ builtin also accepts a prompt string with the ‘-p’
+ option and will use Readline to obtain the line when given the ‘-e’
+ or ‘-E’ options. The ‘read’ builtin also has additional options to
+ control input: the ‘-s’ option will turn off echoing of input
+ characters as they are read, the ‘-t’ option will allow ‘read’ to
time out if input does not arrive within a specified number of
- seconds, the '-n' option will allow reading only a specified number
- of characters rather than a full line, and the '-d' option will
+ seconds, the ‘-n’ option will allow reading only a specified number
+ of characters rather than a full line, and the ‘-d’ option will
read until a particular character rather than newline.
- * The 'return' builtin may be used to abort execution of scripts
- executed with the '.' or 'source' builtins (*note Bourne Shell
+ • The ‘return’ builtin may be used to abort execution of scripts
+ executed with the ‘.’ or ‘source’ builtins (*note Bourne Shell
Builtins::).
- * Bash includes the 'shopt' builtin, for finer control of shell
+ • Bash includes the ‘shopt’ builtin, for finer control of shell
optional capabilities (*note The Shopt Builtin::), and allows these
options to be set and unset at shell invocation (*note Invoking
Bash::).
- * Bash has much more optional behavior controllable with the 'set'
+ • Bash has much more optional behavior controllable with the ‘set’
builtin (*note The Set Builtin::).
- * The '-x' ('xtrace') option displays commands other than simple
+ • The ‘-x’ (‘xtrace’) option displays commands other than simple
commands when performing an execution trace (*note The Set
Builtin::).
- * The 'test' builtin (*note Bourne Shell Builtins::) is slightly
+ • The ‘test’ builtin (*note Bourne Shell Builtins::) is slightly
different, as it implements the POSIX algorithm, which specifies
the behavior based on the number of arguments.
- * Bash includes the 'caller' builtin, which displays the context of
+ • Bash includes the ‘caller’ builtin, which displays the context of
any active subroutine call (a shell function or a script executed
- with the '.' or 'source' builtins). This supports the Bash
+ with the ‘.’ or ‘source’ builtins). This supports the Bash
debugger.
- * The 'trap' builtin (*note Bourne Shell Builtins::) allows a 'DEBUG'
- pseudo-signal specification, similar to 'EXIT'. Commands specified
- with a 'DEBUG' trap are executed before every simple command, 'for'
- command, 'case' command, 'select' command, every arithmetic 'for'
+ • The ‘trap’ builtin (*note Bourne Shell Builtins::) allows a ‘DEBUG’
+ pseudo-signal specification, similar to ‘EXIT’. Commands specified
+ with a ‘DEBUG’ trap are executed before every simple command, ‘for’
+ command, ‘case’ command, ‘select’ command, every arithmetic ‘for’
command, and before the first command executes in a shell function.
- The 'DEBUG' trap is not inherited by shell functions unless the
- function has been given the 'trace' attribute or the 'functrace'
- option has been enabled using the 'shopt' builtin. The 'extdebug'
- shell option has additional effects on the 'DEBUG' trap.
-
- The 'trap' builtin (*note Bourne Shell Builtins::) allows an 'ERR'
- pseudo-signal specification, similar to 'EXIT' and 'DEBUG'.
- Commands specified with an 'ERR' trap are executed after a simple
- command fails, with a few exceptions. The 'ERR' trap is not
- inherited by shell functions unless the '-o errtrace' option to the
- 'set' builtin is enabled.
-
- The 'trap' builtin (*note Bourne Shell Builtins::) allows a
- 'RETURN' pseudo-signal specification, similar to 'EXIT' and
- 'DEBUG'. Commands specified with a 'RETURN' trap are executed
+ The ‘DEBUG’ trap is not inherited by shell functions unless the
+ function has been given the ‘trace’ attribute or the ‘functrace’
+ option has been enabled using the ‘shopt’ builtin. The ‘extdebug’
+ shell option has additional effects on the ‘DEBUG’ trap.
+
+ The ‘trap’ builtin (*note Bourne Shell Builtins::) allows an ‘ERR’
+ pseudo-signal specification, similar to ‘EXIT’ and ‘DEBUG’.
+ Commands specified with an ‘ERR’ trap are executed after a simple
+ command fails, with a few exceptions. The ‘ERR’ trap is not
+ inherited by shell functions unless the ‘-o errtrace’ option to the
+ ‘set’ builtin is enabled.
+
+ The ‘trap’ builtin (*note Bourne Shell Builtins::) allows a
+ ‘RETURN’ pseudo-signal specification, similar to ‘EXIT’ and
+ ‘DEBUG’. Commands specified with a ‘RETURN’ trap are executed
before execution resumes after a shell function or a shell script
- executed with '.' or 'source' returns. The 'RETURN' trap is not
+ executed with ‘.’ or ‘source’ returns. The ‘RETURN’ trap is not
inherited by shell functions unless the function has been given the
- 'trace' attribute or the 'functrace' option has been enabled using
- the 'shopt' builtin.
+ ‘trace’ attribute or the ‘functrace’ option has been enabled using
+ the ‘shopt’ builtin.
- * The Bash 'type' builtin is more extensive and gives more
+ • The Bash ‘type’ builtin is more extensive and gives more
information about the names it finds (*note Bash Builtins::).
- * The Bash 'umask' builtin permits a '-p' option to cause the output
- to be displayed in the form of a 'umask' command that may be reused
+ • The Bash ‘umask’ builtin permits a ‘-p’ option to cause the output
+ to be displayed in the form of a ‘umask’ command that may be reused
as input (*note Bourne Shell Builtins::).
- * Bash implements a 'csh'-like directory stack, and provides the
- 'pushd', 'popd', and 'dirs' builtins to manipulate it (*note The
+ • Bash implements a ‘csh’-like directory stack, and provides the
+ ‘pushd’, ‘popd’, and ‘dirs’ builtins to manipulate it (*note The
Directory Stack::). Bash also makes the directory stack visible as
- the value of the 'DIRSTACK' shell variable.
+ the value of the ‘DIRSTACK’ shell variable.
- * Bash interprets special backslash-escaped characters in the prompt
+ • Bash interprets special backslash-escaped characters in the prompt
strings when interactive (*note Controlling the Prompt::).
- * The Bash restricted mode is more useful (*note The Restricted
+ • The Bash restricted mode is more useful (*note The Restricted
Shell::); the SVR4.2 shell restricted mode is too limited.
- * The 'disown' builtin can remove a job from the internal shell job
+ • The ‘disown’ builtin can remove a job from the internal shell job
table (*note Job Control Builtins::) or suppress the sending of
- 'SIGHUP' to a job when the shell exits as the result of a 'SIGHUP'.
+ ‘SIGHUP’ to a job when the shell exits as the result of a ‘SIGHUP’.
- * Bash includes a number of features to support a separate debugger
+ • Bash includes a number of features to support a separate debugger
for shell scripts.
- * The SVR4.2 shell has two privilege-related builtins ('mldmode' and
- 'priv') not present in Bash.
+ • The SVR4.2 shell has two privilege-related builtins (‘mldmode’ and
+ ‘priv’) not present in Bash.
- * Bash does not have the 'stop' or 'newgrp' builtins.
+ • Bash does not have the ‘stop’ or ‘newgrp’ builtins.
- * Bash does not use the 'SHACCT' variable or perform shell
+ • Bash does not use the ‘SHACCT’ variable or perform shell
accounting.
- * The SVR4.2 'sh' uses a 'TIMEOUT' variable like Bash uses 'TMOUT'.
+ • The SVR4.2 ‘sh’ uses a ‘TIMEOUT’ variable like Bash uses ‘TMOUT’.
More features unique to Bash may be found in *note Bash Features::.
Since Bash is a completely new implementation, it does not suffer from
many of the limitations of the SVR4.2 shell. For instance:
- * Bash does not fork a subshell when redirecting into or out of a
- shell control structure such as an 'if' or 'while' statement.
+ • Bash does not fork a subshell when redirecting into or out of a
+ shell control structure such as an ‘if’ or ‘while’ statement.
- * Bash does not allow unbalanced quotes. The SVR4.2 shell will
- silently insert a needed closing quote at 'EOF' under certain
+ • Bash does not allow unbalanced quotes. The SVR4.2 shell will
+ silently insert a needed closing quote at ‘EOF’ under certain
circumstances. This can be the cause of some hard-to-find errors.
- * The SVR4.2 shell uses a baroque memory management scheme based on
- trapping 'SIGSEGV'. If the shell is started from a process with
- 'SIGSEGV' blocked (e.g., by using the 'system()' C library function
+ • The SVR4.2 shell uses a baroque memory management scheme based on
+ trapping ‘SIGSEGV’. If the shell is started from a process with
+ ‘SIGSEGV’ blocked (e.g., by using the ‘system()’ C library function
call), it misbehaves badly.
- * In a questionable attempt at security, the SVR4.2 shell, when
- invoked without the '-p' option, will alter its real and effective
+ • In a questionable attempt at security, the SVR4.2 shell, when
+ invoked without the ‘-p’ option, will alter its real and effective
UID and GID if they are less than some magic threshold value,
commonly 100. This can lead to unexpected results.
- * The SVR4.2 shell does not allow users to trap 'SIGSEGV', 'SIGALRM',
- or 'SIGCHLD'.
+ • The SVR4.2 shell does not allow users to trap ‘SIGSEGV’, ‘SIGALRM’,
+ or ‘SIGCHLD’.
- * The SVR4.2 shell does not allow the 'IFS', 'MAILCHECK', 'PATH',
- 'PS1', or 'PS2' variables to be unset.
+ • The SVR4.2 shell does not allow the ‘IFS’, ‘MAILCHECK’, ‘PATH’,
+ ‘PS1’, or ‘PS2’ variables to be unset.
- * The SVR4.2 shell treats '^' as the undocumented equivalent of '|'.
+ • The SVR4.2 shell treats ‘^’ as the undocumented equivalent of ‘|’.
- * Bash allows multiple option arguments when it is invoked ('-x -v');
- the SVR4.2 shell allows only one option argument ('-xv'). In fact,
+ • Bash allows multiple option arguments when it is invoked (‘-x -v’);
+ the SVR4.2 shell allows only one option argument (‘-xv’). In fact,
some versions of the shell dump core if the second argument begins
- with a '-'.
+ with a ‘-’.
- * The SVR4.2 shell exits a script if any builtin fails; Bash exits a
+ • The SVR4.2 shell exits a script if any builtin fails; Bash exits a
script only if one of the POSIX special builtins fails, and only
for certain failures, as enumerated in the POSIX standard.
- * The SVR4.2 shell behaves differently when invoked as 'jsh' (it
+ • The SVR4.2 shell behaves differently when invoked as ‘jsh’ (it
turns on job control).
\1f
Version 1.3, 3 November 2008
- Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
+ Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
<http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
- functional and useful document "free" in the sense of freedom: to
+ functional and useful document “free” in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
\0\b[index\0\b]
* Menu:
-* .: Bourne Shell Builtins.
- (line 17)
* :: Bourne Shell Builtins.
(line 11)
+* .: Bourne Shell Builtins.
+ (line 17)
* [: Bourne Shell Builtins.
(line 285)
* alias: Bash Builtins. (line 11)
* pwd: Bourne Shell Builtins.
(line 222)
* read: Bash Builtins. (line 518)
-* readarray: Bash Builtins. (line 621)
+* readarray: Bash Builtins. (line 624)
* readonly: Bourne Shell Builtins.
(line 232)
* return: Bourne Shell Builtins.
* shift: Bourne Shell Builtins.
(line 272)
* shopt: The Shopt Builtin. (line 9)
-* source: Bash Builtins. (line 630)
+* source: Bash Builtins. (line 633)
* suspend: Job Control Builtins.
(line 116)
* test: Bourne Shell Builtins.
(line 393)
* true: Bourne Shell Builtins.
(line 455)
-* type: Bash Builtins. (line 635)
-* typeset: Bash Builtins. (line 673)
-* ulimit: Bash Builtins. (line 679)
+* type: Bash Builtins. (line 638)
+* typeset: Bash Builtins. (line 676)
+* ulimit: Bash Builtins. (line 682)
* umask: Bourne Shell Builtins.
(line 460)
-* unalias: Bash Builtins. (line 785)
+* unalias: Bash Builtins. (line 788)
* unset: Bourne Shell Builtins.
(line 478)
* wait: Job Control Builtins.
* !: Pipelines. (line 9)
* [[: Conditional Constructs.
- (line 126)
+ (line 125)
* ]]: Conditional Constructs.
- (line 126)
+ (line 125)
* {: Command Grouping. (line 21)
* }: Command Grouping. (line 21)
* case: Conditional Constructs.
* in: Conditional Constructs.
(line 28)
* select: Conditional Constructs.
- (line 84)
+ (line 83)
* then: Conditional Constructs.
(line 7)
* time: Pipelines. (line 9)
\0\b[index\0\b]
* Menu:
+* _: Bash Variables. (line 13)
+* -: Special Parameters. (line 46)
* !: Special Parameters. (line 55)
+* ?: Special Parameters. (line 42)
+* @: Special Parameters. (line 22)
+* *: Special Parameters. (line 9)
* #: Special Parameters. (line 39)
* $: Special Parameters. (line 51)
+* $_: Bash Variables. (line 14)
+* $-: Special Parameters. (line 47)
* $!: Special Parameters. (line 56)
+* $?: Special Parameters. (line 43)
+* $@: Special Parameters. (line 23)
+* $*: Special Parameters. (line 10)
* $#: Special Parameters. (line 40)
* $$: Special Parameters. (line 52)
-* $*: Special Parameters. (line 10)
-* $-: Special Parameters. (line 47)
* $0: Special Parameters. (line 61)
-* $?: Special Parameters. (line 43)
-* $@: Special Parameters. (line 23)
-* $_: Bash Variables. (line 14)
-* *: Special Parameters. (line 9)
-* -: Special Parameters. (line 46)
* 0: Special Parameters. (line 60)
-* ?: Special Parameters. (line 42)
-* @: Special Parameters. (line 22)
-* _: Bash Variables. (line 13)
* active-region-end-color: Readline Init File Syntax.
(line 51)
* active-region-start-color: Readline Init File Syntax.
* auto_resume: Job Control Variables.
(line 6)
* BASH: Bash Variables. (line 23)
-* BASHOPTS: Bash Variables. (line 26)
-* BASHPID: Bash Variables. (line 35)
* BASH_ALIASES: Bash Variables. (line 42)
* BASH_ARGC: Bash Variables. (line 51)
* BASH_ARGV: Bash Variables. (line 65)
* BASH_VERSINFO: Bash Variables. (line 176)
* BASH_VERSION: Bash Variables. (line 199)
* BASH_XTRACEFD: Bash Variables. (line 202)
+* BASHOPTS: Bash Variables. (line 26)
+* BASHPID: Bash Variables. (line 35)
* bell-style: Readline Init File Syntax.
(line 64)
* bind-tty-special-chars: Readline Init File Syntax.
* COLUMNS: Bash Variables. (line 220)
* comment-begin: Readline Init File Syntax.
(line 100)
+* COMP_CWORD: Bash Variables. (line 226)
+* COMP_KEY: Bash Variables. (line 255)
+* COMP_LINE: Bash Variables. (line 232)
+* COMP_POINT: Bash Variables. (line 237)
+* COMP_TYPE: Bash Variables. (line 245)
+* COMP_WORDBREAKS: Bash Variables. (line 259)
+* COMP_WORDS: Bash Variables. (line 265)
* completion-display-width: Readline Init File Syntax.
(line 105)
* completion-ignore-case: Readline Init File Syntax.
* completion-query-items: Readline Init File Syntax.
(line 130)
* COMPREPLY: Bash Variables. (line 272)
-* COMP_CWORD: Bash Variables. (line 226)
-* COMP_KEY: Bash Variables. (line 255)
-* COMP_LINE: Bash Variables. (line 232)
-* COMP_POINT: Bash Variables. (line 237)
-* COMP_TYPE: Bash Variables. (line 245)
-* COMP_WORDBREAKS: Bash Variables. (line 259)
-* COMP_WORDS: Bash Variables. (line 265)
* convert-meta: Readline Init File Syntax.
(line 141)
* COPROC: Bash Variables. (line 278)
(line 13)
* horizontal-scroll-mode: Readline Init File Syntax.
(line 229)
-* HOSTFILE: Bash Variables. (line 493)
-* HOSTNAME: Bash Variables. (line 504)
-* HOSTTYPE: Bash Variables. (line 507)
+* HOSTFILE: Bash Variables. (line 494)
+* HOSTNAME: Bash Variables. (line 505)
+* HOSTTYPE: Bash Variables. (line 508)
* IFS: Bourne Shell Variables.
(line 18)
-* IGNOREEOF: Bash Variables. (line 510)
+* IGNOREEOF: Bash Variables. (line 511)
* input-meta: Readline Init File Syntax.
(line 238)
-* INPUTRC: Bash Variables. (line 520)
-* INSIDE_EMACS: Bash Variables. (line 524)
+* INPUTRC: Bash Variables. (line 521)
+* INSIDE_EMACS: Bash Variables. (line 525)
* isearch-terminators: Readline Init File Syntax.
(line 248)
* keymap: Readline Init File Syntax.
(line 255)
* LANG: Creating Internationalized Scripts.
(line 51)
-* LANG <1>: Bash Variables. (line 530)
-* LC_ALL: Bash Variables. (line 534)
-* LC_COLLATE: Bash Variables. (line 538)
-* LC_CTYPE: Bash Variables. (line 545)
+* LANG <1>: Bash Variables. (line 531)
+* LC_ALL: Bash Variables. (line 535)
+* LC_COLLATE: Bash Variables. (line 539)
+* LC_CTYPE: Bash Variables. (line 546)
* LC_MESSAGES: Creating Internationalized Scripts.
(line 51)
-* LC_MESSAGES <1>: Bash Variables. (line 550)
-* LC_NUMERIC: Bash Variables. (line 554)
-* LC_TIME: Bash Variables. (line 558)
-* LINENO: Bash Variables. (line 562)
-* LINES: Bash Variables. (line 567)
-* MACHTYPE: Bash Variables. (line 573)
+* LC_MESSAGES <1>: Bash Variables. (line 551)
+* LC_NUMERIC: Bash Variables. (line 555)
+* LC_TIME: Bash Variables. (line 559)
+* LINENO: Bash Variables. (line 563)
+* LINES: Bash Variables. (line 568)
+* MACHTYPE: Bash Variables. (line 574)
* MAIL: Bourne Shell Variables.
(line 22)
-* MAILCHECK: Bash Variables. (line 577)
+* MAILCHECK: Bash Variables. (line 578)
* MAILPATH: Bourne Shell Variables.
(line 27)
-* MAPFILE: Bash Variables. (line 585)
+* MAPFILE: Bash Variables. (line 586)
* mark-modified-lines: Readline Init File Syntax.
(line 285)
* mark-symlinked-directories: Readline Init File Syntax.
(line 302)
* meta-flag: Readline Init File Syntax.
(line 238)
-* OLDPWD: Bash Variables. (line 589)
+* OLDPWD: Bash Variables. (line 590)
* OPTARG: Bourne Shell Variables.
(line 34)
-* OPTERR: Bash Variables. (line 592)
+* OPTERR: Bash Variables. (line 593)
* OPTIND: Bourne Shell Variables.
(line 38)
-* OSTYPE: Bash Variables. (line 596)
+* OSTYPE: Bash Variables. (line 597)
* output-meta: Readline Init File Syntax.
(line 307)
* page-completions: Readline Init File Syntax.
(line 315)
* PATH: Bourne Shell Variables.
(line 42)
-* PIPESTATUS: Bash Variables. (line 599)
-* POSIXLY_CORRECT: Bash Variables. (line 604)
-* PPID: Bash Variables. (line 614)
-* PROMPT_COMMAND: Bash Variables. (line 618)
-* PROMPT_DIRTRIM: Bash Variables. (line 624)
-* PS0: Bash Variables. (line 630)
+* PIPESTATUS: Bash Variables. (line 600)
+* POSIXLY_CORRECT: Bash Variables. (line 605)
+* PPID: Bash Variables. (line 615)
+* PROMPT_COMMAND: Bash Variables. (line 619)
+* PROMPT_DIRTRIM: Bash Variables. (line 625)
+* PS0: Bash Variables. (line 631)
* PS1: Bourne Shell Variables.
(line 48)
* PS2: Bourne Shell Variables.
(line 53)
-* PS3: Bash Variables. (line 635)
-* PS4: Bash Variables. (line 640)
-* PWD: Bash Variables. (line 648)
-* RANDOM: Bash Variables. (line 651)
-* READLINE_ARGUMENT: Bash Variables. (line 657)
-* READLINE_LINE: Bash Variables. (line 661)
-* READLINE_MARK: Bash Variables. (line 665)
-* READLINE_POINT: Bash Variables. (line 671)
-* REPLY: Bash Variables. (line 675)
+* PS3: Bash Variables. (line 636)
+* PS4: Bash Variables. (line 641)
+* PWD: Bash Variables. (line 649)
+* RANDOM: Bash Variables. (line 652)
+* READLINE_ARGUMENT: Bash Variables. (line 658)
+* READLINE_LINE: Bash Variables. (line 662)
+* READLINE_MARK: Bash Variables. (line 666)
+* READLINE_POINT: Bash Variables. (line 672)
+* REPLY: Bash Variables. (line 676)
* revert-all-at-newline: Readline Init File Syntax.
(line 325)
* search-ignore-case: Readline Init File Syntax.
(line 332)
-* SECONDS: Bash Variables. (line 678)
-* SHELL: Bash Variables. (line 687)
-* SHELLOPTS: Bash Variables. (line 692)
-* SHLVL: Bash Variables. (line 701)
+* SECONDS: Bash Variables. (line 679)
+* SHELL: Bash Variables. (line 688)
+* SHELLOPTS: Bash Variables. (line 693)
+* SHLVL: Bash Variables. (line 702)
* show-all-if-ambiguous: Readline Init File Syntax.
(line 337)
* show-all-if-unmodified: Readline Init File Syntax.
(line 352)
* skip-completed-text: Readline Init File Syntax.
(line 358)
-* SRANDOM: Bash Variables. (line 706)
+* SRANDOM: Bash Variables. (line 707)
* TEXTDOMAIN: Creating Internationalized Scripts.
(line 51)
* TEXTDOMAINDIR: Creating Internationalized Scripts.
(line 51)
-* TIMEFORMAT: Bash Variables. (line 715)
-* TMOUT: Bash Variables. (line 753)
-* TMPDIR: Bash Variables. (line 765)
-* UID: Bash Variables. (line 769)
+* TIMEFORMAT: Bash Variables. (line 716)
+* TMOUT: Bash Variables. (line 754)
+* TMPDIR: Bash Variables. (line 766)
+* UID: Bash Variables. (line 770)
* vi-cmd-mode-string: Readline Init File Syntax.
(line 371)
* vi-ins-mode-string: Readline Init File Syntax.
* accept-line (Newline or Return): Commands For History.
(line 6)
* alias-expand-line (): Miscellaneous Commands.
- (line 132)
+ (line 133)
* backward-char (C-b): Commands For Moving. (line 15)
* backward-delete-char (Rubout): Commands For Text. (line 17)
* backward-kill-line (C-x Rubout): Commands For Killing.
* dynamic-complete-history (M-<TAB>): Commands For Completion.
(line 90)
* edit-and-execute-command (C-x C-e): Miscellaneous Commands.
- (line 141)
+ (line 142)
* end-kbd-macro (C-x )): Keyboard Macros. (line 9)
* end-of-file (usually C-d): Commands For Text. (line 6)
* end-of-history (M->): Commands For History.
* exchange-point-and-mark (C-x C-x): Miscellaneous Commands.
(line 37)
* execute-named-command (M-x): Miscellaneous Commands.
- (line 146)
+ (line 147)
* fetch-history (): Commands For History.
(line 103)
* forward-backward-delete-char (): Commands For Text. (line 21)
* glob-list-expansions (C-x g): Miscellaneous Commands.
(line 110)
* history-and-alias-expand-line (): Miscellaneous Commands.
- (line 135)
+ (line 136)
* history-expand-line (M-^): Miscellaneous Commands.
- (line 125)
+ (line 126)
* history-search-backward (): Commands For History.
(line 57)
* history-search-forward (): Commands For History.
* insert-completions (M-*): Commands For Completion.
(line 22)
* insert-last-argument (M-. or M-_): Miscellaneous Commands.
- (line 138)
+ (line 139)
* kill-line (C-k): Commands For Killing.
(line 6)
* kill-region (): Commands For Killing.
* kill-word (M-d): Commands For Killing.
(line 23)
* magic-space (): Miscellaneous Commands.
- (line 128)
+ (line 129)
* menu-complete (): Commands For Completion.
(line 26)
* menu-complete-backward (): Commands For Completion.
\1f
Tag Table:
-Node: Top\7f894
-Node: Introduction\7f2811
-Node: What is Bash?\7f3024
-Node: What is a shell?\7f4135
-Node: Definitions\7f6670
-Node: Basic Shell Features\7f9618
-Node: Shell Syntax\7f10834
-Node: Shell Operation\7f11857
-Node: Quoting\7f13147
-Node: Escape Character\7f14448
-Node: Single Quotes\7f14930
-Node: Double Quotes\7f15275
-Node: ANSI-C Quoting\7f16550
-Node: Locale Translation\7f17859
-Node: Creating Internationalized Scripts\7f19167
-Node: Comments\7f23281
-Node: Shell Commands\7f23896
-Node: Reserved Words\7f24831
-Node: Simple Commands\7f25584
-Node: Pipelines\7f26235
-Node: Lists\7f29218
-Node: Compound Commands\7f31010
-Node: Looping Constructs\7f32019
-Node: Conditional Constructs\7f34511
-Node: Command Grouping\7f48996
-Node: Coprocesses\7f50471
-Node: GNU Parallel\7f53131
-Node: Shell Functions\7f54045
-Node: Shell Parameters\7f61927
-Node: Positional Parameters\7f66312
-Node: Special Parameters\7f67211
-Node: Shell Expansions\7f70422
-Node: Brace Expansion\7f72507
-Node: Tilde Expansion\7f75238
-Node: Shell Parameter Expansion\7f77856
-Node: Command Substitution\7f96446
-Node: Arithmetic Expansion\7f99907
-Node: Process Substitution\7f100872
-Node: Word Splitting\7f101989
-Node: Filename Expansion\7f104034
-Node: Pattern Matching\7f106964
-Node: Quote Removal\7f111963
-Node: Redirections\7f112255
-Node: Executing Commands\7f121946
-Node: Simple Command Expansion\7f122613
-Node: Command Search and Execution\7f124720
-Node: Command Execution Environment\7f127104
-Node: Environment\7f130136
-Node: Exit Status\7f131796
-Node: Signals\7f133577
-Node: Shell Scripts\7f137023
-Node: Shell Builtin Commands\7f140047
-Node: Bourne Shell Builtins\7f142082
-Node: Bash Builtins\7f165471
-Node: Modifying Shell Behavior\7f198688
-Node: The Set Builtin\7f199030
-Node: The Shopt Builtin\7f210001
-Node: Special Builtins\7f226193
-Node: Shell Variables\7f227182
-Node: Bourne Shell Variables\7f227616
-Node: Bash Variables\7f229717
-Node: Bash Features\7f264783
-Node: Invoking Bash\7f265793
-Node: Bash Startup Files\7f271924
-Node: Interactive Shells\7f277052
-Node: What is an Interactive Shell?\7f277460
-Node: Is this Shell Interactive?\7f278106
-Node: Interactive Shell Behavior\7f278918
-Node: Bash Conditional Expressions\7f282544
-Node: Shell Arithmetic\7f287454
-Node: Aliases\7f290412
-Node: Arrays\7f293303
-Node: The Directory Stack\7f299934
-Node: Directory Stack Builtins\7f300715
-Node: Controlling the Prompt\7f304972
-Node: The Restricted Shell\7f307934
-Node: Bash POSIX Mode\7f310541
-Node: Shell Compatibility Mode\7f327455
-Node: Job Control\7f335703
-Node: Job Control Basics\7f336160
-Node: Job Control Builtins\7f341159
-Node: Job Control Variables\7f346951
-Node: Command Line Editing\7f348104
-Node: Introduction and Notation\7f349772
-Node: Readline Interaction\7f351392
-Node: Readline Bare Essentials\7f352580
-Node: Readline Movement Commands\7f354366
-Node: Readline Killing Commands\7f355323
-Node: Readline Arguments\7f357241
-Node: Searching\7f358282
-Node: Readline Init File\7f360465
-Node: Readline Init File Syntax\7f361723
-Node: Conditional Init Constructs\7f385745
-Node: Sample Init File\7f389938
-Node: Bindable Readline Commands\7f393059
-Node: Commands For Moving\7f394260
-Node: Commands For History\7f396308
-Node: Commands For Text\7f401299
-Node: Commands For Killing\7f405274
-Node: Numeric Arguments\7f407975
-Node: Commands For Completion\7f409111
-Node: Keyboard Macros\7f413299
-Node: Miscellaneous Commands\7f413984
-Node: Readline vi Mode\7f420350
-Node: Programmable Completion\7f421254
-Node: Programmable Completion Builtins\7f429031
-Node: A Programmable Completion Example\7f440148
-Node: Using History Interactively\7f445393
-Node: Bash History Facilities\7f446074
-Node: Bash History Builtins\7f449082
-Node: History Interaction\7f454170
-Node: Event Designators\7f458419
-Node: Word Designators\7f459954
-Node: Modifiers\7f461816
-Node: Installing Bash\7f463621
-Node: Basic Installation\7f464755
-Node: Compilers and Options\7f468474
-Node: Compiling For Multiple Architectures\7f469212
-Node: Installation Names\7f470901
-Node: Specifying the System Type\7f473007
-Node: Sharing Defaults\7f473721
-Node: Operation Controls\7f474391
-Node: Optional Features\7f475346
-Node: Reporting Bugs\7f486563
-Node: Major Differences From The Bourne Shell\7f487894
-Node: GNU Free Documentation License\7f504749
-Node: Indexes\7f529923
-Node: Builtin Index\7f530374
-Node: Reserved Word Index\7f537472
-Node: Variable Index\7f539917
-Node: Function Index\7f557048
-Node: Concept Index\7f570904
+Node: Top\7f899
+Node: Introduction\7f2838
+Node: What is Bash?\7f3051
+Node: What is a shell?\7f4192
+Node: Definitions\7f6771
+Node: Basic Shell Features\7f9947
+Node: Shell Syntax\7f11167
+Node: Shell Operation\7f12194
+Node: Quoting\7f13492
+Node: Escape Character\7f14805
+Node: Single Quotes\7f15303
+Node: Double Quotes\7f15652
+Node: ANSI-C Quoting\7f16995
+Node: Locale Translation\7f18380
+Node: Creating Internationalized Scripts\7f19724
+Node: Comments\7f23922
+Node: Shell Commands\7f24557
+Node: Reserved Words\7f25496
+Node: Simple Commands\7f26361
+Node: Pipelines\7f27020
+Node: Lists\7f30083
+Node: Compound Commands\7f31955
+Node: Looping Constructs\7f32964
+Node: Conditional Constructs\7f35508
+Node: Command Grouping\7f50412
+Node: Coprocesses\7f51899
+Node: GNU Parallel\7f54595
+Node: Shell Functions\7f55513
+Node: Shell Parameters\7f63619
+Node: Positional Parameters\7f68152
+Node: Special Parameters\7f69087
+Node: Shell Expansions\7f72394
+Node: Brace Expansion\7f74583
+Node: Tilde Expansion\7f77246
+Node: Shell Parameter Expansion\7f80012
+Node: Command Substitution\7f99036
+Node: Arithmetic Expansion\7f102569
+Node: Process Substitution\7f103534
+Node: Word Splitting\7f104671
+Node: Filename Expansion\7f106812
+Node: Pattern Matching\7f109908
+Node: Quote Removal\7f115141
+Node: Redirections\7f115445
+Node: Executing Commands\7f125254
+Node: Simple Command Expansion\7f125921
+Node: Command Search and Execution\7f128032
+Node: Command Execution Environment\7f130440
+Node: Environment\7f133749
+Node: Exit Status\7f135453
+Node: Signals\7f137238
+Node: Shell Scripts\7f140852
+Node: Shell Builtin Commands\7f143944
+Node: Bourne Shell Builtins\7f146055
+Node: Bash Builtins\7f170459
+Node: Modifying Shell Behavior\7f205064
+Node: The Set Builtin\7f205406
+Node: The Shopt Builtin\7f216921
+Node: Special Builtins\7f233657
+Node: Shell Variables\7f234646
+Node: Bourne Shell Variables\7f235080
+Node: Bash Variables\7f237273
+Node: Bash Features\7f273695
+Node: Invoking Bash\7f274709
+Node: Bash Startup Files\7f281108
+Node: Interactive Shells\7f286420
+Node: What is an Interactive Shell?\7f286828
+Node: Is this Shell Interactive?\7f287494
+Node: Interactive Shell Behavior\7f288318
+Node: Bash Conditional Expressions\7f292072
+Node: Shell Arithmetic\7f297246
+Node: Aliases\7f300328
+Node: Arrays\7f303283
+Node: The Directory Stack\7f310082
+Node: Directory Stack Builtins\7f310879
+Node: Controlling the Prompt\7f315328
+Node: The Restricted Shell\7f318466
+Node: Bash POSIX Mode\7f321253
+Node: Shell Compatibility Mode\7f338734
+Node: Job Control\7f347220
+Node: Job Control Basics\7f347677
+Node: Job Control Builtins\7f352851
+Node: Job Control Variables\7f358811
+Node: Command Line Editing\7f359988
+Node: Introduction and Notation\7f361692
+Node: Readline Interaction\7f363336
+Node: Readline Bare Essentials\7f364524
+Node: Readline Movement Commands\7f366342
+Node: Readline Killing Commands\7f367339
+Node: Readline Arguments\7f369317
+Node: Searching\7f370374
+Node: Readline Init File\7f372603
+Node: Readline Init File Syntax\7f373885
+Node: Conditional Init Constructs\7f398823
+Node: Sample Init File\7f403188
+Node: Bindable Readline Commands\7f406309
+Node: Commands For Moving\7f407534
+Node: Commands For History\7f409634
+Node: Commands For Text\7f414717
+Node: Commands For Killing\7f418792
+Node: Numeric Arguments\7f421593
+Node: Commands For Completion\7f422745
+Node: Keyboard Macros\7f427061
+Node: Miscellaneous Commands\7f427762
+Node: Readline vi Mode\7f434416
+Node: Programmable Completion\7f435368
+Node: Programmable Completion Builtins\7f443325
+Node: A Programmable Completion Example\7f454891
+Node: Using History Interactively\7f460236
+Node: Bash History Facilities\7f460917
+Node: Bash History Builtins\7f464029
+Node: History Interaction\7f469272
+Node: Event Designators\7f473597
+Node: Word Designators\7f475180
+Node: Modifiers\7f477166
+Node: Installing Bash\7f479075
+Node: Basic Installation\7f480209
+Node: Compilers and Options\7f484088
+Node: Compiling For Multiple Architectures\7f484838
+Node: Installation Names\7f486587
+Node: Specifying the System Type\7f488821
+Node: Sharing Defaults\7f489567
+Node: Operation Controls\7f490281
+Node: Optional Features\7f491300
+Node: Reporting Bugs\7f503102
+Node: Major Differences From The Bourne Shell\7f504451
+Node: GNU Free Documentation License\7f522260
+Node: Indexes\7f547437
+Node: Builtin Index\7f547888
+Node: Reserved Word Index\7f554986
+Node: Variable Index\7f557431
+Node: Function Index\7f574562
+Node: Concept Index\7f588418
\1f
End Tag Table
-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<!DOCTYPE html>
<html>
-<!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ -->
+<!-- Created by GNU Texinfo 7.1, https://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<!-- This text is a brief description of the features that are present in
-the Bash shell (version 5.3, 14 December 2023).
+the Bash shell (version 5.3, 2 February 2024).
-This is Edition 5.3, last updated 14 December 2023,
+This is Edition 5.3, last updated 2 February 2024,
of The GNU Bash Reference Manual,
for Bash, Version 5.3.
-Copyright (C) 1988-2023 Free Software Foundation, Inc.
+Copyright © 1988-2023 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
<link href="dir.html#Top" rel="prev" title="(dir)">
<style type="text/css">
<!--
-a.copiable-anchor {visibility: hidden; text-decoration: none; line-height: 0em}
-a.summary-letter {text-decoration: none}
-blockquote.indentedblock {margin-right: 0em}
+a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
+a.summary-letter-printindex {text-decoration: none}
+div.center {text-align:center}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
-kbd {font-style: oblique}
-pre.display {font-family: inherit}
-pre.format {font-family: inherit}
-pre.menu-comment {font-family: serif}
-pre.menu-preformatted {font-family: serif}
-span.nolinebreak {white-space: nowrap}
-span.roman {font-family: initial; font-weight: normal}
-span.sansserif {font-family: sans-serif; font-weight: normal}
-span:hover a.copiable-anchor {visibility: visible}
-ul.no-bullet {list-style: none}
+kbd.kbd {font-style: oblique}
+kbd.key {font-style: normal}
+pre.display-preformatted {font-family: inherit}
+span.r {font-family: initial; font-weight: normal; font-style: normal}
+span:hover a.copiable-link {visibility: visible}
+td.printindex-index-entry {vertical-align: top}
+td.printindex-index-section {vertical-align: top; padding-left: 1em}
+th.entries-header-printindex {text-align:left}
+th.sections-header-printindex {text-align:left; padding-left: 1em}
+ul.mark-bullet {list-style-type: disc}
+ul.toc-numbered-mark {list-style: none}
-->
</style>
</head>
<body lang="en">
-<h1 class="settitle" align="center">Bash Reference Manual</h1>
-<div class="top" id="Top">
-<div class="header">
+<div class="top-level-extent" id="Top">
+<div class="nav-panel">
<p>
Next: <a href="#Introduction" accesskey="n" rel="next">Introduction</a>, Previous: <a href="dir.html#Top" accesskey="p" rel="prev">(dir)</a>, Up: <a href="dir.html#Top" accesskey="u" rel="up">(dir)</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-Features-1"></span><h1 class="top">Bash Features</h1>
+<h1 class="top" id="Bash-Features-1"><span>Bash Features<a class="copiable-link" href="#Bash-Features-1"> ¶</a></span></h1>
<p>This text is a brief description of the features that are present in
-the Bash shell (version 5.3, 14 December 2023).
-The Bash home page is <a href="http://www.gnu.org/software/bash/">http://www.gnu.org/software/bash/</a>.
+the Bash shell (version 5.3, 2 February 2024).
+The Bash home page is <a class="url" href="http://www.gnu.org/software/bash/">http://www.gnu.org/software/bash/</a>.
</p>
-<p>This is Edition 5.3, last updated 14 December 2023,
-of <cite>The GNU Bash Reference Manual</cite>,
-for <code>Bash</code>, Version 5.3.
+<p>This is Edition 5.3, last updated 2 February 2024,
+of <cite class="cite">The GNU Bash Reference Manual</cite>,
+for <code class="code">Bash</code>, Version 5.3.
</p>
<p>Bash contains features that appear in other popular shells, and some
features that only appear in Bash. Some of the shells that Bash has
-borrowed concepts from are the Bourne Shell (<samp>sh</samp>), the Korn Shell
-(<samp>ksh</samp>), and the C-shell (<samp>csh</samp> and its successor,
-<samp>tcsh</samp>). The following menu breaks the features up into
+borrowed concepts from are the Bourne Shell (<samp class="file">sh</samp>), the Korn Shell
+(<samp class="file">ksh</samp>), and the C-shell (<samp class="file">csh</samp> and its successor,
+<samp class="file">tcsh</samp>). The following menu breaks the features up into
categories, noting which features were inspired by other shells and
which are specific to Bash.
</p>
reference on shell behavior.
</p>
-<div class="Contents_element" id="SEC_Contents">
+<div class="element-contents" id="SEC_Contents">
<h2 class="contents-heading">Table of Contents</h2>
<div class="contents">
-<ul class="no-bullet">
+<ul class="toc-numbered-mark">
<li><a id="toc-Introduction-1" href="#Introduction">1 Introduction</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-What-is-Bash_003f-1" href="#What-is-Bash_003f">1.1 What is Bash?</a></li>
<li><a id="toc-What-is-a-shell_003f-1" href="#What-is-a-shell_003f">1.2 What is a shell?</a></li>
</ul></li>
<li><a id="toc-Definitions-1" href="#Definitions">2 Definitions</a></li>
<li><a id="toc-Basic-Shell-Features-1" href="#Basic-Shell-Features">3 Basic Shell Features</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Shell-Syntax-1" href="#Shell-Syntax">3.1 Shell Syntax</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Shell-Operation-1" href="#Shell-Operation">3.1.1 Shell Operation</a></li>
<li><a id="toc-Quoting-1" href="#Quoting">3.1.2 Quoting</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Escape-Character-1" href="#Escape-Character">3.1.2.1 Escape Character</a></li>
<li><a id="toc-Single-Quotes-1" href="#Single-Quotes">3.1.2.2 Single Quotes</a></li>
<li><a id="toc-Double-Quotes-1" href="#Double-Quotes">3.1.2.3 Double Quotes</a></li>
<li><a id="toc-Comments-1" href="#Comments">3.1.3 Comments</a></li>
</ul></li>
<li><a id="toc-Shell-Commands-1" href="#Shell-Commands">3.2 Shell Commands</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Reserved-Words-1" href="#Reserved-Words">3.2.1 Reserved Words</a></li>
<li><a id="toc-Simple-Commands-1" href="#Simple-Commands">3.2.2 Simple Commands</a></li>
<li><a id="toc-Pipelines-1" href="#Pipelines">3.2.3 Pipelines</a></li>
<li><a id="toc-Lists-of-Commands" href="#Lists">3.2.4 Lists of Commands</a></li>
<li><a id="toc-Compound-Commands-1" href="#Compound-Commands">3.2.5 Compound Commands</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Looping-Constructs-1" href="#Looping-Constructs">3.2.5.1 Looping Constructs</a></li>
<li><a id="toc-Conditional-Constructs-1" href="#Conditional-Constructs">3.2.5.2 Conditional Constructs</a></li>
<li><a id="toc-Grouping-Commands" href="#Command-Grouping">3.2.5.3 Grouping Commands</a></li>
</ul></li>
<li><a id="toc-Shell-Functions-1" href="#Shell-Functions">3.3 Shell Functions</a></li>
<li><a id="toc-Shell-Parameters-1" href="#Shell-Parameters">3.4 Shell Parameters</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Positional-Parameters-1" href="#Positional-Parameters">3.4.1 Positional Parameters</a></li>
<li><a id="toc-Special-Parameters-1" href="#Special-Parameters">3.4.2 Special Parameters</a></li>
</ul></li>
<li><a id="toc-Shell-Expansions-1" href="#Shell-Expansions">3.5 Shell Expansions</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Brace-Expansion-1" href="#Brace-Expansion">3.5.1 Brace Expansion</a></li>
<li><a id="toc-Tilde-Expansion-1" href="#Tilde-Expansion">3.5.2 Tilde Expansion</a></li>
<li><a id="toc-Shell-Parameter-Expansion-1" href="#Shell-Parameter-Expansion">3.5.3 Shell Parameter Expansion</a></li>
<li><a id="toc-Process-Substitution-1" href="#Process-Substitution">3.5.6 Process Substitution</a></li>
<li><a id="toc-Word-Splitting-1" href="#Word-Splitting">3.5.7 Word Splitting</a></li>
<li><a id="toc-Filename-Expansion-1" href="#Filename-Expansion">3.5.8 Filename Expansion</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Pattern-Matching-1" href="#Pattern-Matching">3.5.8.1 Pattern Matching</a></li>
</ul></li>
<li><a id="toc-Quote-Removal-1" href="#Quote-Removal">3.5.9 Quote Removal</a></li>
</ul></li>
<li><a id="toc-Redirections-1" href="#Redirections">3.6 Redirections</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Redirecting-Input" href="#Redirecting-Input">3.6.1 Redirecting Input</a></li>
<li><a id="toc-Redirecting-Output" href="#Redirecting-Output">3.6.2 Redirecting Output</a></li>
<li><a id="toc-Appending-Redirected-Output" href="#Appending-Redirected-Output">3.6.3 Appending Redirected Output</a></li>
<li><a id="toc-Opening-File-Descriptors-for-Reading-and-Writing" href="#Opening-File-Descriptors-for-Reading-and-Writing">3.6.10 Opening File Descriptors for Reading and Writing</a></li>
</ul></li>
<li><a id="toc-Executing-Commands-1" href="#Executing-Commands">3.7 Executing Commands</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Simple-Command-Expansion-1" href="#Simple-Command-Expansion">3.7.1 Simple Command Expansion</a></li>
<li><a id="toc-Command-Search-and-Execution-1" href="#Command-Search-and-Execution">3.7.2 Command Search and Execution</a></li>
<li><a id="toc-Command-Execution-Environment-1" href="#Command-Execution-Environment">3.7.3 Command Execution Environment</a></li>
<li><a id="toc-Shell-Scripts-1" href="#Shell-Scripts">3.8 Shell Scripts</a></li>
</ul></li>
<li><a id="toc-Shell-Builtin-Commands-1" href="#Shell-Builtin-Commands">4 Shell Builtin Commands</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Bourne-Shell-Builtins-1" href="#Bourne-Shell-Builtins">4.1 Bourne Shell Builtins</a></li>
<li><a id="toc-Bash-Builtin-Commands" href="#Bash-Builtins">4.2 Bash Builtin Commands</a></li>
<li><a id="toc-Modifying-Shell-Behavior-1" href="#Modifying-Shell-Behavior">4.3 Modifying Shell Behavior</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-The-Set-Builtin-1" href="#The-Set-Builtin">4.3.1 The Set Builtin</a></li>
<li><a id="toc-The-Shopt-Builtin-1" href="#The-Shopt-Builtin">4.3.2 The Shopt Builtin</a></li>
</ul></li>
<li><a id="toc-Special-Builtins-1" href="#Special-Builtins">4.4 Special Builtins</a></li>
</ul></li>
<li><a id="toc-Shell-Variables-1" href="#Shell-Variables">5 Shell Variables</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Bourne-Shell-Variables-1" href="#Bourne-Shell-Variables">5.1 Bourne Shell Variables</a></li>
<li><a id="toc-Bash-Variables-1" href="#Bash-Variables">5.2 Bash Variables</a></li>
</ul></li>
<li><a id="toc-Bash-Features-2" href="#Bash-Features">6 Bash Features</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Invoking-Bash-1" href="#Invoking-Bash">6.1 Invoking Bash</a></li>
<li><a id="toc-Bash-Startup-Files-1" href="#Bash-Startup-Files">6.2 Bash Startup Files</a></li>
<li><a id="toc-Interactive-Shells-1" href="#Interactive-Shells">6.3 Interactive Shells</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-What-is-an-Interactive-Shell_003f-1" href="#What-is-an-Interactive-Shell_003f">6.3.1 What is an Interactive Shell?</a></li>
<li><a id="toc-Is-this-Shell-Interactive_003f-1" href="#Is-this-Shell-Interactive_003f">6.3.2 Is this Shell Interactive?</a></li>
<li><a id="toc-Interactive-Shell-Behavior-1" href="#Interactive-Shell-Behavior">6.3.3 Interactive Shell Behavior</a></li>
<li><a id="toc-Aliases-1" href="#Aliases">6.6 Aliases</a></li>
<li><a id="toc-Arrays-1" href="#Arrays">6.7 Arrays</a></li>
<li><a id="toc-The-Directory-Stack-1" href="#The-Directory-Stack">6.8 The Directory Stack</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Directory-Stack-Builtins-1" href="#Directory-Stack-Builtins">6.8.1 Directory Stack Builtins</a></li>
</ul></li>
<li><a id="toc-Controlling-the-Prompt-1" href="#Controlling-the-Prompt">6.9 Controlling the Prompt</a></li>
<li><a id="toc-The-Restricted-Shell-1" href="#The-Restricted-Shell">6.10 The Restricted Shell</a></li>
<li><a id="toc-Bash-and-POSIX" href="#Bash-POSIX-Mode">6.11 Bash and POSIX</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-What-is-POSIX_003f" href="#What-is-POSIX_003f">6.11.1 What is POSIX?</a></li>
<li><a id="toc-Bash-POSIX-Mode-1" href="#Bash-POSIX-Mode-1">6.11.2 Bash POSIX Mode</a></li>
</ul></li>
<li><a id="toc-Shell-Compatibility-Mode-1" href="#Shell-Compatibility-Mode">6.12 Shell Compatibility Mode</a></li>
</ul></li>
<li><a id="toc-Job-Control-1" href="#Job-Control">7 Job Control</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Job-Control-Basics-1" href="#Job-Control-Basics">7.1 Job Control Basics</a></li>
<li><a id="toc-Job-Control-Builtins-1" href="#Job-Control-Builtins">7.2 Job Control Builtins</a></li>
<li><a id="toc-Job-Control-Variables-1" href="#Job-Control-Variables">7.3 Job Control Variables</a></li>
</ul></li>
<li><a id="toc-Command-Line-Editing-1" href="#Command-Line-Editing">8 Command Line Editing</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Introduction-to-Line-Editing" href="#Introduction-and-Notation">8.1 Introduction to Line Editing</a></li>
<li><a id="toc-Readline-Interaction-1" href="#Readline-Interaction">8.2 Readline Interaction</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Readline-Bare-Essentials-1" href="#Readline-Bare-Essentials">8.2.1 Readline Bare Essentials</a></li>
<li><a id="toc-Readline-Movement-Commands-1" href="#Readline-Movement-Commands">8.2.2 Readline Movement Commands</a></li>
<li><a id="toc-Readline-Killing-Commands-1" href="#Readline-Killing-Commands">8.2.3 Readline Killing Commands</a></li>
<li><a id="toc-Searching-for-Commands-in-the-History" href="#Searching">8.2.5 Searching for Commands in the History</a></li>
</ul></li>
<li><a id="toc-Readline-Init-File-1" href="#Readline-Init-File">8.3 Readline Init File</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Readline-Init-File-Syntax-1" href="#Readline-Init-File-Syntax">8.3.1 Readline Init File Syntax</a></li>
<li><a id="toc-Conditional-Init-Constructs-1" href="#Conditional-Init-Constructs">8.3.2 Conditional Init Constructs</a></li>
<li><a id="toc-Sample-Init-File-1" href="#Sample-Init-File">8.3.3 Sample Init File</a></li>
</ul></li>
<li><a id="toc-Bindable-Readline-Commands-1" href="#Bindable-Readline-Commands">8.4 Bindable Readline Commands</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Commands-For-Moving-1" href="#Commands-For-Moving">8.4.1 Commands For Moving</a></li>
<li><a id="toc-Commands-For-Manipulating-The-History" href="#Commands-For-History">8.4.2 Commands For Manipulating The History</a></li>
<li><a id="toc-Commands-For-Changing-Text" href="#Commands-For-Text">8.4.3 Commands For Changing Text</a></li>
<li><a id="toc-A-Programmable-Completion-Example-1" href="#A-Programmable-Completion-Example">8.8 A Programmable Completion Example</a></li>
</ul></li>
<li><a id="toc-Using-History-Interactively-1" href="#Using-History-Interactively">9 Using History Interactively</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Bash-History-Facilities-1" href="#Bash-History-Facilities">9.1 Bash History Facilities</a></li>
<li><a id="toc-Bash-History-Builtins-1" href="#Bash-History-Builtins">9.2 Bash History Builtins</a></li>
<li><a id="toc-History-Expansion" href="#History-Interaction">9.3 History Expansion</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Event-Designators-1" href="#Event-Designators">9.3.1 Event Designators</a></li>
<li><a id="toc-Word-Designators-1" href="#Word-Designators">9.3.2 Word Designators</a></li>
<li><a id="toc-Modifiers-1" href="#Modifiers">9.3.3 Modifiers</a></li>
</ul></li>
</ul></li>
<li><a id="toc-Installing-Bash-1" href="#Installing-Bash">10 Installing Bash</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Basic-Installation-1" href="#Basic-Installation">10.1 Basic Installation</a></li>
<li><a id="toc-Compilers-and-Options-1" href="#Compilers-and-Options">10.2 Compilers and Options</a></li>
<li><a id="toc-Compiling-For-Multiple-Architectures-1" href="#Compiling-For-Multiple-Architectures">10.3 Compiling For Multiple Architectures</a></li>
</ul></li>
<li><a id="toc-Reporting-Bugs-1" href="#Reporting-Bugs">Appendix A Reporting Bugs</a></li>
<li><a id="toc-Major-Differences-From-The-Bourne-Shell-1" href="#Major-Differences-From-The-Bourne-Shell">Appendix B Major Differences From The Bourne Shell</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Implementation-Differences-From-The-SVR4_002e2-Shell" href="#Implementation-Differences-From-The-SVR4_002e2-Shell">B.1 Implementation Differences From The SVR4.2 Shell</a></li>
</ul></li>
<li><a id="toc-GNU-Free-Documentation-License-1" href="#GNU-Free-Documentation-License">Appendix C GNU Free Documentation License</a></li>
<li><a id="toc-Indexes-1" href="#Indexes">Appendix D Indexes</a>
- <ul class="no-bullet">
+ <ul class="toc-numbered-mark">
<li><a id="toc-Index-of-Shell-Builtin-Commands" href="#Builtin-Index" rel="index">D.1 Index of Shell Builtin Commands</a></li>
<li><a id="toc-Index-of-Shell-Reserved-Words" href="#Reserved-Word-Index" rel="index">D.2 Index of Shell Reserved Words</a></li>
<li><a id="toc-Parameter-and-Variable-Index" href="#Variable-Index" rel="index">D.3 Parameter and Variable Index</a></li>
</div>
</div>
<hr>
-<div class="chapter" id="Introduction">
-<div class="header">
+<div class="chapter-level-extent" id="Introduction">
+<div class="nav-panel">
<p>
Next: <a href="#Definitions" accesskey="n" rel="next">Definitions</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Introduction-1"></span><h2 class="chapter">1 Introduction</h2>
+<h2 class="chapter" id="Introduction-1"><span>1 Introduction<a class="copiable-link" href="#Introduction-1"> ¶</a></span></h2>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#What-is-Bash_003f" accesskey="1">What is Bash?</a></li>
<li><a href="#What-is-a-shell_003f" accesskey="2">What is a shell?</a></li>
</ul>
<hr>
-<div class="section" id="What-is-Bash_003f">
-<div class="header">
+<div class="section-level-extent" id="What-is-Bash_003f">
+<div class="nav-panel">
<p>
Next: <a href="#What-is-a-shell_003f" accesskey="n" rel="next">What is a shell?</a>, Up: <a href="#Introduction" accesskey="u" rel="up">Introduction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="What-is-Bash_003f-1"></span><h3 class="section">1.1 What is Bash?</h3>
+<h3 class="section" id="What-is-Bash_003f-1"><span>1.1 What is Bash?<a class="copiable-link" href="#What-is-Bash_003f-1"> ¶</a></span></h3>
<p>Bash is the shell, or command language interpreter,
-for the <small>GNU</small> operating system.
-The name is an acronym for the ‘<samp>Bourne-Again SHell</samp>’,
+for the <small class="sc">GNU</small> operating system.
+The name is an acronym for the ‘<samp class="samp">Bourne-Again SHell</samp>’,
a pun on Stephen Bourne, the author of the direct ancestor of
-the current Unix shell <code>sh</code>,
+the current Unix shell <code class="code">sh</code>,
which appeared in the Seventh Edition Bell Labs Research version
of Unix.
</p>
-<p>Bash is largely compatible with <code>sh</code> and incorporates useful
-features from the Korn shell <code>ksh</code> and the C shell <code>csh</code>.
-It is intended to be a conformant implementation of the <small>IEEE</small>
-<small>POSIX</small> Shell and Tools portion of the <small>IEEE</small> <small>POSIX</small>
-specification (<small>IEEE</small> Standard 1003.1).
-It offers functional improvements over <code>sh</code> for both interactive and
+<p>Bash is largely compatible with <code class="code">sh</code> and incorporates useful
+features from the Korn shell <code class="code">ksh</code> and the C shell <code class="code">csh</code>.
+It is intended to be a conformant implementation of the <small class="sc">IEEE</small>
+<small class="sc">POSIX</small> Shell and Tools portion of the <small class="sc">IEEE</small> <small class="sc">POSIX</small>
+specification (<small class="sc">IEEE</small> Standard 1003.1).
+It offers functional improvements over <code class="code">sh</code> for both interactive and
programming use.
</p>
-<p>While the <small>GNU</small> operating system provides other shells, including
-a version of <code>csh</code>, Bash is the default shell.
-Like other <small>GNU</small> software, Bash is quite portable. It currently runs
-on nearly every version of Unix and a few other operating systems -
-independently-supported ports exist for <small>MS-DOS</small>, <small>OS/2</small>,
+<p>While the <small class="sc">GNU</small> operating system provides other shells, including
+a version of <code class="code">csh</code>, Bash is the default shell.
+Like other <small class="sc">GNU</small> software, Bash is quite portable. It currently runs
+on nearly every version of Unix and a few other operating systems −
+independently-supported ports exist for <small class="sc">MS-DOS</small>, <small class="sc">OS/2</small>,
and Windows platforms.
</p>
<hr>
</div>
-<div class="section" id="What-is-a-shell_003f">
-<div class="header">
+<div class="section-level-extent" id="What-is-a-shell_003f">
+<div class="nav-panel">
<p>
Previous: <a href="#What-is-Bash_003f" accesskey="p" rel="prev">What is Bash?</a>, Up: <a href="#Introduction" accesskey="u" rel="up">Introduction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="What-is-a-shell_003f-1"></span><h3 class="section">1.2 What is a shell?</h3>
+<h3 class="section" id="What-is-a-shell_003f-1"><span>1.2 What is a shell?<a class="copiable-link" href="#What-is-a-shell_003f-1"> ¶</a></span></h3>
<p>At its base, a shell is simply a macro processor that executes
commands. The term macro processor means functionality where text
</p>
<p>A Unix shell is both a command interpreter and a programming
language. As a command interpreter, the shell provides the user
-interface to the rich set of <small>GNU</small> utilities. The programming
+interface to the rich set of <small class="sc">GNU</small> utilities. The programming
language features allow these utilities to be combined.
Files containing commands can be created, and become
commands themselves. These new commands have the same status as
-system commands in directories such as <samp>/bin</samp>, allowing users
+system commands in directories such as <samp class="file">/bin</samp>, allowing users
or groups to establish custom environments to automate their common
tasks.
</p>
When executing non-interactively, shells execute commands read
from a file.
</p>
-<p>A shell allows execution of <small>GNU</small> commands, both synchronously and
+<p>A shell allows execution of <small class="sc">GNU</small> commands, both synchronously and
asynchronously.
The shell waits for synchronous commands to complete before accepting
more input; asynchronous commands continue to execute in parallel
with the shell while it reads and executes additional commands.
-The <em>redirection</em> constructs permit
+The <em class="dfn">redirection</em> constructs permit
fine-grained control of the input and output of those commands.
Moreover, the shell allows control over the contents of commands’
environments.
</p>
<p>Shells also provide a small set of built-in
-commands (<em>builtins</em>) implementing functionality impossible
+commands (<em class="dfn">builtins</em>) implementing functionality impossible
or inconvenient to obtain via separate utilities.
-For example, <code>cd</code>, <code>break</code>, <code>continue</code>, and
-<code>exec</code> cannot be implemented outside of the shell because
+For example, <code class="code">cd</code>, <code class="code">break</code>, <code class="code">continue</code>, and
+<code class="code">exec</code> cannot be implemented outside of the shell because
they directly manipulate the shell itself.
-The <code>history</code>, <code>getopts</code>, <code>kill</code>, or <code>pwd</code>
+The <code class="code">history</code>, <code class="code">getopts</code>, <code class="code">kill</code>, or <code class="code">pwd</code>
builtins, among others, could be implemented in separate utilities,
but they are more convenient to use as builtin commands.
All of the shell builtins are described in
<hr>
</div>
</div>
-<div class="chapter" id="Definitions">
-<div class="header">
+<div class="chapter-level-extent" id="Definitions">
+<div class="nav-panel">
<p>
Next: <a href="#Basic-Shell-Features" accesskey="n" rel="next">Basic Shell Features</a>, Previous: <a href="#Introduction" accesskey="p" rel="prev">Introduction</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Definitions-1"></span><h2 class="chapter">2 Definitions</h2>
+<h2 class="chapter" id="Definitions-1"><span>2 Definitions<a class="copiable-link" href="#Definitions-1"> ¶</a></span></h2>
<p>These definitions are used throughout the remainder of this manual.
</p>
-<dl compact="compact">
-<dt id='index-POSIX'><span><code>POSIX</code><a href='#index-POSIX' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-POSIX"></a><span><code class="code">POSIX</code><a class="copiable-link" href="#index-POSIX"> ¶</a></span></dt>
<dd><p>A family of open system standards based on Unix. Bash
is primarily concerned with the Shell and Utilities portion of the
-<small>POSIX</small> 1003.1 standard.
+<small class="sc">POSIX</small> 1003.1 standard.
</p>
</dd>
-<dt><span><code>blank</code></span></dt>
+<dt><code class="code">blank</code></dt>
<dd><p>A space or tab character.
</p>
</dd>
-<dt id='index-builtin-1'><span><code>builtin</code><a href='#index-builtin-1' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-builtin-1"></a><span><code class="code">builtin</code><a class="copiable-link" href="#index-builtin-1"> ¶</a></span></dt>
<dd><p>A command that is implemented internally by the shell itself, rather
than by an executable program somewhere in the file system.
</p>
</dd>
-<dt id='index-control-operator'><span><code>control operator</code><a href='#index-control-operator' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A <code>token</code> that performs a control function. It is a <code>newline</code>
+<dt><a id="index-control-operator"></a><span><code class="code">control operator</code><a class="copiable-link" href="#index-control-operator"> ¶</a></span></dt>
+<dd><p>A <code class="code">token</code> that performs a control function. It is a <code class="code">newline</code>
or one of the following:
-‘<samp>||</samp>’, ‘<samp>&&</samp>’, ‘<samp>&</samp>’, ‘<samp>;</samp>’, ‘<samp>;;</samp>’, ‘<samp>;&</samp>’, ‘<samp>;;&</samp>’,
-‘<samp>|</samp>’, ‘<samp>|&</samp>’, ‘<samp>(</samp>’, or ‘<samp>)</samp>’.
+‘<samp class="samp">||</samp>’, ‘<samp class="samp">&&</samp>’, ‘<samp class="samp">&</samp>’, ‘<samp class="samp">;</samp>’, ‘<samp class="samp">;;</samp>’, ‘<samp class="samp">;&</samp>’, ‘<samp class="samp">;;&</samp>’,
+‘<samp class="samp">|</samp>’, ‘<samp class="samp">|&</samp>’, ‘<samp class="samp">(</samp>’, or ‘<samp class="samp">)</samp>’.
</p>
</dd>
-<dt id='index-exit-status'><span><code>exit status</code><a href='#index-exit-status' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-exit-status"></a><span><code class="code">exit status</code><a class="copiable-link" href="#index-exit-status"> ¶</a></span></dt>
<dd><p>The value returned by a command to its caller. The value is restricted
to eight bits, so the maximum value is 255.
</p>
</dd>
-<dt id='index-field'><span><code>field</code><a href='#index-field' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-field"></a><span><code class="code">field</code><a class="copiable-link" href="#index-field"> ¶</a></span></dt>
<dd><p>A unit of text that is the result of one of the shell expansions. After
expansion, when executing a command, the resulting fields are used as
the command name and arguments.
</p>
</dd>
-<dt id='index-filename'><span><code>filename</code><a href='#index-filename' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-filename"></a><span><code class="code">filename</code><a class="copiable-link" href="#index-filename"> ¶</a></span></dt>
<dd><p>A string of characters used to identify a file.
</p>
</dd>
-<dt id='index-job'><span><code>job</code><a href='#index-job' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-job"></a><span><code class="code">job</code><a class="copiable-link" href="#index-job"> ¶</a></span></dt>
<dd><p>A set of processes comprising a pipeline, and any processes descended
from it, that are all in the same process group.
</p>
</dd>
-<dt id='index-job-control'><span><code>job control</code><a href='#index-job-control' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-job-control"></a><span><code class="code">job control</code><a class="copiable-link" href="#index-job-control"> ¶</a></span></dt>
<dd><p>A mechanism by which users can selectively stop (suspend) and restart
(resume) execution of processes.
</p>
</dd>
-<dt id='index-metacharacter'><span><code>metacharacter</code><a href='#index-metacharacter' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-metacharacter"></a><span><code class="code">metacharacter</code><a class="copiable-link" href="#index-metacharacter"> ¶</a></span></dt>
<dd><p>A character that, when unquoted, separates words. A metacharacter is
-a <code>space</code>, <code>tab</code>, <code>newline</code>, or one of the following characters:
-‘<samp>|</samp>’, ‘<samp>&</samp>’, ‘<samp>;</samp>’, ‘<samp>(</samp>’, ‘<samp>)</samp>’, ‘<samp><</samp>’, or
-‘<samp>></samp>’.
+a <code class="code">space</code>, <code class="code">tab</code>, <code class="code">newline</code>, or one of the following characters:
+‘<samp class="samp">|</samp>’, ‘<samp class="samp">&</samp>’, ‘<samp class="samp">;</samp>’, ‘<samp class="samp">(</samp>’, ‘<samp class="samp">)</samp>’, ‘<samp class="samp"><</samp>’, or
+‘<samp class="samp">></samp>’.
</p>
</dd>
-<dt id='index-name'><span><code>name</code><a href='#index-name' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-identifier"></span>
-<p>A <code>word</code> consisting solely of letters, numbers, and underscores,
-and beginning with a letter or underscore. <code>Name</code>s are used as
+<dt><a class="index-entry-id" id="index-identifier"></a>
+<a id="index-name"></a><span><code class="code">name</code><a class="copiable-link" href="#index-name"> ¶</a></span></dt>
+<dd><p>A <code class="code">word</code> consisting solely of letters, numbers, and underscores,
+and beginning with a letter or underscore. <code class="code">Name</code>s are used as
shell variable and function names.
-Also referred to as an <code>identifier</code>.
+Also referred to as an <code class="code">identifier</code>.
</p>
</dd>
-<dt id='index-operator_002c-shell'><span><code>operator</code><a href='#index-operator_002c-shell' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A <code>control operator</code> or a <code>redirection operator</code>.
-See <a href="#Redirections">Redirections</a>, for a list of redirection operators.
-Operators contain at least one unquoted <code>metacharacter</code>.
+<dt><a id="index-operator_002c-shell"></a><span><code class="code">operator</code><a class="copiable-link" href="#index-operator_002c-shell"> ¶</a></span></dt>
+<dd><p>A <code class="code">control operator</code> or a <code class="code">redirection operator</code>.
+See <a class="xref" href="#Redirections">Redirections</a>, for a list of redirection operators.
+Operators contain at least one unquoted <code class="code">metacharacter</code>.
</p>
</dd>
-<dt id='index-process-group'><span><code>process group</code><a href='#index-process-group' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-process-group"></a><span><code class="code">process group</code><a class="copiable-link" href="#index-process-group"> ¶</a></span></dt>
<dd><p>A collection of related processes each having the same process
-group <small>ID</small>.
+group <small class="sc">ID</small>.
</p>
</dd>
-<dt id='index-process-group-ID'><span><code>process group ID</code><a href='#index-process-group-ID' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A unique identifier that represents a <code>process group</code>
+<dt><a id="index-process-group-ID"></a><span><code class="code">process group ID</code><a class="copiable-link" href="#index-process-group-ID"> ¶</a></span></dt>
+<dd><p>A unique identifier that represents a <code class="code">process group</code>
during its lifetime.
</p>
</dd>
-<dt id='index-reserved-word'><span><code>reserved word</code><a href='#index-reserved-word' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A <code>word</code> that has a special meaning to the shell. Most reserved
-words introduce shell flow control constructs, such as <code>for</code> and
-<code>while</code>.
+<dt><a id="index-reserved-word"></a><span><code class="code">reserved word</code><a class="copiable-link" href="#index-reserved-word"> ¶</a></span></dt>
+<dd><p>A <code class="code">word</code> that has a special meaning to the shell. Most reserved
+words introduce shell flow control constructs, such as <code class="code">for</code> and
+<code class="code">while</code>.
</p>
</dd>
-<dt id='index-return-status'><span><code>return status</code><a href='#index-return-status' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A synonym for <code>exit status</code>.
+<dt><a id="index-return-status"></a><span><code class="code">return status</code><a class="copiable-link" href="#index-return-status"> ¶</a></span></dt>
+<dd><p>A synonym for <code class="code">exit status</code>.
</p>
</dd>
-<dt id='index-signal'><span><code>signal</code><a href='#index-signal' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-signal"></a><span><code class="code">signal</code><a class="copiable-link" href="#index-signal"> ¶</a></span></dt>
<dd><p>A mechanism by which a process may be notified by the kernel
of an event occurring in the system.
</p>
</dd>
-<dt id='index-special-builtin'><span><code>special builtin</code><a href='#index-special-builtin' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-special-builtin"></a><span><code class="code">special builtin</code><a class="copiable-link" href="#index-special-builtin"> ¶</a></span></dt>
<dd><p>A shell builtin command that has been classified as special by the
-<small>POSIX</small> standard.
+<small class="sc">POSIX</small> standard.
</p>
</dd>
-<dt id='index-token'><span><code>token</code><a href='#index-token' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-token"></a><span><code class="code">token</code><a class="copiable-link" href="#index-token"> ¶</a></span></dt>
<dd><p>A sequence of characters considered a single unit by the shell.
-It is either a <code>word</code> or an <code>operator</code>.
+It is either a <code class="code">word</code> or an <code class="code">operator</code>.
</p>
</dd>
-<dt id='index-word'><span><code>word</code><a href='#index-word' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-word"></a><span><code class="code">word</code><a class="copiable-link" href="#index-word"> ¶</a></span></dt>
<dd><p>A sequence of characters treated as a unit by the shell.
-Words may not include unquoted <code>metacharacters</code>.
+Words may not include unquoted <code class="code">metacharacters</code>.
</p></dd>
</dl>
<hr>
</div>
-<div class="chapter" id="Basic-Shell-Features">
-<div class="header">
+<div class="chapter-level-extent" id="Basic-Shell-Features">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Builtin-Commands" accesskey="n" rel="next">Shell Builtin Commands</a>, Previous: <a href="#Definitions" accesskey="p" rel="prev">Definitions</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Basic-Shell-Features-1"></span><h2 class="chapter">3 Basic Shell Features</h2>
-<span id="index-Bourne-shell"></span>
+<h2 class="chapter" id="Basic-Shell-Features-1"><span>3 Basic Shell Features<a class="copiable-link" href="#Basic-Shell-Features-1"> ¶</a></span></h2>
+<a class="index-entry-id" id="index-Bourne-shell"></a>
-<p>Bash is an acronym for ‘<samp>Bourne-Again SHell</samp>’.
+<p>Bash is an acronym for ‘<samp class="samp">Bourne-Again SHell</samp>’.
The Bourne shell is
the traditional Unix shell originally written by Stephen Bourne.
All of the Bourne shell builtin commands are available in Bash,
-The rules for evaluation and quoting are taken from the <small>POSIX</small>
+The rules for evaluation and quoting are taken from the <small class="sc">POSIX</small>
specification for the ‘standard’ Unix shell.
</p>
<p>This chapter briefly summarizes the shell’s ‘building blocks’:
-commands, control structures, shell functions, shell <i>parameters</i>,
+commands, control structures, shell functions, shell <i class="i">parameters</i>,
shell expansions,
-<i>redirections</i>, which are a way to direct input and output from
+<i class="i">redirections</i>, which are a way to direct input and output from
and to named files, and how the shell executes commands.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Shell-Syntax" accesskey="1">Shell Syntax</a></li>
<li><a href="#Shell-Commands" accesskey="2">Shell Commands</a></li>
<li><a href="#Shell-Functions" accesskey="3">Shell Functions</a></li>
<li><a href="#Shell-Scripts" accesskey="8">Shell Scripts</a></li>
</ul>
<hr>
-<div class="section" id="Shell-Syntax">
-<div class="header">
+<div class="section-level-extent" id="Shell-Syntax">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Commands" accesskey="n" rel="next">Shell Commands</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Syntax-1"></span><h3 class="section">3.1 Shell Syntax</h3>
+<h3 class="section" id="Shell-Syntax-1"><span>3.1 Shell Syntax<a class="copiable-link" href="#Shell-Syntax-1"> ¶</a></span></h3>
<p>When the shell reads input, it proceeds through a
sequence of operations. If the input indicates the beginning of a
-comment, the shell ignores the comment symbol (‘<samp>#</samp>’), and the rest
+comment, the shell ignores the comment symbol (‘<samp class="samp">#</samp>’), and the rest
of that line.
</p>
<p>Otherwise, roughly speaking, the shell reads its input and
command, waits for the command’s exit status, and makes that exit status
available for further inspection or processing.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Shell-Operation" accesskey="1">Shell Operation</a></li>
<li><a href="#Quoting" accesskey="2">Quoting</a></li>
<li><a href="#Comments" accesskey="3">Comments</a></li>
</ul>
<hr>
-<div class="subsection" id="Shell-Operation">
-<div class="header">
+<div class="subsection-level-extent" id="Shell-Operation">
+<div class="nav-panel">
<p>
Next: <a href="#Quoting" accesskey="n" rel="next">Quoting</a>, Up: <a href="#Shell-Syntax" accesskey="u" rel="up">Shell Syntax</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Operation-1"></span><h4 class="subsection">3.1.1 Shell Operation</h4>
+<h4 class="subsection" id="Shell-Operation-1"><span>3.1.1 Shell Operation<a class="copiable-link" href="#Shell-Operation-1"> ¶</a></span></h4>
<p>The following is a brief description of the shell’s operation when it
reads and executes a command. Basically, the shell does the
following:
</p>
-<ol>
-<li> Reads its input from a file (see <a href="#Shell-Scripts">Shell Scripts</a>), from a string
-supplied as an argument to the <samp>-c</samp> invocation option
-(see <a href="#Invoking-Bash">Invoking Bash</a>), or from the user’s terminal.
+<ol class="enumerate">
+<li> Reads its input from a file (see <a class="pxref" href="#Shell-Scripts">Shell Scripts</a>), from a string
+supplied as an argument to the <samp class="option">-c</samp> invocation option
+(see <a class="pxref" href="#Invoking-Bash">Invoking Bash</a>), or from the user’s terminal.
</li><li> Breaks the input into words and operators, obeying the quoting rules
-described in <a href="#Quoting">Quoting</a>. These tokens are separated by
-<code>metacharacters</code>. Alias expansion is performed by this step
-(see <a href="#Aliases">Aliases</a>).
+described in <a class="ref" href="#Quoting">Quoting</a>. These tokens are separated by
+<code class="code">metacharacters</code>. Alias expansion is performed by this step
+(see <a class="pxref" href="#Aliases">Aliases</a>).
</li><li> Parses the tokens into simple and compound commands
-(see <a href="#Shell-Commands">Shell Commands</a>).
+(see <a class="pxref" href="#Shell-Commands">Shell Commands</a>).
-</li><li> Performs the various shell expansions (see <a href="#Shell-Expansions">Shell Expansions</a>), breaking
-the expanded tokens into lists of filenames (see <a href="#Filename-Expansion">Filename Expansion</a>)
+</li><li> Performs the various shell expansions (see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>), breaking
+the expanded tokens into lists of filenames (see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>)
and commands and arguments.
-</li><li> Performs any necessary redirections (see <a href="#Redirections">Redirections</a>) and removes
+</li><li> Performs any necessary redirections (see <a class="pxref" href="#Redirections">Redirections</a>) and removes
the redirection operators and their operands from the argument list.
-</li><li> Executes the command (see <a href="#Executing-Commands">Executing Commands</a>).
+</li><li> Executes the command (see <a class="pxref" href="#Executing-Commands">Executing Commands</a>).
</li><li> Optionally waits for the command to complete and collects its exit
-status (see <a href="#Exit-Status">Exit Status</a>).
+status (see <a class="pxref" href="#Exit-Status">Exit Status</a>).
</li></ol>
<hr>
</div>
-<div class="subsection" id="Quoting">
-<div class="header">
+<div class="subsection-level-extent" id="Quoting">
+<div class="nav-panel">
<p>
Next: <a href="#Comments" accesskey="n" rel="next">Comments</a>, Previous: <a href="#Shell-Operation" accesskey="p" rel="prev">Shell Operation</a>, Up: <a href="#Shell-Syntax" accesskey="u" rel="up">Shell Syntax</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Quoting-1"></span><h4 class="subsection">3.1.2 Quoting</h4>
-<span id="index-quoting"></span>
+<h4 class="subsection" id="Quoting-1"><span>3.1.2 Quoting<a class="copiable-link" href="#Quoting-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-quoting"></a>
<p>Quoting is used to remove the special meaning of certain
characters or words to the shell. Quoting can be used to
reserved words from being recognized as such, and to prevent
parameter expansion.
</p>
-<p>Each of the shell metacharacters (see <a href="#Definitions">Definitions</a>)
+<p>Each of the shell metacharacters (see <a class="pxref" href="#Definitions">Definitions</a>)
has special meaning to the shell and must be quoted if it is to
represent itself.
When the command history expansion facilities are being used
-(see <a href="#History-Interaction">History Expansion</a>), the
-<em>history expansion</em> character, usually ‘<samp>!</samp>’, must be quoted
-to prevent history expansion. See <a href="#Bash-History-Facilities">Bash History Facilities</a>, for
+(see <a class="pxref" href="#History-Interaction">History Expansion</a>), the
+<em class="dfn">history expansion</em> character, usually ‘<samp class="samp">!</samp>’, must be quoted
+to prevent history expansion. See <a class="xref" href="#Bash-History-Facilities">Bash History Facilities</a>, for
more details concerning history expansion.
</p>
<p>There are three quoting mechanisms: the
-<em>escape character</em>, single quotes, and double quotes.
+<em class="dfn">escape character</em>, single quotes, and double quotes.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Escape-Character" accesskey="1">Escape Character</a></li>
<li><a href="#Single-Quotes" accesskey="2">Single Quotes</a></li>
<li><a href="#Double-Quotes" accesskey="3">Double Quotes</a></li>
<li><a href="#Locale-Translation" accesskey="5">Locale-Specific Translation</a></li>
</ul>
<hr>
-<div class="subsubsection" id="Escape-Character">
-<div class="header">
+<div class="subsubsection-level-extent" id="Escape-Character">
+<div class="nav-panel">
<p>
Next: <a href="#Single-Quotes" accesskey="n" rel="next">Single Quotes</a>, Up: <a href="#Quoting" accesskey="u" rel="up">Quoting</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Escape-Character-1"></span><h4 class="subsubsection">3.1.2.1 Escape Character</h4>
-<p>A non-quoted backslash ‘<samp>\</samp>’ is the Bash escape character.
+<h4 class="subsubsection" id="Escape-Character-1"><span>3.1.2.1 Escape Character<a class="copiable-link" href="#Escape-Character-1"> ¶</a></span></h4>
+<p>A non-quoted backslash ‘<samp class="samp">\</samp>’ is the Bash escape character.
It preserves the literal value of the next character that follows,
-with the exception of <code>newline</code>. If a <code>\newline</code> pair
-appears, and the backslash itself is not quoted, the <code>\newline</code>
+with the exception of <code class="code">newline</code>. If a <code class="code">\newline</code> pair
+appears, and the backslash itself is not quoted, the <code class="code">\newline</code>
is treated as a line continuation (that is, it is removed from
the input stream and effectively ignored).
</p>
<hr>
</div>
-<div class="subsubsection" id="Single-Quotes">
-<div class="header">
+<div class="subsubsection-level-extent" id="Single-Quotes">
+<div class="nav-panel">
<p>
Next: <a href="#Double-Quotes" accesskey="n" rel="next">Double Quotes</a>, Previous: <a href="#Escape-Character" accesskey="p" rel="prev">Escape Character</a>, Up: <a href="#Quoting" accesskey="u" rel="up">Quoting</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Single-Quotes-1"></span><h4 class="subsubsection">3.1.2.2 Single Quotes</h4>
+<h4 class="subsubsection" id="Single-Quotes-1"><span>3.1.2.2 Single Quotes<a class="copiable-link" href="#Single-Quotes-1"> ¶</a></span></h4>
-<p>Enclosing characters in single quotes (‘<samp>'</samp>’) preserves the literal value
+<p>Enclosing characters in single quotes (‘<samp class="samp">'</samp>’) preserves the literal value
of each character within the quotes. A single quote may not occur
between single quotes, even when preceded by a backslash.
</p>
<hr>
</div>
-<div class="subsubsection" id="Double-Quotes">
-<div class="header">
+<div class="subsubsection-level-extent" id="Double-Quotes">
+<div class="nav-panel">
<p>
Next: <a href="#ANSI_002dC-Quoting" accesskey="n" rel="next">ANSI-C Quoting</a>, Previous: <a href="#Single-Quotes" accesskey="p" rel="prev">Single Quotes</a>, Up: <a href="#Quoting" accesskey="u" rel="up">Quoting</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Double-Quotes-1"></span><h4 class="subsubsection">3.1.2.3 Double Quotes</h4>
+<h4 class="subsubsection" id="Double-Quotes-1"><span>3.1.2.3 Double Quotes<a class="copiable-link" href="#Double-Quotes-1"> ¶</a></span></h4>
-<p>Enclosing characters in double quotes (‘<samp>"</samp>’) preserves the literal value
+<p>Enclosing characters in double quotes (‘<samp class="samp">"</samp>’) preserves the literal value
of all characters within the quotes, with the exception of
-‘<samp>$</samp>’, ‘<samp>`</samp>’, ‘<samp>\</samp>’,
-and, when history expansion is enabled, ‘<samp>!</samp>’.
+‘<samp class="samp">$</samp>’, ‘<samp class="samp">`</samp>’, ‘<samp class="samp">\</samp>’,
+and, when history expansion is enabled, ‘<samp class="samp">!</samp>’.
When the shell is in
-<small>POSIX</small> mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>),
-the ‘<samp>!</samp>’ has no special meaning
+<small class="sc">POSIX</small> mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>),
+the ‘<samp class="samp">!</samp>’ has no special meaning
within double quotes, even when history expansion is enabled.
-The characters ‘<samp>$</samp>’ and ‘<samp>`</samp>’
-retain their special meaning within double quotes (see <a href="#Shell-Expansions">Shell Expansions</a>).
+The characters ‘<samp class="samp">$</samp>’ and ‘<samp class="samp">`</samp>’
+retain their special meaning within double quotes (see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>).
The backslash retains its special meaning only when followed by one of
the following characters:
-‘<samp>$</samp>’, ‘<samp>`</samp>’, ‘<samp>"</samp>’, ‘<samp>\</samp>’, or <code>newline</code>.
+‘<samp class="samp">$</samp>’, ‘<samp class="samp">`</samp>’, ‘<samp class="samp">"</samp>’, ‘<samp class="samp">\</samp>’, or <code class="code">newline</code>.
Within double quotes, backslashes that are followed by one of these
characters are removed. Backslashes preceding characters without a
special meaning are left unmodified.
A double quote may be quoted within double quotes by preceding it with
a backslash.
-If enabled, history expansion will be performed unless an ‘<samp>!</samp>’
+If enabled, history expansion will be performed unless an ‘<samp class="samp">!</samp>’
appearing in double quotes is escaped using a backslash.
-The backslash preceding the ‘<samp>!</samp>’ is not removed.
+The backslash preceding the ‘<samp class="samp">!</samp>’ is not removed.
</p>
-<p>The special parameters ‘<samp>*</samp>’ and ‘<samp>@</samp>’ have special meaning
-when in double quotes (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+<p>The special parameters ‘<samp class="samp">*</samp>’ and ‘<samp class="samp">@</samp>’ have special meaning
+when in double quotes (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
</p>
<hr>
</div>
-<div class="subsubsection" id="ANSI_002dC-Quoting">
-<div class="header">
+<div class="subsubsection-level-extent" id="ANSI_002dC-Quoting">
+<div class="nav-panel">
<p>
Next: <a href="#Locale-Translation" accesskey="n" rel="next">Locale-Specific Translation</a>, Previous: <a href="#Double-Quotes" accesskey="p" rel="prev">Double Quotes</a>, Up: <a href="#Quoting" accesskey="u" rel="up">Quoting</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="ANSI_002dC-Quoting-1"></span><h4 class="subsubsection">3.1.2.4 ANSI-C Quoting</h4>
-<span id="index-quoting_002c-ANSI"></span>
+<h4 class="subsubsection" id="ANSI_002dC-Quoting-1"><span>3.1.2.4 ANSI-C Quoting<a class="copiable-link" href="#ANSI_002dC-Quoting-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-quoting_002c-ANSI"></a>
-<p>Character sequences of the form <code>$'<var>string</var>'</code> are treated as
+<p>Character sequences of the form <code class="code">$'<var class="var">string</var>'</code> are treated as
a special kind of single quotes.
-The sequence expands to <var>string</var>, with backslash-escaped characters
-in <var>string</var> replaced as specified by the ANSI C standard.
+The sequence expands to <var class="var">string</var>, with backslash-escaped characters
+in <var class="var">string</var> replaced as specified by the ANSI C standard.
Backslash escape sequences, if present, are decoded as follows:
</p>
-<dl compact="compact">
-<dt><span><code>\a</code></span></dt>
+<dl class="table">
+<dt><code class="code">\a</code></dt>
<dd><p>alert (bell)
</p></dd>
-<dt><span><code>\b</code></span></dt>
+<dt><code class="code">\b</code></dt>
<dd><p>backspace
</p></dd>
-<dt><span><code>\e</code></span></dt>
-<dt><span><code>\E</code></span></dt>
+<dt><code class="code">\e</code></dt>
+<dt><code class="code">\E</code></dt>
<dd><p>an escape character (not ANSI C)
</p></dd>
-<dt><span><code>\f</code></span></dt>
+<dt><code class="code">\f</code></dt>
<dd><p>form feed
</p></dd>
-<dt><span><code>\n</code></span></dt>
+<dt><code class="code">\n</code></dt>
<dd><p>newline
</p></dd>
-<dt><span><code>\r</code></span></dt>
+<dt><code class="code">\r</code></dt>
<dd><p>carriage return
</p></dd>
-<dt><span><code>\t</code></span></dt>
+<dt><code class="code">\t</code></dt>
<dd><p>horizontal tab
</p></dd>
-<dt><span><code>\v</code></span></dt>
+<dt><code class="code">\v</code></dt>
<dd><p>vertical tab
</p></dd>
-<dt><span><code>\\</code></span></dt>
+<dt><code class="code">\\</code></dt>
<dd><p>backslash
</p></dd>
-<dt><span><code>\'</code></span></dt>
+<dt><code class="code">\'</code></dt>
<dd><p>single quote
</p></dd>
-<dt><span><code>\"</code></span></dt>
+<dt><code class="code">\"</code></dt>
<dd><p>double quote
</p></dd>
-<dt><span><code>\?</code></span></dt>
+<dt><code class="code">\?</code></dt>
<dd><p>question mark
</p></dd>
-<dt><span><code>\<var>nnn</var></code></span></dt>
-<dd><p>the eight-bit character whose value is the octal value <var>nnn</var>
+<dt><code class="code">\<var class="var">nnn</var></code></dt>
+<dd><p>the eight-bit character whose value is the octal value <var class="var">nnn</var>
(one to three octal digits)
</p></dd>
-<dt><span><code>\x<var>HH</var></code></span></dt>
-<dd><p>the eight-bit character whose value is the hexadecimal value <var>HH</var>
+<dt><code class="code">\x<var class="var">HH</var></code></dt>
+<dd><p>the eight-bit character whose value is the hexadecimal value <var class="var">HH</var>
(one or two hex digits)
</p></dd>
-<dt><span><code>\u<var>HHHH</var></code></span></dt>
+<dt><code class="code">\u<var class="var">HHHH</var></code></dt>
<dd><p>the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
-<var>HHHH</var> (one to four hex digits)
+<var class="var">HHHH</var> (one to four hex digits)
</p></dd>
-<dt><span><code>\U<var>HHHHHHHH</var></code></span></dt>
+<dt><code class="code">\U<var class="var">HHHHHHHH</var></code></dt>
<dd><p>the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
-<var>HHHHHHHH</var> (one to eight hex digits)
+<var class="var">HHHHHHHH</var> (one to eight hex digits)
</p></dd>
-<dt><span><code>\c<var>x</var></code></span></dt>
-<dd><p>a control-<var>x</var> character
+<dt><code class="code">\c<var class="var">x</var></code></dt>
+<dd><p>a control-<var class="var">x</var> character
</p></dd>
</dl>
</p>
<hr>
</div>
-<div class="subsubsection" id="Locale-Translation">
-<div class="header">
+<div class="subsubsection-level-extent" id="Locale-Translation">
+<div class="nav-panel">
<p>
Previous: <a href="#ANSI_002dC-Quoting" accesskey="p" rel="prev">ANSI-C Quoting</a>, Up: <a href="#Quoting" accesskey="u" rel="up">Quoting</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Locale_002dSpecific-Translation"></span><h4 class="subsubsection">3.1.2.5 Locale-Specific Translation</h4>
-<span id="index-localization"></span>
-<span id="index-internationalization"></span>
-<span id="index-native-languages"></span>
-<span id="index-translation_002c-native-languages"></span>
+<h4 class="subsubsection" id="Locale_002dSpecific-Translation"><span>3.1.2.5 Locale-Specific Translation<a class="copiable-link" href="#Locale_002dSpecific-Translation"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-localization"></a>
+<a class="index-entry-id" id="index-internationalization"></a>
+<a class="index-entry-id" id="index-native-languages"></a>
+<a class="index-entry-id" id="index-translation_002c-native-languages"></a>
-<p>Prefixing a double-quoted string with a dollar sign (‘<samp>$</samp>’), such
-as <tt>$"hello, world"</tt>,
+<p>Prefixing a double-quoted string with a dollar sign (‘<samp class="samp">$</samp>’), such
+as <code class="verb">$"hello, world"</code>,
will cause the string to be translated according to the current locale.
-The <code>gettext</code> infrastructure performs the lookup and
-translation, using the <code>LC_MESSAGES</code>, <code>TEXTDOMAINDIR</code>,
-and <code>TEXTDOMAIN</code> shell variables, as explained below.
+The <code class="code">gettext</code> infrastructure performs the lookup and
+translation, using the <code class="code">LC_MESSAGES</code>, <code class="code">TEXTDOMAINDIR</code>,
+and <code class="code">TEXTDOMAIN</code> shell variables, as explained below.
See the gettext documentation for additional details not covered here.
-If the current locale is <code>C</code> or <code>POSIX</code>,
+If the current locale is <code class="code">C</code> or <code class="code">POSIX</code>,
if there are no translations available,
of if the string is not translated,
the dollar sign is ignored.
Since this is a form of double quoting, the string remains double-quoted
by default, whether or not it is translated and replaced.
-If the <code>noexpand_translation</code> option is enabled
-using the <code>shopt</code> builtin (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>),
+If the <code class="code">noexpand_translation</code> option is enabled
+using the <code class="code">shopt</code> builtin (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>),
translated strings are single-quoted instead of double-quoted.
</p>
<p>The rest of this section is a brief overview of how you use gettext to
-create translations for strings in a shell script named <var>scriptname</var>.
+create translations for strings in a shell script named <var class="var">scriptname</var>.
There are more details in the gettext documentation.
</p>
<hr>
-<span id="Creating-Internationalized-Scripts"></span><div class="header">
+<a class="node-id" id="Creating-Internationalized-Scripts"></a><div class="nav-panel">
<p>
-
[<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
+[<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<h4 class="node-heading">Creating Internationalized Scripts</h4>
-<span id="index-internationalized-scripts"></span>
-<span id="index-string-translations"></span>
+<h4 class="node"><span>Creating Internationalized Scripts<a class="copiable-link" href="#Creating-Internationalized-Scripts"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-internationalized-scripts"></a>
+<a class="index-entry-id" id="index-string-translations"></a>
<p>Once you’ve marked the strings in your script
that you want to translate using $"...",
you create a gettext "template" file using the command
</p>
<div class="example">
-<pre class="example">bash --dump-po-strings <var>scriptname</var> > <var>domain</var>.pot
+<pre class="example-preformatted">bash --dump-po-strings <var class="var">scriptname</var> > <var class="var">domain</var>.pot
</pre></div>
-<p>The <var>domain</var> is your <em>message domain</em>.
+<p>The <var class="var">domain</var> is your <em class="dfn">message domain</em>.
It’s just an arbitrary string that’s used to identify the files gettext
needs, like a package or script name.
It needs to be unique among all
the message domains on systems where you install the translations, so
gettext knows which translations correspond to your script.
You’ll use the template file to create translations for each target language.
-The template file conventionally has the suffix ‘<samp>.pot</samp>’.
+The template file conventionally has the suffix ‘<samp class="samp">.pot</samp>’.
</p>
<p>You copy this template file to a separate file for each target language
-you want to support (called "PO" files, which use the suffix ‘<samp>.po</samp>’).
+you want to support (called "PO" files, which use the suffix ‘<samp class="samp">.po</samp>’).
PO files use various naming conventions, but
when you are working to translate a template file into a particular
language, you first copy the template file to a file whose name is the
-language you want to target, with the ‘<samp>.po</samp>’ suffix.
+language you want to target, with the ‘<samp class="samp">.po</samp>’ suffix.
For instance, the Spanish translations of your strings would be
-in a file named ‘<samp>es.po</samp>’, and to get started using a message
+in a file named ‘<samp class="samp">es.po</samp>’, and to get started using a message
domain named "example," you would run
</p>
<div class="example">
-<pre class="example">cp example.pot es.po
+<pre class="example-preformatted">cp example.pot es.po
</pre></div>
-<p>Ultimately, PO files are often named <var>domain</var>.po and installed in
+<p>Ultimately, PO files are often named <var class="var">domain</var>.po and installed in
directories that contain multiple translation files for a particular language.
</p>
<p>Whichever naming convention you choose, you will need to translate the
versions of the PO files the gettext tools use to look up translations
efficiently.
MO files are also called "message catalog" files.
-You use the <code>msgfmt</code> program to do this.
+You use the <code class="command">msgfmt</code> program to do this.
For instance, if you had a file with Spanish translations, you could run
</p>
<div class="example">
-<pre class="example">msgfmt -o es.mo es.po
+<pre class="example-preformatted">msgfmt -o es.mo es.po
</pre></div>
<p>to produce the corresponding MO file.
</p>
<p>Once you have the MO files, you decide where to install them and use the
-<code>TEXTDOMAINDIR</code> shell variable to tell the gettext tools where they are.
+<code class="code">TEXTDOMAINDIR</code> shell variable to tell the gettext tools where they are.
Make sure to use the same message domain to name the MO files
as you did for the PO files when you install them.
</p>
-<span id="index-LANG"></span>
-<span id="index-LC_005fMESSAGES"></span>
-<span id="index-TEXTDOMAIN"></span>
-<span id="index-TEXTDOMAINDIR"></span>
-<p>Your users will use the <code>LANG</code> or <code>LC_MESSAGES</code> shell variables to
+<a class="index-entry-id" id="index-LANG"></a>
+<a class="index-entry-id" id="index-LC_005fMESSAGES"></a>
+<a class="index-entry-id" id="index-TEXTDOMAIN"></a>
+<a class="index-entry-id" id="index-TEXTDOMAINDIR"></a>
+<p>Your users will use the <code class="env">LANG</code> or <code class="env">LC_MESSAGES</code> shell variables to
select the desired language.
</p>
-<p>You set the <code>TEXTDOMAIN</code> variable to the script’s message domain.
+<p>You set the <code class="env">TEXTDOMAIN</code> variable to the script’s message domain.
As above, you use the message domain to name your translation files.
</p>
-<p>You, or possibly your users, set the <code>TEXTDOMAINDIR</code> variable to the
+<p>You, or possibly your users, set the <code class="env">TEXTDOMAINDIR</code> variable to the
name of a directory where the message catalog files are stored.
If you install the message files into the system’s standard message catalog
directory, you don’t need to worry about this variable.
</p>
<p>The directory where the message catalog files are stored varies between
systems.
-Some use the message catalog selected by the <code>LC_MESSAGES</code>
+Some use the message catalog selected by the <code class="env">LC_MESSAGES</code>
shell variable.
Others create the name of the message catalog from the value of the
-<code>TEXTDOMAIN</code> shell variable, possibly adding the ‘<samp>.mo</samp>’ suffix.
-If you use the <code>TEXTDOMAIN</code> variable, you may need to set the
-<code>TEXTDOMAINDIR</code> variable to the location of the message catalog files,
+<code class="env">TEXTDOMAIN</code> shell variable, possibly adding the ‘<samp class="samp">.mo</samp>’ suffix.
+If you use the <code class="env">TEXTDOMAIN</code> variable, you may need to set the
+<code class="env">TEXTDOMAINDIR</code> variable to the location of the message catalog files,
as above.
It’s common to use both variables in this fashion:
-<code>$TEXTDOMAINDIR</code>/<code>$LC_MESSAGES</code>/LC_MESSAGES/<code>$TEXTDOMAIN</code>.mo.
+<code class="env">$TEXTDOMAINDIR</code>/<code class="env">$LC_MESSAGES</code>/LC_MESSAGES/<code class="env">$TEXTDOMAIN</code>.mo.
</p>
<p>If you used that last convention, and you wanted to store the message
catalog files with Spanish (es) and Esperanto (eo) translations into a
local directory you use for custom translation files, you could run
</p>
<div class="example">
-<pre class="example">TEXTDOMAIN=example
+<pre class="example-preformatted">TEXTDOMAIN=example
TEXTDOMAINDIR=/usr/local/share/locale
cp es.mo ${TEXTDOMAINDIR}/es/LC_MESSAGES/${TEXTDOMAIN}.mo
<p>When all of this is done, and the message catalog files containing the
compiled translations are installed in the correct location,
your users will be able to see translated strings
-in any of the supported languages by setting the <code>LANG</code> or
-<code>LC_MESSAGES</code> environment variables before running your script.
+in any of the supported languages by setting the <code class="env">LANG</code> or
+<code class="env">LC_MESSAGES</code> environment variables before running your script.
</p>
<hr>
</div>
</div>
-<div class="subsection" id="Comments">
-<div class="header">
+<div class="subsection-level-extent" id="Comments">
+<div class="nav-panel">
<p>
Previous: <a href="#Quoting" accesskey="p" rel="prev">Quoting</a>, Up: <a href="#Shell-Syntax" accesskey="u" rel="up">Shell Syntax</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Comments-1"></span><h4 class="subsection">3.1.3 Comments</h4>
-<span id="index-comments_002c-shell"></span>
+<h4 class="subsection" id="Comments-1"><span>3.1.3 Comments<a class="copiable-link" href="#Comments-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-comments_002c-shell"></a>
<p>In a non-interactive shell, or an interactive shell in which the
-<code>interactive_comments</code> option to the <code>shopt</code>
-builtin is enabled (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>),
-a word beginning with ‘<samp>#</samp>’
+<code class="code">interactive_comments</code> option to the <code class="code">shopt</code>
+builtin is enabled (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>),
+a word beginning with ‘<samp class="samp">#</samp>’
causes that word and all remaining characters on that line to
-be ignored. An interactive shell without the <code>interactive_comments</code>
-option enabled does not allow comments. The <code>interactive_comments</code>
+be ignored. An interactive shell without the <code class="code">interactive_comments</code>
+option enabled does not allow comments. The <code class="code">interactive_comments</code>
option is on by default in interactive shells.
-See <a href="#Interactive-Shells">Interactive Shells</a>, for a description of what makes
+See <a class="xref" href="#Interactive-Shells">Interactive Shells</a>, for a description of what makes
a shell interactive.
</p>
<hr>
</div>
</div>
-<div class="section" id="Shell-Commands">
-<div class="header">
+<div class="section-level-extent" id="Shell-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Functions" accesskey="n" rel="next">Shell Functions</a>, Previous: <a href="#Shell-Syntax" accesskey="p" rel="prev">Shell Syntax</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Commands-1"></span><h3 class="section">3.2 Shell Commands</h3>
-<span id="index-commands_002c-shell"></span>
+<h3 class="section" id="Shell-Commands-1"><span>3.2 Shell Commands<a class="copiable-link" href="#Shell-Commands-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-commands_002c-shell"></a>
-<p>A simple shell command such as <code>echo a b c</code> consists of the command
+<p>A simple shell command such as <code class="code">echo a b c</code> consists of the command
itself followed by arguments, separated by spaces.
</p>
<p>More complex shell commands are composed of simple commands arranged together
some other grouping.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Reserved-Words" accesskey="1">Reserved Words</a></li>
<li><a href="#Simple-Commands" accesskey="2">Simple Commands</a></li>
<li><a href="#Pipelines" accesskey="3">Pipelines</a></li>
<li><a href="#GNU-Parallel" accesskey="7">GNU Parallel</a></li>
</ul>
<hr>
-<div class="subsection" id="Reserved-Words">
-<div class="header">
+<div class="subsection-level-extent" id="Reserved-Words">
+<div class="nav-panel">
<p>
Next: <a href="#Simple-Commands" accesskey="n" rel="next">Simple Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Reserved-Words-1"></span><h4 class="subsection">3.2.1 Reserved Words</h4>
-<span id="index-reserved-words"></span>
+<h4 class="subsection" id="Reserved-Words-1"><span>3.2.1 Reserved Words<a class="copiable-link" href="#Reserved-Words-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-reserved-words"></a>
<p>Reserved words are words that have special meaning to the shell.
They are used to begin and end the shell’s compound commands.
<p>The following words are recognized as reserved when unquoted and
the first word of a command (see below for exceptions):
</p>
-<table>
-<tr><td width="10%"><code>if</code></td><td width="10%"><code>then</code></td><td width="10%"><code>elif</code></td><td width="10%"><code>else</code></td><td width="12%"><code>fi</code></td><td width="10%"><code>time</code></td></tr>
-<tr><td width="10%"><code>for</code></td><td width="10%"><code>in</code></td><td width="10%"><code>until</code></td><td width="10%"><code>while</code></td><td width="12%"><code>do</code></td><td width="10%"><code>done</code></td></tr>
-<tr><td width="10%"><code>case</code></td><td width="10%"><code>esac</code></td><td width="10%"><code>coproc</code></td><td width="10%"><code>select</code></td><td width="12%"><code>function</code></td></tr>
-<tr><td width="10%"><code>{</code></td><td width="10%"><code>}</code></td><td width="10%"><code>[[</code></td><td width="10%"><code>]]</code></td><td width="12%"><code>!</code></td></tr>
+<table class="multitable">
+<tbody><tr><td width="10%"><code class="code">if</code></td><td width="10%"><code class="code">then</code></td><td width="10%"><code class="code">elif</code></td><td width="10%"><code class="code">else</code></td><td width="12%"><code class="code">fi</code></td><td width="10%"><code class="code">time</code></td></tr>
+<tr><td width="10%"><code class="code">for</code></td><td width="10%"><code class="code">in</code></td><td width="10%"><code class="code">until</code></td><td width="10%"><code class="code">while</code></td><td width="12%"><code class="code">do</code></td><td width="10%"><code class="code">done</code></td></tr>
+<tr><td width="10%"><code class="code">case</code></td><td width="10%"><code class="code">esac</code></td><td width="10%"><code class="code">coproc</code></td><td width="10%"><code class="code">select</code></td><td width="12%"><code class="code">function</code></td></tr>
+<tr><td width="10%"><code class="code">{</code></td><td width="10%"><code class="code">}</code></td><td width="10%"><code class="code">[[</code></td><td width="10%"><code class="code">]]</code></td><td width="12%"><code class="code">!</code></td></tr>
+</tbody>
</table>
-<p><code>in</code> is recognized as a reserved word if it is the third word of a
-<code>case</code> or <code>select</code> command.
-<code>in</code> and <code>do</code> are recognized as reserved
-words if they are the third word in a <code>for</code> command.
+<p><code class="code">in</code> is recognized as a reserved word if it is the third word of a
+<code class="code">case</code> or <code class="code">select</code> command.
+<code class="code">in</code> and <code class="code">do</code> are recognized as reserved
+words if they are the third word in a <code class="code">for</code> command.
</p>
<hr>
</div>
-<div class="subsection" id="Simple-Commands">
-<div class="header">
+<div class="subsection-level-extent" id="Simple-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Pipelines" accesskey="n" rel="next">Pipelines</a>, Previous: <a href="#Reserved-Words" accesskey="p" rel="prev">Reserved Words</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Simple-Commands-1"></span><h4 class="subsection">3.2.2 Simple Commands</h4>
-<span id="index-commands_002c-simple"></span>
+<h4 class="subsection" id="Simple-Commands-1"><span>3.2.2 Simple Commands<a class="copiable-link" href="#Simple-Commands-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-commands_002c-simple"></a>
<p>A simple command is the kind of command encountered most often.
-It’s just a sequence of words separated by <code>blank</code>s, terminated
-by one of the shell’s control operators (see <a href="#Definitions">Definitions</a>). The
+It’s just a sequence of words separated by <code class="code">blank</code>s, terminated
+by one of the shell’s control operators (see <a class="pxref" href="#Definitions">Definitions</a>). The
first word generally specifies a command to be executed, with the
rest of the words being that command’s arguments.
</p>
-<p>The return status (see <a href="#Exit-Status">Exit Status</a>) of a simple command is
+<p>The return status (see <a class="pxref" href="#Exit-Status">Exit Status</a>) of a simple command is
its exit status as provided
-by the <small>POSIX</small> 1003.1 <code>waitpid</code> function, or 128+<var>n</var> if
-the command was terminated by signal <var>n</var>.
+by the <small class="sc">POSIX</small> 1003.1 <code class="code">waitpid</code> function, or 128+<var class="var">n</var> if
+the command was terminated by signal <var class="var">n</var>.
</p>
<hr>
</div>
-<div class="subsection" id="Pipelines">
-<div class="header">
+<div class="subsection-level-extent" id="Pipelines">
+<div class="nav-panel">
<p>
Next: <a href="#Lists" accesskey="n" rel="next">Lists of Commands</a>, Previous: <a href="#Simple-Commands" accesskey="p" rel="prev">Simple Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Pipelines-1"></span><h4 class="subsection">3.2.3 Pipelines</h4>
-<span id="index-pipeline"></span>
-<span id="index-commands_002c-pipelines"></span>
+<h4 class="subsection" id="Pipelines-1"><span>3.2.3 Pipelines<a class="copiable-link" href="#Pipelines-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-pipeline"></a>
+<a class="index-entry-id" id="index-commands_002c-pipelines"></a>
-<p>A <code>pipeline</code> is a sequence of one or more commands separated by
-one of the control operators ‘<samp>|</samp>’ or ‘<samp>|&</samp>’.
+<p>A <code class="code">pipeline</code> is a sequence of one or more commands separated by
+one of the control operators ‘<samp class="samp">|</samp>’ or ‘<samp class="samp">|&</samp>’.
</p>
-<span id="index-time"></span>
-<span id="index-_0021"></span>
-<span id="index-command-timing"></span>
+<a class="index-entry-id" id="index-time"></a>
+<a class="index-entry-id" id="index-_0021"></a>
+<a class="index-entry-id" id="index-command-timing"></a>
<p>The format for a pipeline is
</p><div class="example">
-<pre class="example">[time [-p]] [!] <var>command1</var> [ | or |& <var>command2</var> ] …
+<pre class="example-preformatted">[time [-p]] [!] <var class="var">command1</var> [ | or |& <var class="var">command2</var> ] ...
</pre></div>
<p>The output of each command in the pipeline is connected via a pipe
to the input of the next command.
That is, each command reads the previous command’s output. This
connection is performed before any redirections specified by
-<var>command1</var>.
+<var class="var">command1</var>.
</p>
-<p>If ‘<samp>|&</samp>’ is used, <var>command1</var>’s standard error, in addition to
+<p>If ‘<samp class="samp">|&</samp>’ is used, <var class="var">command1</var>’s standard error, in addition to
its standard output, is connected to
-<var>command2</var>’s standard input through the pipe;
-it is shorthand for <code>2>&1 |</code>.
+<var class="var">command2</var>’s standard input through the pipe;
+it is shorthand for <code class="code">2>&1 |</code>.
This implicit redirection of the standard error to the standard output is
-performed after any redirections specified by <var>command1</var>.
+performed after any redirections specified by <var class="var">command1</var>.
</p>
-<p>The reserved word <code>time</code> causes timing statistics
+<p>The reserved word <code class="code">time</code> causes timing statistics
to be printed for the pipeline once it finishes.
The statistics currently consist of elapsed (wall-clock) time and
user and system time consumed by the command’s execution.
-The <samp>-p</samp> option changes the output format to that specified
-by <small>POSIX</small>.
-When the shell is in <small>POSIX</small> mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>),
-it does not recognize <code>time</code> as a reserved word if the next
-token begins with a ‘<samp>-</samp>’.
-The <code>TIMEFORMAT</code> variable may be set to a format string that
+The <samp class="option">-p</samp> option changes the output format to that specified
+by <small class="sc">POSIX</small>.
+When the shell is in <small class="sc">POSIX</small> mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>),
+it does not recognize <code class="code">time</code> as a reserved word if the next
+token begins with a ‘<samp class="samp">-</samp>’.
+The <code class="env">TIMEFORMAT</code> variable may be set to a format string that
specifies how the timing information should be displayed.
-See <a href="#Bash-Variables">Bash Variables</a>, for a description of the available formats.
-The use of <code>time</code> as a reserved word permits the timing of
+See <a class="xref" href="#Bash-Variables">Bash Variables</a>, for a description of the available formats.
+The use of <code class="code">time</code> as a reserved word permits the timing of
shell builtins, shell functions, and pipelines. An external
-<code>time</code> command cannot time these easily.
+<code class="code">time</code> command cannot time these easily.
</p>
-<p>When the shell is in <small>POSIX</small> mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>), <code>time</code>
+<p>When the shell is in <small class="sc">POSIX</small> mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>), <code class="code">time</code>
may be followed by a newline. In this case, the shell displays the
total user and system time consumed by the shell and its children.
-The <code>TIMEFORMAT</code> variable specifies the format of the time information.
+The <code class="env">TIMEFORMAT</code> variable specifies the format of the time information.
</p>
-<p>If the pipeline is not executed asynchronously (see <a href="#Lists">Lists of Commands</a>), the
+<p>If the pipeline is not executed asynchronously (see <a class="pxref" href="#Lists">Lists of Commands</a>), the
shell waits for all commands in the pipeline to complete.
</p>
<p>Each command in a multi-command pipeline,
where pipes are created,
-is executed in its own <em>subshell</em>, which is a
-separate process (see <a href="#Command-Execution-Environment">Command Execution Environment</a>).
-If the <code>lastpipe</code> option is enabled using the <code>shopt</code> builtin
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>),
+is executed in its own <em class="dfn">subshell</em>, which is a
+separate process (see <a class="pxref" href="#Command-Execution-Environment">Command Execution Environment</a>).
+If the <code class="code">lastpipe</code> option is enabled using the <code class="code">shopt</code> builtin
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>),
the last element of a pipeline may be run by the shell process
when job control is not active.
</p>
<p>The exit
status of a pipeline is the exit status of the last command in the
-pipeline, unless the <code>pipefail</code> option is enabled
-(see <a href="#The-Set-Builtin">The Set Builtin</a>).
-If <code>pipefail</code> is enabled, the pipeline’s return status is the
+pipeline, unless the <code class="code">pipefail</code> option is enabled
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
+If <code class="code">pipefail</code> is enabled, the pipeline’s return status is the
value of the last (rightmost) command to exit with a non-zero status,
or zero if all commands exit successfully.
-If the reserved word ‘<samp>!</samp>’ precedes the pipeline, the
+If the reserved word ‘<samp class="samp">!</samp>’ precedes the pipeline, the
exit status is the logical negation of the exit status as described
above.
The shell waits for all commands in the pipeline to terminate before
</p>
<hr>
</div>
-<div class="subsection" id="Lists">
-<div class="header">
+<div class="subsection-level-extent" id="Lists">
+<div class="nav-panel">
<p>
Next: <a href="#Compound-Commands" accesskey="n" rel="next">Compound Commands</a>, Previous: <a href="#Pipelines" accesskey="p" rel="prev">Pipelines</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Lists-of-Commands"></span><h4 class="subsection">3.2.4 Lists of Commands</h4>
-<span id="index-commands_002c-lists"></span>
+<h4 class="subsection" id="Lists-of-Commands"><span>3.2.4 Lists of Commands<a class="copiable-link" href="#Lists-of-Commands"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-commands_002c-lists"></a>
-<p>A <code>list</code> is a sequence of one or more pipelines separated by one
-of the operators ‘<samp>;</samp>’, ‘<samp>&</samp>’, ‘<samp>&&</samp>’, or ‘<samp>||</samp>’,
-and optionally terminated by one of ‘<samp>;</samp>’, ‘<samp>&</samp>’, or a
-<code>newline</code>.
+<p>A <code class="code">list</code> is a sequence of one or more pipelines separated by one
+of the operators ‘<samp class="samp">;</samp>’, ‘<samp class="samp">&</samp>’, ‘<samp class="samp">&&</samp>’, or ‘<samp class="samp">||</samp>’,
+and optionally terminated by one of ‘<samp class="samp">;</samp>’, ‘<samp class="samp">&</samp>’, or a
+<code class="code">newline</code>.
</p>
-<p>Of these list operators, ‘<samp>&&</samp>’ and ‘<samp>||</samp>’
-have equal precedence, followed by ‘<samp>;</samp>’ and ‘<samp>&</samp>’,
+<p>Of these list operators, ‘<samp class="samp">&&</samp>’ and ‘<samp class="samp">||</samp>’
+have equal precedence, followed by ‘<samp class="samp">;</samp>’ and ‘<samp class="samp">&</samp>’,
which have equal precedence.
</p>
-<p>A sequence of one or more newlines may appear in a <code>list</code>
+<p>A sequence of one or more newlines may appear in a <code class="code">list</code>
to delimit commands, equivalent to a semicolon.
</p>
-<p>If a command is terminated by the control operator ‘<samp>&</samp>’,
+<p>If a command is terminated by the control operator ‘<samp class="samp">&</samp>’,
the shell executes the command asynchronously in a subshell.
-This is known as executing the command in the <em>background</em>,
-and these are referred to as <em>asynchronous</em> commands.
+This is known as executing the command in the <em class="dfn">background</em>,
+and these are referred to as <em class="dfn">asynchronous</em> commands.
The shell does not wait for the command to finish, and the return
status is 0 (true).
-When job control is not active (see <a href="#Job-Control">Job Control</a>),
+When job control is not active (see <a class="pxref" href="#Job-Control">Job Control</a>),
the standard input for asynchronous commands, in the absence of any
-explicit redirections, is redirected from <code>/dev/null</code>.
+explicit redirections, is redirected from <code class="code">/dev/null</code>.
</p>
-<p>Commands separated by a ‘<samp>;</samp>’ are executed sequentially; the shell
+<p>Commands separated by a ‘<samp class="samp">;</samp>’ are executed sequentially; the shell
waits for each command to terminate in turn. The return status is the
exit status of the last command executed.
</p>
-<p><small>AND</small> and <small>OR</small> lists are sequences of one or more pipelines
-separated by the control operators ‘<samp>&&</samp>’ and ‘<samp>||</samp>’,
-respectively. <small>AND</small> and <small>OR</small> lists are executed with left
+<p><small class="sc">AND</small> and <small class="sc">OR</small> lists are sequences of one or more pipelines
+separated by the control operators ‘<samp class="samp">&&</samp>’ and ‘<samp class="samp">||</samp>’,
+respectively. <small class="sc">AND</small> and <small class="sc">OR</small> lists are executed with left
associativity.
</p>
-<p>An <small>AND</small> list has the form
+<p>An <small class="sc">AND</small> list has the form
</p><div class="example">
-<pre class="example"><var>command1</var> && <var>command2</var>
+<pre class="example-preformatted"><var class="var">command1</var> && <var class="var">command2</var>
</pre></div>
-<p><var>command2</var> is executed if, and only if, <var>command1</var>
+<p><var class="var">command2</var> is executed if, and only if, <var class="var">command1</var>
returns an exit status of zero (success).
</p>
-<p>An <small>OR</small> list has the form
+<p>An <small class="sc">OR</small> list has the form
</p><div class="example">
-<pre class="example"><var>command1</var> || <var>command2</var>
+<pre class="example-preformatted"><var class="var">command1</var> || <var class="var">command2</var>
</pre></div>
-<p><var>command2</var> is executed if, and only if, <var>command1</var>
+<p><var class="var">command2</var> is executed if, and only if, <var class="var">command1</var>
returns a non-zero exit status.
</p>
<p>The return status of
-<small>AND</small> and <small>OR</small> lists is the exit status of the last command
+<small class="sc">AND</small> and <small class="sc">OR</small> lists is the exit status of the last command
executed in the list.
</p>
<hr>
</div>
-<div class="subsection" id="Compound-Commands">
-<div class="header">
+<div class="subsection-level-extent" id="Compound-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Coprocesses" accesskey="n" rel="next">Coprocesses</a>, Previous: <a href="#Lists" accesskey="p" rel="prev">Lists of Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Compound-Commands-1"></span><h4 class="subsection">3.2.5 Compound Commands</h4>
-<span id="index-commands_002c-compound"></span>
+<h4 class="subsection" id="Compound-Commands-1"><span>3.2.5 Compound Commands<a class="copiable-link" href="#Compound-Commands-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-commands_002c-compound"></a>
<p>Compound commands are the shell programming language constructs.
Each construct begins with a reserved word or control operator and is
terminated by a corresponding reserved word or operator.
-Any redirections (see <a href="#Redirections">Redirections</a>) associated with a compound command
+Any redirections (see <a class="pxref" href="#Redirections">Redirections</a>) associated with a compound command
apply to all commands within that compound command unless explicitly overridden.
</p>
<p>In most cases a list of commands in a compound command’s description may be
<p>Bash provides looping constructs, conditional commands, and mechanisms
to group commands and execute them as a unit.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Looping-Constructs" accesskey="1">Looping Constructs</a></li>
<li><a href="#Conditional-Constructs" accesskey="2">Conditional Constructs</a></li>
<li><a href="#Command-Grouping" accesskey="3">Grouping Commands</a></li>
</ul>
<hr>
-<div class="subsubsection" id="Looping-Constructs">
-<div class="header">
+<div class="subsubsection-level-extent" id="Looping-Constructs">
+<div class="nav-panel">
<p>
Next: <a href="#Conditional-Constructs" accesskey="n" rel="next">Conditional Constructs</a>, Up: <a href="#Compound-Commands" accesskey="u" rel="up">Compound Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Looping-Constructs-1"></span><h4 class="subsubsection">3.2.5.1 Looping Constructs</h4>
-<span id="index-commands_002c-looping"></span>
+<h4 class="subsubsection" id="Looping-Constructs-1"><span>3.2.5.1 Looping Constructs<a class="copiable-link" href="#Looping-Constructs-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-commands_002c-looping"></a>
<p>Bash supports the following looping constructs.
</p>
-<p>Note that wherever a ‘<samp>;</samp>’ appears in the description of a
+<p>Note that wherever a ‘<samp class="samp">;</samp>’ appears in the description of a
command’s syntax, it may be replaced with one or more newlines.
</p>
-<dl compact="compact">
-<dt id='index-until'><span><code>until</code><a href='#index-until' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-do"></span>
-<span id="index-done"></span>
-<p>The syntax of the <code>until</code> command is:
+<dl class="table">
+<dt><a class="index-entry-id" id="index-do"></a>
+<a class="index-entry-id" id="index-done"></a>
+<a id="index-until"></a><span><code class="code">until</code><a class="copiable-link" href="#index-until"> ¶</a></span></dt>
+<dd><p>The syntax of the <code class="code">until</code> command is:
</p>
<div class="example">
-<pre class="example">until <var>test-commands</var>; do <var>consequent-commands</var>; done
+<pre class="example-preformatted">until <var class="var">test-commands</var>; do <var class="var">consequent-commands</var>; done
</pre></div>
-<p>Execute <var>consequent-commands</var> as long as
-<var>test-commands</var> has an exit status which is not zero.
+<p>Execute <var class="var">consequent-commands</var> as long as
+<var class="var">test-commands</var> has an exit status which is not zero.
The return status is the exit status of the last command executed
-in <var>consequent-commands</var>, or zero if none was executed.
+in <var class="var">consequent-commands</var>, or zero if none was executed.
</p>
</dd>
-<dt id='index-while'><span><code>while</code><a href='#index-while' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The syntax of the <code>while</code> command is:
+<dt><a id="index-while"></a><span><code class="code">while</code><a class="copiable-link" href="#index-while"> ¶</a></span></dt>
+<dd><p>The syntax of the <code class="code">while</code> command is:
</p>
<div class="example">
-<pre class="example">while <var>test-commands</var>; do <var>consequent-commands</var>; done
+<pre class="example-preformatted">while <var class="var">test-commands</var>; do <var class="var">consequent-commands</var>; done
</pre></div>
-<p>Execute <var>consequent-commands</var> as long as
-<var>test-commands</var> has an exit status of zero.
+<p>Execute <var class="var">consequent-commands</var> as long as
+<var class="var">test-commands</var> has an exit status of zero.
The return status is the exit status of the last command executed
-in <var>consequent-commands</var>, or zero if none was executed.
+in <var class="var">consequent-commands</var>, or zero if none was executed.
</p>
</dd>
-<dt id='index-for'><span><code>for</code><a href='#index-for' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The syntax of the <code>for</code> command is:
+<dt><a id="index-for"></a><span><code class="code">for</code><a class="copiable-link" href="#index-for"> ¶</a></span></dt>
+<dd><p>The syntax of the <code class="code">for</code> command is:
</p>
<div class="example">
-<pre class="example">for <var>name</var> [ [in [<var>words</var> …] ] ; ] do <var>commands</var>; done
+<pre class="example-preformatted">for <var class="var">name</var> [ [in [<var class="var">words</var> ...] ] ; ] do <var class="var">commands</var>; done
</pre></div>
-<p>Expand <var>words</var> (see <a href="#Shell-Expansions">Shell Expansions</a>), and execute <var>commands</var>
+<p>Expand <var class="var">words</var> (see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>), and execute <var class="var">commands</var>
once for each member
-in the resultant list, with <var>name</var> bound to the current member.
-If ‘<samp>in <var>words</var></samp>’ is not present, the <code>for</code> command
-executes the <var>commands</var> once for each positional parameter that is
-set, as if ‘<samp>in "$@"</samp>’ had been specified
-(see <a href="#Special-Parameters">Special Parameters</a>).
+in the resultant list, with <var class="var">name</var> bound to the current member.
+If ‘<samp class="samp">in <var class="var">words</var></samp>’ is not present, the <code class="code">for</code> command
+executes the <var class="var">commands</var> once for each positional parameter that is
+set, as if ‘<samp class="samp">in "$@"</samp>’ had been specified
+(see <a class="pxref" href="#Special-Parameters">Special Parameters</a>).
</p>
<p>The return status is the exit status of the last command that executes.
-If there are no items in the expansion of <var>words</var>, no commands are
+If there are no items in the expansion of <var class="var">words</var>, no commands are
executed, and the return status is zero.
</p>
-<p>An alternate form of the <code>for</code> command is also supported:
+<p>An alternate form of the <code class="code">for</code> command is also supported:
</p>
<div class="example">
-<pre class="example">for (( <var>expr1</var> ; <var>expr2</var> ; <var>expr3</var> )) ; do <var>commands</var> ; done
+<pre class="example-preformatted">for (( <var class="var">expr1</var> ; <var class="var">expr2</var> ; <var class="var">expr3</var> )) ; do <var class="var">commands</var> ; done
</pre></div>
-<p>First, the arithmetic expression <var>expr1</var> is evaluated according
-to the rules described below (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>).
-The arithmetic expression <var>expr2</var> is then evaluated repeatedly
+<p>First, the arithmetic expression <var class="var">expr1</var> is evaluated according
+to the rules described below (see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>).
+The arithmetic expression <var class="var">expr2</var> is then evaluated repeatedly
until it evaluates to zero.
-Each time <var>expr2</var> evaluates to a non-zero value, <var>commands</var> are
-executed and the arithmetic expression <var>expr3</var> is evaluated.
+Each time <var class="var">expr2</var> evaluates to a non-zero value, <var class="var">commands</var> are
+executed and the arithmetic expression <var class="var">expr3</var> is evaluated.
If any expression is omitted, it behaves as if it evaluates to 1.
-The return value is the exit status of the last command in <var>commands</var>
+The return value is the exit status of the last command in <var class="var">commands</var>
that is executed, or false if any of the expressions is invalid.
</p></dd>
</dl>
-<p>The <code>break</code> and <code>continue</code> builtins (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
+<p>The <code class="code">break</code> and <code class="code">continue</code> builtins (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
may be used to control loop execution.
</p>
<hr>
</div>
-<div class="subsubsection" id="Conditional-Constructs">
-<div class="header">
+<div class="subsubsection-level-extent" id="Conditional-Constructs">
+<div class="nav-panel">
<p>
Next: <a href="#Command-Grouping" accesskey="n" rel="next">Grouping Commands</a>, Previous: <a href="#Looping-Constructs" accesskey="p" rel="prev">Looping Constructs</a>, Up: <a href="#Compound-Commands" accesskey="u" rel="up">Compound Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Conditional-Constructs-1"></span><h4 class="subsubsection">3.2.5.2 Conditional Constructs</h4>
-<span id="index-commands_002c-conditional"></span>
+<h4 class="subsubsection" id="Conditional-Constructs-1"><span>3.2.5.2 Conditional Constructs<a class="copiable-link" href="#Conditional-Constructs-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-commands_002c-conditional"></a>
-<dl compact="compact">
-<dt id='index-if'><span><code>if</code><a href='#index-if' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-then"></span>
-<span id="index-else"></span>
-<span id="index-elif"></span>
-<span id="index-fi"></span>
-<p>The syntax of the <code>if</code> command is:
+<dl class="table">
+<dt><a class="index-entry-id" id="index-then"></a>
+<a class="index-entry-id" id="index-else"></a>
+<a class="index-entry-id" id="index-elif"></a>
+<a class="index-entry-id" id="index-fi"></a>
+<a id="index-if"></a><span><code class="code">if</code><a class="copiable-link" href="#index-if"> ¶</a></span></dt>
+<dd><p>The syntax of the <code class="code">if</code> command is:
</p>
<div class="example">
-<pre class="example">if <var>test-commands</var>; then
- <var>consequent-commands</var>;
-[elif <var>more-test-commands</var>; then
- <var>more-consequents</var>;]
-[else <var>alternate-consequents</var>;]
+<pre class="example-preformatted">if <var class="var">test-commands</var>; then
+ <var class="var">consequent-commands</var>;
+[elif <var class="var">more-test-commands</var>; then
+ <var class="var">more-consequents</var>;]
+[else <var class="var">alternate-consequents</var>;]
fi
</pre></div>
-<p>The <var>test-commands</var> list is executed, and if its return status is zero,
-the <var>consequent-commands</var> list is executed.
-If <var>test-commands</var> returns a non-zero status, each <code>elif</code> list
+<p>The <var class="var">test-commands</var> list is executed, and if its return status is zero,
+the <var class="var">consequent-commands</var> list is executed.
+If <var class="var">test-commands</var> returns a non-zero status, each <code class="code">elif</code> list
is executed in turn, and if its exit status is zero,
-the corresponding <var>more-consequents</var> is executed and the
+the corresponding <var class="var">more-consequents</var> is executed and the
command completes.
-If ‘<samp>else <var>alternate-consequents</var></samp>’ is present, and
-the final command in the final <code>if</code> or <code>elif</code> clause
-has a non-zero exit status, then <var>alternate-consequents</var> is executed.
+If ‘<samp class="samp">else <var class="var">alternate-consequents</var></samp>’ is present, and
+the final command in the final <code class="code">if</code> or <code class="code">elif</code> clause
+has a non-zero exit status, then <var class="var">alternate-consequents</var> is executed.
The return status is the exit status of the last command executed, or
zero if no condition tested true.
</p>
</dd>
-<dt id='index-case'><span><code>case</code><a href='#index-case' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-in"></span>
-<span id="index-esac"></span>
-<p>The syntax of the <code>case</code> command is:
+<dt><a class="index-entry-id" id="index-in"></a>
+<a class="index-entry-id" id="index-esac"></a>
+<a id="index-case"></a><span><code class="code">case</code><a class="copiable-link" href="#index-case"> ¶</a></span></dt>
+<dd><p>The syntax of the <code class="code">case</code> command is:
</p>
<div class="example">
-<pre class="example">case <var>word</var> in
- [ [(] <var>pattern</var> [| <var>pattern</var>]…) <var>command-list</var> ;;]…
+<pre class="example-preformatted">case <var class="var">word</var> in
+ [ [(] <var class="var">pattern</var> [| <var class="var">pattern</var>]...) <var class="var">command-list</var> ;;]...
esac
</pre></div>
-<p><code>case</code> will selectively execute the <var>command-list</var> corresponding to
-the first <var>pattern</var> that matches <var>word</var>.
+<p><code class="code">case</code> will selectively execute the <var class="var">command-list</var> corresponding to
+the first <var class="var">pattern</var> that matches <var class="var">word</var>.
The match is performed according
-to the rules described below in <a href="#Pattern-Matching">Pattern Matching</a>.
-If the <code>nocasematch</code> shell option
-(see the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+to the rules described below in <a class="ref" href="#Pattern-Matching">Pattern Matching</a>.
+If the <code class="code">nocasematch</code> shell option
+(see the description of <code class="code">shopt</code> in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
is enabled, the match is performed without regard to the case
of alphabetic characters.
-The ‘<samp>|</samp>’ is used to separate multiple patterns, and the ‘<samp>)</samp>’
+The ‘<samp class="samp">|</samp>’ is used to separate multiple patterns, and the ‘<samp class="samp">)</samp>’
operator terminates a pattern list.
A list of patterns and an associated command-list is known
-as a <var>clause</var>.
+as a <var class="var">clause</var>.
</p>
-<p>Each clause must be terminated with ‘<samp>;;</samp>’, ‘<samp>;&</samp>’, or ‘<samp>;;&</samp>’.
-The <var>word</var> undergoes tilde expansion, parameter expansion, command
+<p>Each clause must be terminated with ‘<samp class="samp">;;</samp>’, ‘<samp class="samp">;&</samp>’, or ‘<samp class="samp">;;&</samp>’.
+The <var class="var">word</var> undergoes tilde expansion, parameter expansion, command
substitution, arithmetic expansion, and quote removal
-(see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>)
+(see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>)
before matching is attempted.
-Each <var>pattern</var> undergoes tilde expansion, parameter expansion,
+Each <var class="var">pattern</var> undergoes tilde expansion, parameter expansion,
command substitution, arithmetic expansion, process substitution, and
quote removal.
</p>
-<p>There may be an arbitrary number of <code>case</code> clauses, each terminated
-by a ‘<samp>;;</samp>’, ‘<samp>;&</samp>’, or ‘<samp>;;&</samp>’.
+<p>There may be an arbitrary number of <code class="code">case</code> clauses, each terminated
+by a ‘<samp class="samp">;;</samp>’, ‘<samp class="samp">;&</samp>’, or ‘<samp class="samp">;;&</samp>’.
The first pattern that matches determines the
command-list that is executed.
-It’s a common idiom to use ‘<samp>*</samp>’ as the final pattern to define the
+It’s a common idiom to use ‘<samp class="samp">*</samp>’ as the final pattern to define the
default case, since that pattern will always match.
</p>
-<p>Here is an example using <code>case</code> in a script that could be used to
+<p>Here is an example using <code class="code">case</code> in a script that could be used to
describe one interesting feature of an animal:
</p>
<div class="example">
-<pre class="example">echo -n "Enter the name of an animal: "
+<pre class="example-preformatted">echo -n "Enter the name of an animal: "
read ANIMAL
echo -n "The $ANIMAL has "
case $ANIMAL in
</pre></div>
-<p>If the ‘<samp>;;</samp>’ operator is used, no subsequent matches are attempted after
+<p>If the ‘<samp class="samp">;;</samp>’ operator is used, no subsequent matches are attempted after
the first pattern match.
-Using ‘<samp>;&</samp>’ in place of ‘<samp>;;</samp>’ causes execution to continue with
-the <var>command-list</var> associated with the next clause, if any.
-Using ‘<samp>;;&</samp>’ in place of ‘<samp>;;</samp>’ causes the shell to test the patterns
-in the next clause, if any, and execute any associated <var>command-list</var>
+Using ‘<samp class="samp">;&</samp>’ in place of ‘<samp class="samp">;;</samp>’ causes execution to continue with
+the <var class="var">command-list</var> associated with the next clause, if any.
+Using ‘<samp class="samp">;;&</samp>’ in place of ‘<samp class="samp">;;</samp>’ causes the shell to test the patterns
+in the next clause, if any, and execute any associated <var class="var">command-list</var>
on a successful match,
continuing the case statement execution as if the pattern list had not matched.
</p>
-<p>The return status is zero if no <var>pattern</var> is matched. Otherwise, the
-return status is the exit status of the <var>command-list</var> executed.
+<p>The return status is zero if no <var class="var">pattern</var> is matched. Otherwise, the
+return status is the exit status of the <var class="var">command-list</var> executed.
</p>
</dd>
-<dt id='index-select'><span><code>select</code><a href='#index-select' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-select"></a><span><code class="code">select</code><a class="copiable-link" href="#index-select"> ¶</a></span></dt>
<dd>
-<p>The <code>select</code> construct allows the easy generation of menus.
-It has almost the same syntax as the <code>for</code> command:
+<p>The <code class="code">select</code> construct allows the easy generation of menus.
+It has almost the same syntax as the <code class="code">for</code> command:
</p>
<div class="example">
-<pre class="example">select <var>name</var> [in <var>words</var> …]; do <var>commands</var>; done
+<pre class="example-preformatted">select <var class="var">name</var> [in <var class="var">words</var> ...]; do <var class="var">commands</var>; done
</pre></div>
-<p>The list of words following <code>in</code> is expanded, generating a list
+<p>The list of words following <code class="code">in</code> is expanded, generating a list
of items, and the set of expanded words is printed on the standard
error output stream, each preceded by a number. If the
-‘<samp>in <var>words</var></samp>’ is omitted, the positional parameters are printed,
-as if ‘<samp>in "$@"</samp>’ had been specified.
-<code>select</code> then displays the <code>PS3</code>
+‘<samp class="samp">in <var class="var">words</var></samp>’ is omitted, the positional parameters are printed,
+as if ‘<samp class="samp">in "$@"</samp>’ had been specified.
+<code class="code">select</code> then displays the <code class="env">PS3</code>
prompt and reads a line from the standard input.
If the line consists of a number corresponding to one of the displayed
-words, then the value of <var>name</var> is set to that word.
+words, then the value of <var class="var">name</var> is set to that word.
If the line is empty, the words and prompt are displayed again.
-If <code>EOF</code> is read, the <code>select</code> command completes and returns 1.
-Any other value read causes <var>name</var> to be set to null.
-The line read is saved in the variable <code>REPLY</code>.
+If <code class="code">EOF</code> is read, the <code class="code">select</code> command completes and returns 1.
+Any other value read causes <var class="var">name</var> to be set to null.
+The line read is saved in the variable <code class="env">REPLY</code>.
</p>
-<p>The <var>commands</var> are executed after each selection until a
-<code>break</code> command is executed, at which
-point the <code>select</code> command completes.
+<p>The <var class="var">commands</var> are executed after each selection until a
+<code class="code">break</code> command is executed, at which
+point the <code class="code">select</code> command completes.
</p>
<p>Here is an example that allows the user to pick a filename from the
current directory, and displays the name and index of the file
selected.
</p>
<div class="example">
-<pre class="example">select fname in *;
+<pre class="example-preformatted">select fname in *;
do
echo you picked $fname \($REPLY\)
break;
</pre></div>
</dd>
-<dt><span><code>((…))</code></span></dt>
+<dt><code class="code">((…))</code></dt>
<dd><div class="example">
-<pre class="example">(( <var>expression</var> ))
+<pre class="example-preformatted">(( <var class="var">expression</var> ))
</pre></div>
-<p>The arithmetic <var>expression</var> is evaluated according to the rules
-described below (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>).
-The <var>expression</var> undergoes the same expansions
+<p>The arithmetic <var class="var">expression</var> is evaluated according to the rules
+described below (see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>).
+The <var class="var">expression</var> undergoes the same expansions
as if it were within double quotes,
-but double quote characters in <var>expression</var> are not treated specially
+but double quote characters in <var class="var">expression</var> are not treated specially
are removed.
If the value of the expression is non-zero, the return status is 0;
otherwise the return status is 1.
</p>
</dd>
-<dt id='index-_005b_005b'><span><code>[[…]]</code><a href='#index-_005b_005b' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_005d_005d"></span>
-<div class="example">
-<pre class="example">[[ <var>expression</var> ]]
+<dt><a class="index-entry-id" id="index-_005d_005d"></a>
+<a id="index-_005b_005b"></a><span><code class="code">[[…]]</code><a class="copiable-link" href="#index-_005b_005b"> ¶</a></span></dt>
+<dd><div class="example">
+<pre class="example-preformatted">[[ <var class="var">expression</var> ]]
</pre></div>
<p>Return a status of 0 or 1 depending on the evaluation of
-the conditional expression <var>expression</var>.
+the conditional expression <var class="var">expression</var>.
Expressions are composed of the primaries described below in
-<a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>.
-The words between the <code>[[</code> and <code>]]</code> do not undergo word splitting
+<a class="ref" href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>.
+The words between the <code class="code">[[</code> and <code class="code">]]</code> do not undergo word splitting
and filename expansion.
The shell performs tilde expansion, parameter and
variable expansion, arithmetic expansion, command substitution, process
substitution, and quote removal on those words
(the expansions that would occur if the words were enclosed in double quotes).
-Conditional operators such as ‘<samp>-f</samp>’ must be unquoted to be recognized
+Conditional operators such as ‘<samp class="samp">-f</samp>’ must be unquoted to be recognized
as primaries.
</p>
-<p>When used with <code>[[</code>, the ‘<samp><</samp>’ and ‘<samp>></samp>’ operators sort
+<p>When used with <code class="code">[[</code>, the ‘<samp class="samp"><</samp>’ and ‘<samp class="samp">></samp>’ operators sort
lexicographically using the current locale.
</p>
-<p>When the ‘<samp>==</samp>’ and ‘<samp>!=</samp>’ operators are used, the string to the
+<p>When the ‘<samp class="samp">==</samp>’ and ‘<samp class="samp">!=</samp>’ operators are used, the string to the
right of the operator is considered a pattern and matched according
-to the rules described below in <a href="#Pattern-Matching">Pattern Matching</a>,
-as if the <code>extglob</code> shell option were enabled.
-The ‘<samp>=</samp>’ operator is identical to ‘<samp>==</samp>’.
-If the <code>nocasematch</code> shell option
-(see the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+to the rules described below in <a class="ref" href="#Pattern-Matching">Pattern Matching</a>,
+as if the <code class="code">extglob</code> shell option were enabled.
+The ‘<samp class="samp">=</samp>’ operator is identical to ‘<samp class="samp">==</samp>’.
+If the <code class="code">nocasematch</code> shell option
+(see the description of <code class="code">shopt</code> in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
is enabled, the match is performed without regard to the case
of alphabetic characters.
-The return value is 0 if the string matches (‘<samp>==</samp>’) or does not
-match (‘<samp>!=</samp>’) the pattern, and 1 otherwise.
+The return value is 0 if the string matches (‘<samp class="samp">==</samp>’) or does not
+match (‘<samp class="samp">!=</samp>’) the pattern, and 1 otherwise.
</p>
<p>If you quote any part of the pattern,
using any of the shell’s quoting mechanisms,
This means every character in the quoted portion matches itself,
instead of having any special pattern matching meaning.
</p>
-<p>An additional binary operator, ‘<samp>=~</samp>’, is available, with the same
-precedence as ‘<samp>==</samp>’ and ‘<samp>!=</samp>’.
-When you use ‘<samp>=~</samp>’, the string to the right of the operator is considered
-a <small>POSIX</small> extended regular expression pattern and matched accordingly
-(using the <small>POSIX</small> <code>regcomp</code> and <code>regexec</code> interfaces
-usually described in <i>regex</i>(3)).
+<p>An additional binary operator, ‘<samp class="samp">=~</samp>’, is available, with the same
+precedence as ‘<samp class="samp">==</samp>’ and ‘<samp class="samp">!=</samp>’.
+When you use ‘<samp class="samp">=~</samp>’, the string to the right of the operator is considered
+a <small class="sc">POSIX</small> extended regular expression pattern and matched accordingly
+(using the <small class="sc">POSIX</small> <code class="code">regcomp</code> and <code class="code">regexec</code> interfaces
+usually described in <i class="i">regex</i>(3)).
The return value is 0 if the string matches the pattern, and 1 if it does not.
If the regular expression is syntactically incorrect, the conditional
expression returns 2.
-If the <code>nocasematch</code> shell option
-(see the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+If the <code class="code">nocasematch</code> shell option
+(see the description of <code class="code">shopt</code> in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
is enabled, the match is performed without regard to the case
of alphabetic characters.
</p>
</p>
<p>The pattern will match if it matches any part of the string.
If you want to force the pattern to match the entire string,
-anchor the pattern using the ‘<samp>^</samp>’ and ‘<samp>$</samp>’ regular expression
+anchor the pattern using the ‘<samp class="samp">^</samp>’ and ‘<samp class="samp">$</samp>’ regular expression
operators.
</p>
<p>For example, the following will match a line
-(stored in the shell variable <code>line</code>)
+(stored in the shell variable <code class="code">line</code>)
if there is a sequence of characters anywhere in the value consisting of
any number, including zero, of
-characters in the <code>space</code> character class,
-immediately followed by zero or one instances of ‘<samp>a</samp>’,
-then a ‘<samp>b</samp>’:
+characters in the <code class="code">space</code> character class,
+immediately followed by zero or one instances of ‘<samp class="samp">a</samp>’,
+then a ‘<samp class="samp">b</samp>’:
</p>
<div class="example">
-<pre class="example">[[ $line =~ [[:space:]]*(a)?b ]]
+<pre class="example-preformatted">[[ $line =~ [[:space:]]*(a)?b ]]
</pre></div>
-<p>That means values for <code>line</code> like
-‘<samp>aab</samp>’, ‘<samp> aaaaaab</samp>’, ‘<samp>xaby</samp>’, and ‘<samp> ab</samp>’
+<p>That means values for <code class="code">line</code> like
+‘<samp class="samp">aab</samp>’, ‘<samp class="samp"> aaaaaab</samp>’, ‘<samp class="samp">xaby</samp>’, and ‘<samp class="samp"> ab</samp>’
will all match,
-as will a line containing a ‘<samp>b</samp>’ anywhere in its value.
+as will a line containing a ‘<samp class="samp">b</samp>’ anywhere in its value.
</p>
<p>If you want to match a character that’s special to the regular expression
-grammar (‘<samp>^$|[]()\.*+?</samp>’), it has to be quoted to remove its special
+grammar (‘<samp class="samp">^$|[]()\.*+?</samp>’), it has to be quoted to remove its special
meaning.
-This means that in the pattern ‘<samp>xxx.txt</samp>’, the ‘<samp>.</samp>’ matches any
+This means that in the pattern ‘<samp class="samp">xxx.txt</samp>’, the ‘<samp class="samp">.</samp>’ matches any
character in the string (its usual regular expression meaning), but in the
-pattern ‘<samp>"xxx.txt"</samp>’, it can only match a literal ‘<samp>.</samp>’.
+pattern ‘<samp class="samp">"xxx.txt"</samp>’, it can only match a literal ‘<samp class="samp">.</samp>’.
</p>
<p>Likewise, if you want to include a character in your pattern that has a
special meaning to the regular expression grammar, you must make sure it’s
not quoted.
If you want to anchor a pattern at the beginning or end of the string,
-for instance, you cannot quote the ‘<samp>^</samp>’ or ‘<samp>$</samp>’
+for instance, you cannot quote the ‘<samp class="samp">^</samp>’ or ‘<samp class="samp">$</samp>’
characters using any form of shell quoting.
</p>
-<p>If you want to match ‘<samp>initial string</samp>’ at the start of a line,
+<p>If you want to match ‘<samp class="samp">initial string</samp>’ at the start of a line,
the following will work:
</p><div class="example">
-<pre class="example">[[ $line =~ ^"initial string" ]]
+<pre class="example-preformatted">[[ $line =~ ^"initial string" ]]
</pre></div>
<p>but this will not:
</p><div class="example">
-<pre class="example">[[ $line =~ "^initial string" ]]
+<pre class="example-preformatted">[[ $line =~ "^initial string" ]]
</pre></div>
-<p>because in the second example the ‘<samp>^</samp>’ is quoted and doesn’t have its
+<p>because in the second example the ‘<samp class="samp">^</samp>’ is quoted and doesn’t have its
usual special meaning.
</p>
<p>It is sometimes difficult to specify a regular expression properly
For example, the following is equivalent to the pattern used above:
</p>
<div class="example">
-<pre class="example">pattern='[[:space:]]*(a)?b'
+<pre class="example-preformatted">pattern='[[:space:]]*(a)?b'
[[ $line =~ $pattern ]]
</pre></div>
backslashes are used by both the shell and regular expressions to remove
the special meaning from the following character.
This means that after the shell’s word expansions complete
-(see <a href="#Shell-Expansions">Shell Expansions</a>),
+(see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>),
any backslashes remaining in parts of the pattern
that were originally not quoted can remove the
special meaning of pattern characters.
the regular expression treats those remaining backslashes as literal,
if they appeared in a quoted portion.
</p>
-<p>The following two sets of commands are <em>not</em> equivalent:
+<p>The following two sets of commands are <em class="emph">not</em> equivalent:
</p>
<div class="example">
-<pre class="example">pattern='\.'
+<pre class="example-preformatted">pattern='\.'
[[ . =~ $pattern ]]
[[ . =~ \. ]]
<p>The first two matches will succeed, but the second two will not, because
in the second two the backslash will be part of the pattern to be matched.
In the first two examples, the pattern passed to the regular expression
-parser is ‘<samp>\.</samp>’. The backslash removes the special meaning from
-‘<samp>.</samp>’, so the literal ‘<samp>.</samp>’ matches.
+parser is ‘<samp class="samp">\.</samp>’. The backslash removes the special meaning from
+‘<samp class="samp">.</samp>’, so the literal ‘<samp class="samp">.</samp>’ matches.
In the second two examples, the pattern passed to the regular expression
-parser has the backslash quoted (e.g., ‘<samp>\\\.</samp>’), which will not match
+parser has the backslash quoted (e.g., ‘<samp class="samp">\\\.</samp>’), which will not match
the string, since it does not contain a backslash.
-If the string in the first examples were anything other than ‘<samp>.</samp>’, say
-‘<samp>a</samp>’, the pattern would not match, because the quoted ‘<samp>.</samp>’ in the
+If the string in the first examples were anything other than ‘<samp class="samp">.</samp>’, say
+‘<samp class="samp">a</samp>’, the pattern would not match, because the quoted ‘<samp class="samp">.</samp>’ in the
pattern loses its special meaning of matching any single character.
</p>
<p>Bracket expressions in regular expressions can be sources of errors as well,
without quoting them, so they are sometimes useful for this purpose.
</p>
<p>Though it might seem like a strange way to write it, the following pattern
-will match a ‘<samp>.</samp>’ in the string:
+will match a ‘<samp class="samp">.</samp>’ in the string:
</p>
<div class="example">
-<pre class="example">[[ . =~ [.] ]]
+<pre class="example-preformatted">[[ . =~ [.] ]]
</pre></div>
<p>The shell performs any word expansions before passing the pattern
as much as possible, so shell quoting should be sufficient to quote
special pattern characters where that’s necessary.
</p>
-<p>The array variable <code>BASH_REMATCH</code> records which parts of the string
+<p>The array variable <code class="code">BASH_REMATCH</code> records which parts of the string
matched the pattern.
-The element of <code>BASH_REMATCH</code> with index 0 contains the portion of
+The element of <code class="code">BASH_REMATCH</code> with index 0 contains the portion of
the string matching the entire regular expression.
Substrings matched by parenthesized subexpressions within the regular
-expression are saved in the remaining <code>BASH_REMATCH</code> indices.
-The element of <code>BASH_REMATCH</code> with index <var>n</var> is the portion of the
-string matching the <var>n</var>th parenthesized subexpression.
+expression are saved in the remaining <code class="code">BASH_REMATCH</code> indices.
+The element of <code class="code">BASH_REMATCH</code> with index <var class="var">n</var> is the portion of the
+string matching the <var class="var">n</var>th parenthesized subexpression.
</p>
<p>Bash sets
-<code>BASH_REMATCH</code>
+<code class="code">BASH_REMATCH</code>
in the global scope; declaring it as a local variable will lead to
unexpected results.
</p>
<p>Expressions may be combined using the following operators, listed
in decreasing order of precedence:
</p>
-<dl compact="compact">
-<dt><span><code>( <var>expression</var> )</code></span></dt>
-<dd><p>Returns the value of <var>expression</var>.
+<dl class="table">
+<dt><code class="code">( <var class="var">expression</var> )</code></dt>
+<dd><p>Returns the value of <var class="var">expression</var>.
This may be used to override the normal precedence of operators.
</p>
</dd>
-<dt><span><code>! <var>expression</var></code></span></dt>
-<dd><p>True if <var>expression</var> is false.
+<dt><code class="code">! <var class="var">expression</var></code></dt>
+<dd><p>True if <var class="var">expression</var> is false.
</p>
</dd>
-<dt><span><code><var>expression1</var> && <var>expression2</var></code></span></dt>
-<dd><p>True if both <var>expression1</var> and <var>expression2</var> are true.
+<dt><code class="code"><var class="var">expression1</var> && <var class="var">expression2</var></code></dt>
+<dd><p>True if both <var class="var">expression1</var> and <var class="var">expression2</var> are true.
</p>
</dd>
-<dt><span><code><var>expression1</var> || <var>expression2</var></code></span></dt>
-<dd><p>True if either <var>expression1</var> or <var>expression2</var> is true.
+<dt><code class="code"><var class="var">expression1</var> || <var class="var">expression2</var></code></dt>
+<dd><p>True if either <var class="var">expression1</var> or <var class="var">expression2</var> is true.
</p></dd>
</dl>
-<p>The <code>&&</code> and <code>||</code> operators do not evaluate <var>expression2</var> if the
-value of <var>expression1</var> is sufficient to determine the return
+<p>The <code class="code">&&</code> and <code class="code">||</code> operators do not evaluate <var class="var">expression2</var> if the
+value of <var class="var">expression1</var> is sufficient to determine the return
value of the entire conditional expression.
</p></dd>
</dl>
<hr>
</div>
-<div class="subsubsection" id="Command-Grouping">
-<div class="header">
+<div class="subsubsection-level-extent" id="Command-Grouping">
+<div class="nav-panel">
<p>
Previous: <a href="#Conditional-Constructs" accesskey="p" rel="prev">Conditional Constructs</a>, Up: <a href="#Compound-Commands" accesskey="u" rel="up">Compound Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Grouping-Commands"></span><h4 class="subsubsection">3.2.5.3 Grouping Commands</h4>
-<span id="index-commands_002c-grouping"></span>
+<h4 class="subsubsection" id="Grouping-Commands"><span>3.2.5.3 Grouping Commands<a class="copiable-link" href="#Grouping-Commands"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-commands_002c-grouping"></a>
<p>Bash provides two ways to group a list of commands to be executed
as a unit. When commands are grouped, redirections may be applied
to the entire command list. For example, the output of all the
commands in the list may be redirected to a single stream.
</p>
-<dl compact="compact">
-<dt><span><code>()</code></span></dt>
+<dl class="table">
+<dt><code class="code">()</code></dt>
<dd><div class="example">
-<pre class="example">( <var>list</var> )
+<pre class="example-preformatted">( <var class="var">list</var> )
</pre></div>
<p>Placing a list of commands between parentheses forces the shell to create
-a subshell (see <a href="#Command-Execution-Environment">Command Execution Environment</a>), and each
-of the commands in <var>list</var> is executed in that subshell environment.
-Since the <var>list</var> is executed in a subshell, variable assignments do not
+a subshell (see <a class="pxref" href="#Command-Execution-Environment">Command Execution Environment</a>), and each
+of the commands in <var class="var">list</var> is executed in that subshell environment.
+Since the <var class="var">list</var> is executed in a subshell, variable assignments do not
remain in effect after the subshell completes.
</p>
</dd>
-<dt id='index-_007b'><span><code>{}</code><a href='#index-_007b' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_007d"></span>
-<div class="example">
-<pre class="example">{ <var>list</var>; }
+<dt><a class="index-entry-id" id="index-_007d"></a>
+<a id="index-_007b"></a><span><code class="code">{}</code><a class="copiable-link" href="#index-_007b"> ¶</a></span></dt>
+<dd><div class="example">
+<pre class="example-preformatted">{ <var class="var">list</var>; }
</pre></div>
<p>Placing a list of commands between curly braces causes the list to
be executed in the current shell context. No subshell is created.
-The semicolon (or newline) following <var>list</var> is required.
+The semicolon (or newline) following <var class="var">list</var> is required.
</p></dd>
</dl>
<p>In addition to the creation of a subshell, there is a subtle difference
between these two constructs due to historical reasons. The braces
-are reserved words, so they must be separated from the <var>list</var>
-by <code>blank</code>s or other shell metacharacters.
+are reserved words, so they must be separated from the <var class="var">list</var>
+by <code class="code">blank</code>s or other shell metacharacters.
The parentheses are operators, and are
recognized as separate tokens by the shell even if they are not separated
-from the <var>list</var> by whitespace.
+from the <var class="var">list</var> by whitespace.
</p>
<p>The exit status of both of these constructs is the exit status of
-<var>list</var>.
+<var class="var">list</var>.
</p>
<hr>
</div>
</div>
-<div class="subsection" id="Coprocesses">
-<div class="header">
+<div class="subsection-level-extent" id="Coprocesses">
+<div class="nav-panel">
<p>
Next: <a href="#GNU-Parallel" accesskey="n" rel="next">GNU Parallel</a>, Previous: <a href="#Compound-Commands" accesskey="p" rel="prev">Compound Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Coprocesses-1"></span><h4 class="subsection">3.2.6 Coprocesses</h4>
-<span id="index-coprocess"></span>
+<h4 class="subsection" id="Coprocesses-1"><span>3.2.6 Coprocesses<a class="copiable-link" href="#Coprocesses-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-coprocess"></a>
-<p>A <code>coprocess</code> is a shell command preceded by the <code>coproc</code>
+<p>A <code class="code">coprocess</code> is a shell command preceded by the <code class="code">coproc</code>
reserved word.
A coprocess is executed asynchronously in a subshell, as if the command
-had been terminated with the ‘<samp>&</samp>’ control operator, with a two-way pipe
+had been terminated with the ‘<samp class="samp">&</samp>’ control operator, with a two-way pipe
established between the executing shell and the coprocess.
</p>
<p>The syntax for a coprocess is:
</p>
<div class="example">
-<pre class="example">coproc [<var>NAME</var>] <var>command</var> [<var>redirections</var>]
+<pre class="example-preformatted">coproc [<var class="var">NAME</var>] <var class="var">command</var> [<var class="var">redirections</var>]
</pre></div>
-<p>This creates a coprocess named <var>NAME</var>.
-<var>command</var> may be either a simple command (see <a href="#Simple-Commands">Simple Commands</a>)
-or a compound command (see <a href="#Compound-Commands">Compound Commands</a>).
-<var>NAME</var> is a shell variable name.
-If <var>NAME</var> is not supplied, the default name is <code>COPROC</code>.
+<p>This creates a coprocess named <var class="var">NAME</var>.
+<var class="var">command</var> may be either a simple command (see <a class="pxref" href="#Simple-Commands">Simple Commands</a>)
+or a compound command (see <a class="pxref" href="#Compound-Commands">Compound Commands</a>).
+<var class="var">NAME</var> is a shell variable name.
+If <var class="var">NAME</var> is not supplied, the default name is <code class="code">COPROC</code>.
</p>
<p>The recommended form to use for a coprocess is
</p>
<div class="example">
-<pre class="example">coproc <var>NAME</var> { <var>command</var>; }
+<pre class="example-preformatted">coproc <var class="var">NAME</var> { <var class="var">command</var>; }
</pre></div>
<p>This form is recommended because simple commands result in the coprocess
-always being named <code>COPROC</code>, and it is simpler to use and more complete
+always being named <code class="code">COPROC</code>, and it is simpler to use and more complete
than the other compound commands.
</p>
<p>There are other forms of coprocesses:
</p>
<div class="example">
-<pre class="example">coproc <var>NAME</var> <var>compound-command</var>
-coproc <var>compound-command</var>
-coproc <var>simple-command</var>
+<pre class="example-preformatted">coproc <var class="var">NAME</var> <var class="var">compound-command</var>
+coproc <var class="var">compound-command</var>
+coproc <var class="var">simple-command</var>
</pre></div>
-<p>If <var>command</var> is a compound command, <var>NAME</var> is optional. The
-word following <code>coproc</code> determines whether that word is interpreted
-as a variable name: it is interpreted as <var>NAME</var> if it is not a
+<p>If <var class="var">command</var> is a compound command, <var class="var">NAME</var> is optional. The
+word following <code class="code">coproc</code> determines whether that word is interpreted
+as a variable name: it is interpreted as <var class="var">NAME</var> if it is not a
reserved word that introduces a compound command.
-If <var>command</var> is a simple command, <var>NAME</var> is not allowed; this
-is to avoid confusion between <var>NAME</var> and the first word of the simple
+If <var class="var">command</var> is a simple command, <var class="var">NAME</var> is not allowed; this
+is to avoid confusion between <var class="var">NAME</var> and the first word of the simple
command.
</p>
<p>When the coprocess is executed, the shell creates an array variable
-(see <a href="#Arrays">Arrays</a>)
-named <var>NAME</var> in the context of the executing shell.
-The standard output of <var>command</var>
+(see <a class="pxref" href="#Arrays">Arrays</a>)
+named <var class="var">NAME</var> in the context of the executing shell.
+The standard output of <var class="var">command</var>
is connected via a pipe to a file descriptor in the executing shell,
-and that file descriptor is assigned to <var>NAME</var>[0].
-The standard input of <var>command</var>
+and that file descriptor is assigned to <var class="var">NAME</var>[0].
+The standard input of <var class="var">command</var>
is connected via a pipe to a file descriptor in the executing shell,
-and that file descriptor is assigned to <var>NAME</var>[1].
+and that file descriptor is assigned to <var class="var">NAME</var>[1].
This pipe is established before any redirections specified by the
-command (see <a href="#Redirections">Redirections</a>).
+command (see <a class="pxref" href="#Redirections">Redirections</a>).
The file descriptors can be utilized as arguments to shell commands
and redirections using standard word expansions.
Other than those created to execute command and process substitutions,
the file descriptors are not available in subshells.
</p>
<p>The process ID of the shell spawned to execute the coprocess is
-available as the value of the variable <code><var>NAME</var>_PID</code>.
-The <code>wait</code>
+available as the value of the variable <code class="env"><var class="var">NAME</var>_PID</code>.
+The <code class="code">wait</code>
builtin command may be used to wait for the coprocess to terminate.
</p>
<p>Since the coprocess is created as an asynchronous command,
-the <code>coproc</code> command always returns success.
-The return status of a coprocess is the exit status of <var>command</var>.
+the <code class="code">coproc</code> command always returns success.
+The return status of a coprocess is the exit status of <var class="var">command</var>.
</p>
<hr>
</div>
-<div class="subsection" id="GNU-Parallel">
-<div class="header">
+<div class="subsection-level-extent" id="GNU-Parallel">
+<div class="nav-panel">
<p>
Previous: <a href="#Coprocesses" accesskey="p" rel="prev">Coprocesses</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="GNU-Parallel-1"></span><h4 class="subsection">3.2.7 GNU Parallel</h4>
+<h4 class="subsection" id="GNU-Parallel-1"><span>3.2.7 GNU Parallel<a class="copiable-link" href="#GNU-Parallel-1"> ¶</a></span></h4>
<p>There are ways to run commands in parallel that are not built into Bash.
GNU Parallel is a tool to do just that.
they are filenames, usernames, hostnames, or lines read from files. GNU
Parallel provides shorthand references to many of the most common operations
(input lines, various portions of the input line, different ways to specify
-the input source, and so on). Parallel can replace <code>xargs</code> or feed
+the input source, and so on). Parallel can replace <code class="code">xargs</code> or feed
commands from its input sources to several different instances of Bash.
</p>
<p>For a complete description, refer to the GNU Parallel documentation, which
is available at
-<a href="https://www.gnu.org/software/parallel/parallel_tutorial.html">https://www.gnu.org/software/parallel/parallel_tutorial.html</a>.
+<a class="url" href="https://www.gnu.org/software/parallel/parallel_tutorial.html">https://www.gnu.org/software/parallel/parallel_tutorial.html</a>.
</p>
<hr>
</div>
</div>
-<div class="section" id="Shell-Functions">
-<div class="header">
+<div class="section-level-extent" id="Shell-Functions">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Parameters" accesskey="n" rel="next">Shell Parameters</a>, Previous: <a href="#Shell-Commands" accesskey="p" rel="prev">Shell Commands</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Functions-1"></span><h3 class="section">3.3 Shell Functions</h3>
-<span id="index-shell-function"></span>
-<span id="index-functions_002c-shell"></span>
+<h3 class="section" id="Shell-Functions-1"><span>3.3 Shell Functions<a class="copiable-link" href="#Shell-Functions-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-shell-function"></a>
+<a class="index-entry-id" id="index-functions_002c-shell"></a>
<p>Shell functions are a way to group commands for later execution
using a single name for the group. They are executed just like
shell context; no new process is created to interpret them.
</p>
<p>Functions are declared using this syntax:
-<span id="index-function"></span>
+<a class="index-entry-id" id="index-function"></a>
</p><div class="example">
-<pre class="example"><var>fname</var> () <var>compound-command</var> [ <var>redirections</var> ]
+<pre class="example-preformatted"><var class="var">fname</var> () <var class="var">compound-command</var> [ <var class="var">redirections</var> ]
</pre></div>
<p>or
</p>
<div class="example">
-<pre class="example">function <var>fname</var> [()] <var>compound-command</var> [ <var>redirections</var> ]
+<pre class="example-preformatted">function <var class="var">fname</var> [()] <var class="var">compound-command</var> [ <var class="var">redirections</var> ]
</pre></div>
-<p>This defines a shell function named <var>fname</var>. The reserved
-word <code>function</code> is optional.
-If the <code>function</code> reserved
+<p>This defines a shell function named <var class="var">fname</var>. The reserved
+word <code class="code">function</code> is optional.
+If the <code class="code">function</code> reserved
word is supplied, the parentheses are optional.
-The <em>body</em> of the function is the compound command
-<var>compound-command</var> (see <a href="#Compound-Commands">Compound Commands</a>).
-That command is usually a <var>list</var> enclosed between { and }, but
+The <em class="dfn">body</em> of the function is the compound command
+<var class="var">compound-command</var> (see <a class="pxref" href="#Compound-Commands">Compound Commands</a>).
+That command is usually a <var class="var">list</var> enclosed between { and }, but
may be any compound command listed above.
-If the <code>function</code> reserved word is used, but the
+If the <code class="code">function</code> reserved word is used, but the
parentheses are not supplied, the braces are recommended.
-<var>compound-command</var> is executed whenever <var>fname</var> is specified as the
+<var class="var">compound-command</var> is executed whenever <var class="var">fname</var> is specified as the
name of a simple command.
-When the shell is in <small>POSIX</small> mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>),
-<var>fname</var> must be a valid shell name and
+When the shell is in <small class="sc">POSIX</small> mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>),
+<var class="var">fname</var> must be a valid shell name and
may not be the same as one of the special builtins
-(see <a href="#Special-Builtins">Special Builtins</a>).
+(see <a class="pxref" href="#Special-Builtins">Special Builtins</a>).
In default mode, a function name can be any unquoted shell word that does
-not contain ‘<samp>$</samp>’.
-Any redirections (see <a href="#Redirections">Redirections</a>) associated with the shell function
+not contain ‘<samp class="samp">$</samp>’.
+Any redirections (see <a class="pxref" href="#Redirections">Redirections</a>) associated with the shell function
are performed when the function is executed.
-A function definition may be deleted using the <samp>-f</samp> option to the
-<code>unset</code> builtin (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+A function definition may be deleted using the <samp class="option">-f</samp> option to the
+<code class="code">unset</code> builtin (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
</p>
<p>The exit status of a function definition is zero unless a syntax error
occurs or a readonly function with the same name already exists.
</p>
<p>Note that for historical reasons, in the most common usage the curly braces
that surround the body of the function must be separated from the body by
-<code>blank</code>s or newlines.
+<code class="code">blank</code>s or newlines.
This is because the braces are reserved words and are only recognized
as such when they are separated from the command list
by whitespace or another shell metacharacter.
-Also, when using the braces, the <var>list</var> must be terminated by a semicolon,
-a ‘<samp>&</samp>’, or a newline.
+Also, when using the braces, the <var class="var">list</var> must be terminated by a semicolon,
+a ‘<samp class="samp">&</samp>’, or a newline.
</p>
<p>When a function is executed, the arguments to the
function become the positional parameters
-during its execution (see <a href="#Positional-Parameters">Positional Parameters</a>).
-The special parameter ‘<samp>#</samp>’ that expands to the number of
+during its execution (see <a class="pxref" href="#Positional-Parameters">Positional Parameters</a>).
+The special parameter ‘<samp class="samp">#</samp>’ that expands to the number of
positional parameters is updated to reflect the change.
-Special parameter <code>0</code> is unchanged.
-The first element of the <code>FUNCNAME</code> variable is set to the
+Special parameter <code class="code">0</code> is unchanged.
+The first element of the <code class="env">FUNCNAME</code> variable is set to the
name of the function while the function is executing.
</p>
<p>All other aspects of the shell execution
environment are identical between a function and its caller
with these exceptions:
-the <code>DEBUG</code> and <code>RETURN</code> traps
+the <code class="env">DEBUG</code> and <code class="env">RETURN</code> traps
are not inherited unless the function has been given the
-<code>trace</code> attribute using the <code>declare</code> builtin or
-the <code>-o functrace</code> option has been enabled with
-the <code>set</code> builtin,
-(in which case all functions inherit the <code>DEBUG</code> and <code>RETURN</code> traps),
-and the <code>ERR</code> trap is not inherited unless the <code>-o errtrace</code>
+<code class="code">trace</code> attribute using the <code class="code">declare</code> builtin or
+the <code class="code">-o functrace</code> option has been enabled with
+the <code class="code">set</code> builtin,
+(in which case all functions inherit the <code class="env">DEBUG</code> and <code class="env">RETURN</code> traps),
+and the <code class="env">ERR</code> trap is not inherited unless the <code class="code">-o errtrace</code>
shell option has been enabled.
-See <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>, for the description of the
-<code>trap</code> builtin.
+See <a class="xref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>, for the description of the
+<code class="code">trap</code> builtin.
</p>
-<p>The <code>FUNCNEST</code> variable, if set to a numeric value greater
+<p>The <code class="env">FUNCNEST</code> variable, if set to a numeric value greater
than 0, defines a maximum function nesting level. Function
invocations that exceed the limit cause the entire command to
abort.
</p>
-<p>If the builtin command <code>return</code>
+<p>If the builtin command <code class="code">return</code>
is executed in a function, the function completes and
execution resumes with the next command after the function
call.
-Any command associated with the <code>RETURN</code> trap is executed
+Any command associated with the <code class="code">RETURN</code> trap is executed
before execution resumes.
When a function completes, the values of the
-positional parameters and the special parameter ‘<samp>#</samp>’
+positional parameters and the special parameter ‘<samp class="samp">#</samp>’
are restored to the values they had prior to the function’s
-execution. If a numeric argument is given to <code>return</code>,
+execution. If a numeric argument is given to <code class="code">return</code>,
that is the function’s return status; otherwise the function’s
return status is the exit status of the last command executed
-before the <code>return</code>.
+before the <code class="code">return</code>.
</p>
<p>Variables local to the function may be declared with the
-<code>local</code> builtin (<em>local variables</em>).
+<code class="code">local</code> builtin (<em class="dfn">local variables</em>).
Ordinarily, variables and their values
are shared between a function and its caller.
These variables are visible only to
the function and the commands it invokes. This is particularly
important when a shell function calls other functions.
</p>
-<p>In the following description, the <em>current scope</em> is a currently-
+<p>In the following description, the <em class="dfn">current scope</em> is a currently-
executing function.
Previous scopes consist of that function’s caller and so on,
back to the "global" scope, where the shell is not executing
any shell function.
Consequently, a local variable at the current local scope is a variable
-declared using the <code>local</code> or <code>declare</code> builtins in the
+declared using the <code class="code">local</code> or <code class="code">declare</code> builtins in the
function that is currently executing.
</p>
<p>Local variables "shadow" variables with the same name declared at
refer to the local variable, leaving the global variable unmodified.
When the function returns, the global variable is once again visible.
</p>
-<p>The shell uses <em>dynamic scoping</em> to control a variable’s visibility
+<p>The shell uses <em class="dfn">dynamic scoping</em> to control a variable’s visibility
within functions.
With dynamic scoping, visible variables and their values
are a result of the sequence of function calls that caused execution
to reach the current function.
The value of a variable that a function sees depends
on its value within its caller, if any, whether that caller is
-the "global" scope or another shell function.
+the global scope or another shell function.
This is also the value that a local variable
-declaration "shadows", and the value that is restored when the function
+declaration shadows, and the value that is restored when the function
returns.
</p>
-<p>For example, if a variable <code>var</code> is declared as local in function
-<code>func1</code>, and <code>func1</code> calls another function <code>func2</code>,
-references to <code>var</code> made from within <code>func2</code> will resolve to the
-local variable <code>var</code> from <code>func1</code>, shadowing any global variable
-named <code>var</code>.
+<p>For example, if a variable <code class="env">var</code> is declared as local in function
+<code class="code">func1</code>, and <code class="code">func1</code> calls another function <code class="code">func2</code>,
+references to <code class="env">var</code> made from within <code class="code">func2</code> will resolve to the
+local variable <code class="env">var</code> from <code class="code">func1</code>, shadowing any global variable
+named <code class="env">var</code>.
</p>
<p>The following script demonstrates this behavior.
When executed, the script displays
</p>
<div class="example">
-<pre class="example">In func2, var = func1 local
+<pre class="example-preformatted">In func2, var = func1 local
</pre></div>
<div class="example">
-<pre class="example">func1()
+<pre class="example-preformatted">func1()
{
local var='func1 local'
func2
func1
</pre></div>
-<p>The <code>unset</code> builtin also acts using the same dynamic scope: if a
-variable is local to the current scope, <code>unset</code> will unset it;
+<p>The <code class="code">unset</code> builtin also acts using the same dynamic scope: if a
+variable is local to the current scope, <code class="code">unset</code> will unset it;
otherwise the unset will refer to the variable found in any calling scope
as described above.
If a variable at the current local scope is unset, it will remain so
scope will become visible.
If the unset acts on a variable at a previous scope, any instance of a
variable with that name that had been shadowed will become visible
-(see below how <code>localvar_unset</code>shell option changes this behavior).
+(see below how <code class="code">localvar_unset</code>shell option changes this behavior).
</p>
<p>Function names and definitions may be listed with the
-<samp>-f</samp> option to the <code>declare</code> (<code>typeset</code>)
-builtin command (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
-The <samp>-F</samp> option to <code>declare</code> or <code>typeset</code>
+<samp class="option">-f</samp> option to the <code class="code">declare</code> (<code class="code">typeset</code>)
+builtin command (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
+The <samp class="option">-F</samp> option to <code class="code">declare</code> or <code class="code">typeset</code>
will list the function names only
-(and optionally the source file and line number, if the <code>extdebug</code>
+(and optionally the source file and line number, if the <code class="code">extdebug</code>
shell option is enabled).
Functions may be exported so that child shell processes
(those created when executing a separate shell invocation)
automatically have them defined with the
-<samp>-f</samp> option to the <code>export</code> builtin
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+<samp class="option">-f</samp> option to the <code class="code">export</code> builtin
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
</p>
<p>Functions may be recursive.
-The <code>FUNCNEST</code> variable may be used to limit the depth of the
+The <code class="code">FUNCNEST</code> variable may be used to limit the depth of the
function call stack and restrict the number of function invocations.
By default, no limit is placed on the number of recursive calls.
</p>
<hr>
</div>
-<div class="section" id="Shell-Parameters">
-<div class="header">
+<div class="section-level-extent" id="Shell-Parameters">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Expansions" accesskey="n" rel="next">Shell Expansions</a>, Previous: <a href="#Shell-Functions" accesskey="p" rel="prev">Shell Functions</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Parameters-1"></span><h3 class="section">3.4 Shell Parameters</h3>
-<span id="index-parameters"></span>
-<span id="index-variable_002c-shell"></span>
-<span id="index-shell-variable"></span>
+<h3 class="section" id="Shell-Parameters-1"><span>3.4 Shell Parameters<a class="copiable-link" href="#Shell-Parameters-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-parameters"></a>
+<a class="index-entry-id" id="index-variable_002c-shell"></a>
+<a class="index-entry-id" id="index-shell-variable"></a>
-<p>A <em>parameter</em> is an entity that stores values.
-It can be a <code>name</code>, a number, or one of the special characters
+<p>A <em class="dfn">parameter</em> is an entity that stores values.
+It can be a <code class="code">name</code>, a number, or one of the special characters
listed below.
-A <em>variable</em> is a parameter denoted by a <code>name</code>.
-A variable has a <code>value</code> and zero or more <code>attributes</code>.
-Attributes are assigned using the <code>declare</code> builtin command
-(see the description of the <code>declare</code> builtin in <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+A <em class="dfn">variable</em> is a parameter denoted by a <code class="code">name</code>.
+A variable has a <code class="code">value</code> and zero or more <code class="code">attributes</code>.
+Attributes are assigned using the <code class="code">declare</code> builtin command
+(see the description of the <code class="code">declare</code> builtin in <a class="ref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p>
<p>A parameter is set if it has been assigned a value. The null string is
a valid value. Once a variable is set, it may be unset only by using
-the <code>unset</code> builtin command.
+the <code class="code">unset</code> builtin command.
</p>
<p>A variable may be assigned to by a statement of the form
</p><div class="example">
-<pre class="example"><var>name</var>=[<var>value</var>]
+<pre class="example-preformatted"><var class="var">name</var>=[<var class="var">value</var>]
</pre></div>
-<p>If <var>value</var>
+<p>If <var class="var">value</var>
is not given, the variable is assigned the null string. All
-<var>value</var>s undergo tilde expansion, parameter and variable expansion,
+<var class="var">value</var>s undergo tilde expansion, parameter and variable expansion,
command substitution, arithmetic expansion, and quote
-removal (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-If the variable has its <code>integer</code>
-attribute set, then <var>value</var>
-is evaluated as an arithmetic expression even if the <code>$((…))</code>
-expansion is not used (see <a href="#Arithmetic-Expansion">Arithmetic Expansion</a>).
+removal (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+If the variable has its <code class="code">integer</code>
+attribute set, then <var class="var">value</var>
+is evaluated as an arithmetic expression even if the <code class="code">$((…))</code>
+expansion is not used (see <a class="pxref" href="#Arithmetic-Expansion">Arithmetic Expansion</a>).
Word splitting and filename expansion are not performed.
Assignment statements may also appear as arguments to the
-<code>alias</code>,
-<code>declare</code>, <code>typeset</code>, <code>export</code>, <code>readonly</code>,
-and <code>local</code> builtin commands (<em>declaration</em> commands).
-When in <small>POSIX</small> mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>), these builtins may appear
-in a command after one or more instances of the <code>command</code> builtin
+<code class="code">alias</code>,
+<code class="code">declare</code>, <code class="code">typeset</code>, <code class="code">export</code>, <code class="code">readonly</code>,
+and <code class="code">local</code> builtin commands (<em class="dfn">declaration</em> commands).
+When in <small class="sc">POSIX</small> mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>), these builtins may appear
+in a command after one or more instances of the <code class="code">command</code> builtin
and retain these assignment statement properties.
</p>
<p>In the context where an assignment statement is assigning a value
-to a shell variable or array index (see <a href="#Arrays">Arrays</a>), the ‘<samp>+=</samp>’
+to a shell variable or array index (see <a class="pxref" href="#Arrays">Arrays</a>), the ‘<samp class="samp">+=</samp>’
operator can be used to
append to or add to the variable’s previous value.
-This includes arguments to builtin commands such as <code>declare</code> that
+This includes arguments to builtin commands such as <code class="code">declare</code> that
accept assignment statements (declaration commands).
-When ‘<samp>+=</samp>’ is applied to a variable for which the <code>integer</code> attribute
-has been set, <var>value</var> is evaluated as an arithmetic expression and
+When ‘<samp class="samp">+=</samp>’ is applied to a variable for which the <code class="code">integer</code> attribute
+has been set, <var class="var">value</var> is evaluated as an arithmetic expression and
added to the variable’s current value, which is also evaluated.
-When ‘<samp>+=</samp>’ is applied to an array variable using compound assignment
-(see <a href="#Arrays">Arrays</a>), the
-variable’s value is not unset (as it is when using ‘<samp>=</samp>’), and new
+When ‘<samp class="samp">+=</samp>’ is applied to an array variable using compound assignment
+(see <a class="pxref" href="#Arrays">Arrays</a>), the
+variable’s value is not unset (as it is when using ‘<samp class="samp">=</samp>’), and new
values are appended to the array beginning at one greater than the array’s
maximum index (for indexed arrays), or added as additional key-value pairs
in an associative array.
-When applied to a string-valued variable, <var>value</var> is expanded and
+When applied to a string-valued variable, <var class="var">value</var> is expanded and
appended to the variable’s value.
</p>
-<p>A variable can be assigned the <code>nameref</code> attribute using the
-<samp>-n</samp> option to the <code>declare</code> or <code>local</code> builtin commands
-(see <a href="#Bash-Builtins">Bash Builtin Commands</a>)
-to create a <em>nameref</em>, or a reference to another variable.
+<p>A variable can be assigned the <code class="code">nameref</code> attribute using the
+<samp class="option">-n</samp> option to the <code class="code">declare</code> or <code class="code">local</code> builtin commands
+(see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>)
+to create a <em class="dfn">nameref</em>, or a reference to another variable.
This allows variables to be manipulated indirectly.
Whenever the nameref variable is referenced, assigned to, unset, or has
its attributes modified (other than using or changing the nameref
For instance, if a variable name is passed to a shell function as its first
argument, running
</p><div class="example">
-<pre class="example">declare -n ref=$1
+<pre class="example-preformatted">declare -n ref=$1
</pre></div>
-<p>inside the function creates a nameref variable <code>ref</code> whose value is
+<p>inside the function creates a nameref variable <code class="env">ref</code> whose value is
the variable name passed as the first argument.
-References and assignments to <code>ref</code>, and changes to its attributes,
+References and assignments to <code class="env">ref</code>, and changes to its attributes,
are treated as references, assignments, and attribute modifications
-to the variable whose name was passed as <code>$1</code>.
+to the variable whose name was passed as <code class="code">$1</code>.
</p>
-<p>If the control variable in a <code>for</code> loop has the nameref attribute,
+<p>If the control variable in a <code class="code">for</code> loop has the nameref attribute,
the list of words can be a list of shell variables, and a name reference
will be established for each word in the list, in turn, when the loop is
executed.
Array variables cannot be given the nameref attribute.
However, nameref variables can reference array variables and subscripted
array variables.
-Namerefs can be unset using the <samp>-n</samp> option to the <code>unset</code> builtin
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-Otherwise, if <code>unset</code> is executed with the name of a nameref variable
+Namerefs can be unset using the <samp class="option">-n</samp> option to the <code class="code">unset</code> builtin
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+Otherwise, if <code class="code">unset</code> is executed with the name of a nameref variable
as an argument, the variable referenced by the nameref variable will be unset.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Positional-Parameters" accesskey="1">Positional Parameters</a></li>
<li><a href="#Special-Parameters" accesskey="2">Special Parameters</a></li>
</ul>
<hr>
-<div class="subsection" id="Positional-Parameters">
-<div class="header">
+<div class="subsection-level-extent" id="Positional-Parameters">
+<div class="nav-panel">
<p>
Next: <a href="#Special-Parameters" accesskey="n" rel="next">Special Parameters</a>, Up: <a href="#Shell-Parameters" accesskey="u" rel="up">Shell Parameters</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Positional-Parameters-1"></span><h4 class="subsection">3.4.1 Positional Parameters</h4>
-<span id="index-parameters_002c-positional"></span>
+<h4 class="subsection" id="Positional-Parameters-1"><span>3.4.1 Positional Parameters<a class="copiable-link" href="#Positional-Parameters-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-parameters_002c-positional"></a>
-<p>A <em>positional parameter</em> is a parameter denoted by one or more
-digits, other than the single digit <code>0</code>. Positional parameters are
+<p>A <em class="dfn">positional parameter</em> is a parameter denoted by one or more
+digits, other than the single digit <code class="code">0</code>. Positional parameters are
assigned from the shell’s arguments when it is invoked,
-and may be reassigned using the <code>set</code> builtin command.
-Positional parameter <code>N</code> may be referenced as <code>${N}</code>, or
-as <code>$N</code> when <code>N</code> consists of a single digit.
+and may be reassigned using the <code class="code">set</code> builtin command.
+Positional parameter <code class="code">N</code> may be referenced as <code class="code">${N}</code>, or
+as <code class="code">$N</code> when <code class="code">N</code> consists of a single digit.
Positional parameters may not be assigned to with assignment statements.
-The <code>set</code> and <code>shift</code> builtins are used to set and
-unset them (see <a href="#Shell-Builtin-Commands">Shell Builtin Commands</a>).
+The <code class="code">set</code> and <code class="code">shift</code> builtins are used to set and
+unset them (see <a class="pxref" href="#Shell-Builtin-Commands">Shell Builtin Commands</a>).
The positional parameters are
temporarily replaced when a shell function is executed
-(see <a href="#Shell-Functions">Shell Functions</a>).
+(see <a class="pxref" href="#Shell-Functions">Shell Functions</a>).
</p>
<p>When a positional parameter consisting of more than a single
digit is expanded, it must be enclosed in braces.
</p>
<hr>
</div>
-<div class="subsection" id="Special-Parameters">
-<div class="header">
+<div class="subsection-level-extent" id="Special-Parameters">
+<div class="nav-panel">
<p>
Previous: <a href="#Positional-Parameters" accesskey="p" rel="prev">Positional Parameters</a>, Up: <a href="#Shell-Parameters" accesskey="u" rel="up">Shell Parameters</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Special-Parameters-1"></span><h4 class="subsection">3.4.2 Special Parameters</h4>
-<span id="index-parameters_002c-special"></span>
+<h4 class="subsection" id="Special-Parameters-1"><span>3.4.2 Special Parameters<a class="copiable-link" href="#Special-Parameters-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-parameters_002c-special"></a>
<p>The shell treats several parameters specially. These parameters may
only be referenced; assignment to them is not allowed.
</p>
-<dl compact="compact">
-<dt id='index-_002a'><span><code>*</code><a href='#index-_002a' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_002a"></span>
+<dl class="vtable">
+<dt><a id="index-_002a"></a><span><code class="code">*</code><a class="copiable-link" href="#index-_002a"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_002a"></a>
<p>($*) Expands to the positional parameters, starting from one.
When the expansion is not within double quotes, each positional parameter
expands to a separate word.
are subject to further word splitting and filename expansion.
When the expansion occurs within double quotes, it expands to a single word
with the value of each parameter separated by the first character of the
-<code>IFS</code> special variable. That is, <code>"$*"</code> is equivalent
-to <code>"$1<var>c</var>$2<var>c</var>…"</code>, where <var>c</var>
-is the first character of the value of the <code>IFS</code>
+<code class="env">IFS</code> special variable. That is, <code class="code">"$*"</code> is equivalent
+to <code class="code">"$1<var class="var">c</var>$2<var class="var">c</var>…"</code>, where <var class="var">c</var>
+is the first character of the value of the <code class="code">IFS</code>
variable.
-If <code>IFS</code> is unset, the parameters are separated by spaces.
-If <code>IFS</code> is null, the parameters are joined without intervening
+If <code class="env">IFS</code> is unset, the parameters are separated by spaces.
+If <code class="env">IFS</code> is null, the parameters are joined without intervening
separators.
</p>
</dd>
-<dt id='index-_0040'><span><code>@</code><a href='#index-_0040' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_0040"></span>
+<dt><a id="index-_0040"></a><span><code class="code">@</code><a class="copiable-link" href="#index-_0040"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_0040"></a>
<p>($@) Expands to the positional parameters, starting from one.
In contexts where word splitting is performed, this expands each
positional parameter to a separate word; if not within double
When the
expansion occurs within double quotes, and word splitting is performed,
each parameter expands to a
-separate word. That is, <code>"$@"</code> is equivalent to
-<code>"$1" "$2" …</code>.
+separate word. That is, <code class="code">"$@"</code> is equivalent to
+<code class="code">"$1" "$2" …</code>.
If the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the original
word, and the expansion of the last parameter is joined with the last
part of the original word.
-When there are no positional parameters, <code>"$@"</code> and
-<code>$@</code>
+When there are no positional parameters, <code class="code">"$@"</code> and
+<code class="code">$@</code>
expand to nothing (i.e., they are removed).
</p>
</dd>
-<dt id='index-_0023'><span><code>#</code><a href='#index-_0023' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_0023"></span>
+<dt><a id="index-_0023"></a><span><code class="code">#</code><a class="copiable-link" href="#index-_0023"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_0023"></a>
<p>($#) Expands to the number of positional parameters in decimal.
</p>
</dd>
-<dt id='index-_003f'><span><code>?</code><a href='#index-_003f' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_003f"></span>
+<dt><a id="index-_003f"></a><span><code class="code">?</code><a class="copiable-link" href="#index-_003f"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_003f"></a>
<p>($?) Expands to the exit status of the most recently executed foreground
pipeline.
</p>
</dd>
-<dt id='index-_002d'><span><code>-</code><a href='#index-_002d' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_002d"></span>
+<dt><a id="index-_002d"></a><span><code class="code">-</code><a class="copiable-link" href="#index-_002d"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_002d"></a>
<p>($-, a hyphen.) Expands to the current option flags as specified upon
-invocation, by the <code>set</code>
+invocation, by the <code class="code">set</code>
builtin command, or those set by the shell itself
-(such as the <samp>-i</samp> option).
+(such as the <samp class="option">-i</samp> option).
</p>
</dd>
-<dt id='index-_0024'><span><code>$</code><a href='#index-_0024' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_0024"></span>
-<p>($$) Expands to the process <small>ID</small> of the shell. In a subshell, it
-expands to the process <small>ID</small> of the invoking shell, not the subshell.
+<dt><a id="index-_0024"></a><span><code class="code">$</code><a class="copiable-link" href="#index-_0024"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_0024"></a>
+<p>($$) Expands to the process <small class="sc">ID</small> of the shell. In a subshell, it
+expands to the process <small class="sc">ID</small> of the invoking shell, not the subshell.
</p>
</dd>
-<dt id='index-_0021-1'><span><code>!</code><a href='#index-_0021-1' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_0021"></span>
-<p>($!) Expands to the process <small>ID</small> of the job most recently placed into the
+<dt><a id="index-_0021-1"></a><span><code class="code">!</code><a class="copiable-link" href="#index-_0021-1"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_0021"></a>
+<p>($!) Expands to the process <small class="sc">ID</small> of the job most recently placed into the
background, whether executed as an asynchronous command or using
-the <code>bg</code> builtin (see <a href="#Job-Control-Builtins">Job Control Builtins</a>).
+the <code class="code">bg</code> builtin (see <a class="pxref" href="#Job-Control-Builtins">Job Control Builtins</a>).
</p>
</dd>
-<dt id='index-0'><span><code>0</code><a href='#index-0' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_00240"></span>
+<dt><a id="index-0"></a><span><code class="code">0</code><a class="copiable-link" href="#index-0"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_00240"></a>
<p>($0) Expands to the name of the shell or shell script. This is set at
shell initialization. If Bash is invoked with a file of commands
-(see <a href="#Shell-Scripts">Shell Scripts</a>), <code>$0</code> is set to the name of that file.
-If Bash is started with the <samp>-c</samp> option (see <a href="#Invoking-Bash">Invoking Bash</a>),
-then <code>$0</code> is set to the first argument after the string to be
+(see <a class="pxref" href="#Shell-Scripts">Shell Scripts</a>), <code class="code">$0</code> is set to the name of that file.
+If Bash is started with the <samp class="option">-c</samp> option (see <a class="pxref" href="#Invoking-Bash">Invoking Bash</a>),
+then <code class="code">$0</code> is set to the first argument after the string to be
executed, if one is present. Otherwise, it is set
to the filename used to invoke Bash, as given by argument zero.
</p></dd>
<hr>
</div>
</div>
-<div class="section" id="Shell-Expansions">
-<div class="header">
+<div class="section-level-extent" id="Shell-Expansions">
+<div class="nav-panel">
<p>
Next: <a href="#Redirections" accesskey="n" rel="next">Redirections</a>, Previous: <a href="#Shell-Parameters" accesskey="p" rel="prev">Shell Parameters</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Expansions-1"></span><h3 class="section">3.5 Shell Expansions</h3>
-<span id="index-expansion"></span>
+<h3 class="section" id="Shell-Expansions-1"><span>3.5 Shell Expansions<a class="copiable-link" href="#Shell-Expansions-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-expansion"></a>
<p>Expansion is performed on the command line after it has been split into
-<code>token</code>s. There are seven kinds of expansion performed:
-</p>
-<ul>
-<li> brace expansion
-</li><li> tilde expansion
-</li><li> parameter and variable expansion
-</li><li> command substitution
-</li><li> arithmetic expansion
-</li><li> word splitting
-</li><li> filename expansion
+<code class="code">token</code>s.
+Bash performs these expansions:
+</p>
+<ul class="itemize mark-bullet">
+<li>brace expansion
+</li><li>tilde expansion
+</li><li>parameter and variable expansion
+</li><li>command substitution
+</li><li>arithmetic expansion
+</li><li>word splitting
+</li><li>filename expansion
+</li><li>quote removal
</li></ul>
tilde expansion, parameter and variable expansion, arithmetic expansion,
and command substitution (done in a left-to-right fashion);
word splitting;
-and filename expansion.
+filename expansion;
+and quote removal.
</p>
<p>On systems that can support it, there is an additional expansion
-available: <em>process substitution</em>.
+available: <em class="dfn">process substitution</em>.
This is performed at the
same time as tilde, parameter, variable, and arithmetic expansion and
command substitution.
</p>
-<p>After these expansions are performed, quote characters present in the
-original word are removed unless they have been quoted themselves
-(<em>quote removal</em>). See <a href="#Quote-Removal">Quote Removal</a> for more details.
+<p><em class="dfn">Quote removal</em> is always performed last.
+It removes quote characters present in the original word,
+not ones resulting from one of the other expansions,
+unless they have been quoted themselves.
+See <a class="xref" href="#Quote-Removal">Quote Removal</a> for more details.
</p>
<p>Only brace expansion, word splitting, and filename expansion
can increase the number of words of the expansion; other expansions
expand a single word to a single word.
The only exceptions to this are the expansions of
-<code>"$@"</code> and <code>$*</code> (see <a href="#Special-Parameters">Special Parameters</a>), and
-<code>"${<var>name</var>[@]}"</code> and <code>${<var>name</var>[*]}</code>
-(see <a href="#Arrays">Arrays</a>).
+<code class="code">"$@"</code> and <code class="code">$*</code> (see <a class="pxref" href="#Special-Parameters">Special Parameters</a>), and
+<code class="code">"${<var class="var">name</var>[@]}"</code> and <code class="code">${<var class="var">name</var>[*]}</code>
+(see <a class="pxref" href="#Arrays">Arrays</a>).
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Brace-Expansion" accesskey="1">Brace Expansion</a></li>
<li><a href="#Tilde-Expansion" accesskey="2">Tilde Expansion</a></li>
<li><a href="#Shell-Parameter-Expansion" accesskey="3">Shell Parameter Expansion</a></li>
<li><a href="#Quote-Removal" accesskey="9">Quote Removal</a></li>
</ul>
<hr>
-<div class="subsection" id="Brace-Expansion">
-<div class="header">
+<div class="subsection-level-extent" id="Brace-Expansion">
+<div class="nav-panel">
<p>
Next: <a href="#Tilde-Expansion" accesskey="n" rel="next">Tilde Expansion</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Brace-Expansion-1"></span><h4 class="subsection">3.5.1 Brace Expansion</h4>
-<span id="index-brace-expansion"></span>
-<span id="index-expansion_002c-brace"></span>
+<h4 class="subsection" id="Brace-Expansion-1"><span>3.5.1 Brace Expansion<a class="copiable-link" href="#Brace-Expansion-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-brace-expansion"></a>
+<a class="index-entry-id" id="index-expansion_002c-brace"></a>
<p>Brace expansion is a mechanism by which arbitrary strings may be generated.
This mechanism is similar to
-<em>filename expansion</em> (see <a href="#Filename-Expansion">Filename Expansion</a>),
+<em class="dfn">filename expansion</em> (see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>),
but the filenames generated need not exist.
-Patterns to be brace expanded take the form of an optional <var>preamble</var>,
+Patterns to be brace expanded take the form of an optional <var class="var">preamble</var>,
followed by either a series of comma-separated strings or a sequence expression
between a pair of braces,
-followed by an optional <var>postscript</var>.
+followed by an optional <var class="var">postscript</var>.
The preamble is prefixed to each string contained within the braces, and
the postscript is then appended to each resulting string, expanding left
to right.
is preserved.
For example,
</p><div class="example">
-<pre class="example">bash$ echo a{d,c,b}e
+<pre class="example-preformatted">bash$ echo a{d,c,b}e
ade ace abe
</pre></div>
-<p>A sequence expression takes the form <code>{<var>x</var>..<var>y</var>[..<var>incr</var>]}</code>,
-where <var>x</var> and <var>y</var> are either integers or letters,
-and <var>incr</var>, an optional increment, is an integer.
+<p>A sequence expression takes the form <code class="code">{<var class="var">x</var>..<var class="var">y</var>[..<var class="var">incr</var>]}</code>,
+where <var class="var">x</var> and <var class="var">y</var> are either integers or letters,
+and <var class="var">incr</var>, an optional increment, is an integer.
When integers are supplied, the expression expands to each number between
-<var>x</var> and <var>y</var>, inclusive.
-Supplied integers may be prefixed with ‘<samp>0</samp>’ to force each term to have the
-same width.
-When either <var>x</var> or <var>y</var> begins with a zero, the shell
+<var class="var">x</var> and <var class="var">y</var>, inclusive.
+When either <var class="var">x</var> or <var class="var">y</var> begins with a zero, the shell
attempts to force all generated terms to contain the same number of digits,
zero-padding where necessary.
When letters are supplied, the expression expands to each character
-lexicographically between <var>x</var> and <var>y</var>, inclusive,
+lexicographically between <var class="var">x</var> and <var class="var">y</var>, inclusive,
using the default C locale.
-Note that both <var>x</var> and <var>y</var> must be of the same type
+Note that both <var class="var">x</var> and <var class="var">y</var> must be of the same type
(integer or letter).
When the increment is supplied, it is used as the difference between
each term. The default increment is 1 or -1 as appropriate.
sequence expression.
Any incorrectly formed brace expansion is left unchanged.
</p>
-<p>A { or ‘<samp>,</samp>’ may be quoted with a backslash to prevent its
+<p>A { or ‘<samp class="samp">,</samp>’ may be quoted with a backslash to prevent its
being considered part of a brace expression.
-To avoid conflicts with parameter expansion, the string ‘<samp>${</samp>’
+To avoid conflicts with parameter expansion, the string ‘<samp class="samp">${</samp>’
is not considered eligible for brace expansion,
-and inhibits brace expansion until the closing ‘<samp>}</samp>’.
+and inhibits brace expansion until the closing ‘<samp class="samp">}</samp>’.
</p>
<p>This construct is typically used as shorthand when the common
prefix of the strings to be generated is longer than in the
above example:
</p><div class="example">
-<pre class="example">mkdir /usr/local/src/bash/{old,new,dist,bugs}
+<pre class="example-preformatted">mkdir /usr/local/src/bash/{old,new,dist,bugs}
</pre></div>
<p>or
</p><div class="example">
-<pre class="example">chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}}
+<pre class="example-preformatted">chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}}
</pre></div>
<hr>
</div>
-<div class="subsection" id="Tilde-Expansion">
-<div class="header">
+<div class="subsection-level-extent" id="Tilde-Expansion">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Parameter-Expansion" accesskey="n" rel="next">Shell Parameter Expansion</a>, Previous: <a href="#Brace-Expansion" accesskey="p" rel="prev">Brace Expansion</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Tilde-Expansion-1"></span><h4 class="subsection">3.5.2 Tilde Expansion</h4>
-<span id="index-tilde-expansion"></span>
-<span id="index-expansion_002c-tilde"></span>
+<h4 class="subsection" id="Tilde-Expansion-1"><span>3.5.2 Tilde Expansion<a class="copiable-link" href="#Tilde-Expansion-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-tilde-expansion"></a>
+<a class="index-entry-id" id="index-expansion_002c-tilde"></a>
-<p>If a word begins with an unquoted tilde character (‘<samp>~</samp>’), all of the
+<p>If a word begins with an unquoted tilde character (‘<samp class="samp">~</samp>’), all of the
characters up to the first unquoted slash (or all characters,
-if there is no unquoted slash) are considered a <em>tilde-prefix</em>.
+if there is no unquoted slash) are considered a <em class="dfn">tilde-prefix</em>.
If none of the characters in the tilde-prefix are quoted, the
characters in the tilde-prefix following the tilde are treated as a
-possible <em>login name</em>.
+possible <em class="dfn">login name</em>.
If this login name is the null string, the tilde is replaced with the
-value of the <code>HOME</code> shell variable.
-If <code>HOME</code> is unset, the home directory of the user executing the
+value of the <code class="env">HOME</code> shell variable.
+If <code class="env">HOME</code> is unset, the home directory of the user executing the
shell is substituted instead.
Otherwise, the tilde-prefix is replaced with the home directory
associated with the specified login name.
</p>
-<p>If the tilde-prefix is ‘<samp>~+</samp>’, the value of
-the shell variable <code>PWD</code> replaces the tilde-prefix.
-If the tilde-prefix is ‘<samp>~-</samp>’, the value of the shell variable
-<code>OLDPWD</code>, if it is set, is substituted.
+<p>If the tilde-prefix is ‘<samp class="samp">~+</samp>’, the value of
+the shell variable <code class="env">PWD</code> replaces the tilde-prefix.
+If the tilde-prefix is ‘<samp class="samp">~-</samp>’, the value of the shell variable
+<code class="env">OLDPWD</code>, if it is set, is substituted.
</p>
<p>If the characters following the tilde in the tilde-prefix consist of a
-number <var>N</var>, optionally prefixed by a ‘<samp>+</samp>’ or a ‘<samp>-</samp>’,
+number <var class="var">N</var>, optionally prefixed by a ‘<samp class="samp">+</samp>’ or a ‘<samp class="samp">-</samp>’,
the tilde-prefix is replaced with the
corresponding element from the directory stack, as it would be displayed
-by the <code>dirs</code> builtin invoked with the characters following tilde
-in the tilde-prefix as an argument (see <a href="#The-Directory-Stack">The Directory Stack</a>).
+by the <code class="code">dirs</code> builtin invoked with the characters following tilde
+in the tilde-prefix as an argument (see <a class="pxref" href="#The-Directory-Stack">The Directory Stack</a>).
If the tilde-prefix, sans the tilde, consists of a number without a
-leading ‘<samp>+</samp>’ or ‘<samp>-</samp>’, ‘<samp>+</samp>’ is assumed.
+leading ‘<samp class="samp">+</samp>’ or ‘<samp class="samp">-</samp>’, ‘<samp class="samp">+</samp>’ is assumed.
</p>
<p>If the login name is invalid, or the tilde expansion fails, the word is
left unchanged.
</p>
<p>Each variable assignment is checked for unquoted tilde-prefixes immediately
-following a ‘<samp>:</samp>’ or the first ‘<samp>=</samp>’.
+following a ‘<samp class="samp">:</samp>’ or the first ‘<samp class="samp">=</samp>’.
In these cases, tilde expansion is also performed.
Consequently, one may use filenames with tildes in assignments to
-<code>PATH</code>, <code>MAILPATH</code>, and <code>CDPATH</code>,
+<code class="env">PATH</code>, <code class="env">MAILPATH</code>, and <code class="env">CDPATH</code>,
and the shell assigns the expanded value.
</p>
<p>The following table shows how Bash treats unquoted tilde-prefixes:
</p>
-<dl compact="compact">
-<dt><span><code>~</code></span></dt>
-<dd><p>The value of <code>$HOME</code>
+<dl class="table">
+<dt><code class="code">~</code></dt>
+<dd><p>The value of <code class="code">$HOME</code>
</p></dd>
-<dt><span><code>~/foo</code></span></dt>
-<dd><p><samp>$HOME/foo</samp>
+<dt><code class="code">~/foo</code></dt>
+<dd><p><samp class="file">$HOME/foo</samp>
</p>
</dd>
-<dt><span><code>~fred/foo</code></span></dt>
-<dd><p>The subdirectory <code>foo</code> of the home directory of the user
-<code>fred</code>
+<dt><code class="code">~fred/foo</code></dt>
+<dd><p>The subdirectory <code class="code">foo</code> of the home directory of the user
+<code class="code">fred</code>
</p>
</dd>
-<dt><span><code>~+/foo</code></span></dt>
-<dd><p><samp>$PWD/foo</samp>
+<dt><code class="code">~+/foo</code></dt>
+<dd><p><samp class="file">$PWD/foo</samp>
</p>
</dd>
-<dt><span><code>~-/foo</code></span></dt>
-<dd><p><samp>${OLDPWD-'~-'}/foo</samp>
+<dt><code class="code">~-/foo</code></dt>
+<dd><p><samp class="file">${OLDPWD-'~-'}/foo</samp>
</p>
</dd>
-<dt><span><code>~<var>N</var></code></span></dt>
-<dd><p>The string that would be displayed by ‘<samp>dirs +<var>N</var></samp>’
+<dt><code class="code">~<var class="var">N</var></code></dt>
+<dd><p>The string that would be displayed by ‘<samp class="samp">dirs +<var class="var">N</var></samp>’
</p>
</dd>
-<dt><span><code>~+<var>N</var></code></span></dt>
-<dd><p>The string that would be displayed by ‘<samp>dirs +<var>N</var></samp>’
+<dt><code class="code">~+<var class="var">N</var></code></dt>
+<dd><p>The string that would be displayed by ‘<samp class="samp">dirs +<var class="var">N</var></samp>’
</p>
</dd>
-<dt><span><code>~-<var>N</var></code></span></dt>
-<dd><p>The string that would be displayed by ‘<samp>dirs -<var>N</var></samp>’
+<dt><code class="code">~-<var class="var">N</var></code></dt>
+<dd><p>The string that would be displayed by ‘<samp class="samp">dirs -<var class="var">N</var></samp>’
</p></dd>
</dl>
<p>Bash also performs tilde expansion on words satisfying the conditions of
-variable assignments (see <a href="#Shell-Parameters">Shell Parameters</a>)
+variable assignments (see <a class="pxref" href="#Shell-Parameters">Shell Parameters</a>)
when they appear as arguments to simple commands.
Bash does not do this, except for the declaration commands listed
-above, when in <small>POSIX</small> mode.
+above, when in <small class="sc">POSIX</small> mode.
</p>
<hr>
</div>
-<div class="subsection" id="Shell-Parameter-Expansion">
-<div class="header">
+<div class="subsection-level-extent" id="Shell-Parameter-Expansion">
+<div class="nav-panel">
<p>
Next: <a href="#Command-Substitution" accesskey="n" rel="next">Command Substitution</a>, Previous: <a href="#Tilde-Expansion" accesskey="p" rel="prev">Tilde Expansion</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Parameter-Expansion-1"></span><h4 class="subsection">3.5.3 Shell Parameter Expansion</h4>
-<span id="index-parameter-expansion"></span>
-<span id="index-expansion_002c-parameter"></span>
+<h4 class="subsection" id="Shell-Parameter-Expansion-1"><span>3.5.3 Shell Parameter Expansion<a class="copiable-link" href="#Shell-Parameter-Expansion-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-parameter-expansion"></a>
+<a class="index-entry-id" id="index-expansion_002c-parameter"></a>
-<p>The ‘<samp>$</samp>’ character introduces parameter expansion,
+<p>The ‘<samp class="samp">$</samp>’ character introduces parameter expansion,
command substitution, or arithmetic expansion. The parameter name
or symbol to be expanded may be enclosed in braces, which
are optional but serve to protect the variable to be expanded from
characters immediately following it which could be
interpreted as part of the name.
</p>
-<p>When braces are used, the matching ending brace is the first ‘<samp>}</samp>’
+<p>When braces are used, the matching ending brace is the first ‘<samp class="samp">}</samp>’
not escaped by a backslash or within a quoted string, and not within an
embedded arithmetic expansion, command substitution, or parameter
expansion.
</p>
-<p>The basic form of parameter expansion is ${<var>parameter</var>}.
-The value of <var>parameter</var> is substituted.
-The <var>parameter</var> is a shell parameter as described above
-(see <a href="#Shell-Parameters">Shell Parameters</a>) or an array reference (see <a href="#Arrays">Arrays</a>).
-The braces are required when <var>parameter</var>
+<p>The basic form of parameter expansion is ${<var class="var">parameter</var>}.
+The value of <var class="var">parameter</var> is substituted.
+The <var class="var">parameter</var> is a shell parameter as described above
+(see <a class="pxref" href="#Shell-Parameters">Shell Parameters</a>) or an array reference (see <a class="pxref" href="#Arrays">Arrays</a>).
+The braces are required when <var class="var">parameter</var>
is a positional parameter with more than one digit,
-or when <var>parameter</var> is followed by a character that is not to be
+or when <var class="var">parameter</var> is followed by a character that is not to be
interpreted as part of its name.
</p>
-<p>If the first character of <var>parameter</var> is an exclamation point (!),
-and <var>parameter</var> is not a nameref,
+<p>If the first character of <var class="var">parameter</var> is an exclamation point (!),
+and <var class="var">parameter</var> is not a nameref,
it introduces a level of indirection.
Bash uses the value formed by expanding the rest of
-<var>parameter</var> as the new <var>parameter</var>; this is then
+<var class="var">parameter</var> as the new <var class="var">parameter</var>; this is then
expanded and that value is used in the rest of the expansion, rather
-than the expansion of the original <var>parameter</var>.
-This is known as <code>indirect expansion</code>.
+than the expansion of the original <var class="var">parameter</var>.
+This is known as <code class="code">indirect expansion</code>.
The value is subject to tilde expansion,
parameter expansion, command substitution, and arithmetic expansion.
-If <var>parameter</var> is a nameref, this expands to the name of the
-variable referenced by <var>parameter</var> instead of performing the
+If <var class="var">parameter</var> is a nameref, this expands to the name of the
+variable referenced by <var class="var">parameter</var> instead of performing the
complete indirect expansion.
-The exceptions to this are the expansions of ${!<var>prefix</var>*}
-and ${!<var>name</var>[@]}
+The exceptions to this are the expansions of ${!<var class="var">prefix</var>*}
+and ${!<var class="var">name</var>[@]}
described below.
The exclamation point must immediately follow the left brace in order to
introduce indirection.
</p>
-<p>In each of the cases below, <var>word</var> is subject to tilde expansion,
+<p>In each of the cases below, <var class="var">word</var> is subject to tilde expansion,
parameter expansion, command substitution, and arithmetic expansion.
</p>
<p>When not performing substring expansion, using the forms described
-below (e.g., ‘<samp>:-</samp>’), Bash tests for a parameter that is unset or null.
+below (e.g., ‘<samp class="samp">:-</samp>’), Bash tests for a parameter that is unset or null.
Omitting the colon results in a test only for a parameter that is unset.
Put another way, if the colon is included,
-the operator tests for both <var>parameter</var>’s existence and that its value
+the operator tests for both <var class="var">parameter</var>’s existence and that its value
is not null; if the colon is omitted, the operator tests only for existence.
</p>
-<dl compact="compact">
-<dt><span><code>${<var>parameter</var>:-<var>word</var>}</code></span></dt>
-<dd><p>If <var>parameter</var> is unset or null, the expansion of
-<var>word</var> is substituted. Otherwise, the value of
-<var>parameter</var> is substituted.
+<dl class="table">
+<dt><code class="code">${<var class="var">parameter</var>:−<var class="var">word</var>}</code></dt>
+<dd><p>If <var class="var">parameter</var> is unset or null, the expansion of
+<var class="var">word</var> is substituted. Otherwise, the value of
+<var class="var">parameter</var> is substituted.
</p>
<div class="example">
-<pre class="example">$ v=123
+<pre class="example-preformatted">$ v=123
$ echo ${v-unset}
123
$ echo ${v:-unset-or-null}
</pre></div>
</dd>
-<dt><span><code>${<var>parameter</var>:=<var>word</var>}</code></span></dt>
-<dd><p>If <var>parameter</var>
-is unset or null, the expansion of <var>word</var>
-is assigned to <var>parameter</var>.
-The value of <var>parameter</var> is then substituted.
+<dt><code class="code">${<var class="var">parameter</var>:=<var class="var">word</var>}</code></dt>
+<dd><p>If <var class="var">parameter</var>
+is unset or null, the expansion of <var class="var">word</var>
+is assigned to <var class="var">parameter</var>.
+The value of <var class="var">parameter</var> is then substituted.
Positional parameters and special parameters may not be assigned to
in this way.
</p>
<div class="example">
-<pre class="example">$ var=
+<pre class="example-preformatted">$ var=
$ : ${var:=DEFAULT}
$ echo $var
DEFAULT
</pre></div>
</dd>
-<dt><span><code>${<var>parameter</var>:?<var>word</var>}</code></span></dt>
-<dd><p>If <var>parameter</var>
-is null or unset, the expansion of <var>word</var> (or a message
-to that effect if <var>word</var>
+<dt><code class="code">${<var class="var">parameter</var>:?<var class="var">word</var>}</code></dt>
+<dd><p>If <var class="var">parameter</var>
+is null or unset, the expansion of <var class="var">word</var> (or a message
+to that effect if <var class="var">word</var>
is not present) is written to the standard error and the shell, if it
-is not interactive, exits. Otherwise, the value of <var>parameter</var> is
+is not interactive, exits. Otherwise, the value of <var class="var">parameter</var> is
substituted.
</p>
<div class="example">
-<pre class="example">$ var=
+<pre class="example-preformatted">$ var=
$ : ${var:?var is unset or null}
bash: var: var is unset or null
</pre></div>
</dd>
-<dt><span><code>${<var>parameter</var>:+<var>word</var>}</code></span></dt>
-<dd><p>If <var>parameter</var>
+<dt><code class="code">${<var class="var">parameter</var>:+<var class="var">word</var>}</code></dt>
+<dd><p>If <var class="var">parameter</var>
is null or unset, nothing is substituted, otherwise the expansion of
-<var>word</var> is substituted.
+<var class="var">word</var> is substituted.
</p>
<div class="example">
-<pre class="example">$ var=123
+<pre class="example-preformatted">$ var=123
$ echo ${var:+var is set and not null}
var is set and not null
</pre></div>
</dd>
-<dt><span><code>${<var>parameter</var>:<var>offset</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>:<var>offset</var>:<var>length</var>}</code></span></dt>
+<dt><code class="code">${<var class="var">parameter</var>:<var class="var">offset</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>:<var class="var">offset</var>:<var class="var">length</var>}</code></dt>
<dd><p>This is referred to as Substring Expansion.
-It expands to up to <var>length</var> characters of the value of <var>parameter</var>
-starting at the character specified by <var>offset</var>.
-If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’, an indexed array subscripted by
-‘<samp>@</samp>’ or ‘<samp>*</samp>’, or an associative array name, the results differ as
+It expands to up to <var class="var">length</var> characters of the value of <var class="var">parameter</var>
+starting at the character specified by <var class="var">offset</var>.
+If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’, an indexed array subscripted by
+‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’, or an associative array name, the results differ as
described below.
-If <var>length</var> is omitted, it expands to the substring of the value of
-<var>parameter</var> starting at the character specified by <var>offset</var>
+If <var class="var">length</var> is omitted, it expands to the substring of the value of
+<var class="var">parameter</var> starting at the character specified by <var class="var">offset</var>
and extending to the end of the value.
-<var>length</var> and <var>offset</var> are arithmetic expressions
-(see <a href="#Shell-Arithmetic">Shell Arithmetic</a>).
+<var class="var">length</var> and <var class="var">offset</var> are arithmetic expressions
+(see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>).
</p>
-<p>If <var>offset</var> evaluates to a number less than zero, the value
+<p>If <var class="var">offset</var> evaluates to a number less than zero, the value
is used as an offset in characters
-from the end of the value of <var>parameter</var>.
-If <var>length</var> evaluates to a number less than zero,
+from the end of the value of <var class="var">parameter</var>.
+If <var class="var">length</var> evaluates to a number less than zero,
it is interpreted as an offset in characters
-from the end of the value of <var>parameter</var> rather than
+from the end of the value of <var class="var">parameter</var> rather than
a number of characters, and the expansion is the characters between
-<var>offset</var> and that result.
+<var class="var">offset</var> and that result.
Note that a negative offset must be separated from the colon by at least
-one space to avoid being confused with the ‘<samp>:-</samp>’ expansion.
+one space to avoid being confused with the ‘<samp class="samp">:-</samp>’ expansion.
</p>
<p>Here are some examples illustrating substring expansion on parameters and
subscripted arrays:
$ echo ${array[0]: -7:-2}
bcdef
</pre>
-<p>If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’, the result is <var>length</var>
-positional parameters beginning at <var>offset</var>.
-A negative <var>offset</var> is taken relative to one greater than the greatest
+<p>If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’, the result is <var class="var">length</var>
+positional parameters beginning at <var class="var">offset</var>.
+A negative <var class="var">offset</var> is taken relative to one greater than the greatest
positional parameter, so an offset of -1 evaluates to the last positional
parameter (or 0 if there are no positional parameters).
-It is an expansion error if <var>length</var> evaluates to a number less than zero.
+It is an expansion error if <var class="var">length</var> evaluates to a number less than zero.
</p>
<p>The following examples illustrate substring expansion using positional
parameters:
$ echo ${@: -7:0}
</pre>
-<p>If <var>parameter</var> is an indexed array name subscripted
-by ‘<samp>@</samp>’ or ‘<samp>*</samp>’, the result is the <var>length</var>
-members of the array beginning with <code>${<var>parameter</var>[<var>offset</var>]}</code>.
-A negative <var>offset</var> is taken relative to one greater than the maximum
+<p>If <var class="var">parameter</var> is an indexed array name subscripted
+by ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’, the result is the <var class="var">length</var>
+members of the array beginning with <code class="code">${<var class="var">parameter</var>[<var class="var">offset</var>]}</code>.
+A negative <var class="var">offset</var> is taken relative to one greater than the maximum
index of the specified array.
-It is an expansion error if <var>length</var> evaluates to a number less than zero.
+It is an expansion error if <var class="var">length</var> evaluates to a number less than zero.
</p>
<p>These examples show how you can use substring expansion with indexed
arrays:
</p>
<p>Substring indexing is zero-based unless the positional parameters
are used, in which case the indexing starts at 1 by default.
-If <var>offset</var> is 0, and the positional parameters are used, <code>$0</code> is
+If <var class="var">offset</var> is 0, and the positional parameters are used, <code class="code">$0</code> is
prefixed to the list.
</p>
</dd>
-<dt><span><code>${!<var>prefix</var>*}</code></span></dt>
-<dt><span><code>${!<var>prefix</var>@}</code></span></dt>
-<dd><p>Expands to the names of variables whose names begin with <var>prefix</var>,
-separated by the first character of the <code>IFS</code> special variable.
-When ‘<samp>@</samp>’ is used and the expansion appears within double quotes, each
+<dt><code class="code">${!<var class="var">prefix</var>*}</code></dt>
+<dt><code class="code">${!<var class="var">prefix</var>@}</code></dt>
+<dd><p>Expands to the names of variables whose names begin with <var class="var">prefix</var>,
+separated by the first character of the <code class="env">IFS</code> special variable.
+When ‘<samp class="samp">@</samp>’ is used and the expansion appears within double quotes, each
variable name expands to a separate word.
</p>
</dd>
-<dt><span><code>${!<var>name</var>[@]}</code></span></dt>
-<dt><span><code>${!<var>name</var>[*]}</code></span></dt>
-<dd><p>If <var>name</var> is an array variable, expands to the list of array indices
-(keys) assigned in <var>name</var>.
-If <var>name</var> is not an array, expands to 0 if <var>name</var> is set and null
+<dt><code class="code">${!<var class="var">name</var>[@]}</code></dt>
+<dt><code class="code">${!<var class="var">name</var>[*]}</code></dt>
+<dd><p>If <var class="var">name</var> is an array variable, expands to the list of array indices
+(keys) assigned in <var class="var">name</var>.
+If <var class="var">name</var> is not an array, expands to 0 if <var class="var">name</var> is set and null
otherwise.
-When ‘<samp>@</samp>’ is used and the expansion appears within double quotes, each
+When ‘<samp class="samp">@</samp>’ is used and the expansion appears within double quotes, each
key expands to a separate word.
</p>
</dd>
-<dt><span><code>${#<var>parameter</var>}</code></span></dt>
-<dd><p>The length in characters of the expanded value of <var>parameter</var> is
+<dt><code class="code">${#<var class="var">parameter</var>}</code></dt>
+<dd><p>The length in characters of the expanded value of <var class="var">parameter</var> is
substituted.
-If <var>parameter</var> is ‘<samp>*</samp>’ or ‘<samp>@</samp>’, the value substituted
+If <var class="var">parameter</var> is ‘<samp class="samp">*</samp>’ or ‘<samp class="samp">@</samp>’, the value substituted
is the number of positional parameters.
-If <var>parameter</var> is an array name subscripted by ‘<samp>*</samp>’ or ‘<samp>@</samp>’,
+If <var class="var">parameter</var> is an array name subscripted by ‘<samp class="samp">*</samp>’ or ‘<samp class="samp">@</samp>’,
the value substituted is the number of elements in the array.
-If <var>parameter</var>
+If <var class="var">parameter</var>
is an indexed array name subscripted by a negative number, that number is
interpreted as relative to one greater than the maximum index of
-<var>parameter</var>, so negative indices count back from the end of the
+<var class="var">parameter</var>, so negative indices count back from the end of the
array, and an index of -1 references the last element.
</p>
</dd>
-<dt><span><code>${<var>parameter</var>#<var>word</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>##<var>word</var>}</code></span></dt>
-<dd><p>The <var>word</var>
+<dt><code class="code">${<var class="var">parameter</var>#<var class="var">word</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>##<var class="var">word</var>}</code></dt>
+<dd><p>The <var class="var">word</var>
is expanded to produce a pattern and matched according to the rules
-described below (see <a href="#Pattern-Matching">Pattern Matching</a>). If the pattern matches
-the beginning of the expanded value of <var>parameter</var>,
-then the result of the expansion is the expanded value of <var>parameter</var>
-with the shortest matching pattern (the ‘<samp>#</samp>’ case) or the
-longest matching pattern (the ‘<samp>##</samp>’ case) deleted.
-If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+described below (see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>). If the pattern matches
+the beginning of the expanded value of <var class="var">parameter</var>,
+then the result of the expansion is the expanded value of <var class="var">parameter</var>
+with the shortest matching pattern (the ‘<samp class="samp">#</samp>’ case) or the
+longest matching pattern (the ‘<samp class="samp">##</samp>’ case) deleted.
+If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the pattern removal operation is applied to each positional
parameter in turn, and the expansion is the resultant list.
-If <var>parameter</var> is an array variable subscripted with
-‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">parameter</var> is an array variable subscripted with
+‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the pattern removal operation is applied to each member of the
array in turn, and the expansion is the resultant list.
</p>
</dd>
-<dt><span><code>${<var>parameter</var>%<var>word</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>%%<var>word</var>}</code></span></dt>
-<dd><p>The <var>word</var>
+<dt><code class="code">${<var class="var">parameter</var>%<var class="var">word</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>%%<var class="var">word</var>}</code></dt>
+<dd><p>The <var class="var">word</var>
is expanded to produce a pattern and matched according to the rules
-described below (see <a href="#Pattern-Matching">Pattern Matching</a>).
+described below (see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>).
If the pattern matches a trailing portion of the expanded value of
-<var>parameter</var>, then the result of the expansion is the value of
-<var>parameter</var> with the shortest matching pattern (the ‘<samp>%</samp>’ case)
-or the longest matching pattern (the ‘<samp>%%</samp>’ case) deleted.
-If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+<var class="var">parameter</var>, then the result of the expansion is the value of
+<var class="var">parameter</var> with the shortest matching pattern (the ‘<samp class="samp">%</samp>’ case)
+or the longest matching pattern (the ‘<samp class="samp">%%</samp>’ case) deleted.
+If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the pattern removal operation is applied to each positional
parameter in turn, and the expansion is the resultant list.
-If <var>parameter</var>
-is an array variable subscripted with ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">parameter</var>
+is an array variable subscripted with ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the pattern removal operation is applied to each member of the
array in turn, and the expansion is the resultant list.
</p>
</dd>
-<dt><span><code>${<var>parameter</var>/<var>pattern</var>/<var>string</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>//<var>pattern</var>/<var>string</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>/#<var>pattern</var>/<var>string</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>/%<var>pattern</var>/<var>string</var>}</code></span></dt>
-<dd><p>The <var>pattern</var> is expanded to produce a pattern just as in
+<dt><code class="code">${<var class="var">parameter</var>/<var class="var">pattern</var>/<var class="var">string</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>//<var class="var">pattern</var>/<var class="var">string</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>/#<var class="var">pattern</var>/<var class="var">string</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>/%<var class="var">pattern</var>/<var class="var">string</var>}</code></dt>
+<dd><p>The <var class="var">pattern</var> is expanded to produce a pattern just as in
filename expansion.
-<var>Parameter</var> is expanded and the longest match of <var>pattern</var>
-against its value is replaced with <var>string</var>.
-<var>string</var> undergoes tilde expansion, parameter and variable expansion,
+<var class="var">Parameter</var> is expanded and the longest match of <var class="var">pattern</var>
+against its value is replaced with <var class="var">string</var>.
+<var class="var">string</var> undergoes tilde expansion, parameter and variable expansion,
arithmetic expansion, command and process substitution, and quote removal.
The match is performed according to the rules described below
-(see <a href="#Pattern-Matching">Pattern Matching</a>).
+(see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>).
</p>
<p>In the first form above, only the first match is replaced.
-If there are two slashes separating <var>parameter</var> and <var>pattern</var>
-(the second form above), all matches of <var>pattern</var> are
-replaced with <var>string</var>.
-If <var>pattern</var> is preceded by ‘<samp>#</samp>’ (the third form above),
-it must match at the beginning of the expanded value of <var>parameter</var>.
-If <var>pattern</var> is preceded by ‘<samp>%</samp>’ (the fourth form above),
-it must match at the end of the expanded value of <var>parameter</var>.
-If the expansion of <var>string</var> is null,
-matches of <var>pattern</var> are deleted.
-If <var>string</var> is null,
-matches of <var>pattern</var> are deleted
-and the ‘<samp>/</samp>’ following <var>pattern</var> may be omitted.
-</p>
-<p>If the <code>patsub_replacement</code> shell option is enabled using <code>shopt</code>,
-any unquoted instances of ‘<samp>&</samp>’ in <var>string</var> are replaced with the
-matching portion of <var>pattern</var>.
-This is intended to duplicate a common <code>sed</code> idiom.
-</p>
-<p>Quoting any part of <var>string</var> inhibits replacement in the
+If there are two slashes separating <var class="var">parameter</var> and <var class="var">pattern</var>
+(the second form above), all matches of <var class="var">pattern</var> are
+replaced with <var class="var">string</var>.
+If <var class="var">pattern</var> is preceded by ‘<samp class="samp">#</samp>’ (the third form above),
+it must match at the beginning of the expanded value of <var class="var">parameter</var>.
+If <var class="var">pattern</var> is preceded by ‘<samp class="samp">%</samp>’ (the fourth form above),
+it must match at the end of the expanded value of <var class="var">parameter</var>.
+If the expansion of <var class="var">string</var> is null,
+matches of <var class="var">pattern</var> are deleted.
+If <var class="var">string</var> is null,
+matches of <var class="var">pattern</var> are deleted
+and the ‘<samp class="samp">/</samp>’ following <var class="var">pattern</var> may be omitted.
+</p>
+<p>If the <code class="code">patsub_replacement</code> shell option is enabled using <code class="code">shopt</code>,
+any unquoted instances of ‘<samp class="samp">&</samp>’ in <var class="var">string</var> are replaced with the
+matching portion of <var class="var">pattern</var>.
+This is intended to duplicate a common <code class="code">sed</code> idiom.
+</p>
+<p>Quoting any part of <var class="var">string</var> inhibits replacement in the
expansion of the quoted portion, including replacement strings stored
in shell variables.
-Backslash will escape ‘<samp>&</samp>’ in <var>string</var>; the backslash is removed
-in order to permit a literal ‘<samp>&</samp>’ in the replacement string.
-Users should take care if <var>string</var> is double-quoted to avoid
+Backslash will escape ‘<samp class="samp">&</samp>’ in <var class="var">string</var>; the backslash is removed
+in order to permit a literal ‘<samp class="samp">&</samp>’ in the replacement string.
+Users should take care if <var class="var">string</var> is double-quoted to avoid
unwanted interactions between the backslash and double-quoting, since
backslash has special meaning within double quotes.
-Pattern substitution performs the check for unquoted ‘<samp>&</samp>’ after
-expanding <var>string</var>,
-so users should ensure to properly quote any occurrences of ‘<samp>&</samp>’
+Pattern substitution performs the check for unquoted ‘<samp class="samp">&</samp>’ after
+expanding <var class="var">string</var>,
+so users should ensure to properly quote any occurrences of ‘<samp class="samp">&</samp>’
they want to be taken literally in the replacement
-and ensure any instances of ‘<samp>&</samp>’ they want to be replaced are unquoted.
+and ensure any instances of ‘<samp class="samp">&</samp>’ they want to be replaced are unquoted.
</p>
<p>For instance,
</p>
<div class="example">
-<pre class="example">var=abcdef
+<pre class="example-preformatted">var=abcdef
rep='& '
echo ${var/abc/& }
echo "${var/abc/& }"
<p>will display four lines of "abc def", while
</p>
<div class="example">
-<pre class="example">var=abcdef
+<pre class="example-preformatted">var=abcdef
rep='& '
echo ${var/abc/\& }
echo "${var/abc/\& }"
the expansion is performed in a
context that doesn’t take any enclosing double quotes into account.
</p>
-<p>Since backslash can escape ‘<samp>&</samp>’, it can also escape a backslash in
+<p>Since backslash can escape ‘<samp class="samp">&</samp>’, it can also escape a backslash in
the replacement string.
-This means that ‘<samp>\\</samp>’ will insert a literal
-backslash into the replacement, so these two <code>echo</code> commands
+This means that ‘<samp class="samp">\\</samp>’ will insert a literal
+backslash into the replacement, so these two <code class="code">echo</code> commands
</p>
<div class="example">
-<pre class="example">var=abcdef
+<pre class="example-preformatted">var=abcdef
rep='\\&xyz'
echo ${var/abc/\\&xyz}
echo ${var/abc/$rep}
</pre></div>
-<p>will both output ‘<samp>\abcxyzdef</samp>’.
+<p>will both output ‘<samp class="samp">\abcxyzdef</samp>’.
</p>
-<p>It should rarely be necessary to enclose only <var>string</var> in double
+<p>It should rarely be necessary to enclose only <var class="var">string</var> in double
quotes.
</p>
-<p>If the <code>nocasematch</code> shell option
-(see the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+<p>If the <code class="code">nocasematch</code> shell option
+(see the description of <code class="code">shopt</code> in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
is enabled, the match is performed without regard to the case
of alphabetic characters.
-If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the substitution operation is applied to each positional
parameter in turn, and the expansion is the resultant list.
-If <var>parameter</var>
-is an array variable subscripted with ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">parameter</var>
+is an array variable subscripted with ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the substitution operation is applied to each member of the
array in turn, and the expansion is the resultant list.
</p>
</dd>
-<dt><span><code>${<var>parameter</var>^<var>pattern</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>^^<var>pattern</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>,<var>pattern</var>}</code></span></dt>
-<dt><span><code>${<var>parameter</var>,,<var>pattern</var>}</code></span></dt>
-<dd><p>This expansion modifies the case of alphabetic characters in <var>parameter</var>.
-The <var>pattern</var> is expanded to produce a pattern just as in
+<dt><code class="code">${<var class="var">parameter</var>^<var class="var">pattern</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>^^<var class="var">pattern</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>,<var class="var">pattern</var>}</code></dt>
+<dt><code class="code">${<var class="var">parameter</var>,,<var class="var">pattern</var>}</code></dt>
+<dd><p>This expansion modifies the case of alphabetic characters in <var class="var">parameter</var>.
+The <var class="var">pattern</var> is expanded to produce a pattern just as in
filename expansion.
-Each character in the expanded value of <var>parameter</var> is tested against
-<var>pattern</var>, and, if it matches the pattern, its case is converted.
+Each character in the expanded value of <var class="var">parameter</var> is tested against
+<var class="var">pattern</var>, and, if it matches the pattern, its case is converted.
The pattern should not attempt to match more than one character.
</p>
-<p>The ‘<samp>^</samp>’ operator converts lowercase letters matching <var>pattern</var>
-to uppercase; the ‘<samp>,</samp>’ operator converts matching uppercase letters
+<p>The ‘<samp class="samp">^</samp>’ operator converts lowercase letters matching <var class="var">pattern</var>
+to uppercase; the ‘<samp class="samp">,</samp>’ operator converts matching uppercase letters
to lowercase.
-The ‘<samp>^^</samp>’ and ‘<samp>,,</samp>’ expansions convert each matched character in the
-expanded value; the ‘<samp>^</samp>’ and ‘<samp>,</samp>’ expansions match and convert only
+The ‘<samp class="samp">^^</samp>’ and ‘<samp class="samp">,,</samp>’ expansions convert each matched character in the
+expanded value; the ‘<samp class="samp">^</samp>’ and ‘<samp class="samp">,</samp>’ expansions match and convert only
the first character in the expanded value.
-If <var>pattern</var> is omitted, it is treated like a ‘<samp>?</samp>’, which matches
+If <var class="var">pattern</var> is omitted, it is treated like a ‘<samp class="samp">?</samp>’, which matches
every character.
</p>
-<p>If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+<p>If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the case modification operation is applied to each positional
parameter in turn, and the expansion is the resultant list.
-If <var>parameter</var>
-is an array variable subscripted with ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">parameter</var>
+is an array variable subscripted with ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the case modification operation is applied to each member of the
array in turn, and the expansion is the resultant list.
</p>
</dd>
-<dt><span><code>${<var>parameter</var>@<var>operator</var>}</code></span></dt>
-<dd><p>The expansion is either a transformation of the value of <var>parameter</var>
-or information about <var>parameter</var> itself, depending on the value of
-<var>operator</var>. Each <var>operator</var> is a single letter:
+<dt><code class="code">${<var class="var">parameter</var>@<var class="var">operator</var>}</code></dt>
+<dd><p>The expansion is either a transformation of the value of <var class="var">parameter</var>
+or information about <var class="var">parameter</var> itself, depending on the value of
+<var class="var">operator</var>. Each <var class="var">operator</var> is a single letter:
</p>
-<dl compact="compact">
-<dt><span><code>U</code></span></dt>
-<dd><p>The expansion is a string that is the value of <var>parameter</var> with lowercase
+<dl class="table">
+<dt><code class="code">U</code></dt>
+<dd><p>The expansion is a string that is the value of <var class="var">parameter</var> with lowercase
alphabetic characters converted to uppercase.
</p></dd>
-<dt><span><code>u</code></span></dt>
-<dd><p>The expansion is a string that is the value of <var>parameter</var> with the first
+<dt><code class="code">u</code></dt>
+<dd><p>The expansion is a string that is the value of <var class="var">parameter</var> with the first
character converted to uppercase, if it is alphabetic.
</p></dd>
-<dt><span><code>L</code></span></dt>
-<dd><p>The expansion is a string that is the value of <var>parameter</var> with uppercase
+<dt><code class="code">L</code></dt>
+<dd><p>The expansion is a string that is the value of <var class="var">parameter</var> with uppercase
alphabetic characters converted to lowercase.
</p></dd>
-<dt><span><code>Q</code></span></dt>
-<dd><p>The expansion is a string that is the value of <var>parameter</var> quoted in a
+<dt><code class="code">Q</code></dt>
+<dd><p>The expansion is a string that is the value of <var class="var">parameter</var> quoted in a
format that can be reused as input.
</p></dd>
-<dt><span><code>E</code></span></dt>
-<dd><p>The expansion is a string that is the value of <var>parameter</var> with backslash
-escape sequences expanded as with the <code>$'…'</code> quoting mechanism.
+<dt><code class="code">E</code></dt>
+<dd><p>The expansion is a string that is the value of <var class="var">parameter</var> with backslash
+escape sequences expanded as with the <code class="code">$'…'</code> quoting mechanism.
</p></dd>
-<dt><span><code>P</code></span></dt>
+<dt><code class="code">P</code></dt>
<dd><p>The expansion is a string that is the result of expanding the value of
-<var>parameter</var> as if it were a prompt string (see <a href="#Controlling-the-Prompt">Controlling the Prompt</a>).
+<var class="var">parameter</var> as if it were a prompt string (see <a class="pxref" href="#Controlling-the-Prompt">Controlling the Prompt</a>).
</p></dd>
-<dt><span><code>A</code></span></dt>
+<dt><code class="code">A</code></dt>
<dd><p>The expansion is a string in the form of
-an assignment statement or <code>declare</code> command that, if
-evaluated, will recreate <var>parameter</var> with its attributes and value.
+an assignment statement or <code class="code">declare</code> command that, if
+evaluated, will recreate <var class="var">parameter</var> with its attributes and value.
</p></dd>
-<dt><span><code>K</code></span></dt>
-<dd><p>Produces a possibly-quoted version of the value of <var>parameter</var>,
+<dt><code class="code">K</code></dt>
+<dd><p>Produces a possibly-quoted version of the value of <var class="var">parameter</var>,
except that it prints the values of
indexed and associative arrays as a sequence of quoted key-value pairs
-(see <a href="#Arrays">Arrays</a>).
+(see <a class="pxref" href="#Arrays">Arrays</a>).
</p></dd>
-<dt><span><code>a</code></span></dt>
+<dt><code class="code">a</code></dt>
<dd><p>The expansion is a string consisting of flag values representing
-<var>parameter</var>’s attributes.
+<var class="var">parameter</var>’s attributes.
</p></dd>
-<dt><span><code>k</code></span></dt>
-<dd><p>Like the ‘<samp>K</samp>’ transformation, but expands the keys and values of
+<dt><code class="code">k</code></dt>
+<dd><p>Like the ‘<samp class="samp">K</samp>’ transformation, but expands the keys and values of
indexed and associative arrays to separate words after word splitting.
</p></dd>
</dl>
-<p>If <var>parameter</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+<p>If <var class="var">parameter</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the operation is applied to each positional
parameter in turn, and the expansion is the resultant list.
-If <var>parameter</var>
-is an array variable subscripted with ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">parameter</var>
+is an array variable subscripted with ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
the operation is applied to each member of the
array in turn, and the expansion is the resultant list.
</p>
<hr>
</div>
-<div class="subsection" id="Command-Substitution">
-<div class="header">
+<div class="subsection-level-extent" id="Command-Substitution">
+<div class="nav-panel">
<p>
Next: <a href="#Arithmetic-Expansion" accesskey="n" rel="next">Arithmetic Expansion</a>, Previous: <a href="#Shell-Parameter-Expansion" accesskey="p" rel="prev">Shell Parameter Expansion</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Command-Substitution-1"></span><h4 class="subsection">3.5.4 Command Substitution</h4>
-<span id="index-command-substitution"></span>
+<h4 class="subsection" id="Command-Substitution-1"><span>3.5.4 Command Substitution<a class="copiable-link" href="#Command-Substitution-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-command-substitution"></a>
<p>Command substitution allows the output of a command to replace
the command itself.
The standard form of command substitution occurs when a command is
enclosed as follows:
</p><div class="example">
-<pre class="example">$(<var>command</var>)
+<pre class="example-preformatted">$(<var class="var">command</var>)
</pre></div>
<p>or (deprecated)
</p><div class="example">
-<pre class="example">`<var>command</var>`.
+<pre class="example-preformatted">`<var class="var">command</var>`.
</pre></div>
-<p>Bash performs command substitution by executing <var>command</var> in a subshell
+<p>Bash performs command substitution by executing <var class="var">command</var> in a subshell
environment and replacing the command substitution with the standard
output of the command, with any trailing newlines deleted.
Embedded newlines are not deleted, but they may be removed during
word splitting.
-The command substitution <code>$(cat <var>file</var>)</code> can be
-replaced by the equivalent but faster <code>$(< <var>file</var>)</code>.
+The command substitution <code class="code">$(cat <var class="var">file</var>)</code> can be
+replaced by the equivalent but faster <code class="code">$(< <var class="var">file</var>)</code>.
</p>
<p>With the old-style backquote form of substitution,
backslash retains its literal meaning except when followed by
-‘<samp>$</samp>’, ‘<samp>`</samp>’, or ‘<samp>\</samp>’.
+‘<samp class="samp">$</samp>’, ‘<samp class="samp">`</samp>’, or ‘<samp class="samp">\</samp>’.
The first backquote not preceded by a backslash terminates the
command substitution.
-When using the <code>$(<var>command</var>)</code> form, all characters between
+When using the <code class="code">$(<var class="var">command</var>)</code> form, all characters between
the parentheses make up the command; none are treated specially.
</p>
<p>There is an alternate form of command substitution:
</p>
<div class="example">
-<pre class="example">${<var>c</var> <var>command</var>; }
+<pre class="example-preformatted">${<var class="var">c</var> <var class="var">command</var>; }
</pre></div>
-<p>which executes <var>command</var> in the current execution environment
+<p>which executes <var class="var">command</var> in the current execution environment
and captures its output, again with trailing newlines removed.
</p>
-<p>The character <var>c</var> following the open brace must be a space, tab,
-newline, or ‘<samp>|</samp>’, and the close brace must be in a position
+<p>The character <var class="var">c</var> following the open brace must be a space, tab,
+newline, or ‘<samp class="samp">|</samp>’, and the close brace must be in a position
where a reserved word may appear (i.e., preceded by a command terminator
such as semicolon).
Bash allows the close brace to be joined to the remaining characters in
the word without being followed by a shell metacharacter as a reserved
word would usually require.
</p>
-<p>Any side effects of <var>command</var> take effect immediately
+<p>Any side effects of <var class="var">command</var> take effect immediately
in the current execution environment and persist in the current
-environment after the command completes (e.g., the <code>exit</code> builtin
+environment after the command completes (e.g., the <code class="code">exit</code> builtin
will exit the shell).
</p>
<p>This type of command substitution superficially resembles executing an
unnamed shell function: local variables are created as when a shell
-function is executing, and the <code>return</code> builtin forces
-<var>command</var> to complete;
+function is executing, and the <code class="code">return</code> builtin forces
+<var class="var">command</var> to complete;
however, the rest of the execution environment,
including the positional parameters, is shared with the caller.
</p>
<p>If the first character following the open brace
-is a ‘<samp>|</samp>’, the construct expands to the
-value of the <code>REPLY</code> shell variable after <var>command</var> executes,
+is a ‘<samp class="samp">|</samp>’, the construct expands to the
+value of the <code class="code">REPLY</code> shell variable after <var class="var">command</var> executes,
without removing any trailing newlines,
-and the standard output of <var>command</var> remains the same as in the
+and the standard output of <var class="var">command</var> remains the same as in the
calling shell.
-Bash creates <code>REPLY</code> as an initially-unset local variable when
-<var>command</var> executes, and restores <code>REPLY</code> to the value it had
-before the command substitution after <var>command</var> completes,
+Bash creates <code class="code">REPLY</code> as an initially-unset local variable when
+<var class="var">command</var> executes, and restores <code class="code">REPLY</code> to the value it had
+before the command substitution after <var class="var">command</var> completes,
as with any local variable.
</p>
-<p>For example, this construct expands to ‘<samp>12345</samp>’, and leaves the
-shell variable <code>X</code> unchanged in the current execution environment:
+<p>For example, this construct expands to ‘<samp class="samp">12345</samp>’, and leaves the
+shell variable <code class="code">X</code> unchanged in the current execution environment:
</p>
<div class="example">
-<pre class="example">
+<pre class="example-preformatted">
${ local X=12345 ; echo $X; }
</pre></div>
-<p>(not declaring <code>X</code> as local would modify its value in the current
+<p>(not declaring <code class="code">X</code> as local would modify its value in the current
environment, as with normal shell function execution),
while this construct does not require any output to expand to
-‘<samp>12345</samp>’:
+‘<samp class="samp">12345</samp>’:
</p>
<div class="example">
-<pre class="example">${| REPLY=12345; }
+<pre class="example-preformatted">${| REPLY=12345; }
</pre></div>
-<p>and restores <code>REPLY</code> to the value it had before the command substitution.
+<p>and restores <code class="code">REPLY</code> to the value it had before the command substitution.
</p>
<p>Command substitutions may be nested. To nest when using the backquoted
form, escape the inner backquotes with backslashes.
</p>
<hr>
</div>
-<div class="subsection" id="Arithmetic-Expansion">
-<div class="header">
+<div class="subsection-level-extent" id="Arithmetic-Expansion">
+<div class="nav-panel">
<p>
Next: <a href="#Process-Substitution" accesskey="n" rel="next">Process Substitution</a>, Previous: <a href="#Command-Substitution" accesskey="p" rel="prev">Command Substitution</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Arithmetic-Expansion-1"></span><h4 class="subsection">3.5.5 Arithmetic Expansion</h4>
-<span id="index-expansion_002c-arithmetic"></span>
-<span id="index-arithmetic-expansion"></span>
+<h4 class="subsection" id="Arithmetic-Expansion-1"><span>3.5.5 Arithmetic Expansion<a class="copiable-link" href="#Arithmetic-Expansion-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-expansion_002c-arithmetic"></a>
+<a class="index-entry-id" id="index-arithmetic-expansion"></a>
<p>Arithmetic expansion allows the evaluation of an arithmetic expression
and the substitution of the result. The format for arithmetic expansion is:
</p>
<div class="example">
-<pre class="example">$(( <var>expression</var> ))
+<pre class="example-preformatted">$(( <var class="var">expression</var> ))
</pre></div>
-<p>The <var>expression</var> undergoes the same expansions
+<p>The <var class="var">expression</var> undergoes the same expansions
as if it were within double quotes,
-but double quote characters in <var>expression</var> are not treated specially
+but double quote characters in <var class="var">expression</var> are not treated specially
and are removed.
All tokens in the expression undergo parameter and variable expansion,
command substitution, and quote removal.
Arithmetic expansions may be nested.
</p>
<p>The evaluation is performed according to the rules listed below
-(see <a href="#Shell-Arithmetic">Shell Arithmetic</a>).
+(see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>).
If the expression is invalid, Bash prints a message indicating
failure to the standard error and no substitution occurs.
</p>
<hr>
</div>
-<div class="subsection" id="Process-Substitution">
-<div class="header">
+<div class="subsection-level-extent" id="Process-Substitution">
+<div class="nav-panel">
<p>
Next: <a href="#Word-Splitting" accesskey="n" rel="next">Word Splitting</a>, Previous: <a href="#Arithmetic-Expansion" accesskey="p" rel="prev">Arithmetic Expansion</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Process-Substitution-1"></span><h4 class="subsection">3.5.6 Process Substitution</h4>
-<span id="index-process-substitution"></span>
+<h4 class="subsection" id="Process-Substitution-1"><span>3.5.6 Process Substitution<a class="copiable-link" href="#Process-Substitution-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-process-substitution"></a>
<p>Process substitution allows a process’s input or output to be
referred to using a filename.
It takes the form of
</p><div class="example">
-<pre class="example"><(<var>list</var>)
+<pre class="example-preformatted"><(<var class="var">list</var>)
</pre></div>
<p>or
</p><div class="example">
-<pre class="example">>(<var>list</var>)
+<pre class="example-preformatted">>(<var class="var">list</var>)
</pre></div>
-<p>The process <var>list</var> is run asynchronously, and its input or output
+<p>The process <var class="var">list</var> is run asynchronously, and its input or output
appears as a filename.
This filename is
passed as an argument to the current command as the result of the
expansion.
-If the <code>>(<var>list</var>)</code> form is used, writing to
-the file will provide input for <var>list</var>. If the
-<code><(<var>list</var>)</code> form is used, the file passed as an
-argument should be read to obtain the output of <var>list</var>.
-Note that no space may appear between the <code><</code> or <code>></code>
+If the <code class="code">>(<var class="var">list</var>)</code> form is used, writing to
+the file will provide input for <var class="var">list</var>. If the
+<code class="code"><(<var class="var">list</var>)</code> form is used, the file passed as an
+argument should be read to obtain the output of <var class="var">list</var>.
+Note that no space may appear between the <code class="code"><</code> or <code class="code">></code>
and the left parenthesis, otherwise the construct would be interpreted
as a redirection.
Process substitution is supported on systems that support named
-pipes (<small>FIFO</small>s) or the <samp>/dev/fd</samp> method of naming open files.
+pipes (<small class="sc">FIFO</small>s) or the <samp class="file">/dev/fd</samp> method of naming open files.
</p>
<p>When available, process substitution is performed simultaneously with
parameter and variable expansion, command substitution, and arithmetic
</p>
<hr>
</div>
-<div class="subsection" id="Word-Splitting">
-<div class="header">
+<div class="subsection-level-extent" id="Word-Splitting">
+<div class="nav-panel">
<p>
Next: <a href="#Filename-Expansion" accesskey="n" rel="next">Filename Expansion</a>, Previous: <a href="#Process-Substitution" accesskey="p" rel="prev">Process Substitution</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Word-Splitting-1"></span><h4 class="subsection">3.5.7 Word Splitting</h4>
-<span id="index-word-splitting"></span>
+<h4 class="subsection" id="Word-Splitting-1"><span>3.5.7 Word Splitting<a class="copiable-link" href="#Word-Splitting-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-word-splitting"></a>
<p>The shell scans the results of parameter expansion, command substitution,
and arithmetic expansion that did not occur within double quotes for
word splitting.
</p>
-<p>The shell treats each character of <code>$IFS</code> as a delimiter, and splits
+<p>The shell treats each character of <code class="env">$IFS</code> as a delimiter, and splits
the results of the other expansions into words using these characters
as field terminators.
</p>
-<p>If <code>IFS</code> is unset, or its value is exactly <code><space><tab><newline></code>,
+<p>If <code class="env">IFS</code> is unset, or its value is exactly <code class="code"><space><tab><newline></code>,
the default, then sequences of
-<code>space</code>, <code>tab</code>, and <code>newline</code>
+<code class="code">space</code>, <code class="code">tab</code>, and <code class="code">newline</code>
at the beginning and end of the results of the previous
-expansions are ignored, and any sequence of <code>IFS</code>
+expansions are ignored, and any sequence of <code class="env">IFS</code>
characters not at the beginning or end serves to delimit words.
-If <code>IFS</code> has a value other than the default, then sequences of
-the whitespace characters <code>space</code>, <code>tab</code>, and <code>newline</code>
+If <code class="env">IFS</code> has a value other than the default, then sequences of
+the whitespace characters <code class="code">space</code>, <code class="code">tab</code>, and <code class="code">newline</code>
are ignored at the beginning and end of the
word, as long as the whitespace character is in the
-value of <code>IFS</code> (an <code>IFS</code> whitespace character).
-Any character in <code>IFS</code> that is not <code>IFS</code>
-whitespace, along with any adjacent <code>IFS</code>
-whitespace characters, delimits a field. A sequence of <code>IFS</code>
+value of <code class="env">IFS</code> (an <code class="env">IFS</code> whitespace character).
+Any character in <code class="env">IFS</code> that is not <code class="env">IFS</code>
+whitespace, along with any adjacent <code class="env">IFS</code>
+whitespace characters, delimits a field. A sequence of <code class="env">IFS</code>
whitespace characters is also treated as a delimiter.
</p>
-<p>If the value of <code>IFS</code> is null, no word splitting occurs.
-If <code>IFS</code> is unset, word splitting behaves as if it contained
-the default value <code><space><tab><newline></code>.
+<p>If the value of <code class="env">IFS</code> is null, no word splitting occurs.
+If <code class="env">IFS</code> is unset, word splitting behaves as if it contained
+the default value <code class="code"><space><tab><newline></code>.
</p>
-<p>Explicit null arguments (<code>""</code> or <code>''</code>) are retained
+<p>Explicit null arguments (<code class="code">""</code> or <code class="code">''</code>) are retained
and passed to commands as empty strings.
Unquoted implicit null arguments, resulting from the expansion of
parameters that have no values, are removed.
When a quoted null argument appears as part of a word whose expansion is
non-null, the null argument is removed.
That is, the word
-<code>-d''</code> becomes <code>-d</code> after word splitting and
+<code class="code">-d''</code> becomes <code class="code">-d</code> after word splitting and
null argument removal.
</p>
<p>Note that if no expansion occurs, no splitting
</p>
<hr>
</div>
-<div class="subsection" id="Filename-Expansion">
-<div class="header">
+<div class="subsection-level-extent" id="Filename-Expansion">
+<div class="nav-panel">
<p>
Next: <a href="#Quote-Removal" accesskey="n" rel="next">Quote Removal</a>, Previous: <a href="#Word-Splitting" accesskey="p" rel="prev">Word Splitting</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Filename-Expansion-1"></span><h4 class="subsection">3.5.8 Filename Expansion</h4>
-<span id="index-expansion_002c-filename"></span>
-<span id="index-expansion_002c-pathname"></span>
-<span id="index-filename-expansion"></span>
-<span id="index-pathname-expansion"></span>
+<h4 class="subsection" id="Filename-Expansion-1"><span>3.5.8 Filename Expansion<a class="copiable-link" href="#Filename-Expansion-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-expansion_002c-filename"></a>
+<a class="index-entry-id" id="index-expansion_002c-pathname"></a>
+<a class="index-entry-id" id="index-filename-expansion"></a>
+<a class="index-entry-id" id="index-pathname-expansion"></a>
-<p>After word splitting, unless the <samp>-f</samp> option has been set
-(see <a href="#The-Set-Builtin">The Set Builtin</a>), Bash scans each word for the characters
-‘<samp>*</samp>’, ‘<samp>?</samp>’, and ‘<samp>[</samp>’.
+<p>After word splitting, unless the <samp class="option">-f</samp> option has been set
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>), Bash scans each word for the characters
+‘<samp class="samp">*</samp>’, ‘<samp class="samp">?</samp>’, and ‘<samp class="samp">[</samp>’.
If one of these characters appears, and is not quoted, then the word is
-regarded as a <var>pattern</var>,
+regarded as a <var class="var">pattern</var>,
and replaced with an alphabetically sorted list of
-filenames matching the pattern (see <a href="#Pattern-Matching">Pattern Matching</a>).
+filenames matching the pattern (see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>).
If no matching filenames are found,
-and the shell option <code>nullglob</code> is disabled, the word is left
+and the shell option <code class="code">nullglob</code> is disabled, the word is left
unchanged.
-If the <code>nullglob</code> option is set, and no matches are found, the word
+If the <code class="code">nullglob</code> option is set, and no matches are found, the word
is removed.
-If the <code>failglob</code> shell option is set, and no matches are found,
+If the <code class="code">failglob</code> shell option is set, and no matches are found,
an error message is printed and the command is not executed.
-If the shell option <code>nocaseglob</code> is enabled, the match is performed
+If the shell option <code class="code">nocaseglob</code> is enabled, the match is performed
without regard to the case of alphabetic characters.
</p>
-<p>When a pattern is used for filename expansion, the character ‘<samp>.</samp>’
+<p>When a pattern is used for filename expansion, the character ‘<samp class="samp">.</samp>’
at the start of a filename or immediately following a slash
-must be matched explicitly, unless the shell option <code>dotglob</code> is set.
-In order to match the filenames ‘<samp>.</samp>’ and ‘<samp>..</samp>’,
-the pattern must begin with ‘<samp>.</samp>’ (for example, ‘<samp>.?</samp>’),
-even if <code>dotglob</code> is set.
-If the <code>globskipdots</code> shell option is enabled, the filenames
-‘<samp>.</samp>’ and ‘<samp>..</samp>’ are never matched, even if the pattern begins
-with a ‘<samp>.</samp>’.
-When not matching filenames, the ‘<samp>.</samp>’ character is not treated specially.
+must be matched explicitly, unless the shell option <code class="code">dotglob</code> is set.
+In order to match the filenames ‘<samp class="samp">.</samp>’ and ‘<samp class="samp">..</samp>’,
+the pattern must begin with ‘<samp class="samp">.</samp>’ (for example, ‘<samp class="samp">.?</samp>’),
+even if <code class="code">dotglob</code> is set.
+If the <code class="code">globskipdots</code> shell option is enabled, the filenames
+‘<samp class="samp">.</samp>’ and ‘<samp class="samp">..</samp>’ never match, even if the pattern begins
+with a ‘<samp class="samp">.</samp>’.
+When not matching filenames, the ‘<samp class="samp">.</samp>’ character is not treated specially.
</p>
<p>When matching a filename, the slash character must always be
matched explicitly by a slash in the pattern, but in other matching
contexts it can be matched by a special pattern character as described
-below (see <a href="#Pattern-Matching">Pattern Matching</a>).
+below (see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>).
</p>
-<p>See the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>,
-for a description of the <code>nocaseglob</code>, <code>nullglob</code>,
-<code>globskipdots</code>,
-<code>failglob</code>, and <code>dotglob</code> options.
+<p>See the description of <code class="code">shopt</code> in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>,
+for a description of the <code class="code">nocaseglob</code>, <code class="code">nullglob</code>,
+<code class="code">globskipdots</code>,
+<code class="code">failglob</code>, and <code class="code">dotglob</code> options.
</p>
-<p>The <code>GLOBIGNORE</code>
+<p>The <code class="env">GLOBIGNORE</code>
shell variable may be used to restrict the set of file names matching a
-pattern. If <code>GLOBIGNORE</code>
+pattern. If <code class="env">GLOBIGNORE</code>
is set, each matching file name that also matches one of the patterns in
-<code>GLOBIGNORE</code> is removed from the list of matches.
-If the <code>nocaseglob</code> option is set, the matching against the patterns in
-<code>GLOBIGNORE</code> is performed without regard to case.
+<code class="env">GLOBIGNORE</code> is removed from the list of matches.
+If the <code class="code">nocaseglob</code> option is set, the matching against the patterns in
+<code class="env">GLOBIGNORE</code> is performed without regard to case.
The filenames
-<samp>.</samp> and <samp>..</samp>
-are always ignored when <code>GLOBIGNORE</code>
+<samp class="file">.</samp> and <samp class="file">..</samp>
+are always ignored when <code class="env">GLOBIGNORE</code>
is set and not null.
-However, setting <code>GLOBIGNORE</code> to a non-null value has the effect of
-enabling the <code>dotglob</code>
+However, setting <code class="env">GLOBIGNORE</code> to a non-null value has the effect of
+enabling the <code class="code">dotglob</code>
shell option, so all other filenames beginning with a
-‘<samp>.</samp>’ will match.
+‘<samp class="samp">.</samp>’ will match.
To get the old behavior of ignoring filenames beginning with a
-‘<samp>.</samp>’, make ‘<samp>.*</samp>’ one of the patterns in <code>GLOBIGNORE</code>.
-The <code>dotglob</code> option is disabled when <code>GLOBIGNORE</code>
+‘<samp class="samp">.</samp>’, make ‘<samp class="samp">.*</samp>’ one of the patterns in <code class="env">GLOBIGNORE</code>.
+The <code class="code">dotglob</code> option is disabled when <code class="env">GLOBIGNORE</code>
is unset.
</p>
<p>After the pattern is expanded and matched against filenames, the value of the
-<code>GLOBSORT</code> variable controls how the results are sorted, as described
-below (see <a href="#Bash-Variables">Bash Variables</a>).
+<code class="env">GLOBSORT</code> variable controls how the results are sorted, as described
+below (see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Pattern-Matching" accesskey="1">Pattern Matching</a></li>
</ul>
<hr>
-<div class="subsubsection" id="Pattern-Matching">
-<div class="header">
+<div class="subsubsection-level-extent" id="Pattern-Matching">
+<div class="nav-panel">
<p>
Up: <a href="#Filename-Expansion" accesskey="u" rel="up">Filename Expansion</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Pattern-Matching-1"></span><h4 class="subsubsection">3.5.8.1 Pattern Matching</h4>
-<span id="index-pattern-matching"></span>
-<span id="index-matching_002c-pattern"></span>
+<h4 class="subsubsection" id="Pattern-Matching-1"><span>3.5.8.1 Pattern Matching<a class="copiable-link" href="#Pattern-Matching-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-pattern-matching"></a>
+<a class="index-entry-id" id="index-matching_002c-pattern"></a>
<p>Any character that appears in a pattern, other than the special pattern
characters described below, matches itself.
-The <small>NUL</small> character may not occur in a pattern.
+The <small class="sc">NUL</small> character may not occur in a pattern.
A backslash escapes the following character; the
escaping backslash is discarded when matching.
The special pattern characters must be quoted if they are to be matched
literally.
</p>
<p>The special pattern characters have the following meanings:
-</p><dl compact="compact">
-<dt><span><code>*</code></span></dt>
+</p><dl class="table">
+<dt><code class="code">*</code></dt>
<dd><p>Matches any string, including the null string.
-When the <code>globstar</code> shell option is enabled, and ‘<samp>*</samp>’ is used in
-a filename expansion context, two adjacent ‘<samp>*</samp>’s used as a single
+When the <code class="code">globstar</code> shell option is enabled, and ‘<samp class="samp">*</samp>’ is used in
+a filename expansion context, two adjacent ‘<samp class="samp">*</samp>’s used as a single
pattern will match all files and zero or more directories and
subdirectories.
-If followed by a ‘<samp>/</samp>’, two adjacent ‘<samp>*</samp>’s will match only
+If followed by a ‘<samp class="samp">/</samp>’, two adjacent ‘<samp class="samp">*</samp>’s will match only
directories and subdirectories.
</p></dd>
-<dt><span><code>?</code></span></dt>
+<dt><code class="code">?</code></dt>
<dd><p>Matches any single character.
</p></dd>
-<dt><span><code>[…]</code></span></dt>
-<dd><p>Matches any one of the enclosed characters. A pair of characters
-separated by a hyphen denotes a <var>range expression</var>;
+<dt><code class="code">[…]</code></dt>
+<dd><p>Matches any one of the enclosed characters.
+A pair of characters separated by a hyphen denotes a <var class="var">range expression</var>;
any character that falls between those two characters, inclusive,
using the current locale’s collating sequence and character set,
is matched. If the first character following the
-‘<samp>[</samp>’ is a ‘<samp>!</samp>’ or a ‘<samp>^</samp>’
-then any character not enclosed is matched. A ‘<samp>-</samp>’
+‘<samp class="samp">[</samp>’ is a ‘<samp class="samp">!</samp>’ or a ‘<samp class="samp">^</samp>’
+then any character not enclosed is matched. A ‘<samp class="samp">−</samp>’
may be matched by including it as the first or last character
-in the set. A ‘<samp>]</samp>’ may be matched by including it as the first
+in the set. A ‘<samp class="samp">]</samp>’ may be matched by including it as the first
character in the set.
The sorting order of characters in range expressions,
and the characters included in the range,
are determined by
the current locale and the values of the
-<code>LC_COLLATE</code> and <code>LC_ALL</code> shell variables, if set.
+<code class="env">LC_COLLATE</code> and <code class="env">LC_ALL</code> shell variables, if set.
</p>
-<p>For example, in the default C locale, ‘<samp>[a-dx-z]</samp>’ is equivalent to
-‘<samp>[abcdxyz]</samp>’. Many locales sort characters in dictionary order, and in
-these locales ‘<samp>[a-dx-z]</samp>’ is typically not equivalent to ‘<samp>[abcdxyz]</samp>’;
-it might be equivalent to ‘<samp>[aBbCcDdxYyZz]</samp>’, for example. To obtain
+<p>For example, in the default C locale, ‘<samp class="samp">[a-dx-z]</samp>’ is equivalent to
+‘<samp class="samp">[abcdxyz]</samp>’. Many locales sort characters in dictionary order, and in
+these locales ‘<samp class="samp">[a-dx-z]</samp>’ is typically not equivalent to ‘<samp class="samp">[abcdxyz]</samp>’;
+it might be equivalent to ‘<samp class="samp">[aBbCcDdxYyZz]</samp>’, for example. To obtain
the traditional interpretation of ranges in bracket expressions, you can
-force the use of the C locale by setting the <code>LC_COLLATE</code> or
-<code>LC_ALL</code> environment variable to the value ‘<samp>C</samp>’, or enable the
-<code>globasciiranges</code> shell option.
+force the use of the C locale by setting the <code class="env">LC_COLLATE</code> or
+<code class="env">LC_ALL</code> environment variable to the value ‘<samp class="samp">C</samp>’, or enable the
+<code class="code">globasciiranges</code> shell option.
</p>
-<p>Within ‘<samp>[</samp>’ and ‘<samp>]</samp>’, <em>character classes</em> can be specified
+<p>Within ‘<samp class="samp">[</samp>’ and ‘<samp class="samp">]</samp>’, <em class="dfn">character classes</em> can be specified
using the syntax
-<code>[:</code><var>class</var><code>:]</code>, where <var>class</var> is one of the
-following classes defined in the <small>POSIX</small> standard:
+<code class="code">[:</code><var class="var">class</var><code class="code">:]</code>, where <var class="var">class</var> is one of the
+following classes defined in the <small class="sc">POSIX</small> standard:
</p><div class="example">
-<pre class="example">alnum alpha ascii blank cntrl digit graph lower
+<pre class="example-preformatted">alnum alpha ascii blank cntrl digit graph lower
print punct space upper word xdigit
</pre></div>
<p>A character class matches any character belonging to that class.
-The <code>word</code> character class matches letters, digits, and the character
-‘<samp>_</samp>’.
+The <code class="code">word</code> character class matches letters, digits, and the character
+‘<samp class="samp">_</samp>’.
</p>
-<p>Within ‘<samp>[</samp>’ and ‘<samp>]</samp>’, an <em>equivalence class</em> can be
-specified using the syntax <code>[=</code><var>c</var><code>=]</code>, which
+<p>Within ‘<samp class="samp">[</samp>’ and ‘<samp class="samp">]</samp>’, an <em class="dfn">equivalence class</em> can be
+specified using the syntax <code class="code">[=</code><var class="var">c</var><code class="code">=]</code>, which
matches all characters with the same collation weight (as defined
-by the current locale) as the character <var>c</var>.
+by the current locale) as the character <var class="var">c</var>.
</p>
-<p>Within ‘<samp>[</samp>’ and ‘<samp>]</samp>’, the syntax <code>[.</code><var>symbol</var><code>.]</code>
-matches the collating symbol <var>symbol</var>.
+<p>Within ‘<samp class="samp">[</samp>’ and ‘<samp class="samp">]</samp>’, the syntax <code class="code">[.</code><var class="var">symbol</var><code class="code">.]</code>
+matches the collating symbol <var class="var">symbol</var>.
</p></dd>
</dl>
-<p>If the <code>extglob</code> shell option is enabled using the <code>shopt</code>
+<p>If the <code class="code">extglob</code> shell option is enabled using the <code class="code">shopt</code>
builtin, the shell recognizes several extended pattern matching operators.
-In the following description, a <var>pattern-list</var> is a list of one
-or more patterns separated by a ‘<samp>|</samp>’.
-When matching filenames, the <code>dotglob</code> shell option determines
+In the following description, a <var class="var">pattern-list</var> is a list of one
+or more patterns separated by a ‘<samp class="samp">|</samp>’.
+When matching filenames, the <code class="code">dotglob</code> shell option determines
the set of filenames that are tested, as described above.
Composite patterns may be formed using one or more of the following
sub-patterns:
</p>
-<dl compact="compact">
-<dt><span><code>?(<var>pattern-list</var>)</code></span></dt>
+<dl class="table">
+<dt><code class="code">?(<var class="var">pattern-list</var>)</code></dt>
<dd><p>Matches zero or one occurrence of the given patterns.
</p>
</dd>
-<dt><span><code>*(<var>pattern-list</var>)</code></span></dt>
+<dt><code class="code">*(<var class="var">pattern-list</var>)</code></dt>
<dd><p>Matches zero or more occurrences of the given patterns.
</p>
</dd>
-<dt><span><code>+(<var>pattern-list</var>)</code></span></dt>
+<dt><code class="code">+(<var class="var">pattern-list</var>)</code></dt>
<dd><p>Matches one or more occurrences of the given patterns.
</p>
</dd>
-<dt><span><code>@(<var>pattern-list</var>)</code></span></dt>
+<dt><code class="code">@(<var class="var">pattern-list</var>)</code></dt>
<dd><p>Matches one of the given patterns.
</p>
</dd>
-<dt><span><code>!(<var>pattern-list</var>)</code></span></dt>
+<dt><code class="code">!(<var class="var">pattern-list</var>)</code></dt>
<dd><p>Matches anything except one of the given patterns.
</p></dd>
</dl>
-<p>The <code>extglob</code> option changes the behavior of the parser, since the
+<p>The <code class="code">extglob</code> option changes the behavior of the parser, since the
parentheses are normally treated as operators with syntactic meaning.
To ensure that extended matching patterns are parsed correctly, make sure
-that <code>extglob</code> is enabled before parsing constructs containing the
+that <code class="code">extglob</code> is enabled before parsing constructs containing the
patterns, including shell functions and command substitutions.
</p>
-<p>When matching filenames, the <code>dotglob</code> shell option determines
+<p>When matching filenames, the <code class="code">dotglob</code> shell option determines
the set of filenames that are tested:
-when <code>dotglob</code> is enabled, the set of filenames includes all files
-beginning with ‘<samp>.</samp>’, but the filenames
-‘<samp>.</samp>’ and ‘<samp>..</samp>’ must be matched by a
+when <code class="code">dotglob</code> is enabled, the set of filenames includes all files
+beginning with ‘<samp class="samp">.</samp>’, but the filenames
+‘<samp class="samp">.</samp>’ and ‘<samp class="samp">..</samp>’ must be matched by a
pattern or sub-pattern that begins with a dot;
when it is disabled, the set does not
include any filenames beginning with “.” unless the pattern
-or sub-pattern begins with a ‘<samp>.</samp>’.
-As above, ‘<samp>.</samp>’ only has a special meaning when matching filenames.
+or sub-pattern begins with a ‘<samp class="samp">.</samp>’.
+As above, ‘<samp class="samp">.</samp>’ only has a special meaning when matching filenames.
</p>
<p>Complicated extended pattern matching against long strings is slow,
especially when the patterns contain alternations and the strings
<hr>
</div>
</div>
-<div class="subsection" id="Quote-Removal">
-<div class="header">
+<div class="subsection-level-extent" id="Quote-Removal">
+<div class="nav-panel">
<p>
Previous: <a href="#Filename-Expansion" accesskey="p" rel="prev">Filename Expansion</a>, Up: <a href="#Shell-Expansions" accesskey="u" rel="up">Shell Expansions</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Quote-Removal-1"></span><h4 class="subsection">3.5.9 Quote Removal</h4>
+<h4 class="subsection" id="Quote-Removal-1"><span>3.5.9 Quote Removal<a class="copiable-link" href="#Quote-Removal-1"> ¶</a></span></h4>
<p>After the preceding expansions, all unquoted occurrences of the
-characters ‘<samp>\</samp>’, ‘<samp>'</samp>’, and ‘<samp>"</samp>’ that did not
+characters ‘<samp class="samp">\</samp>’, ‘<samp class="samp">'</samp>’, and ‘<samp class="samp">"</samp>’ that did not
result from one of the above expansions are removed.
</p>
<hr>
</div>
</div>
-<div class="section" id="Redirections">
-<div class="header">
+<div class="section-level-extent" id="Redirections">
+<div class="nav-panel">
<p>
Next: <a href="#Executing-Commands" accesskey="n" rel="next">Executing Commands</a>, Previous: <a href="#Shell-Expansions" accesskey="p" rel="prev">Shell Expansions</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Redirections-1"></span><h3 class="section">3.6 Redirections</h3>
-<span id="index-redirection"></span>
+<h3 class="section" id="Redirections-1"><span>3.6 Redirections<a class="copiable-link" href="#Redirections-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-redirection"></a>
<p>Before a command is executed, its input and output
-may be <em>redirected</em>
+may be <em class="dfn">redirected</em>
using a special notation interpreted by the shell.
-<em>Redirection</em> allows commands’ file handles to be
+<em class="dfn">Redirection</em> allows commands’ file handles to be
duplicated, opened, closed,
made to refer to different files,
and can change the files the command reads from and writes to.
left to right.
</p>
<p>Each redirection that may be preceded by a file descriptor number
-may instead be preceded by a word of the form {<var>varname</var>}.
+may instead be preceded by a word of the form {<var class="var">varname</var>}.
In this case, for each redirection operator except
>&- and <&-, the shell will allocate a file descriptor greater
-than 10 and assign it to {<var>varname</var>}. If >&- or <&- is preceded
-by {<var>varname</var>}, the value of <var>varname</var> defines the file
+than 10 and assign it to {<var class="var">varname</var>}. If >&- or <&- is preceded
+by {<var class="var">varname</var>}, the value of <var class="var">varname</var> defines the file
descriptor to close.
-If {<var>varname</var>} is supplied, the redirection persists beyond
+If {<var class="var">varname</var>} is supplied, the redirection persists beyond
the scope of the command, allowing the shell programmer to manage
the file descriptor’s lifetime manually.
-The <code>varredir_close</code> shell option manages this behavior
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+The <code class="code">varredir_close</code> shell option manages this behavior
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
</p>
<p>In the following descriptions, if the file descriptor number is
omitted, and the first character of the redirection operator is
-‘<samp><</samp>’, the redirection refers to the standard input (file
+‘<samp class="samp"><</samp>’, the redirection refers to the standard input (file
descriptor 0). If the first character of the redirection operator
-is ‘<samp>></samp>’, the redirection refers to the standard output (file
+is ‘<samp class="samp">></samp>’, the redirection refers to the standard output (file
descriptor 1).
</p>
<p>The word following the redirection operator in the following
<p>Note that the order of redirections is significant. For example,
the command
</p><div class="example">
-<pre class="example">ls > <var>dirlist</var> 2>&1
+<pre class="example-preformatted">ls > <var class="var">dirlist</var> 2>&1
</pre></div>
<p>directs both standard output (file descriptor 1) and standard error
-(file descriptor 2) to the file <var>dirlist</var>, while the command
+(file descriptor 2) to the file <var class="var">dirlist</var>, while the command
</p><div class="example">
-<pre class="example">ls 2>&1 > <var>dirlist</var>
+<pre class="example-preformatted">ls 2>&1 > <var class="var">dirlist</var>
</pre></div>
-<p>directs only the standard output to file <var>dirlist</var>,
+<p>directs only the standard output to file <var class="var">dirlist</var>,
because the standard error was made a copy of the standard output
-before the standard output was redirected to <var>dirlist</var>.
+before the standard output was redirected to <var class="var">dirlist</var>.
</p>
<p>Bash handles several filenames specially when they are used in
redirections, as described in the following table.
special files, Bash will use them; otherwise it will emulate them
internally with the behavior described below.
</p>
-<dl compact="compact">
-<dt><span><code>/dev/fd/<var>fd</var></code></span></dt>
-<dd><p>If <var>fd</var> is a valid integer, file descriptor <var>fd</var> is duplicated.
+<dl class="table">
+<dt><code class="code">/dev/fd/<var class="var">fd</var></code></dt>
+<dd><p>If <var class="var">fd</var> is a valid integer, file descriptor <var class="var">fd</var> is duplicated.
</p>
</dd>
-<dt><span><code>/dev/stdin</code></span></dt>
+<dt><code class="code">/dev/stdin</code></dt>
<dd><p>File descriptor 0 is duplicated.
</p>
</dd>
-<dt><span><code>/dev/stdout</code></span></dt>
+<dt><code class="code">/dev/stdout</code></dt>
<dd><p>File descriptor 1 is duplicated.
</p>
</dd>
-<dt><span><code>/dev/stderr</code></span></dt>
+<dt><code class="code">/dev/stderr</code></dt>
<dd><p>File descriptor 2 is duplicated.
</p>
</dd>
-<dt><span><code>/dev/tcp/<var>host</var>/<var>port</var></code></span></dt>
-<dd><p>If <var>host</var> is a valid hostname or Internet address, and <var>port</var>
+<dt><code class="code">/dev/tcp/<var class="var">host</var>/<var class="var">port</var></code></dt>
+<dd><p>If <var class="var">host</var> is a valid hostname or Internet address, and <var class="var">port</var>
is an integer port number or service name, Bash attempts to open
the corresponding TCP socket.
</p>
</dd>
-<dt><span><code>/dev/udp/<var>host</var>/<var>port</var></code></span></dt>
-<dd><p>If <var>host</var> is a valid hostname or Internet address, and <var>port</var>
+<dt><code class="code">/dev/udp/<var class="var">host</var>/<var class="var">port</var></code></dt>
+<dd><p>If <var class="var">host</var> is a valid hostname or Internet address, and <var class="var">port</var>
is an integer port number or service name, Bash attempts to open
the corresponding UDP socket.
</p></dd>
care, as they may conflict with file descriptors the shell uses
internally.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Redirecting-Input" accesskey="1">Redirecting Input</a></li>
<li><a href="#Redirecting-Output" accesskey="2">Redirecting Output</a></li>
<li><a href="#Appending-Redirected-Output" accesskey="3">Appending Redirected Output</a></li>
<li><a href="#Moving-File-Descriptors" accesskey="9">Moving File Descriptors</a></li>
<li><a href="#Opening-File-Descriptors-for-Reading-and-Writing">Opening File Descriptors for Reading and Writing</a></li>
</ul>
-<div class="subsection" id="Redirecting-Input">
-<h4 class="subsection">3.6.1 Redirecting Input</h4>
+<div class="subsection-level-extent" id="Redirecting-Input">
+<h4 class="subsection"><span>3.6.1 Redirecting Input<a class="copiable-link" href="#Redirecting-Input"> ¶</a></span></h4>
<p>Redirection of input causes the file whose name results from
-the expansion of <var>word</var>
-to be opened for reading on file descriptor <code>n</code>,
-or the standard input (file descriptor 0) if <code>n</code>
+the expansion of <var class="var">word</var>
+to be opened for reading on file descriptor <code class="code">n</code>,
+or the standard input (file descriptor 0) if <code class="code">n</code>
is not specified.
</p>
<p>The general format for redirecting input is:
</p><div class="example">
-<pre class="example">[<var>n</var>]<<var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]<<var class="var">word</var>
</pre></div>
</div>
-<div class="subsection" id="Redirecting-Output">
-<h4 class="subsection">3.6.2 Redirecting Output</h4>
+<div class="subsection-level-extent" id="Redirecting-Output">
+<h4 class="subsection"><span>3.6.2 Redirecting Output<a class="copiable-link" href="#Redirecting-Output"> ¶</a></span></h4>
<p>Redirection of output causes the file whose name results from
-the expansion of <var>word</var>
-to be opened for writing on file descriptor <var>n</var>,
-or the standard output (file descriptor 1) if <var>n</var>
+the expansion of <var class="var">word</var>
+to be opened for writing on file descriptor <var class="var">n</var>,
+or the standard output (file descriptor 1) if <var class="var">n</var>
is not specified. If the file does not exist it is created;
if it does exist it is truncated to zero size.
</p>
<p>The general format for redirecting output is:
</p><div class="example">
-<pre class="example">[<var>n</var>]>[|]<var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]>[|]<var class="var">word</var>
</pre></div>
-<p>If the redirection operator is ‘<samp>></samp>’, and the <code>noclobber</code>
-option to the <code>set</code> builtin has been enabled, the redirection
+<p>If the redirection operator is ‘<samp class="samp">></samp>’, and the <code class="code">noclobber</code>
+option to the <code class="code">set</code> builtin has been enabled, the redirection
will fail if the file whose name results from the expansion of
-<var>word</var> exists and is a regular file.
-If the redirection operator is ‘<samp>>|</samp>’, or the redirection operator is
-‘<samp>></samp>’ and the <code>noclobber</code> option is not enabled, the redirection
-is attempted even if the file named by <var>word</var> exists.
+<var class="var">word</var> exists and is a regular file.
+If the redirection operator is ‘<samp class="samp">>|</samp>’, or the redirection operator is
+‘<samp class="samp">></samp>’ and the <code class="code">noclobber</code> option is not enabled, the redirection
+is attempted even if the file named by <var class="var">word</var> exists.
</p>
</div>
-<div class="subsection" id="Appending-Redirected-Output">
-<h4 class="subsection">3.6.3 Appending Redirected Output</h4>
+<div class="subsection-level-extent" id="Appending-Redirected-Output">
+<h4 class="subsection"><span>3.6.3 Appending Redirected Output<a class="copiable-link" href="#Appending-Redirected-Output"> ¶</a></span></h4>
<p>Redirection of output in this fashion
causes the file whose name results from
-the expansion of <var>word</var>
-to be opened for appending on file descriptor <var>n</var>,
-or the standard output (file descriptor 1) if <var>n</var>
+the expansion of <var class="var">word</var>
+to be opened for appending on file descriptor <var class="var">n</var>,
+or the standard output (file descriptor 1) if <var class="var">n</var>
is not specified. If the file does not exist it is created.
</p>
<p>The general format for appending output is:
</p><div class="example">
-<pre class="example">[<var>n</var>]>><var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]>><var class="var">word</var>
</pre></div>
</div>
-<div class="subsection" id="Redirecting-Standard-Output-and-Standard-Error">
-<h4 class="subsection">3.6.4 Redirecting Standard Output and Standard Error</h4>
+<div class="subsection-level-extent" id="Redirecting-Standard-Output-and-Standard-Error">
+<h4 class="subsection"><span>3.6.4 Redirecting Standard Output and Standard Error<a class="copiable-link" href="#Redirecting-Standard-Output-and-Standard-Error"> ¶</a></span></h4>
<p>This construct allows both the
standard output (file descriptor 1) and
the standard error output (file descriptor 2)
to be redirected to the file whose name is the
-expansion of <var>word</var>.
+expansion of <var class="var">word</var>.
</p>
<p>There are two formats for redirecting standard output and
standard error:
</p><div class="example">
-<pre class="example">&><var>word</var>
+<pre class="example-preformatted">&><var class="var">word</var>
</pre></div>
<p>and
</p><div class="example">
-<pre class="example">>&<var>word</var>
+<pre class="example-preformatted">>&<var class="var">word</var>
</pre></div>
<p>Of the two forms, the first is preferred.
This is semantically equivalent to
</p><div class="example">
-<pre class="example">><var>word</var> 2>&1
+<pre class="example-preformatted">><var class="var">word</var> 2>&1
</pre></div>
-<p>When using the second form, <var>word</var> may not expand to a number or
-‘<samp>-</samp>’. If it does, other redirection operators apply
+<p>When using the second form, <var class="var">word</var> may not expand to a number or
+‘<samp class="samp">-</samp>’. If it does, other redirection operators apply
(see Duplicating File Descriptors below) for compatibility reasons.
</p>
</div>
-<div class="subsection" id="Appending-Standard-Output-and-Standard-Error">
-<h4 class="subsection">3.6.5 Appending Standard Output and Standard Error</h4>
+<div class="subsection-level-extent" id="Appending-Standard-Output-and-Standard-Error">
+<h4 class="subsection"><span>3.6.5 Appending Standard Output and Standard Error<a class="copiable-link" href="#Appending-Standard-Output-and-Standard-Error"> ¶</a></span></h4>
<p>This construct allows both the
standard output (file descriptor 1) and
the standard error output (file descriptor 2)
to be appended to the file whose name is the
-expansion of <var>word</var>.
+expansion of <var class="var">word</var>.
</p>
<p>The format for appending standard output and standard error is:
</p><div class="example">
-<pre class="example">&>><var>word</var>
+<pre class="example-preformatted">&>><var class="var">word</var>
</pre></div>
<p>This is semantically equivalent to
</p><div class="example">
-<pre class="example">>><var>word</var> 2>&1
+<pre class="example-preformatted">>><var class="var">word</var> 2>&1
</pre></div>
<p>(see Duplicating File Descriptors below).
</p>
</div>
-<div class="subsection" id="Here-Documents">
-<h4 class="subsection">3.6.6 Here Documents</h4>
+<div class="subsection-level-extent" id="Here-Documents">
+<h4 class="subsection"><span>3.6.6 Here Documents<a class="copiable-link" href="#Here-Documents"> ¶</a></span></h4>
<p>This type of redirection instructs the shell to read input from the
-current source until it reads a line containing only <var>delimiter</var>
+current source until it reads a line containing only <var class="var">delimiter</var>
(with no trailing blanks).
All of the lines read up to that point are then used as the standard
-input (or file descriptor <var>n</var> if <var>n</var> is specified) for a command.
+input (or file descriptor <var class="var">n</var> if <var class="var">n</var> is specified) for a command.
</p>
<p>The format of here-documents is:
</p><div class="example">
-<pre class="example">[<var>n</var>]<<[-]<var>word</var>
- <var>here-document</var>
-<var>delimiter</var>
+<pre class="example-preformatted">[<var class="var">n</var>]<<[−]<var class="var">word</var>
+ <var class="var">here-document</var>
+<var class="var">delimiter</var>
</pre></div>
<p>No parameter and variable expansion, command substitution,
arithmetic expansion, or filename expansion is performed on
-<var>word</var>.
+<var class="var">word</var>.
</p>
-<p>If any part of <var>word</var> is quoted, the
-<var>delimiter</var> is the result of quote removal on <var>word</var>,
+<p>If any part of <var class="var">word</var> is quoted, the
+<var class="var">delimiter</var> is the result of quote removal on <var class="var">word</var>,
and the lines in the here-document are not expanded.
-If <var>word</var> is unquoted,
-<var>delimiter</var> is <var>word</var> itself,
+If <var class="var">word</var> is unquoted,
+<var class="var">delimiter</var> is <var class="var">word</var> itself,
all lines of the here-document are subjected to
parameter expansion, command substitution, and arithmetic expansion,
-the character sequence <code>\newline</code> is ignored, and ‘<samp>\</samp>’
+the character sequence <code class="code">\newline</code> is ignored, and ‘<samp class="samp">\</samp>’
must be used to quote the characters
-‘<samp>\</samp>’, ‘<samp>$</samp>’, and ‘<samp>`</samp>’.
+‘<samp class="samp">\</samp>’, ‘<samp class="samp">$</samp>’, and ‘<samp class="samp">`</samp>’.
</p>
-<p>If the redirection operator is ‘<samp><<-</samp>’,
+<p>If the redirection operator is ‘<samp class="samp"><<-</samp>’,
then all leading tab characters are stripped from input lines and the
-line containing <var>delimiter</var>.
+line containing <var class="var">delimiter</var>.
This allows here-documents within shell scripts to be indented in a
natural fashion.
</p>
</div>
-<div class="subsection" id="Here-Strings">
-<h4 class="subsection">3.6.7 Here Strings</h4>
+<div class="subsection-level-extent" id="Here-Strings">
+<h4 class="subsection"><span>3.6.7 Here Strings<a class="copiable-link" href="#Here-Strings"> ¶</a></span></h4>
<p>A variant of here documents, the format is:
</p><div class="example">
-<pre class="example">[<var>n</var>]<<< <var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]<<< <var class="var">word</var>
</pre></div>
-<p>The <var>word</var> undergoes
+<p>The <var class="var">word</var> undergoes
tilde expansion, parameter and variable expansion,
command substitution, arithmetic expansion, and quote removal.
Filename expansion and word splitting are not performed.
The result is supplied as a single string,
with a newline appended,
to the command on its
-standard input (or file descriptor <var>n</var> if <var>n</var> is specified).
+standard input (or file descriptor <var class="var">n</var> if <var class="var">n</var> is specified).
</p>
</div>
-<div class="subsection" id="Duplicating-File-Descriptors">
-<h4 class="subsection">3.6.8 Duplicating File Descriptors</h4>
+<div class="subsection-level-extent" id="Duplicating-File-Descriptors">
+<h4 class="subsection"><span>3.6.8 Duplicating File Descriptors<a class="copiable-link" href="#Duplicating-File-Descriptors"> ¶</a></span></h4>
<p>The redirection operator
</p><div class="example">
-<pre class="example">[<var>n</var>]<&<var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]<&<var class="var">word</var>
</pre></div>
<p>is used to duplicate input file descriptors.
-If <var>word</var>
-expands to one or more digits, the file descriptor denoted by <var>n</var>
+If <var class="var">word</var>
+expands to one or more digits, the file descriptor denoted by <var class="var">n</var>
is made to be a copy of that file descriptor.
-If the digits in <var>word</var> do not specify a file descriptor open for
+If the digits in <var class="var">word</var> do not specify a file descriptor open for
input, a redirection error occurs.
-If <var>word</var>
-evaluates to ‘<samp>-</samp>’, file descriptor <var>n</var> is closed.
-If <var>n</var> is not specified, the standard input (file descriptor 0) is used.
+If <var class="var">word</var>
+evaluates to ‘<samp class="samp">-</samp>’, file descriptor <var class="var">n</var> is closed.
+If <var class="var">n</var> is not specified, the standard input (file descriptor 0) is used.
</p>
<p>The operator
</p><div class="example">
-<pre class="example">[<var>n</var>]>&<var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]>&<var class="var">word</var>
</pre></div>
<p>is used similarly to duplicate output file descriptors. If
-<var>n</var> is not specified, the standard output (file descriptor 1) is used.
-If the digits in <var>word</var> do not specify a file descriptor open for
+<var class="var">n</var> is not specified, the standard output (file descriptor 1) is used.
+If the digits in <var class="var">word</var> do not specify a file descriptor open for
output, a redirection error occurs.
-If <var>word</var>
-evaluates to ‘<samp>-</samp>’, file descriptor <var>n</var> is closed.
-As a special case, if <var>n</var> is omitted, and <var>word</var> does not
-expand to one or more digits or ‘<samp>-</samp>’, the standard output and standard
+If <var class="var">word</var>
+evaluates to ‘<samp class="samp">-</samp>’, file descriptor <var class="var">n</var> is closed.
+As a special case, if <var class="var">n</var> is omitted, and <var class="var">word</var> does not
+expand to one or more digits or ‘<samp class="samp">-</samp>’, the standard output and standard
error are redirected as described previously.
</p>
</div>
-<div class="subsection" id="Moving-File-Descriptors">
-<h4 class="subsection">3.6.9 Moving File Descriptors</h4>
+<div class="subsection-level-extent" id="Moving-File-Descriptors">
+<h4 class="subsection"><span>3.6.9 Moving File Descriptors<a class="copiable-link" href="#Moving-File-Descriptors"> ¶</a></span></h4>
<p>The redirection operator
</p><div class="example">
-<pre class="example">[<var>n</var>]<&<var>digit</var>-
+<pre class="example-preformatted">[<var class="var">n</var>]<&<var class="var">digit</var>-
</pre></div>
-<p>moves the file descriptor <var>digit</var> to file descriptor <var>n</var>,
-or the standard input (file descriptor 0) if <var>n</var> is not specified.
-<var>digit</var> is closed after being duplicated to <var>n</var>.
+<p>moves the file descriptor <var class="var">digit</var> to file descriptor <var class="var">n</var>,
+or the standard input (file descriptor 0) if <var class="var">n</var> is not specified.
+<var class="var">digit</var> is closed after being duplicated to <var class="var">n</var>.
</p>
<p>Similarly, the redirection operator
</p><div class="example">
-<pre class="example">[<var>n</var>]>&<var>digit</var>-
+<pre class="example-preformatted">[<var class="var">n</var>]>&<var class="var">digit</var>-
</pre></div>
-<p>moves the file descriptor <var>digit</var> to file descriptor <var>n</var>,
-or the standard output (file descriptor 1) if <var>n</var> is not specified.
+<p>moves the file descriptor <var class="var">digit</var> to file descriptor <var class="var">n</var>,
+or the standard output (file descriptor 1) if <var class="var">n</var> is not specified.
</p>
</div>
-<div class="subsection" id="Opening-File-Descriptors-for-Reading-and-Writing">
-<h4 class="subsection">3.6.10 Opening File Descriptors for Reading and Writing</h4>
+<div class="subsection-level-extent" id="Opening-File-Descriptors-for-Reading-and-Writing">
+<h4 class="subsection"><span>3.6.10 Opening File Descriptors for Reading and Writing<a class="copiable-link" href="#Opening-File-Descriptors-for-Reading-and-Writing"> ¶</a></span></h4>
<p>The redirection operator
</p><div class="example">
-<pre class="example">[<var>n</var>]<><var>word</var>
+<pre class="example-preformatted">[<var class="var">n</var>]<><var class="var">word</var>
</pre></div>
-<p>causes the file whose name is the expansion of <var>word</var>
+<p>causes the file whose name is the expansion of <var class="var">word</var>
to be opened for both reading and writing on file descriptor
-<var>n</var>, or on file descriptor 0 if <var>n</var>
+<var class="var">n</var>, or on file descriptor 0 if <var class="var">n</var>
is not specified. If the file does not exist, it is created.
</p>
<hr>
</div>
</div>
-<div class="section" id="Executing-Commands">
-<div class="header">
+<div class="section-level-extent" id="Executing-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Scripts" accesskey="n" rel="next">Shell Scripts</a>, Previous: <a href="#Redirections" accesskey="p" rel="prev">Redirections</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Executing-Commands-1"></span><h3 class="section">3.7 Executing Commands</h3>
+<h3 class="section" id="Executing-Commands-1"><span>3.7 Executing Commands<a class="copiable-link" href="#Executing-Commands-1"> ¶</a></span></h3>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Simple-Command-Expansion" accesskey="1">Simple Command Expansion</a></li>
<li><a href="#Command-Search-and-Execution" accesskey="2">Command Search and Execution</a></li>
<li><a href="#Command-Execution-Environment" accesskey="3">Command Execution Environment</a></li>
<li><a href="#Signals" accesskey="6">Signals</a></li>
</ul>
<hr>
-<div class="subsection" id="Simple-Command-Expansion">
-<div class="header">
+<div class="subsection-level-extent" id="Simple-Command-Expansion">
+<div class="nav-panel">
<p>
Next: <a href="#Command-Search-and-Execution" accesskey="n" rel="next">Command Search and Execution</a>, Up: <a href="#Executing-Commands" accesskey="u" rel="up">Executing Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Simple-Command-Expansion-1"></span><h4 class="subsection">3.7.1 Simple Command Expansion</h4>
-<span id="index-command-expansion"></span>
+<h4 class="subsection" id="Simple-Command-Expansion-1"><span>3.7.1 Simple Command Expansion<a class="copiable-link" href="#Simple-Command-Expansion-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-command-expansion"></a>
<p>When a simple command is executed, the shell performs the following
expansions, assignments, and redirections, from left to right, in
the following order.
</p>
-<ol>
+<ol class="enumerate">
<li> The words that the parser has marked as variable assignments (those
preceding the command name) and redirections are saved for later
processing.
</li><li> The words that are not variable assignments or redirections are
-expanded (see <a href="#Shell-Expansions">Shell Expansions</a>).
+expanded (see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>).
If any words remain after expansion, the first word
is taken to be the name of the command and the remaining words are
the arguments.
-</li><li> Redirections are performed as described above (see <a href="#Redirections">Redirections</a>).
+</li><li> Redirections are performed as described above (see <a class="pxref" href="#Redirections">Redirections</a>).
-</li><li> The text after the ‘<samp>=</samp>’ in each variable assignment undergoes tilde
+</li><li> The text after the ‘<samp class="samp">=</samp>’ in each variable assignment undergoes tilde
expansion, parameter expansion, command substitution, arithmetic expansion,
and quote removal before being assigned to the variable.
</li></ol>
</p>
<hr>
</div>
-<div class="subsection" id="Command-Search-and-Execution">
-<div class="header">
+<div class="subsection-level-extent" id="Command-Search-and-Execution">
+<div class="nav-panel">
<p>
Next: <a href="#Command-Execution-Environment" accesskey="n" rel="next">Command Execution Environment</a>, Previous: <a href="#Simple-Command-Expansion" accesskey="p" rel="prev">Simple Command Expansion</a>, Up: <a href="#Executing-Commands" accesskey="u" rel="up">Executing Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Command-Search-and-Execution-1"></span><h4 class="subsection">3.7.2 Command Search and Execution</h4>
-<span id="index-command-execution"></span>
-<span id="index-command-search"></span>
+<h4 class="subsection" id="Command-Search-and-Execution-1"><span>3.7.2 Command Search and Execution<a class="copiable-link" href="#Command-Search-and-Execution-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-command-execution"></a>
+<a class="index-entry-id" id="index-command-search"></a>
<p>After a command has been split into words, if it results in a
simple command and an optional list of arguments, the shell performs
the following actions.
</p>
-<ol>
+<ol class="enumerate">
<li> If the command name contains no slashes, the shell attempts to
locate it. If there exists a shell function by that name, that
-function is invoked as described in <a href="#Shell-Functions">Shell Functions</a>.
+function is invoked as described in <a class="ref" href="#Shell-Functions">Shell Functions</a>.
</li><li> If the name does not match a function, the shell searches for
it in the list of shell builtins. If a match is found, that
</li><li> If the name is neither a shell function nor a builtin,
and contains no slashes, Bash searches each element of
-<code>$PATH</code> for a directory containing an executable file
+<code class="env">$PATH</code> for a directory containing an executable file
by that name. Bash uses a hash table to remember the full
-pathnames of executable files to avoid multiple <code>PATH</code> searches
-(see the description of <code>hash</code> in <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-A full search of the directories in <code>$PATH</code>
+pathnames of executable files to avoid multiple <code class="env">PATH</code> searches
+(see the description of <code class="code">hash</code> in <a class="ref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+A full search of the directories in <code class="env">$PATH</code>
is performed only if the command is not found in the hash table.
If the search is unsuccessful, the shell searches for a defined shell
-function named <code>command_not_found_handle</code>.
+function named <code class="code">command_not_found_handle</code>.
If that function exists, it is invoked in a separate execution environment
with the original command and
the original command’s arguments as its arguments, and the function’s
</li><li> If this execution fails because the file is not in executable
format, and the file is not a directory, it is assumed to be a
-<em>shell script</em> and the shell executes it as described in
-<a href="#Shell-Scripts">Shell Scripts</a>.
+<em class="dfn">shell script</em> and the shell executes it as described in
+<a class="ref" href="#Shell-Scripts">Shell Scripts</a>.
</li><li> If the command was not begun asynchronously, the shell waits for
the command to complete and collects its exit status.
<hr>
</div>
-<div class="subsection" id="Command-Execution-Environment">
-<div class="header">
+<div class="subsection-level-extent" id="Command-Execution-Environment">
+<div class="nav-panel">
<p>
Next: <a href="#Environment" accesskey="n" rel="next">Environment</a>, Previous: <a href="#Command-Search-and-Execution" accesskey="p" rel="prev">Command Search and Execution</a>, Up: <a href="#Executing-Commands" accesskey="u" rel="up">Executing Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Command-Execution-Environment-1"></span><h4 class="subsection">3.7.3 Command Execution Environment</h4>
-<span id="index-execution-environment"></span>
+<h4 class="subsection" id="Command-Execution-Environment-1"><span>3.7.3 Command Execution Environment<a class="copiable-link" href="#Command-Execution-Environment-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-execution-environment"></a>
-<p>The shell has an <em>execution environment</em>, which consists of the
+<p>The shell has an <em class="dfn">execution environment</em>, which consists of the
following:
</p>
-<ul>
-<li> open files inherited by the shell at invocation, as modified by
-redirections supplied to the <code>exec</code> builtin
+<ul class="itemize mark-bullet">
+<li>open files inherited by the shell at invocation, as modified by
+redirections supplied to the <code class="code">exec</code> builtin
-</li><li> the current working directory as set by <code>cd</code>, <code>pushd</code>, or
-<code>popd</code>, or inherited by the shell at invocation
+</li><li>the current working directory as set by <code class="code">cd</code>, <code class="code">pushd</code>, or
+<code class="code">popd</code>, or inherited by the shell at invocation
-</li><li> the file creation mode mask as set by <code>umask</code> or inherited from
+</li><li>the file creation mode mask as set by <code class="code">umask</code> or inherited from
the shell’s parent
-</li><li> current traps set by <code>trap</code>
+</li><li>current traps set by <code class="code">trap</code>
-</li><li> shell parameters that are set by variable assignment or with <code>set</code>
+</li><li>shell parameters that are set by variable assignment or with <code class="code">set</code>
or inherited from the shell’s parent in the environment
-</li><li> shell functions defined during execution or inherited from the shell’s
+</li><li>shell functions defined during execution or inherited from the shell’s
parent in the environment
-</li><li> options enabled at invocation (either by default or with command-line
-arguments) or by <code>set</code>
+</li><li>options enabled at invocation (either by default or with command-line
+arguments) or by <code class="code">set</code>
-</li><li> options enabled by <code>shopt</code> (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+</li><li>options enabled by <code class="code">shopt</code> (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
-</li><li> shell aliases defined with <code>alias</code> (see <a href="#Aliases">Aliases</a>)
+</li><li>shell aliases defined with <code class="code">alias</code> (see <a class="pxref" href="#Aliases">Aliases</a>)
-</li><li> various process <small>ID</small>s, including those of background jobs
-(see <a href="#Lists">Lists of Commands</a>), the value of <code>$$</code>, and the value of
-<code>$PPID</code>
+</li><li>various process <small class="sc">ID</small>s, including those of background jobs
+(see <a class="pxref" href="#Lists">Lists of Commands</a>), the value of <code class="code">$$</code>, and the value of
+<code class="env">$PPID</code>
</li></ul>
the following. Unless otherwise noted, the values are inherited
from the shell.
</p>
-<ul>
-<li> the shell’s open files, plus any modifications and additions specified
+<ul class="itemize mark-bullet">
+<li>the shell’s open files, plus any modifications and additions specified
by redirections to the command
-</li><li> the current working directory
+</li><li>the current working directory
-</li><li> the file creation mode mask
+</li><li>the file creation mode mask
-</li><li> shell variables and functions marked for export, along with variables
-exported for the command, passed in the environment (see <a href="#Environment">Environment</a>)
+</li><li>shell variables and functions marked for export, along with variables
+exported for the command, passed in the environment (see <a class="pxref" href="#Environment">Environment</a>)
-</li><li> traps caught by the shell are reset to the values inherited from the
+</li><li>traps caught by the shell are reset to the values inherited from the
shell’s parent, and traps ignored by the shell are ignored
</li></ul>
<p>A command invoked in this separate environment cannot affect the
shell’s execution environment.
</p>
-<p>A <em>subshell</em> is a copy of the shell process.
+<p>A <em class="dfn">subshell</em> is a copy of the shell process.
</p>
<p>Command substitution, commands grouped with parentheses,
and asynchronous commands are invoked in a
in a subshell environment. Changes made to the subshell environment
cannot affect the shell’s execution environment.
</p>
-<p>Subshells spawned to execute command substitutions inherit the value of
-the <samp>-e</samp> option from the parent shell. When not in <small>POSIX</small> mode,
-Bash clears the <samp>-e</samp> option in such subshells.
-</p>
-<p>If a command is followed by a ‘<samp>&</samp>’ and job control is not active, the
-default standard input for the command is the empty file <samp>/dev/null</samp>.
+<p>When the shell is in <small class="sc">POSIX</small> mode,
+subshells spawned to execute command substitutions inherit the value of
+the <samp class="option">-e</samp> option from the parent shell.
+When not in <small class="sc">POSIX</small> mode,
+Bash clears the <samp class="option">-e</samp> option in such subshells
+See the description of the <code class="code">inherit_errexit</code> shell option
+(see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>) for how to control this behavior when not
+in <small class="sc">POSIX</small> mode.
+</p>
+<p>If a command is followed by a ‘<samp class="samp">&</samp>’ and job control is not active, the
+default standard input for the command is the empty file <samp class="file">/dev/null</samp>.
Otherwise, the invoked command inherits the file descriptors of the calling
shell as modified by redirections.
</p>
<hr>
</div>
-<div class="subsection" id="Environment">
-<div class="header">
+<div class="subsection-level-extent" id="Environment">
+<div class="nav-panel">
<p>
Next: <a href="#Exit-Status" accesskey="n" rel="next">Exit Status</a>, Previous: <a href="#Command-Execution-Environment" accesskey="p" rel="prev">Command Execution Environment</a>, Up: <a href="#Executing-Commands" accesskey="u" rel="up">Executing Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Environment-1"></span><h4 class="subsection">3.7.4 Environment</h4>
-<span id="index-environment"></span>
+<h4 class="subsection" id="Environment-1"><span>3.7.4 Environment<a class="copiable-link" href="#Environment-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-environment"></a>
<p>When a program is invoked it is given an array of strings
-called the <em>environment</em>.
-This is a list of name-value pairs, of the form <code>name=value</code>.
+called the <em class="dfn">environment</em>.
+This is a list of name-value pairs, of the form <code class="code">name=value</code>.
</p>
<p>Bash provides several ways to manipulate the environment.
On invocation, the shell scans its own environment and
creates a parameter for each name found, automatically marking
-it for <code>export</code>
+it for <code class="code">export</code>
to child processes. Executed commands inherit the environment.
-The <code>export</code> and ‘<samp>declare -x</samp>’
+The <code class="code">export</code> and ‘<samp class="samp">declare -x</samp>’
commands allow parameters and functions to be added to and
deleted from the environment. If the value of a parameter
in the environment is modified, the new value becomes part
of the environment, replacing the old. The environment
inherited by any executed command consists of the shell’s
initial environment, whose values may be modified in the shell,
-less any pairs removed by the <code>unset</code> and ‘<samp>export -n</samp>’
-commands, plus any additions via the <code>export</code> and
-‘<samp>declare -x</samp>’ commands.
+less any pairs removed by the <code class="code">unset</code> and ‘<samp class="samp">export -n</samp>’
+commands, plus any additions via the <code class="code">export</code> and
+‘<samp class="samp">declare -x</samp>’ commands.
</p>
<p>The environment for any simple command
or function may be augmented temporarily by prefixing it with
-parameter assignments, as described in <a href="#Shell-Parameters">Shell Parameters</a>.
+parameter assignments, as described in <a class="ref" href="#Shell-Parameters">Shell Parameters</a>.
These assignment statements affect only the environment seen
by that command.
</p>
-<p>If the <samp>-k</samp> option is set (see <a href="#The-Set-Builtin">The Set Builtin</a>), then all
+<p>If the <samp class="option">-k</samp> option is set (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>), then all
parameter assignments are placed in the environment for a command,
not just those that precede the command name.
</p>
-<p>When Bash invokes an external command, the variable ‘<samp>$_</samp>’
+<p>When Bash invokes an external command, the variable ‘<samp class="samp">$_</samp>’
is set to the full pathname of the command and passed to that
command in its environment.
</p>
<hr>
</div>
-<div class="subsection" id="Exit-Status">
-<div class="header">
+<div class="subsection-level-extent" id="Exit-Status">
+<div class="nav-panel">
<p>
Next: <a href="#Signals" accesskey="n" rel="next">Signals</a>, Previous: <a href="#Environment" accesskey="p" rel="prev">Environment</a>, Up: <a href="#Executing-Commands" accesskey="u" rel="up">Executing Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Exit-Status-1"></span><h4 class="subsection">3.7.5 Exit Status</h4>
-<span id="index-exit-status-1"></span>
+<h4 class="subsection" id="Exit-Status-1"><span>3.7.5 Exit Status<a class="copiable-link" href="#Exit-Status-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-exit-status-1"></a>
<p>The exit status of an executed command is the value returned by the
-<code>waitpid</code> system call or equivalent function. Exit statuses
+<code class="code">waitpid</code> system call or equivalent function. Exit statuses
fall between 0 and 255, though, as explained below, the shell may
use values above 125 specially. Exit statuses from shell builtins and
compound commands are also limited to this range. Under certain
This seemingly counter-intuitive scheme is used so there
is one well-defined way to indicate success and a variety of
ways to indicate various failure modes.
-When a command terminates on a fatal signal whose number is <var>N</var>,
-Bash uses the value 128+<var>N</var> as the exit status.
+When a command terminates on a fatal signal whose number is <var class="var">N</var>,
+Bash uses the value 128+<var class="var">N</var> as the exit status.
</p>
<p>If a command is not found, the child process created to
execute it returns a status of 127. If a command is found
the exit status is greater than zero.
</p>
<p>The exit status is used by the Bash conditional commands
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>) and some of the list
-constructs (see <a href="#Lists">Lists of Commands</a>).
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>) and some of the list
+constructs (see <a class="pxref" href="#Lists">Lists of Commands</a>).
</p>
<p>All of the Bash builtins return an exit status of zero if they succeed
and a non-zero status on failure, so they may be used by the
generally invalid options or missing arguments.
</p>
<p>The exit status of the last command is available in the special
-parameter $? (see <a href="#Special-Parameters">Special Parameters</a>).
+parameter $? (see <a class="pxref" href="#Special-Parameters">Special Parameters</a>).
</p>
<hr>
</div>
-<div class="subsection" id="Signals">
-<div class="header">
+<div class="subsection-level-extent" id="Signals">
+<div class="nav-panel">
<p>
Previous: <a href="#Exit-Status" accesskey="p" rel="prev">Exit Status</a>, Up: <a href="#Executing-Commands" accesskey="u" rel="up">Executing Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Signals-1"></span><h4 class="subsection">3.7.6 Signals</h4>
-<span id="index-signal-handling"></span>
+<h4 class="subsection" id="Signals-1"><span>3.7.6 Signals<a class="copiable-link" href="#Signals-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-signal-handling"></a>
<p>When Bash is interactive, in the absence of any traps, it ignores
-<code>SIGTERM</code> (so that ‘<samp>kill 0</samp>’ does not kill an interactive shell),
-and <code>SIGINT</code>
-is caught and handled (so that the <code>wait</code> builtin is interruptible).
-When Bash receives a <code>SIGINT</code>, it breaks out of any executing loops.
-In all cases, Bash ignores <code>SIGQUIT</code>.
-If job control is in effect (see <a href="#Job-Control">Job Control</a>), Bash
-ignores <code>SIGTTIN</code>, <code>SIGTTOU</code>, and <code>SIGTSTP</code>.
+<code class="code">SIGTERM</code> (so that ‘<samp class="samp">kill 0</samp>’ does not kill an interactive shell),
+and <code class="code">SIGINT</code>
+is caught and handled (so that the <code class="code">wait</code> builtin is interruptible).
+When Bash receives a <code class="code">SIGINT</code>, it breaks out of any executing loops.
+In all cases, Bash ignores <code class="code">SIGQUIT</code>.
+If job control is in effect (see <a class="pxref" href="#Job-Control">Job Control</a>), Bash
+ignores <code class="code">SIGTTIN</code>, <code class="code">SIGTTOU</code>, and <code class="code">SIGTSTP</code>.
</p>
<p>Non-builtin commands started by Bash have signal handlers set to the
values inherited by the shell from its parent.
When job control is not in effect, asynchronous commands
-ignore <code>SIGINT</code> and <code>SIGQUIT</code> in addition to these inherited
+ignore <code class="code">SIGINT</code> and <code class="code">SIGQUIT</code> in addition to these inherited
handlers.
Commands run as a result of
command substitution ignore the keyboard-generated job control signals
-<code>SIGTTIN</code>, <code>SIGTTOU</code>, and <code>SIGTSTP</code>.
+<code class="code">SIGTTIN</code>, <code class="code">SIGTTOU</code>, and <code class="code">SIGTSTP</code>.
</p>
-<p>The shell exits by default upon receipt of a <code>SIGHUP</code>.
-Before exiting, an interactive shell resends the <code>SIGHUP</code> to
+<p>The shell exits by default upon receipt of a <code class="code">SIGHUP</code>.
+Before exiting, an interactive shell resends the <code class="code">SIGHUP</code> to
all jobs, running or stopped.
-Stopped jobs are sent <code>SIGCONT</code> to ensure that they receive
-the <code>SIGHUP</code>.
-To prevent the shell from sending the <code>SIGHUP</code> signal to a
+Stopped jobs are sent <code class="code">SIGCONT</code> to ensure that they receive
+the <code class="code">SIGHUP</code>.
+To prevent the shell from sending the <code class="code">SIGHUP</code> signal to a
particular job, it should be removed
-from the jobs table with the <code>disown</code>
-builtin (see <a href="#Job-Control-Builtins">Job Control Builtins</a>) or marked
-to not receive <code>SIGHUP</code> using <code>disown -h</code>.
+from the jobs table with the <code class="code">disown</code>
+builtin (see <a class="pxref" href="#Job-Control-Builtins">Job Control Builtins</a>) or marked
+to not receive <code class="code">SIGHUP</code> using <code class="code">disown -h</code>.
</p>
-<p>If the <code>huponexit</code> shell option has been set with <code>shopt</code>
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), Bash sends a <code>SIGHUP</code> to all jobs when
+<p>If the <code class="code">huponexit</code> shell option has been set with <code class="code">shopt</code>
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>), Bash sends a <code class="code">SIGHUP</code> to all jobs when
an interactive login shell exits.
</p>
<p>If Bash is waiting for a command to complete and receives a signal
for which a trap has been set, the trap will not be executed until
the command completes.
When Bash is waiting for an asynchronous
-command via the <code>wait</code> builtin, the reception of a signal for
-which a trap has been set will cause the <code>wait</code> builtin to return
+command via the <code class="code">wait</code> builtin, the reception of a signal for
+which a trap has been set will cause the <code class="code">wait</code> builtin to return
immediately with an exit status greater than 128, immediately after
which the trap is executed.
</p>
<p>When job control is not enabled, and Bash is waiting for a foreground
command to complete, the shell receives keyboard-generated signals
-such as <code>SIGINT</code> (usually generated by ‘<samp>^C</samp>’) that users
+such as <code class="code">SIGINT</code> (usually generated by ‘<samp class="samp">^C</samp>’) that users
commonly intend to send to that command.
This happens because the shell and the command are in the same process
-group as the terminal, and ‘<samp>^C</samp>’ sends <code>SIGINT</code> to all processes
+group as the terminal, and ‘<samp class="samp">^C</samp>’ sends <code class="code">SIGINT</code> to all processes
in that process group.
-See <a href="#Job-Control">Job Control</a>, for a more in-depth discussion of process groups.
+See <a class="ref" href="#Job-Control">Job Control</a>, for a more in-depth discussion of process groups.
</p>
-<p>When Bash is running without job control enabled and receives <code>SIGINT</code>
+<p>When Bash is running without job control enabled and receives <code class="code">SIGINT</code>
while waiting for a foreground command, it waits until that foreground
-command terminates and then decides what to do about the <code>SIGINT</code>:
+command terminates and then decides what to do about the <code class="code">SIGINT</code>:
</p>
-<ol>
-<li> If the command terminates due to the <code>SIGINT</code>, Bash concludes
+<ol class="enumerate">
+<li> If the command terminates due to the <code class="code">SIGINT</code>, Bash concludes
that the user meant to end the entire script, and acts on the
-<code>SIGINT</code> (e.g., by running a <code>SIGINT</code> trap or exiting itself);
+<code class="code">SIGINT</code> (e.g., by running a <code class="code">SIGINT</code> trap or exiting itself);
-</li><li> If the pipeline does not terminate due to <code>SIGINT</code>, the program
-handled the <code>SIGINT</code> itself and did not treat it as a fatal signal.
-In that case, Bash does not treat <code>SIGINT</code> as a fatal signal,
-either, instead assuming that the <code>SIGINT</code> was used as part of the
-program’s normal operation (e.g., <code>emacs</code> uses it to abort editing
+</li><li> If the pipeline does not terminate due to <code class="code">SIGINT</code>, the program
+handled the <code class="code">SIGINT</code> itself and did not treat it as a fatal signal.
+In that case, Bash does not treat <code class="code">SIGINT</code> as a fatal signal,
+either, instead assuming that the <code class="code">SIGINT</code> was used as part of the
+program’s normal operation (e.g., <code class="command">emacs</code> uses it to abort editing
commands) or deliberately discarded. However, Bash will run any
-trap set on <code>SIGINT</code>, as it does with any other trapped signal it
+trap set on <code class="code">SIGINT</code>, as it does with any other trapped signal it
receives while it is waiting for the foreground command to
complete, for compatibility.
</li></ol>
<hr>
</div>
</div>
-<div class="section" id="Shell-Scripts">
-<div class="header">
+<div class="section-level-extent" id="Shell-Scripts">
+<div class="nav-panel">
<p>
Previous: <a href="#Executing-Commands" accesskey="p" rel="prev">Executing Commands</a>, Up: <a href="#Basic-Shell-Features" accesskey="u" rel="up">Basic Shell Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Scripts-1"></span><h3 class="section">3.8 Shell Scripts</h3>
-<span id="index-shell-script"></span>
+<h3 class="section" id="Shell-Scripts-1"><span>3.8 Shell Scripts<a class="copiable-link" href="#Shell-Scripts-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-shell-script"></a>
<p>A shell script is a text file containing shell commands. When such
a file is used as the first non-option argument when invoking Bash,
-and neither the <samp>-c</samp> nor <samp>-s</samp> option is supplied
-(see <a href="#Invoking-Bash">Invoking Bash</a>),
+and neither the <samp class="option">-c</samp> nor <samp class="option">-s</samp> option is supplied
+(see <a class="pxref" href="#Invoking-Bash">Invoking Bash</a>),
Bash reads and executes commands from the file, then exits. This
mode of operation creates a non-interactive shell. The shell first
searches for the file in the current directory, and looks in the
-directories in <code>$PATH</code> if not found there.
+directories in <code class="env">$PATH</code> if not found there.
</p>
<p>When Bash runs
-a shell script, it sets the special parameter <code>0</code> to the name
+a shell script, it sets the special parameter <code class="code">0</code> to the name
of the file, rather than the name of the shell, and the positional
parameters are set to the remaining arguments, if any are given.
If no additional arguments are supplied, the positional parameters
are unset.
</p>
-<p>A shell script may be made executable by using the <code>chmod</code> command
+<p>A shell script may be made executable by using the <code class="code">chmod</code> command
to turn on the execute bit. When Bash finds such a file while
-searching the <code>$PATH</code> for a command, it creates a
+searching the <code class="env">$PATH</code> for a command, it creates a
new instance of itself
to execute it.
In other words, executing
</p><div class="example">
-<pre class="example">filename <var>arguments</var>
+<pre class="example-preformatted">filename <var class="var">arguments</var>
</pre></div>
<p>is equivalent to executing
</p><div class="example">
-<pre class="example">bash filename <var>arguments</var>
+<pre class="example-preformatted">bash filename <var class="var">arguments</var>
</pre></div>
-<p>if <code>filename</code> is an executable shell script.
+<p>if <code class="code">filename</code> is an executable shell script.
This subshell reinitializes itself, so that the effect is as if a
new shell had been invoked to interpret the script, with the
exception that the locations of commands remembered by the parent
-(see the description of <code>hash</code> in <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
+(see the description of <code class="code">hash</code> in <a class="ref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
are retained by the child.
</p>
<p>Most versions of Unix make this a part of the operating system’s command
execution mechanism. If the first line of a script begins with
-the two characters ‘<samp>#!</samp>’, the remainder of the line specifies
+the two characters ‘<samp class="samp">#!</samp>’, the remainder of the line specifies
an interpreter for the program and, depending on the operating system, one
or more optional arguments for that interpreter.
-Thus, you can specify Bash, <code>awk</code>, Perl, or some other
+Thus, you can specify Bash, <code class="code">awk</code>, Perl, or some other
interpreter and write the rest of the script file in that language.
</p>
<p>The arguments to the interpreter
name and a single argument to a maximum of 32 characters, so it’s not
portable to assume that using more than one argument will work.
</p>
-<p>Bash scripts often begin with <code>#! /bin/bash</code> (assuming that
-Bash has been installed in <samp>/bin</samp>), since this ensures that
+<p>Bash scripts often begin with <code class="code">#! /bin/bash</code> (assuming that
+Bash has been installed in <samp class="file">/bin</samp>), since this ensures that
Bash will be used to interpret the script, even if it is executed
-under another shell. It’s a common idiom to use <code>env</code> to find
-<code>bash</code> even if it’s been installed in another directory:
-<code>#!/usr/bin/env bash</code> will find the first occurrence of <code>bash</code>
-in <code>$PATH</code>.
+under another shell. It’s a common idiom to use <code class="code">env</code> to find
+<code class="code">bash</code> even if it’s been installed in another directory:
+<code class="code">#!/usr/bin/env bash</code> will find the first occurrence of <code class="code">bash</code>
+in <code class="env">$PATH</code>.
</p>
<hr>
</div>
</div>
-<div class="chapter" id="Shell-Builtin-Commands">
-<div class="header">
+<div class="chapter-level-extent" id="Shell-Builtin-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Variables" accesskey="n" rel="next">Shell Variables</a>, Previous: <a href="#Basic-Shell-Features" accesskey="p" rel="prev">Basic Shell Features</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Builtin-Commands-1"></span><h2 class="chapter">4 Shell Builtin Commands</h2>
+<h2 class="chapter" id="Shell-Builtin-Commands-1"><span>4 Shell Builtin Commands<a class="copiable-link" href="#Shell-Builtin-Commands-1"> ¶</a></span></h2>
<p>Builtin commands are contained within the shell itself.
When the name of a builtin command is used as the first word of
-a simple command (see <a href="#Simple-Commands">Simple Commands</a>), the shell executes
+a simple command (see <a class="pxref" href="#Simple-Commands">Simple Commands</a>), the shell executes
the command directly, without invoking another program.
Builtin commands are necessary to implement functionality impossible
or inconvenient to obtain with separate utilities.
</p>
<p>Several builtin commands are described in other chapters: builtin
commands which provide the Bash interface to the job control
-facilities (see <a href="#Job-Control-Builtins">Job Control Builtins</a>), the directory stack
-(see <a href="#Directory-Stack-Builtins">Directory Stack Builtins</a>), the command history
-(see <a href="#Bash-History-Builtins">Bash History Builtins</a>), and the programmable completion
-facilities (see <a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a>).
+facilities (see <a class="pxref" href="#Job-Control-Builtins">Job Control Builtins</a>), the directory stack
+(see <a class="pxref" href="#Directory-Stack-Builtins">Directory Stack Builtins</a>), the command history
+(see <a class="pxref" href="#Bash-History-Builtins">Bash History Builtins</a>), and the programmable completion
+facilities (see <a class="pxref" href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a>).
</p>
-<p>Many of the builtins have been extended by <small>POSIX</small> or Bash.
+<p>Many of the builtins have been extended by <small class="sc">POSIX</small> or Bash.
</p>
<p>Unless otherwise noted, each builtin command documented as accepting
-options preceded by ‘<samp>-</samp>’ accepts ‘<samp>--</samp>’
+options preceded by ‘<samp class="samp">-</samp>’ accepts ‘<samp class="samp">--</samp>’
to signify the end of the options.
-The <code>:</code>, <code>true</code>, <code>false</code>, and <code>test</code>/<code>[</code>
-builtins do not accept options and do not treat ‘<samp>--</samp>’ specially.
-The <code>exit</code>, <code>logout</code>, <code>return</code>,
-<code>break</code>, <code>continue</code>, <code>let</code>,
-and <code>shift</code> builtins accept and process arguments beginning
-with ‘<samp>-</samp>’ without requiring ‘<samp>--</samp>’.
+The <code class="code">:</code>, <code class="code">true</code>, <code class="code">false</code>, and <code class="code">test</code>/<code class="code">[</code>
+builtins do not accept options and do not treat ‘<samp class="samp">--</samp>’ specially.
+The <code class="code">exit</code>, <code class="code">logout</code>, <code class="code">return</code>,
+<code class="code">break</code>, <code class="code">continue</code>, <code class="code">let</code>,
+and <code class="code">shift</code> builtins accept and process arguments beginning
+with ‘<samp class="samp">-</samp>’ without requiring ‘<samp class="samp">--</samp>’.
Other builtins that accept arguments but are not specified as accepting
-options interpret arguments beginning with ‘<samp>-</samp>’ as invalid options and
-require ‘<samp>--</samp>’ to prevent this interpretation.
+options interpret arguments beginning with ‘<samp class="samp">-</samp>’ as invalid options and
+require ‘<samp class="samp">--</samp>’ to prevent this interpretation.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Bourne-Shell-Builtins" accesskey="1">Bourne Shell Builtins</a></li>
<li><a href="#Bash-Builtins" accesskey="2">Bash Builtin Commands</a></li>
<li><a href="#Modifying-Shell-Behavior" accesskey="3">Modifying Shell Behavior</a></li>
<li><a href="#Special-Builtins" accesskey="4">Special Builtins</a></li>
</ul>
<hr>
-<div class="section" id="Bourne-Shell-Builtins">
-<div class="header">
+<div class="section-level-extent" id="Bourne-Shell-Builtins">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-Builtins" accesskey="n" rel="next">Bash Builtin Commands</a>, Up: <a href="#Shell-Builtin-Commands" accesskey="u" rel="up">Shell Builtin Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bourne-Shell-Builtins-1"></span><h3 class="section">4.1 Bourne Shell Builtins</h3>
+<h3 class="section" id="Bourne-Shell-Builtins-1"><span>4.1 Bourne Shell Builtins<a class="copiable-link" href="#Bourne-Shell-Builtins-1"> ¶</a></span></h3>
<p>The following shell builtin commands are inherited from the Bourne Shell.
-These commands are implemented as specified by the <small>POSIX</small> standard.
+These commands are implemented as specified by the <small class="sc">POSIX</small> standard.
</p>
-<dl compact="compact">
-<dt id='index-_003a'><span><code>: <span class="roman">(a colon)</span></code><a href='#index-_003a' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-_003a"></a><span><code class="code">: <span class="r">(a colon)</span></code><a class="copiable-link" href="#index-_003a"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">: [<var>arguments</var>]
+<pre class="example-preformatted">: [<var class="var">arguments</var>]
</pre></div>
-<p>Do nothing beyond expanding <var>arguments</var> and performing redirections.
+<p>Do nothing beyond expanding <var class="var">arguments</var> and performing redirections.
The return status is zero.
</p>
</dd>
-<dt id='index-_002e'><span><code>. <span class="roman">(a period)</span></code><a href='#index-_002e' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-_002e"></a><span><code class="code">. <span class="r">(a period)</span></code><a class="copiable-link" href="#index-_002e"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">. <var>filename</var> [<var>arguments</var>]
+<pre class="example-preformatted">. <var class="var">filename</var> [<var class="var">arguments</var>]
</pre></div>
-<p>Read and execute commands from the <var>filename</var> argument in the
-current shell context. If <var>filename</var> does not contain a slash,
-the <code>PATH</code> variable is used to find <var>filename</var>,
-but <var>filename</var> does not need to be executable.
-When Bash is not in <small>POSIX</small> mode, it searches the current directory
-if <var>filename</var> is not found in <code>$PATH</code>.
-If any <var>arguments</var> are supplied, they become the positional
-parameters when <var>filename</var> is executed. Otherwise the positional
+<p>Read and execute commands from the <var class="var">filename</var> argument in the
+current shell context. If <var class="var">filename</var> does not contain a slash,
+the <code class="env">PATH</code> variable is used to find <var class="var">filename</var>,
+but <var class="var">filename</var> does not need to be executable.
+When Bash is not in <small class="sc">POSIX</small> mode, it searches the current directory
+if <var class="var">filename</var> is not found in <code class="env">$PATH</code>.
+If any <var class="var">arguments</var> are supplied, they become the positional
+parameters when <var class="var">filename</var> is executed. Otherwise the positional
parameters are unchanged.
-If the <samp>-T</samp> option is enabled, <code>.</code> inherits any trap on
-<code>DEBUG</code>; if it is not, any <code>DEBUG</code> trap string is saved and
-restored around the call to <code>.</code>, and <code>.</code> unsets the
-<code>DEBUG</code> trap while it executes.
-If <samp>-T</samp> is not set, and the sourced file changes
-the <code>DEBUG</code> trap, the new value is retained when <code>.</code> completes.
+If the <samp class="option">-T</samp> option is enabled, <code class="code">.</code> inherits any trap on
+<code class="code">DEBUG</code>; if it is not, any <code class="code">DEBUG</code> trap string is saved and
+restored around the call to <code class="code">.</code>, and <code class="code">.</code> unsets the
+<code class="code">DEBUG</code> trap while it executes.
+If <samp class="option">-T</samp> is not set, and the sourced file changes
+the <code class="code">DEBUG</code> trap, the new value is retained when <code class="code">.</code> completes.
The return status is the exit status of the last command executed, or
-zero if no commands are executed. If <var>filename</var> is not found, or
+zero if no commands are executed. If <var class="var">filename</var> is not found, or
cannot be read, the return status is non-zero.
-This builtin is equivalent to <code>source</code>.
+This builtin is equivalent to <code class="code">source</code>.
</p>
</dd>
-<dt id='index-break'><span><code>break</code><a href='#index-break' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-break"></a><span><code class="code">break</code><a class="copiable-link" href="#index-break"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">break [<var>n</var>]
+<pre class="example-preformatted">break [<var class="var">n</var>]
</pre></div>
-<p>Exit from a <code>for</code>, <code>while</code>, <code>until</code>, or <code>select</code> loop.
-If <var>n</var> is supplied, the <var>n</var>th enclosing loop is exited.
-<var>n</var> must be greater than or equal to 1.
-The return status is zero unless <var>n</var> is not greater than or equal to 1.
+<p>Exit from a <code class="code">for</code>, <code class="code">while</code>, <code class="code">until</code>, or <code class="code">select</code> loop.
+If <var class="var">n</var> is supplied, the <var class="var">n</var>th enclosing loop is exited.
+<var class="var">n</var> must be greater than or equal to 1.
+The return status is zero unless <var class="var">n</var> is not greater than or equal to 1.
</p>
</dd>
-<dt id='index-cd'><span><code>cd</code><a href='#index-cd' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-cd"></a><span><code class="code">cd</code><a class="copiable-link" href="#index-cd"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">cd [-L|[-P [-e]]] [-@] [<var>directory</var>]
+<pre class="example-preformatted">cd [-L|[-P [-e]]] [-@] [<var class="var">directory</var>]
</pre></div>
-<p>Change the current working directory to <var>directory</var>.
-If <var>directory</var> is not supplied, the value of the <code>HOME</code>
+<p>Change the current working directory to <var class="var">directory</var>.
+If <var class="var">directory</var> is not supplied, the value of the <code class="env">HOME</code>
shell variable is used.
If the shell variable
-<code>CDPATH</code> exists, it is used as a search path:
-each directory name in <code>CDPATH</code> is searched for
-<var>directory</var>, with alternative directory names in <code>CDPATH</code>
-separated by a colon (‘<samp>:</samp>’).
-If <var>directory</var> begins with a slash, <code>CDPATH</code> is not used.
+<code class="env">CDPATH</code> exists, <code class="code">cd</code> uses it as a search path:
+<code class="code">cd</code> searches each directory name in <code class="env">CDPATH</code> for
+<var class="var">directory</var>, with alternative directory names in <code class="env">CDPATH</code>
+separated by a colon (‘<samp class="samp">:</samp>’).
+If <var class="var">directory</var> begins with a slash, <code class="env">CDPATH</code> is not used.
</p>
-<p>The <samp>-P</samp> option means to not follow symbolic links: symbolic links
-are resolved while <code>cd</code> is traversing <var>directory</var> and before
-processing an instance of ‘<samp>..</samp>’ in <var>directory</var>.
+<p>The <samp class="option">-P</samp> option means to not follow symbolic links: symbolic links
+are resolved while <code class="code">cd</code> is traversing <var class="var">directory</var> and before
+processing an instance of ‘<samp class="samp">..</samp>’ in <var class="var">directory</var>.
</p>
-<p>By default, or when the <samp>-L</samp> option is supplied, symbolic links
-in <var>directory</var> are resolved after <code>cd</code> processes an instance
-of ‘<samp>..</samp>’ in <var>directory</var>.
+<p>By default, or when the <samp class="option">-L</samp> option is supplied, symbolic links
+in <var class="var">directory</var> are resolved after <code class="code">cd</code> processes an instance
+of ‘<samp class="samp">..</samp>’ in <var class="var">directory</var>.
</p>
-<p>If ‘<samp>..</samp>’ appears in <var>directory</var>, it is processed by removing the
+<p>If ‘<samp class="samp">..</samp>’ appears in <var class="var">directory</var>, it is processed by removing the
immediately preceding pathname component, back to a slash or the beginning
-of <var>directory</var>.
+of <var class="var">directory</var>.
</p>
-<p>If the <samp>-e</samp> option is supplied with <samp>-P</samp>
+<p>If the <samp class="option">-e</samp> option is supplied with <samp class="option">-P</samp>
and the current working directory cannot be successfully determined
-after a successful directory change, <code>cd</code> will return an unsuccessful
+after a successful directory change, <code class="code">cd</code> will return an unsuccessful
status.
</p>
-<p>On systems that support it, the <samp>-@</samp> option presents the extended
+<p>On systems that support it, the <samp class="option">-@</samp> option presents the extended
attributes associated with a file as a directory.
</p>
-<p>If <var>directory</var> is ‘<samp>-</samp>’, it is converted to <code>$OLDPWD</code>
+<p>If <var class="var">directory</var> is ‘<samp class="samp">-</samp>’, it is converted to <code class="env">$OLDPWD</code>
before the directory change is attempted.
</p>
-<p>If a non-empty directory name from <code>CDPATH</code> is used, or if
-‘<samp>-</samp>’ is the first argument, and the directory change is
+<p>If a non-empty directory name from <code class="env">CDPATH</code> is used, or if
+‘<samp class="samp">-</samp>’ is the first argument, and the directory change is
successful, the absolute pathname of the new working directory is
written to the standard output.
</p>
-<p>If the directory change is successful, <code>cd</code> sets the value of the
-<code>PWD</code> environment variable to the new directory name, and sets the
-<code>OLDPWD</code> environment variable to the value of the current working
+<p>If the directory change is successful, <code class="code">cd</code> sets the value of the
+<code class="env">PWD</code> environment variable to the new directory name, and sets the
+<code class="env">OLDPWD</code> environment variable to the value of the current working
directory before the change.
</p>
<p>The return status is zero if the directory is successfully changed,
non-zero otherwise.
</p>
</dd>
-<dt id='index-continue'><span><code>continue</code><a href='#index-continue' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-continue"></a><span><code class="code">continue</code><a class="copiable-link" href="#index-continue"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">continue [<var>n</var>]
+<pre class="example-preformatted">continue [<var class="var">n</var>]
</pre></div>
-<p>Resume the next iteration of an enclosing <code>for</code>, <code>while</code>,
-<code>until</code>, or <code>select</code> loop.
-If <var>n</var> is supplied, the execution of the <var>n</var>th enclosing loop
+<p>Resume the next iteration of an enclosing <code class="code">for</code>, <code class="code">while</code>,
+<code class="code">until</code>, or <code class="code">select</code> loop.
+If <var class="var">n</var> is supplied, the execution of the <var class="var">n</var>th enclosing loop
is resumed.
-<var>n</var> must be greater than or equal to 1.
-The return status is zero unless <var>n</var> is not greater than or equal to 1.
+<var class="var">n</var> must be greater than or equal to 1.
+The return status is zero unless <var class="var">n</var> is not greater than or equal to 1.
</p>
</dd>
-<dt id='index-eval'><span><code>eval</code><a href='#index-eval' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-eval"></a><span><code class="code">eval</code><a class="copiable-link" href="#index-eval"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">eval [<var>arguments</var>]
+<pre class="example-preformatted">eval [<var class="var">arguments</var>]
</pre></div>
<p>The arguments are concatenated together into a single command, which is
then read and executed, and its exit status returned as the exit status
-of <code>eval</code>.
+of <code class="code">eval</code>.
If there are no arguments or only empty arguments, the return status is
zero.
</p>
</dd>
-<dt id='index-exec'><span><code>exec</code><a href='#index-exec' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-exec"></a><span><code class="code">exec</code><a class="copiable-link" href="#index-exec"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">exec [-cl] [-a <var>name</var>] [<var>command</var> [<var>arguments</var>]]
+<pre class="example-preformatted">exec [-cl] [-a <var class="var">name</var>] [<var class="var">command</var> [<var class="var">arguments</var>]]
</pre></div>
-<p>If <var>command</var>
+<p>If <var class="var">command</var>
is supplied, it replaces the shell without creating a new process.
-If the <samp>-l</samp> option is supplied, the shell places a dash at the
-beginning of the zeroth argument passed to <var>command</var>.
-This is what the <code>login</code> program does.
-The <samp>-c</samp> option causes <var>command</var> to be executed with an empty
+If the <samp class="option">-l</samp> option is supplied, the shell places a dash at the
+beginning of the zeroth argument passed to <var class="var">command</var>.
+This is what the <code class="code">login</code> program does.
+The <samp class="option">-c</samp> option causes <var class="var">command</var> to be executed with an empty
environment.
-If <samp>-a</samp> is supplied, the shell passes <var>name</var> as the zeroth
-argument to <var>command</var>.
-If <var>command</var>
+If <samp class="option">-a</samp> is supplied, the shell passes <var class="var">name</var> as the zeroth
+argument to <var class="var">command</var>.
+If <var class="var">command</var>
cannot be executed for some reason, a non-interactive shell exits,
-unless the <code>execfail</code> shell option
+unless the <code class="code">execfail</code> shell option
is enabled. In that case, it returns failure.
An interactive shell returns failure if the file cannot be executed.
-A subshell exits unconditionally if <code>exec</code> fails.
-If no <var>command</var> is specified, redirections may be used to affect
+A subshell exits unconditionally if <code class="code">exec</code> fails.
+If no <var class="var">command</var> is specified, redirections may be used to affect
the current shell environment. If there are no redirection errors, the
return status is zero; otherwise the return status is non-zero.
</p>
</dd>
-<dt id='index-exit'><span><code>exit</code><a href='#index-exit' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-exit"></a><span><code class="code">exit</code><a class="copiable-link" href="#index-exit"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">exit [<var>n</var>]
+<pre class="example-preformatted">exit [<var class="var">n</var>]
</pre></div>
-<p>Exit the shell, returning a status of <var>n</var> to the shell’s parent.
-If <var>n</var> is omitted, the exit status is that of the last command executed.
-Any trap on <code>EXIT</code> is executed before the shell terminates.
+<p>Exit the shell, returning a status of <var class="var">n</var> to the shell’s parent.
+If <var class="var">n</var> is omitted, the exit status is that of the last command executed.
+Any trap on <code class="code">EXIT</code> is executed before the shell terminates.
</p>
</dd>
-<dt id='index-export'><span><code>export</code><a href='#index-export' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-export"></a><span><code class="code">export</code><a class="copiable-link" href="#index-export"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">export [-fn] [-p] [<var>name</var>[=<var>value</var>]]
+<pre class="example-preformatted">export [-fn] [-p] [<var class="var">name</var>[=<var class="var">value</var>]]
</pre></div>
-<p>Mark each <var>name</var> to be passed to child processes
-in the environment. If the <samp>-f</samp> option is supplied, the <var>name</var>s
+<p>Mark each <var class="var">name</var> to be passed to child processes
+in the environment. If the <samp class="option">-f</samp> option is supplied, the <var class="var">name</var>s
refer to shell functions; otherwise the names refer to shell variables.
-The <samp>-n</samp> option means to no longer mark each <var>name</var> for export.
-If no <var>name</var>s are supplied, or if the <samp>-p</samp> option is given, a
+The <samp class="option">-n</samp> option means to no longer mark each <var class="var">name</var> for export.
+If no <var class="var">name</var>s are supplied, or if the <samp class="option">-p</samp> option is given, a
list of names of all exported variables is displayed.
-The <samp>-p</samp> option displays output in a form that may be reused as input.
-If a variable name is followed by =<var>value</var>, the value of
-the variable is set to <var>value</var>.
+The <samp class="option">-p</samp> option displays output in a form that may be reused as input.
+If a variable name is followed by =<var class="var">value</var>, the value of
+the variable is set to <var class="var">value</var>.
</p>
<p>The return status is zero unless an invalid option is supplied, one of
-the names is not a valid shell variable name, or <samp>-f</samp> is supplied
+the names is not a valid shell variable name, or <samp class="option">-f</samp> is supplied
with a name that is not a shell function.
</p>
</dd>
-<dt id='index-false'><span><code>false</code><a href='#index-false' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-false"></a><span><code class="code">false</code><a class="copiable-link" href="#index-false"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">false
+<pre class="example-preformatted">false
</pre></div>
<p>Does nothing, returns a non-zero status.
</p>
</dd>
-<dt id='index-getopts'><span><code>getopts</code><a href='#index-getopts' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-getopts"></a><span><code class="code">getopts</code><a class="copiable-link" href="#index-getopts"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">getopts <var>optstring</var> <var>name</var> [<var>arg</var> …]
+<pre class="example-preformatted">getopts <var class="var">optstring</var> <var class="var">name</var> [<var class="var">arg</var> ...]
</pre></div>
-<p><code>getopts</code> is used by shell scripts to parse positional parameters.
-<var>optstring</var> contains the option characters to be recognized; if a
+<p><code class="code">getopts</code> is used by shell scripts to parse positional parameters.
+<var class="var">optstring</var> contains the option characters to be recognized; if a
character is followed by a colon, the option is expected to have an
argument, which should be separated from it by whitespace.
-The colon (‘<samp>:</samp>’) and question mark (‘<samp>?</samp>’) may not be
+The colon (‘<samp class="samp">:</samp>’) and question mark (‘<samp class="samp">?</samp>’) may not be
used as option characters.
-Each time it is invoked, <code>getopts</code>
-places the next option in the shell variable <var>name</var>, initializing
-<var>name</var> if it does not exist,
+Each time it is invoked, <code class="code">getopts</code>
+places the next option in the shell variable <var class="var">name</var>, initializing
+<var class="var">name</var> if it does not exist,
and the index of the next argument to be processed into the
-variable <code>OPTIND</code>.
-<code>OPTIND</code> is initialized to 1 each time the shell or a shell script
+variable <code class="env">OPTIND</code>.
+<code class="env">OPTIND</code> is initialized to 1 each time the shell or a shell script
is invoked.
When an option requires an argument,
-<code>getopts</code> places that argument into the variable <code>OPTARG</code>.
-The shell does not reset <code>OPTIND</code> automatically; it must be manually
-reset between multiple calls to <code>getopts</code> within the same shell
+<code class="code">getopts</code> places that argument into the variable <code class="env">OPTARG</code>.
+The shell does not reset <code class="env">OPTIND</code> automatically; it must be manually
+reset between multiple calls to <code class="code">getopts</code> within the same shell
invocation if a new set of parameters is to be used.
</p>
-<p>When the end of options is encountered, <code>getopts</code> exits with a
+<p>When the end of options is encountered, <code class="code">getopts</code> exits with a
return value greater than zero.
-<code>OPTIND</code> is set to the index of the first non-option argument,
-and <var>name</var> is set to ‘<samp>?</samp>’.
+<code class="env">OPTIND</code> is set to the index of the first non-option argument,
+and <var class="var">name</var> is set to ‘<samp class="samp">?</samp>’.
</p>
-<p><code>getopts</code>
+<p><code class="code">getopts</code>
normally parses the positional parameters, but if more arguments are
-supplied as <var>arg</var> values, <code>getopts</code> parses those instead.
+supplied as <var class="var">arg</var> values, <code class="code">getopts</code> parses those instead.
</p>
-<p><code>getopts</code> can report errors in two ways. If the first character of
-<var>optstring</var> is a colon, <var>silent</var>
+<p><code class="code">getopts</code> can report errors in two ways. If the first character of
+<var class="var">optstring</var> is a colon, <var class="var">silent</var>
error reporting is used. In normal operation, diagnostic messages
are printed when invalid options or missing option arguments are
encountered.
-If the variable <code>OPTERR</code>
+If the variable <code class="env">OPTERR</code>
is set to 0, no error messages will be displayed, even if the first
-character of <code>optstring</code> is not a colon.
+character of <code class="code">optstring</code> is not a colon.
</p>
-<p>If an invalid option is seen,
-<code>getopts</code> places ‘<samp>?</samp>’ into <var>name</var> and, if not silent,
-prints an error message and unsets <code>OPTARG</code>.
-If <code>getopts</code> is silent, the option character found is placed in
-<code>OPTARG</code> and no diagnostic message is printed.
+<p>If <code class="code">getopts</code> detects an invalid option, it
+places ‘<samp class="samp">?</samp>’ into <var class="var">name</var> and, if not silent,
+prints an error message and unsets <code class="env">OPTARG</code>.
+If <code class="code">getopts</code> is silent, it assigns the option character found
+to <code class="env">OPTARG</code> and does not print a diagnostic message.
</p>
-<p>If a required argument is not found, and <code>getopts</code>
-is not silent, a question mark (‘<samp>?</samp>’) is placed in <var>name</var>,
-<code>OPTARG</code> is unset, and a diagnostic message is printed.
-If <code>getopts</code> is silent, then a colon (‘<samp>:</samp>’) is placed in
-<var>name</var> and <code>OPTARG</code> is set to the option character found.
+<p>If a required argument is not found,
+and <code class="code">getopts</code> is not silent,
+it sets the value of <var class="var">name</var> to a question mark (‘<samp class="samp">?</samp>’),
+unsets <code class="code">OPTARG</code>, and prints a diagnostic message.
+If <code class="code">getopts</code> is silent,
+it sets the value of <var class="var">name</var> to a colon (‘<samp class="samp">:</samp>’),
+and sets <code class="env">OPTARG</code> to the option character found.
</p>
</dd>
-<dt id='index-hash'><span><code>hash</code><a href='#index-hash' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-hash"></a><span><code class="code">hash</code><a class="copiable-link" href="#index-hash"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">hash [-r] [-p <var>filename</var>] [-dt] [<var>name</var>]
+<pre class="example-preformatted">hash [-r] [-p <var class="var">filename</var>] [-dt] [<var class="var">name</var>]
</pre></div>
-<p>Each time <code>hash</code> is invoked, it remembers the full filenames of the
-commands specified as <var>name</var> arguments,
+<p>Each time <code class="code">hash</code> is invoked, it remembers the full filenames of the
+commands specified as <var class="var">name</var> arguments,
so they need not be searched for on subsequent invocations.
The commands are found by searching through the directories listed in
-<code>$PATH</code>.
+<code class="env">$PATH</code>.
Any previously-remembered filename is discarded.
-The <samp>-p</samp> option inhibits the path search, and <var>filename</var> is
-used as the location of <var>name</var>.
-The <samp>-r</samp> option causes the shell to forget all remembered locations.
-Assigning to the <code>PATH</code> variable also clears all hashed filenames.
-The <samp>-d</samp> option causes the shell to forget the remembered location
-of each <var>name</var>.
-If the <samp>-t</samp> option is supplied, the full pathname to which each
-<var>name</var> corresponds is printed. If multiple <var>name</var> arguments are
-supplied with <samp>-t</samp>, the <var>name</var> is printed before the hashed
+The <samp class="option">-p</samp> option inhibits the path search, and <var class="var">filename</var> is
+used as the location of <var class="var">name</var>.
+The <samp class="option">-r</samp> option causes the shell to forget all remembered locations.
+Assigning to the <code class="env">PATH</code> variable also clears all hashed filenames.
+The <samp class="option">-d</samp> option causes the shell to forget the remembered location
+of each <var class="var">name</var>.
+If the <samp class="option">-t</samp> option is supplied, the full pathname to which each
+<var class="var">name</var> corresponds is printed. If multiple <var class="var">name</var> arguments are
+supplied with <samp class="option">-t</samp>, the <var class="var">name</var> is printed before the hashed
full pathname.
-The <samp>-l</samp> option causes output to be displayed in a format
+The <samp class="option">-l</samp> option causes output to be displayed in a format
that may be reused as input.
-If no arguments are given, or if only <samp>-l</samp> is supplied,
+If no arguments are given, or if only <samp class="option">-l</samp> is supplied,
information about remembered commands is printed.
-The <samp>-t</samp>, <samp>-d</samp>, and <samp>-p</samp> options (the options that
-act on the <var>name</var> arguments) are mutually exclusive.
+The <samp class="option">-t</samp>, <samp class="option">-d</samp>, and <samp class="option">-p</samp> options (the options that
+act on the <var class="var">name</var> arguments) are mutually exclusive.
Only one will be active.
-If more than one is supplied, <samp>-t</samp> has higher priority than
-<samp>-p</samp>, and both are higher priority than <samp>-d</samp>.
-The return status is zero unless a <var>name</var> is not found or an invalid
+If more than one is supplied, <samp class="option">-t</samp> has higher priority than
+<samp class="option">-p</samp>, and both are higher priority than <samp class="option">-d</samp>.
+The return status is zero unless a <var class="var">name</var> is not found or an invalid
option is supplied.
</p>
</dd>
-<dt id='index-pwd'><span><code>pwd</code><a href='#index-pwd' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-pwd"></a><span><code class="code">pwd</code><a class="copiable-link" href="#index-pwd"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">pwd [-LP]
+<pre class="example-preformatted">pwd [-LP]
</pre></div>
<p>Print the absolute pathname of the current working directory.
-If the <samp>-P</samp> option is supplied, the pathname printed will not
+If the <samp class="option">-P</samp> option is supplied, the pathname printed will not
contain symbolic links.
-If the <samp>-L</samp> option is supplied, the pathname printed may contain
+If the <samp class="option">-L</samp> option is supplied, the pathname printed may contain
symbolic links.
The return status is zero unless an error is encountered while
determining the name of the current directory or an invalid option
is supplied.
</p>
</dd>
-<dt id='index-readonly'><span><code>readonly</code><a href='#index-readonly' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-readonly"></a><span><code class="code">readonly</code><a class="copiable-link" href="#index-readonly"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">readonly [-aAf] [-p] [<var>name</var>[=<var>value</var>]] …
+<pre class="example-preformatted">readonly [-aAf] [-p] [<var class="var">name</var>[=<var class="var">value</var>]] ...
</pre></div>
-<p>Mark each <var>name</var> as readonly.
+<p>Mark each <var class="var">name</var> as readonly.
The values of these names may not be changed by subsequent assignment.
-If the <samp>-f</samp> option is supplied, each <var>name</var> refers to a shell
+If the <samp class="option">-f</samp> option is supplied, each <var class="var">name</var> refers to a shell
function.
-The <samp>-a</samp> option means each <var>name</var> refers to an indexed
-array variable; the <samp>-A</samp> option means each <var>name</var> refers
+The <samp class="option">-a</samp> option means each <var class="var">name</var> refers to an indexed
+array variable; the <samp class="option">-A</samp> option means each <var class="var">name</var> refers
to an associative array variable.
-If both options are supplied, <samp>-A</samp> takes precedence.
-If no <var>name</var> arguments are given, or if the <samp>-p</samp>
+If both options are supplied, <samp class="option">-A</samp> takes precedence.
+If no <var class="var">name</var> arguments are given, or if the <samp class="option">-p</samp>
option is supplied, a list of all readonly names is printed.
The other options may be used to restrict the output to a subset of
the set of readonly names.
-The <samp>-p</samp> option causes output to be displayed in a format that
+The <samp class="option">-p</samp> option causes output to be displayed in a format that
may be reused as input.
-If a variable name is followed by =<var>value</var>, the value of
-the variable is set to <var>value</var>.
+If a variable name is followed by =<var class="var">value</var>, the value of
+the variable is set to <var class="var">value</var>.
The return status is zero unless an invalid option is supplied, one of
-the <var>name</var> arguments is not a valid shell variable or function name,
-or the <samp>-f</samp> option is supplied with a name that is not a shell function.
+the <var class="var">name</var> arguments is not a valid shell variable or function name,
+or the <samp class="option">-f</samp> option is supplied with a name that is not a shell function.
</p>
</dd>
-<dt id='index-return'><span><code>return</code><a href='#index-return' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-return"></a><span><code class="code">return</code><a class="copiable-link" href="#index-return"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">return [<var>n</var>]
+<pre class="example-preformatted">return [<var class="var">n</var>]
</pre></div>
-<p>Cause a shell function to stop executing and return the value <var>n</var>
+<p>Cause a shell function to stop executing and return the value <var class="var">n</var>
to its caller.
-If <var>n</var> is not supplied, the return value is the exit status of the
+If <var class="var">n</var> is not supplied, the return value is the exit status of the
last command executed in the function.
-If <code>return</code> is executed by a trap handler, the last command used to
+If <code class="code">return</code> is executed by a trap handler, the last command used to
determine the status is the last command executed before the trap handler.
-If <code>return</code> is executed during a <code>DEBUG</code> trap, the last command
+If <code class="code">return</code> is executed during a <code class="code">DEBUG</code> trap, the last command
used to determine the status is the last command executed by the trap
-handler before <code>return</code> was invoked.
-<code>return</code> may also be used to terminate execution of a script
-being executed with the <code>.</code> (<code>source</code>) builtin,
-returning either <var>n</var> or
+handler before <code class="code">return</code> was invoked.
+<code class="code">return</code> may also be used to terminate execution of a script
+being executed with the <code class="code">.</code> (<code class="code">source</code>) builtin,
+returning either <var class="var">n</var> or
the exit status of the last command executed within the script as the exit
status of the script.
-If <var>n</var> is supplied, the return value is its least significant
+If <var class="var">n</var> is supplied, the return value is its least significant
8 bits.
-Any command associated with the <code>RETURN</code> trap is executed
+Any command associated with the <code class="code">RETURN</code> trap is executed
before execution resumes after the function or script.
-The return status is non-zero if <code>return</code> is supplied a non-numeric
+The return status is non-zero if <code class="code">return</code> is supplied a non-numeric
argument or is used outside a function
-and not during the execution of a script by <code>.</code> or <code>source</code>.
+and not during the execution of a script by <code class="code">.</code> or <code class="code">source</code>.
</p>
</dd>
-<dt id='index-shift'><span><code>shift</code><a href='#index-shift' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shift"></a><span><code class="code">shift</code><a class="copiable-link" href="#index-shift"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">shift [<var>n</var>]
+<pre class="example-preformatted">shift [<var class="var">n</var>]
</pre></div>
-<p>Shift the positional parameters to the left by <var>n</var>.
-The positional parameters from <var>n</var>+1 … <code>$#</code> are
-renamed to <code>$1</code> … <code>$#</code>-<var>n</var>.
-Parameters represented by the numbers <code>$#</code> down to <code>$#</code>-<var>n</var>+1
+<p>Shift the positional parameters to the left by <var class="var">n</var>.
+The positional parameters from <var class="var">n</var>+1 … <code class="code">$#</code> are
+renamed to <code class="code">$1</code> … <code class="code">$#</code>-<var class="var">n</var>.
+Parameters represented by the numbers <code class="code">$#</code> down to <code class="code">$#</code>-<var class="var">n</var>+1
are unset.
-<var>n</var> must be a non-negative number less than or equal to <code>$#</code>.
-If <var>n</var> is zero or greater than <code>$#</code>, the positional parameters
+<var class="var">n</var> must be a non-negative number less than or equal to <code class="code">$#</code>.
+If <var class="var">n</var> is zero or greater than <code class="code">$#</code>, the positional parameters
are not changed.
-If <var>n</var> is not supplied, it is assumed to be 1.
-The return status is zero unless <var>n</var> is greater than <code>$#</code> or
+If <var class="var">n</var> is not supplied, it is assumed to be 1.
+The return status is zero unless <var class="var">n</var> is greater than <code class="code">$#</code> or
less than zero, non-zero otherwise.
</p>
</dd>
-<dt id='index-test'><span><code>test</code><a href='#index-test' class='copiable-anchor'> ¶</a></span></dt>
-<dt><span><code>[</code></span></dt>
-<dd><span id="index-_005b"></span>
-<div class="example">
-<pre class="example">test <var>expr</var>
+<dt><a class="index-entry-id" id="index-_005b"></a>
+<a id="index-test"></a><span><code class="code">test</code><a class="copiable-link" href="#index-test"> ¶</a></span></dt>
+<dt><code class="code">[</code></dt>
+<dd><div class="example">
+<pre class="example-preformatted">test <var class="var">expr</var>
</pre></div>
-<p>Evaluate a conditional expression <var>expr</var> and return a status of 0
+<p>Evaluate a conditional expression <var class="var">expr</var> and return a status of 0
(true) or 1 (false).
Each operator and operand must be a separate argument.
Expressions are composed of the primaries described below in
-<a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>.
-<code>test</code> does not accept any options, nor does it accept and ignore
-an argument of <samp>--</samp> as signifying the end of options.
+<a class="ref" href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>.
+<code class="code">test</code> does not accept any options, nor does it accept and ignore
+an argument of <samp class="option">--</samp> as signifying the end of options.
</p>
-<p>When the <code>[</code> form is used, the last argument to the command must
-be a <code>]</code>.
+<p>When the <code class="code">[</code> form is used, the last argument to the command must
+be a <code class="code">]</code>.
</p>
<p>Expressions may be combined using the following operators, listed in
decreasing order of precedence.
The evaluation depends on the number of arguments; see below.
Operator precedence is used when there are five or more arguments.
</p>
-<dl compact="compact">
-<dt><span><code>! <var>expr</var></code></span></dt>
-<dd><p>True if <var>expr</var> is false.
+<dl class="table">
+<dt><code class="code">! <var class="var">expr</var></code></dt>
+<dd><p>True if <var class="var">expr</var> is false.
</p>
</dd>
-<dt><span><code>( <var>expr</var> )</code></span></dt>
-<dd><p>Returns the value of <var>expr</var>.
+<dt><code class="code">( <var class="var">expr</var> )</code></dt>
+<dd><p>Returns the value of <var class="var">expr</var>.
This may be used to override the normal precedence of operators.
</p>
</dd>
-<dt><span><code><var>expr1</var> -a <var>expr2</var></code></span></dt>
-<dd><p>True if both <var>expr1</var> and <var>expr2</var> are true.
+<dt><code class="code"><var class="var">expr1</var> -a <var class="var">expr2</var></code></dt>
+<dd><p>True if both <var class="var">expr1</var> and <var class="var">expr2</var> are true.
</p>
</dd>
-<dt><span><code><var>expr1</var> -o <var>expr2</var></code></span></dt>
-<dd><p>True if either <var>expr1</var> or <var>expr2</var> is true.
+<dt><code class="code"><var class="var">expr1</var> -o <var class="var">expr2</var></code></dt>
+<dd><p>True if either <var class="var">expr1</var> or <var class="var">expr2</var> is true.
</p></dd>
</dl>
-<p>The <code>test</code> and <code>[</code> builtins evaluate conditional
+<p>The <code class="code">test</code> and <code class="code">[</code> builtins evaluate conditional
expressions using a set of rules based on the number of arguments.
</p>
-<dl compact="compact">
-<dt><span>0 arguments</span></dt>
+<dl class="table">
+<dt>0 arguments</dt>
<dd><p>The expression is false.
</p>
</dd>
-<dt><span>1 argument</span></dt>
+<dt>1 argument</dt>
<dd><p>The expression is true if, and only if, the argument is not null.
</p>
</dd>
-<dt><span>2 arguments</span></dt>
-<dd><p>If the first argument is ‘<samp>!</samp>’, the expression is true if and
+<dt>2 arguments</dt>
+<dd><p>If the first argument is ‘<samp class="samp">!</samp>’, the expression is true if and
only if the second argument is null.
If the first argument is one of the unary conditional operators
-(see <a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>), the expression
+(see <a class="pxref" href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>), the expression
is true if the unary test is true.
If the first argument is not a valid unary operator, the expression is
false.
</p>
</dd>
-<dt><span>3 arguments</span></dt>
+<dt>3 arguments</dt>
<dd><p>The following conditions are applied in the order listed.
</p>
-<ol>
+<ol class="enumerate">
<li> If the second argument is one of the binary conditional
-operators (see <a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>), the
+operators (see <a class="pxref" href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>), the
result of the expression is the result of the binary test using the
first and third arguments as operands.
-The ‘<samp>-a</samp>’ and ‘<samp>-o</samp>’ operators are considered binary operators
+The ‘<samp class="samp">-a</samp>’ and ‘<samp class="samp">-o</samp>’ operators are considered binary operators
when there are three arguments.
-</li><li> If the first argument is ‘<samp>!</samp>’, the value is the negation of
+</li><li> If the first argument is ‘<samp class="samp">!</samp>’, the value is the negation of
the two-argument test using the second and third arguments.
-</li><li> If the first argument is exactly ‘<samp>(</samp>’ and the third argument is
-exactly ‘<samp>)</samp>’, the result is the one-argument test of the second
+</li><li> If the first argument is exactly ‘<samp class="samp">(</samp>’ and the third argument is
+exactly ‘<samp class="samp">)</samp>’, the result is the one-argument test of the second
argument.
</li><li> Otherwise, the expression is false.
</li></ol>
</dd>
-<dt><span>4 arguments</span></dt>
+<dt>4 arguments</dt>
<dd><p>The following conditions are applied in the order listed.
</p>
-<ol>
-<li> If the first argument is ‘<samp>!</samp>’, the result is the negation of
+<ol class="enumerate">
+<li> If the first argument is ‘<samp class="samp">!</samp>’, the result is the negation of
the three-argument expression composed of the remaining arguments.
-</li><li> If the first argument is exactly ‘<samp>(</samp>’ and the fourth argument is
-exactly ‘<samp>)</samp>’, the result is the two-argument test of the second
+</li><li> If the first argument is exactly ‘<samp class="samp">(</samp>’ and the fourth argument is
+exactly ‘<samp class="samp">)</samp>’, the result is the two-argument test of the second
and third arguments.
</li><li> Otherwise, the expression is parsed and evaluated according to
precedence using the rules listed above.
</li></ol>
</dd>
-<dt><span>5 or more arguments</span></dt>
+<dt>5 or more arguments</dt>
<dd><p>The expression is parsed and evaluated according to precedence
using the rules listed above.
</p></dd>
</dl>
-<p>If the shell is not in <small>POSIX</small> mode,
-when used with <code>test</code> or ‘<samp>[</samp>’, the ‘<samp><</samp>’ and ‘<samp>></samp>’
-operators sort lexicographically using ASCII ordering.
-If the shell is in <small>POSIX</small> mode, these operators use the current locale.
+<p>If the shell is in <small class="sc">POSIX</small> mode, or if the expression is part
+of the <code class="code">[[</code> command,
+the ‘<samp class="samp"><</samp>’ and ‘<samp class="samp">></samp>’ operators sort using the current locale.
+If the shell is not in <small class="sc">POSIX</small> mode,
+the <code class="code">test</code> and ‘<samp class="samp">[</samp>’ commands
+sort lexicographically using ASCII ordering.
</p>
<p>The historical operator-precedence parsing with 4 or more arguments can
lead to ambiguities when it encounters strings that look like primaries.
-The <small>POSIX</small> standard has deprecated the <samp>-a</samp> and <samp>-o</samp>
+The <small class="sc">POSIX</small> standard has deprecated the <samp class="option">-a</samp> and <samp class="option">-o</samp>
primaries and enclosing expressions within parentheses.
Scripts should no longer use them.
It’s much more reliable to restrict test invocations to a single primary,
-and to replace uses of <samp>-a</samp> and <samp>-o</samp> with the shell’s
-<code>&&</code> and <code>||</code> list operators. For example, use
+and to replace uses of <samp class="option">-a</samp> and <samp class="option">-o</samp> with the shell’s
+<code class="code">&&</code> and <code class="code">||</code> list operators. For example, use
</p>
<div class="example">
-<pre class="example">test -n string1 && test -n string2
+<pre class="example-preformatted">test -n string1 && test -n string2
</pre></div>
<p>instead of
</p>
<div class="example">
-<pre class="example">test -n string1 -a -n string2
+<pre class="example-preformatted">test -n string1 -a -n string2
</pre></div>
</dd>
-<dt id='index-times'><span><code>times</code><a href='#index-times' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-times"></a><span><code class="code">times</code><a class="copiable-link" href="#index-times"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">times
+<pre class="example-preformatted">times
</pre></div>
<p>Print out the user and system times used by the shell and its children.
The return status is zero.
</p>
</dd>
-<dt id='index-trap'><span><code>trap</code><a href='#index-trap' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-trap"></a><span><code class="code">trap</code><a class="copiable-link" href="#index-trap"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">trap [-Plp] [<var>action</var>] [<var>sigspec</var> …]
+<pre class="example-preformatted">trap [-Plp] [<var class="var">action</var>] [<var class="var">sigspec</var> ...]
</pre></div>
-<p>The <var>action</var> is a command that is read and executed when the
-shell receives signal <var>sigspec</var>. If <var>action</var> is absent (and
-there is a single <var>sigspec</var>) or
-equal to ‘<samp>-</samp>’, each specified signal’s disposition is reset
+<p>The <var class="var">action</var> is a command that is read and executed when the
+shell receives signal <var class="var">sigspec</var>. If <var class="var">action</var> is absent (and
+there is a single <var class="var">sigspec</var>) or
+equal to ‘<samp class="samp">-</samp>’, each specified signal’s disposition is reset
to the value it had when the shell was started.
-If <var>action</var> is the null string, then the signal specified by
-each <var>sigspec</var> is ignored by the shell and commands it invokes.
+If <var class="var">action</var> is the null string, then the signal specified by
+each <var class="var">sigspec</var> is ignored by the shell and commands it invokes.
</p>
-<p>If no arguments are supplied, <code>trap</code> prints the actions
+<p>If no arguments are supplied, <code class="code">trap</code> prints the actions
associated with each trapped signal
-as a set of <code>trap</code> commands that can be reused as shell input to
+as a set of <code class="code">trap</code> commands that can be reused as shell input to
restore the current signal dispositions.
-If <var>action</var> is not present and <samp>-p</samp> has been supplied,
-<code>trap</code> displays the trap commands associated with each <var>sigspec</var>,
-or, if no <var>sigspec</var>s are supplied, for all trapped signals,
-as a set of <code>trap</code> commands that can be reused as shell input to
+If <var class="var">action</var> is not present and <samp class="option">-p</samp> has been supplied,
+<code class="code">trap</code> displays the trap commands associated with each <var class="var">sigspec</var>,
+or, if no <var class="var">sigspec</var>s are supplied, for all trapped signals,
+as a set of <code class="code">trap</code> commands that can be reused as shell input to
restore the current signal dispositions.
-The <samp>-P</samp> option behaves similarly, but displays only the actions
-associated with each <var>sigspec</var> argument.
-<samp>-P</samp> requires at least one <var>sigspec</var> argument.
-The <samp>-P</samp> or <samp>-p</samp> options to <code>trap</code> may be
+The <samp class="option">-P</samp> option behaves similarly, but displays only the actions
+associated with each <var class="var">sigspec</var> argument.
+<samp class="option">-P</samp> requires at least one <var class="var">sigspec</var> argument.
+The <samp class="option">-P</samp> or <samp class="option">-p</samp> options to <code class="code">trap</code> may be
used in a subshell environment (e.g., command substitution) and,
-as long as they are used before <code>trap</code> is used to change a
+as long as they are used before <code class="code">trap</code> is used to change a
signal’s handling, will display the state of its parent’s traps.
</p>
-<p>The <samp>-l</samp> option causes <code>trap</code> to print a list of signal names
+<p>The <samp class="option">-l</samp> option causes <code class="code">trap</code> to print a list of signal names
and their corresponding numbers.
-Each <var>sigspec</var> is either a signal name or a signal number.
-Signal names are case insensitive and the <code>SIG</code> prefix is optional.
-</p>
-<p>If a <var>sigspec</var>
-is <code>0</code> or <code>EXIT</code>, <var>action</var> is executed when the shell exits.
-If a <var>sigspec</var> is <code>DEBUG</code>, <var>action</var> is executed
-before every simple command, <code>for</code> command, <code>case</code> command,
-<code>select</code> command, (( arithmetic command, [[ conditional command,
-arithmetic <code>for</code> command,
+Each <var class="var">sigspec</var> is either a signal name or a signal number.
+Signal names are case insensitive and the <code class="code">SIG</code> prefix is optional.
+</p>
+<p>If a <var class="var">sigspec</var>
+is <code class="code">0</code> or <code class="code">EXIT</code>, <var class="var">action</var> is executed when the shell exits.
+If a <var class="var">sigspec</var> is <code class="code">DEBUG</code>, <var class="var">action</var> is executed
+before every simple command, <code class="code">for</code> command, <code class="code">case</code> command,
+<code class="code">select</code> command, (( arithmetic command, [[ conditional command,
+arithmetic <code class="code">for</code> command,
and before the first command executes in a shell function.
-Refer to the description of the <code>extdebug</code> option to the
-<code>shopt</code> builtin (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>) for details of its
-effect on the <code>DEBUG</code> trap.
-If a <var>sigspec</var> is <code>RETURN</code>, <var>action</var> is executed
-each time a shell function or a script executed with the <code>.</code> or
-<code>source</code> builtins finishes executing.
-</p>
-<p>If a <var>sigspec</var> is <code>ERR</code>, <var>action</var>
+Refer to the description of the <code class="code">extdebug</code> option to the
+<code class="code">shopt</code> builtin (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>) for details of its
+effect on the <code class="code">DEBUG</code> trap.
+If a <var class="var">sigspec</var> is <code class="code">RETURN</code>, <var class="var">action</var> is executed
+each time a shell function or a script executed with the <code class="code">.</code> or
+<code class="code">source</code> builtins finishes executing.
+</p>
+<p>If a <var class="var">sigspec</var> is <code class="code">ERR</code>, <var class="var">action</var>
is executed whenever
a pipeline (which may consist of a single simple
command), a list, or a compound command returns a
non-zero exit status,
subject to the following conditions.
-The <code>ERR</code> trap is not executed if the failed command is part of the
-command list immediately following an <code>until</code> or <code>while</code> keyword,
-part of the test following the <code>if</code> or <code>elif</code> reserved words,
-part of a command executed in a <code>&&</code> or <code>||</code> list
-except the command following the final <code>&&</code> or <code>||</code>,
+The <code class="code">ERR</code> trap is not executed if the failed command is part of the
+command list immediately following an <code class="code">until</code> or <code class="code">while</code> keyword,
+part of the test following the <code class="code">if</code> or <code class="code">elif</code> reserved words,
+part of a command executed in a <code class="code">&&</code> or <code class="code">||</code> list
+except the command following the final <code class="code">&&</code> or <code class="code">||</code>,
any command in a pipeline but the last,
or if the command’s return
-status is being inverted using <code>!</code>.
-These are the same conditions obeyed by the <code>errexit</code> (<samp>-e</samp>)
+status is being inverted using <code class="code">!</code>.
+These are the same conditions obeyed by the <code class="code">errexit</code> (<samp class="option">-e</samp>)
option.
</p>
<p>Signals ignored upon entry to a non-interactive shell cannot be trapped or
Trapped signals that are not being ignored are reset to their original
values in a subshell or subshell environment when one is created.
</p>
-<p>The return status is zero unless a <var>sigspec</var> does not specify a
+<p>The return status is zero unless a <var class="var">sigspec</var> does not specify a
valid signal.
</p>
</dd>
-<dt id='index-true'><span><code>true</code><a href='#index-true' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-true"></a><span><code class="code">true</code><a class="copiable-link" href="#index-true"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">true
+<pre class="example-preformatted">true
</pre></div>
<p>Does nothing, returns a 0 status.
</p>
</dd>
-<dt id='index-umask'><span><code>umask</code><a href='#index-umask' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-umask"></a><span><code class="code">umask</code><a class="copiable-link" href="#index-umask"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">umask [-p] [-S] [<var>mode</var>]
+<pre class="example-preformatted">umask [-p] [-S] [<var class="var">mode</var>]
</pre></div>
-<p>Set the shell process’s file creation mask to <var>mode</var>. If
-<var>mode</var> begins with a digit, it is interpreted as an octal number;
+<p>Set the shell process’s file creation mask to <var class="var">mode</var>. If
+<var class="var">mode</var> begins with a digit, it is interpreted as an octal number;
if not, it is interpreted as a symbolic mode mask similar
-to that accepted by the <code>chmod</code> command. If <var>mode</var> is
-omitted, the current value of the mask is printed. If the <samp>-S</samp>
-option is supplied without a <var>mode</var> argument, the mask is printed
+to that accepted by the <code class="code">chmod</code> command. If <var class="var">mode</var> is
+omitted, the current value of the mask is printed. If the <samp class="option">-S</samp>
+option is supplied without a <var class="var">mode</var> argument, the mask is printed
in a symbolic format.
-If the <samp>-p</samp> option is supplied, and <var>mode</var>
+If the <samp class="option">-p</samp> option is supplied, and <var class="var">mode</var>
is omitted, the output is in a form that may be reused as input.
The return status is zero if the mode is successfully changed or if
-no <var>mode</var> argument is supplied, and non-zero otherwise.
+no <var class="var">mode</var> argument is supplied, and non-zero otherwise.
</p>
<p>Note that when the mode is interpreted as an octal number, each number
-of the umask is subtracted from <code>7</code>. Thus, a umask of <code>022</code>
-results in permissions of <code>755</code>.
+of the umask is subtracted from <code class="code">7</code>. Thus, a umask of <code class="code">022</code>
+results in permissions of <code class="code">755</code>.
</p>
</dd>
-<dt id='index-unset'><span><code>unset</code><a href='#index-unset' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-unset"></a><span><code class="code">unset</code><a class="copiable-link" href="#index-unset"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">unset [-fnv] [<var>name</var>]
+<pre class="example-preformatted">unset [-fnv] [<var class="var">name</var>]
</pre></div>
-<p>Remove each variable or function <var>name</var>.
-If the <samp>-v</samp> option is given, each
-<var>name</var> refers to a shell variable and that variable is removed.
-If the <samp>-f</samp> option is given, the <var>name</var>s refer to shell
+<p>Remove each variable or function <var class="var">name</var>.
+If the <samp class="option">-v</samp> option is given, each
+<var class="var">name</var> refers to a shell variable and that variable is removed.
+If the <samp class="option">-f</samp> option is given, the <var class="var">name</var>s refer to shell
functions, and the function definition is removed.
-If the <samp>-n</samp> option is supplied, and <var>name</var> is a variable with
-the <code>nameref</code> attribute, <var>name</var> will be unset rather than the
+If the <samp class="option">-n</samp> option is supplied, and <var class="var">name</var> is a variable with
+the <code class="code">nameref</code> attribute, <var class="var">name</var> will be unset rather than the
variable it references.
-<samp>-n</samp> has no effect if the <samp>-f</samp> option is supplied.
-If no options are supplied, each <var>name</var> refers to a variable; if
+<samp class="option">-n</samp> has no effect if the <samp class="option">-f</samp> option is supplied.
+If no options are supplied, each <var class="var">name</var> refers to a variable; if
there is no variable by that name, a function with that name, if any, is
unset.
Readonly variables and functions may not be unset.
Some shell variables lose their special behavior if they are unset; such
behavior is noted in the description of the individual variables.
-The return status is zero unless a <var>name</var> is readonly or may not be unset.
+The return status is zero unless a <var class="var">name</var> is readonly or may not be unset.
</p></dd>
</dl>
<hr>
</div>
-<div class="section" id="Bash-Builtins">
-<div class="header">
+<div class="section-level-extent" id="Bash-Builtins">
+<div class="nav-panel">
<p>
Next: <a href="#Modifying-Shell-Behavior" accesskey="n" rel="next">Modifying Shell Behavior</a>, Previous: <a href="#Bourne-Shell-Builtins" accesskey="p" rel="prev">Bourne Shell Builtins</a>, Up: <a href="#Shell-Builtin-Commands" accesskey="u" rel="up">Shell Builtin Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-Builtin-Commands"></span><h3 class="section">4.2 Bash Builtin Commands</h3>
+<h3 class="section" id="Bash-Builtin-Commands"><span>4.2 Bash Builtin Commands<a class="copiable-link" href="#Bash-Builtin-Commands"> ¶</a></span></h3>
<p>This section describes builtin commands which are unique to
or have been extended in Bash.
-Some of these commands are specified in the <small>POSIX</small> standard.
+Some of these commands are specified in the <small class="sc">POSIX</small> standard.
</p>
-<dl compact="compact">
-<dt id='index-alias'><span><code>alias</code><a href='#index-alias' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-alias"></a><span><code class="code">alias</code><a class="copiable-link" href="#index-alias"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">alias [-p] [<var>name</var>[=<var>value</var>] …]
+<pre class="example-preformatted">alias [-p] [<var class="var">name</var>[=<var class="var">value</var>] ...]
</pre></div>
-<p>Without arguments or with the <samp>-p</samp> option, <code>alias</code> prints
+<p>Without arguments or with the <samp class="option">-p</samp> option, <code class="code">alias</code> prints
the list of aliases on the standard output in a form that allows
them to be reused as input.
-If arguments are supplied, an alias is defined for each <var>name</var>
-whose <var>value</var> is given. If no <var>value</var> is given, the name
+If arguments are supplied, an alias is defined for each <var class="var">name</var>
+whose <var class="var">value</var> is given. If no <var class="var">value</var> is given, the name
and value of the alias is printed.
-Aliases are described in <a href="#Aliases">Aliases</a>.
+Aliases are described in <a class="ref" href="#Aliases">Aliases</a>.
</p>
</dd>
-<dt id='index-bind'><span><code>bind</code><a href='#index-bind' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-bind"></a><span><code class="code">bind</code><a class="copiable-link" href="#index-bind"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">bind [-m <var>keymap</var>] [-lpsvPSVX]
-bind [-m <var>keymap</var>] [-q <var>function</var>] [-u <var>function</var>] [-r <var>keyseq</var>]
-bind [-m <var>keymap</var>] -f <var>filename</var>
-bind [-m <var>keymap</var>] -x <var>keyseq[: ]shell-command</var>
-bind [-m <var>keymap</var>] <var>keyseq:function-name</var>
-bind [-m <var>keymap</var>] <var>keyseq:readline-command</var>
-bind <var>readline-command-line</var>
+<pre class="example-preformatted">bind [-m <var class="var">keymap</var>] [-lpsvPSVX]
+bind [-m <var class="var">keymap</var>] [-q <var class="var">function</var>] [-u <var class="var">function</var>] [-r <var class="var">keyseq</var>]
+bind [-m <var class="var">keymap</var>] -f <var class="var">filename</var>
+bind [-m <var class="var">keymap</var>] -x <var class="var">keyseq[: ]shell-command</var>
+bind [-m <var class="var">keymap</var>] <var class="var">keyseq:function-name</var>
+bind [-m <var class="var">keymap</var>] <var class="var">keyseq:readline-command</var>
+bind <var class="var">readline-command-line</var>
</pre></div>
-<p>Display current Readline (see <a href="#Command-Line-Editing">Command Line Editing</a>)
+<p>Display current Readline (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>)
key and function bindings,
bind a key sequence to a Readline function or macro,
or set a Readline variable.
Each non-option argument is a command as it would appear in a
-Readline initialization file (see <a href="#Readline-Init-File">Readline Init File</a>),
+Readline initialization file (see <a class="pxref" href="#Readline-Init-File">Readline Init File</a>),
but each binding or command must be passed as a separate argument; e.g.,
-‘<samp>"\C-x\C-r":re-read-init-file</samp>’.
+‘<samp class="samp">"\C-x\C-r":re-read-init-file</samp>’.
</p>
<p>Options, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-m <var>keymap</var></code></span></dt>
-<dd><p>Use <var>keymap</var> as the keymap to be affected by
-the subsequent bindings. Acceptable <var>keymap</var>
+<dl class="table">
+<dt><code class="code">-m <var class="var">keymap</var></code></dt>
+<dd><p>Use <var class="var">keymap</var> as the keymap to be affected by
+the subsequent bindings. Acceptable <var class="var">keymap</var>
names are
-<code>emacs</code>,
-<code>emacs-standard</code>,
-<code>emacs-meta</code>,
-<code>emacs-ctlx</code>,
-<code>vi</code>,
-<code>vi-move</code>,
-<code>vi-command</code>, and
-<code>vi-insert</code>.
-<code>vi</code> is equivalent to <code>vi-command</code> (<code>vi-move</code> is also a
-synonym); <code>emacs</code> is equivalent to <code>emacs-standard</code>.
-</p>
-</dd>
-<dt><span><code>-l</code></span></dt>
+<code class="code">emacs</code>,
+<code class="code">emacs-standard</code>,
+<code class="code">emacs-meta</code>,
+<code class="code">emacs-ctlx</code>,
+<code class="code">vi</code>,
+<code class="code">vi-move</code>,
+<code class="code">vi-command</code>, and
+<code class="code">vi-insert</code>.
+<code class="code">vi</code> is equivalent to <code class="code">vi-command</code> (<code class="code">vi-move</code> is also a
+synonym); <code class="code">emacs</code> is equivalent to <code class="code">emacs-standard</code>.
+</p>
+</dd>
+<dt><code class="code">-l</code></dt>
<dd><p>List the names of all Readline functions.
</p>
</dd>
-<dt><span><code>-p</code></span></dt>
+<dt><code class="code">-p</code></dt>
<dd><p>Display Readline function names and bindings
in such a way that they can be used as
-an argument to a subsequent <code>bind</code> command
+an argument to a subsequent <code class="code">bind</code> command
or in a Readline initialization file.
</p>
</dd>
-<dt><span><code>-P</code></span></dt>
+<dt><code class="code">-P</code></dt>
<dd><p>List current Readline function names and bindings.
</p>
</dd>
-<dt><span><code>-v</code></span></dt>
+<dt><code class="code">-v</code></dt>
<dd><p>Display Readline variable names and values
in such a way that they can be used as
-an argument to a subsequent <code>bind</code> command
+an argument to a subsequent <code class="code">bind</code> command
or in a Readline initialization file.
</p>
</dd>
-<dt><span><code>-V</code></span></dt>
+<dt><code class="code">-V</code></dt>
<dd><p>List current Readline variable names and values.
</p>
</dd>
-<dt><span><code>-s</code></span></dt>
+<dt><code class="code">-s</code></dt>
<dd><p>Display Readline key sequences bound to macros and the strings they output
in such a way that they can be used as
-an argument to a subsequent <code>bind</code> command
+an argument to a subsequent <code class="code">bind</code> command
or in a Readline initialization file.
</p>
</dd>
-<dt><span><code>-S</code></span></dt>
+<dt><code class="code">-S</code></dt>
<dd><p>Display Readline key sequences bound to macros and the strings they output.
</p>
</dd>
-<dt><span><code>-f <var>filename</var></code></span></dt>
-<dd><p>Read key bindings from <var>filename</var>.
+<dt><code class="code">-f <var class="var">filename</var></code></dt>
+<dd><p>Read key bindings from <var class="var">filename</var>.
</p>
</dd>
-<dt><span><code>-q <var>function</var></code></span></dt>
-<dd><p>Query about which keys invoke the named <var>function</var>.
+<dt><code class="code">-q <var class="var">function</var></code></dt>
+<dd><p>Query about which keys invoke the named <var class="var">function</var>.
</p>
</dd>
-<dt><span><code>-u <var>function</var></code></span></dt>
-<dd><p>Unbind all keys bound to the named <var>function</var>.
+<dt><code class="code">-u <var class="var">function</var></code></dt>
+<dd><p>Unbind all keys bound to the named <var class="var">function</var>.
</p>
</dd>
-<dt><span><code>-r <var>keyseq</var></code></span></dt>
-<dd><p>Remove any current binding for <var>keyseq</var>.
+<dt><code class="code">-r <var class="var">keyseq</var></code></dt>
+<dd><p>Remove any current binding for <var class="var">keyseq</var>.
</p>
</dd>
-<dt><span><code>-x <var>keyseq:shell-command</var></code></span></dt>
-<dd><p>Cause <var>shell-command</var> to be executed whenever <var>keyseq</var> is
+<dt><code class="code">-x <var class="var">keyseq:shell-command</var></code></dt>
+<dd><p>Cause <var class="var">shell-command</var> to be executed whenever <var class="var">keyseq</var> is
entered.
-The separator between <var>keyseq</var> and <var>shell-command</var> is either
+The separator between <var class="var">keyseq</var> and <var class="var">shell-command</var> is either
whitespace or a colon optionally followed by whitespace.
-If the separator is whitespace, <var>shell-command</var>
+If the separator is whitespace, <var class="var">shell-command</var>
must be enclosed in double quotes and Readline expands any of its
-special backslash-escapes in <var>shell-command</var> before saving it.
+special backslash-escapes in <var class="var">shell-command</var> before saving it.
If the separator is a colon, any enclosing double quotes are optional, and
Readline does not expand the command string before saving it.
Since the entire key binding expression must be a single argument, it
should be enclosed in quotes.
-When <var>shell-command</var> is executed, the shell sets the
-<code>READLINE_LINE</code> variable to the contents of the Readline line
-buffer and the <code>READLINE_POINT</code> and <code>READLINE_MARK</code> variables
+When <var class="var">shell-command</var> is executed, the shell sets the
+<code class="code">READLINE_LINE</code> variable to the contents of the Readline line
+buffer and the <code class="code">READLINE_POINT</code> and <code class="code">READLINE_MARK</code> variables
to the current location of the insertion point and the saved insertion
-point (the <var>mark</var>), respectively.
+point (the <var class="var">mark</var>), respectively.
The shell assigns any numeric argument the user supplied to the
-<code>READLINE_ARGUMENT</code> variable.
+<code class="code">READLINE_ARGUMENT</code> variable.
If there was no argument, that variable is not set.
-If the executed command changes the value of any of <code>READLINE_LINE</code>,
-<code>READLINE_POINT</code>, or <code>READLINE_MARK</code>, those new values will be
+If the executed command changes the value of any of <code class="code">READLINE_LINE</code>,
+<code class="code">READLINE_POINT</code>, or <code class="code">READLINE_MARK</code>, those new values will be
reflected in the editing state.
</p>
</dd>
-<dt><span><code>-X</code></span></dt>
+<dt><code class="code">-X</code></dt>
<dd><p>List all key sequences bound to shell commands and the associated commands
in a format that can be reused as
-an argument to a subsequent <code>bind</code> command.
+an argument to a subsequent <code class="code">bind</code> command.
</p></dd>
</dl>
error occurs.
</p>
</dd>
-<dt id='index-builtin'><span><code>builtin</code><a href='#index-builtin' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-builtin"></a><span><code class="code">builtin</code><a class="copiable-link" href="#index-builtin"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">builtin [<var>shell-builtin</var> [<var>args</var>]]
+<pre class="example-preformatted">builtin [<var class="var">shell-builtin</var> [<var class="var">args</var>]]
</pre></div>
-<p>Run a shell builtin, passing it <var>args</var>, and return its exit status.
+<p>Run a shell builtin, passing it <var class="var">args</var>, and return its exit status.
This is useful when defining a shell function with the same
name as a shell builtin, retaining the functionality of the builtin within
the function.
-The return status is non-zero if <var>shell-builtin</var> is not a shell
+The return status is non-zero if <var class="var">shell-builtin</var> is not a shell
builtin command.
</p>
</dd>
-<dt id='index-caller'><span><code>caller</code><a href='#index-caller' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-caller"></a><span><code class="code">caller</code><a class="copiable-link" href="#index-caller"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">caller [<var>expr</var>]
+<pre class="example-preformatted">caller [<var class="var">expr</var>]
</pre></div>
<p>Returns the context of any active subroutine call (a shell function or
-a script executed with the <code>.</code> or <code>source</code> builtins).
+a script executed with the <code class="code">.</code> or <code class="code">source</code> builtins).
</p>
-<p>Without <var>expr</var>, <code>caller</code> displays the line number and source
+<p>Without <var class="var">expr</var>, <code class="code">caller</code> displays the line number and source
filename of the current subroutine call.
-If a non-negative integer is supplied as <var>expr</var>, <code>caller</code>
+If a non-negative integer is supplied as <var class="var">expr</var>, <code class="code">caller</code>
displays the line number, subroutine name, and source file corresponding
to that position in the current execution call stack. This extra
information may be used, for example, to print a stack trace. The
current frame is frame 0.
</p>
<p>The return value is 0 unless the shell is not executing a subroutine
-call or <var>expr</var> does not correspond to a valid position in the
+call or <var class="var">expr</var> does not correspond to a valid position in the
call stack.
</p>
</dd>
-<dt id='index-command'><span><code>command</code><a href='#index-command' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-command"></a><span><code class="code">command</code><a class="copiable-link" href="#index-command"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">command [-pVv] <var>command</var> [<var>arguments</var> …]
+<pre class="example-preformatted">command [-pVv] <var class="var">command</var> [<var class="var">arguments</var> ...]
</pre></div>
-<p>Runs <var>command</var> with <var>arguments</var> ignoring any shell function
-named <var>command</var>.
+<p>Runs <var class="var">command</var> with <var class="var">arguments</var> ignoring any shell function
+named <var class="var">command</var>.
Only shell builtin commands or commands found by searching the
-<code>PATH</code> are executed.
-If there is a shell function named <code>ls</code>, running ‘<samp>command ls</samp>’
-within the function will execute the external command <code>ls</code>
+<code class="env">PATH</code> are executed.
+If there is a shell function named <code class="code">ls</code>, running ‘<samp class="samp">command ls</samp>’
+within the function will execute the external command <code class="code">ls</code>
instead of calling the function recursively.
-The <samp>-p</samp> option means to use a default value for <code>PATH</code>
+The <samp class="option">-p</samp> option means to use a default value for <code class="env">PATH</code>
that is guaranteed to find all of the standard utilities.
-The return status in this case is 127 if <var>command</var> cannot be
-found or an error occurred, and the exit status of <var>command</var>
+The return status in this case is 127 if <var class="var">command</var> cannot be
+found or an error occurred, and the exit status of <var class="var">command</var>
otherwise.
</p>
-<p>If either the <samp>-V</samp> or <samp>-v</samp> option is supplied, a
-description of <var>command</var> is printed. The <samp>-v</samp> option
+<p>If either the <samp class="option">-V</samp> or <samp class="option">-v</samp> option is supplied, a
+description of <var class="var">command</var> is printed. The <samp class="option">-v</samp> option
causes a single word indicating the command or file name used to
-invoke <var>command</var> to be displayed; the <samp>-V</samp> option produces
+invoke <var class="var">command</var> to be displayed; the <samp class="option">-V</samp> option produces
a more verbose description. In this case, the return status is
-zero if <var>command</var> is found, and non-zero if not.
+zero if <var class="var">command</var> is found, and non-zero if not.
</p>
</dd>
-<dt id='index-declare'><span><code>declare</code><a href='#index-declare' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-declare"></a><span><code class="code">declare</code><a class="copiable-link" href="#index-declare"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">declare [-aAfFgiIlnrtux] [-p] [<var>name</var>[=<var>value</var>] …]
+<pre class="example-preformatted">declare [-aAfFgiIlnrtux] [-p] [<var class="var">name</var>[=<var class="var">value</var>] ...]
</pre></div>
-<p>Declare variables and give them attributes. If no <var>name</var>s
+<p>Declare variables and give them attributes. If no <var class="var">name</var>s
are given, then display the values of variables instead.
</p>
-<p>The <samp>-p</samp> option will display the attributes and values of each
-<var>name</var>.
-When <samp>-p</samp> is used with <var>name</var> arguments, additional options,
-other than <samp>-f</samp> and <samp>-F</samp>, are ignored.
+<p>The <samp class="option">-p</samp> option will display the attributes and values of each
+<var class="var">name</var>.
+When <samp class="option">-p</samp> is used with <var class="var">name</var> arguments, additional options,
+other than <samp class="option">-f</samp> and <samp class="option">-F</samp>, are ignored.
</p>
-<p>When <samp>-p</samp> is supplied without <var>name</var> arguments, <code>declare</code>
+<p>When <samp class="option">-p</samp> is supplied without <var class="var">name</var> arguments, <code class="code">declare</code>
will display the attributes and values of all variables having the
attributes specified by the additional options.
-If no other options are supplied with <samp>-p</samp>, <code>declare</code> will
-display the attributes and values of all shell variables. The <samp>-f</samp>
+If no other options are supplied with <samp class="option">-p</samp>, <code class="code">declare</code> will
+display the attributes and values of all shell variables. The <samp class="option">-f</samp>
option will restrict the display to shell functions.
</p>
-<p>The <samp>-F</samp> option inhibits the display of function definitions;
+<p>The <samp class="option">-F</samp> option inhibits the display of function definitions;
only the function name and attributes are printed.
-If the <code>extdebug</code> shell option is enabled using <code>shopt</code>
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), the source file name and line number where
-each <var>name</var> is defined are displayed as well.
-<samp>-F</samp> implies <samp>-f</samp>.
+If the <code class="code">extdebug</code> shell option is enabled using <code class="code">shopt</code>
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>), the source file name and line number where
+each <var class="var">name</var> is defined are displayed as well.
+<samp class="option">-F</samp> implies <samp class="option">-f</samp>.
</p>
-<p>The <samp>-g</samp> option forces variables to be created or modified at
-the global scope, even when <code>declare</code> is executed in a shell function.
+<p>The <samp class="option">-g</samp> option forces variables to be created or modified at
+the global scope, even when <code class="code">declare</code> is executed in a shell function.
It is ignored in all other cases.
</p>
-<p>The <samp>-I</samp> option causes local variables to inherit the attributes
-(except the <code>nameref</code> attribute)
+<p>The <samp class="option">-I</samp> option causes local variables to inherit the attributes
+(except the <code class="code">nameref</code> attribute)
and value of any existing variable with the same
-<var>name</var> at a surrounding scope.
+<var class="var">name</var> at a surrounding scope.
If there is no existing variable, the local variable is initially unset.
</p>
<p>The following options can be used to restrict output to variables with
the specified attributes or to give variables attributes:
</p>
-<dl compact="compact">
-<dt><span><code>-a</code></span></dt>
-<dd><p>Each <var>name</var> is an indexed array variable (see <a href="#Arrays">Arrays</a>).
+<dl class="table">
+<dt><code class="code">-a</code></dt>
+<dd><p>Each <var class="var">name</var> is an indexed array variable (see <a class="pxref" href="#Arrays">Arrays</a>).
</p>
</dd>
-<dt><span><code>-A</code></span></dt>
-<dd><p>Each <var>name</var> is an associative array variable (see <a href="#Arrays">Arrays</a>).
+<dt><code class="code">-A</code></dt>
+<dd><p>Each <var class="var">name</var> is an associative array variable (see <a class="pxref" href="#Arrays">Arrays</a>).
</p>
</dd>
-<dt><span><code>-f</code></span></dt>
+<dt><code class="code">-f</code></dt>
<dd><p>Use function names only.
</p>
</dd>
-<dt><span><code>-i</code></span></dt>
+<dt><code class="code">-i</code></dt>
<dd><p>The variable is to be treated as
-an integer; arithmetic evaluation (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>) is
+an integer; arithmetic evaluation (see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>) is
performed when the variable is assigned a value.
</p>
</dd>
-<dt><span><code>-l</code></span></dt>
+<dt><code class="code">-l</code></dt>
<dd><p>When the variable is assigned a value, all upper-case characters are
converted to lower-case.
The upper-case attribute is disabled.
</p>
</dd>
-<dt><span><code>-n</code></span></dt>
-<dd><p>Give each <var>name</var> the <code>nameref</code> attribute, making
+<dt><code class="code">-n</code></dt>
+<dd><p>Give each <var class="var">name</var> the <code class="code">nameref</code> attribute, making
it a name reference to another variable.
-That other variable is defined by the value of <var>name</var>.
+That other variable is defined by the value of <var class="var">name</var>.
All references, assignments, and attribute modifications
-to <var>name</var>, except for those using or changing the
-<samp>-n</samp> attribute itself, are performed on the variable referenced by
-<var>name</var>’s value.
+to <var class="var">name</var>, except for those using or changing the
+<samp class="option">-n</samp> attribute itself, are performed on the variable referenced by
+<var class="var">name</var>’s value.
The nameref attribute cannot be applied to array variables.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
-<dd><p>Make <var>name</var>s readonly. These names cannot then be assigned values
+<dt><code class="code">-r</code></dt>
+<dd><p>Make <var class="var">name</var>s readonly. These names cannot then be assigned values
by subsequent assignment statements or unset.
</p>
</dd>
-<dt><span><code>-t</code></span></dt>
-<dd><p>Give each <var>name</var> the <code>trace</code> attribute.
-Traced functions inherit the <code>DEBUG</code> and <code>RETURN</code> traps from
+<dt><code class="code">-t</code></dt>
+<dd><p>Give each <var class="var">name</var> the <code class="code">trace</code> attribute.
+Traced functions inherit the <code class="code">DEBUG</code> and <code class="code">RETURN</code> traps from
the calling shell.
The trace attribute has no special meaning for variables.
</p>
</dd>
-<dt><span><code>-u</code></span></dt>
+<dt><code class="code">-u</code></dt>
<dd><p>When the variable is assigned a value, all lower-case characters are
converted to upper-case.
The lower-case attribute is disabled.
</p>
</dd>
-<dt><span><code>-x</code></span></dt>
-<dd><p>Mark each <var>name</var> for export to subsequent commands via
+<dt><code class="code">-x</code></dt>
+<dd><p>Mark each <var class="var">name</var> for export to subsequent commands via
the environment.
</p></dd>
</dl>
-<p>Using ‘<samp>+</samp>’ instead of ‘<samp>-</samp>’ turns off the attribute instead,
-with the exceptions that ‘<samp>+a</samp>’ and ‘<samp>+A</samp>’
-may not be used to destroy array variables and ‘<samp>+r</samp>’ will not
+<p>Using ‘<samp class="samp">+</samp>’ instead of ‘<samp class="samp">-</samp>’ turns off the attribute instead,
+with the exceptions that ‘<samp class="samp">+a</samp>’ and ‘<samp class="samp">+A</samp>’
+may not be used to destroy array variables and ‘<samp class="samp">+r</samp>’ will not
remove the readonly attribute.
-When used in a function, <code>declare</code> makes each <var>name</var> local,
-as with the <code>local</code> command, unless the <samp>-g</samp> option is used.
-If a variable name is followed by =<var>value</var>, the value of the variable
-is set to <var>value</var>.
+When used in a function, <code class="code">declare</code> makes each <var class="var">name</var> local,
+as with the <code class="code">local</code> command, unless the <samp class="option">-g</samp> option is used.
+If a variable name is followed by =<var class="var">value</var>, the value of the variable
+is set to <var class="var">value</var>.
</p>
-<p>When using <samp>-a</samp> or <samp>-A</samp> and the compound assignment syntax to
+<p>When using <samp class="option">-a</samp> or <samp class="option">-A</samp> and the compound assignment syntax to
create array variables, additional attributes do not take effect until
subsequent assignments.
</p>
<p>The return status is zero unless an invalid option is encountered,
-an attempt is made to define a function using ‘<samp>-f foo=bar</samp>’,
+an attempt is made to define a function using ‘<samp class="samp">-f foo=bar</samp>’,
an attempt is made to assign a value to a readonly variable,
an attempt is made to assign a value to an array variable without
-using the compound assignment syntax (see <a href="#Arrays">Arrays</a>),
-one of the <var>name</var>s is not a valid shell variable name,
+using the compound assignment syntax (see <a class="pxref" href="#Arrays">Arrays</a>),
+one of the <var class="var">name</var>s is not a valid shell variable name,
an attempt is made to turn off readonly status for a readonly variable,
an attempt is made to turn off array status for an array variable,
-or an attempt is made to display a non-existent function with <samp>-f</samp>.
+or an attempt is made to display a non-existent function with <samp class="option">-f</samp>.
</p>
</dd>
-<dt id='index-echo'><span><code>echo</code><a href='#index-echo' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-echo"></a><span><code class="code">echo</code><a class="copiable-link" href="#index-echo"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">echo [-neE] [<var>arg</var> …]
+<pre class="example-preformatted">echo [-neE] [<var class="var">arg</var> ...]
</pre></div>
-<p>Output the <var>arg</var>s, separated by spaces, terminated with a
+<p>Output the <var class="var">arg</var>s, separated by spaces, terminated with a
newline.
The return status is 0 unless a write error occurs.
-If <samp>-n</samp> is specified, the trailing newline is suppressed.
-If the <samp>-e</samp> option is given, interpretation of the following
+If <samp class="option">-n</samp> is specified, the trailing newline is suppressed.
+If the <samp class="option">-e</samp> option is given, interpretation of the following
backslash-escaped characters is enabled.
-The <samp>-E</samp> option disables the interpretation of these escape characters,
+The <samp class="option">-E</samp> option disables the interpretation of these escape characters,
even on systems where they are interpreted by default.
-The <code>xpg_echo</code> shell option may be used to
-dynamically determine whether or not <code>echo</code>
+The <code class="code">xpg_echo</code> shell option may be used to
+dynamically determine whether or not <code class="code">echo</code>
interprets any options and
expands these escape characters by default.
-<code>echo</code> does not interpret <samp>--</samp> to mean the end of options.
+<code class="code">echo</code> does not interpret <samp class="option">--</samp> to mean the end of options.
</p>
-<p><code>echo</code> interprets the following escape sequences:
-</p><dl compact="compact">
-<dt><span><code>\a</code></span></dt>
+<p><code class="code">echo</code> interprets the following escape sequences:
+</p><dl class="table">
+<dt><code class="code">\a</code></dt>
<dd><p>alert (bell)
</p></dd>
-<dt><span><code>\b</code></span></dt>
+<dt><code class="code">\b</code></dt>
<dd><p>backspace
</p></dd>
-<dt><span><code>\c</code></span></dt>
+<dt><code class="code">\c</code></dt>
<dd><p>suppress further output
</p></dd>
-<dt><span><code>\e</code></span></dt>
-<dt><span><code>\E</code></span></dt>
+<dt><code class="code">\e</code></dt>
+<dt><code class="code">\E</code></dt>
<dd><p>escape
</p></dd>
-<dt><span><code>\f</code></span></dt>
+<dt><code class="code">\f</code></dt>
<dd><p>form feed
</p></dd>
-<dt><span><code>\n</code></span></dt>
+<dt><code class="code">\n</code></dt>
<dd><p>new line
</p></dd>
-<dt><span><code>\r</code></span></dt>
+<dt><code class="code">\r</code></dt>
<dd><p>carriage return
</p></dd>
-<dt><span><code>\t</code></span></dt>
+<dt><code class="code">\t</code></dt>
<dd><p>horizontal tab
</p></dd>
-<dt><span><code>\v</code></span></dt>
+<dt><code class="code">\v</code></dt>
<dd><p>vertical tab
</p></dd>
-<dt><span><code>\\</code></span></dt>
+<dt><code class="code">\\</code></dt>
<dd><p>backslash
</p></dd>
-<dt><span><code>\0<var>nnn</var></code></span></dt>
-<dd><p>the eight-bit character whose value is the octal value <var>nnn</var>
+<dt><code class="code">\0<var class="var">nnn</var></code></dt>
+<dd><p>the eight-bit character whose value is the octal value <var class="var">nnn</var>
(zero to three octal digits)
</p></dd>
-<dt><span><code>\x<var>HH</var></code></span></dt>
-<dd><p>the eight-bit character whose value is the hexadecimal value <var>HH</var>
+<dt><code class="code">\x<var class="var">HH</var></code></dt>
+<dd><p>the eight-bit character whose value is the hexadecimal value <var class="var">HH</var>
(one or two hex digits)
</p></dd>
-<dt><span><code>\u<var>HHHH</var></code></span></dt>
+<dt><code class="code">\u<var class="var">HHHH</var></code></dt>
<dd><p>the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
-<var>HHHH</var> (one to four hex digits)
+<var class="var">HHHH</var> (one to four hex digits)
</p></dd>
-<dt><span><code>\U<var>HHHHHHHH</var></code></span></dt>
+<dt><code class="code">\U<var class="var">HHHHHHHH</var></code></dt>
<dd><p>the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
-<var>HHHHHHHH</var> (one to eight hex digits)
+<var class="var">HHHHHHHH</var> (one to eight hex digits)
</p></dd>
</dl>
</dd>
-<dt id='index-enable'><span><code>enable</code><a href='#index-enable' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-enable"></a><span><code class="code">enable</code><a class="copiable-link" href="#index-enable"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">enable [-a] [-dnps] [-f <var>filename</var>] [<var>name</var> …]
+<pre class="example-preformatted">enable [-a] [-dnps] [-f <var class="var">filename</var>] [<var class="var">name</var> ...]
</pre></div>
<p>Enable and disable builtin shell commands.
Disabling a builtin allows a disk command which has the same name
as a shell builtin to be executed without specifying a full pathname,
even though the shell normally searches for builtins before disk commands.
-If <samp>-n</samp> is used, the <var>name</var>s become disabled. Otherwise
-<var>name</var>s are enabled. For example, to use the <code>test</code> binary
-found via <code>$PATH</code> instead of the shell builtin version, type
-‘<samp>enable -n test</samp>’.
+If <samp class="option">-n</samp> is used, the <var class="var">name</var>s become disabled. Otherwise
+<var class="var">name</var>s are enabled. For example, to use the <code class="code">test</code> binary
+found via <code class="env">$PATH</code> instead of the shell builtin version, type
+‘<samp class="samp">enable -n test</samp>’.
</p>
-<p>If the <samp>-p</samp> option is supplied, or no <var>name</var> arguments appear,
+<p>If the <samp class="option">-p</samp> option is supplied, or no <var class="var">name</var> arguments appear,
a list of shell builtins is printed. With no other arguments, the list
consists of all enabled shell builtins.
-The <samp>-a</samp> option means to list
+The <samp class="option">-a</samp> option means to list
each builtin with an indication of whether or not it is enabled.
</p>
-<p>The <samp>-f</samp> option means to load the new builtin command <var>name</var>
-from shared object <var>filename</var>, on systems that support dynamic loading.
-Bash will use the value of the <code>BASH_LOADABLES_PATH</code> variable as a
-colon-separated list of directories in which to search for <var>filename</var>,
-if <var>filename</var> does not contain a slash.
+<p>The <samp class="option">-f</samp> option means to load the new builtin command <var class="var">name</var>
+from shared object <var class="var">filename</var>, on systems that support dynamic loading.
+Bash will use the value of the <code class="env">BASH_LOADABLES_PATH</code> variable as a
+colon-separated list of directories in which to search for <var class="var">filename</var>,
+if <var class="var">filename</var> does not contain a slash.
The default is system-dependent,
and may include "." to force a search of the current directory.
-The <samp>-d</samp> option will delete a builtin loaded with <samp>-f</samp>.
+The <samp class="option">-d</samp> option will delete a builtin loaded with <samp class="option">-f</samp>.
</p>
<p>If there are no options, a list of the shell builtins is displayed.
-The <samp>-s</samp> option restricts <code>enable</code> to the <small>POSIX</small> special
-builtins. If <samp>-s</samp> is used with <samp>-f</samp>, the new builtin becomes
-a special builtin (see <a href="#Special-Builtins">Special Builtins</a>).
+The <samp class="option">-s</samp> option restricts <code class="code">enable</code> to the <small class="sc">POSIX</small> special
+builtins. If <samp class="option">-s</samp> is used with <samp class="option">-f</samp>, the new builtin becomes
+a special builtin (see <a class="pxref" href="#Special-Builtins">Special Builtins</a>).
</p>
-<p>If no options are supplied and a <var>name</var> is not a shell builtin,
-<code>enable</code> will attempt to load <var>name</var> from a shared object named
-<var>name</var>, as if the command were
-‘<samp>enable -f <var>name</var> <var>name</var></samp>’.
+<p>If no options are supplied and a <var class="var">name</var> is not a shell builtin,
+<code class="code">enable</code> will attempt to load <var class="var">name</var> from a shared object named
+<var class="var">name</var>, as if the command were
+‘<samp class="samp">enable -f <var class="var">name</var> <var class="var">name</var></samp>’.
</p>
-<p>The return status is zero unless a <var>name</var> is not a shell builtin
+<p>The return status is zero unless a <var class="var">name</var> is not a shell builtin
or there is an error loading a new builtin from a shared object.
</p>
</dd>
-<dt id='index-help'><span><code>help</code><a href='#index-help' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-help"></a><span><code class="code">help</code><a class="copiable-link" href="#index-help"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">help [-dms] [<var>pattern</var>]
+<pre class="example-preformatted">help [-dms] [<var class="var">pattern</var>]
</pre></div>
<p>Display helpful information about builtin commands.
-If <var>pattern</var> is specified, <code>help</code> gives detailed help
-on all commands matching <var>pattern</var>, otherwise a list of
+If <var class="var">pattern</var> is specified, <code class="code">help</code> gives detailed help
+on all commands matching <var class="var">pattern</var>, otherwise a list of
the builtins is printed.
</p>
<p>Options, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-d</code></span></dt>
-<dd><p>Display a short description of each <var>pattern</var>
+<dl class="table">
+<dt><code class="code">-d</code></dt>
+<dd><p>Display a short description of each <var class="var">pattern</var>
</p></dd>
-<dt><span><code>-m</code></span></dt>
-<dd><p>Display the description of each <var>pattern</var> in a manpage-like format
+<dt><code class="code">-m</code></dt>
+<dd><p>Display the description of each <var class="var">pattern</var> in a manpage-like format
</p></dd>
-<dt><span><code>-s</code></span></dt>
-<dd><p>Display only a short usage synopsis for each <var>pattern</var>
+<dt><code class="code">-s</code></dt>
+<dd><p>Display only a short usage synopsis for each <var class="var">pattern</var>
</p></dd>
</dl>
-<p>The return status is zero unless no command matches <var>pattern</var>.
+<p>The return status is zero unless no command matches <var class="var">pattern</var>.
</p>
</dd>
-<dt id='index-let'><span><code>let</code><a href='#index-let' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-let"></a><span><code class="code">let</code><a class="copiable-link" href="#index-let"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">let <var>expression</var> [<var>expression</var> …]
+<pre class="example-preformatted">let <var class="var">expression</var> [<var class="var">expression</var> ...]
</pre></div>
-<p>The <code>let</code> builtin allows arithmetic to be performed on shell
-variables. Each <var>expression</var> is evaluated according to the
-rules given below in <a href="#Shell-Arithmetic">Shell Arithmetic</a>. If the
-last <var>expression</var> evaluates to 0, <code>let</code> returns 1;
+<p>The <code class="code">let</code> builtin allows arithmetic to be performed on shell
+variables. Each <var class="var">expression</var> is evaluated according to the
+rules given below in <a class="ref" href="#Shell-Arithmetic">Shell Arithmetic</a>. If the
+last <var class="var">expression</var> evaluates to 0, <code class="code">let</code> returns 1;
otherwise 0 is returned.
</p>
</dd>
-<dt id='index-local'><span><code>local</code><a href='#index-local' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-local"></a><span><code class="code">local</code><a class="copiable-link" href="#index-local"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">local [<var>option</var>] <var>name</var>[=<var>value</var>] …
+<pre class="example-preformatted">local [<var class="var">option</var>] <var class="var">name</var>[=<var class="var">value</var>] ...
</pre></div>
-<p>For each argument, a local variable named <var>name</var> is created,
-and assigned <var>value</var>.
-The <var>option</var> can be any of the options accepted by <code>declare</code>.
-<code>local</code> can only be used within a function; it makes the variable
-<var>name</var> have a visible scope restricted to that function and its
+<p>For each argument, a local variable named <var class="var">name</var> is created,
+and assigned <var class="var">value</var>.
+The <var class="var">option</var> can be any of the options accepted by <code class="code">declare</code>.
+<code class="code">local</code> can only be used within a function; it makes the variable
+<var class="var">name</var> have a visible scope restricted to that function and its
children.
-If <var>name</var> is ‘<samp>-</samp>’, the set of shell options is made local to the
-function in which <code>local</code> is invoked: shell options changed using
-the <code>set</code> builtin inside the function
-after the call to <code>local</code>
+If <var class="var">name</var> is ‘<samp class="samp">-</samp>’, the set of shell options is made local to the
+function in which <code class="code">local</code> is invoked: shell options changed using
+the <code class="code">set</code> builtin inside the function
+after the call to <code class="code">local</code>
are restored to their original
values when the function returns.
-The restore is effected as if a series of <code>set</code> commands were executed
+The restore is effected as if a series of <code class="code">set</code> commands were executed
to restore the values that were in place before the function.
-The return status is zero unless <code>local</code> is used outside
-a function, an invalid <var>name</var> is supplied, or <var>name</var> is a
+The return status is zero unless <code class="code">local</code> is used outside
+a function, an invalid <var class="var">name</var> is supplied, or <var class="var">name</var> is a
readonly variable.
</p>
</dd>
-<dt id='index-logout'><span><code>logout</code><a href='#index-logout' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-logout"></a><span><code class="code">logout</code><a class="copiable-link" href="#index-logout"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">logout [<var>n</var>]
+<pre class="example-preformatted">logout [<var class="var">n</var>]
</pre></div>
-<p>Exit a login shell, returning a status of <var>n</var> to the shell’s
+<p>Exit a login shell, returning a status of <var class="var">n</var> to the shell’s
parent.
</p>
</dd>
-<dt id='index-mapfile'><span><code>mapfile</code><a href='#index-mapfile' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-mapfile"></a><span><code class="code">mapfile</code><a class="copiable-link" href="#index-mapfile"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">mapfile [-d <var>delim</var>] [-n <var>count</var>] [-O <var>origin</var>] [-s <var>count</var>]
- [-t] [-u <var>fd</var>] [-C <var>callback</var>] [-c <var>quantum</var>] [<var>array</var>]
+<pre class="example-preformatted">mapfile [-d <var class="var">delim</var>] [-n <var class="var">count</var>] [-O <var class="var">origin</var>] [-s <var class="var">count</var>]
+ [-t] [-u <var class="var">fd</var>] [-C <var class="var">callback</var>] [-c <var class="var">quantum</var>] [<var class="var">array</var>]
</pre></div>
-<p>Read lines from the standard input into the indexed array variable <var>array</var>,
-or from file descriptor <var>fd</var>
-if the <samp>-u</samp> option is supplied.
-The variable <code>MAPFILE</code> is the default <var>array</var>.
+<p>Read lines from the standard input into the indexed array variable <var class="var">array</var>,
+or from file descriptor <var class="var">fd</var>
+if the <samp class="option">-u</samp> option is supplied.
+The variable <code class="code">MAPFILE</code> is the default <var class="var">array</var>.
Options, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-d</code></span></dt>
-<dd><p>The first character of <var>delim</var> is used to terminate each input line,
+<dl class="table">
+<dt><code class="code">-d</code></dt>
+<dd><p>The first character of <var class="var">delim</var> is used to terminate each input line,
rather than newline.
-If <var>delim</var> is the empty string, <code>mapfile</code> will terminate a line
+If <var class="var">delim</var> is the empty string, <code class="code">mapfile</code> will terminate a line
when it reads a NUL character.
</p></dd>
-<dt><span><code>-n</code></span></dt>
-<dd><p>Copy at most <var>count</var> lines. If <var>count</var> is 0, all lines are copied.
+<dt><code class="code">-n</code></dt>
+<dd><p>Copy at most <var class="var">count</var> lines. If <var class="var">count</var> is 0, all lines are copied.
</p></dd>
-<dt><span><code>-O</code></span></dt>
-<dd><p>Begin assigning to <var>array</var> at index <var>origin</var>.
+<dt><code class="code">-O</code></dt>
+<dd><p>Begin assigning to <var class="var">array</var> at index <var class="var">origin</var>.
The default index is 0.
</p></dd>
-<dt><span><code>-s</code></span></dt>
-<dd><p>Discard the first <var>count</var> lines read.
+<dt><code class="code">-s</code></dt>
+<dd><p>Discard the first <var class="var">count</var> lines read.
</p></dd>
-<dt><span><code>-t</code></span></dt>
-<dd><p>Remove a trailing <var>delim</var> (default newline) from each line read.
+<dt><code class="code">-t</code></dt>
+<dd><p>Remove a trailing <var class="var">delim</var> (default newline) from each line read.
</p></dd>
-<dt><span><code>-u</code></span></dt>
-<dd><p>Read lines from file descriptor <var>fd</var> instead of the standard input.
+<dt><code class="code">-u</code></dt>
+<dd><p>Read lines from file descriptor <var class="var">fd</var> instead of the standard input.
</p></dd>
-<dt><span><code>-C</code></span></dt>
-<dd><p>Evaluate <var>callback</var> each time <var>quantum</var> lines are read.
-The <samp>-c</samp> option specifies <var>quantum</var>.
+<dt><code class="code">-C</code></dt>
+<dd><p>Evaluate <var class="var">callback</var> each time <var class="var">quantum</var> lines are read.
+The <samp class="option">-c</samp> option specifies <var class="var">quantum</var>.
</p></dd>
-<dt><span><code>-c</code></span></dt>
-<dd><p>Specify the number of lines read between each call to <var>callback</var>.
+<dt><code class="code">-c</code></dt>
+<dd><p>Specify the number of lines read between each call to <var class="var">callback</var>.
</p></dd>
</dl>
-<p>If <samp>-C</samp> is specified without <samp>-c</samp>,
+<p>If <samp class="option">-C</samp> is specified without <samp class="option">-c</samp>,
the default quantum is 5000.
-When <var>callback</var> is evaluated, it is supplied the index of the next
+When <var class="var">callback</var> is evaluated, it is supplied the index of the next
array element to be assigned and the line to be assigned to that element
as additional arguments.
-<var>callback</var> is evaluated after the line is read but before the
+<var class="var">callback</var> is evaluated after the line is read but before the
array element is assigned.
</p>
-<p>If not supplied with an explicit origin, <code>mapfile</code> will clear <var>array</var>
+<p>If not supplied with an explicit origin, <code class="code">mapfile</code> will clear <var class="var">array</var>
before assigning to it.
</p>
-<p><code>mapfile</code> returns successfully unless an invalid option or option
-argument is supplied, <var>array</var> is invalid or unassignable, or <var>array</var>
+<p><code class="code">mapfile</code> returns successfully unless an invalid option or option
+argument is supplied, <var class="var">array</var> is invalid or unassignable, or <var class="var">array</var>
is not an indexed array.
</p>
</dd>
-<dt id='index-printf'><span><code>printf</code><a href='#index-printf' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-printf"></a><span><code class="code">printf</code><a class="copiable-link" href="#index-printf"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">printf [-v <var>var</var>] <var>format</var> [<var>arguments</var>]
+<pre class="example-preformatted">printf [-v <var class="var">var</var>] <var class="var">format</var> [<var class="var">arguments</var>]
</pre></div>
-<p>Write the formatted <var>arguments</var> to the standard output under the
-control of the <var>format</var>.
-The <samp>-v</samp> option causes the output to be assigned to the variable
-<var>var</var> rather than being printed to the standard output.
+<p>Write the formatted <var class="var">arguments</var> to the standard output under the
+control of the <var class="var">format</var>.
+The <samp class="option">-v</samp> option causes the output to be assigned to the variable
+<var class="var">var</var> rather than being printed to the standard output.
</p>
-<p>The <var>format</var> is a character string which contains three types of objects:
+<p>The <var class="var">format</var> is a character string which contains three types of objects:
plain characters, which are simply copied to standard output, character
escape sequences, which are converted and copied to the standard output, and
format specifications, each of which causes printing of the next successive
-<var>argument</var>.
-In addition to the standard <code>printf(3)</code> format characters
-<code>csndiouxXeEfFgGaA</code>,
-<code>printf</code> interprets the following additional format specifiers:
-</p>
-<dl compact="compact">
-<dt><span><code>%b</code></span></dt>
-<dd><p>Causes <code>printf</code> to expand backslash escape sequences in the
-corresponding <var>argument</var> in the same way as <code>echo -e</code>
-(see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+<var class="var">argument</var>.
+In addition to the standard <code class="code">printf(3)</code> format characters
+<code class="code">csndiouxXeEfFgGaA</code>,
+<code class="code">printf</code> interprets the following additional format specifiers:
+</p>
+<dl class="table">
+<dt><code class="code">%b</code></dt>
+<dd><p>Causes <code class="code">printf</code> to expand backslash escape sequences in the
+corresponding <var class="var">argument</var> in the same way as <code class="code">echo -e</code>
+(see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p></dd>
-<dt><span><code>%q</code></span></dt>
-<dd><p>Causes <code>printf</code> to output the
-corresponding <var>argument</var> in a format that can be reused as shell input.
-<code>%q</code> and <code>%Q</code>P use the ANSI-C quoting style (see <a href="#ANSI_002dC-Quoting">ANSI-C Quoting</a>)
+<dt><code class="code">%q</code></dt>
+<dd><p>Causes <code class="code">printf</code> to output the
+corresponding <var class="var">argument</var> in a format that can be reused as shell input.
+<code class="code">%q</code> and <code class="code">%Q</code>P use the ANSI-C quoting style (see <a class="pxref" href="#ANSI_002dC-Quoting">ANSI-C Quoting</a>)
if any characters
in the argument string require it, and backslash quoting otherwise.
-If the format string uses the <code>printf</code> <var>alternate form</var>, these two
+If the format string uses the <code class="code">printf</code> <var class="var">alternate form</var>, these two
formats quote the argument string using single quotes.
</p>
</dd>
-<dt><span><code>%Q</code></span></dt>
-<dd><p>like <code>%q</code>, but applies any supplied precision to the <var>argument</var>
+<dt><code class="code">%Q</code></dt>
+<dd><p>like <code class="code">%q</code>, but applies any supplied precision to the <var class="var">argument</var>
before quoting it.
</p>
</dd>
-<dt><span><code>%(<var>datefmt</var>)T</code></span></dt>
-<dd><p>Causes <code>printf</code> to output the date-time string resulting from using
-<var>datefmt</var> as a format string for <code>strftime</code>(3).
-The corresponding <var>argument</var> is an integer representing the number of
+<dt><code class="code">%(<var class="var">datefmt</var>)T</code></dt>
+<dd><p>Causes <code class="code">printf</code> to output the date-time string resulting from using
+<var class="var">datefmt</var> as a format string for <code class="code">strftime</code>(3).
+The corresponding <var class="var">argument</var> is an integer representing the number of
seconds since the epoch.
Two special argument values may be used: -1 represents the current
time, and -2 represents the time the shell was invoked.
If no argument is specified, conversion behaves as if -1 had been given.
-This is an exception to the usual <code>printf</code> behavior.
+This is an exception to the usual <code class="code">printf</code> behavior.
</p></dd>
</dl>
character is a single or double quote, the value is the ASCII value of
the following character.
</p>
-<p>The <var>format</var> is reused as necessary to consume all of the <var>arguments</var>.
-If the <var>format</var> requires more <var>arguments</var> than are supplied, the
+<p>The <var class="var">format</var> is reused as necessary to consume all of the <var class="var">arguments</var>.
+If the <var class="var">format</var> requires more <var class="var">arguments</var> than are supplied, the
extra format specifications behave as if a zero value or null string, as
appropriate, had been supplied.
The return value is zero on success,
occurs.
</p>
</dd>
-<dt id='index-read'><span><code>read</code><a href='#index-read' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-read"></a><span><code class="code">read</code><a class="copiable-link" href="#index-read"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">read [-Eers] [-a <var>aname</var>] [-d <var>delim</var>] [-i <var>text</var>] [-n <var>nchars</var>]
- [-N <var>nchars</var>] [-p <var>prompt</var>] [-t <var>timeout</var>] [-u <var>fd</var>] [<var>name</var> …]
+<pre class="example-preformatted">read [-Eers] [-a <var class="var">aname</var>] [-d <var class="var">delim</var>] [-i <var class="var">text</var>] [-n <var class="var">nchars</var>]
+ [-N <var class="var">nchars</var>] [-p <var class="var">prompt</var>] [-t <var class="var">timeout</var>] [-u <var class="var">fd</var>] [<var class="var">name</var> ...]
</pre></div>
<p>One line is read from the standard input, or from the file descriptor
-<var>fd</var> supplied as an argument to the <samp>-u</samp> option,
-split into words as described above in <a href="#Word-Splitting">Word Splitting</a>,
+<var class="var">fd</var> supplied as an argument to the <samp class="option">-u</samp> option,
+split into words as described above in <a class="ref" href="#Word-Splitting">Word Splitting</a>,
and the first word
-is assigned to the first <var>name</var>, the second word to the second <var>name</var>,
+is assigned to the first <var class="var">name</var>, the second word to the second <var class="var">name</var>,
and so on.
If there are more words than names,
the remaining words and their intervening delimiters are assigned
-to the last <var>name</var>.
+to the last <var class="var">name</var>.
If there are fewer words read from the input stream than names,
the remaining names are assigned empty values.
-The characters in the value of the <code>IFS</code> variable
+The characters in the value of the <code class="env">IFS</code> variable
are used to split the line into words using the same rules the shell
-uses for expansion (described above in <a href="#Word-Splitting">Word Splitting</a>).
-The backslash character ‘<samp>\</samp>’ may be used to remove any special
+uses for expansion (described above in <a class="ref" href="#Word-Splitting">Word Splitting</a>).
+The backslash character ‘<samp class="samp">\</samp>’ may be used to remove any special
meaning for the next character read and for line continuation.
</p>
<p>Options, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-a <var>aname</var></code></span></dt>
+<dl class="table">
+<dt><code class="code">-a <var class="var">aname</var></code></dt>
<dd><p>The words are assigned to sequential indices of the array variable
-<var>aname</var>, starting at 0.
-All elements are removed from <var>aname</var> before the assignment.
-Other <var>name</var> arguments are ignored.
+<var class="var">aname</var>, starting at 0.
+All elements are removed from <var class="var">aname</var> before the assignment.
+Other <var class="var">name</var> arguments are ignored.
</p>
</dd>
-<dt><span><code>-d <var>delim</var></code></span></dt>
-<dd><p>The first character of <var>delim</var> is used to terminate the input line,
+<dt><code class="code">-d <var class="var">delim</var></code></dt>
+<dd><p>The first character of <var class="var">delim</var> is used to terminate the input line,
rather than newline.
-If <var>delim</var> is the empty string, <code>read</code> will terminate a line
+If <var class="var">delim</var> is the empty string, <code class="code">read</code> will terminate a line
when it reads a NUL character.
</p>
</dd>
-<dt><span><code>-e</code></span></dt>
-<dd><p>Readline (see <a href="#Command-Line-Editing">Command Line Editing</a>) is used to obtain the line.
+<dt><code class="code">-e</code></dt>
+<dd><p>Readline (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>) is used to obtain the line.
Readline uses the current (or default, if line editing was not previously
active) editing settings, but uses Readline’s default filename completion.
</p>
</dd>
-<dt><span><code>-E</code></span></dt>
-<dd><p>Readline (see <a href="#Command-Line-Editing">Command Line Editing</a>) is used to obtain the line.
+<dt><code class="code">-E</code></dt>
+<dd><p>Readline (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>) is used to obtain the line.
Readline uses the current (or default, if line editing was not previously
active) editing settings, but uses Bash’s default completion, including
programmable completion.
</p>
</dd>
-<dt><span><code>-i <var>text</var></code></span></dt>
-<dd><p>If Readline is being used to read the line, <var>text</var> is placed into
+<dt><code class="code">-i <var class="var">text</var></code></dt>
+<dd><p>If Readline is being used to read the line, <var class="var">text</var> is placed into
the editing buffer before editing begins.
</p>
</dd>
-<dt><span><code>-n <var>nchars</var></code></span></dt>
-<dd><p><code>read</code> returns after reading <var>nchars</var> characters rather than
+<dt><code class="code">-n <var class="var">nchars</var></code></dt>
+<dd><p><code class="code">read</code> returns after reading <var class="var">nchars</var> characters rather than
waiting for a complete line of input, but honors a delimiter if fewer
-than <var>nchars</var> characters are read before the delimiter.
+than <var class="var">nchars</var> characters are read before the delimiter.
</p>
</dd>
-<dt><span><code>-N <var>nchars</var></code></span></dt>
-<dd><p><code>read</code> returns after reading exactly <var>nchars</var> characters rather
+<dt><code class="code">-N <var class="var">nchars</var></code></dt>
+<dd><p><code class="code">read</code> returns after reading exactly <var class="var">nchars</var> characters rather
than waiting for a complete line of input, unless EOF is encountered or
-<code>read</code> times out.
+<code class="code">read</code> times out.
Delimiter characters encountered in the input are
-not treated specially and do not cause <code>read</code> to return until
-<var>nchars</var> characters are read.
-The result is not split on the characters in <code>IFS</code>; the intent is
+not treated specially and do not cause <code class="code">read</code> to return until
+<var class="var">nchars</var> characters are read.
+The result is not split on the characters in <code class="code">IFS</code>; the intent is
that the variable is assigned exactly the characters read
-(with the exception of backslash; see the <samp>-r</samp> option below).
+(with the exception of backslash; see the <samp class="option">-r</samp> option below).
</p>
</dd>
-<dt><span><code>-p <var>prompt</var></code></span></dt>
-<dd><p>Display <var>prompt</var>, without a trailing newline, before attempting
+<dt><code class="code">-p <var class="var">prompt</var></code></dt>
+<dd><p>Display <var class="var">prompt</var>, without a trailing newline, before attempting
to read any input.
The prompt is displayed only if input is coming from a terminal.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
+<dt><code class="code">-r</code></dt>
<dd><p>If this option is given, backslash does not act as an escape character.
The backslash is considered to be part of the line.
In particular, a backslash-newline pair may not then be used as a line
continuation.
</p>
</dd>
-<dt><span><code>-s</code></span></dt>
+<dt><code class="code">-s</code></dt>
<dd><p>Silent mode. If input is coming from a terminal, characters are
not echoed.
</p>
</dd>
-<dt><span><code>-t <var>timeout</var></code></span></dt>
-<dd><p>Cause <code>read</code> to time out and return failure if a complete line of
+<dt><code class="code">-t <var class="var">timeout</var></code></dt>
+<dd><p>Cause <code class="code">read</code> to time out and return failure if a complete line of
input (or a specified number of characters)
-is not read within <var>timeout</var> seconds.
-<var>timeout</var> may be a decimal number with a fractional portion following
+is not read within <var class="var">timeout</var> seconds.
+<var class="var">timeout</var> may be a decimal number with a fractional portion following
the decimal point.
-This option is only effective if <code>read</code> is reading input from a
+This option is only effective if <code class="code">read</code> is reading input from a
terminal, pipe, or other special file; it has no effect when reading
from regular files.
-If <code>read</code> times out, <code>read</code> saves any partial input read into
-the specified variable <var>name</var>.
-If <var>timeout</var> is 0, <code>read</code> returns immediately, without trying to
+If <code class="code">read</code> times out, <code class="code">read</code> saves any partial input read into
+the specified variable <var class="var">name</var>.
+If <var class="var">timeout</var> is 0, <code class="code">read</code> returns immediately, without trying to
read any data.
The exit status is 0 if input is available on the specified file descriptor,
or the read will return EOF,
The exit status is greater than 128 if the timeout is exceeded.
</p>
</dd>
-<dt><span><code>-u <var>fd</var></code></span></dt>
-<dd><p>Read input from file descriptor <var>fd</var>.
+<dt><code class="code">-u <var class="var">fd</var></code></dt>
+<dd><p>Read input from file descriptor <var class="var">fd</var>.
</p></dd>
</dl>
-<p>If no <var>name</var>s are supplied, the line read,
+<p>Other than the case where <var class="var">delim</var> is the empty string, <code class="code">read</code>
+ignores any NUL characters in the input.
+</p>
+<p>If no <var class="var">name</var>s are supplied, the line read,
without the ending delimiter but otherwise unmodified,
is assigned to the
-variable <code>REPLY</code>.
-The exit status is zero, unless end-of-file is encountered, <code>read</code>
+variable <code class="env">REPLY</code>.
+The exit status is zero, unless end-of-file is encountered, <code class="code">read</code>
times out (in which case the status is greater than 128),
a variable assignment error (such as assigning to a readonly variable) occurs,
-or an invalid file descriptor is supplied as the argument to <samp>-u</samp>.
+or an invalid file descriptor is supplied as the argument to <samp class="option">-u</samp>.
</p>
</dd>
-<dt id='index-readarray'><span><code>readarray</code><a href='#index-readarray' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-readarray"></a><span><code class="code">readarray</code><a class="copiable-link" href="#index-readarray"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">readarray [-d <var>delim</var>] [-n <var>count</var>] [-O <var>origin</var>] [-s <var>count</var>]
- [-t] [-u <var>fd</var>] [-C <var>callback</var>] [-c <var>quantum</var>] [<var>array</var>]
+<pre class="example-preformatted">readarray [-d <var class="var">delim</var>] [-n <var class="var">count</var>] [-O <var class="var">origin</var>] [-s <var class="var">count</var>]
+ [-t] [-u <var class="var">fd</var>] [-C <var class="var">callback</var>] [-c <var class="var">quantum</var>] [<var class="var">array</var>]
</pre></div>
-<p>Read lines from the standard input into the indexed array variable <var>array</var>,
-or from file descriptor <var>fd</var>
-if the <samp>-u</samp> option is supplied.
+<p>Read lines from the standard input into the indexed array variable <var class="var">array</var>,
+or from file descriptor <var class="var">fd</var>
+if the <samp class="option">-u</samp> option is supplied.
</p>
-<p>A synonym for <code>mapfile</code>.
+<p>A synonym for <code class="code">mapfile</code>.
</p>
</dd>
-<dt id='index-source'><span><code>source</code><a href='#index-source' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-source"></a><span><code class="code">source</code><a class="copiable-link" href="#index-source"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">source <var>filename</var>
+<pre class="example-preformatted">source <var class="var">filename</var>
</pre></div>
-<p>A synonym for <code>.</code> (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+<p>A synonym for <code class="code">.</code> (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
</p>
</dd>
-<dt id='index-type'><span><code>type</code><a href='#index-type' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-type"></a><span><code class="code">type</code><a class="copiable-link" href="#index-type"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">type [-afptP] [<var>name</var> …]
+<pre class="example-preformatted">type [-afptP] [<var class="var">name</var> ...]
</pre></div>
-<p>For each <var>name</var>, indicate how it would be interpreted if used as a
+<p>For each <var class="var">name</var>, indicate how it would be interpreted if used as a
command name.
</p>
-<p>If the <samp>-t</samp> option is used, <code>type</code> prints a single word
-which is one of ‘<samp>alias</samp>’, ‘<samp>keyword</samp>’, ‘<samp>function</samp>’,
-‘<samp>builtin</samp>’, or ‘<samp>file</samp>’,
-if <var>name</var> is an alias, shell reserved word, shell function,
+<p>If the <samp class="option">-t</samp> option is used, <code class="code">type</code> prints a single word
+which is one of ‘<samp class="samp">alias</samp>’, ‘<samp class="samp">keyword</samp>’, ‘<samp class="samp">function</samp>’,
+‘<samp class="samp">builtin</samp>’, or ‘<samp class="samp">file</samp>’,
+if <var class="var">name</var> is an alias, shell reserved word, shell function,
shell builtin, or executable disk file, respectively.
-If the <var>name</var> is not found, then nothing is printed, and
-<code>type</code> returns a failure status.
+If the <var class="var">name</var> is not found, then nothing is printed, and
+<code class="code">type</code> returns a failure status.
</p>
-<p>If the <samp>-p</samp> option is used, <code>type</code> either returns the name
-of the executable file that would be found by searching <code>$PATH</code>,
-or nothing if <samp>-t</samp> would not return ‘<samp>file</samp>’.
+<p>If the <samp class="option">-p</samp> option is used, <code class="code">type</code> either returns the name
+of the executable file that would be found by searching <code class="code">$PATH</code>,
+or nothing if <samp class="option">-t</samp> would not return ‘<samp class="samp">file</samp>’.
</p>
-<p>The <samp>-P</samp> option forces a path search for each <var>name</var>, even if
-<samp>-t</samp> would not return ‘<samp>file</samp>’.
+<p>The <samp class="option">-P</samp> option forces a path search for each <var class="var">name</var>, even if
+<samp class="option">-t</samp> would not return ‘<samp class="samp">file</samp>’.
</p>
-<p>If a <var>name</var> is present in the table of hashed commands,
-options <samp>-p</samp> and <samp>-P</samp> print the hashed value, which is not
-necessarily the file that appears first in <code>$PATH</code>.
+<p>If a <var class="var">name</var> is present in the table of hashed commands,
+options <samp class="option">-p</samp> and <samp class="option">-P</samp> print the hashed value, which is not
+necessarily the file that appears first in <code class="code">$PATH</code>.
</p>
-<p>If the <samp>-a</samp> option is used, <code>type</code> returns all of the places
-that contain a command named <var>name</var>.
+<p>If the <samp class="option">-a</samp> option is used, <code class="code">type</code> returns all of the places
+that contain a command named <var class="var">name</var>.
This includes aliases, reserved words, functions, and builtins,
-but the path search options (<samp>-p</samp> and <samp>-P</samp>) can be supplied
+but the path search options (<samp class="option">-p</samp> and <samp class="option">-P</samp>) can be supplied
to restrict the output to executable files.
-If <samp>-a</samp> is supplied with <samp>-p</samp>, <code>type</code> does not look
-in the table of hashed commands, and only performs a <code>PATH</code>
-search for <var>name</var>.
+If <samp class="option">-a</samp> is supplied with <samp class="option">-p</samp>, <code class="code">type</code> does not look
+in the table of hashed commands, and only performs a <code class="code">PATH</code>
+search for <var class="var">name</var>.
</p>
-<p>If the <samp>-f</samp> option is used, <code>type</code> does not attempt to find
-shell functions, as with the <code>command</code> builtin.
+<p>If the <samp class="option">-f</samp> option is used, <code class="code">type</code> does not attempt to find
+shell functions, as with the <code class="code">command</code> builtin.
</p>
-<p>The return status is zero if all of the <var>name</var>s are found, non-zero
+<p>The return status is zero if all of the <var class="var">name</var>s are found, non-zero
if any are not found.
</p>
</dd>
-<dt id='index-typeset'><span><code>typeset</code><a href='#index-typeset' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-typeset"></a><span><code class="code">typeset</code><a class="copiable-link" href="#index-typeset"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">typeset [-afFgrxilnrtux] [-p] [<var>name</var>[=<var>value</var>] …]
+<pre class="example-preformatted">typeset [-afFgrxilnrtux] [-p] [<var class="var">name</var>[=<var class="var">value</var>] ...]
</pre></div>
-<p>The <code>typeset</code> command is supplied for compatibility with the Korn
+<p>The <code class="code">typeset</code> command is supplied for compatibility with the Korn
shell.
-It is a synonym for the <code>declare</code> builtin command.
+It is a synonym for the <code class="code">declare</code> builtin command.
</p>
</dd>
-<dt id='index-ulimit'><span><code>ulimit</code><a href='#index-ulimit' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-ulimit"></a><span><code class="code">ulimit</code><a class="copiable-link" href="#index-ulimit"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">ulimit [-HS] -a
-ulimit [-HS] [-bcdefiklmnpqrstuvxPRT] [<var>limit</var>]
+<pre class="example-preformatted">ulimit [-HS] -a
+ulimit [-HS] [-bcdefiklmnpqrstuvxPRT] [<var class="var">limit</var>]
</pre></div>
-<p><code>ulimit</code> provides control over the resources available to processes
+<p><code class="code">ulimit</code> provides control over the resources available to processes
started by the shell, on systems that allow such control. If an
option is given, it is interpreted as follows:
</p>
-<dl compact="compact">
-<dt><span><code>-S</code></span></dt>
+<dl class="table">
+<dt><code class="code">-S</code></dt>
<dd><p>Change and report the soft limit associated with a resource.
</p>
</dd>
-<dt><span><code>-H</code></span></dt>
+<dt><code class="code">-H</code></dt>
<dd><p>Change and report the hard limit associated with a resource.
</p>
</dd>
-<dt><span><code>-a</code></span></dt>
+<dt><code class="code">-a</code></dt>
<dd><p>All current limits are reported; no limits are set.
</p>
</dd>
-<dt><span><code>-b</code></span></dt>
+<dt><code class="code">-b</code></dt>
<dd><p>The maximum socket buffer size.
</p>
</dd>
-<dt><span><code>-c</code></span></dt>
+<dt><code class="code">-c</code></dt>
<dd><p>The maximum size of core files created.
</p>
</dd>
-<dt><span><code>-d</code></span></dt>
+<dt><code class="code">-d</code></dt>
<dd><p>The maximum size of a process’s data segment.
</p>
</dd>
-<dt><span><code>-e</code></span></dt>
+<dt><code class="code">-e</code></dt>
<dd><p>The maximum scheduling priority ("nice").
</p>
</dd>
-<dt><span><code>-f</code></span></dt>
+<dt><code class="code">-f</code></dt>
<dd><p>The maximum size of files written by the shell and its children.
</p>
</dd>
-<dt><span><code>-i</code></span></dt>
+<dt><code class="code">-i</code></dt>
<dd><p>The maximum number of pending signals.
</p>
</dd>
-<dt><span><code>-k</code></span></dt>
+<dt><code class="code">-k</code></dt>
<dd><p>The maximum number of kqueues that may be allocated.
</p>
</dd>
-<dt><span><code>-l</code></span></dt>
+<dt><code class="code">-l</code></dt>
<dd><p>The maximum size that may be locked into memory.
</p>
</dd>
-<dt><span><code>-m</code></span></dt>
+<dt><code class="code">-m</code></dt>
<dd><p>The maximum resident set size (many systems do not honor this limit).
</p>
</dd>
-<dt><span><code>-n</code></span></dt>
+<dt><code class="code">-n</code></dt>
<dd><p>The maximum number of open file descriptors (most systems do not
allow this value to be set).
</p>
</dd>
-<dt><span><code>-p</code></span></dt>
+<dt><code class="code">-p</code></dt>
<dd><p>The pipe buffer size.
</p>
</dd>
-<dt><span><code>-q</code></span></dt>
-<dd><p>The maximum number of bytes in <small>POSIX</small> message queues.
+<dt><code class="code">-q</code></dt>
+<dd><p>The maximum number of bytes in <small class="sc">POSIX</small> message queues.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
+<dt><code class="code">-r</code></dt>
<dd><p>The maximum real-time scheduling priority.
</p>
</dd>
-<dt><span><code>-s</code></span></dt>
+<dt><code class="code">-s</code></dt>
<dd><p>The maximum stack size.
</p>
</dd>
-<dt><span><code>-t</code></span></dt>
+<dt><code class="code">-t</code></dt>
<dd><p>The maximum amount of cpu time in seconds.
</p>
</dd>
-<dt><span><code>-u</code></span></dt>
+<dt><code class="code">-u</code></dt>
<dd><p>The maximum number of processes available to a single user.
</p>
</dd>
-<dt><span><code>-v</code></span></dt>
+<dt><code class="code">-v</code></dt>
<dd><p>The maximum amount of virtual memory available to the shell, and, on
some systems, to its children.
</p>
</dd>
-<dt><span><code>-x</code></span></dt>
+<dt><code class="code">-x</code></dt>
<dd><p>The maximum number of file locks.
</p>
</dd>
-<dt><span><code>-P</code></span></dt>
+<dt><code class="code">-P</code></dt>
<dd><p>The maximum number of pseudoterminals.
</p>
</dd>
-<dt><span><code>-R</code></span></dt>
+<dt><code class="code">-R</code></dt>
<dd><p>The maximum time a real-time process can run before blocking, in microseconds.
</p>
</dd>
-<dt><span><code>-T</code></span></dt>
+<dt><code class="code">-T</code></dt>
<dd><p>The maximum number of threads.
</p></dd>
</dl>
-<p>If <var>limit</var> is given, and the <samp>-a</samp> option is not used,
-<var>limit</var> is the new value of the specified resource.
-The special <var>limit</var> values <code>hard</code>, <code>soft</code>, and
-<code>unlimited</code> stand for the current hard limit, the current soft limit,
+<p>If <var class="var">limit</var> is given, and the <samp class="option">-a</samp> option is not used,
+<var class="var">limit</var> is the new value of the specified resource.
+The special <var class="var">limit</var> values <code class="code">hard</code>, <code class="code">soft</code>, and
+<code class="code">unlimited</code> stand for the current hard limit, the current soft limit,
and no limit, respectively.
A hard limit cannot be increased by a non-root user once it is set;
a soft limit may be increased up to the value of the hard limit.
Otherwise, the current value of the soft limit for the specified resource
-is printed, unless the <samp>-H</samp> option is supplied.
+is printed, unless the <samp class="option">-H</samp> option is supplied.
When more than one
resource is specified, the limit name and unit, if appropriate,
are printed before the value.
-When setting new limits, if neither <samp>-H</samp> nor <samp>-S</samp> is supplied,
+When setting new limits, if neither <samp class="option">-H</samp> nor <samp class="option">-S</samp> is supplied,
both the hard and soft limits are set.
-If no option is given, then <samp>-f</samp> is assumed. Values are in 1024-byte
+If no option is given, then <samp class="option">-f</samp> is assumed. Values are in 1024-byte
increments, except for
-<samp>-t</samp>, which is in seconds;
-<samp>-R</samp>, which is in microseconds;
-<samp>-p</samp>, which is in units of 512-byte blocks;
-<samp>-P</samp>,
-<samp>-T</samp>,
-<samp>-b</samp>,
-<samp>-k</samp>,
-<samp>-n</samp> and <samp>-u</samp>, which are unscaled values;
-and, when in <small>POSIX</small> Mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>),
-<samp>-c</samp> and <samp>-f</samp>, which are in 512-byte increments.
+<samp class="option">-t</samp>, which is in seconds;
+<samp class="option">-R</samp>, which is in microseconds;
+<samp class="option">-p</samp>, which is in units of 512-byte blocks;
+<samp class="option">-P</samp>,
+<samp class="option">-T</samp>,
+<samp class="option">-b</samp>,
+<samp class="option">-k</samp>,
+<samp class="option">-n</samp> and <samp class="option">-u</samp>, which are unscaled values;
+and, when in <small class="sc">POSIX</small> Mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>),
+<samp class="option">-c</samp> and <samp class="option">-f</samp>, which are in 512-byte increments.
</p>
<p>The return status is zero unless an invalid option or argument is supplied,
or an error occurs while setting a new limit.
</p>
</dd>
-<dt id='index-unalias'><span><code>unalias</code><a href='#index-unalias' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-unalias"></a><span><code class="code">unalias</code><a class="copiable-link" href="#index-unalias"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">unalias [-a] [<var>name</var> … ]
+<pre class="example-preformatted">unalias [-a] [<var class="var">name</var> ... ]
</pre></div>
-<p>Remove each <var>name</var> from the list of aliases. If <samp>-a</samp> is
+<p>Remove each <var class="var">name</var> from the list of aliases. If <samp class="option">-a</samp> is
supplied, all aliases are removed.
-Aliases are described in <a href="#Aliases">Aliases</a>.
+Aliases are described in <a class="ref" href="#Aliases">Aliases</a>.
</p></dd>
</dl>
<hr>
</div>
-<div class="section" id="Modifying-Shell-Behavior">
-<div class="header">
+<div class="section-level-extent" id="Modifying-Shell-Behavior">
+<div class="nav-panel">
<p>
Next: <a href="#Special-Builtins" accesskey="n" rel="next">Special Builtins</a>, Previous: <a href="#Bash-Builtins" accesskey="p" rel="prev">Bash Builtin Commands</a>, Up: <a href="#Shell-Builtin-Commands" accesskey="u" rel="up">Shell Builtin Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Modifying-Shell-Behavior-1"></span><h3 class="section">4.3 Modifying Shell Behavior</h3>
+<h3 class="section" id="Modifying-Shell-Behavior-1"><span>4.3 Modifying Shell Behavior<a class="copiable-link" href="#Modifying-Shell-Behavior-1"> ¶</a></span></h3>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#The-Set-Builtin" accesskey="1">The Set Builtin</a></li>
<li><a href="#The-Shopt-Builtin" accesskey="2">The Shopt Builtin</a></li>
</ul>
<hr>
-<div class="subsection" id="The-Set-Builtin">
-<div class="header">
+<div class="subsection-level-extent" id="The-Set-Builtin">
+<div class="nav-panel">
<p>
Next: <a href="#The-Shopt-Builtin" accesskey="n" rel="next">The Shopt Builtin</a>, Up: <a href="#Modifying-Shell-Behavior" accesskey="u" rel="up">Modifying Shell Behavior</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="The-Set-Builtin-1"></span><h4 class="subsection">4.3.1 The Set Builtin</h4>
+<h4 class="subsection" id="The-Set-Builtin-1"><span>4.3.1 The Set Builtin<a class="copiable-link" href="#The-Set-Builtin-1"> ¶</a></span></h4>
-<p>This builtin is so complicated that it deserves its own section. <code>set</code>
+<p>This builtin is so complicated that it deserves its own section. <code class="code">set</code>
allows you to change the values of shell options and set the positional
parameters, or to display the names and values of shell variables.
</p>
-<dl compact="compact">
-<dt id='index-set'><span><code>set</code><a href='#index-set' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-set"></a><span><code class="code">set</code><a class="copiable-link" href="#index-set"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">set [-abefhkmnptuvxBCEHPT] [-o <var>option-name</var>] [--] [-] [<var>argument</var> …]
-set [+abefhkmnptuvxBCEHPT] [+o <var>option-name</var>] [--] [-] [<var>argument</var> …]
+<pre class="example-preformatted">set [-abefhkmnptuvxBCEHPT] [-o <var class="var">option-name</var>] [--] [-] [<var class="var">argument</var> ...]
+set [+abefhkmnptuvxBCEHPT] [+o <var class="var">option-name</var>] [--] [-] [<var class="var">argument</var> ...]
set -o
set +o
</pre></div>
-<p>If no options or arguments are supplied, <code>set</code> displays the names
+<p>If no options or arguments are supplied, <code class="code">set</code> displays the names
and values of all shell variables and functions, sorted according to the
current locale, in a format that may be reused as input
for setting or resetting the currently-set variables.
Read-only variables cannot be reset.
-In <small>POSIX</small> mode, only shell variables are listed.
+In <small class="sc">POSIX</small> mode, only shell variables are listed.
</p>
<p>When options are supplied, they set or unset shell attributes.
Options, if specified, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-a</code></span></dt>
+<dl class="table">
+<dt><code class="code">-a</code></dt>
<dd><p>Each variable or function that is created or modified is given the
export attribute and marked for export to the environment of
subsequent commands.
</p>
</dd>
-<dt><span><code>-b</code></span></dt>
+<dt><code class="code">-b</code></dt>
<dd><p>Cause the status of terminated background jobs to be reported
immediately, rather than before printing the next primary prompt.
</p>
</dd>
-<dt><span><code>-e</code></span></dt>
+<dt><code class="code">-e</code></dt>
<dd><p>Exit immediately if
-a pipeline (see <a href="#Pipelines">Pipelines</a>), which may consist of a single simple command
-(see <a href="#Simple-Commands">Simple Commands</a>),
-a list (see <a href="#Lists">Lists of Commands</a>),
-or a compound command (see <a href="#Compound-Commands">Compound Commands</a>)
+a pipeline (see <a class="pxref" href="#Pipelines">Pipelines</a>), which may consist of a single simple command
+(see <a class="pxref" href="#Simple-Commands">Simple Commands</a>),
+a list (see <a class="pxref" href="#Lists">Lists of Commands</a>),
+or a compound command (see <a class="pxref" href="#Compound-Commands">Compound Commands</a>)
returns a non-zero status.
The shell does not exit if the command that fails is part of the
-command list immediately following a <code>while</code> or <code>until</code> keyword,
-part of the test in an <code>if</code> statement,
-part of any command executed in a <code>&&</code> or <code>||</code> list except
-the command following the final <code>&&</code> or <code>||</code>,
+command list immediately following a <code class="code">while</code> or <code class="code">until</code> keyword,
+part of the test in an <code class="code">if</code> statement,
+part of any command executed in a <code class="code">&&</code> or <code class="code">||</code> list except
+the command following the final <code class="code">&&</code> or <code class="code">||</code>,
any command in a pipeline but the last,
-or if the command’s return status is being inverted with <code>!</code>.
+or if the command’s return status is being inverted with <code class="code">!</code>.
If a compound command other than a subshell
returns a non-zero status because a command failed
-while <samp>-e</samp> was being ignored, the shell does not exit.
-A trap on <code>ERR</code>, if set, is executed before the shell exits.
+while <samp class="option">-e</samp> was being ignored, the shell does not exit.
+A trap on <code class="code">ERR</code>, if set, is executed before the shell exits.
</p>
<p>This option applies to the shell environment and each subshell environment
-separately (see <a href="#Command-Execution-Environment">Command Execution Environment</a>), and may cause
+separately (see <a class="pxref" href="#Command-Execution-Environment">Command Execution Environment</a>), and may cause
subshells to exit before executing all the commands in the subshell.
</p>
<p>If a compound command or shell function executes in a context where
-<samp>-e</samp> is being ignored,
+<samp class="option">-e</samp> is being ignored,
none of the commands executed within the compound command or function body
-will be affected by the <samp>-e</samp> setting, even if <samp>-e</samp> is set
+will be affected by the <samp class="option">-e</samp> setting, even if <samp class="option">-e</samp> is set
and a command returns a failure status.
-If a compound command or shell function sets <samp>-e</samp> while executing in
-a context where <samp>-e</samp> is ignored, that setting will not have any
+If a compound command or shell function sets <samp class="option">-e</samp> while executing in
+a context where <samp class="option">-e</samp> is ignored, that setting will not have any
effect until the compound command or the command containing the function
call completes.
</p>
</dd>
-<dt><span><code>-f</code></span></dt>
+<dt><code class="code">-f</code></dt>
<dd><p>Disable filename expansion (globbing).
</p>
</dd>
-<dt><span><code>-h</code></span></dt>
+<dt><code class="code">-h</code></dt>
<dd><p>Locate and remember (hash) commands as they are looked up for execution.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>-k</code></span></dt>
+<dt><code class="code">-k</code></dt>
<dd><p>All arguments in the form of assignment statements are placed
in the environment for a command, not just those that precede
the command name.
</p>
</dd>
-<dt><span><code>-m</code></span></dt>
-<dd><p>Job control is enabled (see <a href="#Job-Control">Job Control</a>).
+<dt><code class="code">-m</code></dt>
+<dd><p>Job control is enabled (see <a class="pxref" href="#Job-Control">Job Control</a>).
All processes run in a separate process group.
When a background job completes, the shell prints a line
containing its exit status.
</p>
</dd>
-<dt><span><code>-n</code></span></dt>
+<dt><code class="code">-n</code></dt>
<dd><p>Read commands but do not execute them.
This may be used to check a script for syntax errors.
This option is ignored by interactive shells.
</p>
</dd>
-<dt><span><code>-o <var>option-name</var></code></span></dt>
+<dt><code class="code">-o <var class="var">option-name</var></code></dt>
<dd>
-<p>Set the option corresponding to <var>option-name</var>.
-If <samp>-o</samp> is supplied with no <var>option-name</var>,
-<code>set</code> prints the current shell options settings.
-If <samp>+o</samp> is supplied with no <var>option-name</var>,
-<code>set</code> prints a series of
-<code>set</code>
+<p>Set the option corresponding to <var class="var">option-name</var>.
+If <samp class="option">-o</samp> is supplied with no <var class="var">option-name</var>,
+<code class="code">set</code> prints the current shell options settings.
+If <samp class="option">+o</samp> is supplied with no <var class="var">option-name</var>,
+<code class="code">set</code> prints a series of
+<code class="code">set</code>
commands to recreate the current option settings
on the standard output.
Valid option names are:
</p>
-<dl compact="compact">
-<dt><span><code>allexport</code></span></dt>
-<dd><p>Same as <code>-a</code>.
+<dl class="table">
+<dt><code class="code">allexport</code></dt>
+<dd><p>Same as <code class="code">-a</code>.
</p>
</dd>
-<dt><span><code>braceexpand</code></span></dt>
-<dd><p>Same as <code>-B</code>.
+<dt><code class="code">braceexpand</code></dt>
+<dd><p>Same as <code class="code">-B</code>.
</p>
</dd>
-<dt><span><code>emacs</code></span></dt>
-<dd><p>Use an <code>emacs</code>-style line editing interface (see <a href="#Command-Line-Editing">Command Line Editing</a>).
-This also affects the editing interface used for <code>read -e</code>.
+<dt><code class="code">emacs</code></dt>
+<dd><p>Use an <code class="code">emacs</code>-style line editing interface (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>).
+This also affects the editing interface used for <code class="code">read -e</code>.
</p>
</dd>
-<dt><span><code>errexit</code></span></dt>
-<dd><p>Same as <code>-e</code>.
+<dt><code class="code">errexit</code></dt>
+<dd><p>Same as <code class="code">-e</code>.
</p>
</dd>
-<dt><span><code>errtrace</code></span></dt>
-<dd><p>Same as <code>-E</code>.
+<dt><code class="code">errtrace</code></dt>
+<dd><p>Same as <code class="code">-E</code>.
</p>
</dd>
-<dt><span><code>functrace</code></span></dt>
-<dd><p>Same as <code>-T</code>.
+<dt><code class="code">functrace</code></dt>
+<dd><p>Same as <code class="code">-T</code>.
</p>
</dd>
-<dt><span><code>hashall</code></span></dt>
-<dd><p>Same as <code>-h</code>.
+<dt><code class="code">hashall</code></dt>
+<dd><p>Same as <code class="code">-h</code>.
</p>
</dd>
-<dt><span><code>histexpand</code></span></dt>
-<dd><p>Same as <code>-H</code>.
+<dt><code class="code">histexpand</code></dt>
+<dd><p>Same as <code class="code">-H</code>.
</p>
</dd>
-<dt><span><code>history</code></span></dt>
-<dd><p>Enable command history, as described in <a href="#Bash-History-Facilities">Bash History Facilities</a>.
+<dt><code class="code">history</code></dt>
+<dd><p>Enable command history, as described in <a class="ref" href="#Bash-History-Facilities">Bash History Facilities</a>.
This option is on by default in interactive shells.
</p>
</dd>
-<dt><span><code>ignoreeof</code></span></dt>
+<dt><code class="code">ignoreeof</code></dt>
<dd><p>An interactive shell will not exit upon reading EOF.
</p>
</dd>
-<dt><span><code>keyword</code></span></dt>
-<dd><p>Same as <code>-k</code>.
+<dt><code class="code">keyword</code></dt>
+<dd><p>Same as <code class="code">-k</code>.
</p>
</dd>
-<dt><span><code>monitor</code></span></dt>
-<dd><p>Same as <code>-m</code>.
+<dt><code class="code">monitor</code></dt>
+<dd><p>Same as <code class="code">-m</code>.
</p>
</dd>
-<dt><span><code>noclobber</code></span></dt>
-<dd><p>Same as <code>-C</code>.
+<dt><code class="code">noclobber</code></dt>
+<dd><p>Same as <code class="code">-C</code>.
</p>
</dd>
-<dt><span><code>noexec</code></span></dt>
-<dd><p>Same as <code>-n</code>.
+<dt><code class="code">noexec</code></dt>
+<dd><p>Same as <code class="code">-n</code>.
</p>
</dd>
-<dt><span><code>noglob</code></span></dt>
-<dd><p>Same as <code>-f</code>.
+<dt><code class="code">noglob</code></dt>
+<dd><p>Same as <code class="code">-f</code>.
</p>
</dd>
-<dt><span><code>nolog</code></span></dt>
+<dt><code class="code">nolog</code></dt>
<dd><p>Currently ignored.
</p>
</dd>
-<dt><span><code>notify</code></span></dt>
-<dd><p>Same as <code>-b</code>.
+<dt><code class="code">notify</code></dt>
+<dd><p>Same as <code class="code">-b</code>.
</p>
</dd>
-<dt><span><code>nounset</code></span></dt>
-<dd><p>Same as <code>-u</code>.
+<dt><code class="code">nounset</code></dt>
+<dd><p>Same as <code class="code">-u</code>.
</p>
</dd>
-<dt><span><code>onecmd</code></span></dt>
-<dd><p>Same as <code>-t</code>.
+<dt><code class="code">onecmd</code></dt>
+<dd><p>Same as <code class="code">-t</code>.
</p>
</dd>
-<dt><span><code>physical</code></span></dt>
-<dd><p>Same as <code>-P</code>.
+<dt><code class="code">physical</code></dt>
+<dd><p>Same as <code class="code">-P</code>.
</p>
</dd>
-<dt><span><code>pipefail</code></span></dt>
+<dt><code class="code">pipefail</code></dt>
<dd><p>If set, the return value of a pipeline is the value of the last
(rightmost) command to exit with a non-zero status, or zero if all
commands in the pipeline exit successfully.
This option is disabled by default.
</p>
</dd>
-<dt><span><code>posix</code></span></dt>
+<dt><code class="code">posix</code></dt>
<dd><p>Change the behavior of Bash where the default operation differs
-from the <small>POSIX</small> standard to match the standard
-(see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>).
+from the <small class="sc">POSIX</small> standard to match the standard
+(see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>).
This is intended to make Bash behave as a strict superset of that
standard.
</p>
</dd>
-<dt><span><code>privileged</code></span></dt>
-<dd><p>Same as <code>-p</code>.
+<dt><code class="code">privileged</code></dt>
+<dd><p>Same as <code class="code">-p</code>.
</p>
</dd>
-<dt><span><code>verbose</code></span></dt>
-<dd><p>Same as <code>-v</code>.
+<dt><code class="code">verbose</code></dt>
+<dd><p>Same as <code class="code">-v</code>.
</p>
</dd>
-<dt><span><code>vi</code></span></dt>
-<dd><p>Use a <code>vi</code>-style line editing interface.
-This also affects the editing interface used for <code>read -e</code>.
+<dt><code class="code">vi</code></dt>
+<dd><p>Use a <code class="code">vi</code>-style line editing interface.
+This also affects the editing interface used for <code class="code">read -e</code>.
</p>
</dd>
-<dt><span><code>xtrace</code></span></dt>
-<dd><p>Same as <code>-x</code>.
+<dt><code class="code">xtrace</code></dt>
+<dd><p>Same as <code class="code">-x</code>.
</p></dd>
</dl>
</dd>
-<dt><span><code>-p</code></span></dt>
+<dt><code class="code">-p</code></dt>
<dd><p>Turn on privileged mode.
-In this mode, the <code>$BASH_ENV</code> and <code>$ENV</code> files are not
+In this mode, the <code class="env">$BASH_ENV</code> and <code class="env">$ENV</code> files are not
processed, shell functions are not inherited from the environment,
-and the <code>SHELLOPTS</code>, <code>BASHOPTS</code>, <code>CDPATH</code> and <code>GLOBIGNORE</code>
+and the <code class="env">SHELLOPTS</code>, <code class="env">BASHOPTS</code>, <code class="env">CDPATH</code> and <code class="env">GLOBIGNORE</code>
variables, if they appear in the environment, are ignored.
If the shell is started with the effective user (group) id not equal to the
-real user (group) id, and the <samp>-p</samp> option is not supplied, these actions
+real user (group) id, and the <samp class="option">-p</samp> option is not supplied, these actions
are taken and the effective user id is set to the real user id.
-If the <samp>-p</samp> option is supplied at startup, the effective user id is
+If the <samp class="option">-p</samp> option is supplied at startup, the effective user id is
not reset.
Turning this option off causes the effective user
and group ids to be set to the real user and group ids.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
-<dd><p>Enable restricted shell mode (see <a href="#The-Restricted-Shell">The Restricted Shell</a>).
+<dt><code class="code">-r</code></dt>
+<dd><p>Enable restricted shell mode (see <a class="pxref" href="#The-Restricted-Shell">The Restricted Shell</a>).
This option cannot be unset once it has been set.
</p>
</dd>
-<dt><span><code>-t</code></span></dt>
+<dt><code class="code">-t</code></dt>
<dd><p>Exit after reading and executing one command.
</p>
</dd>
-<dt><span><code>-u</code></span></dt>
+<dt><code class="code">-u</code></dt>
<dd><p>Treat unset variables and parameters other than the special parameters
-‘<samp>@</samp>’ or ‘<samp>*</samp>’,
-or array variables subscripted with ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
+or array variables subscripted with ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
as an error when performing parameter expansion.
An error message will be written to the standard error, and a non-interactive
shell will exit.
</p>
</dd>
-<dt><span><code>-v</code></span></dt>
+<dt><code class="code">-v</code></dt>
<dd><p>Print shell input lines as they are read.
</p>
</dd>
-<dt><span><code>-x</code></span></dt>
-<dd><p>Print a trace of simple commands, <code>for</code> commands, <code>case</code>
-commands, <code>select</code> commands, and arithmetic <code>for</code> commands
+<dt><code class="code">-x</code></dt>
+<dd><p>Print a trace of simple commands, <code class="code">for</code> commands, <code class="code">case</code>
+commands, <code class="code">select</code> commands, and arithmetic <code class="code">for</code> commands
and their arguments or associated word lists to standard error
after they are expanded and before they are executed.
-The shell prints the expanded value of the <code>PS4</code> variable before
+The shell prints the expanded value of the <code class="env">PS4</code> variable before
the command and its expanded arguments.
</p>
</dd>
-<dt><span><code>-B</code></span></dt>
-<dd><p>The shell will perform brace expansion (see <a href="#Brace-Expansion">Brace Expansion</a>).
+<dt><code class="code">-B</code></dt>
+<dd><p>The shell will perform brace expansion (see <a class="pxref" href="#Brace-Expansion">Brace Expansion</a>).
This option is on by default.
</p>
</dd>
-<dt><span><code>-C</code></span></dt>
-<dd><p>Prevent output redirection using ‘<samp>></samp>’, ‘<samp>>&</samp>’, and ‘<samp><></samp>’
+<dt><code class="code">-C</code></dt>
+<dd><p>Prevent output redirection using ‘<samp class="samp">></samp>’, ‘<samp class="samp">>&</samp>’, and ‘<samp class="samp"><></samp>’
from overwriting existing files.
</p>
</dd>
-<dt><span><code>-E</code></span></dt>
-<dd><p>If set, any trap on <code>ERR</code> is inherited by shell functions, command
+<dt><code class="code">-E</code></dt>
+<dd><p>If set, any trap on <code class="code">ERR</code> is inherited by shell functions, command
substitutions, and commands executed in a subshell environment.
-The <code>ERR</code> trap is normally not inherited in such cases.
+The <code class="code">ERR</code> trap is normally not inherited in such cases.
</p>
</dd>
-<dt><span><code>-H</code></span></dt>
-<dd><p>Enable ‘<samp>!</samp>’ style history substitution (see <a href="#History-Interaction">History Expansion</a>).
+<dt><code class="code">-H</code></dt>
+<dd><p>Enable ‘<samp class="samp">!</samp>’ style history substitution (see <a class="pxref" href="#History-Interaction">History Expansion</a>).
This option is on by default for interactive shells.
</p>
</dd>
-<dt><span><code>-P</code></span></dt>
+<dt><code class="code">-P</code></dt>
<dd><p>If set, do not resolve symbolic links when performing commands such as
-<code>cd</code> which change the current directory. The physical directory
+<code class="code">cd</code> which change the current directory. The physical directory
is used instead. By default, Bash follows
the logical chain of directories when performing commands
which change the current directory.
</p>
-<p>For example, if <samp>/usr/sys</samp> is a symbolic link to <samp>/usr/local/sys</samp>
+<p>For example, if <samp class="file">/usr/sys</samp> is a symbolic link to <samp class="file">/usr/local/sys</samp>
then:
</p><div class="example">
-<pre class="example">$ cd /usr/sys; echo $PWD
+<pre class="example-preformatted">$ cd /usr/sys; echo $PWD
/usr/sys
$ cd ..; pwd
/usr
</pre></div>
-<p>If <code>set -P</code> is on, then:
+<p>If <code class="code">set -P</code> is on, then:
</p><div class="example">
-<pre class="example">$ cd /usr/sys; echo $PWD
+<pre class="example-preformatted">$ cd /usr/sys; echo $PWD
/usr/local/sys
$ cd ..; pwd
/usr/local
</pre></div>
</dd>
-<dt><span><code>-T</code></span></dt>
-<dd><p>If set, any trap on <code>DEBUG</code> and <code>RETURN</code> are inherited by
+<dt><code class="code">-T</code></dt>
+<dd><p>If set, any trap on <code class="code">DEBUG</code> and <code class="code">RETURN</code> are inherited by
shell functions, command substitutions, and commands executed
in a subshell environment.
-The <code>DEBUG</code> and <code>RETURN</code> traps are normally not inherited
+The <code class="code">DEBUG</code> and <code class="code">RETURN</code> traps are normally not inherited
in such cases.
</p>
</dd>
-<dt><span><code>--</code></span></dt>
+<dt><code class="code">--</code></dt>
<dd><p>If no arguments follow this option, then the positional parameters are
unset. Otherwise, the positional parameters are set to the
-<var>arguments</var>, even if some of them begin with a ‘<samp>-</samp>’.
+<var class="var">arguments</var>, even if some of them begin with a ‘<samp class="samp">-</samp>’.
</p>
</dd>
-<dt><span><code>-</code></span></dt>
-<dd><p>Signal the end of options, cause all remaining <var>arguments</var>
-to be assigned to the positional parameters. The <samp>-x</samp>
-and <samp>-v</samp> options are turned off.
+<dt><code class="code">-</code></dt>
+<dd><p>Signal the end of options, cause all remaining <var class="var">arguments</var>
+to be assigned to the positional parameters. The <samp class="option">-x</samp>
+and <samp class="option">-v</samp> options are turned off.
If there are no arguments, the positional parameters remain unchanged.
</p></dd>
</dl>
-<p>Using ‘<samp>+</samp>’ rather than ‘<samp>-</samp>’ causes these options to be
+<p>Using ‘<samp class="samp">+</samp>’ rather than ‘<samp class="samp">-</samp>’ causes these options to be
turned off. The options can also be used upon invocation of the
-shell. The current set of options may be found in <code>$-</code>.
+shell. The current set of options may be found in <code class="code">$-</code>.
</p>
-<p>The remaining N <var>arguments</var> are positional parameters and are
-assigned, in order, to <code>$1</code>, <code>$2</code>, … <code>$N</code>.
-The special parameter <code>#</code> is set to N.
+<p>The remaining N <var class="var">arguments</var> are positional parameters and are
+assigned, in order, to <code class="code">$1</code>, <code class="code">$2</code>, … <code class="code">$N</code>.
+The special parameter <code class="code">#</code> is set to N.
</p>
<p>The return status is always zero unless an invalid option is supplied.
</p></dd>
<hr>
</div>
-<div class="subsection" id="The-Shopt-Builtin">
-<div class="header">
+<div class="subsection-level-extent" id="The-Shopt-Builtin">
+<div class="nav-panel">
<p>
Previous: <a href="#The-Set-Builtin" accesskey="p" rel="prev">The Set Builtin</a>, Up: <a href="#Modifying-Shell-Behavior" accesskey="u" rel="up">Modifying Shell Behavior</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="The-Shopt-Builtin-1"></span><h4 class="subsection">4.3.2 The Shopt Builtin</h4>
+<h4 class="subsection" id="The-Shopt-Builtin-1"><span>4.3.2 The Shopt Builtin<a class="copiable-link" href="#The-Shopt-Builtin-1"> ¶</a></span></h4>
<p>This builtin allows you to change additional shell optional behavior.
</p>
-<dl compact="compact">
-<dt id='index-shopt'><span><code>shopt</code><a href='#index-shopt' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-shopt"></a><span><code class="code">shopt</code><a class="copiable-link" href="#index-shopt"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">shopt [-pqsu] [-o] [<var>optname</var> …]
+<pre class="example-preformatted">shopt [-pqsu] [-o] [<var class="var">optname</var> ...]
</pre></div>
<p>Toggle the values of settings controlling optional shell behavior.
The settings can be either those listed below, or, if the
-<samp>-o</samp> option is used, those available with the <samp>-o</samp>
-option to the <code>set</code> builtin command (see <a href="#The-Set-Builtin">The Set Builtin</a>).
-With no options, or with the <samp>-p</samp> option, a list of all settable
+<samp class="option">-o</samp> option is used, those available with the <samp class="option">-o</samp>
+option to the <code class="code">set</code> builtin command (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
+With no options, or with the <samp class="option">-p</samp> option, a list of all settable
options is displayed, with an indication of whether or not each is set;
-if <var>optname</var>s are supplied, the output is restricted to those options.
-The <samp>-p</samp> option causes output to be displayed in a form that
+if <var class="var">optname</var>s are supplied, the output is restricted to those options.
+The <samp class="option">-p</samp> option causes output to be displayed in a form that
may be reused as input.
Other options have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-s</code></span></dt>
-<dd><p>Enable (set) each <var>optname</var>.
+<dl class="table">
+<dt><code class="code">-s</code></dt>
+<dd><p>Enable (set) each <var class="var">optname</var>.
</p>
</dd>
-<dt><span><code>-u</code></span></dt>
-<dd><p>Disable (unset) each <var>optname</var>.
+<dt><code class="code">-u</code></dt>
+<dd><p>Disable (unset) each <var class="var">optname</var>.
</p>
</dd>
-<dt><span><code>-q</code></span></dt>
+<dt><code class="code">-q</code></dt>
<dd><p>Suppresses normal output; the return status
-indicates whether the <var>optname</var> is set or unset.
-If multiple <var>optname</var> arguments are given with <samp>-q</samp>,
-the return status is zero if all <var>optname</var>s are enabled;
+indicates whether the <var class="var">optname</var> is set or unset.
+If multiple <var class="var">optname</var> arguments are given with <samp class="option">-q</samp>,
+the return status is zero if all <var class="var">optname</var>s are enabled;
non-zero otherwise.
</p>
</dd>
-<dt><span><code>-o</code></span></dt>
+<dt><code class="code">-o</code></dt>
<dd><p>Restricts the values of
-<var>optname</var> to be those defined for the <samp>-o</samp> option to the
-<code>set</code> builtin (see <a href="#The-Set-Builtin">The Set Builtin</a>).
+<var class="var">optname</var> to be those defined for the <samp class="option">-o</samp> option to the
+<code class="code">set</code> builtin (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
</p></dd>
</dl>
-<p>If either <samp>-s</samp> or <samp>-u</samp>
-is used with no <var>optname</var> arguments, <code>shopt</code> shows only
+<p>If either <samp class="option">-s</samp> or <samp class="option">-u</samp>
+is used with no <var class="var">optname</var> arguments, <code class="code">shopt</code> shows only
those options which are set or unset, respectively.
</p>
-<p>Unless otherwise noted, the <code>shopt</code> options are disabled (off)
+<p>Unless otherwise noted, the <code class="code">shopt</code> options are disabled (off)
by default.
</p>
-<p>The return status when listing options is zero if all <var>optname</var>s
+<p>The return status when listing options is zero if all <var class="var">optname</var>s
are enabled, non-zero otherwise. When setting or unsetting options,
-the return status is zero unless an <var>optname</var> is not a valid shell
+the return status is zero unless an <var class="var">optname</var> is not a valid shell
option.
</p>
-<p>The list of <code>shopt</code> options is:
-</p><dl compact="compact">
-<dt><span><code>array_expand_once</code></span></dt>
+<p>The list of <code class="code">shopt</code> options is:
+</p><dl class="table">
+<dt><code class="code">array_expand_once</code></dt>
<dd><p>If set, the shell suppresses multiple evaluation of
associative and indexed array subscripts
during arithmetic expression evaluation, while executing
and while executing builtins that perform array dereferencing.
</p>
</dd>
-<dt><span><code>assoc_expand_once</code></span></dt>
-<dd><p>Deprecated; a synonym for <code>array_expand_once</code>.
+<dt><code class="code">assoc_expand_once</code></dt>
+<dd><p>Deprecated; a synonym for <code class="code">array_expand_once</code>.
</p>
</dd>
-<dt><span><code>autocd</code></span></dt>
+<dt><code class="code">autocd</code></dt>
<dd><p>If set, a command name that is the name of a directory is executed as if
-it were the argument to the <code>cd</code> command.
+it were the argument to the <code class="code">cd</code> command.
This option is only used by interactive shells.
</p>
</dd>
-<dt><span><code>cdable_vars</code></span></dt>
-<dd><p>If this is set, an argument to the <code>cd</code> builtin command that
+<dt><code class="code">cdable_vars</code></dt>
+<dd><p>If this is set, an argument to the <code class="code">cd</code> builtin command that
is not a directory is assumed to be the name of a variable whose
value is the directory to change to.
</p>
</dd>
-<dt><span><code>cdspell</code></span></dt>
+<dt><code class="code">cdspell</code></dt>
<dd><p>If set, minor errors in the spelling of a directory component in a
-<code>cd</code> command will be corrected.
+<code class="code">cd</code> command will be corrected.
The errors checked for are transposed characters,
a missing character, and a character too many.
If a correction is found, the corrected path is printed,
This option is only used by interactive shells.
</p>
</dd>
-<dt><span><code>checkhash</code></span></dt>
+<dt><code class="code">checkhash</code></dt>
<dd><p>If this is set, Bash checks that a command found in the hash
table exists before trying to execute it. If a hashed command no
longer exists, a normal path search is performed.
</p>
</dd>
-<dt><span><code>checkjobs</code></span></dt>
+<dt><code class="code">checkjobs</code></dt>
<dd><p>If set, Bash lists the status of any stopped and running jobs before
exiting an interactive shell. If any jobs are running, this causes
the exit to be deferred until a second exit is attempted without an
-intervening command (see <a href="#Job-Control">Job Control</a>).
+intervening command (see <a class="pxref" href="#Job-Control">Job Control</a>).
The shell always postpones exiting if any jobs are stopped.
</p>
</dd>
-<dt><span><code>checkwinsize</code></span></dt>
+<dt><code class="code">checkwinsize</code></dt>
<dd><p>If set, Bash checks the window size after each external (non-builtin)
command and, if necessary, updates the values of
-<code>LINES</code> and <code>COLUMNS</code>.
+<code class="env">LINES</code> and <code class="env">COLUMNS</code>.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>cmdhist</code></span></dt>
+<dt><code class="code">cmdhist</code></dt>
<dd><p>If set, Bash
attempts to save all lines of a multiple-line
command in the same history entry. This allows
easy re-editing of multi-line commands.
This option is enabled by default, but only has an effect if command
-history is enabled (see <a href="#Bash-History-Facilities">Bash History Facilities</a>).
+history is enabled (see <a class="pxref" href="#Bash-History-Facilities">Bash History Facilities</a>).
</p>
</dd>
-<dt><span><code>compat31</code></span></dt>
-<dt><span><code>compat32</code></span></dt>
-<dt><span><code>compat40</code></span></dt>
-<dt><span><code>compat41</code></span></dt>
-<dt><span><code>compat42</code></span></dt>
-<dt><span><code>compat43</code></span></dt>
-<dt><span><code>compat44</code></span></dt>
+<dt><code class="code">compat31</code></dt>
+<dt><code class="code">compat32</code></dt>
+<dt><code class="code">compat40</code></dt>
+<dt><code class="code">compat41</code></dt>
+<dt><code class="code">compat42</code></dt>
+<dt><code class="code">compat43</code></dt>
+<dt><code class="code">compat44</code></dt>
<dd><p>These control aspects of the shell’s compatibility mode
-(see <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>).
+(see <a class="pxref" href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>).
</p>
</dd>
-<dt><span><code>complete_fullquote</code></span></dt>
+<dt><code class="code">complete_fullquote</code></dt>
<dd><p>If set, Bash
quotes all shell metacharacters in filenames and directory names when
performing completion.
versions through 4.2.
</p>
</dd>
-<dt><span><code>direxpand</code></span></dt>
+<dt><code class="code">direxpand</code></dt>
<dd><p>If set, Bash
replaces directory names with the results of word expansion when performing
filename completion. This changes the contents of the Readline editing
If not set, Bash attempts to preserve what the user typed.
</p>
</dd>
-<dt><span><code>dirspell</code></span></dt>
+<dt><code class="code">dirspell</code></dt>
<dd><p>If set, Bash
attempts spelling correction on directory names during word completion
if the directory name initially supplied does not exist.
</p>
</dd>
-<dt><span><code>dotglob</code></span></dt>
+<dt><code class="code">dotglob</code></dt>
<dd><p>If set, Bash includes filenames beginning with a ‘.’ in
the results of filename expansion.
-The filenames ‘<samp>.</samp>’ and ‘<samp>..</samp>’ must always be matched explicitly,
-even if <code>dotglob</code> is set.
+The filenames ‘<samp class="samp">.</samp>’ and ‘<samp class="samp">..</samp>’ must always be matched explicitly,
+even if <code class="code">dotglob</code> is set.
</p>
</dd>
-<dt><span><code>execfail</code></span></dt>
+<dt><code class="code">execfail</code></dt>
<dd><p>If this is set, a non-interactive shell will not exit if
-it cannot execute the file specified as an argument to the <code>exec</code>
-builtin command. An interactive shell does not exit if <code>exec</code>
+it cannot execute the file specified as an argument to the <code class="code">exec</code>
+builtin command. An interactive shell does not exit if <code class="code">exec</code>
fails.
</p>
</dd>
-<dt><span><code>expand_aliases</code></span></dt>
+<dt><code class="code">expand_aliases</code></dt>
<dd><p>If set, aliases are expanded as described below under Aliases,
-<a href="#Aliases">Aliases</a>.
+<a class="ref" href="#Aliases">Aliases</a>.
This option is enabled by default for interactive shells.
</p>
</dd>
-<dt><span><code>extdebug</code></span></dt>
+<dt><code class="code">extdebug</code></dt>
<dd><p>If set at shell invocation,
or in a shell startup file,
arrange to execute the debugger profile
-before the shell starts, identical to the <samp>--debugger</samp> option.
+before the shell starts, identical to the <samp class="option">--debugger</samp> option.
If set after invocation, behavior intended for use by debuggers is enabled:
</p>
-<ol>
-<li> The <samp>-F</samp> option to the <code>declare</code> builtin (see <a href="#Bash-Builtins">Bash Builtin Commands</a>)
+<ol class="enumerate">
+<li> The <samp class="option">-F</samp> option to the <code class="code">declare</code> builtin (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>)
displays the source file name and line number corresponding to each function
name supplied as an argument.
-</li><li> If the command run by the <code>DEBUG</code> trap returns a non-zero value, the
+</li><li> If the command run by the <code class="code">DEBUG</code> trap returns a non-zero value, the
next command is skipped and not executed.
-</li><li> If the command run by the <code>DEBUG</code> trap returns a value of 2, and the
+</li><li> If the command run by the <code class="code">DEBUG</code> trap returns a value of 2, and the
shell is executing in a subroutine (a shell function or a shell script
-executed by the <code>.</code> or <code>source</code> builtins), the shell simulates
-a call to <code>return</code>.
+executed by the <code class="code">.</code> or <code class="code">source</code> builtins), the shell simulates
+a call to <code class="code">return</code>.
-</li><li> <code>BASH_ARGC</code> and <code>BASH_ARGV</code> are updated as described in their
-descriptions (see <a href="#Bash-Variables">Bash Variables</a>).
+</li><li> <code class="code">BASH_ARGC</code> and <code class="code">BASH_ARGV</code> are updated as described in their
+descriptions (see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
</li><li> Function tracing is enabled: command substitution, shell functions, and
-subshells invoked with <code>( <var>command</var> )</code> inherit the
-<code>DEBUG</code> and <code>RETURN</code> traps.
+subshells invoked with <code class="code">( <var class="var">command</var> )</code> inherit the
+<code class="code">DEBUG</code> and <code class="code">RETURN</code> traps.
</li><li> Error tracing is enabled: command substitution, shell functions, and
-subshells invoked with <code>( <var>command</var> )</code> inherit the
-<code>ERR</code> trap.
+subshells invoked with <code class="code">( <var class="var">command</var> )</code> inherit the
+<code class="code">ERR</code> trap.
</li></ol>
</dd>
-<dt><span><code>extglob</code></span></dt>
+<dt><code class="code">extglob</code></dt>
<dd><p>If set, the extended pattern matching features described above
-(see <a href="#Pattern-Matching">Pattern Matching</a>) are enabled.
+(see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>) are enabled.
</p>
</dd>
-<dt><span><code>extquote</code></span></dt>
-<dd><p>If set, <code>$'<var>string</var>'</code> and <code>$"<var>string</var>"</code> quoting is
-performed within <code>${<var>parameter</var>}</code> expansions
+<dt><code class="code">extquote</code></dt>
+<dd><p>If set, <code class="code">$'<var class="var">string</var>'</code> and <code class="code">$"<var class="var">string</var>"</code> quoting is
+performed within <code class="code">${<var class="var">parameter</var>}</code> expansions
enclosed in double quotes. This option is enabled by default.
</p>
</dd>
-<dt><span><code>failglob</code></span></dt>
+<dt><code class="code">failglob</code></dt>
<dd><p>If set, patterns which fail to match filenames during filename expansion
result in an expansion error.
</p>
</dd>
-<dt><span><code>force_fignore</code></span></dt>
-<dd><p>If set, the suffixes specified by the <code>FIGNORE</code> shell variable
+<dt><code class="code">force_fignore</code></dt>
+<dd><p>If set, the suffixes specified by the <code class="env">FIGNORE</code> shell variable
cause words to be ignored when performing word completion even if
the ignored words are the only possible completions.
-See <a href="#Bash-Variables">Bash Variables</a>, for a description of <code>FIGNORE</code>.
+See <a class="xref" href="#Bash-Variables">Bash Variables</a>, for a description of <code class="env">FIGNORE</code>.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>globasciiranges</code></span></dt>
+<dt><code class="code">globasciiranges</code></dt>
<dd><p>If set, range expressions used in pattern matching bracket expressions
-(see <a href="#Pattern-Matching">Pattern Matching</a>)
+(see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>)
behave as if in the traditional C locale when performing
comparisons. That is, the current locale’s collating sequence
is not taken into account, so
-‘<samp>b</samp>’ will not collate between ‘<samp>A</samp>’ and ‘<samp>B</samp>’,
+‘<samp class="samp">b</samp>’ will not collate between ‘<samp class="samp">A</samp>’ and ‘<samp class="samp">B</samp>’,
and upper-case and lower-case ASCII characters will collate together.
</p>
</dd>
-<dt><span><code>globskipdots</code></span></dt>
+<dt><code class="code">globskipdots</code></dt>
<dd><p>If set, filename expansion will never match the filenames
-‘<samp>.</samp>’ and ‘<samp>..</samp>’,
-even if the pattern begins with a ‘<samp>.</samp>’.
+‘<samp class="samp">.</samp>’ and ‘<samp class="samp">..</samp>’,
+even if the pattern begins with a ‘<samp class="samp">.</samp>’.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>globstar</code></span></dt>
-<dd><p>If set, the pattern ‘<samp>**</samp>’ used in a filename expansion context will
+<dt><code class="code">globstar</code></dt>
+<dd><p>If set, the pattern ‘<samp class="samp">**</samp>’ used in a filename expansion context will
match all files and zero or more directories and subdirectories.
-If the pattern is followed by a ‘<samp>/</samp>’, only directories and
+If the pattern is followed by a ‘<samp class="samp">/</samp>’, only directories and
subdirectories match.
</p>
</dd>
-<dt><span><code>gnu_errfmt</code></span></dt>
-<dd><p>If set, shell error messages are written in the standard <small>GNU</small> error
+<dt><code class="code">gnu_errfmt</code></dt>
+<dd><p>If set, shell error messages are written in the standard <small class="sc">GNU</small> error
message format.
</p>
</dd>
-<dt><span><code>histappend</code></span></dt>
+<dt><code class="code">histappend</code></dt>
<dd><p>If set, the history list is appended to the file named by the value
-of the <code>HISTFILE</code>
+of the <code class="env">HISTFILE</code>
variable when the shell exits, rather than overwriting the file.
</p>
</dd>
-<dt><span><code>histreedit</code></span></dt>
+<dt><code class="code">histreedit</code></dt>
<dd><p>If set, and Readline
is being used, a user is given the opportunity to re-edit a
failed history substitution.
</p>
</dd>
-<dt><span><code>histverify</code></span></dt>
+<dt><code class="code">histverify</code></dt>
<dd><p>If set, and Readline
is being used, the results of history substitution are not immediately
passed to the shell parser. Instead, the resulting line is loaded into
the Readline editing buffer, allowing further modification.
</p>
</dd>
-<dt><span><code>hostcomplete</code></span></dt>
+<dt><code class="code">hostcomplete</code></dt>
<dd><p>If set, and Readline is being used, Bash will attempt to perform
-hostname completion when a word containing a ‘<samp>@</samp>’ is being
-completed (see <a href="#Commands-For-Completion">Letting Readline Type For You</a>). This option is enabled
+hostname completion when a word containing a ‘<samp class="samp">@</samp>’ is being
+completed (see <a class="pxref" href="#Commands-For-Completion">Letting Readline Type For You</a>). This option is enabled
by default.
</p>
</dd>
-<dt><span><code>huponexit</code></span></dt>
-<dd><p>If set, Bash will send <code>SIGHUP</code> to all jobs when an interactive
-login shell exits (see <a href="#Signals">Signals</a>).
+<dt><code class="code">huponexit</code></dt>
+<dd><p>If set, Bash will send <code class="code">SIGHUP</code> to all jobs when an interactive
+login shell exits (see <a class="pxref" href="#Signals">Signals</a>).
</p>
</dd>
-<dt><span><code>inherit_errexit</code></span></dt>
-<dd><p>If set, command substitution inherits the value of the <code>errexit</code> option,
+<dt><code class="code">inherit_errexit</code></dt>
+<dd><p>If set, command substitution inherits the value of the <code class="code">errexit</code> option,
instead of unsetting it in the subshell environment.
-This option is enabled when <small>POSIX</small> mode is enabled.
+This option is enabled when <small class="sc">POSIX</small> mode is enabled.
</p>
</dd>
-<dt><span><code>interactive_comments</code></span></dt>
-<dd><p>Allow a word beginning with ‘<samp>#</samp>’
+<dt><code class="code">interactive_comments</code></dt>
+<dd><p>Allow a word beginning with ‘<samp class="samp">#</samp>’
to cause that word and all remaining characters on that
line to be ignored in an interactive shell.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>lastpipe</code></span></dt>
+<dt><code class="code">lastpipe</code></dt>
<dd><p>If set, and job control is not active, the shell runs the last command of
a pipeline not executed in the background in the current shell environment.
</p>
</dd>
-<dt><span><code>lithist</code></span></dt>
-<dd><p>If enabled, and the <code>cmdhist</code>
+<dt><code class="code">lithist</code></dt>
+<dd><p>If enabled, and the <code class="code">cmdhist</code>
option is enabled, multi-line commands are saved to the history with
embedded newlines rather than using semicolon separators where possible.
</p>
</dd>
-<dt><span><code>localvar_inherit</code></span></dt>
+<dt><code class="code">localvar_inherit</code></dt>
<dd><p>If set, local variables inherit the value and attributes of a variable of
the same name that exists at a previous scope before any new value is
-assigned. The <code>nameref</code> attribute is not inherited.
+assigned. The <code class="code">nameref</code> attribute is not inherited.
</p>
</dd>
-<dt><span><code>localvar_unset</code></span></dt>
-<dd><p>If set, calling <code>unset</code> on local variables in previous function scopes
+<dt><code class="code">localvar_unset</code></dt>
+<dd><p>If set, calling <code class="code">unset</code> on local variables in previous function scopes
marks them so subsequent lookups find them unset until that function
returns. This is identical to the behavior of unsetting local variables
at the current function scope.
</p>
</dd>
-<dt><span><code>login_shell</code></span></dt>
+<dt><code class="code">login_shell</code></dt>
<dd><p>The shell sets this option if it is started as a login shell
-(see <a href="#Invoking-Bash">Invoking Bash</a>).
+(see <a class="pxref" href="#Invoking-Bash">Invoking Bash</a>).
The value may not be changed.
</p>
</dd>
-<dt><span><code>mailwarn</code></span></dt>
+<dt><code class="code">mailwarn</code></dt>
<dd><p>If set, and a file that Bash is checking for mail has been
accessed since the last time it was checked, the message
-<code>"The mail in <var>mailfile</var> has been read"</code> is displayed.
+<code class="code">"The mail in <var class="var">mailfile</var> has been read"</code> is displayed.
</p>
</dd>
-<dt><span><code>no_empty_cmd_completion</code></span></dt>
+<dt><code class="code">no_empty_cmd_completion</code></dt>
<dd><p>If set, and Readline is being used, Bash will not attempt to search
-the <code>PATH</code> for possible completions when completion is attempted
+the <code class="env">PATH</code> for possible completions when completion is attempted
on an empty line.
</p>
</dd>
-<dt><span><code>nocaseglob</code></span></dt>
+<dt><code class="code">nocaseglob</code></dt>
<dd><p>If set, Bash matches filenames in a case-insensitive fashion when
performing filename expansion.
</p>
</dd>
-<dt><span><code>nocasematch</code></span></dt>
+<dt><code class="code">nocasematch</code></dt>
<dd><p>If set, Bash matches patterns in a case-insensitive fashion when
-performing matching while executing <code>case</code> or <code>[[</code>
-conditional commands (see <a href="#Conditional-Constructs">Conditional Constructs</a>,
+performing matching while executing <code class="code">case</code> or <code class="code">[[</code>
+conditional commands (see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>,
when performing pattern substitution word expansions,
or when filtering possible completions as part of programmable completion.
</p>
</dd>
-<dt><span><code>noexpand_translation</code></span></dt>
+<dt><code class="code">noexpand_translation</code></dt>
<dd><p>If set, Bash
encloses the translated results of $"..." quoting in single quotes
instead of double quotes.
If the string is not translated, this has no effect.
</p>
</dd>
-<dt><span><code>nullglob</code></span></dt>
+<dt><code class="code">nullglob</code></dt>
<dd><p>If set, filename expansion patterns which match no files
-(see <a href="#Filename-Expansion">Filename Expansion</a>)
+(see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>)
expand to nothing and are removed,
rather than expanding to themselves.
</p>
</dd>
-<dt><span><code>patsub_replacement</code></span></dt>
+<dt><code class="code">patsub_replacement</code></dt>
<dd><p>If set, Bash
-expands occurrences of ‘<samp>&</samp>’ in the replacement string of pattern
+expands occurrences of ‘<samp class="samp">&</samp>’ in the replacement string of pattern
substitution to the text matched by the pattern, as described
-above (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+above (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
This option is enabled by default.
</p>
</dd>
-<dt><span><code>progcomp</code></span></dt>
+<dt><code class="code">progcomp</code></dt>
<dd><p>If set, the programmable completion facilities
-(see <a href="#Programmable-Completion">Programmable Completion</a>) are enabled.
+(see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>) are enabled.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>progcomp_alias</code></span></dt>
+<dt><code class="code">progcomp_alias</code></dt>
<dd><p>If set, and programmable completion is enabled, Bash treats a command
name that doesn’t have any completions as a possible alias and attempts
alias expansion. If it has an alias, Bash attempts programmable
completion using the command word resulting from the expanded alias.
</p>
</dd>
-<dt><span><code>promptvars</code></span></dt>
+<dt><code class="code">promptvars</code></dt>
<dd><p>If set, prompt strings undergo
parameter expansion, command substitution, arithmetic
expansion, and quote removal after being expanded
-as described below (see <a href="#Controlling-the-Prompt">Controlling the Prompt</a>).
+as described below (see <a class="pxref" href="#Controlling-the-Prompt">Controlling the Prompt</a>).
This option is enabled by default.
</p>
</dd>
-<dt><span><code>restricted_shell</code></span></dt>
+<dt><code class="code">restricted_shell</code></dt>
<dd><p>The shell sets this option if it is started in restricted mode
-(see <a href="#The-Restricted-Shell">The Restricted Shell</a>).
+(see <a class="pxref" href="#The-Restricted-Shell">The Restricted Shell</a>).
The value may not be changed.
This is not reset when the startup files are executed, allowing
the startup files to discover whether or not a shell is restricted.
</p>
</dd>
-<dt><span><code>shift_verbose</code></span></dt>
-<dd><p>If this is set, the <code>shift</code>
+<dt><code class="code">shift_verbose</code></dt>
+<dd><p>If this is set, the <code class="code">shift</code>
builtin prints an error message when the shift count exceeds the
number of positional parameters.
</p>
</dd>
-<dt><span><code>sourcepath</code></span></dt>
-<dd><p>If set, the <code>.</code> (<code>source</code>) builtin uses the value of <code>PATH</code>
+<dt><code class="code">sourcepath</code></dt>
+<dd><p>If set, the <code class="code">.</code> (<code class="code">source</code>) builtin uses the value of <code class="env">PATH</code>
to find the directory containing the file supplied as an argument.
This option is enabled by default.
</p>
</dd>
-<dt><span><code>varredir_close</code></span></dt>
+<dt><code class="code">varredir_close</code></dt>
<dd><p>If set, the shell automatically closes file descriptors assigned using the
-<code>{varname}</code> redirection syntax (see <a href="#Redirections">Redirections</a>) instead of
+<code class="code">{varname}</code> redirection syntax (see <a class="pxref" href="#Redirections">Redirections</a>) instead of
leaving them open when the command completes.
</p>
</dd>
-<dt><span><code>xpg_echo</code></span></dt>
-<dd><p>If set, the <code>echo</code> builtin expands backslash-escape sequences
+<dt><code class="code">xpg_echo</code></dt>
+<dd><p>If set, the <code class="code">echo</code> builtin expands backslash-escape sequences
by default.
-If the <code>posix</code> shell option (see <a href="#The-Set-Builtin">The Set Builtin</a>) is also enabled,
-<code>echo</code> does not
+If the <code class="code">posix</code> shell option (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>) is also enabled,
+<code class="code">echo</code> does not
interpret any options.
</p>
</dd>
<hr>
</div>
</div>
-<div class="section" id="Special-Builtins">
-<div class="header">
+<div class="section-level-extent" id="Special-Builtins">
+<div class="nav-panel">
<p>
Previous: <a href="#Modifying-Shell-Behavior" accesskey="p" rel="prev">Modifying Shell Behavior</a>, Up: <a href="#Shell-Builtin-Commands" accesskey="u" rel="up">Shell Builtin Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Special-Builtins-1"></span><h3 class="section">4.4 Special Builtins</h3>
-<span id="index-special-builtin-1"></span>
+<h3 class="section" id="Special-Builtins-1"><span>4.4 Special Builtins<a class="copiable-link" href="#Special-Builtins-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-special-builtin-1"></a>
-<p>For historical reasons, the <small>POSIX</small> standard has classified
-several builtin commands as <em>special</em>.
-When Bash is executing in <small>POSIX</small> mode, the special builtins
+<p>For historical reasons, the <small class="sc">POSIX</small> standard has classified
+several builtin commands as <em class="emph">special</em>.
+When Bash is executing in <small class="sc">POSIX</small> mode, the special builtins
differ from other builtin commands in three respects:
</p>
-<ol>
+<ol class="enumerate">
<li> Special builtins are found before shell functions during command lookup.
</li><li> If a special builtin returns an error status, a non-interactive shell exits.
environment after the command completes.
</li></ol>
-<p>When Bash is not executing in <small>POSIX</small> mode, these builtins behave no
+<p>When Bash is not executing in <small class="sc">POSIX</small> mode, these builtins behave no
differently than the rest of the Bash builtin commands.
-The Bash <small>POSIX</small> mode is described in <a href="#Bash-POSIX-Mode">Bash and POSIX</a>.
+The Bash <small class="sc">POSIX</small> mode is described in <a class="ref" href="#Bash-POSIX-Mode">Bash and POSIX</a>.
</p>
-<p>These are the <small>POSIX</small> special builtins:
+<p>These are the <small class="sc">POSIX</small> special builtins:
</p><div class="example">
-<pre class="example">break : . source continue eval exec exit export readonly return set<!-- /@w -->
+<pre class="example-preformatted">break : . source continue eval exec exit export readonly return set<!-- /@w -->
shift times trap unset<!-- /@w -->
</pre></div>
<hr>
</div>
</div>
-<div class="chapter" id="Shell-Variables">
-<div class="header">
+<div class="chapter-level-extent" id="Shell-Variables">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-Features" accesskey="n" rel="next">Bash Features</a>, Previous: <a href="#Shell-Builtin-Commands" accesskey="p" rel="prev">Shell Builtin Commands</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Variables-1"></span><h2 class="chapter">5 Shell Variables</h2>
+<h2 class="chapter" id="Shell-Variables-1"><span>5 Shell Variables<a class="copiable-link" href="#Shell-Variables-1"> ¶</a></span></h2>
<p>This chapter describes the shell variables that Bash uses.
Bash automatically assigns default values to a number of variables.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Bourne-Shell-Variables" accesskey="1">Bourne Shell Variables</a></li>
<li><a href="#Bash-Variables" accesskey="2">Bash Variables</a></li>
</ul>
<hr>
-<div class="section" id="Bourne-Shell-Variables">
-<div class="header">
+<div class="section-level-extent" id="Bourne-Shell-Variables">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-Variables" accesskey="n" rel="next">Bash Variables</a>, Up: <a href="#Shell-Variables" accesskey="u" rel="up">Shell Variables</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bourne-Shell-Variables-1"></span><h3 class="section">5.1 Bourne Shell Variables</h3>
+<h3 class="section" id="Bourne-Shell-Variables-1"><span>5.1 Bourne Shell Variables<a class="copiable-link" href="#Bourne-Shell-Variables-1"> ¶</a></span></h3>
<p>Bash uses certain shell variables in the same way as the Bourne shell.
In some cases, Bash assigns a default value to the variable.
</p>
-<dl compact="compact">
-<dt id='index-CDPATH'><span><code>CDPATH</code><a href='#index-CDPATH' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="vtable">
+<dt><a id="index-CDPATH"></a><span><code class="code">CDPATH</code><a class="copiable-link" href="#index-CDPATH"> ¶</a></span></dt>
<dd><p>A colon-separated list of directories used as a search path for
-the <code>cd</code> builtin command.
+the <code class="code">cd</code> builtin command.
</p>
</dd>
-<dt id='index-HOME'><span><code>HOME</code><a href='#index-HOME' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The current user’s home directory; the default for the <code>cd</code> builtin
+<dt><a id="index-HOME"></a><span><code class="code">HOME</code><a class="copiable-link" href="#index-HOME"> ¶</a></span></dt>
+<dd><p>The current user’s home directory; the default for the <code class="code">cd</code> builtin
command.
The value of this variable is also used by tilde expansion
-(see <a href="#Tilde-Expansion">Tilde Expansion</a>).
+(see <a class="pxref" href="#Tilde-Expansion">Tilde Expansion</a>).
</p>
</dd>
-<dt id='index-IFS'><span><code>IFS</code><a href='#index-IFS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-IFS"></a><span><code class="code">IFS</code><a class="copiable-link" href="#index-IFS"> ¶</a></span></dt>
<dd><p>A list of characters that separate fields; used when the shell splits
words as part of expansion.
</p>
</dd>
-<dt id='index-MAIL'><span><code>MAIL</code><a href='#index-MAIL' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-MAIL"></a><span><code class="code">MAIL</code><a class="copiable-link" href="#index-MAIL"> ¶</a></span></dt>
<dd><p>If this parameter is set to a filename or directory name
-and the <code>MAILPATH</code> variable
+and the <code class="env">MAILPATH</code> variable
is not set, Bash informs the user of the arrival of mail in
the specified file or Maildir-format directory.
</p>
</dd>
-<dt id='index-MAILPATH'><span><code>MAILPATH</code><a href='#index-MAILPATH' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-MAILPATH"></a><span><code class="code">MAILPATH</code><a class="copiable-link" href="#index-MAILPATH"> ¶</a></span></dt>
<dd><p>A colon-separated list of filenames which the shell periodically checks
for new mail.
Each list entry can specify the message that is printed when new mail
arrives in the mail file by separating the filename from the message with
-a ‘<samp>?</samp>’.
-When used in the text of the message, <code>$_</code> expands to the name of
+a ‘<samp class="samp">?</samp>’.
+When used in the text of the message, <code class="code">$_</code> expands to the name of
the current mail file.
</p>
</dd>
-<dt id='index-OPTARG'><span><code>OPTARG</code><a href='#index-OPTARG' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The value of the last option argument processed by the <code>getopts</code> builtin.
+<dt><a id="index-OPTARG"></a><span><code class="code">OPTARG</code><a class="copiable-link" href="#index-OPTARG"> ¶</a></span></dt>
+<dd><p>The value of the last option argument processed by the <code class="code">getopts</code> builtin.
</p>
</dd>
-<dt id='index-OPTIND'><span><code>OPTIND</code><a href='#index-OPTIND' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The index of the last option argument processed by the <code>getopts</code> builtin.
+<dt><a id="index-OPTIND"></a><span><code class="code">OPTIND</code><a class="copiable-link" href="#index-OPTIND"> ¶</a></span></dt>
+<dd><p>The index of the last option argument processed by the <code class="code">getopts</code> builtin.
</p>
</dd>
-<dt id='index-PATH'><span><code>PATH</code><a href='#index-PATH' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-PATH"></a><span><code class="code">PATH</code><a class="copiable-link" href="#index-PATH"> ¶</a></span></dt>
<dd><p>A colon-separated list of directories in which the shell looks for
commands.
-A zero-length (null) directory name in the value of <code>PATH</code> indicates the
+A zero-length (null) directory name in the value of <code class="code">PATH</code> indicates the
current directory.
A null directory name may appear as two adjacent colons, or as an initial
or trailing colon.
</p>
</dd>
-<dt id='index-PS1'><span><code>PS1</code><a href='#index-PS1' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The primary prompt string. The default value is ‘<samp>\s-\v\$ </samp>’.
-See <a href="#Controlling-the-Prompt">Controlling the Prompt</a>, for the complete list of escape
-sequences that are expanded before <code>PS1</code> is displayed.
+<dt><a id="index-PS1"></a><span><code class="code">PS1</code><a class="copiable-link" href="#index-PS1"> ¶</a></span></dt>
+<dd><p>The primary prompt string. The default value is ‘<samp class="samp">\s-\v\$ </samp>’.
+See <a class="xref" href="#Controlling-the-Prompt">Controlling the Prompt</a>, for the complete list of escape
+sequences that are expanded before <code class="env">PS1</code> is displayed.
</p>
</dd>
-<dt id='index-PS2'><span><code>PS2</code><a href='#index-PS2' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The secondary prompt string. The default value is ‘<samp>> </samp>’.
-<code>PS2</code> is expanded in the same way as <code>PS1</code> before being
+<dt><a id="index-PS2"></a><span><code class="code">PS2</code><a class="copiable-link" href="#index-PS2"> ¶</a></span></dt>
+<dd><p>The secondary prompt string. The default value is ‘<samp class="samp">> </samp>’.
+<code class="env">PS2</code> is expanded in the same way as <code class="env">PS1</code> before being
displayed.
</p>
</dd>
<hr>
</div>
-<div class="section" id="Bash-Variables">
-<div class="header">
+<div class="section-level-extent" id="Bash-Variables">
+<div class="nav-panel">
<p>
Previous: <a href="#Bourne-Shell-Variables" accesskey="p" rel="prev">Bourne Shell Variables</a>, Up: <a href="#Shell-Variables" accesskey="u" rel="up">Shell Variables</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-Variables-1"></span><h3 class="section">5.2 Bash Variables</h3>
+<h3 class="section" id="Bash-Variables-1"><span>5.2 Bash Variables<a class="copiable-link" href="#Bash-Variables-1"> ¶</a></span></h3>
<p>These variables are set or used by Bash, but other shells
do not normally treat them specially.
</p>
<p>A few variables used by Bash are described in different chapters:
variables for controlling the job control facilities
-(see <a href="#Job-Control-Variables">Job Control Variables</a>).
+(see <a class="pxref" href="#Job-Control-Variables">Job Control Variables</a>).
</p>
-<dl compact="compact">
-<dt id='index-_005f'><span><code>_</code><a href='#index-_005f' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-_0024_005f"></span>
+<dl class="vtable">
+<dt><a id="index-_005f"></a><span><code class="code">_</code><a class="copiable-link" href="#index-_005f"> ¶</a></span></dt>
+<dd><a class="index-entry-id" id="index-_0024_005f"></a>
<p>($_, an underscore.)
At shell startup, set to the pathname used to invoke the
shell or shell script being executed as passed in the environment
When checking mail, this parameter holds the name of the mail file.
</p>
</dd>
-<dt id='index-BASH'><span><code>BASH</code><a href='#index-BASH' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH"></a><span><code class="code">BASH</code><a class="copiable-link" href="#index-BASH"> ¶</a></span></dt>
<dd><p>The full pathname used to execute the current instance of Bash.
</p>
</dd>
-<dt id='index-BASHOPTS'><span><code>BASHOPTS</code><a href='#index-BASHOPTS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASHOPTS"></a><span><code class="code">BASHOPTS</code><a class="copiable-link" href="#index-BASHOPTS"> ¶</a></span></dt>
<dd><p>A colon-separated list of enabled shell options. Each word in
-the list is a valid argument for the <samp>-s</samp> option to the
-<code>shopt</code> builtin command (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
-The options appearing in <code>BASHOPTS</code> are those reported
-as ‘<samp>on</samp>’ by ‘<samp>shopt</samp>’.
+the list is a valid argument for the <samp class="option">-s</samp> option to the
+<code class="code">shopt</code> builtin command (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+The options appearing in <code class="env">BASHOPTS</code> are those reported
+as ‘<samp class="samp">on</samp>’ by ‘<samp class="samp">shopt</samp>’.
If this variable is in the environment when Bash
starts up, each shell option in the list will be enabled before
reading any startup files. This variable is readonly.
</p>
</dd>
-<dt id='index-BASHPID'><span><code>BASHPID</code><a href='#index-BASHPID' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASHPID"></a><span><code class="code">BASHPID</code><a class="copiable-link" href="#index-BASHPID"> ¶</a></span></dt>
<dd><p>Expands to the process ID of the current Bash process.
-This differs from <code>$$</code> under certain circumstances, such as subshells
+This differs from <code class="code">$$</code> under certain circumstances, such as subshells
that do not require Bash to be re-initialized.
-Assignments to <code>BASHPID</code> have no effect.
-If <code>BASHPID</code>
+Assignments to <code class="env">BASHPID</code> have no effect.
+If <code class="env">BASHPID</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fALIASES'><span><code>BASH_ALIASES</code><a href='#index-BASH_005fALIASES' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fALIASES"></a><span><code class="code">BASH_ALIASES</code><a class="copiable-link" href="#index-BASH_005fALIASES"> ¶</a></span></dt>
<dd><p>An associative array variable whose members correspond to the internal
-list of aliases as maintained by the <code>alias</code> builtin.
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+list of aliases as maintained by the <code class="code">alias</code> builtin.
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
Elements added to this array appear in the alias list; however,
unsetting array elements currently does not cause aliases to be removed
from the alias list.
-If <code>BASH_ALIASES</code>
+If <code class="env">BASH_ALIASES</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fARGC'><span><code>BASH_ARGC</code><a href='#index-BASH_005fARGC' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fARGC"></a><span><code class="code">BASH_ARGC</code><a class="copiable-link" href="#index-BASH_005fARGC"> ¶</a></span></dt>
<dd><p>An array variable whose values are the number of parameters in each
frame of the current Bash execution call stack. The number of
parameters to the current subroutine (shell function or script executed
-with <code>.</code> or <code>source</code>) is at the top of the stack. When a
+with <code class="code">.</code> or <code class="code">source</code>) is at the top of the stack. When a
subroutine is executed, the number of parameters passed is pushed onto
-<code>BASH_ARGC</code>.
-The shell sets <code>BASH_ARGC</code> only when in extended debugging mode
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>
-for a description of the <code>extdebug</code> option to the <code>shopt</code>
+<code class="code">BASH_ARGC</code>.
+The shell sets <code class="code">BASH_ARGC</code> only when in extended debugging mode
+(see <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>
+for a description of the <code class="code">extdebug</code> option to the <code class="code">shopt</code>
builtin).
-Setting <code>extdebug</code> after the shell has started to execute a script,
-or referencing this variable when <code>extdebug</code> is not set,
+Setting <code class="code">extdebug</code> after the shell has started to execute a script,
+or referencing this variable when <code class="code">extdebug</code> is not set,
may result in inconsistent values.
-Assignments to <code>BASH_ARGC</code> have no effect, and it may not be unset.
+Assignments to <code class="env">BASH_ARGC</code> have no effect, and it may not be unset.
</p>
</dd>
-<dt id='index-BASH_005fARGV'><span><code>BASH_ARGV</code><a href='#index-BASH_005fARGV' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fARGV"></a><span><code class="code">BASH_ARGV</code><a class="copiable-link" href="#index-BASH_005fARGV"> ¶</a></span></dt>
<dd><p>An array variable containing all of the parameters in the current Bash
execution call stack. The final parameter of the last subroutine call
is at the top of the stack; the first parameter of the initial call is
at the bottom. When a subroutine is executed, the parameters supplied
-are pushed onto <code>BASH_ARGV</code>.
-The shell sets <code>BASH_ARGV</code> only when in extended debugging mode
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>
-for a description of the <code>extdebug</code> option to the <code>shopt</code>
+are pushed onto <code class="code">BASH_ARGV</code>.
+The shell sets <code class="code">BASH_ARGV</code> only when in extended debugging mode
+(see <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>
+for a description of the <code class="code">extdebug</code> option to the <code class="code">shopt</code>
builtin).
-Setting <code>extdebug</code> after the shell has started to execute a script,
-or referencing this variable when <code>extdebug</code> is not set,
+Setting <code class="code">extdebug</code> after the shell has started to execute a script,
+or referencing this variable when <code class="code">extdebug</code> is not set,
may result in inconsistent values.
-Assignments to <code>BASH_ARGV</code> have no effect, and it may not be unset.
+Assignments to <code class="env">BASH_ARGV</code> have no effect, and it may not be unset.
</p>
</dd>
-<dt id='index-BASH_005fARGV0'><span><code>BASH_ARGV0</code><a href='#index-BASH_005fARGV0' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fARGV0"></a><span><code class="code">BASH_ARGV0</code><a class="copiable-link" href="#index-BASH_005fARGV0"> ¶</a></span></dt>
<dd><p>When referenced, this variable expands to the name of the shell or shell
-script (identical to <code>$0</code>; See <a href="#Special-Parameters">Special Parameters</a>,
+script (identical to <code class="code">$0</code>; See <a class="xref" href="#Special-Parameters">Special Parameters</a>,
for the description of special parameter 0).
-Assignment to <code>BASH_ARGV0</code>
-causes the value assigned to also be assigned to <code>$0</code>.
-If <code>BASH_ARGV0</code>
+Assignment to <code class="code">BASH_ARGV0</code>
+causes the value assigned to also be assigned to <code class="code">$0</code>.
+If <code class="env">BASH_ARGV0</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fCMDS'><span><code>BASH_CMDS</code><a href='#index-BASH_005fCMDS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fCMDS"></a><span><code class="code">BASH_CMDS</code><a class="copiable-link" href="#index-BASH_005fCMDS"> ¶</a></span></dt>
<dd><p>An associative array variable whose members correspond to the internal
-hash table of commands as maintained by the <code>hash</code> builtin
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+hash table of commands as maintained by the <code class="code">hash</code> builtin
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
Elements added to this array appear in the hash table; however,
unsetting array elements currently does not cause command names to be removed
from the hash table.
-If <code>BASH_CMDS</code>
+If <code class="env">BASH_CMDS</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fCOMMAND'><span><code>BASH_COMMAND</code><a href='#index-BASH_005fCOMMAND' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fCOMMAND"></a><span><code class="code">BASH_COMMAND</code><a class="copiable-link" href="#index-BASH_005fCOMMAND"> ¶</a></span></dt>
<dd><p>The command currently being executed or about to be executed, unless the
shell is executing a command as the result of a trap,
in which case it is the command executing at the time of the trap.
-If <code>BASH_COMMAND</code>
+If <code class="env">BASH_COMMAND</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fCOMPAT'><span><code>BASH_COMPAT</code><a href='#index-BASH_005fCOMPAT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fCOMPAT"></a><span><code class="code">BASH_COMPAT</code><a class="copiable-link" href="#index-BASH_005fCOMPAT"> ¶</a></span></dt>
<dd><p>The value is used to set the shell’s compatibility level.
-See <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>, for a description of the various
+See <a class="xref" href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>, for a description of the various
compatibility levels and their effects.
The value may be a decimal number (e.g., 4.2) or an integer (e.g., 42)
corresponding to the desired compatibility level.
-If <code>BASH_COMPAT</code> is unset or set to the empty string, the compatibility
+If <code class="env">BASH_COMPAT</code> is unset or set to the empty string, the compatibility
level is set to the default for the current version.
-If <code>BASH_COMPAT</code> is set to a value that is not one of the valid
+If <code class="env">BASH_COMPAT</code> is set to a value that is not one of the valid
compatibility levels, the shell prints an error message and sets the
compatibility level to the default for the current version.
-The valid values correspond to the compatibility levels
-described below (see <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>).
+A subset of the valid values correspond to the compatibility levels
+described below (see <a class="pxref" href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>).
For example, 4.2 and 42 are valid values that correspond
-to the <code>compat42</code> <code>shopt</code> option
+to the <code class="code">compat42</code> <code class="code">shopt</code> option
and set the compatibility level to 42.
The current version is also a valid value.
</p>
</dd>
-<dt id='index-BASH_005fENV'><span><code>BASH_ENV</code><a href='#index-BASH_005fENV' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fENV"></a><span><code class="code">BASH_ENV</code><a class="copiable-link" href="#index-BASH_005fENV"> ¶</a></span></dt>
<dd><p>If this variable is set when Bash is invoked to execute a shell
script, its value is expanded and used as the name of a startup file
-to read before executing the script. See <a href="#Bash-Startup-Files">Bash Startup Files</a>.
+to read before executing the script. See <a class="xref" href="#Bash-Startup-Files">Bash Startup Files</a>.
</p>
</dd>
-<dt id='index-BASH_005fEXECUTION_005fSTRING'><span><code>BASH_EXECUTION_STRING</code><a href='#index-BASH_005fEXECUTION_005fSTRING' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The command argument to the <samp>-c</samp> invocation option.
+<dt><a id="index-BASH_005fEXECUTION_005fSTRING"></a><span><code class="code">BASH_EXECUTION_STRING</code><a class="copiable-link" href="#index-BASH_005fEXECUTION_005fSTRING"> ¶</a></span></dt>
+<dd><p>The command argument to the <samp class="option">-c</samp> invocation option.
</p>
</dd>
-<dt id='index-BASH_005fLINENO'><span><code>BASH_LINENO</code><a href='#index-BASH_005fLINENO' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fLINENO"></a><span><code class="code">BASH_LINENO</code><a class="copiable-link" href="#index-BASH_005fLINENO"> ¶</a></span></dt>
<dd><p>An array variable whose members are the line numbers in source files
-where each corresponding member of <code>FUNCNAME</code> was invoked.
-<code>${BASH_LINENO[$i]}</code> is the line number in the source file
-(<code>${BASH_SOURCE[$i+1]}</code>) where
-<code>${FUNCNAME[$i]}</code> was called (or <code>${BASH_LINENO[$i-1]}</code> if
+where each corresponding member of <code class="env">FUNCNAME</code> was invoked.
+<code class="code">${BASH_LINENO[$i]}</code> is the line number in the source file
+(<code class="code">${BASH_SOURCE[$i+1]}</code>) where
+<code class="code">${FUNCNAME[$i]}</code> was called (or <code class="code">${BASH_LINENO[$i-1]}</code> if
referenced within another shell function).
-Use <code>LINENO</code> to obtain the current line number.
-Assignments to <code>BASH_LINENO</code> have no effect, and it may not be unset.
+Use <code class="code">LINENO</code> to obtain the current line number.
+Assignments to <code class="env">BASH_LINENO</code> have no effect, and it may not be unset.
</p>
</dd>
-<dt id='index-BASH_005fLOADABLES_005fPATH'><span><code>BASH_LOADABLES_PATH</code><a href='#index-BASH_005fLOADABLES_005fPATH' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fLOADABLES_005fPATH"></a><span><code class="code">BASH_LOADABLES_PATH</code><a class="copiable-link" href="#index-BASH_005fLOADABLES_005fPATH"> ¶</a></span></dt>
<dd><p>A colon-separated list of directories in which the shell looks for
dynamically loadable builtins specified by the
-<code>enable</code> command.
+<code class="code">enable</code> command.
</p>
</dd>
-<dt id='index-BASH_005fMONOSECONDS'><span><code>BASH_MONOSECONDS</code><a href='#index-BASH_005fMONOSECONDS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fMONOSECONDS"></a><span><code class="code">BASH_MONOSECONDS</code><a class="copiable-link" href="#index-BASH_005fMONOSECONDS"> ¶</a></span></dt>
<dd><p>Each time this variable is referenced, it expands to the value returned
by the system’s monotonic clock, if one is available.
-If there is no monotonic clock, this is equivalent to <code>EPOCHSECONDS</code>.
-If <code>BASH_MONOSECONDS</code>
+If there is no monotonic clock, this is equivalent to <code class="env">EPOCHSECONDS</code>.
+If <code class="env">BASH_MONOSECONDS</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fREMATCH'><span><code>BASH_REMATCH</code><a href='#index-BASH_005fREMATCH' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>An array variable whose members are assigned by the ‘<samp>=~</samp>’ binary
-operator to the <code>[[</code> conditional command
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+<dt><a id="index-BASH_005fREMATCH"></a><span><code class="code">BASH_REMATCH</code><a class="copiable-link" href="#index-BASH_005fREMATCH"> ¶</a></span></dt>
+<dd><p>An array variable whose members are assigned by the ‘<samp class="samp">=~</samp>’ binary
+operator to the <code class="code">[[</code> conditional command
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
The element with index 0 is the portion of the string
matching the entire regular expression.
-The element with index <var>n</var> is the portion of the
-string matching the <var>n</var>th parenthesized subexpression.
+The element with index <var class="var">n</var> is the portion of the
+string matching the <var class="var">n</var>th parenthesized subexpression.
</p>
</dd>
-<dt id='index-BASH_005fSOURCE'><span><code>BASH_SOURCE</code><a href='#index-BASH_005fSOURCE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fSOURCE"></a><span><code class="code">BASH_SOURCE</code><a class="copiable-link" href="#index-BASH_005fSOURCE"> ¶</a></span></dt>
<dd><p>An array variable whose members are the source filenames where the
-corresponding shell function names in the <code>FUNCNAME</code> array
+corresponding shell function names in the <code class="code">FUNCNAME</code> array
variable are defined.
-The shell function <code>${FUNCNAME[$i]}</code> is defined in the file
-<code>${BASH_SOURCE[$i]}</code> and called from <code>${BASH_SOURCE[$i+1]}</code>
-Assignments to <code>BASH_SOURCE</code> have no effect, and it may not be unset.
+The shell function <code class="code">${FUNCNAME[$i]}</code> is defined in the file
+<code class="code">${BASH_SOURCE[$i]}</code> and called from <code class="code">${BASH_SOURCE[$i+1]}</code>
+Assignments to <code class="env">BASH_SOURCE</code> have no effect, and it may not be unset.
</p>
</dd>
-<dt id='index-BASH_005fSUBSHELL'><span><code>BASH_SUBSHELL</code><a href='#index-BASH_005fSUBSHELL' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fSUBSHELL"></a><span><code class="code">BASH_SUBSHELL</code><a class="copiable-link" href="#index-BASH_005fSUBSHELL"> ¶</a></span></dt>
<dd><p>Incremented by one within each subshell or subshell environment when
the shell begins executing in that environment.
The initial value is 0.
-If <code>BASH_SUBSHELL</code>
+If <code class="env">BASH_SUBSHELL</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-BASH_005fTRAPSIG'><span><code>BASH_TRAPSIG</code><a href='#index-BASH_005fTRAPSIG' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fTRAPSIG"></a><span><code class="code">BASH_TRAPSIG</code><a class="copiable-link" href="#index-BASH_005fTRAPSIG"> ¶</a></span></dt>
<dd><p>Set to the signal number corresponding to the trap action being executed
during its execution.
-See the description of <code>trap</code>
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
+See the description of <code class="code">trap</code>
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
for information about signal numbers and trap execution.
</p>
</dd>
-<dt id='index-BASH_005fVERSINFO'><span><code>BASH_VERSINFO</code><a href='#index-BASH_005fVERSINFO' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A readonly array variable (see <a href="#Arrays">Arrays</a>)
+<dt><a id="index-BASH_005fVERSINFO"></a><span><code class="code">BASH_VERSINFO</code><a class="copiable-link" href="#index-BASH_005fVERSINFO"> ¶</a></span></dt>
+<dd><p>A readonly array variable (see <a class="pxref" href="#Arrays">Arrays</a>)
whose members hold version information for this instance of Bash.
The values assigned to the array members are as follows:
</p>
-<dl compact="compact">
-<dt><span><code>BASH_VERSINFO[0]</code></span></dt>
-<dd><p>The major version number (the <em>release</em>).
+<dl class="table">
+<dt><code class="code">BASH_VERSINFO[0]</code></dt>
+<dd><p>The major version number (the <em class="dfn">release</em>).
</p>
</dd>
-<dt><span><code>BASH_VERSINFO[1]</code></span></dt>
-<dd><p>The minor version number (the <em>version</em>).
+<dt><code class="code">BASH_VERSINFO[1]</code></dt>
+<dd><p>The minor version number (the <em class="dfn">version</em>).
</p>
</dd>
-<dt><span><code>BASH_VERSINFO[2]</code></span></dt>
+<dt><code class="code">BASH_VERSINFO[2]</code></dt>
<dd><p>The patch level.
</p>
</dd>
-<dt><span><code>BASH_VERSINFO[3]</code></span></dt>
+<dt><code class="code">BASH_VERSINFO[3]</code></dt>
<dd><p>The build version.
</p>
</dd>
-<dt><span><code>BASH_VERSINFO[4]</code></span></dt>
-<dd><p>The release status (e.g., <code>beta1</code>).
+<dt><code class="code">BASH_VERSINFO[4]</code></dt>
+<dd><p>The release status (e.g., <code class="code">beta</code>).
</p>
</dd>
-<dt><span><code>BASH_VERSINFO[5]</code></span></dt>
-<dd><p>The value of <code>MACHTYPE</code>.
+<dt><code class="code">BASH_VERSINFO[5]</code></dt>
+<dd><p>The value of <code class="env">MACHTYPE</code>.
</p></dd>
</dl>
</dd>
-<dt id='index-BASH_005fVERSION'><span><code>BASH_VERSION</code><a href='#index-BASH_005fVERSION' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fVERSION"></a><span><code class="code">BASH_VERSION</code><a class="copiable-link" href="#index-BASH_005fVERSION"> ¶</a></span></dt>
<dd><p>The version number of the current instance of Bash.
</p>
</dd>
-<dt id='index-BASH_005fXTRACEFD'><span><code>BASH_XTRACEFD</code><a href='#index-BASH_005fXTRACEFD' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-BASH_005fXTRACEFD"></a><span><code class="code">BASH_XTRACEFD</code><a class="copiable-link" href="#index-BASH_005fXTRACEFD"> ¶</a></span></dt>
<dd><p>If set to an integer corresponding to a valid file descriptor, Bash
-will write the trace output generated when ‘<samp>set -x</samp>’
+will write the trace output generated when ‘<samp class="samp">set -x</samp>’
is enabled to that file descriptor.
This allows tracing output to be separated from diagnostic and error
messages.
-The file descriptor is closed when <code>BASH_XTRACEFD</code> is unset or assigned
+The file descriptor is closed when <code class="code">BASH_XTRACEFD</code> is unset or assigned
a new value.
-Unsetting <code>BASH_XTRACEFD</code> or assigning it the empty string causes the
+Unsetting <code class="code">BASH_XTRACEFD</code> or assigning it the empty string causes the
trace output to be sent to the standard error.
-Note that setting <code>BASH_XTRACEFD</code> to 2 (the standard error file
+Note that setting <code class="code">BASH_XTRACEFD</code> to 2 (the standard error file
descriptor) and then unsetting it will result in the standard error
being closed.
</p>
</dd>
-<dt id='index-CHILD_005fMAX'><span><code>CHILD_MAX</code><a href='#index-CHILD_005fMAX' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-CHILD_005fMAX"></a><span><code class="code">CHILD_MAX</code><a class="copiable-link" href="#index-CHILD_005fMAX"> ¶</a></span></dt>
<dd><p>Set the number of exited child status values for the shell to remember.
-Bash will not allow this value to be decreased below a <small>POSIX</small>-mandated
+Bash will not allow this value to be decreased below a <small class="sc">POSIX</small>-mandated
minimum, and there is a maximum value (currently 8192) that this may
not exceed.
The minimum value is system-dependent.
</p>
</dd>
-<dt id='index-COLUMNS'><span><code>COLUMNS</code><a href='#index-COLUMNS' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Used by the <code>select</code> command to determine the terminal width
+<dt><a id="index-COLUMNS"></a><span><code class="code">COLUMNS</code><a class="copiable-link" href="#index-COLUMNS"> ¶</a></span></dt>
+<dd><p>Used by the <code class="code">select</code> command to determine the terminal width
when printing selection lists.
-Automatically set if the <code>checkwinsize</code> option is enabled
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), or in an interactive shell upon receipt of a
-<code>SIGWINCH</code>.
+Automatically set if the <code class="code">checkwinsize</code> option is enabled
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>), or in an interactive shell upon receipt of a
+<code class="code">SIGWINCH</code>.
</p>
</dd>
-<dt id='index-COMP_005fCWORD'><span><code>COMP_CWORD</code><a href='#index-COMP_005fCWORD' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>An index into <code>${COMP_WORDS}</code> of the word containing the current
+<dt><a id="index-COMP_005fCWORD"></a><span><code class="code">COMP_CWORD</code><a class="copiable-link" href="#index-COMP_005fCWORD"> ¶</a></span></dt>
+<dd><p>An index into <code class="env">${COMP_WORDS}</code> of the word containing the current
cursor position.
This variable is available only in shell functions invoked by the
-programmable completion facilities (see <a href="#Programmable-Completion">Programmable Completion</a>).
+programmable completion facilities (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
</p>
</dd>
-<dt id='index-COMP_005fLINE'><span><code>COMP_LINE</code><a href='#index-COMP_005fLINE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMP_005fLINE"></a><span><code class="code">COMP_LINE</code><a class="copiable-link" href="#index-COMP_005fLINE"> ¶</a></span></dt>
<dd><p>The current command line.
This variable is available only in shell functions and external
commands invoked by the
-programmable completion facilities (see <a href="#Programmable-Completion">Programmable Completion</a>).
+programmable completion facilities (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
</p>
</dd>
-<dt id='index-COMP_005fPOINT'><span><code>COMP_POINT</code><a href='#index-COMP_005fPOINT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMP_005fPOINT"></a><span><code class="code">COMP_POINT</code><a class="copiable-link" href="#index-COMP_005fPOINT"> ¶</a></span></dt>
<dd><p>The index of the current cursor position relative to the beginning of
the current command.
If the current cursor position is at the end of the current command,
-the value of this variable is equal to <code>${#COMP_LINE}</code>.
+the value of this variable is equal to <code class="code">${#COMP_LINE}</code>.
This variable is available only in shell functions and external
commands invoked by the
-programmable completion facilities (see <a href="#Programmable-Completion">Programmable Completion</a>).
+programmable completion facilities (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
</p>
</dd>
-<dt id='index-COMP_005fTYPE'><span><code>COMP_TYPE</code><a href='#index-COMP_005fTYPE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMP_005fTYPE"></a><span><code class="code">COMP_TYPE</code><a class="copiable-link" href="#index-COMP_005fTYPE"> ¶</a></span></dt>
<dd><p>Set to an integer value corresponding to the type of completion attempted
that caused a completion function to be called:
-<tt class="key">TAB</tt>, for normal completion,
-‘<samp>?</samp>’, for listing completions after successive tabs,
-‘<samp>!</samp>’, for listing alternatives on partial word completion,
-‘<samp>@</samp>’, to list completions if the word is not unmodified,
+<kbd class="key">TAB</kbd>, for normal completion,
+‘<samp class="samp">?</samp>’, for listing completions after successive tabs,
+‘<samp class="samp">!</samp>’, for listing alternatives on partial word completion,
+‘<samp class="samp">@</samp>’, to list completions if the word is not unmodified,
or
-‘<samp>%</samp>’, for menu completion.
+‘<samp class="samp">%</samp>’, for menu completion.
This variable is available only in shell functions and external
commands invoked by the
-programmable completion facilities (see <a href="#Programmable-Completion">Programmable Completion</a>).
+programmable completion facilities (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
</p>
</dd>
-<dt id='index-COMP_005fKEY'><span><code>COMP_KEY</code><a href='#index-COMP_005fKEY' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMP_005fKEY"></a><span><code class="code">COMP_KEY</code><a class="copiable-link" href="#index-COMP_005fKEY"> ¶</a></span></dt>
<dd><p>The key (or final key of a key sequence) used to invoke the current
completion function.
</p>
</dd>
-<dt id='index-COMP_005fWORDBREAKS'><span><code>COMP_WORDBREAKS</code><a href='#index-COMP_005fWORDBREAKS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMP_005fWORDBREAKS"></a><span><code class="code">COMP_WORDBREAKS</code><a class="copiable-link" href="#index-COMP_005fWORDBREAKS"> ¶</a></span></dt>
<dd><p>The set of characters that the Readline library treats as word
separators when performing word completion.
-If <code>COMP_WORDBREAKS</code>
+If <code class="env">COMP_WORDBREAKS</code>
is unset, it loses its special properties,
even if it is subsequently reset.
</p>
</dd>
-<dt id='index-COMP_005fWORDS'><span><code>COMP_WORDS</code><a href='#index-COMP_005fWORDS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMP_005fWORDS"></a><span><code class="code">COMP_WORDS</code><a class="copiable-link" href="#index-COMP_005fWORDS"> ¶</a></span></dt>
<dd><p>An array variable consisting of the individual
words in the current command line.
The line is split into words as Readline would split it, using
-<code>COMP_WORDBREAKS</code> as described above.
+<code class="code">COMP_WORDBREAKS</code> as described above.
This variable is available only in shell functions invoked by the
-programmable completion facilities (see <a href="#Programmable-Completion">Programmable Completion</a>).
+programmable completion facilities (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
</p>
</dd>
-<dt id='index-COMPREPLY'><span><code>COMPREPLY</code><a href='#index-COMPREPLY' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COMPREPLY"></a><span><code class="code">COMPREPLY</code><a class="copiable-link" href="#index-COMPREPLY"> ¶</a></span></dt>
<dd><p>An array variable from which Bash reads the possible completions
generated by a shell function invoked by the programmable completion
-facility (see <a href="#Programmable-Completion">Programmable Completion</a>).
+facility (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
Each array element contains one possible completion.
</p>
</dd>
-<dt id='index-COPROC'><span><code>COPROC</code><a href='#index-COPROC' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-COPROC"></a><span><code class="code">COPROC</code><a class="copiable-link" href="#index-COPROC"> ¶</a></span></dt>
<dd><p>An array variable created to hold the file descriptors
-for output from and input to an unnamed coprocess (see <a href="#Coprocesses">Coprocesses</a>).
+for output from and input to an unnamed coprocess (see <a class="pxref" href="#Coprocesses">Coprocesses</a>).
</p>
</dd>
-<dt id='index-DIRSTACK'><span><code>DIRSTACK</code><a href='#index-DIRSTACK' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-DIRSTACK"></a><span><code class="code">DIRSTACK</code><a class="copiable-link" href="#index-DIRSTACK"> ¶</a></span></dt>
<dd><p>An array variable containing the current contents of the directory stack.
Directories appear in the stack in the order they are displayed by the
-<code>dirs</code> builtin.
+<code class="code">dirs</code> builtin.
Assigning to members of this array variable may be used to modify
-directories already in the stack, but the <code>pushd</code> and <code>popd</code>
+directories already in the stack, but the <code class="code">pushd</code> and <code class="code">popd</code>
builtins must be used to add and remove directories.
Assignment to this variable will not change the current directory.
-If <code>DIRSTACK</code>
+If <code class="env">DIRSTACK</code>
is unset, it loses its special properties, even if
it is subsequently reset.
</p>
</dd>
-<dt id='index-EMACS'><span><code>EMACS</code><a href='#index-EMACS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-EMACS"></a><span><code class="code">EMACS</code><a class="copiable-link" href="#index-EMACS"> ¶</a></span></dt>
<dd><p>If Bash finds this variable in the environment when the shell
-starts with value ‘<samp>t</samp>’, it assumes that the shell is running in an
+starts with value ‘<samp class="samp">t</samp>’, it assumes that the shell is running in an
Emacs shell buffer and disables line editing.
</p>
</dd>
-<dt id='index-ENV'><span><code>ENV</code><a href='#index-ENV' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Expanded and executed similarly to <code>BASH_ENV</code>
-(see <a href="#Bash-Startup-Files">Bash Startup Files</a>)
+<dt><a id="index-ENV"></a><span><code class="code">ENV</code><a class="copiable-link" href="#index-ENV"> ¶</a></span></dt>
+<dd><p>Expanded and executed similarly to <code class="code">BASH_ENV</code>
+(see <a class="pxref" href="#Bash-Startup-Files">Bash Startup Files</a>)
when an interactive shell is invoked in
-<small>POSIX</small> Mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>).
+<small class="sc">POSIX</small> Mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>).
</p>
</dd>
-<dt id='index-EPOCHREALTIME'><span><code>EPOCHREALTIME</code><a href='#index-EPOCHREALTIME' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-EPOCHREALTIME"></a><span><code class="code">EPOCHREALTIME</code><a class="copiable-link" href="#index-EPOCHREALTIME"> ¶</a></span></dt>
<dd><p>Each time this parameter is referenced, it expands to the number of seconds
since the Unix Epoch as a floating point value with micro-second granularity
-(see the documentation for the C library function <code>time</code> for the
+(see the documentation for the C library function <code class="code">time</code> for the
definition of Epoch).
-Assignments to <code>EPOCHREALTIME</code> are ignored.
-If <code>EPOCHREALTIME</code>
+Assignments to <code class="env">EPOCHREALTIME</code> are ignored.
+If <code class="env">EPOCHREALTIME</code>
is unset, it loses its special properties, even if
it is subsequently reset.
</p>
</dd>
-<dt id='index-EPOCHSECONDS'><span><code>EPOCHSECONDS</code><a href='#index-EPOCHSECONDS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-EPOCHSECONDS"></a><span><code class="code">EPOCHSECONDS</code><a class="copiable-link" href="#index-EPOCHSECONDS"> ¶</a></span></dt>
<dd><p>Each time this parameter is referenced, it expands to the number of seconds
since the Unix Epoch (see the documentation for the C library function
-<code>time</code> for the definition of Epoch).
-Assignments to <code>EPOCHSECONDS</code> are ignored.
-If <code>EPOCHSECONDS</code>
+<code class="code">time</code> for the definition of Epoch).
+Assignments to <code class="env">EPOCHSECONDS</code> are ignored.
+If <code class="env">EPOCHSECONDS</code>
is unset, it loses its special properties, even if
it is subsequently reset.
</p>
</dd>
-<dt id='index-EUID'><span><code>EUID</code><a href='#index-EUID' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-EUID"></a><span><code class="code">EUID</code><a class="copiable-link" href="#index-EUID"> ¶</a></span></dt>
<dd><p>The numeric effective user id of the current user. This variable
is readonly.
</p>
</dd>
-<dt id='index-EXECIGNORE'><span><code>EXECIGNORE</code><a href='#index-EXECIGNORE' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A colon-separated list of shell patterns (see <a href="#Pattern-Matching">Pattern Matching</a>)
+<dt><a id="index-EXECIGNORE"></a><span><code class="code">EXECIGNORE</code><a class="copiable-link" href="#index-EXECIGNORE"> ¶</a></span></dt>
+<dd><p>A colon-separated list of shell patterns (see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>)
defining the list of filenames to be ignored by command search using
-<code>PATH</code>.
+<code class="code">PATH</code>.
Files whose full pathnames match one of these patterns are not considered
executable files for the purposes of completion and command execution
-via <code>PATH</code> lookup.
-This does not affect the behavior of the <code>[</code>, <code>test</code>, and <code>[[</code>
+via <code class="code">PATH</code> lookup.
+This does not affect the behavior of the <code class="code">[</code>, <code class="code">test</code>, and <code class="code">[[</code>
commands.
-Full pathnames in the command hash table are not subject to <code>EXECIGNORE</code>.
+Full pathnames in the command hash table are not subject to <code class="code">EXECIGNORE</code>.
Use this variable to ignore shared library files that have the executable
bit set, but are not executable files.
-The pattern matching honors the setting of the <code>extglob</code> shell
+The pattern matching honors the setting of the <code class="code">extglob</code> shell
option.
</p>
</dd>
-<dt id='index-FCEDIT'><span><code>FCEDIT</code><a href='#index-FCEDIT' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The editor used as a default by the <samp>-e</samp> option to the <code>fc</code>
+<dt><a id="index-FCEDIT"></a><span><code class="code">FCEDIT</code><a class="copiable-link" href="#index-FCEDIT"> ¶</a></span></dt>
+<dd><p>The editor used as a default by the <samp class="option">-e</samp> option to the <code class="code">fc</code>
builtin command.
</p>
</dd>
-<dt id='index-FIGNORE'><span><code>FIGNORE</code><a href='#index-FIGNORE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-FIGNORE"></a><span><code class="code">FIGNORE</code><a class="copiable-link" href="#index-FIGNORE"> ¶</a></span></dt>
<dd><p>A colon-separated list of suffixes to ignore when performing
filename completion.
A filename whose suffix matches one of the entries in
-<code>FIGNORE</code>
+<code class="env">FIGNORE</code>
is excluded from the list of matched filenames. A sample
-value is ‘<samp>.o:~</samp>’
+value is ‘<samp class="samp">.o:~</samp>’
</p>
</dd>
-<dt id='index-FUNCNAME'><span><code>FUNCNAME</code><a href='#index-FUNCNAME' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-FUNCNAME"></a><span><code class="code">FUNCNAME</code><a class="copiable-link" href="#index-FUNCNAME"> ¶</a></span></dt>
<dd><p>An array variable containing the names of all shell functions
currently in the execution call stack.
The element with index 0 is the name of any currently-executing
shell function.
The bottom-most element (the one with the highest index)
-is <code>"main"</code>.
+is <code class="code">"main"</code>.
This variable exists only when a shell function is executing.
-Assignments to <code>FUNCNAME</code> have no effect.
-If <code>FUNCNAME</code>
+Assignments to <code class="env">FUNCNAME</code> have no effect.
+If <code class="env">FUNCNAME</code>
is unset, it loses its special properties, even if
it is subsequently reset.
</p>
-<p>This variable can be used with <code>BASH_LINENO</code> and <code>BASH_SOURCE</code>.
-Each element of <code>FUNCNAME</code> has corresponding elements in
-<code>BASH_LINENO</code> and <code>BASH_SOURCE</code> to describe the call stack.
-For instance, <code>${FUNCNAME[$i]}</code> was called from the file
-<code>${BASH_SOURCE[$i+1]}</code> at line number <code>${BASH_LINENO[$i]}</code>.
-The <code>caller</code> builtin displays the current call stack using this
+<p>This variable can be used with <code class="code">BASH_LINENO</code> and <code class="code">BASH_SOURCE</code>.
+Each element of <code class="code">FUNCNAME</code> has corresponding elements in
+<code class="code">BASH_LINENO</code> and <code class="code">BASH_SOURCE</code> to describe the call stack.
+For instance, <code class="code">${FUNCNAME[$i]}</code> was called from the file
+<code class="code">${BASH_SOURCE[$i+1]}</code> at line number <code class="code">${BASH_LINENO[$i]}</code>.
+The <code class="code">caller</code> builtin displays the current call stack using this
information.
</p>
</dd>
-<dt id='index-FUNCNEST'><span><code>FUNCNEST</code><a href='#index-FUNCNEST' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-FUNCNEST"></a><span><code class="code">FUNCNEST</code><a class="copiable-link" href="#index-FUNCNEST"> ¶</a></span></dt>
<dd><p>If set to a numeric value greater than 0, defines a maximum function
nesting level. Function invocations that exceed this nesting level
will cause the current command to abort.
</p>
</dd>
-<dt id='index-GLOBIGNORE'><span><code>GLOBIGNORE</code><a href='#index-GLOBIGNORE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-GLOBIGNORE"></a><span><code class="code">GLOBIGNORE</code><a class="copiable-link" href="#index-GLOBIGNORE"> ¶</a></span></dt>
<dd><p>A colon-separated list of patterns defining the set of file names to
be ignored by filename expansion.
If a file name matched by a filename expansion pattern also matches one
-of the patterns in <code>GLOBIGNORE</code>, it is removed from the list
+of the patterns in <code class="env">GLOBIGNORE</code>, it is removed from the list
of matches.
-The pattern matching honors the setting of the <code>extglob</code> shell
+The pattern matching honors the setting of the <code class="code">extglob</code> shell
option.
</p>
</dd>
-<dt id='index-GLOBSORT'><span><code>GLOBSORT</code><a href='#index-GLOBSORT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-GLOBSORT"></a><span><code class="code">GLOBSORT</code><a class="copiable-link" href="#index-GLOBSORT"> ¶</a></span></dt>
<dd><p>Control how the results of filename expansion are sorted.
The value of this variable specifies the sort criteria and sort order for
the results of filename expansion.
If this variable is unset or set to the null string, filename expansion
uses the historical behavior of sorting by name.
-If set, a valid value begins with an optional ‘<samp>+</samp>’, which is ignored,
-or ‘<samp>-</samp>’, which reverses the sort order from ascending to descending,
+If set, a valid value begins with an optional ‘<samp class="samp">+</samp>’, which is ignored,
+or ‘<samp class="samp">-</samp>’, which reverses the sort order from ascending to descending,
followed by a sort specifier.
The valid sort specifiers are
-‘<samp>name</samp>’,
-‘<samp>size</samp>’,
-‘<samp>mtime</samp>’,
-‘<samp>atime</samp>’,
-‘<samp>ctime</samp>’,
+‘<samp class="samp">name</samp>’,
+‘<samp class="samp">size</samp>’,
+‘<samp class="samp">mtime</samp>’,
+‘<samp class="samp">atime</samp>’,
+‘<samp class="samp">ctime</samp>’,
and
-‘<samp>blocks</samp>’,
+‘<samp class="samp">blocks</samp>’,
which sort the files on name, file size, modification time, access time,
inode change time, and number of blocks, respectively.
</p>
-<p>For example, a value of <code>-mtime</code> sorts the results in descending
+<p>For example, a value of <code class="code">-mtime</code> sorts the results in descending
order by modification time (newest first).
</p>
-<p>A sort specifier of ‘<samp>nosort</samp>’ disables sorting completely; the results
+<p>A sort specifier of ‘<samp class="samp">nosort</samp>’ disables sorting completely; the results
are returned in the order they are read from the file system,.
</p>
-<p>If the sort specifier is missing, it defaults to <var>name</var>,
-so a value of ‘<samp>+</samp>’ is equivalent to the null string,
-and a value of ‘<samp>-</samp>’ sorts by name in descending order.
+<p>If the sort specifier is missing, it defaults to <var class="var">name</var>,
+so a value of ‘<samp class="samp">+</samp>’ is equivalent to the null string,
+and a value of ‘<samp class="samp">-</samp>’ sorts by name in descending order.
</p>
<p>Any invalid value restores the historical sorting behavior.
</p>
</dd>
-<dt id='index-GROUPS'><span><code>GROUPS</code><a href='#index-GROUPS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-GROUPS"></a><span><code class="code">GROUPS</code><a class="copiable-link" href="#index-GROUPS"> ¶</a></span></dt>
<dd><p>An array variable containing the list of groups of which the current
user is a member.
-Assignments to <code>GROUPS</code> have no effect.
-If <code>GROUPS</code>
+Assignments to <code class="env">GROUPS</code> have no effect.
+If <code class="env">GROUPS</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-histchars'><span><code>histchars</code><a href='#index-histchars' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-histchars"></a><span><code class="code">histchars</code><a class="copiable-link" href="#index-histchars"> ¶</a></span></dt>
<dd><p>Up to three characters which control history expansion, quick
-substitution, and tokenization (see <a href="#History-Interaction">History Expansion</a>).
+substitution, and tokenization (see <a class="pxref" href="#History-Interaction">History Expansion</a>).
The first character is the
-<em>history expansion</em> character, that is, the character which signifies the
-start of a history expansion, normally ‘<samp>!</samp>’.
+<em class="dfn">history expansion</em> character, that is, the character which signifies the
+start of a history expansion, normally ‘<samp class="samp">!</samp>’.
The second character is the
character which signifies "quick substitution" when seen as the first
-character on a line, normally ‘<samp>^</samp>’.
+character on a line, normally ‘<samp class="samp">^</samp>’.
The optional third character is the
character which indicates that the remainder of the line is a comment when
-found as the first character of a word, usually ‘<samp>#</samp>’.
+found as the first character of a word, usually ‘<samp class="samp">#</samp>’.
The history
comment character causes history substitution to be skipped for the
remaining words on the line.
parser to treat the rest of the line as a comment.
</p>
</dd>
-<dt id='index-HISTCMD'><span><code>HISTCMD</code><a href='#index-HISTCMD' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTCMD"></a><span><code class="code">HISTCMD</code><a class="copiable-link" href="#index-HISTCMD"> ¶</a></span></dt>
<dd><p>The history number, or index in the history list, of the current
command.
-Assignments to <code>HISTCMD</code> are ignored.
-If <code>HISTCMD</code>
+Assignments to <code class="env">HISTCMD</code> are ignored.
+If <code class="env">HISTCMD</code>
is unset, it loses its special properties,
even if it is subsequently reset.
</p>
</dd>
-<dt id='index-HISTCONTROL'><span><code>HISTCONTROL</code><a href='#index-HISTCONTROL' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTCONTROL"></a><span><code class="code">HISTCONTROL</code><a class="copiable-link" href="#index-HISTCONTROL"> ¶</a></span></dt>
<dd><p>A colon-separated list of values controlling how commands are saved on
the history list.
-If the list of values includes ‘<samp>ignorespace</samp>’, lines which begin
+If the list of values includes ‘<samp class="samp">ignorespace</samp>’, lines which begin
with a space character are not saved in the history list.
-A value of ‘<samp>ignoredups</samp>’ causes lines which match the previous
+A value of ‘<samp class="samp">ignoredups</samp>’ causes lines which match the previous
history entry to not be saved.
-A value of ‘<samp>ignoreboth</samp>’ is shorthand for
-‘<samp>ignorespace</samp>’ and ‘<samp>ignoredups</samp>’.
-A value of ‘<samp>erasedups</samp>’ causes all previous lines matching the
+A value of ‘<samp class="samp">ignoreboth</samp>’ is shorthand for
+‘<samp class="samp">ignorespace</samp>’ and ‘<samp class="samp">ignoredups</samp>’.
+A value of ‘<samp class="samp">erasedups</samp>’ causes all previous lines matching the
current line to be removed from the history list before that line
is saved.
Any value not in the above list is ignored.
-If <code>HISTCONTROL</code> is unset, or does not include a valid value,
+If <code class="env">HISTCONTROL</code> is unset, or does not include a valid value,
all lines read by the shell parser are saved on the history list,
-subject to the value of <code>HISTIGNORE</code>.
+subject to the value of <code class="env">HISTIGNORE</code>.
The second and subsequent lines of a multi-line compound command are
not tested, and are added to the history regardless of the value of
-<code>HISTCONTROL</code>.
+<code class="env">HISTCONTROL</code>.
</p>
</dd>
-<dt id='index-HISTFILE'><span><code>HISTFILE</code><a href='#index-HISTFILE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTFILE"></a><span><code class="code">HISTFILE</code><a class="copiable-link" href="#index-HISTFILE"> ¶</a></span></dt>
<dd><p>The name of the file to which the command history is saved.
-Bash assigns a default value of <samp>~/.bash_history</samp>.
-If <code>HISTFILE</code> is unset or null,
+Bash assigns a default value of <samp class="file">~/.bash_history</samp>.
+If <code class="env">HISTFILE</code> is unset or null,
the command history is not saved when a shell exits.
</p>
</dd>
-<dt id='index-HISTFILESIZE'><span><code>HISTFILESIZE</code><a href='#index-HISTFILESIZE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTFILESIZE"></a><span><code class="code">HISTFILESIZE</code><a class="copiable-link" href="#index-HISTFILESIZE"> ¶</a></span></dt>
<dd><p>The maximum number of lines contained in the history file.
When this variable is assigned a value, the history file is truncated,
if necessary, to contain no more than that number of lines
writing it when a shell exits.
If the value is 0, the history file is truncated to zero size.
Non-numeric values and numeric values less than zero inhibit truncation.
-The shell sets the default value to the value of <code>HISTSIZE</code>
+The shell sets the default value to the value of <code class="env">HISTSIZE</code>
after reading any startup files.
</p>
</dd>
-<dt id='index-HISTIGNORE'><span><code>HISTIGNORE</code><a href='#index-HISTIGNORE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTIGNORE"></a><span><code class="code">HISTIGNORE</code><a class="copiable-link" href="#index-HISTIGNORE"> ¶</a></span></dt>
<dd><p>A colon-separated list of patterns used to decide which command
-lines should be saved on the history list. Each pattern is
+lines should be saved on the history list.
+Each pattern is
anchored at the beginning of the line and must match the complete
-line (no implicit ‘<samp>*</samp>’ is appended). Each pattern is tested
-against the line after the checks specified by <code>HISTCONTROL</code>
+line (Bash will not implicitly append a ‘<samp class="samp">*</samp>’).
+Each pattern is tested
+against the line after the checks specified by <code class="env">HISTCONTROL</code>
are applied. In addition to the normal shell pattern matching
-characters, ‘<samp>&</samp>’ matches the previous history line. ‘<samp>&</samp>’
+characters, ‘<samp class="samp">&</samp>’ matches the previous history line. ‘<samp class="samp">&</samp>’
may be escaped using a backslash; the backslash is removed
before attempting a match.
The second and subsequent lines of a multi-line compound command are
not tested, and are added to the history regardless of the value of
-<code>HISTIGNORE</code>.
-The pattern matching honors the setting of the <code>extglob</code> shell
+<code class="env">HISTIGNORE</code>.
+The pattern matching honors the setting of the <code class="code">extglob</code> shell
option.
</p>
-<p><code>HISTIGNORE</code> subsumes the function of <code>HISTCONTROL</code>. A
-pattern of ‘<samp>&</samp>’ is identical to <code>ignoredups</code>, and a
-pattern of ‘<samp>[ ]*</samp>’ is identical to <code>ignorespace</code>.
+<p><code class="env">HISTIGNORE</code> subsumes the function of <code class="env">HISTCONTROL</code>. A
+pattern of ‘<samp class="samp">&</samp>’ is identical to <code class="code">ignoredups</code>, and a
+pattern of ‘<samp class="samp">[ ]*</samp>’ is identical to <code class="code">ignorespace</code>.
Combining these two patterns, separating them with a colon,
-provides the functionality of <code>ignoreboth</code>.
+provides the functionality of <code class="code">ignoreboth</code>.
</p>
</dd>
-<dt id='index-HISTSIZE'><span><code>HISTSIZE</code><a href='#index-HISTSIZE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTSIZE"></a><span><code class="code">HISTSIZE</code><a class="copiable-link" href="#index-HISTSIZE"> ¶</a></span></dt>
<dd><p>The maximum number of commands to remember on the history list.
If the value is 0, commands are not saved in the history list.
Numeric values less than zero result in every command being saved
The shell sets the default value to 500 after reading any startup files.
</p>
</dd>
-<dt id='index-HISTTIMEFORMAT'><span><code>HISTTIMEFORMAT</code><a href='#index-HISTTIMEFORMAT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HISTTIMEFORMAT"></a><span><code class="code">HISTTIMEFORMAT</code><a class="copiable-link" href="#index-HISTTIMEFORMAT"> ¶</a></span></dt>
<dd><p>If this variable is set and not null, its value is used as a format string
-for <code>strftime</code> to print the time stamp associated with each history
-entry displayed by the <code>history</code> builtin.
+for <code class="code">strftime</code>(3) to print the time stamp associated with each history
+entry displayed by the <code class="code">history</code> builtin.
If this variable is set, time stamps are written to the history file so
they may be preserved across shell sessions.
This uses the history comment character to distinguish timestamps from
other history lines.
</p>
</dd>
-<dt id='index-HOSTFILE'><span><code>HOSTFILE</code><a href='#index-HOSTFILE' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Contains the name of a file in the same format as <samp>/etc/hosts</samp> that
+<dt><a id="index-HOSTFILE"></a><span><code class="code">HOSTFILE</code><a class="copiable-link" href="#index-HOSTFILE"> ¶</a></span></dt>
+<dd><p>Contains the name of a file in the same format as <samp class="file">/etc/hosts</samp> that
should be read when the shell needs to complete a hostname.
The list of possible hostname completions may be changed while the shell
is running;
the next time hostname completion is attempted after the
value is changed, Bash adds the contents of the new file to the
existing list.
-If <code>HOSTFILE</code> is set, but has no value, or does not name a readable file,
+If <code class="env">HOSTFILE</code> is set, but has no value, or does not name a readable file,
Bash attempts to read
-<samp>/etc/hosts</samp> to obtain the list of possible hostname completions.
-When <code>HOSTFILE</code> is unset, the hostname list is cleared.
+<samp class="file">/etc/hosts</samp> to obtain the list of possible hostname completions.
+When <code class="env">HOSTFILE</code> is unset, the hostname list is cleared.
</p>
</dd>
-<dt id='index-HOSTNAME'><span><code>HOSTNAME</code><a href='#index-HOSTNAME' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HOSTNAME"></a><span><code class="code">HOSTNAME</code><a class="copiable-link" href="#index-HOSTNAME"> ¶</a></span></dt>
<dd><p>The name of the current host.
</p>
</dd>
-<dt id='index-HOSTTYPE'><span><code>HOSTTYPE</code><a href='#index-HOSTTYPE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-HOSTTYPE"></a><span><code class="code">HOSTTYPE</code><a class="copiable-link" href="#index-HOSTTYPE"> ¶</a></span></dt>
<dd><p>A string describing the machine Bash is running on.
</p>
</dd>
-<dt id='index-IGNOREEOF'><span><code>IGNOREEOF</code><a href='#index-IGNOREEOF' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Controls the action of the shell on receipt of an <code>EOF</code> character
+<dt><a id="index-IGNOREEOF"></a><span><code class="code">IGNOREEOF</code><a class="copiable-link" href="#index-IGNOREEOF"> ¶</a></span></dt>
+<dd><p>Controls the action of the shell on receipt of an <code class="code">EOF</code> character
as the sole input. If set, the value denotes the number
-of consecutive <code>EOF</code> characters that can be read as the
+of consecutive <code class="code">EOF</code> characters that can be read as the
first character on an input line
before the shell will exit. If the variable exists but does not
have a numeric value, or has no value, then the default is 10.
-If the variable does not exist, then <code>EOF</code> signifies the end of
+If the variable does not exist, then <code class="code">EOF</code> signifies the end of
input to the shell. This is only in effect for interactive shells.
</p>
</dd>
-<dt id='index-INPUTRC'><span><code>INPUTRC</code><a href='#index-INPUTRC' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-INPUTRC"></a><span><code class="code">INPUTRC</code><a class="copiable-link" href="#index-INPUTRC"> ¶</a></span></dt>
<dd><p>The name of the Readline initialization file, overriding the default
-of <samp>~/.inputrc</samp>.
+of <samp class="file">~/.inputrc</samp>.
</p>
</dd>
-<dt id='index-INSIDE_005fEMACS'><span><code>INSIDE_EMACS</code><a href='#index-INSIDE_005fEMACS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-INSIDE_005fEMACS"></a><span><code class="code">INSIDE_EMACS</code><a class="copiable-link" href="#index-INSIDE_005fEMACS"> ¶</a></span></dt>
<dd><p>If Bash finds this variable in the environment when the shell
starts, it assumes that the shell is running in an Emacs shell buffer
-and may disable line editing depending on the value of <code>TERM</code>.
+and may disable line editing depending on the value of <code class="env">TERM</code>.
</p>
</dd>
-<dt id='index-LANG-1'><span><code>LANG</code><a href='#index-LANG-1' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LANG-1"></a><span><code class="code">LANG</code><a class="copiable-link" href="#index-LANG-1"> ¶</a></span></dt>
<dd><p>Used to determine the locale category for any category not specifically
-selected with a variable starting with <code>LC_</code>.
+selected with a variable starting with <code class="code">LC_</code>.
</p>
</dd>
-<dt id='index-LC_005fALL'><span><code>LC_ALL</code><a href='#index-LC_005fALL' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>This variable overrides the value of <code>LANG</code> and any other
-<code>LC_</code> variable specifying a locale category.
+<dt><a id="index-LC_005fALL"></a><span><code class="code">LC_ALL</code><a class="copiable-link" href="#index-LC_005fALL"> ¶</a></span></dt>
+<dd><p>This variable overrides the value of <code class="env">LANG</code> and any other
+<code class="code">LC_</code> variable specifying a locale category.
</p>
</dd>
-<dt id='index-LC_005fCOLLATE'><span><code>LC_COLLATE</code><a href='#index-LC_005fCOLLATE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LC_005fCOLLATE"></a><span><code class="code">LC_COLLATE</code><a class="copiable-link" href="#index-LC_005fCOLLATE"> ¶</a></span></dt>
<dd><p>This variable determines the collation order used when sorting the
results of filename expansion, and
determines the behavior of range expressions, equivalence classes,
and collating sequences within filename expansion and pattern matching
-(see <a href="#Filename-Expansion">Filename Expansion</a>).
+(see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>).
</p>
</dd>
-<dt id='index-LC_005fCTYPE'><span><code>LC_CTYPE</code><a href='#index-LC_005fCTYPE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LC_005fCTYPE"></a><span><code class="code">LC_CTYPE</code><a class="copiable-link" href="#index-LC_005fCTYPE"> ¶</a></span></dt>
<dd><p>This variable determines the interpretation of characters and the
behavior of character classes within filename expansion and pattern
-matching (see <a href="#Filename-Expansion">Filename Expansion</a>).
+matching (see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>).
</p>
</dd>
-<dt id='index-LC_005fMESSAGES-1'><span><code>LC_MESSAGES</code><a href='#index-LC_005fMESSAGES-1' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LC_005fMESSAGES-1"></a><span><code class="code">LC_MESSAGES</code><a class="copiable-link" href="#index-LC_005fMESSAGES-1"> ¶</a></span></dt>
<dd><p>This variable determines the locale used to translate double-quoted
-strings preceded by a ‘<samp>$</samp>’ (see <a href="#Locale-Translation">Locale-Specific Translation</a>).
+strings preceded by a ‘<samp class="samp">$</samp>’ (see <a class="pxref" href="#Locale-Translation">Locale-Specific Translation</a>).
</p>
</dd>
-<dt id='index-LC_005fNUMERIC'><span><code>LC_NUMERIC</code><a href='#index-LC_005fNUMERIC' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LC_005fNUMERIC"></a><span><code class="code">LC_NUMERIC</code><a class="copiable-link" href="#index-LC_005fNUMERIC"> ¶</a></span></dt>
<dd><p>This variable determines the locale category used for number formatting.
</p>
</dd>
-<dt id='index-LC_005fTIME'><span><code>LC_TIME</code><a href='#index-LC_005fTIME' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LC_005fTIME"></a><span><code class="code">LC_TIME</code><a class="copiable-link" href="#index-LC_005fTIME"> ¶</a></span></dt>
<dd><p>This variable determines the locale category used for data and time
formatting.
</p>
</dd>
-<dt id='index-LINENO'><span><code>LINENO</code><a href='#index-LINENO' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-LINENO"></a><span><code class="code">LINENO</code><a class="copiable-link" href="#index-LINENO"> ¶</a></span></dt>
<dd><p>The line number in the script or shell function currently executing.
-If <code>LINENO</code>
+If <code class="env">LINENO</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-LINES'><span><code>LINES</code><a href='#index-LINES' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Used by the <code>select</code> command to determine the column length
+<dt><a id="index-LINES"></a><span><code class="code">LINES</code><a class="copiable-link" href="#index-LINES"> ¶</a></span></dt>
+<dd><p>Used by the <code class="code">select</code> command to determine the column length
for printing selection lists.
-Automatically set if the <code>checkwinsize</code> option is enabled
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), or in an interactive shell upon receipt of a
-<code>SIGWINCH</code>.
+Automatically set if the <code class="code">checkwinsize</code> option is enabled
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>), or in an interactive shell upon receipt of a
+<code class="code">SIGWINCH</code>.
</p>
</dd>
-<dt id='index-MACHTYPE'><span><code>MACHTYPE</code><a href='#index-MACHTYPE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-MACHTYPE"></a><span><code class="code">MACHTYPE</code><a class="copiable-link" href="#index-MACHTYPE"> ¶</a></span></dt>
<dd><p>A string that fully describes the system type on which Bash
-is executing, in the standard <small>GNU</small> <var>cpu-company-system</var> format.
+is executing, in the standard <small class="sc">GNU</small> <var class="var">cpu-company-system</var> format.
</p>
</dd>
-<dt id='index-MAILCHECK'><span><code>MAILCHECK</code><a href='#index-MAILCHECK' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-MAILCHECK"></a><span><code class="code">MAILCHECK</code><a class="copiable-link" href="#index-MAILCHECK"> ¶</a></span></dt>
<dd><p>How often (in seconds) that the shell should check for mail in the
-files specified in the <code>MAILPATH</code> or <code>MAIL</code> variables.
+files specified in the <code class="env">MAILPATH</code> or <code class="env">MAIL</code> variables.
The default is 60 seconds. When it is time to check
for mail, the shell does so before displaying the primary prompt.
If this variable is unset, or set to a value that is not a number
greater than or equal to zero, the shell disables mail checking.
</p>
</dd>
-<dt id='index-MAPFILE'><span><code>MAPFILE</code><a href='#index-MAPFILE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-MAPFILE"></a><span><code class="code">MAPFILE</code><a class="copiable-link" href="#index-MAPFILE"> ¶</a></span></dt>
<dd><p>An array variable created to hold the text read by the
-<code>mapfile</code> builtin when no variable name is supplied.
+<code class="code">mapfile</code> builtin when no variable name is supplied.
</p>
</dd>
-<dt id='index-OLDPWD'><span><code>OLDPWD</code><a href='#index-OLDPWD' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The previous working directory as set by the <code>cd</code> builtin.
+<dt><a id="index-OLDPWD"></a><span><code class="code">OLDPWD</code><a class="copiable-link" href="#index-OLDPWD"> ¶</a></span></dt>
+<dd><p>The previous working directory as set by the <code class="code">cd</code> builtin.
</p>
</dd>
-<dt id='index-OPTERR'><span><code>OPTERR</code><a href='#index-OPTERR' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-OPTERR"></a><span><code class="code">OPTERR</code><a class="copiable-link" href="#index-OPTERR"> ¶</a></span></dt>
<dd><p>If set to the value 1, Bash displays error messages
-generated by the <code>getopts</code> builtin command.
+generated by the <code class="code">getopts</code> builtin command.
</p>
</dd>
-<dt id='index-OSTYPE'><span><code>OSTYPE</code><a href='#index-OSTYPE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-OSTYPE"></a><span><code class="code">OSTYPE</code><a class="copiable-link" href="#index-OSTYPE"> ¶</a></span></dt>
<dd><p>A string describing the operating system Bash is running on.
</p>
</dd>
-<dt id='index-PIPESTATUS'><span><code>PIPESTATUS</code><a href='#index-PIPESTATUS' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>An array variable (see <a href="#Arrays">Arrays</a>)
+<dt><a id="index-PIPESTATUS"></a><span><code class="code">PIPESTATUS</code><a class="copiable-link" href="#index-PIPESTATUS"> ¶</a></span></dt>
+<dd><p>An array variable (see <a class="pxref" href="#Arrays">Arrays</a>)
containing a list of exit status values from the processes
in the most-recently-executed foreground pipeline (which may
contain only a single command).
</p>
</dd>
-<dt id='index-POSIXLY_005fCORRECT'><span><code>POSIXLY_CORRECT</code><a href='#index-POSIXLY_005fCORRECT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-POSIXLY_005fCORRECT"></a><span><code class="code">POSIXLY_CORRECT</code><a class="copiable-link" href="#index-POSIXLY_005fCORRECT"> ¶</a></span></dt>
<dd><p>If this variable is in the environment when Bash starts, the shell
-enters <small>POSIX</small> mode (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>) before reading the
-startup files, as if the <samp>--posix</samp> invocation option had been supplied.
-If it is set while the shell is running, Bash enables <small>POSIX</small> mode,
+enters <small class="sc">POSIX</small> mode (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>) before reading the
+startup files, as if the <samp class="option">--posix</samp> invocation option had been supplied.
+If it is set while the shell is running, Bash enables <small class="sc">POSIX</small> mode,
as if the command
</p><div class="example">
-<pre class="example"><code>set -o posix</code>
+<pre class="example-preformatted"><code class="code">set -o posix</code>
</pre></div>
<p>had been executed.
-When the shell enters <small>POSIX</small> mode, it sets this variable if it was
+When the shell enters <small class="sc">POSIX</small> mode, it sets this variable if it was
not already set.
</p>
</dd>
-<dt id='index-PPID'><span><code>PPID</code><a href='#index-PPID' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The process <small>ID</small> of the shell’s parent process. This variable
+<dt><a id="index-PPID"></a><span><code class="code">PPID</code><a class="copiable-link" href="#index-PPID"> ¶</a></span></dt>
+<dd><p>The process <small class="sc">ID</small> of the shell’s parent process. This variable
is readonly.
</p>
</dd>
-<dt id='index-PROMPT_005fCOMMAND'><span><code>PROMPT_COMMAND</code><a href='#index-PROMPT_005fCOMMAND' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-PROMPT_005fCOMMAND"></a><span><code class="code">PROMPT_COMMAND</code><a class="copiable-link" href="#index-PROMPT_005fCOMMAND"> ¶</a></span></dt>
<dd><p>If this variable is set, and is an array,
the value of each set element is interpreted as a command to execute
-before printing the primary prompt (<code>$PS1</code>).
+before printing the primary prompt (<code class="env">$PS1</code>).
If this is set but not an array variable,
its value is used as a command to execute instead.
</p>
</dd>
-<dt id='index-PROMPT_005fDIRTRIM'><span><code>PROMPT_DIRTRIM</code><a href='#index-PROMPT_005fDIRTRIM' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-PROMPT_005fDIRTRIM"></a><span><code class="code">PROMPT_DIRTRIM</code><a class="copiable-link" href="#index-PROMPT_005fDIRTRIM"> ¶</a></span></dt>
<dd><p>If set to a number greater than zero, the value is used as the number of
-trailing directory components to retain when expanding the <code>\w</code> and
-<code>\W</code> prompt string escapes (see <a href="#Controlling-the-Prompt">Controlling the Prompt</a>).
+trailing directory components to retain when expanding the <code class="code">\w</code> and
+<code class="code">\W</code> prompt string escapes (see <a class="pxref" href="#Controlling-the-Prompt">Controlling the Prompt</a>).
Characters removed are replaced with an ellipsis.
</p>
</dd>
-<dt id='index-PS0'><span><code>PS0</code><a href='#index-PS0' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The value of this parameter is expanded like <code>PS1</code>
+<dt><a id="index-PS0"></a><span><code class="code">PS0</code><a class="copiable-link" href="#index-PS0"> ¶</a></span></dt>
+<dd><p>The value of this parameter is expanded like <code class="env">PS1</code>
and displayed by interactive shells after reading a command
and before the command is executed.
</p>
</dd>
-<dt id='index-PS3'><span><code>PS3</code><a href='#index-PS3' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-PS3"></a><span><code class="code">PS3</code><a class="copiable-link" href="#index-PS3"> ¶</a></span></dt>
<dd><p>The value of this variable is used as the prompt for the
-<code>select</code> command. If this variable is not set, the
-<code>select</code> command prompts with ‘<samp>#? </samp>’
+<code class="code">select</code> command. If this variable is not set, the
+<code class="code">select</code> command prompts with ‘<samp class="samp">#? </samp>’
</p>
</dd>
-<dt id='index-PS4'><span><code>PS4</code><a href='#index-PS4' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The value of this parameter is expanded like <code>PS1</code>
+<dt><a id="index-PS4"></a><span><code class="code">PS4</code><a class="copiable-link" href="#index-PS4"> ¶</a></span></dt>
+<dd><p>The value of this parameter is expanded like <code class="env">PS1</code>
and the expanded value is the prompt printed before the command line
-is echoed when the <samp>-x</samp> option is set (see <a href="#The-Set-Builtin">The Set Builtin</a>).
+is echoed when the <samp class="option">-x</samp> option is set (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
The first character of the expanded value is replicated multiple times,
as necessary, to indicate multiple levels of indirection.
-The default is ‘<samp>+ </samp>’.
+The default is ‘<samp class="samp">+ </samp>’.
</p>
</dd>
-<dt id='index-PWD'><span><code>PWD</code><a href='#index-PWD' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The current working directory as set by the <code>cd</code> builtin.
+<dt><a id="index-PWD"></a><span><code class="code">PWD</code><a class="copiable-link" href="#index-PWD"> ¶</a></span></dt>
+<dd><p>The current working directory as set by the <code class="code">cd</code> builtin.
</p>
</dd>
-<dt id='index-RANDOM'><span><code>RANDOM</code><a href='#index-RANDOM' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-RANDOM"></a><span><code class="code">RANDOM</code><a class="copiable-link" href="#index-RANDOM"> ¶</a></span></dt>
<dd><p>Each time this parameter is referenced, it expands to a random integer
between 0 and 32767. Assigning a value to this
variable seeds the random number generator.
-If <code>RANDOM</code>
+If <code class="env">RANDOM</code>
is unset, it loses its special properties, even if it is
subsequently reset.
</p>
</dd>
-<dt id='index-READLINE_005fARGUMENT'><span><code>READLINE_ARGUMENT</code><a href='#index-READLINE_005fARGUMENT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-READLINE_005fARGUMENT"></a><span><code class="code">READLINE_ARGUMENT</code><a class="copiable-link" href="#index-READLINE_005fARGUMENT"> ¶</a></span></dt>
<dd><p>Any numeric argument given to a Readline command that was defined using
-‘<samp>bind -x</samp>’ (see <a href="#Bash-Builtins">Bash Builtin Commands</a>
+‘<samp class="samp">bind -x</samp>’ (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>
when it was invoked.
</p>
</dd>
-<dt id='index-READLINE_005fLINE'><span><code>READLINE_LINE</code><a href='#index-READLINE_005fLINE' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-READLINE_005fLINE"></a><span><code class="code">READLINE_LINE</code><a class="copiable-link" href="#index-READLINE_005fLINE"> ¶</a></span></dt>
<dd><p>The contents of the Readline line buffer, for use
-with ‘<samp>bind -x</samp>’ (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+with ‘<samp class="samp">bind -x</samp>’ (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p>
</dd>
-<dt id='index-READLINE_005fMARK'><span><code>READLINE_MARK</code><a href='#index-READLINE_005fMARK' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The position of the <em>mark</em> (saved insertion point) in the
+<dt><a id="index-READLINE_005fMARK"></a><span><code class="code">READLINE_MARK</code><a class="copiable-link" href="#index-READLINE_005fMARK"> ¶</a></span></dt>
+<dd><p>The position of the <em class="dfn">mark</em> (saved insertion point) in the
Readline line buffer, for use
-with ‘<samp>bind -x</samp>’ (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+with ‘<samp class="samp">bind -x</samp>’ (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
The characters between the insertion point and the mark are often
-called the <em>region</em>.
+called the <em class="dfn">region</em>.
</p>
</dd>
-<dt id='index-READLINE_005fPOINT'><span><code>READLINE_POINT</code><a href='#index-READLINE_005fPOINT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-READLINE_005fPOINT"></a><span><code class="code">READLINE_POINT</code><a class="copiable-link" href="#index-READLINE_005fPOINT"> ¶</a></span></dt>
<dd><p>The position of the insertion point in the Readline line buffer, for use
-with ‘<samp>bind -x</samp>’ (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+with ‘<samp class="samp">bind -x</samp>’ (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p>
</dd>
-<dt id='index-REPLY'><span><code>REPLY</code><a href='#index-REPLY' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The default variable for the <code>read</code> builtin.
+<dt><a id="index-REPLY"></a><span><code class="code">REPLY</code><a class="copiable-link" href="#index-REPLY"> ¶</a></span></dt>
+<dd><p>The default variable for the <code class="code">read</code> builtin.
</p>
</dd>
-<dt id='index-SECONDS'><span><code>SECONDS</code><a href='#index-SECONDS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-SECONDS"></a><span><code class="code">SECONDS</code><a class="copiable-link" href="#index-SECONDS"> ¶</a></span></dt>
<dd><p>This variable expands to the number of seconds since the shell was started.
Assignment to this variable resets the count to the value assigned, and the
expanded value becomes the value assigned plus the number of seconds
since the assignment.
The number of seconds at shell invocation and the current time are always
determined by querying the system clock.
-If <code>SECONDS</code>
+If <code class="env">SECONDS</code>
is unset, it loses its special properties,
even if it is subsequently reset.
</p>
</dd>
-<dt id='index-SHELL'><span><code>SHELL</code><a href='#index-SHELL' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-SHELL"></a><span><code class="code">SHELL</code><a class="copiable-link" href="#index-SHELL"> ¶</a></span></dt>
<dd><p>This environment variable expands to the full pathname to the shell.
If it is not set when the shell starts,
Bash assigns to it the full pathname of the current user’s login shell.
</p>
</dd>
-<dt id='index-SHELLOPTS'><span><code>SHELLOPTS</code><a href='#index-SHELLOPTS' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-SHELLOPTS"></a><span><code class="code">SHELLOPTS</code><a class="copiable-link" href="#index-SHELLOPTS"> ¶</a></span></dt>
<dd><p>A colon-separated list of enabled shell options. Each word in
-the list is a valid argument for the <samp>-o</samp> option to the
-<code>set</code> builtin command (see <a href="#The-Set-Builtin">The Set Builtin</a>).
-The options appearing in <code>SHELLOPTS</code> are those reported
-as ‘<samp>on</samp>’ by ‘<samp>set -o</samp>’.
+the list is a valid argument for the <samp class="option">-o</samp> option to the
+<code class="code">set</code> builtin command (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
+The options appearing in <code class="env">SHELLOPTS</code> are those reported
+as ‘<samp class="samp">on</samp>’ by ‘<samp class="samp">set -o</samp>’.
If this variable is in the environment when Bash
starts up, each shell option in the list will be enabled before
reading any startup files. This variable is readonly.
</p>
</dd>
-<dt id='index-SHLVL'><span><code>SHLVL</code><a href='#index-SHLVL' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-SHLVL"></a><span><code class="code">SHLVL</code><a class="copiable-link" href="#index-SHLVL"> ¶</a></span></dt>
<dd><p>Incremented by one each time a new instance of Bash is started. This is
intended to be a count of how deeply your Bash shells are nested.
</p>
</dd>
-<dt id='index-SRANDOM'><span><code>SRANDOM</code><a href='#index-SRANDOM' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-SRANDOM"></a><span><code class="code">SRANDOM</code><a class="copiable-link" href="#index-SRANDOM"> ¶</a></span></dt>
<dd><p>This variable expands to a 32-bit pseudo-random number each time it is
referenced. The random number generator is not linear on systems that
-support <samp>/dev/urandom</samp> or <code>arc4random</code>, so each returned number
+support <samp class="file">/dev/urandom</samp> or <code class="code">arc4random</code>, so each returned number
has no relationship to the numbers preceding it.
The random number generator cannot be seeded, so assignments to this
variable have no effect.
-If <code>SRANDOM</code>
+If <code class="env">SRANDOM</code>
is unset, it loses its special properties,
even if it is subsequently reset.
</p>
</dd>
-<dt id='index-TIMEFORMAT'><span><code>TIMEFORMAT</code><a href='#index-TIMEFORMAT' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-TIMEFORMAT"></a><span><code class="code">TIMEFORMAT</code><a class="copiable-link" href="#index-TIMEFORMAT"> ¶</a></span></dt>
<dd><p>The value of this parameter is used as a format string specifying
-how the timing information for pipelines prefixed with the <code>time</code>
+how the timing information for pipelines prefixed with the <code class="code">time</code>
reserved word should be displayed.
-The ‘<samp>%</samp>’ character introduces an
+The ‘<samp class="samp">%</samp>’ character introduces an
escape sequence that is expanded to a time value or other
information.
The escape sequences and their meanings are as
-follows; the braces denote optional portions.
+follows; the brackets denote optional portions.
</p>
-<dl compact="compact">
-<dt><span><code>%%</code></span></dt>
-<dd><p>A literal ‘<samp>%</samp>’.
+<dl class="table">
+<dt><code class="code">%%</code></dt>
+<dd><p>A literal ‘<samp class="samp">%</samp>’.
</p>
</dd>
-<dt><span><code>%[<var>p</var>][l]R</code></span></dt>
+<dt><code class="code">%[<var class="var">p</var>][l]R</code></dt>
<dd><p>The elapsed time in seconds.
</p>
</dd>
-<dt><span><code>%[<var>p</var>][l]U</code></span></dt>
+<dt><code class="code">%[<var class="var">p</var>][l]U</code></dt>
<dd><p>The number of CPU seconds spent in user mode.
</p>
</dd>
-<dt><span><code>%[<var>p</var>][l]S</code></span></dt>
+<dt><code class="code">%[<var class="var">p</var>][l]S</code></dt>
<dd><p>The number of CPU seconds spent in system mode.
</p>
</dd>
-<dt><span><code>%P</code></span></dt>
+<dt><code class="code">%P</code></dt>
<dd><p>The CPU percentage, computed as (%U + %S) / %R.
</p></dd>
</dl>
-<p>The optional <var>p</var> is a digit specifying the precision, the number of
+<p>The optional <var class="var">p</var> is a digit specifying the precision, the number of
fractional digits after a decimal point.
A value of 0 causes no decimal point or fraction to be output.
At most six places after the decimal point may be specified;
-values of <var>p</var> greater than 6 are changed to 6.
-If <var>p</var> is not specified, the value 3 is used.
+values of <var class="var">p</var> greater than 6 are changed to 6.
+If <var class="var">p</var> is not specified, the value 3 is used.
</p>
-<p>The optional <code>l</code> specifies a longer format, including minutes, of
-the form <var>MM</var>m<var>SS</var>.<var>FF</var>s.
-The value of <var>p</var> determines whether or not the fraction is included.
+<p>The optional <code class="code">l</code> specifies a longer format, including minutes, of
+the form <var class="var">MM</var>m<var class="var">SS</var>.<var class="var">FF</var>s.
+The value of <var class="var">p</var> determines whether or not the fraction is included.
</p>
<p>If this variable is not set, Bash acts as if it had the value
</p><div class="example">
-<pre class="example"><code>$'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'</code>
+<pre class="example-preformatted"><code class="code">$'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'</code>
</pre></div>
<p>If the value is null, Bash does not display any timing information.
A trailing newline is added when the format string is displayed.
</p>
</dd>
-<dt id='index-TMOUT'><span><code>TMOUT</code><a href='#index-TMOUT' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to a value greater than zero, <code>TMOUT</code> is treated as the
-default timeout for the <code>read</code> builtin (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
-The <code>select</code> command (see <a href="#Conditional-Constructs">Conditional Constructs</a>) terminates
-if input does not arrive after <code>TMOUT</code> seconds when input is coming
+<dt><a id="index-TMOUT"></a><span><code class="code">TMOUT</code><a class="copiable-link" href="#index-TMOUT"> ¶</a></span></dt>
+<dd><p>If set to a value greater than zero, <code class="code">TMOUT</code> is treated as the
+default timeout for the <code class="code">read</code> builtin (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
+The <code class="code">select</code> command (see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>) terminates
+if input does not arrive after <code class="code">TMOUT</code> seconds when input is coming
from a terminal.
</p>
<p>In an interactive shell, the value is interpreted as
line of input does not arrive.
</p>
</dd>
-<dt id='index-TMPDIR'><span><code>TMPDIR</code><a href='#index-TMPDIR' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-TMPDIR"></a><span><code class="code">TMPDIR</code><a class="copiable-link" href="#index-TMPDIR"> ¶</a></span></dt>
<dd><p>If set, Bash uses its value as the name of a directory in which
Bash creates temporary files for the shell’s use.
</p>
</dd>
-<dt id='index-UID'><span><code>UID</code><a href='#index-UID' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-UID"></a><span><code class="code">UID</code><a class="copiable-link" href="#index-UID"> ¶</a></span></dt>
<dd><p>The numeric real user id of the current user. This variable is readonly.
</p>
</dd>
<hr>
</div>
</div>
-<div class="chapter" id="Bash-Features">
-<div class="header">
+<div class="chapter-level-extent" id="Bash-Features">
+<div class="nav-panel">
<p>
Next: <a href="#Job-Control" accesskey="n" rel="next">Job Control</a>, Previous: <a href="#Shell-Variables" accesskey="p" rel="prev">Shell Variables</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-Features-2"></span><h2 class="chapter">6 Bash Features</h2>
+<h2 class="chapter" id="Bash-Features-2"><span>6 Bash Features<a class="copiable-link" href="#Bash-Features-2"> ¶</a></span></h2>
<p>This chapter describes features unique to Bash.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Invoking-Bash" accesskey="1">Invoking Bash</a></li>
<li><a href="#Bash-Startup-Files" accesskey="2">Bash Startup Files</a></li>
<li><a href="#Interactive-Shells" accesskey="3">Interactive Shells</a></li>
<li><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></li>
</ul>
<hr>
-<div class="section" id="Invoking-Bash">
-<div class="header">
+<div class="section-level-extent" id="Invoking-Bash">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-Startup-Files" accesskey="n" rel="next">Bash Startup Files</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Invoking-Bash-1"></span><h3 class="section">6.1 Invoking Bash</h3>
+<h3 class="section" id="Invoking-Bash-1"><span>6.1 Invoking Bash<a class="copiable-link" href="#Invoking-Bash-1"> ¶</a></span></h3>
<div class="example">
-<pre class="example">bash [long-opt] [-ir] [-abefhkmnptuvxdBCDHP] [-o <var>option</var>]
- [-O <var>shopt_option</var>] [<var>argument</var> …]
-bash [long-opt] [-abefhkmnptuvxdBCDHP] [-o <var>option</var>]
- [-O <var>shopt_option</var>] -c <var>string</var> [<var>argument</var> …]
-bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o <var>option</var>]
- [-O <var>shopt_option</var>] [<var>argument</var> …]
+<pre class="example-preformatted">bash [long-opt] [-ir] [-abefhkmnptuvxdBCDHP] [-o <var class="var">option</var>]
+ [-O <var class="var">shopt_option</var>] [<var class="var">argument</var> ...]
+bash [long-opt] [-abefhkmnptuvxdBCDHP] [-o <var class="var">option</var>]
+ [-O <var class="var">shopt_option</var>] -c <var class="var">string</var> [<var class="var">argument</var> ...]
+bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o <var class="var">option</var>]
+ [-O <var class="var">shopt_option</var>] [<var class="var">argument</var> ...]
</pre></div>
-<p>All of the single-character options used with the <code>set</code> builtin
-(see <a href="#The-Set-Builtin">The Set Builtin</a>) can be used as options when the shell is invoked.
+<p>All of the single-character options used with the <code class="code">set</code> builtin
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>) can be used as options when the shell is invoked.
In addition, there are several multi-character
options that you can use. These options must appear on the command
line before the single-character options to be recognized.
</p>
-<dl compact="compact">
-<dt><span><code>--debugger</code></span></dt>
+<dl class="table">
+<dt><code class="code">--debugger</code></dt>
<dd><p>Arrange for the debugger profile to be executed before the shell
-starts. Turns on extended debugging mode (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>
-for a description of the <code>extdebug</code> option to the <code>shopt</code>
+starts. Turns on extended debugging mode (see <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>
+for a description of the <code class="code">extdebug</code> option to the <code class="code">shopt</code>
builtin).
</p>
</dd>
-<dt><span><code>--dump-po-strings</code></span></dt>
-<dd><p>A list of all double-quoted strings preceded by ‘<samp>$</samp>’
+<dt><code class="code">--dump-po-strings</code></dt>
+<dd><p>A list of all double-quoted strings preceded by ‘<samp class="samp">$</samp>’
is printed on the standard output
-in the <small>GNU</small> <code>gettext</code> PO (portable object) file format.
-Equivalent to <samp>-D</samp> except for the output format.
+in the <small class="sc">GNU</small> <code class="code">gettext</code> PO (portable object) file format.
+Equivalent to <samp class="option">-D</samp> except for the output format.
</p>
</dd>
-<dt><span><code>--dump-strings</code></span></dt>
-<dd><p>Equivalent to <samp>-D</samp>.
+<dt><code class="code">--dump-strings</code></dt>
+<dd><p>Equivalent to <samp class="option">-D</samp>.
</p>
</dd>
-<dt><span><code>--help</code></span></dt>
+<dt><code class="code">--help</code></dt>
<dd><p>Display a usage message on standard output and exit successfully.
</p>
</dd>
-<dt><span><code>--init-file <var>filename</var></code></span></dt>
-<dt><span><code>--rcfile <var>filename</var></code></span></dt>
-<dd><p>Execute commands from <var>filename</var> (instead of <samp>~/.bashrc</samp>)
+<dt><code class="code">--init-file <var class="var">filename</var></code></dt>
+<dt><code class="code">--rcfile <var class="var">filename</var></code></dt>
+<dd><p>Execute commands from <var class="var">filename</var> (instead of <samp class="file">~/.bashrc</samp>)
in an interactive shell.
</p>
</dd>
-<dt><span><code>--login</code></span></dt>
-<dd><p>Equivalent to <samp>-l</samp>.
+<dt><code class="code">--login</code></dt>
+<dd><p>Equivalent to <samp class="option">-l</samp>.
</p>
</dd>
-<dt><span><code>--noediting</code></span></dt>
-<dd><p>Do not use the <small>GNU</small> Readline library (see <a href="#Command-Line-Editing">Command Line Editing</a>)
+<dt><code class="code">--noediting</code></dt>
+<dd><p>Do not use the <small class="sc">GNU</small> Readline library (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>)
to read command lines when the shell is interactive.
</p>
</dd>
-<dt><span><code>--noprofile</code></span></dt>
-<dd><p>Don’t load the system-wide startup file <samp>/etc/profile</samp>
+<dt><code class="code">--noprofile</code></dt>
+<dd><p>Don’t load the system-wide startup file <samp class="file">/etc/profile</samp>
or any of the personal initialization files
-<samp>~/.bash_profile</samp>, <samp>~/.bash_login</samp>, or <samp>~/.profile</samp>
+<samp class="file">~/.bash_profile</samp>, <samp class="file">~/.bash_login</samp>, or <samp class="file">~/.profile</samp>
when Bash is invoked as a login shell.
</p>
</dd>
-<dt><span><code>--norc</code></span></dt>
-<dd><p>Don’t read the <samp>~/.bashrc</samp> initialization file in an
+<dt><code class="code">--norc</code></dt>
+<dd><p>Don’t read the <samp class="file">~/.bashrc</samp> initialization file in an
interactive shell. This is on by default if the shell is
-invoked as <code>sh</code>.
+invoked as <code class="code">sh</code>.
</p>
</dd>
-<dt><span><code>--posix</code></span></dt>
+<dt><code class="code">--posix</code></dt>
<dd><p>Change the behavior of Bash where the default operation differs
-from the <small>POSIX</small> standard to match the standard. This
+from the <small class="sc">POSIX</small> standard to match the standard. This
is intended to make Bash behave as a strict superset of that
-standard. See <a href="#Bash-POSIX-Mode">Bash and POSIX</a>, for a description of the Bash
-<small>POSIX</small> mode.
+standard. See <a class="xref" href="#Bash-POSIX-Mode">Bash and POSIX</a>, for a description of the Bash
+<small class="sc">POSIX</small> mode.
</p>
</dd>
-<dt><span><code>--restricted</code></span></dt>
-<dd><p>Equivalent to <samp>-r</samp>.
-Make the shell a restricted shell (see <a href="#The-Restricted-Shell">The Restricted Shell</a>).
+<dt><code class="code">--restricted</code></dt>
+<dd><p>Equivalent to <samp class="option">-r</samp>.
+Make the shell a restricted shell (see <a class="pxref" href="#The-Restricted-Shell">The Restricted Shell</a>).
</p>
</dd>
-<dt><span><code>--verbose</code></span></dt>
-<dd><p>Equivalent to <samp>-v</samp>. Print shell input lines as they’re read.
+<dt><code class="code">--verbose</code></dt>
+<dd><p>Equivalent to <samp class="option">-v</samp>. Print shell input lines as they’re read.
</p>
</dd>
-<dt><span><code>--version</code></span></dt>
+<dt><code class="code">--version</code></dt>
<dd><p>Show version information for this instance of
Bash on the standard output and exit successfully.
</p></dd>
</dl>
<p>There are several single-character options that may be supplied at
-invocation which are not available with the <code>set</code> builtin.
+invocation which are not available with the <code class="code">set</code> builtin.
</p>
-<dl compact="compact">
-<dt><span><code>-c</code></span></dt>
+<dl class="table">
+<dt><code class="code">-c</code></dt>
<dd><p>Read and execute commands from the first non-option argument
-<var>command_string</var>, then exit.
-If there are arguments after the <var>command_string</var>,
-the first argument is assigned to <code>$0</code>
+<var class="var">command_string</var>, then exit.
+If there are arguments after the <var class="var">command_string</var>,
+the first argument is assigned to <code class="code">$0</code>
and any remaining arguments are assigned to the positional parameters.
-The assignment to <code>$0</code> sets the name of the shell, which is used
+The assignment to <code class="code">$0</code> sets the name of the shell, which is used
in warning and error messages.
</p>
</dd>
-<dt><span><code>-i</code></span></dt>
+<dt><code class="code">-i</code></dt>
<dd><p>Force the shell to run interactively. Interactive shells are
-described in <a href="#Interactive-Shells">Interactive Shells</a>.
+described in <a class="ref" href="#Interactive-Shells">Interactive Shells</a>.
</p>
</dd>
-<dt><span><code>-l</code></span></dt>
+<dt><code class="code">-l</code></dt>
<dd><p>Make this shell act as if it had been directly invoked by login.
When the shell is interactive, this is equivalent to starting a
-login shell with ‘<samp>exec -l bash</samp>’.
+login shell with ‘<samp class="samp">exec -l bash</samp>’.
When the shell is not interactive, the login shell startup files will
be executed.
-‘<samp>exec bash -l</samp>’ or ‘<samp>exec bash --login</samp>’
+‘<samp class="samp">exec bash -l</samp>’ or ‘<samp class="samp">exec bash --login</samp>’
will replace the current shell with a Bash login shell.
-See <a href="#Bash-Startup-Files">Bash Startup Files</a>, for a description of the special behavior
+See <a class="xref" href="#Bash-Startup-Files">Bash Startup Files</a>, for a description of the special behavior
of a login shell.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
-<dd><p>Make the shell a restricted shell (see <a href="#The-Restricted-Shell">The Restricted Shell</a>).
+<dt><code class="code">-r</code></dt>
+<dd><p>Make the shell a restricted shell (see <a class="pxref" href="#The-Restricted-Shell">The Restricted Shell</a>).
</p>
</dd>
-<dt><span><code>-s</code></span></dt>
+<dt><code class="code">-s</code></dt>
<dd><p>If this option is present, or if no arguments remain after option
processing, then commands are read from the standard input.
This option allows the positional parameters to be set
through a pipe.
</p>
</dd>
-<dt><span><code>-D</code></span></dt>
-<dd><p>A list of all double-quoted strings preceded by ‘<samp>$</samp>’
+<dt><code class="code">-D</code></dt>
+<dd><p>A list of all double-quoted strings preceded by ‘<samp class="samp">$</samp>’
is printed on the standard output.
These are the strings that
are subject to language translation when the current locale
-is not <code>C</code> or <code>POSIX</code> (see <a href="#Locale-Translation">Locale-Specific Translation</a>).
-This implies the <samp>-n</samp> option; no commands will be executed.
-</p>
-</dd>
-<dt><span><code>[-+]O [<var>shopt_option</var>]</code></span></dt>
-<dd><p><var>shopt_option</var> is one of the shell options accepted by the
-<code>shopt</code> builtin (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
-If <var>shopt_option</var> is present, <samp>-O</samp> sets the value of that option;
-<samp>+O</samp> unsets it.
-If <var>shopt_option</var> is not supplied, the names and values of the shell
-options accepted by <code>shopt</code> are printed on the standard output.
-If the invocation option is <samp>+O</samp>, the output is displayed in a format
+is not <code class="code">C</code> or <code class="code">POSIX</code> (see <a class="pxref" href="#Locale-Translation">Locale-Specific Translation</a>).
+This implies the <samp class="option">-n</samp> option; no commands will be executed.
+</p>
+</dd>
+<dt><code class="code">[-+]O [<var class="var">shopt_option</var>]</code></dt>
+<dd><p><var class="var">shopt_option</var> is one of the shell options accepted by the
+<code class="code">shopt</code> builtin (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+If <var class="var">shopt_option</var> is present, <samp class="option">-O</samp> sets the value of that option;
+<samp class="option">+O</samp> unsets it.
+If <var class="var">shopt_option</var> is not supplied, the names and values of the shell
+options accepted by <code class="code">shopt</code> are printed on the standard output.
+If the invocation option is <samp class="option">+O</samp>, the output is displayed in a format
that may be reused as input.
</p>
</dd>
-<dt><span><code>--</code></span></dt>
-<dd><p>A <code>--</code> signals the end of options and disables further option
+<dt><code class="code">--</code></dt>
+<dd><p>A <code class="code">--</code> signals the end of options and disables further option
processing.
-Any arguments after the <code>--</code>
-are treated as a shell script filename (see <a href="#Shell-Scripts">Shell Scripts</a>)
+Any arguments after the <code class="code">--</code>
+are treated as a shell script filename (see <a class="pxref" href="#Shell-Scripts">Shell Scripts</a>)
and arguments passed to that script.
</p>
</dd>
-<dt><span><code>-</code></span></dt>
-<dd><p>Equivalent to <code>--</code>.
+<dt><code class="code">-</code></dt>
+<dd><p>Equivalent to <code class="code">--</code>.
</p>
</dd>
</dl>
-<span id="index-login-shell"></span>
-<p>A <em>login</em> shell is one whose first character of argument zero is
-‘<samp>-</samp>’, or one invoked with the <samp>--login</samp> option.
+<a class="index-entry-id" id="index-login-shell"></a>
+<p>A <em class="emph">login</em> shell is one whose first character of argument zero is
+‘<samp class="samp">-</samp>’, or one invoked with the <samp class="option">--login</samp> option.
</p>
-<span id="index-interactive-shell"></span>
-<p>An <em>interactive</em> shell is one started without non-option arguments,
-unless <samp>-s</samp> is specified,
-without specifying the <samp>-c</samp> option, and whose input and output are both
-connected to terminals (as determined by <code>isatty(3)</code>), or one
-started with the <samp>-i</samp> option. See <a href="#Interactive-Shells">Interactive Shells</a>, for more
+<a class="index-entry-id" id="index-interactive-shell"></a>
+<p>An <em class="emph">interactive</em> shell is one started without non-option arguments,
+unless <samp class="option">-s</samp> is specified,
+without specifying the <samp class="option">-c</samp> option, and whose input and output are both
+connected to terminals (as determined by <code class="code">isatty(3)</code>), or one
+started with the <samp class="option">-i</samp> option. See <a class="xref" href="#Interactive-Shells">Interactive Shells</a>, for more
information.
</p>
<p>If arguments remain after option processing, and neither the
-<samp>-c</samp> nor the <samp>-s</samp>
+<samp class="option">-c</samp> nor the <samp class="option">-s</samp>
option has been supplied, the first argument is assumed to
-be the name of a file containing shell commands (see <a href="#Shell-Scripts">Shell Scripts</a>).
-When Bash is invoked in this fashion, <code>$0</code>
+be the name of a file containing shell commands (see <a class="pxref" href="#Shell-Scripts">Shell Scripts</a>).
+When Bash is invoked in this fashion, <code class="code">$0</code>
is set to the name of the file, and the positional parameters
are set to the remaining arguments.
Bash reads and executes commands from this file, then exits.
</p>
<hr>
</div>
-<div class="section" id="Bash-Startup-Files">
-<div class="header">
+<div class="section-level-extent" id="Bash-Startup-Files">
+<div class="nav-panel">
<p>
Next: <a href="#Interactive-Shells" accesskey="n" rel="next">Interactive Shells</a>, Previous: <a href="#Invoking-Bash" accesskey="p" rel="prev">Invoking Bash</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-Startup-Files-1"></span><h3 class="section">6.2 Bash Startup Files</h3>
-<span id="index-startup-files"></span>
+<h3 class="section" id="Bash-Startup-Files-1"><span>6.2 Bash Startup Files<a class="copiable-link" href="#Bash-Startup-Files-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-startup-files"></a>
<p>This section describes how Bash executes its startup files.
If any of the files exist but cannot be read, Bash reports an error.
Tildes are expanded in filenames as described above under
-Tilde Expansion (see <a href="#Tilde-Expansion">Tilde Expansion</a>).
+Tilde Expansion (see <a class="pxref" href="#Tilde-Expansion">Tilde Expansion</a>).
</p>
-<p>Interactive shells are described in <a href="#Interactive-Shells">Interactive Shells</a>.
+<p>Interactive shells are described in <a class="ref" href="#Interactive-Shells">Interactive Shells</a>.
</p>
-<span id="Invoked-as-an-interactive-login-shell_002c-or-with-_002d_002dlogin"></span><h4 class="subsubheading">Invoked as an interactive login shell, or with <samp>--login</samp></h4>
+<h4 class="subsubheading" id="Invoked-as-an-interactive-login-shell_002c-or-with-_002d_002dlogin"><span>Invoked as an interactive login shell, or with <samp class="option">--login</samp><a class="copiable-link" href="#Invoked-as-an-interactive-login-shell_002c-or-with-_002d_002dlogin"> ¶</a></span></h4>
<p>When Bash is invoked as an interactive login shell, or as a
-non-interactive shell with the <samp>--login</samp> option, it first reads and
-executes commands from the file <samp>/etc/profile</samp>, if that file exists.
-After reading that file, it looks for <samp>~/.bash_profile</samp>,
-<samp>~/.bash_login</samp>, and <samp>~/.profile</samp>, in that order, and reads
+non-interactive shell with the <samp class="option">--login</samp> option, it first reads and
+executes commands from the file <samp class="file">/etc/profile</samp>, if that file exists.
+After reading that file, it looks for <samp class="file">~/.bash_profile</samp>,
+<samp class="file">~/.bash_login</samp>, and <samp class="file">~/.profile</samp>, in that order, and reads
and executes commands from the first one that exists and is readable.
-The <samp>--noprofile</samp> option may be used when the shell is started to
+The <samp class="option">--noprofile</samp> option may be used when the shell is started to
inhibit this behavior.
</p>
<p>When an interactive login shell exits,
-or a non-interactive login shell executes the <code>exit</code> builtin command,
+or a non-interactive login shell executes the <code class="code">exit</code> builtin command,
Bash reads and executes commands from
-the file <samp>~/.bash_logout</samp>, if it exists.
+the file <samp class="file">~/.bash_logout</samp>, if it exists.
</p>
-<span id="Invoked-as-an-interactive-non_002dlogin-shell"></span><h4 class="subsubheading">Invoked as an interactive non-login shell</h4>
+<h4 class="subsubheading" id="Invoked-as-an-interactive-non_002dlogin-shell"><span>Invoked as an interactive non-login shell<a class="copiable-link" href="#Invoked-as-an-interactive-non_002dlogin-shell"> ¶</a></span></h4>
<p>When an interactive shell that is not a login shell is started, Bash
-reads and executes commands from <samp>~/.bashrc</samp>, if that file exists.
-This may be inhibited by using the <samp>--norc</samp> option.
-The <samp>--rcfile <var>file</var></samp> option will force Bash to read and
-execute commands from <var>file</var> instead of <samp>~/.bashrc</samp>.
+reads and executes commands from <samp class="file">~/.bashrc</samp>, if that file exists.
+This may be inhibited by using the <samp class="option">--norc</samp> option.
+The <samp class="option">--rcfile <var class="var">file</var></samp> option will force Bash to read and
+execute commands from <var class="var">file</var> instead of <samp class="file">~/.bashrc</samp>.
</p>
-<p>So, typically, your <samp>~/.bash_profile</samp> contains the line
+<p>So, typically, your <samp class="file">~/.bash_profile</samp> contains the line
</p><div class="example">
-<pre class="example"><code>if [ -f ~/.bashrc ]; then . ~/.bashrc; fi</code>
+<pre class="example-preformatted"><code class="code">if [ -f ~/.bashrc ]; then . ~/.bashrc; fi</code>
</pre></div>
<p>after (or before) any login-specific initializations.
</p>
-<span id="Invoked-non_002dinteractively"></span><h4 class="subsubheading">Invoked non-interactively</h4>
+<h4 class="subsubheading" id="Invoked-non_002dinteractively"><span>Invoked non-interactively<a class="copiable-link" href="#Invoked-non_002dinteractively"> ¶</a></span></h4>
<p>When Bash is started non-interactively, to run a shell script,
-for example, it looks for the variable <code>BASH_ENV</code> in the environment,
+for example, it looks for the variable <code class="env">BASH_ENV</code> in the environment,
expands its value if it appears there, and uses the expanded value as
the name of a file to read and execute. Bash behaves as if the
following command were executed:
</p><div class="example">
-<pre class="example"><code>if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi</code>
+<pre class="example-preformatted"><code class="code">if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi</code>
</pre></div>
-<p>but the value of the <code>PATH</code> variable is not used to search for the
+<p>but the value of the <code class="env">PATH</code> variable is not used to search for the
filename.
</p>
<p>As noted above, if a non-interactive shell is invoked with the
-<samp>--login</samp> option, Bash attempts to read and execute commands from the
+<samp class="option">--login</samp> option, Bash attempts to read and execute commands from the
login shell startup files.
</p>
-<span id="Invoked-with-name-sh"></span><h4 class="subsubheading">Invoked with name <code>sh</code></h4>
+<h4 class="subsubheading" id="Invoked-with-name-sh"><span>Invoked with name <code class="code">sh</code><a class="copiable-link" href="#Invoked-with-name-sh"> ¶</a></span></h4>
-<p>If Bash is invoked with the name <code>sh</code>, it tries to mimic the
-startup behavior of historical versions of <code>sh</code> as closely as
-possible, while conforming to the <small>POSIX</small> standard as well.
+<p>If Bash is invoked with the name <code class="code">sh</code>, it tries to mimic the
+startup behavior of historical versions of <code class="code">sh</code> as closely as
+possible, while conforming to the <small class="sc">POSIX</small> standard as well.
</p>
<p>When invoked as an interactive login shell, or as a non-interactive
-shell with the <samp>--login</samp> option, it first attempts to read
-and execute commands from <samp>/etc/profile</samp> and <samp>~/.profile</samp>, in
+shell with the <samp class="option">--login</samp> option, it first attempts to read
+and execute commands from <samp class="file">/etc/profile</samp> and <samp class="file">~/.profile</samp>, in
that order.
-The <samp>--noprofile</samp> option may be used to inhibit this behavior.
-When invoked as an interactive shell with the name <code>sh</code>, Bash
-looks for the variable <code>ENV</code>, expands its value if it is defined,
+The <samp class="option">--noprofile</samp> option may be used to inhibit this behavior.
+When invoked as an interactive shell with the name <code class="code">sh</code>, Bash
+looks for the variable <code class="env">ENV</code>, expands its value if it is defined,
and uses the expanded value as the name of a file to read and execute.
-Since a shell invoked as <code>sh</code> does not attempt to read and execute
-commands from any other startup files, the <samp>--rcfile</samp> option has
+Since a shell invoked as <code class="code">sh</code> does not attempt to read and execute
+commands from any other startup files, the <samp class="option">--rcfile</samp> option has
no effect.
-A non-interactive shell invoked with the name <code>sh</code> does not attempt
+A non-interactive shell invoked with the name <code class="code">sh</code> does not attempt
to read any other startup files.
</p>
-<p>When invoked as <code>sh</code>, Bash enters <small>POSIX</small> mode after
+<p>When invoked as <code class="code">sh</code>, Bash enters <small class="sc">POSIX</small> mode after
the startup files are read.
</p>
-<span id="Invoked-in-POSIX-mode"></span><h4 class="subsubheading">Invoked in <small>POSIX</small> mode</h4>
+<h4 class="subsubheading" id="Invoked-in-posix-mode"><span>Invoked in <small class="sc">POSIX</small> mode<a class="copiable-link" href="#Invoked-in-posix-mode"> ¶</a></span></h4>
-<p>When Bash is started in <small>POSIX</small> mode, as with the
-<samp>--posix</samp> command line option, it follows the <small>POSIX</small> standard
+<p>When Bash is started in <small class="sc">POSIX</small> mode, as with the
+<samp class="option">--posix</samp> command line option, it follows the <small class="sc">POSIX</small> standard
for startup files.
-In this mode, interactive shells expand the <code>ENV</code> variable
+In this mode, interactive shells expand the <code class="env">ENV</code> variable
and commands are read and executed from the file whose name is the
expanded value.
No other startup files are read.
</p>
-<span id="Invoked-by-remote-shell-daemon"></span><h4 class="subsubheading">Invoked by remote shell daemon</h4>
+<h4 class="subsubheading" id="Invoked-by-remote-shell-daemon"><span>Invoked by remote shell daemon<a class="copiable-link" href="#Invoked-by-remote-shell-daemon"> ¶</a></span></h4>
<p>Bash attempts to determine when it is being run with its standard input
connected to a network connection, as when executed by
-the historical remote shell daemon, usually <code>rshd</code>,
-or the secure shell daemon <code>sshd</code>.
+the historical remote shell daemon, usually <code class="code">rshd</code>,
+or the secure shell daemon <code class="code">sshd</code>.
If Bash
determines it is being run non-interactively in this fashion,
-it reads and executes commands from <samp>~/.bashrc</samp>, if that
+it reads and executes commands from <samp class="file">~/.bashrc</samp>, if that
file exists and is readable.
-It will not do this if invoked as <code>sh</code>.
-The <samp>--norc</samp> option may be used to inhibit this behavior, and the
-<samp>--rcfile</samp> option may be used to force another file to be read, but
-neither <code>rshd</code> nor <code>sshd</code> generally invoke the shell with those
+It will not do this if invoked as <code class="code">sh</code>.
+The <samp class="option">--norc</samp> option may be used to inhibit this behavior, and the
+<samp class="option">--rcfile</samp> option may be used to force another file to be read, but
+neither <code class="code">rshd</code> nor <code class="code">sshd</code> generally invoke the shell with those
options or allow them to be specified.
</p>
-<span id="Invoked-with-unequal-effective-and-real-UID_002fGIDs"></span><h4 class="subsubheading">Invoked with unequal effective and real <small>UID/GID</small>s</h4>
+<h4 class="subsubheading" id="Invoked-with-unequal-effective-and-real-uid_002fgids"><span>Invoked with unequal effective and real <small class="sc">UID/GID</small>s<a class="copiable-link" href="#Invoked-with-unequal-effective-and-real-uid_002fgids"> ¶</a></span></h4>
<p>If Bash is started with the effective user (group) id not equal to the
-real user (group) id, and the <samp>-p</samp> option is not supplied, no startup
+real user (group) id, and the <samp class="option">-p</samp> option is not supplied, no startup
files are read, shell functions are not inherited from the environment,
-the <code>SHELLOPTS</code>, <code>BASHOPTS</code>, <code>CDPATH</code>, and <code>GLOBIGNORE</code>
+the <code class="env">SHELLOPTS</code>, <code class="env">BASHOPTS</code>, <code class="env">CDPATH</code>, and <code class="env">GLOBIGNORE</code>
variables, if they appear in the environment, are ignored, and the effective
user id is set to the real user id.
-If the <samp>-p</samp> option is supplied at invocation, the startup behavior is
+If the <samp class="option">-p</samp> option is supplied at invocation, the startup behavior is
the same, but the effective user id is not reset.
</p>
<hr>
</div>
-<div class="section" id="Interactive-Shells">
-<div class="header">
+<div class="section-level-extent" id="Interactive-Shells">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-Conditional-Expressions" accesskey="n" rel="next">Bash Conditional Expressions</a>, Previous: <a href="#Bash-Startup-Files" accesskey="p" rel="prev">Bash Startup Files</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Interactive-Shells-1"></span><h3 class="section">6.3 Interactive Shells</h3>
-<span id="index-interactive-shell-1"></span>
-<span id="index-shell_002c-interactive"></span>
+<h3 class="section" id="Interactive-Shells-1"><span>6.3 Interactive Shells<a class="copiable-link" href="#Interactive-Shells-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-interactive-shell-1"></a>
+<a class="index-entry-id" id="index-shell_002c-interactive"></a>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#What-is-an-Interactive-Shell_003f" accesskey="1">What is an Interactive Shell?</a></li>
<li><a href="#Is-this-Shell-Interactive_003f" accesskey="2">Is this Shell Interactive?</a></li>
<li><a href="#Interactive-Shell-Behavior" accesskey="3">Interactive Shell Behavior</a></li>
</ul>
<hr>
-<div class="subsection" id="What-is-an-Interactive-Shell_003f">
-<div class="header">
+<div class="subsection-level-extent" id="What-is-an-Interactive-Shell_003f">
+<div class="nav-panel">
<p>
Next: <a href="#Is-this-Shell-Interactive_003f" accesskey="n" rel="next">Is this Shell Interactive?</a>, Up: <a href="#Interactive-Shells" accesskey="u" rel="up">Interactive Shells</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="What-is-an-Interactive-Shell_003f-1"></span><h4 class="subsection">6.3.1 What is an Interactive Shell?</h4>
+<h4 class="subsection" id="What-is-an-Interactive-Shell_003f-1"><span>6.3.1 What is an Interactive Shell?<a class="copiable-link" href="#What-is-an-Interactive-Shell_003f-1"> ¶</a></span></h4>
<p>An interactive shell
is one started without non-option arguments
-(unless <samp>-s</samp> is specified)
-and without specifying the <samp>-c</samp> option,
+(unless <samp class="option">-s</samp> is specified)
+and without specifying the <samp class="option">-c</samp> option,
whose input and error output are both
-connected to terminals (as determined by <code>isatty(3)</code>),
-or one started with the <samp>-i</samp> option.
+connected to terminals (as determined by <code class="code">isatty(3)</code>),
+or one started with the <samp class="option">-i</samp> option.
</p>
<p>An interactive shell generally reads from and writes to a user’s
terminal.
</p>
-<p>The <samp>-s</samp> invocation option may be used to set the positional parameters
+<p>The <samp class="option">-s</samp> invocation option may be used to set the positional parameters
when an interactive shell is started.
</p>
<hr>
</div>
-<div class="subsection" id="Is-this-Shell-Interactive_003f">
-<div class="header">
+<div class="subsection-level-extent" id="Is-this-Shell-Interactive_003f">
+<div class="nav-panel">
<p>
Next: <a href="#Interactive-Shell-Behavior" accesskey="n" rel="next">Interactive Shell Behavior</a>, Previous: <a href="#What-is-an-Interactive-Shell_003f" accesskey="p" rel="prev">What is an Interactive Shell?</a>, Up: <a href="#Interactive-Shells" accesskey="u" rel="up">Interactive Shells</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Is-this-Shell-Interactive_003f-1"></span><h4 class="subsection">6.3.2 Is this Shell Interactive?</h4>
+<h4 class="subsection" id="Is-this-Shell-Interactive_003f-1"><span>6.3.2 Is this Shell Interactive?<a class="copiable-link" href="#Is-this-Shell-Interactive_003f-1"> ¶</a></span></h4>
<p>To determine within a startup script whether or not Bash is
running interactively,
-test the value of the ‘<samp>-</samp>’ special parameter.
-It contains <code>i</code> when the shell is interactive. For example:
+test the value of the ‘<samp class="samp">-</samp>’ special parameter.
+It contains <code class="code">i</code> when the shell is interactive. For example:
</p>
<div class="example">
-<pre class="example">case "$-" in
+<pre class="example-preformatted">case "$-" in
*i*) echo This shell is interactive ;;
*) echo This shell is not interactive ;;
esac
</pre></div>
<p>Alternatively, startup scripts may examine the variable
-<code>PS1</code>; it is unset in non-interactive shells, and set in
+<code class="env">PS1</code>; it is unset in non-interactive shells, and set in
interactive shells. Thus:
</p>
<div class="example">
-<pre class="example">if [ -z "$PS1" ]; then
+<pre class="example-preformatted">if [ -z "$PS1" ]; then
echo This shell is not interactive
else
echo This shell is interactive
<hr>
</div>
-<div class="subsection" id="Interactive-Shell-Behavior">
-<div class="header">
+<div class="subsection-level-extent" id="Interactive-Shell-Behavior">
+<div class="nav-panel">
<p>
Previous: <a href="#Is-this-Shell-Interactive_003f" accesskey="p" rel="prev">Is this Shell Interactive?</a>, Up: <a href="#Interactive-Shells" accesskey="u" rel="up">Interactive Shells</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Interactive-Shell-Behavior-1"></span><h4 class="subsection">6.3.3 Interactive Shell Behavior</h4>
+<h4 class="subsection" id="Interactive-Shell-Behavior-1"><span>6.3.3 Interactive Shell Behavior<a class="copiable-link" href="#Interactive-Shell-Behavior-1"> ¶</a></span></h4>
<p>When the shell is running interactively, it changes its behavior in
several ways.
</p>
-<ol>
-<li> Startup files are read and executed as described in <a href="#Bash-Startup-Files">Bash Startup Files</a>.
+<ol class="enumerate">
+<li> Startup files are read and executed as described in <a class="ref" href="#Bash-Startup-Files">Bash Startup Files</a>.
-</li><li> Job Control (see <a href="#Job-Control">Job Control</a>) is enabled by default. When job
+</li><li> Job Control (see <a class="pxref" href="#Job-Control">Job Control</a>) is enabled by default. When job
control is in effect, Bash ignores the keyboard-generated job control
-signals <code>SIGTTIN</code>, <code>SIGTTOU</code>, and <code>SIGTSTP</code>.
+signals <code class="code">SIGTTIN</code>, <code class="code">SIGTTOU</code>, and <code class="code">SIGTSTP</code>.
-</li><li> Bash expands and displays <code>PS1</code> before reading the first line
-of a command, and expands and displays <code>PS2</code> before reading the
+</li><li> Bash expands and displays <code class="env">PS1</code> before reading the first line
+of a command, and expands and displays <code class="env">PS2</code> before reading the
second and subsequent lines of a multi-line command.
-Bash expands and displays <code>PS0</code> after it reads a command but before
+Bash expands and displays <code class="env">PS0</code> after it reads a command but before
executing it.
-See <a href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt
+See <a class="ref" href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt
string escape sequences.
-</li><li> Bash executes the values of the set elements of the <code>PROMPT_COMMAND</code>
-array variable as commands before printing the primary prompt, <code>$PS1</code>
-(see <a href="#Bash-Variables">Bash Variables</a>).
+</li><li> Bash executes the values of the set elements of the <code class="env">PROMPT_COMMAND</code>
+array variable as commands before printing the primary prompt, <code class="env">$PS1</code>
+(see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
-</li><li> Readline (see <a href="#Command-Line-Editing">Command Line Editing</a>) is used to read commands from
+</li><li> Readline (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>) is used to read commands from
the user’s terminal.
-</li><li> Bash inspects the value of the <code>ignoreeof</code> option to <code>set -o</code>
-instead of exiting immediately when it receives an <code>EOF</code> on its
-standard input when reading a command (see <a href="#The-Set-Builtin">The Set Builtin</a>).
+</li><li> Bash inspects the value of the <code class="code">ignoreeof</code> option to <code class="code">set -o</code>
+instead of exiting immediately when it receives an <code class="code">EOF</code> on its
+standard input when reading a command (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
-</li><li> Command history (see <a href="#Bash-History-Facilities">Bash History Facilities</a>)
-and history expansion (see <a href="#History-Interaction">History Expansion</a>)
+</li><li> Command history (see <a class="pxref" href="#Bash-History-Facilities">Bash History Facilities</a>)
+and history expansion (see <a class="pxref" href="#History-Interaction">History Expansion</a>)
are enabled by default.
-Bash will save the command history to the file named by <code>$HISTFILE</code>
+Bash will save the command history to the file named by <code class="env">$HISTFILE</code>
when a shell with history enabled exits.
-</li><li> Alias expansion (see <a href="#Aliases">Aliases</a>) is performed by default.
+</li><li> Alias expansion (see <a class="pxref" href="#Aliases">Aliases</a>) is performed by default.
-</li><li> In the absence of any traps, Bash ignores <code>SIGTERM</code>
-(see <a href="#Signals">Signals</a>).
+</li><li> In the absence of any traps, Bash ignores <code class="code">SIGTERM</code>
+(see <a class="pxref" href="#Signals">Signals</a>).
-</li><li> In the absence of any traps, <code>SIGINT</code> is caught and handled
-(see <a href="#Signals">Signals</a>).
-<code>SIGINT</code> will interrupt some shell builtins.
+</li><li> In the absence of any traps, <code class="code">SIGINT</code> is caught and handled
+(see <a class="pxref" href="#Signals">Signals</a>).
+<code class="code">SIGINT</code> will interrupt some shell builtins.
-</li><li> An interactive login shell sends a <code>SIGHUP</code> to all jobs on exit
-if the <code>huponexit</code> shell option has been enabled (see <a href="#Signals">Signals</a>).
+</li><li> An interactive login shell sends a <code class="code">SIGHUP</code> to all jobs on exit
+if the <code class="code">huponexit</code> shell option has been enabled (see <a class="pxref" href="#Signals">Signals</a>).
-</li><li> The <samp>-n</samp> invocation option is ignored, and ‘<samp>set -n</samp>’ has
-no effect (see <a href="#The-Set-Builtin">The Set Builtin</a>).
+</li><li> The <samp class="option">-n</samp> invocation option is ignored, and ‘<samp class="samp">set -n</samp>’ has
+no effect (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
</li><li> Bash will check for mail periodically, depending on the values of the
-<code>MAIL</code>, <code>MAILPATH</code>, and <code>MAILCHECK</code> shell variables
-(see <a href="#Bash-Variables">Bash Variables</a>).
+<code class="env">MAIL</code>, <code class="env">MAILPATH</code>, and <code class="env">MAILCHECK</code> shell variables
+(see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
</li><li> Expansion errors due to references to unbound shell variables after
-‘<samp>set -u</samp>’ has been enabled will not cause the shell to exit
-(see <a href="#The-Set-Builtin">The Set Builtin</a>).
+‘<samp class="samp">set -u</samp>’ has been enabled will not cause the shell to exit
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
-</li><li> The shell will not exit on expansion errors caused by <var>var</var> being unset
-or null in <code>${<var>var</var>:?<var>word</var>}</code> expansions
-(see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li> The shell will not exit on expansion errors caused by <var class="var">var</var> being unset
+or null in <code class="code">${<var class="var">var</var>:?<var class="var">word</var>}</code> expansions
+(see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
</li><li> Redirection errors encountered by shell builtins will not cause the
shell to exit.
-</li><li> When running in <small>POSIX</small> mode, a special builtin returning an error
-status will not cause the shell to exit (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>).
+</li><li> When running in <small class="sc">POSIX</small> mode, a special builtin returning an error
+status will not cause the shell to exit (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>).
-</li><li> A failed <code>exec</code> will not cause the shell to exit
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+</li><li> A failed <code class="code">exec</code> will not cause the shell to exit
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
</li><li> Parser syntax errors will not cause the shell to exit.
-</li><li> If the <code>cdspell</code> shell option is enabled, the shell will attempt
-simple spelling correction for directory arguments to the <code>cd</code>
-builtin (see the description of the <code>cdspell</code>
-option to the <code>shopt</code> builtin in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
-The <code>cdspell</code> option is only effective in interactive shells.
+</li><li> If the <code class="code">cdspell</code> shell option is enabled, the shell will attempt
+simple spelling correction for directory arguments to the <code class="code">cd</code>
+builtin (see the description of the <code class="code">cdspell</code>
+option to the <code class="code">shopt</code> builtin in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+The <code class="code">cdspell</code> option is only effective in interactive shells.
-</li><li> The shell will check the value of the <code>TMOUT</code> variable and exit
+</li><li> The shell will check the value of the <code class="env">TMOUT</code> variable and exit
if a command is not read within the specified number of seconds after
-printing <code>$PS1</code> (see <a href="#Bash-Variables">Bash Variables</a>).
+printing <code class="env">$PS1</code> (see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
</li></ol>
<hr>
</div>
</div>
-<div class="section" id="Bash-Conditional-Expressions">
-<div class="header">
+<div class="section-level-extent" id="Bash-Conditional-Expressions">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Arithmetic" accesskey="n" rel="next">Shell Arithmetic</a>, Previous: <a href="#Interactive-Shells" accesskey="p" rel="prev">Interactive Shells</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-Conditional-Expressions-1"></span><h3 class="section">6.4 Bash Conditional Expressions</h3>
-<span id="index-expressions_002c-conditional"></span>
+<h3 class="section" id="Bash-Conditional-Expressions-1"><span>6.4 Bash Conditional Expressions<a class="copiable-link" href="#Bash-Conditional-Expressions-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-expressions_002c-conditional"></a>
-<p>Conditional expressions are used by the <code>[[</code> compound command
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>)
-and the <code>test</code> and <code>[</code> builtin commands
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-The <code>test</code>
-and <code>[</code> commands determine their behavior based on the number
+<p>Conditional expressions are used by the <code class="code">[[</code> compound command
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>)
+and the <code class="code">test</code> and <code class="code">[</code> builtin commands
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+The <code class="code">test</code>
+and <code class="code">[</code> commands determine their behavior based on the number
of arguments; see the descriptions of those commands for any other
command-specific actions.
</p>
If the operating system on which Bash is running provides these
special files, Bash will use them; otherwise it will emulate them
internally with this behavior:
-If the <var>file</var> argument to one of the primaries is of the form
-<samp>/dev/fd/<var>N</var></samp>, then file descriptor <var>N</var> is checked.
-If the <var>file</var> argument to one of the primaries is one of
-<samp>/dev/stdin</samp>, <samp>/dev/stdout</samp>, or <samp>/dev/stderr</samp>, file
+If the <var class="var">file</var> argument to one of the primaries is of the form
+<samp class="file">/dev/fd/<var class="var">N</var></samp>, then file descriptor <var class="var">N</var> is checked.
+If the <var class="var">file</var> argument to one of the primaries is one of
+<samp class="file">/dev/stdin</samp>, <samp class="file">/dev/stdout</samp>, or <samp class="file">/dev/stderr</samp>, file
descriptor 0, 1, or 2, respectively, is checked.
</p>
-<p>When used with <code>[[</code>, the ‘<samp><</samp>’ and ‘<samp>></samp>’ operators sort
+<p>When used with <code class="code">[[</code>, the ‘<samp class="samp"><</samp>’ and ‘<samp class="samp">></samp>’ operators sort
lexicographically using the current locale.
-The <code>test</code> command uses ASCII ordering.
+The <code class="code">test</code> command uses ASCII ordering.
</p>
<p>Unless otherwise specified, primaries that operate on files follow symbolic
links and operate on the target of the link, rather than the link itself.
</p>
-<dl compact="compact">
-<dt><span><code>-a <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists.
+<dl class="table">
+<dt><code class="code">-a <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists.
</p>
</dd>
-<dt><span><code>-b <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a block special file.
+<dt><code class="code">-b <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a block special file.
</p>
</dd>
-<dt><span><code>-c <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a character special file.
+<dt><code class="code">-c <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a character special file.
</p>
</dd>
-<dt><span><code>-d <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a directory.
+<dt><code class="code">-d <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a directory.
</p>
</dd>
-<dt><span><code>-e <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists.
+<dt><code class="code">-e <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists.
</p>
</dd>
-<dt><span><code>-f <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a regular file.
+<dt><code class="code">-f <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a regular file.
</p>
</dd>
-<dt><span><code>-g <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and its set-group-id bit is set.
+<dt><code class="code">-g <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and its set-group-id bit is set.
</p>
</dd>
-<dt><span><code>-h <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a symbolic link.
+<dt><code class="code">-h <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a symbolic link.
</p>
</dd>
-<dt><span><code>-k <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and its "sticky" bit is set.
+<dt><code class="code">-k <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and its "sticky" bit is set.
</p>
</dd>
-<dt><span><code>-p <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a named pipe (FIFO).
+<dt><code class="code">-p <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a named pipe (FIFO).
</p>
</dd>
-<dt><span><code>-r <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is readable.
+<dt><code class="code">-r <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is readable.
</p>
</dd>
-<dt><span><code>-s <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and has a size greater than zero.
+<dt><code class="code">-s <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and has a size greater than zero.
</p>
</dd>
-<dt><span><code>-t <var>fd</var></code></span></dt>
-<dd><p>True if file descriptor <var>fd</var> is open and refers to a terminal.
+<dt><code class="code">-t <var class="var">fd</var></code></dt>
+<dd><p>True if file descriptor <var class="var">fd</var> is open and refers to a terminal.
</p>
</dd>
-<dt><span><code>-u <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and its set-user-id bit is set.
+<dt><code class="code">-u <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and its set-user-id bit is set.
</p>
</dd>
-<dt><span><code>-w <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is writable.
+<dt><code class="code">-w <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is writable.
</p>
</dd>
-<dt><span><code>-x <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is executable.
+<dt><code class="code">-x <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is executable.
</p>
</dd>
-<dt><span><code>-G <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is owned by the effective group id.
+<dt><code class="code">-G <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is owned by the effective group id.
</p>
</dd>
-<dt><span><code>-L <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a symbolic link.
+<dt><code class="code">-L <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a symbolic link.
</p>
</dd>
-<dt><span><code>-N <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and has been modified since it was last read.
+<dt><code class="code">-N <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and has been modified since it was last read.
</p>
</dd>
-<dt><span><code>-O <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is owned by the effective user id.
+<dt><code class="code">-O <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is owned by the effective user id.
</p>
</dd>
-<dt><span><code>-S <var>file</var></code></span></dt>
-<dd><p>True if <var>file</var> exists and is a socket.
+<dt><code class="code">-S <var class="var">file</var></code></dt>
+<dd><p>True if <var class="var">file</var> exists and is a socket.
</p>
</dd>
-<dt><span><code><var>file1</var> -ef <var>file2</var></code></span></dt>
-<dd><p>True if <var>file1</var> and <var>file2</var> refer to the same device and
+<dt><code class="code"><var class="var">file1</var> -ef <var class="var">file2</var></code></dt>
+<dd><p>True if <var class="var">file1</var> and <var class="var">file2</var> refer to the same device and
inode numbers.
</p>
</dd>
-<dt><span><code><var>file1</var> -nt <var>file2</var></code></span></dt>
-<dd><p>True if <var>file1</var> is newer (according to modification date)
-than <var>file2</var>, or if <var>file1</var> exists and <var>file2</var> does not.
+<dt><code class="code"><var class="var">file1</var> -nt <var class="var">file2</var></code></dt>
+<dd><p>True if <var class="var">file1</var> is newer (according to modification date)
+than <var class="var">file2</var>, or if <var class="var">file1</var> exists and <var class="var">file2</var> does not.
</p>
</dd>
-<dt><span><code><var>file1</var> -ot <var>file2</var></code></span></dt>
-<dd><p>True if <var>file1</var> is older than <var>file2</var>,
-or if <var>file2</var> exists and <var>file1</var> does not.
+<dt><code class="code"><var class="var">file1</var> -ot <var class="var">file2</var></code></dt>
+<dd><p>True if <var class="var">file1</var> is older than <var class="var">file2</var>,
+or if <var class="var">file2</var> exists and <var class="var">file1</var> does not.
</p>
</dd>
-<dt><span><code>-o <var>optname</var></code></span></dt>
-<dd><p>True if the shell option <var>optname</var> is enabled.
-The list of options appears in the description of the <samp>-o</samp>
-option to the <code>set</code> builtin (see <a href="#The-Set-Builtin">The Set Builtin</a>).
+<dt><code class="code">-o <var class="var">optname</var></code></dt>
+<dd><p>True if the shell option <var class="var">optname</var> is enabled.
+The list of options appears in the description of the <samp class="option">-o</samp>
+option to the <code class="code">set</code> builtin (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
</p>
</dd>
-<dt><span><code>-v <var>varname</var></code></span></dt>
-<dd><p>True if the shell variable <var>varname</var> is set (has been assigned a value).
-If <var>varname</var> is an indexed
-array variable name subscripted by ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+<dt><code class="code">-v <var class="var">varname</var></code></dt>
+<dd><p>True if the shell variable <var class="var">varname</var> is set (has been assigned a value).
+If <var class="var">varname</var> is an indexed
+array variable name subscripted by ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
this returns true if the array has any set elements.
-If <var>varname</var> is an associative
-array variable name subscripted by ‘<samp>@</samp>’ or ‘<samp>*</samp>’,
+If <var class="var">varname</var> is an associative
+array variable name subscripted by ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’,
this returns true if an element with that key is set.
</p>
</dd>
-<dt><span><code>-R <var>varname</var></code></span></dt>
-<dd><p>True if the shell variable <var>varname</var> is set and is a name reference.
+<dt><code class="code">-R <var class="var">varname</var></code></dt>
+<dd><p>True if the shell variable <var class="var">varname</var> is set and is a name reference.
</p>
</dd>
-<dt><span><code>-z <var>string</var></code></span></dt>
-<dd><p>True if the length of <var>string</var> is zero.
+<dt><code class="code">-z <var class="var">string</var></code></dt>
+<dd><p>True if the length of <var class="var">string</var> is zero.
</p>
</dd>
-<dt><span><code>-n <var>string</var></code></span></dt>
-<dt><span><code><var>string</var></code></span></dt>
-<dd><p>True if the length of <var>string</var> is non-zero.
+<dt><code class="code">-n <var class="var">string</var></code></dt>
+<dt><code class="code"><var class="var">string</var></code></dt>
+<dd><p>True if the length of <var class="var">string</var> is non-zero.
</p>
</dd>
-<dt><span><code><var>string1</var> == <var>string2</var></code></span></dt>
-<dt><span><code><var>string1</var> = <var>string2</var></code></span></dt>
+<dt><code class="code"><var class="var">string1</var> == <var class="var">string2</var></code></dt>
+<dt><code class="code"><var class="var">string1</var> = <var class="var">string2</var></code></dt>
<dd><p>True if the strings are equal.
-When used with the <code>[[</code> command, this performs pattern matching as
-described above (see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+When used with the <code class="code">[[</code> command, this performs pattern matching as
+described above (see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
</p>
-<p>‘<samp>=</samp>’ should be used with the <code>test</code> command for <small>POSIX</small> conformance.
+<p>‘<samp class="samp">=</samp>’ should be used with the <code class="code">test</code> command for <small class="sc">POSIX</small> conformance.
</p>
</dd>
-<dt><span><code><var>string1</var> != <var>string2</var></code></span></dt>
+<dt><code class="code"><var class="var">string1</var> != <var class="var">string2</var></code></dt>
<dd><p>True if the strings are not equal.
</p>
</dd>
-<dt><span><code><var>string1</var> < <var>string2</var></code></span></dt>
-<dd><p>True if <var>string1</var> sorts before <var>string2</var> lexicographically.
+<dt><code class="code"><var class="var">string1</var> < <var class="var">string2</var></code></dt>
+<dd><p>True if <var class="var">string1</var> sorts before <var class="var">string2</var> lexicographically.
</p>
</dd>
-<dt><span><code><var>string1</var> > <var>string2</var></code></span></dt>
-<dd><p>True if <var>string1</var> sorts after <var>string2</var> lexicographically.
+<dt><code class="code"><var class="var">string1</var> > <var class="var">string2</var></code></dt>
+<dd><p>True if <var class="var">string1</var> sorts after <var class="var">string2</var> lexicographically.
</p>
</dd>
-<dt><span><code><var>arg1</var> OP <var>arg2</var></code></span></dt>
-<dd><p><code>OP</code> is one of
-‘<samp>-eq</samp>’, ‘<samp>-ne</samp>’, ‘<samp>-lt</samp>’, ‘<samp>-le</samp>’, ‘<samp>-gt</samp>’, or ‘<samp>-ge</samp>’.
-These arithmetic binary operators return true if <var>arg1</var>
+<dt><code class="code"><var class="var">arg1</var> OP <var class="var">arg2</var></code></dt>
+<dd><p><code class="code">OP</code> is one of
+‘<samp class="samp">-eq</samp>’, ‘<samp class="samp">-ne</samp>’, ‘<samp class="samp">-lt</samp>’, ‘<samp class="samp">-le</samp>’, ‘<samp class="samp">-gt</samp>’, or ‘<samp class="samp">-ge</samp>’.
+These arithmetic binary operators return true if <var class="var">arg1</var>
is equal to, not equal to, less than, less than or equal to,
-greater than, or greater than or equal to <var>arg2</var>,
-respectively. <var>Arg1</var> and <var>arg2</var>
+greater than, or greater than or equal to <var class="var">arg2</var>,
+respectively. <var class="var">Arg1</var> and <var class="var">arg2</var>
may be positive or negative integers.
-When used with the <code>[[</code> command, <var>Arg1</var> and <var>Arg2</var>
-are evaluated as arithmetic expressions (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>).
+When used with the <code class="code">[[</code> command, <var class="var">Arg1</var> and <var class="var">Arg2</var>
+are evaluated as arithmetic expressions (see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>).
</p></dd>
</dl>
<hr>
</div>
-<div class="section" id="Shell-Arithmetic">
-<div class="header">
+<div class="section-level-extent" id="Shell-Arithmetic">
+<div class="nav-panel">
<p>
Next: <a href="#Aliases" accesskey="n" rel="next">Aliases</a>, Previous: <a href="#Bash-Conditional-Expressions" accesskey="p" rel="prev">Bash Conditional Expressions</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Arithmetic-1"></span><h3 class="section">6.5 Shell Arithmetic</h3>
-<span id="index-arithmetic_002c-shell"></span>
-<span id="index-shell-arithmetic"></span>
-<span id="index-expressions_002c-arithmetic"></span>
-<span id="index-evaluation_002c-arithmetic"></span>
-<span id="index-arithmetic-evaluation"></span>
+<h3 class="section" id="Shell-Arithmetic-1"><span>6.5 Shell Arithmetic<a class="copiable-link" href="#Shell-Arithmetic-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-arithmetic_002c-shell"></a>
+<a class="index-entry-id" id="index-shell-arithmetic"></a>
+<a class="index-entry-id" id="index-expressions_002c-arithmetic"></a>
+<a class="index-entry-id" id="index-evaluation_002c-arithmetic"></a>
+<a class="index-entry-id" id="index-arithmetic-evaluation"></a>
<p>The shell allows arithmetic expressions to be evaluated, as one of
-the shell expansions or by using the <code>((</code> compound command, the
-<code>let</code> builtin, or the <samp>-i</samp> option to the <code>declare</code> builtin.
+the shell expansions or by using the <code class="code">((</code> compound command, the
+<code class="code">let</code> builtin, or the <samp class="option">-i</samp> option to the <code class="code">declare</code> builtin.
</p>
<p>Evaluation is done in fixed-width integers with no check for overflow,
though division by 0 is trapped and flagged as an error.
equal-precedence operators.
The levels are listed in order of decreasing precedence.
</p>
-<dl compact="compact">
-<dd><span id="index-arithmetic-operators"></span>
-<span id="index-unary-arithmetic-operators"></span>
-<span id="index-binary-arithmetic-operators"></span>
-<span id="index-conditional-arithmetic-operator"></span>
-<span id="index-bitwise-arithmetic-operators"></span>
+<dl class="table">
+<dd><a class="index-entry-id" id="index-arithmetic-operators"></a>
+<a class="index-entry-id" id="index-unary-arithmetic-operators"></a>
+<a class="index-entry-id" id="index-binary-arithmetic-operators"></a>
+<a class="index-entry-id" id="index-conditional-arithmetic-operator"></a>
+<a class="index-entry-id" id="index-bitwise-arithmetic-operators"></a>
</dd>
-<dt><span><code><var>id</var>++ <var>id</var>--</code></span></dt>
+<dt><code class="code"><var class="var">id</var>++ <var class="var">id</var>--</code></dt>
<dd><p>variable post-increment and post-decrement
</p>
</dd>
-<dt><span><code>++<var>id</var> --<var>id</var></code></span></dt>
+<dt><code class="code">++<var class="var">id</var> --<var class="var">id</var></code></dt>
<dd><p>variable pre-increment and pre-decrement
</p>
</dd>
-<dt><span><code>- +</code></span></dt>
+<dt><code class="code">- +</code></dt>
<dd><p>unary minus and plus
</p>
</dd>
-<dt><span><code>! ~</code></span></dt>
+<dt><code class="code">! ~</code></dt>
<dd><p>logical and bitwise negation
</p>
</dd>
-<dt><span><code>**</code></span></dt>
+<dt><code class="code">**</code></dt>
<dd><p>exponentiation
</p>
</dd>
-<dt><span><code>* / %</code></span></dt>
+<dt><code class="code">* / %</code></dt>
<dd><p>multiplication, division, remainder
</p>
</dd>
-<dt><span><code>+ -</code></span></dt>
+<dt><code class="code">+ -</code></dt>
<dd><p>addition, subtraction
</p>
</dd>
-<dt><span><code><< >></code></span></dt>
+<dt><code class="code"><< >></code></dt>
<dd><p>left and right bitwise shifts
</p>
</dd>
-<dt><span><code><= >= < ></code></span></dt>
+<dt><code class="code"><= >= < ></code></dt>
<dd><p>comparison
</p>
</dd>
-<dt><span><code>== !=</code></span></dt>
+<dt><code class="code">== !=</code></dt>
<dd><p>equality and inequality
</p>
</dd>
-<dt><span><code>&</code></span></dt>
+<dt><code class="code">&</code></dt>
<dd><p>bitwise AND
</p>
</dd>
-<dt><span><code>^</code></span></dt>
+<dt><code class="code">^</code></dt>
<dd><p>bitwise exclusive OR
</p>
</dd>
-<dt><span><code>|</code></span></dt>
+<dt><code class="code">|</code></dt>
<dd><p>bitwise OR
</p>
</dd>
-<dt><span><code>&&</code></span></dt>
+<dt><code class="code">&&</code></dt>
<dd><p>logical AND
</p>
</dd>
-<dt><span><code>||</code></span></dt>
+<dt><code class="code">||</code></dt>
<dd><p>logical OR
</p>
</dd>
-<dt><span><code>expr ? if-true-expr : if-false-expr</code></span></dt>
+<dt><code class="code">expr ? if-true-expr : if-false-expr</code></dt>
<dd><p>conditional operator
</p>
</dd>
-<dt><span><code>= *= /= %= += -= <<= >>= &= ^= |=</code></span></dt>
+<dt><code class="code">= *= /= %= += -= <<= >>= &= ^= |=</code></dt>
<dd><p>assignment
</p>
</dd>
-<dt><span><code>expr1 , expr2</code></span></dt>
+<dt><code class="code">expr1 , expr2</code></dt>
<dd><p>comma
</p></dd>
</dl>
by name without using the parameter expansion syntax.
The value of a variable is evaluated as an arithmetic expression
when it is referenced, or when a variable which has been given the
-<code>integer</code> attribute using ‘<samp>declare -i</samp>’ is assigned a value.
+<code class="code">integer</code> attribute using ‘<samp class="samp">declare -i</samp>’ is assigned a value.
A null value evaluates to 0.
-A shell variable need not have its <code>integer</code> attribute turned on
+A shell variable need not have its <code class="code">integer</code> attribute turned on
to be used in an expression.
</p>
<p>Integer constants follow the C language definition, without suffixes or
character constants.
Constants with a leading 0 are interpreted as octal numbers.
-A leading ‘<samp>0x</samp>’ or ‘<samp>0X</samp>’ denotes hexadecimal. Otherwise,
-numbers take the form [<var>base</var><code>#</code>]<var>n</var>, where the optional <var>base</var>
+A leading ‘<samp class="samp">0x</samp>’ or ‘<samp class="samp">0X</samp>’ denotes hexadecimal. Otherwise,
+numbers take the form [<var class="var">base</var><code class="code">#</code>]<var class="var">n</var>, where the optional <var class="var">base</var>
is a decimal number between 2 and 64 representing the arithmetic
-base, and <var>n</var> is a number in that base.
-If <var>base</var><code>#</code> is omitted, then base 10 is used.
-When specifying <var>n</var>,
+base, and <var class="var">n</var> is a number in that base.
+If <var class="var">base</var><code class="code">#</code> is omitted, then base 10 is used.
+When specifying <var class="var">n</var>,
if a non-digit is required,
the digits greater than 9 are represented by the lowercase letters,
-the uppercase letters, ‘<samp>@</samp>’, and ‘<samp>_</samp>’, in that order.
-If <var>base</var> is less than or equal to 36, lowercase and uppercase
+the uppercase letters, ‘<samp class="samp">@</samp>’, and ‘<samp class="samp">_</samp>’, in that order.
+If <var class="var">base</var> is less than or equal to 36, lowercase and uppercase
letters may be used interchangeably to represent numbers between 10
and 35.
</p>
</p>
<hr>
</div>
-<div class="section" id="Aliases">
-<div class="header">
+<div class="section-level-extent" id="Aliases">
+<div class="nav-panel">
<p>
Next: <a href="#Arrays" accesskey="n" rel="next">Arrays</a>, Previous: <a href="#Shell-Arithmetic" accesskey="p" rel="prev">Shell Arithmetic</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Aliases-1"></span><h3 class="section">6.6 Aliases</h3>
-<span id="index-alias-expansion"></span>
+<h3 class="section" id="Aliases-1"><span>6.6 Aliases<a class="copiable-link" href="#Aliases-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-alias-expansion"></a>
-<p><em>Aliases</em> allow a string to be substituted for a word that is in
+<p><em class="dfn">Aliases</em> allow a string to be substituted for a word that is in
a position in the input where it can be the first word of a simple
-command. Aliases have names and corresponding values that are set
-and unset using the <code>alias</code> and <code>unalias</code> builtin commands
-(see <a href="#Shell-Builtin-Commands">Shell Builtin Commands</a>).
+command.
+Aliases have names and corresponding values that are set
+and unset using the <code class="code">alias</code> and <code class="code">unalias</code> builtin commands
+(see <a class="pxref" href="#Shell-Builtin-Commands">Shell Builtin Commands</a>).
</p>
<p>If the shell reads an unquoted word in the right position, it checks
the word to see if it matches an alias name. If it matches, the shell
The shell doesn’t look at any characters following the word before
attempting alias substitution.
</p>
-<p>The characters ‘<samp>/</samp>’, ‘<samp>$</samp>’, ‘<samp>`</samp>’, ‘<samp>=</samp>’ and any of the
+<p>The characters ‘<samp class="samp">/</samp>’, ‘<samp class="samp">$</samp>’, ‘<samp class="samp">`</samp>’, ‘<samp class="samp">=</samp>’ and any of the
shell metacharacters or quoting characters listed above may not appear
in an alias name.
The replacement text may contain any valid
The first word of the replacement text is tested for
aliases, but a word that is identical to an alias being expanded
is not expanded a second time.
-This means that one may alias <code>ls</code> to <code>"ls -F"</code>,
+This means that one may alias <code class="code">ls</code> to <code class="code">"ls -F"</code>,
for instance, and Bash does not try to recursively expand the
replacement text.
</p>
<p>If the last character of the alias value is a
-<code>blank</code>, then the next command word following the
+<code class="code">blank</code>, then the next command word following the
alias is also checked for alias expansion.
</p>
-<p>Aliases are created and listed with the <code>alias</code>
-command, and removed with the <code>unalias</code> command.
+<p>Aliases are created and listed with the <code class="code">alias</code>
+command, and removed with the <code class="code">unalias</code> command.
</p>
<p>There is no mechanism for using arguments in the replacement text,
-as in <code>csh</code>.
+as in <code class="code">csh</code>.
If arguments are needed, use a shell function
-(see <a href="#Shell-Functions">Shell Functions</a>) instead.
+(see <a class="pxref" href="#Shell-Functions">Shell Functions</a>) instead.
</p>
<p>Aliases are not expanded when the shell is not interactive,
-unless the <code>expand_aliases</code> shell option is set using
-<code>shopt</code> (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+unless the <code class="code">expand_aliases</code> shell option is set using
+<code class="code">shopt</code> (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
</p>
<p>The rules concerning the definition and use of aliases are
somewhat confusing. Bash
is itself a command. As a consequence, aliases
defined in a function are not available until after that
function is executed. To be safe, always put
-alias definitions on a separate line, and do not use <code>alias</code>
+alias definitions on a separate line, and do not use <code class="code">alias</code>
in compound commands.
</p>
<p>For almost every purpose, shell functions are preferred over aliases.
</p>
<hr>
</div>
-<div class="section" id="Arrays">
-<div class="header">
+<div class="section-level-extent" id="Arrays">
+<div class="nav-panel">
<p>
Next: <a href="#The-Directory-Stack" accesskey="n" rel="next">The Directory Stack</a>, Previous: <a href="#Aliases" accesskey="p" rel="prev">Aliases</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Arrays-1"></span><h3 class="section">6.7 Arrays</h3>
-<span id="index-arrays"></span>
+<h3 class="section" id="Arrays-1"><span>6.7 Arrays<a class="copiable-link" href="#Arrays-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-arrays"></a>
<p>Bash provides one-dimensional indexed and associative array variables.
Any variable may be used as an indexed array;
-the <code>declare</code> builtin will explicitly declare an array.
+the <code class="code">declare</code> builtin will explicitly declare an array.
There is no maximum
limit on the size of an array, nor any requirement that members
be indexed or assigned contiguously.
Indexed arrays are referenced using integers (including arithmetic
-expressions (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>)) and are zero-based;
+expressions (see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>)) and are zero-based;
associative arrays use arbitrary strings.
Unless otherwise noted, indexed array indices must be non-negative integers.
</p>
<p>An indexed array is created automatically if any variable is assigned to
using the syntax
</p><div class="example">
-<pre class="example"><var>name</var>[<var>subscript</var>]=<var>value</var>
+<pre class="example-preformatted"><var class="var">name</var>[<var class="var">subscript</var>]=<var class="var">value</var>
</pre></div>
-<p>The <var>subscript</var>
+<p>The <var class="var">subscript</var>
is treated as an arithmetic expression that must evaluate to a number.
To explicitly declare an array, use
</p><div class="example">
-<pre class="example">declare -a <var>name</var>
+<pre class="example-preformatted">declare -a <var class="var">name</var>
</pre></div>
<p>The syntax
</p><div class="example">
-<pre class="example">declare -a <var>name</var>[<var>subscript</var>]
+<pre class="example-preformatted">declare -a <var class="var">name</var>[<var class="var">subscript</var>]
</pre></div>
-<p>is also accepted; the <var>subscript</var> is ignored.
+<p>is also accepted; the <var class="var">subscript</var> is ignored.
</p>
<p>Associative arrays are created using
</p><div class="example">
-<pre class="example">declare -A <var>name</var>
+<pre class="example-preformatted">declare -A <var class="var">name</var>
</pre></div>
<p>Attributes may be
-specified for an array variable using the <code>declare</code> and
-<code>readonly</code> builtins. Each attribute applies to all members of
+specified for an array variable using the <code class="code">declare</code> and
+<code class="code">readonly</code> builtins. Each attribute applies to all members of
an array.
</p>
<p>Arrays are assigned to using compound assignments of the form
</p><div class="example">
-<pre class="example"><var>name</var>=(<var>value1</var> <var>value2</var> … )
+<pre class="example-preformatted"><var class="var">name</var>=(<var class="var">value1</var> <var class="var">value2</var> ... )
</pre></div>
<p>where each
-<var>value</var> may be of the form <code>[<var>subscript</var>]=</code><var>string</var>.
-Indexed array assignments do not require anything but <var>string</var>.
+<var class="var">value</var> may be of the form <code class="code">[<var class="var">subscript</var>]=</code><var class="var">string</var>.
+Indexed array assignments do not require anything but <var class="var">string</var>.
When assigning to indexed arrays, if
the optional subscript is supplied, that index is assigned to;
otherwise the index of the element assigned is the last index assigned
to by the statement plus one. Indexing starts at zero.
</p>
-<p>Each <var>value</var> in the list undergoes the shell expansions
-described above (see <a href="#Shell-Expansions">Shell Expansions</a>),
-but <var>value</var>s that are valid variable assignments
+<p>Each <var class="var">value</var> in the list undergoes the shell expansions
+described above (see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>),
+but <var class="var">value</var>s that are valid variable assignments
including the brackets and subscript do not undergo
brace expansion and word splitting, as with individual
variable assignments.
may be either assignment statements, for which the subscript is required,
or a list of words that is interpreted as a sequence of alternating keys
and values:
-<var>name</var>=(<var>key1</var> <var>value1</var> <var>key2</var> <var>value2</var> … ).
+<var class="var">name</var>=(<var class="var">key1</var> <var class="var">value1</var> <var class="var">key2</var> <var class="var">value2</var> … ).
These are treated identically to
-<var>name</var>=( [<var>key1</var>]=<var>value1</var> [<var>key2</var>]=<var>value2</var> … ).
+<var class="var">name</var>=( [<var class="var">key1</var>]=<var class="var">value1</var> [<var class="var">key2</var>]=<var class="var">value2</var> … ).
The first word in the list determines how the remaining words
are interpreted; all assignments in a list must be of the same type.
When using key/value pairs, the keys may not be missing or empty;
a final missing value is treated like the empty string.
</p>
-<p>This syntax is also accepted by the <code>declare</code>
+<p>This syntax is also accepted by the <code class="code">declare</code>
builtin. Individual array elements may be assigned to using the
-<code><var>name</var>[<var>subscript</var>]=<var>value</var></code> syntax introduced above.
+<code class="code"><var class="var">name</var>[<var class="var">subscript</var>]=<var class="var">value</var></code> syntax introduced above.
</p>
-<p>When assigning to an indexed array, if <var>name</var>
+<p>When assigning to an indexed array, if <var class="var">name</var>
is subscripted by a negative number, that number is
interpreted as relative to one greater than the maximum index of
-<var>name</var>, so negative indices count back from the end of the
+<var class="var">name</var>, so negative indices count back from the end of the
array, and an index of -1 references the last element.
</p>
-<p>The ‘<samp>+=</samp>’ operator will append to an array variable when assigning
-using the compound assignment syntax; see <a href="#Shell-Parameters">Shell Parameters</a> above.
+<p>The ‘<samp class="samp">+=</samp>’ operator will append to an array variable when assigning
+using the compound assignment syntax; see <a class="ref" href="#Shell-Parameters">Shell Parameters</a> above.
</p>
<p>Any element of an array may be referenced using
-<code>${<var>name</var>[<var>subscript</var>]}</code>.
+<code class="code">${<var class="var">name</var>[<var class="var">subscript</var>]}</code>.
The braces are required to avoid
conflicts with the shell’s filename expansion operators. If the
-<var>subscript</var> is ‘<samp>@</samp>’ or ‘<samp>*</samp>’, the word expands to all members
-of the array <var>name</var>, unless otherwise noted in the description of a
+<var class="var">subscript</var> is ‘<samp class="samp">@</samp>’ or ‘<samp class="samp">*</samp>’, the word expands to all members
+of the array <var class="var">name</var>, unless otherwise noted in the description of a
builtin or word expansion.
These subscripts differ only when the word
appears within double quotes.
If the word is double-quoted,
-<code>${<var>name</var>[*]}</code> expands to a single word with
+<code class="code">${<var class="var">name</var>[*]}</code> expands to a single word with
the value of each array member separated by the first character of the
-<code>IFS</code> variable, and <code>${<var>name</var>[@]}</code> expands each element of
-<var>name</var> to a separate word. When there are no array members,
-<code>${<var>name</var>[@]}</code> expands to nothing.
+<code class="env">IFS</code> variable, and <code class="code">${<var class="var">name</var>[@]}</code> expands each element of
+<var class="var">name</var> to a separate word. When there are no array members,
+<code class="code">${<var class="var">name</var>[@]}</code> expands to nothing.
If the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the original
word, and the expansion of the last parameter is joined with the last
part of the original word.
This is analogous to the
-expansion of the special parameters ‘<samp>@</samp>’ and ‘<samp>*</samp>’.
-<code>${#<var>name</var>[<var>subscript</var>]}</code> expands to the length of
-<code>${<var>name</var>[<var>subscript</var>]}</code>.
-If <var>subscript</var> is ‘<samp>@</samp>’ or
-‘<samp>*</samp>’, the expansion is the number of elements in the array.
-If the <var>subscript</var>
+expansion of the special parameters ‘<samp class="samp">@</samp>’ and ‘<samp class="samp">*</samp>’.
+<code class="code">${#<var class="var">name</var>[<var class="var">subscript</var>]}</code> expands to the length of
+<code class="code">${<var class="var">name</var>[<var class="var">subscript</var>]}</code>.
+If <var class="var">subscript</var> is ‘<samp class="samp">@</samp>’ or
+‘<samp class="samp">*</samp>’, the expansion is the number of elements in the array.
+If the <var class="var">subscript</var>
used to reference an element of an indexed array
evaluates to a number less than zero, it is
interpreted as relative to one greater than the maximum index of the array,
value. The null string is a valid value.
</p>
<p>It is possible to obtain the keys (indices) of an array as well as the values.
-${!<var>name</var>[@]} and ${!<var>name</var>[*]} expand to the indices
-assigned in array variable <var>name</var>.
+${!<var class="var">name</var>[@]} and ${!<var class="var">name</var>[*]} expand to the indices
+assigned in array variable <var class="var">name</var>.
The treatment when in double quotes is similar to the expansion of the
-special parameters ‘<samp>@</samp>’ and ‘<samp>*</samp>’ within double quotes.
+special parameters ‘<samp class="samp">@</samp>’ and ‘<samp class="samp">*</samp>’ within double quotes.
</p>
-<p>The <code>unset</code> builtin is used to destroy arrays.
-<code>unset <var>name</var>[<var>subscript</var>]</code>
-destroys the array element at index <var>subscript</var>.
+<p>The <code class="code">unset</code> builtin is used to destroy arrays.
+<code class="code">unset <var class="var">name</var>[<var class="var">subscript</var>]</code>
+destroys the array element at index <var class="var">subscript</var>.
Negative subscripts to indexed arrays are interpreted as described above.
Unsetting the last element of an array variable does not unset the variable.
-<code>unset <var>name</var></code>, where <var>name</var> is an array, removes the
+<code class="code">unset <var class="var">name</var></code>, where <var class="var">name</var> is an array, removes the
entire array.
-<code>unset <var>name</var>[<var>subscript</var>]</code> behaves differently
+<code class="code">unset <var class="var">name</var>[<var class="var">subscript</var>]</code> behaves differently
depending on the array type when given a
-subscript of ‘<samp>*</samp>’ or ‘<samp>@</samp>’.
-When <var>name</var> is an associative array, it removes the element with key
-‘<samp>*</samp>’ or ‘<samp>@</samp>’.
-If <var>name</var> is an indexed array, <code>unset</code> removes all of the elements,
+subscript of ‘<samp class="samp">*</samp>’ or ‘<samp class="samp">@</samp>’.
+When <var class="var">name</var> is an associative array, it removes the element with key
+‘<samp class="samp">*</samp>’ or ‘<samp class="samp">@</samp>’.
+If <var class="var">name</var> is an indexed array, <code class="code">unset</code> removes all of the elements,
but does not remove the array itself.
</p>
<p>When using a variable name with a subscript as an argument to a command,
-such as with <code>unset</code>, without using the word expansion syntax
+such as with <code class="code">unset</code>, without using the word expansion syntax
described above, the argument is subject to the shell’s filename expansion.
If filename expansion is not desired, the argument should be quoted.
</p>
-<p>The <code>declare</code>, <code>local</code>, and <code>readonly</code>
-builtins each accept a <samp>-a</samp> option to specify an indexed
-array and a <samp>-A</samp> option to specify an associative array.
-If both options are supplied, <samp>-A</samp> takes precedence.
-The <code>read</code> builtin accepts a <samp>-a</samp>
+<p>The <code class="code">declare</code>, <code class="code">local</code>, and <code class="code">readonly</code>
+builtins each accept a <samp class="option">-a</samp> option to specify an indexed
+array and a <samp class="option">-A</samp> option to specify an associative array.
+If both options are supplied, <samp class="option">-A</samp> takes precedence.
+The <code class="code">read</code> builtin accepts a <samp class="option">-a</samp>
option to assign a list of words read from the standard input
to an array, and can read values from the standard input into
-individual array elements. The <code>set</code> and <code>declare</code>
+individual array elements. The <code class="code">set</code> and <code class="code">declare</code>
builtins display array values in a way that allows them to be
reused as input.
</p>
<hr>
</div>
-<div class="section" id="The-Directory-Stack">
-<div class="header">
+<div class="section-level-extent" id="The-Directory-Stack">
+<div class="nav-panel">
<p>
Next: <a href="#Controlling-the-Prompt" accesskey="n" rel="next">Controlling the Prompt</a>, Previous: <a href="#Arrays" accesskey="p" rel="prev">Arrays</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="The-Directory-Stack-1"></span><h3 class="section">6.8 The Directory Stack</h3>
-<span id="index-directory-stack"></span>
+<h3 class="section" id="The-Directory-Stack-1"><span>6.8 The Directory Stack<a class="copiable-link" href="#The-Directory-Stack-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-directory-stack"></a>
<p>The directory stack is a list of recently-visited directories. The
-<code>pushd</code> builtin adds directories to the stack as it changes
-the current directory, and the <code>popd</code> builtin removes specified
+<code class="code">pushd</code> builtin adds directories to the stack as it changes
+the current directory, and the <code class="code">popd</code> builtin removes specified
directories from the stack and changes the current directory to
-the directory removed. The <code>dirs</code> builtin displays the contents
+the directory removed. The <code class="code">dirs</code> builtin displays the contents
of the directory stack. The current directory is always the "top"
of the directory stack.
</p>
<p>The contents of the directory stack are also visible
-as the value of the <code>DIRSTACK</code> shell variable.
+as the value of the <code class="env">DIRSTACK</code> shell variable.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Directory-Stack-Builtins" accesskey="1">Directory Stack Builtins</a></li>
</ul>
<hr>
-<div class="subsection" id="Directory-Stack-Builtins">
-<div class="header">
+<div class="subsection-level-extent" id="Directory-Stack-Builtins">
+<div class="nav-panel">
<p>
Up: <a href="#The-Directory-Stack" accesskey="u" rel="up">The Directory Stack</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Directory-Stack-Builtins-1"></span><h4 class="subsection">6.8.1 Directory Stack Builtins</h4>
+<h4 class="subsection" id="Directory-Stack-Builtins-1"><span>6.8.1 Directory Stack Builtins<a class="copiable-link" href="#Directory-Stack-Builtins-1"> ¶</a></span></h4>
-<dl compact="compact">
-<dt id='index-dirs'><span><code>dirs</code><a href='#index-dirs' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-dirs"></a><span><code class="code">dirs</code><a class="copiable-link" href="#index-dirs"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">dirs [-clpv] [+<var>N</var> | -<var>N</var>]
+<pre class="example-preformatted">dirs [-clpv] [+<var class="var">N</var> | -<var class="var">N</var>]
</pre></div>
<p>Display the list of currently remembered directories. Directories
-are added to the list with the <code>pushd</code> command; the
-<code>popd</code> command removes directories from the list.
+are added to the list with the <code class="code">pushd</code> command; the
+<code class="code">popd</code> command removes directories from the list.
The current directory is always the first directory in the stack.
</p>
-<dl compact="compact">
-<dt><span><code>-c</code></span></dt>
+<dl class="table">
+<dt><code class="code">-c</code></dt>
<dd><p>Clears the directory stack by deleting all of the elements.
</p></dd>
-<dt><span><code>-l</code></span></dt>
+<dt><code class="code">-l</code></dt>
<dd><p>Produces a listing using full pathnames;
the default listing format uses a tilde to denote the home directory.
</p></dd>
-<dt><span><code>-p</code></span></dt>
-<dd><p>Causes <code>dirs</code> to print the directory stack with one entry per
+<dt><code class="code">-p</code></dt>
+<dd><p>Causes <code class="code">dirs</code> to print the directory stack with one entry per
line.
</p></dd>
-<dt><span><code>-v</code></span></dt>
-<dd><p>Causes <code>dirs</code> to print the directory stack with one entry per
+<dt><code class="code">-v</code></dt>
+<dd><p>Causes <code class="code">dirs</code> to print the directory stack with one entry per
line, prefixing each entry with its index in the stack.
</p></dd>
-<dt><span><code>+<var>N</var></code></span></dt>
-<dd><p>Displays the <var>N</var>th directory (counting from the left of the
-list printed by <code>dirs</code> when invoked without options), starting
+<dt><code class="code">+<var class="var">N</var></code></dt>
+<dd><p>Displays the <var class="var">N</var>th directory (counting from the left of the
+list printed by <code class="code">dirs</code> when invoked without options), starting
with zero.
</p></dd>
-<dt><span><code>-<var>N</var></code></span></dt>
-<dd><p>Displays the <var>N</var>th directory (counting from the right of the
-list printed by <code>dirs</code> when invoked without options), starting
+<dt><code class="code">-<var class="var">N</var></code></dt>
+<dd><p>Displays the <var class="var">N</var>th directory (counting from the right of the
+list printed by <code class="code">dirs</code> when invoked without options), starting
with zero.
</p></dd>
</dl>
</dd>
-<dt id='index-popd'><span><code>popd</code><a href='#index-popd' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-popd"></a><span><code class="code">popd</code><a class="copiable-link" href="#index-popd"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">popd [-n] [+<var>N</var> | -<var>N</var>]
+<pre class="example-preformatted">popd [-n] [+<var class="var">N</var> | -<var class="var">N</var>]
</pre></div>
<p>Removes elements from the directory stack.
The elements are numbered from 0 starting at the first directory
-listed by <code>dirs</code>;
-that is, <code>popd</code> is equivalent to <code>popd +0</code>.
+listed by <code class="code">dirs</code>;
+that is, <code class="code">popd</code> is equivalent to <code class="code">popd +0</code>.
</p>
-<p>When no arguments are given, <code>popd</code>
+<p>When no arguments are given, <code class="code">popd</code>
removes the top directory from the stack and changes to
the new top directory.
</p>
<p>Arguments, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-n</code></span></dt>
+<dl class="table">
+<dt><code class="code">-n</code></dt>
<dd><p>Suppresses the normal change of directory when removing directories
from the stack, so that only the stack is manipulated.
</p></dd>
-<dt><span><code>+<var>N</var></code></span></dt>
-<dd><p>Removes the <var>N</var>th directory (counting from the left of the
-list printed by <code>dirs</code>), starting with zero, from the stack.
+<dt><code class="code">+<var class="var">N</var></code></dt>
+<dd><p>Removes the <var class="var">N</var>th directory (counting from the left of the
+list printed by <code class="code">dirs</code>), starting with zero, from the stack.
</p></dd>
-<dt><span><code>-<var>N</var></code></span></dt>
-<dd><p>Removes the <var>N</var>th directory (counting from the right of the
-list printed by <code>dirs</code>), starting with zero, from the stack.
+<dt><code class="code">-<var class="var">N</var></code></dt>
+<dd><p>Removes the <var class="var">N</var>th directory (counting from the right of the
+list printed by <code class="code">dirs</code>), starting with zero, from the stack.
</p></dd>
</dl>
<p>If the top element of the directory stack is modified, and
-the <samp>-n</samp> option was not supplied, <code>popd</code> uses the <code>cd</code>
+the <samp class="option">-n</samp> option was not supplied, <code class="code">popd</code> uses the <code class="code">cd</code>
builtin to change to the directory at the top of the stack.
-If the <code>cd</code> fails, <code>popd</code> returns a non-zero value.
+If the <code class="code">cd</code> fails, <code class="code">popd</code> returns a non-zero value.
</p>
-<p>Otherwise, <code>popd</code> returns an unsuccessful status if
+<p>Otherwise, <code class="code">popd</code> returns an unsuccessful status if
an invalid option is encountered, the directory stack
is empty, or a non-existent directory stack entry is specified.
</p>
-<p>If the <code>popd</code> command is successful,
-Bash runs <code>dirs</code> to show the final contents of the directory stack,
+<p>If the <code class="code">popd</code> command is successful,
+Bash runs <code class="code">dirs</code> to show the final contents of the directory stack,
and the return status is 0.
</p>
-<span id="index-pushd"></span>
</dd>
-<dt><span><code>pushd</code></span></dt>
+<dt><a id="index-pushd"></a><span><code class="code">pushd</code><a class="copiable-link" href="#index-pushd"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">pushd [-n] [<var>+N</var> | <var>-N</var> | <var>dir</var>]
+<pre class="example-preformatted">pushd [-n] [<var class="var">+N</var> | <var class="var">-N</var> | <var class="var">dir</var>]
</pre></div>
<p>Adds a directory to the top of the directory stack, or rotates
the stack, making the new top of the stack the current working
directory.
-With no arguments, <code>pushd</code> exchanges the top two elements
+With no arguments, <code class="code">pushd</code> exchanges the top two elements
of the directory stack.
</p>
<p>Arguments, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-n</code></span></dt>
+<dl class="table">
+<dt><code class="code">-n</code></dt>
<dd><p>Suppresses the normal change of directory when rotating or
adding directories to the stack, so that only the stack is manipulated.
</p></dd>
-<dt><span><code>+<var>N</var></code></span></dt>
-<dd><p>Brings the <var>N</var>th directory (counting from the left of the
-list printed by <code>dirs</code>, starting with zero) to the top of
+<dt><code class="code">+<var class="var">N</var></code></dt>
+<dd><p>Brings the <var class="var">N</var>th directory (counting from the left of the
+list printed by <code class="code">dirs</code>, starting with zero) to the top of
the list by rotating the stack.
</p></dd>
-<dt><span><code>-<var>N</var></code></span></dt>
-<dd><p>Brings the <var>N</var>th directory (counting from the right of the
-list printed by <code>dirs</code>, starting with zero) to the top of
+<dt><code class="code">-<var class="var">N</var></code></dt>
+<dd><p>Brings the <var class="var">N</var>th directory (counting from the right of the
+list printed by <code class="code">dirs</code>, starting with zero) to the top of
the list by rotating the stack.
</p></dd>
-<dt><span><code><var>dir</var></code></span></dt>
-<dd><p>Makes <var>dir</var> be the top of the stack.
+<dt><code class="code"><var class="var">dir</var></code></dt>
+<dd><p>Makes <var class="var">dir</var> be the top of the stack.
</p></dd>
</dl>
-<p>After the stack has been modified, if the <samp>-n</samp> option was not
-supplied, <code>pushd</code> uses the <code>cd</code> builtin to change to the
+<p>After the stack has been modified, if the <samp class="option">-n</samp> option was not
+supplied, <code class="code">pushd</code> uses the <code class="code">cd</code> builtin to change to the
directory at the top of the stack.
-If the <code>cd</code> fails, <code>pushd</code> returns a non-zero value.
+If the <code class="code">cd</code> fails, <code class="code">pushd</code> returns a non-zero value.
</p>
-<p>Otherwise, if no arguments are supplied, <code>pushd</code> returns 0 unless the
+<p>Otherwise, if no arguments are supplied, <code class="code">pushd</code> returns 0 unless the
directory stack is empty.
-When rotating the directory stack, <code>pushd</code> returns 0 unless
+When rotating the directory stack, <code class="code">pushd</code> returns 0 unless
the directory stack is empty or a non-existent directory stack element
is specified.
</p>
-<p>If the <code>pushd</code> command is successful,
-Bash runs <code>dirs</code> to show the final contents of the directory stack.
+<p>If the <code class="code">pushd</code> command is successful,
+Bash runs <code class="code">dirs</code> to show the final contents of the directory stack.
</p>
</dd>
</dl>
<hr>
</div>
</div>
-<div class="section" id="Controlling-the-Prompt">
-<div class="header">
+<div class="section-level-extent" id="Controlling-the-Prompt">
+<div class="nav-panel">
<p>
Next: <a href="#The-Restricted-Shell" accesskey="n" rel="next">The Restricted Shell</a>, Previous: <a href="#The-Directory-Stack" accesskey="p" rel="prev">The Directory Stack</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Controlling-the-Prompt-1"></span><h3 class="section">6.9 Controlling the Prompt</h3>
-<span id="index-prompting"></span>
+<h3 class="section" id="Controlling-the-Prompt-1"><span>6.9 Controlling the Prompt<a class="copiable-link" href="#Controlling-the-Prompt-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-prompting"></a>
-<p>Bash examines the value of the array variable <code>PROMPT_COMMAND</code> just before
+<p>Bash examines the value of the array variable <code class="env">PROMPT_COMMAND</code> just before
printing each primary prompt.
-If any elements in <code>PROMPT_COMMAND</code> are set and non-null, Bash
+If any elements in <code class="env">PROMPT_COMMAND</code> are set and non-null, Bash
executes each value, in numeric order,
just as if it had been typed on the command line.
</p>
<p>In addition, the following table describes the special characters which
-can appear in the prompt variables <code>PS0</code>, <code>PS1</code>, <code>PS2</code>, and
-<code>PS4</code>:
+can appear in the prompt variables <code class="env">PS0</code>, <code class="env">PS1</code>, <code class="env">PS2</code>, and
+<code class="env">PS4</code>:
</p>
-<dl compact="compact">
-<dt><span><code>\a</code></span></dt>
+<dl class="table">
+<dt><code class="code">\a</code></dt>
<dd><p>A bell character.
</p></dd>
-<dt><span><code>\d</code></span></dt>
+<dt><code class="code">\d</code></dt>
<dd><p>The date, in "Weekday Month Date" format (e.g., "Tue May 26").
</p></dd>
-<dt><span><code>\D{<var>format</var>}</code></span></dt>
-<dd><p>The <var>format</var> is passed to <code>strftime</code>(3) and the result is inserted
-into the prompt string; an empty <var>format</var> results in a locale-specific
+<dt><code class="code">\D{<var class="var">format</var>}</code></dt>
+<dd><p>The <var class="var">format</var> is passed to <code class="code">strftime</code>(3) and the result is inserted
+into the prompt string; an empty <var class="var">format</var> results in a locale-specific
time representation. The braces are required.
</p></dd>
-<dt><span><code>\e</code></span></dt>
+<dt><code class="code">\e</code></dt>
<dd><p>An escape character.
</p></dd>
-<dt><span><code>\h</code></span></dt>
+<dt><code class="code">\h</code></dt>
<dd><p>The hostname, up to the first ‘.’.
</p></dd>
-<dt><span><code>\H</code></span></dt>
+<dt><code class="code">\H</code></dt>
<dd><p>The hostname.
</p></dd>
-<dt><span><code>\j</code></span></dt>
+<dt><code class="code">\j</code></dt>
<dd><p>The number of jobs currently managed by the shell.
</p></dd>
-<dt><span><code>\l</code></span></dt>
+<dt><code class="code">\l</code></dt>
<dd><p>The basename of the shell’s terminal device name.
</p></dd>
-<dt><span><code>\n</code></span></dt>
+<dt><code class="code">\n</code></dt>
<dd><p>A newline.
</p></dd>
-<dt><span><code>\r</code></span></dt>
+<dt><code class="code">\r</code></dt>
<dd><p>A carriage return.
</p></dd>
-<dt><span><code>\s</code></span></dt>
-<dd><p>The name of the shell, the basename of <code>$0</code> (the portion
+<dt><code class="code">\s</code></dt>
+<dd><p>The name of the shell, the basename of <code class="code">$0</code> (the portion
following the final slash).
</p></dd>
-<dt><span><code>\t</code></span></dt>
+<dt><code class="code">\t</code></dt>
<dd><p>The time, in 24-hour HH:MM:SS format.
</p></dd>
-<dt><span><code>\T</code></span></dt>
+<dt><code class="code">\T</code></dt>
<dd><p>The time, in 12-hour HH:MM:SS format.
</p></dd>
-<dt><span><code>\@</code></span></dt>
+<dt><code class="code">\@</code></dt>
<dd><p>The time, in 12-hour am/pm format.
</p></dd>
-<dt><span><code>\A</code></span></dt>
+<dt><code class="code">\A</code></dt>
<dd><p>The time, in 24-hour HH:MM format.
</p></dd>
-<dt><span><code>\u</code></span></dt>
+<dt><code class="code">\u</code></dt>
<dd><p>The username of the current user.
</p></dd>
-<dt><span><code>\v</code></span></dt>
+<dt><code class="code">\v</code></dt>
<dd><p>The version of Bash (e.g., 2.00)
</p></dd>
-<dt><span><code>\V</code></span></dt>
+<dt><code class="code">\V</code></dt>
<dd><p>The release of Bash, version + patchlevel (e.g., 2.00.0)
</p></dd>
-<dt><span><code>\w</code></span></dt>
-<dd><p>The value of the <code>PWD</code> shell variable (<code>$PWD</code>),
-with <code>$HOME</code> abbreviated with a tilde
-(uses the <code>$PROMPT_DIRTRIM</code> variable).
+<dt><code class="code">\w</code></dt>
+<dd><p>The value of the <code class="code">PWD</code> shell variable (<code class="env">$PWD</code>),
+with <code class="env">$HOME</code> abbreviated with a tilde
+(uses the <code class="env">$PROMPT_DIRTRIM</code> variable).
</p></dd>
-<dt><span><code>\W</code></span></dt>
-<dd><p>The basename of <code>$PWD</code>, with <code>$HOME</code> abbreviated with a tilde.
+<dt><code class="code">\W</code></dt>
+<dd><p>The basename of <code class="env">$PWD</code>, with <code class="env">$HOME</code> abbreviated with a tilde.
</p></dd>
-<dt><span><code>\!</code></span></dt>
+<dt><code class="code">\!</code></dt>
<dd><p>The history number of this command.
</p></dd>
-<dt><span><code>\#</code></span></dt>
+<dt><code class="code">\#</code></dt>
<dd><p>The command number of this command.
</p></dd>
-<dt><span><code>\$</code></span></dt>
-<dd><p>If the effective uid is 0, <code>#</code>, otherwise <code>$</code>.
+<dt><code class="code">\$</code></dt>
+<dd><p>If the effective uid is 0, <code class="code">#</code>, otherwise <code class="code">$</code>.
</p></dd>
-<dt><span><code>\<var>nnn</var></code></span></dt>
-<dd><p>The character whose ASCII code is the octal value <var>nnn</var>.
+<dt><code class="code">\<var class="var">nnn</var></code></dt>
+<dd><p>The character whose ASCII code is the octal value <var class="var">nnn</var>.
</p></dd>
-<dt><span><code>\\</code></span></dt>
+<dt><code class="code">\\</code></dt>
<dd><p>A backslash.
</p></dd>
-<dt><span><code>\[</code></span></dt>
+<dt><code class="code">\[</code></dt>
<dd><p>Begin a sequence of non-printing characters. This could be used to
embed a terminal control sequence into the prompt.
</p></dd>
-<dt><span><code>\]</code></span></dt>
+<dt><code class="code">\]</code></dt>
<dd><p>End a sequence of non-printing characters.
</p></dd>
</dl>
<p>The command number and the history number are usually different:
the history number of a command is its position in the history
list, which may include commands restored from the history file
-(see <a href="#Bash-History-Facilities">Bash History Facilities</a>), while the command number is
+(see <a class="pxref" href="#Bash-History-Facilities">Bash History Facilities</a>), while the command number is
the position in the sequence of commands executed during the current
shell session.
</p>
<p>After the string is decoded, it is expanded via
parameter expansion, command substitution, arithmetic
expansion, and quote removal, subject to the value of the
-<code>promptvars</code> shell option (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+<code class="code">promptvars</code> shell option (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
This can have unwanted side effects if escaped portions of the string
appear within command substitution or contain characters special to
word expansion.
</p>
<hr>
</div>
-<div class="section" id="The-Restricted-Shell">
-<div class="header">
+<div class="section-level-extent" id="The-Restricted-Shell">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-POSIX-Mode" accesskey="n" rel="next">Bash and POSIX</a>, Previous: <a href="#Controlling-the-Prompt" accesskey="p" rel="prev">Controlling the Prompt</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="The-Restricted-Shell-1"></span><h3 class="section">6.10 The Restricted Shell</h3>
-<span id="index-restricted-shell"></span>
+<h3 class="section" id="The-Restricted-Shell-1"><span>6.10 The Restricted Shell<a class="copiable-link" href="#The-Restricted-Shell-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-restricted-shell"></a>
-<p>If Bash is started with the name <code>rbash</code>, or the
-<samp>--restricted</samp>
+<p>If Bash is started with the name <code class="code">rbash</code>, or the
+<samp class="option">--restricted</samp>
or
-<samp>-r</samp>
+<samp class="option">-r</samp>
option is supplied at invocation, the shell becomes restricted.
A restricted shell is used to
set up an environment more controlled than the standard shell.
-A restricted shell behaves identically to <code>bash</code>
+A restricted shell behaves identically to <code class="code">bash</code>
with the exception that the following are disallowed or not performed:
</p>
-<ul>
-<li> Changing directories with the <code>cd</code> builtin.
-</li><li> Setting or unsetting the values of the <code>SHELL</code>, <code>PATH</code>,
-<code>HISTFILE</code>,
-<code>ENV</code>, or <code>BASH_ENV</code> variables.
-</li><li> Specifying command names containing slashes.
-</li><li> Specifying a filename containing a slash as an argument to the <code>.</code>
+<ul class="itemize mark-bullet">
+<li>Changing directories with the <code class="code">cd</code> builtin.
+</li><li>Setting or unsetting the values of the <code class="env">SHELL</code>, <code class="env">PATH</code>,
+<code class="env">HISTFILE</code>,
+<code class="env">ENV</code>, or <code class="env">BASH_ENV</code> variables.
+</li><li>Specifying command names containing slashes.
+</li><li>Specifying a filename containing a slash as an argument to the <code class="code">.</code>
builtin command.
-</li><li> Specifying a filename containing a slash as an argument to the <code>history</code>
+</li><li>Specifying a filename containing a slash as an argument to the <code class="code">history</code>
builtin command.
-</li><li> Specifying a filename containing a slash as an argument to the <samp>-p</samp>
-option to the <code>hash</code> builtin command.
-</li><li> Importing function definitions from the shell environment at startup.
-</li><li> Parsing the value of <code>SHELLOPTS</code> from the shell environment at startup.
-</li><li> Redirecting output using the ‘<samp>></samp>’, ‘<samp>>|</samp>’, ‘<samp><></samp>’, ‘<samp>>&</samp>’,
-‘<samp>&></samp>’, and ‘<samp>>></samp>’ redirection operators.
-</li><li> Using the <code>exec</code> builtin to replace the shell with another command.
-</li><li> Adding or deleting builtin commands with the
-<samp>-f</samp> and <samp>-d</samp> options to the <code>enable</code> builtin.
-</li><li> Using the <code>enable</code> builtin command to enable disabled shell builtins.
-</li><li> Specifying the <samp>-p</samp> option to the <code>command</code> builtin.
-</li><li> Turning off restricted mode with ‘<samp>set +r</samp>’ or ‘<samp>shopt -u restricted_shell</samp>’.
+</li><li>Specifying a filename containing a slash as an argument to the <samp class="option">-p</samp>
+option to the <code class="code">hash</code> builtin command.
+</li><li>Importing function definitions from the shell environment at startup.
+</li><li>Parsing the value of <code class="env">SHELLOPTS</code> from the shell environment at startup.
+</li><li>Redirecting output using the ‘<samp class="samp">></samp>’, ‘<samp class="samp">>|</samp>’, ‘<samp class="samp"><></samp>’, ‘<samp class="samp">>&</samp>’,
+‘<samp class="samp">&></samp>’, and ‘<samp class="samp">>></samp>’ redirection operators.
+</li><li>Using the <code class="code">exec</code> builtin to replace the shell with another command.
+</li><li>Adding or deleting builtin commands with the
+<samp class="option">-f</samp> and <samp class="option">-d</samp> options to the <code class="code">enable</code> builtin.
+</li><li>Using the <code class="code">enable</code> builtin command to enable disabled shell builtins.
+</li><li>Specifying the <samp class="option">-p</samp> option to the <code class="code">command</code> builtin.
+</li><li>Turning off restricted mode with ‘<samp class="samp">set +r</samp>’ or ‘<samp class="samp">shopt -u restricted_shell</samp>’.
</li></ul>
<p>These restrictions are enforced after any startup files are read.
</p>
<p>When a command that is found to be a shell script is executed
-(see <a href="#Shell-Scripts">Shell Scripts</a>), <code>rbash</code> turns off any restrictions in
+(see <a class="pxref" href="#Shell-Scripts">Shell Scripts</a>), <code class="code">rbash</code> turns off any restrictions in
the shell spawned to execute the script.
</p>
<p>The restricted shell mode is only one component of a useful restricted
-environment. It should be accompanied by setting <code>PATH</code> to a value
+environment. It should be accompanied by setting <code class="env">PATH</code> to a value
that allows execution of only a few verified commands (commands that
allow shell escapes are particularly vulnerable), changing the current
-directory to a non-writable directory other than <code>$HOME</code> after login,
+directory to a non-writable directory other than <code class="env">$HOME</code> after login,
not allowing the restricted shell to execute shell scripts, and cleaning
the environment of variables that cause some commands to modify their
-behavior (e.g., <code>VISUAL</code> or <code>PAGER</code>).
+behavior (e.g., <code class="env">VISUAL</code> or <code class="env">PAGER</code>).
</p>
<p>Modern systems provide more secure ways to implement a restricted environment,
-such as <code>jails</code>, <code>zones</code>, or <code>containers</code>.
+such as <code class="code">jails</code>, <code class="code">zones</code>, or <code class="code">containers</code>.
</p>
<hr>
</div>
-<div class="section" id="Bash-POSIX-Mode">
-<div class="header">
+<div class="section-level-extent" id="Bash-POSIX-Mode">
+<div class="nav-panel">
<p>
Next: <a href="#Shell-Compatibility-Mode" accesskey="n" rel="next">Shell Compatibility Mode</a>, Previous: <a href="#The-Restricted-Shell" accesskey="p" rel="prev">The Restricted Shell</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-and-POSIX"></span><h3 class="section">6.11 Bash and POSIX</h3>
+<h3 class="section" id="Bash-and-POSIX"><span>6.11 Bash and POSIX<a class="copiable-link" href="#Bash-and-POSIX"> ¶</a></span></h3>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#What-is-POSIX_003f" accesskey="1">What is POSIX?</a></li>
<li><a href="#Bash-POSIX-Mode-1" accesskey="2">Bash POSIX Mode</a></li>
</ul>
-<div class="subsection" id="What-is-POSIX_003f">
-<h4 class="subsection">6.11.1 What is POSIX?</h4>
-<span id="index-POSIX-description"></span>
+<div class="subsection-level-extent" id="What-is-POSIX_003f">
+<h4 class="subsection"><span>6.11.1 What is POSIX?<a class="copiable-link" href="#What-is-POSIX_003f"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-POSIX-description"></a>
-<p><small>POSIX</small> is the name for a family of standards based on Unix.
+<p><small class="sc">POSIX</small> is the name for a family of standards based on Unix.
A number of Unix services, tools, and functions are part of the standard,
ranging from the basic system calls and C library functions to common
applications and tools to system administration and management.
</p>
-<p>The <small>POSIX</small> Shell and Utilities standard was originally developed by
+<p>The <small class="sc">POSIX</small> Shell and Utilities standard was originally developed by
IEEE Working Group 1003.2 (POSIX.2).
The first edition of the 1003.2 standard was published in 1992.
It was merged with the original IEEE 1003.1 Working Group and is
IEEE, The Open Group and ISO/IEC SC22/WG15).
Today the Shell and Utilities are a volume within the set of documents that
make up IEEE Std 1003.1-2017, and thus the former POSIX.2 (from 1992)
-is now part of the current unified <small>POSIX</small> standard.
+is now part of the current unified <small class="sc">POSIX</small> standard.
</p>
<p>The Shell and Utilities volume concentrates on the command
interpreter interface and utility programs commonly executed from
the command line or by other programs.
The standard is freely available on the web at
-<a href="https://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html">https://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html</a>.
+<a class="url" href="https://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html">https://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html</a>.
</p>
<p>Bash is concerned with the aspects of the shell’s behavior defined
-by the <small>POSIX</small> Shell and Utilities volume. The shell command
+by the <small class="sc">POSIX</small> Shell and Utilities volume. The shell command
language has of course been standardized, including the basic flow
control and program execution constructs, I/O redirection and
pipelines, argument handling, variable expansion, and quoting.
</p>
-<p>The <i>special</i> builtins, which must be implemented as part of the
+<p>The <i class="i">special</i> builtins, which must be implemented as part of the
shell to provide the desired functionality, are specified as
-being part of the shell; examples of these are <code>eval</code> and
-<code>export</code>.
+being part of the shell; examples of these are <code class="code">eval</code> and
+<code class="code">export</code>.
Other utilities appear in the sections of POSIX not
devoted to the shell which are commonly (and in some cases must
be) implemented as builtin commands, such as
-<code>read</code> and <code>test</code>.
+<code class="code">read</code> and <code class="code">test</code>.
POSIX also specifies aspects of the shell’s interactive
behavior, including job control and command
line editing.
objections.
</p>
</div>
-<div class="subsection" id="Bash-POSIX-Mode-1">
-<h4 class="subsection">6.11.2 Bash POSIX Mode</h4>
-<span id="index-POSIX-Mode"></span>
+<div class="subsection-level-extent" id="Bash-POSIX-Mode-1">
+<h4 class="subsection"><span>6.11.2 Bash POSIX Mode<a class="copiable-link" href="#Bash-POSIX-Mode-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-POSIX-Mode"></a>
-<p>Although Bash is an implementation of the <small>POSIX</small> shell
+<p>Although Bash is an implementation of the <small class="sc">POSIX</small> shell
specification, there are areas where the Bash default behavior
differs from the specification.
-The Bash <em>posix mode</em> changes the Bash
+The Bash <em class="dfn">posix mode</em> changes the Bash
behavior in these areas so that it conforms to the standard more closely.
</p>
-<p>Starting Bash with the <samp>--posix</samp> command-line option or executing
-‘<samp>set -o posix</samp>’ while Bash is running will cause Bash to conform more
-closely to the <small>POSIX</small> standard by changing the behavior to
-match that specified by <small>POSIX</small> in areas where the Bash default differs.
+<p>Starting Bash with the <samp class="option">--posix</samp> command-line option or executing
+‘<samp class="samp">set -o posix</samp>’ while Bash is running will cause Bash to conform more
+closely to the <small class="sc">POSIX</small> standard by changing the behavior to
+match that specified by <small class="sc">POSIX</small> in areas where the Bash default differs.
</p>
-<p>When invoked as <code>sh</code>, Bash enters <small>POSIX</small> mode after reading the
+<p>When invoked as <code class="code">sh</code>, Bash enters <small class="sc">POSIX</small> mode after reading the
startup files.
</p>
-<p>The following list is what’s changed when ‘<small>POSIX</small> mode’ is in effect:
+<p>The following list is what’s changed when ‘<small class="sc">POSIX</small> mode’ is in effect:
</p>
-<ol>
-<li> Bash ensures that the <code>POSIXLY_CORRECT</code> variable is set.
+<ol class="enumerate">
+<li> Bash ensures that the <code class="env">POSIXLY_CORRECT</code> variable is set.
</li><li> When a command in the hash table no longer exists, Bash will re-search
-<code>$PATH</code> to find the new location. This is also available with
-‘<samp>shopt -s checkhash</samp>’.
+<code class="env">$PATH</code> to find the new location. This is also available with
+‘<samp class="samp">shopt -s checkhash</samp>’.
</li><li> Bash will not insert a command without the execute bit set into the
command hash table, even if it returns it as a (last-ditch) result
-from a <code>$PATH</code> search.
+from a <code class="env">$PATH</code> search.
</li><li> The message printed by the job control code and builtins when a job
exits with a non-zero status is ‘Done(status)’.
</li><li> The message printed by the job control code and builtins when a job
-is stopped is ‘Stopped(<var>signame</var>)’, where <var>signame</var> is, for
-example, <code>SIGTSTP</code>.
+is stopped is ‘Stopped(<var class="var">signame</var>)’, where <var class="var">signame</var> is, for
+example, <code class="code">SIGTSTP</code>.
</li><li> Alias expansion is always enabled, even in non-interactive shells.
expand aliases that are defined after the command substitution is initially
parsed (e.g., as part of a function definition).
-</li><li> The <small>POSIX</small> <code>PS1</code> and <code>PS2</code> expansions of ‘<samp>!</samp>’ to
-the history number and ‘<samp>!!</samp>’ to ‘<samp>!</samp>’ are enabled,
-and parameter expansion is performed on the values of <code>PS1</code> and
-<code>PS2</code> regardless of the setting of the <code>promptvars</code> option.
+</li><li> The <small class="sc">POSIX</small> <code class="env">PS1</code> and <code class="env">PS2</code> expansions of ‘<samp class="samp">!</samp>’ to
+the history number and ‘<samp class="samp">!!</samp>’ to ‘<samp class="samp">!</samp>’ are enabled,
+and parameter expansion is performed on the values of <code class="env">PS1</code> and
+<code class="env">PS2</code> regardless of the setting of the <code class="code">promptvars</code> option.
-</li><li> The <small>POSIX</small> startup files are executed (<code>$ENV</code>) rather than
+</li><li> The <small class="sc">POSIX</small> startup files are executed (<code class="env">$ENV</code>) rather than
the normal Bash files.
</li><li> Tilde expansion is only performed on assignments preceding a command
name, rather than on all assignment statements on the line.
-</li><li> The default history file is <samp>~/.sh_history</samp> (this is the
-default value the shell assigns to <code>$HISTFILE</code>).
+</li><li> The default history file is <samp class="file">~/.sh_history</samp> (this is the
+default value the shell assigns to <code class="env">$HISTFILE</code>).
</li><li> Redirection operators do not perform filename expansion on the word
in the redirection unless the shell is interactive.
</li><li> Redirection operators do not perform word splitting on the word in the
redirection.
-</li><li> Function names must be valid shell <code>name</code>s. That is, they may not
+</li><li> Function names must be valid shell <code class="code">name</code>s. That is, they may not
contain characters other than letters, digits, and underscores, and
may not start with a digit. Declaring a function with an invalid name
causes a fatal syntax error in non-interactive shells.
-</li><li> Function names may not be the same as one of the <small>POSIX</small> special
+</li><li> Function names may not be the same as one of the <small class="sc">POSIX</small> special
builtins.
</li><li> Even if a shell function whose name contains a slash was defined before
-entering <small>POSIX</small> mode, the shell will not execute a function whose name
+entering <small class="sc">POSIX</small> mode, the shell will not execute a function whose name
contains one or more slashes.
-</li><li> <small>POSIX</small> special builtins are found before shell functions
-during command lookup, including output printed by the <code>type</code>
-and <code>command</code> builtins.
+</li><li> <small class="sc">POSIX</small> special builtins are found before shell functions
+during command lookup, including output printed by the <code class="code">type</code>
+and <code class="code">command</code> builtins.
-</li><li> When printing shell function definitions (e.g., by <code>type</code>), Bash does
-not print the <code>function</code> keyword.
+</li><li> When printing shell function definitions (e.g., by <code class="code">type</code>), Bash does
+not print the <code class="code">function</code> keyword.
</li><li> Literal tildes that appear as the first character in elements of
-the <code>PATH</code> variable are not expanded as described above
-under <a href="#Tilde-Expansion">Tilde Expansion</a>.
+the <code class="env">PATH</code> variable are not expanded as described above
+under <a class="ref" href="#Tilde-Expansion">Tilde Expansion</a>.
-</li><li> The <code>time</code> reserved word may be used by itself as a command. When
+</li><li> The <code class="code">time</code> reserved word may be used by itself as a command. When
used in this way, it displays timing statistics for the shell and its
-completed children. The <code>TIMEFORMAT</code> variable controls the format
+completed children. The <code class="env">TIMEFORMAT</code> variable controls the format
of the timing information.
</li><li> When parsing and expanding a ${…} expansion that appears within
one of those defined to perform pattern removal. In this case, they do
not have to appear as matched pairs.
-</li><li> The parser does not recognize <code>time</code> as a reserved word if the next
-token begins with a ‘<samp>-</samp>’.
+</li><li> The parser does not recognize <code class="code">time</code> as a reserved word if the next
+token begins with a ‘<samp class="samp">-</samp>’.
-</li><li> The ‘<samp>!</samp>’ character does not introduce history expansion within a
-double-quoted string, even if the <code>histexpand</code> option is enabled.
+</li><li> The ‘<samp class="samp">!</samp>’ character does not introduce history expansion within a
+double-quoted string, even if the <code class="code">histexpand</code> option is enabled.
-</li><li> If a <small>POSIX</small> special builtin returns an error status, a
+</li><li> If a <small class="sc">POSIX</small> special builtin returns an error status, a
non-interactive shell exits. The fatal errors are those listed in
-the <small>POSIX</small> standard, and include things like passing incorrect options,
+the <small class="sc">POSIX</small> standard, and include things like passing incorrect options,
redirection errors, variable assignment errors for assignments preceding
the command name, and so on.
-</li><li> The <code>unset</code> builtin with the <samp>-v</samp> option specified returns a
-fatal error if it attempts to unset a <code>readonly</code> or <code>non-unsettable</code>
+</li><li> The <code class="code">unset</code> builtin with the <samp class="option">-v</samp> option specified returns a
+fatal error if it attempts to unset a <code class="code">readonly</code> or <code class="code">non-unsettable</code>
variable, or encounters a variable name argument that is an invalid identifier,
which causes a non-interactive shell to exit.
</li><li> When asked to unset a variable that appears in an assignment statement
-preceding the command, the <code>unset</code> builtin attempts to unset a variable
+preceding the command, the <code class="code">unset</code> builtin attempts to unset a variable
of the same name in the current or previous scope as well.
This implements the required "if an assigned variable is further modified
by the utility, the modifications made by the utility shall persist" behavior.
command in which the error occurred").
</li><li> A non-interactive shell exits with an error status if the iteration
-variable in a <code>for</code> statement or the selection variable in a
-<code>select</code> statement is a readonly variable or has an invalid name.
+variable in a <code class="code">for</code> statement or the selection variable in a
+<code class="code">select</code> statement is a readonly variable or has an invalid name.
-</li><li> Non-interactive shells exit if <var>filename</var> in <code>.</code> <var>filename</var>
+</li><li> Non-interactive shells exit if <var class="var">filename</var> in <code class="code">.</code> <var class="var">filename</var>
is not found.
</li><li> Non-interactive shells exit if a syntax error in an arithmetic expansion
</li><li> Non-interactive shells exit if a parameter expansion error occurs.
</li><li> Non-interactive shells exit if there is a syntax error in a script read
-with the <code>.</code> or <code>source</code> builtins, or in a string processed by
-the <code>eval</code> builtin.
+with the <code class="code">.</code> or <code class="code">source</code> builtins, or in a string processed by
+the <code class="code">eval</code> builtin.
</li><li> While variable indirection is available, it may not be applied to the
-‘<samp>#</samp>’ and ‘<samp>?</samp>’ special parameters.
+‘<samp class="samp">#</samp>’ and ‘<samp class="samp">?</samp>’ special parameters.
-</li><li> Expanding the ‘<samp>*</samp>’ special parameter in a pattern context where the
-expansion is double-quoted does not treat the <code>$*</code> as if it were
+</li><li> Expanding the ‘<samp class="samp">*</samp>’ special parameter in a pattern context where the
+expansion is double-quoted does not treat the <code class="code">$*</code> as if it were
double-quoted.
-</li><li> Assignment statements preceding <small>POSIX</small> special builtins
+</li><li> Assignment statements preceding <small class="sc">POSIX</small> special builtins
persist in the shell environment after the builtin completes.
-</li><li> The <code>command</code> builtin does not prevent builtins that take assignment
+</li><li> The <code class="code">command</code> builtin does not prevent builtins that take assignment
statements as arguments from expanding them as assignment statements;
-when not in <small>POSIX</small> mode, assignment builtins lose their assignment
-statement expansion properties when preceded by <code>command</code>.
+when not in <small class="sc">POSIX</small> mode, assignment builtins lose their assignment
+statement expansion properties when preceded by <code class="code">command</code>.
-</li><li> The <code>bg</code> builtin uses the required format to describe each job placed
+</li><li> The <code class="code">bg</code> builtin uses the required format to describe each job placed
in the background, which does not include an indication of whether the job
is the current or previous job.
-</li><li> The output of ‘<samp>kill -l</samp>’ prints all the signal names on a single line,
-separated by spaces, without the ‘<samp>SIG</samp>’ prefix.
+</li><li> The output of ‘<samp class="samp">kill -l</samp>’ prints all the signal names on a single line,
+separated by spaces, without the ‘<samp class="samp">SIG</samp>’ prefix.
-</li><li> The <code>kill</code> builtin does not accept signal names with a ‘<samp>SIG</samp>’
+</li><li> The <code class="code">kill</code> builtin does not accept signal names with a ‘<samp class="samp">SIG</samp>’
prefix.
-</li><li> The <code>export</code> and <code>readonly</code> builtin commands display their
-output in the format required by <small>POSIX</small>.
+</li><li> The <code class="code">export</code> and <code class="code">readonly</code> builtin commands display their
+output in the format required by <small class="sc">POSIX</small>.
-</li><li> The <code>trap</code> builtin displays signal names without the leading
-<code>SIG</code>.
+</li><li> If the <code class="code">export</code> and <code class="code">readonly</code> builtin commands get an argument
+that is not a valid identifier, and they are not operating on shell
+functions, they return an error.
+This will cause a non-interactive shell to exit because these are
+special builtins.
-</li><li> The <code>trap</code> builtin doesn’t check the first argument for a possible
+</li><li> The <code class="code">trap</code> builtin displays signal names without the leading
+<code class="code">SIG</code>.
+
+</li><li> The <code class="code">trap</code> builtin doesn’t check the first argument for a possible
signal specification and revert the signal handling to the original
disposition if it is, unless that argument consists solely of digits and
is a valid signal number. If users want to reset the handler for a given
-signal to the original disposition, they should use ‘<samp>-</samp>’ as the
+signal to the original disposition, they should use ‘<samp class="samp">-</samp>’ as the
first argument.
-</li><li> <code>trap -p</code> without arguments displays signals whose dispositions are
+</li><li> <code class="code">trap -p</code> without arguments displays signals whose dispositions are
set to SIG_DFL and those that were ignored when the shell started, not
just trapped signals.
-</li><li> The <code>.</code> and <code>source</code> builtins do not search the current directory
-for the filename argument if it is not found by searching <code>PATH</code>.
+</li><li> The <code class="code">.</code> and <code class="code">source</code> builtins do not search the current directory
+for the filename argument if it is not found by searching <code class="env">PATH</code>.
-</li><li> Enabling <small>POSIX</small> mode has the effect of setting the
-<code>inherit_errexit</code> option, so
+</li><li> Enabling <small class="sc">POSIX</small> mode has the effect of setting the
+<code class="code">inherit_errexit</code> option, so
subshells spawned to execute command substitutions inherit the value of
-the <samp>-e</samp> option from the parent shell.
-When the <code>inherit_errexit</code> option is not enabled,
-Bash clears the <samp>-e</samp> option in such subshells.
+the <samp class="option">-e</samp> option from the parent shell.
+When the <code class="code">inherit_errexit</code> option is not enabled,
+Bash clears the <samp class="option">-e</samp> option in such subshells.
-</li><li> Enabling <small>POSIX</small> mode has the effect of setting the
-<code>shift_verbose</code> option, so numeric arguments to <code>shift</code>
+</li><li> Enabling <small class="sc">POSIX</small> mode has the effect of setting the
+<code class="code">shift_verbose</code> option, so numeric arguments to <code class="code">shift</code>
that exceed the number of positional parameters will result in an
error message.
-</li><li> When the <code>alias</code> builtin displays alias definitions, it does not
-display them with a leading ‘<samp>alias </samp>’ unless the <samp>-p</samp> option
+</li><li> When the <code class="code">alias</code> builtin displays alias definitions, it does not
+display them with a leading ‘<samp class="samp">alias </samp>’ unless the <samp class="option">-p</samp> option
is supplied.
-</li><li> When the <code>set</code> builtin is invoked without options, it does not display
+</li><li> When the <code class="code">set</code> builtin is invoked without options, it does not display
shell function names and definitions.
-</li><li> When the <code>set</code> builtin is invoked without options, it displays
+</li><li> When the <code class="code">set</code> builtin is invoked without options, it displays
variable values without quotes, unless they contain shell metacharacters,
even if the result contains nonprinting characters.
-</li><li> When the <code>cd</code> builtin is invoked in logical mode, and the pathname
-constructed from <code>$PWD</code> and the directory name supplied as an argument
-does not refer to an existing directory, <code>cd</code> will fail instead of
+</li><li> When the <code class="code">cd</code> builtin is invoked in logical mode, and the pathname
+constructed from <code class="code">$PWD</code> and the directory name supplied as an argument
+does not refer to an existing directory, <code class="code">cd</code> will fail instead of
falling back to physical mode.
-</li><li> When the <code>cd</code> builtin cannot change a directory because the
+</li><li> When the <code class="code">cd</code> builtin cannot change a directory because the
length of the pathname
-constructed from <code>$PWD</code> and the directory name supplied as an argument
-exceeds <code>PATH_MAX</code> when all symbolic links are expanded, <code>cd</code> will
+constructed from <code class="code">$PWD</code> and the directory name supplied as an argument
+exceeds <code class="code">PATH_MAX</code> when all symbolic links are expanded, <code class="code">cd</code> will
fail instead of attempting to use only the supplied directory name.
-</li><li> The <code>pwd</code> builtin verifies that the value it prints is the same as the
+</li><li> The <code class="code">pwd</code> builtin verifies that the value it prints is the same as the
current directory, even if it is not asked to check the file system with the
-<samp>-P</samp> option.
+<samp class="option">-P</samp> option.
-</li><li> When listing the history, the <code>fc</code> builtin does not include an
+</li><li> When listing the history, the <code class="code">fc</code> builtin does not include an
indication of whether or not a history entry has been modified.
-</li><li> The default editor used by <code>fc</code> is <code>ed</code>.
+</li><li> The default editor used by <code class="code">fc</code> is <code class="code">ed</code>.
-</li><li> If there are too many arguments supplied to <code>fc -s</code>, <code>fc</code> prints
+</li><li> If there are too many arguments supplied to <code class="code">fc -s</code>, <code class="code">fc</code> prints
an error message and returns failure.
-</li><li> The <code>type</code> and <code>command</code> builtins will not report a non-executable
+</li><li> The <code class="code">type</code> and <code class="code">command</code> builtins will not report a non-executable
file as having been found, though the shell will attempt to execute such a
-file if it is the only so-named file found in <code>$PATH</code>.
+file if it is the only so-named file found in <code class="code">$PATH</code>.
-</li><li> The <code>vi</code> editing mode will invoke the <code>vi</code> editor directly when
-the ‘<samp>v</samp>’ command is run, instead of checking <code>$VISUAL</code> and
-<code>$EDITOR</code>.
+</li><li> The <code class="code">vi</code> editing mode will invoke the <code class="code">vi</code> editor directly when
+the ‘<samp class="samp">v</samp>’ command is run, instead of checking <code class="code">$VISUAL</code> and
+<code class="code">$EDITOR</code>.
-</li><li> When the <code>xpg_echo</code> option is enabled, Bash does not attempt to interpret
-any arguments to <code>echo</code> as options. Each argument is displayed, after
+</li><li> When the <code class="code">xpg_echo</code> option is enabled, Bash does not attempt to interpret
+any arguments to <code class="code">echo</code> as options. Each argument is displayed, after
escape characters are converted.
-</li><li> The <code>ulimit</code> builtin uses a block size of 512 bytes for the <samp>-c</samp>
-and <samp>-f</samp> options.
+</li><li> The <code class="code">ulimit</code> builtin uses a block size of 512 bytes for the <samp class="option">-c</samp>
+and <samp class="option">-f</samp> options.
-</li><li> The arrival of <code>SIGCHLD</code> when a trap is set on <code>SIGCHLD</code> does
-not interrupt the <code>wait</code> builtin and cause it to return immediately.
+</li><li> The arrival of <code class="code">SIGCHLD</code> when a trap is set on <code class="code">SIGCHLD</code> does
+not interrupt the <code class="code">wait</code> builtin and cause it to return immediately.
The trap command is run once for each child that exits.
-</li><li> The <code>read</code> builtin may be interrupted by a signal for which a trap
+</li><li> The <code class="code">read</code> builtin may be interrupted by a signal for which a trap
has been set.
-If Bash receives a trapped signal while executing <code>read</code>, the trap
-handler executes and <code>read</code> returns an exit status greater than 128.
+If Bash receives a trapped signal while executing <code class="code">read</code>, the trap
+handler executes and <code class="code">read</code> returns an exit status greater than 128.
-</li><li> The <code>printf</code> builtin uses <code>double</code> (via <code>strtod</code>) to convert
+</li><li> The <code class="code">printf</code> builtin uses <code class="code">double</code> (via <code class="code">strtod</code>) to convert
arguments corresponding to floating point conversion specifiers, instead of
-<code>long double</code> if it’s available. The ‘<samp>L</samp>’ length modifier forces
-<code>printf</code> to use <code>long double</code> if it’s available.
+<code class="code">long double</code> if it’s available. The ‘<samp class="samp">L</samp>’ length modifier forces
+<code class="code">printf</code> to use <code class="code">long double</code> if it’s available.
</li><li> Bash removes an exited background process’s status from the list of such
-statuses after the <code>wait</code> builtin is used to obtain it.
+statuses after the <code class="code">wait</code> builtin is used to obtain it.
-</li><li> A double quote character (‘<samp>"</samp>’) is treated specially when it appears
+</li><li> A double quote character (‘<samp class="samp">"</samp>’) is treated specially when it appears
in a backquoted command substitution in the body of a here-document that
undergoes expansion.
That means, for example, that a backslash preceding a double quote
character will escape it and the backslash will be removed.
-</li><li> The <code>test</code> builtin compares strings using the current locale when
-processing the ‘<samp><</samp>’ and ‘<samp>></samp>’ binary operators.
+</li><li> The <code class="code">test</code> builtin compares strings using the current locale when
+processing the ‘<samp class="samp"><</samp>’ and ‘<samp class="samp">></samp>’ binary operators.
-</li><li> The <code>test</code> builtin’s <samp>-t</samp> unary primary requires an argument.
-Historical versions of <code>test</code> made the argument optional in certain
+</li><li> The <code class="code">test</code> builtin’s <samp class="option">-t</samp> unary primary requires an argument.
+Historical versions of <code class="code">test</code> made the argument optional in certain
cases, and Bash attempts to accommodate those for backwards compatibility.
-</li><li> Command substitutions don’t set the ‘<samp>?</samp>’ special parameter. The exit
+</li><li> Command substitutions don’t set the ‘<samp class="samp">?</samp>’ special parameter. The exit
status of a simple command without a command word is still the exit status
of the last command substitution that occurred while evaluating the variable
assignments and redirections in that command, but that does not happen until
</li></ol>
-<p>There is other <small>POSIX</small> behavior that Bash does not implement by
-default even when in <small>POSIX</small> mode.
+<p>There is other <small class="sc">POSIX</small> behavior that Bash does not implement by
+default even when in <small class="sc">POSIX</small> mode.
Specifically:
</p>
-<ol>
-<li> The <code>fc</code> builtin checks <code>$EDITOR</code> as a program to edit history
-entries if <code>FCEDIT</code> is unset, rather than defaulting directly to
-<code>ed</code>. <code>fc</code> uses <code>ed</code> if <code>EDITOR</code> is unset.
+<ol class="enumerate">
+<li> The <code class="code">fc</code> builtin checks <code class="code">$EDITOR</code> as a program to edit history
+entries if <code class="code">FCEDIT</code> is unset, rather than defaulting directly to
+<code class="code">ed</code>. <code class="code">fc</code> uses <code class="code">ed</code> if <code class="code">EDITOR</code> is unset.
</li><li> A non-interactive shell does not exit if a variable assignment preceding
-the <code>command</code> builtin or another non-special builtin fails.
+the <code class="code">command</code> builtin or another non-special builtin fails.
-</li><li> As noted above, Bash requires the <code>xpg_echo</code> option to be enabled for
-the <code>echo</code> builtin to be fully conformant.
+</li><li> As noted above, Bash requires the <code class="code">xpg_echo</code> option to be enabled for
+the <code class="code">echo</code> builtin to be fully conformant.
</li></ol>
-<p>Bash can be configured to be <small>POSIX</small>-conformant by default, by specifying
-the <samp>--enable-strict-posix-default</samp> to <code>configure</code> when building
-(see <a href="#Optional-Features">Optional Features</a>).
+<p>Bash can be configured to be <small class="sc">POSIX</small>-conformant by default, by specifying
+the <samp class="option">--enable-strict-posix-default</samp> to <code class="code">configure</code> when building
+(see <a class="pxref" href="#Optional-Features">Optional Features</a>).
</p>
<hr>
</div>
</div>
-<div class="section" id="Shell-Compatibility-Mode">
-<div class="header">
+<div class="section-level-extent" id="Shell-Compatibility-Mode">
+<div class="nav-panel">
<p>
Previous: <a href="#Bash-POSIX-Mode" accesskey="p" rel="prev">Bash and POSIX</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Shell-Compatibility-Mode-1"></span><h3 class="section">6.12 Shell Compatibility Mode</h3>
-<span id="index-Compatibility-Level"></span>
-<span id="index-Compatibility-Mode"></span>
+<h3 class="section" id="Shell-Compatibility-Mode-1"><span>6.12 Shell Compatibility Mode<a class="copiable-link" href="#Shell-Compatibility-Mode-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-Compatibility-Level"></a>
+<a class="index-entry-id" id="index-Compatibility-Mode"></a>
-<p>Bash-4.0 introduced the concept of a <em>shell compatibility level</em>,
+<p>Bash-4.0 introduced the concept of a <em class="dfn">shell compatibility level</em>,
specified as a set of options to the shopt builtin
-(<code>compat31</code>,
-<code>compat32</code>,
-<code>compat40</code>,
-<code>compat41</code>,
+(<code class="code">compat31</code>,
+<code class="code">compat32</code>,
+<code class="code">compat40</code>,
+<code class="code">compat41</code>,
and so on).
There is only one current
compatibility level – each option is mutually exclusive.
behavior. It’s intended to be a temporary solution.
</p>
<p>This section does not mention behavior that is standard for a particular
-version (e.g., setting <code>compat32</code> means that quoting the rhs of the regexp
+version (e.g., setting <code class="code">compat32</code> means that quoting the rhs of the regexp
matching operator quotes special regexp characters in the word, which is
default behavior in bash-3.2 and subsequent versions).
</p>
-<p>If a user enables, say, <code>compat32</code>, it may affect the behavior of other
+<p>If a user enables, say, <code class="code">compat32</code>, it may affect the behavior of other
compatibility levels up to and including the current compatibility level.
The idea is that each compatibility level controls behavior that changed
in that version of Bash,
but that behavior may have been present in earlier versions.
-For instance, the change to use locale-based comparisons with the <code>[[</code>
+For instance, the change to use locale-based comparisons with the <code class="code">[[</code>
command came in bash-4.1, and earlier versions used ASCII-based comparisons,
-so enabling <code>compat32</code> will enable ASCII-based comparisons as well.
+so enabling <code class="code">compat32</code> will enable ASCII-based comparisons as well.
That granularity may not be sufficient for
all uses, and as a result users should employ compatibility levels carefully.
Read the documentation for a particular feature to find out the
current behavior.
</p>
-<p>Bash-4.3 introduced a new shell variable: <code>BASH_COMPAT</code>.
+<p>Bash-4.3 introduced a new shell variable: <code class="env">BASH_COMPAT</code>.
The value assigned
to this variable (a decimal version number like 4.2, or an integer
-corresponding to the <code>compat</code><var>NN</var> option, like 42) determines the
+corresponding to the <code class="code">compat</code><var class="var">NN</var> option, like 42) determines the
compatibility level.
</p>
<p>Starting with bash-4.4, Bash has begun deprecating older compatibility
levels.
-Eventually, the options will be removed in favor of <code>BASH_COMPAT</code>.
+Eventually, the options will be removed in favor of <code class="env">BASH_COMPAT</code>.
</p>
-<p>Bash-5.0 is the final version for which there will be an individual shopt
-option for the previous version. Users should use <code>BASH_COMPAT</code>
-on bash-5.0 and later versions.
+<p>Bash-5.0 was the final version for which there will be an individual shopt
+option for the previous version.
+Users should control the compatibility level with <code class="env">BASH_COMPAT</code>.
</p>
<p>The following table describes the behavior changes controlled by each
compatibility level setting.
-The <code>compat</code><var>NN</var> tag is used as shorthand for setting the
+The <code class="code">compat</code><var class="var">NN</var> tag is used as shorthand for setting the
compatibility level
-to <var>NN</var> using one of the following mechanisms.
+to <var class="var">NN</var> using one of the following mechanisms.
For versions prior to bash-5.0, the compatibility level may be set using
-the corresponding <code>compat</code><var>NN</var> shopt option.
-For bash-4.3 and later versions, the <code>BASH_COMPAT</code> variable is preferred,
+the corresponding <code class="code">compat</code><var class="var">NN</var> shopt option.
+For bash-4.3 and later versions, the <code class="env">BASH_COMPAT</code> variable is preferred,
and it is required for bash-5.1 and later versions.
</p>
-<dl compact="compact">
-<dt><span><code>compat31</code></span></dt>
-<dd><ul>
-<li> quoting the rhs of the <code>[[</code> command’s regexp matching operator (=~)
+<dl class="table">
+<dt><code class="code">compat31</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>quoting the rhs of the <code class="code">[[</code> command’s regexp matching operator (=~)
has no special effect
</li></ul>
</dd>
-<dt><span><code>compat40</code></span></dt>
-<dd><ul>
-<li> the ‘<samp><</samp>’ and ‘<samp>></samp>’ operators to the <code>[[</code> command do not
+<dt><code class="code">compat40</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>the ‘<samp class="samp"><</samp>’ and ‘<samp class="samp">></samp>’ operators to the <code class="code">[[</code> command do not
consider the current locale when comparing strings; they use ASCII
ordering.
Bash versions prior to bash-4.1 use ASCII collation and strcmp(3);
</li></ul>
</dd>
-<dt><span><code>compat41</code></span></dt>
-<dd><ul>
-<li> in posix mode, <code>time</code> may be followed by options and still be
-recognized as a reserved word (this is <small>POSIX</small> interpretation 267)
-</li><li> in posix mode, the parser requires that an even number of single
-quotes occur in the <var>word</var> portion of a double-quoted ${…}
+<dt><code class="code">compat41</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>in posix mode, <code class="code">time</code> may be followed by options and still be
+recognized as a reserved word (this is <small class="sc">POSIX</small> interpretation 267)
+</li><li>in posix mode, the parser requires that an even number of single
+quotes occur in the <var class="var">word</var> portion of a double-quoted ${…}
parameter expansion and treats them specially, so that characters within
the single quotes are considered quoted
-(this is <small>POSIX</small> interpretation 221)
+(this is <small class="sc">POSIX</small> interpretation 221)
</li></ul>
</dd>
-<dt><span><code>compat42</code></span></dt>
-<dd><ul>
-<li> the replacement string in double-quoted pattern substitution does not
+<dt><code class="code">compat42</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>the replacement string in double-quoted pattern substitution does not
undergo quote removal, as it does in versions after bash-4.2
-</li><li> in posix mode, single quotes are considered special when expanding
-the <var>word</var> portion of a double-quoted ${…} parameter expansion
+</li><li>in posix mode, single quotes are considered special when expanding
+the <var class="var">word</var> portion of a double-quoted ${…} parameter expansion
and can be used to quote a closing brace or other special character
-(this is part of <small>POSIX</small> interpretation 221);
+(this is part of <small class="sc">POSIX</small> interpretation 221);
in later versions, single quotes
are not special within double-quoted word expansions
</li></ul>
</dd>
-<dt><span><code>compat43</code></span></dt>
-<dd><ul>
-<li> the shell does not print a warning message if an attempt is made to
+<dt><code class="code">compat43</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>the shell does not print a warning message if an attempt is made to
use a quoted compound assignment as an argument to declare
(e.g., declare -a foo=’(1 2)’). Later versions warn that this usage is
deprecated
-</li><li> word expansion errors are considered non-fatal errors that cause the
+</li><li>word expansion errors are considered non-fatal errors that cause the
current command to fail, even in posix mode
(the default behavior is to make them fatal errors that cause the shell
to exit)
-</li><li> when executing a shell function, the loop state (while/until/etc.)
-is not reset, so <code>break</code> or <code>continue</code> in that function will break
+</li><li>when executing a shell function, the loop state (while/until/etc.)
+is not reset, so <code class="code">break</code> or <code class="code">continue</code> in that function will break
or continue loops in the calling context. Bash-4.4 and later reset
the loop state to prevent this
</li></ul>
</dd>
-<dt><span><code>compat44</code></span></dt>
-<dd><ul>
-<li> the shell sets up the values used by <code>BASH_ARGV</code> and <code>BASH_ARGC</code>
+<dt><code class="code">compat44</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>the shell sets up the values used by <code class="env">BASH_ARGV</code> and <code class="env">BASH_ARGC</code>
so they can expand to the shell’s positional parameters even if extended
debugging mode is not enabled
-</li><li> a subshell inherits loops from its parent context, so <code>break</code>
-or <code>continue</code> will cause the subshell to exit.
+</li><li>a subshell inherits loops from its parent context, so <code class="code">break</code>
+or <code class="code">continue</code> will cause the subshell to exit.
Bash-5.0 and later reset the loop state to prevent the exit
-</li><li> variable assignments preceding builtins like <code>export</code> and <code>readonly</code>
+</li><li>variable assignments preceding builtins like <code class="code">export</code> and <code class="code">readonly</code>
that set attributes continue to affect variables with the same
name in the calling environment even if the shell is not in posix
mode
</li></ul>
</dd>
-<dt><span><code>compat50 (set using BASH_COMPAT)</code></span></dt>
-<dd><ul>
-<li> Bash-5.1 changed the way <code>$RANDOM</code> is generated to introduce slightly
+<dt><code class="code">compat50 (set using BASH_COMPAT)</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>Bash-5.1 changed the way <code class="code">$RANDOM</code> is generated to introduce slightly
more randomness. If the shell compatibility level is set to 50 or
lower, it reverts to the method from bash-5.0 and previous versions,
so seeding the random number generator by assigning a value to
-<code>RANDOM</code> will produce the same sequence as in bash-5.0
-</li><li> If the command hash table is empty, Bash versions prior to bash-5.1
+<code class="env">RANDOM</code> will produce the same sequence as in bash-5.0
+</li><li>If the command hash table is empty, Bash versions prior to bash-5.1
printed an informational message to that effect, even when producing
output that can be reused as input. Bash-5.1 suppresses that message
-when the <samp>-l</samp> option is supplied.
+when the <samp class="option">-l</samp> option is supplied.
</li></ul>
</dd>
-<dt><span><code>compat51 (set using BASH_COMPAT)</code></span></dt>
-<dd><ul>
-<li> The <code>unset</code> builtin will unset the array <code>a</code> given an argument like
-‘<samp>a[@]</samp>’.
-Bash-5.2 will unset an element with key ‘<samp>@</samp>’ (associative arrays)
+<dt><code class="code">compat51 (set using BASH_COMPAT)</code></dt>
+<dd><ul class="itemize mark-bullet">
+<li>The <code class="code">unset</code> builtin will unset the array <code class="code">a</code> given an argument like
+‘<samp class="samp">a[@]</samp>’.
+Bash-5.2 will unset an element with key ‘<samp class="samp">@</samp>’ (associative arrays)
or remove all the elements without unsetting the array (indexed arrays)
-</li><li> arithmetic commands ( ((...)) ) and the expressions in an arithmetic for
+</li><li>arithmetic commands ( ((...)) ) and the expressions in an arithmetic for
statement can be expanded more than once
-</li><li> expressions used as arguments to arithmetic operators in the <code>[[</code>
+</li><li>expressions used as arguments to arithmetic operators in the <code class="code">[[</code>
conditional command can be expanded more than once
-</li><li> the expressions in substring parameter brace expansion can be
+</li><li>the expressions in substring parameter brace expansion can be
expanded more than once
-</li><li> the expressions in the $(( ... )) word expansion can be expanded
+</li><li>the expressions in the $(( ... )) word expansion can be expanded
more than once
-</li><li> arithmetic expressions used as indexed array subscripts can be
+</li><li>arithmetic expressions used as indexed array subscripts can be
expanded more than once
-</li><li> <code>test -v</code>, when given an argument of ‘<samp>A[@]</samp>’, where <var>A</var> is
+</li><li><code class="code">test -v</code>, when given an argument of ‘<samp class="samp">A[@]</samp>’, where <var class="var">A</var> is
an existing associative array, will return true if the array has any set
elements.
-Bash-5.2 will look for and report on a key named ‘<samp>@</samp>’
-</li><li> the ${<var>parameter</var>[:]=<var>value</var>} word expansion will return
-<var>value</var>, before any variable-specific transformations have been
+Bash-5.2 will look for and report on a key named ‘<samp class="samp">@</samp>’
+</li><li>the ${<var class="var">parameter</var>[:]=<var class="var">value</var>} word expansion will return
+<var class="var">value</var>, before any variable-specific transformations have been
performed (e.g., converting to lowercase).
Bash-5.2 will return the final value assigned to the variable.
-</li><li> Parsing command substitutions will behave as if extended globbing
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+</li><li>Parsing command substitutions will behave as if extended globbing
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
is enabled, so that parsing a command substitution containing an extglob
pattern (say, as part of a shell function) will not fail.
This assumes the intent is to enable extglob before the command is executed
<hr>
</div>
</div>
-<div class="chapter" id="Job-Control">
-<div class="header">
+<div class="chapter-level-extent" id="Job-Control">
+<div class="nav-panel">
<p>
Next: <a href="#Command-Line-Editing" accesskey="n" rel="next">Command Line Editing</a>, Previous: <a href="#Bash-Features" accesskey="p" rel="prev">Bash Features</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Job-Control-1"></span><h2 class="chapter">7 Job Control</h2>
+<h2 class="chapter" id="Job-Control-1"><span>7 Job Control<a class="copiable-link" href="#Job-Control-1"> ¶</a></span></h2>
<p>This chapter discusses what job control is, how it works, and how
Bash allows you to access its facilities.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Job-Control-Basics" accesskey="1">Job Control Basics</a></li>
<li><a href="#Job-Control-Builtins" accesskey="2">Job Control Builtins</a></li>
<li><a href="#Job-Control-Variables" accesskey="3">Job Control Variables</a></li>
</ul>
<hr>
-<div class="section" id="Job-Control-Basics">
-<div class="header">
+<div class="section-level-extent" id="Job-Control-Basics">
+<div class="nav-panel">
<p>
Next: <a href="#Job-Control-Builtins" accesskey="n" rel="next">Job Control Builtins</a>, Up: <a href="#Job-Control" accesskey="u" rel="up">Job Control</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Job-Control-Basics-1"></span><h3 class="section">7.1 Job Control Basics</h3>
-<span id="index-job-control-1"></span>
-<span id="index-foreground"></span>
-<span id="index-background"></span>
-<span id="index-suspending-jobs"></span>
+<h3 class="section" id="Job-Control-Basics-1"><span>7.1 Job Control Basics<a class="copiable-link" href="#Job-Control-Basics-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-job-control-1"></a>
+<a class="index-entry-id" id="index-foreground"></a>
+<a class="index-entry-id" id="index-background"></a>
+<a class="index-entry-id" id="index-suspending-jobs"></a>
<p>Job control
refers to the ability to selectively stop (suspend)
this facility via an interactive interface supplied jointly
by the operating system kernel’s terminal driver and Bash.
</p>
-<p>The shell associates a <var>job</var> with each pipeline. It keeps a
+<p>The shell associates a <var class="var">job</var> with each pipeline. It keeps a
table of currently executing jobs, which may be listed with the
-<code>jobs</code> command. When Bash starts a job
+<code class="code">jobs</code> command. When Bash starts a job
asynchronously, it prints a line that looks
like:
</p><div class="example">
-<pre class="example">[1] 25647
+<pre class="example-preformatted">[1] 25647
</pre></div>
-<p>indicating that this job is job number 1 and that the process <small>ID</small>
+<p>indicating that this job is job number 1 and that the process <small class="sc">ID</small>
of the last process in the pipeline associated with this job is
25647. All of the processes in a single pipeline are members of
-the same job. Bash uses the <var>job</var> abstraction as the
+the same job. Bash uses the <var class="var">job</var> abstraction as the
basis for job control.
</p>
<p>To facilitate the implementation of the user interface to job
control, the operating system maintains the notion of a current terminal
-process group <small>ID</small>. Members of this process group (processes whose
-process group <small>ID</small> is equal to the current terminal process group
-<small>ID</small>) receive keyboard-generated signals such as <code>SIGINT</code>.
+process group <small class="sc">ID</small>. Members of this process group (processes whose
+process group <small class="sc">ID</small> is equal to the current terminal process group
+<small class="sc">ID</small>) receive keyboard-generated signals such as <code class="code">SIGINT</code>.
These processes are said to be in the foreground. Background
-processes are those whose process group <small>ID</small> differs from the
+processes are those whose process group <small class="sc">ID</small> differs from the
terminal’s; such processes are immune to keyboard-generated
signals. Only foreground processes are allowed to read from or, if
-the user so specifies with <code>stty tostop</code>, write to the terminal.
+the user so specifies with <code class="code">stty tostop</code>, write to the terminal.
Background processes which attempt to
-read from (write to when <code>stty tostop</code> is in effect) the
-terminal are sent a <code>SIGTTIN</code> (<code>SIGTTOU</code>)
+read from (write to when <code class="code">tostop</code> is in effect) the
+terminal are sent a <code class="code">SIGTTIN</code> (<code class="code">SIGTTOU</code>)
signal by the kernel’s terminal driver,
which, unless caught, suspends the process.
</p>
<p>If the operating system on which Bash is running supports
job control, Bash contains facilities to use it. Typing the
-<em>suspend</em> character (typically ‘<samp>^Z</samp>’, Control-Z) while a
+<em class="dfn">suspend</em> character (typically ‘<samp class="samp">^Z</samp>’, Control-Z) while a
process is running causes that process to be stopped and returns
-control to Bash. Typing the <em>delayed suspend</em> character
-(typically ‘<samp>^Y</samp>’, Control-Y) causes the process to be stopped
+control to Bash. Typing the <em class="dfn">delayed suspend</em> character
+(typically ‘<samp class="samp">^Y</samp>’, Control-Y) causes the process to be stopped
when it attempts to read input from the terminal, and control to
be returned to Bash. The user then manipulates the state of
-this job, using the <code>bg</code> command to continue it in the
-background, the <code>fg</code> command to continue it in the
-foreground, or the <code>kill</code> command to kill it. A ‘<samp>^Z</samp>’
+this job, using the <code class="code">bg</code> command to continue it in the
+background, the <code class="code">fg</code> command to continue it in the
+foreground, or the <code class="code">kill</code> command to kill it. A ‘<samp class="samp">^Z</samp>’
takes effect immediately, and has the additional side effect of
causing pending output and typeahead to be discarded.
</p>
<p>There are a number of ways to refer to a job in the shell. The
-character ‘<samp>%</samp>’ introduces a job specification (<em>jobspec</em>).
+character ‘<samp class="samp">%</samp>’ introduces a job specification (<em class="dfn">jobspec</em>).
</p>
-<p>Job number <code>n</code> may be referred to as ‘<samp>%n</samp>’.
-The symbols ‘<samp>%%</samp>’ and ‘<samp>%+</samp>’ refer to the shell’s notion of the
+<p>Job number <code class="code">n</code> may be referred to as ‘<samp class="samp">%n</samp>’.
+The symbols ‘<samp class="samp">%%</samp>’ and ‘<samp class="samp">%+</samp>’ refer to the shell’s notion of the
current job, which is the last job stopped while it was in the foreground
or started in the background.
-A single ‘<samp>%</samp>’ (with no accompanying job specification) also refers
+A single ‘<samp class="samp">%</samp>’ (with no accompanying job specification) also refers
to the current job.
-The previous job may be referenced using ‘<samp>%-</samp>’.
-If there is only a single job, ‘<samp>%+</samp>’ and ‘<samp>%-</samp>’ can both be used
+The previous job may be referenced using ‘<samp class="samp">%-</samp>’.
+If there is only a single job, ‘<samp class="samp">%+</samp>’ and ‘<samp class="samp">%-</samp>’ can both be used
to refer to that job.
-In output pertaining to jobs (e.g., the output of the <code>jobs</code>
-command), the current job is always flagged with a ‘<samp>+</samp>’, and the
-previous job with a ‘<samp>-</samp>’.
+In output pertaining to jobs (e.g., the output of the <code class="code">jobs</code>
+command), the current job is always flagged with a ‘<samp class="samp">+</samp>’, and the
+previous job with a ‘<samp class="samp">-</samp>’.
</p>
<p>A job may also be referred to
using a prefix of the name used to start it, or using a substring
-that appears in its command line. For example, ‘<samp>%ce</samp>’ refers
-to a stopped job whose command name begins with ‘<samp>ce</samp>’.
-Using ‘<samp>%?ce</samp>’, on the
-other hand, refers to any job containing the string ‘<samp>ce</samp>’ in
+that appears in its command line. For example, ‘<samp class="samp">%ce</samp>’ refers
+to a stopped job whose command name begins with ‘<samp class="samp">ce</samp>’.
+Using ‘<samp class="samp">%?ce</samp>’, on the
+other hand, refers to any job containing the string ‘<samp class="samp">ce</samp>’ in
its command line. If the prefix or substring matches more than one job,
Bash reports an error.
</p>
<p>Simply naming a job can be used to bring it into the foreground:
-‘<samp>%1</samp>’ is a synonym for ‘<samp>fg %1</samp>’, bringing job 1 from the
-background into the foreground. Similarly, ‘<samp>%1 &</samp>’ resumes
-job 1 in the background, equivalent to ‘<samp>bg %1</samp>’
+‘<samp class="samp">%1</samp>’ is a synonym for ‘<samp class="samp">fg %1</samp>’, bringing job 1 from the
+background into the foreground. Similarly, ‘<samp class="samp">%1 &</samp>’ resumes
+job 1 in the background, equivalent to ‘<samp class="samp">bg %1</samp>’
</p>
<p>The shell learns immediately whenever a job changes state.
Normally, Bash waits until it is about to print a prompt
before reporting changes in a job’s status so as to not interrupt
any other output.
-If the <samp>-b</samp> option to the <code>set</code> builtin is enabled,
-Bash reports such changes immediately (see <a href="#The-Set-Builtin">The Set Builtin</a>).
-Any trap on <code>SIGCHLD</code> is executed for each child process
+If the <samp class="option">-b</samp> option to the <code class="code">set</code> builtin is enabled,
+Bash reports such changes immediately (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
+Any trap on <code class="code">SIGCHLD</code> is executed for each child process
that exits.
</p>
<p>If an attempt to exit Bash is made while jobs are stopped, (or running, if
-the <code>checkjobs</code> option is enabled – see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), the
-shell prints a warning message, and if the <code>checkjobs</code> option is
+the <code class="code">checkjobs</code> option is enabled – see <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>), the
+shell prints a warning message, and if the <code class="code">checkjobs</code> option is
enabled, lists the jobs and their statuses.
-The <code>jobs</code> command may then be used to inspect their status.
+The <code class="code">jobs</code> command may then be used to inspect their status.
If a second attempt to exit is made without an intervening command,
Bash does not print another warning, and any stopped jobs are terminated.
</p>
-<p>When the shell is waiting for a job or process using the <code>wait</code>
-builtin, and job control is enabled, <code>wait</code> will return when the
-job changes state. The <samp>-f</samp> option causes <code>wait</code> to wait
+<p>When the shell is waiting for a job or process using the <code class="code">wait</code>
+builtin, and job control is enabled, <code class="code">wait</code> will return when the
+job changes state. The <samp class="option">-f</samp> option causes <code class="code">wait</code> to wait
until the job or process terminates before returning.
</p>
<hr>
</div>
-<div class="section" id="Job-Control-Builtins">
-<div class="header">
+<div class="section-level-extent" id="Job-Control-Builtins">
+<div class="nav-panel">
<p>
Next: <a href="#Job-Control-Variables" accesskey="n" rel="next">Job Control Variables</a>, Previous: <a href="#Job-Control-Basics" accesskey="p" rel="prev">Job Control Basics</a>, Up: <a href="#Job-Control" accesskey="u" rel="up">Job Control</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Job-Control-Builtins-1"></span><h3 class="section">7.2 Job Control Builtins</h3>
+<h3 class="section" id="Job-Control-Builtins-1"><span>7.2 Job Control Builtins<a class="copiable-link" href="#Job-Control-Builtins-1"> ¶</a></span></h3>
-<dl compact="compact">
-<dt id='index-bg'><span><code>bg</code><a href='#index-bg' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-bg"></a><span><code class="code">bg</code><a class="copiable-link" href="#index-bg"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">bg [<var>jobspec</var> …]
+<pre class="example-preformatted">bg [<var class="var">jobspec</var> ...]
</pre></div>
-<p>Resume each suspended job <var>jobspec</var> in the background, as if it
-had been started with ‘<samp>&</samp>’.
-If <var>jobspec</var> is not supplied, the current job is used.
+<p>Resume each suspended job <var class="var">jobspec</var> in the background, as if it
+had been started with ‘<samp class="samp">&</samp>’.
+If <var class="var">jobspec</var> is not supplied, the current job is used.
The return status is zero unless it is run when job control is not
enabled, or, when run with job control enabled, any
-<var>jobspec</var> was not found or specifies a job
+<var class="var">jobspec</var> was not found or specifies a job
that was started without job control.
</p>
</dd>
-<dt id='index-fg'><span><code>fg</code><a href='#index-fg' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-fg"></a><span><code class="code">fg</code><a class="copiable-link" href="#index-fg"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">fg [<var>jobspec</var>]
+<pre class="example-preformatted">fg [<var class="var">jobspec</var>]
</pre></div>
-<p>Resume the job <var>jobspec</var> in the foreground and make it the current job.
-If <var>jobspec</var> is not supplied, the current job is used.
+<p>Resume the job <var class="var">jobspec</var> in the foreground and make it the current job.
+If <var class="var">jobspec</var> is not supplied, the current job is used.
The return status is that of the command placed into the foreground,
or non-zero if run when job control is disabled or, when run with
-job control enabled, <var>jobspec</var> does not specify a valid job or
-<var>jobspec</var> specifies a job that was started without job control.
+job control enabled, <var class="var">jobspec</var> does not specify a valid job or
+<var class="var">jobspec</var> specifies a job that was started without job control.
</p>
</dd>
-<dt id='index-jobs'><span><code>jobs</code><a href='#index-jobs' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-jobs"></a><span><code class="code">jobs</code><a class="copiable-link" href="#index-jobs"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">jobs [-lnprs] [<var>jobspec</var>]
-jobs -x <var>command</var> [<var>arguments</var>]
+<pre class="example-preformatted">jobs [-lnprs] [<var class="var">jobspec</var>]
+jobs -x <var class="var">command</var> [<var class="var">arguments</var>]
</pre></div>
<p>The first form lists the active jobs. The options have the
following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-l</code></span></dt>
-<dd><p>List process <small>ID</small>s in addition to the normal information.
+<dl class="table">
+<dt><code class="code">-l</code></dt>
+<dd><p>List process <small class="sc">ID</small>s in addition to the normal information.
</p>
</dd>
-<dt><span><code>-n</code></span></dt>
+<dt><code class="code">-n</code></dt>
<dd><p>Display information only about jobs that have changed status since
the user was last notified of their status.
</p>
</dd>
-<dt><span><code>-p</code></span></dt>
-<dd><p>List only the process <small>ID</small> of the job’s process group leader.
+<dt><code class="code">-p</code></dt>
+<dd><p>List only the process <small class="sc">ID</small> of the job’s process group leader.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
+<dt><code class="code">-r</code></dt>
<dd><p>Display only running jobs.
</p>
</dd>
-<dt><span><code>-s</code></span></dt>
+<dt><code class="code">-s</code></dt>
<dd><p>Display only stopped jobs.
</p></dd>
</dl>
-<p>If <var>jobspec</var> is given,
+<p>If <var class="var">jobspec</var> is given,
output is restricted to information about that job.
-If <var>jobspec</var> is not supplied, the status of all jobs is
+If <var class="var">jobspec</var> is not supplied, the status of all jobs is
listed.
</p>
-<p>If the <samp>-x</samp> option is supplied, <code>jobs</code> replaces any
-<var>jobspec</var> found in <var>command</var> or <var>arguments</var> with the
-corresponding process group <small>ID</small>, and executes <var>command</var>,
-passing it <var>argument</var>s, returning its exit status.
+<p>If the <samp class="option">-x</samp> option is supplied, <code class="code">jobs</code> replaces any
+<var class="var">jobspec</var> found in <var class="var">command</var> or <var class="var">arguments</var> with the
+corresponding process group <small class="sc">ID</small>, and executes <var class="var">command</var>,
+passing it <var class="var">argument</var>s, returning its exit status.
</p>
</dd>
-<dt id='index-kill'><span><code>kill</code><a href='#index-kill' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-kill"></a><span><code class="code">kill</code><a class="copiable-link" href="#index-kill"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">kill [-s <var>sigspec</var>] [-n <var>signum</var>] [-<var>sigspec</var>] <var>jobspec</var> or <var>pid</var>
-kill -l|-L [<var>exit_status</var>]
+<pre class="example-preformatted">kill [-s <var class="var">sigspec</var>] [-n <var class="var">signum</var>] [-<var class="var">sigspec</var>] <var class="var">jobspec</var> or <var class="var">pid</var>
+kill -l|-L [<var class="var">exit_status</var>]
</pre></div>
-<p>Send a signal specified by <var>sigspec</var> or <var>signum</var> to the process
-named by job specification <var>jobspec</var> or process <small>ID</small> <var>pid</var>.
-<var>sigspec</var> is either a case-insensitive signal name such as
-<code>SIGINT</code> (with or without the <code>SIG</code> prefix)
-or a signal number; <var>signum</var> is a signal number.
-If <var>sigspec</var> and <var>signum</var> are not present, <code>SIGTERM</code> is used.
-The <samp>-l</samp> option lists the signal names.
-If any arguments are supplied when <samp>-l</samp> is given, the names of the
+<p>Send a signal specified by <var class="var">sigspec</var> or <var class="var">signum</var> to the process
+named by job specification <var class="var">jobspec</var> or process <small class="sc">ID</small> <var class="var">pid</var>.
+<var class="var">sigspec</var> is either a case-insensitive signal name such as
+<code class="code">SIGINT</code> (with or without the <code class="code">SIG</code> prefix)
+or a signal number; <var class="var">signum</var> is a signal number.
+If <var class="var">sigspec</var> and <var class="var">signum</var> are not present, <code class="code">SIGTERM</code> is used.
+The <samp class="option">-l</samp> option lists the signal names.
+If any arguments are supplied when <samp class="option">-l</samp> is given, the names of the
signals corresponding to the arguments are listed, and the return status
is zero.
-<var>exit_status</var> is a number specifying a signal number or the exit
+<var class="var">exit_status</var> is a number specifying a signal number or the exit
status of a process terminated by a signal.
-The <samp>-L</samp> option is equivalent to <samp>-l</samp>.
+The <samp class="option">-L</samp> option is equivalent to <samp class="option">-l</samp>.
The return status is zero if at least one signal was successfully sent,
or non-zero if an error occurs or an invalid option is encountered.
</p>
</dd>
-<dt id='index-wait'><span><code>wait</code><a href='#index-wait' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-wait"></a><span><code class="code">wait</code><a class="copiable-link" href="#index-wait"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">wait [-fn] [-p <var>varname</var>] [<var>jobspec</var> or <var>pid</var> …]
+<pre class="example-preformatted">wait [-fn] [-p <var class="var">varname</var>] [<var class="var">jobspec</var> or <var class="var">pid</var> ...]
</pre></div>
-<p>Wait until the child process specified by each process <small>ID</small> <var>pid</var>
-or job specification <var>jobspec</var> exits and return the exit status of the
+<p>Wait until the child process specified by each process <small class="sc">ID</small> <var class="var">pid</var>
+or job specification <var class="var">jobspec</var> exits and return the exit status of the
last command waited for.
If a job spec is given, all processes in the job are waited for.
If no arguments are given,
-<code>wait</code> waits for all running background jobs and
+<code class="code">wait</code> waits for all running background jobs and
the last-executed process substitution, if its process id is the same as
-<var>$!</var>,
+<var class="var">$!</var>,
and the return status is zero.
-If the <samp>-n</samp> option is supplied, <code>wait</code> waits for a single job
-from the list of <var>pid</var>s or <var>jobspec</var>s or, if no arguments are
+If the <samp class="option">-n</samp> option is supplied, <code class="code">wait</code> waits for a single job
+from the list of <var class="var">pid</var>s or <var class="var">jobspec</var>s or, if no arguments are
supplied, any job,
to complete and returns its exit status.
If none of the supplied arguments is a child of the shell, or if no arguments
are supplied and the shell has no unwaited-for children, the exit status
is 127.
-If the <samp>-p</samp> option is supplied, the process or job identifier of the job
+If the <samp class="option">-p</samp> option is supplied, the process or job identifier of the job
for which the exit status is returned is assigned to the variable
-<var>varname</var> named by the option argument.
+<var class="var">varname</var> named by the option argument.
The variable will be unset initially, before any assignment.
-This is useful only when the <samp>-n</samp> option is supplied.
-Supplying the <samp>-f</samp> option, when job control is enabled,
-forces <code>wait</code> to wait for each <var>pid</var> or <var>jobspec</var> to
+This is useful only when the <samp class="option">-n</samp> option is supplied.
+Supplying the <samp class="option">-f</samp> option, when job control is enabled,
+forces <code class="code">wait</code> to wait for each <var class="var">pid</var> or <var class="var">jobspec</var> to
terminate before returning its status, instead of returning when it changes
status.
-If neither <var>jobspec</var> nor <var>pid</var> specifies an active child process
+If neither <var class="var">jobspec</var> nor <var class="var">pid</var> specifies an active child process
of the shell, the return status is 127.
-If <code>wait</code> is interrupted by a signal, the return status will be greater
-than 128, as described above (see <a href="#Signals">Signals</a>).
+If <code class="code">wait</code> is interrupted by a signal, the return status will be greater
+than 128, as described above (see <a class="pxref" href="#Signals">Signals</a>).
Otherwise, the return status is the exit status
of the last process or job waited for.
</p>
</dd>
-<dt id='index-disown'><span><code>disown</code><a href='#index-disown' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-disown"></a><span><code class="code">disown</code><a class="copiable-link" href="#index-disown"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">disown [-ar] [-h] [<var>jobspec</var> … | <var>pid</var> … ]
+<pre class="example-preformatted">disown [-ar] [-h] [<var class="var">jobspec</var> ... | <var class="var">pid</var> ... ]
</pre></div>
-<p>Without options, remove each <var>jobspec</var> from the table of
+<p>Without options, remove each <var class="var">jobspec</var> from the table of
active jobs.
-If the <samp>-h</samp> option is given, the job is not removed from the table,
-but is marked so that <code>SIGHUP</code> is not sent to the job if the shell
-receives a <code>SIGHUP</code>.
-If <var>jobspec</var> is not present, and neither the <samp>-a</samp> nor the
-<samp>-r</samp> option is supplied, the current job is used.
-If no <var>jobspec</var> is supplied, the <samp>-a</samp> option means to remove or
-mark all jobs; the <samp>-r</samp> option without a <var>jobspec</var>
+If the <samp class="option">-h</samp> option is given, the job is not removed from the table,
+but is marked so that <code class="code">SIGHUP</code> is not sent to the job if the shell
+receives a <code class="code">SIGHUP</code>.
+If <var class="var">jobspec</var> is not present, and neither the <samp class="option">-a</samp> nor the
+<samp class="option">-r</samp> option is supplied, the current job is used.
+If no <var class="var">jobspec</var> is supplied, the <samp class="option">-a</samp> option means to remove or
+mark all jobs; the <samp class="option">-r</samp> option without a <var class="var">jobspec</var>
argument restricts operation to running jobs.
</p>
</dd>
-<dt id='index-suspend'><span><code>suspend</code><a href='#index-suspend' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-suspend"></a><span><code class="code">suspend</code><a class="copiable-link" href="#index-suspend"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">suspend [-f]
+<pre class="example-preformatted">suspend [-f]
</pre></div>
<p>Suspend the execution of this shell until it receives a
-<code>SIGCONT</code> signal.
+<code class="code">SIGCONT</code> signal.
A login shell,
or a shell without job control enabled,
-cannot be suspended; the <samp>-f</samp>
+cannot be suspended; the <samp class="option">-f</samp>
option can be used to override this and force the suspension.
The return status is 0 unless the shell is a login shell
or job control is not enabled
and
-<samp>-f</samp>
+<samp class="option">-f</samp>
is not supplied.
</p>
</dd>
</dl>
-<p>When job control is not active, the <code>kill</code> and <code>wait</code>
-builtins do not accept <var>jobspec</var> arguments. They must be
-supplied process <small>ID</small>s.
+<p>When job control is not active, the <code class="code">kill</code> and <code class="code">wait</code>
+builtins do not accept <var class="var">jobspec</var> arguments. They must be
+supplied process <small class="sc">ID</small>s.
</p>
<hr>
</div>
-<div class="section" id="Job-Control-Variables">
-<div class="header">
+<div class="section-level-extent" id="Job-Control-Variables">
+<div class="nav-panel">
<p>
Previous: <a href="#Job-Control-Builtins" accesskey="p" rel="prev">Job Control Builtins</a>, Up: <a href="#Job-Control" accesskey="u" rel="up">Job Control</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Job-Control-Variables-1"></span><h3 class="section">7.3 Job Control Variables</h3>
+<h3 class="section" id="Job-Control-Variables-1"><span>7.3 Job Control Variables<a class="copiable-link" href="#Job-Control-Variables-1"> ¶</a></span></h3>
-<dl compact="compact">
-<dt id='index-auto_005fresume'><span><code>auto_resume</code><a href='#index-auto_005fresume' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="vtable">
+<dt><a id="index-auto_005fresume"></a><span><code class="code">auto_resume</code><a class="copiable-link" href="#index-auto_005fresume"> ¶</a></span></dt>
<dd><p>This variable controls how the shell interacts with the user and
job control. If this variable exists then single word simple
commands without redirections are treated as candidates for resumption
more than one job beginning with the string typed, then
the most recently accessed job will be selected.
The name of a stopped job, in this context, is the command line
-used to start it. If this variable is set to the value ‘<samp>exact</samp>’,
+used to start it. If this variable is set to the value ‘<samp class="samp">exact</samp>’,
the string supplied must match the name of a stopped job exactly;
-if set to ‘<samp>substring</samp>’,
+if set to ‘<samp class="samp">substring</samp>’,
the string supplied needs to match a substring of the name of a
-stopped job. The ‘<samp>substring</samp>’ value provides functionality
-analogous to the ‘<samp>%?</samp>’ job <small>ID</small> (see <a href="#Job-Control-Basics">Job Control Basics</a>).
+stopped job. The ‘<samp class="samp">substring</samp>’ value provides functionality
+analogous to the ‘<samp class="samp">%?</samp>’ job <small class="sc">ID</small> (see <a class="pxref" href="#Job-Control-Basics">Job Control Basics</a>).
If set to any other value, the supplied string must
be a prefix of a stopped job’s name; this provides functionality
-analogous to the ‘<samp>%</samp>’ job <small>ID</small>.
+analogous to the ‘<samp class="samp">%</samp>’ job <small class="sc">ID</small>.
</p>
</dd>
</dl>
-<span id="index-Readline_002c-how-to-use"></span>
+<a class="index-entry-id" id="index-Readline_002c-how-to-use"></a>
<hr>
</div>
</div>
-<div class="chapter" id="Command-Line-Editing">
-<div class="header">
+<div class="chapter-level-extent" id="Command-Line-Editing">
+<div class="nav-panel">
<p>
Next: <a href="#Using-History-Interactively" accesskey="n" rel="next">Using History Interactively</a>, Previous: <a href="#Job-Control" accesskey="p" rel="prev">Job Control</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Command-Line-Editing-1"></span><h2 class="chapter">8 Command Line Editing</h2>
+<h2 class="chapter" id="Command-Line-Editing-1"><span>8 Command Line Editing<a class="copiable-link" href="#Command-Line-Editing-1"> ¶</a></span></h2>
-<p>This chapter describes the basic features of the <small>GNU</small>
+<p>This chapter describes the basic features of the <small class="sc">GNU</small>
command line editing interface.
Command line editing is provided by the Readline library, which is
used by several different programs, including Bash.
Command line editing is enabled by default when using an interactive shell,
-unless the <samp>--noediting</samp> option is supplied at shell invocation.
-Line editing is also used when using the <samp>-e</samp> option to the
-<code>read</code> builtin command (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+unless the <samp class="option">--noediting</samp> option is supplied at shell invocation.
+Line editing is also used when using the <samp class="option">-e</samp> option to the
+<code class="code">read</code> builtin command (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
By default, the line editing commands are similar to those of Emacs.
A vi-style line editing interface is also available.
-Line editing can be enabled at any time using the <samp>-o emacs</samp> or
-<samp>-o vi</samp> options to the <code>set</code> builtin command
-(see <a href="#The-Set-Builtin">The Set Builtin</a>), or disabled using the <samp>+o emacs</samp> or
-<samp>+o vi</samp> options to <code>set</code>.
+Line editing can be enabled at any time using the <samp class="option">-o emacs</samp> or
+<samp class="option">-o vi</samp> options to the <code class="code">set</code> builtin command
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>), or disabled using the <samp class="option">+o emacs</samp> or
+<samp class="option">+o vi</samp> options to <code class="code">set</code>.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Introduction-and-Notation" accesskey="1">Introduction to Line Editing</a></li>
<li><a href="#Readline-Interaction" accesskey="2">Readline Interaction</a></li>
<li><a href="#Readline-Init-File" accesskey="3">Readline Init File</a></li>
<li><a href="#A-Programmable-Completion-Example" accesskey="8">A Programmable Completion Example</a></li>
</ul>
<hr>
-<div class="section" id="Introduction-and-Notation">
-<div class="header">
+<div class="section-level-extent" id="Introduction-and-Notation">
+<div class="nav-panel">
<p>
Next: <a href="#Readline-Interaction" accesskey="n" rel="next">Readline Interaction</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Introduction-to-Line-Editing"></span><h3 class="section">8.1 Introduction to Line Editing</h3>
+<h3 class="section" id="Introduction-to-Line-Editing"><span>8.1 Introduction to Line Editing<a class="copiable-link" href="#Introduction-to-Line-Editing"> ¶</a></span></h3>
<p>The following paragraphs describe the notation used to represent
keystrokes.
</p>
-<p>The text <kbd>C-k</kbd> is read as ‘Control-K’ and describes the character
-produced when the <tt class="key">k</tt> key is pressed while the Control key
+<p>The text <kbd class="kbd">C-k</kbd> is read as ‘Control-K’ and describes the character
+produced when the <kbd class="key">k</kbd> key is pressed while the Control key
is depressed.
</p>
-<p>The text <kbd>M-k</kbd> is read as ‘Meta-K’ and describes the character
-produced when the Meta key (if you have one) is depressed, and the <tt class="key">k</tt>
+<p>The text <kbd class="kbd">M-k</kbd> is read as ‘Meta-K’ and describes the character
+produced when the Meta key (if you have one) is depressed, and the <kbd class="key">k</kbd>
key is pressed.
-The Meta key is labeled <tt class="key">ALT</tt> on many keyboards.
-On keyboards with two keys labeled <tt class="key">ALT</tt> (usually to either side of
-the space bar), the <tt class="key">ALT</tt> on the left side is generally set to
+The Meta key is labeled <kbd class="key">ALT</kbd> on many keyboards.
+On keyboards with two keys labeled <kbd class="key">ALT</kbd> (usually to either side of
+the space bar), the <kbd class="key">ALT</kbd> on the left side is generally set to
work as a Meta key.
-The <tt class="key">ALT</tt> key on the right may also be configured to work as a
+The <kbd class="key">ALT</kbd> key on the right may also be configured to work as a
Meta key or may be configured as some other modifier, such as a
Compose key for typing accented characters.
</p>
-<p>If you do not have a Meta or <tt class="key">ALT</tt> key, or another key working as
-a Meta key, the identical keystroke can be generated by typing <tt class="key">ESC</tt>
-<em>first</em>, and then typing <tt class="key">k</tt>.
-Either process is known as <em>metafying</em> the <tt class="key">k</tt> key.
+<p>If you do not have a Meta or <kbd class="key">ALT</kbd> key, or another key working as
+a Meta key, the identical keystroke can be generated by typing <kbd class="key">ESC</kbd>
+<em class="emph">first</em>, and then typing <kbd class="key">k</kbd>.
+Either process is known as <em class="dfn">metafying</em> the <kbd class="key">k</kbd> key.
</p>
-<p>The text <kbd>M-C-k</kbd> is read as ‘Meta-Control-k’ and describes the
-character produced by <em>metafying</em> <kbd>C-k</kbd>.
+<p>The text <kbd class="kbd">M-C-k</kbd> is read as ‘Meta-Control-k’ and describes the
+character produced by <em class="dfn">metafying</em> <kbd class="kbd">C-k</kbd>.
</p>
<p>In addition, several keys have their own names. Specifically,
-<tt class="key">DEL</tt>, <tt class="key">ESC</tt>, <tt class="key">LFD</tt>, <tt class="key">SPC</tt>, <tt class="key">RET</tt>, and <tt class="key">TAB</tt> all
+<kbd class="key">DEL</kbd>, <kbd class="key">ESC</kbd>, <kbd class="key">LFD</kbd>, <kbd class="key">SPC</kbd>, <kbd class="key">RET</kbd>, and <kbd class="key">TAB</kbd> all
stand for themselves when seen in this text, or in an init file
-(see <a href="#Readline-Init-File">Readline Init File</a>).
-If your keyboard lacks a <tt class="key">LFD</tt> key, typing <tt class="key">C-j</tt> will
+(see <a class="pxref" href="#Readline-Init-File">Readline Init File</a>).
+If your keyboard lacks a <kbd class="key">LFD</kbd> key, typing <kbd class="key">C-j</kbd> will
produce the desired character.
-The <tt class="key">RET</tt> key may be labeled <tt class="key">Return</tt> or <tt class="key">Enter</tt> on
+The <kbd class="key">RET</kbd> key may be labeled <kbd class="key">Return</kbd> or <kbd class="key">Enter</kbd> on
some keyboards.
</p>
<hr>
</div>
-<div class="section" id="Readline-Interaction">
-<div class="header">
+<div class="section-level-extent" id="Readline-Interaction">
+<div class="nav-panel">
<p>
Next: <a href="#Readline-Init-File" accesskey="n" rel="next">Readline Init File</a>, Previous: <a href="#Introduction-and-Notation" accesskey="p" rel="prev">Introduction to Line Editing</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Interaction-1"></span><h3 class="section">8.2 Readline Interaction</h3>
-<span id="index-interaction_002c-readline"></span>
+<h3 class="section" id="Readline-Interaction-1"><span>8.2 Readline Interaction<a class="copiable-link" href="#Readline-Interaction-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-interaction_002c-readline"></a>
<p>Often during an interactive session you type in a long line of text,
only to notice that the first word on the line is misspelled. The
you to retype the majority of the line. Using these editing commands,
you move the cursor to the place that needs correction, and delete or
insert the text of the corrections. Then, when you are satisfied with
-the line, you simply press <tt class="key">RET</tt>. You do not have to be at the
-end of the line to press <tt class="key">RET</tt>; the entire line is accepted
+the line, you simply press <kbd class="key">RET</kbd>. You do not have to be at the
+end of the line to press <kbd class="key">RET</kbd>; the entire line is accepted
regardless of the location of the cursor within the line.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Readline-Bare-Essentials" accesskey="1">Readline Bare Essentials</a></li>
<li><a href="#Readline-Movement-Commands" accesskey="2">Readline Movement Commands</a></li>
<li><a href="#Readline-Killing-Commands" accesskey="3">Readline Killing Commands</a></li>
<li><a href="#Searching" accesskey="5">Searching for Commands in the History</a></li>
</ul>
<hr>
-<div class="subsection" id="Readline-Bare-Essentials">
-<div class="header">
+<div class="subsection-level-extent" id="Readline-Bare-Essentials">
+<div class="nav-panel">
<p>
Next: <a href="#Readline-Movement-Commands" accesskey="n" rel="next">Readline Movement Commands</a>, Up: <a href="#Readline-Interaction" accesskey="u" rel="up">Readline Interaction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Bare-Essentials-1"></span><h4 class="subsection">8.2.1 Readline Bare Essentials</h4>
-<span id="index-notation_002c-readline"></span>
-<span id="index-command-editing"></span>
-<span id="index-editing-command-lines"></span>
+<h4 class="subsection" id="Readline-Bare-Essentials-1"><span>8.2.1 Readline Bare Essentials<a class="copiable-link" href="#Readline-Bare-Essentials-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-notation_002c-readline"></a>
+<a class="index-entry-id" id="index-command-editing"></a>
+<a class="index-entry-id" id="index-editing-command-lines"></a>
<p>In order to enter characters into the line, simply type them. The typed
character appears where the cursor was, and then the cursor moves one
</p>
<p>Sometimes you may mistype a character, and
not notice the error until you have typed several other characters. In
-that case, you can type <kbd>C-b</kbd> to move the cursor to the left, and then
+that case, you can type <kbd class="kbd">C-b</kbd> to move the cursor to the left, and then
correct your mistake. Afterwards, you can move the cursor to the right
-with <kbd>C-f</kbd>.
+with <kbd class="kbd">C-f</kbd>.
</p>
<p>When you add text in the middle of a line, you will notice that characters
to the right of the cursor are ‘pushed over’ to make room for the text
blank space created by the removal of the text. A list of the bare
essentials for editing the text of an input line follows.
</p>
-<dl compact="compact">
-<dt><span><kbd>C-b</kbd></span></dt>
+<dl class="table">
+<dt><kbd class="kbd">C-b</kbd></dt>
<dd><p>Move back one character.
</p></dd>
-<dt><span><kbd>C-f</kbd></span></dt>
+<dt><kbd class="kbd">C-f</kbd></dt>
<dd><p>Move forward one character.
</p></dd>
-<dt><span><tt class="key">DEL</tt> or <tt class="key">Backspace</tt></span></dt>
+<dt><kbd class="key">DEL</kbd> or <kbd class="key">Backspace</kbd></dt>
<dd><p>Delete the character to the left of the cursor.
</p></dd>
-<dt><span><kbd>C-d</kbd></span></dt>
+<dt><kbd class="kbd">C-d</kbd></dt>
<dd><p>Delete the character underneath the cursor.
</p></dd>
-<dt><span>Printing characters<!-- /@w --></span></dt>
+<dt>Printing characters<!-- /@w --></dt>
<dd><p>Insert the character into the line at the cursor.
</p></dd>
-<dt><span><kbd>C-_</kbd> or <kbd>C-x C-u</kbd></span></dt>
+<dt><kbd class="kbd">C-_</kbd> or <kbd class="kbd">C-x C-u</kbd></dt>
<dd><p>Undo the last editing command. You can undo all the way back to an
empty line.
</p></dd>
</dl>
-<p>(Depending on your configuration, the <tt class="key">Backspace</tt> key might be set to
-delete the character to the left of the cursor and the <tt class="key">DEL</tt> key set
-to delete the character underneath the cursor, like <kbd>C-d</kbd>, rather
+<p>(Depending on your configuration, the <kbd class="key">Backspace</kbd> key might be set to
+delete the character to the left of the cursor and the <kbd class="key">DEL</kbd> key set
+to delete the character underneath the cursor, like <kbd class="kbd">C-d</kbd>, rather
than the character to the left of the cursor.)
</p>
<hr>
</div>
-<div class="subsection" id="Readline-Movement-Commands">
-<div class="header">
+<div class="subsection-level-extent" id="Readline-Movement-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Readline-Killing-Commands" accesskey="n" rel="next">Readline Killing Commands</a>, Previous: <a href="#Readline-Bare-Essentials" accesskey="p" rel="prev">Readline Bare Essentials</a>, Up: <a href="#Readline-Interaction" accesskey="u" rel="up">Readline Interaction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Movement-Commands-1"></span><h4 class="subsection">8.2.2 Readline Movement Commands</h4>
+<h4 class="subsection" id="Readline-Movement-Commands-1"><span>8.2.2 Readline Movement Commands<a class="copiable-link" href="#Readline-Movement-Commands-1"> ¶</a></span></h4>
<p>The above table describes the most basic keystrokes that you need
in order to do editing of the input line. For your convenience, many
-other commands have been added in addition to <kbd>C-b</kbd>, <kbd>C-f</kbd>,
-<kbd>C-d</kbd>, and <tt class="key">DEL</tt>. Here are some commands for moving more rapidly
+other commands have been added in addition to <kbd class="kbd">C-b</kbd>, <kbd class="kbd">C-f</kbd>,
+<kbd class="kbd">C-d</kbd>, and <kbd class="key">DEL</kbd>. Here are some commands for moving more rapidly
about the line.
</p>
-<dl compact="compact">
-<dt><span><kbd>C-a</kbd></span></dt>
+<dl class="table">
+<dt><kbd class="kbd">C-a</kbd></dt>
<dd><p>Move to the start of the line.
</p></dd>
-<dt><span><kbd>C-e</kbd></span></dt>
+<dt><kbd class="kbd">C-e</kbd></dt>
<dd><p>Move to the end of the line.
</p></dd>
-<dt><span><kbd>M-f</kbd></span></dt>
+<dt><kbd class="kbd">M-f</kbd></dt>
<dd><p>Move forward a word, where a word is composed of letters and digits.
</p></dd>
-<dt><span><kbd>M-b</kbd></span></dt>
+<dt><kbd class="kbd">M-b</kbd></dt>
<dd><p>Move backward a word.
</p></dd>
-<dt><span><kbd>C-l</kbd></span></dt>
+<dt><kbd class="kbd">C-l</kbd></dt>
<dd><p>Clear the screen, reprinting the current line at the top.
</p></dd>
</dl>
-<p>Notice how <kbd>C-f</kbd> moves forward a character, while <kbd>M-f</kbd> moves
+<p>Notice how <kbd class="kbd">C-f</kbd> moves forward a character, while <kbd class="kbd">M-f</kbd> moves
forward a word. It is a loose convention that control keystrokes
operate on characters while meta keystrokes operate on words.
</p>
<hr>
</div>
-<div class="subsection" id="Readline-Killing-Commands">
-<div class="header">
+<div class="subsection-level-extent" id="Readline-Killing-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Readline-Arguments" accesskey="n" rel="next">Readline Arguments</a>, Previous: <a href="#Readline-Movement-Commands" accesskey="p" rel="prev">Readline Movement Commands</a>, Up: <a href="#Readline-Interaction" accesskey="u" rel="up">Readline Interaction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Killing-Commands-1"></span><h4 class="subsection">8.2.3 Readline Killing Commands</h4>
+<h4 class="subsection" id="Readline-Killing-Commands-1"><span>8.2.3 Readline Killing Commands<a class="copiable-link" href="#Readline-Killing-Commands-1"> ¶</a></span></h4>
-<span id="index-killing-text"></span>
-<span id="index-yanking-text"></span>
+<a class="index-entry-id" id="index-killing-text"></a>
+<a class="index-entry-id" id="index-yanking-text"></a>
-<p><em>Killing</em> text means to delete the text from the line, but to save
-it away for later use, usually by <em>yanking</em> (re-inserting)
+<p><em class="dfn">Killing</em> text means to delete the text from the line, but to save
+it away for later use, usually by <em class="dfn">yanking</em> (re-inserting)
it back into the line.
(‘Cut’ and ‘paste’ are more recent jargon for ‘kill’ and ‘yank’.)
</p>
be sure that you can get the text back in a different (or the same)
place later.
</p>
-<p>When you use a kill command, the text is saved in a <em>kill-ring</em>.
+<p>When you use a kill command, the text is saved in a <em class="dfn">kill-ring</em>.
Any number of consecutive kills save all of the killed text together, so
that when you yank it back, you get it all. The kill
ring is not line specific; the text that you killed on a previously
typed line is available to be yanked back later, when you are typing
another line.
-<span id="index-kill-ring"></span>
+<a class="index-entry-id" id="index-kill-ring"></a>
</p>
<p>Here is the list of commands for killing text.
</p>
-<dl compact="compact">
-<dt><span><kbd>C-k</kbd></span></dt>
+<dl class="table">
+<dt><kbd class="kbd">C-k</kbd></dt>
<dd><p>Kill the text from the current cursor position to the end of the line.
</p>
</dd>
-<dt><span><kbd>M-d</kbd></span></dt>
+<dt><kbd class="kbd">M-d</kbd></dt>
<dd><p>Kill from the cursor to the end of the current word, or, if between
words, to the end of the next word.
-Word boundaries are the same as those used by <kbd>M-f</kbd>.
+Word boundaries are the same as those used by <kbd class="kbd">M-f</kbd>.
</p>
</dd>
-<dt><span><kbd>M-<span class="key">DEL</span></kbd></span></dt>
+<dt><kbd class="kbd">M-<kbd class="key">DEL</kbd></kbd></dt>
<dd><p>Kill from the cursor to the start of the current word, or, if between
words, to the start of the previous word.
-Word boundaries are the same as those used by <kbd>M-b</kbd>.
+Word boundaries are the same as those used by <kbd class="kbd">M-b</kbd>.
</p>
</dd>
-<dt><span><kbd>C-w</kbd></span></dt>
+<dt><kbd class="kbd">C-w</kbd></dt>
<dd><p>Kill from the cursor to the previous whitespace. This is different than
-<kbd>M-<span class="key">DEL</span></kbd> because the word boundaries differ.
+<kbd class="kbd">M-<kbd class="key">DEL</kbd></kbd> because the word boundaries differ.
</p>
</dd>
</dl>
-<p>Here is how to <em>yank</em> the text back into the line. Yanking
+<p>Here is how to <em class="dfn">yank</em> the text back into the line. Yanking
means to copy the most-recently-killed text from the kill buffer.
</p>
-<dl compact="compact">
-<dt><span><kbd>C-y</kbd></span></dt>
+<dl class="table">
+<dt><kbd class="kbd">C-y</kbd></dt>
<dd><p>Yank the most recently killed text back into the buffer at the cursor.
</p>
</dd>
-<dt><span><kbd>M-y</kbd></span></dt>
+<dt><kbd class="kbd">M-y</kbd></dt>
<dd><p>Rotate the kill-ring, and yank the new top. You can only do this if
-the prior command is <kbd>C-y</kbd> or <kbd>M-y</kbd>.
+the prior command is <kbd class="kbd">C-y</kbd> or <kbd class="kbd">M-y</kbd>.
</p></dd>
</dl>
<hr>
</div>
-<div class="subsection" id="Readline-Arguments">
-<div class="header">
+<div class="subsection-level-extent" id="Readline-Arguments">
+<div class="nav-panel">
<p>
Next: <a href="#Searching" accesskey="n" rel="next">Searching for Commands in the History</a>, Previous: <a href="#Readline-Killing-Commands" accesskey="p" rel="prev">Readline Killing Commands</a>, Up: <a href="#Readline-Interaction" accesskey="u" rel="up">Readline Interaction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Arguments-1"></span><h4 class="subsection">8.2.4 Readline Arguments</h4>
+<h4 class="subsection" id="Readline-Arguments-1"><span>8.2.4 Readline Arguments<a class="copiable-link" href="#Readline-Arguments-1"> ¶</a></span></h4>
<p>You can pass numeric arguments to Readline commands. Sometimes the
-argument acts as a repeat count, other times it is the <i>sign</i> of the
+argument acts as a repeat count, other times it is the <i class="i">sign</i> of the
argument that is significant. If you pass a negative argument to a
command which normally acts in a forward direction, that command will
act in a backward direction. For example, to kill text back to the
-start of the line, you might type ‘<samp>M-- C-k</samp>’.
+start of the line, you might type ‘<samp class="samp">M-- C-k</samp>’.
</p>
<p>The general way to pass numeric arguments to a command is to type meta
digits before the command. If the first ‘digit’ typed is a minus
-sign (‘<samp>-</samp>’), then the sign of the argument will be negative. Once
+sign (‘<samp class="samp">-</samp>’), then the sign of the argument will be negative. Once
you have typed one meta digit to get the argument started, you can type
the remainder of the digits, and then the command. For example, to give
-the <kbd>C-d</kbd> command an argument of 10, you could type ‘<samp>M-1 0 C-d</samp>’,
+the <kbd class="kbd">C-d</kbd> command an argument of 10, you could type ‘<samp class="samp">M-1 0 C-d</samp>’,
which will delete the next ten characters on the input line.
</p>
<hr>
</div>
-<div class="subsection" id="Searching">
-<div class="header">
+<div class="subsection-level-extent" id="Searching">
+<div class="nav-panel">
<p>
Previous: <a href="#Readline-Arguments" accesskey="p" rel="prev">Readline Arguments</a>, Up: <a href="#Readline-Interaction" accesskey="u" rel="up">Readline Interaction</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Searching-for-Commands-in-the-History"></span><h4 class="subsection">8.2.5 Searching for Commands in the History</h4>
+<h4 class="subsection" id="Searching-for-Commands-in-the-History"><span>8.2.5 Searching for Commands in the History<a class="copiable-link" href="#Searching-for-Commands-in-the-History"> ¶</a></span></h4>
<p>Readline provides commands for searching through the command history
-(see <a href="#Bash-History-Facilities">Bash History Facilities</a>)
+(see <a class="pxref" href="#Bash-History-Facilities">Bash History Facilities</a>)
for lines containing a specified string.
-There are two search modes: <em>incremental</em> and <em>non-incremental</em>.
+There are two search modes: <em class="dfn">incremental</em> and <em class="dfn">non-incremental</em>.
</p>
<p>Incremental searches begin before the user has finished typing the
search string.
An incremental search requires only as many characters as needed to
find the desired history entry.
To search backward in the history for a particular string, type
-<kbd>C-r</kbd>. Typing <kbd>C-s</kbd> searches forward through the history.
-The characters present in the value of the <code>isearch-terminators</code> variable
+<kbd class="kbd">C-r</kbd>. Typing <kbd class="kbd">C-s</kbd> searches forward through the history.
+The characters present in the value of the <code class="code">isearch-terminators</code> variable
are used to terminate an incremental search.
-If that variable has not been assigned a value, the <tt class="key">ESC</tt> and
-<kbd>C-J</kbd> characters will terminate an incremental search.
-<kbd>C-g</kbd> will abort an incremental search and restore the original line.
+If that variable has not been assigned a value, the <kbd class="key">ESC</kbd> and
+<kbd class="kbd">C-J</kbd> characters will terminate an incremental search.
+<kbd class="kbd">C-g</kbd> will abort an incremental search and restore the original line.
When the search is terminated, the history entry containing the
search string becomes the current line.
</p>
-<p>To find other matching entries in the history list, type <kbd>C-r</kbd> or
-<kbd>C-s</kbd> as appropriate.
+<p>To find other matching entries in the history list, type <kbd class="kbd">C-r</kbd> or
+<kbd class="kbd">C-s</kbd> as appropriate.
This will search backward or forward in the history for the next
entry matching the search string typed so far.
Any other key sequence bound to a Readline command will terminate
the search and execute that command.
-For instance, a <tt class="key">RET</tt> will terminate the search and accept
+For instance, a <kbd class="key">RET</kbd> will terminate the search and accept
the line, thereby executing the command from the history list.
A movement command will terminate the search, make the last line found
the current line, and begin editing.
</p>
-<p>Readline remembers the last incremental search string. If two
-<kbd>C-r</kbd>s are typed without any intervening characters defining a new
-search string, any remembered search string is used.
+<p>Readline remembers the last incremental search string.
+If two <kbd class="kbd">C-r</kbd>s are typed without any intervening characters defining
+a new search string, Readline uses any remembered search string.
</p>
<p>Non-incremental searches read the entire search string before starting
-to search for matching history lines. The search string may be
-typed by the user or be part of the contents of the current line.
+to search for matching history lines.
+The search string may be typed by the user or be part of the contents of
+the current line.
</p>
<hr>
</div>
</div>
-<div class="section" id="Readline-Init-File">
-<div class="header">
+<div class="section-level-extent" id="Readline-Init-File">
+<div class="nav-panel">
<p>
Next: <a href="#Bindable-Readline-Commands" accesskey="n" rel="next">Bindable Readline Commands</a>, Previous: <a href="#Readline-Interaction" accesskey="p" rel="prev">Readline Interaction</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Init-File-1"></span><h3 class="section">8.3 Readline Init File</h3>
-<span id="index-initialization-file_002c-readline"></span>
+<h3 class="section" id="Readline-Init-File-1"><span>8.3 Readline Init File<a class="copiable-link" href="#Readline-Init-File-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-initialization-file_002c-readline"></a>
<p>Although the Readline library comes with a set of Emacs-like
keybindings installed by default, it is possible to use a different set
of keybindings.
Any user can customize programs that use Readline by putting
-commands in an <em>inputrc</em> file,
+commands in an <em class="dfn">inputrc</em> file,
conventionally in their home directory.
The name of this
-file is taken from the value of the shell variable <code>INPUTRC</code>. If
-that variable is unset, the default is <samp>~/.inputrc</samp>. If that
+file is taken from the value of the shell variable <code class="env">INPUTRC</code>. If
+that variable is unset, the default is <samp class="file">~/.inputrc</samp>. If that
file does not exist or cannot be read, the ultimate default is
-<samp>/etc/inputrc</samp>.
-The <code>bind</code><!-- /@w --> builtin command can also be used to set Readline
+<samp class="file">/etc/inputrc</samp>.
+The <code class="code">bind</code><!-- /@w --> builtin command can also be used to set Readline
keybindings and variables.
-See <a href="#Bash-Builtins">Bash Builtin Commands</a>.
+See <a class="xref" href="#Bash-Builtins">Bash Builtin Commands</a>.
</p>
<p>When a program which uses the Readline library starts up, the
init file is read, and the key bindings are set.
</p>
-<p>In addition, the <code>C-x C-r</code> command re-reads this init file, thus
+<p>In addition, the <code class="code">C-x C-r</code> command re-reads this init file, thus
incorporating any changes that you might have made to it.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Readline-Init-File-Syntax" accesskey="1">Readline Init File Syntax</a></li>
<li><a href="#Conditional-Init-Constructs" accesskey="2">Conditional Init Constructs</a></li>
<li><a href="#Sample-Init-File" accesskey="3">Sample Init File</a></li>
</ul>
<hr>
-<div class="subsection" id="Readline-Init-File-Syntax">
-<div class="header">
+<div class="subsection-level-extent" id="Readline-Init-File-Syntax">
+<div class="nav-panel">
<p>
Next: <a href="#Conditional-Init-Constructs" accesskey="n" rel="next">Conditional Init Constructs</a>, Up: <a href="#Readline-Init-File" accesskey="u" rel="up">Readline Init File</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-Init-File-Syntax-1"></span><h4 class="subsection">8.3.1 Readline Init File Syntax</h4>
+<h4 class="subsection" id="Readline-Init-File-Syntax-1"><span>8.3.1 Readline Init File Syntax<a class="copiable-link" href="#Readline-Init-File-Syntax-1"> ¶</a></span></h4>
<p>There are only a few basic constructs allowed in the
Readline init file. Blank lines are ignored.
-Lines beginning with a ‘<samp>#</samp>’ are comments.
-Lines beginning with a ‘<samp>$</samp>’ indicate conditional
-constructs (see <a href="#Conditional-Init-Constructs">Conditional Init Constructs</a>). Other lines
+Lines beginning with a ‘<samp class="samp">#</samp>’ are comments.
+Lines beginning with a ‘<samp class="samp">$</samp>’ indicate conditional
+constructs (see <a class="pxref" href="#Conditional-Init-Constructs">Conditional Init Constructs</a>). Other lines
denote variable settings and key bindings.
</p>
-<dl compact="compact">
-<dt><span>Variable Settings</span></dt>
+<dl class="table">
+<dt>Variable Settings</dt>
<dd><p>You can modify the run-time behavior of Readline by
altering the values of variables in Readline
-using the <code>set</code> command within the init file.
+using the <code class="code">set</code> command within the init file.
The syntax is simple:
</p>
<div class="example">
-<pre class="example">set <var>variable</var> <var>value</var>
+<pre class="example-preformatted">set <var class="var">variable</var> <var class="var">value</var>
</pre></div>
<p>Here, for example, is how to
change from the default Emacs-like key binding to use
-<code>vi</code> line editing commands:
+<code class="code">vi</code> line editing commands:
</p>
<div class="example">
-<pre class="example">set editing-mode vi
+<pre class="example-preformatted">set editing-mode vi
</pre></div>
<p>Variable names and values, where appropriate, are recognized without regard
-to case. Unrecognized variable names are ignored.
+to case.
+Unrecognized variable names are ignored.
</p>
<p>Boolean variables (those that can be set to on or off) are set to on if
-the value is null or empty, <var>on</var> (case-insensitive), or 1. Any other
-value results in the variable being set to off.
+the value is null or empty, <var class="var">on</var> (case-insensitive), or 1.
+Any other value results in the variable being set to off.
</p>
-<p>The <code>bind <span class="nolinebreak">-V</span></code><!-- /@w --> command lists the current Readline variable names
-and values. See <a href="#Bash-Builtins">Bash Builtin Commands</a>.
+<p>The <code class="code">bind -V</code><!-- /@w --> command lists the current Readline variable names
+and values. See <a class="xref" href="#Bash-Builtins">Bash Builtin Commands</a>.
</p>
<p>A great deal of run-time behavior is changeable with the following
variables.
</p>
-<span id="index-variables_002c-readline"></span>
-<dl compact="compact">
-<dt id='index-active_002dregion_002dstart_002dcolor'><span><code>active-region-start-color</code><a href='#index-active_002dregion_002dstart_002dcolor' class='copiable-anchor'> ¶</a></span></dt>
+<a class="index-entry-id" id="index-variables_002c-readline"></a>
+<dl class="table">
+<dt><a id="index-active_002dregion_002dstart_002dcolor"></a><span><code class="code">active-region-start-color</code><a class="copiable-link" href="#index-active_002dregion_002dstart_002dcolor"> ¶</a></span></dt>
<dd><p>A string variable that controls the text color and background when displaying
the text in the active region (see the description of
-<code>enable-active-region</code> below).
+<code class="code">enable-active-region</code> below).
This string must not take up any physical character positions on the display,
so it should consist only of terminal escape sequences.
It is output to the terminal before displaying the text in the active region.
This variable is reset to the default value whenever the terminal type changes.
The default value is the string that puts the terminal in standout mode,
as obtained from the terminal’s terminfo description.
-A sample value might be ‘<samp>\e[01;33m</samp>’.
+A sample value might be ‘<samp class="samp">\e[01;33m</samp>’.
</p>
</dd>
-<dt id='index-active_002dregion_002dend_002dcolor'><span><code>active-region-end-color</code><a href='#index-active_002dregion_002dend_002dcolor' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A string variable that "undoes" the effects of <code>active-region-start-color</code>
+<dt><a id="index-active_002dregion_002dend_002dcolor"></a><span><code class="code">active-region-end-color</code><a class="copiable-link" href="#index-active_002dregion_002dend_002dcolor"> ¶</a></span></dt>
+<dd><p>A string variable that "undoes" the effects of <code class="code">active-region-start-color</code>
and restores "normal" terminal display appearance after displaying text
in the active region.
This string must not take up any physical character positions on the display,
This variable is reset to the default value whenever the terminal type changes.
The default value is the string that restores the terminal from standout mode,
as obtained from the terminal’s terminfo description.
-A sample value might be ‘<samp>\e[0m</samp>’.
+A sample value might be ‘<samp class="samp">\e[0m</samp>’.
</p>
</dd>
-<dt id='index-bell_002dstyle'><span><code>bell-style</code><a href='#index-bell_002dstyle' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-bell_002dstyle"></a><span><code class="code">bell-style</code><a class="copiable-link" href="#index-bell_002dstyle"> ¶</a></span></dt>
<dd><p>Controls what happens when Readline wants to ring the terminal bell.
-If set to ‘<samp>none</samp>’, Readline never rings the bell. If set to
-‘<samp>visible</samp>’, Readline uses a visible bell if one is available.
-If set to ‘<samp>audible</samp>’ (the default), Readline attempts to ring
+If set to ‘<samp class="samp">none</samp>’, Readline never rings the bell. If set to
+‘<samp class="samp">visible</samp>’, Readline uses a visible bell if one is available.
+If set to ‘<samp class="samp">audible</samp>’ (the default), Readline attempts to ring
the terminal’s bell.
</p>
</dd>
-<dt id='index-bind_002dtty_002dspecial_002dchars'><span><code>bind-tty-special-chars</code><a href='#index-bind_002dtty_002dspecial_002dchars' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’ (the default), Readline attempts to bind the control
+<dt><a id="index-bind_002dtty_002dspecial_002dchars"></a><span><code class="code">bind-tty-special-chars</code><a class="copiable-link" href="#index-bind_002dtty_002dspecial_002dchars"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’ (the default), Readline attempts to bind the control
characters that are
treated specially by the kernel’s terminal driver to their
Readline equivalents.
These override the default Readline bindings described here.
-Type ‘<samp>stty -a</samp>’ at a Bash prompt to see your current terminal settings,
-including the special control characters (usually <code>cchars</code>).
+Type ‘<samp class="samp">stty -a</samp>’ at a Bash prompt to see your current terminal settings,
+including the special control characters (usually <code class="code">cchars</code>).
</p>
</dd>
-<dt id='index-blink_002dmatching_002dparen'><span><code>blink-matching-paren</code><a href='#index-blink_002dmatching_002dparen' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline attempts to briefly move the cursor to an
+<dt><a id="index-blink_002dmatching_002dparen"></a><span><code class="code">blink-matching-paren</code><a class="copiable-link" href="#index-blink_002dmatching_002dparen"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline attempts to briefly move the cursor to an
opening parenthesis when a closing parenthesis is inserted. The default
-is ‘<samp>off</samp>’.
+is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-colored_002dcompletion_002dprefix'><span><code>colored-completion-prefix</code><a href='#index-colored_002dcompletion_002dprefix' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, when listing completions, Readline displays the
+<dt><a id="index-colored_002dcompletion_002dprefix"></a><span><code class="code">colored-completion-prefix</code><a class="copiable-link" href="#index-colored_002dcompletion_002dprefix"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, when listing completions, Readline displays the
common prefix of the set of possible completions using a different color.
-The color definitions are taken from the value of the <code>LS_COLORS</code>
+The color definitions are taken from the value of the <code class="env">LS_COLORS</code>
environment variable.
-If there is a color definition in <code>LS_COLORS</code> for the custom suffix
-‘<samp>readline-colored-completion-prefix</samp>’, Readline uses this color for
+If there is a color definition in <code class="env">LS_COLORS</code> for the custom suffix
+‘<samp class="samp">readline-colored-completion-prefix</samp>’, Readline uses this color for
the common prefix instead of its default.
-The default is ‘<samp>off</samp>’.
+The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-colored_002dstats'><span><code>colored-stats</code><a href='#index-colored_002dstats' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline displays possible completions using different
+<dt><a id="index-colored_002dstats"></a><span><code class="code">colored-stats</code><a class="copiable-link" href="#index-colored_002dstats"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline displays possible completions using different
colors to indicate their file type.
-The color definitions are taken from the value of the <code>LS_COLORS</code>
+The color definitions are taken from the value of the <code class="env">LS_COLORS</code>
environment variable.
-The default is ‘<samp>off</samp>’.
+The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-comment_002dbegin'><span><code>comment-begin</code><a href='#index-comment_002dbegin' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-comment_002dbegin"></a><span><code class="code">comment-begin</code><a class="copiable-link" href="#index-comment_002dbegin"> ¶</a></span></dt>
<dd><p>The string to insert at the beginning of the line when the
-<code>insert-comment</code> command is executed. The default value
-is <code>"#"</code>.
+<code class="code">insert-comment</code> command is executed. The default value
+is <code class="code">"#"</code>.
</p>
</dd>
-<dt id='index-completion_002ddisplay_002dwidth'><span><code>completion-display-width</code><a href='#index-completion_002ddisplay_002dwidth' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-completion_002ddisplay_002dwidth"></a><span><code class="code">completion-display-width</code><a class="copiable-link" href="#index-completion_002ddisplay_002dwidth"> ¶</a></span></dt>
<dd><p>The number of screen columns used to display possible matches
when performing completion.
The value is ignored if it is less than 0 or greater than the terminal
The default value is -1.
</p>
</dd>
-<dt id='index-completion_002dignore_002dcase'><span><code>completion-ignore-case</code><a href='#index-completion_002dignore_002dcase' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline performs filename matching and completion
+<dt><a id="index-completion_002dignore_002dcase"></a><span><code class="code">completion-ignore-case</code><a class="copiable-link" href="#index-completion_002dignore_002dcase"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline performs filename matching and completion
in a case-insensitive fashion.
-The default value is ‘<samp>off</samp>’.
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-completion_002dmap_002dcase'><span><code>completion-map-case</code><a href='#index-completion_002dmap_002dcase' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, and <var>completion-ignore-case</var> is enabled, Readline
-treats hyphens (‘<samp>-</samp>’) and underscores (‘<samp>_</samp>’) as equivalent when
+<dt><a id="index-completion_002dmap_002dcase"></a><span><code class="code">completion-map-case</code><a class="copiable-link" href="#index-completion_002dmap_002dcase"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, and <var class="var">completion-ignore-case</var> is enabled, Readline
+treats hyphens (‘<samp class="samp">-</samp>’) and underscores (‘<samp class="samp">_</samp>’) as equivalent when
performing case-insensitive filename matching and completion.
-The default value is ‘<samp>off</samp>’.
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-completion_002dprefix_002ddisplay_002dlength'><span><code>completion-prefix-display-length</code><a href='#index-completion_002dprefix_002ddisplay_002dlength' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-completion_002dprefix_002ddisplay_002dlength"></a><span><code class="code">completion-prefix-display-length</code><a class="copiable-link" href="#index-completion_002dprefix_002ddisplay_002dlength"> ¶</a></span></dt>
<dd><p>The length in characters of the common prefix of a list of possible
completions that is displayed without modification. When set to a
value greater than zero, common prefixes longer than this value are
replaced with an ellipsis when displaying possible completions.
</p>
</dd>
-<dt id='index-completion_002dquery_002ditems'><span><code>completion-query-items</code><a href='#index-completion_002dquery_002ditems' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-completion_002dquery_002ditems"></a><span><code class="code">completion-query-items</code><a class="copiable-link" href="#index-completion_002dquery_002ditems"> ¶</a></span></dt>
<dd><p>The number of possible completions that determines when the user is
asked whether the list of possibilities should be displayed.
If the number of possible completions is greater than or equal to this value,
This variable must be set to an integer value greater than or equal to zero.
A zero value means Readline should never ask; negative values are
treated as zero.
-The default limit is <code>100</code>.
+The default limit is <code class="code">100</code>.
</p>
</dd>
-<dt id='index-convert_002dmeta'><span><code>convert-meta</code><a href='#index-convert_002dmeta' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline will convert characters with the
-eighth bit set to an <small>ASCII</small> key sequence by stripping the eighth
-bit and prefixing an <tt class="key">ESC</tt> character, converting them to a
+<dt><a id="index-convert_002dmeta"></a><span><code class="code">convert-meta</code><a class="copiable-link" href="#index-convert_002dmeta"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline will convert characters with the
+eighth bit set to an <small class="sc">ASCII</small> key sequence by stripping the eighth
+bit and prefixing an <kbd class="key">ESC</kbd> character, converting them to a
meta-prefixed key sequence.
-The default value is ‘<samp>on</samp>’, but
-will be set to ‘<samp>off</samp>’ if the locale is one that contains
+The default value is ‘<samp class="samp">on</samp>’, but
+will be set to ‘<samp class="samp">off</samp>’ if the locale is one that contains
eight-bit characters.
-This variable is dependent on the <code>LC_CTYPE</code> locale category, and
+This variable is dependent on the <code class="code">LC_CTYPE</code> locale category, and
may change if the locale is changed.
</p>
</dd>
-<dt id='index-disable_002dcompletion'><span><code>disable-completion</code><a href='#index-disable_002dcompletion' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>On</samp>’, Readline will inhibit word completion.
+<dt><a id="index-disable_002dcompletion"></a><span><code class="code">disable-completion</code><a class="copiable-link" href="#index-disable_002dcompletion"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">On</samp>’, Readline will inhibit word completion.
Completion characters will be inserted into the line as if they had
-been mapped to <code>self-insert</code>. The default is ‘<samp>off</samp>’.
+been mapped to <code class="code">self-insert</code>. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-echo_002dcontrol_002dcharacters'><span><code>echo-control-characters</code><a href='#index-echo_002dcontrol_002dcharacters' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>When set to ‘<samp>on</samp>’, on operating systems that indicate they support it,
+<dt><a id="index-echo_002dcontrol_002dcharacters"></a><span><code class="code">echo-control-characters</code><a class="copiable-link" href="#index-echo_002dcontrol_002dcharacters"> ¶</a></span></dt>
+<dd><p>When set to ‘<samp class="samp">on</samp>’, on operating systems that indicate they support it,
Readline echoes a character corresponding to a signal generated from the
-keyboard. The default is ‘<samp>on</samp>’.
+keyboard. The default is ‘<samp class="samp">on</samp>’.
</p>
</dd>
-<dt id='index-editing_002dmode'><span><code>editing-mode</code><a href='#index-editing_002dmode' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The <code>editing-mode</code> variable controls which default set of
+<dt><a id="index-editing_002dmode"></a><span><code class="code">editing-mode</code><a class="copiable-link" href="#index-editing_002dmode"> ¶</a></span></dt>
+<dd><p>The <code class="code">editing-mode</code> variable controls which default set of
key bindings is used. By default, Readline starts up in Emacs editing
mode, where the keystrokes are most similar to Emacs. This variable can be
-set to either ‘<samp>emacs</samp>’ or ‘<samp>vi</samp>’.
+set to either ‘<samp class="samp">emacs</samp>’ or ‘<samp class="samp">vi</samp>’.
</p>
</dd>
-<dt id='index-emacs_002dmode_002dstring'><span><code>emacs-mode-string</code><a href='#index-emacs_002dmode_002dstring' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If the <var>show-mode-in-prompt</var> variable is enabled,
+<dt><a id="index-emacs_002dmode_002dstring"></a><span><code class="code">emacs-mode-string</code><a class="copiable-link" href="#index-emacs_002dmode_002dstring"> ¶</a></span></dt>
+<dd><p>If the <var class="var">show-mode-in-prompt</var> variable is enabled,
this string is displayed immediately before the last line of the primary
prompt when emacs editing mode is active. The value is expanded like a
key binding, so the standard set of meta- and control prefixes and
backslash escape sequences is available.
-Use the ‘<samp>\1</samp>’ and ‘<samp>\2</samp>’ escapes to begin and end sequences of
+Use the ‘<samp class="samp">\1</samp>’ and ‘<samp class="samp">\2</samp>’ escapes to begin and end sequences of
non-printing characters, which can be used to embed a terminal control
sequence into the mode string.
-The default is ‘<samp>@</samp>’.
+The default is ‘<samp class="samp">@</samp>’.
</p>
</dd>
-<dt id='index-enable_002dactive_002dregion'><span><code>enable-active-region</code><a href='#index-enable_002dactive_002dregion' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>The <em>point</em> is the current cursor position, and <em>mark</em> refers
-to a saved cursor position (see <a href="#Commands-For-Moving">Commands For Moving</a>).
-The text between the point and mark is referred to as the <em>region</em>.
-When this variable is set to ‘<samp>On</samp>’, Readline allows certain commands
-to designate the region as <em>active</em>.
+<dt><a id="index-enable_002dactive_002dregion"></a><span><code class="code">enable-active-region</code><a class="copiable-link" href="#index-enable_002dactive_002dregion"> ¶</a></span></dt>
+<dd><p>The <em class="dfn">point</em> is the current cursor position, and <em class="dfn">mark</em> refers
+to a saved cursor position (see <a class="pxref" href="#Commands-For-Moving">Commands For Moving</a>).
+The text between the point and mark is referred to as the <em class="dfn">region</em>.
+When this variable is set to ‘<samp class="samp">On</samp>’, Readline allows certain commands
+to designate the region as <em class="dfn">active</em>.
When the region is active, Readline highlights the text in the region using
-the value of the <code>active-region-start-color</code>, which defaults to the
+the value of the <code class="code">active-region-start-color</code>, which defaults to the
string that enables
the terminal’s standout mode.
The active region shows the text inserted by bracketed-paste and any
matching text found by incremental and non-incremental history searches.
-The default is ‘<samp>On</samp>’.
+The default is ‘<samp class="samp">On</samp>’.
</p>
</dd>
-<dt id='index-enable_002dbracketed_002dpaste'><span><code>enable-bracketed-paste</code><a href='#index-enable_002dbracketed_002dpaste' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>When set to ‘<samp>On</samp>’, Readline configures the terminal to insert each
+<dt><a id="index-enable_002dbracketed_002dpaste"></a><span><code class="code">enable-bracketed-paste</code><a class="copiable-link" href="#index-enable_002dbracketed_002dpaste"> ¶</a></span></dt>
+<dd><p>When set to ‘<samp class="samp">On</samp>’, Readline configures the terminal to insert each
paste into the editing buffer as a single string of characters, instead
of treating each character as if it had been read from the keyboard.
-This is called putting the terminal into <em>bracketed paste mode</em>;
+This is called putting the terminal into <em class="dfn">bracketed paste mode</em>;
it prevents Readline from executing any editing commands bound to key
sequences appearing in the pasted text.
-The default is ‘<samp>On</samp>’.
+The default is ‘<samp class="samp">On</samp>’.
</p>
</dd>
-<dt id='index-enable_002dkeypad'><span><code>enable-keypad</code><a href='#index-enable_002dkeypad' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>When set to ‘<samp>on</samp>’, Readline will try to enable the application
+<dt><a id="index-enable_002dkeypad"></a><span><code class="code">enable-keypad</code><a class="copiable-link" href="#index-enable_002dkeypad"> ¶</a></span></dt>
+<dd><p>When set to ‘<samp class="samp">on</samp>’, Readline will try to enable the application
keypad when it is called. Some systems need this to enable the
-arrow keys. The default is ‘<samp>off</samp>’.
+arrow keys. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt><span><code>enable-meta-key</code></span></dt>
-<dd><p>When set to ‘<samp>on</samp>’, Readline will try to enable any meta modifier
+<dt><code class="code">enable-meta-key</code></dt>
+<dd><p>When set to ‘<samp class="samp">on</samp>’, Readline will try to enable any meta modifier
key the terminal claims to support when it is called. On many terminals,
the meta key is used to send eight-bit characters.
-The default is ‘<samp>on</samp>’.
+The default is ‘<samp class="samp">on</samp>’.
</p>
</dd>
-<dt id='index-expand_002dtilde'><span><code>expand-tilde</code><a href='#index-expand_002dtilde' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, tilde expansion is performed when Readline
-attempts word completion. The default is ‘<samp>off</samp>’.
+<dt><a id="index-expand_002dtilde"></a><span><code class="code">expand-tilde</code><a class="copiable-link" href="#index-expand_002dtilde"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, tilde expansion is performed when Readline
+attempts word completion. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-history_002dpreserve_002dpoint'><span><code>history-preserve-point</code><a href='#index-history_002dpreserve_002dpoint' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, the history code attempts to place the point (the
+<dt><a id="index-history_002dpreserve_002dpoint"></a><span><code class="code">history-preserve-point</code><a class="copiable-link" href="#index-history_002dpreserve_002dpoint"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, the history code attempts to place the point (the
current cursor position) at the
-same location on each history line retrieved with <code>previous-history</code>
-or <code>next-history</code>. The default is ‘<samp>off</samp>’.
+same location on each history line retrieved with <code class="code">previous-history</code>
+or <code class="code">next-history</code>. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-history_002dsize'><span><code>history-size</code><a href='#index-history_002dsize' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dsize"></a><span><code class="code">history-size</code><a class="copiable-link" href="#index-history_002dsize"> ¶</a></span></dt>
<dd><p>Set the maximum number of history entries saved in the history list.
If set to zero, any existing history entries are deleted and no new entries
are saved.
If set to a value less than zero, the number of history entries is not
limited.
By default, the number of history entries is not limited.
-If an attempt is made to set <var>history-size</var> to a non-numeric value,
+If an attempt is made to set <var class="var">history-size</var> to a non-numeric value,
the maximum number of history entries will be set to 500.
</p>
</dd>
-<dt id='index-horizontal_002dscroll_002dmode'><span><code>horizontal-scroll-mode</code><a href='#index-horizontal_002dscroll_002dmode' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>This variable can be set to either ‘<samp>on</samp>’ or ‘<samp>off</samp>’. Setting it
-to ‘<samp>on</samp>’ means that the text of the lines being edited will scroll
+<dt><a id="index-horizontal_002dscroll_002dmode"></a><span><code class="code">horizontal-scroll-mode</code><a class="copiable-link" href="#index-horizontal_002dscroll_002dmode"> ¶</a></span></dt>
+<dd><p>This variable can be set to either ‘<samp class="samp">on</samp>’ or ‘<samp class="samp">off</samp>’. Setting it
+to ‘<samp class="samp">on</samp>’ means that the text of the lines being edited will scroll
horizontally on a single screen line when they are longer than the width
of the screen, instead of wrapping onto a new screen line.
-This variable is automatically set to ‘<samp>on</samp>’ for terminals of height 1.
-By default, this variable is set to ‘<samp>off</samp>’.
+This variable is automatically set to ‘<samp class="samp">on</samp>’ for terminals of height 1.
+By default, this variable is set to ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-input_002dmeta'><span><code>input-meta</code><a href='#index-input_002dmeta' class='copiable-anchor'> ¶</a></span></dt>
-<dd><span id="index-meta_002dflag"></span>
-<p>If set to ‘<samp>on</samp>’, Readline will enable eight-bit input (it
+<dt><a class="index-entry-id" id="index-meta_002dflag"></a>
+<a id="index-input_002dmeta"></a><span><code class="code">input-meta</code><a class="copiable-link" href="#index-input_002dmeta"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline will enable eight-bit input (it
will not clear the eighth bit in the characters it reads),
regardless of what the terminal claims it can support. The
-default value is ‘<samp>off</samp>’, but Readline will set it to ‘<samp>on</samp>’ if the
+default value is ‘<samp class="samp">off</samp>’, but Readline will set it to ‘<samp class="samp">on</samp>’ if the
locale contains eight-bit characters.
-The name <code>meta-flag</code> is a synonym for this variable.
-This variable is dependent on the <code>LC_CTYPE</code> locale category, and
+The name <code class="code">meta-flag</code> is a synonym for this variable.
+This variable is dependent on the <code class="code">LC_CTYPE</code> locale category, and
may change if the locale is changed.
</p>
</dd>
-<dt id='index-isearch_002dterminators'><span><code>isearch-terminators</code><a href='#index-isearch_002dterminators' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-isearch_002dterminators"></a><span><code class="code">isearch-terminators</code><a class="copiable-link" href="#index-isearch_002dterminators"> ¶</a></span></dt>
<dd><p>The string of characters that should terminate an incremental search without
-subsequently executing the character as a command (see <a href="#Searching">Searching for Commands in the History</a>).
-If this variable has not been given a value, the characters <tt class="key">ESC</tt> and
-<kbd>C-J</kbd> will terminate an incremental search.
+subsequently executing the character as a command (see <a class="pxref" href="#Searching">Searching for Commands in the History</a>).
+If this variable has not been given a value, the characters <kbd class="key">ESC</kbd> and
+<kbd class="kbd">C-J</kbd> will terminate an incremental search.
</p>
</dd>
-<dt id='index-keymap'><span><code>keymap</code><a href='#index-keymap' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-keymap"></a><span><code class="code">keymap</code><a class="copiable-link" href="#index-keymap"> ¶</a></span></dt>
<dd><p>Sets Readline’s idea of the current keymap for key binding commands.
-Built-in <code>keymap</code> names are
-<code>emacs</code>,
-<code>emacs-standard</code>,
-<code>emacs-meta</code>,
-<code>emacs-ctlx</code>,
-<code>vi</code>,
-<code>vi-move</code>,
-<code>vi-command</code>, and
-<code>vi-insert</code>.
-<code>vi</code> is equivalent to <code>vi-command</code> (<code>vi-move</code> is also a
-synonym); <code>emacs</code> is equivalent to <code>emacs-standard</code>.
+Built-in <code class="code">keymap</code> names are
+<code class="code">emacs</code>,
+<code class="code">emacs-standard</code>,
+<code class="code">emacs-meta</code>,
+<code class="code">emacs-ctlx</code>,
+<code class="code">vi</code>,
+<code class="code">vi-move</code>,
+<code class="code">vi-command</code>, and
+<code class="code">vi-insert</code>.
+<code class="code">vi</code> is equivalent to <code class="code">vi-command</code> (<code class="code">vi-move</code> is also a
+synonym); <code class="code">emacs</code> is equivalent to <code class="code">emacs-standard</code>.
Applications may add additional names.
-The default value is <code>emacs</code>.
-The value of the <code>editing-mode</code> variable also affects the
+The default value is <code class="code">emacs</code>.
+The value of the <code class="code">editing-mode</code> variable also affects the
default keymap.
</p>
</dd>
-<dt><span><code>keyseq-timeout</code></span></dt>
+<dt><code class="code">keyseq-timeout</code></dt>
<dd><p>Specifies the duration Readline will wait for a character when reading an
ambiguous key sequence (one that can form a complete key sequence using
the input read so far, or can take additional input to complete a longer
If no input is received within the timeout, Readline will use the shorter
but complete key sequence.
Readline uses this value to determine whether or not input is
-available on the current input source (<code>rl_instream</code> by default).
+available on the current input source (<code class="code">rl_instream</code> by default).
The value is specified in milliseconds, so a value of 1000 means that
Readline will wait one second for additional input.
If this variable is set to a value less than or equal to zero, or to a
non-numeric value, Readline will wait until another key is pressed to
decide which key sequence to complete.
-The default value is <code>500</code>.
+The default value is <code class="code">500</code>.
</p>
</dd>
-<dt><span><code>mark-directories</code></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, completed directory names have a slash
-appended. The default is ‘<samp>on</samp>’.
+<dt><code class="code">mark-directories</code></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, completed directory names have a slash
+appended. The default is ‘<samp class="samp">on</samp>’.
</p>
</dd>
-<dt id='index-mark_002dmodified_002dlines'><span><code>mark-modified-lines</code><a href='#index-mark_002dmodified_002dlines' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>This variable, when set to ‘<samp>on</samp>’, causes Readline to display an
-asterisk (‘<samp>*</samp>’) at the start of history lines which have been modified.
-This variable is ‘<samp>off</samp>’ by default.
+<dt><a id="index-mark_002dmodified_002dlines"></a><span><code class="code">mark-modified-lines</code><a class="copiable-link" href="#index-mark_002dmodified_002dlines"> ¶</a></span></dt>
+<dd><p>This variable, when set to ‘<samp class="samp">on</samp>’, causes Readline to display an
+asterisk (‘<samp class="samp">*</samp>’) at the start of history lines which have been modified.
+This variable is ‘<samp class="samp">off</samp>’ by default.
</p>
</dd>
-<dt id='index-mark_002dsymlinked_002ddirectories'><span><code>mark-symlinked-directories</code><a href='#index-mark_002dsymlinked_002ddirectories' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, completed names which are symbolic links
+<dt><a id="index-mark_002dsymlinked_002ddirectories"></a><span><code class="code">mark-symlinked-directories</code><a class="copiable-link" href="#index-mark_002dsymlinked_002ddirectories"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, completed names which are symbolic links
to directories have a slash appended (subject to the value of
-<code>mark-directories</code>).
-The default is ‘<samp>off</samp>’.
+<code class="code">mark-directories</code>).
+The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-match_002dhidden_002dfiles'><span><code>match-hidden-files</code><a href='#index-match_002dhidden_002dfiles' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>This variable, when set to ‘<samp>on</samp>’, causes Readline to match files whose
-names begin with a ‘<samp>.</samp>’ (hidden files) when performing filename
+<dt><a id="index-match_002dhidden_002dfiles"></a><span><code class="code">match-hidden-files</code><a class="copiable-link" href="#index-match_002dhidden_002dfiles"> ¶</a></span></dt>
+<dd><p>This variable, when set to ‘<samp class="samp">on</samp>’, forces Readline to match files whose
+names begin with a ‘<samp class="samp">.</samp>’ (hidden files) when performing filename
completion.
-If set to ‘<samp>off</samp>’, the leading ‘<samp>.</samp>’ must be
-supplied by the user in the filename to be completed.
-This variable is ‘<samp>on</samp>’ by default.
+If set to ‘<samp class="samp">off</samp>’, the user must include the leading ‘<samp class="samp">.</samp>’
+in the filename to be completed.
+This variable is ‘<samp class="samp">on</samp>’ by default.
</p>
</dd>
-<dt id='index-menu_002dcomplete_002ddisplay_002dprefix'><span><code>menu-complete-display-prefix</code><a href='#index-menu_002dcomplete_002ddisplay_002dprefix' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, menu completion displays the common prefix of the
+<dt><a id="index-menu_002dcomplete_002ddisplay_002dprefix"></a><span><code class="code">menu-complete-display-prefix</code><a class="copiable-link" href="#index-menu_002dcomplete_002ddisplay_002dprefix"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, menu completion displays the common prefix of the
list of possible completions (which may be empty) before cycling through
-the list. The default is ‘<samp>off</samp>’.
+the list. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-output_002dmeta'><span><code>output-meta</code><a href='#index-output_002dmeta' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline will display characters with the
+<dt><a id="index-output_002dmeta"></a><span><code class="code">output-meta</code><a class="copiable-link" href="#index-output_002dmeta"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline will display characters with the
eighth bit set directly rather than as a meta-prefixed escape
sequence.
-The default is ‘<samp>off</samp>’, but Readline will set it to ‘<samp>on</samp>’ if the
+The default is ‘<samp class="samp">off</samp>’, but Readline will set it to ‘<samp class="samp">on</samp>’ if the
locale contains eight-bit characters.
-This variable is dependent on the <code>LC_CTYPE</code> locale category, and
+This variable is dependent on the <code class="code">LC_CTYPE</code> locale category, and
may change if the locale is changed.
</p>
</dd>
-<dt id='index-page_002dcompletions'><span><code>page-completions</code><a href='#index-page_002dcompletions' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline uses an internal <code>more</code>-like pager
+<dt><a id="index-page_002dcompletions"></a><span><code class="code">page-completions</code><a class="copiable-link" href="#index-page_002dcompletions"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline uses an internal <code class="code">more</code>-like pager
to display a screenful of possible completions at a time.
-This variable is ‘<samp>on</samp>’ by default.
+This variable is ‘<samp class="samp">on</samp>’ by default.
</p>
</dd>
-<dt><span><code>print-completions-horizontally</code></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline will display completions with matches
+<dt><code class="code">print-completions-horizontally</code></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline will display completions with matches
sorted horizontally in alphabetical order, rather than down the screen.
-The default is ‘<samp>off</samp>’.
+The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-revert_002dall_002dat_002dnewline'><span><code>revert-all-at-newline</code><a href='#index-revert_002dall_002dat_002dnewline' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline will undo all changes to history lines
-before returning when <code>accept-line</code> is executed. By default,
+<dt><a id="index-revert_002dall_002dat_002dnewline"></a><span><code class="code">revert-all-at-newline</code><a class="copiable-link" href="#index-revert_002dall_002dat_002dnewline"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline will undo all changes to history lines
+before returning when <code class="code">accept-line</code> is executed. By default,
history lines may be modified and retain individual undo lists across
-calls to <code>readline()</code>. The default is ‘<samp>off</samp>’.
+calls to <code class="code">readline()</code>. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-search_002dignore_002dcase'><span><code>search-ignore-case</code><a href='#index-search_002dignore_002dcase' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, Readline performs incremental and non-incremental
+<dt><a id="index-search_002dignore_002dcase"></a><span><code class="code">search-ignore-case</code><a class="copiable-link" href="#index-search_002dignore_002dcase"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, Readline performs incremental and non-incremental
history list searches in a case-insensitive fashion.
-The default value is ‘<samp>off</samp>’.
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-show_002dall_002dif_002dambiguous'><span><code>show-all-if-ambiguous</code><a href='#index-show_002dall_002dif_002dambiguous' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-show_002dall_002dif_002dambiguous"></a><span><code class="code">show-all-if-ambiguous</code><a class="copiable-link" href="#index-show_002dall_002dif_002dambiguous"> ¶</a></span></dt>
<dd><p>This alters the default behavior of the completion functions. If
-set to ‘<samp>on</samp>’,
+set to ‘<samp class="samp">on</samp>’,
words which have more than one possible completion cause the
matches to be listed immediately instead of ringing the bell.
-The default value is ‘<samp>off</samp>’.
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-show_002dall_002dif_002dunmodified'><span><code>show-all-if-unmodified</code><a href='#index-show_002dall_002dif_002dunmodified' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-show_002dall_002dif_002dunmodified"></a><span><code class="code">show-all-if-unmodified</code><a class="copiable-link" href="#index-show_002dall_002dif_002dunmodified"> ¶</a></span></dt>
<dd><p>This alters the default behavior of the completion functions in
-a fashion similar to <var>show-all-if-ambiguous</var>.
-If set to ‘<samp>on</samp>’,
+a fashion similar to <var class="var">show-all-if-ambiguous</var>.
+If set to ‘<samp class="samp">on</samp>’,
words which have more than one possible completion without any
possible partial completion (the possible completions don’t share
a common prefix) cause the matches to be listed immediately instead
of ringing the bell.
-The default value is ‘<samp>off</samp>’.
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-show_002dmode_002din_002dprompt'><span><code>show-mode-in-prompt</code><a href='#index-show_002dmode_002din_002dprompt' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, add a string to the beginning of the prompt
+<dt><a id="index-show_002dmode_002din_002dprompt"></a><span><code class="code">show-mode-in-prompt</code><a class="copiable-link" href="#index-show_002dmode_002din_002dprompt"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, add a string to the beginning of the prompt
indicating the editing mode: emacs, vi command, or vi insertion.
-The mode strings are user-settable (e.g., <var>emacs-mode-string</var>).
-The default value is ‘<samp>off</samp>’.
+The mode strings are user-settable (e.g., <var class="var">emacs-mode-string</var>).
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-skip_002dcompleted_002dtext'><span><code>skip-completed-text</code><a href='#index-skip_002dcompleted_002dtext' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, this alters the default completion behavior when
+<dt><a id="index-skip_002dcompleted_002dtext"></a><span><code class="code">skip-completed-text</code><a class="copiable-link" href="#index-skip_002dcompleted_002dtext"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, this alters the default completion behavior when
inserting a single match into the line. It’s only active when
performing completion in the middle of a word. If enabled, Readline
does not insert characters from the completion that match characters
after point in the word being completed, so portions of the word
following the cursor are not duplicated.
For instance, if this is enabled, attempting completion when the cursor
-is after the ‘<samp>e</samp>’ in ‘<samp>Makefile</samp>’ will result in ‘<samp>Makefile</samp>’
-rather than ‘<samp>Makefilefile</samp>’, assuming there is a single possible
+is after the ‘<samp class="samp">e</samp>’ in ‘<samp class="samp">Makefile</samp>’ will result in ‘<samp class="samp">Makefile</samp>’
+rather than ‘<samp class="samp">Makefilefile</samp>’, assuming there is a single possible
completion.
-The default value is ‘<samp>off</samp>’.
+The default value is ‘<samp class="samp">off</samp>’.
</p>
</dd>
-<dt id='index-vi_002dcmd_002dmode_002dstring'><span><code>vi-cmd-mode-string</code><a href='#index-vi_002dcmd_002dmode_002dstring' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If the <var>show-mode-in-prompt</var> variable is enabled,
+<dt><a id="index-vi_002dcmd_002dmode_002dstring"></a><span><code class="code">vi-cmd-mode-string</code><a class="copiable-link" href="#index-vi_002dcmd_002dmode_002dstring"> ¶</a></span></dt>
+<dd><p>If the <var class="var">show-mode-in-prompt</var> variable is enabled,
this string is displayed immediately before the last line of the primary
prompt when vi editing mode is active and in command mode.
The value is expanded like a
key binding, so the standard set of meta- and control prefixes and
backslash escape sequences is available.
-Use the ‘<samp>\1</samp>’ and ‘<samp>\2</samp>’ escapes to begin and end sequences of
+Use the ‘<samp class="samp">\1</samp>’ and ‘<samp class="samp">\2</samp>’ escapes to begin and end sequences of
non-printing characters, which can be used to embed a terminal control
sequence into the mode string.
-The default is ‘<samp>(cmd)</samp>’.
+The default is ‘<samp class="samp">(cmd)</samp>’.
</p>
</dd>
-<dt id='index-vi_002dins_002dmode_002dstring'><span><code>vi-ins-mode-string</code><a href='#index-vi_002dins_002dmode_002dstring' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If the <var>show-mode-in-prompt</var> variable is enabled,
+<dt><a id="index-vi_002dins_002dmode_002dstring"></a><span><code class="code">vi-ins-mode-string</code><a class="copiable-link" href="#index-vi_002dins_002dmode_002dstring"> ¶</a></span></dt>
+<dd><p>If the <var class="var">show-mode-in-prompt</var> variable is enabled,
this string is displayed immediately before the last line of the primary
prompt when vi editing mode is active and in insertion mode.
The value is expanded like a
key binding, so the standard set of meta- and control prefixes and
backslash escape sequences is available.
-Use the ‘<samp>\1</samp>’ and ‘<samp>\2</samp>’ escapes to begin and end sequences of
+Use the ‘<samp class="samp">\1</samp>’ and ‘<samp class="samp">\2</samp>’ escapes to begin and end sequences of
non-printing characters, which can be used to embed a terminal control
sequence into the mode string.
-The default is ‘<samp>(ins)</samp>’.
+The default is ‘<samp class="samp">(ins)</samp>’.
</p>
</dd>
-<dt id='index-visible_002dstats'><span><code>visible-stats</code><a href='#index-visible_002dstats' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If set to ‘<samp>on</samp>’, a character denoting a file’s type
+<dt><a id="index-visible_002dstats"></a><span><code class="code">visible-stats</code><a class="copiable-link" href="#index-visible_002dstats"> ¶</a></span></dt>
+<dd><p>If set to ‘<samp class="samp">on</samp>’, a character denoting a file’s type
is appended to the filename when listing possible
-completions. The default is ‘<samp>off</samp>’.
+completions. The default is ‘<samp class="samp">off</samp>’.
</p>
</dd>
</dl>
</dd>
-<dt><span>Key Bindings</span></dt>
+<dt>Key Bindings</dt>
<dd><p>The syntax for controlling key bindings in the init file is
simple. First you need to find the name of the command that you
want to change. The following sections contain tables of the command
what you find most comfortable.
</p>
<p>In addition to command names, Readline allows keys to be bound
-to a string that is inserted when the key is pressed (a <var>macro</var>).
+to a string that is inserted when the key is pressed (a <var class="var">macro</var>).
</p>
-<p>The <code>bind <span class="nolinebreak">-p</span></code><!-- /@w --> command displays Readline function names and
+<p>The <code class="code">bind -p</code><!-- /@w --> command displays Readline function names and
bindings in a format that can be put directly into an initialization file.
-See <a href="#Bash-Builtins">Bash Builtin Commands</a>.
+See <a class="xref" href="#Bash-Builtins">Bash Builtin Commands</a>.
</p>
-<dl compact="compact">
-<dt><span><var>keyname</var>: <var><span class="nolinebreak">function-name</span></var> or <var>macro</var><!-- /@w --></span></dt>
-<dd><p><var>keyname</var> is the name of a key spelled out in English. For example:
+<dl class="table">
+<dt><var class="var">keyname</var>: <var class="var">function-name</var> or <var class="var">macro</var><!-- /@w --></dt>
+<dd><p><var class="var">keyname</var> is the name of a key spelled out in English. For example:
</p><div class="example">
-<pre class="example">Control-u: universal-argument
+<pre class="example-preformatted">Control-u: universal-argument
Meta-Rubout: backward-kill-word
Control-o: "> output"
</pre></div>
-<p>In the example above, <kbd>C-u</kbd> is bound to the function
-<code>universal-argument</code>,
-<kbd>M-DEL</kbd> is bound to the function <code>backward-kill-word</code>, and
-<kbd>C-o</kbd> is bound to run the macro
+<p>In the example above, <kbd class="kbd">C-u</kbd> is bound to the function
+<code class="code">universal-argument</code>,
+<kbd class="kbd">M-DEL</kbd> is bound to the function <code class="code">backward-kill-word</code>, and
+<kbd class="kbd">C-o</kbd> is bound to run the macro
expressed on the right hand side (that is, to insert the text
-‘<samp>> output</samp>’ into the line).
+‘<samp class="samp">> output</samp>’ into the line).
</p>
<p>A number of symbolic character names are recognized while
processing this key binding syntax:
-<var>DEL</var>,
-<var>ESC</var>,
-<var>ESCAPE</var>,
-<var>LFD</var>,
-<var>NEWLINE</var>,
-<var>RET</var>,
-<var>RETURN</var>,
-<var>RUBOUT</var>,
-<var>SPACE</var>,
-<var>SPC</var>,
+<var class="var">DEL</var>,
+<var class="var">ESC</var>,
+<var class="var">ESCAPE</var>,
+<var class="var">LFD</var>,
+<var class="var">NEWLINE</var>,
+<var class="var">RET</var>,
+<var class="var">RETURN</var>,
+<var class="var">RUBOUT</var>,
+<var class="var">SPACE</var>,
+<var class="var">SPC</var>,
and
-<var>TAB</var>.
+<var class="var">TAB</var>.
</p>
</dd>
-<dt><span>"<var>keyseq</var>": <var><span class="nolinebreak">function-name</span></var> or <var>macro</var><!-- /@w --></span></dt>
-<dd><p><var>keyseq</var> differs from <var>keyname</var> above in that strings
+<dt>"<var class="var">keyseq</var>": <var class="var">function-name</var> or <var class="var">macro</var><!-- /@w --></dt>
+<dd><p><var class="var">keyseq</var> differs from <var class="var">keyname</var> above in that strings
denoting an entire key sequence can be specified, by placing
-the key sequence in double quotes. Some <small>GNU</small> Emacs style key
+the key sequence in double quotes. Some <small class="sc">GNU</small> Emacs style key
escapes can be used, as in the following example, but the
special character names are not recognized.
</p>
<div class="example">
-<pre class="example">"\C-u": universal-argument
+<pre class="example-preformatted">"\C-u": universal-argument
"\C-x\C-r": re-read-init-file
"\e[11~": "Function Key 1"
</pre></div>
-<p>In the above example, <kbd>C-u</kbd> is again bound to the function
-<code>universal-argument</code> (just as it was in the first example),
-‘<samp><kbd>C-x</kbd> <kbd>C-r</kbd></samp>’ is bound to the function <code>re-read-init-file</code>,
-and ‘<samp><span class="key">ESC</span> <span class="key">[</span> <span class="key">1</span> <span class="key">1</span> <span class="key">~</span></samp>’ is bound to insert
-the text ‘<samp>Function Key 1</samp>’.
+<p>In the above example, <kbd class="kbd">C-u</kbd> is again bound to the function
+<code class="code">universal-argument</code> (just as it was in the first example),
+‘<samp class="samp"><kbd class="kbd">C-x</kbd> <kbd class="kbd">C-r</kbd></samp>’ is bound to the function <code class="code">re-read-init-file</code>,
+and ‘<samp class="samp"><kbd class="key">ESC</kbd> <kbd class="key">[</kbd> <kbd class="key">1</kbd> <kbd class="key">1</kbd> <kbd class="key">~</kbd></samp>’ is bound to insert
+the text ‘<samp class="samp">Function Key 1</samp>’.
</p>
</dd>
</dl>
-<p>The following <small>GNU</small> Emacs style escape sequences are available when
+<p>The following <small class="sc">GNU</small> Emacs style escape sequences are available when
specifying key sequences:
</p>
-<dl compact="compact">
-<dt><span><code><kbd>\C-</kbd></code></span></dt>
+<dl class="table">
+<dt><code class="code"><kbd class="kbd">\C-</kbd></code></dt>
<dd><p>control prefix
</p></dd>
-<dt><span><code><kbd>\M-</kbd></code></span></dt>
+<dt><code class="code"><kbd class="kbd">\M-</kbd></code></dt>
<dd><p>meta prefix
</p></dd>
-<dt><span><code><kbd>\e</kbd></code></span></dt>
+<dt><code class="code"><kbd class="kbd">\e</kbd></code></dt>
<dd><p>an escape character
</p></dd>
-<dt><span><code><kbd>\\</kbd></code></span></dt>
+<dt><code class="code"><kbd class="kbd">\\</kbd></code></dt>
<dd><p>backslash
</p></dd>
-<dt><span><code><kbd>\"</kbd></code></span></dt>
-<dd><p><tt class="key">"</tt>, a double quotation mark
+<dt><code class="code"><kbd class="kbd">\"</kbd></code></dt>
+<dd><p><kbd class="key">"</kbd>, a double quotation mark
</p></dd>
-<dt><span><code><kbd>\'</kbd></code></span></dt>
-<dd><p><tt class="key">'</tt>, a single quote or apostrophe
+<dt><code class="code"><kbd class="kbd">\'</kbd></code></dt>
+<dd><p><kbd class="key">'</kbd>, a single quote or apostrophe
</p></dd>
</dl>
-<p>In addition to the <small>GNU</small> Emacs style escape sequences, a second
+<p>In addition to the <small class="sc">GNU</small> Emacs style escape sequences, a second
set of backslash escapes is available:
</p>
-<dl compact="compact">
-<dt><span><code>\a</code></span></dt>
+<dl class="table">
+<dt><code class="code">\a</code></dt>
<dd><p>alert (bell)
</p></dd>
-<dt><span><code>\b</code></span></dt>
+<dt><code class="code">\b</code></dt>
<dd><p>backspace
</p></dd>
-<dt><span><code>\d</code></span></dt>
+<dt><code class="code">\d</code></dt>
<dd><p>delete
</p></dd>
-<dt><span><code>\f</code></span></dt>
+<dt><code class="code">\f</code></dt>
<dd><p>form feed
</p></dd>
-<dt><span><code>\n</code></span></dt>
+<dt><code class="code">\n</code></dt>
<dd><p>newline
</p></dd>
-<dt><span><code>\r</code></span></dt>
+<dt><code class="code">\r</code></dt>
<dd><p>carriage return
</p></dd>
-<dt><span><code>\t</code></span></dt>
+<dt><code class="code">\t</code></dt>
<dd><p>horizontal tab
</p></dd>
-<dt><span><code>\v</code></span></dt>
+<dt><code class="code">\v</code></dt>
<dd><p>vertical tab
</p></dd>
-<dt><span><code>\<var>nnn</var></code></span></dt>
-<dd><p>the eight-bit character whose value is the octal value <var>nnn</var>
+<dt><code class="code">\<var class="var">nnn</var></code></dt>
+<dd><p>the eight-bit character whose value is the octal value <var class="var">nnn</var>
(one to three digits)
</p></dd>
-<dt><span><code>\x<var>HH</var></code></span></dt>
-<dd><p>the eight-bit character whose value is the hexadecimal value <var>HH</var>
+<dt><code class="code">\x<var class="var">HH</var></code></dt>
+<dd><p>the eight-bit character whose value is the hexadecimal value <var class="var">HH</var>
(one or two hex digits)
</p></dd>
</dl>
Unquoted text is assumed to be a function name.
In the macro body, the backslash escapes described above are expanded.
Backslash will quote any other character in the macro text,
-including ‘<samp>"</samp>’ and ‘<samp>'</samp>’.
-For example, the following binding will make ‘<samp><kbd>C-x</kbd> \</samp>’
-insert a single ‘<samp>\</samp>’ into the line:
+including ‘<samp class="samp">"</samp>’ and ‘<samp class="samp">'</samp>’.
+For example, the following binding will make ‘<samp class="samp"><kbd class="kbd">C-x</kbd> \</samp>’
+insert a single ‘<samp class="samp">\</samp>’ into the line:
</p><div class="example">
-<pre class="example">"\C-x\\": "\\"
+<pre class="example-preformatted">"\C-x\\": "\\"
</pre></div>
</dd>
<hr>
</div>
-<div class="subsection" id="Conditional-Init-Constructs">
-<div class="header">
+<div class="subsection-level-extent" id="Conditional-Init-Constructs">
+<div class="nav-panel">
<p>
Next: <a href="#Sample-Init-File" accesskey="n" rel="next">Sample Init File</a>, Previous: <a href="#Readline-Init-File-Syntax" accesskey="p" rel="prev">Readline Init File Syntax</a>, Up: <a href="#Readline-Init-File" accesskey="u" rel="up">Readline Init File</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Conditional-Init-Constructs-1"></span><h4 class="subsection">8.3.2 Conditional Init Constructs</h4>
+<h4 class="subsection" id="Conditional-Init-Constructs-1"><span>8.3.2 Conditional Init Constructs<a class="copiable-link" href="#Conditional-Init-Constructs-1"> ¶</a></span></h4>
<p>Readline implements a facility similar in spirit to the conditional
compilation features of the C preprocessor which allows key
bindings and variable settings to be performed as the result
of tests. There are four parser directives used.
</p>
-<dl compact="compact">
-<dt><span><code>$if</code></span></dt>
-<dd><p>The <code>$if</code> construct allows bindings to be made based on the
+<dl class="table">
+<dt><code class="code">$if</code></dt>
+<dd><p>The <code class="code">$if</code> construct allows bindings to be made based on the
editing mode, the terminal being used, or the application using
Readline. The text of the test, after any comparison operator,
extends to the end of the line;
unless otherwise noted, no characters are required to isolate it.
</p>
-<dl compact="compact">
-<dt><span><code>mode</code></span></dt>
-<dd><p>The <code>mode=</code> form of the <code>$if</code> directive is used to test
-whether Readline is in <code>emacs</code> or <code>vi</code> mode.
+<dl class="table">
+<dt><code class="code">mode</code></dt>
+<dd><p>The <code class="code">mode=</code> form of the <code class="code">$if</code> directive is used to test
+whether Readline is in <code class="code">emacs</code> or <code class="code">vi</code> mode.
This may be used in conjunction
-with the ‘<samp>set keymap</samp>’ command, for instance, to set bindings in
-the <code>emacs-standard</code> and <code>emacs-ctlx</code> keymaps only if
-Readline is starting out in <code>emacs</code> mode.
+with the ‘<samp class="samp">set keymap</samp>’ command, for instance, to set bindings in
+the <code class="code">emacs-standard</code> and <code class="code">emacs-ctlx</code> keymaps only if
+Readline is starting out in <code class="code">emacs</code> mode.
</p>
</dd>
-<dt><span><code>term</code></span></dt>
-<dd><p>The <code>term=</code> form may be used to include terminal-specific
+<dt><code class="code">term</code></dt>
+<dd><p>The <code class="code">term=</code> form may be used to include terminal-specific
key bindings, perhaps to bind the key sequences output by the
terminal’s function keys. The word on the right side of the
-‘<samp>=</samp>’ is tested against both the full name of the terminal and
-the portion of the terminal name before the first ‘<samp>-</samp>’. This
-allows <code>sun</code> to match both <code>sun</code> and <code>sun-cmd</code>,
+‘<samp class="samp">=</samp>’ is tested against both the full name of the terminal and
+the portion of the terminal name before the first ‘<samp class="samp">-</samp>’. This
+allows <code class="code">sun</code> to match both <code class="code">sun</code> and <code class="code">sun-cmd</code>,
for instance.
</p>
</dd>
-<dt><span><code>version</code></span></dt>
-<dd><p>The <code>version</code> test may be used to perform comparisons against
+<dt><code class="code">version</code></dt>
+<dd><p>The <code class="code">version</code> test may be used to perform comparisons against
specific Readline versions.
-The <code>version</code> expands to the current Readline version.
+The <code class="code">version</code> expands to the current Readline version.
The set of comparison operators includes
-‘<samp>=</samp>’ (and ‘<samp>==</samp>’), ‘<samp>!=</samp>’, ‘<samp><=</samp>’, ‘<samp>>=</samp>’, ‘<samp><</samp>’,
-and ‘<samp>></samp>’.
+‘<samp class="samp">=</samp>’ (and ‘<samp class="samp">==</samp>’), ‘<samp class="samp">!=</samp>’, ‘<samp class="samp"><=</samp>’, ‘<samp class="samp">>=</samp>’, ‘<samp class="samp"><</samp>’,
+and ‘<samp class="samp">></samp>’.
The version number supplied on the right side of the operator consists
of a major version number, an optional decimal point, and an optional
-minor version (e.g., ‘<samp>7.1</samp>’). If the minor version is omitted, it
-is assumed to be ‘<samp>0</samp>’.
-The operator may be separated from the string <code>version</code> and
+minor version (e.g., ‘<samp class="samp">7.1</samp>’). If the minor version is omitted, it
+is assumed to be ‘<samp class="samp">0</samp>’.
+The operator may be separated from the string <code class="code">version</code> and
from the version number argument by whitespace.
The following example sets a variable if the Readline version being used
is 7.0 or newer:
</p><div class="example">
-<pre class="example">$if version >= 7.0
+<pre class="example-preformatted">$if version >= 7.0
set show-mode-in-prompt on
$endif
</pre></div>
</dd>
-<dt><span><code>application</code></span></dt>
-<dd><p>The <var>application</var> construct is used to include
+<dt><code class="code">application</code></dt>
+<dd><p>The <var class="var">application</var> construct is used to include
application-specific settings. Each program using the Readline
-library sets the <var>application name</var>, and you can test for
+library sets the <var class="var">application name</var>, and you can test for
a particular value.
This could be used to bind key sequences to functions useful for
a specific program. For instance, the following command adds a
key sequence that quotes the current or previous word in Bash:
</p><div class="example">
-<pre class="example">$if Bash
+<pre class="example-preformatted">$if Bash
# Quote the current or previous word
"\C-xq": "\eb\"\ef\""
$endif
</pre></div>
</dd>
-<dt><span><code>variable</code></span></dt>
-<dd><p>The <var>variable</var> construct provides simple equality tests for Readline
+<dt><code class="code">variable</code></dt>
+<dd><p>The <var class="var">variable</var> construct provides simple equality tests for Readline
variables and values.
-The permitted comparison operators are ‘<samp>=</samp>’, ‘<samp>==</samp>’, and ‘<samp>!=</samp>’.
+The permitted comparison operators are ‘<samp class="samp">=</samp>’, ‘<samp class="samp">==</samp>’, and ‘<samp class="samp">!=</samp>’.
The variable name must be separated from the comparison operator by
whitespace; the operator may be separated from the value on the right hand
side by whitespace.
Both string and boolean variables may be tested. Boolean variables must be
-tested against the values <var>on</var> and <var>off</var>.
-The following example is equivalent to the <code>mode=emacs</code> test described
+tested against the values <var class="var">on</var> and <var class="var">off</var>.
+The following example is equivalent to the <code class="code">mode=emacs</code> test described
above:
</p><div class="example">
-<pre class="example">$if editing-mode == emacs
+<pre class="example-preformatted">$if editing-mode == emacs
set show-mode-in-prompt on
$endif
</pre></div>
</dl>
</dd>
-<dt><span><code>$endif</code></span></dt>
+<dt><code class="code">$endif</code></dt>
<dd><p>This command, as seen in the previous example, terminates an
-<code>$if</code> command.
+<code class="code">$if</code> command.
</p>
</dd>
-<dt><span><code>$else</code></span></dt>
-<dd><p>Commands in this branch of the <code>$if</code> directive are executed if
+<dt><code class="code">$else</code></dt>
+<dd><p>Commands in this branch of the <code class="code">$if</code> directive are executed if
the test fails.
</p>
</dd>
-<dt><span><code>$include</code></span></dt>
+<dt><code class="code">$include</code></dt>
<dd><p>This directive takes a single filename as an argument and reads commands
and bindings from that file.
-For example, the following directive reads from <samp>/etc/inputrc</samp>:
+For example, the following directive reads from <samp class="file">/etc/inputrc</samp>:
</p><div class="example">
-<pre class="example">$include /etc/inputrc
+<pre class="example-preformatted">$include /etc/inputrc
</pre></div>
</dd>
</dl>
<hr>
</div>
-<div class="subsection" id="Sample-Init-File">
-<div class="header">
+<div class="subsection-level-extent" id="Sample-Init-File">
+<div class="nav-panel">
<p>
Previous: <a href="#Conditional-Init-Constructs" accesskey="p" rel="prev">Conditional Init Constructs</a>, Up: <a href="#Readline-Init-File" accesskey="u" rel="up">Readline Init File</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Sample-Init-File-1"></span><h4 class="subsection">8.3.3 Sample Init File</h4>
+<h4 class="subsection" id="Sample-Init-File-1"><span>8.3.3 Sample Init File<a class="copiable-link" href="#Sample-Init-File-1"> ¶</a></span></h4>
-<p>Here is an example of an <var>inputrc</var> file. This illustrates key
+<p>Here is an example of an <var class="var">inputrc</var> file. This illustrates key
binding, variable assignment, and conditional syntax.
</p>
<div class="example">
-<pre class="example"># This file controls the behaviour of line input editing for
+<pre class="example-preformatted"># This file controls the behaviour of line input editing for
# programs that use the GNU Readline library. Existing
# programs include FTP, Bash, and GDB.
#
<hr>
</div>
</div>
-<div class="section" id="Bindable-Readline-Commands">
-<div class="header">
+<div class="section-level-extent" id="Bindable-Readline-Commands">
+<div class="nav-panel">
<p>
Next: <a href="#Readline-vi-Mode" accesskey="n" rel="next">Readline vi Mode</a>, Previous: <a href="#Readline-Init-File" accesskey="p" rel="prev">Readline Init File</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bindable-Readline-Commands-1"></span><h3 class="section">8.4 Bindable Readline Commands</h3>
+<h3 class="section" id="Bindable-Readline-Commands-1"><span>8.4 Bindable Readline Commands<a class="copiable-link" href="#Bindable-Readline-Commands-1"> ¶</a></span></h3>
<p>This section describes Readline commands that may be bound to key
sequences.
You can list your key bindings by executing
-<code>bind <span class="nolinebreak">-P</span></code><!-- /@w --> or, for a more terse format, suitable for an
-<var>inputrc</var> file, <code>bind <span class="nolinebreak">-p</span></code><!-- /@w -->. (See <a href="#Bash-Builtins">Bash Builtin Commands</a>.)
+<code class="code">bind -P</code><!-- /@w --> or, for a more terse format, suitable for an
+<var class="var">inputrc</var> file, <code class="code">bind -p</code><!-- /@w -->. (See <a class="xref" href="#Bash-Builtins">Bash Builtin Commands</a>.)
Command names without an accompanying key sequence are unbound by default.
</p>
-<p>In the following descriptions, <em>point</em> refers to the current cursor
-position, and <em>mark</em> refers to a cursor position saved by the
-<code>set-mark</code> command.
-The text between the point and mark is referred to as the <em>region</em>.
+<p>In the following descriptions, <em class="dfn">point</em> refers to the current cursor
+position, and <em class="dfn">mark</em> refers to a cursor position saved by the
+<code class="code">set-mark</code> command.
+The text between the point and mark is referred to as the <em class="dfn">region</em>.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Commands-For-Moving" accesskey="1">Commands For Moving</a></li>
<li><a href="#Commands-For-History" accesskey="2">Commands For Manipulating The History</a></li>
<li><a href="#Commands-For-Text" accesskey="3">Commands For Changing Text</a></li>
<li><a href="#Miscellaneous-Commands" accesskey="8">Some Miscellaneous Commands</a></li>
</ul>
<hr>
-<div class="subsection" id="Commands-For-Moving">
-<div class="header">
+<div class="subsection-level-extent" id="Commands-For-Moving">
+<div class="nav-panel">
<p>
Next: <a href="#Commands-For-History" accesskey="n" rel="next">Commands For Manipulating The History</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Commands-For-Moving-1"></span><h4 class="subsection">8.4.1 Commands For Moving</h4>
-<dl compact="compact">
-<dt id='index-beginning_002dof_002dline-_0028C_002da_0029'><span><code>beginning-of-line (C-a)</code><a href='#index-beginning_002dof_002dline-_0028C_002da_0029' class='copiable-anchor'> ¶</a></span></dt>
+<h4 class="subsection" id="Commands-For-Moving-1"><span>8.4.1 Commands For Moving<a class="copiable-link" href="#Commands-For-Moving-1"> ¶</a></span></h4>
+<dl class="ftable">
+<dt><a id="index-beginning_002dof_002dline-_0028C_002da_0029"></a><span><code class="code">beginning-of-line (C-a)</code><a class="copiable-link" href="#index-beginning_002dof_002dline-_0028C_002da_0029"> ¶</a></span></dt>
<dd><p>Move to the start of the current line.
</p>
</dd>
-<dt id='index-end_002dof_002dline-_0028C_002de_0029'><span><code>end-of-line (C-e)</code><a href='#index-end_002dof_002dline-_0028C_002de_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-end_002dof_002dline-_0028C_002de_0029"></a><span><code class="code">end-of-line (C-e)</code><a class="copiable-link" href="#index-end_002dof_002dline-_0028C_002de_0029"> ¶</a></span></dt>
<dd><p>Move to the end of the line.
</p>
</dd>
-<dt id='index-forward_002dchar-_0028C_002df_0029'><span><code>forward-char (C-f)</code><a href='#index-forward_002dchar-_0028C_002df_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-forward_002dchar-_0028C_002df_0029"></a><span><code class="code">forward-char (C-f)</code><a class="copiable-link" href="#index-forward_002dchar-_0028C_002df_0029"> ¶</a></span></dt>
<dd><p>Move forward a character.
</p>
</dd>
-<dt id='index-backward_002dchar-_0028C_002db_0029'><span><code>backward-char (C-b)</code><a href='#index-backward_002dchar-_0028C_002db_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-backward_002dchar-_0028C_002db_0029"></a><span><code class="code">backward-char (C-b)</code><a class="copiable-link" href="#index-backward_002dchar-_0028C_002db_0029"> ¶</a></span></dt>
<dd><p>Move back a character.
</p>
</dd>
-<dt id='index-forward_002dword-_0028M_002df_0029'><span><code>forward-word (M-f)</code><a href='#index-forward_002dword-_0028M_002df_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-forward_002dword-_0028M_002df_0029"></a><span><code class="code">forward-word (M-f)</code><a class="copiable-link" href="#index-forward_002dword-_0028M_002df_0029"> ¶</a></span></dt>
<dd><p>Move forward to the end of the next word.
Words are composed of letters and digits.
</p>
</dd>
-<dt id='index-backward_002dword-_0028M_002db_0029'><span><code>backward-word (M-b)</code><a href='#index-backward_002dword-_0028M_002db_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-backward_002dword-_0028M_002db_0029"></a><span><code class="code">backward-word (M-b)</code><a class="copiable-link" href="#index-backward_002dword-_0028M_002db_0029"> ¶</a></span></dt>
<dd><p>Move back to the start of the current or previous word.
Words are composed of letters and digits.
</p>
</dd>
-<dt id='index-shell_002dforward_002dword-_0028M_002dC_002df_0029'><span><code>shell-forward-word (M-C-f)</code><a href='#index-shell_002dforward_002dword-_0028M_002dC_002df_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shell_002dforward_002dword-_0028M_002dC_002df_0029"></a><span><code class="code">shell-forward-word (M-C-f)</code><a class="copiable-link" href="#index-shell_002dforward_002dword-_0028M_002dC_002df_0029"> ¶</a></span></dt>
<dd><p>Move forward to the end of the next word.
Words are delimited by non-quoted shell metacharacters.
</p>
</dd>
-<dt id='index-shell_002dbackward_002dword-_0028M_002dC_002db_0029'><span><code>shell-backward-word (M-C-b)</code><a href='#index-shell_002dbackward_002dword-_0028M_002dC_002db_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shell_002dbackward_002dword-_0028M_002dC_002db_0029"></a><span><code class="code">shell-backward-word (M-C-b)</code><a class="copiable-link" href="#index-shell_002dbackward_002dword-_0028M_002dC_002db_0029"> ¶</a></span></dt>
<dd><p>Move back to the start of the current or previous word.
Words are delimited by non-quoted shell metacharacters.
</p>
</dd>
-<dt id='index-previous_002dscreen_002dline-_0028_0029'><span><code>previous-screen-line ()</code><a href='#index-previous_002dscreen_002dline-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-previous_002dscreen_002dline-_0028_0029"></a><span><code class="code">previous-screen-line ()</code><a class="copiable-link" href="#index-previous_002dscreen_002dline-_0028_0029"> ¶</a></span></dt>
<dd><p>Attempt to move point to the same physical screen column on the previous
physical screen line. This will not have the desired effect if the current
Readline line does not take up more than one physical line or if point is not
greater than the length of the prompt plus the screen width.
</p>
</dd>
-<dt id='index-next_002dscreen_002dline-_0028_0029'><span><code>next-screen-line ()</code><a href='#index-next_002dscreen_002dline-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-next_002dscreen_002dline-_0028_0029"></a><span><code class="code">next-screen-line ()</code><a class="copiable-link" href="#index-next_002dscreen_002dline-_0028_0029"> ¶</a></span></dt>
<dd><p>Attempt to move point to the same physical screen column on the next
physical screen line. This will not have the desired effect if the current
Readline line does not take up more than one physical line or if the length
plus the screen width.
</p>
</dd>
-<dt id='index-clear_002ddisplay-_0028M_002dC_002dl_0029'><span><code>clear-display (M-C-l)</code><a href='#index-clear_002ddisplay-_0028M_002dC_002dl_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-clear_002ddisplay-_0028M_002dC_002dl_0029"></a><span><code class="code">clear-display (M-C-l)</code><a class="copiable-link" href="#index-clear_002ddisplay-_0028M_002dC_002dl_0029"> ¶</a></span></dt>
<dd><p>Clear the screen and, if possible, the terminal’s scrollback buffer,
then redraw the current line,
leaving the current line at the top of the screen.
</p>
</dd>
-<dt id='index-clear_002dscreen-_0028C_002dl_0029'><span><code>clear-screen (C-l)</code><a href='#index-clear_002dscreen-_0028C_002dl_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-clear_002dscreen-_0028C_002dl_0029"></a><span><code class="code">clear-screen (C-l)</code><a class="copiable-link" href="#index-clear_002dscreen-_0028C_002dl_0029"> ¶</a></span></dt>
<dd><p>Clear the screen,
then redraw the current line,
leaving the current line at the top of the screen.
</p>
</dd>
-<dt id='index-redraw_002dcurrent_002dline-_0028_0029'><span><code>redraw-current-line ()</code><a href='#index-redraw_002dcurrent_002dline-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-redraw_002dcurrent_002dline-_0028_0029"></a><span><code class="code">redraw-current-line ()</code><a class="copiable-link" href="#index-redraw_002dcurrent_002dline-_0028_0029"> ¶</a></span></dt>
<dd><p>Refresh the current line. By default, this is unbound.
</p>
</dd>
<hr>
</div>
-<div class="subsection" id="Commands-For-History">
-<div class="header">
+<div class="subsection-level-extent" id="Commands-For-History">
+<div class="nav-panel">
<p>
Next: <a href="#Commands-For-Text" accesskey="n" rel="next">Commands For Changing Text</a>, Previous: <a href="#Commands-For-Moving" accesskey="p" rel="prev">Commands For Moving</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Commands-For-Manipulating-The-History"></span><h4 class="subsection">8.4.2 Commands For Manipulating The History</h4>
+<h4 class="subsection" id="Commands-For-Manipulating-The-History"><span>8.4.2 Commands For Manipulating The History<a class="copiable-link" href="#Commands-For-Manipulating-The-History"> ¶</a></span></h4>
-<dl compact="compact">
-<dt id='index-accept_002dline-_0028Newline-or-Return_0029'><span><code>accept-line (Newline or Return)</code><a href='#index-accept_002dline-_0028Newline-or-Return_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="ftable">
+<dt><a id="index-accept_002dline-_0028Newline-or-Return_0029"></a><span><code class="code">accept-line (Newline or Return)</code><a class="copiable-link" href="#index-accept_002dline-_0028Newline-or-Return_0029"> ¶</a></span></dt>
<dd><p>Accept the line regardless of where the cursor is.
If this line is
non-empty, add it to the history list according to the setting of
-the <code>HISTCONTROL</code> and <code>HISTIGNORE</code> variables.
+the <code class="env">HISTCONTROL</code> and <code class="env">HISTIGNORE</code> variables.
If this line is a modified history line, then restore the history line
to its original state.
</p>
</dd>
-<dt id='index-previous_002dhistory-_0028C_002dp_0029'><span><code>previous-history (C-p)</code><a href='#index-previous_002dhistory-_0028C_002dp_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-previous_002dhistory-_0028C_002dp_0029"></a><span><code class="code">previous-history (C-p)</code><a class="copiable-link" href="#index-previous_002dhistory-_0028C_002dp_0029"> ¶</a></span></dt>
<dd><p>Move ‘back’ through the history list, fetching the previous command.
</p>
</dd>
-<dt id='index-next_002dhistory-_0028C_002dn_0029'><span><code>next-history (C-n)</code><a href='#index-next_002dhistory-_0028C_002dn_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-next_002dhistory-_0028C_002dn_0029"></a><span><code class="code">next-history (C-n)</code><a class="copiable-link" href="#index-next_002dhistory-_0028C_002dn_0029"> ¶</a></span></dt>
<dd><p>Move ‘forward’ through the history list, fetching the next command.
</p>
</dd>
-<dt id='index-beginning_002dof_002dhistory-_0028M_002d_003c_0029'><span><code>beginning-of-history (M-<)</code><a href='#index-beginning_002dof_002dhistory-_0028M_002d_003c_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-beginning_002dof_002dhistory-_0028M_002d_003c_0029"></a><span><code class="code">beginning-of-history (M-<)</code><a class="copiable-link" href="#index-beginning_002dof_002dhistory-_0028M_002d_003c_0029"> ¶</a></span></dt>
<dd><p>Move to the first line in the history.
</p>
</dd>
-<dt id='index-end_002dof_002dhistory-_0028M_002d_003e_0029'><span><code>end-of-history (M->)</code><a href='#index-end_002dof_002dhistory-_0028M_002d_003e_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-end_002dof_002dhistory-_0028M_002d_003e_0029"></a><span><code class="code">end-of-history (M->)</code><a class="copiable-link" href="#index-end_002dof_002dhistory-_0028M_002d_003e_0029"> ¶</a></span></dt>
<dd><p>Move to the end of the input history, i.e., the line currently
being entered.
</p>
</dd>
-<dt id='index-reverse_002dsearch_002dhistory-_0028C_002dr_0029'><span><code>reverse-search-history (C-r)</code><a href='#index-reverse_002dsearch_002dhistory-_0028C_002dr_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-reverse_002dsearch_002dhistory-_0028C_002dr_0029"></a><span><code class="code">reverse-search-history (C-r)</code><a class="copiable-link" href="#index-reverse_002dsearch_002dhistory-_0028C_002dr_0029"> ¶</a></span></dt>
<dd><p>Search backward starting at the current line and moving ‘up’ through
the history as necessary. This is an incremental search.
This command sets the region to the matched text and activates the mark.
</p>
</dd>
-<dt id='index-forward_002dsearch_002dhistory-_0028C_002ds_0029'><span><code>forward-search-history (C-s)</code><a href='#index-forward_002dsearch_002dhistory-_0028C_002ds_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-forward_002dsearch_002dhistory-_0028C_002ds_0029"></a><span><code class="code">forward-search-history (C-s)</code><a class="copiable-link" href="#index-forward_002dsearch_002dhistory-_0028C_002ds_0029"> ¶</a></span></dt>
<dd><p>Search forward starting at the current line and moving ‘down’ through
the history as necessary. This is an incremental search.
This command sets the region to the matched text and activates the mark.
</p>
</dd>
-<dt id='index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029'><span><code>non-incremental-reverse-search-history (M-p)</code><a href='#index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029"></a><span><code class="code">non-incremental-reverse-search-history (M-p)</code><a class="copiable-link" href="#index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029"> ¶</a></span></dt>
<dd><p>Search backward starting at the current line and moving ‘up’
through the history as necessary using a non-incremental search
for a string supplied by the user.
The search string may match anywhere in a history line.
</p>
</dd>
-<dt id='index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029'><span><code>non-incremental-forward-search-history (M-n)</code><a href='#index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029"></a><span><code class="code">non-incremental-forward-search-history (M-n)</code><a class="copiable-link" href="#index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029"> ¶</a></span></dt>
<dd><p>Search forward starting at the current line and moving ‘down’
through the history as necessary using a non-incremental search
for a string supplied by the user.
The search string may match anywhere in a history line.
</p>
</dd>
-<dt id='index-history_002dsearch_002dforward-_0028_0029'><span><code>history-search-forward ()</code><a href='#index-history_002dsearch_002dforward-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dsearch_002dforward-_0028_0029"></a><span><code class="code">history-search-forward ()</code><a class="copiable-link" href="#index-history_002dsearch_002dforward-_0028_0029"> ¶</a></span></dt>
<dd><p>Search forward through the history for the string of characters
between the start of the current line and the point.
The search string must match at the beginning of a history line.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-history_002dsearch_002dbackward-_0028_0029'><span><code>history-search-backward ()</code><a href='#index-history_002dsearch_002dbackward-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dsearch_002dbackward-_0028_0029"></a><span><code class="code">history-search-backward ()</code><a class="copiable-link" href="#index-history_002dsearch_002dbackward-_0028_0029"> ¶</a></span></dt>
<dd><p>Search backward through the history for the string of characters
between the start of the current line and the point.
The search string must match at the beginning of a history line.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-history_002dsubstring_002dsearch_002dforward-_0028_0029'><span><code>history-substring-search-forward ()</code><a href='#index-history_002dsubstring_002dsearch_002dforward-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dsubstring_002dsearch_002dforward-_0028_0029"></a><span><code class="code">history-substring-search-forward ()</code><a class="copiable-link" href="#index-history_002dsubstring_002dsearch_002dforward-_0028_0029"> ¶</a></span></dt>
<dd><p>Search forward through the history for the string of characters
between the start of the current line and the point.
The search string may match anywhere in a history line.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-history_002dsubstring_002dsearch_002dbackward-_0028_0029'><span><code>history-substring-search-backward ()</code><a href='#index-history_002dsubstring_002dsearch_002dbackward-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dsubstring_002dsearch_002dbackward-_0028_0029"></a><span><code class="code">history-substring-search-backward ()</code><a class="copiable-link" href="#index-history_002dsubstring_002dsearch_002dbackward-_0028_0029"> ¶</a></span></dt>
<dd><p>Search backward through the history for the string of characters
between the start of the current line and the point.
The search string may match anywhere in a history line.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-yank_002dnth_002darg-_0028M_002dC_002dy_0029'><span><code>yank-nth-arg (M-C-y)</code><a href='#index-yank_002dnth_002darg-_0028M_002dC_002dy_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-yank_002dnth_002darg-_0028M_002dC_002dy_0029"></a><span><code class="code">yank-nth-arg (M-C-y)</code><a class="copiable-link" href="#index-yank_002dnth_002darg-_0028M_002dC_002dy_0029"> ¶</a></span></dt>
<dd><p>Insert the first argument to the previous command (usually
the second word on the previous line) at point.
-With an argument <var>n</var>,
-insert the <var>n</var>th word from the previous command (the words
+With an argument <var class="var">n</var>,
+insert the <var class="var">n</var>th word from the previous command (the words
in the previous command begin with word 0). A negative argument
-inserts the <var>n</var>th word from the end of the previous command.
-Once the argument <var>n</var> is computed, the argument is extracted
-as if the ‘<samp>!<var>n</var></samp>’ history expansion had been specified.
+inserts the <var class="var">n</var>th word from the end of the previous command.
+Once the argument <var class="var">n</var> is computed, the argument is extracted
+as if the ‘<samp class="samp">!<var class="var">n</var></samp>’ history expansion had been specified.
</p>
</dd>
-<dt id='index-yank_002dlast_002darg-_0028M_002d_002e-or-M_002d_005f_0029'><span><code>yank-last-arg (M-. or M-_)</code><a href='#index-yank_002dlast_002darg-_0028M_002d_002e-or-M_002d_005f_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-yank_002dlast_002darg-_0028M_002d_002e-or-M_002d_005f_0029"></a><span><code class="code">yank-last-arg (M-. or M-_)</code><a class="copiable-link" href="#index-yank_002dlast_002darg-_0028M_002d_002e-or-M_002d_005f_0029"> ¶</a></span></dt>
<dd><p>Insert last argument to the previous command (the last word of the
previous history entry).
-With a numeric argument, behave exactly like <code>yank-nth-arg</code>.
-Successive calls to <code>yank-last-arg</code> move back through the history
+With a numeric argument, behave exactly like <code class="code">yank-nth-arg</code>.
+Successive calls to <code class="code">yank-last-arg</code> move back through the history
list, inserting the last word (or the word specified by the argument to
the first call) of each line in turn.
Any numeric argument supplied to these successive calls determines
the direction to move through the history. A negative argument switches
the direction through the history (back or forward).
The history expansion facilities are used to extract the last argument,
-as if the ‘<samp>!$</samp>’ history expansion had been specified.
+as if the ‘<samp class="samp">!$</samp>’ history expansion had been specified.
</p>
</dd>
-<dt id='index-operate_002dand_002dget_002dnext-_0028C_002do_0029'><span><code>operate-and-get-next (C-o)</code><a href='#index-operate_002dand_002dget_002dnext-_0028C_002do_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-operate_002dand_002dget_002dnext-_0028C_002do_0029"></a><span><code class="code">operate-and-get-next (C-o)</code><a class="copiable-link" href="#index-operate_002dand_002dget_002dnext-_0028C_002do_0029"> ¶</a></span></dt>
<dd><p>Accept the current line for return to the calling application as if a
newline had been entered,
and fetch the next line relative to the current line from the history
of the current line.
</p>
</dd>
-<dt id='index-fetch_002dhistory-_0028_0029'><span><code>fetch-history ()</code><a href='#index-fetch_002dhistory-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-fetch_002dhistory-_0028_0029"></a><span><code class="code">fetch-history ()</code><a class="copiable-link" href="#index-fetch_002dhistory-_0028_0029"> ¶</a></span></dt>
<dd><p>With a numeric argument, fetch that entry from the history list
and make it the current line.
Without an argument, move back to the first entry in the history list.
<hr>
</div>
-<div class="subsection" id="Commands-For-Text">
-<div class="header">
+<div class="subsection-level-extent" id="Commands-For-Text">
+<div class="nav-panel">
<p>
Next: <a href="#Commands-For-Killing" accesskey="n" rel="next">Killing And Yanking</a>, Previous: <a href="#Commands-For-History" accesskey="p" rel="prev">Commands For Manipulating The History</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Commands-For-Changing-Text"></span><h4 class="subsection">8.4.3 Commands For Changing Text</h4>
+<h4 class="subsection" id="Commands-For-Changing-Text"><span>8.4.3 Commands For Changing Text<a class="copiable-link" href="#Commands-For-Changing-Text"> ¶</a></span></h4>
-<dl compact="compact">
-<dt id='index-end_002dof_002dfile-_0028usually-C_002dd_0029'><span><code><i>end-of-file</i> (usually C-d)</code><a href='#index-end_002dof_002dfile-_0028usually-C_002dd_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="ftable">
+<dt><a id="index-end_002dof_002dfile-_0028usually-C_002dd_0029"></a><span><code class="code"><i class="i">end-of-file</i> (usually C-d)</code><a class="copiable-link" href="#index-end_002dof_002dfile-_0028usually-C_002dd_0029"> ¶</a></span></dt>
<dd><p>The character indicating end-of-file as set, for example, by
-<code>stty</code>. If this character is read when there are no characters
+<code class="code">stty</code>. If this character is read when there are no characters
on the line, and point is at the beginning of the line, Readline
-interprets it as the end of input and returns <small>EOF</small>.
+interprets it as the end of input and returns <small class="sc">EOF</small>.
</p>
</dd>
-<dt id='index-delete_002dchar-_0028C_002dd_0029'><span><code>delete-char (C-d)</code><a href='#index-delete_002dchar-_0028C_002dd_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-delete_002dchar-_0028C_002dd_0029"></a><span><code class="code">delete-char (C-d)</code><a class="copiable-link" href="#index-delete_002dchar-_0028C_002dd_0029"> ¶</a></span></dt>
<dd><p>Delete the character at point. If this function is bound to the
-same character as the tty <small>EOF</small> character, as <kbd>C-d</kbd>
+same character as the tty <small class="sc">EOF</small> character, as <kbd class="kbd">C-d</kbd>
commonly is, see above for the effects.
</p>
</dd>
-<dt id='index-backward_002ddelete_002dchar-_0028Rubout_0029'><span><code>backward-delete-char (Rubout)</code><a href='#index-backward_002ddelete_002dchar-_0028Rubout_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-backward_002ddelete_002dchar-_0028Rubout_0029"></a><span><code class="code">backward-delete-char (Rubout)</code><a class="copiable-link" href="#index-backward_002ddelete_002dchar-_0028Rubout_0029"> ¶</a></span></dt>
<dd><p>Delete the character behind the cursor. A numeric argument means
to kill the characters instead of deleting them.
</p>
</dd>
-<dt id='index-forward_002dbackward_002ddelete_002dchar-_0028_0029'><span><code>forward-backward-delete-char ()</code><a href='#index-forward_002dbackward_002ddelete_002dchar-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-forward_002dbackward_002ddelete_002dchar-_0028_0029"></a><span><code class="code">forward-backward-delete-char ()</code><a class="copiable-link" href="#index-forward_002dbackward_002ddelete_002dchar-_0028_0029"> ¶</a></span></dt>
<dd><p>Delete the character under the cursor, unless the cursor is at the
end of the line, in which case the character behind the cursor is
deleted. By default, this is not bound to a key.
</p>
</dd>
-<dt id='index-quoted_002dinsert-_0028C_002dq-or-C_002dv_0029'><span><code>quoted-insert (C-q or C-v)</code><a href='#index-quoted_002dinsert-_0028C_002dq-or-C_002dv_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-quoted_002dinsert-_0028C_002dq-or-C_002dv_0029"></a><span><code class="code">quoted-insert (C-q or C-v)</code><a class="copiable-link" href="#index-quoted_002dinsert-_0028C_002dq-or-C_002dv_0029"> ¶</a></span></dt>
<dd><p>Add the next character typed to the line verbatim. This is
-how to insert key sequences like <kbd>C-q</kbd>, for example.
+how to insert key sequences like <kbd class="kbd">C-q</kbd>, for example.
</p>
</dd>
-<dt id='index-self_002dinsert-_0028a_002c-b_002c-A_002c-1_002c-_0021_002c-_2026_0029'><span><code>self-insert (a, b, A, 1, !, …)</code><a href='#index-self_002dinsert-_0028a_002c-b_002c-A_002c-1_002c-_0021_002c-_2026_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-self_002dinsert-_0028a_002c-b_002c-A_002c-1_002c-_0021_002c-_2026_0029"></a><span><code class="code">self-insert (a, b, A, 1, !, …)</code><a class="copiable-link" href="#index-self_002dinsert-_0028a_002c-b_002c-A_002c-1_002c-_0021_002c-_2026_0029"> ¶</a></span></dt>
<dd><p>Insert yourself.
</p>
</dd>
-<dt id='index-bracketed_002dpaste_002dbegin-_0028_0029'><span><code>bracketed-paste-begin ()</code><a href='#index-bracketed_002dpaste_002dbegin-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-bracketed_002dpaste_002dbegin-_0028_0029"></a><span><code class="code">bracketed-paste-begin ()</code><a class="copiable-link" href="#index-bracketed_002dpaste_002dbegin-_0028_0029"> ¶</a></span></dt>
<dd><p>This function is intended to be bound to the "bracketed paste" escape
sequence sent by some terminals, and such a binding is assigned by default.
It allows Readline to insert the pasted text as a single unit without treating
each character as if it had been read from the keyboard. The characters
-are inserted as if each one was bound to <code>self-insert</code> instead of
+are inserted as if each one was bound to <code class="code">self-insert</code> instead of
executing any editing commands.
</p>
<p>Bracketed paste sets the region (the characters between point and the mark)
-to the inserted text. It uses the concept of an <em>active mark</em>: when the
+to the inserted text. It uses the concept of an <em class="emph">active mark</em>: when the
mark is active, Readline redisplay uses the terminal’s standout mode to
denote the region.
</p>
</dd>
-<dt id='index-transpose_002dchars-_0028C_002dt_0029'><span><code>transpose-chars (C-t)</code><a href='#index-transpose_002dchars-_0028C_002dt_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-transpose_002dchars-_0028C_002dt_0029"></a><span><code class="code">transpose-chars (C-t)</code><a class="copiable-link" href="#index-transpose_002dchars-_0028C_002dt_0029"> ¶</a></span></dt>
<dd><p>Drag the character before the cursor forward over
the character at the cursor, moving the
cursor forward as well. If the insertion point
Negative arguments have no effect.
</p>
</dd>
-<dt id='index-transpose_002dwords-_0028M_002dt_0029'><span><code>transpose-words (M-t)</code><a href='#index-transpose_002dwords-_0028M_002dt_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-transpose_002dwords-_0028M_002dt_0029"></a><span><code class="code">transpose-words (M-t)</code><a class="copiable-link" href="#index-transpose_002dwords-_0028M_002dt_0029"> ¶</a></span></dt>
<dd><p>Drag the word before point past the word after point,
moving point past that word as well.
If the insertion point is at the end of the line, this transposes
the last two words on the line.
</p>
</dd>
-<dt id='index-shell_002dtranspose_002dwords-_0028M_002dC_002dt_0029'><span><code>shell-transpose-words (M-C-t)</code><a href='#index-shell_002dtranspose_002dwords-_0028M_002dC_002dt_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shell_002dtranspose_002dwords-_0028M_002dC_002dt_0029"></a><span><code class="code">shell-transpose-words (M-C-t)</code><a class="copiable-link" href="#index-shell_002dtranspose_002dwords-_0028M_002dC_002dt_0029"> ¶</a></span></dt>
<dd><p>Drag the word before point past the word after point,
moving point past that word as well.
If the insertion point is at the end of the line, this transposes
the last two words on the line.
-Word boundaries are the same as <code>shell-forward-word</code> and
-<code>shell-backward-word</code>.
+Word boundaries are the same as <code class="code">shell-forward-word</code> and
+<code class="code">shell-backward-word</code>.
</p>
</dd>
-<dt id='index-upcase_002dword-_0028M_002du_0029'><span><code>upcase-word (M-u)</code><a href='#index-upcase_002dword-_0028M_002du_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-upcase_002dword-_0028M_002du_0029"></a><span><code class="code">upcase-word (M-u)</code><a class="copiable-link" href="#index-upcase_002dword-_0028M_002du_0029"> ¶</a></span></dt>
<dd><p>Uppercase the current (or following) word. With a negative argument,
uppercase the previous word, but do not move the cursor.
</p>
</dd>
-<dt id='index-downcase_002dword-_0028M_002dl_0029'><span><code>downcase-word (M-l)</code><a href='#index-downcase_002dword-_0028M_002dl_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-downcase_002dword-_0028M_002dl_0029"></a><span><code class="code">downcase-word (M-l)</code><a class="copiable-link" href="#index-downcase_002dword-_0028M_002dl_0029"> ¶</a></span></dt>
<dd><p>Lowercase the current (or following) word. With a negative argument,
lowercase the previous word, but do not move the cursor.
</p>
</dd>
-<dt id='index-capitalize_002dword-_0028M_002dc_0029'><span><code>capitalize-word (M-c)</code><a href='#index-capitalize_002dword-_0028M_002dc_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-capitalize_002dword-_0028M_002dc_0029"></a><span><code class="code">capitalize-word (M-c)</code><a class="copiable-link" href="#index-capitalize_002dword-_0028M_002dc_0029"> ¶</a></span></dt>
<dd><p>Capitalize the current (or following) word. With a negative argument,
capitalize the previous word, but do not move the cursor.
</p>
</dd>
-<dt id='index-overwrite_002dmode-_0028_0029'><span><code>overwrite-mode ()</code><a href='#index-overwrite_002dmode-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-overwrite_002dmode-_0028_0029"></a><span><code class="code">overwrite-mode ()</code><a class="copiable-link" href="#index-overwrite_002dmode-_0028_0029"> ¶</a></span></dt>
<dd><p>Toggle overwrite mode. With an explicit positive numeric argument,
switches to overwrite mode. With an explicit non-positive numeric
argument, switches to insert mode. This command affects only
-<code>emacs</code> mode; <code>vi</code> mode does overwrite differently.
-Each call to <code>readline()</code> starts in insert mode.
+<code class="code">emacs</code> mode; <code class="code">vi</code> mode does overwrite differently.
+Each call to <code class="code">readline()</code> starts in insert mode.
</p>
-<p>In overwrite mode, characters bound to <code>self-insert</code> replace
+<p>In overwrite mode, characters bound to <code class="code">self-insert</code> replace
the text at point rather than pushing the text to the right.
-Characters bound to <code>backward-delete-char</code> replace the character
+Characters bound to <code class="code">backward-delete-char</code> replace the character
before point with a space.
</p>
<p>By default, this command is unbound.
<hr>
</div>
-<div class="subsection" id="Commands-For-Killing">
-<div class="header">
+<div class="subsection-level-extent" id="Commands-For-Killing">
+<div class="nav-panel">
<p>
Next: <a href="#Numeric-Arguments" accesskey="n" rel="next">Specifying Numeric Arguments</a>, Previous: <a href="#Commands-For-Text" accesskey="p" rel="prev">Commands For Changing Text</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Killing-And-Yanking"></span><h4 class="subsection">8.4.4 Killing And Yanking</h4>
+<h4 class="subsection" id="Killing-And-Yanking"><span>8.4.4 Killing And Yanking<a class="copiable-link" href="#Killing-And-Yanking"> ¶</a></span></h4>
-<dl compact="compact">
-<dt id='index-kill_002dline-_0028C_002dk_0029'><span><code>kill-line (C-k)</code><a href='#index-kill_002dline-_0028C_002dk_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="ftable">
+<dt><a id="index-kill_002dline-_0028C_002dk_0029"></a><span><code class="code">kill-line (C-k)</code><a class="copiable-link" href="#index-kill_002dline-_0028C_002dk_0029"> ¶</a></span></dt>
<dd><p>Kill the text from point to the end of the line.
With a negative numeric argument, kill backward from the cursor to the
beginning of the current line.
</p>
</dd>
-<dt id='index-backward_002dkill_002dline-_0028C_002dx-Rubout_0029'><span><code>backward-kill-line (C-x Rubout)</code><a href='#index-backward_002dkill_002dline-_0028C_002dx-Rubout_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-backward_002dkill_002dline-_0028C_002dx-Rubout_0029"></a><span><code class="code">backward-kill-line (C-x Rubout)</code><a class="copiable-link" href="#index-backward_002dkill_002dline-_0028C_002dx-Rubout_0029"> ¶</a></span></dt>
<dd><p>Kill backward from the cursor to the beginning of the current line.
With a negative numeric argument, kill forward from the cursor to the
end of the current line.
</p>
</dd>
-<dt id='index-unix_002dline_002ddiscard-_0028C_002du_0029'><span><code>unix-line-discard (C-u)</code><a href='#index-unix_002dline_002ddiscard-_0028C_002du_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-unix_002dline_002ddiscard-_0028C_002du_0029"></a><span><code class="code">unix-line-discard (C-u)</code><a class="copiable-link" href="#index-unix_002dline_002ddiscard-_0028C_002du_0029"> ¶</a></span></dt>
<dd><p>Kill backward from the cursor to the beginning of the current line.
</p>
</dd>
-<dt id='index-kill_002dwhole_002dline-_0028_0029'><span><code>kill-whole-line ()</code><a href='#index-kill_002dwhole_002dline-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-kill_002dwhole_002dline-_0028_0029"></a><span><code class="code">kill-whole-line ()</code><a class="copiable-link" href="#index-kill_002dwhole_002dline-_0028_0029"> ¶</a></span></dt>
<dd><p>Kill all characters on the current line, no matter where point is.
By default, this is unbound.
</p>
</dd>
-<dt id='index-kill_002dword-_0028M_002dd_0029'><span><code>kill-word (M-d)</code><a href='#index-kill_002dword-_0028M_002dd_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-kill_002dword-_0028M_002dd_0029"></a><span><code class="code">kill-word (M-d)</code><a class="copiable-link" href="#index-kill_002dword-_0028M_002dd_0029"> ¶</a></span></dt>
<dd><p>Kill from point to the end of the current word, or if between
words, to the end of the next word.
-Word boundaries are the same as <code>forward-word</code>.
+Word boundaries are the same as <code class="code">forward-word</code>.
</p>
</dd>
-<dt id='index-backward_002dkill_002dword-_0028M_002dDEL_0029'><span><code>backward-kill-word (M-<span class="key">DEL</span>)</code><a href='#index-backward_002dkill_002dword-_0028M_002dDEL_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-backward_002dkill_002dword-_0028M_002dDEL_0029"></a><span><code class="code">backward-kill-word (M-<kbd class="key">DEL</kbd>)</code><a class="copiable-link" href="#index-backward_002dkill_002dword-_0028M_002dDEL_0029"> ¶</a></span></dt>
<dd><p>Kill the word behind point.
-Word boundaries are the same as <code>backward-word</code>.
+Word boundaries are the same as <code class="code">backward-word</code>.
</p>
</dd>
-<dt id='index-shell_002dkill_002dword-_0028M_002dC_002dd_0029'><span><code>shell-kill-word (M-C-d)</code><a href='#index-shell_002dkill_002dword-_0028M_002dC_002dd_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shell_002dkill_002dword-_0028M_002dC_002dd_0029"></a><span><code class="code">shell-kill-word (M-C-d)</code><a class="copiable-link" href="#index-shell_002dkill_002dword-_0028M_002dC_002dd_0029"> ¶</a></span></dt>
<dd><p>Kill from point to the end of the current word, or if between
words, to the end of the next word.
-Word boundaries are the same as <code>shell-forward-word</code>.
+Word boundaries are the same as <code class="code">shell-forward-word</code>.
</p>
</dd>
-<dt id='index-shell_002dbackward_002dkill_002dword-_0028_0029'><span><code>shell-backward-kill-word ()</code><a href='#index-shell_002dbackward_002dkill_002dword-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shell_002dbackward_002dkill_002dword-_0028_0029"></a><span><code class="code">shell-backward-kill-word ()</code><a class="copiable-link" href="#index-shell_002dbackward_002dkill_002dword-_0028_0029"> ¶</a></span></dt>
<dd><p>Kill the word behind point.
-Word boundaries are the same as <code>shell-backward-word</code>.
+Word boundaries are the same as <code class="code">shell-backward-word</code>.
</p>
</dd>
-<dt id='index-unix_002dword_002drubout-_0028C_002dw_0029'><span><code>unix-word-rubout (C-w)</code><a href='#index-unix_002dword_002drubout-_0028C_002dw_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-unix_002dword_002drubout-_0028C_002dw_0029"></a><span><code class="code">unix-word-rubout (C-w)</code><a class="copiable-link" href="#index-unix_002dword_002drubout-_0028C_002dw_0029"> ¶</a></span></dt>
<dd><p>Kill the word behind point, using white space as a word boundary.
The killed text is saved on the kill-ring.
</p>
</dd>
-<dt id='index-unix_002dfilename_002drubout-_0028_0029'><span><code>unix-filename-rubout ()</code><a href='#index-unix_002dfilename_002drubout-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-unix_002dfilename_002drubout-_0028_0029"></a><span><code class="code">unix-filename-rubout ()</code><a class="copiable-link" href="#index-unix_002dfilename_002drubout-_0028_0029"> ¶</a></span></dt>
<dd><p>Kill the word behind point, using white space and the slash character
as the word boundaries.
The killed text is saved on the kill-ring.
</p>
</dd>
-<dt id='index-delete_002dhorizontal_002dspace-_0028_0029'><span><code>delete-horizontal-space ()</code><a href='#index-delete_002dhorizontal_002dspace-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-delete_002dhorizontal_002dspace-_0028_0029"></a><span><code class="code">delete-horizontal-space ()</code><a class="copiable-link" href="#index-delete_002dhorizontal_002dspace-_0028_0029"> ¶</a></span></dt>
<dd><p>Delete all spaces and tabs around point. By default, this is unbound.
</p>
</dd>
-<dt id='index-kill_002dregion-_0028_0029'><span><code>kill-region ()</code><a href='#index-kill_002dregion-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-kill_002dregion-_0028_0029"></a><span><code class="code">kill-region ()</code><a class="copiable-link" href="#index-kill_002dregion-_0028_0029"> ¶</a></span></dt>
<dd><p>Kill the text in the current region.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-copy_002dregion_002das_002dkill-_0028_0029'><span><code>copy-region-as-kill ()</code><a href='#index-copy_002dregion_002das_002dkill-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-copy_002dregion_002das_002dkill-_0028_0029"></a><span><code class="code">copy-region-as-kill ()</code><a class="copiable-link" href="#index-copy_002dregion_002das_002dkill-_0028_0029"> ¶</a></span></dt>
<dd><p>Copy the text in the region to the kill buffer, so it can be yanked
right away. By default, this command is unbound.
</p>
</dd>
-<dt id='index-copy_002dbackward_002dword-_0028_0029'><span><code>copy-backward-word ()</code><a href='#index-copy_002dbackward_002dword-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-copy_002dbackward_002dword-_0028_0029"></a><span><code class="code">copy-backward-word ()</code><a class="copiable-link" href="#index-copy_002dbackward_002dword-_0028_0029"> ¶</a></span></dt>
<dd><p>Copy the word before point to the kill buffer.
-The word boundaries are the same as <code>backward-word</code>.
+The word boundaries are the same as <code class="code">backward-word</code>.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-copy_002dforward_002dword-_0028_0029'><span><code>copy-forward-word ()</code><a href='#index-copy_002dforward_002dword-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-copy_002dforward_002dword-_0028_0029"></a><span><code class="code">copy-forward-word ()</code><a class="copiable-link" href="#index-copy_002dforward_002dword-_0028_0029"> ¶</a></span></dt>
<dd><p>Copy the word following point to the kill buffer.
-The word boundaries are the same as <code>forward-word</code>.
+The word boundaries are the same as <code class="code">forward-word</code>.
By default, this command is unbound.
</p>
</dd>
-<dt id='index-yank-_0028C_002dy_0029'><span><code>yank (C-y)</code><a href='#index-yank-_0028C_002dy_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-yank-_0028C_002dy_0029"></a><span><code class="code">yank (C-y)</code><a class="copiable-link" href="#index-yank-_0028C_002dy_0029"> ¶</a></span></dt>
<dd><p>Yank the top of the kill ring into the buffer at point.
</p>
</dd>
-<dt id='index-yank_002dpop-_0028M_002dy_0029'><span><code>yank-pop (M-y)</code><a href='#index-yank_002dpop-_0028M_002dy_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-yank_002dpop-_0028M_002dy_0029"></a><span><code class="code">yank-pop (M-y)</code><a class="copiable-link" href="#index-yank_002dpop-_0028M_002dy_0029"> ¶</a></span></dt>
<dd><p>Rotate the kill-ring, and yank the new top. You can only do this if
-the prior command is <code>yank</code> or <code>yank-pop</code>.
+the prior command is <code class="code">yank</code> or <code class="code">yank-pop</code>.
</p></dd>
</dl>
<hr>
</div>
-<div class="subsection" id="Numeric-Arguments">
-<div class="header">
+<div class="subsection-level-extent" id="Numeric-Arguments">
+<div class="nav-panel">
<p>
Next: <a href="#Commands-For-Completion" accesskey="n" rel="next">Letting Readline Type For You</a>, Previous: <a href="#Commands-For-Killing" accesskey="p" rel="prev">Killing And Yanking</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Specifying-Numeric-Arguments"></span><h4 class="subsection">8.4.5 Specifying Numeric Arguments</h4>
-<dl compact="compact">
-<dt id='index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029'><span><code>digit-argument (<kbd>M-0</kbd>, <kbd>M-1</kbd>, … <kbd>M--</kbd>)</code><a href='#index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029' class='copiable-anchor'> ¶</a></span></dt>
+<h4 class="subsection" id="Specifying-Numeric-Arguments"><span>8.4.5 Specifying Numeric Arguments<a class="copiable-link" href="#Specifying-Numeric-Arguments"> ¶</a></span></h4>
+<dl class="ftable">
+<dt><a id="index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029"></a><span><code class="code">digit-argument (<kbd class="kbd">M-0</kbd>, <kbd class="kbd">M-1</kbd>, … <kbd class="kbd">M--</kbd>)</code><a class="copiable-link" href="#index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029"> ¶</a></span></dt>
<dd><p>Add this digit to the argument already accumulating, or start a new
-argument. <kbd>M--</kbd> starts a negative argument.
+argument. <kbd class="kbd">M--</kbd> starts a negative argument.
</p>
</dd>
-<dt id='index-universal_002dargument-_0028_0029'><span><code>universal-argument ()</code><a href='#index-universal_002dargument-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-universal_002dargument-_0028_0029"></a><span><code class="code">universal-argument ()</code><a class="copiable-link" href="#index-universal_002dargument-_0028_0029"> ¶</a></span></dt>
<dd><p>This is another way to specify an argument.
If this command is followed by one or more digits, optionally with a
leading minus sign, those digits define the argument.
-If the command is followed by digits, executing <code>universal-argument</code>
+If the command is followed by digits, executing <code class="code">universal-argument</code>
again ends the numeric argument, but is otherwise ignored.
As a special case, if this command is immediately followed by a
character that is neither a digit nor minus sign, the argument count
<hr>
</div>
-<div class="subsection" id="Commands-For-Completion">
-<div class="header">
+<div class="subsection-level-extent" id="Commands-For-Completion">
+<div class="nav-panel">
<p>
Next: <a href="#Keyboard-Macros" accesskey="n" rel="next">Keyboard Macros</a>, Previous: <a href="#Numeric-Arguments" accesskey="p" rel="prev">Specifying Numeric Arguments</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Letting-Readline-Type-For-You"></span><h4 class="subsection">8.4.6 Letting Readline Type For You</h4>
+<h4 class="subsection" id="Letting-Readline-Type-For-You"><span>8.4.6 Letting Readline Type For You<a class="copiable-link" href="#Letting-Readline-Type-For-You"> ¶</a></span></h4>
-<dl compact="compact">
-<dt id='index-complete-_0028TAB_0029'><span><code>complete (<span class="key">TAB</span>)</code><a href='#index-complete-_0028TAB_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="ftable">
+<dt><a id="index-complete-_0028TAB_0029"></a><span><code class="code">complete (<kbd class="key">TAB</kbd>)</code><a class="copiable-link" href="#index-complete-_0028TAB_0029"> ¶</a></span></dt>
<dd><p>Attempt to perform completion on the text before point.
The actual completion performed is application-specific.
Bash attempts completion treating the text as a variable (if the
-text begins with ‘<samp>$</samp>’), username (if the text begins with
-‘<samp>~</samp>’), hostname (if the text begins with ‘<samp>@</samp>’), or
+text begins with ‘<samp class="samp">$</samp>’), username (if the text begins with
+‘<samp class="samp">~</samp>’), hostname (if the text begins with ‘<samp class="samp">@</samp>’), or
command (including aliases and functions) in turn. If none
of these produces a match, filename completion is attempted.
</p>
</dd>
-<dt id='index-possible_002dcompletions-_0028M_002d_003f_0029'><span><code>possible-completions (M-?)</code><a href='#index-possible_002dcompletions-_0028M_002d_003f_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-possible_002dcompletions-_0028M_002d_003f_0029"></a><span><code class="code">possible-completions (M-?)</code><a class="copiable-link" href="#index-possible_002dcompletions-_0028M_002d_003f_0029"> ¶</a></span></dt>
<dd><p>List the possible completions of the text before point.
When displaying completions, Readline sets the number of columns used
-for display to the value of <code>completion-display-width</code>, the value of
-the environment variable <code>COLUMNS</code>, or the screen width, in that order.
+for display to the value of <code class="code">completion-display-width</code>, the value of
+the environment variable <code class="env">COLUMNS</code>, or the screen width, in that order.
</p>
</dd>
-<dt id='index-insert_002dcompletions-_0028M_002d_002a_0029'><span><code>insert-completions (M-*)</code><a href='#index-insert_002dcompletions-_0028M_002d_002a_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-insert_002dcompletions-_0028M_002d_002a_0029"></a><span><code class="code">insert-completions (M-*)</code><a class="copiable-link" href="#index-insert_002dcompletions-_0028M_002d_002a_0029"> ¶</a></span></dt>
<dd><p>Insert all completions of the text before point that would have
-been generated by <code>possible-completions</code>.
+been generated by <code class="code">possible-completions</code>.
</p>
</dd>
-<dt id='index-menu_002dcomplete-_0028_0029'><span><code>menu-complete ()</code><a href='#index-menu_002dcomplete-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Similar to <code>complete</code>, but replaces the word to be completed
+<dt><a id="index-menu_002dcomplete-_0028_0029"></a><span><code class="code">menu-complete ()</code><a class="copiable-link" href="#index-menu_002dcomplete-_0028_0029"> ¶</a></span></dt>
+<dd><p>Similar to <code class="code">complete</code>, but replaces the word to be completed
with a single match from the list of possible completions.
-Repeated execution of <code>menu-complete</code> steps through the list
+Repeated execution of <code class="code">menu-complete</code> steps through the list
of possible completions, inserting each match in turn.
At the end of the list of completions, the bell is rung
-(subject to the setting of <code>bell-style</code>)
+(subject to the setting of <code class="code">bell-style</code>)
and the original text is restored.
-An argument of <var>n</var> moves <var>n</var> positions forward in the list
+An argument of <var class="var">n</var> moves <var class="var">n</var> positions forward in the list
of matches; a negative argument may be used to move backward
through the list.
-This command is intended to be bound to <tt class="key">TAB</tt>, but is unbound
+This command is intended to be bound to <kbd class="key">TAB</kbd>, but is unbound
by default.
</p>
</dd>
-<dt id='index-menu_002dcomplete_002dbackward-_0028_0029'><span><code>menu-complete-backward ()</code><a href='#index-menu_002dcomplete_002dbackward-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Identical to <code>menu-complete</code>, but moves backward through the list
-of possible completions, as if <code>menu-complete</code> had been given a
+<dt><a id="index-menu_002dcomplete_002dbackward-_0028_0029"></a><span><code class="code">menu-complete-backward ()</code><a class="copiable-link" href="#index-menu_002dcomplete_002dbackward-_0028_0029"> ¶</a></span></dt>
+<dd><p>Identical to <code class="code">menu-complete</code>, but moves backward through the list
+of possible completions, as if <code class="code">menu-complete</code> had been given a
negative argument.
</p>
</dd>
-<dt id='index-delete_002dchar_002dor_002dlist-_0028_0029'><span><code>delete-char-or-list ()</code><a href='#index-delete_002dchar_002dor_002dlist-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-delete_002dchar_002dor_002dlist-_0028_0029"></a><span><code class="code">delete-char-or-list ()</code><a class="copiable-link" href="#index-delete_002dchar_002dor_002dlist-_0028_0029"> ¶</a></span></dt>
<dd><p>Deletes the character under the cursor if not at the beginning or
-end of the line (like <code>delete-char</code>).
+end of the line (like <code class="code">delete-char</code>).
If at the end of the line, behaves identically to
-<code>possible-completions</code>.
+<code class="code">possible-completions</code>.
This command is unbound by default.
</p>
</dd>
-<dt id='index-complete_002dfilename-_0028M_002d_002f_0029'><span><code>complete-filename (M-/)</code><a href='#index-complete_002dfilename-_0028M_002d_002f_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete_002dfilename-_0028M_002d_002f_0029"></a><span><code class="code">complete-filename (M-/)</code><a class="copiable-link" href="#index-complete_002dfilename-_0028M_002d_002f_0029"> ¶</a></span></dt>
<dd><p>Attempt filename completion on the text before point.
</p>
</dd>
-<dt id='index-possible_002dfilename_002dcompletions-_0028C_002dx-_002f_0029'><span><code>possible-filename-completions (C-x /)</code><a href='#index-possible_002dfilename_002dcompletions-_0028C_002dx-_002f_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-possible_002dfilename_002dcompletions-_0028C_002dx-_002f_0029"></a><span><code class="code">possible-filename-completions (C-x /)</code><a class="copiable-link" href="#index-possible_002dfilename_002dcompletions-_0028C_002dx-_002f_0029"> ¶</a></span></dt>
<dd><p>List the possible completions of the text before point,
treating it as a filename.
</p>
</dd>
-<dt id='index-complete_002dusername-_0028M_002d_007e_0029'><span><code>complete-username (M-~)</code><a href='#index-complete_002dusername-_0028M_002d_007e_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete_002dusername-_0028M_002d_007e_0029"></a><span><code class="code">complete-username (M-~)</code><a class="copiable-link" href="#index-complete_002dusername-_0028M_002d_007e_0029"> ¶</a></span></dt>
<dd><p>Attempt completion on the text before point, treating
it as a username.
</p>
</dd>
-<dt id='index-possible_002dusername_002dcompletions-_0028C_002dx-_007e_0029'><span><code>possible-username-completions (C-x ~)</code><a href='#index-possible_002dusername_002dcompletions-_0028C_002dx-_007e_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-possible_002dusername_002dcompletions-_0028C_002dx-_007e_0029"></a><span><code class="code">possible-username-completions (C-x ~)</code><a class="copiable-link" href="#index-possible_002dusername_002dcompletions-_0028C_002dx-_007e_0029"> ¶</a></span></dt>
<dd><p>List the possible completions of the text before point,
treating it as a username.
</p>
</dd>
-<dt id='index-complete_002dvariable-_0028M_002d_0024_0029'><span><code>complete-variable (M-$)</code><a href='#index-complete_002dvariable-_0028M_002d_0024_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete_002dvariable-_0028M_002d_0024_0029"></a><span><code class="code">complete-variable (M-$)</code><a class="copiable-link" href="#index-complete_002dvariable-_0028M_002d_0024_0029"> ¶</a></span></dt>
<dd><p>Attempt completion on the text before point, treating
it as a shell variable.
</p>
</dd>
-<dt id='index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029'><span><code>possible-variable-completions (C-x $)</code><a href='#index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029"></a><span><code class="code">possible-variable-completions (C-x $)</code><a class="copiable-link" href="#index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029"> ¶</a></span></dt>
<dd><p>List the possible completions of the text before point,
treating it as a shell variable.
</p>
</dd>
-<dt id='index-complete_002dhostname-_0028M_002d_0040_0029'><span><code>complete-hostname (M-@)</code><a href='#index-complete_002dhostname-_0028M_002d_0040_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete_002dhostname-_0028M_002d_0040_0029"></a><span><code class="code">complete-hostname (M-@)</code><a class="copiable-link" href="#index-complete_002dhostname-_0028M_002d_0040_0029"> ¶</a></span></dt>
<dd><p>Attempt completion on the text before point, treating
it as a hostname.
</p>
</dd>
-<dt id='index-possible_002dhostname_002dcompletions-_0028C_002dx-_0040_0029'><span><code>possible-hostname-completions (C-x @)</code><a href='#index-possible_002dhostname_002dcompletions-_0028C_002dx-_0040_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-possible_002dhostname_002dcompletions-_0028C_002dx-_0040_0029"></a><span><code class="code">possible-hostname-completions (C-x @)</code><a class="copiable-link" href="#index-possible_002dhostname_002dcompletions-_0028C_002dx-_0040_0029"> ¶</a></span></dt>
<dd><p>List the possible completions of the text before point,
treating it as a hostname.
</p>
</dd>
-<dt id='index-complete_002dcommand-_0028M_002d_0021_0029'><span><code>complete-command (M-!)</code><a href='#index-complete_002dcommand-_0028M_002d_0021_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete_002dcommand-_0028M_002d_0021_0029"></a><span><code class="code">complete-command (M-!)</code><a class="copiable-link" href="#index-complete_002dcommand-_0028M_002d_0021_0029"> ¶</a></span></dt>
<dd><p>Attempt completion on the text before point, treating
it as a command name. Command completion attempts to
match the text against aliases, reserved words, shell
in that order.
</p>
</dd>
-<dt id='index-possible_002dcommand_002dcompletions-_0028C_002dx-_0021_0029'><span><code>possible-command-completions (C-x !)</code><a href='#index-possible_002dcommand_002dcompletions-_0028C_002dx-_0021_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-possible_002dcommand_002dcompletions-_0028C_002dx-_0021_0029"></a><span><code class="code">possible-command-completions (C-x !)</code><a class="copiable-link" href="#index-possible_002dcommand_002dcompletions-_0028C_002dx-_0021_0029"> ¶</a></span></dt>
<dd><p>List the possible completions of the text before point,
treating it as a command name.
</p>
</dd>
-<dt id='index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029'><span><code>dynamic-complete-history (M-<span class="key">TAB</span>)</code><a href='#index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029"></a><span><code class="code">dynamic-complete-history (M-<kbd class="key">TAB</kbd>)</code><a class="copiable-link" href="#index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029"> ¶</a></span></dt>
<dd><p>Attempt completion on the text before point, comparing
the text against lines from the history list for possible
completion matches.
</p>
</dd>
-<dt id='index-dabbrev_002dexpand-_0028_0029'><span><code>dabbrev-expand ()</code><a href='#index-dabbrev_002dexpand-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-dabbrev_002dexpand-_0028_0029"></a><span><code class="code">dabbrev-expand ()</code><a class="copiable-link" href="#index-dabbrev_002dexpand-_0028_0029"> ¶</a></span></dt>
<dd><p>Attempt menu completion on the text before point, comparing
the text against lines from the history list for possible
completion matches.
</p>
</dd>
-<dt id='index-complete_002dinto_002dbraces-_0028M_002d_007b_0029'><span><code>complete-into-braces (M-{)</code><a href='#index-complete_002dinto_002dbraces-_0028M_002d_007b_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete_002dinto_002dbraces-_0028M_002d_007b_0029"></a><span><code class="code">complete-into-braces (M-{)</code><a class="copiable-link" href="#index-complete_002dinto_002dbraces-_0028M_002d_007b_0029"> ¶</a></span></dt>
<dd><p>Perform filename completion and insert the list of possible completions
enclosed within braces so the list is available to the shell
-(see <a href="#Brace-Expansion">Brace Expansion</a>).
+(see <a class="pxref" href="#Brace-Expansion">Brace Expansion</a>).
</p>
</dd>
</dl>
<hr>
</div>
-<div class="subsection" id="Keyboard-Macros">
-<div class="header">
+<div class="subsection-level-extent" id="Keyboard-Macros">
+<div class="nav-panel">
<p>
Next: <a href="#Miscellaneous-Commands" accesskey="n" rel="next">Some Miscellaneous Commands</a>, Previous: <a href="#Commands-For-Completion" accesskey="p" rel="prev">Letting Readline Type For You</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Keyboard-Macros-1"></span><h4 class="subsection">8.4.7 Keyboard Macros</h4>
-<dl compact="compact">
-<dt id='index-start_002dkbd_002dmacro-_0028C_002dx-_0028_0029'><span><code>start-kbd-macro (C-x ()</code><a href='#index-start_002dkbd_002dmacro-_0028C_002dx-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<h4 class="subsection" id="Keyboard-Macros-1"><span>8.4.7 Keyboard Macros<a class="copiable-link" href="#Keyboard-Macros-1"> ¶</a></span></h4>
+<dl class="ftable">
+<dt><a id="index-start_002dkbd_002dmacro-_0028C_002dx-_0028_0029"></a><span><code class="code">start-kbd-macro (C-x ()</code><a class="copiable-link" href="#index-start_002dkbd_002dmacro-_0028C_002dx-_0028_0029"> ¶</a></span></dt>
<dd><p>Begin saving the characters typed into the current keyboard macro.
</p>
</dd>
-<dt id='index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029'><span><code>end-kbd-macro (C-x ))</code><a href='#index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029"></a><span><code class="code">end-kbd-macro (C-x ))</code><a class="copiable-link" href="#index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029"> ¶</a></span></dt>
<dd><p>Stop saving the characters typed into the current keyboard macro
and save the definition.
</p>
</dd>
-<dt id='index-call_002dlast_002dkbd_002dmacro-_0028C_002dx-e_0029'><span><code>call-last-kbd-macro (C-x e)</code><a href='#index-call_002dlast_002dkbd_002dmacro-_0028C_002dx-e_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-call_002dlast_002dkbd_002dmacro-_0028C_002dx-e_0029"></a><span><code class="code">call-last-kbd-macro (C-x e)</code><a class="copiable-link" href="#index-call_002dlast_002dkbd_002dmacro-_0028C_002dx-e_0029"> ¶</a></span></dt>
<dd><p>Re-execute the last keyboard macro defined, by making the characters
in the macro appear as if typed at the keyboard.
</p>
</dd>
-<dt id='index-print_002dlast_002dkbd_002dmacro-_0028_0029'><span><code>print-last-kbd-macro ()</code><a href='#index-print_002dlast_002dkbd_002dmacro-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-print_002dlast_002dkbd_002dmacro-_0028_0029"></a><span><code class="code">print-last-kbd-macro ()</code><a class="copiable-link" href="#index-print_002dlast_002dkbd_002dmacro-_0028_0029"> ¶</a></span></dt>
<dd><p>Print the last keyboard macro defined in a format suitable for the
-<var>inputrc</var> file.
+<var class="var">inputrc</var> file.
</p>
</dd>
</dl>
<hr>
</div>
-<div class="subsection" id="Miscellaneous-Commands">
-<div class="header">
+<div class="subsection-level-extent" id="Miscellaneous-Commands">
+<div class="nav-panel">
<p>
Previous: <a href="#Keyboard-Macros" accesskey="p" rel="prev">Keyboard Macros</a>, Up: <a href="#Bindable-Readline-Commands" accesskey="u" rel="up">Bindable Readline Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Some-Miscellaneous-Commands"></span><h4 class="subsection">8.4.8 Some Miscellaneous Commands</h4>
-<dl compact="compact">
-<dt id='index-re_002dread_002dinit_002dfile-_0028C_002dx-C_002dr_0029'><span><code>re-read-init-file (C-x C-r)</code><a href='#index-re_002dread_002dinit_002dfile-_0028C_002dx-C_002dr_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Read in the contents of the <var>inputrc</var> file, and incorporate
+<h4 class="subsection" id="Some-Miscellaneous-Commands"><span>8.4.8 Some Miscellaneous Commands<a class="copiable-link" href="#Some-Miscellaneous-Commands"> ¶</a></span></h4>
+<dl class="ftable">
+<dt><a id="index-re_002dread_002dinit_002dfile-_0028C_002dx-C_002dr_0029"></a><span><code class="code">re-read-init-file (C-x C-r)</code><a class="copiable-link" href="#index-re_002dread_002dinit_002dfile-_0028C_002dx-C_002dr_0029"> ¶</a></span></dt>
+<dd><p>Read in the contents of the <var class="var">inputrc</var> file, and incorporate
any bindings or variable assignments found there.
</p>
</dd>
-<dt id='index-abort-_0028C_002dg_0029'><span><code>abort (C-g)</code><a href='#index-abort-_0028C_002dg_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-abort-_0028C_002dg_0029"></a><span><code class="code">abort (C-g)</code><a class="copiable-link" href="#index-abort-_0028C_002dg_0029"> ¶</a></span></dt>
<dd><p>Abort the current editing command and
ring the terminal’s bell (subject to the setting of
-<code>bell-style</code>).
+<code class="code">bell-style</code>).
</p>
</dd>
-<dt id='index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029'><span><code>do-lowercase-version (M-A, M-B, M-<var>x</var>, …)</code><a href='#index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>If the metafied character <var>x</var> is upper case, run the command
+<dt><a id="index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029"></a><span><code class="code">do-lowercase-version (M-A, M-B, M-<var class="var">x</var>, …)</code><a class="copiable-link" href="#index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029"> ¶</a></span></dt>
+<dd><p>If the metafied character <var class="var">x</var> is upper case, run the command
that is bound to the corresponding metafied lower case character.
-The behavior is undefined if <var>x</var> is already lower case.
+The behavior is undefined if <var class="var">x</var> is already lower case.
</p>
</dd>
-<dt id='index-prefix_002dmeta-_0028ESC_0029'><span><code>prefix-meta (<span class="key">ESC</span>)</code><a href='#index-prefix_002dmeta-_0028ESC_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-prefix_002dmeta-_0028ESC_0029"></a><span><code class="code">prefix-meta (<kbd class="key">ESC</kbd>)</code><a class="copiable-link" href="#index-prefix_002dmeta-_0028ESC_0029"> ¶</a></span></dt>
<dd><p>Metafy the next character typed. This is for keyboards
-without a meta key. Typing ‘<samp><span class="key">ESC</span> f</samp>’ is equivalent to typing
-<kbd>M-f</kbd>.
+without a meta key. Typing ‘<samp class="samp"><kbd class="key">ESC</kbd> f</samp>’ is equivalent to typing
+<kbd class="kbd">M-f</kbd>.
</p>
</dd>
-<dt id='index-undo-_0028C_002d_005f-or-C_002dx-C_002du_0029'><span><code>undo (C-_ or C-x C-u)</code><a href='#index-undo-_0028C_002d_005f-or-C_002dx-C_002du_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-undo-_0028C_002d_005f-or-C_002dx-C_002du_0029"></a><span><code class="code">undo (C-_ or C-x C-u)</code><a class="copiable-link" href="#index-undo-_0028C_002d_005f-or-C_002dx-C_002du_0029"> ¶</a></span></dt>
<dd><p>Incremental undo, separately remembered for each line.
</p>
</dd>
-<dt id='index-revert_002dline-_0028M_002dr_0029'><span><code>revert-line (M-r)</code><a href='#index-revert_002dline-_0028M_002dr_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Undo all changes made to this line. This is like executing the <code>undo</code>
+<dt><a id="index-revert_002dline-_0028M_002dr_0029"></a><span><code class="code">revert-line (M-r)</code><a class="copiable-link" href="#index-revert_002dline-_0028M_002dr_0029"> ¶</a></span></dt>
+<dd><p>Undo all changes made to this line. This is like executing the <code class="code">undo</code>
command enough times to get back to the beginning.
</p>
</dd>
-<dt id='index-tilde_002dexpand-_0028M_002d_0026_0029'><span><code>tilde-expand (M-&)</code><a href='#index-tilde_002dexpand-_0028M_002d_0026_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-tilde_002dexpand-_0028M_002d_0026_0029"></a><span><code class="code">tilde-expand (M-&)</code><a class="copiable-link" href="#index-tilde_002dexpand-_0028M_002d_0026_0029"> ¶</a></span></dt>
<dd><p>Perform tilde expansion on the current word.
</p>
</dd>
-<dt id='index-set_002dmark-_0028C_002d_0040_0029'><span><code>set-mark (C-@)</code><a href='#index-set_002dmark-_0028C_002d_0040_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-set_002dmark-_0028C_002d_0040_0029"></a><span><code class="code">set-mark (C-@)</code><a class="copiable-link" href="#index-set_002dmark-_0028C_002d_0040_0029"> ¶</a></span></dt>
<dd><p>Set the mark to the point. If a
numeric argument is supplied, the mark is set to that position.
</p>
</dd>
-<dt id='index-exchange_002dpoint_002dand_002dmark-_0028C_002dx-C_002dx_0029'><span><code>exchange-point-and-mark (C-x C-x)</code><a href='#index-exchange_002dpoint_002dand_002dmark-_0028C_002dx-C_002dx_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-exchange_002dpoint_002dand_002dmark-_0028C_002dx-C_002dx_0029"></a><span><code class="code">exchange-point-and-mark (C-x C-x)</code><a class="copiable-link" href="#index-exchange_002dpoint_002dand_002dmark-_0028C_002dx-C_002dx_0029"> ¶</a></span></dt>
<dd><p>Swap the point with the mark. The current cursor position is set to
the saved position, and the old cursor position is saved as the mark.
</p>
</dd>
-<dt id='index-character_002dsearch-_0028C_002d_005d_0029'><span><code>character-search (C-])</code><a href='#index-character_002dsearch-_0028C_002d_005d_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-character_002dsearch-_0028C_002d_005d_0029"></a><span><code class="code">character-search (C-])</code><a class="copiable-link" href="#index-character_002dsearch-_0028C_002d_005d_0029"> ¶</a></span></dt>
<dd><p>A character is read and point is moved to the next occurrence of that
character. A negative argument searches for previous occurrences.
</p>
</dd>
-<dt id='index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029'><span><code>character-search-backward (M-C-])</code><a href='#index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029"></a><span><code class="code">character-search-backward (M-C-])</code><a class="copiable-link" href="#index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029"> ¶</a></span></dt>
<dd><p>A character is read and point is moved to the previous occurrence
of that character. A negative argument searches for subsequent
occurrences.
</p>
</dd>
-<dt id='index-skip_002dcsi_002dsequence-_0028_0029'><span><code>skip-csi-sequence ()</code><a href='#index-skip_002dcsi_002dsequence-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-skip_002dcsi_002dsequence-_0028_0029"></a><span><code class="code">skip-csi-sequence ()</code><a class="copiable-link" href="#index-skip_002dcsi_002dsequence-_0028_0029"> ¶</a></span></dt>
<dd><p>Read enough characters to consume a multi-key sequence such as those
defined for keys like Home and End. Such sequences begin with a
Control Sequence Indicator (CSI), usually ESC-[. If this sequence is
but usually bound to ESC-[.
</p>
</dd>
-<dt id='index-insert_002dcomment-_0028M_002d_0023_0029'><span><code>insert-comment (M-#)</code><a href='#index-insert_002dcomment-_0028M_002d_0023_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Without a numeric argument, the value of the <code>comment-begin</code>
+<dt><a id="index-insert_002dcomment-_0028M_002d_0023_0029"></a><span><code class="code">insert-comment (M-#)</code><a class="copiable-link" href="#index-insert_002dcomment-_0028M_002d_0023_0029"> ¶</a></span></dt>
+<dd><p>Without a numeric argument, the value of the <code class="code">comment-begin</code>
variable is inserted at the beginning of the current line.
If a numeric argument is supplied, this command acts as a toggle: if
the characters at the beginning of the line do not match the value
-of <code>comment-begin</code>, the value is inserted, otherwise
-the characters in <code>comment-begin</code> are deleted from the beginning of
+of <code class="code">comment-begin</code>, the value is inserted, otherwise
+the characters in <code class="code">comment-begin</code> are deleted from the beginning of
the line.
In either case, the line is accepted as if a newline had been typed.
-The default value of <code>comment-begin</code> causes this command
+The default value of <code class="code">comment-begin</code> causes this command
to make the current line a shell comment.
If a numeric argument causes the comment character to be removed, the line
will be executed by the shell.
</p>
</dd>
-<dt id='index-dump_002dfunctions-_0028_0029'><span><code>dump-functions ()</code><a href='#index-dump_002dfunctions-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-dump_002dfunctions-_0028_0029"></a><span><code class="code">dump-functions ()</code><a class="copiable-link" href="#index-dump_002dfunctions-_0028_0029"> ¶</a></span></dt>
<dd><p>Print all of the functions and their key bindings to the
Readline output stream. If a numeric argument is supplied,
the output is formatted in such a way that it can be made part
-of an <var>inputrc</var> file. This command is unbound by default.
+of an <var class="var">inputrc</var> file. This command is unbound by default.
</p>
</dd>
-<dt id='index-dump_002dvariables-_0028_0029'><span><code>dump-variables ()</code><a href='#index-dump_002dvariables-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-dump_002dvariables-_0028_0029"></a><span><code class="code">dump-variables ()</code><a class="copiable-link" href="#index-dump_002dvariables-_0028_0029"> ¶</a></span></dt>
<dd><p>Print all of the settable variables and their values to the
Readline output stream. If a numeric argument is supplied,
the output is formatted in such a way that it can be made part
-of an <var>inputrc</var> file. This command is unbound by default.
+of an <var class="var">inputrc</var> file. This command is unbound by default.
</p>
</dd>
-<dt id='index-dump_002dmacros-_0028_0029'><span><code>dump-macros ()</code><a href='#index-dump_002dmacros-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-dump_002dmacros-_0028_0029"></a><span><code class="code">dump-macros ()</code><a class="copiable-link" href="#index-dump_002dmacros-_0028_0029"> ¶</a></span></dt>
<dd><p>Print all of the Readline key sequences bound to macros and the
strings they output. If a numeric argument is supplied,
the output is formatted in such a way that it can be made part
-of an <var>inputrc</var> file. This command is unbound by default.
+of an <var class="var">inputrc</var> file. This command is unbound by default.
</p>
</dd>
-<dt id='index-spell_002dcorrect_002dword-_0028C_002dx-s_0029'><span><code>spell-correct-word (C-x s)</code><a href='#index-spell_002dcorrect_002dword-_0028C_002dx-s_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-spell_002dcorrect_002dword-_0028C_002dx-s_0029"></a><span><code class="code">spell-correct-word (C-x s)</code><a class="copiable-link" href="#index-spell_002dcorrect_002dword-_0028C_002dx-s_0029"> ¶</a></span></dt>
<dd><p>Perform spelling correction on the current word, treating it as a directory
-or filename, in the same way as the <code>cdspell</code> shell option.
-Word boundaries are the same as those used by <code>shell-forward-word</code>.
+or filename, in the same way as the <code class="code">cdspell</code> shell option.
+Word boundaries are the same as those used by <code class="code">shell-forward-word</code>.
</p>
</dd>
-<dt id='index-glob_002dcomplete_002dword-_0028M_002dg_0029'><span><code>glob-complete-word (M-g)</code><a href='#index-glob_002dcomplete_002dword-_0028M_002dg_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-glob_002dcomplete_002dword-_0028M_002dg_0029"></a><span><code class="code">glob-complete-word (M-g)</code><a class="copiable-link" href="#index-glob_002dcomplete_002dword-_0028M_002dg_0029"> ¶</a></span></dt>
<dd><p>The word before point is treated as a pattern for pathname expansion,
with an asterisk implicitly appended. This pattern is used to
generate a list of matching file names for possible completions.
</p>
</dd>
-<dt id='index-glob_002dexpand_002dword-_0028C_002dx-_002a_0029'><span><code>glob-expand-word (C-x *)</code><a href='#index-glob_002dexpand_002dword-_0028C_002dx-_002a_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-glob_002dexpand_002dword-_0028C_002dx-_002a_0029"></a><span><code class="code">glob-expand-word (C-x *)</code><a class="copiable-link" href="#index-glob_002dexpand_002dword-_0028C_002dx-_002a_0029"> ¶</a></span></dt>
<dd><p>The word before point is treated as a pattern for pathname expansion,
and the list of matching file names is inserted, replacing the word.
-If a numeric argument is supplied, a ‘<samp>*</samp>’ is appended before
+If a numeric argument is supplied, a ‘<samp class="samp">*</samp>’ is appended before
pathname expansion.
</p>
</dd>
-<dt id='index-glob_002dlist_002dexpansions-_0028C_002dx-g_0029'><span><code>glob-list-expansions (C-x g)</code><a href='#index-glob_002dlist_002dexpansions-_0028C_002dx-g_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-glob_002dlist_002dexpansions-_0028C_002dx-g_0029"></a><span><code class="code">glob-list-expansions (C-x g)</code><a class="copiable-link" href="#index-glob_002dlist_002dexpansions-_0028C_002dx-g_0029"> ¶</a></span></dt>
<dd><p>The list of expansions that would have been generated by
-<code>glob-expand-word</code> is displayed, and the line is redrawn.
-If a numeric argument is supplied, a ‘<samp>*</samp>’ is appended before
+<code class="code">glob-expand-word</code> is displayed, and the line is redrawn.
+If a numeric argument is supplied, a ‘<samp class="samp">*</samp>’ is appended before
pathname expansion.
</p>
</dd>
-<dt id='index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029'><span><code>display-shell-version (C-x C-v)</code><a href='#index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029"></a><span><code class="code">display-shell-version (C-x C-v)</code><a class="copiable-link" href="#index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029"> ¶</a></span></dt>
<dd><p>Display version information about the current instance of Bash.
</p>
</dd>
-<dt id='index-shell_002dexpand_002dline-_0028M_002dC_002de_0029'><span><code>shell-expand-line (M-C-e)</code><a href='#index-shell_002dexpand_002dline-_0028M_002dC_002de_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-shell_002dexpand_002dline-_0028M_002dC_002de_0029"></a><span><code class="code">shell-expand-line (M-C-e)</code><a class="copiable-link" href="#index-shell_002dexpand_002dline-_0028M_002dC_002de_0029"> ¶</a></span></dt>
<dd><p>Expand the line by performing shell word expansions.
This performs alias and history expansion,
-$’<var>string</var>’ and $"<var>string</var>" quoting,
-tilde expansion, parameter and variable expansion, arithmetic expansion,
+$’<var class="var">string</var>’ and $"<var class="var">string</var>" quoting,
+tilde expansion, parameter and variable expansion, arithmetic expansion,
+command and proces substitution,
word splitting, and quote removal.
+An explicit argument suppresses command and process substitution.
</p>
</dd>
-<dt id='index-history_002dexpand_002dline-_0028M_002d_005e_0029'><span><code>history-expand-line (M-^)</code><a href='#index-history_002dexpand_002dline-_0028M_002d_005e_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dexpand_002dline-_0028M_002d_005e_0029"></a><span><code class="code">history-expand-line (M-^)</code><a class="copiable-link" href="#index-history_002dexpand_002dline-_0028M_002d_005e_0029"> ¶</a></span></dt>
<dd><p>Perform history expansion on the current line.
</p>
</dd>
-<dt id='index-magic_002dspace-_0028_0029'><span><code>magic-space ()</code><a href='#index-magic_002dspace-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-magic_002dspace-_0028_0029"></a><span><code class="code">magic-space ()</code><a class="copiable-link" href="#index-magic_002dspace-_0028_0029"> ¶</a></span></dt>
<dd><p>Perform history expansion on the current line and insert a space
-(see <a href="#History-Interaction">History Expansion</a>).
+(see <a class="pxref" href="#History-Interaction">History Expansion</a>).
</p>
</dd>
-<dt id='index-alias_002dexpand_002dline-_0028_0029'><span><code>alias-expand-line ()</code><a href='#index-alias_002dexpand_002dline-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>Perform alias expansion on the current line (see <a href="#Aliases">Aliases</a>).
+<dt><a id="index-alias_002dexpand_002dline-_0028_0029"></a><span><code class="code">alias-expand-line ()</code><a class="copiable-link" href="#index-alias_002dexpand_002dline-_0028_0029"> ¶</a></span></dt>
+<dd><p>Perform alias expansion on the current line (see <a class="pxref" href="#Aliases">Aliases</a>).
</p>
</dd>
-<dt id='index-history_002dand_002dalias_002dexpand_002dline-_0028_0029'><span><code>history-and-alias-expand-line ()</code><a href='#index-history_002dand_002dalias_002dexpand_002dline-_0028_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history_002dand_002dalias_002dexpand_002dline-_0028_0029"></a><span><code class="code">history-and-alias-expand-line ()</code><a class="copiable-link" href="#index-history_002dand_002dalias_002dexpand_002dline-_0028_0029"> ¶</a></span></dt>
<dd><p>Perform history and alias expansion on the current line.
</p>
</dd>
-<dt id='index-insert_002dlast_002dargument-_0028M_002d_002e-or-M_002d_005f_0029'><span><code>insert-last-argument (M-. or M-_)</code><a href='#index-insert_002dlast_002dargument-_0028M_002d_002e-or-M_002d_005f_0029' class='copiable-anchor'> ¶</a></span></dt>
-<dd><p>A synonym for <code>yank-last-arg</code>.
+<dt><a id="index-insert_002dlast_002dargument-_0028M_002d_002e-or-M_002d_005f_0029"></a><span><code class="code">insert-last-argument (M-. or M-_)</code><a class="copiable-link" href="#index-insert_002dlast_002dargument-_0028M_002d_002e-or-M_002d_005f_0029"> ¶</a></span></dt>
+<dd><p>A synonym for <code class="code">yank-last-arg</code>.
</p>
</dd>
-<dt id='index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029'><span><code>edit-and-execute-command (C-x C-e)</code><a href='#index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"></a><span><code class="code">edit-and-execute-command (C-x C-e)</code><a class="copiable-link" href="#index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"> ¶</a></span></dt>
<dd><p>Invoke an editor on the current command line, and execute the result as shell
commands.
Bash attempts to invoke
-<code>$VISUAL</code>, <code>$EDITOR</code>, and <code>emacs</code>
+<code class="code">$VISUAL</code>, <code class="code">$EDITOR</code>, and <code class="code">emacs</code>
as the editor, in that order.
</p>
</dd>
-<dt id='index-execute_002dnamed_002dcommand-_0028M_002dx_0029'><span><code>execute-named-command (M-x)</code><a href='#index-execute_002dnamed_002dcommand-_0028M_002dx_0029' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-execute_002dnamed_002dcommand-_0028M_002dx_0029"></a><span><code class="code">execute-named-command (M-x)</code><a class="copiable-link" href="#index-execute_002dnamed_002dcommand-_0028M_002dx_0029"> ¶</a></span></dt>
<dd><p>Read a bindable readline command name from the input and execute the
function to which it’s bound, as if the key sequence to which it was
bound appeared in the input.
<hr>
</div>
</div>
-<div class="section" id="Readline-vi-Mode">
-<div class="header">
+<div class="section-level-extent" id="Readline-vi-Mode">
+<div class="nav-panel">
<p>
Next: <a href="#Programmable-Completion" accesskey="n" rel="next">Programmable Completion</a>, Previous: <a href="#Bindable-Readline-Commands" accesskey="p" rel="prev">Bindable Readline Commands</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Readline-vi-Mode-1"></span><h3 class="section">8.5 Readline vi Mode</h3>
+<h3 class="section" id="Readline-vi-Mode-1"><span>8.5 Readline vi Mode<a class="copiable-link" href="#Readline-vi-Mode-1"> ¶</a></span></h3>
-<p>While the Readline library does not have a full set of <code>vi</code>
+<p>While the Readline library does not have a full set of <code class="code">vi</code>
editing functions, it does contain enough to allow simple editing
-of the line. The Readline <code>vi</code> mode behaves as specified in
-the <small>POSIX</small> standard.
+of the line. The Readline <code class="code">vi</code> mode behaves as specified in
+the <small class="sc">POSIX</small> standard.
</p>
-<p>In order to switch interactively between <code>emacs</code> and <code>vi</code>
-editing modes, use the ‘<samp>set -o emacs</samp>’ and ‘<samp>set -o vi</samp>’
-commands (see <a href="#The-Set-Builtin">The Set Builtin</a>).
-The Readline default is <code>emacs</code> mode.
+<p>In order to switch interactively between <code class="code">emacs</code> and <code class="code">vi</code>
+editing modes, use the ‘<samp class="samp">set -o emacs</samp>’ and ‘<samp class="samp">set -o vi</samp>’
+commands (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
+The Readline default is <code class="code">emacs</code> mode.
</p>
-<p>When you enter a line in <code>vi</code> mode, you are already placed in
-‘insertion’ mode, as if you had typed an ‘<samp>i</samp>’. Pressing <tt class="key">ESC</tt>
+<p>When you enter a line in <code class="code">vi</code> mode, you are already placed in
+‘insertion’ mode, as if you had typed an ‘<samp class="samp">i</samp>’. Pressing <kbd class="key">ESC</kbd>
switches you into ‘command’ mode, where you can edit the text of the
-line with the standard <code>vi</code> movement keys, move to previous
-history lines with ‘<samp>k</samp>’ and subsequent lines with ‘<samp>j</samp>’, and
+line with the standard <code class="code">vi</code> movement keys, move to previous
+history lines with ‘<samp class="samp">k</samp>’ and subsequent lines with ‘<samp class="samp">j</samp>’, and
so forth.
</p>
<hr>
</div>
-<div class="section" id="Programmable-Completion">
-<div class="header">
+<div class="section-level-extent" id="Programmable-Completion">
+<div class="nav-panel">
<p>
Next: <a href="#Programmable-Completion-Builtins" accesskey="n" rel="next">Programmable Completion Builtins</a>, Previous: <a href="#Readline-vi-Mode" accesskey="p" rel="prev">Readline vi Mode</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Programmable-Completion-1"></span><h3 class="section">8.6 Programmable Completion</h3>
-<span id="index-programmable-completion"></span>
+<h3 class="section" id="Programmable-Completion-1"><span>8.6 Programmable Completion<a class="copiable-link" href="#Programmable-Completion-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-programmable-completion"></a>
<p>When word completion is attempted for an argument to a command for
-which a completion specification (a <var>compspec</var>) has been defined
-using the <code>complete</code> builtin (see <a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a>),
+which a completion specification (a <var class="var">compspec</var>) has been defined
+using the <code class="code">complete</code> builtin (see <a class="pxref" href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a>),
the programmable completion facilities are invoked.
</p>
<p>First, the command name is identified.
compspec is used to generate the list of possible completions for the word.
If the command word is the empty string (completion attempted at the
beginning of an empty line), any compspec defined with
-the <samp>-E</samp> option to <code>complete</code> is used.
+the <samp class="option">-E</samp> option to <code class="code">complete</code> is used.
If the command word is a full pathname, a compspec for the full
pathname is searched for first.
If no compspec is found for the full pathname, an attempt is made to
find a compspec for the portion following the final slash.
If those searches do not result in a compspec, any compspec defined with
-the <samp>-D</samp> option to <code>complete</code> is used as the default.
+the <samp class="option">-D</samp> option to <code class="code">complete</code> is used as the default.
If there is no default compspec, Bash attempts alias expansion
on the command word as a final resort, and attempts to find a compspec
for the command word from any successful expansion
<p>Once a compspec has been found, it is used to generate the list of
matching words.
If a compspec is not found, the default Bash completion
-described above (see <a href="#Commands-For-Completion">Letting Readline Type For You</a>) is performed.
+described above (see <a class="pxref" href="#Commands-For-Completion">Letting Readline Type For You</a>) is performed.
</p>
<p>First, the actions specified by the compspec are used.
Only matches which are prefixed by the word being completed are
returned.
-When the <samp>-f</samp> or <samp>-d</samp> option is used for filename or
-directory name completion, the shell variable <code>FIGNORE</code> is
+When the <samp class="option">-f</samp> or <samp class="option">-d</samp> option is used for filename or
+directory name completion, the shell variable <code class="env">FIGNORE</code> is
used to filter the matches.
-See <a href="#Bash-Variables">Bash Variables</a>, for a description of <code>FIGNORE</code>.
+See <a class="xref" href="#Bash-Variables">Bash Variables</a>, for a description of <code class="env">FIGNORE</code>.
</p>
<p>Any completions specified by a filename expansion pattern to the
-<samp>-G</samp> option are generated next.
+<samp class="option">-G</samp> option are generated next.
The words generated by the pattern need not match the word being completed.
-The <code>GLOBIGNORE</code> shell variable is not used to filter the matches,
-but the <code>FIGNORE</code> shell variable is used.
+The <code class="env">GLOBIGNORE</code> shell variable is not used to filter the matches,
+but the <code class="env">FIGNORE</code> shell variable is used.
</p>
-<p>Next, the string specified as the argument to the <samp>-W</samp> option
+<p>Next, the string specified as the argument to the <samp class="option">-W</samp> option
is considered.
-The string is first split using the characters in the <code>IFS</code>
+The string is first split using the characters in the <code class="env">IFS</code>
special variable as delimiters.
Shell quoting is honored within the string, in order to provide a
mechanism for the words to contain shell metacharacters or characters
-in the value of <code>IFS</code>.
+in the value of <code class="env">IFS</code>.
Each word is then expanded using
brace expansion, tilde expansion, parameter and variable expansion,
command substitution, and arithmetic expansion,
-as described above (see <a href="#Shell-Expansions">Shell Expansions</a>).
+as described above (see <a class="pxref" href="#Shell-Expansions">Shell Expansions</a>).
The results are split using the rules described above
-(see <a href="#Word-Splitting">Word Splitting</a>).
+(see <a class="pxref" href="#Word-Splitting">Word Splitting</a>).
The results of the expansion are prefix-matched against the word being
completed, and the matching words become the possible completions.
</p>
<p>After these matches have been generated, any shell function or command
-specified with the <samp>-F</samp> and <samp>-C</samp> options is invoked.
-When the command or function is invoked, the <code>COMP_LINE</code>,
-<code>COMP_POINT</code>, <code>COMP_KEY</code>, and <code>COMP_TYPE</code> variables are
-assigned values as described above (see <a href="#Bash-Variables">Bash Variables</a>).
-If a shell function is being invoked, the <code>COMP_WORDS</code> and
-<code>COMP_CWORD</code> variables are also set.
+specified with the <samp class="option">-F</samp> and <samp class="option">-C</samp> options is invoked.
+When the command or function is invoked, the <code class="env">COMP_LINE</code>,
+<code class="env">COMP_POINT</code>, <code class="env">COMP_KEY</code>, and <code class="env">COMP_TYPE</code> variables are
+assigned values as described above (see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
+If a shell function is being invoked, the <code class="env">COMP_WORDS</code> and
+<code class="env">COMP_CWORD</code> variables are also set.
When the function or command is invoked, the first argument ($1) is the
name of the command whose arguments are being completed, the
second argument ($2) is the word being completed, and the third argument
is performed; the function or command has complete freedom in generating
the matches.
</p>
-<p>Any function specified with <samp>-F</samp> is invoked first.
+<p>Any function specified with <samp class="option">-F</samp> is invoked first.
The function may use any of the shell facilities, including the
-<code>compgen</code> and <code>compopt</code> builtins described below
-(see <a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a>), to generate the matches.
-It must put the possible completions in the <code>COMPREPLY</code> array
+<code class="code">compgen</code> and <code class="code">compopt</code> builtins described below
+(see <a class="pxref" href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a>), to generate the matches.
+It must put the possible completions in the <code class="env">COMPREPLY</code> array
variable, one per array element.
</p>
-<p>Next, any command specified with the <samp>-C</samp> option is invoked
+<p>Next, any command specified with the <samp class="option">-C</samp> option is invoked
in an environment equivalent to command substitution.
It should print a list of completions, one per line, to
the standard output.
Backslash may be used to escape a newline, if necessary.
</p>
<p>After all of the possible completions are generated, any filter
-specified with the <samp>-X</samp> option is applied to the list.
-The filter is a pattern as used for pathname expansion; a ‘<samp>&</samp>’
+specified with the <samp class="option">-X</samp> option is applied to the list.
+The filter is a pattern as used for pathname expansion; a ‘<samp class="samp">&</samp>’
in the pattern is replaced with the text of the word being completed.
-A literal ‘<samp>&</samp>’ may be escaped with a backslash; the backslash
+A literal ‘<samp class="samp">&</samp>’ may be escaped with a backslash; the backslash
is removed before attempting a match.
Any completion that matches the pattern will be removed from the list.
-A leading ‘<samp>!</samp>’ negates the pattern; in this case any completion
+A leading ‘<samp class="samp">!</samp>’ negates the pattern; in this case any completion
not matching the pattern will be removed.
-If the <code>nocasematch</code> shell option
-(see the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+If the <code class="code">nocasematch</code> shell option
+(see the description of <code class="code">shopt</code> in <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
is enabled, the match is performed without regard to the case
of alphabetic characters.
</p>
-<p>Finally, any prefix and suffix specified with the <samp>-P</samp> and <samp>-S</samp>
+<p>Finally, any prefix and suffix specified with the <samp class="option">-P</samp> and <samp class="option">-S</samp>
options are added to each member of the completion list, and the result is
returned to the Readline completion code as the list of possible
completions.
</p>
<p>If the previously-applied actions do not generate any matches, and the
-<samp>-o dirnames</samp> option was supplied to <code>complete</code> when the
+<samp class="option">-o dirnames</samp> option was supplied to <code class="code">complete</code> when the
compspec was defined, directory name completion is attempted.
</p>
-<p>If the <samp>-o plusdirs</samp> option was supplied to <code>complete</code> when
+<p>If the <samp class="option">-o plusdirs</samp> option was supplied to <code class="code">complete</code> when
the compspec was defined, directory name completion is attempted and any
matches are added to the results of the other actions.
</p>
the completion code as the full set of possible completions.
The default Bash completions are not attempted, and the Readline default
of filename completion is disabled.
-If the <samp>-o bashdefault</samp> option was supplied to <code>complete</code> when
+If the <samp class="option">-o bashdefault</samp> option was supplied to <code class="code">complete</code> when
the compspec was defined, the default Bash completions are attempted
if the compspec generates no matches.
-If the <samp>-o default</samp> option was supplied to <code>complete</code> when the
+If the <samp class="option">-o default</samp> option was supplied to <code class="code">complete</code> when the
compspec was defined, Readline’s default completion will be performed
if the compspec (and, if attempted, the default Bash completions)
generate no matches.
<p>When a compspec indicates that directory name completion is desired,
the programmable completion functions force Readline to append a slash
to completed names which are symbolic links to directories, subject to
-the value of the <var>mark-directories</var> Readline variable, regardless
-of the setting of the <var>mark-symlinked-directories</var> Readline variable.
+the value of the <var class="var">mark-directories</var> Readline variable, regardless
+of the setting of the <var class="var">mark-symlinked-directories</var> Readline variable.
</p>
<p>There is some support for dynamically modifying completions. This is
most useful when used in combination with a default completion specified
-with <samp>-D</samp>. It’s possible for shell functions executed as completion
+with <samp class="option">-D</samp>. It’s possible for shell functions executed as completion
handlers to indicate that completion should be retried by returning an
exit status of 124. If a shell function returns 124, and changes
the compspec associated with the command on which completion is being
completion function would load completions dynamically:
</p>
<div class="example">
-<pre class="example">_completion_loader()
+<pre class="example-preformatted">_completion_loader()
{
. "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124
}
<hr>
</div>
-<div class="section" id="Programmable-Completion-Builtins">
-<div class="header">
+<div class="section-level-extent" id="Programmable-Completion-Builtins">
+<div class="nav-panel">
<p>
Next: <a href="#A-Programmable-Completion-Example" accesskey="n" rel="next">A Programmable Completion Example</a>, Previous: <a href="#Programmable-Completion" accesskey="p" rel="prev">Programmable Completion</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Programmable-Completion-Builtins-1"></span><h3 class="section">8.7 Programmable Completion Builtins</h3>
-<span id="index-completion-builtins"></span>
+<h3 class="section" id="Programmable-Completion-Builtins-1"><span>8.7 Programmable Completion Builtins<a class="copiable-link" href="#Programmable-Completion-Builtins-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-completion-builtins"></a>
<p>Three builtin commands are available to manipulate the programmable completion
facilities: one to specify how the arguments to a particular command are to
be completed, and two to modify the completion as it is happening.
</p>
-<dl compact="compact">
-<dt id='index-compgen'><span><code>compgen</code><a href='#index-compgen' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-compgen"></a><span><code class="code">compgen</code><a class="copiable-link" href="#index-compgen"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example"><code>compgen [-V <var>varname</var>] [<var>option</var>] [<var>word</var>]</code>
+<pre class="example-preformatted"><code class="code">compgen [-V <var class="var">varname</var>] [<var class="var">option</var>] [<var class="var">word</var>]</code>
</pre></div>
-<p>Generate possible completion matches for <var>word</var> according to
-the <var>option</var>s, which may be any option accepted by the
-<code>complete</code>
+<p>Generate possible completion matches for <var class="var">word</var> according to
+the <var class="var">option</var>s, which may be any option accepted by the
+<code class="code">complete</code>
builtin with the exceptions of
-<samp>-p</samp>,
-<samp>-r</samp>,
-<samp>-D</samp>,
-<samp>-E</samp>,
+<samp class="option">-p</samp>,
+<samp class="option">-r</samp>,
+<samp class="option">-D</samp>,
+<samp class="option">-E</samp>,
and
-<samp>-I</samp>,
+<samp class="option">-I</samp>,
and write the matches to the standard output.
</p>
-<p>If the <samp>-V</samp> option is supplied, <code>compgen</code> stores the generated
-completions into the indexed array variable <var>varname</var> instead of writing
+<p>If the <samp class="option">-V</samp> option is supplied, <code class="code">compgen</code> stores the generated
+completions into the indexed array variable <var class="var">varname</var> instead of writing
them to the standard output.
</p>
-<p>When using the <samp>-F</samp> or <samp>-C</samp> options, the various shell variables
+<p>When using the <samp class="option">-F</samp> or <samp class="option">-C</samp> options, the various shell variables
set by the programmable completion facilities, while available, will not
have useful values.
</p>
<p>The matches will be generated in the same way as if the programmable
completion code had generated them directly from a completion specification
with the same flags.
-If <var>word</var> is specified, only those completions matching <var>word</var>
+If <var class="var">word</var> is specified, only those completions matching <var class="var">word</var>
will be displayed.
</p>
<p>The return value is true unless an invalid option is supplied, or no
matches were generated.
</p>
</dd>
-<dt id='index-complete'><span><code>complete</code><a href='#index-complete' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-complete"></a><span><code class="code">complete</code><a class="copiable-link" href="#index-complete"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example"><code>complete [-abcdefgjksuv] [-o <var>comp-option</var>] [-DEI] [-A <var>action</var>]
-[-G <var>globpat</var>] [-W <var>wordlist</var>] [-F <var>function</var>] [-C <var>command</var>]
-[-X <var>filterpat</var>] [-P <var>prefix</var>] [-S <var>suffix</var>] <var>name</var> [<var>name</var> …]</code>
-<code>complete -pr [-DEI] [<var>name</var> …]</code>
+<pre class="example-preformatted"><code class="code">complete [-abcdefgjksuv] [-o <var class="var">comp-option</var>] [-DEI] [-A <var class="var">action</var>]
+[-G <var class="var">globpat</var>] [-W <var class="var">wordlist</var>] [-F <var class="var">function</var>] [-C <var class="var">command</var>]
+[-X <var class="var">filterpat</var>] [-P <var class="var">prefix</var>] [-S <var class="var">suffix</var>] <var class="var">name</var> [<var class="var">name</var> ...]</code>
+<code class="code">complete -pr [-DEI] [<var class="var">name</var> ...]</code>
</pre></div>
-<p>Specify how arguments to each <var>name</var> should be completed.
-If the <samp>-p</samp> option is supplied, or if no options are supplied, existing
+<p>Specify how arguments to each <var class="var">name</var> should be completed.
+If the <samp class="option">-p</samp> option is supplied, or if no options or <var class="var">name</var>s
+are supplied, existing
completion specifications are printed in a way that allows them to be
reused as input.
-The <samp>-r</samp> option removes a completion specification for
-each <var>name</var>, or, if no <var>name</var>s are supplied, all
+The <samp class="option">-r</samp> option removes a completion specification for
+each <var class="var">name</var>, or, if no <var class="var">name</var>s are supplied, all
completion specifications.
-The <samp>-D</samp> option indicates that other supplied options and actions should
+The <samp class="option">-D</samp> option indicates that other supplied options and actions should
apply to the “default” command completion; that is, completion attempted
on a command for which no completion has previously been defined.
-The <samp>-E</samp> option indicates that other supplied options and actions should
+The <samp class="option">-E</samp> option indicates that other supplied options and actions should
apply to “empty” command completion; that is, completion attempted on a
blank line.
-The <samp>-I</samp> option indicates that other supplied options and actions should
+The <samp class="option">-I</samp> option indicates that other supplied options and actions should
apply to completion on the initial non-assignment word on the line, or after a
-command delimiter such as ‘<samp>;</samp>’ or ‘<samp>|</samp>’, which is usually command
+command delimiter such as ‘<samp class="samp">;</samp>’ or ‘<samp class="samp">|</samp>’, which is usually command
name completion.
-If multiple options are supplied, the <samp>-D</samp> option takes precedence
-over <samp>-E</samp>, and both take precedence over <samp>-I</samp>.
-If any of <samp>-D</samp>, <samp>-E</samp>, or <samp>-I</samp> are supplied, any other
-<var>name</var> arguments are ignored; these completions only apply to the case
+If multiple options are supplied, the <samp class="option">-D</samp> option takes precedence
+over <samp class="option">-E</samp>, and both take precedence over <samp class="option">-I</samp>.
+If any of <samp class="option">-D</samp>, <samp class="option">-E</samp>, or <samp class="option">-I</samp> are supplied, any other
+<var class="var">name</var> arguments are ignored; these completions only apply to the case
specified by the option.
</p>
<p>The process of applying these completion specifications when word completion
-is attempted is described above (see <a href="#Programmable-Completion">Programmable Completion</a>).
+is attempted is described above (see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
</p>
<p>Other options, if specified, have the following meanings.
-The arguments to the <samp>-G</samp>, <samp>-W</samp>, and <samp>-X</samp> options
-(and, if necessary, the <samp>-P</samp> and <samp>-S</samp> options)
+The arguments to the <samp class="option">-G</samp>, <samp class="option">-W</samp>, and <samp class="option">-X</samp> options
+(and, if necessary, the <samp class="option">-P</samp> and <samp class="option">-S</samp> options)
should be quoted to protect them from expansion before the
-<code>complete</code> builtin is invoked.
+<code class="code">complete</code> builtin is invoked.
</p>
-<dl compact="compact">
-<dt><span><code>-o <var>comp-option</var></code></span></dt>
-<dd><p>The <var>comp-option</var> controls several aspects of the compspec’s behavior
+<dl class="table">
+<dt><code class="code">-o <var class="var">comp-option</var></code></dt>
+<dd><p>The <var class="var">comp-option</var> controls several aspects of the compspec’s behavior
beyond the simple generation of completions.
-<var>comp-option</var> may be one of:
+<var class="var">comp-option</var> may be one of:
</p>
-<dl compact="compact">
-<dt><span><code>bashdefault</code></span></dt>
+<dl class="table">
+<dt><code class="code">bashdefault</code></dt>
<dd><p>Perform the rest of the default Bash completions if the compspec
generates no matches.
</p>
</dd>
-<dt><span><code>default</code></span></dt>
+<dt><code class="code">default</code></dt>
<dd><p>Use Readline’s default filename completion if the compspec generates
no matches.
</p>
</dd>
-<dt><span><code>dirnames</code></span></dt>
+<dt><code class="code">dirnames</code></dt>
<dd><p>Perform directory name completion if the compspec generates no matches.
</p>
</dd>
-<dt><span><code>filenames</code></span></dt>
+<dt><code class="code">filenames</code></dt>
<dd><p>Tell Readline that the compspec generates filenames, so it can perform any
filename-specific processing (like adding a slash to directory names,
quoting special characters, or suppressing trailing spaces).
This option is intended to be used with shell functions specified
-with <samp>-F</samp>.
+with <samp class="option">-F</samp>.
</p>
</dd>
-<dt><span><code>fullquote</code></span></dt>
+<dt><code class="code">fullquote</code></dt>
<dd><p>Tell Readline to quote all the completed words even if they are not
filenames.
</p>
</dd>
-<dt><span><code>noquote</code></span></dt>
+<dt><code class="code">noquote</code></dt>
<dd><p>Tell Readline not to quote the completed words if they are filenames
(quoting filenames is the default).
</p>
</dd>
-<dt><span><code>nosort</code></span></dt>
+<dt><code class="code">nosort</code></dt>
<dd><p>Tell Readline not to sort the list of possible completions alphabetically.
</p>
</dd>
-<dt><span><code>nospace</code></span></dt>
+<dt><code class="code">nospace</code></dt>
<dd><p>Tell Readline not to append a space (the default) to words completed at
the end of the line.
</p>
</dd>
-<dt><span><code>plusdirs</code></span></dt>
+<dt><code class="code">plusdirs</code></dt>
<dd><p>After any matches defined by the compspec are generated,
directory name completion is attempted and any
matches are added to the results of the other actions.
</dl>
</dd>
-<dt><span><code>-A <var>action</var></code></span></dt>
-<dd><p>The <var>action</var> may be one of the following to generate a list of possible
+<dt><code class="code">-A <var class="var">action</var></code></dt>
+<dd><p>The <var class="var">action</var> may be one of the following to generate a list of possible
completions:
</p>
-<dl compact="compact">
-<dt><span><code>alias</code></span></dt>
-<dd><p>Alias names. May also be specified as <samp>-a</samp>.
+<dl class="table">
+<dt><code class="code">alias</code></dt>
+<dd><p>Alias names. May also be specified as <samp class="option">-a</samp>.
</p>
</dd>
-<dt><span><code>arrayvar</code></span></dt>
+<dt><code class="code">arrayvar</code></dt>
<dd><p>Array variable names.
</p>
</dd>
-<dt><span><code>binding</code></span></dt>
-<dd><p>Readline key binding names (see <a href="#Bindable-Readline-Commands">Bindable Readline Commands</a>).
+<dt><code class="code">binding</code></dt>
+<dd><p>Readline key binding names (see <a class="pxref" href="#Bindable-Readline-Commands">Bindable Readline Commands</a>).
</p>
</dd>
-<dt><span><code>builtin</code></span></dt>
-<dd><p>Names of shell builtin commands. May also be specified as <samp>-b</samp>.
+<dt><code class="code">builtin</code></dt>
+<dd><p>Names of shell builtin commands. May also be specified as <samp class="option">-b</samp>.
</p>
</dd>
-<dt><span><code>command</code></span></dt>
-<dd><p>Command names. May also be specified as <samp>-c</samp>.
+<dt><code class="code">command</code></dt>
+<dd><p>Command names. May also be specified as <samp class="option">-c</samp>.
</p>
</dd>
-<dt><span><code>directory</code></span></dt>
-<dd><p>Directory names. May also be specified as <samp>-d</samp>.
+<dt><code class="code">directory</code></dt>
+<dd><p>Directory names. May also be specified as <samp class="option">-d</samp>.
</p>
</dd>
-<dt><span><code>disabled</code></span></dt>
+<dt><code class="code">disabled</code></dt>
<dd><p>Names of disabled shell builtins.
</p>
</dd>
-<dt><span><code>enabled</code></span></dt>
+<dt><code class="code">enabled</code></dt>
<dd><p>Names of enabled shell builtins.
</p>
</dd>
-<dt><span><code>export</code></span></dt>
-<dd><p>Names of exported shell variables. May also be specified as <samp>-e</samp>.
+<dt><code class="code">export</code></dt>
+<dd><p>Names of exported shell variables. May also be specified as <samp class="option">-e</samp>.
</p>
</dd>
-<dt><span><code>file</code></span></dt>
-<dd><p>File names. May also be specified as <samp>-f</samp>.
+<dt><code class="code">file</code></dt>
+<dd><p>File names. May also be specified as <samp class="option">-f</samp>.
</p>
</dd>
-<dt><span><code>function</code></span></dt>
+<dt><code class="code">function</code></dt>
<dd><p>Names of shell functions.
</p>
</dd>
-<dt><span><code>group</code></span></dt>
-<dd><p>Group names. May also be specified as <samp>-g</samp>.
+<dt><code class="code">group</code></dt>
+<dd><p>Group names. May also be specified as <samp class="option">-g</samp>.
</p>
</dd>
-<dt><span><code>helptopic</code></span></dt>
-<dd><p>Help topics as accepted by the <code>help</code> builtin (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+<dt><code class="code">helptopic</code></dt>
+<dd><p>Help topics as accepted by the <code class="code">help</code> builtin (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p>
</dd>
-<dt><span><code>hostname</code></span></dt>
+<dt><code class="code">hostname</code></dt>
<dd><p>Hostnames, as taken from the file specified by the
-<code>HOSTFILE</code> shell variable (see <a href="#Bash-Variables">Bash Variables</a>).
+<code class="env">HOSTFILE</code> shell variable (see <a class="pxref" href="#Bash-Variables">Bash Variables</a>).
</p>
</dd>
-<dt><span><code>job</code></span></dt>
-<dd><p>Job names, if job control is active. May also be specified as <samp>-j</samp>.
+<dt><code class="code">job</code></dt>
+<dd><p>Job names, if job control is active. May also be specified as <samp class="option">-j</samp>.
</p>
</dd>
-<dt><span><code>keyword</code></span></dt>
-<dd><p>Shell reserved words. May also be specified as <samp>-k</samp>.
+<dt><code class="code">keyword</code></dt>
+<dd><p>Shell reserved words. May also be specified as <samp class="option">-k</samp>.
</p>
</dd>
-<dt><span><code>running</code></span></dt>
+<dt><code class="code">running</code></dt>
<dd><p>Names of running jobs, if job control is active.
</p>
</dd>
-<dt><span><code>service</code></span></dt>
-<dd><p>Service names. May also be specified as <samp>-s</samp>.
+<dt><code class="code">service</code></dt>
+<dd><p>Service names. May also be specified as <samp class="option">-s</samp>.
</p>
</dd>
-<dt><span><code>setopt</code></span></dt>
-<dd><p>Valid arguments for the <samp>-o</samp> option to the <code>set</code> builtin
-(see <a href="#The-Set-Builtin">The Set Builtin</a>).
+<dt><code class="code">setopt</code></dt>
+<dd><p>Valid arguments for the <samp class="option">-o</samp> option to the <code class="code">set</code> builtin
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
</p>
</dd>
-<dt><span><code>shopt</code></span></dt>
-<dd><p>Shell option names as accepted by the <code>shopt</code> builtin
-(see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+<dt><code class="code">shopt</code></dt>
+<dd><p>Shell option names as accepted by the <code class="code">shopt</code> builtin
+(see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p>
</dd>
-<dt><span><code>signal</code></span></dt>
+<dt><code class="code">signal</code></dt>
<dd><p>Signal names.
</p>
</dd>
-<dt><span><code>stopped</code></span></dt>
+<dt><code class="code">stopped</code></dt>
<dd><p>Names of stopped jobs, if job control is active.
</p>
</dd>
-<dt><span><code>user</code></span></dt>
-<dd><p>User names. May also be specified as <samp>-u</samp>.
+<dt><code class="code">user</code></dt>
+<dd><p>User names. May also be specified as <samp class="option">-u</samp>.
</p>
</dd>
-<dt><span><code>variable</code></span></dt>
-<dd><p>Names of all shell variables. May also be specified as <samp>-v</samp>.
+<dt><code class="code">variable</code></dt>
+<dd><p>Names of all shell variables. May also be specified as <samp class="option">-v</samp>.
</p></dd>
</dl>
</dd>
-<dt><span><code>-C <var>command</var></code></span></dt>
-<dd><p><var>command</var> is executed in a subshell environment, and its output is
+<dt><code class="code">-C <var class="var">command</var></code></dt>
+<dd><p><var class="var">command</var> is executed in a subshell environment, and its output is
used as the possible completions.
-Arguments are passed as with the <samp>-F</samp> option.
+Arguments are passed as with the <samp class="option">-F</samp> option.
</p>
</dd>
-<dt><span><code>-F <var>function</var></code></span></dt>
-<dd><p>The shell function <var>function</var> is executed in the current shell
+<dt><code class="code">-F <var class="var">function</var></code></dt>
+<dd><p>The shell function <var class="var">function</var> is executed in the current shell
environment.
When it is executed, $1 is the name of the command whose arguments are
being completed, $2 is the word being completed, and $3 is the word
preceding the word being completed, as described above
-(see <a href="#Programmable-Completion">Programmable Completion</a>).
+(see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
When it finishes, the possible completions are retrieved from the value
-of the <code>COMPREPLY</code> array variable.
+of the <code class="env">COMPREPLY</code> array variable.
</p>
</dd>
-<dt><span><code>-G <var>globpat</var></code></span></dt>
-<dd><p>The filename expansion pattern <var>globpat</var> is expanded to generate
+<dt><code class="code">-G <var class="var">globpat</var></code></dt>
+<dd><p>The filename expansion pattern <var class="var">globpat</var> is expanded to generate
the possible completions.
</p>
</dd>
-<dt><span><code>-P <var>prefix</var></code></span></dt>
-<dd><p><var>prefix</var> is added at the beginning of each possible completion
+<dt><code class="code">-P <var class="var">prefix</var></code></dt>
+<dd><p><var class="var">prefix</var> is added at the beginning of each possible completion
after all other options have been applied.
</p>
</dd>
-<dt><span><code>-S <var>suffix</var></code></span></dt>
-<dd><p><var>suffix</var> is appended to each possible completion
+<dt><code class="code">-S <var class="var">suffix</var></code></dt>
+<dd><p><var class="var">suffix</var> is appended to each possible completion
after all other options have been applied.
</p>
</dd>
-<dt><span><code>-W <var>wordlist</var></code></span></dt>
-<dd><p>The <var>wordlist</var> is split using the characters in the
-<code>IFS</code> special variable as delimiters, and each resultant word
+<dt><code class="code">-W <var class="var">wordlist</var></code></dt>
+<dd><p>The <var class="var">wordlist</var> is split using the characters in the
+<code class="env">IFS</code> special variable as delimiters, and each resultant word
is expanded.
The possible completions are the members of the resultant list which
match the word being completed.
</p>
</dd>
-<dt><span><code>-X <var>filterpat</var></code></span></dt>
-<dd><p><var>filterpat</var> is a pattern as used for filename expansion.
+<dt><code class="code">-X <var class="var">filterpat</var></code></dt>
+<dd><p><var class="var">filterpat</var> is a pattern as used for filename expansion.
It is applied to the list of possible completions generated by the
preceding options and arguments, and each completion matching
-<var>filterpat</var> is removed from the list.
-A leading ‘<samp>!</samp>’ in <var>filterpat</var> negates the pattern; in this
-case, any completion not matching <var>filterpat</var> is removed.
+<var class="var">filterpat</var> is removed from the list.
+A leading ‘<samp class="samp">!</samp>’ in <var class="var">filterpat</var> negates the pattern; in this
+case, any completion not matching <var class="var">filterpat</var> is removed.
</p></dd>
</dl>
<p>The return value is true unless an invalid option is supplied, an option
other than
-<samp>-p</samp>,
-<samp>-r</samp>,
-<samp>-D</samp>,
-<samp>-E</samp>,
+<samp class="option">-p</samp>,
+<samp class="option">-r</samp>,
+<samp class="option">-D</samp>,
+<samp class="option">-E</samp>,
or
-<samp>-I</samp>
-is supplied without a <var>name</var>
+<samp class="option">-I</samp>
+is supplied without a <var class="var">name</var>
argument, an attempt is made to remove a completion specification for
-a <var>name</var> for which no specification exists, or
+a <var class="var">name</var> for which no specification exists, or
an error occurs adding a completion specification.
</p>
</dd>
-<dt id='index-compopt'><span><code>compopt</code><a href='#index-compopt' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-compopt"></a><span><code class="code">compopt</code><a class="copiable-link" href="#index-compopt"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example"><code>compopt</code> [-o <var>option</var>] [-DEI] [+o <var>option</var>] [<var>name</var>]
+<pre class="example-preformatted"><code class="code">compopt</code> [-o <var class="var">option</var>] [-DEI] [+o <var class="var">option</var>] [<var class="var">name</var>]
</pre></div>
-<p>Modify completion options for each <var>name</var> according to the
-<var>option</var>s, or for the currently-executing completion if no <var>name</var>s
+<p>Modify completion options for each <var class="var">name</var> according to the
+<var class="var">option</var>s, or for the currently-executing completion if no <var class="var">name</var>s
are supplied.
-If no <var>option</var>s are given, display the completion options for each
-<var>name</var> or the current completion.
-The possible values of <var>option</var> are those valid for the <code>complete</code>
+If no <var class="var">option</var>s are given, display the completion options for each
+<var class="var">name</var> or the current completion.
+The possible values of <var class="var">option</var> are those valid for the <code class="code">complete</code>
builtin described above.
-The <samp>-D</samp> option indicates that other supplied options should
+The <samp class="option">-D</samp> option indicates that other supplied options should
apply to the “default” command completion; that is, completion attempted
on a command for which no completion has previously been defined.
-The <samp>-E</samp> option indicates that other supplied options should
+The <samp class="option">-E</samp> option indicates that other supplied options should
apply to “empty” command completion; that is, completion attempted on a
blank line.
-The <samp>-I</samp> option indicates that other supplied options should
+The <samp class="option">-I</samp> option indicates that other supplied options should
apply to completion on the initial non-assignment word on the line, or after a
-command delimiter such as ‘<samp>;</samp>’ or ‘<samp>|</samp>’, which is usually command
+command delimiter such as ‘<samp class="samp">;</samp>’ or ‘<samp class="samp">|</samp>’, which is usually command
name completion.
</p>
-<p>If multiple options are supplied, the <samp>-D</samp> option takes precedence
-over <samp>-E</samp>, and both take precedence over <samp>-I</samp>
+<p>If multiple options are supplied, the <samp class="option">-D</samp> option takes precedence
+over <samp class="option">-E</samp>, and both take precedence over <samp class="option">-I</samp>
</p>
<p>The return value is true unless an invalid option is supplied, an attempt
-is made to modify the options for a <var>name</var> for which no completion
+is made to modify the options for a <var class="var">name</var> for which no completion
specification exists, or an output error occurs.
</p>
</dd>
<hr>
</div>
-<div class="section" id="A-Programmable-Completion-Example">
-<div class="header">
+<div class="section-level-extent" id="A-Programmable-Completion-Example">
+<div class="nav-panel">
<p>
Previous: <a href="#Programmable-Completion-Builtins" accesskey="p" rel="prev">Programmable Completion Builtins</a>, Up: <a href="#Command-Line-Editing" accesskey="u" rel="up">Command Line Editing</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="A-Programmable-Completion-Example-1"></span><h3 class="section">8.8 A Programmable Completion Example</h3>
+<h3 class="section" id="A-Programmable-Completion-Example-1"><span>8.8 A Programmable Completion Example<a class="copiable-link" href="#A-Programmable-Completion-Example-1"> ¶</a></span></h3>
<p>The most common way to obtain additional completion functionality beyond
-the default actions <code>complete</code> and <code>compgen</code> provide is to use
-a shell function and bind it to a particular command using <code>complete -F</code>.
+the default actions <code class="code">complete</code> and <code class="code">compgen</code> provide is to use
+a shell function and bind it to a particular command using <code class="code">complete -F</code>.
</p>
-<p>The following function provides completions for the <code>cd</code> builtin.
+<p>The following function provides completions for the <code class="code">cd</code> builtin.
It is a reasonably good example of what shell functions must do when
-used for completion. This function uses the word passed as <code>$2</code>
+used for completion. This function uses the word passed as <code class="code">$2</code>
to determine the directory name to complete. You can also use the
-<code>COMP_WORDS</code> array variable; the current word is indexed by the
-<code>COMP_CWORD</code> variable.
+<code class="code">COMP_WORDS</code> array variable; the current word is indexed by the
+<code class="code">COMP_CWORD</code> variable.
</p>
-<p>The function relies on the <code>complete</code> and <code>compgen</code> builtins
-to do much of the work, adding only the things that the Bash <code>cd</code>
+<p>The function relies on the <code class="code">complete</code> and <code class="code">compgen</code> builtins
+to do much of the work, adding only the things that the Bash <code class="code">cd</code>
does beyond accepting basic directory names:
-tilde expansion (see <a href="#Tilde-Expansion">Tilde Expansion</a>),
-searching directories in <var>$CDPATH</var>, which is described above
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>),
-and basic support for the <code>cdable_vars</code> shell option
-(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>).
-<code>_comp_cd</code> modifies the value of <var>IFS</var> so that it contains only
+tilde expansion (see <a class="pxref" href="#Tilde-Expansion">Tilde Expansion</a>),
+searching directories in <var class="var">$CDPATH</var>, which is described above
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>),
+and basic support for the <code class="code">cdable_vars</code> shell option
+(see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>).
+<code class="code">_comp_cd</code> modifies the value of <var class="var">IFS</var> so that it contains only
a newline to accommodate file names containing spaces and tabs –
-<code>compgen</code> prints the possible completions it generates one per line.
+<code class="code">compgen</code> prints the possible completions it generates one per line.
</p>
-<p>Possible completions go into the <var>COMPREPLY</var> array variable, one
+<p>Possible completions go into the <var class="var">COMPREPLY</var> array variable, one
completion per array element. The programmable completion system retrieves
the completions from there when the function returns.
</p>
<div class="example">
-<pre class="example"># A completion function for the cd builtin
+<pre class="example-preformatted"># A completion function for the cd builtin
# based on the cd completion function from the bash_completion package
_comp_cd()
{
}
</pre></div>
-<p>We install the completion function using the <samp>-F</samp> option to
-<code>complete</code>:
+<p>We install the completion function using the <samp class="option">-F</samp> option to
+<code class="code">complete</code>:
</p>
<div class="example">
-<pre class="example"># Tell readline to quote appropriate and append slashes to directories;
+<pre class="example-preformatted"># Tell readline to quote appropriate and append slashes to directories;
# use the bash default completion for other arguments
complete -o filenames -o nospace -o bashdefault -F _comp_cd cd
</pre></div>
<p>Since we’d like Bash and Readline to take care of some
of the other details for us, we use several other options to tell Bash
-and Readline what to do. The <samp>-o filenames</samp> option tells Readline
+and Readline what to do.
+The <samp class="option">-o filenames</samp> option tells Readline
that the possible completions should be treated as filenames, and quoted
-appropriately. That option will also cause Readline to append a slash to
+appropriately.
+That option will also cause Readline to append a slash to
filenames it can determine are directories (which is why we might want to
-extend <code>_comp_cd</code> to append a slash if we’re using directories found
-via <var>CDPATH</var>: Readline can’t tell those completions are directories).
-The <samp>-o nospace</samp> option tells Readline to not append a space
+extend <code class="code">_comp_cd</code> to append a slash if we’re using directories found
+via <var class="var">CDPATH</var>: Readline can’t tell those completions are directories).
+The <samp class="option">-o nospace</samp> option tells Readline to not append a space
character to the directory name, in case we want to append to it.
-The <samp>-o bashdefault</samp> option brings in the rest of the "Bash default"
+The <samp class="option">-o bashdefault</samp> option brings in the rest of the "Bash default"
completions – possible completions that Bash adds to the default Readline
-set. These include things like command name completion, variable completion
-for words beginning with ‘<samp>$</samp>’ or ‘<samp>${</samp>’, completions containing pathname
-expansion patterns (see <a href="#Filename-Expansion">Filename Expansion</a>), and so on.
+set.
+These include things like command name completion, variable completion
+for words beginning with ‘<samp class="samp">$</samp>’ or ‘<samp class="samp">${</samp>’, completions containing
+pathname expansion patterns (see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>), and so on.
</p>
-<p>Once installed using <code>complete</code>, <code>_comp_cd</code> will be called every
-time we attempt word completion for a <code>cd</code> command.
+<p>Once installed using <code class="code">complete</code>, <code class="code">_comp_cd</code> will be called every
+time we attempt word completion for a <code class="code">cd</code> command.
</p>
<p>Many more examples – an extensive collection of completions for most of
the common GNU, Unix, and Linux commands – are available as part of the
bash_completion project. This is installed by default on many GNU/Linux
distributions. Originally written by Ian Macdonald, the project now lives
-at <a href="https://github.com/scop/bash-completion/">https://github.com/scop/bash-completion/</a>. There are ports for
-other systems such as Solaris and Mac OS X.
+at <a class="url" href="https://github.com/scop/bash-completion/">https://github.com/scop/bash-completion/</a>.
+There are ports for other systems such as Solaris and Mac OS X.
</p>
<p>An older version of the bash_completion package is distributed with bash
-in the <samp>examples/complete</samp> subdirectory.
+in the <samp class="file">examples/complete</samp> subdirectory.
</p>
-<span id="index-History_002c-how-to-use"></span>
+<a class="index-entry-id" id="index-History_002c-how-to-use"></a>
<hr>
</div>
</div>
-<div class="chapter" id="Using-History-Interactively">
-<div class="header">
+<div class="chapter-level-extent" id="Using-History-Interactively">
+<div class="nav-panel">
<p>
Next: <a href="#Installing-Bash" accesskey="n" rel="next">Installing Bash</a>, Previous: <a href="#Command-Line-Editing" accesskey="p" rel="prev">Command Line Editing</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Using-History-Interactively-1"></span><h2 class="chapter">9 Using History Interactively</h2>
+<h2 class="chapter" id="Using-History-Interactively-1"><span>9 Using History Interactively<a class="copiable-link" href="#Using-History-Interactively-1"> ¶</a></span></h2>
-<p>This chapter describes how to use the <small>GNU</small> History Library
+<p>This chapter describes how to use the <small class="sc">GNU</small> History Library
interactively, from a user’s standpoint.
It should be considered a user’s guide.
-For information on using the <small>GNU</small> History Library in other programs,
-see the <small>GNU</small> Readline Library Manual.
+For information on using the <small class="sc">GNU</small> History Library in other programs,
+see the <small class="sc">GNU</small> Readline Library Manual.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Bash-History-Facilities" accesskey="1">Bash History Facilities</a></li>
<li><a href="#Bash-History-Builtins" accesskey="2">Bash History Builtins</a></li>
<li><a href="#History-Interaction" accesskey="3">History Expansion</a></li>
</ul>
<hr>
-<div class="section" id="Bash-History-Facilities">
-<div class="header">
+<div class="section-level-extent" id="Bash-History-Facilities">
+<div class="nav-panel">
<p>
Next: <a href="#Bash-History-Builtins" accesskey="n" rel="next">Bash History Builtins</a>, Up: <a href="#Using-History-Interactively" accesskey="u" rel="up">Using History Interactively</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-History-Facilities-1"></span><h3 class="section">9.1 Bash History Facilities</h3>
-<span id="index-command-history"></span>
-<span id="index-history-list"></span>
+<h3 class="section" id="Bash-History-Facilities-1"><span>9.1 Bash History Facilities<a class="copiable-link" href="#Bash-History-Facilities-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-command-history"></a>
+<a class="index-entry-id" id="index-history-list"></a>
-<p>When the <samp>-o history</samp> option to the <code>set</code> builtin
-is enabled (see <a href="#The-Set-Builtin">The Set Builtin</a>),
-the shell provides access to the <em>command history</em>,
+<p>When the <samp class="option">-o history</samp> option to the <code class="code">set</code> builtin
+is enabled (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>),
+the shell provides access to the <em class="dfn">command history</em>,
the list of commands previously typed.
-The value of the <code>HISTSIZE</code> shell variable is used as the
+The value of the <code class="env">HISTSIZE</code> shell variable is used as the
number of commands to save in a history list.
-The text of the last <code>$HISTSIZE</code>
+The text of the last <code class="env">$HISTSIZE</code>
commands (default 500) is saved.
The shell stores each command in the history list prior to
parameter and variable expansion
but after history expansion is performed, subject to the
values of the shell variables
-<code>HISTIGNORE</code> and <code>HISTCONTROL</code>.
+<code class="env">HISTIGNORE</code> and <code class="env">HISTCONTROL</code>.
</p>
<p>When the shell starts up, the history is initialized from the
-file named by the <code>HISTFILE</code> variable (default <samp>~/.bash_history</samp>).
-The file named by the value of <code>HISTFILE</code> is truncated, if
+file named by the <code class="env">HISTFILE</code> variable (default <samp class="file">~/.bash_history</samp>).
+The file named by the value of <code class="env">HISTFILE</code> is truncated, if
necessary, to contain no more than the number of lines specified by
-the value of the <code>HISTFILESIZE</code> variable.
+the value of the <code class="env">HISTFILESIZE</code> variable.
When a shell with history enabled exits, the last
-<code>$HISTSIZE</code> lines are copied from the history list to the file
-named by <code>$HISTFILE</code>.
-If the <code>histappend</code> shell option is set (see <a href="#Bash-Builtins">Bash Builtin Commands</a>),
+<code class="env">$HISTSIZE</code> lines are copied from the history list to the file
+named by <code class="env">$HISTFILE</code>.
+If the <code class="code">histappend</code> shell option is set (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>),
the lines are appended to the history file,
otherwise the history file is overwritten.
-If <code>HISTFILE</code> is unset or null,
+If <code class="env">HISTFILE</code> is unset or null,
or if the history file is unwritable, the history is not saved.
After saving the history, the history file is truncated
-to contain no more than <code>$HISTFILESIZE</code> lines.
-If <code>HISTFILESIZE</code> is unset, or set to null, a non-numeric value, or
+to contain no more than <code class="env">$HISTFILESIZE</code> lines.
+If <code class="env">HISTFILESIZE</code> is unset, or set to null, a non-numeric value, or
a numeric value less than zero, the history file is not truncated.
</p>
-<p>If the <code>HISTTIMEFORMAT</code> is set, the time stamp information
+<p>If the <code class="env">HISTTIMEFORMAT</code> is set, the time stamp information
associated with each history entry is written to the history file,
marked with the history comment character.
When the history file is read, lines beginning with the history
comment character followed immediately by a digit are interpreted
as timestamps for the following history entry.
</p>
-<p>The <code>fc</code> builtin command may be used to list or edit and re-execute
+<p>The <code class="code">fc</code> builtin command may be used to list or edit and re-execute
a portion of the history list.
-The <code>history</code> builtin may be used to display or modify the history
+The <code class="code">history</code> builtin may be used to display or modify the history
list and manipulate the history file.
When using command-line editing, search commands
are available in each editing mode that provide access to the
-history list (see <a href="#Commands-For-History">Commands For Manipulating The History</a>).
+history list (see <a class="pxref" href="#Commands-For-History">Commands For Manipulating The History</a>).
</p>
<p>The shell allows control over which commands are saved on the history
list.
-The <code>HISTCONTROL</code> and <code>HISTIGNORE</code>
+The <code class="env">HISTCONTROL</code> and <code class="env">HISTIGNORE</code>
variables are used to cause the shell to save only a subset of the
commands entered.
-The <code>cmdhist</code>
+The <code class="code">cmdhist</code>
shell option, if enabled, causes the shell to attempt to save each
line of a multi-line command in the same history entry, adding
semicolons where necessary to preserve syntactic correctness.
-The <code>lithist</code>
+The <code class="code">lithist</code>
shell option causes the shell to save the command with embedded newlines
instead of semicolons.
-The <code>shopt</code> builtin is used to set these options.
-See <a href="#The-Shopt-Builtin">The Shopt Builtin</a>, for a description of <code>shopt</code>.
+The <code class="code">shopt</code> builtin is used to set these options.
+See <a class="xref" href="#The-Shopt-Builtin">The Shopt Builtin</a>, for a description of <code class="code">shopt</code>.
</p>
<hr>
</div>
-<div class="section" id="Bash-History-Builtins">
-<div class="header">
+<div class="section-level-extent" id="Bash-History-Builtins">
+<div class="nav-panel">
<p>
Next: <a href="#History-Interaction" accesskey="n" rel="next">History Expansion</a>, Previous: <a href="#Bash-History-Facilities" accesskey="p" rel="prev">Bash History Facilities</a>, Up: <a href="#Using-History-Interactively" accesskey="u" rel="up">Using History Interactively</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Bash-History-Builtins-1"></span><h3 class="section">9.2 Bash History Builtins</h3>
-<span id="index-history-builtins"></span>
+<h3 class="section" id="Bash-History-Builtins-1"><span>9.2 Bash History Builtins<a class="copiable-link" href="#Bash-History-Builtins-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-history-builtins"></a>
<p>Bash provides two builtin commands which manipulate the
history list and history file.
</p>
-<dl compact="compact">
-<dt id='index-fc'><span><code>fc</code><a href='#index-fc' class='copiable-anchor'> ¶</a></span></dt>
+<dl class="table">
+<dt><a id="index-fc"></a><span><code class="code">fc</code><a class="copiable-link" href="#index-fc"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example"><code>fc [-e <var>ename</var>] [-lnr] [<var>first</var>] [<var>last</var>]</code>
-<code>fc -s [<var>pat</var>=<var>rep</var>] [<var>command</var>]</code>
+<pre class="example-preformatted"><code class="code">fc [-e <var class="var">ename</var>] [-lnr] [<var class="var">first</var>] [<var class="var">last</var>]</code>
+<code class="code">fc -s [<var class="var">pat</var>=<var class="var">rep</var>] [<var class="var">command</var>]</code>
</pre></div>
-<p>The first form selects a range of commands from <var>first</var> to
-<var>last</var> from the history list and displays or edits and re-executes
+<p>The first form selects a range of commands from <var class="var">first</var> to
+<var class="var">last</var> from the history list and displays or edits and re-executes
them.
-Both <var>first</var> and
-<var>last</var> may be specified as a string (to locate the most recent
+Both <var class="var">first</var> and
+<var class="var">last</var> may be specified as a string (to locate the most recent
command beginning with that string) or as a number (an index into the
history list, where a negative number is used as an offset from the
current command number).
</p>
-<p>When listing, a <var>first</var> or <var>last</var> of 0 is equivalent to -1
-and -0 is equivalent to the current command (usually the <code>fc</code>
+<p>When listing, a <var class="var">first</var> or <var class="var">last</var> of 0 is equivalent to -1
+and -0 is equivalent to the current command (usually the <code class="code">fc</code>
command);
otherwise 0 is equivalent to -1 and -0 is invalid.
</p>
-<p>If <var>last</var> is not specified, it is set to
-<var>first</var>. If <var>first</var> is not specified, it is set to the previous
-command for editing and -16 for listing. If the <samp>-l</samp> flag is
-given, the commands are listed on standard output. The <samp>-n</samp> flag
-suppresses the command numbers when listing. The <samp>-r</samp> flag
+<p>If <var class="var">last</var> is not specified, it is set to
+<var class="var">first</var>. If <var class="var">first</var> is not specified, it is set to the previous
+command for editing and −16 for listing. If the <samp class="option">-l</samp> flag is
+given, the commands are listed on standard output. The <samp class="option">-n</samp> flag
+suppresses the command numbers when listing. The <samp class="option">-r</samp> flag
reverses the order of the listing. Otherwise, the editor given by
-<var>ename</var> is invoked on a file containing those commands. If
-<var>ename</var> is not given, the value of the following variable expansion
-is used: <code>${FCEDIT:-${EDITOR:-vi}}</code>. This says to use the
-value of the <code>FCEDIT</code> variable if set, or the value of the
-<code>EDITOR</code> variable if that is set, or <code>vi</code> if neither is set.
+<var class="var">ename</var> is invoked on a file containing those commands. If
+<var class="var">ename</var> is not given, the value of the following variable expansion
+is used: <code class="code">${FCEDIT:-${EDITOR:-vi}}</code>. This says to use the
+value of the <code class="env">FCEDIT</code> variable if set, or the value of the
+<code class="env">EDITOR</code> variable if that is set, or <code class="code">vi</code> if neither is set.
When editing is complete, the edited commands are echoed and executed.
</p>
-<p>In the second form, <var>command</var> is re-executed after each instance
-of <var>pat</var> in the selected command is replaced by <var>rep</var>.
-<var>command</var> is interpreted the same as <var>first</var> above.
+<p>In the second form, <var class="var">command</var> is re-executed after each instance
+of <var class="var">pat</var> in the selected command is replaced by <var class="var">rep</var>.
+<var class="var">command</var> is interpreted the same as <var class="var">first</var> above.
</p>
-<p>A useful alias to use with the <code>fc</code> command is <code>r='fc -s'</code>, so
-that typing ‘<samp>r cc</samp>’ runs the last command beginning with <code>cc</code>
-and typing ‘<samp>r</samp>’ re-executes the last command (see <a href="#Aliases">Aliases</a>).
+<p>A useful alias to use with the <code class="code">fc</code> command is <code class="code">r='fc -s'</code>, so
+that typing ‘<samp class="samp">r cc</samp>’ runs the last command beginning with <code class="code">cc</code>
+and typing ‘<samp class="samp">r</samp>’ re-executes the last command (see <a class="pxref" href="#Aliases">Aliases</a>).
</p>
</dd>
-<dt id='index-history'><span><code>history</code><a href='#index-history' class='copiable-anchor'> ¶</a></span></dt>
+<dt><a id="index-history"></a><span><code class="code">history</code><a class="copiable-link" href="#index-history"> ¶</a></span></dt>
<dd><div class="example">
-<pre class="example">history [<var>n</var>]
+<pre class="example-preformatted">history [<var class="var">n</var>]
history -c
-history -d <var>offset</var>
-history -d <var>start</var>-<var>end</var>
-history [-anrw] [<var>filename</var>]
-history -ps <var>arg</var>
+history -d <var class="var">offset</var>
+history -d <var class="var">start</var>-<var class="var">end</var>
+history [-anrw] [<var class="var">filename</var>]
+history -ps <var class="var">arg</var>
</pre></div>
<p>With no options, display the history list with line numbers.
-Lines prefixed with a ‘<samp>*</samp>’ have been modified.
-An argument of <var>n</var> lists only the last <var>n</var> lines.
-If the shell variable <code>HISTTIMEFORMAT</code> is set and not null,
-it is used as a format string for <var>strftime</var> to display
+Lines prefixed with a ‘<samp class="samp">*</samp>’ have been modified.
+An argument of <var class="var">n</var> lists only the last <var class="var">n</var> lines.
+If the shell variable <code class="env">HISTTIMEFORMAT</code> is set and not null,
+it is used as a format string for <code class="code">strftime</code>(3) to display
the time stamp associated with each displayed history entry.
No intervening blank is printed between the formatted time stamp
and the history line.
</p>
<p>Options, if supplied, have the following meanings:
</p>
-<dl compact="compact">
-<dt><span><code>-c</code></span></dt>
+<dl class="table">
+<dt><code class="code">-c</code></dt>
<dd><p>Clear the history list. This may be combined
with the other options to replace the history list completely.
</p>
</dd>
-<dt><span><code>-d <var>offset</var></code></span></dt>
-<dd><p>Delete the history entry at position <var>offset</var>.
-If <var>offset</var> is positive, it should be specified as it appears when
+<dt><code class="code">-d <var class="var">offset</var></code></dt>
+<dd><p>Delete the history entry at position <var class="var">offset</var>.
+If <var class="var">offset</var> is positive, it should be specified as it appears when
the history is displayed.
-If <var>offset</var> is negative, it is interpreted as relative to one greater
+If <var class="var">offset</var> is negative, it is interpreted as relative to one greater
than the last history position, so negative indices count back from the
-end of the history, and an index of ‘<samp>-1</samp>’ refers to the current
-<code>history -d</code> command.
+end of the history, and an index of ‘<samp class="samp">-1</samp>’ refers to the current
+<code class="code">history -d</code> command.
</p>
</dd>
-<dt><span><code>-d <var>start</var>-<var>end</var></code></span></dt>
-<dd><p>Delete the range of history entries between positions <var>start</var> and
-<var>end</var>, inclusive.
-Positive and negative values for <var>start</var> and <var>end</var>
+<dt><code class="code">-d <var class="var">start</var>-<var class="var">end</var></code></dt>
+<dd><p>Delete the range of history entries between positions <var class="var">start</var> and
+<var class="var">end</var>, inclusive.
+Positive and negative values for <var class="var">start</var> and <var class="var">end</var>
are interpreted as described above.
</p>
</dd>
-<dt><span><code>-a</code></span></dt>
+<dt><code class="code">-a</code></dt>
<dd><p>Append the new history lines to the history file.
These are history lines entered since the beginning of the current
Bash session, but not already appended to the history file.
</p>
</dd>
-<dt><span><code>-n</code></span></dt>
+<dt><code class="code">-n</code></dt>
<dd><p>Append the history lines not already read from the history file
to the current history list. These are lines appended to the history
file since the beginning of the current Bash session.
</p>
</dd>
-<dt><span><code>-r</code></span></dt>
+<dt><code class="code">-r</code></dt>
<dd><p>Read the history file and append its contents to
the history list.
</p>
</dd>
-<dt><span><code>-w</code></span></dt>
+<dt><code class="code">-w</code></dt>
<dd><p>Write out the current history list to the history file.
</p>
</dd>
-<dt><span><code>-p</code></span></dt>
-<dd><p>Perform history substitution on the <var>arg</var>s and display the result
+<dt><code class="code">-p</code></dt>
+<dd><p>Perform history substitution on the <var class="var">arg</var>s and display the result
on the standard output, without storing the results in the history list.
</p>
</dd>
-<dt><span><code>-s</code></span></dt>
-<dd><p>The <var>arg</var>s are added to the end of
+<dt><code class="code">-s</code></dt>
+<dd><p>The <var class="var">arg</var>s are added to the end of
the history list as a single entry.
</p>
</dd>
</dl>
-<p>If a <var>filename</var> argument is supplied
-when any of the <samp>-w</samp>, <samp>-r</samp>, <samp>-a</samp>, or <samp>-n</samp> options
-is used, Bash uses <var>filename</var> as the history file.
-If not, then the value of the <code>HISTFILE</code> variable is used.
-If <code>HISTFILE</code> is unset or null, these options have no effect.
+<p>If a <var class="var">filename</var> argument is supplied
+when any of the <samp class="option">-w</samp>, <samp class="option">-r</samp>, <samp class="option">-a</samp>, or <samp class="option">-n</samp> options
+is used, Bash uses <var class="var">filename</var> as the history file.
+If not, then the value of the <code class="env">HISTFILE</code> variable is used.
+If <code class="env">HISTFILE</code> is unset or null, these options have no effect.
</p>
<p>The return value is 0 unless an invalid option is encountered, an
error occurs while reading or writing the history file, an invalid
-<var>offset</var> or range is supplied as an argument to <samp>-d</samp>, or the
-history expansion supplied as an argument to <samp>-p</samp> fails.
+<var class="var">offset</var> or range is supplied as an argument to <samp class="option">-d</samp>, or the
+history expansion supplied as an argument to <samp class="option">-p</samp> fails.
</p>
</dd>
</dl>
<hr>
</div>
-<div class="section" id="History-Interaction">
-<div class="header">
+<div class="section-level-extent" id="History-Interaction">
+<div class="nav-panel">
<p>
Previous: <a href="#Bash-History-Builtins" accesskey="p" rel="prev">Bash History Builtins</a>, Up: <a href="#Using-History-Interactively" accesskey="u" rel="up">Using History Interactively</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="History-Expansion"></span><h3 class="section">9.3 History Expansion</h3>
-<span id="index-history-expansion"></span>
+<h3 class="section" id="History-Expansion"><span>9.3 History Expansion<a class="copiable-link" href="#History-Expansion"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-history-expansion"></a>
<p>The History library provides a history expansion feature that is similar
-to the history expansion provided by <code>csh</code>. This section
+to the history expansion provided by <code class="code">csh</code>. This section
describes the syntax used to manipulate the history information.
</p>
<p>History expansions introduce words from the history list into
The second is to select portions of that line for inclusion into the
current one.
</p>
-<p>The line selected from the history is called the <em>event</em>,
-and the portions of that line that are acted upon are called <em>words</em>.
+<p>The line selected from the history is called the <em class="dfn">event</em>,
+and the portions of that line that are acted upon are called <em class="dfn">words</em>.
The line is broken into words in the same fashion
that Bash does, so that several words
surrounded by quotes are considered one word.
-The <em>event designator</em> selects the event, the optional
-<em>word designator</em> selects words from the event, and
-various optional <em>modifiers</em> are available to manipulate the
+The <em class="dfn">event designator</em> selects the event, the optional
+<em class="dfn">word designator</em> selects words from the event, and
+various optional <em class="dfn">modifiers</em> are available to manipulate the
selected words.
</p>
<p>History expansions are introduced by the appearance of the
-history expansion character, which is ‘<samp>!</samp>’ by default.
+history expansion character, which is ‘<samp class="samp">!</samp>’ by default.
History expansions may appear anywhere in the input, but do not nest.
</p>
<p>History expansion implements shell-like quoting conventions:
but single quotes may not, since they are not treated specially within
double quotes.
</p>
-<p>When using the shell, only ‘<samp>\</samp>’ and ‘<samp>'</samp>’ may be used to escape the
+<p>When using the shell, only ‘<samp class="samp">\</samp>’ and ‘<samp class="samp">'</samp>’ may be used to escape the
history expansion character, but the history expansion character is
also treated as quoted if it immediately precedes the closing double quote
in a double-quoted string.
</p>
<p>There is a special abbreviation for substitution, active when the
-<var>quick substitution</var> character (default ‘<samp>^</samp>’)
+<var class="var">quick substitution</var> character (default ‘<samp class="samp">^</samp>’)
is the first character on the line.
It selects the previous history list entry, using an event designator
-equivalent to <code>!!</code>,
+equivalent to <code class="code">!!</code>,
and substitutes one string for another in that line.
-It is described below (see <a href="#Event-Designators">Event Designators</a>).
+It is described below (see <a class="pxref" href="#Event-Designators">Event Designators</a>).
This is the only history expansion that does not begin with the history
expansion character.
</p>
-<p>Several shell options settable with the <code>shopt</code>
-builtin (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>) may be used to tailor
+<p>Several shell options settable with the <code class="code">shopt</code>
+builtin (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>) may be used to tailor
the behavior of history expansion. If the
-<code>histverify</code> shell option is enabled, and Readline
+<code class="code">histverify</code> shell option is enabled, and Readline
is being used, history substitutions are not immediately passed to
the shell parser.
Instead, the expanded line is reloaded into the Readline
editing buffer for further modification.
-If Readline is being used, and the <code>histreedit</code>
+If Readline is being used, and the <code class="code">histreedit</code>
shell option is enabled, a failed history expansion will be
reloaded into the Readline editing buffer for correction.
-The <samp>-p</samp> option to the <code>history</code> builtin command
+The <samp class="option">-p</samp> option to the <code class="code">history</code> builtin command
may be used to see what a history expansion will do before using it.
-The <samp>-s</samp> option to the <code>history</code> builtin may be used to
+The <samp class="option">-s</samp> option to the <code class="code">history</code> builtin may be used to
add commands to the end of the history list without actually executing
them, so that they are available for subsequent recall.
This is most useful in conjunction with Readline.
</p>
<p>The shell allows control of the various characters used by the
-history expansion mechanism with the <code>histchars</code> variable,
-as explained above (see <a href="#Bash-Variables">Bash Variables</a>). The shell uses
+history expansion mechanism with the <code class="code">histchars</code> variable,
+as explained above (see <a class="pxref" href="#Bash-Variables">Bash Variables</a>). The shell uses
the history comment character to mark history timestamps when
writing the history file.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Event-Designators" accesskey="1">Event Designators</a></li>
<li><a href="#Word-Designators" accesskey="2">Word Designators</a></li>
<li><a href="#Modifiers" accesskey="3">Modifiers</a></li>
</ul>
<hr>
-<div class="subsection" id="Event-Designators">
-<div class="header">
+<div class="subsection-level-extent" id="Event-Designators">
+<div class="nav-panel">
<p>
Next: <a href="#Word-Designators" accesskey="n" rel="next">Word Designators</a>, Up: <a href="#History-Interaction" accesskey="u" rel="up">History Expansion</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Event-Designators-1"></span><h4 class="subsection">9.3.1 Event Designators</h4>
-<span id="index-event-designators"></span>
+<h4 class="subsection" id="Event-Designators-1"><span>9.3.1 Event Designators<a class="copiable-link" href="#Event-Designators-1"> ¶</a></span></h4>
+<a class="index-entry-id" id="index-event-designators"></a>
<p>An event designator is a reference to a command line entry in the
history list.
The event designator consists of the portion of the word beginning
with the history expansion character, and ending with the word designator
if one is present, or the end of the word.
-<span id="index-history-events"></span>
+<a class="index-entry-id" id="index-history-events"></a>
</p>
-<dl compact="compact">
-<dt><span><code>!</code></span></dt>
+<dl class="table">
+<dt><code class="code">!</code></dt>
<dd><p>Start a history substitution, except when followed by a space, tab,
-the end of the line, ‘<samp>=</samp>’,
+the end of the line, ‘<samp class="samp">=</samp>’,
or the rest of the shell metacharacters defined above
-(see <a href="#Definitions">Definitions</a>).
+(see <a class="pxref" href="#Definitions">Definitions</a>).
</p>
</dd>
-<dt><span><code>!<var>n</var></code></span></dt>
-<dd><p>Refer to command line <var>n</var>.
+<dt><code class="code">!<var class="var">n</var></code></dt>
+<dd><p>Refer to command line <var class="var">n</var>.
</p>
</dd>
-<dt><span><code>!-<var>n</var></code></span></dt>
-<dd><p>Refer to the command <var>n</var> lines back.
+<dt><code class="code">!-<var class="var">n</var></code></dt>
+<dd><p>Refer to the command <var class="var">n</var> lines back.
</p>
</dd>
-<dt><span><code>!!</code></span></dt>
-<dd><p>Refer to the previous command. This is a synonym for ‘<samp>!-1</samp>’.
+<dt><code class="code">!!</code></dt>
+<dd><p>Refer to the previous command. This is a synonym for ‘<samp class="samp">!-1</samp>’.
</p>
</dd>
-<dt><span><code>!<var>string</var></code></span></dt>
+<dt><code class="code">!<var class="var">string</var></code></dt>
<dd><p>Refer to the most recent command
preceding the current position in the history list
-starting with <var>string</var>.
+starting with <var class="var">string</var>.
</p>
</dd>
-<dt><span><code>!?<var>string</var>[?]</code></span></dt>
+<dt><code class="code">!?<var class="var">string</var>[?]</code></dt>
<dd><p>Refer to the most recent command
preceding the current position in the history list
-containing <var>string</var>.
+containing <var class="var">string</var>.
The trailing
-‘<samp>?</samp>’ may be omitted if the <var>string</var> is followed immediately by
+‘<samp class="samp">?</samp>’ may be omitted if the <var class="var">string</var> is followed immediately by
a newline.
-If <var>string</var> is missing, the string from the most recent search is used;
+If <var class="var">string</var> is missing, the string from the most recent search is used;
it is an error if there is no previous search string.
</p>
</dd>
-<dt><span><code>^<var>string1</var>^<var>string2</var>^</code></span></dt>
-<dd><p>Quick Substitution. Repeat the last command, replacing <var>string1</var>
-with <var>string2</var>. Equivalent to
-<code>!!:s^<var>string1</var>^<var>string2</var>^</code>.
+<dt><code class="code">^<var class="var">string1</var>^<var class="var">string2</var>^</code></dt>
+<dd><p>Quick Substitution. Repeat the last command, replacing <var class="var">string1</var>
+with <var class="var">string2</var>. Equivalent to
+<code class="code">!!:s^<var class="var">string1</var>^<var class="var">string2</var>^</code>.
</p>
</dd>
-<dt><span><code>!#</code></span></dt>
+<dt><code class="code">!#</code></dt>
<dd><p>The entire command line typed so far.
</p>
</dd>
<hr>
</div>
-<div class="subsection" id="Word-Designators">
-<div class="header">
+<div class="subsection-level-extent" id="Word-Designators">
+<div class="nav-panel">
<p>
Next: <a href="#Modifiers" accesskey="n" rel="next">Modifiers</a>, Previous: <a href="#Event-Designators" accesskey="p" rel="prev">Event Designators</a>, Up: <a href="#History-Interaction" accesskey="u" rel="up">History Expansion</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Word-Designators-1"></span><h4 class="subsection">9.3.2 Word Designators</h4>
+<h4 class="subsection" id="Word-Designators-1"><span>9.3.2 Word Designators<a class="copiable-link" href="#Word-Designators-1"> ¶</a></span></h4>
<p>Word designators are used to select desired words from the event.
They are optional; if the word designator isn’t supplied, the history
expansion uses the entire event.
-A ‘<samp>:</samp>’ separates the event specification from the word designator. It
-may be omitted if the word designator begins with a ‘<samp>^</samp>’, ‘<samp>$</samp>’,
-‘<samp>*</samp>’, ‘<samp>-</samp>’, or ‘<samp>%</samp>’. Words are numbered from the beginning
+A ‘<samp class="samp">:</samp>’ separates the event specification from the word designator. It
+may be omitted if the word designator begins with a ‘<samp class="samp">^</samp>’, ‘<samp class="samp">$</samp>’,
+‘<samp class="samp">*</samp>’, ‘<samp class="samp">-</samp>’, or ‘<samp class="samp">%</samp>’. Words are numbered from the beginning
of the line, with the first word being denoted by 0 (zero). Words are
inserted into the current line separated by single spaces.
</p>
<p>For example,
</p>
-<dl compact="compact">
-<dt><span><code>!!</code></span></dt>
+<dl class="table">
+<dt><code class="code">!!</code></dt>
<dd><p>designates the preceding command. When you type this, the preceding
command is repeated in toto.
</p>
</dd>
-<dt><span><code>!!:$</code></span></dt>
+<dt><code class="code">!!:$</code></dt>
<dd><p>designates the last argument of the preceding command. This may be
-shortened to <code>!$</code>.
+shortened to <code class="code">!$</code>.
</p>
</dd>
-<dt><span><code>!fi:2</code></span></dt>
+<dt><code class="code">!fi:2</code></dt>
<dd><p>designates the second argument of the most recent command starting with
-the letters <code>fi</code>.
+the letters <code class="code">fi</code>.
</p></dd>
</dl>
<p>Here are the word designators:
</p>
-<dl compact="compact">
-<dt><span><code>0 (zero)</code></span></dt>
-<dd><p>The <code>0</code>th word. For many applications, this is the command word.
+<dl class="table">
+<dt><code class="code">0 (zero)</code></dt>
+<dd><p>The <code class="code">0</code>th word. For many applications, this is the command word.
</p>
</dd>
-<dt><span><code><var>n</var></code></span></dt>
-<dd><p>The <var>n</var>th word.
+<dt><code class="code"><var class="var">n</var></code></dt>
+<dd><p>The <var class="var">n</var>th word.
</p>
</dd>
-<dt><span><code>^</code></span></dt>
+<dt><code class="code">^</code></dt>
<dd><p>The first argument; that is, word 1.
</p>
</dd>
-<dt><span><code>$</code></span></dt>
+<dt><code class="code">$</code></dt>
<dd><p>The last argument.
</p>
</dd>
-<dt><span><code>%</code></span></dt>
-<dd><p>The first word matched by the most recent ‘<samp>?<var>string</var>?</samp>’ search,
+<dt><code class="code">%</code></dt>
+<dd><p>The first word matched by the most recent ‘<samp class="samp">?<var class="var">string</var>?</samp>’ search,
if the search string begins with a character that is part of a word.
</p>
</dd>
-<dt><span><code><var>x</var>-<var>y</var></code></span></dt>
-<dd><p>A range of words; ‘<samp>-<var>y</var></samp>’ abbreviates ‘<samp>0-<var>y</var></samp>’.
+<dt><code class="code"><var class="var">x</var>-<var class="var">y</var></code></dt>
+<dd><p>A range of words; ‘<samp class="samp">-<var class="var">y</var></samp>’ abbreviates ‘<samp class="samp">0-<var class="var">y</var></samp>’.
</p>
</dd>
-<dt><span><code>*</code></span></dt>
-<dd><p>All of the words, except the <code>0</code>th. This is a synonym for ‘<samp>1-$</samp>’.
-It is not an error to use ‘<samp>*</samp>’ if there is just one word in the event;
+<dt><code class="code">*</code></dt>
+<dd><p>All of the words, except the <code class="code">0</code>th. This is a synonym for ‘<samp class="samp">1-$</samp>’.
+It is not an error to use ‘<samp class="samp">*</samp>’ if there is just one word in the event;
the empty string is returned in that case.
</p>
</dd>
-<dt><span><code><var>x</var>*</code></span></dt>
-<dd><p>Abbreviates ‘<samp><var>x</var>-$</samp>’
+<dt><code class="code"><var class="var">x</var>*</code></dt>
+<dd><p>Abbreviates ‘<samp class="samp"><var class="var">x</var>-$</samp>’
</p>
</dd>
-<dt><span><code><var>x</var>-</code></span></dt>
-<dd><p>Abbreviates ‘<samp><var>x</var>-$</samp>’ like ‘<samp><var>x</var>*</samp>’, but omits the last word.
-If ‘<samp>x</samp>’ is missing, it defaults to 0.
+<dt><code class="code"><var class="var">x</var>-</code></dt>
+<dd><p>Abbreviates ‘<samp class="samp"><var class="var">x</var>-$</samp>’ like ‘<samp class="samp"><var class="var">x</var>*</samp>’, but omits the last word.
+If ‘<samp class="samp">x</samp>’ is missing, it defaults to 0.
</p>
</dd>
</dl>
</p>
<hr>
</div>
-<div class="subsection" id="Modifiers">
-<div class="header">
+<div class="subsection-level-extent" id="Modifiers">
+<div class="nav-panel">
<p>
Previous: <a href="#Word-Designators" accesskey="p" rel="prev">Word Designators</a>, Up: <a href="#History-Interaction" accesskey="u" rel="up">History Expansion</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Modifiers-1"></span><h4 class="subsection">9.3.3 Modifiers</h4>
+<h4 class="subsection" id="Modifiers-1"><span>9.3.3 Modifiers<a class="copiable-link" href="#Modifiers-1"> ¶</a></span></h4>
<p>After the optional word designator, you can add a sequence of one or more
-of the following modifiers, each preceded by a ‘<samp>:</samp>’.
+of the following modifiers, each preceded by a ‘<samp class="samp">:</samp>’.
These modify, or edit, the word or words selected from the history event.
</p>
-<dl compact="compact">
-<dt><span><code>h</code></span></dt>
+<dl class="table">
+<dt><code class="code">h</code></dt>
<dd><p>Remove a trailing pathname component, leaving only the head.
</p>
</dd>
-<dt><span><code>t</code></span></dt>
+<dt><code class="code">t</code></dt>
<dd><p>Remove all leading pathname components, leaving the tail.
</p>
</dd>
-<dt><span><code>r</code></span></dt>
-<dd><p>Remove a trailing suffix of the form ‘<samp>.<var>suffix</var></samp>’, leaving
+<dt><code class="code">r</code></dt>
+<dd><p>Remove a trailing suffix of the form ‘<samp class="samp">.<var class="var">suffix</var></samp>’, leaving
the basename.
</p>
</dd>
-<dt><span><code>e</code></span></dt>
+<dt><code class="code">e</code></dt>
<dd><p>Remove all but the trailing suffix.
</p>
</dd>
-<dt><span><code>p</code></span></dt>
+<dt><code class="code">p</code></dt>
<dd><p>Print the new command but do not execute it.
</p>
</dd>
-<dt><span><code>q</code></span></dt>
+<dt><code class="code">q</code></dt>
<dd><p>Quote the substituted words, escaping further substitutions.
</p>
</dd>
-<dt><span><code>x</code></span></dt>
-<dd><p>Quote the substituted words as with ‘<samp>q</samp>’,
+<dt><code class="code">x</code></dt>
+<dd><p>Quote the substituted words as with ‘<samp class="samp">q</samp>’,
but break into words at spaces, tabs, and newlines.
-The ‘<samp>q</samp>’ and ‘<samp>x</samp>’ modifiers are mutually exclusive; the last one
+The ‘<samp class="samp">q</samp>’ and ‘<samp class="samp">x</samp>’ modifiers are mutually exclusive; the last one
supplied is used.
</p>
</dd>
-<dt><span><code>s/<var>old</var>/<var>new</var>/</code></span></dt>
-<dd><p>Substitute <var>new</var> for the first occurrence of <var>old</var> in the
+<dt><code class="code">s/<var class="var">old</var>/<var class="var">new</var>/</code></dt>
+<dd><p>Substitute <var class="var">new</var> for the first occurrence of <var class="var">old</var> in the
event line.
-Any character may be used as the delimiter in place of ‘<samp>/</samp>’.
-The delimiter may be quoted in <var>old</var> and <var>new</var>
-with a single backslash. If ‘<samp>&</samp>’ appears in <var>new</var>,
-it is replaced by <var>old</var>. A single backslash will quote
-the ‘<samp>&</samp>’.
-If <var>old</var> is null, it is set to the last <var>old</var>
+Any character may be used as the delimiter in place of ‘<samp class="samp">/</samp>’.
+The delimiter may be quoted in <var class="var">old</var> and <var class="var">new</var>
+with a single backslash. If ‘<samp class="samp">&</samp>’ appears in <var class="var">new</var>,
+it is replaced by <var class="var">old</var>. A single backslash will quote
+the ‘<samp class="samp">&</samp>’.
+If <var class="var">old</var> is null, it is set to the last <var class="var">old</var>
substituted, or, if no previous history substitutions took place,
-the last <var>string</var>
-in a !?<var>string</var><code>[?]</code>
+the last <var class="var">string</var>
+in a !?<var class="var">string</var><code class="code">[?]</code>
search.
-If <var>new</var> is null, each matching <var>old</var> is deleted.
+If <var class="var">new</var> is null, each matching <var class="var">old</var> is deleted.
The final delimiter is optional if it is the last
character on the input line.
</p>
</dd>
-<dt><span><code>&</code></span></dt>
+<dt><code class="code">&</code></dt>
<dd><p>Repeat the previous substitution.
</p>
</dd>
-<dt><span><code>g</code></span></dt>
-<dt><span><code>a</code></span></dt>
+<dt><code class="code">g</code></dt>
+<dt><code class="code">a</code></dt>
<dd><p>Cause changes to be applied over the entire event line. Used in
-conjunction with ‘<samp>s</samp>’, as in <code>gs/<var>old</var>/<var>new</var>/</code>,
-or with ‘<samp>&</samp>’.
+conjunction with ‘<samp class="samp">s</samp>’, as in <code class="code">gs/<var class="var">old</var>/<var class="var">new</var>/</code>,
+or with ‘<samp class="samp">&</samp>’.
</p>
</dd>
-<dt><span><code>G</code></span></dt>
-<dd><p>Apply the following ‘<samp>s</samp>’ or ‘<samp>&</samp>’ modifier once to each word
+<dt><code class="code">G</code></dt>
+<dd><p>Apply the following ‘<samp class="samp">s</samp>’ or ‘<samp class="samp">&</samp>’ modifier once to each word
in the event.
</p>
</dd>
</div>
</div>
</div>
-<div class="chapter" id="Installing-Bash">
-<div class="header">
+<div class="chapter-level-extent" id="Installing-Bash">
+<div class="nav-panel">
<p>
Next: <a href="#Reporting-Bugs" accesskey="n" rel="next">Reporting Bugs</a>, Previous: <a href="#Using-History-Interactively" accesskey="p" rel="prev">Using History Interactively</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Installing-Bash-1"></span><h2 class="chapter">10 Installing Bash</h2>
+<h2 class="chapter" id="Installing-Bash-1"><span>10 Installing Bash<a class="copiable-link" href="#Installing-Bash-1"> ¶</a></span></h2>
<p>This chapter provides basic instructions for installing Bash on
the various supported platforms. The distribution supports the
-<small>GNU</small> operating systems, nearly every version of Unix, and several
+<small class="sc">GNU</small> operating systems, nearly every version of Unix, and several
non-Unix systems such as BeOS and Interix.
Other independent ports exist for
-<small>MS-DOS</small>, <small>OS/2</small>, and Windows platforms.
+<small class="sc">MS-DOS</small>, <small class="sc">OS/2</small>, and Windows platforms.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Basic-Installation" accesskey="1">Basic Installation</a></li>
<li><a href="#Compilers-and-Options" accesskey="2">Compilers and Options</a></li>
<li><a href="#Compiling-For-Multiple-Architectures" accesskey="3">Compiling For Multiple Architectures</a></li>
<li><a href="#Optional-Features" accesskey="8">Optional Features</a></li>
</ul>
<hr>
-<div class="section" id="Basic-Installation">
-<div class="header">
+<div class="section-level-extent" id="Basic-Installation">
+<div class="nav-panel">
<p>
Next: <a href="#Compilers-and-Options" accesskey="n" rel="next">Compilers and Options</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Basic-Installation-1"></span><h3 class="section">10.1 Basic Installation</h3>
-<span id="index-installation"></span>
-<span id="index-configuration"></span>
-<span id="index-Bash-installation"></span>
-<span id="index-Bash-configuration"></span>
+<h3 class="section" id="Basic-Installation-1"><span>10.1 Basic Installation<a class="copiable-link" href="#Basic-Installation-1"> ¶</a></span></h3>
+<a class="index-entry-id" id="index-installation"></a>
+<a class="index-entry-id" id="index-configuration"></a>
+<a class="index-entry-id" id="index-Bash-installation"></a>
+<a class="index-entry-id" id="index-Bash-configuration"></a>
<p>These are installation instructions for Bash.
</p>
<p>The simplest way to compile Bash is:
</p>
-<ol>
-<li> <code>cd</code> to the directory containing the source code and type
-‘<samp>./configure</samp>’ to configure Bash for your system. If you’re
-using <code>csh</code> on an old version of System V, you might need to
-type ‘<samp>sh ./configure</samp>’ instead to prevent <code>csh</code> from trying
-to execute <code>configure</code> itself.
+<ol class="enumerate">
+<li> <code class="code">cd</code> to the directory containing the source code and type
+‘<samp class="samp">./configure</samp>’ to configure Bash for your system. If you’re
+using <code class="code">csh</code> on an old version of System V, you might need to
+type ‘<samp class="samp">sh ./configure</samp>’ instead to prevent <code class="code">csh</code> from trying
+to execute <code class="code">configure</code> itself.
-<p>Running <code>configure</code> takes some time.
+<p>Running <code class="code">configure</code> takes some time.
While running, it prints messages telling which features it is
checking for.
</p>
-</li><li> Type ‘<samp>make</samp>’ to compile Bash and build the <code>bashbug</code> bug
+</li><li> Type ‘<samp class="samp">make</samp>’ to compile Bash and build the <code class="code">bashbug</code> bug
reporting script.
-</li><li> Optionally, type ‘<samp>make tests</samp>’ to run the Bash test suite.
+</li><li> Optionally, type ‘<samp class="samp">make tests</samp>’ to run the Bash test suite.
-</li><li> Type ‘<samp>make install</samp>’ to install <code>bash</code> and <code>bashbug</code>.
+</li><li> Type ‘<samp class="samp">make install</samp>’ to install <code class="code">bash</code> and <code class="code">bashbug</code>.
This will also install the manual pages and Info file, message translation
files, some supplemental documentation, a number of example loadable
builtin commands, and a set of header files for developing loadable
builtins.
-You may need additional privileges to install <code>bash</code> to your
-desired destination, so ‘<samp>sudo make install</samp>’ might be required.
-More information about controlling the locations where <code>bash</code> and
-other files are installed is below (see <a href="#Installation-Names">Installation Names</a>).
+You may need additional privileges to install <code class="code">bash</code> to your
+desired destination, so ‘<samp class="samp">sudo make install</samp>’ might be required.
+More information about controlling the locations where <code class="code">bash</code> and
+other files are installed is below (see <a class="pxref" href="#Installation-Names">Installation Names</a>).
</li></ol>
-<p>The <code>configure</code> shell script attempts to guess correct
+<p>The <code class="code">configure</code> shell script attempts to guess correct
values for various system-dependent variables used during
-compilation. It uses those values to create a <samp>Makefile</samp> in
+compilation. It uses those values to create a <samp class="file">Makefile</samp> in
each directory of the package (the top directory, the
-<samp>builtins</samp>, <samp>doc</samp>, <samp>po</samp>, and <samp>support</samp> directories,
-each directory under <samp>lib</samp>, and several others). It also creates a
-<samp>config.h</samp> file containing system-dependent definitions.
-Finally, it creates a shell script named <code>config.status</code> that you
+<samp class="file">builtins</samp>, <samp class="file">doc</samp>, <samp class="file">po</samp>, and <samp class="file">support</samp> directories,
+each directory under <samp class="file">lib</samp>, and several others). It also creates a
+<samp class="file">config.h</samp> file containing system-dependent definitions.
+Finally, it creates a shell script named <code class="code">config.status</code> that you
can run in the future to recreate the current configuration, a
-file <samp>config.cache</samp> that saves the results of its tests to
-speed up reconfiguring, and a file <samp>config.log</samp> containing
-compiler output (useful mainly for debugging <code>configure</code>).
+file <samp class="file">config.cache</samp> that saves the results of its tests to
+speed up reconfiguring, and a file <samp class="file">config.log</samp> containing
+compiler output (useful mainly for debugging <code class="code">configure</code>).
If at some point
-<samp>config.cache</samp> contains results you don’t want to keep, you
+<samp class="file">config.cache</samp> contains results you don’t want to keep, you
may remove or edit it.
</p>
<p>To find out more about the options and arguments that the
-<code>configure</code> script understands, type
+<code class="code">configure</code> script understands, type
</p>
<div class="example">
-<pre class="example">bash-4.2$ ./configure --help
+<pre class="example-preformatted">bash-4.2$ ./configure --help
</pre></div>
<p>at the Bash prompt in your Bash source directory.
<p>If you want to build Bash in a directory separate from the source
directory – to build for multiple architectures, for example –
just use the full path to the configure script. The following commands
-will build Bash in a directory under <samp>/usr/local/build</samp> from
-the source code in <samp>/usr/local/src/bash-4.4</samp>:
+will build Bash in a directory under <samp class="file">/usr/local/build</samp> from
+the source code in <samp class="file">/usr/local/src/bash-4.4</samp>:
</p>
<div class="example">
-<pre class="example">mkdir /usr/local/build/bash-4.4
+<pre class="example-preformatted">mkdir /usr/local/build/bash-4.4
cd /usr/local/build/bash-4.4
bash /usr/local/src/bash-4.4/configure
make
</pre></div>
-<p>See <a href="#Compiling-For-Multiple-Architectures">Compiling For Multiple Architectures</a> for more information
+<p>See <a class="ref" href="#Compiling-For-Multiple-Architectures">Compiling For Multiple Architectures</a> for more information
about building in a directory separate from the source.
</p>
<p>If you need to do unusual things to compile Bash, please
-try to figure out how <code>configure</code> could check whether or not
+try to figure out how <code class="code">configure</code> could check whether or not
to do them, and mail diffs or instructions to
-<a href="mailto:bash-maintainers@gnu.org">bash-maintainers@gnu.org</a> so they can be
+<a class="email" href="mailto:bash-maintainers@gnu.org">bash-maintainers@gnu.org</a> so they can be
considered for the next release.
</p>
-<p>The file <samp>configure.ac</samp> is used to create <code>configure</code>
+<p>The file <samp class="file">configure.ac</samp> is used to create <code class="code">configure</code>
by a program called Autoconf.
-You only need <samp>configure.ac</samp> if you want to change it or regenerate
-<code>configure</code> using a newer version of Autoconf.
+You only need <samp class="file">configure.ac</samp> if you want to change it or regenerate
+<code class="code">configure</code> using a newer version of Autoconf.
If you do this, make sure you are using Autoconf version 2.69 or
newer.
</p>
<p>You can remove the program binaries and object files from the
-source code directory by typing ‘<samp>make clean</samp>’. To also remove the
-files that <code>configure</code> created (so you can compile Bash for
-a different kind of computer), type ‘<samp>make distclean</samp>’.
+source code directory by typing ‘<samp class="samp">make clean</samp>’. To also remove the
+files that <code class="code">configure</code> created (so you can compile Bash for
+a different kind of computer), type ‘<samp class="samp">make distclean</samp>’.
</p>
<hr>
</div>
-<div class="section" id="Compilers-and-Options">
-<div class="header">
+<div class="section-level-extent" id="Compilers-and-Options">
+<div class="nav-panel">
<p>
Next: <a href="#Compiling-For-Multiple-Architectures" accesskey="n" rel="next">Compiling For Multiple Architectures</a>, Previous: <a href="#Basic-Installation" accesskey="p" rel="prev">Basic Installation</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Compilers-and-Options-1"></span><h3 class="section">10.2 Compilers and Options</h3>
+<h3 class="section" id="Compilers-and-Options-1"><span>10.2 Compilers and Options<a class="copiable-link" href="#Compilers-and-Options-1"> ¶</a></span></h3>
<p>Some systems require unusual options for compilation or linking
-that the <code>configure</code> script does not know about. You can
-give <code>configure</code> initial values for variables by setting
+that the <code class="code">configure</code> script does not know about. You can
+give <code class="code">configure</code> initial values for variables by setting
them in the environment. Using a Bourne-compatible shell, you
can do that on the command line like this:
</p>
<div class="example">
-<pre class="example">CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure
+<pre class="example-preformatted">CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure
</pre></div>
-<p>On systems that have the <code>env</code> program, you can do it like this:
+<p>On systems that have the <code class="code">env</code> program, you can do it like this:
</p>
<div class="example">
-<pre class="example">env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure
+<pre class="example-preformatted">env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure
</pre></div>
<p>The configuration process uses GCC to build Bash if it
</p>
<hr>
</div>
-<div class="section" id="Compiling-For-Multiple-Architectures">
-<div class="header">
+<div class="section-level-extent" id="Compiling-For-Multiple-Architectures">
+<div class="nav-panel">
<p>
Next: <a href="#Installation-Names" accesskey="n" rel="next">Installation Names</a>, Previous: <a href="#Compilers-and-Options" accesskey="p" rel="prev">Compilers and Options</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Compiling-For-Multiple-Architectures-1"></span><h3 class="section">10.3 Compiling For Multiple Architectures</h3>
+<h3 class="section" id="Compiling-For-Multiple-Architectures-1"><span>10.3 Compiling For Multiple Architectures<a class="copiable-link" href="#Compiling-For-Multiple-Architectures-1"> ¶</a></span></h3>
<p>You can compile Bash for more than one kind of computer at the
same time, by placing the object files for each architecture in their
-own directory. To do this, you must use a version of <code>make</code> that
-supports the <code>VPATH</code> variable, such as GNU <code>make</code>.
-<code>cd</code> to the
+own directory. To do this, you must use a version of <code class="code">make</code> that
+supports the <code class="code">VPATH</code> variable, such as GNU <code class="code">make</code>.
+<code class="code">cd</code> to the
directory where you want the object files and executables to go and run
-the <code>configure</code> script from the source directory
-(see <a href="#Basic-Installation">Basic Installation</a>).
+the <code class="code">configure</code> script from the source directory
+(see <a class="pxref" href="#Basic-Installation">Basic Installation</a>).
You may need to
-supply the <samp>--srcdir=PATH</samp> argument to tell <code>configure</code> where the
-source files are. <code>configure</code> automatically checks for the
-source code in the directory that <code>configure</code> is in and in ‘..’.
+supply the <samp class="option">--srcdir=PATH</samp> argument to tell <code class="code">configure</code> where the
+source files are. <code class="code">configure</code> automatically checks for the
+source code in the directory that <code class="code">configure</code> is in and in ‘..’.
</p>
-<p>If you have to use a <code>make</code> that does not support the <code>VPATH</code>
+<p>If you have to use a <code class="code">make</code> that does not support the <code class="code">VPATH</code>
variable, you can compile Bash for one architecture at a
time in the source code directory. After you have installed
-Bash for one architecture, use ‘<samp>make distclean</samp>’ before
+Bash for one architecture, use ‘<samp class="samp">make distclean</samp>’ before
reconfiguring for another architecture.
</p>
<p>Alternatively, if your system supports symbolic links, you can use the
-<samp>support/mkclone</samp> script to create a build tree which has
+<samp class="file">support/mkclone</samp> script to create a build tree which has
symbolic links back to each file in the source directory. Here’s an
example that creates a build directory in the current directory from a
-source directory <samp>/usr/gnu/src/bash-2.0</samp>:
+source directory <samp class="file">/usr/gnu/src/bash-2.0</samp>:
</p>
<div class="example">
-<pre class="example">bash /usr/gnu/src/bash-2.0/support/mkclone -s /usr/gnu/src/bash-2.0 .
+<pre class="example-preformatted">bash /usr/gnu/src/bash-2.0/support/mkclone -s /usr/gnu/src/bash-2.0 .
</pre></div>
-<p>The <code>mkclone</code> script requires Bash, so you must have already built
+<p>The <code class="code">mkclone</code> script requires Bash, so you must have already built
Bash for at least one architecture before you can create build
directories for other architectures.
</p>
<hr>
</div>
-<div class="section" id="Installation-Names">
-<div class="header">
+<div class="section-level-extent" id="Installation-Names">
+<div class="nav-panel">
<p>
Next: <a href="#Specifying-the-System-Type" accesskey="n" rel="next">Specifying the System Type</a>, Previous: <a href="#Compiling-For-Multiple-Architectures" accesskey="p" rel="prev">Compiling For Multiple Architectures</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Installation-Names-1"></span><h3 class="section">10.4 Installation Names</h3>
-
-<p>By default, ‘<samp>make install</samp>’ will install into
-<samp>/usr/local/bin</samp>, <samp>/usr/local/man</samp>, etc.;
-that is, the <em>installation prefix</em> defaults to <samp>/usr/local</samp>.
-You can specify an installation prefix other than <samp>/usr/local</samp> by
-giving <code>configure</code> the option <samp>--prefix=<var>PATH</var></samp>,
-or by specifying a value for the <code>prefix</code> ‘<samp>make</samp>’
-variable when running ‘<samp>make install</samp>’
-(e.g., ‘<samp>make install prefix=<var>PATH</var></samp>’).
-The <code>prefix</code> variable provides a default for <code>exec_prefix</code> and
+<h3 class="section" id="Installation-Names-1"><span>10.4 Installation Names<a class="copiable-link" href="#Installation-Names-1"> ¶</a></span></h3>
+
+<p>By default, ‘<samp class="samp">make install</samp>’ will install into
+<samp class="file">/usr/local/bin</samp>, <samp class="file">/usr/local/man</samp>, etc.;
+that is, the <em class="dfn">installation prefix</em> defaults to <samp class="file">/usr/local</samp>.
+You can specify an installation prefix other than <samp class="file">/usr/local</samp> by
+giving <code class="code">configure</code> the option <samp class="option">--prefix=<var class="var">PATH</var></samp>,
+or by specifying a value for the <code class="env">prefix</code> ‘<samp class="samp">make</samp>’
+variable when running ‘<samp class="samp">make install</samp>’
+(e.g., ‘<samp class="samp">make install prefix=<var class="var">PATH</var></samp>’).
+The <code class="env">prefix</code> variable provides a default for <code class="env">exec_prefix</code> and
other variables used when installing Bash.
</p>
<p>You can specify separate installation prefixes for
architecture-specific files and architecture-independent files.
-If you give <code>configure</code> the option
-<samp>--exec-prefix=<var>PATH</var></samp>, ‘<samp>make install</samp>’ will use
-<var>PATH</var> as the prefix for installing programs and libraries.
+If you give <code class="code">configure</code> the option
+<samp class="option">--exec-prefix=<var class="var">PATH</var></samp>, ‘<samp class="samp">make install</samp>’ will use
+<var class="var">PATH</var> as the prefix for installing programs and libraries.
Documentation and other data files will still use the regular prefix.
</p>
<p>If you would like to change the installation locations for a single run,
-you can specify these variables as arguments to <code>make</code>:
-‘<samp>make install exec_prefix=/</samp>’ will install <code>bash</code> and
-<code>bashbug</code> into <samp>/bin</samp> instead of the default <samp>/usr/local/bin</samp>.
+you can specify these variables as arguments to <code class="code">make</code>:
+‘<samp class="samp">make install exec_prefix=/</samp>’ will install <code class="code">bash</code> and
+<code class="code">bashbug</code> into <samp class="file">/bin</samp> instead of the default <samp class="file">/usr/local/bin</samp>.
</p>
<p>If you want to see the files Bash will install and where it will install
them without changing anything on your system, specify the variable
-<code>DESTDIR</code> as an argument to <code>make</code>. Its value should be the
+<code class="env">DESTDIR</code> as an argument to <code class="code">make</code>. Its value should be the
absolute directory path you’d like to use as the root of your sample
installation tree. For example,
</p>
<div class="example">
-<pre class="example">mkdir /fs1/bash-install
+<pre class="example-preformatted">mkdir /fs1/bash-install
make install DESTDIR=/fs1/bash-install
</pre></div>
-<p>will install <code>bash</code> into <samp>/fs1/bash-install/usr/local/bin/bash</samp>,
+<p>will install <code class="code">bash</code> into <samp class="file">/fs1/bash-install/usr/local/bin/bash</samp>,
the documentation into directories within
-<samp>/fs1/bash-install/usr/local/share</samp>, the example loadable builtins into
-<samp>/fs1/bash-install/usr/local/lib/bash</samp>, and so on.
-You can use the usual <code>exec_prefix</code> and <code>prefix</code> variables to alter
-the directory paths beneath the value of <code>DESTDIR</code>.
+<samp class="file">/fs1/bash-install/usr/local/share</samp>, the example loadable builtins into
+<samp class="file">/fs1/bash-install/usr/local/lib/bash</samp>, and so on.
+You can use the usual <code class="env">exec_prefix</code> and <code class="env">prefix</code> variables to alter
+the directory paths beneath the value of <code class="env">DESTDIR</code>.
</p>
<p>The GNU Makefile standards provide a more complete description of these
variables and their effects.
</p>
<hr>
</div>
-<div class="section" id="Specifying-the-System-Type">
-<div class="header">
+<div class="section-level-extent" id="Specifying-the-System-Type">
+<div class="nav-panel">
<p>
Next: <a href="#Sharing-Defaults" accesskey="n" rel="next">Sharing Defaults</a>, Previous: <a href="#Installation-Names" accesskey="p" rel="prev">Installation Names</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Specifying-the-System-Type-1"></span><h3 class="section">10.5 Specifying the System Type</h3>
+<h3 class="section" id="Specifying-the-System-Type-1"><span>10.5 Specifying the System Type<a class="copiable-link" href="#Specifying-the-System-Type-1"> ¶</a></span></h3>
-<p>There may be some features <code>configure</code> can not figure out
+<p>There may be some features <code class="code">configure</code> can not figure out
automatically, but needs to determine by the type of host Bash
-will run on. Usually <code>configure</code> can figure that
+will run on. Usually <code class="code">configure</code> can figure that
out, but if it prints a message saying it can not guess the host
-type, give it the <samp>--host=TYPE</samp> option. ‘<samp>TYPE</samp>’ can
-either be a short name for the system type, such as ‘<samp>sun4</samp>’,
-or a canonical name with three fields: ‘<samp>CPU-COMPANY-SYSTEM</samp>’
-(e.g., ‘<samp>i386-unknown-freebsd4.2</samp>’).
+type, give it the <samp class="option">--host=TYPE</samp> option. ‘<samp class="samp">TYPE</samp>’ can
+either be a short name for the system type, such as ‘<samp class="samp">sun4</samp>’,
+or a canonical name with three fields: ‘<samp class="samp">CPU-COMPANY-SYSTEM</samp>’
+(e.g., ‘<samp class="samp">i386-unknown-freebsd4.2</samp>’).
</p>
-<p>See the file <samp>support/config.sub</samp> for the possible
+<p>See the file <samp class="file">support/config.sub</samp> for the possible
values of each field.
</p>
<hr>
</div>
-<div class="section" id="Sharing-Defaults">
-<div class="header">
+<div class="section-level-extent" id="Sharing-Defaults">
+<div class="nav-panel">
<p>
Next: <a href="#Operation-Controls" accesskey="n" rel="next">Operation Controls</a>, Previous: <a href="#Specifying-the-System-Type" accesskey="p" rel="prev">Specifying the System Type</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Sharing-Defaults-1"></span><h3 class="section">10.6 Sharing Defaults</h3>
+<h3 class="section" id="Sharing-Defaults-1"><span>10.6 Sharing Defaults<a class="copiable-link" href="#Sharing-Defaults-1"> ¶</a></span></h3>
-<p>If you want to set default values for <code>configure</code> scripts to
+<p>If you want to set default values for <code class="code">configure</code> scripts to
share, you can create a site shell script called
-<code>config.site</code> that gives default values for variables like
-<code>CC</code>, <code>cache_file</code>, and <code>prefix</code>. <code>configure</code>
-looks for <samp>PREFIX/share/config.site</samp> if it exists, then
-<samp>PREFIX/etc/config.site</samp> if it exists. Or, you can set the
-<code>CONFIG_SITE</code> environment variable to the location of the site
-script. A warning: the Bash <code>configure</code> looks for a site script,
-but not all <code>configure</code> scripts do.
+<code class="code">config.site</code> that gives default values for variables like
+<code class="code">CC</code>, <code class="code">cache_file</code>, and <code class="code">prefix</code>. <code class="code">configure</code>
+looks for <samp class="file">PREFIX/share/config.site</samp> if it exists, then
+<samp class="file">PREFIX/etc/config.site</samp> if it exists. Or, you can set the
+<code class="code">CONFIG_SITE</code> environment variable to the location of the site
+script. A warning: the Bash <code class="code">configure</code> looks for a site script,
+but not all <code class="code">configure</code> scripts do.
</p>
<hr>
</div>
-<div class="section" id="Operation-Controls">
-<div class="header">
+<div class="section-level-extent" id="Operation-Controls">
+<div class="nav-panel">
<p>
Next: <a href="#Optional-Features" accesskey="n" rel="next">Optional Features</a>, Previous: <a href="#Sharing-Defaults" accesskey="p" rel="prev">Sharing Defaults</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Operation-Controls-1"></span><h3 class="section">10.7 Operation Controls</h3>
+<h3 class="section" id="Operation-Controls-1"><span>10.7 Operation Controls<a class="copiable-link" href="#Operation-Controls-1"> ¶</a></span></h3>
-<p><code>configure</code> recognizes the following options to control how it
+<p><code class="code">configure</code> recognizes the following options to control how it
operates.
</p>
-<dl compact="compact">
-<dt><span><code>--cache-file=<var>file</var></code></span></dt>
+<dl class="table">
+<dt><code class="code">--cache-file=<var class="var">file</var></code></dt>
<dd><p>Use and save the results of the tests in
-<var>file</var> instead of <samp>./config.cache</samp>. Set <var>file</var> to
-<samp>/dev/null</samp> to disable caching, for debugging
-<code>configure</code>.
+<var class="var">file</var> instead of <samp class="file">./config.cache</samp>. Set <var class="var">file</var> to
+<samp class="file">/dev/null</samp> to disable caching, for debugging
+<code class="code">configure</code>.
</p>
</dd>
-<dt><span><code>--help</code></span></dt>
-<dd><p>Print a summary of the options to <code>configure</code>, and exit.
+<dt><code class="code">--help</code></dt>
+<dd><p>Print a summary of the options to <code class="code">configure</code>, and exit.
</p>
</dd>
-<dt><span><code>--quiet</code></span></dt>
-<dt><span><code>--silent</code></span></dt>
-<dt><span><code>-q</code></span></dt>
+<dt><code class="code">--quiet</code></dt>
+<dt><code class="code">--silent</code></dt>
+<dt><code class="code">-q</code></dt>
<dd><p>Do not print messages saying which checks are being made.
</p>
</dd>
-<dt><span><code>--srcdir=<var>dir</var></code></span></dt>
-<dd><p>Look for the Bash source code in directory <var>dir</var>. Usually
-<code>configure</code> can determine that directory automatically.
+<dt><code class="code">--srcdir=<var class="var">dir</var></code></dt>
+<dd><p>Look for the Bash source code in directory <var class="var">dir</var>. Usually
+<code class="code">configure</code> can determine that directory automatically.
</p>
</dd>
-<dt><span><code>--version</code></span></dt>
-<dd><p>Print the version of Autoconf used to generate the <code>configure</code>
+<dt><code class="code">--version</code></dt>
+<dd><p>Print the version of Autoconf used to generate the <code class="code">configure</code>
script, and exit.
</p></dd>
</dl>
-<p><code>configure</code> also accepts some other, not widely used, boilerplate
-options. ‘<samp>configure --help</samp>’ prints the complete list.
+<p><code class="code">configure</code> also accepts some other, not widely used, boilerplate
+options. ‘<samp class="samp">configure --help</samp>’ prints the complete list.
</p>
<hr>
</div>
-<div class="section" id="Optional-Features">
-<div class="header">
+<div class="section-level-extent" id="Optional-Features">
+<div class="nav-panel">
<p>
Previous: <a href="#Operation-Controls" accesskey="p" rel="prev">Operation Controls</a>, Up: <a href="#Installing-Bash" accesskey="u" rel="up">Installing Bash</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Optional-Features-1"></span><h3 class="section">10.8 Optional Features</h3>
+<h3 class="section" id="Optional-Features-1"><span>10.8 Optional Features<a class="copiable-link" href="#Optional-Features-1"> ¶</a></span></h3>
-<p>The Bash <code>configure</code> has a number of <samp>--enable-<var>feature</var></samp>
-options, where <var>feature</var> indicates an optional part of Bash.
-There are also several <samp>--with-<var>package</var></samp> options,
-where <var>package</var> is something like ‘<samp>bash-malloc</samp>’ or ‘<samp>purify</samp>’.
+<p>The Bash <code class="code">configure</code> has a number of <samp class="option">--enable-<var class="var">feature</var></samp>
+options, where <var class="var">feature</var> indicates an optional part of Bash.
+There are also several <samp class="option">--with-<var class="var">package</var></samp> options,
+where <var class="var">package</var> is something like ‘<samp class="samp">bash-malloc</samp>’ or ‘<samp class="samp">purify</samp>’.
To turn off the default use of a package, use
-<samp>--without-<var>package</var></samp>. To configure Bash without a feature
-that is enabled by default, use <samp>--disable-<var>feature</var></samp>.
+<samp class="option">--without-<var class="var">package</var></samp>. To configure Bash without a feature
+that is enabled by default, use <samp class="option">--disable-<var class="var">feature</var></samp>.
</p>
-<p>Here is a complete list of the <samp>--enable-</samp> and
-<samp>--with-</samp> options that the Bash <code>configure</code> recognizes.
+<p>Here is a complete list of the <samp class="option">--enable-</samp> and
+<samp class="option">--with-</samp> options that the Bash <code class="code">configure</code> recognizes.
</p>
-<dl compact="compact">
-<dt><span><code>--with-afs</code></span></dt>
+<dl class="table">
+<dt><code class="code">--with-afs</code></dt>
<dd><p>Define if you are using the Andrew File System from Transarc.
</p>
</dd>
-<dt><span><code>--with-bash-malloc</code></span></dt>
+<dt><code class="code">--with-bash-malloc</code></dt>
<dd><p>Use the Bash version of
-<code>malloc</code> in the directory <samp>lib/malloc</samp>. This is not the same
-<code>malloc</code> that appears in <small>GNU</small> libc, but an older version
-originally derived from the 4.2 <small>BSD</small> <code>malloc</code>. This <code>malloc</code>
+<code class="code">malloc</code> in the directory <samp class="file">lib/malloc</samp>. This is not the same
+<code class="code">malloc</code> that appears in <small class="sc">GNU</small> libc, but an older version
+originally derived from the 4.2 <small class="sc">BSD</small> <code class="code">malloc</code>. This <code class="code">malloc</code>
is very fast, but wastes some space on each allocation.
This option is enabled by default.
-The <samp>NOTES</samp> file contains a list of systems for
-which this should be turned off, and <code>configure</code> disables this
+The <samp class="file">NOTES</samp> file contains a list of systems for
+which this should be turned off, and <code class="code">configure</code> disables this
option automatically for a number of systems.
</p>
</dd>
-<dt><span><code>--with-curses</code></span></dt>
+<dt><code class="code">--with-curses</code></dt>
<dd><p>Use the curses library instead of the termcap library. This should
be supplied if your system has an inadequate or incomplete termcap
database.
</p>
</dd>
-<dt><span><code>--with-gnu-malloc</code></span></dt>
-<dd><p>A synonym for <code>--with-bash-malloc</code>.
+<dt><code class="code">--with-gnu-malloc</code></dt>
+<dd><p>A synonym for <code class="code">--with-bash-malloc</code>.
</p>
</dd>
-<dt><span><code>--with-installed-readline[=<var>PREFIX</var>]</code></span></dt>
+<dt><code class="code">--with-installed-readline[=<var class="var">PREFIX</var>]</code></dt>
<dd><p>Define this to make Bash link with a locally-installed version of Readline
-rather than the version in <samp>lib/readline</samp>. This works only with
-Readline 5.0 and later versions. If <var>PREFIX</var> is <code>yes</code> or not
-supplied, <code>configure</code> uses the values of the make variables
-<code>includedir</code> and <code>libdir</code>, which are subdirectories of <code>prefix</code>
+rather than the version in <samp class="file">lib/readline</samp>. This works only with
+Readline 5.0 and later versions. If <var class="var">PREFIX</var> is <code class="code">yes</code> or not
+supplied, <code class="code">configure</code> uses the values of the make variables
+<code class="code">includedir</code> and <code class="code">libdir</code>, which are subdirectories of <code class="code">prefix</code>
by default, to find the installed version of Readline if it is not in
the standard system include and library directories.
-If <var>PREFIX</var> is <code>no</code>, Bash links with the version in
-<samp>lib/readline</samp>.
-If <var>PREFIX</var> is set to any other value, <code>configure</code> treats it as
+If <var class="var">PREFIX</var> is <code class="code">no</code>, Bash links with the version in
+<samp class="file">lib/readline</samp>.
+If <var class="var">PREFIX</var> is set to any other value, <code class="code">configure</code> treats it as
a directory pathname and looks for
the installed version of Readline in subdirectories of that directory
-(include files in <var>PREFIX</var>/<code>include</code> and the library in
-<var>PREFIX</var>/<code>lib</code>).
+(include files in <var class="var">PREFIX</var>/<code class="code">include</code> and the library in
+<var class="var">PREFIX</var>/<code class="code">lib</code>).
</p>
</dd>
-<dt><span><code>--with-libintl-prefix[=<var>PREFIX</var>]</code></span></dt>
+<dt><code class="code">--with-libintl-prefix[=<var class="var">PREFIX</var>]</code></dt>
<dd><p>Define this to make Bash link with a locally-installed version of the
-libintl library instead of the version in <samp>lib/intl</samp>.
+libintl library instead of the version in <samp class="file">lib/intl</samp>.
</p>
</dd>
-<dt><span><code>--with-libiconv-prefix[=<var>PREFIX</var>]</code></span></dt>
-<dd><p>Define this to make Bash look for libiconv in <var>PREFIX</var> instead of the
+<dt><code class="code">--with-libiconv-prefix[=<var class="var">PREFIX</var>]</code></dt>
+<dd><p>Define this to make Bash look for libiconv in <var class="var">PREFIX</var> instead of the
standard system locations. There is no version included with Bash.
</p>
</dd>
-<dt><span><code>--enable-minimal-config</code></span></dt>
+<dt><code class="code">--enable-minimal-config</code></dt>
<dd><p>This produces a shell with minimal features, close to the historical
Bourne shell.
</p></dd>
</dl>
-<p>There are several <samp>--enable-</samp> options that alter how Bash is
+<p>There are several <samp class="option">--enable-</samp> options that alter how Bash is
compiled, linked, and installed, rather than changing run-time features.
</p>
-<dl compact="compact">
-<dt><span><code>--enable-largefile</code></span></dt>
-<dd><p>Enable support for <a href="http://www.unix.org/version2/whatsnew/lfs20mar.html">large files</a> if the operating system requires special compiler options
+<dl class="table">
+<dt><code class="code">--enable-largefile</code></dt>
+<dd><p>Enable support for <a class="url" href="http://www.unix.org/version2/whatsnew/lfs20mar.html">large files</a> if the operating system requires special compiler options
to build programs which can access large files. This is enabled by
default, if the operating system provides large file support.
</p>
</dd>
-<dt><span><code>--enable-profiling</code></span></dt>
+<dt><code class="code">--enable-profiling</code></dt>
<dd><p>This builds a Bash binary that produces profiling information to be
-processed by <code>gprof</code> each time it is executed.
+processed by <code class="code">gprof</code> each time it is executed.
</p>
</dd>
-<dt><span><code>--enable-separate-helpfiles</code></span></dt>
-<dd><p>Use external files for the documentation displayed by the <code>help</code> builtin
+<dt><code class="code">--enable-separate-helpfiles</code></dt>
+<dd><p>Use external files for the documentation displayed by the <code class="code">help</code> builtin
instead of storing the text internally.
</p>
</dd>
-<dt><span><code>--enable-static-link</code></span></dt>
-<dd><p>This causes Bash to be linked statically, if <code>gcc</code> is being used.
+<dt><code class="code">--enable-static-link</code></dt>
+<dd><p>This causes Bash to be linked statically, if <code class="code">gcc</code> is being used.
This could be used to build a version to use as root’s shell.
</p>
</dd>
</dl>
-<p>The ‘<samp>minimal-config</samp>’ option can be used to disable all of
+<p>The ‘<samp class="samp">minimal-config</samp>’ option can be used to disable all of
the following options, but it is processed first, so individual
-options may be enabled using ‘<samp>enable-<var>feature</var></samp>’.
+options may be enabled using ‘<samp class="samp">enable-<var class="var">feature</var></samp>’.
</p>
<p>All of the following options except for
-‘<samp>alt-array-implementation</samp>’,
-‘<samp>disabled-builtins</samp>’,
-‘<samp>direxpand-default</samp>’,
-‘<samp>strict-posix-default</samp>’,
+‘<samp class="samp">alt-array-implementation</samp>’,
+‘<samp class="samp">disabled-builtins</samp>’,
+‘<samp class="samp">direxpand-default</samp>’,
+‘<samp class="samp">strict-posix-default</samp>’,
and
-‘<samp>xpg-echo-default</samp>’ are
+‘<samp class="samp">xpg-echo-default</samp>’ are
enabled by default, unless the operating system does not provide the
necessary support.
</p>
-<dl compact="compact">
-<dt><span><code>--enable-alias</code></span></dt>
-<dd><p>Allow alias expansion and include the <code>alias</code> and <code>unalias</code>
-builtins (see <a href="#Aliases">Aliases</a>).
+<dl class="table">
+<dt><code class="code">--enable-alias</code></dt>
+<dd><p>Allow alias expansion and include the <code class="code">alias</code> and <code class="code">unalias</code>
+builtins (see <a class="pxref" href="#Aliases">Aliases</a>).
</p>
</dd>
-<dt><span><code>--enable-alt-array-implementation</code></span></dt>
+<dt><code class="code">--enable-alt-array-implementation</code></dt>
<dd><p>This builds Bash using an alternate implementation of arrays
-(see <a href="#Arrays">Arrays</a>) that provides faster access at the expense of using
+(see <a class="pxref" href="#Arrays">Arrays</a>) that provides faster access at the expense of using
more memory (sometimes many times more, depending on how sparse an array is).
</p>
</dd>
-<dt><span><code>--enable-arith-for-command</code></span></dt>
-<dd><p>Include support for the alternate form of the <code>for</code> command
-that behaves like the C language <code>for</code> statement
-(see <a href="#Looping-Constructs">Looping Constructs</a>).
+<dt><code class="code">--enable-arith-for-command</code></dt>
+<dd><p>Include support for the alternate form of the <code class="code">for</code> command
+that behaves like the C language <code class="code">for</code> statement
+(see <a class="pxref" href="#Looping-Constructs">Looping Constructs</a>).
</p>
</dd>
-<dt><span><code>--enable-array-variables</code></span></dt>
+<dt><code class="code">--enable-array-variables</code></dt>
<dd><p>Include support for one-dimensional array shell variables
-(see <a href="#Arrays">Arrays</a>).
+(see <a class="pxref" href="#Arrays">Arrays</a>).
</p>
</dd>
-<dt><span><code>--enable-bang-history</code></span></dt>
-<dd><p>Include support for <code>csh</code>-like history substitution
-(see <a href="#History-Interaction">History Expansion</a>).
+<dt><code class="code">--enable-bang-history</code></dt>
+<dd><p>Include support for <code class="code">csh</code>-like history substitution
+(see <a class="pxref" href="#History-Interaction">History Expansion</a>).
</p>
</dd>
-<dt><span><code>--enable-brace-expansion</code></span></dt>
-<dd><p>Include <code>csh</code>-like brace expansion
-( <code>b{a,b}c</code> → <code>bac bbc</code> ).
-See <a href="#Brace-Expansion">Brace Expansion</a>, for a complete description.
+<dt><code class="code">--enable-brace-expansion</code></dt>
+<dd><p>Include <code class="code">csh</code>-like brace expansion
+( <code class="code">b{a,b}c</code> → <code class="code">bac bbc</code> ).
+See <a class="ref" href="#Brace-Expansion">Brace Expansion</a>, for a complete description.
</p>
</dd>
-<dt><span><code>--enable-casemod-attributes</code></span></dt>
-<dd><p>Include support for case-modifying attributes in the <code>declare</code> builtin
-and assignment statements. Variables with the <code>uppercase</code> attribute,
+<dt><code class="code">--enable-casemod-attributes</code></dt>
+<dd><p>Include support for case-modifying attributes in the <code class="code">declare</code> builtin
+and assignment statements. Variables with the <code class="code">uppercase</code> attribute,
for example, will have their values converted to uppercase upon assignment.
</p>
</dd>
-<dt><span><code>--enable-casemod-expansion</code></span></dt>
+<dt><code class="code">--enable-casemod-expansion</code></dt>
<dd><p>Include support for case-modifying word expansions.
</p>
</dd>
-<dt><span><code>--enable-command-timing</code></span></dt>
-<dd><p>Include support for recognizing <code>time</code> as a reserved word and for
-displaying timing statistics for the pipeline following <code>time</code>
-(see <a href="#Pipelines">Pipelines</a>).
+<dt><code class="code">--enable-command-timing</code></dt>
+<dd><p>Include support for recognizing <code class="code">time</code> as a reserved word and for
+displaying timing statistics for the pipeline following <code class="code">time</code>
+(see <a class="pxref" href="#Pipelines">Pipelines</a>).
This allows pipelines as well as shell builtins and functions to be timed.
</p>
</dd>
-<dt><span><code>--enable-cond-command</code></span></dt>
-<dd><p>Include support for the <code>[[</code> conditional command.
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+<dt><code class="code">--enable-cond-command</code></dt>
+<dd><p>Include support for the <code class="code">[[</code> conditional command.
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
</p>
</dd>
-<dt><span><code>--enable-cond-regexp</code></span></dt>
-<dd><p>Include support for matching <small>POSIX</small> regular expressions using the
-‘<samp>=~</samp>’ binary operator in the <code>[[</code> conditional command.
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+<dt><code class="code">--enable-cond-regexp</code></dt>
+<dd><p>Include support for matching <small class="sc">POSIX</small> regular expressions using the
+‘<samp class="samp">=~</samp>’ binary operator in the <code class="code">[[</code> conditional command.
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
</p>
</dd>
-<dt><span><code>--enable-coprocesses</code></span></dt>
-<dd><p>Include support for coprocesses and the <code>coproc</code> reserved word
-(see <a href="#Pipelines">Pipelines</a>).
+<dt><code class="code">--enable-coprocesses</code></dt>
+<dd><p>Include support for coprocesses and the <code class="code">coproc</code> reserved word
+(see <a class="pxref" href="#Pipelines">Pipelines</a>).
</p>
</dd>
-<dt><span><code>--enable-debugger</code></span></dt>
+<dt><code class="code">--enable-debugger</code></dt>
<dd><p>Include support for the Bash debugger (distributed separately).
</p>
</dd>
-<dt><span><code>--enable-dev-fd-stat-broken</code></span></dt>
-<dd><p>If calling <code>stat</code> on /dev/fd/<var>N</var> returns different results than
-calling <code>fstat</code> on file descriptor <var>N</var>, supply this option to
+<dt><code class="code">--enable-dev-fd-stat-broken</code></dt>
+<dd><p>If calling <code class="code">stat</code> on /dev/fd/<var class="var">N</var> returns different results than
+calling <code class="code">fstat</code> on file descriptor <var class="var">N</var>, supply this option to
enable a workaround.
This has implications for conditional commands that test file attributes.
</p>
</dd>
-<dt><span><code>--enable-direxpand-default</code></span></dt>
-<dd><p>Cause the <code>direxpand</code> shell option (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>)
+<dt><code class="code">--enable-direxpand-default</code></dt>
+<dd><p>Cause the <code class="code">direxpand</code> shell option (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>)
to be enabled by default when the shell starts.
It is normally disabled by default.
</p>
</dd>
-<dt><span><code>--enable-directory-stack</code></span></dt>
-<dd><p>Include support for a <code>csh</code>-like directory stack and the
-<code>pushd</code>, <code>popd</code>, and <code>dirs</code> builtins
-(see <a href="#The-Directory-Stack">The Directory Stack</a>).
+<dt><code class="code">--enable-directory-stack</code></dt>
+<dd><p>Include support for a <code class="code">csh</code>-like directory stack and the
+<code class="code">pushd</code>, <code class="code">popd</code>, and <code class="code">dirs</code> builtins
+(see <a class="pxref" href="#The-Directory-Stack">The Directory Stack</a>).
</p>
</dd>
-<dt><span><code>--enable-disabled-builtins</code></span></dt>
-<dd><p>Allow builtin commands to be invoked via ‘<samp>builtin xxx</samp>’
-even after <code>xxx</code> has been disabled using ‘<samp>enable -n xxx</samp>’.
-See <a href="#Bash-Builtins">Bash Builtin Commands</a>, for details of the <code>builtin</code> and
-<code>enable</code> builtin commands.
+<dt><code class="code">--enable-disabled-builtins</code></dt>
+<dd><p>Allow builtin commands to be invoked via ‘<samp class="samp">builtin xxx</samp>’
+even after <code class="code">xxx</code> has been disabled using ‘<samp class="samp">enable -n xxx</samp>’.
+See <a class="ref" href="#Bash-Builtins">Bash Builtin Commands</a>, for details of the <code class="code">builtin</code> and
+<code class="code">enable</code> builtin commands.
</p>
</dd>
-<dt><span><code>--enable-dparen-arithmetic</code></span></dt>
-<dd><p>Include support for the <code>((…))</code> command
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+<dt><code class="code">--enable-dparen-arithmetic</code></dt>
+<dd><p>Include support for the <code class="code">((…))</code> command
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
</p>
</dd>
-<dt><span><code>--enable-extended-glob</code></span></dt>
+<dt><code class="code">--enable-extended-glob</code></dt>
<dd><p>Include support for the extended pattern matching features described
-above under <a href="#Pattern-Matching">Pattern Matching</a>.
+above under <a class="ref" href="#Pattern-Matching">Pattern Matching</a>.
</p>
</dd>
-<dt><span><code>--enable-extended-glob-default</code></span></dt>
-<dd><p>Set the default value of the <code>extglob</code> shell option described
-above under <a href="#The-Shopt-Builtin">The Shopt Builtin</a> to be enabled.
+<dt><code class="code">--enable-extended-glob-default</code></dt>
+<dd><p>Set the default value of the <code class="code">extglob</code> shell option described
+above under <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a> to be enabled.
</p>
</dd>
-<dt><span><code>--enable-function-import</code></span></dt>
+<dt><code class="code">--enable-function-import</code></dt>
<dd><p>Include support for importing function definitions exported by another
instance of the shell from the environment. This option is enabled by
default.
</p>
</dd>
-<dt><span><code>--enable-glob-asciiranges-default</code></span></dt>
-<dd><p>Set the default value of the <code>globasciiranges</code> shell option described
-above under <a href="#The-Shopt-Builtin">The Shopt Builtin</a> to be enabled.
+<dt><code class="code">--enable-glob-asciiranges-default</code></dt>
+<dd><p>Set the default value of the <code class="code">globasciiranges</code> shell option described
+above under <a class="ref" href="#The-Shopt-Builtin">The Shopt Builtin</a> to be enabled.
This controls the behavior of character ranges when used in pattern matching
bracket expressions.
</p>
</dd>
-<dt><span><code>--enable-help-builtin</code></span></dt>
-<dd><p>Include the <code>help</code> builtin, which displays help on shell builtins and
-variables (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+<dt><code class="code">--enable-help-builtin</code></dt>
+<dd><p>Include the <code class="code">help</code> builtin, which displays help on shell builtins and
+variables (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
</p>
</dd>
-<dt><span><code>--enable-history</code></span></dt>
-<dd><p>Include command history and the <code>fc</code> and <code>history</code>
-builtin commands (see <a href="#Bash-History-Facilities">Bash History Facilities</a>).
+<dt><code class="code">--enable-history</code></dt>
+<dd><p>Include command history and the <code class="code">fc</code> and <code class="code">history</code>
+builtin commands (see <a class="pxref" href="#Bash-History-Facilities">Bash History Facilities</a>).
</p>
</dd>
-<dt><span><code>--enable-job-control</code></span></dt>
-<dd><p>This enables the job control features (see <a href="#Job-Control">Job Control</a>),
+<dt><code class="code">--enable-job-control</code></dt>
+<dd><p>This enables the job control features (see <a class="pxref" href="#Job-Control">Job Control</a>),
if the operating system supports them.
</p>
</dd>
-<dt><span><code>--enable-multibyte</code></span></dt>
+<dt><code class="code">--enable-multibyte</code></dt>
<dd><p>This enables support for multibyte characters if the operating
system provides the necessary support.
</p>
</dd>
-<dt><span><code>--enable-net-redirections</code></span></dt>
+<dt><code class="code">--enable-net-redirections</code></dt>
<dd><p>This enables the special handling of filenames of the form
-<code>/dev/tcp/<var>host</var>/<var>port</var></code> and
-<code>/dev/udp/<var>host</var>/<var>port</var></code>
-when used in redirections (see <a href="#Redirections">Redirections</a>).
+<code class="code">/dev/tcp/<var class="var">host</var>/<var class="var">port</var></code> and
+<code class="code">/dev/udp/<var class="var">host</var>/<var class="var">port</var></code>
+when used in redirections (see <a class="pxref" href="#Redirections">Redirections</a>).
</p>
</dd>
-<dt><span><code>--enable-process-substitution</code></span></dt>
-<dd><p>This enables process substitution (see <a href="#Process-Substitution">Process Substitution</a>) if
+<dt><code class="code">--enable-process-substitution</code></dt>
+<dd><p>This enables process substitution (see <a class="pxref" href="#Process-Substitution">Process Substitution</a>) if
the operating system provides the necessary support.
</p>
</dd>
-<dt><span><code>--enable-progcomp</code></span></dt>
+<dt><code class="code">--enable-progcomp</code></dt>
<dd><p>Enable the programmable completion facilities
-(see <a href="#Programmable-Completion">Programmable Completion</a>).
+(see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>).
If Readline is not enabled, this option has no effect.
</p>
</dd>
-<dt><span><code>--enable-prompt-string-decoding</code></span></dt>
+<dt><code class="code">--enable-prompt-string-decoding</code></dt>
<dd><p>Turn on the interpretation of a number of backslash-escaped characters
-in the <code>$PS0</code>, <code>$PS1</code>, <code>$PS2</code>, and <code>$PS4</code> prompt
-strings. See <a href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt
+in the <code class="env">$PS0</code>, <code class="env">$PS1</code>, <code class="env">$PS2</code>, and <code class="env">$PS4</code> prompt
+strings. See <a class="ref" href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt
string escape sequences.
</p>
</dd>
-<dt><span><code>--enable-readline</code></span></dt>
+<dt><code class="code">--enable-readline</code></dt>
<dd><p>Include support for command-line editing and history with the Bash
-version of the Readline library (see <a href="#Command-Line-Editing">Command Line Editing</a>).
+version of the Readline library (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>).
</p>
</dd>
-<dt><span><code>--enable-restricted</code></span></dt>
-<dd><p>Include support for a <em>restricted shell</em>. If this is enabled, Bash,
-when called as <code>rbash</code>, enters a restricted mode. See
-<a href="#The-Restricted-Shell">The Restricted Shell</a>, for a description of restricted mode.
+<dt><code class="code">--enable-restricted</code></dt>
+<dd><p>Include support for a <em class="dfn">restricted shell</em>. If this is enabled, Bash,
+when called as <code class="code">rbash</code>, enters a restricted mode. See
+<a class="ref" href="#The-Restricted-Shell">The Restricted Shell</a>, for a description of restricted mode.
</p>
</dd>
-<dt><span><code>--enable-select</code></span></dt>
-<dd><p>Include the <code>select</code> compound command, which allows the generation of
-simple menus (see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+<dt><code class="code">--enable-select</code></dt>
+<dd><p>Include the <code class="code">select</code> compound command, which allows the generation of
+simple menus (see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
</p>
</dd>
-<dt><span><code>--enable-single-help-strings</code></span></dt>
-<dd><p>Store the text displayed by the <code>help</code> builtin as a single string for
+<dt><code class="code">--enable-single-help-strings</code></dt>
+<dd><p>Store the text displayed by the <code class="code">help</code> builtin as a single string for
each help topic. This aids in translating the text to different languages.
You may need to disable this if your compiler cannot handle very long string
literals.
</p>
</dd>
-<dt><span><code>--enable-strict-posix-default</code></span></dt>
-<dd><p>Make Bash <small>POSIX</small>-conformant by default (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>).
+<dt><code class="code">--enable-strict-posix-default</code></dt>
+<dd><p>Make Bash <small class="sc">POSIX</small>-conformant by default (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>).
</p>
</dd>
-<dt><span><code>--enable-translatable-strings</code></span></dt>
-<dd><p>Enable support for <code>$"<var>string</var>"</code> translatable strings
-(see <a href="#Locale-Translation">Locale-Specific Translation</a>).
+<dt><code class="code">--enable-translatable-strings</code></dt>
+<dd><p>Enable support for <code class="code">$"<var class="var">string</var>"</code> translatable strings
+(see <a class="pxref" href="#Locale-Translation">Locale-Specific Translation</a>).
</p>
</dd>
-<dt><span><code>--enable-usg-echo-default</code></span></dt>
-<dd><p>A synonym for <code>--enable-xpg-echo-default</code>.
+<dt><code class="code">--enable-usg-echo-default</code></dt>
+<dd><p>A synonym for <code class="code">--enable-xpg-echo-default</code>.
</p>
</dd>
-<dt><span><code>--enable-xpg-echo-default</code></span></dt>
-<dd><p>Make the <code>echo</code> builtin expand backslash-escaped characters by default,
-without requiring the <samp>-e</samp> option.
-This sets the default value of the <code>xpg_echo</code> shell option to <code>on</code>,
-which makes the Bash <code>echo</code> behave more like the version specified in
+<dt><code class="code">--enable-xpg-echo-default</code></dt>
+<dd><p>Make the <code class="code">echo</code> builtin expand backslash-escaped characters by default,
+without requiring the <samp class="option">-e</samp> option.
+This sets the default value of the <code class="code">xpg_echo</code> shell option to <code class="code">on</code>,
+which makes the Bash <code class="code">echo</code> behave more like the version specified in
the Single Unix Specification, version 3.
-See <a href="#Bash-Builtins">Bash Builtin Commands</a>, for a description of the escape sequences that
-<code>echo</code> recognizes.
+See <a class="xref" href="#Bash-Builtins">Bash Builtin Commands</a>, for a description of the escape sequences that
+<code class="code">echo</code> recognizes.
</p></dd>
</dl>
-<p>The file <samp>config-top.h</samp> contains C Preprocessor
-‘<samp>#define</samp>’ statements for options which are not settable from
-<code>configure</code>.
+<p>The file <samp class="file">config-top.h</samp> contains C Preprocessor
+‘<samp class="samp">#define</samp>’ statements for options which are not settable from
+<code class="code">configure</code>.
Some of these are not meant to be changed; beware of the consequences if
you do.
Read the comments associated with each definition for more
<hr>
</div>
</div>
-<div class="appendix" id="Reporting-Bugs">
-<div class="header">
+<div class="appendix-level-extent" id="Reporting-Bugs">
+<div class="nav-panel">
<p>
Next: <a href="#Major-Differences-From-The-Bourne-Shell" accesskey="n" rel="next">Major Differences From The Bourne Shell</a>, Previous: <a href="#Installing-Bash" accesskey="p" rel="prev">Installing Bash</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Reporting-Bugs-1"></span><h2 class="appendix">Appendix A Reporting Bugs</h2>
+<h2 class="appendix" id="Reporting-Bugs-1"><span>Appendix A Reporting Bugs<a class="copiable-link" href="#Reporting-Bugs-1"> ¶</a></span></h2>
<p>Please report all bugs you find in Bash.
But first, you should
make sure that it really is a bug, and that it appears in the latest
version of Bash.
The latest version of Bash is always available for FTP from
-<a href="ftp://ftp.gnu.org/pub/gnu/bash/">ftp://ftp.gnu.org/pub/gnu/bash/</a> and from
-<a href="http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-master.tar.gz">http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-master.tar.gz</a>.
+<a class="uref" href="ftp://ftp.gnu.org/pub/gnu/bash/">ftp://ftp.gnu.org/pub/gnu/bash/</a> and from
+<a class="uref" href="http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-master.tar.gz">http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-master.tar.gz</a>.
</p>
<p>Once you have determined that a bug actually exists, use the
-<code>bashbug</code> command to submit a bug report or use the form at the
-<a href="https://savannah.gnu.org/projects/bash/">Bash project page</a>.
+<code class="code">bashbug</code> command to submit a bug report or use the form at the
+<a class="uref" href="https://savannah.gnu.org/projects/bash/">Bash project page</a>.
If you have a fix, you are encouraged to submit that as well!
Suggestions and ‘philosophical’ bug reports may be mailed
-to <a href="mailto:bug-bash@gnu.org">bug-bash@gnu.org</a> or <a href="mailto:help-bash@gnu.org">help-bash@gnu.org</a>.
+to <a class="email" href="mailto:bug-bash@gnu.org">bug-bash@gnu.org</a> or <a class="email" href="mailto:help-bash@gnu.org">help-bash@gnu.org</a>.
</p>
<p>All bug reports should include:
-</p><ul>
-<li> The version number of Bash.
-</li><li> The hardware and operating system.
-</li><li> The compiler used to compile Bash.
-</li><li> A description of the bug behaviour.
-</li><li> A short script or ‘recipe’ which exercises the bug and may be used
+</p><ul class="itemize mark-bullet">
+<li>The version number of Bash.
+</li><li>The hardware and operating system.
+</li><li>The compiler used to compile Bash.
+</li><li>A description of the bug behaviour.
+</li><li>A short script or ‘recipe’ which exercises the bug and may be used
to reproduce it.
</li></ul>
-<p><code>bashbug</code> inserts the first three items automatically into
+<p><code class="code">bashbug</code> inserts the first three items automatically into
the template it provides for filing a bug report.
</p>
<p>Please send all reports concerning this manual to
-<a href="mailto:bug-bash@gnu.org">bug-bash@gnu.org</a>.
+<a class="email" href="mailto:bug-bash@gnu.org">bug-bash@gnu.org</a>.
</p>
<hr>
</div>
-<div class="appendix" id="Major-Differences-From-The-Bourne-Shell">
-<div class="header">
+<div class="appendix-level-extent" id="Major-Differences-From-The-Bourne-Shell">
+<div class="nav-panel">
<p>
Next: <a href="#GNU-Free-Documentation-License" accesskey="n" rel="next">GNU Free Documentation License</a>, Previous: <a href="#Reporting-Bugs" accesskey="p" rel="prev">Reporting Bugs</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Major-Differences-From-The-Bourne-Shell-1"></span><h2 class="appendix">Appendix B Major Differences From The Bourne Shell</h2>
+<h2 class="appendix" id="Major-Differences-From-The-Bourne-Shell-1"><span>Appendix B Major Differences From The Bourne Shell<a class="copiable-link" href="#Major-Differences-From-The-Bourne-Shell-1"> ¶</a></span></h2>
<p>Bash implements essentially the same grammar, parameter and
variable expansion, redirection, and quoting as the Bourne Shell.
-Bash uses the <small>POSIX</small> standard as the specification of
+Bash uses the <small class="sc">POSIX</small> standard as the specification of
how these features are to be implemented. There are some
differences between the traditional Bourne shell and Bash; this
section quickly details the differences of significance. A
number of these differences are explained in greater depth in
previous sections.
-This section uses the version of <code>sh</code> included in SVR4.2 (the
+This section uses the version of <code class="code">sh</code> included in SVR4.2 (the
last version of the historical Bourne shell) as the baseline reference.
</p>
-<ul>
-<li> Bash is <small>POSIX</small>-conformant, even where the <small>POSIX</small> specification
-differs from traditional <code>sh</code> behavior (see <a href="#Bash-POSIX-Mode">Bash and POSIX</a>).
+<ul class="itemize mark-bullet">
+<li>Bash is <small class="sc">POSIX</small>-conformant, even where the <small class="sc">POSIX</small> specification
+differs from traditional <code class="code">sh</code> behavior (see <a class="pxref" href="#Bash-POSIX-Mode">Bash and POSIX</a>).
-</li><li> Bash has multi-character invocation options (see <a href="#Invoking-Bash">Invoking Bash</a>).
+</li><li>Bash has multi-character invocation options (see <a class="pxref" href="#Invoking-Bash">Invoking Bash</a>).
-</li><li> Bash has command-line editing (see <a href="#Command-Line-Editing">Command Line Editing</a>) and
-the <code>bind</code> builtin.
+</li><li>Bash has command-line editing (see <a class="pxref" href="#Command-Line-Editing">Command Line Editing</a>) and
+the <code class="code">bind</code> builtin.
-</li><li> Bash provides a programmable word completion mechanism
-(see <a href="#Programmable-Completion">Programmable Completion</a>), and builtin commands
-<code>complete</code>, <code>compgen</code>, and <code>compopt</code>, to
+</li><li>Bash provides a programmable word completion mechanism
+(see <a class="pxref" href="#Programmable-Completion">Programmable Completion</a>), and builtin commands
+<code class="code">complete</code>, <code class="code">compgen</code>, and <code class="code">compopt</code>, to
manipulate it.
-</li><li> Bash has command history (see <a href="#Bash-History-Facilities">Bash History Facilities</a>) and the
-<code>history</code> and <code>fc</code> builtins to manipulate it.
+</li><li>Bash has command history (see <a class="pxref" href="#Bash-History-Facilities">Bash History Facilities</a>) and the
+<code class="code">history</code> and <code class="code">fc</code> builtins to manipulate it.
The Bash history list maintains timestamp information and uses the
-value of the <code>HISTTIMEFORMAT</code> variable to display it.
+value of the <code class="code">HISTTIMEFORMAT</code> variable to display it.
-</li><li> Bash implements <code>csh</code>-like history expansion
-(see <a href="#History-Interaction">History Expansion</a>).
+</li><li>Bash implements <code class="code">csh</code>-like history expansion
+(see <a class="pxref" href="#History-Interaction">History Expansion</a>).
-</li><li> Bash has one-dimensional array variables (see <a href="#Arrays">Arrays</a>), and the
+</li><li>Bash has one-dimensional array variables (see <a class="pxref" href="#Arrays">Arrays</a>), and the
appropriate variable expansions and assignment syntax to use them.
Several of the Bash builtins take options to act on arrays.
Bash provides a number of built-in array variables.
-</li><li> The <code>$'…'</code> quoting syntax, which expands ANSI-C
+</li><li>The <code class="code">$'…'</code> quoting syntax, which expands ANSI-C
backslash-escaped characters in the text between the single quotes,
-is supported (see <a href="#ANSI_002dC-Quoting">ANSI-C Quoting</a>).
+is supported (see <a class="pxref" href="#ANSI_002dC-Quoting">ANSI-C Quoting</a>).
-</li><li> Bash supports the <code>$"…"</code> quoting syntax to do
+</li><li>Bash supports the <code class="code">$"…"</code> quoting syntax to do
locale-specific translation of the characters between the double
-quotes. The <samp>-D</samp>, <samp>--dump-strings</samp>, and <samp>--dump-po-strings</samp>
+quotes. The <samp class="option">-D</samp>, <samp class="option">--dump-strings</samp>, and <samp class="option">--dump-po-strings</samp>
invocation options list the translatable strings found in a script
-(see <a href="#Locale-Translation">Locale-Specific Translation</a>).
+(see <a class="pxref" href="#Locale-Translation">Locale-Specific Translation</a>).
-</li><li> Bash implements the <code>!</code> keyword to negate the return value of
-a pipeline (see <a href="#Pipelines">Pipelines</a>).
-Very useful when an <code>if</code> statement needs to act only if a test fails.
-The Bash ‘<samp>-o pipefail</samp>’ option to <code>set</code> will cause a pipeline to
+</li><li>Bash implements the <code class="code">!</code> keyword to negate the return value of
+a pipeline (see <a class="pxref" href="#Pipelines">Pipelines</a>).
+Very useful when an <code class="code">if</code> statement needs to act only if a test fails.
+The Bash ‘<samp class="samp">-o pipefail</samp>’ option to <code class="code">set</code> will cause a pipeline to
return a failure status if any command fails.
-</li><li> Bash has the <code>time</code> reserved word and command timing (see <a href="#Pipelines">Pipelines</a>).
+</li><li>Bash has the <code class="code">time</code> reserved word and command timing (see <a class="pxref" href="#Pipelines">Pipelines</a>).
The display of the timing statistics may be controlled with the
-<code>TIMEFORMAT</code> variable.
+<code class="env">TIMEFORMAT</code> variable.
-</li><li> Bash implements the <code>for (( <var>expr1</var> ; <var>expr2</var> ; <var>expr3</var> ))</code>
-arithmetic for command, similar to the C language (see <a href="#Looping-Constructs">Looping Constructs</a>).
+</li><li>Bash implements the <code class="code">for (( <var class="var">expr1</var> ; <var class="var">expr2</var> ; <var class="var">expr3</var> ))</code>
+arithmetic for command, similar to the C language (see <a class="pxref" href="#Looping-Constructs">Looping Constructs</a>).
-</li><li> Bash includes the <code>select</code> compound command, which allows the
-generation of simple menus (see <a href="#Conditional-Constructs">Conditional Constructs</a>).
+</li><li>Bash includes the <code class="code">select</code> compound command, which allows the
+generation of simple menus (see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>).
-</li><li> Bash includes the <code>[[</code> compound command, which makes conditional
-testing part of the shell grammar (see <a href="#Conditional-Constructs">Conditional Constructs</a>), including
+</li><li>Bash includes the <code class="code">[[</code> compound command, which makes conditional
+testing part of the shell grammar (see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>), including
optional regular expression matching.
-</li><li> Bash provides optional case-insensitive matching for the <code>case</code> and
-<code>[[</code> constructs.
+</li><li>Bash provides optional case-insensitive matching for the <code class="code">case</code> and
+<code class="code">[[</code> constructs.
-</li><li> Bash includes brace expansion (see <a href="#Brace-Expansion">Brace Expansion</a>) and tilde
-expansion (see <a href="#Tilde-Expansion">Tilde Expansion</a>).
+</li><li>Bash includes brace expansion (see <a class="pxref" href="#Brace-Expansion">Brace Expansion</a>) and tilde
+expansion (see <a class="pxref" href="#Tilde-Expansion">Tilde Expansion</a>).
-</li><li> Bash implements command aliases and the <code>alias</code> and <code>unalias</code>
-builtins (see <a href="#Aliases">Aliases</a>).
+</li><li>Bash implements command aliases and the <code class="code">alias</code> and <code class="code">unalias</code>
+builtins (see <a class="pxref" href="#Aliases">Aliases</a>).
-</li><li> Bash provides shell arithmetic, the <code>((</code> compound command
-(see <a href="#Conditional-Constructs">Conditional Constructs</a>),
-and arithmetic expansion (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>).
+</li><li>Bash provides shell arithmetic, the <code class="code">((</code> compound command
+(see <a class="pxref" href="#Conditional-Constructs">Conditional Constructs</a>),
+and arithmetic expansion (see <a class="pxref" href="#Shell-Arithmetic">Shell Arithmetic</a>).
-</li><li> Variables present in the shell’s initial environment are automatically
+</li><li>Variables present in the shell’s initial environment are automatically
exported to child processes. The Bourne shell does not normally do
-this unless the variables are explicitly marked using the <code>export</code>
+this unless the variables are explicitly marked using the <code class="code">export</code>
command.
-</li><li> Bash supports the ‘<samp>+=</samp>’ assignment operator, which appends to the value
+</li><li>Bash supports the ‘<samp class="samp">+=</samp>’ assignment operator, which appends to the value
of the variable named on the left hand side.
-</li><li> Bash includes the <small>POSIX</small> pattern removal ‘<samp>%</samp>’, ‘<samp>#</samp>’, ‘<samp>%%</samp>’
-and ‘<samp>##</samp>’ expansions to remove leading or trailing substrings from
-variable values (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li>Bash includes the <small class="sc">POSIX</small> pattern removal ‘<samp class="samp">%</samp>’, ‘<samp class="samp">#</samp>’, ‘<samp class="samp">%%</samp>’
+and ‘<samp class="samp">##</samp>’ expansions to remove leading or trailing substrings from
+variable values (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-</li><li> The expansion <code>${#xx}</code>, which returns the length of <code>${xx}</code>,
-is supported (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li>The expansion <code class="code">${#xx}</code>, which returns the length of <code class="code">${xx}</code>,
+is supported (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-</li><li> The expansion <code>${var:</code><var>offset</var><code>[:</code><var>length</var><code>]}</code>,
-which expands to the substring of <code>var</code>’s value of length
-<var>length</var>, beginning at <var>offset</var>, is present
-(see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li>The expansion <code class="code">${var:</code><var class="var">offset</var><code class="code">[:</code><var class="var">length</var><code class="code">]}</code>,
+which expands to the substring of <code class="code">var</code>’s value of length
+<var class="var">length</var>, beginning at <var class="var">offset</var>, is present
+(see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-</li><li> The expansion
-<code>${<var>var</var>/[/]</code><var>pattern</var><code>[/</code><var>replacement</var><code>]}</code>,
-which matches <var>pattern</var> and replaces it with <var>replacement</var> in
-the value of <var>var</var>, is available (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li>The expansion
+<code class="code">${<var class="var">var</var>/[/]</code><var class="var">pattern</var><code class="code">[/</code><var class="var">replacement</var><code class="code">]}</code>,
+which matches <var class="var">pattern</var> and replaces it with <var class="var">replacement</var> in
+the value of <var class="var">var</var>, is available (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-</li><li> The expansion <code>${!<var>prefix</var>*}</code> expansion, which expands to
-the names of all shell variables whose names begin with <var>prefix</var>,
-is available (see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li>The expansion <code class="code">${!<var class="var">prefix</var>*}</code> expansion, which expands to
+the names of all shell variables whose names begin with <var class="var">prefix</var>,
+is available (see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-</li><li> Bash has indirect variable expansion using <code>${!word}</code>
-(see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
+</li><li>Bash has indirect variable expansion using <code class="code">${!word}</code>
+(see <a class="pxref" href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>).
-</li><li> Bash can expand positional parameters beyond <code>$9</code> using
-<code>${<var>num</var>}</code>.
+</li><li>Bash can expand positional parameters beyond <code class="code">$9</code> using
+<code class="code">${<var class="var">num</var>}</code>.
-</li><li> The <small>POSIX</small> <code>$()</code> form of command substitution
-is implemented (see <a href="#Command-Substitution">Command Substitution</a>),
-and preferred to the Bourne shell’s <code>``</code> (which
+</li><li>The <small class="sc">POSIX</small> <code class="code">$()</code> form of command substitution
+is implemented (see <a class="pxref" href="#Command-Substitution">Command Substitution</a>),
+and preferred to the Bourne shell’s <code class="code">``</code> (which
is also implemented for backwards compatibility).
-</li><li> Bash has process substitution (see <a href="#Process-Substitution">Process Substitution</a>).
+</li><li>Bash has process substitution (see <a class="pxref" href="#Process-Substitution">Process Substitution</a>).
-</li><li> Bash automatically assigns variables that provide information about the
-current user (<code>UID</code>, <code>EUID</code>, and <code>GROUPS</code>), the current host
-(<code>HOSTTYPE</code>, <code>OSTYPE</code>, <code>MACHTYPE</code>, and <code>HOSTNAME</code>),
-and the instance of Bash that is running (<code>BASH</code>,
-<code>BASH_VERSION</code>, and <code>BASH_VERSINFO</code>). See <a href="#Bash-Variables">Bash Variables</a>,
+</li><li>Bash automatically assigns variables that provide information about the
+current user (<code class="env">UID</code>, <code class="env">EUID</code>, and <code class="env">GROUPS</code>), the current host
+(<code class="env">HOSTTYPE</code>, <code class="env">OSTYPE</code>, <code class="env">MACHTYPE</code>, and <code class="env">HOSTNAME</code>),
+and the instance of Bash that is running (<code class="env">BASH</code>,
+<code class="env">BASH_VERSION</code>, and <code class="env">BASH_VERSINFO</code>). See <a class="xref" href="#Bash-Variables">Bash Variables</a>,
for details.
-</li><li> The <code>IFS</code> variable is used to split only the results of expansion,
-not all words (see <a href="#Word-Splitting">Word Splitting</a>).
+</li><li>The <code class="env">IFS</code> variable is used to split only the results of expansion,
+not all words (see <a class="pxref" href="#Word-Splitting">Word Splitting</a>).
This closes a longstanding shell security hole.
-</li><li> The filename expansion bracket expression code uses ‘<samp>!</samp>’ and ‘<samp>^</samp>’
+</li><li>The filename expansion bracket expression code uses ‘<samp class="samp">!</samp>’ and ‘<samp class="samp">^</samp>’
to negate the set of characters between the brackets.
-The Bourne shell uses only ‘<samp>!</samp>’.
+The Bourne shell uses only ‘<samp class="samp">!</samp>’.
-</li><li> Bash implements the full set of <small>POSIX</small> filename expansion operators,
+</li><li>Bash implements the full set of <small class="sc">POSIX</small> filename expansion operators,
including character classes, equivalence classes, and
-collating symbols (see <a href="#Filename-Expansion">Filename Expansion</a>).
+collating symbols (see <a class="pxref" href="#Filename-Expansion">Filename Expansion</a>).
-</li><li> Bash implements extended pattern matching features when the <code>extglob</code>
-shell option is enabled (see <a href="#Pattern-Matching">Pattern Matching</a>).
+</li><li>Bash implements extended pattern matching features when the <code class="code">extglob</code>
+shell option is enabled (see <a class="pxref" href="#Pattern-Matching">Pattern Matching</a>).
-</li><li> It is possible to have a variable and a function with the same name;
-<code>sh</code> does not separate the two name spaces.
+</li><li>It is possible to have a variable and a function with the same name;
+<code class="code">sh</code> does not separate the two name spaces.
-</li><li> Bash functions are permitted to have local variables using the
-<code>local</code> builtin, and thus useful recursive functions may be written
-(see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+</li><li>Bash functions are permitted to have local variables using the
+<code class="code">local</code> builtin, and thus useful recursive functions may be written
+(see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> Variable assignments preceding commands affect only that command, even
-builtins and functions (see <a href="#Environment">Environment</a>).
-In <code>sh</code>, all variable assignments
+</li><li>Variable assignments preceding commands affect only that command, even
+builtins and functions (see <a class="pxref" href="#Environment">Environment</a>).
+In <code class="code">sh</code>, all variable assignments
preceding commands are global unless the command is executed from the
file system.
-</li><li> Bash performs filename expansion on filenames specified as operands
-to input and output redirection operators (see <a href="#Redirections">Redirections</a>).
+</li><li>Bash performs filename expansion on filenames specified as operands
+to input and output redirection operators (see <a class="pxref" href="#Redirections">Redirections</a>).
-</li><li> Bash contains the ‘<samp><></samp>’ redirection operator, allowing a file to be
-opened for both reading and writing, and the ‘<samp>&></samp>’ redirection
+</li><li>Bash contains the ‘<samp class="samp"><></samp>’ redirection operator, allowing a file to be
+opened for both reading and writing, and the ‘<samp class="samp">&></samp>’ redirection
operator, for directing standard output and standard error to the same
-file (see <a href="#Redirections">Redirections</a>).
+file (see <a class="pxref" href="#Redirections">Redirections</a>).
-</li><li> Bash includes the ‘<samp><<<</samp>’ redirection operator, allowing a string to
+</li><li>Bash includes the ‘<samp class="samp"><<<</samp>’ redirection operator, allowing a string to
be used as the standard input to a command.
-</li><li> Bash implements the ‘<samp>[n]<&<var>word</var></samp>’ and ‘<samp>[n]>&<var>word</var></samp>’
+</li><li>Bash implements the ‘<samp class="samp">[n]<&<var class="var">word</var></samp>’ and ‘<samp class="samp">[n]>&<var class="var">word</var></samp>’
redirection operators, which move one file descriptor to another.
-</li><li> Bash treats a number of filenames specially when they are
-used in redirection operators (see <a href="#Redirections">Redirections</a>).
+</li><li>Bash treats a number of filenames specially when they are
+used in redirection operators (see <a class="pxref" href="#Redirections">Redirections</a>).
-</li><li> Bash can open network connections to arbitrary machines and services
-with the redirection operators (see <a href="#Redirections">Redirections</a>).
+</li><li>Bash can open network connections to arbitrary machines and services
+with the redirection operators (see <a class="pxref" href="#Redirections">Redirections</a>).
-</li><li> The <code>noclobber</code> option is available to avoid overwriting existing
-files with output redirection (see <a href="#The-Set-Builtin">The Set Builtin</a>).
-The ‘<samp>>|</samp>’ redirection operator may be used to override <code>noclobber</code>.
+</li><li>The <code class="code">noclobber</code> option is available to avoid overwriting existing
+files with output redirection (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
+The ‘<samp class="samp">>|</samp>’ redirection operator may be used to override <code class="code">noclobber</code>.
-</li><li> The Bash <code>cd</code> and <code>pwd</code> builtins (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
-each take <samp>-L</samp> and <samp>-P</samp> options to switch between logical and
+</li><li>The Bash <code class="code">cd</code> and <code class="code">pwd</code> builtins (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
+each take <samp class="option">-L</samp> and <samp class="option">-P</samp> options to switch between logical and
physical modes.
-</li><li> Bash allows a function to override a builtin with the same name, and provides
+</li><li>Bash allows a function to override a builtin with the same name, and provides
access to that builtin’s functionality within the function via the
-<code>builtin</code> and <code>command</code> builtins (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+<code class="code">builtin</code> and <code class="code">command</code> builtins (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> The <code>command</code> builtin allows selective disabling of functions
-when command lookup is performed (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+</li><li>The <code class="code">command</code> builtin allows selective disabling of functions
+when command lookup is performed (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> Individual builtins may be enabled or disabled using the <code>enable</code>
-builtin (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+</li><li>Individual builtins may be enabled or disabled using the <code class="code">enable</code>
+builtin (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> The Bash <code>exec</code> builtin takes additional options that allow users
+</li><li>The Bash <code class="code">exec</code> builtin takes additional options that allow users
to control the contents of the environment passed to the executed
command, and what the zeroth argument to the command is to be
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-</li><li> Shell functions may be exported to children via the environment
-using <code>export -f</code> (see <a href="#Shell-Functions">Shell Functions</a>).
+</li><li>Shell functions may be exported to children via the environment
+using <code class="code">export -f</code> (see <a class="pxref" href="#Shell-Functions">Shell Functions</a>).
-</li><li> The Bash <code>export</code>, <code>readonly</code>, and <code>declare</code> builtins can
-take a <samp>-f</samp> option to act on shell functions, a <samp>-p</samp> option to
+</li><li>The Bash <code class="code">export</code>, <code class="code">readonly</code>, and <code class="code">declare</code> builtins can
+take a <samp class="option">-f</samp> option to act on shell functions, a <samp class="option">-p</samp> option to
display variables with various attributes set in a format that can be
-used as shell input, a <samp>-n</samp> option to remove various variable
-attributes, and ‘<samp>name=value</samp>’ arguments to set variable attributes
+used as shell input, a <samp class="option">-n</samp> option to remove various variable
+attributes, and ‘<samp class="samp">name=value</samp>’ arguments to set variable attributes
and values simultaneously.
-</li><li> The Bash <code>hash</code> builtin allows a name to be associated with
+</li><li>The Bash <code class="code">hash</code> builtin allows a name to be associated with
an arbitrary filename, even when that filename cannot be found by
-searching the <code>$PATH</code>, using ‘<samp>hash -p</samp>’
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+searching the <code class="env">$PATH</code>, using ‘<samp class="samp">hash -p</samp>’
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-</li><li> Bash includes a <code>help</code> builtin for quick reference to shell
-facilities (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+</li><li>Bash includes a <code class="code">help</code> builtin for quick reference to shell
+facilities (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> The <code>printf</code> builtin is available to display formatted output
-(see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+</li><li>The <code class="code">printf</code> builtin is available to display formatted output
+(see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> The Bash <code>read</code> builtin (see <a href="#Bash-Builtins">Bash Builtin Commands</a>)
-will read a line ending in ‘<samp>\</samp>’ with
-the <samp>-r</samp> option, and will use the <code>REPLY</code> variable as a
+</li><li>The Bash <code class="code">read</code> builtin (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>)
+will read a line ending in ‘<samp class="samp">\</samp>’ with
+the <samp class="option">-r</samp> option, and will use the <code class="env">REPLY</code> variable as a
default if no non-option arguments are supplied.
-The Bash <code>read</code> builtin
-also accepts a prompt string with the <samp>-p</samp> option and will use
-Readline to obtain the line when given the <samp>-e</samp> or <samp>-E</samp>
+The Bash <code class="code">read</code> builtin
+also accepts a prompt string with the <samp class="option">-p</samp> option and will use
+Readline to obtain the line when given the <samp class="option">-e</samp> or <samp class="option">-E</samp>
options.
-The <code>read</code> builtin also has additional options to control input:
-the <samp>-s</samp> option will turn off echoing of input characters as
-they are read, the <samp>-t</samp> option will allow <code>read</code> to time out
+The <code class="code">read</code> builtin also has additional options to control input:
+the <samp class="option">-s</samp> option will turn off echoing of input characters as
+they are read, the <samp class="option">-t</samp> option will allow <code class="code">read</code> to time out
if input does not arrive within a specified number of seconds, the
-<samp>-n</samp> option will allow reading only a specified number of
-characters rather than a full line, and the <samp>-d</samp> option will read
+<samp class="option">-n</samp> option will allow reading only a specified number of
+characters rather than a full line, and the <samp class="option">-d</samp> option will read
until a particular character rather than newline.
-</li><li> The <code>return</code> builtin may be used to abort execution of scripts
-executed with the <code>.</code> or <code>source</code> builtins
-(see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+</li><li>The <code class="code">return</code> builtin may be used to abort execution of scripts
+executed with the <code class="code">.</code> or <code class="code">source</code> builtins
+(see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-</li><li> Bash includes the <code>shopt</code> builtin, for finer control of shell
-optional capabilities (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), and allows these options
-to be set and unset at shell invocation (see <a href="#Invoking-Bash">Invoking Bash</a>).
+</li><li>Bash includes the <code class="code">shopt</code> builtin, for finer control of shell
+optional capabilities (see <a class="pxref" href="#The-Shopt-Builtin">The Shopt Builtin</a>), and allows these options
+to be set and unset at shell invocation (see <a class="pxref" href="#Invoking-Bash">Invoking Bash</a>).
-</li><li> Bash has much more optional behavior controllable with the <code>set</code>
-builtin (see <a href="#The-Set-Builtin">The Set Builtin</a>).
+</li><li>Bash has much more optional behavior controllable with the <code class="code">set</code>
+builtin (see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
-</li><li> The ‘<samp>-x</samp>’ (<samp>xtrace</samp>) option displays commands other than
+</li><li>The ‘<samp class="samp">-x</samp>’ (<samp class="option">xtrace</samp>) option displays commands other than
simple commands when performing an execution trace
-(see <a href="#The-Set-Builtin">The Set Builtin</a>).
+(see <a class="pxref" href="#The-Set-Builtin">The Set Builtin</a>).
-</li><li> The <code>test</code> builtin (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
-is slightly different, as it implements the <small>POSIX</small> algorithm,
+</li><li>The <code class="code">test</code> builtin (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>)
+is slightly different, as it implements the <small class="sc">POSIX</small> algorithm,
which specifies the behavior based on the number of arguments.
-</li><li> Bash includes the <code>caller</code> builtin, which displays the context of
+</li><li>Bash includes the <code class="code">caller</code> builtin, which displays the context of
any active subroutine call (a shell function or a script executed with
-the <code>.</code> or <code>source</code> builtins). This supports the Bash
+the <code class="code">.</code> or <code class="code">source</code> builtins). This supports the Bash
debugger.
-</li><li> The <code>trap</code> builtin (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>) allows a
-<code>DEBUG</code> pseudo-signal specification, similar to <code>EXIT</code>.
-Commands specified with a <code>DEBUG</code> trap are executed before every
-simple command, <code>for</code> command, <code>case</code> command,
-<code>select</code> command, every arithmetic <code>for</code> command, and before
+</li><li>The <code class="code">trap</code> builtin (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>) allows a
+<code class="code">DEBUG</code> pseudo-signal specification, similar to <code class="code">EXIT</code>.
+Commands specified with a <code class="code">DEBUG</code> trap are executed before every
+simple command, <code class="code">for</code> command, <code class="code">case</code> command,
+<code class="code">select</code> command, every arithmetic <code class="code">for</code> command, and before
the first command executes in a shell function.
-The <code>DEBUG</code> trap is not inherited by shell functions unless the
-function has been given the <code>trace</code> attribute or the
-<code>functrace</code> option has been enabled using the <code>shopt</code> builtin.
-The <code>extdebug</code> shell option has additional effects on the
-<code>DEBUG</code> trap.
-
-<p>The <code>trap</code> builtin (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>) allows an
-<code>ERR</code> pseudo-signal specification, similar to <code>EXIT</code> and <code>DEBUG</code>.
-Commands specified with an <code>ERR</code> trap are executed after a simple
+The <code class="code">DEBUG</code> trap is not inherited by shell functions unless the
+function has been given the <code class="code">trace</code> attribute or the
+<code class="code">functrace</code> option has been enabled using the <code class="code">shopt</code> builtin.
+The <code class="code">extdebug</code> shell option has additional effects on the
+<code class="code">DEBUG</code> trap.
+
+<p>The <code class="code">trap</code> builtin (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>) allows an
+<code class="code">ERR</code> pseudo-signal specification, similar to <code class="code">EXIT</code> and <code class="code">DEBUG</code>.
+Commands specified with an <code class="code">ERR</code> trap are executed after a simple
command fails, with a few exceptions.
-The <code>ERR</code> trap is not inherited by shell functions unless the
-<code>-o errtrace</code> option to the <code>set</code> builtin is enabled.
+The <code class="code">ERR</code> trap is not inherited by shell functions unless the
+<code class="code">-o errtrace</code> option to the <code class="code">set</code> builtin is enabled.
</p>
-<p>The <code>trap</code> builtin (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>) allows a
-<code>RETURN</code> pseudo-signal specification, similar to
-<code>EXIT</code> and <code>DEBUG</code>.
-Commands specified with a <code>RETURN</code> trap are executed before
+<p>The <code class="code">trap</code> builtin (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>) allows a
+<code class="code">RETURN</code> pseudo-signal specification, similar to
+<code class="code">EXIT</code> and <code class="code">DEBUG</code>.
+Commands specified with a <code class="code">RETURN</code> trap are executed before
execution resumes after a shell function or a shell script executed with
-<code>.</code> or <code>source</code> returns.
-The <code>RETURN</code> trap is not inherited by shell functions unless the
-function has been given the <code>trace</code> attribute or the
-<code>functrace</code> option has been enabled using the <code>shopt</code> builtin.
+<code class="code">.</code> or <code class="code">source</code> returns.
+The <code class="code">RETURN</code> trap is not inherited by shell functions unless the
+function has been given the <code class="code">trace</code> attribute or the
+<code class="code">functrace</code> option has been enabled using the <code class="code">shopt</code> builtin.
</p>
-</li><li> The Bash <code>type</code> builtin is more extensive and gives more information
-about the names it finds (see <a href="#Bash-Builtins">Bash Builtin Commands</a>).
+</li><li>The Bash <code class="code">type</code> builtin is more extensive and gives more information
+about the names it finds (see <a class="pxref" href="#Bash-Builtins">Bash Builtin Commands</a>).
-</li><li> The Bash <code>umask</code> builtin permits a <samp>-p</samp> option to cause
-the output to be displayed in the form of a <code>umask</code> command
-that may be reused as input (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
+</li><li>The Bash <code class="code">umask</code> builtin permits a <samp class="option">-p</samp> option to cause
+the output to be displayed in the form of a <code class="code">umask</code> command
+that may be reused as input (see <a class="pxref" href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>).
-</li><li> Bash implements a <code>csh</code>-like directory stack, and provides the
-<code>pushd</code>, <code>popd</code>, and <code>dirs</code> builtins to manipulate it
-(see <a href="#The-Directory-Stack">The Directory Stack</a>).
+</li><li>Bash implements a <code class="code">csh</code>-like directory stack, and provides the
+<code class="code">pushd</code>, <code class="code">popd</code>, and <code class="code">dirs</code> builtins to manipulate it
+(see <a class="pxref" href="#The-Directory-Stack">The Directory Stack</a>).
Bash also makes the directory stack visible as the value of the
-<code>DIRSTACK</code> shell variable.
+<code class="env">DIRSTACK</code> shell variable.
-</li><li> Bash interprets special backslash-escaped characters in the prompt
-strings when interactive (see <a href="#Controlling-the-Prompt">Controlling the Prompt</a>).
+</li><li>Bash interprets special backslash-escaped characters in the prompt
+strings when interactive (see <a class="pxref" href="#Controlling-the-Prompt">Controlling the Prompt</a>).
-</li><li> The Bash restricted mode is more useful (see <a href="#The-Restricted-Shell">The Restricted Shell</a>);
+</li><li>The Bash restricted mode is more useful (see <a class="pxref" href="#The-Restricted-Shell">The Restricted Shell</a>);
the SVR4.2 shell restricted mode is too limited.
-</li><li> The <code>disown</code> builtin can remove a job from the internal shell
-job table (see <a href="#Job-Control-Builtins">Job Control Builtins</a>) or suppress the sending
-of <code>SIGHUP</code> to a job when the shell exits as the result of a
-<code>SIGHUP</code>.
+</li><li>The <code class="code">disown</code> builtin can remove a job from the internal shell
+job table (see <a class="pxref" href="#Job-Control-Builtins">Job Control Builtins</a>) or suppress the sending
+of <code class="code">SIGHUP</code> to a job when the shell exits as the result of a
+<code class="code">SIGHUP</code>.
-</li><li> Bash includes a number of features to support a separate debugger for
+</li><li>Bash includes a number of features to support a separate debugger for
shell scripts.
-</li><li> The SVR4.2 shell has two privilege-related builtins
-(<code>mldmode</code> and <code>priv</code>) not present in Bash.
+</li><li>The SVR4.2 shell has two privilege-related builtins
+(<code class="code">mldmode</code> and <code class="code">priv</code>) not present in Bash.
-</li><li> Bash does not have the <code>stop</code> or <code>newgrp</code> builtins.
+</li><li>Bash does not have the <code class="code">stop</code> or <code class="code">newgrp</code> builtins.
-</li><li> Bash does not use the <code>SHACCT</code> variable or perform shell accounting.
+</li><li>Bash does not use the <code class="env">SHACCT</code> variable or perform shell accounting.
-</li><li> The SVR4.2 <code>sh</code> uses a <code>TIMEOUT</code> variable like Bash uses
-<code>TMOUT</code>.
+</li><li>The SVR4.2 <code class="code">sh</code> uses a <code class="env">TIMEOUT</code> variable like Bash uses
+<code class="env">TMOUT</code>.
</li></ul>
-<p>More features unique to Bash may be found in <a href="#Bash-Features">Bash Features</a>.
+<p>More features unique to Bash may be found in <a class="ref" href="#Bash-Features">Bash Features</a>.
</p>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Implementation-Differences-From-The-SVR4_002e2-Shell" accesskey="1">Implementation Differences From The SVR4.2 Shell</a></li>
</ul>
-<div class="appendixsec" id="Implementation-Differences-From-The-SVR4_002e2-Shell">
-<h3 class="appendixsec">B.1 Implementation Differences From The SVR4.2 Shell</h3>
+<div class="appendixsec-level-extent" id="Implementation-Differences-From-The-SVR4_002e2-Shell">
+<h3 class="appendixsec"><span>B.1 Implementation Differences From The SVR4.2 Shell<a class="copiable-link" href="#Implementation-Differences-From-The-SVR4_002e2-Shell"> ¶</a></span></h3>
<p>Since Bash is a completely new implementation, it does not suffer from
many of the limitations of the SVR4.2 shell. For instance:
</p>
-<ul>
-<li> Bash does not fork a subshell when redirecting into or out of
-a shell control structure such as an <code>if</code> or <code>while</code>
+<ul class="itemize mark-bullet">
+<li>Bash does not fork a subshell when redirecting into or out of
+a shell control structure such as an <code class="code">if</code> or <code class="code">while</code>
statement.
-</li><li> Bash does not allow unbalanced quotes. The SVR4.2 shell will silently
-insert a needed closing quote at <code>EOF</code> under certain circumstances.
+</li><li>Bash does not allow unbalanced quotes. The SVR4.2 shell will silently
+insert a needed closing quote at <code class="code">EOF</code> under certain circumstances.
This can be the cause of some hard-to-find errors.
-</li><li> The SVR4.2 shell uses a baroque memory management scheme based on
-trapping <code>SIGSEGV</code>. If the shell is started from a process with
-<code>SIGSEGV</code> blocked (e.g., by using the <code>system()</code> C library
+</li><li>The SVR4.2 shell uses a baroque memory management scheme based on
+trapping <code class="code">SIGSEGV</code>. If the shell is started from a process with
+<code class="code">SIGSEGV</code> blocked (e.g., by using the <code class="code">system()</code> C library
function call), it misbehaves badly.
-</li><li> In a questionable attempt at security, the SVR4.2 shell,
-when invoked without the <samp>-p</samp> option, will alter its real
-and effective <small>UID</small> and <small>GID</small> if they are less than some
+</li><li>In a questionable attempt at security, the SVR4.2 shell,
+when invoked without the <samp class="option">-p</samp> option, will alter its real
+and effective <small class="sc">UID</small> and <small class="sc">GID</small> if they are less than some
magic threshold value, commonly 100.
This can lead to unexpected results.
-</li><li> The SVR4.2 shell does not allow users to trap <code>SIGSEGV</code>,
-<code>SIGALRM</code>, or <code>SIGCHLD</code>.
+</li><li>The SVR4.2 shell does not allow users to trap <code class="code">SIGSEGV</code>,
+<code class="code">SIGALRM</code>, or <code class="code">SIGCHLD</code>.
-</li><li> The SVR4.2 shell does not allow the <code>IFS</code>, <code>MAILCHECK</code>,
-<code>PATH</code>, <code>PS1</code>, or <code>PS2</code> variables to be unset.
+</li><li>The SVR4.2 shell does not allow the <code class="env">IFS</code>, <code class="env">MAILCHECK</code>,
+<code class="env">PATH</code>, <code class="env">PS1</code>, or <code class="env">PS2</code> variables to be unset.
-</li><li> The SVR4.2 shell treats ‘<samp>^</samp>’ as the undocumented equivalent of
-‘<samp>|</samp>’.
+</li><li>The SVR4.2 shell treats ‘<samp class="samp">^</samp>’ as the undocumented equivalent of
+‘<samp class="samp">|</samp>’.
-</li><li> Bash allows multiple option arguments when it is invoked (<code>-x -v</code>);
-the SVR4.2 shell allows only one option argument (<code>-xv</code>). In
+</li><li>Bash allows multiple option arguments when it is invoked (<code class="code">-x -v</code>);
+the SVR4.2 shell allows only one option argument (<code class="code">-xv</code>). In
fact, some versions of the shell dump core if the second argument begins
-with a ‘<samp>-</samp>’.
+with a ‘<samp class="samp">-</samp>’.
-</li><li> The SVR4.2 shell exits a script if any builtin fails; Bash exits
-a script only if one of the <small>POSIX</small> special builtins fails, and
-only for certain failures, as enumerated in the <small>POSIX</small> standard.
+</li><li>The SVR4.2 shell exits a script if any builtin fails; Bash exits
+a script only if one of the <small class="sc">POSIX</small> special builtins fails, and
+only for certain failures, as enumerated in the <small class="sc">POSIX</small> standard.
-</li><li> The SVR4.2 shell behaves differently when invoked as <code>jsh</code>
+</li><li>The SVR4.2 shell behaves differently when invoked as <code class="code">jsh</code>
(it turns on job control).
</li></ul>
<hr>
</div>
</div>
-<div class="appendix" id="GNU-Free-Documentation-License">
-<div class="header">
+<div class="appendix-level-extent" id="GNU-Free-Documentation-License">
+<div class="nav-panel">
<p>
Next: <a href="#Indexes" accesskey="n" rel="next">Indexes</a>, Previous: <a href="#Major-Differences-From-The-Bourne-Shell" accesskey="p" rel="prev">Major Differences From The Bourne Shell</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="GNU-Free-Documentation-License-1"></span><h2 class="appendix">Appendix C GNU Free Documentation License</h2>
+<h2 class="appendix" id="GNU-Free-Documentation-License-1"><span>Appendix C GNU Free Documentation License<a class="copiable-link" href="#GNU-Free-Documentation-License-1"> ¶</a></span></h2>
-<div align="center">Version 1.3, 3 November 2008
+<div class="center">Version 1.3, 3 November 2008
</div>
<div class="display">
-<pre class="display">Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
-<a href="http://fsf.org/">http://fsf.org/</a>
+<pre class="display-preformatted">Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
+<a class="uref" href="http://fsf.org/">http://fsf.org/</a>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
</pre></div>
-<ol start="0">
+<ol class="enumerate" start="0">
<li> PREAMBLE
<p>The purpose of this License is to make a manual, textbook, or other
-functional and useful document <em>free</em> in the sense of freedom: to
+functional and useful document <em class="dfn">free</em> in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
of text. A copy that is not “Transparent” is called “Opaque”.
</p>
<p>Examples of suitable formats for Transparent copies include plain
-<small>ASCII</small> without markup, Texinfo input format, LaTeX input
-format, <acronym>SGML</acronym> or <acronym>XML</acronym> using a publicly available
-<acronym>DTD</acronym>, and standard-conforming simple <acronym>HTML</acronym>,
-PostScript or <acronym>PDF</acronym> designed for human modification. Examples
-of transparent image formats include <acronym>PNG</acronym>, <acronym>XCF</acronym> and
-<acronym>JPG</acronym>. Opaque formats include proprietary formats that can be
-read and edited only by proprietary word processors, <acronym>SGML</acronym> or
-<acronym>XML</acronym> for which the <acronym>DTD</acronym> and/or processing tools are
-not generally available, and the machine-generated <acronym>HTML</acronym>,
-PostScript or <acronym>PDF</acronym> produced by some word processors for
+<small class="sc">ASCII</small> without markup, Texinfo input format, LaTeX input
+format, <abbr class="acronym">SGML</abbr> or <abbr class="acronym">XML</abbr> using a publicly available
+<abbr class="acronym">DTD</abbr>, and standard-conforming simple <abbr class="acronym">HTML</abbr>,
+PostScript or <abbr class="acronym">PDF</abbr> designed for human modification. Examples
+of transparent image formats include <abbr class="acronym">PNG</abbr>, <abbr class="acronym">XCF</abbr> and
+<abbr class="acronym">JPG</abbr>. Opaque formats include proprietary formats that can be
+read and edited only by proprietary word processors, <abbr class="acronym">SGML</abbr> or
+<abbr class="acronym">XML</abbr> for which the <abbr class="acronym">DTD</abbr> and/or processing tools are
+not generally available, and the machine-generated <abbr class="acronym">HTML</abbr>,
+PostScript or <abbr class="acronym">PDF</abbr> produced by some word processors for
output purposes only.
</p>
<p>The “Title Page” means, for a printed book, the title page itself,
and modification of the Modified Version to whoever possesses a copy
of it. In addition, you must do these things in the Modified Version:
</p>
-<ol type="A" start="1">
+<ol class="enumerate" type="A" start="1">
<li> Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions
(which should, if there were any, be listed in the History section
of the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
-<a href="http://www.gnu.org/copyleft/">http://www.gnu.org/copyleft/</a>.
+<a class="uref" href="http://www.gnu.org/copyleft/">http://www.gnu.org/copyleft/</a>.
</p>
<p>Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
</p>
</li></ol>
-<span id="ADDENDUM_003a-How-to-use-this-License-for-your-documents"></span><h3 class="heading">ADDENDUM: How to use this License for your documents</h3>
+<h3 class="heading" id="ADDENDUM_003a-How-to-use-this-License-for-your-documents"><span>ADDENDUM: How to use this License for your documents<a class="copiable-link" href="#ADDENDUM_003a-How-to-use-this-License-for-your-documents"> ¶</a></span></h3>
<p>To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:
</p>
-<div class="example">
-<pre class="example"> Copyright (C) <var>year</var> <var>your name</var>.
+<div class="example smallexample">
+<div class="group"><pre class="example-preformatted"> Copyright (C) <var class="var">year</var> <var class="var">your name</var>.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
-</pre></div>
+</pre></div></div>
<p>If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the “with…Texts.” line with this:
</p>
-<div class="example">
-<pre class="example"> with the Invariant Sections being <var>list their titles</var>, with
- the Front-Cover Texts being <var>list</var>, and with the Back-Cover Texts
- being <var>list</var>.
-</pre></div>
+<div class="example smallexample">
+<div class="group"><pre class="example-preformatted"> with the Invariant Sections being <var class="var">list their titles</var>, with
+ the Front-Cover Texts being <var class="var">list</var>, and with the Back-Cover Texts
+ being <var class="var">list</var>.
+</pre></div></div>
<p>If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
<hr>
</div>
-<div class="appendix" id="Indexes">
-<div class="header">
+<div class="appendix-level-extent" id="Indexes">
+<div class="nav-panel">
<p>
Previous: <a href="#GNU-Free-Documentation-License" accesskey="p" rel="prev">GNU Free Documentation License</a>, Up: <a href="#Top" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Indexes-1"></span><h2 class="appendix">Appendix D Indexes</h2>
+<h2 class="appendix" id="Indexes-1"><span>Appendix D Indexes<a class="copiable-link" href="#Indexes-1"> ¶</a></span></h2>
-<ul class="section-toc">
+<ul class="mini-toc">
<li><a href="#Builtin-Index" accesskey="1">Index of Shell Builtin Commands</a></li>
<li><a href="#Reserved-Word-Index" accesskey="2">Index of Shell Reserved Words</a></li>
<li><a href="#Variable-Index" accesskey="3">Parameter and Variable Index</a></li>
<li><a href="#Concept-Index" accesskey="5">Concept Index</a></li>
</ul>
<hr>
-<div class="appendixsec" id="Builtin-Index">
-<div class="header">
+<div class="appendixsec-level-extent" id="Builtin-Index">
+<div class="nav-panel">
<p>
Next: <a href="#Reserved-Word-Index" accesskey="n" rel="next">Index of Shell Reserved Words</a>, Up: <a href="#Indexes" accesskey="u" rel="up">Indexes</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Index-of-Shell-Builtin-Commands"></span><h3 class="appendixsec">D.1 Index of Shell Builtin Commands</h3>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Builtin-Index_bt_symbol-1"><b>.</b></a>
+<h3 class="appendixsec" id="Index-of-Shell-Builtin-Commands"><span>D.1 Index of Shell Builtin Commands<a class="copiable-link" href="#Index-of-Shell-Builtin-Commands"> ¶</a></span></h3>
+<div class="printindex bt-printindex">
+<table class="bt-letters-header-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Builtin-Index_bt_symbol-1"><b>:</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_symbol-2"><b>:</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_symbol-2"><b>.</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_symbol-3"><b>[</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_symbol-3"><b>[</b></a>
<br>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-A"><b>A</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-G"><b>G</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-G"><b>G</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-J"><b>J</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-J"><b>J</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-L"><b>L</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-L"><b>L</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-W"><b>W</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-W"><b>W</b></a>
</td></tr></table>
-<table class="index-bt" border="0">
-<tr><td></td><th align="left">Index Entry</th><td> </td><th align="left"> Section</th></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_symbol-1">.</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_002e"><code>.</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_symbol-2">:</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_003a"><code>:</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_symbol-3">[</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_005b"><code>[</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-A">A</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-alias"><code>alias</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-B">B</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-bg"><code>bg</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-bind"><code>bind</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-break"><code>break</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-builtin"><code>builtin</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-C">C</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-caller"><code>caller</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-cd"><code>cd</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command"><code>command</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-compgen"><code>compgen</code></a>:</td><td> </td><td valign="top"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete"><code>complete</code></a>:</td><td> </td><td valign="top"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-compopt"><code>compopt</code></a>:</td><td> </td><td valign="top"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-continue"><code>continue</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-D">D</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-declare"><code>declare</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-dirs"><code>dirs</code></a>:</td><td> </td><td valign="top"><a href="#Directory-Stack-Builtins">Directory Stack Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-disown"><code>disown</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-E">E</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-echo"><code>echo</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-enable"><code>enable</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-eval"><code>eval</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-exec"><code>exec</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-exit"><code>exit</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-export"><code>export</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-F">F</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-false"><code>false</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-fc"><code>fc</code></a>:</td><td> </td><td valign="top"><a href="#Bash-History-Builtins">Bash History Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-fg"><code>fg</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-G">G</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-getopts"><code>getopts</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-H">H</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-hash"><code>hash</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-help"><code>help</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history"><code>history</code></a>:</td><td> </td><td valign="top"><a href="#Bash-History-Builtins">Bash History Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-J">J</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-jobs"><code>jobs</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-K">K</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-kill"><code>kill</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-L">L</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-let"><code>let</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-local"><code>local</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-logout"><code>logout</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-M">M</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-mapfile"><code>mapfile</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-P">P</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-popd"><code>popd</code></a>:</td><td> </td><td valign="top"><a href="#Directory-Stack-Builtins">Directory Stack Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-printf"><code>printf</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-pushd"><code>pushd</code></a>:</td><td> </td><td valign="top"><a href="#Directory-Stack-Builtins">Directory Stack Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-pwd"><code>pwd</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-R">R</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-read"><code>read</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-readarray"><code>readarray</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-readonly"><code>readonly</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-return"><code>return</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-S">S</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-set"><code>set</code></a>:</td><td> </td><td valign="top"><a href="#The-Set-Builtin">The Set Builtin</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shift"><code>shift</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shopt"><code>shopt</code></a>:</td><td> </td><td valign="top"><a href="#The-Shopt-Builtin">The Shopt Builtin</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-source"><code>source</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-suspend"><code>suspend</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-T">T</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-test"><code>test</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-times"><code>times</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-trap"><code>trap</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-true"><code>true</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-type"><code>type</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-typeset"><code>typeset</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-U">U</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-ulimit"><code>ulimit</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-umask"><code>umask</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-unalias"><code>unalias</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-unset"><code>unset</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Builtin-Index_bt_letter-W">W</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-wait"><code>wait</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
+<table class="bt-entries-printindex" border="0">
+<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_symbol-1">:</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_003a"><code>:</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_symbol-2">.</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_002e"><code>.</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_symbol-3">[</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_005b"><code>[</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-A">A</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-alias"><code>alias</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-B">B</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-bg"><code>bg</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-bind"><code>bind</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-break"><code>break</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-builtin"><code>builtin</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-C">C</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-caller"><code>caller</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-cd"><code>cd</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command"><code>command</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-compgen"><code>compgen</code></a></td><td class="printindex-index-section"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete"><code>complete</code></a></td><td class="printindex-index-section"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-compopt"><code>compopt</code></a></td><td class="printindex-index-section"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-continue"><code>continue</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-D">D</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-declare"><code>declare</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-dirs"><code>dirs</code></a></td><td class="printindex-index-section"><a href="#Directory-Stack-Builtins">Directory Stack Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-disown"><code>disown</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-E">E</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-echo"><code>echo</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-enable"><code>enable</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-eval"><code>eval</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-exec"><code>exec</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-exit"><code>exit</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-export"><code>export</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-F">F</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-false"><code>false</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-fc"><code>fc</code></a></td><td class="printindex-index-section"><a href="#Bash-History-Builtins">Bash History Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-fg"><code>fg</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-G">G</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-getopts"><code>getopts</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-H">H</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-hash"><code>hash</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-help"><code>help</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history"><code>history</code></a></td><td class="printindex-index-section"><a href="#Bash-History-Builtins">Bash History Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-J">J</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-jobs"><code>jobs</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-K">K</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-kill"><code>kill</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-L">L</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-let"><code>let</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-local"><code>local</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-logout"><code>logout</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-M">M</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-mapfile"><code>mapfile</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-P">P</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-popd"><code>popd</code></a></td><td class="printindex-index-section"><a href="#Directory-Stack-Builtins">Directory Stack Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-printf"><code>printf</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-pushd"><code>pushd</code></a></td><td class="printindex-index-section"><a href="#Directory-Stack-Builtins">Directory Stack Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-pwd"><code>pwd</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-R">R</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-read"><code>read</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-readarray"><code>readarray</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-readonly"><code>readonly</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-return"><code>return</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-S">S</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-set"><code>set</code></a></td><td class="printindex-index-section"><a href="#The-Set-Builtin">The Set Builtin</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shift"><code>shift</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shopt"><code>shopt</code></a></td><td class="printindex-index-section"><a href="#The-Shopt-Builtin">The Shopt Builtin</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-source"><code>source</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-suspend"><code>suspend</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-T">T</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-test"><code>test</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-times"><code>times</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-trap"><code>trap</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-true"><code>true</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-type"><code>type</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-typeset"><code>typeset</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-U">U</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-ulimit"><code>ulimit</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-umask"><code>umask</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-unalias"><code>unalias</code></a></td><td class="printindex-index-section"><a href="#Bash-Builtins">Bash Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-unset"><code>unset</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Builtin-Index_bt_letter-W">W</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-wait"><code>wait</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Builtins">Job Control Builtins</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
</table>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Builtin-Index_bt_symbol-1"><b>.</b></a>
+<table class="bt-letters-footer-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Builtin-Index_bt_symbol-1"><b>:</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_symbol-2"><b>:</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_symbol-2"><b>.</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_symbol-3"><b>[</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_symbol-3"><b>[</b></a>
<br>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-A"><b>A</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-G"><b>G</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-G"><b>G</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-J"><b>J</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-J"><b>J</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-L"><b>L</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-L"><b>L</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Builtin-Index_bt_letter-W"><b>W</b></a>
+<a class="summary-letter-printindex" href="#Builtin-Index_bt_letter-W"><b>W</b></a>
</td></tr></table>
+</div>
<hr>
</div>
-<div class="appendixsec" id="Reserved-Word-Index">
-<div class="header">
+<div class="appendixsec-level-extent" id="Reserved-Word-Index">
+<div class="nav-panel">
<p>
Next: <a href="#Variable-Index" accesskey="n" rel="next">Parameter and Variable Index</a>, Previous: <a href="#Builtin-Index" accesskey="p" rel="prev">Index of Shell Builtin Commands</a>, Up: <a href="#Indexes" accesskey="u" rel="up">Indexes</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Index-of-Shell-Reserved-Words"></span><h3 class="appendixsec">D.2 Index of Shell Reserved Words</h3>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-1"><b>!</b></a>
+<h3 class="appendixsec" id="Index-of-Shell-Reserved-Words"><span>D.2 Index of Shell Reserved Words<a class="copiable-link" href="#Index-of-Shell-Reserved-Words"> ¶</a></span></h3>
+<div class="printindex rw-printindex">
+<table class="rw-letters-header-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-1"><b>!</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-2"><b>[</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-2"><b>[</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-3"><b>]</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-3"><b>]</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-4"><b>{</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-4"><b>{</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-5"><b>}</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-5"><b>}</b></a>
<br>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-W"><b>W</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-W"><b>W</b></a>
</td></tr></table>
-<table class="index-rw" border="0">
-<tr><td></td><th align="left">Index Entry</th><td> </td><th align="left"> Section</th></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_symbol-1">!</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_0021"><code>!</code></a>:</td><td> </td><td valign="top"><a href="#Pipelines">Pipelines</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_symbol-2">[</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_005b_005b"><code>[[</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_symbol-3">]</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_005d_005d"><code>]]</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_symbol-4">{</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_007b"><code>{</code></a>:</td><td> </td><td valign="top"><a href="#Command-Grouping">Command Grouping</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_symbol-5">}</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_007d"><code>}</code></a>:</td><td> </td><td valign="top"><a href="#Command-Grouping">Command Grouping</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-C">C</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-case"><code>case</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-D">D</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-do"><code>do</code></a>:</td><td> </td><td valign="top"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-done"><code>done</code></a>:</td><td> </td><td valign="top"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-E">E</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-elif"><code>elif</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-else"><code>else</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-esac"><code>esac</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-F">F</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-fi"><code>fi</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-for"><code>for</code></a>:</td><td> </td><td valign="top"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-function"><code>function</code></a>:</td><td> </td><td valign="top"><a href="#Shell-Functions">Shell Functions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-I">I</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-if"><code>if</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-in"><code>in</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-S">S</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-select"><code>select</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-T">T</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-then"><code>then</code></a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-time"><code>time</code></a>:</td><td> </td><td valign="top"><a href="#Pipelines">Pipelines</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-U">U</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-until"><code>until</code></a>:</td><td> </td><td valign="top"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Reserved-Word-Index_rw_letter-W">W</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-while"><code>while</code></a>:</td><td> </td><td valign="top"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
+<table class="rw-entries-printindex" border="0">
+<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_symbol-1">!</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0021"><code>!</code></a></td><td class="printindex-index-section"><a href="#Pipelines">Pipelines</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_symbol-2">[</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_005b_005b"><code>[[</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_symbol-3">]</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_005d_005d"><code>]]</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_symbol-4">{</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_007b"><code>{</code></a></td><td class="printindex-index-section"><a href="#Command-Grouping">Command Grouping</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_symbol-5">}</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_007d"><code>}</code></a></td><td class="printindex-index-section"><a href="#Command-Grouping">Command Grouping</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-C">C</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-case"><code>case</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-D">D</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-do"><code>do</code></a></td><td class="printindex-index-section"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-done"><code>done</code></a></td><td class="printindex-index-section"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-E">E</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-elif"><code>elif</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-else"><code>else</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-esac"><code>esac</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-F">F</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-fi"><code>fi</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-for"><code>for</code></a></td><td class="printindex-index-section"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-function"><code>function</code></a></td><td class="printindex-index-section"><a href="#Shell-Functions">Shell Functions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-I">I</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-if"><code>if</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-in"><code>in</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-S">S</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-select"><code>select</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-T">T</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-then"><code>then</code></a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-time"><code>time</code></a></td><td class="printindex-index-section"><a href="#Pipelines">Pipelines</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-U">U</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-until"><code>until</code></a></td><td class="printindex-index-section"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Reserved-Word-Index_rw_letter-W">W</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-while"><code>while</code></a></td><td class="printindex-index-section"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
</table>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-1"><b>!</b></a>
+<table class="rw-letters-footer-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-1"><b>!</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-2"><b>[</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-2"><b>[</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-3"><b>]</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-3"><b>]</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-4"><b>{</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-4"><b>{</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_symbol-5"><b>}</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_symbol-5"><b>}</b></a>
<br>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Reserved-Word-Index_rw_letter-W"><b>W</b></a>
+<a class="summary-letter-printindex" href="#Reserved-Word-Index_rw_letter-W"><b>W</b></a>
</td></tr></table>
+</div>
<hr>
</div>
-<div class="appendixsec" id="Variable-Index">
-<div class="header">
+<div class="appendixsec-level-extent" id="Variable-Index">
+<div class="nav-panel">
<p>
Next: <a href="#Function-Index" accesskey="n" rel="next">Function Index</a>, Previous: <a href="#Reserved-Word-Index" accesskey="p" rel="prev">Index of Shell Reserved Words</a>, Up: <a href="#Indexes" accesskey="u" rel="up">Indexes</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Parameter-and-Variable-Index"></span><h3 class="appendixsec">D.3 Parameter and Variable Index</h3>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Variable-Index_vr_symbol-1"><b>!</b></a>
+<h3 class="appendixsec" id="Parameter-and-Variable-Index"><span>D.3 Parameter and Variable Index<a class="copiable-link" href="#Parameter-and-Variable-Index"> ¶</a></span></h3>
+<div class="printindex vr-printindex">
+<table class="vr-letters-header-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-1"><b>_</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-2"><b>#</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-2"><b>-</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-3"><b>$</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-3"><b>!</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-4"><b>*</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-4"><b>?</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-5"><b>-</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-5"><b>@</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-6"><b>0</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-6"><b>*</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-7"><b>?</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-7"><b>#</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-8"><b>@</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-8"><b>$</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-9"><b>_</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-9"><b>0</b></a>
<br>
-<a class="summary-letter" href="#Variable-Index_vr_letter-A"><b>A</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-G"><b>G</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-G"><b>G</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-L"><b>L</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-L"><b>L</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-O"><b>O</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-O"><b>O</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-V"><b>V</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-V"><b>V</b></a>
</td></tr></table>
-<table class="index-vr" border="0">
-<tr><td></td><th align="left">Index Entry</th><td> </td><th align="left"> Section</th></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-1">!</th><td></td><td></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0021-1"><code>!</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-2">#</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_0023"><code>#</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-3">$</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_0024"><code>$</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_0021"><code>$!</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_0023"><code>$#</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_0024_0024"><code>$$</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_002a"><code>$*</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_002d"><code>$-</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_00240"><code>$0</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_003f"><code>$?</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_0040"><code>$@</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_0024_005f"><code>$_</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-4">*</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_002a"><code>*</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-5">-</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_002d"><code>-</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-6">0</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-0"><code>0</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-7">?</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_003f"><code>?</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-8">@</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-_0040"><code>@</code></a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_symbol-9">_</th><td></td><td></td></tr>
-<tr><td></td><td valign="top"><a href="#index-_005f"><code>_</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-A">A</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-active_002dregion_002dend_002dcolor"><code>active-region-end-color</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-active_002dregion_002dstart_002dcolor"><code>active-region-start-color</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-auto_005fresume"><code>auto_resume</code></a>:</td><td> </td><td valign="top"><a href="#Job-Control-Variables">Job Control Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-B">B</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH"><code>BASH</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASHOPTS"><code>BASHOPTS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASHPID"><code>BASHPID</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fALIASES"><code>BASH_ALIASES</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fARGC"><code>BASH_ARGC</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fARGV"><code>BASH_ARGV</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fARGV0"><code>BASH_ARGV0</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fCMDS"><code>BASH_CMDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fCOMMAND"><code>BASH_COMMAND</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fCOMPAT"><code>BASH_COMPAT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fENV"><code>BASH_ENV</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fEXECUTION_005fSTRING"><code>BASH_EXECUTION_STRING</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fLINENO"><code>BASH_LINENO</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fLOADABLES_005fPATH"><code>BASH_LOADABLES_PATH</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fMONOSECONDS"><code>BASH_MONOSECONDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fREMATCH"><code>BASH_REMATCH</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fSOURCE"><code>BASH_SOURCE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fSUBSHELL"><code>BASH_SUBSHELL</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fTRAPSIG"><code>BASH_TRAPSIG</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fVERSINFO"><code>BASH_VERSINFO</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fVERSION"><code>BASH_VERSION</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-BASH_005fXTRACEFD"><code>BASH_XTRACEFD</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-bell_002dstyle"><code>bell-style</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-bind_002dtty_002dspecial_002dchars"><code>bind-tty-special-chars</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-blink_002dmatching_002dparen"><code>blink-matching-paren</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-C">C</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-CDPATH"><code>CDPATH</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-CHILD_005fMAX"><code>CHILD_MAX</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-colored_002dcompletion_002dprefix"><code>colored-completion-prefix</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-colored_002dstats"><code>colored-stats</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-COLUMNS"><code>COLUMNS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-comment_002dbegin"><code>comment-begin</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-completion_002ddisplay_002dwidth"><code>completion-display-width</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-completion_002dignore_002dcase"><code>completion-ignore-case</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-completion_002dmap_002dcase"><code>completion-map-case</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-completion_002dprefix_002ddisplay_002dlength"><code>completion-prefix-display-length</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-completion_002dquery_002ditems"><code>completion-query-items</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-COMPREPLY"><code>COMPREPLY</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-COMP_005fCWORD"><code>COMP_CWORD</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-COMP_005fKEY"><code>COMP_KEY</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-COMP_005fLINE"><code>COMP_LINE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-COMP_005fPOINT"><code>COMP_POINT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-COMP_005fTYPE"><code>COMP_TYPE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td valign="top"><a href="#index-COMP_005fWORDBREAKS"><code>COMP_WORDBREAKS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-COMP_005fWORDS"><code>COMP_WORDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-convert_002dmeta"><code>convert-meta</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-COPROC"><code>COPROC</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-D">D</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-DIRSTACK"><code>DIRSTACK</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-disable_002dcompletion"><code>disable-completion</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-E">E</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-echo_002dcontrol_002dcharacters"><code>echo-control-characters</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-editing_002dmode"><code>editing-mode</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-EMACS"><code>EMACS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-emacs_002dmode_002dstring"><code>emacs-mode-string</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-enable_002dactive_002dregion"><code>enable-active-region</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-enable_002dbracketed_002dpaste"><code>enable-bracketed-paste</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-enable_002dkeypad"><code>enable-keypad</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-ENV"><code>ENV</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-EPOCHREALTIME"><code>EPOCHREALTIME</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-EPOCHSECONDS"><code>EPOCHSECONDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-EUID"><code>EUID</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-EXECIGNORE"><code>EXECIGNORE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expand_002dtilde"><code>expand-tilde</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-F">F</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-FCEDIT"><code>FCEDIT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-FIGNORE"><code>FIGNORE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-FUNCNAME"><code>FUNCNAME</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-FUNCNEST"><code>FUNCNEST</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-G">G</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-GLOBIGNORE"><code>GLOBIGNORE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-GLOBSORT"><code>GLOBSORT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-GROUPS"><code>GROUPS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-H">H</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-histchars"><code>histchars</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTCMD"><code>HISTCMD</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTCONTROL"><code>HISTCONTROL</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTFILE"><code>HISTFILE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTFILESIZE"><code>HISTFILESIZE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTIGNORE"><code>HISTIGNORE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dpreserve_002dpoint"><code>history-preserve-point</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dsize"><code>history-size</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTSIZE"><code>HISTSIZE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HISTTIMEFORMAT"><code>HISTTIMEFORMAT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HOME"><code>HOME</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-horizontal_002dscroll_002dmode"><code>horizontal-scroll-mode</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HOSTFILE"><code>HOSTFILE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HOSTNAME"><code>HOSTNAME</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-HOSTTYPE"><code>HOSTTYPE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-I">I</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-IFS"><code>IFS</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-IGNOREEOF"><code>IGNOREEOF</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-input_002dmeta"><code>input-meta</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-INPUTRC"><code>INPUTRC</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-INSIDE_005fEMACS"><code>INSIDE_EMACS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-isearch_002dterminators"><code>isearch-terminators</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-K">K</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-keymap"><code>keymap</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-L">L</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LANG"><code>LANG</code></a>:</td><td> </td><td valign="top"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LANG-1"><code>LANG</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fALL"><code>LC_ALL</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fCOLLATE"><code>LC_COLLATE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fCTYPE"><code>LC_CTYPE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fMESSAGES"><code>LC_MESSAGES</code></a>:</td><td> </td><td valign="top"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fMESSAGES-1"><code>LC_MESSAGES</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fNUMERIC"><code>LC_NUMERIC</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LC_005fTIME"><code>LC_TIME</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LINENO"><code>LINENO</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-LINES"><code>LINES</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-M">M</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-MACHTYPE"><code>MACHTYPE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-MAIL"><code>MAIL</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-MAILCHECK"><code>MAILCHECK</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-MAILPATH"><code>MAILPATH</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-MAPFILE"><code>MAPFILE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-mark_002dmodified_002dlines"><code>mark-modified-lines</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-mark_002dsymlinked_002ddirectories"><code>mark-symlinked-directories</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-match_002dhidden_002dfiles"><code>match-hidden-files</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-menu_002dcomplete_002ddisplay_002dprefix"><code>menu-complete-display-prefix</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-meta_002dflag"><code>meta-flag</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-O">O</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-OLDPWD"><code>OLDPWD</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-OPTARG"><code>OPTARG</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-OPTERR"><code>OPTERR</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-OPTIND"><code>OPTIND</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-OSTYPE"><code>OSTYPE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-output_002dmeta"><code>output-meta</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-P">P</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-page_002dcompletions"><code>page-completions</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PATH"><code>PATH</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PIPESTATUS"><code>PIPESTATUS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-POSIXLY_005fCORRECT"><code>POSIXLY_CORRECT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PPID"><code>PPID</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PROMPT_005fCOMMAND"><code>PROMPT_COMMAND</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PROMPT_005fDIRTRIM"><code>PROMPT_DIRTRIM</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PS0"><code>PS0</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PS1"><code>PS1</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PS2"><code>PS2</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PS3"><code>PS3</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PS4"><code>PS4</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-PWD"><code>PWD</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-R">R</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-RANDOM"><code>RANDOM</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-READLINE_005fARGUMENT"><code>READLINE_ARGUMENT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-READLINE_005fLINE"><code>READLINE_LINE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-READLINE_005fMARK"><code>READLINE_MARK</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-READLINE_005fPOINT"><code>READLINE_POINT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-REPLY"><code>REPLY</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-revert_002dall_002dat_002dnewline"><code>revert-all-at-newline</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-S">S</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-search_002dignore_002dcase"><code>search-ignore-case</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-SECONDS"><code>SECONDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-SHELL"><code>SHELL</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-SHELLOPTS"><code>SHELLOPTS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-SHLVL"><code>SHLVL</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-show_002dall_002dif_002dambiguous"><code>show-all-if-ambiguous</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-show_002dall_002dif_002dunmodified"><code>show-all-if-unmodified</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-show_002dmode_002din_002dprompt"><code>show-mode-in-prompt</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-skip_002dcompleted_002dtext"><code>skip-completed-text</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-SRANDOM"><code>SRANDOM</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-T">T</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-TEXTDOMAIN"><code>TEXTDOMAIN</code></a>:</td><td> </td><td valign="top"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-TEXTDOMAINDIR"><code>TEXTDOMAINDIR</code></a>:</td><td> </td><td valign="top"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-TIMEFORMAT"><code>TIMEFORMAT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-TMOUT"><code>TMOUT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-TMPDIR"><code>TMPDIR</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-U">U</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-UID"><code>UID</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Variable-Index_vr_letter-V">V</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-vi_002dcmd_002dmode_002dstring"><code>vi-cmd-mode-string</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-vi_002dins_002dmode_002dstring"><code>vi-ins-mode-string</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-visible_002dstats"><code>visible-stats</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
+<table class="vr-entries-printindex" border="0">
+<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-1">_</th></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_005f"><code>_</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-2">-</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_002d"><code>-</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-3">!</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0021-1"><code>!</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-4">?</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_003f"><code>?</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-5">@</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0040"><code>@</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-6">*</th></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_002a"><code>*</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-7">#</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0023"><code>#</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-8">$</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0024"><code>$</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_0024_005f"><code>$_</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_0024_002d"><code>$-</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0024_0021"><code>$!</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_0024_003f"><code>$?</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_0024_0040"><code>$@</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_0024_002a"><code>$*</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_0024_0023"><code>$#</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-_0024_0024"><code>$$</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-_00240"><code>$0</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_symbol-9">0</th></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-0"><code>0</code></a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-A">A</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-active_002dregion_002dend_002dcolor"><code>active-region-end-color</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-active_002dregion_002dstart_002dcolor"><code>active-region-start-color</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-auto_005fresume"><code>auto_resume</code></a></td><td class="printindex-index-section"><a href="#Job-Control-Variables">Job Control Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-B">B</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH"><code>BASH</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fALIASES"><code>BASH_ALIASES</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fARGC"><code>BASH_ARGC</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fARGV"><code>BASH_ARGV</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fARGV0"><code>BASH_ARGV0</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fCMDS"><code>BASH_CMDS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fCOMMAND"><code>BASH_COMMAND</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fCOMPAT"><code>BASH_COMPAT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fENV"><code>BASH_ENV</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fEXECUTION_005fSTRING"><code>BASH_EXECUTION_STRING</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fLINENO"><code>BASH_LINENO</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fLOADABLES_005fPATH"><code>BASH_LOADABLES_PATH</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fMONOSECONDS"><code>BASH_MONOSECONDS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fREMATCH"><code>BASH_REMATCH</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fSOURCE"><code>BASH_SOURCE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fSUBSHELL"><code>BASH_SUBSHELL</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fTRAPSIG"><code>BASH_TRAPSIG</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fVERSINFO"><code>BASH_VERSINFO</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fVERSION"><code>BASH_VERSION</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASH_005fXTRACEFD"><code>BASH_XTRACEFD</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASHOPTS"><code>BASHOPTS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-BASHPID"><code>BASHPID</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-bell_002dstyle"><code>bell-style</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-bind_002dtty_002dspecial_002dchars"><code>bind-tty-special-chars</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-blink_002dmatching_002dparen"><code>blink-matching-paren</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-C">C</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-CDPATH"><code>CDPATH</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-CHILD_005fMAX"><code>CHILD_MAX</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-colored_002dcompletion_002dprefix"><code>colored-completion-prefix</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-colored_002dstats"><code>colored-stats</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-COLUMNS"><code>COLUMNS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-comment_002dbegin"><code>comment-begin</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-COMP_005fCWORD"><code>COMP_CWORD</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-COMP_005fKEY"><code>COMP_KEY</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-COMP_005fLINE"><code>COMP_LINE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-COMP_005fPOINT"><code>COMP_POINT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-COMP_005fTYPE"><code>COMP_TYPE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-COMP_005fWORDBREAKS"><code>COMP_WORDBREAKS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-COMP_005fWORDS"><code>COMP_WORDS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-completion_002ddisplay_002dwidth"><code>completion-display-width</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-completion_002dignore_002dcase"><code>completion-ignore-case</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-completion_002dmap_002dcase"><code>completion-map-case</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-completion_002dprefix_002ddisplay_002dlength"><code>completion-prefix-display-length</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td class="printindex-index-entry"><a href="#index-completion_002dquery_002ditems"><code>completion-query-items</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-COMPREPLY"><code>COMPREPLY</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-convert_002dmeta"><code>convert-meta</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-COPROC"><code>COPROC</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-D">D</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-DIRSTACK"><code>DIRSTACK</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-disable_002dcompletion"><code>disable-completion</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-E">E</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-echo_002dcontrol_002dcharacters"><code>echo-control-characters</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-editing_002dmode"><code>editing-mode</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-EMACS"><code>EMACS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-emacs_002dmode_002dstring"><code>emacs-mode-string</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-enable_002dactive_002dregion"><code>enable-active-region</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-enable_002dbracketed_002dpaste"><code>enable-bracketed-paste</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-enable_002dkeypad"><code>enable-keypad</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-ENV"><code>ENV</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-EPOCHREALTIME"><code>EPOCHREALTIME</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-EPOCHSECONDS"><code>EPOCHSECONDS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-EUID"><code>EUID</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-EXECIGNORE"><code>EXECIGNORE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expand_002dtilde"><code>expand-tilde</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-F">F</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-FCEDIT"><code>FCEDIT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-FIGNORE"><code>FIGNORE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-FUNCNAME"><code>FUNCNAME</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-FUNCNEST"><code>FUNCNEST</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-G">G</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-GLOBIGNORE"><code>GLOBIGNORE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-GLOBSORT"><code>GLOBSORT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-GROUPS"><code>GROUPS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-H">H</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-histchars"><code>histchars</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTCMD"><code>HISTCMD</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTCONTROL"><code>HISTCONTROL</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTFILE"><code>HISTFILE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTFILESIZE"><code>HISTFILESIZE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTIGNORE"><code>HISTIGNORE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dpreserve_002dpoint"><code>history-preserve-point</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dsize"><code>history-size</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTSIZE"><code>HISTSIZE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HISTTIMEFORMAT"><code>HISTTIMEFORMAT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HOME"><code>HOME</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-horizontal_002dscroll_002dmode"><code>horizontal-scroll-mode</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HOSTFILE"><code>HOSTFILE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HOSTNAME"><code>HOSTNAME</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-HOSTTYPE"><code>HOSTTYPE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-I">I</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-IFS"><code>IFS</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-IGNOREEOF"><code>IGNOREEOF</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-input_002dmeta"><code>input-meta</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-INPUTRC"><code>INPUTRC</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-INSIDE_005fEMACS"><code>INSIDE_EMACS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-isearch_002dterminators"><code>isearch-terminators</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-K">K</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-keymap"><code>keymap</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-L">L</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LANG"><code>LANG</code></a></td><td class="printindex-index-section"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LANG-1"><code>LANG</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fALL"><code>LC_ALL</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fCOLLATE"><code>LC_COLLATE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fCTYPE"><code>LC_CTYPE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fMESSAGES"><code>LC_MESSAGES</code></a></td><td class="printindex-index-section"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fMESSAGES-1"><code>LC_MESSAGES</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fNUMERIC"><code>LC_NUMERIC</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LC_005fTIME"><code>LC_TIME</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LINENO"><code>LINENO</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-LINES"><code>LINES</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-M">M</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-MACHTYPE"><code>MACHTYPE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-MAIL"><code>MAIL</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-MAILCHECK"><code>MAILCHECK</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-MAILPATH"><code>MAILPATH</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-MAPFILE"><code>MAPFILE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-mark_002dmodified_002dlines"><code>mark-modified-lines</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-mark_002dsymlinked_002ddirectories"><code>mark-symlinked-directories</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-match_002dhidden_002dfiles"><code>match-hidden-files</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-menu_002dcomplete_002ddisplay_002dprefix"><code>menu-complete-display-prefix</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-meta_002dflag"><code>meta-flag</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-O">O</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-OLDPWD"><code>OLDPWD</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-OPTARG"><code>OPTARG</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-OPTERR"><code>OPTERR</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-OPTIND"><code>OPTIND</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-OSTYPE"><code>OSTYPE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-output_002dmeta"><code>output-meta</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-P">P</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-page_002dcompletions"><code>page-completions</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PATH"><code>PATH</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PIPESTATUS"><code>PIPESTATUS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-POSIXLY_005fCORRECT"><code>POSIXLY_CORRECT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PPID"><code>PPID</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PROMPT_005fCOMMAND"><code>PROMPT_COMMAND</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PROMPT_005fDIRTRIM"><code>PROMPT_DIRTRIM</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PS0"><code>PS0</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PS1"><code>PS1</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PS2"><code>PS2</code></a></td><td class="printindex-index-section"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PS3"><code>PS3</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PS4"><code>PS4</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-PWD"><code>PWD</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-R">R</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-RANDOM"><code>RANDOM</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-READLINE_005fARGUMENT"><code>READLINE_ARGUMENT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-READLINE_005fLINE"><code>READLINE_LINE</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-READLINE_005fMARK"><code>READLINE_MARK</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-READLINE_005fPOINT"><code>READLINE_POINT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-REPLY"><code>REPLY</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-revert_002dall_002dat_002dnewline"><code>revert-all-at-newline</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-S">S</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-search_002dignore_002dcase"><code>search-ignore-case</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-SECONDS"><code>SECONDS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-SHELL"><code>SHELL</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-SHELLOPTS"><code>SHELLOPTS</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-SHLVL"><code>SHLVL</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-show_002dall_002dif_002dambiguous"><code>show-all-if-ambiguous</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-show_002dall_002dif_002dunmodified"><code>show-all-if-unmodified</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-show_002dmode_002din_002dprompt"><code>show-mode-in-prompt</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-skip_002dcompleted_002dtext"><code>skip-completed-text</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-SRANDOM"><code>SRANDOM</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-T">T</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-TEXTDOMAIN"><code>TEXTDOMAIN</code></a></td><td class="printindex-index-section"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-TEXTDOMAINDIR"><code>TEXTDOMAINDIR</code></a></td><td class="printindex-index-section"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-TIMEFORMAT"><code>TIMEFORMAT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-TMOUT"><code>TMOUT</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-TMPDIR"><code>TMPDIR</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-U">U</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-UID"><code>UID</code></a></td><td class="printindex-index-section"><a href="#Bash-Variables">Bash Variables</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Variable-Index_vr_letter-V">V</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-vi_002dcmd_002dmode_002dstring"><code>vi-cmd-mode-string</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-vi_002dins_002dmode_002dstring"><code>vi-ins-mode-string</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-visible_002dstats"><code>visible-stats</code></a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
</table>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Variable-Index_vr_symbol-1"><b>!</b></a>
+<table class="vr-letters-footer-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-1"><b>_</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-2"><b>#</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-2"><b>-</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-3"><b>$</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-3"><b>!</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-4"><b>*</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-4"><b>?</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-5"><b>-</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-5"><b>@</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-6"><b>0</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-6"><b>*</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-7"><b>?</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-7"><b>#</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-8"><b>@</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-8"><b>$</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_symbol-9"><b>_</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_symbol-9"><b>0</b></a>
<br>
-<a class="summary-letter" href="#Variable-Index_vr_letter-A"><b>A</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-G"><b>G</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-G"><b>G</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-L"><b>L</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-L"><b>L</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-O"><b>O</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-O"><b>O</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Variable-Index_vr_letter-V"><b>V</b></a>
+<a class="summary-letter-printindex" href="#Variable-Index_vr_letter-V"><b>V</b></a>
</td></tr></table>
+</div>
<hr>
</div>
-<div class="appendixsec" id="Function-Index">
-<div class="header">
+<div class="appendixsec-level-extent" id="Function-Index">
+<div class="nav-panel">
<p>
Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previous: <a href="#Variable-Index" accesskey="p" rel="prev">Parameter and Variable Index</a>, Up: <a href="#Indexes" accesskey="u" rel="up">Indexes</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Function-Index-1"></span><h3 class="appendixsec">D.4 Function Index</h3>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Function-Index_fn_letter-A"><b>A</b></a>
+<h3 class="appendixsec" id="Function-Index-1"><span>D.4 Function Index<a class="copiable-link" href="#Function-Index-1"> ¶</a></span></h3>
+<div class="printindex fn-printindex">
+<table class="fn-letters-header-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Function-Index_fn_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-G"><b>G</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-G"><b>G</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-N"><b>N</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-N"><b>N</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-O"><b>O</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-O"><b>O</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-Q"><b>Q</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-Q"><b>Q</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-Y"><b>Y</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-Y"><b>Y</b></a>
</td></tr></table>
-<table class="index-fn" border="0">
-<tr><td></td><th align="left">Index Entry</th><td> </td><th align="left"> Section</th></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-A">A</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-abort-_0028C_002dg_0029"><code>abort (C-g)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-accept_002dline-_0028Newline-or-Return_0029"><code>accept-line (Newline or Return)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-alias_002dexpand_002dline-_0028_0029"><code>alias-expand-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-B">B</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-backward_002dchar-_0028C_002db_0029"><code>backward-char (C-b)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-backward_002ddelete_002dchar-_0028Rubout_0029"><code>backward-delete-char (Rubout)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-backward_002dkill_002dline-_0028C_002dx-Rubout_0029"><code>backward-kill-line (C-x Rubout)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-backward_002dkill_002dword-_0028M_002dDEL_0029"><code>backward-kill-word (M-<span class="key">DEL</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-backward_002dword-_0028M_002db_0029"><code>backward-word (M-b)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-beginning_002dof_002dhistory-_0028M_002d_003c_0029"><code>beginning-of-history (M-<)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-beginning_002dof_002dline-_0028C_002da_0029"><code>beginning-of-line (C-a)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-bracketed_002dpaste_002dbegin-_0028_0029"><code>bracketed-paste-begin ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-C">C</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-call_002dlast_002dkbd_002dmacro-_0028C_002dx-e_0029"><code>call-last-kbd-macro (C-x e)</code></a>:</td><td> </td><td valign="top"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-capitalize_002dword-_0028M_002dc_0029"><code>capitalize-word (M-c)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-character_002dsearch-_0028C_002d_005d_0029"><code>character-search (C-])</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029"><code>character-search-backward (M-C-])</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-clear_002ddisplay-_0028M_002dC_002dl_0029"><code>clear-display (M-C-l)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-clear_002dscreen-_0028C_002dl_0029"><code>clear-screen (C-l)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete-_0028TAB_0029"><code>complete (<span class="key">TAB</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete_002dcommand-_0028M_002d_0021_0029"><code>complete-command (M-!)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete_002dfilename-_0028M_002d_002f_0029"><code>complete-filename (M-/)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete_002dhostname-_0028M_002d_0040_0029"><code>complete-hostname (M-@)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete_002dinto_002dbraces-_0028M_002d_007b_0029"><code>complete-into-braces (M-{)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete_002dusername-_0028M_002d_007e_0029"><code>complete-username (M-~)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-complete_002dvariable-_0028M_002d_0024_0029"><code>complete-variable (M-$)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-copy_002dbackward_002dword-_0028_0029"><code>copy-backward-word ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-copy_002dforward_002dword-_0028_0029"><code>copy-forward-word ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-copy_002dregion_002das_002dkill-_0028_0029"><code>copy-region-as-kill ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-D">D</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-dabbrev_002dexpand-_0028_0029"><code>dabbrev-expand ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-delete_002dchar-_0028C_002dd_0029"><code>delete-char (C-d)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-delete_002dchar_002dor_002dlist-_0028_0029"><code>delete-char-or-list ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-delete_002dhorizontal_002dspace-_0028_0029"><code>delete-horizontal-space ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029"><code>digit-argument (<kbd>M-0</kbd>, <kbd>M-1</kbd>, … <kbd>M--</kbd>)</code></a>:</td><td> </td><td valign="top"><a href="#Numeric-Arguments">Numeric Arguments</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029"><code>display-shell-version (C-x C-v)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029"><code>do-lowercase-version (M-A, M-B, M-<var>x</var>, …)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-downcase_002dword-_0028M_002dl_0029"><code>downcase-word (M-l)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-dump_002dfunctions-_0028_0029"><code>dump-functions ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-dump_002dmacros-_0028_0029"><code>dump-macros ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-dump_002dvariables-_0028_0029"><code>dump-variables ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029"><code>dynamic-complete-history (M-<span class="key">TAB</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-E">E</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"><code>edit-and-execute-command (C-x C-e)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029"><code>end-kbd-macro (C-x ))</code></a>:</td><td> </td><td valign="top"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-end_002dof_002dfile-_0028usually-C_002dd_0029"><code><i>end-of-file</i> (usually C-d)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-end_002dof_002dhistory-_0028M_002d_003e_0029"><code>end-of-history (M->)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-end_002dof_002dline-_0028C_002de_0029"><code>end-of-line (C-e)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-exchange_002dpoint_002dand_002dmark-_0028C_002dx-C_002dx_0029"><code>exchange-point-and-mark (C-x C-x)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-execute_002dnamed_002dcommand-_0028M_002dx_0029"><code>execute-named-command (M-x)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-F">F</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-fetch_002dhistory-_0028_0029"><code>fetch-history ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-forward_002dbackward_002ddelete_002dchar-_0028_0029"><code>forward-backward-delete-char ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-forward_002dchar-_0028C_002df_0029"><code>forward-char (C-f)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-forward_002dsearch_002dhistory-_0028C_002ds_0029"><code>forward-search-history (C-s)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-forward_002dword-_0028M_002df_0029"><code>forward-word (M-f)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-G">G</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-glob_002dcomplete_002dword-_0028M_002dg_0029"><code>glob-complete-word (M-g)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-glob_002dexpand_002dword-_0028C_002dx-_002a_0029"><code>glob-expand-word (C-x *)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-glob_002dlist_002dexpansions-_0028C_002dx-g_0029"><code>glob-list-expansions (C-x g)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-H">H</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dand_002dalias_002dexpand_002dline-_0028_0029"><code>history-and-alias-expand-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dexpand_002dline-_0028M_002d_005e_0029"><code>history-expand-line (M-^)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dsearch_002dbackward-_0028_0029"><code>history-search-backward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dsearch_002dforward-_0028_0029"><code>history-search-forward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dsubstring_002dsearch_002dbackward-_0028_0029"><code>history-substring-search-backward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history_002dsubstring_002dsearch_002dforward-_0028_0029"><code>history-substring-search-forward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-I">I</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-insert_002dcomment-_0028M_002d_0023_0029"><code>insert-comment (M-#)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-insert_002dcompletions-_0028M_002d_002a_0029"><code>insert-completions (M-*)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-insert_002dlast_002dargument-_0028M_002d_002e-or-M_002d_005f_0029"><code>insert-last-argument (M-. or M-_)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-K">K</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-kill_002dline-_0028C_002dk_0029"><code>kill-line (C-k)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-kill_002dregion-_0028_0029"><code>kill-region ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-kill_002dwhole_002dline-_0028_0029"><code>kill-whole-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-kill_002dword-_0028M_002dd_0029"><code>kill-word (M-d)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-M">M</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-magic_002dspace-_0028_0029"><code>magic-space ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-menu_002dcomplete-_0028_0029"><code>menu-complete ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-menu_002dcomplete_002dbackward-_0028_0029"><code>menu-complete-backward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-N">N</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-next_002dhistory-_0028C_002dn_0029"><code>next-history (C-n)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-next_002dscreen_002dline-_0028_0029"><code>next-screen-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029"><code>non-incremental-forward-search-history (M-n)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029"><code>non-incremental-reverse-search-history (M-p)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-O">O</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-operate_002dand_002dget_002dnext-_0028C_002do_0029"><code>operate-and-get-next (C-o)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-overwrite_002dmode-_0028_0029"><code>overwrite-mode ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-P">P</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-possible_002dcommand_002dcompletions-_0028C_002dx-_0021_0029"><code>possible-command-completions (C-x !)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-possible_002dcompletions-_0028M_002d_003f_0029"><code>possible-completions (M-?)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-possible_002dfilename_002dcompletions-_0028C_002dx-_002f_0029"><code>possible-filename-completions (C-x /)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-possible_002dhostname_002dcompletions-_0028C_002dx-_0040_0029"><code>possible-hostname-completions (C-x @)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-possible_002dusername_002dcompletions-_0028C_002dx-_007e_0029"><code>possible-username-completions (C-x ~)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029"><code>possible-variable-completions (C-x $)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-prefix_002dmeta-_0028ESC_0029"><code>prefix-meta (<span class="key">ESC</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-previous_002dhistory-_0028C_002dp_0029"><code>previous-history (C-p)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-previous_002dscreen_002dline-_0028_0029"><code>previous-screen-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-print_002dlast_002dkbd_002dmacro-_0028_0029"><code>print-last-kbd-macro ()</code></a>:</td><td> </td><td valign="top"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-Q">Q</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-quoted_002dinsert-_0028C_002dq-or-C_002dv_0029"><code>quoted-insert (C-q or C-v)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-R">R</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-re_002dread_002dinit_002dfile-_0028C_002dx-C_002dr_0029"><code>re-read-init-file (C-x C-r)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-redraw_002dcurrent_002dline-_0028_0029"><code>redraw-current-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-reverse_002dsearch_002dhistory-_0028C_002dr_0029"><code>reverse-search-history (C-r)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-revert_002dline-_0028M_002dr_0029"><code>revert-line (M-r)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-S">S</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-self_002dinsert-_0028a_002c-b_002c-A_002c-1_002c-_0021_002c-_2026_0029"><code>self-insert (a, b, A, 1, !, …)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-set_002dmark-_0028C_002d_0040_0029"><code>set-mark (C-@)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002dbackward_002dkill_002dword-_0028_0029"><code>shell-backward-kill-word ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002dbackward_002dword-_0028M_002dC_002db_0029"><code>shell-backward-word (M-C-b)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002dexpand_002dline-_0028M_002dC_002de_0029"><code>shell-expand-line (M-C-e)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002dforward_002dword-_0028M_002dC_002df_0029"><code>shell-forward-word (M-C-f)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002dkill_002dword-_0028M_002dC_002dd_0029"><code>shell-kill-word (M-C-d)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002dtranspose_002dwords-_0028M_002dC_002dt_0029"><code>shell-transpose-words (M-C-t)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-skip_002dcsi_002dsequence-_0028_0029"><code>skip-csi-sequence ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-spell_002dcorrect_002dword-_0028C_002dx-s_0029"><code>spell-correct-word (C-x s)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-start_002dkbd_002dmacro-_0028C_002dx-_0028_0029"><code>start-kbd-macro (C-x ()</code></a>:</td><td> </td><td valign="top"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-T">T</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-tilde_002dexpand-_0028M_002d_0026_0029"><code>tilde-expand (M-&)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-transpose_002dchars-_0028C_002dt_0029"><code>transpose-chars (C-t)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-transpose_002dwords-_0028M_002dt_0029"><code>transpose-words (M-t)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-U">U</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-undo-_0028C_002d_005f-or-C_002dx-C_002du_0029"><code>undo (C-_ or C-x C-u)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-universal_002dargument-_0028_0029"><code>universal-argument ()</code></a>:</td><td> </td><td valign="top"><a href="#Numeric-Arguments">Numeric Arguments</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-unix_002dfilename_002drubout-_0028_0029"><code>unix-filename-rubout ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-unix_002dline_002ddiscard-_0028C_002du_0029"><code>unix-line-discard (C-u)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-unix_002dword_002drubout-_0028C_002dw_0029"><code>unix-word-rubout (C-w)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-upcase_002dword-_0028M_002du_0029"><code>upcase-word (M-u)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Function-Index_fn_letter-Y">Y</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-yank-_0028C_002dy_0029"><code>yank (C-y)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-yank_002dlast_002darg-_0028M_002d_002e-or-M_002d_005f_0029"><code>yank-last-arg (M-. or M-_)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-yank_002dnth_002darg-_0028M_002dC_002dy_0029"><code>yank-nth-arg (M-C-y)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-yank_002dpop-_0028M_002dy_0029"><code>yank-pop (M-y)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
+<table class="fn-entries-printindex" border="0">
+<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-A">A</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-abort-_0028C_002dg_0029"><code>abort (C-g)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-accept_002dline-_0028Newline-or-Return_0029"><code>accept-line (Newline or Return)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-alias_002dexpand_002dline-_0028_0029"><code>alias-expand-line ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-B">B</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-backward_002dchar-_0028C_002db_0029"><code>backward-char (C-b)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-backward_002ddelete_002dchar-_0028Rubout_0029"><code>backward-delete-char (Rubout)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-backward_002dkill_002dline-_0028C_002dx-Rubout_0029"><code>backward-kill-line (C-x Rubout)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-backward_002dkill_002dword-_0028M_002dDEL_0029"><code>backward-kill-word (M-<kbd class="key">DEL</kbd>)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-backward_002dword-_0028M_002db_0029"><code>backward-word (M-b)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-beginning_002dof_002dhistory-_0028M_002d_003c_0029"><code>beginning-of-history (M-<)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-beginning_002dof_002dline-_0028C_002da_0029"><code>beginning-of-line (C-a)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-bracketed_002dpaste_002dbegin-_0028_0029"><code>bracketed-paste-begin ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-C">C</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-call_002dlast_002dkbd_002dmacro-_0028C_002dx-e_0029"><code>call-last-kbd-macro (C-x e)</code></a></td><td class="printindex-index-section"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-capitalize_002dword-_0028M_002dc_0029"><code>capitalize-word (M-c)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-character_002dsearch-_0028C_002d_005d_0029"><code>character-search (C-])</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029"><code>character-search-backward (M-C-])</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-clear_002ddisplay-_0028M_002dC_002dl_0029"><code>clear-display (M-C-l)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-clear_002dscreen-_0028C_002dl_0029"><code>clear-screen (C-l)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete-_0028TAB_0029"><code>complete (<kbd class="key">TAB</kbd>)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete_002dcommand-_0028M_002d_0021_0029"><code>complete-command (M-!)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete_002dfilename-_0028M_002d_002f_0029"><code>complete-filename (M-/)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete_002dhostname-_0028M_002d_0040_0029"><code>complete-hostname (M-@)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete_002dinto_002dbraces-_0028M_002d_007b_0029"><code>complete-into-braces (M-{)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete_002dusername-_0028M_002d_007e_0029"><code>complete-username (M-~)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-complete_002dvariable-_0028M_002d_0024_0029"><code>complete-variable (M-$)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-copy_002dbackward_002dword-_0028_0029"><code>copy-backward-word ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-copy_002dforward_002dword-_0028_0029"><code>copy-forward-word ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-copy_002dregion_002das_002dkill-_0028_0029"><code>copy-region-as-kill ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-D">D</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-dabbrev_002dexpand-_0028_0029"><code>dabbrev-expand ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-delete_002dchar-_0028C_002dd_0029"><code>delete-char (C-d)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-delete_002dchar_002dor_002dlist-_0028_0029"><code>delete-char-or-list ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-delete_002dhorizontal_002dspace-_0028_0029"><code>delete-horizontal-space ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029"><code>digit-argument (<kbd class="kbd">M-0</kbd>, <kbd class="kbd">M-1</kbd>, … <kbd class="kbd">M--</kbd>)</code></a></td><td class="printindex-index-section"><a href="#Numeric-Arguments">Numeric Arguments</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029"><code>display-shell-version (C-x C-v)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029"><code>do-lowercase-version (M-A, M-B, M-<var class="var">x</var>, …)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-downcase_002dword-_0028M_002dl_0029"><code>downcase-word (M-l)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-dump_002dfunctions-_0028_0029"><code>dump-functions ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-dump_002dmacros-_0028_0029"><code>dump-macros ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-dump_002dvariables-_0028_0029"><code>dump-variables ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029"><code>dynamic-complete-history (M-<kbd class="key">TAB</kbd>)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-E">E</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"><code>edit-and-execute-command (C-x C-e)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029"><code>end-kbd-macro (C-x ))</code></a></td><td class="printindex-index-section"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-end_002dof_002dfile-_0028usually-C_002dd_0029"><code><i class="i">end-of-file</i> (usually C-d)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-end_002dof_002dhistory-_0028M_002d_003e_0029"><code>end-of-history (M->)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-end_002dof_002dline-_0028C_002de_0029"><code>end-of-line (C-e)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-exchange_002dpoint_002dand_002dmark-_0028C_002dx-C_002dx_0029"><code>exchange-point-and-mark (C-x C-x)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-execute_002dnamed_002dcommand-_0028M_002dx_0029"><code>execute-named-command (M-x)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-F">F</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-fetch_002dhistory-_0028_0029"><code>fetch-history ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-forward_002dbackward_002ddelete_002dchar-_0028_0029"><code>forward-backward-delete-char ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-forward_002dchar-_0028C_002df_0029"><code>forward-char (C-f)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-forward_002dsearch_002dhistory-_0028C_002ds_0029"><code>forward-search-history (C-s)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-forward_002dword-_0028M_002df_0029"><code>forward-word (M-f)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-G">G</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-glob_002dcomplete_002dword-_0028M_002dg_0029"><code>glob-complete-word (M-g)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-glob_002dexpand_002dword-_0028C_002dx-_002a_0029"><code>glob-expand-word (C-x *)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-glob_002dlist_002dexpansions-_0028C_002dx-g_0029"><code>glob-list-expansions (C-x g)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-H">H</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dand_002dalias_002dexpand_002dline-_0028_0029"><code>history-and-alias-expand-line ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dexpand_002dline-_0028M_002d_005e_0029"><code>history-expand-line (M-^)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dsearch_002dbackward-_0028_0029"><code>history-search-backward ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dsearch_002dforward-_0028_0029"><code>history-search-forward ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dsubstring_002dsearch_002dbackward-_0028_0029"><code>history-substring-search-backward ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history_002dsubstring_002dsearch_002dforward-_0028_0029"><code>history-substring-search-forward ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-I">I</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-insert_002dcomment-_0028M_002d_0023_0029"><code>insert-comment (M-#)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-insert_002dcompletions-_0028M_002d_002a_0029"><code>insert-completions (M-*)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-insert_002dlast_002dargument-_0028M_002d_002e-or-M_002d_005f_0029"><code>insert-last-argument (M-. or M-_)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-K">K</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-kill_002dline-_0028C_002dk_0029"><code>kill-line (C-k)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-kill_002dregion-_0028_0029"><code>kill-region ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-kill_002dwhole_002dline-_0028_0029"><code>kill-whole-line ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-kill_002dword-_0028M_002dd_0029"><code>kill-word (M-d)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-M">M</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-magic_002dspace-_0028_0029"><code>magic-space ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-menu_002dcomplete-_0028_0029"><code>menu-complete ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-menu_002dcomplete_002dbackward-_0028_0029"><code>menu-complete-backward ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-N">N</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-next_002dhistory-_0028C_002dn_0029"><code>next-history (C-n)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-next_002dscreen_002dline-_0028_0029"><code>next-screen-line ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029"><code>non-incremental-forward-search-history (M-n)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029"><code>non-incremental-reverse-search-history (M-p)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-O">O</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-operate_002dand_002dget_002dnext-_0028C_002do_0029"><code>operate-and-get-next (C-o)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-overwrite_002dmode-_0028_0029"><code>overwrite-mode ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-P">P</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-possible_002dcommand_002dcompletions-_0028C_002dx-_0021_0029"><code>possible-command-completions (C-x !)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-possible_002dcompletions-_0028M_002d_003f_0029"><code>possible-completions (M-?)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-possible_002dfilename_002dcompletions-_0028C_002dx-_002f_0029"><code>possible-filename-completions (C-x /)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-possible_002dhostname_002dcompletions-_0028C_002dx-_0040_0029"><code>possible-hostname-completions (C-x @)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-possible_002dusername_002dcompletions-_0028C_002dx-_007e_0029"><code>possible-username-completions (C-x ~)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029"><code>possible-variable-completions (C-x $)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-prefix_002dmeta-_0028ESC_0029"><code>prefix-meta (<kbd class="key">ESC</kbd>)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-previous_002dhistory-_0028C_002dp_0029"><code>previous-history (C-p)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-previous_002dscreen_002dline-_0028_0029"><code>previous-screen-line ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-print_002dlast_002dkbd_002dmacro-_0028_0029"><code>print-last-kbd-macro ()</code></a></td><td class="printindex-index-section"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-Q">Q</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-quoted_002dinsert-_0028C_002dq-or-C_002dv_0029"><code>quoted-insert (C-q or C-v)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-R">R</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-re_002dread_002dinit_002dfile-_0028C_002dx-C_002dr_0029"><code>re-read-init-file (C-x C-r)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-redraw_002dcurrent_002dline-_0028_0029"><code>redraw-current-line ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-reverse_002dsearch_002dhistory-_0028C_002dr_0029"><code>reverse-search-history (C-r)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-revert_002dline-_0028M_002dr_0029"><code>revert-line (M-r)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-S">S</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-self_002dinsert-_0028a_002c-b_002c-A_002c-1_002c-_0021_002c-_2026_0029"><code>self-insert (a, b, A, 1, !, …)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-set_002dmark-_0028C_002d_0040_0029"><code>set-mark (C-@)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002dbackward_002dkill_002dword-_0028_0029"><code>shell-backward-kill-word ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002dbackward_002dword-_0028M_002dC_002db_0029"><code>shell-backward-word (M-C-b)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002dexpand_002dline-_0028M_002dC_002de_0029"><code>shell-expand-line (M-C-e)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002dforward_002dword-_0028M_002dC_002df_0029"><code>shell-forward-word (M-C-f)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002dkill_002dword-_0028M_002dC_002dd_0029"><code>shell-kill-word (M-C-d)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002dtranspose_002dwords-_0028M_002dC_002dt_0029"><code>shell-transpose-words (M-C-t)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-skip_002dcsi_002dsequence-_0028_0029"><code>skip-csi-sequence ()</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-spell_002dcorrect_002dword-_0028C_002dx-s_0029"><code>spell-correct-word (C-x s)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-start_002dkbd_002dmacro-_0028C_002dx-_0028_0029"><code>start-kbd-macro (C-x ()</code></a></td><td class="printindex-index-section"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-T">T</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-tilde_002dexpand-_0028M_002d_0026_0029"><code>tilde-expand (M-&)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-transpose_002dchars-_0028C_002dt_0029"><code>transpose-chars (C-t)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-transpose_002dwords-_0028M_002dt_0029"><code>transpose-words (M-t)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-U">U</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-undo-_0028C_002d_005f-or-C_002dx-C_002du_0029"><code>undo (C-_ or C-x C-u)</code></a></td><td class="printindex-index-section"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-universal_002dargument-_0028_0029"><code>universal-argument ()</code></a></td><td class="printindex-index-section"><a href="#Numeric-Arguments">Numeric Arguments</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-unix_002dfilename_002drubout-_0028_0029"><code>unix-filename-rubout ()</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-unix_002dline_002ddiscard-_0028C_002du_0029"><code>unix-line-discard (C-u)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-unix_002dword_002drubout-_0028C_002dw_0029"><code>unix-word-rubout (C-w)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-upcase_002dword-_0028M_002du_0029"><code>upcase-word (M-u)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Function-Index_fn_letter-Y">Y</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-yank-_0028C_002dy_0029"><code>yank (C-y)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-yank_002dlast_002darg-_0028M_002d_002e-or-M_002d_005f_0029"><code>yank-last-arg (M-. or M-_)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-yank_002dnth_002darg-_0028M_002dC_002dy_0029"><code>yank-nth-arg (M-C-y)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-History">Commands For History</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-yank_002dpop-_0028M_002dy_0029"><code>yank-pop (M-y)</code></a></td><td class="printindex-index-section"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
</table>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Function-Index_fn_letter-A"><b>A</b></a>
+<table class="fn-letters-footer-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Function-Index_fn_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-G"><b>G</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-G"><b>G</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-N"><b>N</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-N"><b>N</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-O"><b>O</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-O"><b>O</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-Q"><b>Q</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-Q"><b>Q</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Function-Index_fn_letter-Y"><b>Y</b></a>
+<a class="summary-letter-printindex" href="#Function-Index_fn_letter-Y"><b>Y</b></a>
</td></tr></table>
+</div>
<hr>
</div>
-<div class="appendixsec" id="Concept-Index">
-<div class="header">
+<div class="appendixsec-level-extent" id="Concept-Index">
+<div class="nav-panel">
<p>
Previous: <a href="#Function-Index" accesskey="p" rel="prev">Function Index</a>, Up: <a href="#Indexes" accesskey="u" rel="up">Indexes</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
</div>
-<span id="Concept-Index-1"></span><h3 class="appendixsec">D.5 Concept Index</h3>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Concept-Index_cp_letter-A"><b>A</b></a>
+<h3 class="appendixsec" id="Concept-Index-1"><span>D.5 Concept Index<a class="copiable-link" href="#Concept-Index-1"> ¶</a></span></h3>
+<div class="printindex cp-printindex">
+<table class="cp-letters-header-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Concept-Index_cp_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-J"><b>J</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-J"><b>J</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-L"><b>L</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-L"><b>L</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-N"><b>N</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-N"><b>N</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-O"><b>O</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-O"><b>O</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-Q"><b>Q</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-Q"><b>Q</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-V"><b>V</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-V"><b>V</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-W"><b>W</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-W"><b>W</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-Y"><b>Y</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-Y"><b>Y</b></a>
</td></tr></table>
-<table class="index-cp" border="0">
-<tr><td></td><th align="left">Index Entry</th><td> </td><th align="left"> Section</th></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-A">A</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-alias-expansion">alias expansion</a>:</td><td> </td><td valign="top"><a href="#Aliases">Aliases</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-arithmetic-evaluation">arithmetic evaluation</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-arithmetic-expansion">arithmetic expansion</a>:</td><td> </td><td valign="top"><a href="#Arithmetic-Expansion">Arithmetic Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-arithmetic-operators">arithmetic operators</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-arithmetic_002c-shell">arithmetic, shell</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-arrays">arrays</a>:</td><td> </td><td valign="top"><a href="#Arrays">Arrays</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-B">B</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-background">background</a>:</td><td> </td><td valign="top"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-Bash-configuration">Bash configuration</a>:</td><td> </td><td valign="top"><a href="#Basic-Installation">Basic Installation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-Bash-installation">Bash installation</a>:</td><td> </td><td valign="top"><a href="#Basic-Installation">Basic Installation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-binary-arithmetic-operators">binary arithmetic operators</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-bitwise-arithmetic-operators">bitwise arithmetic operators</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-Bourne-shell">Bourne shell</a>:</td><td> </td><td valign="top"><a href="#Basic-Shell-Features">Basic Shell Features</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-brace-expansion">brace expansion</a>:</td><td> </td><td valign="top"><a href="#Brace-Expansion">Brace Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-builtin-1">builtin</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-C">C</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-editing">command editing</a>:</td><td> </td><td valign="top"><a href="#Readline-Bare-Essentials">Readline Bare Essentials</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-execution">command execution</a>:</td><td> </td><td valign="top"><a href="#Command-Search-and-Execution">Command Search and Execution</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-expansion">command expansion</a>:</td><td> </td><td valign="top"><a href="#Simple-Command-Expansion">Simple Command Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-history">command history</a>:</td><td> </td><td valign="top"><a href="#Bash-History-Facilities">Bash History Facilities</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-search">command search</a>:</td><td> </td><td valign="top"><a href="#Command-Search-and-Execution">Command Search and Execution</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-substitution">command substitution</a>:</td><td> </td><td valign="top"><a href="#Command-Substitution">Command Substitution</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-command-timing">command timing</a>:</td><td> </td><td valign="top"><a href="#Pipelines">Pipelines</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-compound">commands, compound</a>:</td><td> </td><td valign="top"><a href="#Compound-Commands">Compound Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-conditional">commands, conditional</a>:</td><td> </td><td valign="top"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-grouping">commands, grouping</a>:</td><td> </td><td valign="top"><a href="#Command-Grouping">Command Grouping</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-lists">commands, lists</a>:</td><td> </td><td valign="top"><a href="#Lists">Lists</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-looping">commands, looping</a>:</td><td> </td><td valign="top"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-pipelines">commands, pipelines</a>:</td><td> </td><td valign="top"><a href="#Pipelines">Pipelines</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-shell">commands, shell</a>:</td><td> </td><td valign="top"><a href="#Shell-Commands">Shell Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-commands_002c-simple">commands, simple</a>:</td><td> </td><td valign="top"><a href="#Simple-Commands">Simple Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-comments_002c-shell">comments, shell</a>:</td><td> </td><td valign="top"><a href="#Comments">Comments</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-Compatibility-Level">Compatibility Level</a>:</td><td> </td><td valign="top"><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-Compatibility-Mode">Compatibility Mode</a>:</td><td> </td><td valign="top"><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-completion-builtins">completion builtins</a>:</td><td> </td><td valign="top"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-conditional-arithmetic-operator">conditional arithmetic operator</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-configuration">configuration</a>:</td><td> </td><td valign="top"><a href="#Basic-Installation">Basic Installation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-control-operator">control operator</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-coprocess">coprocess</a>:</td><td> </td><td valign="top"><a href="#Coprocesses">Coprocesses</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-D">D</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-directory-stack">directory stack</a>:</td><td> </td><td valign="top"><a href="#The-Directory-Stack">The Directory Stack</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-E">E</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-editing-command-lines">editing command lines</a>:</td><td> </td><td valign="top"><a href="#Readline-Bare-Essentials">Readline Bare Essentials</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-environment">environment</a>:</td><td> </td><td valign="top"><a href="#Environment">Environment</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-evaluation_002c-arithmetic">evaluation, arithmetic</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-event-designators">event designators</a>:</td><td> </td><td valign="top"><a href="#Event-Designators">Event Designators</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-execution-environment">execution environment</a>:</td><td> </td><td valign="top"><a href="#Command-Execution-Environment">Command Execution Environment</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-exit-status">exit status</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-exit-status-1">exit status</a>:</td><td> </td><td valign="top"><a href="#Exit-Status">Exit Status</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion">expansion</a>:</td><td> </td><td valign="top"><a href="#Shell-Expansions">Shell Expansions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion_002c-arithmetic">expansion, arithmetic</a>:</td><td> </td><td valign="top"><a href="#Arithmetic-Expansion">Arithmetic Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion_002c-brace">expansion, brace</a>:</td><td> </td><td valign="top"><a href="#Brace-Expansion">Brace Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion_002c-filename">expansion, filename</a>:</td><td> </td><td valign="top"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion_002c-parameter">expansion, parameter</a>:</td><td> </td><td valign="top"><a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion_002c-pathname">expansion, pathname</a>:</td><td> </td><td valign="top"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expansion_002c-tilde">expansion, tilde</a>:</td><td> </td><td valign="top"><a href="#Tilde-Expansion">Tilde Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expressions_002c-arithmetic">expressions, arithmetic</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-expressions_002c-conditional">expressions, conditional</a>:</td><td> </td><td valign="top"><a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-F">F</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-field">field</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-filename">filename</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-filename-expansion">filename expansion</a>:</td><td> </td><td valign="top"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-foreground">foreground</a>:</td><td> </td><td valign="top"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-functions_002c-shell">functions, shell</a>:</td><td> </td><td valign="top"><a href="#Shell-Functions">Shell Functions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-H">H</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history-builtins">history builtins</a>:</td><td> </td><td valign="top"><a href="#Bash-History-Builtins">Bash History Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history-events">history events</a>:</td><td> </td><td valign="top"><a href="#Event-Designators">Event Designators</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history-expansion">history expansion</a>:</td><td> </td><td valign="top"><a href="#History-Interaction">History Interaction</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-history-list">history list</a>:</td><td> </td><td valign="top"><a href="#Bash-History-Facilities">Bash History Facilities</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-History_002c-how-to-use">History, how to use</a>:</td><td> </td><td valign="top"><a href="#A-Programmable-Completion-Example">A Programmable Completion Example</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-I">I</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-identifier">identifier</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-initialization-file_002c-readline">initialization file, readline</a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File">Readline Init File</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-installation">installation</a>:</td><td> </td><td valign="top"><a href="#Basic-Installation">Basic Installation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-interaction_002c-readline">interaction, readline</a>:</td><td> </td><td valign="top"><a href="#Readline-Interaction">Readline Interaction</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-interactive-shell">interactive shell</a>:</td><td> </td><td valign="top"><a href="#Invoking-Bash">Invoking Bash</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-interactive-shell-1">interactive shell</a>:</td><td> </td><td valign="top"><a href="#Interactive-Shells">Interactive Shells</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-internationalization">internationalization</a>:</td><td> </td><td valign="top"><a href="#Locale-Translation">Locale Translation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-internationalized-scripts">internationalized scripts</a>:</td><td> </td><td valign="top"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-J">J</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-job">job</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-job-control">job control</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-job-control-1">job control</a>:</td><td> </td><td valign="top"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-K">K</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-kill-ring">kill ring</a>:</td><td> </td><td valign="top"><a href="#Readline-Killing-Commands">Readline Killing Commands</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-killing-text">killing text</a>:</td><td> </td><td valign="top"><a href="#Readline-Killing-Commands">Readline Killing Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-L">L</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-localization">localization</a>:</td><td> </td><td valign="top"><a href="#Locale-Translation">Locale Translation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-login-shell">login shell</a>:</td><td> </td><td valign="top"><a href="#Invoking-Bash">Invoking Bash</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-M">M</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-matching_002c-pattern">matching, pattern</a>:</td><td> </td><td valign="top"><a href="#Pattern-Matching">Pattern Matching</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-metacharacter">metacharacter</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-N">N</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-name">name</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-native-languages">native languages</a>:</td><td> </td><td valign="top"><a href="#Locale-Translation">Locale Translation</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-notation_002c-readline">notation, readline</a>:</td><td> </td><td valign="top"><a href="#Readline-Bare-Essentials">Readline Bare Essentials</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-O">O</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-operator_002c-shell">operator, shell</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-P">P</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-parameter-expansion">parameter expansion</a>:</td><td> </td><td valign="top"><a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-parameters">parameters</a>:</td><td> </td><td valign="top"><a href="#Shell-Parameters">Shell Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-parameters_002c-positional">parameters, positional</a>:</td><td> </td><td valign="top"><a href="#Positional-Parameters">Positional Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-parameters_002c-special">parameters, special</a>:</td><td> </td><td valign="top"><a href="#Special-Parameters">Special Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-pathname-expansion">pathname expansion</a>:</td><td> </td><td valign="top"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-pattern-matching">pattern matching</a>:</td><td> </td><td valign="top"><a href="#Pattern-Matching">Pattern Matching</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-pipeline">pipeline</a>:</td><td> </td><td valign="top"><a href="#Pipelines">Pipelines</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-POSIX">POSIX</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-POSIX-description">POSIX description</a>:</td><td> </td><td valign="top"><a href="#Bash-POSIX-Mode">Bash POSIX Mode</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-POSIX-Mode">POSIX Mode</a>:</td><td> </td><td valign="top"><a href="#Bash-POSIX-Mode">Bash POSIX Mode</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-process-group">process group</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-process-group-ID">process group ID</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-process-substitution">process substitution</a>:</td><td> </td><td valign="top"><a href="#Process-Substitution">Process Substitution</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-programmable-completion">programmable completion</a>:</td><td> </td><td valign="top"><a href="#Programmable-Completion">Programmable Completion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-prompting">prompting</a>:</td><td> </td><td valign="top"><a href="#Controlling-the-Prompt">Controlling the Prompt</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-Q">Q</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-quoting">quoting</a>:</td><td> </td><td valign="top"><a href="#Quoting">Quoting</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-quoting_002c-ANSI">quoting, ANSI</a>:</td><td> </td><td valign="top"><a href="#ANSI_002dC-Quoting">ANSI-C Quoting</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-R">R</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-Readline_002c-how-to-use">Readline, how to use</a>:</td><td> </td><td valign="top"><a href="#Job-Control-Variables">Job Control Variables</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-redirection">redirection</a>:</td><td> </td><td valign="top"><a href="#Redirections">Redirections</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-reserved-word">reserved word</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-reserved-words">reserved words</a>:</td><td> </td><td valign="top"><a href="#Reserved-Words">Reserved Words</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-restricted-shell">restricted shell</a>:</td><td> </td><td valign="top"><a href="#The-Restricted-Shell">The Restricted Shell</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-return-status">return status</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-S">S</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell-arithmetic">shell arithmetic</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell-function">shell function</a>:</td><td> </td><td valign="top"><a href="#Shell-Functions">Shell Functions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell-script">shell script</a>:</td><td> </td><td valign="top"><a href="#Shell-Scripts">Shell Scripts</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell-variable">shell variable</a>:</td><td> </td><td valign="top"><a href="#Shell-Parameters">Shell Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-shell_002c-interactive">shell, interactive</a>:</td><td> </td><td valign="top"><a href="#Interactive-Shells">Interactive Shells</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-signal">signal</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-signal-handling">signal handling</a>:</td><td> </td><td valign="top"><a href="#Signals">Signals</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-special-builtin">special builtin</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-special-builtin-1">special builtin</a>:</td><td> </td><td valign="top"><a href="#Special-Builtins">Special Builtins</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-startup-files">startup files</a>:</td><td> </td><td valign="top"><a href="#Bash-Startup-Files">Bash Startup Files</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-string-translations">string translations</a>:</td><td> </td><td valign="top"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-suspending-jobs">suspending jobs</a>:</td><td> </td><td valign="top"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-T">T</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-tilde-expansion">tilde expansion</a>:</td><td> </td><td valign="top"><a href="#Tilde-Expansion">Tilde Expansion</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-token">token</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-translation_002c-native-languages">translation, native languages</a>:</td><td> </td><td valign="top"><a href="#Locale-Translation">Locale Translation</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-U">U</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-unary-arithmetic-operators">unary arithmetic operators</a>:</td><td> </td><td valign="top"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-V">V</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-variable_002c-shell">variable, shell</a>:</td><td> </td><td valign="top"><a href="#Shell-Parameters">Shell Parameters</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-variables_002c-readline">variables, readline</a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-W">W</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-word">word</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-word-splitting">word splitting</a>:</td><td> </td><td valign="top"><a href="#Word-Splitting">Word Splitting</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
-<tr><th id="Concept-Index_cp_letter-Y">Y</th><td></td><td></td></tr>
-<tr><td></td><td
valign="top"><a href="#index-yanking-text">yanking text</a>:</td><td> </td><td valign="top"><a href="#Readline-Killing-Commands">Readline Killing Commands</a></td></tr>
-<tr><td colspan="4"> <hr></td></tr>
+<table class="cp-entries-printindex" border="0">
+<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-A">A</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-alias-expansion">alias expansion</a></td><td class="printindex-index-section"><a href="#Aliases">Aliases</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-arithmetic-evaluation">arithmetic evaluation</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-arithmetic-expansion">arithmetic expansion</a></td><td class="printindex-index-section"><a href="#Arithmetic-Expansion">Arithmetic Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-arithmetic-operators">arithmetic operators</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-arithmetic_002c-shell">arithmetic, shell</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-arrays">arrays</a></td><td class="printindex-index-section"><a href="#Arrays">Arrays</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-B">B</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-background">background</a></td><td class="printindex-index-section"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-Bash-configuration">Bash configuration</a></td><td class="printindex-index-section"><a href="#Basic-Installation">Basic Installation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-Bash-installation">Bash installation</a></td><td class="printindex-index-section"><a href="#Basic-Installation">Basic Installation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-binary-arithmetic-operators">binary arithmetic operators</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-bitwise-arithmetic-operators">bitwise arithmetic operators</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-Bourne-shell">Bourne shell</a></td><td class="printindex-index-section"><a href="#Basic-Shell-Features">Basic Shell Features</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-brace-expansion">brace expansion</a></td><td class="printindex-index-section"><a href="#Brace-Expansion">Brace Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-builtin-1">builtin</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-C">C</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-editing">command editing</a></td><td class="printindex-index-section"><a href="#Readline-Bare-Essentials">Readline Bare Essentials</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-execution">command execution</a></td><td class="printindex-index-section"><a href="#Command-Search-and-Execution">Command Search and Execution</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-expansion">command expansion</a></td><td class="printindex-index-section"><a href="#Simple-Command-Expansion">Simple Command Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-history">command history</a></td><td class="printindex-index-section"><a href="#Bash-History-Facilities">Bash History Facilities</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-search">command search</a></td><td class="printindex-index-section"><a href="#Command-Search-and-Execution">Command Search and Execution</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-substitution">command substitution</a></td><td class="printindex-index-section"><a href="#Command-Substitution">Command Substitution</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-command-timing">command timing</a></td><td class="printindex-index-section"><a href="#Pipelines">Pipelines</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-compound">commands, compound</a></td><td class="printindex-index-section"><a href="#Compound-Commands">Compound Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-conditional">commands, conditional</a></td><td class="printindex-index-section"><a href="#Conditional-Constructs">Conditional Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-grouping">commands, grouping</a></td><td class="printindex-index-section"><a href="#Command-Grouping">Command Grouping</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-lists">commands, lists</a></td><td class="printindex-index-section"><a href="#Lists">Lists</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-looping">commands, looping</a></td><td class="printindex-index-section"><a href="#Looping-Constructs">Looping Constructs</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-pipelines">commands, pipelines</a></td><td class="printindex-index-section"><a href="#Pipelines">Pipelines</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-shell">commands, shell</a></td><td class="printindex-index-section"><a href="#Shell-Commands">Shell Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-commands_002c-simple">commands, simple</a></td><td class="printindex-index-section"><a href="#Simple-Commands">Simple Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-comments_002c-shell">comments, shell</a></td><td class="printindex-index-section"><a href="#Comments">Comments</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-Compatibility-Level">Compatibility Level</a></td><td class="printindex-index-section"><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-Compatibility-Mode">Compatibility Mode</a></td><td class="printindex-index-section"><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-completion-builtins">completion builtins</a></td><td class="printindex-index-section"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-conditional-arithmetic-operator">conditional arithmetic operator</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-configuration">configuration</a></td><td class="printindex-index-section"><a href="#Basic-Installation">Basic Installation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-control-operator">control operator</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-coprocess">coprocess</a></td><td class="printindex-index-section"><a href="#Coprocesses">Coprocesses</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-D">D</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-directory-stack">directory stack</a></td><td class="printindex-index-section"><a href="#The-Directory-Stack">The Directory Stack</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-E">E</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-editing-command-lines">editing command lines</a></td><td class="printindex-index-section"><a href="#Readline-Bare-Essentials">Readline Bare Essentials</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-environment">environment</a></td><td class="printindex-index-section"><a href="#Environment">Environment</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-evaluation_002c-arithmetic">evaluation, arithmetic</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-event-designators">event designators</a></td><td class="printindex-index-section"><a href="#Event-Designators">Event Designators</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-execution-environment">execution environment</a></td><td class="printindex-index-section"><a href="#Command-Execution-Environment">Command Execution Environment</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-exit-status">exit status</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-exit-status-1">exit status</a></td><td class="printindex-index-section"><a href="#Exit-Status">Exit Status</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion">expansion</a></td><td class="printindex-index-section"><a href="#Shell-Expansions">Shell Expansions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion_002c-arithmetic">expansion, arithmetic</a></td><td class="printindex-index-section"><a href="#Arithmetic-Expansion">Arithmetic Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion_002c-brace">expansion, brace</a></td><td class="printindex-index-section"><a href="#Brace-Expansion">Brace Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion_002c-filename">expansion, filename</a></td><td class="printindex-index-section"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion_002c-parameter">expansion, parameter</a></td><td class="printindex-index-section"><a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion_002c-pathname">expansion, pathname</a></td><td class="printindex-index-section"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expansion_002c-tilde">expansion, tilde</a></td><td class="printindex-index-section"><a href="#Tilde-Expansion">Tilde Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expressions_002c-arithmetic">expressions, arithmetic</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-expressions_002c-conditional">expressions, conditional</a></td><td class="printindex-index-section"><a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-F">F</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-field">field</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-filename">filename</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-filename-expansion">filename expansion</a></td><td class="printindex-index-section"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-foreground">foreground</a></td><td class="printindex-index-section"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-functions_002c-shell">functions, shell</a></td><td class="printindex-index-section"><a href="#Shell-Functions">Shell Functions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-H">H</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history-builtins">history builtins</a></td><td class="printindex-index-section"><a href="#Bash-History-Builtins">Bash History Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history-events">history events</a></td><td class="printindex-index-section"><a href="#Event-Designators">Event Designators</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history-expansion">history expansion</a></td><td class="printindex-index-section"><a href="#History-Interaction">History Interaction</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-history-list">history list</a></td><td class="printindex-index-section"><a href="#Bash-History-Facilities">Bash History Facilities</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-History_002c-how-to-use">History, how to use</a></td><td class="printindex-index-section"><a href="#A-Programmable-Completion-Example">A Programmable Completion Example</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-I">I</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-identifier">identifier</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-initialization-file_002c-readline">initialization file, readline</a></td><td class="printindex-index-section"><a href="#Readline-Init-File">Readline Init File</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-installation">installation</a></td><td class="printindex-index-section"><a href="#Basic-Installation">Basic Installation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-interaction_002c-readline">interaction, readline</a></td><td class="printindex-index-section"><a href="#Readline-Interaction">Readline Interaction</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-interactive-shell">interactive shell</a></td><td class="printindex-index-section"><a href="#Invoking-Bash">Invoking Bash</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-interactive-shell-1">interactive shell</a></td><td class="printindex-index-section"><a href="#Interactive-Shells">Interactive Shells</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-internationalization">internationalization</a></td><td class="printindex-index-section"><a href="#Locale-Translation">Locale Translation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-internationalized-scripts">internationalized scripts</a></td><td class="printindex-index-section"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-J">J</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-job">job</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-job-control">job control</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-job-control-1">job control</a></td><td class="printindex-index-section"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-K">K</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-kill-ring">kill ring</a></td><td class="printindex-index-section"><a href="#Readline-Killing-Commands">Readline Killing Commands</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-killing-text">killing text</a></td><td class="printindex-index-section"><a href="#Readline-Killing-Commands">Readline Killing Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-L">L</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-localization">localization</a></td><td class="printindex-index-section"><a href="#Locale-Translation">Locale Translation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-login-shell">login shell</a></td><td class="printindex-index-section"><a href="#Invoking-Bash">Invoking Bash</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-M">M</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-matching_002c-pattern">matching, pattern</a></td><td class="printindex-index-section"><a href="#Pattern-Matching">Pattern Matching</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-metacharacter">metacharacter</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-N">N</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-name">name</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-native-languages">native languages</a></td><td class="printindex-index-section"><a href="#Locale-Translation">Locale Translation</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-notation_002c-readline">notation, readline</a></td><td class="printindex-index-section"><a href="#Readline-Bare-Essentials">Readline Bare Essentials</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-O">O</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-operator_002c-shell">operator, shell</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-P">P</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-parameter-expansion">parameter expansion</a></td><td class="printindex-index-section"><a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-parameters">parameters</a></td><td class="printindex-index-section"><a href="#Shell-Parameters">Shell Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-parameters_002c-positional">parameters, positional</a></td><td class="printindex-index-section"><a href="#Positional-Parameters">Positional Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-parameters_002c-special">parameters, special</a></td><td class="printindex-index-section"><a href="#Special-Parameters">Special Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-pathname-expansion">pathname expansion</a></td><td class="printindex-index-section"><a href="#Filename-Expansion">Filename Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-pattern-matching">pattern matching</a></td><td class="printindex-index-section"><a href="#Pattern-Matching">Pattern Matching</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-pipeline">pipeline</a></td><td class="printindex-index-section"><a href="#Pipelines">Pipelines</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-POSIX">POSIX</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-POSIX-description">POSIX description</a></td><td class="printindex-index-section"><a href="#Bash-POSIX-Mode">Bash POSIX Mode</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-POSIX-Mode">POSIX Mode</a></td><td class="printindex-index-section"><a href="#Bash-POSIX-Mode">Bash POSIX Mode</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-process-group">process group</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-process-group-ID">process group ID</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-process-substitution">process substitution</a></td><td class="printindex-index-section"><a href="#Process-Substitution">Process Substitution</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-programmable-completion">programmable completion</a></td><td class="printindex-index-section"><a href="#Programmable-Completion">Programmable Completion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-prompting">prompting</a></td><td class="printindex-index-section"><a href="#Controlling-the-Prompt">Controlling the Prompt</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-Q">Q</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-quoting">quoting</a></td><td class="printindex-index-section"><a href="#Quoting">Quoting</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-quoting_002c-ANSI">quoting, ANSI</a></td><td class="printindex-index-section"><a href="#ANSI_002dC-Quoting">ANSI-C Quoting</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-R">R</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-Readline_002c-how-to-use">Readline, how to use</a></td><td class="printindex-index-section"><a href="#Job-Control-Variables">Job Control Variables</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-redirection">redirection</a></td><td class="printindex-index-section"><a href="#Redirections">Redirections</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-reserved-word">reserved word</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-reserved-words">reserved words</a></td><td class="printindex-index-section"><a href="#Reserved-Words">Reserved Words</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-restricted-shell">restricted shell</a></td><td class="printindex-index-section"><a href="#The-Restricted-Shell">The Restricted Shell</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-return-status">return status</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-S">S</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell-arithmetic">shell arithmetic</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell-function">shell function</a></td><td class="printindex-index-section"><a href="#Shell-Functions">Shell Functions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell-script">shell script</a></td><td class="printindex-index-section"><a href="#Shell-Scripts">Shell Scripts</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell-variable">shell variable</a></td><td class="printindex-index-section"><a href="#Shell-Parameters">Shell Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-shell_002c-interactive">shell, interactive</a></td><td class="printindex-index-section"><a href="#Interactive-Shells">Interactive Shells</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-signal">signal</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-signal-handling">signal handling</a></td><td class="printindex-index-section"><a href="#Signals">Signals</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-special-builtin">special builtin</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-special-builtin-1">special builtin</a></td><td class="printindex-index-section"><a href="#Special-Builtins">Special Builtins</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-startup-files">startup files</a></td><td class="printindex-index-section"><a href="#Bash-Startup-Files">Bash Startup Files</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-string-translations">string translations</a></td><td class="printindex-index-section"><a href="#Creating-Internationalized-Scripts">Creating Internationalized Scripts</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-suspending-jobs">suspending jobs</a></td><td class="printindex-index-section"><a href="#Job-Control-Basics">Job Control Basics</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-T">T</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-tilde-expansion">tilde expansion</a></td><td class="printindex-index-section"><a href="#Tilde-Expansion">Tilde Expansion</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-token">token</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-translation_002c-native-languages">translation, native languages</a></td><td class="printindex-index-section"><a href="#Locale-Translation">Locale Translation</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-U">U</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-unary-arithmetic-operators">unary arithmetic operators</a></td><td class="printindex-index-section"><a href="#Shell-Arithmetic">Shell Arithmetic</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-V">V</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-variable_002c-shell">variable, shell</a></td><td class="printindex-index-section"><a href="#Shell-Parameters">Shell Parameters</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-variables_002c-readline">variables, readline</a></td><td class="printindex-index-section"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-W">W</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-word">word</a></td><td class="printindex-index-section"><a href="#Definitions">Definitions</a></td></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-word-splitting">word splitting</a></td><td class="printindex-index-section"><a href="#Word-Splitting">Word Splitting</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
+<tr><th id="Concept-Index_cp_letter-Y">Y</th></tr>
+<tr><td></td><td
class="printindex-index-entry"><a href="#index-yanking-text">yanking text</a></td><td class="printindex-index-section"><a href="#Readline-Killing-Commands">Readline Killing Commands</a></td></tr>
+<tr><td colspan="3"><hr></td></tr>
</table>
-<table><tr><th valign="top">Jump to: </th><td><a class="summary-letter" href="#Concept-Index_cp_letter-A"><b>A</b></a>
+<table class="cp-letters-footer-printindex"><tr><th>Jump to: </th><td><a class="summary-letter-printindex" href="#Concept-Index_cp_letter-A"><b>A</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-B"><b>B</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-B"><b>B</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-C"><b>C</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-C"><b>C</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-D"><b>D</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-D"><b>D</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-E"><b>E</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-E"><b>E</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-F"><b>F</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-F"><b>F</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-H"><b>H</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-H"><b>H</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-I"><b>I</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-I"><b>I</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-J"><b>J</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-J"><b>J</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-K"><b>K</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-K"><b>K</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-L"><b>L</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-L"><b>L</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-M"><b>M</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-M"><b>M</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-N"><b>N</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-N"><b>N</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-O"><b>O</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-O"><b>O</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-P"><b>P</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-P"><b>P</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-Q"><b>Q</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-Q"><b>Q</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-R"><b>R</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-R"><b>R</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-S"><b>S</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-S"><b>S</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-T"><b>T</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-T"><b>T</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-U"><b>U</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-U"><b>U</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-V"><b>V</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-V"><b>V</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-W"><b>W</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-W"><b>W</b></a>
-<a class="summary-letter" href="#Concept-Index_cp_letter-Y"><b>Y</b></a>
+<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-Y"><b>Y</b></a>
</td></tr></table>
+</div>
</div>
</div>
-This is bashref.info, produced by makeinfo version 6.8 from
+This is bashref.info, produced by makeinfo version 7.1 from
bashref.texi.
This text is a brief description of the features that are present in the
-Bash shell (version 5.3, 14 December 2023).
+Bash shell (version 5.3, 2 February 2024).
- This is Edition 5.3, last updated 14 December 2023, of 'The GNU Bash
-Reference Manual', for 'Bash', Version 5.3.
+ This is Edition 5.3, last updated 2 February 2024, of ‘The GNU Bash
+Reference Manual’, for ‘Bash’, Version 5.3.
- Copyright (C) 1988-2023 Free Software Foundation, Inc.
+ Copyright © 1988-2023 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
*************
This text is a brief description of the features that are present in the
-Bash shell (version 5.3, 14 December 2023). The Bash home page is
+Bash shell (version 5.3, 2 February 2024). The Bash home page is
<http://www.gnu.org/software/bash/>.
- This is Edition 5.3, last updated 14 December 2023, of 'The GNU Bash
-Reference Manual', for 'Bash', Version 5.3.
+ This is Edition 5.3, last updated 2 February 2024, of ‘The GNU Bash
+Reference Manual’, for ‘Bash’, Version 5.3.
Bash contains features that appear in other popular shells, and some
features that only appear in Bash. Some of the shells that Bash has
-borrowed concepts from are the Bourne Shell ('sh'), the Korn Shell
-('ksh'), and the C-shell ('csh' and its successor, 'tcsh'). The
+borrowed concepts from are the Bourne Shell (‘sh’), the Korn Shell
+(‘ksh’), and the C-shell (‘csh’ and its successor, ‘tcsh’). The
following menu breaks the features up into categories, noting which
features were inspired by other shells and which are specific to Bash.
=================
Bash is the shell, or command language interpreter, for the GNU
-operating system. The name is an acronym for the 'Bourne-Again SHell',
+operating system. The name is an acronym for the ‘Bourne-Again SHell’,
a pun on Stephen Bourne, the author of the direct ancestor of the
-current Unix shell 'sh', which appeared in the Seventh Edition Bell Labs
+current Unix shell ‘sh’, which appeared in the Seventh Edition Bell Labs
Research version of Unix.
- Bash is largely compatible with 'sh' and incorporates useful features
-from the Korn shell 'ksh' and the C shell 'csh'. It is intended to be a
+ Bash is largely compatible with ‘sh’ and incorporates useful features
+from the Korn shell ‘ksh’ and the C shell ‘csh’. It is intended to be a
conformant implementation of the IEEE POSIX Shell and Tools portion of
the IEEE POSIX specification (IEEE Standard 1003.1). It offers
-functional improvements over 'sh' for both interactive and programming
+functional improvements over ‘sh’ for both interactive and programming
use.
While the GNU operating system provides other shells, including a
-version of 'csh', Bash is the default shell. Like other GNU software,
+version of ‘csh’, Bash is the default shell. Like other GNU software,
Bash is quite portable. It currently runs on nearly every version of
-Unix and a few other operating systems - independently-supported ports
+Unix and a few other operating systems − independently-supported ports
exist for MS-DOS, OS/2, and Windows platforms.
\1f
features allow these utilities to be combined. Files containing
commands can be created, and become commands themselves. These new
commands have the same status as system commands in directories such as
-'/bin', allowing users or groups to establish custom environments to
+‘/bin’, allowing users or groups to establish custom environments to
automate their common tasks.
Shells may be used interactively or non-interactively. In
asynchronously. The shell waits for synchronous commands to complete
before accepting more input; asynchronous commands continue to execute
in parallel with the shell while it reads and executes additional
-commands. The "redirection" constructs permit fine-grained control of
+commands. The “redirection” constructs permit fine-grained control of
the input and output of those commands. Moreover, the shell allows
control over the contents of commands' environments.
- Shells also provide a small set of built-in commands ("builtins")
+ Shells also provide a small set of built-in commands (“builtins”)
implementing functionality impossible or inconvenient to obtain via
-separate utilities. For example, 'cd', 'break', 'continue', and 'exec'
+separate utilities. For example, ‘cd’, ‘break’, ‘continue’, and ‘exec’
cannot be implemented outside of the shell because they directly
-manipulate the shell itself. The 'history', 'getopts', 'kill', or 'pwd'
+manipulate the shell itself. The ‘history’, ‘getopts’, ‘kill’, or ‘pwd’
builtins, among others, could be implemented in separate utilities, but
they are more convenient to use as builtin commands. All of the shell
builtins are described in subsequent sections.
These definitions are used throughout the remainder of this manual.
-'POSIX'
+‘POSIX’
A family of open system standards based on Unix. Bash is primarily
concerned with the Shell and Utilities portion of the POSIX 1003.1
standard.
-'blank'
+‘blank’
A space or tab character.
-'builtin'
+‘builtin’
A command that is implemented internally by the shell itself,
rather than by an executable program somewhere in the file system.
-'control operator'
- A 'token' that performs a control function. It is a 'newline' or
- one of the following: '||', '&&', '&', ';', ';;', ';&', ';;&', '|',
- '|&', '(', or ')'.
+‘control operator’
+ A ‘token’ that performs a control function. It is a ‘newline’ or
+ one of the following: ‘||’, ‘&&’, ‘&’, ‘;’, ‘;;’, ‘;&’, ‘;;&’, ‘|’,
+ ‘|&’, ‘(’, or ‘)’.
-'exit status'
+‘exit status’
The value returned by a command to its caller. The value is
restricted to eight bits, so the maximum value is 255.
-'field'
+‘field’
A unit of text that is the result of one of the shell expansions.
After expansion, when executing a command, the resulting fields are
used as the command name and arguments.
-'filename'
+‘filename’
A string of characters used to identify a file.
-'job'
+‘job’
A set of processes comprising a pipeline, and any processes
descended from it, that are all in the same process group.
-'job control'
+‘job control’
A mechanism by which users can selectively stop (suspend) and
restart (resume) execution of processes.
-'metacharacter'
+‘metacharacter’
A character that, when unquoted, separates words. A metacharacter
- is a 'space', 'tab', 'newline', or one of the following characters:
- '|', '&', ';', '(', ')', '<', or '>'.
+ is a ‘space’, ‘tab’, ‘newline’, or one of the following characters:
+ ‘|’, ‘&’, ‘;’, ‘(’, ‘)’, ‘<’, or ‘>’.
-'name'
- A 'word' consisting solely of letters, numbers, and underscores,
- and beginning with a letter or underscore. 'Name's are used as
+‘name’
+ A ‘word’ consisting solely of letters, numbers, and underscores,
+ and beginning with a letter or underscore. ‘Name’s are used as
shell variable and function names. Also referred to as an
- 'identifier'.
+ ‘identifier’.
-'operator'
- A 'control operator' or a 'redirection operator'. *Note
+‘operator’
+ A ‘control operator’ or a ‘redirection operator’. *Note
Redirections::, for a list of redirection operators. Operators
- contain at least one unquoted 'metacharacter'.
+ contain at least one unquoted ‘metacharacter’.
-'process group'
+‘process group’
A collection of related processes each having the same process
group ID.
-'process group ID'
- A unique identifier that represents a 'process group' during its
+‘process group ID’
+ A unique identifier that represents a ‘process group’ during its
lifetime.
-'reserved word'
- A 'word' that has a special meaning to the shell. Most reserved
- words introduce shell flow control constructs, such as 'for' and
- 'while'.
+‘reserved word’
+ A ‘word’ that has a special meaning to the shell. Most reserved
+ words introduce shell flow control constructs, such as ‘for’ and
+ ‘while’.
-'return status'
- A synonym for 'exit status'.
+‘return status’
+ A synonym for ‘exit status’.
-'signal'
+‘signal’
A mechanism by which a process may be notified by the kernel of an
event occurring in the system.
-'special builtin'
+‘special builtin’
A shell builtin command that has been classified as special by the
POSIX standard.
-'token'
+‘token’
A sequence of characters considered a single unit by the shell. It
- is either a 'word' or an 'operator'.
+ is either a ‘word’ or an ‘operator’.
-'word'
+‘word’
A sequence of characters treated as a unit by the shell. Words may
- not include unquoted 'metacharacters'.
+ not include unquoted ‘metacharacters’.
\1f
File: bashref.info, Node: Basic Shell Features, Next: Shell Builtin Commands, Prev: Definitions, Up: Top
3 Basic Shell Features
**********************
-Bash is an acronym for 'Bourne-Again SHell'. The Bourne shell is the
+Bash is an acronym for ‘Bourne-Again SHell’. The Bourne shell is the
traditional Unix shell originally written by Stephen Bourne. All of the
Bourne shell builtin commands are available in Bash, The rules for
evaluation and quoting are taken from the POSIX specification for the
When the shell reads input, it proceeds through a sequence of
operations. If the input indicates the beginning of a comment, the
-shell ignores the comment symbol ('#'), and the rest of that line.
+shell ignores the comment symbol (‘#’), and the rest of that line.
Otherwise, roughly speaking, the shell reads its input and divides
the input into words and operators, employing the quoting rules to
reads and executes a command. Basically, the shell does the following:
1. Reads its input from a file (*note Shell Scripts::), from a string
- supplied as an argument to the '-c' invocation option (*note
+ supplied as an argument to the ‘-c’ invocation option (*note
Invoking Bash::), or from the user's terminal.
2. Breaks the input into words and operators, obeying the quoting
rules described in *note Quoting::. These tokens are separated by
- 'metacharacters'. Alias expansion is performed by this step (*note
+ ‘metacharacters’. Alias expansion is performed by this step (*note
Aliases::).
3. Parses the tokens into simple and compound commands (*note Shell
Each of the shell metacharacters (*note Definitions::) has special
meaning to the shell and must be quoted if it is to represent itself.
When the command history expansion facilities are being used (*note
-History Interaction::), the "history expansion" character, usually '!',
+History Interaction::), the “history expansion” character, usually ‘!’,
must be quoted to prevent history expansion. *Note Bash History
Facilities::, for more details concerning history expansion.
- There are three quoting mechanisms: the "escape character", single
+ There are three quoting mechanisms: the “escape character”, single
quotes, and double quotes.
\1f
3.1.2.1 Escape Character
........................
-A non-quoted backslash '\' is the Bash escape character. It preserves
+A non-quoted backslash ‘\’ is the Bash escape character. It preserves
the literal value of the next character that follows, with the exception
-of 'newline'. If a '\newline' pair appears, and the backslash itself is
-not quoted, the '\newline' is treated as a line continuation (that is,
+of ‘newline’. If a ‘\newline’ pair appears, and the backslash itself is
+not quoted, the ‘\newline’ is treated as a line continuation (that is,
it is removed from the input stream and effectively ignored).
\1f
3.1.2.2 Single Quotes
.....................
-Enclosing characters in single quotes (''') preserves the literal value
+Enclosing characters in single quotes (‘'’) preserves the literal value
of each character within the quotes. A single quote may not occur
between single quotes, even when preceded by a backslash.
3.1.2.3 Double Quotes
.....................
-Enclosing characters in double quotes ('"') preserves the literal value
-of all characters within the quotes, with the exception of '$', '`',
-'\', and, when history expansion is enabled, '!'. When the shell is in
-POSIX mode (*note Bash POSIX Mode::), the '!' has no special meaning
+Enclosing characters in double quotes (‘"’) preserves the literal value
+of all characters within the quotes, with the exception of ‘$’, ‘`’,
+‘\’, and, when history expansion is enabled, ‘!’. When the shell is in
+POSIX mode (*note Bash POSIX Mode::), the ‘!’ has no special meaning
within double quotes, even when history expansion is enabled. The
-characters '$' and '`' retain their special meaning within double quotes
+characters ‘$’ and ‘`’ retain their special meaning within double quotes
(*note Shell Expansions::). The backslash retains its special meaning
-only when followed by one of the following characters: '$', '`', '"',
-'\', or 'newline'. Within double quotes, backslashes that are followed
+only when followed by one of the following characters: ‘$’, ‘`’, ‘"’,
+‘\’, or ‘newline’. Within double quotes, backslashes that are followed
by one of these characters are removed. Backslashes preceding
characters without a special meaning are left unmodified. A double
quote may be quoted within double quotes by preceding it with a
backslash. If enabled, history expansion will be performed unless an
-'!' appearing in double quotes is escaped using a backslash. The
-backslash preceding the '!' is not removed.
+‘!’ appearing in double quotes is escaped using a backslash. The
+backslash preceding the ‘!’ is not removed.
- The special parameters '*' and '@' have special meaning when in
+ The special parameters ‘*’ and ‘@’ have special meaning when in
double quotes (*note Shell Parameter Expansion::).
\1f
3.1.2.4 ANSI-C Quoting
......................
-Character sequences of the form '$'STRING'' are treated as a special
+Character sequences of the form ‘$'STRING'’ are treated as a special
kind of single quotes. The sequence expands to STRING, with
backslash-escaped characters in STRING replaced as specified by the ANSI
C standard. Backslash escape sequences, if present, are decoded as
follows:
-'\a'
+‘\a’
alert (bell)
-'\b'
+‘\b’
backspace
-'\e'
-'\E'
+‘\e’
+‘\E’
an escape character (not ANSI C)
-'\f'
+‘\f’
form feed
-'\n'
+‘\n’
newline
-'\r'
+‘\r’
carriage return
-'\t'
+‘\t’
horizontal tab
-'\v'
+‘\v’
vertical tab
-'\\'
+‘\\’
backslash
-'\''
+‘\'’
single quote
-'\"'
+‘\"’
double quote
-'\?'
+‘\?’
question mark
-'\NNN'
+‘\NNN’
the eight-bit character whose value is the octal value NNN (one to
three octal digits)
-'\xHH'
+‘\xHH’
the eight-bit character whose value is the hexadecimal value HH
(one or two hex digits)
-'\uHHHH'
+‘\uHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHH (one to four hex digits)
-'\UHHHHHHHH'
+‘\UHHHHHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHHHHHH (one to eight hex digits)
-'\cX'
+‘\cX’
a control-X character
The expanded result is single-quoted, as if the dollar sign had not been
* Creating Internationalized Scripts:: How to use translations and different
languages in your scripts.
-Prefixing a double-quoted string with a dollar sign ('$'), such as
+Prefixing a double-quoted string with a dollar sign (‘$’), such as
$"hello, world", will cause the string to be translated according to the
-current locale. The 'gettext' infrastructure performs the lookup and
-translation, using the 'LC_MESSAGES', 'TEXTDOMAINDIR', and 'TEXTDOMAIN'
+current locale. The ‘gettext’ infrastructure performs the lookup and
+translation, using the ‘LC_MESSAGES’, ‘TEXTDOMAINDIR’, and ‘TEXTDOMAIN’
shell variables, as explained below. See the gettext documentation for
-additional details not covered here. If the current locale is 'C' or
-'POSIX', if there are no translations available, of if the string is not
+additional details not covered here. If the current locale is ‘C’ or
+‘POSIX’, if there are no translations available, of if the string is not
translated, the dollar sign is ignored. Since this is a form of double
quoting, the string remains double-quoted by default, whether or not it
-is translated and replaced. If the 'noexpand_translation' option is
-enabled using the 'shopt' builtin (*note The Shopt Builtin::),
+is translated and replaced. If the ‘noexpand_translation’ option is
+enabled using the ‘shopt’ builtin (*note The Shopt Builtin::),
translated strings are single-quoted instead of double-quoted.
The rest of this section is a brief overview of how you use gettext
bash --dump-po-strings SCRIPTNAME > DOMAIN.pot
-The DOMAIN is your "message domain". It's just an arbitrary string
+The DOMAIN is your “message domain”. It's just an arbitrary string
that's used to identify the files gettext needs, like a package or
script name. It needs to be unique among all the message domains on
systems where you install the translations, so gettext knows which
translations correspond to your script. You'll use the template file to
create translations for each target language. The template file
-conventionally has the suffix '.pot'.
+conventionally has the suffix ‘.pot’.
You copy this template file to a separate file for each target
language you want to support (called "PO" files, which use the suffix
-'.po'). PO files use various naming conventions, but when you are
+‘.po’). PO files use various naming conventions, but when you are
working to translate a template file into a particular language, you
first copy the template file to a file whose name is the language you
-want to target, with the '.po' suffix. For instance, the Spanish
-translations of your strings would be in a file named 'es.po', and to
+want to target, with the ‘.po’ suffix. For instance, the Spanish
+translations of your strings would be in a file named ‘es.po’, and to
get started using a message domain named "example," you would run
cp example.pot es.po
gettext tools to produce what are called "MO" files, which are compiled
versions of the PO files the gettext tools use to look up translations
efficiently. MO files are also called "message catalog" files. You use
-the 'msgfmt' program to do this. For instance, if you had a file with
+the ‘msgfmt’ program to do this. For instance, if you had a file with
Spanish translations, you could run
msgfmt -o es.mo es.po
to produce the corresponding MO file.
Once you have the MO files, you decide where to install them and use
-the 'TEXTDOMAINDIR' shell variable to tell the gettext tools where they
+the ‘TEXTDOMAINDIR’ shell variable to tell the gettext tools where they
are. Make sure to use the same message domain to name the MO files as
you did for the PO files when you install them.
- Your users will use the 'LANG' or 'LC_MESSAGES' shell variables to
+ Your users will use the ‘LANG’ or ‘LC_MESSAGES’ shell variables to
select the desired language.
- You set the 'TEXTDOMAIN' variable to the script's message domain. As
+ You set the ‘TEXTDOMAIN’ variable to the script's message domain. As
above, you use the message domain to name your translation files.
- You, or possibly your users, set the 'TEXTDOMAINDIR' variable to the
+ You, or possibly your users, set the ‘TEXTDOMAINDIR’ variable to the
name of a directory where the message catalog files are stored. If you
install the message files into the system's standard message catalog
directory, you don't need to worry about this variable.
The directory where the message catalog files are stored varies
between systems. Some use the message catalog selected by the
-'LC_MESSAGES' shell variable. Others create the name of the message
-catalog from the value of the 'TEXTDOMAIN' shell variable, possibly
-adding the '.mo' suffix. If you use the 'TEXTDOMAIN' variable, you may
-need to set the 'TEXTDOMAINDIR' variable to the location of the message
+‘LC_MESSAGES’ shell variable. Others create the name of the message
+catalog from the value of the ‘TEXTDOMAIN’ shell variable, possibly
+adding the ‘.mo’ suffix. If you use the ‘TEXTDOMAIN’ variable, you may
+need to set the ‘TEXTDOMAINDIR’ variable to the location of the message
catalog files, as above. It's common to use both variables in this
-fashion: '$TEXTDOMAINDIR'/'$LC_MESSAGES'/LC_MESSAGES/'$TEXTDOMAIN'.mo.
+fashion: ‘$TEXTDOMAINDIR’/‘$LC_MESSAGES’/LC_MESSAGES/‘$TEXTDOMAIN’.mo.
If you used that last convention, and you wanted to store the message
catalog files with Spanish (es) and Esperanto (eo) translations into a
When all of this is done, and the message catalog files containing
the compiled translations are installed in the correct location, your
users will be able to see translated strings in any of the supported
-languages by setting the 'LANG' or 'LC_MESSAGES' environment variables
+languages by setting the ‘LANG’ or ‘LC_MESSAGES’ environment variables
before running your script.
\1f
--------------
In a non-interactive shell, or an interactive shell in which the
-'interactive_comments' option to the 'shopt' builtin is enabled (*note
-The Shopt Builtin::), a word beginning with '#' causes that word and all
+‘interactive_comments’ option to the ‘shopt’ builtin is enabled (*note
+The Shopt Builtin::), a word beginning with ‘#’ causes that word and all
remaining characters on that line to be ignored. An interactive shell
-without the 'interactive_comments' option enabled does not allow
-comments. The 'interactive_comments' option is on by default in
+without the ‘interactive_comments’ option enabled does not allow
+comments. The ‘interactive_comments’ option is on by default in
interactive shells. *Note Interactive Shells::, for a description of
what makes a shell interactive.
3.2 Shell Commands
==================
-A simple shell command such as 'echo a b c' consists of the command
+A simple shell command such as ‘echo a b c’ consists of the command
itself followed by arguments, separated by spaces.
More complex shell commands are composed of simple commands arranged
The following words are recognized as reserved when unquoted and the
first word of a command (see below for exceptions):
-'if' 'then' 'elif' 'else' 'fi' 'time'
-'for' 'in' 'until' 'while' 'do' 'done'
-'case' 'esac' 'coproc''select''function'
-'{' '}' '[[' ']]' '!'
+‘if’ ‘then’ ‘elif’ ‘else’ ‘fi’ ‘time’
+‘for’ ‘in’ ‘until’ ‘while’ ‘do’ ‘done’
+‘case’ ‘esac’ ‘coproc’‘select’‘function’
+‘{’ ‘}’ ‘[[’ ‘]]’ ‘!’
-'in' is recognized as a reserved word if it is the third word of a
-'case' or 'select' command. 'in' and 'do' are recognized as reserved
-words if they are the third word in a 'for' command.
+‘in’ is recognized as a reserved word if it is the third word of a
+‘case’ or ‘select’ command. ‘in’ and ‘do’ are recognized as reserved
+words if they are the third word in a ‘for’ command.
\1f
File: bashref.info, Node: Simple Commands, Next: Pipelines, Prev: Reserved Words, Up: Shell Commands
---------------------
A simple command is the kind of command encountered most often. It's
-just a sequence of words separated by 'blank's, terminated by one of the
+just a sequence of words separated by ‘blank’s, terminated by one of the
shell's control operators (*note Definitions::). The first word
generally specifies a command to be executed, with the rest of the words
being that command's arguments.
The return status (*note Exit Status::) of a simple command is its
-exit status as provided by the POSIX 1003.1 'waitpid' function, or 128+N
+exit status as provided by the POSIX 1003.1 ‘waitpid’ function, or 128+N
if the command was terminated by signal N.
\1f
3.2.3 Pipelines
---------------
-A 'pipeline' is a sequence of one or more commands separated by one of
-the control operators '|' or '|&'.
+A ‘pipeline’ is a sequence of one or more commands separated by one of
+the control operators ‘|’ or ‘|&’.
The format for a pipeline is
[time [-p]] [!] COMMAND1 [ | or |& COMMAND2 ] ...
command's output. This connection is performed before any redirections
specified by COMMAND1.
- If '|&' is used, COMMAND1's standard error, in addition to its
+ If ‘|&’ is used, COMMAND1's standard error, in addition to its
standard output, is connected to COMMAND2's standard input through the
-pipe; it is shorthand for '2>&1 |'. This implicit redirection of the
+pipe; it is shorthand for ‘2>&1 |’. This implicit redirection of the
standard error to the standard output is performed after any
redirections specified by COMMAND1.
- The reserved word 'time' causes timing statistics to be printed for
+ The reserved word ‘time’ causes timing statistics to be printed for
the pipeline once it finishes. The statistics currently consist of
elapsed (wall-clock) time and user and system time consumed by the
-command's execution. The '-p' option changes the output format to that
+command's execution. The ‘-p’ option changes the output format to that
specified by POSIX. When the shell is in POSIX mode (*note Bash POSIX
-Mode::), it does not recognize 'time' as a reserved word if the next
-token begins with a '-'. The 'TIMEFORMAT' variable may be set to a
+Mode::), it does not recognize ‘time’ as a reserved word if the next
+token begins with a ‘-’. The ‘TIMEFORMAT’ variable may be set to a
format string that specifies how the timing information should be
displayed. *Note Bash Variables::, for a description of the available
-formats. The use of 'time' as a reserved word permits the timing of
-shell builtins, shell functions, and pipelines. An external 'time'
+formats. The use of ‘time’ as a reserved word permits the timing of
+shell builtins, shell functions, and pipelines. An external ‘time’
command cannot time these easily.
- When the shell is in POSIX mode (*note Bash POSIX Mode::), 'time' may
+ When the shell is in POSIX mode (*note Bash POSIX Mode::), ‘time’ may
be followed by a newline. In this case, the shell displays the total
user and system time consumed by the shell and its children. The
-'TIMEFORMAT' variable specifies the format of the time information.
+‘TIMEFORMAT’ variable specifies the format of the time information.
If the pipeline is not executed asynchronously (*note Lists::), the
shell waits for all commands in the pipeline to complete.
Each command in a multi-command pipeline, where pipes are created, is
-executed in its own "subshell", which is a separate process (*note
-Command Execution Environment::). If the 'lastpipe' option is enabled
-using the 'shopt' builtin (*note The Shopt Builtin::), the last element
+executed in its own “subshell”, which is a separate process (*note
+Command Execution Environment::). If the ‘lastpipe’ option is enabled
+using the ‘shopt’ builtin (*note The Shopt Builtin::), the last element
of a pipeline may be run by the shell process when job control is not
active.
The exit status of a pipeline is the exit status of the last command
-in the pipeline, unless the 'pipefail' option is enabled (*note The Set
-Builtin::). If 'pipefail' is enabled, the pipeline's return status is
+in the pipeline, unless the ‘pipefail’ option is enabled (*note The Set
+Builtin::). If ‘pipefail’ is enabled, the pipeline's return status is
the value of the last (rightmost) command to exit with a non-zero
status, or zero if all commands exit successfully. If the reserved word
-'!' precedes the pipeline, the exit status is the logical negation of
+‘!’ precedes the pipeline, the exit status is the logical negation of
the exit status as described above. The shell waits for all commands in
the pipeline to terminate before returning a value.
3.2.4 Lists of Commands
-----------------------
-A 'list' is a sequence of one or more pipelines separated by one of the
-operators ';', '&', '&&', or '||', and optionally terminated by one of
-';', '&', or a 'newline'.
+A ‘list’ is a sequence of one or more pipelines separated by one of the
+operators ‘;’, ‘&’, ‘&&’, or ‘||’, and optionally terminated by one of
+‘;’, ‘&’, or a ‘newline’.
- Of these list operators, '&&' and '||' have equal precedence,
-followed by ';' and '&', which have equal precedence.
+ Of these list operators, ‘&&’ and ‘||’ have equal precedence,
+followed by ‘;’ and ‘&’, which have equal precedence.
- A sequence of one or more newlines may appear in a 'list' to delimit
+ A sequence of one or more newlines may appear in a ‘list’ to delimit
commands, equivalent to a semicolon.
- If a command is terminated by the control operator '&', the shell
+ If a command is terminated by the control operator ‘&’, the shell
executes the command asynchronously in a subshell. This is known as
-executing the command in the "background", and these are referred to as
-"asynchronous" commands. The shell does not wait for the command to
+executing the command in the “background”, and these are referred to as
+“asynchronous” commands. The shell does not wait for the command to
finish, and the return status is 0 (true). When job control is not
active (*note Job Control::), the standard input for asynchronous
commands, in the absence of any explicit redirections, is redirected
-from '/dev/null'.
+from ‘/dev/null’.
- Commands separated by a ';' are executed sequentially; the shell
+ Commands separated by a ‘;’ are executed sequentially; the shell
waits for each command to terminate in turn. The return status is the
exit status of the last command executed.
AND and OR lists are sequences of one or more pipelines separated by
-the control operators '&&' and '||', respectively. AND and OR lists are
+the control operators ‘&&’ and ‘||’, respectively. AND and OR lists are
executed with left associativity.
An AND list has the form
Bash supports the following looping constructs.
- Note that wherever a ';' appears in the description of a command's
+ Note that wherever a ‘;’ appears in the description of a command's
syntax, it may be replaced with one or more newlines.
-'until'
- The syntax of the 'until' command is:
+‘until’
+ The syntax of the ‘until’ command is:
until TEST-COMMANDS; do CONSEQUENT-COMMANDS; done
the last command executed in CONSEQUENT-COMMANDS, or zero if none
was executed.
-'while'
- The syntax of the 'while' command is:
+‘while’
+ The syntax of the ‘while’ command is:
while TEST-COMMANDS; do CONSEQUENT-COMMANDS; done
command executed in CONSEQUENT-COMMANDS, or zero if none was
executed.
-'for'
- The syntax of the 'for' command is:
+‘for’
+ The syntax of the ‘for’ command is:
for NAME [ [in [WORDS ...] ] ; ] do COMMANDS; done
Expand WORDS (*note Shell Expansions::), and execute COMMANDS once
for each member in the resultant list, with NAME bound to the
- current member. If 'in WORDS' is not present, the 'for' command
+ current member. If ‘in WORDS’ is not present, the ‘for’ command
executes the COMMANDS once for each positional parameter that is
- set, as if 'in "$@"' had been specified (*note Special
+ set, as if ‘in "$@"’ had been specified (*note Special
Parameters::).
The return status is the exit status of the last command that
executes. If there are no items in the expansion of WORDS, no
commands are executed, and the return status is zero.
- An alternate form of the 'for' command is also supported:
+ An alternate form of the ‘for’ command is also supported:
for (( EXPR1 ; EXPR2 ; EXPR3 )) ; do COMMANDS ; done
command in COMMANDS that is executed, or false if any of the
expressions is invalid.
- The 'break' and 'continue' builtins (*note Bourne Shell Builtins::)
+ The ‘break’ and ‘continue’ builtins (*note Bourne Shell Builtins::)
may be used to control loop execution.
\1f
3.2.5.2 Conditional Constructs
..............................
-'if'
- The syntax of the 'if' command is:
+‘if’
+ The syntax of the ‘if’ command is:
if TEST-COMMANDS; then
CONSEQUENT-COMMANDS;
The TEST-COMMANDS list is executed, and if its return status is
zero, the CONSEQUENT-COMMANDS list is executed. If TEST-COMMANDS
- returns a non-zero status, each 'elif' list is executed in turn,
+ returns a non-zero status, each ‘elif’ list is executed in turn,
and if its exit status is zero, the corresponding MORE-CONSEQUENTS
- is executed and the command completes. If 'else
- ALTERNATE-CONSEQUENTS' is present, and the final command in the
- final 'if' or 'elif' clause has a non-zero exit status, then
+ is executed and the command completes. If ‘else
+ ALTERNATE-CONSEQUENTS’ is present, and the final command in the
+ final ‘if’ or ‘elif’ clause has a non-zero exit status, then
ALTERNATE-CONSEQUENTS is executed. The return status is the exit
status of the last command executed, or zero if no condition tested
true.
-'case'
- The syntax of the 'case' command is:
+‘case’
+ The syntax of the ‘case’ command is:
case WORD in
[ [(] PATTERN [| PATTERN]...) COMMAND-LIST ;;]...
esac
- 'case' will selectively execute the COMMAND-LIST corresponding to
+ ‘case’ will selectively execute the COMMAND-LIST corresponding to
the first PATTERN that matches WORD. The match is performed
according to the rules described below in *note Pattern Matching::.
- If the 'nocasematch' shell option (see the description of 'shopt'
+ If the ‘nocasematch’ shell option (see the description of ‘shopt’
in *note The Shopt Builtin::) is enabled, the match is performed
- without regard to the case of alphabetic characters. The '|' is
- used to separate multiple patterns, and the ')' operator terminates
+ without regard to the case of alphabetic characters. The ‘|’ is
+ used to separate multiple patterns, and the ‘)’ operator terminates
a pattern list. A list of patterns and an associated command-list
is known as a CLAUSE.
- Each clause must be terminated with ';;', ';&', or ';;&'. The WORD
+ Each clause must be terminated with ‘;;’, ‘;&’, or ‘;;&’. The WORD
undergoes tilde expansion, parameter expansion, command
substitution, arithmetic expansion, and quote removal (*note Shell
Parameter Expansion::) before matching is attempted. Each PATTERN
substitution, arithmetic expansion, process substitution, and quote
removal.
- There may be an arbitrary number of 'case' clauses, each terminated
- by a ';;', ';&', or ';;&'. The first pattern that matches
+ There may be an arbitrary number of ‘case’ clauses, each terminated
+ by a ‘;;’, ‘;&’, or ‘;;&’. The first pattern that matches
determines the command-list that is executed. It's a common idiom
- to use '*' as the final pattern to define the default case, since
+ to use ‘*’ as the final pattern to define the default case, since
that pattern will always match.
- Here is an example using 'case' in a script that could be used to
+ Here is an example using ‘case’ in a script that could be used to
describe one interesting feature of an animal:
echo -n "Enter the name of an animal: "
esac
echo " legs."
-
- If the ';;' operator is used, no subsequent matches are attempted
- after the first pattern match. Using ';&' in place of ';;' causes
+ If the ‘;;’ operator is used, no subsequent matches are attempted
+ after the first pattern match. Using ‘;&’ in place of ‘;;’ causes
execution to continue with the COMMAND-LIST associated with the
- next clause, if any. Using ';;&' in place of ';;' causes the shell
+ next clause, if any. Using ‘;;&’ in place of ‘;;’ causes the shell
to test the patterns in the next clause, if any, and execute any
associated COMMAND-LIST on a successful match, continuing the case
statement execution as if the pattern list had not matched.
The return status is zero if no PATTERN is matched. Otherwise, the
return status is the exit status of the COMMAND-LIST executed.
-'select'
+‘select’
- The 'select' construct allows the easy generation of menus. It has
- almost the same syntax as the 'for' command:
+ The ‘select’ construct allows the easy generation of menus. It has
+ almost the same syntax as the ‘for’ command:
select NAME [in WORDS ...]; do COMMANDS; done
- The list of words following 'in' is expanded, generating a list of
+ The list of words following ‘in’ is expanded, generating a list of
items, and the set of expanded words is printed on the standard
- error output stream, each preceded by a number. If the 'in WORDS'
- is omitted, the positional parameters are printed, as if 'in "$@"'
- had been specified. 'select' then displays the 'PS3' prompt and
+ error output stream, each preceded by a number. If the ‘in WORDS’
+ is omitted, the positional parameters are printed, as if ‘in "$@"’
+ had been specified. ‘select’ then displays the ‘PS3’ prompt and
reads a line from the standard input. If the line consists of a
number corresponding to one of the displayed words, then the value
of NAME is set to that word. If the line is empty, the words and
- prompt are displayed again. If 'EOF' is read, the 'select' command
+ prompt are displayed again. If ‘EOF’ is read, the ‘select’ command
completes and returns 1. Any other value read causes NAME to be
- set to null. The line read is saved in the variable 'REPLY'.
+ set to null. The line read is saved in the variable ‘REPLY’.
- The COMMANDS are executed after each selection until a 'break'
- command is executed, at which point the 'select' command completes.
+ The COMMANDS are executed after each selection until a ‘break’
+ command is executed, at which point the ‘select’ command completes.
Here is an example that allows the user to pick a filename from the
current directory, and displays the name and index of the file
break;
done
-'((...))'
+‘((...))’
(( EXPRESSION ))
The arithmetic EXPRESSION is evaluated according to the rules
are removed. If the value of the expression is non-zero, the
return status is 0; otherwise the return status is 1.
-'[[...]]'
+‘[[...]]’
[[ EXPRESSION ]]
Return a status of 0 or 1 depending on the evaluation of the
conditional expression EXPRESSION. Expressions are composed of the
primaries described below in *note Bash Conditional Expressions::.
- The words between the '[[' and ']]' do not undergo word splitting
+ The words between the ‘[[’ and ‘]]’ do not undergo word splitting
and filename expansion. The shell performs tilde expansion,
parameter and variable expansion, arithmetic expansion, command
substitution, process substitution, and quote removal on those
words (the expansions that would occur if the words were enclosed
- in double quotes). Conditional operators such as '-f' must be
+ in double quotes). Conditional operators such as ‘-f’ must be
unquoted to be recognized as primaries.
- When used with '[[', the '<' and '>' operators sort
+ When used with ‘[[’, the ‘<’ and ‘>’ operators sort
lexicographically using the current locale.
- When the '==' and '!=' operators are used, the string to the right
+ When the ‘==’ and ‘!=’ operators are used, the string to the right
of the operator is considered a pattern and matched according to
the rules described below in *note Pattern Matching::, as if the
- 'extglob' shell option were enabled. The '=' operator is identical
- to '=='. If the 'nocasematch' shell option (see the description of
- 'shopt' in *note The Shopt Builtin::) is enabled, the match is
+ ‘extglob’ shell option were enabled. The ‘=’ operator is identical
+ to ‘==’. If the ‘nocasematch’ shell option (see the description of
+ ‘shopt’ in *note The Shopt Builtin::) is enabled, the match is
performed without regard to the case of alphabetic characters. The
- return value is 0 if the string matches ('==') or does not match
- ('!=') the pattern, and 1 otherwise.
+ return value is 0 if the string matches (‘==’) or does not match
+ (‘!=’) the pattern, and 1 otherwise.
If you quote any part of the pattern, using any of the shell's
quoting mechanisms, the quoted portion is matched literally. This
means every character in the quoted portion matches itself, instead
of having any special pattern matching meaning.
- An additional binary operator, '=~', is available, with the same
- precedence as '==' and '!='. When you use '=~', the string to the
+ An additional binary operator, ‘=~’, is available, with the same
+ precedence as ‘==’ and ‘!=’. When you use ‘=~’, the string to the
right of the operator is considered a POSIX extended regular
expression pattern and matched accordingly (using the POSIX
- 'regcomp' and 'regexec' interfaces usually described in regex(3)).
+ ‘regcomp’ and ‘regexec’ interfaces usually described in regex(3)).
The return value is 0 if the string matches the pattern, and 1 if
it does not. If the regular expression is syntactically incorrect,
- the conditional expression returns 2. If the 'nocasematch' shell
- option (see the description of 'shopt' in *note The Shopt
+ the conditional expression returns 2. If the ‘nocasematch’ shell
+ option (see the description of ‘shopt’ in *note The Shopt
Builtin::) is enabled, the match is performed without regard to the
case of alphabetic characters.
The pattern will match if it matches any part of the string. If
you want to force the pattern to match the entire string, anchor
- the pattern using the '^' and '$' regular expression operators.
+ the pattern using the ‘^’ and ‘$’ regular expression operators.
For example, the following will match a line (stored in the shell
- variable 'line') if there is a sequence of characters anywhere in
+ variable ‘line’) if there is a sequence of characters anywhere in
the value consisting of any number, including zero, of characters
- in the 'space' character class, immediately followed by zero or one
- instances of 'a', then a 'b':
+ in the ‘space’ character class, immediately followed by zero or one
+ instances of ‘a’, then a ‘b’:
[[ $line =~ [[:space:]]*(a)?b ]]
- That means values for 'line' like 'aab', ' aaaaaab', 'xaby', and '
- ab' will all match, as will a line containing a 'b' anywhere in its
+ That means values for ‘line’ like ‘aab’, ‘ aaaaaab’, ‘xaby’, and ‘
+ ab’ will all match, as will a line containing a ‘b’ anywhere in its
value.
If you want to match a character that's special to the regular
- expression grammar ('^$|[]()\.*+?'), it has to be quoted to remove
- its special meaning. This means that in the pattern 'xxx.txt', the
- '.' matches any character in the string (its usual regular
- expression meaning), but in the pattern '"xxx.txt"', it can only
- match a literal '.'.
+ expression grammar (‘^$|[]()\.*+?’), it has to be quoted to remove
+ its special meaning. This means that in the pattern ‘xxx.txt’, the
+ ‘.’ matches any character in the string (its usual regular
+ expression meaning), but in the pattern ‘"xxx.txt"’, it can only
+ match a literal ‘.’.
Likewise, if you want to include a character in your pattern that
has a special meaning to the regular expression grammar, you must
make sure it's not quoted. If you want to anchor a pattern at the
beginning or end of the string, for instance, you cannot quote the
- '^' or '$' characters using any form of shell quoting.
+ ‘^’ or ‘$’ characters using any form of shell quoting.
- If you want to match 'initial string' at the start of a line, the
+ If you want to match ‘initial string’ at the start of a line, the
following will work:
[[ $line =~ ^"initial string" ]]
but this will not:
[[ $line =~ "^initial string" ]]
- because in the second example the '^' is quoted and doesn't have
+ because in the second example the ‘^’ is quoted and doesn't have
its usual special meaning.
It is sometimes difficult to specify a regular expression properly
The first two matches will succeed, but the second two will not,
because in the second two the backslash will be part of the pattern
to be matched. In the first two examples, the pattern passed to
- the regular expression parser is '\.'. The backslash removes the
- special meaning from '.', so the literal '.' matches. In the
+ the regular expression parser is ‘\.’. The backslash removes the
+ special meaning from ‘.’, so the literal ‘.’ matches. In the
second two examples, the pattern passed to the regular expression
- parser has the backslash quoted (e.g., '\\\.'), which will not
+ parser has the backslash quoted (e.g., ‘\\\.’), which will not
match the string, since it does not contain a backslash. If the
- string in the first examples were anything other than '.', say 'a',
- the pattern would not match, because the quoted '.' in the pattern
+ string in the first examples were anything other than ‘.’, say ‘a’,
+ the pattern would not match, because the quoted ‘.’ in the pattern
loses its special meaning of matching any single character.
Bracket expressions in regular expressions can be sources of errors
purpose.
Though it might seem like a strange way to write it, the following
- pattern will match a '.' in the string:
+ pattern will match a ‘.’ in the string:
[[ . =~ [.] ]]
twice as much as possible, so shell quoting should be sufficient to
quote special pattern characters where that's necessary.
- The array variable 'BASH_REMATCH' records which parts of the string
- matched the pattern. The element of 'BASH_REMATCH' with index 0
+ The array variable ‘BASH_REMATCH’ records which parts of the string
+ matched the pattern. The element of ‘BASH_REMATCH’ with index 0
contains the portion of the string matching the entire regular
expression. Substrings matched by parenthesized subexpressions
within the regular expression are saved in the remaining
- 'BASH_REMATCH' indices. The element of 'BASH_REMATCH' with index N
+ ‘BASH_REMATCH’ indices. The element of ‘BASH_REMATCH’ with index N
is the portion of the string matching the Nth parenthesized
subexpression.
- Bash sets 'BASH_REMATCH' in the global scope; declaring it as a
+ Bash sets ‘BASH_REMATCH’ in the global scope; declaring it as a
local variable will lead to unexpected results.
Expressions may be combined using the following operators, listed
in decreasing order of precedence:
- '( EXPRESSION )'
+ ‘( EXPRESSION )’
Returns the value of EXPRESSION. This may be used to override
the normal precedence of operators.
- '! EXPRESSION'
+ ‘! EXPRESSION’
True if EXPRESSION is false.
- 'EXPRESSION1 && EXPRESSION2'
+ ‘EXPRESSION1 && EXPRESSION2’
True if both EXPRESSION1 and EXPRESSION2 are true.
- 'EXPRESSION1 || EXPRESSION2'
+ ‘EXPRESSION1 || EXPRESSION2’
True if either EXPRESSION1 or EXPRESSION2 is true.
- The '&&' and '||' operators do not evaluate EXPRESSION2 if the
+ The ‘&&’ and ‘||’ operators do not evaluate EXPRESSION2 if the
value of EXPRESSION1 is sufficient to determine the return value of
the entire conditional expression.
entire command list. For example, the output of all the commands in the
list may be redirected to a single stream.
-'()'
+‘()’
( LIST )
Placing a list of commands between parentheses forces the shell to
Since the LIST is executed in a subshell, variable assignments do
not remain in effect after the subshell completes.
-'{}'
+‘{}’
{ LIST; }
Placing a list of commands between curly braces causes the list to
In addition to the creation of a subshell, there is a subtle
difference between these two constructs due to historical reasons. The
braces are reserved words, so they must be separated from the LIST by
-'blank's or other shell metacharacters. The parentheses are operators,
+‘blank’s or other shell metacharacters. The parentheses are operators,
and are recognized as separate tokens by the shell even if they are not
separated from the LIST by whitespace.
3.2.6 Coprocesses
-----------------
-A 'coprocess' is a shell command preceded by the 'coproc' reserved word.
+A ‘coprocess’ is a shell command preceded by the ‘coproc’ reserved word.
A coprocess is executed asynchronously in a subshell, as if the command
-had been terminated with the '&' control operator, with a two-way pipe
+had been terminated with the ‘&’ control operator, with a two-way pipe
established between the executing shell and the coprocess.
The syntax for a coprocess is:
This creates a coprocess named NAME. COMMAND may be either a simple
command (*note Simple Commands::) or a compound command (*note Compound
Commands::). NAME is a shell variable name. If NAME is not supplied,
-the default name is 'COPROC'.
+the default name is ‘COPROC’.
The recommended form to use for a coprocess is
coproc NAME { COMMAND; }
This form is recommended because simple commands result in the coprocess
-always being named 'COPROC', and it is simpler to use and more complete
+always being named ‘COPROC’, and it is simpler to use and more complete
than the other compound commands.
There are other forms of coprocesses:
coproc SIMPLE-COMMAND
If COMMAND is a compound command, NAME is optional. The word following
-'coproc' determines whether that word is interpreted as a variable name:
+‘coproc’ determines whether that word is interpreted as a variable name:
it is interpreted as NAME if it is not a reserved word that introduces a
compound command. If COMMAND is a simple command, NAME is not allowed;
this is to avoid confusion between NAME and the first word of the simple
subshells.
The process ID of the shell spawned to execute the coprocess is
-available as the value of the variable 'NAME_PID'. The 'wait' builtin
+available as the value of the variable ‘NAME_PID’. The ‘wait’ builtin
command may be used to wait for the coprocess to terminate.
Since the coprocess is created as an asynchronous command, the
-'coproc' command always returns success. The return status of a
+‘coproc’ command always returns success. The return status of a
coprocess is the exit status of COMMAND.
\1f
read from files. GNU Parallel provides shorthand references to many of
the most common operations (input lines, various portions of the input
line, different ways to specify the input source, and so on). Parallel
-can replace 'xargs' or feed commands from its input sources to several
+can replace ‘xargs’ or feed commands from its input sources to several
different instances of Bash.
For a complete description, refer to the GNU Parallel documentation,
function FNAME [()] COMPOUND-COMMAND [ REDIRECTIONS ]
This defines a shell function named FNAME. The reserved word
-'function' is optional. If the 'function' reserved word is supplied,
-the parentheses are optional. The "body" of the function is the
+‘function’ is optional. If the ‘function’ reserved word is supplied,
+the parentheses are optional. The “body” of the function is the
compound command COMPOUND-COMMAND (*note Compound Commands::). That
command is usually a LIST enclosed between { and }, but may be any
-compound command listed above. If the 'function' reserved word is used,
+compound command listed above. If the ‘function’ reserved word is used,
but the parentheses are not supplied, the braces are recommended.
COMPOUND-COMMAND is executed whenever FNAME is specified as the name of
a simple command. When the shell is in POSIX mode (*note Bash POSIX
Mode::), FNAME must be a valid shell name and may not be the same as one
of the special builtins (*note Special Builtins::). In default mode, a
-function name can be any unquoted shell word that does not contain '$'.
+function name can be any unquoted shell word that does not contain ‘$’.
Any redirections (*note Redirections::) associated with the shell
function are performed when the function is executed. A function
-definition may be deleted using the '-f' option to the 'unset' builtin
+definition may be deleted using the ‘-f’ option to the ‘unset’ builtin
(*note Bourne Shell Builtins::).
The exit status of a function definition is zero unless a syntax
Note that for historical reasons, in the most common usage the curly
braces that surround the body of the function must be separated from the
-body by 'blank's or newlines. This is because the braces are reserved
+body by ‘blank’s or newlines. This is because the braces are reserved
words and are only recognized as such when they are separated from the
command list by whitespace or another shell metacharacter. Also, when
-using the braces, the LIST must be terminated by a semicolon, a '&', or
+using the braces, the LIST must be terminated by a semicolon, a ‘&’, or
a newline.
When a function is executed, the arguments to the function become the
positional parameters during its execution (*note Positional
-Parameters::). The special parameter '#' that expands to the number of
+Parameters::). The special parameter ‘#’ that expands to the number of
positional parameters is updated to reflect the change. Special
-parameter '0' is unchanged. The first element of the 'FUNCNAME'
+parameter ‘0’ is unchanged. The first element of the ‘FUNCNAME’
variable is set to the name of the function while the function is
executing.
All other aspects of the shell execution environment are identical
-between a function and its caller with these exceptions: the 'DEBUG' and
-'RETURN' traps are not inherited unless the function has been given the
-'trace' attribute using the 'declare' builtin or the '-o functrace'
-option has been enabled with the 'set' builtin, (in which case all
-functions inherit the 'DEBUG' and 'RETURN' traps), and the 'ERR' trap is
-not inherited unless the '-o errtrace' shell option has been enabled.
-*Note Bourne Shell Builtins::, for the description of the 'trap'
+between a function and its caller with these exceptions: the ‘DEBUG’ and
+‘RETURN’ traps are not inherited unless the function has been given the
+‘trace’ attribute using the ‘declare’ builtin or the ‘-o functrace’
+option has been enabled with the ‘set’ builtin, (in which case all
+functions inherit the ‘DEBUG’ and ‘RETURN’ traps), and the ‘ERR’ trap is
+not inherited unless the ‘-o errtrace’ shell option has been enabled.
+*Note Bourne Shell Builtins::, for the description of the ‘trap’
builtin.
- The 'FUNCNEST' variable, if set to a numeric value greater than 0,
+ The ‘FUNCNEST’ variable, if set to a numeric value greater than 0,
defines a maximum function nesting level. Function invocations that
exceed the limit cause the entire command to abort.
- If the builtin command 'return' is executed in a function, the
+ If the builtin command ‘return’ is executed in a function, the
function completes and execution resumes with the next command after the
-function call. Any command associated with the 'RETURN' trap is
+function call. Any command associated with the ‘RETURN’ trap is
executed before execution resumes. When a function completes, the
-values of the positional parameters and the special parameter '#' are
+values of the positional parameters and the special parameter ‘#’ are
restored to the values they had prior to the function's execution. If a
-numeric argument is given to 'return', that is the function's return
+numeric argument is given to ‘return’, that is the function's return
status; otherwise the function's return status is the exit status of the
-last command executed before the 'return'.
+last command executed before the ‘return’.
- Variables local to the function may be declared with the 'local'
-builtin ("local variables"). Ordinarily, variables and their values are
+ Variables local to the function may be declared with the ‘local’
+builtin (“local variables”). Ordinarily, variables and their values are
shared between a function and its caller. These variables are visible
only to the function and the commands it invokes. This is particularly
important when a shell function calls other functions.
- In the following description, the "current scope" is a currently-
+ In the following description, the “current scope” is a currently-
executing function. Previous scopes consist of that function's caller
and so on, back to the "global" scope, where the shell is not executing
any shell function. Consequently, a local variable at the current local
-scope is a variable declared using the 'local' or 'declare' builtins in
+scope is a variable declared using the ‘local’ or ‘declare’ builtins in
the function that is currently executing.
Local variables "shadow" variables with the same name declared at
refer to the local variable, leaving the global variable unmodified.
When the function returns, the global variable is once again visible.
- The shell uses "dynamic scoping" to control a variable's visibility
+ The shell uses “dynamic scoping” to control a variable's visibility
within functions. With dynamic scoping, visible variables and their
values are a result of the sequence of function calls that caused
execution to reach the current function. The value of a variable that a
function sees depends on its value within its caller, if any, whether
-that caller is the "global" scope or another shell function. This is
-also the value that a local variable declaration "shadows", and the
-value that is restored when the function returns.
+that caller is the global scope or another shell function. This is also
+the value that a local variable declaration shadows, and the value that
+is restored when the function returns.
- For example, if a variable 'var' is declared as local in function
-'func1', and 'func1' calls another function 'func2', references to 'var'
-made from within 'func2' will resolve to the local variable 'var' from
-'func1', shadowing any global variable named 'var'.
+ For example, if a variable ‘var’ is declared as local in function
+‘func1’, and ‘func1’ calls another function ‘func2’, references to ‘var’
+made from within ‘func2’ will resolve to the local variable ‘var’ from
+‘func1’, shadowing any global variable named ‘var’.
The following script demonstrates this behavior. When executed, the
script displays
var=global
func1
- The 'unset' builtin also acts using the same dynamic scope: if a
-variable is local to the current scope, 'unset' will unset it; otherwise
+ The ‘unset’ builtin also acts using the same dynamic scope: if a
+variable is local to the current scope, ‘unset’ will unset it; otherwise
the unset will refer to the variable found in any calling scope as
described above. If a variable at the current local scope is unset, it
will remain so (appearing as unset) until it is reset in that scope or
the variable at a previous scope will become visible. If the unset acts
on a variable at a previous scope, any instance of a variable with that
name that had been shadowed will become visible (see below how
-'localvar_unset'shell option changes this behavior).
+‘localvar_unset’shell option changes this behavior).
- Function names and definitions may be listed with the '-f' option to
-the 'declare' ('typeset') builtin command (*note Bash Builtins::). The
-'-F' option to 'declare' or 'typeset' will list the function names only
-(and optionally the source file and line number, if the 'extdebug' shell
+ Function names and definitions may be listed with the ‘-f’ option to
+the ‘declare’ (‘typeset’) builtin command (*note Bash Builtins::). The
+‘-F’ option to ‘declare’ or ‘typeset’ will list the function names only
+(and optionally the source file and line number, if the ‘extdebug’ shell
option is enabled). Functions may be exported so that child shell
processes (those created when executing a separate shell invocation)
-automatically have them defined with the '-f' option to the 'export'
+automatically have them defined with the ‘-f’ option to the ‘export’
builtin (*note Bourne Shell Builtins::).
- Functions may be recursive. The 'FUNCNEST' variable may be used to
+ Functions may be recursive. The ‘FUNCNEST’ variable may be used to
limit the depth of the function call stack and restrict the number of
function invocations. By default, no limit is placed on the number of
recursive calls.
* Positional Parameters:: The shell's command-line arguments.
* Special Parameters:: Parameters denoted by special characters.
-A "parameter" is an entity that stores values. It can be a 'name', a
-number, or one of the special characters listed below. A "variable" is
-a parameter denoted by a 'name'. A variable has a 'value' and zero or
-more 'attributes'. Attributes are assigned using the 'declare' builtin
-command (see the description of the 'declare' builtin in *note Bash
+A “parameter” is an entity that stores values. It can be a ‘name’, a
+number, or one of the special characters listed below. A “variable” is
+a parameter denoted by a ‘name’. A variable has a ‘value’ and zero or
+more ‘attributes’. Attributes are assigned using the ‘declare’ builtin
+command (see the description of the ‘declare’ builtin in *note Bash
Builtins::).
A parameter is set if it has been assigned a value. The null string
is a valid value. Once a variable is set, it may be unset only by using
-the 'unset' builtin command.
+the ‘unset’ builtin command.
A variable may be assigned to by a statement of the form
NAME=[VALUE]
If VALUE is not given, the variable is assigned the null string. All
VALUEs undergo tilde expansion, parameter and variable expansion,
command substitution, arithmetic expansion, and quote removal (*note
-Shell Parameter Expansion::). If the variable has its 'integer'
+Shell Parameter Expansion::). If the variable has its ‘integer’
attribute set, then VALUE is evaluated as an arithmetic expression even
-if the '$((...))' expansion is not used (*note Arithmetic Expansion::).
+if the ‘$((...))’ expansion is not used (*note Arithmetic Expansion::).
Word splitting and filename expansion are not performed. Assignment
-statements may also appear as arguments to the 'alias', 'declare',
-'typeset', 'export', 'readonly', and 'local' builtin commands
-("declaration" commands). When in POSIX mode (*note Bash POSIX Mode::),
+statements may also appear as arguments to the ‘alias’, ‘declare’,
+‘typeset’, ‘export’, ‘readonly’, and ‘local’ builtin commands
+(“declaration” commands). When in POSIX mode (*note Bash POSIX Mode::),
these builtins may appear in a command after one or more instances of
-the 'command' builtin and retain these assignment statement properties.
+the ‘command’ builtin and retain these assignment statement properties.
In the context where an assignment statement is assigning a value to
-a shell variable or array index (*note Arrays::), the '+=' operator can
+a shell variable or array index (*note Arrays::), the ‘+=’ operator can
be used to append to or add to the variable's previous value. This
-includes arguments to builtin commands such as 'declare' that accept
-assignment statements (declaration commands). When '+=' is applied to a
-variable for which the 'integer' attribute has been set, VALUE is
+includes arguments to builtin commands such as ‘declare’ that accept
+assignment statements (declaration commands). When ‘+=’ is applied to a
+variable for which the ‘integer’ attribute has been set, VALUE is
evaluated as an arithmetic expression and added to the variable's
-current value, which is also evaluated. When '+=' is applied to an
+current value, which is also evaluated. When ‘+=’ is applied to an
array variable using compound assignment (*note Arrays::), the
-variable's value is not unset (as it is when using '='), and new values
+variable's value is not unset (as it is when using ‘=’), and new values
are appended to the array beginning at one greater than the array's
maximum index (for indexed arrays), or added as additional key-value
pairs in an associative array. When applied to a string-valued
variable, VALUE is expanded and appended to the variable's value.
- A variable can be assigned the 'nameref' attribute using the '-n'
-option to the 'declare' or 'local' builtin commands (*note Bash
-Builtins::) to create a "nameref", or a reference to another variable.
+ A variable can be assigned the ‘nameref’ attribute using the ‘-n’
+option to the ‘declare’ or ‘local’ builtin commands (*note Bash
+Builtins::) to create a “nameref”, or a reference to another variable.
This allows variables to be manipulated indirectly. Whenever the
nameref variable is referenced, assigned to, unset, or has its
attributes modified (other than using or changing the nameref attribute
argument to the function. For instance, if a variable name is passed to
a shell function as its first argument, running
declare -n ref=$1
-inside the function creates a nameref variable 'ref' whose value is the
+inside the function creates a nameref variable ‘ref’ whose value is the
variable name passed as the first argument. References and assignments
-to 'ref', and changes to its attributes, are treated as references,
+to ‘ref’, and changes to its attributes, are treated as references,
assignments, and attribute modifications to the variable whose name was
-passed as '$1'.
+passed as ‘$1’.
- If the control variable in a 'for' loop has the nameref attribute,
+ If the control variable in a ‘for’ loop has the nameref attribute,
the list of words can be a list of shell variables, and a name reference
will be established for each word in the list, in turn, when the loop is
executed. Array variables cannot be given the nameref attribute.
However, nameref variables can reference array variables and subscripted
-array variables. Namerefs can be unset using the '-n' option to the
-'unset' builtin (*note Bourne Shell Builtins::). Otherwise, if 'unset'
+array variables. Namerefs can be unset using the ‘-n’ option to the
+‘unset’ builtin (*note Bourne Shell Builtins::). Otherwise, if ‘unset’
is executed with the name of a nameref variable as an argument, the
variable referenced by the nameref variable will be unset.
3.4.1 Positional Parameters
---------------------------
-A "positional parameter" is a parameter denoted by one or more digits,
-other than the single digit '0'. Positional parameters are assigned
+A “positional parameter” is a parameter denoted by one or more digits,
+other than the single digit ‘0’. Positional parameters are assigned
from the shell's arguments when it is invoked, and may be reassigned
-using the 'set' builtin command. Positional parameter 'N' may be
-referenced as '${N}', or as '$N' when 'N' consists of a single digit.
+using the ‘set’ builtin command. Positional parameter ‘N’ may be
+referenced as ‘${N}’, or as ‘$N’ when ‘N’ consists of a single digit.
Positional parameters may not be assigned to with assignment statements.
-The 'set' and 'shift' builtins are used to set and unset them (*note
+The ‘set’ and ‘shift’ builtins are used to set and unset them (*note
Shell Builtin Commands::). The positional parameters are temporarily
replaced when a shell function is executed (*note Shell Functions::).
The shell treats several parameters specially. These parameters may
only be referenced; assignment to them is not allowed.
-'*'
+‘*’
($*) Expands to the positional parameters, starting from one. When
the expansion is not within double quotes, each positional
parameter expands to a separate word. In contexts where it is
performed, those words are subject to further word splitting and
filename expansion. When the expansion occurs within double
quotes, it expands to a single word with the value of each
- parameter separated by the first character of the 'IFS' special
- variable. That is, '"$*"' is equivalent to '"$1C$2C..."', where C
- is the first character of the value of the 'IFS' variable. If
- 'IFS' is unset, the parameters are separated by spaces. If 'IFS'
+ parameter separated by the first character of the ‘IFS’ special
+ variable. That is, ‘"$*"’ is equivalent to ‘"$1C$2C..."’, where C
+ is the first character of the value of the ‘IFS’ variable. If
+ ‘IFS’ is unset, the parameters are separated by spaces. If ‘IFS’
is null, the parameters are joined without intervening separators.
-'@'
+‘@’
($@) Expands to the positional parameters, starting from one. In
contexts where word splitting is performed, this expands each
positional parameter to a separate word; if not within double
word with each positional parameter separated by a space. When the
expansion occurs within double quotes, and word splitting is
performed, each parameter expands to a separate word. That is,
- '"$@"' is equivalent to '"$1" "$2" ...'. If the double-quoted
+ ‘"$@"’ is equivalent to ‘"$1" "$2" ...’. If the double-quoted
expansion occurs within a word, the expansion of the first
parameter is joined with the beginning part of the original word,
and the expansion of the last parameter is joined with the last
part of the original word. When there are no positional
- parameters, '"$@"' and '$@' expand to nothing (i.e., they are
+ parameters, ‘"$@"’ and ‘$@’ expand to nothing (i.e., they are
removed).
-'#'
+‘#’
($#) Expands to the number of positional parameters in decimal.
-'?'
+‘?’
($?) Expands to the exit status of the most recently executed
foreground pipeline.
-'-'
+‘-’
($-, a hyphen.) Expands to the current option flags as specified
- upon invocation, by the 'set' builtin command, or those set by the
- shell itself (such as the '-i' option).
+ upon invocation, by the ‘set’ builtin command, or those set by the
+ shell itself (such as the ‘-i’ option).
-'$'
+‘$’
($$) Expands to the process ID of the shell. In a subshell, it
expands to the process ID of the invoking shell, not the subshell.
-'!'
+‘!’
($!) Expands to the process ID of the job most recently placed
into the background, whether executed as an asynchronous command or
- using the 'bg' builtin (*note Job Control Builtins::).
+ using the ‘bg’ builtin (*note Job Control Builtins::).
-'0'
+‘0’
($0) Expands to the name of the shell or shell script. This is set
at shell initialization. If Bash is invoked with a file of
- commands (*note Shell Scripts::), '$0' is set to the name of that
- file. If Bash is started with the '-c' option (*note Invoking
- Bash::), then '$0' is set to the first argument after the string to
+ commands (*note Shell Scripts::), ‘$0’ is set to the name of that
+ file. If Bash is started with the ‘-c’ option (*note Invoking
+ Bash::), then ‘$0’ is set to the first argument after the string to
be executed, if one is present. Otherwise, it is set to the
filename used to invoke Bash, as given by argument zero.
====================
Expansion is performed on the command line after it has been split into
-'token's. There are seven kinds of expansion performed:
+‘token’s. Bash performs these expansions:
- * brace expansion
- * tilde expansion
- * parameter and variable expansion
- * command substitution
- * arithmetic expansion
- * word splitting
- * filename expansion
+ • brace expansion
+ • tilde expansion
+ • parameter and variable expansion
+ • command substitution
+ • arithmetic expansion
+ • word splitting
+ • filename expansion
+ • quote removal
* Menu:
The order of expansions is: brace expansion; tilde expansion,
parameter and variable expansion, arithmetic expansion, and command
-substitution (done in a left-to-right fashion); word splitting; and
-filename expansion.
+substitution (done in a left-to-right fashion); word splitting; filename
+expansion; and quote removal.
On systems that can support it, there is an additional expansion
-available: "process substitution". This is performed at the same time
+available: “process substitution”. This is performed at the same time
as tilde, parameter, variable, and arithmetic expansion and command
substitution.
- After these expansions are performed, quote characters present in the
-original word are removed unless they have been quoted themselves
-("quote removal"). *Note Quote Removal:: for more details.
+ “Quote removal” is always performed last. It removes quote
+characters present in the original word, not ones resulting from one of
+the other expansions, unless they have been quoted themselves. *Note
+Quote Removal:: for more details.
Only brace expansion, word splitting, and filename expansion can
increase the number of words of the expansion; other expansions expand a
single word to a single word. The only exceptions to this are the
-expansions of '"$@"' and '$*' (*note Special Parameters::), and
-'"${NAME[@]}"' and '${NAME[*]}' (*note Arrays::).
+expansions of ‘"$@"’ and ‘$*’ (*note Special Parameters::), and
+‘"${NAME[@]}"’ and ‘${NAME[*]}’ (*note Arrays::).
\1f
File: bashref.info, Node: Brace Expansion, Next: Tilde Expansion, Up: Shell Expansions
---------------------
Brace expansion is a mechanism by which arbitrary strings may be
-generated. This mechanism is similar to "filename expansion" (*note
+generated. This mechanism is similar to “filename expansion” (*note
Filename Expansion::), but the filenames generated need not exist.
Patterns to be brace expanded take the form of an optional PREAMBLE,
followed by either a series of comma-separated strings or a sequence
bash$ echo a{d,c,b}e
ade ace abe
- A sequence expression takes the form '{X..Y[..INCR]}', where X and Y
+ A sequence expression takes the form ‘{X..Y[..INCR]}’, where X and Y
are either integers or letters, and INCR, an optional increment, is an
integer. When integers are supplied, the expression expands to each
-number between X and Y, inclusive. Supplied integers may be prefixed
-with '0' to force each term to have the same width. When either X or Y
-begins with a zero, the shell attempts to force all generated terms to
-contain the same number of digits, zero-padding where necessary. When
-letters are supplied, the expression expands to each character
-lexicographically between X and Y, inclusive, using the default C
-locale. Note that both X and Y must be of the same type (integer or
-letter). When the increment is supplied, it is used as the difference
-between each term. The default increment is 1 or -1 as appropriate.
+number between X and Y, inclusive. When either X or Y begins with a
+zero, the shell attempts to force all generated terms to contain the
+same number of digits, zero-padding where necessary. When letters are
+supplied, the expression expands to each character lexicographically
+between X and Y, inclusive, using the default C locale. Note that both
+X and Y must be of the same type (integer or letter). When the
+increment is supplied, it is used as the difference between each term.
+The default increment is 1 or -1 as appropriate.
Brace expansion is performed before any other expansions, and any
characters special to other expansions are preserved in the result. It
closing braces, and at least one unquoted comma or a valid sequence
expression. Any incorrectly formed brace expansion is left unchanged.
- A { or ',' may be quoted with a backslash to prevent its being
+ A { or ‘,’ may be quoted with a backslash to prevent its being
considered part of a brace expression. To avoid conflicts with
-parameter expansion, the string '${' is not considered eligible for
-brace expansion, and inhibits brace expansion until the closing '}'.
+parameter expansion, the string ‘${’ is not considered eligible for
+brace expansion, and inhibits brace expansion until the closing ‘}’.
This construct is typically used as shorthand when the common prefix
of the strings to be generated is longer than in the above example:
3.5.2 Tilde Expansion
---------------------
-If a word begins with an unquoted tilde character ('~'), all of the
+If a word begins with an unquoted tilde character (‘~’), all of the
characters up to the first unquoted slash (or all characters, if there
-is no unquoted slash) are considered a "tilde-prefix". If none of the
+is no unquoted slash) are considered a “tilde-prefix”. If none of the
characters in the tilde-prefix are quoted, the characters in the
-tilde-prefix following the tilde are treated as a possible "login name".
+tilde-prefix following the tilde are treated as a possible “login name”.
If this login name is the null string, the tilde is replaced with the
-value of the 'HOME' shell variable. If 'HOME' is unset, the home
+value of the ‘HOME’ shell variable. If ‘HOME’ is unset, the home
directory of the user executing the shell is substituted instead.
Otherwise, the tilde-prefix is replaced with the home directory
associated with the specified login name.
- If the tilde-prefix is '~+', the value of the shell variable 'PWD'
-replaces the tilde-prefix. If the tilde-prefix is '~-', the value of
-the shell variable 'OLDPWD', if it is set, is substituted.
+ If the tilde-prefix is ‘~+’, the value of the shell variable ‘PWD’
+replaces the tilde-prefix. If the tilde-prefix is ‘~-’, the value of
+the shell variable ‘OLDPWD’, if it is set, is substituted.
If the characters following the tilde in the tilde-prefix consist of
-a number N, optionally prefixed by a '+' or a '-', the tilde-prefix is
+a number N, optionally prefixed by a ‘+’ or a ‘-’, the tilde-prefix is
replaced with the corresponding element from the directory stack, as it
-would be displayed by the 'dirs' builtin invoked with the characters
+would be displayed by the ‘dirs’ builtin invoked with the characters
following tilde in the tilde-prefix as an argument (*note The Directory
Stack::). If the tilde-prefix, sans the tilde, consists of a number
-without a leading '+' or '-', '+' is assumed.
+without a leading ‘+’ or ‘-’, ‘+’ is assumed.
If the login name is invalid, or the tilde expansion fails, the word
is left unchanged.
Each variable assignment is checked for unquoted tilde-prefixes
-immediately following a ':' or the first '='. In these cases, tilde
+immediately following a ‘:’ or the first ‘=’. In these cases, tilde
expansion is also performed. Consequently, one may use filenames with
-tildes in assignments to 'PATH', 'MAILPATH', and 'CDPATH', and the shell
+tildes in assignments to ‘PATH’, ‘MAILPATH’, and ‘CDPATH’, and the shell
assigns the expanded value.
The following table shows how Bash treats unquoted tilde-prefixes:
-'~'
- The value of '$HOME'
-'~/foo'
- '$HOME/foo'
+‘~’
+ The value of ‘$HOME’
+‘~/foo’
+ ‘$HOME/foo’
-'~fred/foo'
- The subdirectory 'foo' of the home directory of the user 'fred'
+‘~fred/foo’
+ The subdirectory ‘foo’ of the home directory of the user ‘fred’
-'~+/foo'
- '$PWD/foo'
+‘~+/foo’
+ ‘$PWD/foo’
-'~-/foo'
- '${OLDPWD-'~-'}/foo'
+‘~-/foo’
+ ‘${OLDPWD-'~-'}/foo’
-'~N'
- The string that would be displayed by 'dirs +N'
+‘~N’
+ The string that would be displayed by ‘dirs +N’
-'~+N'
- The string that would be displayed by 'dirs +N'
+‘~+N’
+ The string that would be displayed by ‘dirs +N’
-'~-N'
- The string that would be displayed by 'dirs -N'
+‘~-N’
+ The string that would be displayed by ‘dirs -N’
Bash also performs tilde expansion on words satisfying the conditions
of variable assignments (*note Shell Parameters::) when they appear as
3.5.3 Shell Parameter Expansion
-------------------------------
-The '$' character introduces parameter expansion, command substitution,
+The ‘$’ character introduces parameter expansion, command substitution,
or arithmetic expansion. The parameter name or symbol to be expanded
may be enclosed in braces, which are optional but serve to protect the
variable to be expanded from characters immediately following it which
could be interpreted as part of the name.
- When braces are used, the matching ending brace is the first '}' not
+ When braces are used, the matching ending brace is the first ‘}’ not
escaped by a backslash or within a quoted string, and not within an
embedded arithmetic expansion, command substitution, or parameter
expansion.
uses the value formed by expanding the rest of PARAMETER as the new
PARAMETER; this is then expanded and that value is used in the rest of
the expansion, rather than the expansion of the original PARAMETER.
-This is known as 'indirect expansion'. The value is subject to tilde
+This is known as ‘indirect expansion’. The value is subject to tilde
expansion, parameter expansion, command substitution, and arithmetic
expansion. If PARAMETER is a nameref, this expands to the name of the
variable referenced by PARAMETER instead of performing the complete
parameter expansion, command substitution, and arithmetic expansion.
When not performing substring expansion, using the forms described
-below (e.g., ':-'), Bash tests for a parameter that is unset or null.
+below (e.g., ‘:-’), Bash tests for a parameter that is unset or null.
Omitting the colon results in a test only for a parameter that is unset.
Put another way, if the colon is included, the operator tests for both
PARAMETER's existence and that its value is not null; if the colon is
omitted, the operator tests only for existence.
-'${PARAMETER:-WORD}'
+‘${PARAMETER:−WORD}’
If PARAMETER is unset or null, the expansion of WORD is
substituted. Otherwise, the value of PARAMETER is substituted.
$ echo ${v:-unset-or-null}
unset-or-null
-'${PARAMETER:=WORD}'
+‘${PARAMETER:=WORD}’
If PARAMETER is unset or null, the expansion of WORD is assigned to
PARAMETER. The value of PARAMETER is then substituted. Positional
parameters and special parameters may not be assigned to in this
$ echo $var
DEFAULT
-'${PARAMETER:?WORD}'
+‘${PARAMETER:?WORD}’
If PARAMETER is null or unset, the expansion of WORD (or a message
to that effect if WORD is not present) is written to the standard
error and the shell, if it is not interactive, exits. Otherwise,
$ : ${var:?var is unset or null}
bash: var: var is unset or null
-'${PARAMETER:+WORD}'
+‘${PARAMETER:+WORD}’
If PARAMETER is null or unset, nothing is substituted, otherwise
the expansion of WORD is substituted.
$ echo ${var:+var is set and not null}
var is set and not null
-'${PARAMETER:OFFSET}'
-'${PARAMETER:OFFSET:LENGTH}'
+‘${PARAMETER:OFFSET}’
+‘${PARAMETER:OFFSET:LENGTH}’
This is referred to as Substring Expansion. It expands to up to
LENGTH characters of the value of PARAMETER starting at the
- character specified by OFFSET. If PARAMETER is '@' or '*', an
- indexed array subscripted by '@' or '*', or an associative array
+ character specified by OFFSET. If PARAMETER is ‘@’ or ‘*’, an
+ indexed array subscripted by ‘@’ or ‘*’, or an associative array
name, the results differ as described below. If LENGTH is omitted,
it expands to the substring of the value of PARAMETER starting at
the character specified by OFFSET and extending to the end of the
rather than a number of characters, and the expansion is the
characters between OFFSET and that result. Note that a negative
offset must be separated from the colon by at least one space to
- avoid being confused with the ':-' expansion.
+ avoid being confused with the ‘:-’ expansion.
Here are some examples illustrating substring expansion on
parameters and subscripted arrays:
$ echo ${array[0]: -7:-2}
bcdef
- If PARAMETER is '@' or '*', the result is LENGTH positional
+ If PARAMETER is ‘@’ or ‘*’, the result is LENGTH positional
parameters beginning at OFFSET. A negative OFFSET is taken
relative to one greater than the greatest positional parameter, so
an offset of -1 evaluates to the last positional parameter (or 0 if
$ echo ${@: -7:0}
- If PARAMETER is an indexed array name subscripted by '@' or '*',
+ If PARAMETER is an indexed array name subscripted by ‘@’ or ‘*’,
the result is the LENGTH members of the array beginning with
- '${PARAMETER[OFFSET]}'. A negative OFFSET is taken relative to one
+ ‘${PARAMETER[OFFSET]}’. A negative OFFSET is taken relative to one
greater than the maximum index of the specified array. It is an
expansion error if LENGTH evaluates to a number less than zero.
Substring indexing is zero-based unless the positional parameters
are used, in which case the indexing starts at 1 by default. If
- OFFSET is 0, and the positional parameters are used, '$0' is
+ OFFSET is 0, and the positional parameters are used, ‘$0’ is
prefixed to the list.
-'${!PREFIX*}'
-'${!PREFIX@}'
+‘${!PREFIX*}’
+‘${!PREFIX@}’
Expands to the names of variables whose names begin with PREFIX,
- separated by the first character of the 'IFS' special variable.
- When '@' is used and the expansion appears within double quotes,
+ separated by the first character of the ‘IFS’ special variable.
+ When ‘@’ is used and the expansion appears within double quotes,
each variable name expands to a separate word.
-'${!NAME[@]}'
-'${!NAME[*]}'
+‘${!NAME[@]}’
+‘${!NAME[*]}’
If NAME is an array variable, expands to the list of array indices
(keys) assigned in NAME. If NAME is not an array, expands to 0 if
- NAME is set and null otherwise. When '@' is used and the expansion
+ NAME is set and null otherwise. When ‘@’ is used and the expansion
appears within double quotes, each key expands to a separate word.
-'${#PARAMETER}'
+‘${#PARAMETER}’
The length in characters of the expanded value of PARAMETER is
- substituted. If PARAMETER is '*' or '@', the value substituted is
+ substituted. If PARAMETER is ‘*’ or ‘@’, the value substituted is
the number of positional parameters. If PARAMETER is an array name
- subscripted by '*' or '@', the value substituted is the number of
+ subscripted by ‘*’ or ‘@’, the value substituted is the number of
elements in the array. If PARAMETER is an indexed array name
subscripted by a negative number, that number is interpreted as
relative to one greater than the maximum index of PARAMETER, so
negative indices count back from the end of the array, and an index
of -1 references the last element.
-'${PARAMETER#WORD}'
-'${PARAMETER##WORD}'
+‘${PARAMETER#WORD}’
+‘${PARAMETER##WORD}’
The WORD is expanded to produce a pattern and matched according to
the rules described below (*note Pattern Matching::). If the
pattern matches the beginning of the expanded value of PARAMETER,
then the result of the expansion is the expanded value of PARAMETER
- with the shortest matching pattern (the '#' case) or the longest
- matching pattern (the '##' case) deleted. If PARAMETER is '@' or
- '*', the pattern removal operation is applied to each positional
+ with the shortest matching pattern (the ‘#’ case) or the longest
+ matching pattern (the ‘##’ case) deleted. If PARAMETER is ‘@’ or
+ ‘*’, the pattern removal operation is applied to each positional
parameter in turn, and the expansion is the resultant list. If
- PARAMETER is an array variable subscripted with '@' or '*', the
+ PARAMETER is an array variable subscripted with ‘@’ or ‘*’, the
pattern removal operation is applied to each member of the array in
turn, and the expansion is the resultant list.
-'${PARAMETER%WORD}'
-'${PARAMETER%%WORD}'
+‘${PARAMETER%WORD}’
+‘${PARAMETER%%WORD}’
The WORD is expanded to produce a pattern and matched according to
the rules described below (*note Pattern Matching::). If the
pattern matches a trailing portion of the expanded value of
PARAMETER, then the result of the expansion is the value of
- PARAMETER with the shortest matching pattern (the '%' case) or the
- longest matching pattern (the '%%' case) deleted. If PARAMETER is
- '@' or '*', the pattern removal operation is applied to each
+ PARAMETER with the shortest matching pattern (the ‘%’ case) or the
+ longest matching pattern (the ‘%%’ case) deleted. If PARAMETER is
+ ‘@’ or ‘*’, the pattern removal operation is applied to each
positional parameter in turn, and the expansion is the resultant
- list. If PARAMETER is an array variable subscripted with '@' or
- '*', the pattern removal operation is applied to each member of the
+ list. If PARAMETER is an array variable subscripted with ‘@’ or
+ ‘*’, the pattern removal operation is applied to each member of the
array in turn, and the expansion is the resultant list.
-'${PARAMETER/PATTERN/STRING}'
-'${PARAMETER//PATTERN/STRING}'
-'${PARAMETER/#PATTERN/STRING}'
-'${PARAMETER/%PATTERN/STRING}'
+‘${PARAMETER/PATTERN/STRING}’
+‘${PARAMETER//PATTERN/STRING}’
+‘${PARAMETER/#PATTERN/STRING}’
+‘${PARAMETER/%PATTERN/STRING}’
The PATTERN is expanded to produce a pattern just as in filename
expansion. PARAMETER is expanded and the longest match of PATTERN
against its value is replaced with STRING. STRING undergoes tilde
In the first form above, only the first match is replaced. If
there are two slashes separating PARAMETER and PATTERN (the second
form above), all matches of PATTERN are replaced with STRING. If
- PATTERN is preceded by '#' (the third form above), it must match at
+ PATTERN is preceded by ‘#’ (the third form above), it must match at
the beginning of the expanded value of PARAMETER. If PATTERN is
- preceded by '%' (the fourth form above), it must match at the end
+ preceded by ‘%’ (the fourth form above), it must match at the end
of the expanded value of PARAMETER. If the expansion of STRING is
null, matches of PATTERN are deleted. If STRING is null, matches
- of PATTERN are deleted and the '/' following PATTERN may be
+ of PATTERN are deleted and the ‘/’ following PATTERN may be
omitted.
- If the 'patsub_replacement' shell option is enabled using 'shopt',
- any unquoted instances of '&' in STRING are replaced with the
+ If the ‘patsub_replacement’ shell option is enabled using ‘shopt’,
+ any unquoted instances of ‘&’ in STRING are replaced with the
matching portion of PATTERN. This is intended to duplicate a
- common 'sed' idiom.
+ common ‘sed’ idiom.
Quoting any part of STRING inhibits replacement in the expansion of
the quoted portion, including replacement strings stored in shell
- variables. Backslash will escape '&' in STRING; the backslash is
- removed in order to permit a literal '&' in the replacement string.
+ variables. Backslash will escape ‘&’ in STRING; the backslash is
+ removed in order to permit a literal ‘&’ in the replacement string.
Users should take care if STRING is double-quoted to avoid unwanted
interactions between the backslash and double-quoting, since
backslash has special meaning within double quotes. Pattern
- substitution performs the check for unquoted '&' after expanding
+ substitution performs the check for unquoted ‘&’ after expanding
STRING, so users should ensure to properly quote any occurrences of
- '&' they want to be taken literally in the replacement and ensure
- any instances of '&' they want to be replaced are unquoted.
+ ‘&’ they want to be taken literally in the replacement and ensure
+ any instances of ‘&’ they want to be replaced are unquoted.
For instance,
a context that doesn't take any enclosing double quotes into
account.
- Since backslash can escape '&', it can also escape a backslash in
- the replacement string. This means that '\\' will insert a literal
- backslash into the replacement, so these two 'echo' commands
+ Since backslash can escape ‘&’, it can also escape a backslash in
+ the replacement string. This means that ‘\\’ will insert a literal
+ backslash into the replacement, so these two ‘echo’ commands
var=abcdef
rep='\\&xyz'
echo ${var/abc/\\&xyz}
echo ${var/abc/$rep}
- will both output '\abcxyzdef'.
+ will both output ‘\abcxyzdef’.
It should rarely be necessary to enclose only STRING in double
quotes.
- If the 'nocasematch' shell option (see the description of 'shopt'
+ If the ‘nocasematch’ shell option (see the description of ‘shopt’
in *note The Shopt Builtin::) is enabled, the match is performed
without regard to the case of alphabetic characters. If PARAMETER
- is '@' or '*', the substitution operation is applied to each
+ is ‘@’ or ‘*’, the substitution operation is applied to each
positional parameter in turn, and the expansion is the resultant
- list. If PARAMETER is an array variable subscripted with '@' or
- '*', the substitution operation is applied to each member of the
+ list. If PARAMETER is an array variable subscripted with ‘@’ or
+ ‘*’, the substitution operation is applied to each member of the
array in turn, and the expansion is the resultant list.
-'${PARAMETER^PATTERN}'
-'${PARAMETER^^PATTERN}'
-'${PARAMETER,PATTERN}'
-'${PARAMETER,,PATTERN}'
+‘${PARAMETER^PATTERN}’
+‘${PARAMETER^^PATTERN}’
+‘${PARAMETER,PATTERN}’
+‘${PARAMETER,,PATTERN}’
This expansion modifies the case of alphabetic characters in
PARAMETER. The PATTERN is expanded to produce a pattern just as in
filename expansion. Each character in the expanded value of
pattern, its case is converted. The pattern should not attempt to
match more than one character.
- The '^' operator converts lowercase letters matching PATTERN to
- uppercase; the ',' operator converts matching uppercase letters to
- lowercase. The '^^' and ',,' expansions convert each matched
- character in the expanded value; the '^' and ',' expansions match
+ The ‘^’ operator converts lowercase letters matching PATTERN to
+ uppercase; the ‘,’ operator converts matching uppercase letters to
+ lowercase. The ‘^^’ and ‘,,’ expansions convert each matched
+ character in the expanded value; the ‘^’ and ‘,’ expansions match
and convert only the first character in the expanded value. If
- PATTERN is omitted, it is treated like a '?', which matches every
+ PATTERN is omitted, it is treated like a ‘?’, which matches every
character.
- If PARAMETER is '@' or '*', the case modification operation is
+ If PARAMETER is ‘@’ or ‘*’, the case modification operation is
applied to each positional parameter in turn, and the expansion is
the resultant list. If PARAMETER is an array variable subscripted
- with '@' or '*', the case modification operation is applied to each
+ with ‘@’ or ‘*’, the case modification operation is applied to each
member of the array in turn, and the expansion is the resultant
list.
-'${PARAMETER@OPERATOR}'
+‘${PARAMETER@OPERATOR}’
The expansion is either a transformation of the value of PARAMETER
or information about PARAMETER itself, depending on the value of
OPERATOR. Each OPERATOR is a single letter:
- 'U'
+ ‘U’
The expansion is a string that is the value of PARAMETER with
lowercase alphabetic characters converted to uppercase.
- 'u'
+ ‘u’
The expansion is a string that is the value of PARAMETER with
the first character converted to uppercase, if it is
alphabetic.
- 'L'
+ ‘L’
The expansion is a string that is the value of PARAMETER with
uppercase alphabetic characters converted to lowercase.
- 'Q'
+ ‘Q’
The expansion is a string that is the value of PARAMETER
quoted in a format that can be reused as input.
- 'E'
+ ‘E’
The expansion is a string that is the value of PARAMETER with
- backslash escape sequences expanded as with the '$'...''
+ backslash escape sequences expanded as with the ‘$'...'’
quoting mechanism.
- 'P'
+ ‘P’
The expansion is a string that is the result of expanding the
value of PARAMETER as if it were a prompt string (*note
Controlling the Prompt::).
- 'A'
+ ‘A’
The expansion is a string in the form of an assignment
- statement or 'declare' command that, if evaluated, will
+ statement or ‘declare’ command that, if evaluated, will
recreate PARAMETER with its attributes and value.
- 'K'
+ ‘K’
Produces a possibly-quoted version of the value of PARAMETER,
except that it prints the values of indexed and associative
arrays as a sequence of quoted key-value pairs (*note
Arrays::).
- 'a'
+ ‘a’
The expansion is a string consisting of flag values
representing PARAMETER's attributes.
- 'k'
- Like the 'K' transformation, but expands the keys and values
+ ‘k’
+ Like the ‘K’ transformation, but expands the keys and values
of indexed and associative arrays to separate words after word
splitting.
- If PARAMETER is '@' or '*', the operation is applied to each
+ If PARAMETER is ‘@’ or ‘*’, the operation is applied to each
positional parameter in turn, and the expansion is the resultant
- list. If PARAMETER is an array variable subscripted with '@' or
- '*', the operation is applied to each member of the array in turn,
+ list. If PARAMETER is an array variable subscripted with ‘@’ or
+ ‘*’, the operation is applied to each member of the array in turn,
and the expansion is the resultant list.
The result of the expansion is subject to word splitting and
environment and replacing the command substitution with the standard
output of the command, with any trailing newlines deleted. Embedded
newlines are not deleted, but they may be removed during word splitting.
-The command substitution '$(cat FILE)' can be replaced by the equivalent
-but faster '$(< FILE)'.
+The command substitution ‘$(cat FILE)’ can be replaced by the equivalent
+but faster ‘$(< FILE)’.
With the old-style backquote form of substitution, backslash retains
-its literal meaning except when followed by '$', '`', or '\'. The first
+its literal meaning except when followed by ‘$’, ‘`’, or ‘\’. The first
backquote not preceded by a backslash terminates the command
-substitution. When using the '$(COMMAND)' form, all characters between
+substitution. When using the ‘$(COMMAND)’ form, all characters between
the parentheses make up the command; none are treated specially.
There is an alternate form of command substitution:
its output, again with trailing newlines removed.
The character C following the open brace must be a space, tab,
-newline, or '|', and the close brace must be in a position where a
+newline, or ‘|’, and the close brace must be in a position where a
reserved word may appear (i.e., preceded by a command terminator such as
semicolon). Bash allows the close brace to be joined to the remaining
characters in the word without being followed by a shell metacharacter
Any side effects of COMMAND take effect immediately in the current
execution environment and persist in the current environment after the
-command completes (e.g., the 'exit' builtin will exit the shell).
+command completes (e.g., the ‘exit’ builtin will exit the shell).
This type of command substitution superficially resembles executing
an unnamed shell function: local variables are created as when a shell
-function is executing, and the 'return' builtin forces COMMAND to
+function is executing, and the ‘return’ builtin forces COMMAND to
complete; however, the rest of the execution environment, including the
positional parameters, is shared with the caller.
- If the first character following the open brace is a '|', the
-construct expands to the value of the 'REPLY' shell variable after
+ If the first character following the open brace is a ‘|’, the
+construct expands to the value of the ‘REPLY’ shell variable after
COMMAND executes, without removing any trailing newlines, and the
standard output of COMMAND remains the same as in the calling shell.
-Bash creates 'REPLY' as an initially-unset local variable when COMMAND
-executes, and restores 'REPLY' to the value it had before the command
+Bash creates ‘REPLY’ as an initially-unset local variable when COMMAND
+executes, and restores ‘REPLY’ to the value it had before the command
substitution after COMMAND completes, as with any local variable.
- For example, this construct expands to '12345', and leaves the shell
-variable 'X' unchanged in the current execution environment:
+ For example, this construct expands to ‘12345’, and leaves the shell
+variable ‘X’ unchanged in the current execution environment:
${ local X=12345 ; echo $X; }
-(not declaring 'X' as local would modify its value in the current
+(not declaring ‘X’ as local would modify its value in the current
environment, as with normal shell function execution), while this
-construct does not require any output to expand to '12345':
+construct does not require any output to expand to ‘12345’:
${| REPLY=12345; }
-and restores 'REPLY' to the value it had before the command
+and restores ‘REPLY’ to the value it had before the command
substitution.
Command substitutions may be nested. To nest when using the
>(LIST)
The process LIST is run asynchronously, and its input or output appears
as a filename. This filename is passed as an argument to the current
-command as the result of the expansion. If the '>(LIST)' form is used,
-writing to the file will provide input for LIST. If the '<(LIST)' form
+command as the result of the expansion. If the ‘>(LIST)’ form is used,
+writing to the file will provide input for LIST. If the ‘<(LIST)’ form
is used, the file passed as an argument should be read to obtain the
-output of LIST. Note that no space may appear between the '<' or '>'
+output of LIST. Note that no space may appear between the ‘<’ or ‘>’
and the left parenthesis, otherwise the construct would be interpreted
as a redirection. Process substitution is supported on systems that
-support named pipes (FIFOs) or the '/dev/fd' method of naming open
+support named pipes (FIFOs) or the ‘/dev/fd’ method of naming open
files.
When available, process substitution is performed simultaneously with
substitution, and arithmetic expansion that did not occur within double
quotes for word splitting.
- The shell treats each character of '$IFS' as a delimiter, and splits
+ The shell treats each character of ‘$IFS’ as a delimiter, and splits
the results of the other expansions into words using these characters as
field terminators.
- If 'IFS' is unset, or its value is exactly '<space><tab><newline>',
-the default, then sequences of 'space', 'tab', and 'newline' at the
+ If ‘IFS’ is unset, or its value is exactly ‘<space><tab><newline>’,
+the default, then sequences of ‘space’, ‘tab’, and ‘newline’ at the
beginning and end of the results of the previous expansions are ignored,
-and any sequence of 'IFS' characters not at the beginning or end serves
-to delimit words. If 'IFS' has a value other than the default, then
-sequences of the whitespace characters 'space', 'tab', and 'newline' are
+and any sequence of ‘IFS’ characters not at the beginning or end serves
+to delimit words. If ‘IFS’ has a value other than the default, then
+sequences of the whitespace characters ‘space’, ‘tab’, and ‘newline’ are
ignored at the beginning and end of the word, as long as the whitespace
-character is in the value of 'IFS' (an 'IFS' whitespace character). Any
-character in 'IFS' that is not 'IFS' whitespace, along with any adjacent
-'IFS' whitespace characters, delimits a field. A sequence of 'IFS'
+character is in the value of ‘IFS’ (an ‘IFS’ whitespace character). Any
+character in ‘IFS’ that is not ‘IFS’ whitespace, along with any adjacent
+‘IFS’ whitespace characters, delimits a field. A sequence of ‘IFS’
whitespace characters is also treated as a delimiter.
- If the value of 'IFS' is null, no word splitting occurs. If 'IFS' is
+ If the value of ‘IFS’ is null, no word splitting occurs. If ‘IFS’ is
unset, word splitting behaves as if it contained the default value
-'<space><tab><newline>'.
+‘<space><tab><newline>’.
- Explicit null arguments ('""' or '''') are retained and passed to
+ Explicit null arguments (‘""’ or ‘''’) are retained and passed to
commands as empty strings. Unquoted implicit null arguments, resulting
from the expansion of parameters that have no values, are removed. If a
parameter with no value is expanded within double quotes, a null
argument results and is retained and passed to a command as an empty
string. When a quoted null argument appears as part of a word whose
expansion is non-null, the null argument is removed. That is, the word
-'-d''' becomes '-d' after word splitting and null argument removal.
+‘-d''’ becomes ‘-d’ after word splitting and null argument removal.
Note that if no expansion occurs, no splitting is performed.
* Pattern Matching:: How the shell matches patterns.
-After word splitting, unless the '-f' option has been set (*note The Set
-Builtin::), Bash scans each word for the characters '*', '?', and '['.
+After word splitting, unless the ‘-f’ option has been set (*note The Set
+Builtin::), Bash scans each word for the characters ‘*’, ‘?’, and ‘[’.
If one of these characters appears, and is not quoted, then the word is
regarded as a PATTERN, and replaced with an alphabetically sorted list
of filenames matching the pattern (*note Pattern Matching::). If no
-matching filenames are found, and the shell option 'nullglob' is
-disabled, the word is left unchanged. If the 'nullglob' option is set,
-and no matches are found, the word is removed. If the 'failglob' shell
+matching filenames are found, and the shell option ‘nullglob’ is
+disabled, the word is left unchanged. If the ‘nullglob’ option is set,
+and no matches are found, the word is removed. If the ‘failglob’ shell
option is set, and no matches are found, an error message is printed and
-the command is not executed. If the shell option 'nocaseglob' is
+the command is not executed. If the shell option ‘nocaseglob’ is
enabled, the match is performed without regard to the case of alphabetic
characters.
- When a pattern is used for filename expansion, the character '.' at
+ When a pattern is used for filename expansion, the character ‘.’ at
the start of a filename or immediately following a slash must be matched
-explicitly, unless the shell option 'dotglob' is set. In order to match
-the filenames '.' and '..', the pattern must begin with '.' (for
-example, '.?'), even if 'dotglob' is set. If the 'globskipdots' shell
-option is enabled, the filenames '.' and '..' are never matched, even if
-the pattern begins with a '.'. When not matching filenames, the '.'
+explicitly, unless the shell option ‘dotglob’ is set. In order to match
+the filenames ‘.’ and ‘..’, the pattern must begin with ‘.’ (for
+example, ‘.?’), even if ‘dotglob’ is set. If the ‘globskipdots’ shell
+option is enabled, the filenames ‘.’ and ‘..’ never match, even if the
+pattern begins with a ‘.’. When not matching filenames, the ‘.’
character is not treated specially.
When matching a filename, the slash character must always be matched
can be matched by a special pattern character as described below (*note
Pattern Matching::).
- See the description of 'shopt' in *note The Shopt Builtin::, for a
-description of the 'nocaseglob', 'nullglob', 'globskipdots', 'failglob',
-and 'dotglob' options.
-
- The 'GLOBIGNORE' shell variable may be used to restrict the set of
-file names matching a pattern. If 'GLOBIGNORE' is set, each matching
-file name that also matches one of the patterns in 'GLOBIGNORE' is
-removed from the list of matches. If the 'nocaseglob' option is set,
-the matching against the patterns in 'GLOBIGNORE' is performed without
-regard to case. The filenames '.' and '..' are always ignored when
-'GLOBIGNORE' is set and not null. However, setting 'GLOBIGNORE' to a
-non-null value has the effect of enabling the 'dotglob' shell option, so
-all other filenames beginning with a '.' will match. To get the old
-behavior of ignoring filenames beginning with a '.', make '.*' one of
-the patterns in 'GLOBIGNORE'. The 'dotglob' option is disabled when
-'GLOBIGNORE' is unset.
+ See the description of ‘shopt’ in *note The Shopt Builtin::, for a
+description of the ‘nocaseglob’, ‘nullglob’, ‘globskipdots’, ‘failglob’,
+and ‘dotglob’ options.
+
+ The ‘GLOBIGNORE’ shell variable may be used to restrict the set of
+file names matching a pattern. If ‘GLOBIGNORE’ is set, each matching
+file name that also matches one of the patterns in ‘GLOBIGNORE’ is
+removed from the list of matches. If the ‘nocaseglob’ option is set,
+the matching against the patterns in ‘GLOBIGNORE’ is performed without
+regard to case. The filenames ‘.’ and ‘..’ are always ignored when
+‘GLOBIGNORE’ is set and not null. However, setting ‘GLOBIGNORE’ to a
+non-null value has the effect of enabling the ‘dotglob’ shell option, so
+all other filenames beginning with a ‘.’ will match. To get the old
+behavior of ignoring filenames beginning with a ‘.’, make ‘.*’ one of
+the patterns in ‘GLOBIGNORE’. The ‘dotglob’ option is disabled when
+‘GLOBIGNORE’ is unset.
After the pattern is expanded and matched against filenames, the
-value of the 'GLOBSORT' variable controls how the results are sorted, as
+value of the ‘GLOBSORT’ variable controls how the results are sorted, as
described below (*note Bash Variables::).
\1f
characters must be quoted if they are to be matched literally.
The special pattern characters have the following meanings:
-'*'
- Matches any string, including the null string. When the 'globstar'
- shell option is enabled, and '*' is used in a filename expansion
- context, two adjacent '*'s used as a single pattern will match all
+‘*’
+ Matches any string, including the null string. When the ‘globstar’
+ shell option is enabled, and ‘*’ is used in a filename expansion
+ context, two adjacent ‘*’s used as a single pattern will match all
files and zero or more directories and subdirectories. If followed
- by a '/', two adjacent '*'s will match only directories and
+ by a ‘/’, two adjacent ‘*’s will match only directories and
subdirectories.
-'?'
+‘?’
Matches any single character.
-'[...]'
+‘[...]’
Matches any one of the enclosed characters. A pair of characters
separated by a hyphen denotes a RANGE EXPRESSION; any character
that falls between those two characters, inclusive, using the
current locale's collating sequence and character set, is matched.
- If the first character following the '[' is a '!' or a '^' then any
- character not enclosed is matched. A '-' may be matched by
- including it as the first or last character in the set. A ']' may
+ If the first character following the ‘[’ is a ‘!’ or a ‘^’ then any
+ character not enclosed is matched. A ‘−’ may be matched by
+ including it as the first or last character in the set. A ‘]’ may
be matched by including it as the first character in the set. The
sorting order of characters in range expressions, and the
characters included in the range, are determined by the current
- locale and the values of the 'LC_COLLATE' and 'LC_ALL' shell
+ locale and the values of the ‘LC_COLLATE’ and ‘LC_ALL’ shell
variables, if set.
- For example, in the default C locale, '[a-dx-z]' is equivalent to
- '[abcdxyz]'. Many locales sort characters in dictionary order, and
- in these locales '[a-dx-z]' is typically not equivalent to
- '[abcdxyz]'; it might be equivalent to '[aBbCcDdxYyZz]', for
+ For example, in the default C locale, ‘[a-dx-z]’ is equivalent to
+ ‘[abcdxyz]’. Many locales sort characters in dictionary order, and
+ in these locales ‘[a-dx-z]’ is typically not equivalent to
+ ‘[abcdxyz]’; it might be equivalent to ‘[aBbCcDdxYyZz]’, for
example. To obtain the traditional interpretation of ranges in
bracket expressions, you can force the use of the C locale by
- setting the 'LC_COLLATE' or 'LC_ALL' environment variable to the
- value 'C', or enable the 'globasciiranges' shell option.
+ setting the ‘LC_COLLATE’ or ‘LC_ALL’ environment variable to the
+ value ‘C’, or enable the ‘globasciiranges’ shell option.
- Within '[' and ']', "character classes" can be specified using the
- syntax '[:'CLASS':]', where CLASS is one of the following classes
+ Within ‘[’ and ‘]’, “character classes” can be specified using the
+ syntax ‘[:’CLASS‘:]’, where CLASS is one of the following classes
defined in the POSIX standard:
alnum alpha ascii blank cntrl digit graph lower
print punct space upper word xdigit
A character class matches any character belonging to that class.
- The 'word' character class matches letters, digits, and the
- character '_'.
+ The ‘word’ character class matches letters, digits, and the
+ character ‘_’.
- Within '[' and ']', an "equivalence class" can be specified using
- the syntax '[='C'=]', which matches all characters with the same
+ Within ‘[’ and ‘]’, an “equivalence class” can be specified using
+ the syntax ‘[=’C‘=]’, which matches all characters with the same
collation weight (as defined by the current locale) as the
character C.
- Within '[' and ']', the syntax '[.'SYMBOL'.]' matches the collating
+ Within ‘[’ and ‘]’, the syntax ‘[.’SYMBOL‘.]’ matches the collating
symbol SYMBOL.
- If the 'extglob' shell option is enabled using the 'shopt' builtin,
+ If the ‘extglob’ shell option is enabled using the ‘shopt’ builtin,
the shell recognizes several extended pattern matching operators. In
the following description, a PATTERN-LIST is a list of one or more
-patterns separated by a '|'. When matching filenames, the 'dotglob'
+patterns separated by a ‘|’. When matching filenames, the ‘dotglob’
shell option determines the set of filenames that are tested, as
described above. Composite patterns may be formed using one or more of
the following sub-patterns:
-'?(PATTERN-LIST)'
+‘?(PATTERN-LIST)’
Matches zero or one occurrence of the given patterns.
-'*(PATTERN-LIST)'
+‘*(PATTERN-LIST)’
Matches zero or more occurrences of the given patterns.
-'+(PATTERN-LIST)'
+‘+(PATTERN-LIST)’
Matches one or more occurrences of the given patterns.
-'@(PATTERN-LIST)'
+‘@(PATTERN-LIST)’
Matches one of the given patterns.
-'!(PATTERN-LIST)'
+‘!(PATTERN-LIST)’
Matches anything except one of the given patterns.
- The 'extglob' option changes the behavior of the parser, since the
+ The ‘extglob’ option changes the behavior of the parser, since the
parentheses are normally treated as operators with syntactic meaning.
To ensure that extended matching patterns are parsed correctly, make
-sure that 'extglob' is enabled before parsing constructs containing the
+sure that ‘extglob’ is enabled before parsing constructs containing the
patterns, including shell functions and command substitutions.
- When matching filenames, the 'dotglob' shell option determines the
-set of filenames that are tested: when 'dotglob' is enabled, the set of
-filenames includes all files beginning with '.', but the filenames '.'
-and '..' must be matched by a pattern or sub-pattern that begins with a
+ When matching filenames, the ‘dotglob’ shell option determines the
+set of filenames that are tested: when ‘dotglob’ is enabled, the set of
+filenames includes all files beginning with ‘.’, but the filenames ‘.’
+and ‘..’ must be matched by a pattern or sub-pattern that begins with a
dot; when it is disabled, the set does not include any filenames
-beginning with "." unless the pattern or sub-pattern begins with a '.'.
-As above, '.' only has a special meaning when matching filenames.
+beginning with "." unless the pattern or sub-pattern begins with a ‘.’.
+As above, ‘.’ only has a special meaning when matching filenames.
Complicated extended pattern matching against long strings is slow,
especially when the patterns contain alternations and the strings
-------------------
After the preceding expansions, all unquoted occurrences of the
-characters '\', ''', and '"' that did not result from one of the above
+characters ‘\’, ‘'’, and ‘"’ that did not result from one of the above
expansions are removed.
\1f
3.6 Redirections
================
-Before a command is executed, its input and output may be "redirected"
-using a special notation interpreted by the shell. "Redirection" allows
+Before a command is executed, its input and output may be “redirected”
+using a special notation interpreted by the shell. “Redirection” allows
commands' file handles to be duplicated, opened, closed, made to refer
to different files, and can change the files the command reads from and
writes to. Redirection may also be used to modify file handles in the
<&- is preceded by {VARNAME}, the value of VARNAME defines the file
descriptor to close. If {VARNAME} is supplied, the redirection persists
beyond the scope of the command, allowing the shell programmer to manage
-the file descriptor's lifetime manually. The 'varredir_close' shell
+the file descriptor's lifetime manually. The ‘varredir_close’ shell
option manages this behavior (*note The Shopt Builtin::).
In the following descriptions, if the file descriptor number is
-omitted, and the first character of the redirection operator is '<', the
+omitted, and the first character of the redirection operator is ‘<’, the
redirection refers to the standard input (file descriptor 0). If the
-first character of the redirection operator is '>', the redirection
+first character of the redirection operator is ‘>’, the redirection
refers to the standard output (file descriptor 1).
The word following the redirection operator in the following
use them; otherwise it will emulate them internally with the behavior
described below.
-'/dev/fd/FD'
+‘/dev/fd/FD’
If FD is a valid integer, file descriptor FD is duplicated.
-'/dev/stdin'
+‘/dev/stdin’
File descriptor 0 is duplicated.
-'/dev/stdout'
+‘/dev/stdout’
File descriptor 1 is duplicated.
-'/dev/stderr'
+‘/dev/stderr’
File descriptor 2 is duplicated.
-'/dev/tcp/HOST/PORT'
+‘/dev/tcp/HOST/PORT’
If HOST is a valid hostname or Internet address, and PORT is an
integer port number or service name, Bash attempts to open the
corresponding TCP socket.
-'/dev/udp/HOST/PORT'
+‘/dev/udp/HOST/PORT’
If HOST is a valid hostname or Internet address, and PORT is an
integer port number or service name, Bash attempts to open the
corresponding UDP socket.
-----------------------
Redirection of input causes the file whose name results from the
-expansion of WORD to be opened for reading on file descriptor 'n', or
-the standard input (file descriptor 0) if 'n' is not specified.
+expansion of WORD to be opened for reading on file descriptor ‘n’, or
+the standard input (file descriptor 0) if ‘n’ is not specified.
The general format for redirecting input is:
[N]<WORD
The general format for redirecting output is:
[N]>[|]WORD
- If the redirection operator is '>', and the 'noclobber' option to the
-'set' builtin has been enabled, the redirection will fail if the file
+ If the redirection operator is ‘>’, and the ‘noclobber’ option to the
+‘set’ builtin has been enabled, the redirection will fail if the file
whose name results from the expansion of WORD exists and is a regular
-file. If the redirection operator is '>|', or the redirection operator
-is '>' and the 'noclobber' option is not enabled, the redirection is
+file. If the redirection operator is ‘>|’, or the redirection operator
+is ‘>’ and the ‘noclobber’ option is not enabled, the redirection is
attempted even if the file named by WORD exists.
3.6.3 Appending Redirected Output
Of the two forms, the first is preferred. This is semantically
equivalent to
>WORD 2>&1
- When using the second form, WORD may not expand to a number or '-'.
+ When using the second form, WORD may not expand to a number or ‘-’.
If it does, other redirection operators apply (see Duplicating File
Descriptors below) for compatibility reasons.
command.
The format of here-documents is:
- [N]<<[-]WORD
+ [N]<<[−]WORD
HERE-DOCUMENT
DELIMITER
If WORD is unquoted, DELIMITER is WORD itself, all lines of the
here-document are subjected to parameter expansion, command
substitution, and arithmetic expansion, the character sequence
-'\newline' is ignored, and '\' must be used to quote the characters '\',
-'$', and '`'.
+‘\newline’ is ignored, and ‘\’ must be used to quote the characters ‘\’,
+‘$’, and ‘`’.
- If the redirection operator is '<<-', then all leading tab characters
+ If the redirection operator is ‘<<-’, then all leading tab characters
are stripped from input lines and the line containing DELIMITER. This
allows here-documents within shell scripts to be indented in a natural
fashion.
more digits, the file descriptor denoted by N is made to be a copy of
that file descriptor. If the digits in WORD do not specify a file
descriptor open for input, a redirection error occurs. If WORD
-evaluates to '-', file descriptor N is closed. If N is not specified,
+evaluates to ‘-’, file descriptor N is closed. If N is not specified,
the standard input (file descriptor 0) is used.
The operator
is used similarly to duplicate output file descriptors. If N is not
specified, the standard output (file descriptor 1) is used. If the
digits in WORD do not specify a file descriptor open for output, a
-redirection error occurs. If WORD evaluates to '-', file descriptor N
+redirection error occurs. If WORD evaluates to ‘-’, file descriptor N
is closed. As a special case, if N is omitted, and WORD does not expand
-to one or more digits or '-', the standard output and standard error are
+to one or more digits or ‘-’, the standard output and standard error are
redirected as described previously.
3.6.9 Moving File Descriptors
3. Redirections are performed as described above (*note
Redirections::).
- 4. The text after the '=' in each variable assignment undergoes tilde
+ 4. The text after the ‘=’ in each variable assignment undergoes tilde
expansion, parameter expansion, command substitution, arithmetic
expansion, and quote removal before being assigned to the variable.
invoked.
3. If the name is neither a shell function nor a builtin, and contains
- no slashes, Bash searches each element of '$PATH' for a directory
+ no slashes, Bash searches each element of ‘$PATH’ for a directory
containing an executable file by that name. Bash uses a hash table
to remember the full pathnames of executable files to avoid
- multiple 'PATH' searches (see the description of 'hash' in *note
+ multiple ‘PATH’ searches (see the description of ‘hash’ in *note
Bourne Shell Builtins::). A full search of the directories in
- '$PATH' is performed only if the command is not found in the hash
+ ‘$PATH’ is performed only if the command is not found in the hash
table. If the search is unsuccessful, the shell searches for a
- defined shell function named 'command_not_found_handle'. If that
+ defined shell function named ‘command_not_found_handle’. If that
function exists, it is invoked in a separate execution environment
with the original command and the original command's arguments as
its arguments, and the function's exit status becomes the exit
5. If this execution fails because the file is not in executable
format, and the file is not a directory, it is assumed to be a
- "shell script" and the shell executes it as described in *note
+ “shell script” and the shell executes it as described in *note
Shell Scripts::.
6. If the command was not begun asynchronously, the shell waits for
3.7.3 Command Execution Environment
-----------------------------------
-The shell has an "execution environment", which consists of the
+The shell has an “execution environment”, which consists of the
following:
- * open files inherited by the shell at invocation, as modified by
- redirections supplied to the 'exec' builtin
+ • open files inherited by the shell at invocation, as modified by
+ redirections supplied to the ‘exec’ builtin
- * the current working directory as set by 'cd', 'pushd', or 'popd',
+ • the current working directory as set by ‘cd’, ‘pushd’, or ‘popd’,
or inherited by the shell at invocation
- * the file creation mode mask as set by 'umask' or inherited from the
+ • the file creation mode mask as set by ‘umask’ or inherited from the
shell's parent
- * current traps set by 'trap'
+ • current traps set by ‘trap’
- * shell parameters that are set by variable assignment or with 'set'
+ • shell parameters that are set by variable assignment or with ‘set’
or inherited from the shell's parent in the environment
- * shell functions defined during execution or inherited from the
+ • shell functions defined during execution or inherited from the
shell's parent in the environment
- * options enabled at invocation (either by default or with
- command-line arguments) or by 'set'
+ • options enabled at invocation (either by default or with
+ command-line arguments) or by ‘set’
- * options enabled by 'shopt' (*note The Shopt Builtin::)
+ • options enabled by ‘shopt’ (*note The Shopt Builtin::)
- * shell aliases defined with 'alias' (*note Aliases::)
+ • shell aliases defined with ‘alias’ (*note Aliases::)
- * various process IDs, including those of background jobs (*note
- Lists::), the value of '$$', and the value of '$PPID'
+ • various process IDs, including those of background jobs (*note
+ Lists::), the value of ‘$$’, and the value of ‘$PPID’
When a simple command other than a builtin or shell function is to be
executed, it is invoked in a separate execution environment that
consists of the following. Unless otherwise noted, the values are
inherited from the shell.
- * the shell's open files, plus any modifications and additions
+ • the shell's open files, plus any modifications and additions
specified by redirections to the command
- * the current working directory
+ • the current working directory
- * the file creation mode mask
+ • the file creation mode mask
- * shell variables and functions marked for export, along with
+ • shell variables and functions marked for export, along with
variables exported for the command, passed in the environment
(*note Environment::)
- * traps caught by the shell are reset to the values inherited from
+ • traps caught by the shell are reset to the values inherited from
the shell's parent, and traps ignored by the shell are ignored
A command invoked in this separate environment cannot affect the
shell's execution environment.
- A "subshell" is a copy of the shell process.
+ A “subshell” is a copy of the shell process.
Command substitution, commands grouped with parentheses, and
asynchronous commands are invoked in a subshell environment that is a
are also executed in a subshell environment. Changes made to the
subshell environment cannot affect the shell's execution environment.
- Subshells spawned to execute command substitutions inherit the value
-of the '-e' option from the parent shell. When not in POSIX mode, Bash
-clears the '-e' option in such subshells.
+ When the shell is in POSIX mode, subshells spawned to execute command
+substitutions inherit the value of the ‘-e’ option from the parent
+shell. When not in POSIX mode, Bash clears the ‘-e’ option in such
+subshells See the description of the ‘inherit_errexit’ shell option
+(*note Bash Builtins::) for how to control this behavior when not in
+POSIX mode.
- If a command is followed by a '&' and job control is not active, the
-default standard input for the command is the empty file '/dev/null'.
+ If a command is followed by a ‘&’ and job control is not active, the
+default standard input for the command is the empty file ‘/dev/null’.
Otherwise, the invoked command inherits the file descriptors of the
calling shell as modified by redirections.
-----------------
When a program is invoked it is given an array of strings called the
-"environment". This is a list of name-value pairs, of the form
-'name=value'.
+“environment”. This is a list of name-value pairs, of the form
+‘name=value’.
Bash provides several ways to manipulate the environment. On
invocation, the shell scans its own environment and creates a parameter
-for each name found, automatically marking it for 'export' to child
-processes. Executed commands inherit the environment. The 'export' and
-'declare -x' commands allow parameters and functions to be added to and
+for each name found, automatically marking it for ‘export’ to child
+processes. Executed commands inherit the environment. The ‘export’ and
+‘declare -x’ commands allow parameters and functions to be added to and
deleted from the environment. If the value of a parameter in the
environment is modified, the new value becomes part of the environment,
replacing the old. The environment inherited by any executed command
consists of the shell's initial environment, whose values may be
-modified in the shell, less any pairs removed by the 'unset' and 'export
--n' commands, plus any additions via the 'export' and 'declare -x'
+modified in the shell, less any pairs removed by the ‘unset’ and ‘export
+-n’ commands, plus any additions via the ‘export’ and ‘declare -x’
commands.
The environment for any simple command or function may be augmented
*note Shell Parameters::. These assignment statements affect only the
environment seen by that command.
- If the '-k' option is set (*note The Set Builtin::), then all
+ If the ‘-k’ option is set (*note The Set Builtin::), then all
parameter assignments are placed in the environment for a command, not
just those that precede the command name.
- When Bash invokes an external command, the variable '$_' is set to
+ When Bash invokes an external command, the variable ‘$_’ is set to
the full pathname of the command and passed to that command in its
environment.
-----------------
The exit status of an executed command is the value returned by the
-'waitpid' system call or equivalent function. Exit statuses fall
+‘waitpid’ system call or equivalent function. Exit statuses fall
between 0 and 255, though, as explained below, the shell may use values
above 125 specially. Exit statuses from shell builtins and compound
commands are also limited to this range. Under certain circumstances,
-------------
When Bash is interactive, in the absence of any traps, it ignores
-'SIGTERM' (so that 'kill 0' does not kill an interactive shell), and
-'SIGINT' is caught and handled (so that the 'wait' builtin is
-interruptible). When Bash receives a 'SIGINT', it breaks out of any
-executing loops. In all cases, Bash ignores 'SIGQUIT'. If job control
-is in effect (*note Job Control::), Bash ignores 'SIGTTIN', 'SIGTTOU',
-and 'SIGTSTP'.
+‘SIGTERM’ (so that ‘kill 0’ does not kill an interactive shell), and
+‘SIGINT’ is caught and handled (so that the ‘wait’ builtin is
+interruptible). When Bash receives a ‘SIGINT’, it breaks out of any
+executing loops. In all cases, Bash ignores ‘SIGQUIT’. If job control
+is in effect (*note Job Control::), Bash ignores ‘SIGTTIN’, ‘SIGTTOU’,
+and ‘SIGTSTP’.
Non-builtin commands started by Bash have signal handlers set to the
values inherited by the shell from its parent. When job control is not
-in effect, asynchronous commands ignore 'SIGINT' and 'SIGQUIT' in
+in effect, asynchronous commands ignore ‘SIGINT’ and ‘SIGQUIT’ in
addition to these inherited handlers. Commands run as a result of
command substitution ignore the keyboard-generated job control signals
-'SIGTTIN', 'SIGTTOU', and 'SIGTSTP'.
+‘SIGTTIN’, ‘SIGTTOU’, and ‘SIGTSTP’.
- The shell exits by default upon receipt of a 'SIGHUP'. Before
-exiting, an interactive shell resends the 'SIGHUP' to all jobs, running
-or stopped. Stopped jobs are sent 'SIGCONT' to ensure that they receive
-the 'SIGHUP'. To prevent the shell from sending the 'SIGHUP' signal to
+ The shell exits by default upon receipt of a ‘SIGHUP’. Before
+exiting, an interactive shell resends the ‘SIGHUP’ to all jobs, running
+or stopped. Stopped jobs are sent ‘SIGCONT’ to ensure that they receive
+the ‘SIGHUP’. To prevent the shell from sending the ‘SIGHUP’ signal to
a particular job, it should be removed from the jobs table with the
-'disown' builtin (*note Job Control Builtins::) or marked to not receive
-'SIGHUP' using 'disown -h'.
+‘disown’ builtin (*note Job Control Builtins::) or marked to not receive
+‘SIGHUP’ using ‘disown -h’.
- If the 'huponexit' shell option has been set with 'shopt' (*note The
-Shopt Builtin::), Bash sends a 'SIGHUP' to all jobs when an interactive
+ If the ‘huponexit’ shell option has been set with ‘shopt’ (*note The
+Shopt Builtin::), Bash sends a ‘SIGHUP’ to all jobs when an interactive
login shell exits.
If Bash is waiting for a command to complete and receives a signal
for which a trap has been set, the trap will not be executed until the
command completes. When Bash is waiting for an asynchronous command via
-the 'wait' builtin, the reception of a signal for which a trap has been
-set will cause the 'wait' builtin to return immediately with an exit
+the ‘wait’ builtin, the reception of a signal for which a trap has been
+set will cause the ‘wait’ builtin to return immediately with an exit
status greater than 128, immediately after which the trap is executed.
When job control is not enabled, and Bash is waiting for a foreground
command to complete, the shell receives keyboard-generated signals such
-as 'SIGINT' (usually generated by '^C') that users commonly intend to
+as ‘SIGINT’ (usually generated by ‘^C’) that users commonly intend to
send to that command. This happens because the shell and the command
-are in the same process group as the terminal, and '^C' sends 'SIGINT'
+are in the same process group as the terminal, and ‘^C’ sends ‘SIGINT’
to all processes in that process group. See *note Job Control::, for a
more in-depth discussion of process groups.
When Bash is running without job control enabled and receives
-'SIGINT' while waiting for a foreground command, it waits until that
+‘SIGINT’ while waiting for a foreground command, it waits until that
foreground command terminates and then decides what to do about the
-'SIGINT':
+‘SIGINT’:
- 1. If the command terminates due to the 'SIGINT', Bash concludes that
- the user meant to end the entire script, and acts on the 'SIGINT'
- (e.g., by running a 'SIGINT' trap or exiting itself);
+ 1. If the command terminates due to the ‘SIGINT’, Bash concludes that
+ the user meant to end the entire script, and acts on the ‘SIGINT’
+ (e.g., by running a ‘SIGINT’ trap or exiting itself);
- 2. If the pipeline does not terminate due to 'SIGINT', the program
- handled the 'SIGINT' itself and did not treat it as a fatal signal.
- In that case, Bash does not treat 'SIGINT' as a fatal signal,
- either, instead assuming that the 'SIGINT' was used as part of the
- program's normal operation (e.g., 'emacs' uses it to abort editing
+ 2. If the pipeline does not terminate due to ‘SIGINT’, the program
+ handled the ‘SIGINT’ itself and did not treat it as a fatal signal.
+ In that case, Bash does not treat ‘SIGINT’ as a fatal signal,
+ either, instead assuming that the ‘SIGINT’ was used as part of the
+ program's normal operation (e.g., ‘emacs’ uses it to abort editing
commands) or deliberately discarded. However, Bash will run any
- trap set on 'SIGINT', as it does with any other trapped signal it
+ trap set on ‘SIGINT’, as it does with any other trapped signal it
receives while it is waiting for the foreground command to
complete, for compatibility.
A shell script is a text file containing shell commands. When such a
file is used as the first non-option argument when invoking Bash, and
-neither the '-c' nor '-s' option is supplied (*note Invoking Bash::),
+neither the ‘-c’ nor ‘-s’ option is supplied (*note Invoking Bash::),
Bash reads and executes commands from the file, then exits. This mode
of operation creates a non-interactive shell. The shell first searches
for the file in the current directory, and looks in the directories in
-'$PATH' if not found there.
+‘$PATH’ if not found there.
- When Bash runs a shell script, it sets the special parameter '0' to
+ When Bash runs a shell script, it sets the special parameter ‘0’ to
the name of the file, rather than the name of the shell, and the
positional parameters are set to the remaining arguments, if any are
given. If no additional arguments are supplied, the positional
parameters are unset.
- A shell script may be made executable by using the 'chmod' command to
+ A shell script may be made executable by using the ‘chmod’ command to
turn on the execute bit. When Bash finds such a file while searching
-the '$PATH' for a command, it creates a new instance of itself to
+the ‘$PATH’ for a command, it creates a new instance of itself to
execute it. In other words, executing
filename ARGUMENTS
is equivalent to executing
bash filename ARGUMENTS
-if 'filename' is an executable shell script. This subshell
+if ‘filename’ is an executable shell script. This subshell
reinitializes itself, so that the effect is as if a new shell had been
invoked to interpret the script, with the exception that the locations
-of commands remembered by the parent (see the description of 'hash' in
+of commands remembered by the parent (see the description of ‘hash’ in
*note Bourne Shell Builtins::) are retained by the child.
Most versions of Unix make this a part of the operating system's
command execution mechanism. If the first line of a script begins with
-the two characters '#!', the remainder of the line specifies an
+the two characters ‘#!’, the remainder of the line specifies an
interpreter for the program and, depending on the operating system, one
or more optional arguments for that interpreter. Thus, you can specify
-Bash, 'awk', Perl, or some other interpreter and write the rest of the
+Bash, ‘awk’, Perl, or some other interpreter and write the rest of the
script file in that language.
The arguments to the interpreter consist of one or more optional
to a maximum of 32 characters, so it's not portable to assume that using
more than one argument will work.
- Bash scripts often begin with '#! /bin/bash' (assuming that Bash has
-been installed in '/bin'), since this ensures that Bash will be used to
+ Bash scripts often begin with ‘#! /bin/bash’ (assuming that Bash has
+been installed in ‘/bin’), since this ensures that Bash will be used to
interpret the script, even if it is executed under another shell. It's
-a common idiom to use 'env' to find 'bash' even if it's been installed
-in another directory: '#!/usr/bin/env bash' will find the first
-occurrence of 'bash' in '$PATH'.
+a common idiom to use ‘env’ to find ‘bash’ even if it's been installed
+in another directory: ‘#!/usr/bin/env bash’ will find the first
+occurrence of ‘bash’ in ‘$PATH’.
\1f
File: bashref.info, Node: Shell Builtin Commands, Next: Shell Variables, Prev: Basic Shell Features, Up: Top
Many of the builtins have been extended by POSIX or Bash.
Unless otherwise noted, each builtin command documented as accepting
-options preceded by '-' accepts '--' to signify the end of the options.
-The ':', 'true', 'false', and 'test'/'[' builtins do not accept options
-and do not treat '--' specially. The 'exit', 'logout', 'return',
-'break', 'continue', 'let', and 'shift' builtins accept and process
-arguments beginning with '-' without requiring '--'. Other builtins
+options preceded by ‘-’ accepts ‘--’ to signify the end of the options.
+The ‘:’, ‘true’, ‘false’, and ‘test’/‘[’ builtins do not accept options
+and do not treat ‘--’ specially. The ‘exit’, ‘logout’, ‘return’,
+‘break’, ‘continue’, ‘let’, and ‘shift’ builtins accept and process
+arguments beginning with ‘-’ without requiring ‘--’. Other builtins
that accept arguments but are not specified as accepting options
-interpret arguments beginning with '-' as invalid options and require
-'--' to prevent this interpretation.
+interpret arguments beginning with ‘-’ as invalid options and require
+‘--’ to prevent this interpretation.
\1f
File: bashref.info, Node: Bourne Shell Builtins, Next: Bash Builtins, Up: Shell Builtin Commands
Shell. These commands are implemented as specified by the POSIX
standard.
-': (a colon)'
+‘: (a colon)’
: [ARGUMENTS]
Do nothing beyond expanding ARGUMENTS and performing redirections.
The return status is zero.
-'. (a period)'
+‘. (a period)’
. FILENAME [ARGUMENTS]
Read and execute commands from the FILENAME argument in the current
- shell context. If FILENAME does not contain a slash, the 'PATH'
+ shell context. If FILENAME does not contain a slash, the ‘PATH’
variable is used to find FILENAME, but FILENAME does not need to be
executable. When Bash is not in POSIX mode, it searches the
- current directory if FILENAME is not found in '$PATH'. If any
+ current directory if FILENAME is not found in ‘$PATH’. If any
ARGUMENTS are supplied, they become the positional parameters when
FILENAME is executed. Otherwise the positional parameters are
- unchanged. If the '-T' option is enabled, '.' inherits any trap on
- 'DEBUG'; if it is not, any 'DEBUG' trap string is saved and
- restored around the call to '.', and '.' unsets the 'DEBUG' trap
- while it executes. If '-T' is not set, and the sourced file
- changes the 'DEBUG' trap, the new value is retained when '.'
+ unchanged. If the ‘-T’ option is enabled, ‘.’ inherits any trap on
+ ‘DEBUG’; if it is not, any ‘DEBUG’ trap string is saved and
+ restored around the call to ‘.’, and ‘.’ unsets the ‘DEBUG’ trap
+ while it executes. If ‘-T’ is not set, and the sourced file
+ changes the ‘DEBUG’ trap, the new value is retained when ‘.’
completes. The return status is the exit status of the last
command executed, or zero if no commands are executed. If FILENAME
is not found, or cannot be read, the return status is non-zero.
- This builtin is equivalent to 'source'.
+ This builtin is equivalent to ‘source’.
-'break'
+‘break’
break [N]
- Exit from a 'for', 'while', 'until', or 'select' loop. If N is
+ Exit from a ‘for’, ‘while’, ‘until’, or ‘select’ loop. If N is
supplied, the Nth enclosing loop is exited. N must be greater than
or equal to 1. The return status is zero unless N is not greater
than or equal to 1.
-'cd'
+‘cd’
cd [-L|[-P [-e]]] [-@] [DIRECTORY]
Change the current working directory to DIRECTORY. If DIRECTORY is
- not supplied, the value of the 'HOME' shell variable is used. If
- the shell variable 'CDPATH' exists, it is used as a search path:
- each directory name in 'CDPATH' is searched for DIRECTORY, with
- alternative directory names in 'CDPATH' separated by a colon (':').
- If DIRECTORY begins with a slash, 'CDPATH' is not used.
-
- The '-P' option means to not follow symbolic links: symbolic links
- are resolved while 'cd' is traversing DIRECTORY and before
- processing an instance of '..' in DIRECTORY.
-
- By default, or when the '-L' option is supplied, symbolic links in
- DIRECTORY are resolved after 'cd' processes an instance of '..' in
+ not supplied, the value of the ‘HOME’ shell variable is used. If
+ the shell variable ‘CDPATH’ exists, ‘cd’ uses it as a search path:
+ ‘cd’ searches each directory name in ‘CDPATH’ for DIRECTORY, with
+ alternative directory names in ‘CDPATH’ separated by a colon (‘:’).
+ If DIRECTORY begins with a slash, ‘CDPATH’ is not used.
+
+ The ‘-P’ option means to not follow symbolic links: symbolic links
+ are resolved while ‘cd’ is traversing DIRECTORY and before
+ processing an instance of ‘..’ in DIRECTORY.
+
+ By default, or when the ‘-L’ option is supplied, symbolic links in
+ DIRECTORY are resolved after ‘cd’ processes an instance of ‘..’ in
DIRECTORY.
- If '..' appears in DIRECTORY, it is processed by removing the
+ If ‘..’ appears in DIRECTORY, it is processed by removing the
immediately preceding pathname component, back to a slash or the
beginning of DIRECTORY.
- If the '-e' option is supplied with '-P' and the current working
+ If the ‘-e’ option is supplied with ‘-P’ and the current working
directory cannot be successfully determined after a successful
- directory change, 'cd' will return an unsuccessful status.
+ directory change, ‘cd’ will return an unsuccessful status.
- On systems that support it, the '-@' option presents the extended
+ On systems that support it, the ‘-@’ option presents the extended
attributes associated with a file as a directory.
- If DIRECTORY is '-', it is converted to '$OLDPWD' before the
+ If DIRECTORY is ‘-’, it is converted to ‘$OLDPWD’ before the
directory change is attempted.
- If a non-empty directory name from 'CDPATH' is used, or if '-' is
+ If a non-empty directory name from ‘CDPATH’ is used, or if ‘-’ is
the first argument, and the directory change is successful, the
absolute pathname of the new working directory is written to the
standard output.
- If the directory change is successful, 'cd' sets the value of the
- 'PWD' environment variable to the new directory name, and sets the
- 'OLDPWD' environment variable to the value of the current working
+ If the directory change is successful, ‘cd’ sets the value of the
+ ‘PWD’ environment variable to the new directory name, and sets the
+ ‘OLDPWD’ environment variable to the value of the current working
directory before the change.
The return status is zero if the directory is successfully changed,
non-zero otherwise.
-'continue'
+‘continue’
continue [N]
- Resume the next iteration of an enclosing 'for', 'while', 'until',
- or 'select' loop. If N is supplied, the execution of the Nth
+ Resume the next iteration of an enclosing ‘for’, ‘while’, ‘until’,
+ or ‘select’ loop. If N is supplied, the execution of the Nth
enclosing loop is resumed. N must be greater than or equal to 1.
The return status is zero unless N is not greater than or equal to
1.
-'eval'
+‘eval’
eval [ARGUMENTS]
The arguments are concatenated together into a single command,
which is then read and executed, and its exit status returned as
- the exit status of 'eval'. If there are no arguments or only empty
+ the exit status of ‘eval’. If there are no arguments or only empty
arguments, the return status is zero.
-'exec'
+‘exec’
exec [-cl] [-a NAME] [COMMAND [ARGUMENTS]]
If COMMAND is supplied, it replaces the shell without creating a
- new process. If the '-l' option is supplied, the shell places a
+ new process. If the ‘-l’ option is supplied, the shell places a
dash at the beginning of the zeroth argument passed to COMMAND.
- This is what the 'login' program does. The '-c' option causes
- COMMAND to be executed with an empty environment. If '-a' is
+ This is what the ‘login’ program does. The ‘-c’ option causes
+ COMMAND to be executed with an empty environment. If ‘-a’ is
supplied, the shell passes NAME as the zeroth argument to COMMAND.
If COMMAND cannot be executed for some reason, a non-interactive
- shell exits, unless the 'execfail' shell option is enabled. In
+ shell exits, unless the ‘execfail’ shell option is enabled. In
that case, it returns failure. An interactive shell returns
failure if the file cannot be executed. A subshell exits
- unconditionally if 'exec' fails. If no COMMAND is specified,
+ unconditionally if ‘exec’ fails. If no COMMAND is specified,
redirections may be used to affect the current shell environment.
If there are no redirection errors, the return status is zero;
otherwise the return status is non-zero.
-'exit'
+‘exit’
exit [N]
Exit the shell, returning a status of N to the shell's parent. If
N is omitted, the exit status is that of the last command executed.
- Any trap on 'EXIT' is executed before the shell terminates.
+ Any trap on ‘EXIT’ is executed before the shell terminates.
-'export'
+‘export’
export [-fn] [-p] [NAME[=VALUE]]
Mark each NAME to be passed to child processes in the environment.
- If the '-f' option is supplied, the NAMEs refer to shell functions;
- otherwise the names refer to shell variables. The '-n' option
+ If the ‘-f’ option is supplied, the NAMEs refer to shell functions;
+ otherwise the names refer to shell variables. The ‘-n’ option
means to no longer mark each NAME for export. If no NAMEs are
- supplied, or if the '-p' option is given, a list of names of all
- exported variables is displayed. The '-p' option displays output
+ supplied, or if the ‘-p’ option is given, a list of names of all
+ exported variables is displayed. The ‘-p’ option displays output
in a form that may be reused as input. If a variable name is
followed by =VALUE, the value of the variable is set to VALUE.
The return status is zero unless an invalid option is supplied, one
- of the names is not a valid shell variable name, or '-f' is
+ of the names is not a valid shell variable name, or ‘-f’ is
supplied with a name that is not a shell function.
-'false'
+‘false’
false
Does nothing, returns a non-zero status.
-'getopts'
+‘getopts’
getopts OPTSTRING NAME [ARG ...]
- 'getopts' is used by shell scripts to parse positional parameters.
+ ‘getopts’ is used by shell scripts to parse positional parameters.
OPTSTRING contains the option characters to be recognized; if a
character is followed by a colon, the option is expected to have an
argument, which should be separated from it by whitespace. The
- colon (':') and question mark ('?') may not be used as option
- characters. Each time it is invoked, 'getopts' places the next
+ colon (‘:’) and question mark (‘?’) may not be used as option
+ characters. Each time it is invoked, ‘getopts’ places the next
option in the shell variable NAME, initializing NAME if it does not
exist, and the index of the next argument to be processed into the
- variable 'OPTIND'. 'OPTIND' is initialized to 1 each time the
+ variable ‘OPTIND’. ‘OPTIND’ is initialized to 1 each time the
shell or a shell script is invoked. When an option requires an
- argument, 'getopts' places that argument into the variable
- 'OPTARG'. The shell does not reset 'OPTIND' automatically; it must
- be manually reset between multiple calls to 'getopts' within the
+ argument, ‘getopts’ places that argument into the variable
+ ‘OPTARG’. The shell does not reset ‘OPTIND’ automatically; it must
+ be manually reset between multiple calls to ‘getopts’ within the
same shell invocation if a new set of parameters is to be used.
- When the end of options is encountered, 'getopts' exits with a
- return value greater than zero. 'OPTIND' is set to the index of
- the first non-option argument, and NAME is set to '?'.
+ When the end of options is encountered, ‘getopts’ exits with a
+ return value greater than zero. ‘OPTIND’ is set to the index of
+ the first non-option argument, and NAME is set to ‘?’.
- 'getopts' normally parses the positional parameters, but if more
- arguments are supplied as ARG values, 'getopts' parses those
+ ‘getopts’ normally parses the positional parameters, but if more
+ arguments are supplied as ARG values, ‘getopts’ parses those
instead.
- 'getopts' can report errors in two ways. If the first character of
+ ‘getopts’ can report errors in two ways. If the first character of
OPTSTRING is a colon, SILENT error reporting is used. In normal
operation, diagnostic messages are printed when invalid options or
- missing option arguments are encountered. If the variable 'OPTERR'
+ missing option arguments are encountered. If the variable ‘OPTERR’
is set to 0, no error messages will be displayed, even if the first
- character of 'optstring' is not a colon.
+ character of ‘optstring’ is not a colon.
- If an invalid option is seen, 'getopts' places '?' into NAME and,
- if not silent, prints an error message and unsets 'OPTARG'. If
- 'getopts' is silent, the option character found is placed in
- 'OPTARG' and no diagnostic message is printed.
+ If ‘getopts’ detects an invalid option, it places ‘?’ into NAME
+ and, if not silent, prints an error message and unsets ‘OPTARG’.
+ If ‘getopts’ is silent, it assigns the option character found to
+ ‘OPTARG’ and does not print a diagnostic message.
- If a required argument is not found, and 'getopts' is not silent, a
- question mark ('?') is placed in NAME, 'OPTARG' is unset, and a
- diagnostic message is printed. If 'getopts' is silent, then a
- colon (':') is placed in NAME and 'OPTARG' is set to the option
- character found.
+ If a required argument is not found, and ‘getopts’ is not silent,
+ it sets the value of NAME to a question mark (‘?’), unsets
+ ‘OPTARG’, and prints a diagnostic message. If ‘getopts’ is silent,
+ it sets the value of NAME to a colon (‘:’), and sets ‘OPTARG’ to
+ the option character found.
-'hash'
+‘hash’
hash [-r] [-p FILENAME] [-dt] [NAME]
- Each time 'hash' is invoked, it remembers the full filenames of the
+ Each time ‘hash’ is invoked, it remembers the full filenames of the
commands specified as NAME arguments, so they need not be searched
for on subsequent invocations. The commands are found by searching
- through the directories listed in '$PATH'. Any
- previously-remembered filename is discarded. The '-p' option
+ through the directories listed in ‘$PATH’. Any
+ previously-remembered filename is discarded. The ‘-p’ option
inhibits the path search, and FILENAME is used as the location of
- NAME. The '-r' option causes the shell to forget all remembered
- locations. Assigning to the 'PATH' variable also clears all hashed
- filenames. The '-d' option causes the shell to forget the
- remembered location of each NAME. If the '-t' option is supplied,
+ NAME. The ‘-r’ option causes the shell to forget all remembered
+ locations. Assigning to the ‘PATH’ variable also clears all hashed
+ filenames. The ‘-d’ option causes the shell to forget the
+ remembered location of each NAME. If the ‘-t’ option is supplied,
the full pathname to which each NAME corresponds is printed. If
- multiple NAME arguments are supplied with '-t', the NAME is printed
- before the hashed full pathname. The '-l' option causes output to
+ multiple NAME arguments are supplied with ‘-t’, the NAME is printed
+ before the hashed full pathname. The ‘-l’ option causes output to
be displayed in a format that may be reused as input. If no
- arguments are given, or if only '-l' is supplied, information about
- remembered commands is printed. The '-t', '-d', and '-p' options
+ arguments are given, or if only ‘-l’ is supplied, information about
+ remembered commands is printed. The ‘-t’, ‘-d’, and ‘-p’ options
(the options that act on the NAME arguments) are mutually
exclusive. Only one will be active. If more than one is supplied,
- '-t' has higher priority than '-p', and both are higher priority
- than '-d'. The return status is zero unless a NAME is not found or
+ ‘-t’ has higher priority than ‘-p’, and both are higher priority
+ than ‘-d’. The return status is zero unless a NAME is not found or
an invalid option is supplied.
-'pwd'
+‘pwd’
pwd [-LP]
Print the absolute pathname of the current working directory. If
- the '-P' option is supplied, the pathname printed will not contain
- symbolic links. If the '-L' option is supplied, the pathname
+ the ‘-P’ option is supplied, the pathname printed will not contain
+ symbolic links. If the ‘-L’ option is supplied, the pathname
printed may contain symbolic links. The return status is zero
unless an error is encountered while determining the name of the
current directory or an invalid option is supplied.
-'readonly'
+‘readonly’
readonly [-aAf] [-p] [NAME[=VALUE]] ...
Mark each NAME as readonly. The values of these names may not be
- changed by subsequent assignment. If the '-f' option is supplied,
- each NAME refers to a shell function. The '-a' option means each
- NAME refers to an indexed array variable; the '-A' option means
+ changed by subsequent assignment. If the ‘-f’ option is supplied,
+ each NAME refers to a shell function. The ‘-a’ option means each
+ NAME refers to an indexed array variable; the ‘-A’ option means
each NAME refers to an associative array variable. If both options
- are supplied, '-A' takes precedence. If no NAME arguments are
- given, or if the '-p' option is supplied, a list of all readonly
+ are supplied, ‘-A’ takes precedence. If no NAME arguments are
+ given, or if the ‘-p’ option is supplied, a list of all readonly
names is printed. The other options may be used to restrict the
- output to a subset of the set of readonly names. The '-p' option
+ output to a subset of the set of readonly names. The ‘-p’ option
causes output to be displayed in a format that may be reused as
input. If a variable name is followed by =VALUE, the value of the
variable is set to VALUE. The return status is zero unless an
invalid option is supplied, one of the NAME arguments is not a
- valid shell variable or function name, or the '-f' option is
+ valid shell variable or function name, or the ‘-f’ option is
supplied with a name that is not a shell function.
-'return'
+‘return’
return [N]
Cause a shell function to stop executing and return the value N to
its caller. If N is not supplied, the return value is the exit
- status of the last command executed in the function. If 'return'
+ status of the last command executed in the function. If ‘return’
is executed by a trap handler, the last command used to determine
the status is the last command executed before the trap handler.
- If 'return' is executed during a 'DEBUG' trap, the last command
+ If ‘return’ is executed during a ‘DEBUG’ trap, the last command
used to determine the status is the last command executed by the
- trap handler before 'return' was invoked. 'return' may also be
- used to terminate execution of a script being executed with the '.'
- ('source') builtin, returning either N or the exit status of the
+ trap handler before ‘return’ was invoked. ‘return’ may also be
+ used to terminate execution of a script being executed with the ‘.’
+ (‘source’) builtin, returning either N or the exit status of the
last command executed within the script as the exit status of the
script. If N is supplied, the return value is its least
- significant 8 bits. Any command associated with the 'RETURN' trap
+ significant 8 bits. Any command associated with the ‘RETURN’ trap
is executed before execution resumes after the function or script.
- The return status is non-zero if 'return' is supplied a non-numeric
+ The return status is non-zero if ‘return’ is supplied a non-numeric
argument or is used outside a function and not during the execution
- of a script by '.' or 'source'.
+ of a script by ‘.’ or ‘source’.
-'shift'
+‘shift’
shift [N]
Shift the positional parameters to the left by N. The positional
- parameters from N+1 ... '$#' are renamed to '$1' ... '$#'-N.
- Parameters represented by the numbers '$#' down to '$#'-N+1 are
- unset. N must be a non-negative number less than or equal to '$#'.
- If N is zero or greater than '$#', the positional parameters are
+ parameters from N+1 ... ‘$#’ are renamed to ‘$1’ ... ‘$#’-N.
+ Parameters represented by the numbers ‘$#’ down to ‘$#’-N+1 are
+ unset. N must be a non-negative number less than or equal to ‘$#’.
+ If N is zero or greater than ‘$#’, the positional parameters are
not changed. If N is not supplied, it is assumed to be 1. The
- return status is zero unless N is greater than '$#' or less than
+ return status is zero unless N is greater than ‘$#’ or less than
zero, non-zero otherwise.
-'test'
-'['
+‘test’
+‘[’
test EXPR
Evaluate a conditional expression EXPR and return a status of 0
(true) or 1 (false). Each operator and operand must be a separate
argument. Expressions are composed of the primaries described
- below in *note Bash Conditional Expressions::. 'test' does not
+ below in *note Bash Conditional Expressions::. ‘test’ does not
accept any options, nor does it accept and ignore an argument of
- '--' as signifying the end of options.
+ ‘--’ as signifying the end of options.
- When the '[' form is used, the last argument to the command must be
- a ']'.
+ When the ‘[’ form is used, the last argument to the command must be
+ a ‘]’.
Expressions may be combined using the following operators, listed
in decreasing order of precedence. The evaluation depends on the
number of arguments; see below. Operator precedence is used when
there are five or more arguments.
- '! EXPR'
+ ‘! EXPR’
True if EXPR is false.
- '( EXPR )'
+ ‘( EXPR )’
Returns the value of EXPR. This may be used to override the
normal precedence of operators.
- 'EXPR1 -a EXPR2'
+ ‘EXPR1 -a EXPR2’
True if both EXPR1 and EXPR2 are true.
- 'EXPR1 -o EXPR2'
+ ‘EXPR1 -o EXPR2’
True if either EXPR1 or EXPR2 is true.
- The 'test' and '[' builtins evaluate conditional expressions using
+ The ‘test’ and ‘[’ builtins evaluate conditional expressions using
a set of rules based on the number of arguments.
0 arguments
null.
2 arguments
- If the first argument is '!', the expression is true if and
+ If the first argument is ‘!’, the expression is true if and
only if the second argument is null. If the first argument is
one of the unary conditional operators (*note Bash Conditional
Expressions::), the expression is true if the unary test is
operators (*note Bash Conditional Expressions::), the
result of the expression is the result of the binary test
using the first and third arguments as operands. The
- '-a' and '-o' operators are considered binary operators
+ ‘-a’ and ‘-o’ operators are considered binary operators
when there are three arguments.
- 2. If the first argument is '!', the value is the negation
+ 2. If the first argument is ‘!’, the value is the negation
of the two-argument test using the second and third
arguments.
- 3. If the first argument is exactly '(' and the third
- argument is exactly ')', the result is the one-argument
+ 3. If the first argument is exactly ‘(’ and the third
+ argument is exactly ‘)’, the result is the one-argument
test of the second argument.
4. Otherwise, the expression is false.
4 arguments
The following conditions are applied in the order listed.
- 1. If the first argument is '!', the result is the negation
+ 1. If the first argument is ‘!’, the result is the negation
of the three-argument expression composed of the
remaining arguments.
- 2. If the first argument is exactly '(' and the fourth
- argument is exactly ')', the result is the two-argument
+ 2. If the first argument is exactly ‘(’ and the fourth
+ argument is exactly ‘)’, the result is the two-argument
test of the second and third arguments.
3. Otherwise, the expression is parsed and evaluated
according to precedence using the rules listed above.
The expression is parsed and evaluated according to precedence
using the rules listed above.
- If the shell is not in POSIX mode, when used with 'test' or '[',
- the '<' and '>' operators sort lexicographically using ASCII
- ordering. If the shell is in POSIX mode, these operators use the
- current locale.
+ If the shell is in POSIX mode, or if the expression is part of the
+ ‘[[’ command, the ‘<’ and ‘>’ operators sort using the current
+ locale. If the shell is not in POSIX mode, the ‘test’ and ‘[’
+ commands sort lexicographically using ASCII ordering.
The historical operator-precedence parsing with 4 or more arguments
can lead to ambiguities when it encounters strings that look like
- primaries. The POSIX standard has deprecated the '-a' and '-o'
+ primaries. The POSIX standard has deprecated the ‘-a’ and ‘-o’
primaries and enclosing expressions within parentheses. Scripts
should no longer use them. It's much more reliable to restrict
- test invocations to a single primary, and to replace uses of '-a'
- and '-o' with the shell's '&&' and '||' list operators. For
+ test invocations to a single primary, and to replace uses of ‘-a’
+ and ‘-o’ with the shell's ‘&&’ and ‘||’ list operators. For
example, use
test -n string1 && test -n string2
test -n string1 -a -n string2
-'times'
+‘times’
times
Print out the user and system times used by the shell and its
children. The return status is zero.
-'trap'
+‘trap’
trap [-Plp] [ACTION] [SIGSPEC ...]
The ACTION is a command that is read and executed when the shell
receives signal SIGSPEC. If ACTION is absent (and there is a
- single SIGSPEC) or equal to '-', each specified signal's
+ single SIGSPEC) or equal to ‘-’, each specified signal's
disposition is reset to the value it had when the shell was
started. If ACTION is the null string, then the signal specified
by each SIGSPEC is ignored by the shell and commands it invokes.
- If no arguments are supplied, 'trap' prints the actions associated
- with each trapped signal as a set of 'trap' commands that can be
+ If no arguments are supplied, ‘trap’ prints the actions associated
+ with each trapped signal as a set of ‘trap’ commands that can be
reused as shell input to restore the current signal dispositions.
- If ACTION is not present and '-p' has been supplied, 'trap'
+ If ACTION is not present and ‘-p’ has been supplied, ‘trap’
displays the trap commands associated with each SIGSPEC, or, if no
- SIGSPECs are supplied, for all trapped signals, as a set of 'trap'
+ SIGSPECs are supplied, for all trapped signals, as a set of ‘trap’
commands that can be reused as shell input to restore the current
- signal dispositions. The '-P' option behaves similarly, but
+ signal dispositions. The ‘-P’ option behaves similarly, but
displays only the actions associated with each SIGSPEC argument.
- '-P' requires at least one SIGSPEC argument. The '-P' or '-p'
- options to 'trap' may be used in a subshell environment (e.g.,
- command substitution) and, as long as they are used before 'trap'
+ ‘-P’ requires at least one SIGSPEC argument. The ‘-P’ or ‘-p’
+ options to ‘trap’ may be used in a subshell environment (e.g.,
+ command substitution) and, as long as they are used before ‘trap’
is used to change a signal's handling, will display the state of
its parent's traps.
- The '-l' option causes 'trap' to print a list of signal names and
+ The ‘-l’ option causes ‘trap’ to print a list of signal names and
their corresponding numbers. Each SIGSPEC is either a signal name
or a signal number. Signal names are case insensitive and the
- 'SIG' prefix is optional.
+ ‘SIG’ prefix is optional.
- If a SIGSPEC is '0' or 'EXIT', ACTION is executed when the shell
- exits. If a SIGSPEC is 'DEBUG', ACTION is executed before every
- simple command, 'for' command, 'case' command, 'select' command, ((
- arithmetic command, [[ conditional command, arithmetic 'for'
+ If a SIGSPEC is ‘0’ or ‘EXIT’, ACTION is executed when the shell
+ exits. If a SIGSPEC is ‘DEBUG’, ACTION is executed before every
+ simple command, ‘for’ command, ‘case’ command, ‘select’ command, ((
+ arithmetic command, [[ conditional command, arithmetic ‘for’
command, and before the first command executes in a shell function.
- Refer to the description of the 'extdebug' option to the 'shopt'
+ Refer to the description of the ‘extdebug’ option to the ‘shopt’
builtin (*note The Shopt Builtin::) for details of its effect on
- the 'DEBUG' trap. If a SIGSPEC is 'RETURN', ACTION is executed
- each time a shell function or a script executed with the '.' or
- 'source' builtins finishes executing.
+ the ‘DEBUG’ trap. If a SIGSPEC is ‘RETURN’, ACTION is executed
+ each time a shell function or a script executed with the ‘.’ or
+ ‘source’ builtins finishes executing.
- If a SIGSPEC is 'ERR', ACTION is executed whenever a pipeline
+ If a SIGSPEC is ‘ERR’, ACTION is executed whenever a pipeline
(which may consist of a single simple command), a list, or a
compound command returns a non-zero exit status, subject to the
- following conditions. The 'ERR' trap is not executed if the failed
+ following conditions. The ‘ERR’ trap is not executed if the failed
command is part of the command list immediately following an
- 'until' or 'while' keyword, part of the test following the 'if' or
- 'elif' reserved words, part of a command executed in a '&&' or '||'
- list except the command following the final '&&' or '||', any
+ ‘until’ or ‘while’ keyword, part of the test following the ‘if’ or
+ ‘elif’ reserved words, part of a command executed in a ‘&&’ or ‘||’
+ list except the command following the final ‘&&’ or ‘||’, any
command in a pipeline but the last, or if the command's return
- status is being inverted using '!'. These are the same conditions
- obeyed by the 'errexit' ('-e') option.
+ status is being inverted using ‘!’. These are the same conditions
+ obeyed by the ‘errexit’ (‘-e’) option.
Signals ignored upon entry to a non-interactive shell cannot be
trapped or reset. Interactive shells permit trapping signals
The return status is zero unless a SIGSPEC does not specify a valid
signal.
-'true'
+‘true’
true
Does nothing, returns a 0 status.
-'umask'
+‘umask’
umask [-p] [-S] [MODE]
Set the shell process's file creation mask to MODE. If MODE begins
with a digit, it is interpreted as an octal number; if not, it is
interpreted as a symbolic mode mask similar to that accepted by the
- 'chmod' command. If MODE is omitted, the current value of the mask
- is printed. If the '-S' option is supplied without a MODE
- argument, the mask is printed in a symbolic format. If the '-p'
+ ‘chmod’ command. If MODE is omitted, the current value of the mask
+ is printed. If the ‘-S’ option is supplied without a MODE
+ argument, the mask is printed in a symbolic format. If the ‘-p’
option is supplied, and MODE is omitted, the output is in a form
that may be reused as input. The return status is zero if the mode
is successfully changed or if no MODE argument is supplied, and
non-zero otherwise.
Note that when the mode is interpreted as an octal number, each
- number of the umask is subtracted from '7'. Thus, a umask of '022'
- results in permissions of '755'.
+ number of the umask is subtracted from ‘7’. Thus, a umask of ‘022’
+ results in permissions of ‘755’.
-'unset'
+‘unset’
unset [-fnv] [NAME]
- Remove each variable or function NAME. If the '-v' option is
+ Remove each variable or function NAME. If the ‘-v’ option is
given, each NAME refers to a shell variable and that variable is
- removed. If the '-f' option is given, the NAMEs refer to shell
- functions, and the function definition is removed. If the '-n'
- option is supplied, and NAME is a variable with the 'nameref'
+ removed. If the ‘-f’ option is given, the NAMEs refer to shell
+ functions, and the function definition is removed. If the ‘-n’
+ option is supplied, and NAME is a variable with the ‘nameref’
attribute, NAME will be unset rather than the variable it
- references. '-n' has no effect if the '-f' option is supplied. If
+ references. ‘-n’ has no effect if the ‘-f’ option is supplied. If
no options are supplied, each NAME refers to a variable; if there
is no variable by that name, a function with that name, if any, is
unset. Readonly variables and functions may not be unset. Some
extended in Bash. Some of these commands are specified in the POSIX
standard.
-'alias'
+‘alias’
alias [-p] [NAME[=VALUE] ...]
- Without arguments or with the '-p' option, 'alias' prints the list
+ Without arguments or with the ‘-p’ option, ‘alias’ prints the list
of aliases on the standard output in a form that allows them to be
reused as input. If arguments are supplied, an alias is defined
for each NAME whose VALUE is given. If no VALUE is given, the name
and value of the alias is printed. Aliases are described in *note
Aliases::.
-'bind'
+‘bind’
bind [-m KEYMAP] [-lpsvPSVX]
bind [-m KEYMAP] [-q FUNCTION] [-u FUNCTION] [-r KEYSEQ]
bind [-m KEYMAP] -f FILENAME
macro, or set a Readline variable. Each non-option argument is a
command as it would appear in a Readline initialization file (*note
Readline Init File::), but each binding or command must be passed
- as a separate argument; e.g., '"\C-x\C-r":re-read-init-file'.
+ as a separate argument; e.g., ‘"\C-x\C-r":re-read-init-file’.
Options, if supplied, have the following meanings:
- '-m KEYMAP'
+ ‘-m KEYMAP’
Use KEYMAP as the keymap to be affected by the subsequent
- bindings. Acceptable KEYMAP names are 'emacs',
- 'emacs-standard', 'emacs-meta', 'emacs-ctlx', 'vi', 'vi-move',
- 'vi-command', and 'vi-insert'. 'vi' is equivalent to
- 'vi-command' ('vi-move' is also a synonym); 'emacs' is
- equivalent to 'emacs-standard'.
+ bindings. Acceptable KEYMAP names are ‘emacs’,
+ ‘emacs-standard’, ‘emacs-meta’, ‘emacs-ctlx’, ‘vi’, ‘vi-move’,
+ ‘vi-command’, and ‘vi-insert’. ‘vi’ is equivalent to
+ ‘vi-command’ (‘vi-move’ is also a synonym); ‘emacs’ is
+ equivalent to ‘emacs-standard’.
- '-l'
+ ‘-l’
List the names of all Readline functions.
- '-p'
+ ‘-p’
Display Readline function names and bindings in such a way
- that they can be used as an argument to a subsequent 'bind'
+ that they can be used as an argument to a subsequent ‘bind’
command or in a Readline initialization file.
- '-P'
+ ‘-P’
List current Readline function names and bindings.
- '-v'
+ ‘-v’
Display Readline variable names and values in such a way that
- they can be used as an argument to a subsequent 'bind' command
+ they can be used as an argument to a subsequent ‘bind’ command
or in a Readline initialization file.
- '-V'
+ ‘-V’
List current Readline variable names and values.
- '-s'
+ ‘-s’
Display Readline key sequences bound to macros and the strings
they output in such a way that they can be used as an argument
- to a subsequent 'bind' command or in a Readline initialization
+ to a subsequent ‘bind’ command or in a Readline initialization
file.
- '-S'
+ ‘-S’
Display Readline key sequences bound to macros and the strings
they output.
- '-f FILENAME'
+ ‘-f FILENAME’
Read key bindings from FILENAME.
- '-q FUNCTION'
+ ‘-q FUNCTION’
Query about which keys invoke the named FUNCTION.
- '-u FUNCTION'
+ ‘-u FUNCTION’
Unbind all keys bound to the named FUNCTION.
- '-r KEYSEQ'
+ ‘-r KEYSEQ’
Remove any current binding for KEYSEQ.
- '-x KEYSEQ:SHELL-COMMAND'
+ ‘-x KEYSEQ:SHELL-COMMAND’
Cause SHELL-COMMAND to be executed whenever KEYSEQ is entered.
The separator between KEYSEQ and SHELL-COMMAND is either
whitespace or a colon optionally followed by whitespace. If
before saving it. Since the entire key binding expression
must be a single argument, it should be enclosed in quotes.
When SHELL-COMMAND is executed, the shell sets the
- 'READLINE_LINE' variable to the contents of the Readline line
- buffer and the 'READLINE_POINT' and 'READLINE_MARK' variables
+ ‘READLINE_LINE’ variable to the contents of the Readline line
+ buffer and the ‘READLINE_POINT’ and ‘READLINE_MARK’ variables
to the current location of the insertion point and the saved
insertion point (the MARK), respectively. The shell assigns
any numeric argument the user supplied to the
- 'READLINE_ARGUMENT' variable. If there was no argument, that
+ ‘READLINE_ARGUMENT’ variable. If there was no argument, that
variable is not set. If the executed command changes the
- value of any of 'READLINE_LINE', 'READLINE_POINT', or
- 'READLINE_MARK', those new values will be reflected in the
+ value of any of ‘READLINE_LINE’, ‘READLINE_POINT’, or
+ ‘READLINE_MARK’, those new values will be reflected in the
editing state.
- '-X'
+ ‘-X’
List all key sequences bound to shell commands and the
associated commands in a format that can be reused as an
- argument to a subsequent 'bind' command.
+ argument to a subsequent ‘bind’ command.
The return status is zero unless an invalid option is supplied or
an error occurs.
-'builtin'
+‘builtin’
builtin [SHELL-BUILTIN [ARGS]]
Run a shell builtin, passing it ARGS, and return its exit status.
the function. The return status is non-zero if SHELL-BUILTIN is
not a shell builtin command.
-'caller'
+‘caller’
caller [EXPR]
Returns the context of any active subroutine call (a shell function
- or a script executed with the '.' or 'source' builtins).
+ or a script executed with the ‘.’ or ‘source’ builtins).
- Without EXPR, 'caller' displays the line number and source filename
+ Without EXPR, ‘caller’ displays the line number and source filename
of the current subroutine call. If a non-negative integer is
- supplied as EXPR, 'caller' displays the line number, subroutine
+ supplied as EXPR, ‘caller’ displays the line number, subroutine
name, and source file corresponding to that position in the current
execution call stack. This extra information may be used, for
example, to print a stack trace. The current frame is frame 0.
subroutine call or EXPR does not correspond to a valid position in
the call stack.
-'command'
+‘command’
command [-pVv] COMMAND [ARGUMENTS ...]
Runs COMMAND with ARGUMENTS ignoring any shell function named
COMMAND. Only shell builtin commands or commands found by
- searching the 'PATH' are executed. If there is a shell function
- named 'ls', running 'command ls' within the function will execute
- the external command 'ls' instead of calling the function
- recursively. The '-p' option means to use a default value for
- 'PATH' that is guaranteed to find all of the standard utilities.
+ searching the ‘PATH’ are executed. If there is a shell function
+ named ‘ls’, running ‘command ls’ within the function will execute
+ the external command ‘ls’ instead of calling the function
+ recursively. The ‘-p’ option means to use a default value for
+ ‘PATH’ that is guaranteed to find all of the standard utilities.
The return status in this case is 127 if COMMAND cannot be found or
an error occurred, and the exit status of COMMAND otherwise.
- If either the '-V' or '-v' option is supplied, a description of
- COMMAND is printed. The '-v' option causes a single word
+ If either the ‘-V’ or ‘-v’ option is supplied, a description of
+ COMMAND is printed. The ‘-v’ option causes a single word
indicating the command or file name used to invoke COMMAND to be
- displayed; the '-V' option produces a more verbose description. In
+ displayed; the ‘-V’ option produces a more verbose description. In
this case, the return status is zero if COMMAND is found, and
non-zero if not.
-'declare'
+‘declare’
declare [-aAfFgiIlnrtux] [-p] [NAME[=VALUE] ...]
Declare variables and give them attributes. If no NAMEs are given,
then display the values of variables instead.
- The '-p' option will display the attributes and values of each
- NAME. When '-p' is used with NAME arguments, additional options,
- other than '-f' and '-F', are ignored.
+ The ‘-p’ option will display the attributes and values of each
+ NAME. When ‘-p’ is used with NAME arguments, additional options,
+ other than ‘-f’ and ‘-F’, are ignored.
- When '-p' is supplied without NAME arguments, 'declare' will
+ When ‘-p’ is supplied without NAME arguments, ‘declare’ will
display the attributes and values of all variables having the
attributes specified by the additional options. If no other
- options are supplied with '-p', 'declare' will display the
- attributes and values of all shell variables. The '-f' option will
+ options are supplied with ‘-p’, ‘declare’ will display the
+ attributes and values of all shell variables. The ‘-f’ option will
restrict the display to shell functions.
- The '-F' option inhibits the display of function definitions; only
- the function name and attributes are printed. If the 'extdebug'
- shell option is enabled using 'shopt' (*note The Shopt Builtin::),
+ The ‘-F’ option inhibits the display of function definitions; only
+ the function name and attributes are printed. If the ‘extdebug’
+ shell option is enabled using ‘shopt’ (*note The Shopt Builtin::),
the source file name and line number where each NAME is defined are
- displayed as well. '-F' implies '-f'.
+ displayed as well. ‘-F’ implies ‘-f’.
- The '-g' option forces variables to be created or modified at the
- global scope, even when 'declare' is executed in a shell function.
+ The ‘-g’ option forces variables to be created or modified at the
+ global scope, even when ‘declare’ is executed in a shell function.
It is ignored in all other cases.
- The '-I' option causes local variables to inherit the attributes
- (except the 'nameref' attribute) and value of any existing variable
+ The ‘-I’ option causes local variables to inherit the attributes
+ (except the ‘nameref’ attribute) and value of any existing variable
with the same NAME at a surrounding scope. If there is no existing
variable, the local variable is initially unset.
The following options can be used to restrict output to variables
with the specified attributes or to give variables attributes:
- '-a'
+ ‘-a’
Each NAME is an indexed array variable (*note Arrays::).
- '-A'
+ ‘-A’
Each NAME is an associative array variable (*note Arrays::).
- '-f'
+ ‘-f’
Use function names only.
- '-i'
+ ‘-i’
The variable is to be treated as an integer; arithmetic
evaluation (*note Shell Arithmetic::) is performed when the
variable is assigned a value.
- '-l'
+ ‘-l’
When the variable is assigned a value, all upper-case
characters are converted to lower-case. The upper-case
attribute is disabled.
- '-n'
- Give each NAME the 'nameref' attribute, making it a name
+ ‘-n’
+ Give each NAME the ‘nameref’ attribute, making it a name
reference to another variable. That other variable is defined
by the value of NAME. All references, assignments, and
attribute modifications to NAME, except for those using or
- changing the '-n' attribute itself, are performed on the
+ changing the ‘-n’ attribute itself, are performed on the
variable referenced by NAME's value. The nameref attribute
cannot be applied to array variables.
- '-r'
+ ‘-r’
Make NAMEs readonly. These names cannot then be assigned
values by subsequent assignment statements or unset.
- '-t'
- Give each NAME the 'trace' attribute. Traced functions
- inherit the 'DEBUG' and 'RETURN' traps from the calling shell.
+ ‘-t’
+ Give each NAME the ‘trace’ attribute. Traced functions
+ inherit the ‘DEBUG’ and ‘RETURN’ traps from the calling shell.
The trace attribute has no special meaning for variables.
- '-u'
+ ‘-u’
When the variable is assigned a value, all lower-case
characters are converted to upper-case. The lower-case
attribute is disabled.
- '-x'
+ ‘-x’
Mark each NAME for export to subsequent commands via the
environment.
- Using '+' instead of '-' turns off the attribute instead, with the
- exceptions that '+a' and '+A' may not be used to destroy array
- variables and '+r' will not remove the readonly attribute. When
- used in a function, 'declare' makes each NAME local, as with the
- 'local' command, unless the '-g' option is used. If a variable
+ Using ‘+’ instead of ‘-’ turns off the attribute instead, with the
+ exceptions that ‘+a’ and ‘+A’ may not be used to destroy array
+ variables and ‘+r’ will not remove the readonly attribute. When
+ used in a function, ‘declare’ makes each NAME local, as with the
+ ‘local’ command, unless the ‘-g’ option is used. If a variable
name is followed by =VALUE, the value of the variable is set to
VALUE.
- When using '-a' or '-A' and the compound assignment syntax to
+ When using ‘-a’ or ‘-A’ and the compound assignment syntax to
create array variables, additional attributes do not take effect
until subsequent assignments.
The return status is zero unless an invalid option is encountered,
- an attempt is made to define a function using '-f foo=bar', an
+ an attempt is made to define a function using ‘-f foo=bar’, an
attempt is made to assign a value to a readonly variable, an
attempt is made to assign a value to an array variable without
using the compound assignment syntax (*note Arrays::), one of the
NAMEs is not a valid shell variable name, an attempt is made to
turn off readonly status for a readonly variable, an attempt is
made to turn off array status for an array variable, or an attempt
- is made to display a non-existent function with '-f'.
+ is made to display a non-existent function with ‘-f’.
-'echo'
+‘echo’
echo [-neE] [ARG ...]
Output the ARGs, separated by spaces, terminated with a newline.
- The return status is 0 unless a write error occurs. If '-n' is
- specified, the trailing newline is suppressed. If the '-e' option
+ The return status is 0 unless a write error occurs. If ‘-n’ is
+ specified, the trailing newline is suppressed. If the ‘-e’ option
is given, interpretation of the following backslash-escaped
- characters is enabled. The '-E' option disables the interpretation
+ characters is enabled. The ‘-E’ option disables the interpretation
of these escape characters, even on systems where they are
- interpreted by default. The 'xpg_echo' shell option may be used to
- dynamically determine whether or not 'echo' interprets any options
- and expands these escape characters by default. 'echo' does not
- interpret '--' to mean the end of options.
+ interpreted by default. The ‘xpg_echo’ shell option may be used to
+ dynamically determine whether or not ‘echo’ interprets any options
+ and expands these escape characters by default. ‘echo’ does not
+ interpret ‘--’ to mean the end of options.
- 'echo' interprets the following escape sequences:
- '\a'
+ ‘echo’ interprets the following escape sequences:
+ ‘\a’
alert (bell)
- '\b'
+ ‘\b’
backspace
- '\c'
+ ‘\c’
suppress further output
- '\e'
- '\E'
+ ‘\e’
+ ‘\E’
escape
- '\f'
+ ‘\f’
form feed
- '\n'
+ ‘\n’
new line
- '\r'
+ ‘\r’
carriage return
- '\t'
+ ‘\t’
horizontal tab
- '\v'
+ ‘\v’
vertical tab
- '\\'
+ ‘\\’
backslash
- '\0NNN'
+ ‘\0NNN’
the eight-bit character whose value is the octal value NNN
(zero to three octal digits)
- '\xHH'
+ ‘\xHH’
the eight-bit character whose value is the hexadecimal value
HH (one or two hex digits)
- '\uHHHH'
+ ‘\uHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHH (one to four hex digits)
- '\UHHHHHHHH'
+ ‘\UHHHHHHHH’
the Unicode (ISO/IEC 10646) character whose value is the
hexadecimal value HHHHHHHH (one to eight hex digits)
-'enable'
+‘enable’
enable [-a] [-dnps] [-f FILENAME] [NAME ...]
Enable and disable builtin shell commands. Disabling a builtin
allows a disk command which has the same name as a shell builtin to
be executed without specifying a full pathname, even though the
- shell normally searches for builtins before disk commands. If '-n'
+ shell normally searches for builtins before disk commands. If ‘-n’
is used, the NAMEs become disabled. Otherwise NAMEs are enabled.
- For example, to use the 'test' binary found via '$PATH' instead of
- the shell builtin version, type 'enable -n test'.
+ For example, to use the ‘test’ binary found via ‘$PATH’ instead of
+ the shell builtin version, type ‘enable -n test’.
- If the '-p' option is supplied, or no NAME arguments appear, a list
+ If the ‘-p’ option is supplied, or no NAME arguments appear, a list
of shell builtins is printed. With no other arguments, the list
- consists of all enabled shell builtins. The '-a' option means to
+ consists of all enabled shell builtins. The ‘-a’ option means to
list each builtin with an indication of whether or not it is
enabled.
- The '-f' option means to load the new builtin command NAME from
+ The ‘-f’ option means to load the new builtin command NAME from
shared object FILENAME, on systems that support dynamic loading.
- Bash will use the value of the 'BASH_LOADABLES_PATH' variable as a
+ Bash will use the value of the ‘BASH_LOADABLES_PATH’ variable as a
colon-separated list of directories in which to search for
FILENAME, if FILENAME does not contain a slash. The default is
system-dependent, and may include "." to force a search of the
- current directory. The '-d' option will delete a builtin loaded
- with '-f'.
+ current directory. The ‘-d’ option will delete a builtin loaded
+ with ‘-f’.
If there are no options, a list of the shell builtins is displayed.
- The '-s' option restricts 'enable' to the POSIX special builtins.
- If '-s' is used with '-f', the new builtin becomes a special
+ The ‘-s’ option restricts ‘enable’ to the POSIX special builtins.
+ If ‘-s’ is used with ‘-f’, the new builtin becomes a special
builtin (*note Special Builtins::).
If no options are supplied and a NAME is not a shell builtin,
- 'enable' will attempt to load NAME from a shared object named NAME,
- as if the command were 'enable -f NAME NAME'.
+ ‘enable’ will attempt to load NAME from a shared object named NAME,
+ as if the command were ‘enable -f NAME NAME’.
The return status is zero unless a NAME is not a shell builtin or
there is an error loading a new builtin from a shared object.
-'help'
+‘help’
help [-dms] [PATTERN]
Display helpful information about builtin commands. If PATTERN is
- specified, 'help' gives detailed help on all commands matching
+ specified, ‘help’ gives detailed help on all commands matching
PATTERN, otherwise a list of the builtins is printed.
Options, if supplied, have the following meanings:
- '-d'
+ ‘-d’
Display a short description of each PATTERN
- '-m'
+ ‘-m’
Display the description of each PATTERN in a manpage-like
format
- '-s'
+ ‘-s’
Display only a short usage synopsis for each PATTERN
The return status is zero unless no command matches PATTERN.
-'let'
+‘let’
let EXPRESSION [EXPRESSION ...]
- The 'let' builtin allows arithmetic to be performed on shell
+ The ‘let’ builtin allows arithmetic to be performed on shell
variables. Each EXPRESSION is evaluated according to the rules
given below in *note Shell Arithmetic::. If the last EXPRESSION
- evaluates to 0, 'let' returns 1; otherwise 0 is returned.
+ evaluates to 0, ‘let’ returns 1; otherwise 0 is returned.
-'local'
+‘local’
local [OPTION] NAME[=VALUE] ...
For each argument, a local variable named NAME is created, and
assigned VALUE. The OPTION can be any of the options accepted by
- 'declare'. 'local' can only be used within a function; it makes
+ ‘declare’. ‘local’ can only be used within a function; it makes
the variable NAME have a visible scope restricted to that function
- and its children. If NAME is '-', the set of shell options is made
- local to the function in which 'local' is invoked: shell options
- changed using the 'set' builtin inside the function after the call
- to 'local' are restored to their original values when the function
- returns. The restore is effected as if a series of 'set' commands
+ and its children. If NAME is ‘-’, the set of shell options is made
+ local to the function in which ‘local’ is invoked: shell options
+ changed using the ‘set’ builtin inside the function after the call
+ to ‘local’ are restored to their original values when the function
+ returns. The restore is effected as if a series of ‘set’ commands
were executed to restore the values that were in place before the
- function. The return status is zero unless 'local' is used outside
+ function. The return status is zero unless ‘local’ is used outside
a function, an invalid NAME is supplied, or NAME is a readonly
variable.
-'logout'
+‘logout’
logout [N]
Exit a login shell, returning a status of N to the shell's parent.
-'mapfile'
+‘mapfile’
mapfile [-d DELIM] [-n COUNT] [-O ORIGIN] [-s COUNT]
[-t] [-u FD] [-C CALLBACK] [-c QUANTUM] [ARRAY]
Read lines from the standard input into the indexed array variable
- ARRAY, or from file descriptor FD if the '-u' option is supplied.
- The variable 'MAPFILE' is the default ARRAY. Options, if supplied,
+ ARRAY, or from file descriptor FD if the ‘-u’ option is supplied.
+ The variable ‘MAPFILE’ is the default ARRAY. Options, if supplied,
have the following meanings:
- '-d'
+ ‘-d’
The first character of DELIM is used to terminate each input
line, rather than newline. If DELIM is the empty string,
- 'mapfile' will terminate a line when it reads a NUL character.
- '-n'
+ ‘mapfile’ will terminate a line when it reads a NUL character.
+ ‘-n’
Copy at most COUNT lines. If COUNT is 0, all lines are
copied.
- '-O'
+ ‘-O’
Begin assigning to ARRAY at index ORIGIN. The default index
is 0.
- '-s'
+ ‘-s’
Discard the first COUNT lines read.
- '-t'
+ ‘-t’
Remove a trailing DELIM (default newline) from each line read.
- '-u'
+ ‘-u’
Read lines from file descriptor FD instead of the standard
input.
- '-C'
- Evaluate CALLBACK each time QUANTUM lines are read. The '-c'
+ ‘-C’
+ Evaluate CALLBACK each time QUANTUM lines are read. The ‘-c’
option specifies QUANTUM.
- '-c'
+ ‘-c’
Specify the number of lines read between each call to
CALLBACK.
- If '-C' is specified without '-c', the default quantum is 5000.
+ If ‘-C’ is specified without ‘-c’, the default quantum is 5000.
When CALLBACK is evaluated, it is supplied the index of the next
array element to be assigned and the line to be assigned to that
element as additional arguments. CALLBACK is evaluated after the
line is read but before the array element is assigned.
- If not supplied with an explicit origin, 'mapfile' will clear ARRAY
+ If not supplied with an explicit origin, ‘mapfile’ will clear ARRAY
before assigning to it.
- 'mapfile' returns successfully unless an invalid option or option
+ ‘mapfile’ returns successfully unless an invalid option or option
argument is supplied, ARRAY is invalid or unassignable, or ARRAY is
not an indexed array.
-'printf'
+‘printf’
printf [-v VAR] FORMAT [ARGUMENTS]
Write the formatted ARGUMENTS to the standard output under the
- control of the FORMAT. The '-v' option causes the output to be
+ control of the FORMAT. The ‘-v’ option causes the output to be
assigned to the variable VAR rather than being printed to the
standard output.
output, character escape sequences, which are converted and copied
to the standard output, and format specifications, each of which
causes printing of the next successive ARGUMENT. In addition to
- the standard 'printf(3)' format characters 'csndiouxXeEfFgGaA',
- 'printf' interprets the following additional format specifiers:
+ the standard ‘printf(3)’ format characters ‘csndiouxXeEfFgGaA’,
+ ‘printf’ interprets the following additional format specifiers:
- '%b'
- Causes 'printf' to expand backslash escape sequences in the
- corresponding ARGUMENT in the same way as 'echo -e' (*note
+ ‘%b’
+ Causes ‘printf’ to expand backslash escape sequences in the
+ corresponding ARGUMENT in the same way as ‘echo -e’ (*note
Bash Builtins::).
- '%q'
- Causes 'printf' to output the corresponding ARGUMENT in a
- format that can be reused as shell input. '%q' and '%Q'P use
+ ‘%q’
+ Causes ‘printf’ to output the corresponding ARGUMENT in a
+ format that can be reused as shell input. ‘%q’ and ‘%Q’P use
the ANSI-C quoting style (*note ANSI-C Quoting::) if any
characters in the argument string require it, and backslash
- quoting otherwise. If the format string uses the 'printf'
+ quoting otherwise. If the format string uses the ‘printf’
ALTERNATE FORM, these two formats quote the argument string
using single quotes.
- '%Q'
- like '%q', but applies any supplied precision to the ARGUMENT
+ ‘%Q’
+ like ‘%q’, but applies any supplied precision to the ARGUMENT
before quoting it.
- '%(DATEFMT)T'
- Causes 'printf' to output the date-time string resulting from
- using DATEFMT as a format string for 'strftime'(3). The
+ ‘%(DATEFMT)T’
+ Causes ‘printf’ to output the date-time string resulting from
+ using DATEFMT as a format string for ‘strftime’(3). The
corresponding ARGUMENT is an integer representing the number
of seconds since the epoch. Two special argument values may
be used: -1 represents the current time, and -2 represents the
time the shell was invoked. If no argument is specified,
conversion behaves as if -1 had been given. This is an
- exception to the usual 'printf' behavior.
+ exception to the usual ‘printf’ behavior.
The %b, %q, and %T format specifiers all use the field width and
precision arguments from the format specification and write that
success, non-zero if an invalid option is supplied or a write or
assignment error occurs.
-'read'
+‘read’
read [-Eers] [-a ANAME] [-d DELIM] [-i TEXT] [-n NCHARS]
[-N NCHARS] [-p PROMPT] [-t TIMEOUT] [-u FD] [NAME ...]
One line is read from the standard input, or from the file
- descriptor FD supplied as an argument to the '-u' option, split
+ descriptor FD supplied as an argument to the ‘-u’ option, split
into words as described above in *note Word Splitting::, and the
first word is assigned to the first NAME, the second word to the
second NAME, and so on. If there are more words than names, the
remaining words and their intervening delimiters are assigned to
the last NAME. If there are fewer words read from the input stream
than names, the remaining names are assigned empty values. The
- characters in the value of the 'IFS' variable are used to split the
+ characters in the value of the ‘IFS’ variable are used to split the
line into words using the same rules the shell uses for expansion
(described above in *note Word Splitting::). The backslash
- character '\' may be used to remove any special meaning for the
+ character ‘\’ may be used to remove any special meaning for the
next character read and for line continuation.
Options, if supplied, have the following meanings:
- '-a ANAME'
+ ‘-a ANAME’
The words are assigned to sequential indices of the array
variable ANAME, starting at 0. All elements are removed from
ANAME before the assignment. Other NAME arguments are
ignored.
- '-d DELIM'
+ ‘-d DELIM’
The first character of DELIM is used to terminate the input
line, rather than newline. If DELIM is the empty string,
- 'read' will terminate a line when it reads a NUL character.
+ ‘read’ will terminate a line when it reads a NUL character.
- '-e'
+ ‘-e’
Readline (*note Command Line Editing::) is used to obtain the
line. Readline uses the current (or default, if line editing
was not previously active) editing settings, but uses
Readline's default filename completion.
- '-E'
+ ‘-E’
Readline (*note Command Line Editing::) is used to obtain the
line. Readline uses the current (or default, if line editing
was not previously active) editing settings, but uses Bash's
default completion, including programmable completion.
- '-i TEXT'
+ ‘-i TEXT’
If Readline is being used to read the line, TEXT is placed
into the editing buffer before editing begins.
- '-n NCHARS'
- 'read' returns after reading NCHARS characters rather than
+ ‘-n NCHARS’
+ ‘read’ returns after reading NCHARS characters rather than
waiting for a complete line of input, but honors a delimiter
if fewer than NCHARS characters are read before the delimiter.
- '-N NCHARS'
- 'read' returns after reading exactly NCHARS characters rather
+ ‘-N NCHARS’
+ ‘read’ returns after reading exactly NCHARS characters rather
than waiting for a complete line of input, unless EOF is
- encountered or 'read' times out. Delimiter characters
+ encountered or ‘read’ times out. Delimiter characters
encountered in the input are not treated specially and do not
- cause 'read' to return until NCHARS characters are read. The
- result is not split on the characters in 'IFS'; the intent is
+ cause ‘read’ to return until NCHARS characters are read. The
+ result is not split on the characters in ‘IFS’; the intent is
that the variable is assigned exactly the characters read
- (with the exception of backslash; see the '-r' option below).
+ (with the exception of backslash; see the ‘-r’ option below).
- '-p PROMPT'
+ ‘-p PROMPT’
Display PROMPT, without a trailing newline, before attempting
to read any input. The prompt is displayed only if input is
coming from a terminal.
- '-r'
+ ‘-r’
If this option is given, backslash does not act as an escape
character. The backslash is considered to be part of the
line. In particular, a backslash-newline pair may not then be
used as a line continuation.
- '-s'
+ ‘-s’
Silent mode. If input is coming from a terminal, characters
are not echoed.
- '-t TIMEOUT'
- Cause 'read' to time out and return failure if a complete line
+ ‘-t TIMEOUT’
+ Cause ‘read’ to time out and return failure if a complete line
of input (or a specified number of characters) is not read
within TIMEOUT seconds. TIMEOUT may be a decimal number with
a fractional portion following the decimal point. This option
- is only effective if 'read' is reading input from a terminal,
+ is only effective if ‘read’ is reading input from a terminal,
pipe, or other special file; it has no effect when reading
- from regular files. If 'read' times out, 'read' saves any
+ from regular files. If ‘read’ times out, ‘read’ saves any
partial input read into the specified variable NAME. If
- TIMEOUT is 0, 'read' returns immediately, without trying to
+ TIMEOUT is 0, ‘read’ returns immediately, without trying to
read any data. The exit status is 0 if input is available on
the specified file descriptor, or the read will return EOF,
non-zero otherwise. The exit status is greater than 128 if
the timeout is exceeded.
- '-u FD'
+ ‘-u FD’
Read input from file descriptor FD.
+ Other than the case where DELIM is the empty string, ‘read’ ignores
+ any NUL characters in the input.
+
If no NAMEs are supplied, the line read, without the ending
delimiter but otherwise unmodified, is assigned to the variable
- 'REPLY'. The exit status is zero, unless end-of-file is
- encountered, 'read' times out (in which case the status is greater
+ ‘REPLY’. The exit status is zero, unless end-of-file is
+ encountered, ‘read’ times out (in which case the status is greater
than 128), a variable assignment error (such as assigning to a
readonly variable) occurs, or an invalid file descriptor is
- supplied as the argument to '-u'.
+ supplied as the argument to ‘-u’.
-'readarray'
+‘readarray’
readarray [-d DELIM] [-n COUNT] [-O ORIGIN] [-s COUNT]
[-t] [-u FD] [-C CALLBACK] [-c QUANTUM] [ARRAY]
Read lines from the standard input into the indexed array variable
- ARRAY, or from file descriptor FD if the '-u' option is supplied.
+ ARRAY, or from file descriptor FD if the ‘-u’ option is supplied.
- A synonym for 'mapfile'.
+ A synonym for ‘mapfile’.
-'source'
+‘source’
source FILENAME
- A synonym for '.' (*note Bourne Shell Builtins::).
+ A synonym for ‘.’ (*note Bourne Shell Builtins::).
-'type'
+‘type’
type [-afptP] [NAME ...]
For each NAME, indicate how it would be interpreted if used as a
command name.
- If the '-t' option is used, 'type' prints a single word which is
- one of 'alias', 'keyword', 'function', 'builtin', or 'file', if
+ If the ‘-t’ option is used, ‘type’ prints a single word which is
+ one of ‘alias’, ‘keyword’, ‘function’, ‘builtin’, or ‘file’, if
NAME is an alias, shell reserved word, shell function, shell
builtin, or executable disk file, respectively. If the NAME is not
- found, then nothing is printed, and 'type' returns a failure
+ found, then nothing is printed, and ‘type’ returns a failure
status.
- If the '-p' option is used, 'type' either returns the name of the
- executable file that would be found by searching '$PATH', or
- nothing if '-t' would not return 'file'.
+ If the ‘-p’ option is used, ‘type’ either returns the name of the
+ executable file that would be found by searching ‘$PATH’, or
+ nothing if ‘-t’ would not return ‘file’.
- The '-P' option forces a path search for each NAME, even if '-t'
- would not return 'file'.
+ The ‘-P’ option forces a path search for each NAME, even if ‘-t’
+ would not return ‘file’.
- If a NAME is present in the table of hashed commands, options '-p'
- and '-P' print the hashed value, which is not necessarily the file
- that appears first in '$PATH'.
+ If a NAME is present in the table of hashed commands, options ‘-p’
+ and ‘-P’ print the hashed value, which is not necessarily the file
+ that appears first in ‘$PATH’.
- If the '-a' option is used, 'type' returns all of the places that
+ If the ‘-a’ option is used, ‘type’ returns all of the places that
contain a command named NAME. This includes aliases, reserved
- words, functions, and builtins, but the path search options ('-p'
- and '-P') can be supplied to restrict the output to executable
- files. If '-a' is supplied with '-p', 'type' does not look in the
- table of hashed commands, and only performs a 'PATH' search for
+ words, functions, and builtins, but the path search options (‘-p’
+ and ‘-P’) can be supplied to restrict the output to executable
+ files. If ‘-a’ is supplied with ‘-p’, ‘type’ does not look in the
+ table of hashed commands, and only performs a ‘PATH’ search for
NAME.
- If the '-f' option is used, 'type' does not attempt to find shell
- functions, as with the 'command' builtin.
+ If the ‘-f’ option is used, ‘type’ does not attempt to find shell
+ functions, as with the ‘command’ builtin.
The return status is zero if all of the NAMEs are found, non-zero
if any are not found.
-'typeset'
+‘typeset’
typeset [-afFgrxilnrtux] [-p] [NAME[=VALUE] ...]
- The 'typeset' command is supplied for compatibility with the Korn
- shell. It is a synonym for the 'declare' builtin command.
+ The ‘typeset’ command is supplied for compatibility with the Korn
+ shell. It is a synonym for the ‘declare’ builtin command.
-'ulimit'
+‘ulimit’
ulimit [-HS] -a
ulimit [-HS] [-bcdefiklmnpqrstuvxPRT] [LIMIT]
- 'ulimit' provides control over the resources available to processes
+ ‘ulimit’ provides control over the resources available to processes
started by the shell, on systems that allow such control. If an
option is given, it is interpreted as follows:
- '-S'
+ ‘-S’
Change and report the soft limit associated with a resource.
- '-H'
+ ‘-H’
Change and report the hard limit associated with a resource.
- '-a'
+ ‘-a’
All current limits are reported; no limits are set.
- '-b'
+ ‘-b’
The maximum socket buffer size.
- '-c'
+ ‘-c’
The maximum size of core files created.
- '-d'
+ ‘-d’
The maximum size of a process's data segment.
- '-e'
+ ‘-e’
The maximum scheduling priority ("nice").
- '-f'
+ ‘-f’
The maximum size of files written by the shell and its
children.
- '-i'
+ ‘-i’
The maximum number of pending signals.
- '-k'
+ ‘-k’
The maximum number of kqueues that may be allocated.
- '-l'
+ ‘-l’
The maximum size that may be locked into memory.
- '-m'
+ ‘-m’
The maximum resident set size (many systems do not honor this
limit).
- '-n'
+ ‘-n’
The maximum number of open file descriptors (most systems do
not allow this value to be set).
- '-p'
+ ‘-p’
The pipe buffer size.
- '-q'
+ ‘-q’
The maximum number of bytes in POSIX message queues.
- '-r'
+ ‘-r’
The maximum real-time scheduling priority.
- '-s'
+ ‘-s’
The maximum stack size.
- '-t'
+ ‘-t’
The maximum amount of cpu time in seconds.
- '-u'
+ ‘-u’
The maximum number of processes available to a single user.
- '-v'
+ ‘-v’
The maximum amount of virtual memory available to the shell,
and, on some systems, to its children.
- '-x'
+ ‘-x’
The maximum number of file locks.
- '-P'
+ ‘-P’
The maximum number of pseudoterminals.
- '-R'
+ ‘-R’
The maximum time a real-time process can run before blocking,
in microseconds.
- '-T'
+ ‘-T’
The maximum number of threads.
- If LIMIT is given, and the '-a' option is not used, LIMIT is the
+ If LIMIT is given, and the ‘-a’ option is not used, LIMIT is the
new value of the specified resource. The special LIMIT values
- 'hard', 'soft', and 'unlimited' stand for the current hard limit,
+ ‘hard’, ‘soft’, and ‘unlimited’ stand for the current hard limit,
the current soft limit, and no limit, respectively. A hard limit
cannot be increased by a non-root user once it is set; a soft limit
may be increased up to the value of the hard limit. Otherwise, the
current value of the soft limit for the specified resource is
- printed, unless the '-H' option is supplied. When more than one
+ printed, unless the ‘-H’ option is supplied. When more than one
resource is specified, the limit name and unit, if appropriate, are
- printed before the value. When setting new limits, if neither '-H'
- nor '-S' is supplied, both the hard and soft limits are set. If no
- option is given, then '-f' is assumed. Values are in 1024-byte
- increments, except for '-t', which is in seconds; '-R', which is in
- microseconds; '-p', which is in units of 512-byte blocks; '-P',
- '-T', '-b', '-k', '-n' and '-u', which are unscaled values; and,
- when in POSIX Mode (*note Bash POSIX Mode::), '-c' and '-f', which
+ printed before the value. When setting new limits, if neither ‘-H’
+ nor ‘-S’ is supplied, both the hard and soft limits are set. If no
+ option is given, then ‘-f’ is assumed. Values are in 1024-byte
+ increments, except for ‘-t’, which is in seconds; ‘-R’, which is in
+ microseconds; ‘-p’, which is in units of 512-byte blocks; ‘-P’,
+ ‘-T’, ‘-b’, ‘-k’, ‘-n’ and ‘-u’, which are unscaled values; and,
+ when in POSIX Mode (*note Bash POSIX Mode::), ‘-c’ and ‘-f’, which
are in 512-byte increments.
The return status is zero unless an invalid option or argument is
supplied, or an error occurs while setting a new limit.
-'unalias'
+‘unalias’
unalias [-a] [NAME ... ]
- Remove each NAME from the list of aliases. If '-a' is supplied,
+ Remove each NAME from the list of aliases. If ‘-a’ is supplied,
all aliases are removed. Aliases are described in *note Aliases::.
\1f
4.3.1 The Set Builtin
---------------------
-This builtin is so complicated that it deserves its own section. 'set'
+This builtin is so complicated that it deserves its own section. ‘set’
allows you to change the values of shell options and set the positional
parameters, or to display the names and values of shell variables.
-'set'
+‘set’
set [-abefhkmnptuvxBCEHPT] [-o OPTION-NAME] [--] [-] [ARGUMENT ...]
set [+abefhkmnptuvxBCEHPT] [+o OPTION-NAME] [--] [-] [ARGUMENT ...]
set -o
set +o
- If no options or arguments are supplied, 'set' displays the names
+ If no options or arguments are supplied, ‘set’ displays the names
and values of all shell variables and functions, sorted according
to the current locale, in a format that may be reused as input for
setting or resetting the currently-set variables. Read-only
When options are supplied, they set or unset shell attributes.
Options, if specified, have the following meanings:
- '-a'
+ ‘-a’
Each variable or function that is created or modified is given
the export attribute and marked for export to the environment
of subsequent commands.
- '-b'
+ ‘-b’
Cause the status of terminated background jobs to be reported
immediately, rather than before printing the next primary
prompt.
- '-e'
+ ‘-e’
Exit immediately if a pipeline (*note Pipelines::), which may
consist of a single simple command (*note Simple Commands::),
a list (*note Lists::), or a compound command (*note Compound
Commands::) returns a non-zero status. The shell does not
exit if the command that fails is part of the command list
- immediately following a 'while' or 'until' keyword, part of
- the test in an 'if' statement, part of any command executed in
- a '&&' or '||' list except the command following the final
- '&&' or '||', any command in a pipeline but the last, or if
- the command's return status is being inverted with '!'. If a
+ immediately following a ‘while’ or ‘until’ keyword, part of
+ the test in an ‘if’ statement, part of any command executed in
+ a ‘&&’ or ‘||’ list except the command following the final
+ ‘&&’ or ‘||’, any command in a pipeline but the last, or if
+ the command's return status is being inverted with ‘!’. If a
compound command other than a subshell returns a non-zero
- status because a command failed while '-e' was being ignored,
- the shell does not exit. A trap on 'ERR', if set, is executed
+ status because a command failed while ‘-e’ was being ignored,
+ the shell does not exit. A trap on ‘ERR’, if set, is executed
before the shell exits.
This option applies to the shell environment and each subshell
executing all the commands in the subshell.
If a compound command or shell function executes in a context
- where '-e' is being ignored, none of the commands executed
+ where ‘-e’ is being ignored, none of the commands executed
within the compound command or function body will be affected
- by the '-e' setting, even if '-e' is set and a command returns
+ by the ‘-e’ setting, even if ‘-e’ is set and a command returns
a failure status. If a compound command or shell function
- sets '-e' while executing in a context where '-e' is ignored,
+ sets ‘-e’ while executing in a context where ‘-e’ is ignored,
that setting will not have any effect until the compound
command or the command containing the function call completes.
- '-f'
+ ‘-f’
Disable filename expansion (globbing).
- '-h'
+ ‘-h’
Locate and remember (hash) commands as they are looked up for
execution. This option is enabled by default.
- '-k'
+ ‘-k’
All arguments in the form of assignment statements are placed
in the environment for a command, not just those that precede
the command name.
- '-m'
+ ‘-m’
Job control is enabled (*note Job Control::). All processes
run in a separate process group. When a background job
completes, the shell prints a line containing its exit status.
- '-n'
+ ‘-n’
Read commands but do not execute them. This may be used to
check a script for syntax errors. This option is ignored by
interactive shells.
- '-o OPTION-NAME'
+ ‘-o OPTION-NAME’
- Set the option corresponding to OPTION-NAME. If '-o' is
- supplied with no OPTION-NAME, 'set' prints the current shell
- options settings. If '+o' is supplied with no OPTION-NAME,
- 'set' prints a series of 'set' commands to recreate the
+ Set the option corresponding to OPTION-NAME. If ‘-o’ is
+ supplied with no OPTION-NAME, ‘set’ prints the current shell
+ options settings. If ‘+o’ is supplied with no OPTION-NAME,
+ ‘set’ prints a series of ‘set’ commands to recreate the
current option settings on the standard output. Valid option
names are:
- 'allexport'
- Same as '-a'.
+ ‘allexport’
+ Same as ‘-a’.
- 'braceexpand'
- Same as '-B'.
+ ‘braceexpand’
+ Same as ‘-B’.
- 'emacs'
- Use an 'emacs'-style line editing interface (*note
+ ‘emacs’
+ Use an ‘emacs’-style line editing interface (*note
Command Line Editing::). This also affects the editing
- interface used for 'read -e'.
+ interface used for ‘read -e’.
- 'errexit'
- Same as '-e'.
+ ‘errexit’
+ Same as ‘-e’.
- 'errtrace'
- Same as '-E'.
+ ‘errtrace’
+ Same as ‘-E’.
- 'functrace'
- Same as '-T'.
+ ‘functrace’
+ Same as ‘-T’.
- 'hashall'
- Same as '-h'.
+ ‘hashall’
+ Same as ‘-h’.
- 'histexpand'
- Same as '-H'.
+ ‘histexpand’
+ Same as ‘-H’.
- 'history'
+ ‘history’
Enable command history, as described in *note Bash
History Facilities::. This option is on by default in
interactive shells.
- 'ignoreeof'
+ ‘ignoreeof’
An interactive shell will not exit upon reading EOF.
- 'keyword'
- Same as '-k'.
+ ‘keyword’
+ Same as ‘-k’.
- 'monitor'
- Same as '-m'.
+ ‘monitor’
+ Same as ‘-m’.
- 'noclobber'
- Same as '-C'.
+ ‘noclobber’
+ Same as ‘-C’.
- 'noexec'
- Same as '-n'.
+ ‘noexec’
+ Same as ‘-n’.
- 'noglob'
- Same as '-f'.
+ ‘noglob’
+ Same as ‘-f’.
- 'nolog'
+ ‘nolog’
Currently ignored.
- 'notify'
- Same as '-b'.
+ ‘notify’
+ Same as ‘-b’.
- 'nounset'
- Same as '-u'.
+ ‘nounset’
+ Same as ‘-u’.
- 'onecmd'
- Same as '-t'.
+ ‘onecmd’
+ Same as ‘-t’.
- 'physical'
- Same as '-P'.
+ ‘physical’
+ Same as ‘-P’.
- 'pipefail'
+ ‘pipefail’
If set, the return value of a pipeline is the value of
the last (rightmost) command to exit with a non-zero
status, or zero if all commands in the pipeline exit
successfully. This option is disabled by default.
- 'posix'
+ ‘posix’
Change the behavior of Bash where the default operation
differs from the POSIX standard to match the standard
(*note Bash POSIX Mode::). This is intended to make Bash
behave as a strict superset of that standard.
- 'privileged'
- Same as '-p'.
+ ‘privileged’
+ Same as ‘-p’.
- 'verbose'
- Same as '-v'.
+ ‘verbose’
+ Same as ‘-v’.
- 'vi'
- Use a 'vi'-style line editing interface. This also
- affects the editing interface used for 'read -e'.
+ ‘vi’
+ Use a ‘vi’-style line editing interface. This also
+ affects the editing interface used for ‘read -e’.
- 'xtrace'
- Same as '-x'.
+ ‘xtrace’
+ Same as ‘-x’.
- '-p'
- Turn on privileged mode. In this mode, the '$BASH_ENV' and
- '$ENV' files are not processed, shell functions are not
- inherited from the environment, and the 'SHELLOPTS',
- 'BASHOPTS', 'CDPATH' and 'GLOBIGNORE' variables, if they
+ ‘-p’
+ Turn on privileged mode. In this mode, the ‘$BASH_ENV’ and
+ ‘$ENV’ files are not processed, shell functions are not
+ inherited from the environment, and the ‘SHELLOPTS’,
+ ‘BASHOPTS’, ‘CDPATH’ and ‘GLOBIGNORE’ variables, if they
appear in the environment, are ignored. If the shell is
started with the effective user (group) id not equal to the
- real user (group) id, and the '-p' option is not supplied,
+ real user (group) id, and the ‘-p’ option is not supplied,
these actions are taken and the effective user id is set to
- the real user id. If the '-p' option is supplied at startup,
+ the real user id. If the ‘-p’ option is supplied at startup,
the effective user id is not reset. Turning this option off
causes the effective user and group ids to be set to the real
user and group ids.
- '-r'
+ ‘-r’
Enable restricted shell mode (*note The Restricted Shell::).
This option cannot be unset once it has been set.
- '-t'
+ ‘-t’
Exit after reading and executing one command.
- '-u'
+ ‘-u’
Treat unset variables and parameters other than the special
- parameters '@' or '*', or array variables subscripted with '@'
- or '*', as an error when performing parameter expansion. An
+ parameters ‘@’ or ‘*’, or array variables subscripted with ‘@’
+ or ‘*’, as an error when performing parameter expansion. An
error message will be written to the standard error, and a
non-interactive shell will exit.
- '-v'
+ ‘-v’
Print shell input lines as they are read.
- '-x'
- Print a trace of simple commands, 'for' commands, 'case'
- commands, 'select' commands, and arithmetic 'for' commands and
+ ‘-x’
+ Print a trace of simple commands, ‘for’ commands, ‘case’
+ commands, ‘select’ commands, and arithmetic ‘for’ commands and
their arguments or associated word lists to standard error
after they are expanded and before they are executed. The
- shell prints the expanded value of the 'PS4' variable before
+ shell prints the expanded value of the ‘PS4’ variable before
the command and its expanded arguments.
- '-B'
+ ‘-B’
The shell will perform brace expansion (*note Brace
Expansion::). This option is on by default.
- '-C'
- Prevent output redirection using '>', '>&', and '<>' from
+ ‘-C’
+ Prevent output redirection using ‘>’, ‘>&’, and ‘<>’ from
overwriting existing files.
- '-E'
- If set, any trap on 'ERR' is inherited by shell functions,
+ ‘-E’
+ If set, any trap on ‘ERR’ is inherited by shell functions,
command substitutions, and commands executed in a subshell
- environment. The 'ERR' trap is normally not inherited in such
+ environment. The ‘ERR’ trap is normally not inherited in such
cases.
- '-H'
- Enable '!' style history substitution (*note History
+ ‘-H’
+ Enable ‘!’ style history substitution (*note History
Interaction::). This option is on by default for interactive
shells.
- '-P'
+ ‘-P’
If set, do not resolve symbolic links when performing commands
- such as 'cd' which change the current directory. The physical
+ such as ‘cd’ which change the current directory. The physical
directory is used instead. By default, Bash follows the
logical chain of directories when performing commands which
change the current directory.
- For example, if '/usr/sys' is a symbolic link to
- '/usr/local/sys' then:
+ For example, if ‘/usr/sys’ is a symbolic link to
+ ‘/usr/local/sys’ then:
$ cd /usr/sys; echo $PWD
/usr/sys
$ cd ..; pwd
/usr
- If 'set -P' is on, then:
+ If ‘set -P’ is on, then:
$ cd /usr/sys; echo $PWD
/usr/local/sys
$ cd ..; pwd
/usr/local
- '-T'
- If set, any trap on 'DEBUG' and 'RETURN' are inherited by
+ ‘-T’
+ If set, any trap on ‘DEBUG’ and ‘RETURN’ are inherited by
shell functions, command substitutions, and commands executed
- in a subshell environment. The 'DEBUG' and 'RETURN' traps are
+ in a subshell environment. The ‘DEBUG’ and ‘RETURN’ traps are
normally not inherited in such cases.
- '--'
+ ‘--’
If no arguments follow this option, then the positional
parameters are unset. Otherwise, the positional parameters
are set to the ARGUMENTS, even if some of them begin with a
- '-'.
+ ‘-’.
- '-'
+ ‘-’
Signal the end of options, cause all remaining ARGUMENTS to be
- assigned to the positional parameters. The '-x' and '-v'
+ assigned to the positional parameters. The ‘-x’ and ‘-v’
options are turned off. If there are no arguments, the
positional parameters remain unchanged.
- Using '+' rather than '-' causes these options to be turned off.
+ Using ‘+’ rather than ‘-’ causes these options to be turned off.
The options can also be used upon invocation of the shell. The
- current set of options may be found in '$-'.
+ current set of options may be found in ‘$-’.
The remaining N ARGUMENTS are positional parameters and are
- assigned, in order, to '$1', '$2', ... '$N'. The special parameter
- '#' is set to N.
+ assigned, in order, to ‘$1’, ‘$2’, ... ‘$N’. The special parameter
+ ‘#’ is set to N.
The return status is always zero unless an invalid option is
supplied.
This builtin allows you to change additional shell optional behavior.
-'shopt'
+‘shopt’
shopt [-pqsu] [-o] [OPTNAME ...]
Toggle the values of settings controlling optional shell behavior.
- The settings can be either those listed below, or, if the '-o'
- option is used, those available with the '-o' option to the 'set'
+ The settings can be either those listed below, or, if the ‘-o’
+ option is used, those available with the ‘-o’ option to the ‘set’
builtin command (*note The Set Builtin::). With no options, or
- with the '-p' option, a list of all settable options is displayed,
+ with the ‘-p’ option, a list of all settable options is displayed,
with an indication of whether or not each is set; if OPTNAMEs are
- supplied, the output is restricted to those options. The '-p'
+ supplied, the output is restricted to those options. The ‘-p’
option causes output to be displayed in a form that may be reused
as input. Other options have the following meanings:
- '-s'
+ ‘-s’
Enable (set) each OPTNAME.
- '-u'
+ ‘-u’
Disable (unset) each OPTNAME.
- '-q'
+ ‘-q’
Suppresses normal output; the return status indicates whether
the OPTNAME is set or unset. If multiple OPTNAME arguments
- are given with '-q', the return status is zero if all OPTNAMEs
+ are given with ‘-q’, the return status is zero if all OPTNAMEs
are enabled; non-zero otherwise.
- '-o'
+ ‘-o’
Restricts the values of OPTNAME to be those defined for the
- '-o' option to the 'set' builtin (*note The Set Builtin::).
+ ‘-o’ option to the ‘set’ builtin (*note The Set Builtin::).
- If either '-s' or '-u' is used with no OPTNAME arguments, 'shopt'
+ If either ‘-s’ or ‘-u’ is used with no OPTNAME arguments, ‘shopt’
shows only those options which are set or unset, respectively.
- Unless otherwise noted, the 'shopt' options are disabled (off) by
+ Unless otherwise noted, the ‘shopt’ options are disabled (off) by
default.
The return status when listing options is zero if all OPTNAMEs are
the return status is zero unless an OPTNAME is not a valid shell
option.
- The list of 'shopt' options is:
+ The list of ‘shopt’ options is:
- 'array_expand_once'
+ ‘array_expand_once’
If set, the shell suppresses multiple evaluation of
associative and indexed array subscripts during arithmetic
expression evaluation, while executing builtins that can
perform variable assignments, and while executing builtins
that perform array dereferencing.
- 'assoc_expand_once'
- Deprecated; a synonym for 'array_expand_once'.
+ ‘assoc_expand_once’
+ Deprecated; a synonym for ‘array_expand_once’.
- 'autocd'
+ ‘autocd’
If set, a command name that is the name of a directory is
- executed as if it were the argument to the 'cd' command. This
+ executed as if it were the argument to the ‘cd’ command. This
option is only used by interactive shells.
- 'cdable_vars'
- If this is set, an argument to the 'cd' builtin command that
+ ‘cdable_vars’
+ If this is set, an argument to the ‘cd’ builtin command that
is not a directory is assumed to be the name of a variable
whose value is the directory to change to.
- 'cdspell'
+ ‘cdspell’
If set, minor errors in the spelling of a directory component
- in a 'cd' command will be corrected. The errors checked for
+ in a ‘cd’ command will be corrected. The errors checked for
are transposed characters, a missing character, and a
character too many. If a correction is found, the corrected
path is printed, and the command proceeds. This option is
only used by interactive shells.
- 'checkhash'
+ ‘checkhash’
If this is set, Bash checks that a command found in the hash
table exists before trying to execute it. If a hashed command
no longer exists, a normal path search is performed.
- 'checkjobs'
+ ‘checkjobs’
If set, Bash lists the status of any stopped and running jobs
before exiting an interactive shell. If any jobs are running,
this causes the exit to be deferred until a second exit is
Control::). The shell always postpones exiting if any jobs
are stopped.
- 'checkwinsize'
+ ‘checkwinsize’
If set, Bash checks the window size after each external
(non-builtin) command and, if necessary, updates the values of
- 'LINES' and 'COLUMNS'. This option is enabled by default.
+ ‘LINES’ and ‘COLUMNS’. This option is enabled by default.
- 'cmdhist'
+ ‘cmdhist’
If set, Bash attempts to save all lines of a multiple-line
command in the same history entry. This allows easy
re-editing of multi-line commands. This option is enabled by
default, but only has an effect if command history is enabled
(*note Bash History Facilities::).
- 'compat31'
- 'compat32'
- 'compat40'
- 'compat41'
- 'compat42'
- 'compat43'
- 'compat44'
+ ‘compat31’
+ ‘compat32’
+ ‘compat40’
+ ‘compat41’
+ ‘compat42’
+ ‘compat43’
+ ‘compat44’
These control aspects of the shell's compatibility mode (*note
Shell Compatibility Mode::).
- 'complete_fullquote'
+ ‘complete_fullquote’
If set, Bash quotes all shell metacharacters in filenames and
directory names when performing completion. If not set, Bash
removes metacharacters such as the dollar sign from the set of
set by default, which is the default Bash behavior in versions
through 4.2.
- 'direxpand'
+ ‘direxpand’
If set, Bash replaces directory names with the results of word
expansion when performing filename completion. This changes
the contents of the Readline editing buffer. If not set, Bash
attempts to preserve what the user typed.
- 'dirspell'
+ ‘dirspell’
If set, Bash attempts spelling correction on directory names
during word completion if the directory name initially
supplied does not exist.
- 'dotglob'
+ ‘dotglob’
If set, Bash includes filenames beginning with a '.' in the
- results of filename expansion. The filenames '.' and '..'
- must always be matched explicitly, even if 'dotglob' is set.
+ results of filename expansion. The filenames ‘.’ and ‘..’
+ must always be matched explicitly, even if ‘dotglob’ is set.
- 'execfail'
+ ‘execfail’
If this is set, a non-interactive shell will not exit if it
- cannot execute the file specified as an argument to the 'exec'
- builtin command. An interactive shell does not exit if 'exec'
+ cannot execute the file specified as an argument to the ‘exec’
+ builtin command. An interactive shell does not exit if ‘exec’
fails.
- 'expand_aliases'
+ ‘expand_aliases’
If set, aliases are expanded as described below under Aliases,
*note Aliases::. This option is enabled by default for
interactive shells.
- 'extdebug'
+ ‘extdebug’
If set at shell invocation, or in a shell startup file,
arrange to execute the debugger profile before the shell
- starts, identical to the '--debugger' option. If set after
+ starts, identical to the ‘--debugger’ option. If set after
invocation, behavior intended for use by debuggers is enabled:
- 1. The '-F' option to the 'declare' builtin (*note Bash
+ 1. The ‘-F’ option to the ‘declare’ builtin (*note Bash
Builtins::) displays the source file name and line number
corresponding to each function name supplied as an
argument.
- 2. If the command run by the 'DEBUG' trap returns a non-zero
+ 2. If the command run by the ‘DEBUG’ trap returns a non-zero
value, the next command is skipped and not executed.
- 3. If the command run by the 'DEBUG' trap returns a value of
+ 3. If the command run by the ‘DEBUG’ trap returns a value of
2, and the shell is executing in a subroutine (a shell
- function or a shell script executed by the '.' or
- 'source' builtins), the shell simulates a call to
- 'return'.
+ function or a shell script executed by the ‘.’ or
+ ‘source’ builtins), the shell simulates a call to
+ ‘return’.
- 4. 'BASH_ARGC' and 'BASH_ARGV' are updated as described in
+ 4. ‘BASH_ARGC’ and ‘BASH_ARGV’ are updated as described in
their descriptions (*note Bash Variables::).
5. Function tracing is enabled: command substitution, shell
- functions, and subshells invoked with '( COMMAND )'
- inherit the 'DEBUG' and 'RETURN' traps.
+ functions, and subshells invoked with ‘( COMMAND )’
+ inherit the ‘DEBUG’ and ‘RETURN’ traps.
6. Error tracing is enabled: command substitution, shell
- functions, and subshells invoked with '( COMMAND )'
- inherit the 'ERR' trap.
+ functions, and subshells invoked with ‘( COMMAND )’
+ inherit the ‘ERR’ trap.
- 'extglob'
+ ‘extglob’
If set, the extended pattern matching features described above
(*note Pattern Matching::) are enabled.
- 'extquote'
- If set, '$'STRING'' and '$"STRING"' quoting is performed
- within '${PARAMETER}' expansions enclosed in double quotes.
+ ‘extquote’
+ If set, ‘$'STRING'’ and ‘$"STRING"’ quoting is performed
+ within ‘${PARAMETER}’ expansions enclosed in double quotes.
This option is enabled by default.
- 'failglob'
+ ‘failglob’
If set, patterns which fail to match filenames during filename
expansion result in an expansion error.
- 'force_fignore'
- If set, the suffixes specified by the 'FIGNORE' shell variable
+ ‘force_fignore’
+ If set, the suffixes specified by the ‘FIGNORE’ shell variable
cause words to be ignored when performing word completion even
if the ignored words are the only possible completions. *Note
- Bash Variables::, for a description of 'FIGNORE'. This option
+ Bash Variables::, for a description of ‘FIGNORE’. This option
is enabled by default.
- 'globasciiranges'
+ ‘globasciiranges’
If set, range expressions used in pattern matching bracket
expressions (*note Pattern Matching::) behave as if in the
traditional C locale when performing comparisons. That is,
the current locale's collating sequence is not taken into
- account, so 'b' will not collate between 'A' and 'B', and
+ account, so ‘b’ will not collate between ‘A’ and ‘B’, and
upper-case and lower-case ASCII characters will collate
together.
- 'globskipdots'
- If set, filename expansion will never match the filenames '.'
- and '..', even if the pattern begins with a '.'. This option
+ ‘globskipdots’
+ If set, filename expansion will never match the filenames ‘.’
+ and ‘..’, even if the pattern begins with a ‘.’. This option
is enabled by default.
- 'globstar'
- If set, the pattern '**' used in a filename expansion context
+ ‘globstar’
+ If set, the pattern ‘**’ used in a filename expansion context
will match all files and zero or more directories and
- subdirectories. If the pattern is followed by a '/', only
+ subdirectories. If the pattern is followed by a ‘/’, only
directories and subdirectories match.
- 'gnu_errfmt'
+ ‘gnu_errfmt’
If set, shell error messages are written in the standard GNU
error message format.
- 'histappend'
+ ‘histappend’
If set, the history list is appended to the file named by the
- value of the 'HISTFILE' variable when the shell exits, rather
+ value of the ‘HISTFILE’ variable when the shell exits, rather
than overwriting the file.
- 'histreedit'
+ ‘histreedit’
If set, and Readline is being used, a user is given the
opportunity to re-edit a failed history substitution.
- 'histverify'
+ ‘histverify’
If set, and Readline is being used, the results of history
substitution are not immediately passed to the shell parser.
Instead, the resulting line is loaded into the Readline
editing buffer, allowing further modification.
- 'hostcomplete'
+ ‘hostcomplete’
If set, and Readline is being used, Bash will attempt to
- perform hostname completion when a word containing a '@' is
+ perform hostname completion when a word containing a ‘@’ is
being completed (*note Commands For Completion::). This
option is enabled by default.
- 'huponexit'
- If set, Bash will send 'SIGHUP' to all jobs when an
+ ‘huponexit’
+ If set, Bash will send ‘SIGHUP’ to all jobs when an
interactive login shell exits (*note Signals::).
- 'inherit_errexit'
+ ‘inherit_errexit’
If set, command substitution inherits the value of the
- 'errexit' option, instead of unsetting it in the subshell
+ ‘errexit’ option, instead of unsetting it in the subshell
environment. This option is enabled when POSIX mode is
enabled.
- 'interactive_comments'
- Allow a word beginning with '#' to cause that word and all
+ ‘interactive_comments’
+ Allow a word beginning with ‘#’ to cause that word and all
remaining characters on that line to be ignored in an
interactive shell. This option is enabled by default.
- 'lastpipe'
+ ‘lastpipe’
If set, and job control is not active, the shell runs the last
command of a pipeline not executed in the background in the
current shell environment.
- 'lithist'
- If enabled, and the 'cmdhist' option is enabled, multi-line
+ ‘lithist’
+ If enabled, and the ‘cmdhist’ option is enabled, multi-line
commands are saved to the history with embedded newlines
rather than using semicolon separators where possible.
- 'localvar_inherit'
+ ‘localvar_inherit’
If set, local variables inherit the value and attributes of a
variable of the same name that exists at a previous scope
- before any new value is assigned. The 'nameref' attribute is
+ before any new value is assigned. The ‘nameref’ attribute is
not inherited.
- 'localvar_unset'
- If set, calling 'unset' on local variables in previous
+ ‘localvar_unset’
+ If set, calling ‘unset’ on local variables in previous
function scopes marks them so subsequent lookups find them
unset until that function returns. This is identical to the
behavior of unsetting local variables at the current function
scope.
- 'login_shell'
+ ‘login_shell’
The shell sets this option if it is started as a login shell
(*note Invoking Bash::). The value may not be changed.
- 'mailwarn'
+ ‘mailwarn’
If set, and a file that Bash is checking for mail has been
- accessed since the last time it was checked, the message '"The
- mail in MAILFILE has been read"' is displayed.
+ accessed since the last time it was checked, the message ‘"The
+ mail in MAILFILE has been read"’ is displayed.
- 'no_empty_cmd_completion'
+ ‘no_empty_cmd_completion’
If set, and Readline is being used, Bash will not attempt to
- search the 'PATH' for possible completions when completion is
+ search the ‘PATH’ for possible completions when completion is
attempted on an empty line.
- 'nocaseglob'
+ ‘nocaseglob’
If set, Bash matches filenames in a case-insensitive fashion
when performing filename expansion.
- 'nocasematch'
+ ‘nocasematch’
If set, Bash matches patterns in a case-insensitive fashion
- when performing matching while executing 'case' or '[['
+ when performing matching while executing ‘case’ or ‘[[’
conditional commands (*note Conditional Constructs::, when
performing pattern substitution word expansions, or when
filtering possible completions as part of programmable
completion.
- 'noexpand_translation'
+ ‘noexpand_translation’
If set, Bash encloses the translated results of $"..."
quoting in single quotes instead of double quotes. If the
string is not translated, this has no effect.
- 'nullglob'
+ ‘nullglob’
If set, filename expansion patterns which match no files
(*note Filename Expansion::) expand to nothing and are
removed, rather than expanding to themselves.
- 'patsub_replacement'
- If set, Bash expands occurrences of '&' in the replacement
+ ‘patsub_replacement’
+ If set, Bash expands occurrences of ‘&’ in the replacement
string of pattern substitution to the text matched by the
pattern, as described above (*note Shell Parameter
Expansion::). This option is enabled by default.
- 'progcomp'
+ ‘progcomp’
If set, the programmable completion facilities (*note
Programmable Completion::) are enabled. This option is
enabled by default.
- 'progcomp_alias'
+ ‘progcomp_alias’
If set, and programmable completion is enabled, Bash treats a
command name that doesn't have any completions as a possible
alias and attempts alias expansion. If it has an alias, Bash
attempts programmable completion using the command word
resulting from the expanded alias.
- 'promptvars'
+ ‘promptvars’
If set, prompt strings undergo parameter expansion, command
substitution, arithmetic expansion, and quote removal after
being expanded as described below (*note Controlling the
Prompt::). This option is enabled by default.
- 'restricted_shell'
+ ‘restricted_shell’
The shell sets this option if it is started in restricted mode
(*note The Restricted Shell::). The value may not be changed.
This is not reset when the startup files are executed,
allowing the startup files to discover whether or not a shell
is restricted.
- 'shift_verbose'
- If this is set, the 'shift' builtin prints an error message
+ ‘shift_verbose’
+ If this is set, the ‘shift’ builtin prints an error message
when the shift count exceeds the number of positional
parameters.
- 'sourcepath'
- If set, the '.' ('source') builtin uses the value of 'PATH' to
+ ‘sourcepath’
+ If set, the ‘.’ (‘source’) builtin uses the value of ‘PATH’ to
find the directory containing the file supplied as an
argument. This option is enabled by default.
- 'varredir_close'
+ ‘varredir_close’
If set, the shell automatically closes file descriptors
- assigned using the '{varname}' redirection syntax (*note
+ assigned using the ‘{varname}’ redirection syntax (*note
Redirections::) instead of leaving them open when the command
completes.
- 'xpg_echo'
- If set, the 'echo' builtin expands backslash-escape sequences
- by default. If the 'posix' shell option (*note The Set
- Builtin::) is also enabled, 'echo' does not interpret any
+ ‘xpg_echo’
+ If set, the ‘echo’ builtin expands backslash-escape sequences
+ by default. If the ‘posix’ shell option (*note The Set
+ Builtin::) is also enabled, ‘echo’ does not interpret any
options.
\1f
Bash uses certain shell variables in the same way as the Bourne shell.
In some cases, Bash assigns a default value to the variable.
-'CDPATH'
+‘CDPATH’
A colon-separated list of directories used as a search path for the
- 'cd' builtin command.
+ ‘cd’ builtin command.
-'HOME'
- The current user's home directory; the default for the 'cd' builtin
+‘HOME’
+ The current user's home directory; the default for the ‘cd’ builtin
command. The value of this variable is also used by tilde
expansion (*note Tilde Expansion::).
-'IFS'
+‘IFS’
A list of characters that separate fields; used when the shell
splits words as part of expansion.
-'MAIL'
+‘MAIL’
If this parameter is set to a filename or directory name and the
- 'MAILPATH' variable is not set, Bash informs the user of the
+ ‘MAILPATH’ variable is not set, Bash informs the user of the
arrival of mail in the specified file or Maildir-format directory.
-'MAILPATH'
+‘MAILPATH’
A colon-separated list of filenames which the shell periodically
checks for new mail. Each list entry can specify the message that
is printed when new mail arrives in the mail file by separating the
- filename from the message with a '?'. When used in the text of the
- message, '$_' expands to the name of the current mail file.
+ filename from the message with a ‘?’. When used in the text of the
+ message, ‘$_’ expands to the name of the current mail file.
-'OPTARG'
- The value of the last option argument processed by the 'getopts'
+‘OPTARG’
+ The value of the last option argument processed by the ‘getopts’
builtin.
-'OPTIND'
- The index of the last option argument processed by the 'getopts'
+‘OPTIND’
+ The index of the last option argument processed by the ‘getopts’
builtin.
-'PATH'
+‘PATH’
A colon-separated list of directories in which the shell looks for
commands. A zero-length (null) directory name in the value of
- 'PATH' indicates the current directory. A null directory name may
+ ‘PATH’ indicates the current directory. A null directory name may
appear as two adjacent colons, or as an initial or trailing colon.
-'PS1'
- The primary prompt string. The default value is '\s-\v\$ '. *Note
+‘PS1’
+ The primary prompt string. The default value is ‘\s-\v\$ ’. *Note
Controlling the Prompt::, for the complete list of escape sequences
- that are expanded before 'PS1' is displayed.
+ that are expanded before ‘PS1’ is displayed.
-'PS2'
- The secondary prompt string. The default value is '> '. 'PS2' is
- expanded in the same way as 'PS1' before being displayed.
+‘PS2’
+ The secondary prompt string. The default value is ‘> ’. ‘PS2’ is
+ expanded in the same way as ‘PS1’ before being displayed.
\1f
File: bashref.info, Node: Bash Variables, Prev: Bourne Shell Variables, Up: Shell Variables
variables for controlling the job control facilities (*note Job Control
Variables::).
-'_'
+‘_’
($_, an underscore.) At shell startup, set to the pathname used to
invoke the shell or shell script being executed as passed in the
environment or argument list. Subsequently, expands to the last
command. When checking mail, this parameter holds the name of the
mail file.
-'BASH'
+‘BASH’
The full pathname used to execute the current instance of Bash.
-'BASHOPTS'
+‘BASHOPTS’
A colon-separated list of enabled shell options. Each word in the
- list is a valid argument for the '-s' option to the 'shopt' builtin
+ list is a valid argument for the ‘-s’ option to the ‘shopt’ builtin
command (*note The Shopt Builtin::). The options appearing in
- 'BASHOPTS' are those reported as 'on' by 'shopt'. If this variable
+ ‘BASHOPTS’ are those reported as ‘on’ by ‘shopt’. If this variable
is in the environment when Bash starts up, each shell option in the
list will be enabled before reading any startup files. This
variable is readonly.
-'BASHPID'
+‘BASHPID’
Expands to the process ID of the current Bash process. This
- differs from '$$' under certain circumstances, such as subshells
+ differs from ‘$$’ under certain circumstances, such as subshells
that do not require Bash to be re-initialized. Assignments to
- 'BASHPID' have no effect. If 'BASHPID' is unset, it loses its
+ ‘BASHPID’ have no effect. If ‘BASHPID’ is unset, it loses its
special properties, even if it is subsequently reset.
-'BASH_ALIASES'
+‘BASH_ALIASES’
An associative array variable whose members correspond to the
- internal list of aliases as maintained by the 'alias' builtin.
+ internal list of aliases as maintained by the ‘alias’ builtin.
(*note Bourne Shell Builtins::). Elements added to this array
appear in the alias list; however, unsetting array elements
currently does not cause aliases to be removed from the alias list.
- If 'BASH_ALIASES' is unset, it loses its special properties, even
+ If ‘BASH_ALIASES’ is unset, it loses its special properties, even
if it is subsequently reset.
-'BASH_ARGC'
+‘BASH_ARGC’
An array variable whose values are the number of parameters in each
frame of the current Bash execution call stack. The number of
parameters to the current subroutine (shell function or script
- executed with '.' or 'source') is at the top of the stack. When a
+ executed with ‘.’ or ‘source’) is at the top of the stack. When a
subroutine is executed, the number of parameters passed is pushed
- onto 'BASH_ARGC'. The shell sets 'BASH_ARGC' only when in extended
+ onto ‘BASH_ARGC’. The shell sets ‘BASH_ARGC’ only when in extended
debugging mode (see *note The Shopt Builtin:: for a description of
- the 'extdebug' option to the 'shopt' builtin). Setting 'extdebug'
+ the ‘extdebug’ option to the ‘shopt’ builtin). Setting ‘extdebug’
after the shell has started to execute a script, or referencing
- this variable when 'extdebug' is not set, may result in
- inconsistent values. Assignments to 'BASH_ARGC' have no effect,
+ this variable when ‘extdebug’ is not set, may result in
+ inconsistent values. Assignments to ‘BASH_ARGC’ have no effect,
and it may not be unset.
-'BASH_ARGV'
+‘BASH_ARGV’
An array variable containing all of the parameters in the current
Bash execution call stack. The final parameter of the last
subroutine call is at the top of the stack; the first parameter of
the initial call is at the bottom. When a subroutine is executed,
- the parameters supplied are pushed onto 'BASH_ARGV'. The shell
- sets 'BASH_ARGV' only when in extended debugging mode (see *note
- The Shopt Builtin:: for a description of the 'extdebug' option to
- the 'shopt' builtin). Setting 'extdebug' after the shell has
+ the parameters supplied are pushed onto ‘BASH_ARGV’. The shell
+ sets ‘BASH_ARGV’ only when in extended debugging mode (see *note
+ The Shopt Builtin:: for a description of the ‘extdebug’ option to
+ the ‘shopt’ builtin). Setting ‘extdebug’ after the shell has
started to execute a script, or referencing this variable when
- 'extdebug' is not set, may result in inconsistent values.
- Assignments to 'BASH_ARGV' have no effect, and it may not be unset.
+ ‘extdebug’ is not set, may result in inconsistent values.
+ Assignments to ‘BASH_ARGV’ have no effect, and it may not be unset.
-'BASH_ARGV0'
+‘BASH_ARGV0’
When referenced, this variable expands to the name of the shell or
- shell script (identical to '$0'; *Note Special Parameters::, for
+ shell script (identical to ‘$0’; *Note Special Parameters::, for
the description of special parameter 0). Assignment to
- 'BASH_ARGV0' causes the value assigned to also be assigned to '$0'.
- If 'BASH_ARGV0' is unset, it loses its special properties, even if
+ ‘BASH_ARGV0’ causes the value assigned to also be assigned to ‘$0’.
+ If ‘BASH_ARGV0’ is unset, it loses its special properties, even if
it is subsequently reset.
-'BASH_CMDS'
+‘BASH_CMDS’
An associative array variable whose members correspond to the
- internal hash table of commands as maintained by the 'hash' builtin
+ internal hash table of commands as maintained by the ‘hash’ builtin
(*note Bourne Shell Builtins::). Elements added to this array
appear in the hash table; however, unsetting array elements
currently does not cause command names to be removed from the hash
- table. If 'BASH_CMDS' is unset, it loses its special properties,
+ table. If ‘BASH_CMDS’ is unset, it loses its special properties,
even if it is subsequently reset.
-'BASH_COMMAND'
+‘BASH_COMMAND’
The command currently being executed or about to be executed,
unless the shell is executing a command as the result of a trap, in
which case it is the command executing at the time of the trap. If
- 'BASH_COMMAND' is unset, it loses its special properties, even if
+ ‘BASH_COMMAND’ is unset, it loses its special properties, even if
it is subsequently reset.
-'BASH_COMPAT'
+‘BASH_COMPAT’
The value is used to set the shell's compatibility level. *Note
Shell Compatibility Mode::, for a description of the various
compatibility levels and their effects. The value may be a decimal
number (e.g., 4.2) or an integer (e.g., 42) corresponding to the
- desired compatibility level. If 'BASH_COMPAT' is unset or set to
+ desired compatibility level. If ‘BASH_COMPAT’ is unset or set to
the empty string, the compatibility level is set to the default for
- the current version. If 'BASH_COMPAT' is set to a value that is
+ the current version. If ‘BASH_COMPAT’ is set to a value that is
not one of the valid compatibility levels, the shell prints an
error message and sets the compatibility level to the default for
- the current version. The valid values correspond to the
- compatibility levels described below (*note Shell Compatibility
+ the current version. A subset of the valid values correspond to
+ the compatibility levels described below (*note Shell Compatibility
Mode::). For example, 4.2 and 42 are valid values that correspond
- to the 'compat42' 'shopt' option and set the compatibility level to
+ to the ‘compat42’ ‘shopt’ option and set the compatibility level to
42. The current version is also a valid value.
-'BASH_ENV'
+‘BASH_ENV’
If this variable is set when Bash is invoked to execute a shell
script, its value is expanded and used as the name of a startup
file to read before executing the script. *Note Bash Startup
Files::.
-'BASH_EXECUTION_STRING'
- The command argument to the '-c' invocation option.
+‘BASH_EXECUTION_STRING’
+ The command argument to the ‘-c’ invocation option.
-'BASH_LINENO'
+‘BASH_LINENO’
An array variable whose members are the line numbers in source
- files where each corresponding member of 'FUNCNAME' was invoked.
- '${BASH_LINENO[$i]}' is the line number in the source file
- ('${BASH_SOURCE[$i+1]}') where '${FUNCNAME[$i]}' was called (or
- '${BASH_LINENO[$i-1]}' if referenced within another shell
- function). Use 'LINENO' to obtain the current line number.
- Assignments to 'BASH_LINENO' have no effect, and it may not be
+ files where each corresponding member of ‘FUNCNAME’ was invoked.
+ ‘${BASH_LINENO[$i]}’ is the line number in the source file
+ (‘${BASH_SOURCE[$i+1]}’) where ‘${FUNCNAME[$i]}’ was called (or
+ ‘${BASH_LINENO[$i-1]}’ if referenced within another shell
+ function). Use ‘LINENO’ to obtain the current line number.
+ Assignments to ‘BASH_LINENO’ have no effect, and it may not be
unset.
-'BASH_LOADABLES_PATH'
+‘BASH_LOADABLES_PATH’
A colon-separated list of directories in which the shell looks for
- dynamically loadable builtins specified by the 'enable' command.
+ dynamically loadable builtins specified by the ‘enable’ command.
-'BASH_MONOSECONDS'
+‘BASH_MONOSECONDS’
Each time this variable is referenced, it expands to the value
returned by the system's monotonic clock, if one is available. If
- there is no monotonic clock, this is equivalent to 'EPOCHSECONDS'.
- If 'BASH_MONOSECONDS' is unset, it loses its special properties,
+ there is no monotonic clock, this is equivalent to ‘EPOCHSECONDS’.
+ If ‘BASH_MONOSECONDS’ is unset, it loses its special properties,
even if it is subsequently reset.
-'BASH_REMATCH'
- An array variable whose members are assigned by the '=~' binary
- operator to the '[[' conditional command (*note Conditional
+‘BASH_REMATCH’
+ An array variable whose members are assigned by the ‘=~’ binary
+ operator to the ‘[[’ conditional command (*note Conditional
Constructs::). The element with index 0 is the portion of the
string matching the entire regular expression. The element with
index N is the portion of the string matching the Nth parenthesized
subexpression.
-'BASH_SOURCE'
+‘BASH_SOURCE’
An array variable whose members are the source filenames where the
- corresponding shell function names in the 'FUNCNAME' array variable
- are defined. The shell function '${FUNCNAME[$i]}' is defined in
- the file '${BASH_SOURCE[$i]}' and called from
- '${BASH_SOURCE[$i+1]}' Assignments to 'BASH_SOURCE' have no effect,
+ corresponding shell function names in the ‘FUNCNAME’ array variable
+ are defined. The shell function ‘${FUNCNAME[$i]}’ is defined in
+ the file ‘${BASH_SOURCE[$i]}’ and called from
+ ‘${BASH_SOURCE[$i+1]}’ Assignments to ‘BASH_SOURCE’ have no effect,
and it may not be unset.
-'BASH_SUBSHELL'
+‘BASH_SUBSHELL’
Incremented by one within each subshell or subshell environment
when the shell begins executing in that environment. The initial
- value is 0. If 'BASH_SUBSHELL' is unset, it loses its special
+ value is 0. If ‘BASH_SUBSHELL’ is unset, it loses its special
properties, even if it is subsequently reset.
-'BASH_TRAPSIG'
+‘BASH_TRAPSIG’
Set to the signal number corresponding to the trap action being
- executed during its execution. See the description of 'trap'
+ executed during its execution. See the description of ‘trap’
(*note Bourne Shell Builtins::) for information about signal
numbers and trap execution.
-'BASH_VERSINFO'
+‘BASH_VERSINFO’
A readonly array variable (*note Arrays::) whose members hold
version information for this instance of Bash. The values assigned
to the array members are as follows:
- 'BASH_VERSINFO[0]'
- The major version number (the "release").
+ ‘BASH_VERSINFO[0]’
+ The major version number (the “release”).
- 'BASH_VERSINFO[1]'
- The minor version number (the "version").
+ ‘BASH_VERSINFO[1]’
+ The minor version number (the “version”).
- 'BASH_VERSINFO[2]'
+ ‘BASH_VERSINFO[2]’
The patch level.
- 'BASH_VERSINFO[3]'
+ ‘BASH_VERSINFO[3]’
The build version.
- 'BASH_VERSINFO[4]'
- The release status (e.g., 'beta1').
+ ‘BASH_VERSINFO[4]’
+ The release status (e.g., ‘beta’).
- 'BASH_VERSINFO[5]'
- The value of 'MACHTYPE'.
+ ‘BASH_VERSINFO[5]’
+ The value of ‘MACHTYPE’.
-'BASH_VERSION'
+‘BASH_VERSION’
The version number of the current instance of Bash.
-'BASH_XTRACEFD'
+‘BASH_XTRACEFD’
If set to an integer corresponding to a valid file descriptor, Bash
- will write the trace output generated when 'set -x' is enabled to
+ will write the trace output generated when ‘set -x’ is enabled to
that file descriptor. This allows tracing output to be separated
from diagnostic and error messages. The file descriptor is closed
- when 'BASH_XTRACEFD' is unset or assigned a new value. Unsetting
- 'BASH_XTRACEFD' or assigning it the empty string causes the trace
+ when ‘BASH_XTRACEFD’ is unset or assigned a new value. Unsetting
+ ‘BASH_XTRACEFD’ or assigning it the empty string causes the trace
output to be sent to the standard error. Note that setting
- 'BASH_XTRACEFD' to 2 (the standard error file descriptor) and then
+ ‘BASH_XTRACEFD’ to 2 (the standard error file descriptor) and then
unsetting it will result in the standard error being closed.
-'CHILD_MAX'
+‘CHILD_MAX’
Set the number of exited child status values for the shell to
remember. Bash will not allow this value to be decreased below a
POSIX-mandated minimum, and there is a maximum value (currently
8192) that this may not exceed. The minimum value is
system-dependent.
-'COLUMNS'
- Used by the 'select' command to determine the terminal width when
- printing selection lists. Automatically set if the 'checkwinsize'
+‘COLUMNS’
+ Used by the ‘select’ command to determine the terminal width when
+ printing selection lists. Automatically set if the ‘checkwinsize’
option is enabled (*note The Shopt Builtin::), or in an interactive
- shell upon receipt of a 'SIGWINCH'.
+ shell upon receipt of a ‘SIGWINCH’.
-'COMP_CWORD'
- An index into '${COMP_WORDS}' of the word containing the current
+‘COMP_CWORD’
+ An index into ‘${COMP_WORDS}’ of the word containing the current
cursor position. This variable is available only in shell
functions invoked by the programmable completion facilities (*note
Programmable Completion::).
-'COMP_LINE'
+‘COMP_LINE’
The current command line. This variable is available only in shell
functions and external commands invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMP_POINT'
+‘COMP_POINT’
The index of the current cursor position relative to the beginning
of the current command. If the current cursor position is at the
end of the current command, the value of this variable is equal to
- '${#COMP_LINE}'. This variable is available only in shell
+ ‘${#COMP_LINE}’. This variable is available only in shell
functions and external commands invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMP_TYPE'
+‘COMP_TYPE’
Set to an integer value corresponding to the type of completion
attempted that caused a completion function to be called: <TAB>,
- for normal completion, '?', for listing completions after
- successive tabs, '!', for listing alternatives on partial word
- completion, '@', to list completions if the word is not unmodified,
- or '%', for menu completion. This variable is available only in
+ for normal completion, ‘?’, for listing completions after
+ successive tabs, ‘!’, for listing alternatives on partial word
+ completion, ‘@’, to list completions if the word is not unmodified,
+ or ‘%’, for menu completion. This variable is available only in
shell functions and external commands invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMP_KEY'
+‘COMP_KEY’
The key (or final key of a key sequence) used to invoke the current
completion function.
-'COMP_WORDBREAKS'
+‘COMP_WORDBREAKS’
The set of characters that the Readline library treats as word
- separators when performing word completion. If 'COMP_WORDBREAKS'
+ separators when performing word completion. If ‘COMP_WORDBREAKS’
is unset, it loses its special properties, even if it is
subsequently reset.
-'COMP_WORDS'
+‘COMP_WORDS’
An array variable consisting of the individual words in the current
command line. The line is split into words as Readline would split
- it, using 'COMP_WORDBREAKS' as described above. This variable is
+ it, using ‘COMP_WORDBREAKS’ as described above. This variable is
available only in shell functions invoked by the programmable
completion facilities (*note Programmable Completion::).
-'COMPREPLY'
+‘COMPREPLY’
An array variable from which Bash reads the possible completions
generated by a shell function invoked by the programmable
completion facility (*note Programmable Completion::). Each array
element contains one possible completion.
-'COPROC'
+‘COPROC’
An array variable created to hold the file descriptors for output
from and input to an unnamed coprocess (*note Coprocesses::).
-'DIRSTACK'
+‘DIRSTACK’
An array variable containing the current contents of the directory
stack. Directories appear in the stack in the order they are
- displayed by the 'dirs' builtin. Assigning to members of this
+ displayed by the ‘dirs’ builtin. Assigning to members of this
array variable may be used to modify directories already in the
- stack, but the 'pushd' and 'popd' builtins must be used to add and
+ stack, but the ‘pushd’ and ‘popd’ builtins must be used to add and
remove directories. Assignment to this variable will not change
- the current directory. If 'DIRSTACK' is unset, it loses its
+ the current directory. If ‘DIRSTACK’ is unset, it loses its
special properties, even if it is subsequently reset.
-'EMACS'
+‘EMACS’
If Bash finds this variable in the environment when the shell
- starts with value 't', it assumes that the shell is running in an
+ starts with value ‘t’, it assumes that the shell is running in an
Emacs shell buffer and disables line editing.
-'ENV'
- Expanded and executed similarly to 'BASH_ENV' (*note Bash Startup
+‘ENV’
+ Expanded and executed similarly to ‘BASH_ENV’ (*note Bash Startup
Files::) when an interactive shell is invoked in POSIX Mode (*note
Bash POSIX Mode::).
-'EPOCHREALTIME'
+‘EPOCHREALTIME’
Each time this parameter is referenced, it expands to the number of
seconds since the Unix Epoch as a floating point value with
micro-second granularity (see the documentation for the C library
- function 'time' for the definition of Epoch). Assignments to
- 'EPOCHREALTIME' are ignored. If 'EPOCHREALTIME' is unset, it loses
+ function ‘time’ for the definition of Epoch). Assignments to
+ ‘EPOCHREALTIME’ are ignored. If ‘EPOCHREALTIME’ is unset, it loses
its special properties, even if it is subsequently reset.
-'EPOCHSECONDS'
+‘EPOCHSECONDS’
Each time this parameter is referenced, it expands to the number of
seconds since the Unix Epoch (see the documentation for the C
- library function 'time' for the definition of Epoch). Assignments
- to 'EPOCHSECONDS' are ignored. If 'EPOCHSECONDS' is unset, it
+ library function ‘time’ for the definition of Epoch). Assignments
+ to ‘EPOCHSECONDS’ are ignored. If ‘EPOCHSECONDS’ is unset, it
loses its special properties, even if it is subsequently reset.
-'EUID'
+‘EUID’
The numeric effective user id of the current user. This variable
is readonly.
-'EXECIGNORE'
+‘EXECIGNORE’
A colon-separated list of shell patterns (*note Pattern Matching::)
defining the list of filenames to be ignored by command search
- using 'PATH'. Files whose full pathnames match one of these
+ using ‘PATH’. Files whose full pathnames match one of these
patterns are not considered executable files for the purposes of
- completion and command execution via 'PATH' lookup. This does not
- affect the behavior of the '[', 'test', and '[[' commands. Full
+ completion and command execution via ‘PATH’ lookup. This does not
+ affect the behavior of the ‘[’, ‘test’, and ‘[[’ commands. Full
pathnames in the command hash table are not subject to
- 'EXECIGNORE'. Use this variable to ignore shared library files
+ ‘EXECIGNORE’. Use this variable to ignore shared library files
that have the executable bit set, but are not executable files.
- The pattern matching honors the setting of the 'extglob' shell
+ The pattern matching honors the setting of the ‘extglob’ shell
option.
-'FCEDIT'
- The editor used as a default by the '-e' option to the 'fc' builtin
+‘FCEDIT’
+ The editor used as a default by the ‘-e’ option to the ‘fc’ builtin
command.
-'FIGNORE'
+‘FIGNORE’
A colon-separated list of suffixes to ignore when performing
filename completion. A filename whose suffix matches one of the
- entries in 'FIGNORE' is excluded from the list of matched
- filenames. A sample value is '.o:~'
+ entries in ‘FIGNORE’ is excluded from the list of matched
+ filenames. A sample value is ‘.o:~’
-'FUNCNAME'
+‘FUNCNAME’
An array variable containing the names of all shell functions
currently in the execution call stack. The element with index 0 is
the name of any currently-executing shell function. The
- bottom-most element (the one with the highest index) is '"main"'.
+ bottom-most element (the one with the highest index) is ‘"main"’.
This variable exists only when a shell function is executing.
- Assignments to 'FUNCNAME' have no effect. If 'FUNCNAME' is unset,
+ Assignments to ‘FUNCNAME’ have no effect. If ‘FUNCNAME’ is unset,
it loses its special properties, even if it is subsequently reset.
- This variable can be used with 'BASH_LINENO' and 'BASH_SOURCE'.
- Each element of 'FUNCNAME' has corresponding elements in
- 'BASH_LINENO' and 'BASH_SOURCE' to describe the call stack. For
- instance, '${FUNCNAME[$i]}' was called from the file
- '${BASH_SOURCE[$i+1]}' at line number '${BASH_LINENO[$i]}'. The
- 'caller' builtin displays the current call stack using this
+ This variable can be used with ‘BASH_LINENO’ and ‘BASH_SOURCE’.
+ Each element of ‘FUNCNAME’ has corresponding elements in
+ ‘BASH_LINENO’ and ‘BASH_SOURCE’ to describe the call stack. For
+ instance, ‘${FUNCNAME[$i]}’ was called from the file
+ ‘${BASH_SOURCE[$i+1]}’ at line number ‘${BASH_LINENO[$i]}’. The
+ ‘caller’ builtin displays the current call stack using this
information.
-'FUNCNEST'
+‘FUNCNEST’
If set to a numeric value greater than 0, defines a maximum
function nesting level. Function invocations that exceed this
nesting level will cause the current command to abort.
-'GLOBIGNORE'
+‘GLOBIGNORE’
A colon-separated list of patterns defining the set of file names
to be ignored by filename expansion. If a file name matched by a
filename expansion pattern also matches one of the patterns in
- 'GLOBIGNORE', it is removed from the list of matches. The pattern
- matching honors the setting of the 'extglob' shell option.
+ ‘GLOBIGNORE’, it is removed from the list of matches. The pattern
+ matching honors the setting of the ‘extglob’ shell option.
-'GLOBSORT'
+‘GLOBSORT’
Control how the results of filename expansion are sorted. The
value of this variable specifies the sort criteria and sort order
for the results of filename expansion. If this variable is unset
or set to the null string, filename expansion uses the historical
behavior of sorting by name. If set, a valid value begins with an
- optional '+', which is ignored, or '-', which reverses the sort
+ optional ‘+’, which is ignored, or ‘-’, which reverses the sort
order from ascending to descending, followed by a sort specifier.
- The valid sort specifiers are 'name', 'size', 'mtime', 'atime',
- 'ctime', and 'blocks', which sort the files on name, file size,
+ The valid sort specifiers are ‘name’, ‘size’, ‘mtime’, ‘atime’,
+ ‘ctime’, and ‘blocks’, which sort the files on name, file size,
modification time, access time, inode change time, and number of
blocks, respectively.
- For example, a value of '-mtime' sorts the results in descending
+ For example, a value of ‘-mtime’ sorts the results in descending
order by modification time (newest first).
- A sort specifier of 'nosort' disables sorting completely; the
+ A sort specifier of ‘nosort’ disables sorting completely; the
results are returned in the order they are read from the file
system,.
If the sort specifier is missing, it defaults to NAME, so a value
- of '+' is equivalent to the null string, and a value of '-' sorts
+ of ‘+’ is equivalent to the null string, and a value of ‘-’ sorts
by name in descending order.
Any invalid value restores the historical sorting behavior.
-'GROUPS'
+‘GROUPS’
An array variable containing the list of groups of which the
- current user is a member. Assignments to 'GROUPS' have no effect.
- If 'GROUPS' is unset, it loses its special properties, even if it
+ current user is a member. Assignments to ‘GROUPS’ have no effect.
+ If ‘GROUPS’ is unset, it loses its special properties, even if it
is subsequently reset.
-'histchars'
+‘histchars’
Up to three characters which control history expansion, quick
substitution, and tokenization (*note History Interaction::). The
- first character is the "history expansion" character, that is, the
+ first character is the “history expansion” character, that is, the
character which signifies the start of a history expansion,
- normally '!'. The second character is the character which
+ normally ‘!’. The second character is the character which
signifies "quick substitution" when seen as the first character on
- a line, normally '^'. The optional third character is the
+ a line, normally ‘^’. The optional third character is the
character which indicates that the remainder of the line is a
- comment when found as the first character of a word, usually '#'.
+ comment when found as the first character of a word, usually ‘#’.
The history comment character causes history substitution to be
skipped for the remaining words on the line. It does not
necessarily cause the shell parser to treat the rest of the line as
a comment.
-'HISTCMD'
+‘HISTCMD’
The history number, or index in the history list, of the current
- command. Assignments to 'HISTCMD' are ignored. If 'HISTCMD' is
+ command. Assignments to ‘HISTCMD’ are ignored. If ‘HISTCMD’ is
unset, it loses its special properties, even if it is subsequently
reset.
-'HISTCONTROL'
+‘HISTCONTROL’
A colon-separated list of values controlling how commands are saved
- on the history list. If the list of values includes 'ignorespace',
+ on the history list. If the list of values includes ‘ignorespace’,
lines which begin with a space character are not saved in the
- history list. A value of 'ignoredups' causes lines which match the
- previous history entry to not be saved. A value of 'ignoreboth' is
- shorthand for 'ignorespace' and 'ignoredups'. A value of
- 'erasedups' causes all previous lines matching the current line to
+ history list. A value of ‘ignoredups’ causes lines which match the
+ previous history entry to not be saved. A value of ‘ignoreboth’ is
+ shorthand for ‘ignorespace’ and ‘ignoredups’. A value of
+ ‘erasedups’ causes all previous lines matching the current line to
be removed from the history list before that line is saved. Any
- value not in the above list is ignored. If 'HISTCONTROL' is unset,
+ value not in the above list is ignored. If ‘HISTCONTROL’ is unset,
or does not include a valid value, all lines read by the shell
parser are saved on the history list, subject to the value of
- 'HISTIGNORE'. The second and subsequent lines of a multi-line
+ ‘HISTIGNORE’. The second and subsequent lines of a multi-line
compound command are not tested, and are added to the history
- regardless of the value of 'HISTCONTROL'.
+ regardless of the value of ‘HISTCONTROL’.
-'HISTFILE'
+‘HISTFILE’
The name of the file to which the command history is saved. Bash
- assigns a default value of '~/.bash_history'. If 'HISTFILE' is
+ assigns a default value of ‘~/.bash_history’. If ‘HISTFILE’ is
unset or null, the command history is not saved when a shell exits.
-'HISTFILESIZE'
+‘HISTFILESIZE’
The maximum number of lines contained in the history file. When
this variable is assigned a value, the history file is truncated,
if necessary, to contain no more than that number of lines by
this size after writing it when a shell exits. If the value is 0,
the history file is truncated to zero size. Non-numeric values and
numeric values less than zero inhibit truncation. The shell sets
- the default value to the value of 'HISTSIZE' after reading any
+ the default value to the value of ‘HISTSIZE’ after reading any
startup files.
-'HISTIGNORE'
+‘HISTIGNORE’
A colon-separated list of patterns used to decide which command
lines should be saved on the history list. Each pattern is
anchored at the beginning of the line and must match the complete
- line (no implicit '*' is appended). Each pattern is tested against
- the line after the checks specified by 'HISTCONTROL' are applied.
- In addition to the normal shell pattern matching characters, '&'
- matches the previous history line. '&' may be escaped using a
- backslash; the backslash is removed before attempting a match. The
- second and subsequent lines of a multi-line compound command are
- not tested, and are added to the history regardless of the value of
- 'HISTIGNORE'. The pattern matching honors the setting of the
- 'extglob' shell option.
-
- 'HISTIGNORE' subsumes the function of 'HISTCONTROL'. A pattern of
- '&' is identical to 'ignoredups', and a pattern of '[ ]*' is
- identical to 'ignorespace'. Combining these two patterns,
+ line (Bash will not implicitly append a ‘*’). Each pattern is
+ tested against the line after the checks specified by ‘HISTCONTROL’
+ are applied. In addition to the normal shell pattern matching
+ characters, ‘&’ matches the previous history line. ‘&’ may be
+ escaped using a backslash; the backslash is removed before
+ attempting a match. The second and subsequent lines of a
+ multi-line compound command are not tested, and are added to the
+ history regardless of the value of ‘HISTIGNORE’. The pattern
+ matching honors the setting of the ‘extglob’ shell option.
+
+ ‘HISTIGNORE’ subsumes the function of ‘HISTCONTROL’. A pattern of
+ ‘&’ is identical to ‘ignoredups’, and a pattern of ‘[ ]*’ is
+ identical to ‘ignorespace’. Combining these two patterns,
separating them with a colon, provides the functionality of
- 'ignoreboth'.
+ ‘ignoreboth’.
-'HISTSIZE'
+‘HISTSIZE’
The maximum number of commands to remember on the history list. If
the value is 0, commands are not saved in the history list.
Numeric values less than zero result in every command being saved
on the history list (there is no limit). The shell sets the
default value to 500 after reading any startup files.
-'HISTTIMEFORMAT'
+‘HISTTIMEFORMAT’
If this variable is set and not null, its value is used as a format
- string for 'strftime' to print the time stamp associated with each
- history entry displayed by the 'history' builtin. If this variable
- is set, time stamps are written to the history file so they may be
- preserved across shell sessions. This uses the history comment
- character to distinguish timestamps from other history lines.
-
-'HOSTFILE'
- Contains the name of a file in the same format as '/etc/hosts' that
+ string for ‘strftime’(3) to print the time stamp associated with
+ each history entry displayed by the ‘history’ builtin. If this
+ variable is set, time stamps are written to the history file so
+ they may be preserved across shell sessions. This uses the history
+ comment character to distinguish timestamps from other history
+ lines.
+
+‘HOSTFILE’
+ Contains the name of a file in the same format as ‘/etc/hosts’ that
should be read when the shell needs to complete a hostname. The
list of possible hostname completions may be changed while the
shell is running; the next time hostname completion is attempted
after the value is changed, Bash adds the contents of the new file
- to the existing list. If 'HOSTFILE' is set, but has no value, or
- does not name a readable file, Bash attempts to read '/etc/hosts'
+ to the existing list. If ‘HOSTFILE’ is set, but has no value, or
+ does not name a readable file, Bash attempts to read ‘/etc/hosts’
to obtain the list of possible hostname completions. When
- 'HOSTFILE' is unset, the hostname list is cleared.
+ ‘HOSTFILE’ is unset, the hostname list is cleared.
-'HOSTNAME'
+‘HOSTNAME’
The name of the current host.
-'HOSTTYPE'
+‘HOSTTYPE’
A string describing the machine Bash is running on.
-'IGNOREEOF'
- Controls the action of the shell on receipt of an 'EOF' character
+‘IGNOREEOF’
+ Controls the action of the shell on receipt of an ‘EOF’ character
as the sole input. If set, the value denotes the number of
- consecutive 'EOF' characters that can be read as the first
+ consecutive ‘EOF’ characters that can be read as the first
character on an input line before the shell will exit. If the
variable exists but does not have a numeric value, or has no value,
- then the default is 10. If the variable does not exist, then 'EOF'
+ then the default is 10. If the variable does not exist, then ‘EOF’
signifies the end of input to the shell. This is only in effect
for interactive shells.
-'INPUTRC'
+‘INPUTRC’
The name of the Readline initialization file, overriding the
- default of '~/.inputrc'.
+ default of ‘~/.inputrc’.
-'INSIDE_EMACS'
+‘INSIDE_EMACS’
If Bash finds this variable in the environment when the shell
starts, it assumes that the shell is running in an Emacs shell
buffer and may disable line editing depending on the value of
- 'TERM'.
+ ‘TERM’.
-'LANG'
+‘LANG’
Used to determine the locale category for any category not
- specifically selected with a variable starting with 'LC_'.
+ specifically selected with a variable starting with ‘LC_’.
-'LC_ALL'
- This variable overrides the value of 'LANG' and any other 'LC_'
+‘LC_ALL’
+ This variable overrides the value of ‘LANG’ and any other ‘LC_’
variable specifying a locale category.
-'LC_COLLATE'
+‘LC_COLLATE’
This variable determines the collation order used when sorting the
results of filename expansion, and determines the behavior of range
expressions, equivalence classes, and collating sequences within
filename expansion and pattern matching (*note Filename
Expansion::).
-'LC_CTYPE'
+‘LC_CTYPE’
This variable determines the interpretation of characters and the
behavior of character classes within filename expansion and pattern
matching (*note Filename Expansion::).
-'LC_MESSAGES'
+‘LC_MESSAGES’
This variable determines the locale used to translate double-quoted
- strings preceded by a '$' (*note Locale Translation::).
+ strings preceded by a ‘$’ (*note Locale Translation::).
-'LC_NUMERIC'
+‘LC_NUMERIC’
This variable determines the locale category used for number
formatting.
-'LC_TIME'
+‘LC_TIME’
This variable determines the locale category used for data and time
formatting.
-'LINENO'
+‘LINENO’
The line number in the script or shell function currently
- executing. If 'LINENO' is unset, it loses its special properties,
+ executing. If ‘LINENO’ is unset, it loses its special properties,
even if it is subsequently reset.
-'LINES'
- Used by the 'select' command to determine the column length for
- printing selection lists. Automatically set if the 'checkwinsize'
+‘LINES’
+ Used by the ‘select’ command to determine the column length for
+ printing selection lists. Automatically set if the ‘checkwinsize’
option is enabled (*note The Shopt Builtin::), or in an interactive
- shell upon receipt of a 'SIGWINCH'.
+ shell upon receipt of a ‘SIGWINCH’.
-'MACHTYPE'
+‘MACHTYPE’
A string that fully describes the system type on which Bash is
executing, in the standard GNU CPU-COMPANY-SYSTEM format.
-'MAILCHECK'
+‘MAILCHECK’
How often (in seconds) that the shell should check for mail in the
- files specified in the 'MAILPATH' or 'MAIL' variables. The default
+ files specified in the ‘MAILPATH’ or ‘MAIL’ variables. The default
is 60 seconds. When it is time to check for mail, the shell does
so before displaying the primary prompt. If this variable is
unset, or set to a value that is not a number greater than or equal
to zero, the shell disables mail checking.
-'MAPFILE'
- An array variable created to hold the text read by the 'mapfile'
+‘MAPFILE’
+ An array variable created to hold the text read by the ‘mapfile’
builtin when no variable name is supplied.
-'OLDPWD'
- The previous working directory as set by the 'cd' builtin.
+‘OLDPWD’
+ The previous working directory as set by the ‘cd’ builtin.
-'OPTERR'
+‘OPTERR’
If set to the value 1, Bash displays error messages generated by
- the 'getopts' builtin command.
+ the ‘getopts’ builtin command.
-'OSTYPE'
+‘OSTYPE’
A string describing the operating system Bash is running on.
-'PIPESTATUS'
+‘PIPESTATUS’
An array variable (*note Arrays::) containing a list of exit status
values from the processes in the most-recently-executed foreground
pipeline (which may contain only a single command).
-'POSIXLY_CORRECT'
+‘POSIXLY_CORRECT’
If this variable is in the environment when Bash starts, the shell
enters POSIX mode (*note Bash POSIX Mode::) before reading the
- startup files, as if the '--posix' invocation option had been
+ startup files, as if the ‘--posix’ invocation option had been
supplied. If it is set while the shell is running, Bash enables
POSIX mode, as if the command
set -o posix
had been executed. When the shell enters POSIX mode, it sets this
variable if it was not already set.
-'PPID'
+‘PPID’
The process ID of the shell's parent process. This variable is
readonly.
-'PROMPT_COMMAND'
+‘PROMPT_COMMAND’
If this variable is set, and is an array, the value of each set
element is interpreted as a command to execute before printing the
- primary prompt ('$PS1'). If this is set but not an array variable,
+ primary prompt (‘$PS1’). If this is set but not an array variable,
its value is used as a command to execute instead.
-'PROMPT_DIRTRIM'
+‘PROMPT_DIRTRIM’
If set to a number greater than zero, the value is used as the
number of trailing directory components to retain when expanding
- the '\w' and '\W' prompt string escapes (*note Controlling the
+ the ‘\w’ and ‘\W’ prompt string escapes (*note Controlling the
Prompt::). Characters removed are replaced with an ellipsis.
-'PS0'
- The value of this parameter is expanded like 'PS1' and displayed by
+‘PS0’
+ The value of this parameter is expanded like ‘PS1’ and displayed by
interactive shells after reading a command and before the command
is executed.
-'PS3'
- The value of this variable is used as the prompt for the 'select'
- command. If this variable is not set, the 'select' command prompts
- with '#? '
+‘PS3’
+ The value of this variable is used as the prompt for the ‘select’
+ command. If this variable is not set, the ‘select’ command prompts
+ with ‘#? ’
-'PS4'
- The value of this parameter is expanded like 'PS1' and the expanded
+‘PS4’
+ The value of this parameter is expanded like ‘PS1’ and the expanded
value is the prompt printed before the command line is echoed when
- the '-x' option is set (*note The Set Builtin::). The first
+ the ‘-x’ option is set (*note The Set Builtin::). The first
character of the expanded value is replicated multiple times, as
necessary, to indicate multiple levels of indirection. The default
- is '+ '.
+ is ‘+ ’.
-'PWD'
- The current working directory as set by the 'cd' builtin.
+‘PWD’
+ The current working directory as set by the ‘cd’ builtin.
-'RANDOM'
+‘RANDOM’
Each time this parameter is referenced, it expands to a random
integer between 0 and 32767. Assigning a value to this variable
- seeds the random number generator. If 'RANDOM' is unset, it loses
+ seeds the random number generator. If ‘RANDOM’ is unset, it loses
its special properties, even if it is subsequently reset.
-'READLINE_ARGUMENT'
+‘READLINE_ARGUMENT’
Any numeric argument given to a Readline command that was defined
- using 'bind -x' (*note Bash Builtins:: when it was invoked.
+ using ‘bind -x’ (*note Bash Builtins:: when it was invoked.
-'READLINE_LINE'
- The contents of the Readline line buffer, for use with 'bind -x'
+‘READLINE_LINE’
+ The contents of the Readline line buffer, for use with ‘bind -x’
(*note Bash Builtins::).
-'READLINE_MARK'
- The position of the "mark" (saved insertion point) in the Readline
- line buffer, for use with 'bind -x' (*note Bash Builtins::). The
+‘READLINE_MARK’
+ The position of the “mark” (saved insertion point) in the Readline
+ line buffer, for use with ‘bind -x’ (*note Bash Builtins::). The
characters between the insertion point and the mark are often
- called the "region".
+ called the “region”.
-'READLINE_POINT'
+‘READLINE_POINT’
The position of the insertion point in the Readline line buffer,
- for use with 'bind -x' (*note Bash Builtins::).
+ for use with ‘bind -x’ (*note Bash Builtins::).
-'REPLY'
- The default variable for the 'read' builtin.
+‘REPLY’
+ The default variable for the ‘read’ builtin.
-'SECONDS'
+‘SECONDS’
This variable expands to the number of seconds since the shell was
started. Assignment to this variable resets the count to the value
assigned, and the expanded value becomes the value assigned plus
the number of seconds since the assignment. The number of seconds
at shell invocation and the current time are always determined by
- querying the system clock. If 'SECONDS' is unset, it loses its
+ querying the system clock. If ‘SECONDS’ is unset, it loses its
special properties, even if it is subsequently reset.
-'SHELL'
+‘SHELL’
This environment variable expands to the full pathname to the
shell. If it is not set when the shell starts, Bash assigns to it
the full pathname of the current user's login shell.
-'SHELLOPTS'
+‘SHELLOPTS’
A colon-separated list of enabled shell options. Each word in the
- list is a valid argument for the '-o' option to the 'set' builtin
+ list is a valid argument for the ‘-o’ option to the ‘set’ builtin
command (*note The Set Builtin::). The options appearing in
- 'SHELLOPTS' are those reported as 'on' by 'set -o'. If this
+ ‘SHELLOPTS’ are those reported as ‘on’ by ‘set -o’. If this
variable is in the environment when Bash starts up, each shell
option in the list will be enabled before reading any startup
files. This variable is readonly.
-'SHLVL'
+‘SHLVL’
Incremented by one each time a new instance of Bash is started.
This is intended to be a count of how deeply your Bash shells are
nested.
-'SRANDOM'
+‘SRANDOM’
This variable expands to a 32-bit pseudo-random number each time it
is referenced. The random number generator is not linear on
- systems that support '/dev/urandom' or 'arc4random', so each
+ systems that support ‘/dev/urandom’ or ‘arc4random’, so each
returned number has no relationship to the numbers preceding it.
The random number generator cannot be seeded, so assignments to
- this variable have no effect. If 'SRANDOM' is unset, it loses its
+ this variable have no effect. If ‘SRANDOM’ is unset, it loses its
special properties, even if it is subsequently reset.
-'TIMEFORMAT'
+‘TIMEFORMAT’
The value of this parameter is used as a format string specifying
- how the timing information for pipelines prefixed with the 'time'
- reserved word should be displayed. The '%' character introduces an
+ how the timing information for pipelines prefixed with the ‘time’
+ reserved word should be displayed. The ‘%’ character introduces an
escape sequence that is expanded to a time value or other
information. The escape sequences and their meanings are as
- follows; the braces denote optional portions.
+ follows; the brackets denote optional portions.
- '%%'
- A literal '%'.
+ ‘%%’
+ A literal ‘%’.
- '%[P][l]R'
+ ‘%[P][l]R’
The elapsed time in seconds.
- '%[P][l]U'
+ ‘%[P][l]U’
The number of CPU seconds spent in user mode.
- '%[P][l]S'
+ ‘%[P][l]S’
The number of CPU seconds spent in system mode.
- '%P'
+ ‘%P’
The CPU percentage, computed as (%U + %S) / %R.
The optional P is a digit specifying the precision, the number of
the decimal point may be specified; values of P greater than 6 are
changed to 6. If P is not specified, the value 3 is used.
- The optional 'l' specifies a longer format, including minutes, of
+ The optional ‘l’ specifies a longer format, including minutes, of
the form MMmSS.FFs. The value of P determines whether or not the
fraction is included.
If the value is null, Bash does not display any timing information.
A trailing newline is added when the format string is displayed.
-'TMOUT'
- If set to a value greater than zero, 'TMOUT' is treated as the
- default timeout for the 'read' builtin (*note Bash Builtins::).
- The 'select' command (*note Conditional Constructs::) terminates if
- input does not arrive after 'TMOUT' seconds when input is coming
+‘TMOUT’
+ If set to a value greater than zero, ‘TMOUT’ is treated as the
+ default timeout for the ‘read’ builtin (*note Bash Builtins::).
+ The ‘select’ command (*note Conditional Constructs::) terminates if
+ input does not arrive after ‘TMOUT’ seconds when input is coming
from a terminal.
In an interactive shell, the value is interpreted as the number of
prompt. Bash terminates after waiting for that number of seconds
if a complete line of input does not arrive.
-'TMPDIR'
+‘TMPDIR’
If set, Bash uses its value as the name of a directory in which
Bash creates temporary files for the shell's use.
-'UID'
+‘UID’
The numeric real user id of the current user. This variable is
readonly.
* Bash Startup Files:: When and how Bash executes scripts.
* Interactive Shells:: What an interactive shell is.
* Bash Conditional Expressions:: Primitives used in composing expressions for
- the 'test' builtin.
+ the ‘test’ builtin.
* Shell Arithmetic:: Arithmetic on shell variables.
* Aliases:: Substituting one command for another.
* Arrays:: Array Variables.
bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o OPTION]
[-O SHOPT_OPTION] [ARGUMENT ...]
- All of the single-character options used with the 'set' builtin
+ All of the single-character options used with the ‘set’ builtin
(*note The Set Builtin::) can be used as options when the shell is
invoked. In addition, there are several multi-character options that
you can use. These options must appear on the command line before the
single-character options to be recognized.
-'--debugger'
+‘--debugger’
Arrange for the debugger profile to be executed before the shell
starts. Turns on extended debugging mode (see *note The Shopt
- Builtin:: for a description of the 'extdebug' option to the 'shopt'
+ Builtin:: for a description of the ‘extdebug’ option to the ‘shopt’
builtin).
-'--dump-po-strings'
- A list of all double-quoted strings preceded by '$' is printed on
- the standard output in the GNU 'gettext' PO (portable object) file
- format. Equivalent to '-D' except for the output format.
+‘--dump-po-strings’
+ A list of all double-quoted strings preceded by ‘$’ is printed on
+ the standard output in the GNU ‘gettext’ PO (portable object) file
+ format. Equivalent to ‘-D’ except for the output format.
-'--dump-strings'
- Equivalent to '-D'.
+‘--dump-strings’
+ Equivalent to ‘-D’.
-'--help'
+‘--help’
Display a usage message on standard output and exit successfully.
-'--init-file FILENAME'
-'--rcfile FILENAME'
- Execute commands from FILENAME (instead of '~/.bashrc') in an
+‘--init-file FILENAME’
+‘--rcfile FILENAME’
+ Execute commands from FILENAME (instead of ‘~/.bashrc’) in an
interactive shell.
-'--login'
- Equivalent to '-l'.
+‘--login’
+ Equivalent to ‘-l’.
-'--noediting'
+‘--noediting’
Do not use the GNU Readline library (*note Command Line Editing::)
to read command lines when the shell is interactive.
-'--noprofile'
- Don't load the system-wide startup file '/etc/profile' or any of
- the personal initialization files '~/.bash_profile',
- '~/.bash_login', or '~/.profile' when Bash is invoked as a login
+‘--noprofile’
+ Don't load the system-wide startup file ‘/etc/profile’ or any of
+ the personal initialization files ‘~/.bash_profile’,
+ ‘~/.bash_login’, or ‘~/.profile’ when Bash is invoked as a login
shell.
-'--norc'
- Don't read the '~/.bashrc' initialization file in an interactive
- shell. This is on by default if the shell is invoked as 'sh'.
+‘--norc’
+ Don't read the ‘~/.bashrc’ initialization file in an interactive
+ shell. This is on by default if the shell is invoked as ‘sh’.
-'--posix'
+‘--posix’
Change the behavior of Bash where the default operation differs
from the POSIX standard to match the standard. This is intended to
make Bash behave as a strict superset of that standard. *Note Bash
POSIX Mode::, for a description of the Bash POSIX mode.
-'--restricted'
- Equivalent to '-r'. Make the shell a restricted shell (*note The
+‘--restricted’
+ Equivalent to ‘-r’. Make the shell a restricted shell (*note The
Restricted Shell::).
-'--verbose'
- Equivalent to '-v'. Print shell input lines as they're read.
+‘--verbose’
+ Equivalent to ‘-v’. Print shell input lines as they're read.
-'--version'
+‘--version’
Show version information for this instance of Bash on the standard
output and exit successfully.
There are several single-character options that may be supplied at
-invocation which are not available with the 'set' builtin.
+invocation which are not available with the ‘set’ builtin.
-'-c'
+‘-c’
Read and execute commands from the first non-option argument
COMMAND_STRING, then exit. If there are arguments after the
- COMMAND_STRING, the first argument is assigned to '$0' and any
+ COMMAND_STRING, the first argument is assigned to ‘$0’ and any
remaining arguments are assigned to the positional parameters. The
- assignment to '$0' sets the name of the shell, which is used in
+ assignment to ‘$0’ sets the name of the shell, which is used in
warning and error messages.
-'-i'
+‘-i’
Force the shell to run interactively. Interactive shells are
described in *note Interactive Shells::.
-'-l'
+‘-l’
Make this shell act as if it had been directly invoked by login.
When the shell is interactive, this is equivalent to starting a
- login shell with 'exec -l bash'. When the shell is not
- interactive, the login shell startup files will be executed. 'exec
- bash -l' or 'exec bash --login' will replace the current shell with
+ login shell with ‘exec -l bash’. When the shell is not
+ interactive, the login shell startup files will be executed. ‘exec
+ bash -l’ or ‘exec bash --login’ will replace the current shell with
a Bash login shell. *Note Bash Startup Files::, for a description
of the special behavior of a login shell.
-'-r'
+‘-r’
Make the shell a restricted shell (*note The Restricted Shell::).
-'-s'
+‘-s’
If this option is present, or if no arguments remain after option
processing, then commands are read from the standard input. This
option allows the positional parameters to be set when invoking an
interactive shell or when reading input through a pipe.
-'-D'
- A list of all double-quoted strings preceded by '$' is printed on
+‘-D’
+ A list of all double-quoted strings preceded by ‘$’ is printed on
the standard output. These are the strings that are subject to
- language translation when the current locale is not 'C' or 'POSIX'
- (*note Locale Translation::). This implies the '-n' option; no
+ language translation when the current locale is not ‘C’ or ‘POSIX’
+ (*note Locale Translation::). This implies the ‘-n’ option; no
commands will be executed.
-'[-+]O [SHOPT_OPTION]'
- SHOPT_OPTION is one of the shell options accepted by the 'shopt'
+‘[-+]O [SHOPT_OPTION]’
+ SHOPT_OPTION is one of the shell options accepted by the ‘shopt’
builtin (*note The Shopt Builtin::). If SHOPT_OPTION is present,
- '-O' sets the value of that option; '+O' unsets it. If
+ ‘-O’ sets the value of that option; ‘+O’ unsets it. If
SHOPT_OPTION is not supplied, the names and values of the shell
- options accepted by 'shopt' are printed on the standard output. If
- the invocation option is '+O', the output is displayed in a format
+ options accepted by ‘shopt’ are printed on the standard output. If
+ the invocation option is ‘+O’, the output is displayed in a format
that may be reused as input.
-'--'
- A '--' signals the end of options and disables further option
- processing. Any arguments after the '--' are treated as a shell
+‘--’
+ A ‘--’ signals the end of options and disables further option
+ processing. Any arguments after the ‘--’ are treated as a shell
script filename (*note Shell Scripts::) and arguments passed to
that script.
-'-'
- Equivalent to '--'.
+‘-’
+ Equivalent to ‘--’.
- A _login_ shell is one whose first character of argument zero is '-',
-or one invoked with the '--login' option.
+ A _login_ shell is one whose first character of argument zero is ‘-’,
+or one invoked with the ‘--login’ option.
An _interactive_ shell is one started without non-option arguments,
-unless '-s' is specified, without specifying the '-c' option, and whose
+unless ‘-s’ is specified, without specifying the ‘-c’ option, and whose
input and output are both connected to terminals (as determined by
-'isatty(3)'), or one started with the '-i' option. *Note Interactive
+‘isatty(3)’), or one started with the ‘-i’ option. *Note Interactive
Shells::, for more information.
- If arguments remain after option processing, and neither the '-c' nor
-the '-s' option has been supplied, the first argument is assumed to be
+ If arguments remain after option processing, and neither the ‘-c’ nor
+the ‘-s’ option has been supplied, the first argument is assumed to be
the name of a file containing shell commands (*note Shell Scripts::).
-When Bash is invoked in this fashion, '$0' is set to the name of the
+When Bash is invoked in this fashion, ‘$0’ is set to the name of the
file, and the positional parameters are set to the remaining arguments.
Bash reads and executes commands from this file, then exits. Bash's
exit status is the exit status of the last command executed in the
Interactive shells are described in *note Interactive Shells::.
-Invoked as an interactive login shell, or with '--login'
+Invoked as an interactive login shell, or with ‘--login’
........................................................
When Bash is invoked as an interactive login shell, or as a
-non-interactive shell with the '--login' option, it first reads and
-executes commands from the file '/etc/profile', if that file exists.
-After reading that file, it looks for '~/.bash_profile',
-'~/.bash_login', and '~/.profile', in that order, and reads and executes
+non-interactive shell with the ‘--login’ option, it first reads and
+executes commands from the file ‘/etc/profile’, if that file exists.
+After reading that file, it looks for ‘~/.bash_profile’,
+‘~/.bash_login’, and ‘~/.profile’, in that order, and reads and executes
commands from the first one that exists and is readable. The
-'--noprofile' option may be used when the shell is started to inhibit
+‘--noprofile’ option may be used when the shell is started to inhibit
this behavior.
When an interactive login shell exits, or a non-interactive login
-shell executes the 'exit' builtin command, Bash reads and executes
-commands from the file '~/.bash_logout', if it exists.
+shell executes the ‘exit’ builtin command, Bash reads and executes
+commands from the file ‘~/.bash_logout’, if it exists.
Invoked as an interactive non-login shell
.........................................
When an interactive shell that is not a login shell is started, Bash
-reads and executes commands from '~/.bashrc', if that file exists. This
-may be inhibited by using the '--norc' option. The '--rcfile FILE'
+reads and executes commands from ‘~/.bashrc’, if that file exists. This
+may be inhibited by using the ‘--norc’ option. The ‘--rcfile FILE’
option will force Bash to read and execute commands from FILE instead of
-'~/.bashrc'.
+‘~/.bashrc’.
- So, typically, your '~/.bash_profile' contains the line
+ So, typically, your ‘~/.bash_profile’ contains the line
if [ -f ~/.bashrc ]; then . ~/.bashrc; fi
after (or before) any login-specific initializations.
.........................
When Bash is started non-interactively, to run a shell script, for
-example, it looks for the variable 'BASH_ENV' in the environment,
+example, it looks for the variable ‘BASH_ENV’ in the environment,
expands its value if it appears there, and uses the expanded value as
the name of a file to read and execute. Bash behaves as if the
following command were executed:
if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
-but the value of the 'PATH' variable is not used to search for the
+but the value of the ‘PATH’ variable is not used to search for the
filename.
As noted above, if a non-interactive shell is invoked with the
-'--login' option, Bash attempts to read and execute commands from the
+‘--login’ option, Bash attempts to read and execute commands from the
login shell startup files.
-Invoked with name 'sh'
+Invoked with name ‘sh’
......................
-If Bash is invoked with the name 'sh', it tries to mimic the startup
-behavior of historical versions of 'sh' as closely as possible, while
+If Bash is invoked with the name ‘sh’, it tries to mimic the startup
+behavior of historical versions of ‘sh’ as closely as possible, while
conforming to the POSIX standard as well.
When invoked as an interactive login shell, or as a non-interactive
-shell with the '--login' option, it first attempts to read and execute
-commands from '/etc/profile' and '~/.profile', in that order. The
-'--noprofile' option may be used to inhibit this behavior. When invoked
-as an interactive shell with the name 'sh', Bash looks for the variable
-'ENV', expands its value if it is defined, and uses the expanded value
+shell with the ‘--login’ option, it first attempts to read and execute
+commands from ‘/etc/profile’ and ‘~/.profile’, in that order. The
+‘--noprofile’ option may be used to inhibit this behavior. When invoked
+as an interactive shell with the name ‘sh’, Bash looks for the variable
+‘ENV’, expands its value if it is defined, and uses the expanded value
as the name of a file to read and execute. Since a shell invoked as
-'sh' does not attempt to read and execute commands from any other
-startup files, the '--rcfile' option has no effect. A non-interactive
-shell invoked with the name 'sh' does not attempt to read any other
+‘sh’ does not attempt to read and execute commands from any other
+startup files, the ‘--rcfile’ option has no effect. A non-interactive
+shell invoked with the name ‘sh’ does not attempt to read any other
startup files.
- When invoked as 'sh', Bash enters POSIX mode after the startup files
+ When invoked as ‘sh’, Bash enters POSIX mode after the startup files
are read.
Invoked in POSIX mode
.....................
-When Bash is started in POSIX mode, as with the '--posix' command line
+When Bash is started in POSIX mode, as with the ‘--posix’ command line
option, it follows the POSIX standard for startup files. In this mode,
-interactive shells expand the 'ENV' variable and commands are read and
+interactive shells expand the ‘ENV’ variable and commands are read and
executed from the file whose name is the expanded value. No other
startup files are read.
Bash attempts to determine when it is being run with its standard input
connected to a network connection, as when executed by the historical
-remote shell daemon, usually 'rshd', or the secure shell daemon 'sshd'.
+remote shell daemon, usually ‘rshd’, or the secure shell daemon ‘sshd’.
If Bash determines it is being run non-interactively in this fashion, it
-reads and executes commands from '~/.bashrc', if that file exists and is
-readable. It will not do this if invoked as 'sh'. The '--norc' option
-may be used to inhibit this behavior, and the '--rcfile' option may be
-used to force another file to be read, but neither 'rshd' nor 'sshd'
+reads and executes commands from ‘~/.bashrc’, if that file exists and is
+readable. It will not do this if invoked as ‘sh’. The ‘--norc’ option
+may be used to inhibit this behavior, and the ‘--rcfile’ option may be
+used to force another file to be read, but neither ‘rshd’ nor ‘sshd’
generally invoke the shell with those options or allow them to be
specified.
................................................
If Bash is started with the effective user (group) id not equal to the
-real user (group) id, and the '-p' option is not supplied, no startup
+real user (group) id, and the ‘-p’ option is not supplied, no startup
files are read, shell functions are not inherited from the environment,
-the 'SHELLOPTS', 'BASHOPTS', 'CDPATH', and 'GLOBIGNORE' variables, if
+the ‘SHELLOPTS’, ‘BASHOPTS’, ‘CDPATH’, and ‘GLOBIGNORE’ variables, if
they appear in the environment, are ignored, and the effective user id
-is set to the real user id. If the '-p' option is supplied at
+is set to the real user id. If the ‘-p’ option is supplied at
invocation, the startup behavior is the same, but the effective user id
is not reset.
-----------------------------------
An interactive shell is one started without non-option arguments (unless
-'-s' is specified) and without specifying the '-c' option, whose input
+‘-s’ is specified) and without specifying the ‘-c’ option, whose input
and error output are both connected to terminals (as determined by
-'isatty(3)'), or one started with the '-i' option.
+‘isatty(3)’), or one started with the ‘-i’ option.
An interactive shell generally reads from and writes to a user's
terminal.
- The '-s' invocation option may be used to set the positional
+ The ‘-s’ invocation option may be used to set the positional
parameters when an interactive shell is started.
\1f
--------------------------------
To determine within a startup script whether or not Bash is running
-interactively, test the value of the '-' special parameter. It contains
-'i' when the shell is interactive. For example:
+interactively, test the value of the ‘-’ special parameter. It contains
+‘i’ when the shell is interactive. For example:
case "$-" in
*i*) echo This shell is interactive ;;
*) echo This shell is not interactive ;;
esac
- Alternatively, startup scripts may examine the variable 'PS1'; it is
+ Alternatively, startup scripts may examine the variable ‘PS1’; it is
unset in non-interactive shells, and set in interactive shells. Thus:
if [ -z "$PS1" ]; then
2. Job Control (*note Job Control::) is enabled by default. When job
control is in effect, Bash ignores the keyboard-generated job
- control signals 'SIGTTIN', 'SIGTTOU', and 'SIGTSTP'.
+ control signals ‘SIGTTIN’, ‘SIGTTOU’, and ‘SIGTSTP’.
- 3. Bash expands and displays 'PS1' before reading the first line of a
- command, and expands and displays 'PS2' before reading the second
+ 3. Bash expands and displays ‘PS1’ before reading the first line of a
+ command, and expands and displays ‘PS2’ before reading the second
and subsequent lines of a multi-line command. Bash expands and
- displays 'PS0' after it reads a command but before executing it.
+ displays ‘PS0’ after it reads a command but before executing it.
See *note Controlling the Prompt::, for a complete list of prompt
string escape sequences.
4. Bash executes the values of the set elements of the
- 'PROMPT_COMMAND' array variable as commands before printing the
- primary prompt, '$PS1' (*note Bash Variables::).
+ ‘PROMPT_COMMAND’ array variable as commands before printing the
+ primary prompt, ‘$PS1’ (*note Bash Variables::).
5. Readline (*note Command Line Editing::) is used to read commands
from the user's terminal.
- 6. Bash inspects the value of the 'ignoreeof' option to 'set -o'
- instead of exiting immediately when it receives an 'EOF' on its
+ 6. Bash inspects the value of the ‘ignoreeof’ option to ‘set -o’
+ instead of exiting immediately when it receives an ‘EOF’ on its
standard input when reading a command (*note The Set Builtin::).
7. Command history (*note Bash History Facilities::) and history
expansion (*note History Interaction::) are enabled by default.
- Bash will save the command history to the file named by '$HISTFILE'
+ Bash will save the command history to the file named by ‘$HISTFILE’
when a shell with history enabled exits.
8. Alias expansion (*note Aliases::) is performed by default.
- 9. In the absence of any traps, Bash ignores 'SIGTERM' (*note
+ 9. In the absence of any traps, Bash ignores ‘SIGTERM’ (*note
Signals::).
- 10. In the absence of any traps, 'SIGINT' is caught and handled (*note
- Signals::). 'SIGINT' will interrupt some shell builtins.
+ 10. In the absence of any traps, ‘SIGINT’ is caught and handled (*note
+ Signals::). ‘SIGINT’ will interrupt some shell builtins.
- 11. An interactive login shell sends a 'SIGHUP' to all jobs on exit if
- the 'huponexit' shell option has been enabled (*note Signals::).
+ 11. An interactive login shell sends a ‘SIGHUP’ to all jobs on exit if
+ the ‘huponexit’ shell option has been enabled (*note Signals::).
- 12. The '-n' invocation option is ignored, and 'set -n' has no effect
+ 12. The ‘-n’ invocation option is ignored, and ‘set -n’ has no effect
(*note The Set Builtin::).
13. Bash will check for mail periodically, depending on the values of
- the 'MAIL', 'MAILPATH', and 'MAILCHECK' shell variables (*note Bash
+ the ‘MAIL’, ‘MAILPATH’, and ‘MAILCHECK’ shell variables (*note Bash
Variables::).
14. Expansion errors due to references to unbound shell variables
- after 'set -u' has been enabled will not cause the shell to exit
+ after ‘set -u’ has been enabled will not cause the shell to exit
(*note The Set Builtin::).
15. The shell will not exit on expansion errors caused by VAR being
- unset or null in '${VAR:?WORD}' expansions (*note Shell Parameter
+ unset or null in ‘${VAR:?WORD}’ expansions (*note Shell Parameter
Expansion::).
16. Redirection errors encountered by shell builtins will not cause
17. When running in POSIX mode, a special builtin returning an error
status will not cause the shell to exit (*note Bash POSIX Mode::).
- 18. A failed 'exec' will not cause the shell to exit (*note Bourne
+ 18. A failed ‘exec’ will not cause the shell to exit (*note Bourne
Shell Builtins::).
19. Parser syntax errors will not cause the shell to exit.
- 20. If the 'cdspell' shell option is enabled, the shell will attempt
- simple spelling correction for directory arguments to the 'cd'
- builtin (see the description of the 'cdspell' option to the 'shopt'
- builtin in *note The Shopt Builtin::). The 'cdspell' option is
+ 20. If the ‘cdspell’ shell option is enabled, the shell will attempt
+ simple spelling correction for directory arguments to the ‘cd’
+ builtin (see the description of the ‘cdspell’ option to the ‘shopt’
+ builtin in *note The Shopt Builtin::). The ‘cdspell’ option is
only effective in interactive shells.
- 21. The shell will check the value of the 'TMOUT' variable and exit if
+ 21. The shell will check the value of the ‘TMOUT’ variable and exit if
a command is not read within the specified number of seconds after
- printing '$PS1' (*note Bash Variables::).
+ printing ‘$PS1’ (*note Bash Variables::).
\1f
File: bashref.info, Node: Bash Conditional Expressions, Next: Shell Arithmetic, Prev: Interactive Shells, Up: Bash Features
6.4 Bash Conditional Expressions
================================
-Conditional expressions are used by the '[[' compound command (*note
-Conditional Constructs::) and the 'test' and '[' builtin commands (*note
-Bourne Shell Builtins::). The 'test' and '[' commands determine their
+Conditional expressions are used by the ‘[[’ compound command (*note
+Conditional Constructs::) and the ‘test’ and ‘[’ builtin commands (*note
+Bourne Shell Builtins::). The ‘test’ and ‘[’ commands determine their
behavior based on the number of arguments; see the descriptions of those
commands for any other command-specific actions.
expressions. If the operating system on which Bash is running provides
these special files, Bash will use them; otherwise it will emulate them
internally with this behavior: If the FILE argument to one of the
-primaries is of the form '/dev/fd/N', then file descriptor N is checked.
-If the FILE argument to one of the primaries is one of '/dev/stdin',
-'/dev/stdout', or '/dev/stderr', file descriptor 0, 1, or 2,
+primaries is of the form ‘/dev/fd/N’, then file descriptor N is checked.
+If the FILE argument to one of the primaries is one of ‘/dev/stdin’,
+‘/dev/stdout’, or ‘/dev/stderr’, file descriptor 0, 1, or 2,
respectively, is checked.
- When used with '[[', the '<' and '>' operators sort lexicographically
-using the current locale. The 'test' command uses ASCII ordering.
+ When used with ‘[[’, the ‘<’ and ‘>’ operators sort lexicographically
+using the current locale. The ‘test’ command uses ASCII ordering.
Unless otherwise specified, primaries that operate on files follow
symbolic links and operate on the target of the link, rather than the
link itself.
-'-a FILE'
+‘-a FILE’
True if FILE exists.
-'-b FILE'
+‘-b FILE’
True if FILE exists and is a block special file.
-'-c FILE'
+‘-c FILE’
True if FILE exists and is a character special file.
-'-d FILE'
+‘-d FILE’
True if FILE exists and is a directory.
-'-e FILE'
+‘-e FILE’
True if FILE exists.
-'-f FILE'
+‘-f FILE’
True if FILE exists and is a regular file.
-'-g FILE'
+‘-g FILE’
True if FILE exists and its set-group-id bit is set.
-'-h FILE'
+‘-h FILE’
True if FILE exists and is a symbolic link.
-'-k FILE'
+‘-k FILE’
True if FILE exists and its "sticky" bit is set.
-'-p FILE'
+‘-p FILE’
True if FILE exists and is a named pipe (FIFO).
-'-r FILE'
+‘-r FILE’
True if FILE exists and is readable.
-'-s FILE'
+‘-s FILE’
True if FILE exists and has a size greater than zero.
-'-t FD'
+‘-t FD’
True if file descriptor FD is open and refers to a terminal.
-'-u FILE'
+‘-u FILE’
True if FILE exists and its set-user-id bit is set.
-'-w FILE'
+‘-w FILE’
True if FILE exists and is writable.
-'-x FILE'
+‘-x FILE’
True if FILE exists and is executable.
-'-G FILE'
+‘-G FILE’
True if FILE exists and is owned by the effective group id.
-'-L FILE'
+‘-L FILE’
True if FILE exists and is a symbolic link.
-'-N FILE'
+‘-N FILE’
True if FILE exists and has been modified since it was last read.
-'-O FILE'
+‘-O FILE’
True if FILE exists and is owned by the effective user id.
-'-S FILE'
+‘-S FILE’
True if FILE exists and is a socket.
-'FILE1 -ef FILE2'
+‘FILE1 -ef FILE2’
True if FILE1 and FILE2 refer to the same device and inode numbers.
-'FILE1 -nt FILE2'
+‘FILE1 -nt FILE2’
True if FILE1 is newer (according to modification date) than FILE2,
or if FILE1 exists and FILE2 does not.
-'FILE1 -ot FILE2'
+‘FILE1 -ot FILE2’
True if FILE1 is older than FILE2, or if FILE2 exists and FILE1
does not.
-'-o OPTNAME'
+‘-o OPTNAME’
True if the shell option OPTNAME is enabled. The list of options
- appears in the description of the '-o' option to the 'set' builtin
+ appears in the description of the ‘-o’ option to the ‘set’ builtin
(*note The Set Builtin::).
-'-v VARNAME'
+‘-v VARNAME’
True if the shell variable VARNAME is set (has been assigned a
value). If VARNAME is an indexed array variable name subscripted
- by '@' or '*', this returns true if the array has any set elements.
- If VARNAME is an associative array variable name subscripted by '@'
- or '*', this returns true if an element with that key is set.
+ by ‘@’ or ‘*’, this returns true if the array has any set elements.
+ If VARNAME is an associative array variable name subscripted by ‘@’
+ or ‘*’, this returns true if an element with that key is set.
-'-R VARNAME'
+‘-R VARNAME’
True if the shell variable VARNAME is set and is a name reference.
-'-z STRING'
+‘-z STRING’
True if the length of STRING is zero.
-'-n STRING'
-'STRING'
+‘-n STRING’
+‘STRING’
True if the length of STRING is non-zero.
-'STRING1 == STRING2'
-'STRING1 = STRING2'
- True if the strings are equal. When used with the '[[' command,
+‘STRING1 == STRING2’
+‘STRING1 = STRING2’
+ True if the strings are equal. When used with the ‘[[’ command,
this performs pattern matching as described above (*note
Conditional Constructs::).
- '=' should be used with the 'test' command for POSIX conformance.
+ ‘=’ should be used with the ‘test’ command for POSIX conformance.
-'STRING1 != STRING2'
+‘STRING1 != STRING2’
True if the strings are not equal.
-'STRING1 < STRING2'
+‘STRING1 < STRING2’
True if STRING1 sorts before STRING2 lexicographically.
-'STRING1 > STRING2'
+‘STRING1 > STRING2’
True if STRING1 sorts after STRING2 lexicographically.
-'ARG1 OP ARG2'
- 'OP' is one of '-eq', '-ne', '-lt', '-le', '-gt', or '-ge'. These
+‘ARG1 OP ARG2’
+ ‘OP’ is one of ‘-eq’, ‘-ne’, ‘-lt’, ‘-le’, ‘-gt’, or ‘-ge’. These
arithmetic binary operators return true if ARG1 is equal to, not
equal to, less than, less than or equal to, greater than, or
greater than or equal to ARG2, respectively. ARG1 and ARG2 may be
- positive or negative integers. When used with the '[[' command,
+ positive or negative integers. When used with the ‘[[’ command,
ARG1 and ARG2 are evaluated as arithmetic expressions (*note Shell
Arithmetic::).
====================
The shell allows arithmetic expressions to be evaluated, as one of the
-shell expansions or by using the '((' compound command, the 'let'
-builtin, or the '-i' option to the 'declare' builtin.
+shell expansions or by using the ‘((’ compound command, the ‘let’
+builtin, or the ‘-i’ option to the ‘declare’ builtin.
Evaluation is done in fixed-width integers with no check for
overflow, though division by 0 is trapped and flagged as an error. The
levels of equal-precedence operators. The levels are listed in order of
decreasing precedence.
-'ID++ ID--'
+‘ID++ ID--’
variable post-increment and post-decrement
-'++ID --ID'
+‘++ID --ID’
variable pre-increment and pre-decrement
-'- +'
+‘- +’
unary minus and plus
-'! ~'
+‘! ~’
logical and bitwise negation
-'**'
+‘**’
exponentiation
-'* / %'
+‘* / %’
multiplication, division, remainder
-'+ -'
+‘+ -’
addition, subtraction
-'<< >>'
+‘<< >>’
left and right bitwise shifts
-'<= >= < >'
+‘<= >= < >’
comparison
-'== !='
+‘== !=’
equality and inequality
-'&'
+‘&’
bitwise AND
-'^'
+‘^’
bitwise exclusive OR
-'|'
+‘|’
bitwise OR
-'&&'
+‘&&’
logical AND
-'||'
+‘||’
logical OR
-'expr ? if-true-expr : if-false-expr'
+‘expr ? if-true-expr : if-false-expr’
conditional operator
-'= *= /= %= += -= <<= >>= &= ^= |='
+‘= *= /= %= += -= <<= >>= &= ^= |=’
assignment
-'expr1 , expr2'
+‘expr1 , expr2’
comma
Shell variables are allowed as operands; parameter expansion is
evaluates to 0 when referenced by name without using the parameter
expansion syntax. The value of a variable is evaluated as an arithmetic
expression when it is referenced, or when a variable which has been
-given the 'integer' attribute using 'declare -i' is assigned a value. A
-null value evaluates to 0. A shell variable need not have its 'integer'
+given the ‘integer’ attribute using ‘declare -i’ is assigned a value. A
+null value evaluates to 0. A shell variable need not have its ‘integer’
attribute turned on to be used in an expression.
Integer constants follow the C language definition, without suffixes
or character constants. Constants with a leading 0 are interpreted as
-octal numbers. A leading '0x' or '0X' denotes hexadecimal. Otherwise,
-numbers take the form [BASE'#']N, where the optional BASE is a decimal
+octal numbers. A leading ‘0x’ or ‘0X’ denotes hexadecimal. Otherwise,
+numbers take the form [BASE‘#’]N, where the optional BASE is a decimal
number between 2 and 64 representing the arithmetic base, and N is a
-number in that base. If BASE'#' is omitted, then base 10 is used. When
+number in that base. If BASE‘#’ is omitted, then base 10 is used. When
specifying N, if a non-digit is required, the digits greater than 9 are
-represented by the lowercase letters, the uppercase letters, '@', and
-'_', in that order. If BASE is less than or equal to 36, lowercase and
+represented by the lowercase letters, the uppercase letters, ‘@’, and
+‘_’, in that order. If BASE is less than or equal to 36, lowercase and
uppercase letters may be used interchangeably to represent numbers
between 10 and 35.
6.6 Aliases
===========
-"Aliases" allow a string to be substituted for a word that is in a
+“Aliases” allow a string to be substituted for a word that is in a
position in the input where it can be the first word of a simple
command. Aliases have names and corresponding values that are set and
-unset using the 'alias' and 'unalias' builtin commands (*note Shell
+unset using the ‘alias’ and ‘unalias’ builtin commands (*note Shell
Builtin Commands::).
If the shell reads an unquoted word in the right position, it checks
had been read instead of the word. The shell doesn't look at any
characters following the word before attempting alias substitution.
- The characters '/', '$', '`', '=' and any of the shell metacharacters
+ The characters ‘/’, ‘$’, ‘`’, ‘=’ and any of the shell metacharacters
or quoting characters listed above may not appear in an alias name. The
replacement text may contain any valid shell input, including shell
metacharacters. The first word of the replacement text is tested for
aliases, but a word that is identical to an alias being expanded is not
-expanded a second time. This means that one may alias 'ls' to '"ls
--F"', for instance, and Bash does not try to recursively expand the
+expanded a second time. This means that one may alias ‘ls’ to ‘"ls
+-F"’, for instance, and Bash does not try to recursively expand the
replacement text.
- If the last character of the alias value is a 'blank', then the next
+ If the last character of the alias value is a ‘blank’, then the next
command word following the alias is also checked for alias expansion.
- Aliases are created and listed with the 'alias' command, and removed
-with the 'unalias' command.
+ Aliases are created and listed with the ‘alias’ command, and removed
+with the ‘unalias’ command.
There is no mechanism for using arguments in the replacement text, as
-in 'csh'. If arguments are needed, use a shell function (*note Shell
+in ‘csh’. If arguments are needed, use a shell function (*note Shell
Functions::) instead.
Aliases are not expanded when the shell is not interactive, unless
-the 'expand_aliases' shell option is set using 'shopt' (*note The Shopt
+the ‘expand_aliases’ shell option is set using ‘shopt’ (*note The Shopt
Builtin::).
The rules concerning the definition and use of aliases are somewhat
executed, because a function definition is itself a command. As a
consequence, aliases defined in a function are not available until after
that function is executed. To be safe, always put alias definitions on
-a separate line, and do not use 'alias' in compound commands.
+a separate line, and do not use ‘alias’ in compound commands.
For almost every purpose, shell functions are preferred over aliases.
==========
Bash provides one-dimensional indexed and associative array variables.
-Any variable may be used as an indexed array; the 'declare' builtin will
+Any variable may be used as an indexed array; the ‘declare’ builtin will
explicitly declare an array. There is no maximum limit on the size of
an array, nor any requirement that members be indexed or assigned
contiguously. Indexed arrays are referenced using integers (including
Associative arrays are created using
declare -A NAME
- Attributes may be specified for an array variable using the 'declare'
-and 'readonly' builtins. Each attribute applies to all members of an
+ Attributes may be specified for an array variable using the ‘declare’
+and ‘readonly’ builtins. Each attribute applies to all members of an
array.
Arrays are assigned to using compound assignments of the form
NAME=(VALUE1 VALUE2 ... )
-where each VALUE may be of the form '[SUBSCRIPT]='STRING. Indexed array
+where each VALUE may be of the form ‘[SUBSCRIPT]=’STRING. Indexed array
assignments do not require anything but STRING. When assigning to
indexed arrays, if the optional subscript is supplied, that index is
assigned to; otherwise the index of the element assigned is the last
using key/value pairs, the keys may not be missing or empty; a final
missing value is treated like the empty string.
- This syntax is also accepted by the 'declare' builtin. Individual
-array elements may be assigned to using the 'NAME[SUBSCRIPT]=VALUE'
+ This syntax is also accepted by the ‘declare’ builtin. Individual
+array elements may be assigned to using the ‘NAME[SUBSCRIPT]=VALUE’
syntax introduced above.
When assigning to an indexed array, if NAME is subscripted by a
than the maximum index of NAME, so negative indices count back from the
end of the array, and an index of -1 references the last element.
- The '+=' operator will append to an array variable when assigning
+ The ‘+=’ operator will append to an array variable when assigning
using the compound assignment syntax; see *note Shell Parameters::
above.
- Any element of an array may be referenced using '${NAME[SUBSCRIPT]}'.
+ Any element of an array may be referenced using ‘${NAME[SUBSCRIPT]}’.
The braces are required to avoid conflicts with the shell's filename
-expansion operators. If the SUBSCRIPT is '@' or '*', the word expands
+expansion operators. If the SUBSCRIPT is ‘@’ or ‘*’, the word expands
to all members of the array NAME, unless otherwise noted in the
description of a builtin or word expansion. These subscripts differ
only when the word appears within double quotes. If the word is
-double-quoted, '${NAME[*]}' expands to a single word with the value of
-each array member separated by the first character of the 'IFS'
-variable, and '${NAME[@]}' expands each element of NAME to a separate
-word. When there are no array members, '${NAME[@]}' expands to nothing.
+double-quoted, ‘${NAME[*]}’ expands to a single word with the value of
+each array member separated by the first character of the ‘IFS’
+variable, and ‘${NAME[@]}’ expands each element of NAME to a separate
+word. When there are no array members, ‘${NAME[@]}’ expands to nothing.
If the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the original
word, and the expansion of the last parameter is joined with the last
part of the original word. This is analogous to the expansion of the
-special parameters '@' and '*'. '${#NAME[SUBSCRIPT]}' expands to the
-length of '${NAME[SUBSCRIPT]}'. If SUBSCRIPT is '@' or '*', the
+special parameters ‘@’ and ‘*’. ‘${#NAME[SUBSCRIPT]}’ expands to the
+length of ‘${NAME[SUBSCRIPT]}’. If SUBSCRIPT is ‘@’ or ‘*’, the
expansion is the number of elements in the array. If the SUBSCRIPT used
to reference an element of an indexed array evaluates to a number less
than zero, it is interpreted as relative to one greater than the maximum
It is possible to obtain the keys (indices) of an array as well as
the values. ${!NAME[@]} and ${!NAME[*]} expand to the indices assigned
in array variable NAME. The treatment when in double quotes is similar
-to the expansion of the special parameters '@' and '*' within double
+to the expansion of the special parameters ‘@’ and ‘*’ within double
quotes.
- The 'unset' builtin is used to destroy arrays. 'unset
-NAME[SUBSCRIPT]' destroys the array element at index SUBSCRIPT.
+ The ‘unset’ builtin is used to destroy arrays. ‘unset
+NAME[SUBSCRIPT]’ destroys the array element at index SUBSCRIPT.
Negative subscripts to indexed arrays are interpreted as described
above. Unsetting the last element of an array variable does not unset
-the variable. 'unset NAME', where NAME is an array, removes the entire
-array. 'unset NAME[SUBSCRIPT]' behaves differently depending on the
-array type when given a subscript of '*' or '@'. When NAME is an
-associative array, it removes the element with key '*' or '@'. If NAME
-is an indexed array, 'unset' removes all of the elements, but does not
+the variable. ‘unset NAME’, where NAME is an array, removes the entire
+array. ‘unset NAME[SUBSCRIPT]’ behaves differently depending on the
+array type when given a subscript of ‘*’ or ‘@’. When NAME is an
+associative array, it removes the element with key ‘*’ or ‘@’. If NAME
+is an indexed array, ‘unset’ removes all of the elements, but does not
remove the array itself.
When using a variable name with a subscript as an argument to a
-command, such as with 'unset', without using the word expansion syntax
+command, such as with ‘unset’, without using the word expansion syntax
described above, the argument is subject to the shell's filename
expansion. If filename expansion is not desired, the argument should be
quoted.
- The 'declare', 'local', and 'readonly' builtins each accept a '-a'
-option to specify an indexed array and a '-A' option to specify an
-associative array. If both options are supplied, '-A' takes precedence.
-The 'read' builtin accepts a '-a' option to assign a list of words read
+ The ‘declare’, ‘local’, and ‘readonly’ builtins each accept a ‘-a’
+option to specify an indexed array and a ‘-A’ option to specify an
+associative array. If both options are supplied, ‘-A’ takes precedence.
+The ‘read’ builtin accepts a ‘-a’ option to assign a list of words read
from the standard input to an array, and can read values from the
-standard input into individual array elements. The 'set' and 'declare'
+standard input into individual array elements. The ‘set’ and ‘declare’
builtins display array values in a way that allows them to be reused as
input.
the directory stack.
The directory stack is a list of recently-visited directories. The
-'pushd' builtin adds directories to the stack as it changes the current
-directory, and the 'popd' builtin removes specified directories from the
+‘pushd’ builtin adds directories to the stack as it changes the current
+directory, and the ‘popd’ builtin removes specified directories from the
stack and changes the current directory to the directory removed. The
-'dirs' builtin displays the contents of the directory stack. The
+‘dirs’ builtin displays the contents of the directory stack. The
current directory is always the "top" of the directory stack.
The contents of the directory stack are also visible as the value of
-the 'DIRSTACK' shell variable.
+the ‘DIRSTACK’ shell variable.
\1f
File: bashref.info, Node: Directory Stack Builtins, Up: The Directory Stack
6.8.1 Directory Stack Builtins
------------------------------
-'dirs'
+‘dirs’
dirs [-clpv] [+N | -N]
Display the list of currently remembered directories. Directories
- are added to the list with the 'pushd' command; the 'popd' command
+ are added to the list with the ‘pushd’ command; the ‘popd’ command
removes directories from the list. The current directory is always
the first directory in the stack.
- '-c'
+ ‘-c’
Clears the directory stack by deleting all of the elements.
- '-l'
+ ‘-l’
Produces a listing using full pathnames; the default listing
format uses a tilde to denote the home directory.
- '-p'
- Causes 'dirs' to print the directory stack with one entry per
+ ‘-p’
+ Causes ‘dirs’ to print the directory stack with one entry per
line.
- '-v'
- Causes 'dirs' to print the directory stack with one entry per
+ ‘-v’
+ Causes ‘dirs’ to print the directory stack with one entry per
line, prefixing each entry with its index in the stack.
- '+N'
+ ‘+N’
Displays the Nth directory (counting from the left of the list
- printed by 'dirs' when invoked without options), starting with
+ printed by ‘dirs’ when invoked without options), starting with
zero.
- '-N'
+ ‘-N’
Displays the Nth directory (counting from the right of the
- list printed by 'dirs' when invoked without options), starting
+ list printed by ‘dirs’ when invoked without options), starting
with zero.
-'popd'
+‘popd’
popd [-n] [+N | -N]
Removes elements from the directory stack. The elements are
- numbered from 0 starting at the first directory listed by 'dirs';
- that is, 'popd' is equivalent to 'popd +0'.
+ numbered from 0 starting at the first directory listed by ‘dirs’;
+ that is, ‘popd’ is equivalent to ‘popd +0’.
- When no arguments are given, 'popd' removes the top directory from
+ When no arguments are given, ‘popd’ removes the top directory from
the stack and changes to the new top directory.
Arguments, if supplied, have the following meanings:
- '-n'
+ ‘-n’
Suppresses the normal change of directory when removing
directories from the stack, so that only the stack is
manipulated.
- '+N'
+ ‘+N’
Removes the Nth directory (counting from the left of the list
- printed by 'dirs'), starting with zero, from the stack.
- '-N'
+ printed by ‘dirs’), starting with zero, from the stack.
+ ‘-N’
Removes the Nth directory (counting from the right of the list
- printed by 'dirs'), starting with zero, from the stack.
+ printed by ‘dirs’), starting with zero, from the stack.
- If the top element of the directory stack is modified, and the '-n'
- option was not supplied, 'popd' uses the 'cd' builtin to change to
- the directory at the top of the stack. If the 'cd' fails, 'popd'
+ If the top element of the directory stack is modified, and the ‘-n’
+ option was not supplied, ‘popd’ uses the ‘cd’ builtin to change to
+ the directory at the top of the stack. If the ‘cd’ fails, ‘popd’
returns a non-zero value.
- Otherwise, 'popd' returns an unsuccessful status if an invalid
+ Otherwise, ‘popd’ returns an unsuccessful status if an invalid
option is encountered, the directory stack is empty, or a
non-existent directory stack entry is specified.
- If the 'popd' command is successful, Bash runs 'dirs' to show the
+ If the ‘popd’ command is successful, Bash runs ‘dirs’ to show the
final contents of the directory stack, and the return status is 0.
-'pushd'
+‘pushd’
pushd [-n] [+N | -N | DIR]
Adds a directory to the top of the directory stack, or rotates the
stack, making the new top of the stack the current working
- directory. With no arguments, 'pushd' exchanges the top two
+ directory. With no arguments, ‘pushd’ exchanges the top two
elements of the directory stack.
Arguments, if supplied, have the following meanings:
- '-n'
+ ‘-n’
Suppresses the normal change of directory when rotating or
adding directories to the stack, so that only the stack is
manipulated.
- '+N'
+ ‘+N’
Brings the Nth directory (counting from the left of the list
- printed by 'dirs', starting with zero) to the top of the list
+ printed by ‘dirs’, starting with zero) to the top of the list
by rotating the stack.
- '-N'
+ ‘-N’
Brings the Nth directory (counting from the right of the list
- printed by 'dirs', starting with zero) to the top of the list
+ printed by ‘dirs’, starting with zero) to the top of the list
by rotating the stack.
- 'DIR'
+ ‘DIR’
Makes DIR be the top of the stack.
- After the stack has been modified, if the '-n' option was not
- supplied, 'pushd' uses the 'cd' builtin to change to the directory
- at the top of the stack. If the 'cd' fails, 'pushd' returns a
+ After the stack has been modified, if the ‘-n’ option was not
+ supplied, ‘pushd’ uses the ‘cd’ builtin to change to the directory
+ at the top of the stack. If the ‘cd’ fails, ‘pushd’ returns a
non-zero value.
- Otherwise, if no arguments are supplied, 'pushd' returns 0 unless
+ Otherwise, if no arguments are supplied, ‘pushd’ returns 0 unless
the directory stack is empty. When rotating the directory stack,
- 'pushd' returns 0 unless the directory stack is empty or a
+ ‘pushd’ returns 0 unless the directory stack is empty or a
non-existent directory stack element is specified.
- If the 'pushd' command is successful, Bash runs 'dirs' to show the
+ If the ‘pushd’ command is successful, Bash runs ‘dirs’ to show the
final contents of the directory stack.
\1f
6.9 Controlling the Prompt
==========================
-Bash examines the value of the array variable 'PROMPT_COMMAND' just
+Bash examines the value of the array variable ‘PROMPT_COMMAND’ just
before printing each primary prompt. If any elements in
-'PROMPT_COMMAND' are set and non-null, Bash executes each value, in
+‘PROMPT_COMMAND’ are set and non-null, Bash executes each value, in
numeric order, just as if it had been typed on the command line.
In addition, the following table describes the special characters
-which can appear in the prompt variables 'PS0', 'PS1', 'PS2', and 'PS4':
+which can appear in the prompt variables ‘PS0’, ‘PS1’, ‘PS2’, and ‘PS4’:
-'\a'
+‘\a’
A bell character.
-'\d'
+‘\d’
The date, in "Weekday Month Date" format (e.g., "Tue May 26").
-'\D{FORMAT}'
- The FORMAT is passed to 'strftime'(3) and the result is inserted
+‘\D{FORMAT}’
+ The FORMAT is passed to ‘strftime’(3) and the result is inserted
into the prompt string; an empty FORMAT results in a
locale-specific time representation. The braces are required.
-'\e'
+‘\e’
An escape character.
-'\h'
+‘\h’
The hostname, up to the first '.'.
-'\H'
+‘\H’
The hostname.
-'\j'
+‘\j’
The number of jobs currently managed by the shell.
-'\l'
+‘\l’
The basename of the shell's terminal device name.
-'\n'
+‘\n’
A newline.
-'\r'
+‘\r’
A carriage return.
-'\s'
- The name of the shell, the basename of '$0' (the portion following
+‘\s’
+ The name of the shell, the basename of ‘$0’ (the portion following
the final slash).
-'\t'
+‘\t’
The time, in 24-hour HH:MM:SS format.
-'\T'
+‘\T’
The time, in 12-hour HH:MM:SS format.
-'\@'
+‘\@’
The time, in 12-hour am/pm format.
-'\A'
+‘\A’
The time, in 24-hour HH:MM format.
-'\u'
+‘\u’
The username of the current user.
-'\v'
+‘\v’
The version of Bash (e.g., 2.00)
-'\V'
+‘\V’
The release of Bash, version + patchlevel (e.g., 2.00.0)
-'\w'
- The value of the 'PWD' shell variable ('$PWD'), with '$HOME'
- abbreviated with a tilde (uses the '$PROMPT_DIRTRIM' variable).
-'\W'
- The basename of '$PWD', with '$HOME' abbreviated with a tilde.
-'\!'
+‘\w’
+ The value of the ‘PWD’ shell variable (‘$PWD’), with ‘$HOME’
+ abbreviated with a tilde (uses the ‘$PROMPT_DIRTRIM’ variable).
+‘\W’
+ The basename of ‘$PWD’, with ‘$HOME’ abbreviated with a tilde.
+‘\!’
The history number of this command.
-'\#'
+‘\#’
The command number of this command.
-'\$'
- If the effective uid is 0, '#', otherwise '$'.
-'\NNN'
+‘\$’
+ If the effective uid is 0, ‘#’, otherwise ‘$’.
+‘\NNN’
The character whose ASCII code is the octal value NNN.
-'\\'
+‘\\’
A backslash.
-'\['
+‘\[’
Begin a sequence of non-printing characters. This could be used to
embed a terminal control sequence into the prompt.
-'\]'
+‘\]’
End a sequence of non-printing characters.
The command number and the history number are usually different: the
After the string is decoded, it is expanded via parameter expansion,
command substitution, arithmetic expansion, and quote removal, subject
-to the value of the 'promptvars' shell option (*note The Shopt
+to the value of the ‘promptvars’ shell option (*note The Shopt
Builtin::). This can have unwanted side effects if escaped portions of
the string appear within command substitution or contain characters
special to word expansion.
6.10 The Restricted Shell
=========================
-If Bash is started with the name 'rbash', or the '--restricted' or '-r'
+If Bash is started with the name ‘rbash’, or the ‘--restricted’ or ‘-r’
option is supplied at invocation, the shell becomes restricted. A
restricted shell is used to set up an environment more controlled than
-the standard shell. A restricted shell behaves identically to 'bash'
+the standard shell. A restricted shell behaves identically to ‘bash’
with the exception that the following are disallowed or not performed:
- * Changing directories with the 'cd' builtin.
- * Setting or unsetting the values of the 'SHELL', 'PATH', 'HISTFILE',
- 'ENV', or 'BASH_ENV' variables.
- * Specifying command names containing slashes.
- * Specifying a filename containing a slash as an argument to the '.'
+ • Changing directories with the ‘cd’ builtin.
+ • Setting or unsetting the values of the ‘SHELL’, ‘PATH’, ‘HISTFILE’,
+ ‘ENV’, or ‘BASH_ENV’ variables.
+ • Specifying command names containing slashes.
+ • Specifying a filename containing a slash as an argument to the ‘.’
builtin command.
- * Specifying a filename containing a slash as an argument to the
- 'history' builtin command.
- * Specifying a filename containing a slash as an argument to the '-p'
- option to the 'hash' builtin command.
- * Importing function definitions from the shell environment at
+ • Specifying a filename containing a slash as an argument to the
+ ‘history’ builtin command.
+ • Specifying a filename containing a slash as an argument to the ‘-p’
+ option to the ‘hash’ builtin command.
+ • Importing function definitions from the shell environment at
startup.
- * Parsing the value of 'SHELLOPTS' from the shell environment at
+ • Parsing the value of ‘SHELLOPTS’ from the shell environment at
startup.
- * Redirecting output using the '>', '>|', '<>', '>&', '&>', and '>>'
+ • Redirecting output using the ‘>’, ‘>|’, ‘<>’, ‘>&’, ‘&>’, and ‘>>’
redirection operators.
- * Using the 'exec' builtin to replace the shell with another command.
- * Adding or deleting builtin commands with the '-f' and '-d' options
- to the 'enable' builtin.
- * Using the 'enable' builtin command to enable disabled shell
+ • Using the ‘exec’ builtin to replace the shell with another command.
+ • Adding or deleting builtin commands with the ‘-f’ and ‘-d’ options
+ to the ‘enable’ builtin.
+ • Using the ‘enable’ builtin command to enable disabled shell
builtins.
- * Specifying the '-p' option to the 'command' builtin.
- * Turning off restricted mode with 'set +r' or 'shopt -u
- restricted_shell'.
+ • Specifying the ‘-p’ option to the ‘command’ builtin.
+ • Turning off restricted mode with ‘set +r’ or ‘shopt -u
+ restricted_shell’.
These restrictions are enforced after any startup files are read.
When a command that is found to be a shell script is executed (*note
-Shell Scripts::), 'rbash' turns off any restrictions in the shell
+Shell Scripts::), ‘rbash’ turns off any restrictions in the shell
spawned to execute the script.
The restricted shell mode is only one component of a useful
-restricted environment. It should be accompanied by setting 'PATH' to a
+restricted environment. It should be accompanied by setting ‘PATH’ to a
value that allows execution of only a few verified commands (commands
that allow shell escapes are particularly vulnerable), changing the
-current directory to a non-writable directory other than '$HOME' after
+current directory to a non-writable directory other than ‘$HOME’ after
login, not allowing the restricted shell to execute shell scripts, and
cleaning the environment of variables that cause some commands to modify
-their behavior (e.g., 'VISUAL' or 'PAGER').
+their behavior (e.g., ‘VISUAL’ or ‘PAGER’).
Modern systems provide more secure ways to implement a restricted
-environment, such as 'jails', 'zones', or 'containers'.
+environment, such as ‘jails’, ‘zones’, or ‘containers’.
\1f
File: bashref.info, Node: Bash POSIX Mode, Next: Shell Compatibility Mode, Prev: The Restricted Shell, Up: Bash Features
The special builtins, which must be implemented as part of the shell
to provide the desired functionality, are specified as being part of the
-shell; examples of these are 'eval' and 'export'. Other utilities
+shell; examples of these are ‘eval’ and ‘export’. Other utilities
appear in the sections of POSIX not devoted to the shell which are
commonly (and in some cases must be) implemented as builtin commands,
-such as 'read' and 'test'. POSIX also specifies aspects of the shell's
+such as ‘read’ and ‘test’. POSIX also specifies aspects of the shell's
interactive behavior, including job control and command line editing.
Only vi-style line editing commands have been standardized; emacs
editing commands were left out due to objections.
Although Bash is an implementation of the POSIX shell specification,
there are areas where the Bash default behavior differs from the
-specification. The Bash "posix mode" changes the Bash behavior in these
+specification. The Bash “posix mode” changes the Bash behavior in these
areas so that it conforms to the standard more closely.
- Starting Bash with the '--posix' command-line option or executing
-'set -o posix' while Bash is running will cause Bash to conform more
+ Starting Bash with the ‘--posix’ command-line option or executing
+‘set -o posix’ while Bash is running will cause Bash to conform more
closely to the POSIX standard by changing the behavior to match that
specified by POSIX in areas where the Bash default differs.
- When invoked as 'sh', Bash enters POSIX mode after reading the
+ When invoked as ‘sh’, Bash enters POSIX mode after reading the
startup files.
The following list is what's changed when 'POSIX mode' is in effect:
- 1. Bash ensures that the 'POSIXLY_CORRECT' variable is set.
+ 1. Bash ensures that the ‘POSIXLY_CORRECT’ variable is set.
2. When a command in the hash table no longer exists, Bash will
- re-search '$PATH' to find the new location. This is also available
- with 'shopt -s checkhash'.
+ re-search ‘$PATH’ to find the new location. This is also available
+ with ‘shopt -s checkhash’.
3. Bash will not insert a command without the execute bit set into the
command hash table, even if it returns it as a (last-ditch) result
- from a '$PATH' search.
+ from a ‘$PATH’ search.
4. The message printed by the job control code and builtins when a job
exits with a non-zero status is 'Done(status)'.
5. The message printed by the job control code and builtins when a job
is stopped is 'Stopped(SIGNAME)', where SIGNAME is, for example,
- 'SIGTSTP'.
+ ‘SIGTSTP’.
6. Alias expansion is always enabled, even in non-interactive shells.
the command substitution is initially parsed (e.g., as part of a
function definition).
- 9. The POSIX 'PS1' and 'PS2' expansions of '!' to the history number
- and '!!' to '!' are enabled, and parameter expansion is performed
- on the values of 'PS1' and 'PS2' regardless of the setting of the
- 'promptvars' option.
+ 9. The POSIX ‘PS1’ and ‘PS2’ expansions of ‘!’ to the history number
+ and ‘!!’ to ‘!’ are enabled, and parameter expansion is performed
+ on the values of ‘PS1’ and ‘PS2’ regardless of the setting of the
+ ‘promptvars’ option.
- 10. The POSIX startup files are executed ('$ENV') rather than the
+ 10. The POSIX startup files are executed (‘$ENV’) rather than the
normal Bash files.
11. Tilde expansion is only performed on assignments preceding a
command name, rather than on all assignment statements on the line.
- 12. The default history file is '~/.sh_history' (this is the default
- value the shell assigns to '$HISTFILE').
+ 12. The default history file is ‘~/.sh_history’ (this is the default
+ value the shell assigns to ‘$HISTFILE’).
13. Redirection operators do not perform filename expansion on the
word in the redirection unless the shell is interactive.
14. Redirection operators do not perform word splitting on the word in
the redirection.
- 15. Function names must be valid shell 'name's. That is, they may not
+ 15. Function names must be valid shell ‘name’s. That is, they may not
contain characters other than letters, digits, and underscores, and
may not start with a digit. Declaring a function with an invalid
name causes a fatal syntax error in non-interactive shells.
whose name contains one or more slashes.
18. POSIX special builtins are found before shell functions during
- command lookup, including output printed by the 'type' and
- 'command' builtins.
+ command lookup, including output printed by the ‘type’ and
+ ‘command’ builtins.
- 19. When printing shell function definitions (e.g., by 'type'), Bash
- does not print the 'function' keyword.
+ 19. When printing shell function definitions (e.g., by ‘type’), Bash
+ does not print the ‘function’ keyword.
20. Literal tildes that appear as the first character in elements of
- the 'PATH' variable are not expanded as described above under *note
+ the ‘PATH’ variable are not expanded as described above under *note
Tilde Expansion::.
- 21. The 'time' reserved word may be used by itself as a command. When
+ 21. The ‘time’ reserved word may be used by itself as a command. When
used in this way, it displays timing statistics for the shell and
- its completed children. The 'TIMEFORMAT' variable controls the
+ its completed children. The ‘TIMEFORMAT’ variable controls the
format of the timing information.
22. When parsing and expanding a ${...} expansion that appears within
the operator is one of those defined to perform pattern removal.
In this case, they do not have to appear as matched pairs.
- 23. The parser does not recognize 'time' as a reserved word if the
- next token begins with a '-'.
+ 23. The parser does not recognize ‘time’ as a reserved word if the
+ next token begins with a ‘-’.
- 24. The '!' character does not introduce history expansion within a
- double-quoted string, even if the 'histexpand' option is enabled.
+ 24. The ‘!’ character does not introduce history expansion within a
+ double-quoted string, even if the ‘histexpand’ option is enabled.
25. If a POSIX special builtin returns an error status, a
non-interactive shell exits. The fatal errors are those listed in
options, redirection errors, variable assignment errors for
assignments preceding the command name, and so on.
- 26. The 'unset' builtin with the '-v' option specified returns a fatal
- error if it attempts to unset a 'readonly' or 'non-unsettable'
+ 26. The ‘unset’ builtin with the ‘-v’ option specified returns a fatal
+ error if it attempts to unset a ‘readonly’ or ‘non-unsettable’
variable, or encounters a variable name argument that is an invalid
identifier, which causes a non-interactive shell to exit.
27. When asked to unset a variable that appears in an assignment
- statement preceding the command, the 'unset' builtin attempts to
+ statement preceding the command, the ‘unset’ builtin attempts to
unset a variable of the same name in the current or previous scope
as well. This implements the required "if an assigned variable is
further modified by the utility, the modifications made by the
occurred").
30. A non-interactive shell exits with an error status if the
- iteration variable in a 'for' statement or the selection variable
- in a 'select' statement is a readonly variable or has an invalid
+ iteration variable in a ‘for’ statement or the selection variable
+ in a ‘select’ statement is a readonly variable or has an invalid
name.
- 31. Non-interactive shells exit if FILENAME in '.' FILENAME is not
+ 31. Non-interactive shells exit if FILENAME in ‘.’ FILENAME is not
found.
32. Non-interactive shells exit if a syntax error in an arithmetic
33. Non-interactive shells exit if a parameter expansion error occurs.
34. Non-interactive shells exit if there is a syntax error in a script
- read with the '.' or 'source' builtins, or in a string processed by
- the 'eval' builtin.
+ read with the ‘.’ or ‘source’ builtins, or in a string processed by
+ the ‘eval’ builtin.
35. While variable indirection is available, it may not be applied to
- the '#' and '?' special parameters.
+ the ‘#’ and ‘?’ special parameters.
- 36. Expanding the '*' special parameter in a pattern context where the
- expansion is double-quoted does not treat the '$*' as if it were
+ 36. Expanding the ‘*’ special parameter in a pattern context where the
+ expansion is double-quoted does not treat the ‘$*’ as if it were
double-quoted.
37. Assignment statements preceding POSIX special builtins persist in
the shell environment after the builtin completes.
- 38. The 'command' builtin does not prevent builtins that take
+ 38. The ‘command’ builtin does not prevent builtins that take
assignment statements as arguments from expanding them as
assignment statements; when not in POSIX mode, assignment builtins
lose their assignment statement expansion properties when preceded
- by 'command'.
+ by ‘command’.
- 39. The 'bg' builtin uses the required format to describe each job
+ 39. The ‘bg’ builtin uses the required format to describe each job
placed in the background, which does not include an indication of
whether the job is the current or previous job.
- 40. The output of 'kill -l' prints all the signal names on a single
- line, separated by spaces, without the 'SIG' prefix.
+ 40. The output of ‘kill -l’ prints all the signal names on a single
+ line, separated by spaces, without the ‘SIG’ prefix.
- 41. The 'kill' builtin does not accept signal names with a 'SIG'
+ 41. The ‘kill’ builtin does not accept signal names with a ‘SIG’
prefix.
- 42. The 'export' and 'readonly' builtin commands display their output
+ 42. The ‘export’ and ‘readonly’ builtin commands display their output
in the format required by POSIX.
- 43. If the 'export' and 'readonly' builtin commands get an argument
+ 43. If the ‘export’ and ‘readonly’ builtin commands get an argument
that is not a valid identifier, and they are not operating on shell
functions, they return an error. This will cause a non-interactive
shell to exit because these are special builtins.
- 44. The 'trap' builtin displays signal names without the leading
- 'SIG'.
+ 44. The ‘trap’ builtin displays signal names without the leading
+ ‘SIG’.
- 45. The 'trap' builtin doesn't check the first argument for a possible
+ 45. The ‘trap’ builtin doesn't check the first argument for a possible
signal specification and revert the signal handling to the original
disposition if it is, unless that argument consists solely of
digits and is a valid signal number. If users want to reset the
handler for a given signal to the original disposition, they should
- use '-' as the first argument.
+ use ‘-’ as the first argument.
- 46. 'trap -p' without arguments displays signals whose dispositions
+ 46. ‘trap -p’ without arguments displays signals whose dispositions
are set to SIG_DFL and those that were ignored when the shell
started, not just trapped signals.
- 47. The '.' and 'source' builtins do not search the current directory
- for the filename argument if it is not found by searching 'PATH'.
+ 47. The ‘.’ and ‘source’ builtins do not search the current directory
+ for the filename argument if it is not found by searching ‘PATH’.
48. Enabling POSIX mode has the effect of setting the
- 'inherit_errexit' option, so subshells spawned to execute command
- substitutions inherit the value of the '-e' option from the parent
- shell. When the 'inherit_errexit' option is not enabled, Bash
- clears the '-e' option in such subshells.
+ ‘inherit_errexit’ option, so subshells spawned to execute command
+ substitutions inherit the value of the ‘-e’ option from the parent
+ shell. When the ‘inherit_errexit’ option is not enabled, Bash
+ clears the ‘-e’ option in such subshells.
- 49. Enabling POSIX mode has the effect of setting the 'shift_verbose'
- option, so numeric arguments to 'shift' that exceed the number of
+ 49. Enabling POSIX mode has the effect of setting the ‘shift_verbose’
+ option, so numeric arguments to ‘shift’ that exceed the number of
positional parameters will result in an error message.
- 50. When the 'alias' builtin displays alias definitions, it does not
- display them with a leading 'alias ' unless the '-p' option is
+ 50. When the ‘alias’ builtin displays alias definitions, it does not
+ display them with a leading ‘alias ’ unless the ‘-p’ option is
supplied.
- 51. When the 'set' builtin is invoked without options, it does not
+ 51. When the ‘set’ builtin is invoked without options, it does not
display shell function names and definitions.
- 52. When the 'set' builtin is invoked without options, it displays
+ 52. When the ‘set’ builtin is invoked without options, it displays
variable values without quotes, unless they contain shell
metacharacters, even if the result contains nonprinting characters.
- 53. When the 'cd' builtin is invoked in logical mode, and the pathname
- constructed from '$PWD' and the directory name supplied as an
- argument does not refer to an existing directory, 'cd' will fail
+ 53. When the ‘cd’ builtin is invoked in logical mode, and the pathname
+ constructed from ‘$PWD’ and the directory name supplied as an
+ argument does not refer to an existing directory, ‘cd’ will fail
instead of falling back to physical mode.
- 54. When the 'cd' builtin cannot change a directory because the length
- of the pathname constructed from '$PWD' and the directory name
- supplied as an argument exceeds 'PATH_MAX' when all symbolic links
- are expanded, 'cd' will fail instead of attempting to use only the
+ 54. When the ‘cd’ builtin cannot change a directory because the length
+ of the pathname constructed from ‘$PWD’ and the directory name
+ supplied as an argument exceeds ‘PATH_MAX’ when all symbolic links
+ are expanded, ‘cd’ will fail instead of attempting to use only the
supplied directory name.
- 55. The 'pwd' builtin verifies that the value it prints is the same as
+ 55. The ‘pwd’ builtin verifies that the value it prints is the same as
the current directory, even if it is not asked to check the file
- system with the '-P' option.
+ system with the ‘-P’ option.
- 56. When listing the history, the 'fc' builtin does not include an
+ 56. When listing the history, the ‘fc’ builtin does not include an
indication of whether or not a history entry has been modified.
- 57. The default editor used by 'fc' is 'ed'.
+ 57. The default editor used by ‘fc’ is ‘ed’.
- 58. If there are too many arguments supplied to 'fc -s', 'fc' prints
+ 58. If there are too many arguments supplied to ‘fc -s’, ‘fc’ prints
an error message and returns failure.
- 59. The 'type' and 'command' builtins will not report a non-executable
+ 59. The ‘type’ and ‘command’ builtins will not report a non-executable
file as having been found, though the shell will attempt to execute
- such a file if it is the only so-named file found in '$PATH'.
+ such a file if it is the only so-named file found in ‘$PATH’.
- 60. The 'vi' editing mode will invoke the 'vi' editor directly when
- the 'v' command is run, instead of checking '$VISUAL' and
- '$EDITOR'.
+ 60. The ‘vi’ editing mode will invoke the ‘vi’ editor directly when
+ the ‘v’ command is run, instead of checking ‘$VISUAL’ and
+ ‘$EDITOR’.
- 61. When the 'xpg_echo' option is enabled, Bash does not attempt to
- interpret any arguments to 'echo' as options. Each argument is
+ 61. When the ‘xpg_echo’ option is enabled, Bash does not attempt to
+ interpret any arguments to ‘echo’ as options. Each argument is
displayed, after escape characters are converted.
- 62. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
- and '-f' options.
+ 62. The ‘ulimit’ builtin uses a block size of 512 bytes for the ‘-c’
+ and ‘-f’ options.
- 63. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
- interrupt the 'wait' builtin and cause it to return immediately.
+ 63. The arrival of ‘SIGCHLD’ when a trap is set on ‘SIGCHLD’ does not
+ interrupt the ‘wait’ builtin and cause it to return immediately.
The trap command is run once for each child that exits.
- 64. The 'read' builtin may be interrupted by a signal for which a trap
+ 64. The ‘read’ builtin may be interrupted by a signal for which a trap
has been set. If Bash receives a trapped signal while executing
- 'read', the trap handler executes and 'read' returns an exit status
+ ‘read’, the trap handler executes and ‘read’ returns an exit status
greater than 128.
- 65. The 'printf' builtin uses 'double' (via 'strtod') to convert
+ 65. The ‘printf’ builtin uses ‘double’ (via ‘strtod’) to convert
arguments corresponding to floating point conversion specifiers,
- instead of 'long double' if it's available. The 'L' length
- modifier forces 'printf' to use 'long double' if it's available.
+ instead of ‘long double’ if it's available. The ‘L’ length
+ modifier forces ‘printf’ to use ‘long double’ if it's available.
66. Bash removes an exited background process's status from the list
- of such statuses after the 'wait' builtin is used to obtain it.
+ of such statuses after the ‘wait’ builtin is used to obtain it.
- 67. A double quote character ('"') is treated specially when it
+ 67. A double quote character (‘"’) is treated specially when it
appears in a backquoted command substitution in the body of a
here-document that undergoes expansion. That means, for example,
that a backslash preceding a double quote character will escape it
and the backslash will be removed.
- 68. The 'test' builtin compares strings using the current locale when
- processing the '<' and '>' binary operators.
+ 68. The ‘test’ builtin compares strings using the current locale when
+ processing the ‘<’ and ‘>’ binary operators.
- 69. The 'test' builtin's '-t' unary primary requires an argument.
- Historical versions of 'test' made the argument optional in certain
+ 69. The ‘test’ builtin's ‘-t’ unary primary requires an argument.
+ Historical versions of ‘test’ made the argument optional in certain
cases, and Bash attempts to accommodate those for backwards
compatibility.
- 70. Command substitutions don't set the '?' special parameter. The
+ 70. Command substitutions don't set the ‘?’ special parameter. The
exit status of a simple command without a command word is still the
exit status of the last command substitution that occurred while
evaluating the variable assignments and redirections in that
There is other POSIX behavior that Bash does not implement by default
even when in POSIX mode. Specifically:
- 1. The 'fc' builtin checks '$EDITOR' as a program to edit history
- entries if 'FCEDIT' is unset, rather than defaulting directly to
- 'ed'. 'fc' uses 'ed' if 'EDITOR' is unset.
+ 1. The ‘fc’ builtin checks ‘$EDITOR’ as a program to edit history
+ entries if ‘FCEDIT’ is unset, rather than defaulting directly to
+ ‘ed’. ‘fc’ uses ‘ed’ if ‘EDITOR’ is unset.
2. A non-interactive shell does not exit if a variable assignment
- preceding the 'command' builtin or another non-special builtin
+ preceding the ‘command’ builtin or another non-special builtin
fails.
- 3. As noted above, Bash requires the 'xpg_echo' option to be enabled
- for the 'echo' builtin to be fully conformant.
+ 3. As noted above, Bash requires the ‘xpg_echo’ option to be enabled
+ for the ‘echo’ builtin to be fully conformant.
Bash can be configured to be POSIX-conformant by default, by
-specifying the '--enable-strict-posix-default' to 'configure' when
+specifying the ‘--enable-strict-posix-default’ to ‘configure’ when
building (*note Optional Features::).
\1f
6.12 Shell Compatibility Mode
=============================
-Bash-4.0 introduced the concept of a "shell compatibility level",
-specified as a set of options to the shopt builtin ('compat31',
-'compat32', 'compat40', 'compat41', and so on). There is only one
+Bash-4.0 introduced the concept of a “shell compatibility level”,
+specified as a set of options to the shopt builtin (‘compat31’,
+‘compat32’, ‘compat40’, ‘compat41’, and so on). There is only one
current compatibility level - each option is mutually exclusive. The
compatibility level is intended to allow users to select behavior from
previous versions that is incompatible with newer versions while they
be a temporary solution.
This section does not mention behavior that is standard for a
-particular version (e.g., setting 'compat32' means that quoting the rhs
+particular version (e.g., setting ‘compat32’ means that quoting the rhs
of the regexp matching operator quotes special regexp characters in the
word, which is default behavior in bash-3.2 and subsequent versions).
- If a user enables, say, 'compat32', it may affect the behavior of
+ If a user enables, say, ‘compat32’, it may affect the behavior of
other compatibility levels up to and including the current compatibility
level. The idea is that each compatibility level controls behavior that
changed in that version of Bash, but that behavior may have been present
in earlier versions. For instance, the change to use locale-based
-comparisons with the '[[' command came in bash-4.1, and earlier versions
-used ASCII-based comparisons, so enabling 'compat32' will enable
+comparisons with the ‘[[’ command came in bash-4.1, and earlier versions
+used ASCII-based comparisons, so enabling ‘compat32’ will enable
ASCII-based comparisons as well. That granularity may not be sufficient
for all uses, and as a result users should employ compatibility levels
carefully. Read the documentation for a particular feature to find out
the current behavior.
- Bash-4.3 introduced a new shell variable: 'BASH_COMPAT'. The value
+ Bash-4.3 introduced a new shell variable: ‘BASH_COMPAT’. The value
assigned to this variable (a decimal version number like 4.2, or an
-integer corresponding to the 'compat'NN option, like 42) determines the
+integer corresponding to the ‘compat’NN option, like 42) determines the
compatibility level.
Starting with bash-4.4, Bash has begun deprecating older
compatibility levels. Eventually, the options will be removed in favor
-of 'BASH_COMPAT'.
+of ‘BASH_COMPAT’.
Bash-5.0 was the final version for which there will be an individual
shopt option for the previous version. Users should control the
-compatibility level with 'BASH_COMPAT'.
+compatibility level with ‘BASH_COMPAT’.
The following table describes the behavior changes controlled by each
-compatibility level setting. The 'compat'NN tag is used as shorthand
+compatibility level setting. The ‘compat’NN tag is used as shorthand
for setting the compatibility level to NN using one of the following
mechanisms. For versions prior to bash-5.0, the compatibility level may
-be set using the corresponding 'compat'NN shopt option. For bash-4.3
-and later versions, the 'BASH_COMPAT' variable is preferred, and it is
+be set using the corresponding ‘compat’NN shopt option. For bash-4.3
+and later versions, the ‘BASH_COMPAT’ variable is preferred, and it is
required for bash-5.1 and later versions.
-'compat31'
- * quoting the rhs of the '[[' command's regexp matching operator
+‘compat31’
+ • quoting the rhs of the ‘[[’ command's regexp matching operator
(=~) has no special effect
-'compat40'
- * the '<' and '>' operators to the '[[' command do not consider
+‘compat40’
+ • the ‘<’ and ‘>’ operators to the ‘[[’ command do not consider
the current locale when comparing strings; they use ASCII
ordering. Bash versions prior to bash-4.1 use ASCII collation
and strcmp(3); bash-4.1 and later use the current locale's
collation sequence and strcoll(3).
-'compat41'
- * in posix mode, 'time' may be followed by options and still be
+‘compat41’
+ • in posix mode, ‘time’ may be followed by options and still be
recognized as a reserved word (this is POSIX interpretation
267)
- * in posix mode, the parser requires that an even number of
+ • in posix mode, the parser requires that an even number of
single quotes occur in the WORD portion of a double-quoted
${...} parameter expansion and treats them specially, so that
characters within the single quotes are considered quoted
(this is POSIX interpretation 221)
-'compat42'
- * the replacement string in double-quoted pattern substitution
+‘compat42’
+ • the replacement string in double-quoted pattern substitution
does not undergo quote removal, as it does in versions after
bash-4.2
- * in posix mode, single quotes are considered special when
+ • in posix mode, single quotes are considered special when
expanding the WORD portion of a double-quoted ${...} parameter
expansion and can be used to quote a closing brace or other
special character (this is part of POSIX interpretation 221);
in later versions, single quotes are not special within
double-quoted word expansions
-'compat43'
- * the shell does not print a warning message if an attempt is
+‘compat43’
+ • the shell does not print a warning message if an attempt is
made to use a quoted compound assignment as an argument to
declare (e.g., declare -a foo='(1 2)'). Later versions warn
that this usage is deprecated
- * word expansion errors are considered non-fatal errors that
+ • word expansion errors are considered non-fatal errors that
cause the current command to fail, even in posix mode (the
default behavior is to make them fatal errors that cause the
shell to exit)
- * when executing a shell function, the loop state
- (while/until/etc.) is not reset, so 'break' or 'continue' in
+ • when executing a shell function, the loop state
+ (while/until/etc.) is not reset, so ‘break’ or ‘continue’ in
that function will break or continue loops in the calling
context. Bash-4.4 and later reset the loop state to prevent
this
-'compat44'
- * the shell sets up the values used by 'BASH_ARGV' and
- 'BASH_ARGC' so they can expand to the shell's positional
+‘compat44’
+ • the shell sets up the values used by ‘BASH_ARGV’ and
+ ‘BASH_ARGC’ so they can expand to the shell's positional
parameters even if extended debugging mode is not enabled
- * a subshell inherits loops from its parent context, so 'break'
- or 'continue' will cause the subshell to exit. Bash-5.0 and
+ • a subshell inherits loops from its parent context, so ‘break’
+ or ‘continue’ will cause the subshell to exit. Bash-5.0 and
later reset the loop state to prevent the exit
- * variable assignments preceding builtins like 'export' and
- 'readonly' that set attributes continue to affect variables
+ • variable assignments preceding builtins like ‘export’ and
+ ‘readonly’ that set attributes continue to affect variables
with the same name in the calling environment even if the
shell is not in posix mode
-'compat50 (set using BASH_COMPAT)'
- * Bash-5.1 changed the way '$RANDOM' is generated to introduce
+‘compat50 (set using BASH_COMPAT)’
+ • Bash-5.1 changed the way ‘$RANDOM’ is generated to introduce
slightly more randomness. If the shell compatibility level is
set to 50 or lower, it reverts to the method from bash-5.0 and
previous versions, so seeding the random number generator by
- assigning a value to 'RANDOM' will produce the same sequence
+ assigning a value to ‘RANDOM’ will produce the same sequence
as in bash-5.0
- * If the command hash table is empty, Bash versions prior to
+ • If the command hash table is empty, Bash versions prior to
bash-5.1 printed an informational message to that effect, even
when producing output that can be reused as input. Bash-5.1
- suppresses that message when the '-l' option is supplied.
+ suppresses that message when the ‘-l’ option is supplied.
-'compat51 (set using BASH_COMPAT)'
- * The 'unset' builtin will unset the array 'a' given an argument
- like 'a[@]'. Bash-5.2 will unset an element with key '@'
+‘compat51 (set using BASH_COMPAT)’
+ • The ‘unset’ builtin will unset the array ‘a’ given an argument
+ like ‘a[@]’. Bash-5.2 will unset an element with key ‘@’
(associative arrays) or remove all the elements without
unsetting the array (indexed arrays)
- * arithmetic commands ( ((...)) ) and the expressions in an
+ • arithmetic commands ( ((...)) ) and the expressions in an
arithmetic for statement can be expanded more than once
- * expressions used as arguments to arithmetic operators in the
- '[[' conditional command can be expanded more than once
- * the expressions in substring parameter brace expansion can be
+ • expressions used as arguments to arithmetic operators in the
+ ‘[[’ conditional command can be expanded more than once
+ • the expressions in substring parameter brace expansion can be
expanded more than once
- * the expressions in the $(( ... )) word expansion can be
+ • the expressions in the $(( ... )) word expansion can be
expanded more than once
- * arithmetic expressions used as indexed array subscripts can be
+ • arithmetic expressions used as indexed array subscripts can be
expanded more than once
- * 'test -v', when given an argument of 'A[@]', where A is an
+ • ‘test -v’, when given an argument of ‘A[@]’, where A is an
existing associative array, will return true if the array has
any set elements. Bash-5.2 will look for and report on a key
- named '@'
- * the ${PARAMETER[:]=VALUE} word expansion will return VALUE,
+ named ‘@’
+ • the ${PARAMETER[:]=VALUE} word expansion will return VALUE,
before any variable-specific transformations have been
performed (e.g., converting to lowercase). Bash-5.2 will
return the final value assigned to the variable.
- * Parsing command substitutions will behave as if extended
+ • Parsing command substitutions will behave as if extended
globbing (*note The Shopt Builtin::) is enabled, so that
parsing a command substitution containing an extglob pattern
(say, as part of a shell function) will not fail. This
driver and Bash.
The shell associates a JOB with each pipeline. It keeps a table of
-currently executing jobs, which may be listed with the 'jobs' command.
+currently executing jobs, which may be listed with the ‘jobs’ command.
When Bash starts a job asynchronously, it prints a line that looks like:
[1] 25647
indicating that this job is job number 1 and that the process ID of the
control, the operating system maintains the notion of a current terminal
process group ID. Members of this process group (processes whose
process group ID is equal to the current terminal process group ID)
-receive keyboard-generated signals such as 'SIGINT'. These processes
+receive keyboard-generated signals such as ‘SIGINT’. These processes
are said to be in the foreground. Background processes are those whose
process group ID differs from the terminal's; such processes are immune
to keyboard-generated signals. Only foreground processes are allowed to
-read from or, if the user so specifies with 'stty tostop', write to the
+read from or, if the user so specifies with ‘stty tostop’, write to the
terminal. Background processes which attempt to read from (write to
-when 'stty tostop' is in effect) the terminal are sent a 'SIGTTIN'
-('SIGTTOU') signal by the kernel's terminal driver, which, unless
+when ‘tostop’ is in effect) the terminal are sent a ‘SIGTTIN’
+(‘SIGTTOU’) signal by the kernel's terminal driver, which, unless
caught, suspends the process.
If the operating system on which Bash is running supports job
-control, Bash contains facilities to use it. Typing the "suspend"
-character (typically '^Z', Control-Z) while a process is running causes
+control, Bash contains facilities to use it. Typing the “suspend”
+character (typically ‘^Z’, Control-Z) while a process is running causes
that process to be stopped and returns control to Bash. Typing the
-"delayed suspend" character (typically '^Y', Control-Y) causes the
+“delayed suspend” character (typically ‘^Y’, Control-Y) causes the
process to be stopped when it attempts to read input from the terminal,
and control to be returned to Bash. The user then manipulates the state
-of this job, using the 'bg' command to continue it in the background,
-the 'fg' command to continue it in the foreground, or the 'kill' command
-to kill it. A '^Z' takes effect immediately, and has the additional
+of this job, using the ‘bg’ command to continue it in the background,
+the ‘fg’ command to continue it in the foreground, or the ‘kill’ command
+to kill it. A ‘^Z’ takes effect immediately, and has the additional
side effect of causing pending output and typeahead to be discarded.
There are a number of ways to refer to a job in the shell. The
-character '%' introduces a job specification ("jobspec").
+character ‘%’ introduces a job specification (“jobspec”).
- Job number 'n' may be referred to as '%n'. The symbols '%%' and '%+'
+ Job number ‘n’ may be referred to as ‘%n’. The symbols ‘%%’ and ‘%+’
refer to the shell's notion of the current job, which is the last job
stopped while it was in the foreground or started in the background. A
-single '%' (with no accompanying job specification) also refers to the
-current job. The previous job may be referenced using '%-'. If there
-is only a single job, '%+' and '%-' can both be used to refer to that
-job. In output pertaining to jobs (e.g., the output of the 'jobs'
-command), the current job is always flagged with a '+', and the previous
-job with a '-'.
+single ‘%’ (with no accompanying job specification) also refers to the
+current job. The previous job may be referenced using ‘%-’. If there
+is only a single job, ‘%+’ and ‘%-’ can both be used to refer to that
+job. In output pertaining to jobs (e.g., the output of the ‘jobs’
+command), the current job is always flagged with a ‘+’, and the previous
+job with a ‘-’.
A job may also be referred to using a prefix of the name used to
start it, or using a substring that appears in its command line. For
-example, '%ce' refers to a stopped job whose command name begins with
-'ce'. Using '%?ce', on the other hand, refers to any job containing the
-string 'ce' in its command line. If the prefix or substring matches
+example, ‘%ce’ refers to a stopped job whose command name begins with
+‘ce’. Using ‘%?ce’, on the other hand, refers to any job containing the
+string ‘ce’ in its command line. If the prefix or substring matches
more than one job, Bash reports an error.
- Simply naming a job can be used to bring it into the foreground: '%1'
-is a synonym for 'fg %1', bringing job 1 from the background into the
-foreground. Similarly, '%1 &' resumes job 1 in the background,
-equivalent to 'bg %1'
+ Simply naming a job can be used to bring it into the foreground: ‘%1’
+is a synonym for ‘fg %1’, bringing job 1 from the background into the
+foreground. Similarly, ‘%1 &’ resumes job 1 in the background,
+equivalent to ‘bg %1’
The shell learns immediately whenever a job changes state. Normally,
Bash waits until it is about to print a prompt before reporting changes
-in a job's status so as to not interrupt any other output. If the '-b'
-option to the 'set' builtin is enabled, Bash reports such changes
-immediately (*note The Set Builtin::). Any trap on 'SIGCHLD' is
+in a job's status so as to not interrupt any other output. If the ‘-b’
+option to the ‘set’ builtin is enabled, Bash reports such changes
+immediately (*note The Set Builtin::). Any trap on ‘SIGCHLD’ is
executed for each child process that exits.
If an attempt to exit Bash is made while jobs are stopped, (or
-running, if the 'checkjobs' option is enabled - see *note The Shopt
-Builtin::), the shell prints a warning message, and if the 'checkjobs'
-option is enabled, lists the jobs and their statuses. The 'jobs'
+running, if the ‘checkjobs’ option is enabled - see *note The Shopt
+Builtin::), the shell prints a warning message, and if the ‘checkjobs’
+option is enabled, lists the jobs and their statuses. The ‘jobs’
command may then be used to inspect their status. If a second attempt
to exit is made without an intervening command, Bash does not print
another warning, and any stopped jobs are terminated.
- When the shell is waiting for a job or process using the 'wait'
-builtin, and job control is enabled, 'wait' will return when the job
-changes state. The '-f' option causes 'wait' to wait until the job or
+ When the shell is waiting for a job or process using the ‘wait’
+builtin, and job control is enabled, ‘wait’ will return when the job
+changes state. The ‘-f’ option causes ‘wait’ to wait until the job or
process terminates before returning.
\1f
7.2 Job Control Builtins
========================
-'bg'
+‘bg’
bg [JOBSPEC ...]
Resume each suspended job JOBSPEC in the background, as if it had
- been started with '&'. If JOBSPEC is not supplied, the current job
+ been started with ‘&’. If JOBSPEC is not supplied, the current job
is used. The return status is zero unless it is run when job
control is not enabled, or, when run with job control enabled, any
JOBSPEC was not found or specifies a job that was started without
job control.
-'fg'
+‘fg’
fg [JOBSPEC]
Resume the job JOBSPEC in the foreground and make it the current
control enabled, JOBSPEC does not specify a valid job or JOBSPEC
specifies a job that was started without job control.
-'jobs'
+‘jobs’
jobs [-lnprs] [JOBSPEC]
jobs -x COMMAND [ARGUMENTS]
The first form lists the active jobs. The options have the
following meanings:
- '-l'
+ ‘-l’
List process IDs in addition to the normal information.
- '-n'
+ ‘-n’
Display information only about jobs that have changed status
since the user was last notified of their status.
- '-p'
+ ‘-p’
List only the process ID of the job's process group leader.
- '-r'
+ ‘-r’
Display only running jobs.
- '-s'
+ ‘-s’
Display only stopped jobs.
If JOBSPEC is given, output is restricted to information about that
job. If JOBSPEC is not supplied, the status of all jobs is listed.
- If the '-x' option is supplied, 'jobs' replaces any JOBSPEC found
+ If the ‘-x’ option is supplied, ‘jobs’ replaces any JOBSPEC found
in COMMAND or ARGUMENTS with the corresponding process group ID,
and executes COMMAND, passing it ARGUMENTs, returning its exit
status.
-'kill'
+‘kill’
kill [-s SIGSPEC] [-n SIGNUM] [-SIGSPEC] JOBSPEC or PID
kill -l|-L [EXIT_STATUS]
Send a signal specified by SIGSPEC or SIGNUM to the process named
by job specification JOBSPEC or process ID PID. SIGSPEC is either
- a case-insensitive signal name such as 'SIGINT' (with or without
- the 'SIG' prefix) or a signal number; SIGNUM is a signal number.
- If SIGSPEC and SIGNUM are not present, 'SIGTERM' is used. The '-l'
+ a case-insensitive signal name such as ‘SIGINT’ (with or without
+ the ‘SIG’ prefix) or a signal number; SIGNUM is a signal number.
+ If SIGSPEC and SIGNUM are not present, ‘SIGTERM’ is used. The ‘-l’
option lists the signal names. If any arguments are supplied when
- '-l' is given, the names of the signals corresponding to the
+ ‘-l’ is given, the names of the signals corresponding to the
arguments are listed, and the return status is zero. EXIT_STATUS
is a number specifying a signal number or the exit status of a
- process terminated by a signal. The '-L' option is equivalent to
- '-l'. The return status is zero if at least one signal was
+ process terminated by a signal. The ‘-L’ option is equivalent to
+ ‘-l’. The return status is zero if at least one signal was
successfully sent, or non-zero if an error occurs or an invalid
option is encountered.
-'wait'
+‘wait’
wait [-fn] [-p VARNAME] [JOBSPEC or PID ...]
Wait until the child process specified by each process ID PID or
job specification JOBSPEC exits and return the exit status of the
last command waited for. If a job spec is given, all processes in
- the job are waited for. If no arguments are given, 'wait' waits
+ the job are waited for. If no arguments are given, ‘wait’ waits
for all running background jobs and the last-executed process
substitution, if its process id is the same as $!, and the return
- status is zero. If the '-n' option is supplied, 'wait' waits for a
+ status is zero. If the ‘-n’ option is supplied, ‘wait’ waits for a
single job from the list of PIDs or JOBSPECs or, if no arguments
are supplied, any job, to complete and returns its exit status. If
none of the supplied arguments is a child of the shell, or if no
arguments are supplied and the shell has no unwaited-for children,
- the exit status is 127. If the '-p' option is supplied, the
+ the exit status is 127. If the ‘-p’ option is supplied, the
process or job identifier of the job for which the exit status is
returned is assigned to the variable VARNAME named by the option
argument. The variable will be unset initially, before any
- assignment. This is useful only when the '-n' option is supplied.
- Supplying the '-f' option, when job control is enabled, forces
- 'wait' to wait for each PID or JOBSPEC to terminate before
+ assignment. This is useful only when the ‘-n’ option is supplied.
+ Supplying the ‘-f’ option, when job control is enabled, forces
+ ‘wait’ to wait for each PID or JOBSPEC to terminate before
returning its status, instead of returning when it changes status.
If neither JOBSPEC nor PID specifies an active child process of the
- shell, the return status is 127. If 'wait' is interrupted by a
+ shell, the return status is 127. If ‘wait’ is interrupted by a
signal, the return status will be greater than 128, as described
above (*note Signals::). Otherwise, the return status is the exit
status of the last process or job waited for.
-'disown'
+‘disown’
disown [-ar] [-h] [JOBSPEC ... | PID ... ]
Without options, remove each JOBSPEC from the table of active jobs.
- If the '-h' option is given, the job is not removed from the table,
- but is marked so that 'SIGHUP' is not sent to the job if the shell
- receives a 'SIGHUP'. If JOBSPEC is not present, and neither the
- '-a' nor the '-r' option is supplied, the current job is used. If
- no JOBSPEC is supplied, the '-a' option means to remove or mark all
- jobs; the '-r' option without a JOBSPEC argument restricts
+ If the ‘-h’ option is given, the job is not removed from the table,
+ but is marked so that ‘SIGHUP’ is not sent to the job if the shell
+ receives a ‘SIGHUP’. If JOBSPEC is not present, and neither the
+ ‘-a’ nor the ‘-r’ option is supplied, the current job is used. If
+ no JOBSPEC is supplied, the ‘-a’ option means to remove or mark all
+ jobs; the ‘-r’ option without a JOBSPEC argument restricts
operation to running jobs.
-'suspend'
+‘suspend’
suspend [-f]
- Suspend the execution of this shell until it receives a 'SIGCONT'
+ Suspend the execution of this shell until it receives a ‘SIGCONT’
signal. A login shell, or a shell without job control enabled,
- cannot be suspended; the '-f' option can be used to override this
+ cannot be suspended; the ‘-f’ option can be used to override this
and force the suspension. The return status is 0 unless the shell
- is a login shell or job control is not enabled and '-f' is not
+ is a login shell or job control is not enabled and ‘-f’ is not
supplied.
- When job control is not active, the 'kill' and 'wait' builtins do not
+ When job control is not active, the ‘kill’ and ‘wait’ builtins do not
accept JOBSPEC arguments. They must be supplied process IDs.
\1f
7.3 Job Control Variables
=========================
-'auto_resume'
+‘auto_resume’
This variable controls how the shell interacts with the user and
job control. If this variable exists then single word simple
commands without redirections are treated as candidates for
there is more than one job beginning with the string typed, then
the most recently accessed job will be selected. The name of a
stopped job, in this context, is the command line used to start it.
- If this variable is set to the value 'exact', the string supplied
+ If this variable is set to the value ‘exact’, the string supplied
must match the name of a stopped job exactly; if set to
- 'substring', the string supplied needs to match a substring of the
- name of a stopped job. The 'substring' value provides
- functionality analogous to the '%?' job ID (*note Job Control
+ ‘substring’, the string supplied needs to match a substring of the
+ name of a stopped job. The ‘substring’ value provides
+ functionality analogous to the ‘%?’ job ID (*note Job Control
Basics::). If set to any other value, the supplied string must be
a prefix of a stopped job's name; this provides functionality
- analogous to the '%' job ID.
+ analogous to the ‘%’ job ID.
\1f
File: bashref.info, Node: Command Line Editing, Next: Using History Interactively, Prev: Job Control, Up: Top
editing interface. Command line editing is provided by the Readline
library, which is used by several different programs, including Bash.
Command line editing is enabled by default when using an interactive
-shell, unless the '--noediting' option is supplied at shell invocation.
-Line editing is also used when using the '-e' option to the 'read'
+shell, unless the ‘--noediting’ option is supplied at shell invocation.
+Line editing is also used when using the ‘-e’ option to the ‘read’
builtin command (*note Bash Builtins::). By default, the line editing
commands are similar to those of Emacs. A vi-style line editing
interface is also available. Line editing can be enabled at any time
-using the '-o emacs' or '-o vi' options to the 'set' builtin command
-(*note The Set Builtin::), or disabled using the '+o emacs' or '+o vi'
-options to 'set'.
+using the ‘-o emacs’ or ‘-o vi’ options to the ‘set’ builtin command
+(*note The Set Builtin::), or disabled using the ‘+o emacs’ or ‘+o vi’
+options to ‘set’.
* Menu:
The following paragraphs describe the notation used to represent
keystrokes.
- The text 'C-k' is read as 'Control-K' and describes the character
+ The text ‘C-k’ is read as 'Control-K' and describes the character
produced when the <k> key is pressed while the Control key is depressed.
- The text 'M-k' is read as 'Meta-K' and describes the character
+ The text ‘M-k’ is read as 'Meta-K' and describes the character
produced when the Meta key (if you have one) is depressed, and the <k>
key is pressed. The Meta key is labeled <ALT> on many keyboards. On
keyboards with two keys labeled <ALT> (usually to either side of the
If you do not have a Meta or <ALT> key, or another key working as a
Meta key, the identical keystroke can be generated by typing <ESC>
-_first_, and then typing <k>. Either process is known as "metafying"
+_first_, and then typing <k>. Either process is known as “metafying”
the <k> key.
- The text 'M-C-k' is read as 'Meta-Control-k' and describes the
-character produced by "metafying" 'C-k'.
+ The text ‘M-C-k’ is read as 'Meta-Control-k' and describes the
+character produced by “metafying” ‘C-k’.
In addition, several keys have their own names. Specifically, <DEL>,
<ESC>, <LFD>, <SPC>, <RET>, and <TAB> all stand for themselves when seen
Sometimes you may mistype a character, and not notice the error until
you have typed several other characters. In that case, you can type
-'C-b' to move the cursor to the left, and then correct your mistake.
-Afterwards, you can move the cursor to the right with 'C-f'.
+‘C-b’ to move the cursor to the left, and then correct your mistake.
+Afterwards, you can move the cursor to the right with ‘C-f’.
When you add text in the middle of a line, you will notice that
characters to the right of the cursor are 'pushed over' to make room for
fill in the blank space created by the removal of the text. A list of
the bare essentials for editing the text of an input line follows.
-'C-b'
+‘C-b’
Move back one character.
-'C-f'
+‘C-f’
Move forward one character.
<DEL> or <Backspace>
Delete the character to the left of the cursor.
-'C-d'
+‘C-d’
Delete the character underneath the cursor.
Printing characters
Insert the character into the line at the cursor.
-'C-_' or 'C-x C-u'
+‘C-_’ or ‘C-x C-u’
Undo the last editing command. You can undo all the way back to an
empty line.
(Depending on your configuration, the <Backspace> key might be set to
delete the character to the left of the cursor and the <DEL> key set to
-delete the character underneath the cursor, like 'C-d', rather than the
+delete the character underneath the cursor, like ‘C-d’, rather than the
character to the left of the cursor.)
\1f
The above table describes the most basic keystrokes that you need in
order to do editing of the input line. For your convenience, many other
-commands have been added in addition to 'C-b', 'C-f', 'C-d', and <DEL>.
+commands have been added in addition to ‘C-b’, ‘C-f’, ‘C-d’, and <DEL>.
Here are some commands for moving more rapidly about the line.
-'C-a'
+‘C-a’
Move to the start of the line.
-'C-e'
+‘C-e’
Move to the end of the line.
-'M-f'
+‘M-f’
Move forward a word, where a word is composed of letters and
digits.
-'M-b'
+‘M-b’
Move backward a word.
-'C-l'
+‘C-l’
Clear the screen, reprinting the current line at the top.
- Notice how 'C-f' moves forward a character, while 'M-f' moves forward
+ Notice how ‘C-f’ moves forward a character, while ‘M-f’ moves forward
a word. It is a loose convention that control keystrokes operate on
characters while meta keystrokes operate on words.
8.2.3 Readline Killing Commands
-------------------------------
-"Killing" text means to delete the text from the line, but to save it
-away for later use, usually by "yanking" (re-inserting) it back into the
+“Killing” text means to delete the text from the line, but to save it
+away for later use, usually by “yanking” (re-inserting) it back into the
line. ('Cut' and 'paste' are more recent jargon for 'kill' and 'yank'.)
If the description for a command says that it 'kills' text, then you
can be sure that you can get the text back in a different (or the same)
place later.
- When you use a kill command, the text is saved in a "kill-ring". Any
+ When you use a kill command, the text is saved in a “kill-ring”. Any
number of consecutive kills save all of the killed text together, so
that when you yank it back, you get it all. The kill ring is not line
specific; the text that you killed on a previously typed line is
Here is the list of commands for killing text.
-'C-k'
+‘C-k’
Kill the text from the current cursor position to the end of the
line.
-'M-d'
+‘M-d’
Kill from the cursor to the end of the current word, or, if between
words, to the end of the next word. Word boundaries are the same
- as those used by 'M-f'.
+ as those used by ‘M-f’.
-'M-<DEL>'
+‘M-<DEL>’
Kill from the cursor to the start of the current word, or, if
between words, to the start of the previous word. Word boundaries
- are the same as those used by 'M-b'.
+ are the same as those used by ‘M-b’.
-'C-w'
+‘C-w’
Kill from the cursor to the previous whitespace. This is different
- than 'M-<DEL>' because the word boundaries differ.
+ than ‘M-<DEL>’ because the word boundaries differ.
- Here is how to "yank" the text back into the line. Yanking means to
+ Here is how to “yank” the text back into the line. Yanking means to
copy the most-recently-killed text from the kill buffer.
-'C-y'
+‘C-y’
Yank the most recently killed text back into the buffer at the
cursor.
-'M-y'
+‘M-y’
Rotate the kill-ring, and yank the new top. You can only do this
- if the prior command is 'C-y' or 'M-y'.
+ if the prior command is ‘C-y’ or ‘M-y’.
\1f
File: bashref.info, Node: Readline Arguments, Next: Searching, Prev: Readline Killing Commands, Up: Readline Interaction
argument that is significant. If you pass a negative argument to a
command which normally acts in a forward direction, that command will
act in a backward direction. For example, to kill text back to the
-start of the line, you might type 'M-- C-k'.
+start of the line, you might type ‘M-- C-k’.
The general way to pass numeric arguments to a command is to type
meta digits before the command. If the first 'digit' typed is a minus
-sign ('-'), then the sign of the argument will be negative. Once you
+sign (‘-’), then the sign of the argument will be negative. Once you
have typed one meta digit to get the argument started, you can type the
remainder of the digits, and then the command. For example, to give the
-'C-d' command an argument of 10, you could type 'M-1 0 C-d', which will
+‘C-d’ command an argument of 10, you could type ‘M-1 0 C-d’, which will
delete the next ten characters on the input line.
\1f
Readline provides commands for searching through the command history
(*note Bash History Facilities::) for lines containing a specified
-string. There are two search modes: "incremental" and
-"non-incremental".
+string. There are two search modes: “incremental” and
+“non-incremental”.
Incremental searches begin before the user has finished typing the
search string. As each character of the search string is typed,
Readline displays the next entry from the history matching the string
typed so far. An incremental search requires only as many characters as
needed to find the desired history entry. To search backward in the
-history for a particular string, type 'C-r'. Typing 'C-s' searches
+history for a particular string, type ‘C-r’. Typing ‘C-s’ searches
forward through the history. The characters present in the value of the
-'isearch-terminators' variable are used to terminate an incremental
+‘isearch-terminators’ variable are used to terminate an incremental
search. If that variable has not been assigned a value, the <ESC> and
-'C-J' characters will terminate an incremental search. 'C-g' will abort
+‘C-J’ characters will terminate an incremental search. ‘C-g’ will abort
an incremental search and restore the original line. When the search is
terminated, the history entry containing the search string becomes the
current line.
- To find other matching entries in the history list, type 'C-r' or
-'C-s' as appropriate. This will search backward or forward in the
+ To find other matching entries in the history list, type ‘C-r’ or
+‘C-s’ as appropriate. This will search backward or forward in the
history for the next entry matching the search string typed so far. Any
other key sequence bound to a Readline command will terminate the search
and execute that command. For instance, a <RET> will terminate the
history list. A movement command will terminate the search, make the
last line found the current line, and begin editing.
- Readline remembers the last incremental search string. If two 'C-r's
+ Readline remembers the last incremental search string. If two ‘C-r’s
are typed without any intervening characters defining a new search
-string, any remembered search string is used.
+string, Readline uses any remembered search string.
Non-incremental searches read the entire search string before
starting to search for matching history lines. The search string may be
Although the Readline library comes with a set of Emacs-like keybindings
installed by default, it is possible to use a different set of
keybindings. Any user can customize programs that use Readline by
-putting commands in an "inputrc" file, conventionally in their home
+putting commands in an “inputrc” file, conventionally in their home
directory. The name of this file is taken from the value of the shell
-variable 'INPUTRC'. If that variable is unset, the default is
-'~/.inputrc'. If that file does not exist or cannot be read, the
-ultimate default is '/etc/inputrc'. The 'bind' builtin command can also
+variable ‘INPUTRC’. If that variable is unset, the default is
+‘~/.inputrc’. If that file does not exist or cannot be read, the
+ultimate default is ‘/etc/inputrc’. The ‘bind’ builtin command can also
be used to set Readline keybindings and variables. *Note Bash
Builtins::.
When a program which uses the Readline library starts up, the init
file is read, and the key bindings are set.
- In addition, the 'C-x C-r' command re-reads this init file, thus
+ In addition, the ‘C-x C-r’ command re-reads this init file, thus
incorporating any changes that you might have made to it.
* Menu:
-------------------------------
There are only a few basic constructs allowed in the Readline init file.
-Blank lines are ignored. Lines beginning with a '#' are comments.
-Lines beginning with a '$' indicate conditional constructs (*note
+Blank lines are ignored. Lines beginning with a ‘#’ are comments.
+Lines beginning with a ‘$’ indicate conditional constructs (*note
Conditional Init Constructs::). Other lines denote variable settings
and key bindings.
Variable Settings
You can modify the run-time behavior of Readline by altering the
- values of variables in Readline using the 'set' command within the
+ values of variables in Readline using the ‘set’ command within the
init file. The syntax is simple:
set VARIABLE VALUE
Here, for example, is how to change from the default Emacs-like key
- binding to use 'vi' line editing commands:
+ binding to use ‘vi’ line editing commands:
set editing-mode vi
on if the value is null or empty, ON (case-insensitive), or 1. Any
other value results in the variable being set to off.
- The 'bind -V' command lists the current Readline variable names and
+ The ‘bind -V’ command lists the current Readline variable names and
values. *Note Bash Builtins::.
A great deal of run-time behavior is changeable with the following
variables.
- 'active-region-start-color'
+ ‘active-region-start-color’
A string variable that controls the text color and background
when displaying the text in the active region (see the
- description of 'enable-active-region' below). This string
+ description of ‘enable-active-region’ below). This string
must not take up any physical character positions on the
display, so it should consist only of terminal escape
sequences. It is output to the terminal before displaying the
default value whenever the terminal type changes. The default
value is the string that puts the terminal in standout mode,
as obtained from the terminal's terminfo description. A
- sample value might be '\e[01;33m'.
+ sample value might be ‘\e[01;33m’.
- 'active-region-end-color'
+ ‘active-region-end-color’
A string variable that "undoes" the effects of
- 'active-region-start-color' and restores "normal" terminal
+ ‘active-region-start-color’ and restores "normal" terminal
display appearance after displaying text in the active region.
This string must not take up any physical character positions
on the display, so it should consist only of terminal escape
default value whenever the terminal type changes. The default
value is the string that restores the terminal from standout
mode, as obtained from the terminal's terminfo description. A
- sample value might be '\e[0m'.
+ sample value might be ‘\e[0m’.
- 'bell-style'
+ ‘bell-style’
Controls what happens when Readline wants to ring the terminal
- bell. If set to 'none', Readline never rings the bell. If
- set to 'visible', Readline uses a visible bell if one is
- available. If set to 'audible' (the default), Readline
+ bell. If set to ‘none’, Readline never rings the bell. If
+ set to ‘visible’, Readline uses a visible bell if one is
+ available. If set to ‘audible’ (the default), Readline
attempts to ring the terminal's bell.
- 'bind-tty-special-chars'
- If set to 'on' (the default), Readline attempts to bind the
+ ‘bind-tty-special-chars’
+ If set to ‘on’ (the default), Readline attempts to bind the
control characters that are treated specially by the kernel's
terminal driver to their Readline equivalents. These override
- the default Readline bindings described here. Type 'stty -a'
+ the default Readline bindings described here. Type ‘stty -a’
at a Bash prompt to see your current terminal settings,
- including the special control characters (usually 'cchars').
+ including the special control characters (usually ‘cchars’).
- 'blink-matching-paren'
- If set to 'on', Readline attempts to briefly move the cursor
+ ‘blink-matching-paren’
+ If set to ‘on’, Readline attempts to briefly move the cursor
to an opening parenthesis when a closing parenthesis is
- inserted. The default is 'off'.
+ inserted. The default is ‘off’.
- 'colored-completion-prefix'
- If set to 'on', when listing completions, Readline displays
+ ‘colored-completion-prefix’
+ If set to ‘on’, when listing completions, Readline displays
the common prefix of the set of possible completions using a
different color. The color definitions are taken from the
- value of the 'LS_COLORS' environment variable. If there is a
- color definition in 'LS_COLORS' for the custom suffix
- 'readline-colored-completion-prefix', Readline uses this color
+ value of the ‘LS_COLORS’ environment variable. If there is a
+ color definition in ‘LS_COLORS’ for the custom suffix
+ ‘readline-colored-completion-prefix’, Readline uses this color
for the common prefix instead of its default. The default is
- 'off'.
+ ‘off’.
- 'colored-stats'
- If set to 'on', Readline displays possible completions using
+ ‘colored-stats’
+ If set to ‘on’, Readline displays possible completions using
different colors to indicate their file type. The color
- definitions are taken from the value of the 'LS_COLORS'
- environment variable. The default is 'off'.
+ definitions are taken from the value of the ‘LS_COLORS’
+ environment variable. The default is ‘off’.
- 'comment-begin'
+ ‘comment-begin’
The string to insert at the beginning of the line when the
- 'insert-comment' command is executed. The default value is
- '"#"'.
+ ‘insert-comment’ command is executed. The default value is
+ ‘"#"’.
- 'completion-display-width'
+ ‘completion-display-width’
The number of screen columns used to display possible matches
when performing completion. The value is ignored if it is
less than 0 or greater than the terminal screen width. A
value of 0 will cause matches to be displayed one per line.
The default value is -1.
- 'completion-ignore-case'
- If set to 'on', Readline performs filename matching and
+ ‘completion-ignore-case’
+ If set to ‘on’, Readline performs filename matching and
completion in a case-insensitive fashion. The default value
- is 'off'.
+ is ‘off’.
- 'completion-map-case'
- If set to 'on', and COMPLETION-IGNORE-CASE is enabled,
- Readline treats hyphens ('-') and underscores ('_') as
+ ‘completion-map-case’
+ If set to ‘on’, and COMPLETION-IGNORE-CASE is enabled,
+ Readline treats hyphens (‘-’) and underscores (‘_’) as
equivalent when performing case-insensitive filename matching
- and completion. The default value is 'off'.
+ and completion. The default value is ‘off’.
- 'completion-prefix-display-length'
+ ‘completion-prefix-display-length’
The length in characters of the common prefix of a list of
possible completions that is displayed without modification.
When set to a value greater than zero, common prefixes longer
than this value are replaced with an ellipsis when displaying
possible completions.
- 'completion-query-items'
+ ‘completion-query-items’
The number of possible completions that determines when the
user is asked whether the list of possibilities should be
displayed. If the number of possible completions is greater
listed. This variable must be set to an integer value greater
than or equal to zero. A zero value means Readline should
never ask; negative values are treated as zero. The default
- limit is '100'.
+ limit is ‘100’.
- 'convert-meta'
- If set to 'on', Readline will convert characters with the
+ ‘convert-meta’
+ If set to ‘on’, Readline will convert characters with the
eighth bit set to an ASCII key sequence by stripping the
eighth bit and prefixing an <ESC> character, converting them
- to a meta-prefixed key sequence. The default value is 'on',
- but will be set to 'off' if the locale is one that contains
+ to a meta-prefixed key sequence. The default value is ‘on’,
+ but will be set to ‘off’ if the locale is one that contains
eight-bit characters. This variable is dependent on the
- 'LC_CTYPE' locale category, and may change if the locale is
+ ‘LC_CTYPE’ locale category, and may change if the locale is
changed.
- 'disable-completion'
- If set to 'On', Readline will inhibit word completion.
+ ‘disable-completion’
+ If set to ‘On’, Readline will inhibit word completion.
Completion characters will be inserted into the line as if
- they had been mapped to 'self-insert'. The default is 'off'.
+ they had been mapped to ‘self-insert’. The default is ‘off’.
- 'echo-control-characters'
- When set to 'on', on operating systems that indicate they
+ ‘echo-control-characters’
+ When set to ‘on’, on operating systems that indicate they
support it, Readline echoes a character corresponding to a
- signal generated from the keyboard. The default is 'on'.
+ signal generated from the keyboard. The default is ‘on’.
- 'editing-mode'
- The 'editing-mode' variable controls which default set of key
+ ‘editing-mode’
+ The ‘editing-mode’ variable controls which default set of key
bindings is used. By default, Readline starts up in Emacs
editing mode, where the keystrokes are most similar to Emacs.
- This variable can be set to either 'emacs' or 'vi'.
+ This variable can be set to either ‘emacs’ or ‘vi’.
- 'emacs-mode-string'
+ ‘emacs-mode-string’
If the SHOW-MODE-IN-PROMPT variable is enabled, this string is
displayed immediately before the last line of the primary
prompt when emacs editing mode is active. The value is
expanded like a key binding, so the standard set of meta- and
control prefixes and backslash escape sequences is available.
- Use the '\1' and '\2' escapes to begin and end sequences of
+ Use the ‘\1’ and ‘\2’ escapes to begin and end sequences of
non-printing characters, which can be used to embed a terminal
- control sequence into the mode string. The default is '@'.
+ control sequence into the mode string. The default is ‘@’.
- 'enable-active-region'
- The "point" is the current cursor position, and "mark" refers
+ ‘enable-active-region’
+ The “point” is the current cursor position, and “mark” refers
to a saved cursor position (*note Commands For Moving::). The
text between the point and mark is referred to as the
- "region". When this variable is set to 'On', Readline allows
- certain commands to designate the region as "active". When
+ “region”. When this variable is set to ‘On’, Readline allows
+ certain commands to designate the region as “active”. When
the region is active, Readline highlights the text in the
- region using the value of the 'active-region-start-color',
+ region using the value of the ‘active-region-start-color’,
which defaults to the string that enables the terminal's
standout mode. The active region shows the text inserted by
bracketed-paste and any matching text found by incremental and
- non-incremental history searches. The default is 'On'.
+ non-incremental history searches. The default is ‘On’.
- 'enable-bracketed-paste'
- When set to 'On', Readline configures the terminal to insert
+ ‘enable-bracketed-paste’
+ When set to ‘On’, Readline configures the terminal to insert
each paste into the editing buffer as a single string of
characters, instead of treating each character as if it had
been read from the keyboard. This is called putting the
- terminal into "bracketed paste mode"; it prevents Readline
+ terminal into “bracketed paste mode”; it prevents Readline
from executing any editing commands bound to key sequences
- appearing in the pasted text. The default is 'On'.
+ appearing in the pasted text. The default is ‘On’.
- 'enable-keypad'
- When set to 'on', Readline will try to enable the application
+ ‘enable-keypad’
+ When set to ‘on’, Readline will try to enable the application
keypad when it is called. Some systems need this to enable
- the arrow keys. The default is 'off'.
+ the arrow keys. The default is ‘off’.
- 'enable-meta-key'
- When set to 'on', Readline will try to enable any meta
+ ‘enable-meta-key’
+ When set to ‘on’, Readline will try to enable any meta
modifier key the terminal claims to support when it is called.
On many terminals, the meta key is used to send eight-bit
- characters. The default is 'on'.
+ characters. The default is ‘on’.
- 'expand-tilde'
- If set to 'on', tilde expansion is performed when Readline
- attempts word completion. The default is 'off'.
+ ‘expand-tilde’
+ If set to ‘on’, tilde expansion is performed when Readline
+ attempts word completion. The default is ‘off’.
- 'history-preserve-point'
- If set to 'on', the history code attempts to place the point
+ ‘history-preserve-point’
+ If set to ‘on’, the history code attempts to place the point
(the current cursor position) at the same location on each
- history line retrieved with 'previous-history' or
- 'next-history'. The default is 'off'.
+ history line retrieved with ‘previous-history’ or
+ ‘next-history’. The default is ‘off’.
- 'history-size'
+ ‘history-size’
Set the maximum number of history entries saved in the history
list. If set to zero, any existing history entries are
deleted and no new entries are saved. If set to a value less
attempt is made to set HISTORY-SIZE to a non-numeric value,
the maximum number of history entries will be set to 500.
- 'horizontal-scroll-mode'
- This variable can be set to either 'on' or 'off'. Setting it
- to 'on' means that the text of the lines being edited will
+ ‘horizontal-scroll-mode’
+ This variable can be set to either ‘on’ or ‘off’. Setting it
+ to ‘on’ means that the text of the lines being edited will
scroll horizontally on a single screen line when they are
longer than the width of the screen, instead of wrapping onto
- a new screen line. This variable is automatically set to 'on'
+ a new screen line. This variable is automatically set to ‘on’
for terminals of height 1. By default, this variable is set
- to 'off'.
+ to ‘off’.
- 'input-meta'
- If set to 'on', Readline will enable eight-bit input (it will
+ ‘input-meta’
+ If set to ‘on’, Readline will enable eight-bit input (it will
not clear the eighth bit in the characters it reads),
regardless of what the terminal claims it can support. The
- default value is 'off', but Readline will set it to 'on' if
+ default value is ‘off’, but Readline will set it to ‘on’ if
the locale contains eight-bit characters. The name
- 'meta-flag' is a synonym for this variable. This variable is
- dependent on the 'LC_CTYPE' locale category, and may change if
+ ‘meta-flag’ is a synonym for this variable. This variable is
+ dependent on the ‘LC_CTYPE’ locale category, and may change if
the locale is changed.
- 'isearch-terminators'
+ ‘isearch-terminators’
The string of characters that should terminate an incremental
search without subsequently executing the character as a
command (*note Searching::). If this variable has not been
- given a value, the characters <ESC> and 'C-J' will terminate
+ given a value, the characters <ESC> and ‘C-J’ will terminate
an incremental search.
- 'keymap'
+ ‘keymap’
Sets Readline's idea of the current keymap for key binding
- commands. Built-in 'keymap' names are 'emacs',
- 'emacs-standard', 'emacs-meta', 'emacs-ctlx', 'vi', 'vi-move',
- 'vi-command', and 'vi-insert'. 'vi' is equivalent to
- 'vi-command' ('vi-move' is also a synonym); 'emacs' is
- equivalent to 'emacs-standard'. Applications may add
- additional names. The default value is 'emacs'. The value of
- the 'editing-mode' variable also affects the default keymap.
-
- 'keyseq-timeout'
+ commands. Built-in ‘keymap’ names are ‘emacs’,
+ ‘emacs-standard’, ‘emacs-meta’, ‘emacs-ctlx’, ‘vi’, ‘vi-move’,
+ ‘vi-command’, and ‘vi-insert’. ‘vi’ is equivalent to
+ ‘vi-command’ (‘vi-move’ is also a synonym); ‘emacs’ is
+ equivalent to ‘emacs-standard’. Applications may add
+ additional names. The default value is ‘emacs’. The value of
+ the ‘editing-mode’ variable also affects the default keymap.
+
+ ‘keyseq-timeout’
Specifies the duration Readline will wait for a character when
reading an ambiguous key sequence (one that can form a
complete key sequence using the input read so far, or can take
input is received within the timeout, Readline will use the
shorter but complete key sequence. Readline uses this value
to determine whether or not input is available on the current
- input source ('rl_instream' by default). The value is
+ input source (‘rl_instream’ by default). The value is
specified in milliseconds, so a value of 1000 means that
Readline will wait one second for additional input. If this
variable is set to a value less than or equal to zero, or to a
non-numeric value, Readline will wait until another key is
pressed to decide which key sequence to complete. The default
- value is '500'.
+ value is ‘500’.
- 'mark-directories'
- If set to 'on', completed directory names have a slash
- appended. The default is 'on'.
+ ‘mark-directories’
+ If set to ‘on’, completed directory names have a slash
+ appended. The default is ‘on’.
- 'mark-modified-lines'
- This variable, when set to 'on', causes Readline to display an
- asterisk ('*') at the start of history lines which have been
- modified. This variable is 'off' by default.
+ ‘mark-modified-lines’
+ This variable, when set to ‘on’, causes Readline to display an
+ asterisk (‘*’) at the start of history lines which have been
+ modified. This variable is ‘off’ by default.
- 'mark-symlinked-directories'
- If set to 'on', completed names which are symbolic links to
+ ‘mark-symlinked-directories’
+ If set to ‘on’, completed names which are symbolic links to
directories have a slash appended (subject to the value of
- 'mark-directories'). The default is 'off'.
+ ‘mark-directories’). The default is ‘off’.
- 'match-hidden-files'
- This variable, when set to 'on', causes Readline to match
- files whose names begin with a '.' (hidden files) when
- performing filename completion. If set to 'off', the leading
- '.' must be supplied by the user in the filename to be
- completed. This variable is 'on' by default.
+ ‘match-hidden-files’
+ This variable, when set to ‘on’, forces Readline to match
+ files whose names begin with a ‘.’ (hidden files) when
+ performing filename completion. If set to ‘off’, the user
+ must include the leading ‘.’ in the filename to be completed.
+ This variable is ‘on’ by default.
- 'menu-complete-display-prefix'
- If set to 'on', menu completion displays the common prefix of
+ ‘menu-complete-display-prefix’
+ If set to ‘on’, menu completion displays the common prefix of
the list of possible completions (which may be empty) before
- cycling through the list. The default is 'off'.
+ cycling through the list. The default is ‘off’.
- 'output-meta'
- If set to 'on', Readline will display characters with the
+ ‘output-meta’
+ If set to ‘on’, Readline will display characters with the
eighth bit set directly rather than as a meta-prefixed escape
- sequence. The default is 'off', but Readline will set it to
- 'on' if the locale contains eight-bit characters. This
- variable is dependent on the 'LC_CTYPE' locale category, and
+ sequence. The default is ‘off’, but Readline will set it to
+ ‘on’ if the locale contains eight-bit characters. This
+ variable is dependent on the ‘LC_CTYPE’ locale category, and
may change if the locale is changed.
- 'page-completions'
- If set to 'on', Readline uses an internal 'more'-like pager to
+ ‘page-completions’
+ If set to ‘on’, Readline uses an internal ‘more’-like pager to
display a screenful of possible completions at a time. This
- variable is 'on' by default.
+ variable is ‘on’ by default.
- 'print-completions-horizontally'
- If set to 'on', Readline will display completions with matches
+ ‘print-completions-horizontally’
+ If set to ‘on’, Readline will display completions with matches
sorted horizontally in alphabetical order, rather than down
- the screen. The default is 'off'.
+ the screen. The default is ‘off’.
- 'revert-all-at-newline'
- If set to 'on', Readline will undo all changes to history
- lines before returning when 'accept-line' is executed. By
+ ‘revert-all-at-newline’
+ If set to ‘on’, Readline will undo all changes to history
+ lines before returning when ‘accept-line’ is executed. By
default, history lines may be modified and retain individual
- undo lists across calls to 'readline()'. The default is
- 'off'.
+ undo lists across calls to ‘readline()’. The default is
+ ‘off’.
- 'search-ignore-case'
- If set to 'on', Readline performs incremental and
+ ‘search-ignore-case’
+ If set to ‘on’, Readline performs incremental and
non-incremental history list searches in a case-insensitive
- fashion. The default value is 'off'.
+ fashion. The default value is ‘off’.
- 'show-all-if-ambiguous'
+ ‘show-all-if-ambiguous’
This alters the default behavior of the completion functions.
- If set to 'on', words which have more than one possible
+ If set to ‘on’, words which have more than one possible
completion cause the matches to be listed immediately instead
- of ringing the bell. The default value is 'off'.
+ of ringing the bell. The default value is ‘off’.
- 'show-all-if-unmodified'
+ ‘show-all-if-unmodified’
This alters the default behavior of the completion functions
in a fashion similar to SHOW-ALL-IF-AMBIGUOUS. If set to
- 'on', words which have more than one possible completion
+ ‘on’, words which have more than one possible completion
without any possible partial completion (the possible
completions don't share a common prefix) cause the matches to
be listed immediately instead of ringing the bell. The
- default value is 'off'.
+ default value is ‘off’.
- 'show-mode-in-prompt'
- If set to 'on', add a string to the beginning of the prompt
+ ‘show-mode-in-prompt’
+ If set to ‘on’, add a string to the beginning of the prompt
indicating the editing mode: emacs, vi command, or vi
insertion. The mode strings are user-settable (e.g.,
- EMACS-MODE-STRING). The default value is 'off'.
+ EMACS-MODE-STRING). The default value is ‘off’.
- 'skip-completed-text'
- If set to 'on', this alters the default completion behavior
+ ‘skip-completed-text’
+ If set to ‘on’, this alters the default completion behavior
when inserting a single match into the line. It's only active
when performing completion in the middle of a word. If
enabled, Readline does not insert characters from the
completion that match characters after point in the word being
completed, so portions of the word following the cursor are
not duplicated. For instance, if this is enabled, attempting
- completion when the cursor is after the 'e' in 'Makefile' will
- result in 'Makefile' rather than 'Makefilefile', assuming
+ completion when the cursor is after the ‘e’ in ‘Makefile’ will
+ result in ‘Makefile’ rather than ‘Makefilefile’, assuming
there is a single possible completion. The default value is
- 'off'.
+ ‘off’.
- 'vi-cmd-mode-string'
+ ‘vi-cmd-mode-string’
If the SHOW-MODE-IN-PROMPT variable is enabled, this string is
displayed immediately before the last line of the primary
prompt when vi editing mode is active and in command mode.
The value is expanded like a key binding, so the standard set
of meta- and control prefixes and backslash escape sequences
- is available. Use the '\1' and '\2' escapes to begin and end
+ is available. Use the ‘\1’ and ‘\2’ escapes to begin and end
sequences of non-printing characters, which can be used to
embed a terminal control sequence into the mode string. The
- default is '(cmd)'.
+ default is ‘(cmd)’.
- 'vi-ins-mode-string'
+ ‘vi-ins-mode-string’
If the SHOW-MODE-IN-PROMPT variable is enabled, this string is
displayed immediately before the last line of the primary
prompt when vi editing mode is active and in insertion mode.
The value is expanded like a key binding, so the standard set
of meta- and control prefixes and backslash escape sequences
- is available. Use the '\1' and '\2' escapes to begin and end
+ is available. Use the ‘\1’ and ‘\2’ escapes to begin and end
sequences of non-printing characters, which can be used to
embed a terminal control sequence into the mode string. The
- default is '(ins)'.
+ default is ‘(ins)’.
- 'visible-stats'
- If set to 'on', a character denoting a file's type is appended
+ ‘visible-stats’
+ If set to ‘on’, a character denoting a file's type is appended
to the filename when listing possible completions. The
- default is 'off'.
+ default is ‘off’.
Key Bindings
The syntax for controlling key bindings in the init file is simple.
In addition to command names, Readline allows keys to be bound to a
string that is inserted when the key is pressed (a MACRO).
- The 'bind -p' command displays Readline function names and bindings
+ The ‘bind -p’ command displays Readline function names and bindings
in a format that can be put directly into an initialization file.
*Note Bash Builtins::.
Meta-Rubout: backward-kill-word
Control-o: "> output"
- In the example above, 'C-u' is bound to the function
- 'universal-argument', 'M-DEL' is bound to the function
- 'backward-kill-word', and 'C-o' is bound to run the macro
+ In the example above, ‘C-u’ is bound to the function
+ ‘universal-argument’, ‘M-DEL’ is bound to the function
+ ‘backward-kill-word’, and ‘C-o’ is bound to run the macro
expressed on the right hand side (that is, to insert the text
- '> output' into the line).
+ ‘> output’ into the line).
A number of symbolic character names are recognized while
processing this key binding syntax: DEL, ESC, ESCAPE, LFD,
"\C-x\C-r": re-read-init-file
"\e[11~": "Function Key 1"
- In the above example, 'C-u' is again bound to the function
- 'universal-argument' (just as it was in the first example),
- ''C-x' 'C-r'' is bound to the function 're-read-init-file',
- and '<ESC> <[> <1> <1> <~>' is bound to insert the text
- 'Function Key 1'.
+ In the above example, ‘C-u’ is again bound to the function
+ ‘universal-argument’ (just as it was in the first example),
+ ‘‘C-x’ ‘C-r’’ is bound to the function ‘re-read-init-file’,
+ and ‘<ESC> <[> <1> <1> <~>’ is bound to insert the text
+ ‘Function Key 1’.
The following GNU Emacs style escape sequences are available when
specifying key sequences:
- '\C-'
+ ‘\C-’
control prefix
- '\M-'
+ ‘\M-’
meta prefix
- '\e'
+ ‘\e’
an escape character
- '\\'
+ ‘\\’
backslash
- '\"'
+ ‘\"’
<">, a double quotation mark
- '\''
+ ‘\'’
<'>, a single quote or apostrophe
In addition to the GNU Emacs style escape sequences, a second set
of backslash escapes is available:
- '\a'
+ ‘\a’
alert (bell)
- '\b'
+ ‘\b’
backspace
- '\d'
+ ‘\d’
delete
- '\f'
+ ‘\f’
form feed
- '\n'
+ ‘\n’
newline
- '\r'
+ ‘\r’
carriage return
- '\t'
+ ‘\t’
horizontal tab
- '\v'
+ ‘\v’
vertical tab
- '\NNN'
+ ‘\NNN’
the eight-bit character whose value is the octal value NNN
(one to three digits)
- '\xHH'
+ ‘\xHH’
the eight-bit character whose value is the hexadecimal value
HH (one or two hex digits)
used to indicate a macro definition. Unquoted text is assumed to
be a function name. In the macro body, the backslash escapes
described above are expanded. Backslash will quote any other
- character in the macro text, including '"' and '''. For example,
- the following binding will make ''C-x' \' insert a single '\' into
+ character in the macro text, including ‘"’ and ‘'’. For example,
+ the following binding will make ‘‘C-x’ \’ insert a single ‘\’ into
the line:
"\C-x\\": "\\"
variable settings to be performed as the result of tests. There are
four parser directives used.
-'$if'
- The '$if' construct allows bindings to be made based on the editing
+‘$if’
+ The ‘$if’ construct allows bindings to be made based on the editing
mode, the terminal being used, or the application using Readline.
The text of the test, after any comparison operator, extends to the
end of the line; unless otherwise noted, no characters are required
to isolate it.
- 'mode'
- The 'mode=' form of the '$if' directive is used to test
- whether Readline is in 'emacs' or 'vi' mode. This may be used
- in conjunction with the 'set keymap' command, for instance, to
- set bindings in the 'emacs-standard' and 'emacs-ctlx' keymaps
- only if Readline is starting out in 'emacs' mode.
+ ‘mode’
+ The ‘mode=’ form of the ‘$if’ directive is used to test
+ whether Readline is in ‘emacs’ or ‘vi’ mode. This may be used
+ in conjunction with the ‘set keymap’ command, for instance, to
+ set bindings in the ‘emacs-standard’ and ‘emacs-ctlx’ keymaps
+ only if Readline is starting out in ‘emacs’ mode.
- 'term'
- The 'term=' form may be used to include terminal-specific key
+ ‘term’
+ The ‘term=’ form may be used to include terminal-specific key
bindings, perhaps to bind the key sequences output by the
terminal's function keys. The word on the right side of the
- '=' is tested against both the full name of the terminal and
- the portion of the terminal name before the first '-'. This
- allows 'sun' to match both 'sun' and 'sun-cmd', for instance.
+ ‘=’ is tested against both the full name of the terminal and
+ the portion of the terminal name before the first ‘-’. This
+ allows ‘sun’ to match both ‘sun’ and ‘sun-cmd’, for instance.
- 'version'
- The 'version' test may be used to perform comparisons against
- specific Readline versions. The 'version' expands to the
+ ‘version’
+ The ‘version’ test may be used to perform comparisons against
+ specific Readline versions. The ‘version’ expands to the
current Readline version. The set of comparison operators
- includes '=' (and '=='), '!=', '<=', '>=', '<', and '>'. The
+ includes ‘=’ (and ‘==’), ‘!=’, ‘<=’, ‘>=’, ‘<’, and ‘>’. The
version number supplied on the right side of the operator
consists of a major version number, an optional decimal point,
- and an optional minor version (e.g., '7.1'). If the minor
- version is omitted, it is assumed to be '0'. The operator may
- be separated from the string 'version' and from the version
+ and an optional minor version (e.g., ‘7.1’). If the minor
+ version is omitted, it is assumed to be ‘0’. The operator may
+ be separated from the string ‘version’ and from the version
number argument by whitespace. The following example sets a
variable if the Readline version being used is 7.0 or newer:
$if version >= 7.0
set show-mode-in-prompt on
$endif
- 'application'
+ ‘application’
The APPLICATION construct is used to include
application-specific settings. Each program using the
Readline library sets the APPLICATION NAME, and you can test
"\C-xq": "\eb\"\ef\""
$endif
- 'variable'
+ ‘variable’
The VARIABLE construct provides simple equality tests for
Readline variables and values. The permitted comparison
- operators are '=', '==', and '!='. The variable name must be
+ operators are ‘=’, ‘==’, and ‘!=’. The variable name must be
separated from the comparison operator by whitespace; the
operator may be separated from the value on the right hand
side by whitespace. Both string and boolean variables may be
tested. Boolean variables must be tested against the values
ON and OFF. The following example is equivalent to the
- 'mode=emacs' test described above:
+ ‘mode=emacs’ test described above:
$if editing-mode == emacs
set show-mode-in-prompt on
$endif
-'$endif'
- This command, as seen in the previous example, terminates an '$if'
+‘$endif’
+ This command, as seen in the previous example, terminates an ‘$if’
command.
-'$else'
- Commands in this branch of the '$if' directive are executed if the
+‘$else’
+ Commands in this branch of the ‘$if’ directive are executed if the
test fails.
-'$include'
+‘$include’
This directive takes a single filename as an argument and reads
commands and bindings from that file. For example, the following
- directive reads from '/etc/inputrc':
+ directive reads from ‘/etc/inputrc’:
$include /etc/inputrc
\1f
* Miscellaneous Commands:: Other miscellaneous commands.
This section describes Readline commands that may be bound to key
-sequences. You can list your key bindings by executing 'bind -P' or,
-for a more terse format, suitable for an INPUTRC file, 'bind -p'.
+sequences. You can list your key bindings by executing ‘bind -P’ or,
+for a more terse format, suitable for an INPUTRC file, ‘bind -p’.
(*Note Bash Builtins::.) Command names without an accompanying key
sequence are unbound by default.
- In the following descriptions, "point" refers to the current cursor
-position, and "mark" refers to a cursor position saved by the 'set-mark'
+ In the following descriptions, “point” refers to the current cursor
+position, and “mark” refers to a cursor position saved by the ‘set-mark’
command. The text between the point and mark is referred to as the
-"region".
+“region”.
\1f
File: bashref.info, Node: Commands For Moving, Next: Commands For History, Up: Bindable Readline Commands
8.4.1 Commands For Moving
-------------------------
-'beginning-of-line (C-a)'
+‘beginning-of-line (C-a)’
Move to the start of the current line.
-'end-of-line (C-e)'
+‘end-of-line (C-e)’
Move to the end of the line.
-'forward-char (C-f)'
+‘forward-char (C-f)’
Move forward a character.
-'backward-char (C-b)'
+‘backward-char (C-b)’
Move back a character.
-'forward-word (M-f)'
+‘forward-word (M-f)’
Move forward to the end of the next word. Words are composed of
letters and digits.
-'backward-word (M-b)'
+‘backward-word (M-b)’
Move back to the start of the current or previous word. Words are
composed of letters and digits.
-'shell-forward-word (M-C-f)'
+‘shell-forward-word (M-C-f)’
Move forward to the end of the next word. Words are delimited by
non-quoted shell metacharacters.
-'shell-backward-word (M-C-b)'
+‘shell-backward-word (M-C-b)’
Move back to the start of the current or previous word. Words are
delimited by non-quoted shell metacharacters.
-'previous-screen-line ()'
+‘previous-screen-line ()’
Attempt to move point to the same physical screen column on the
previous physical screen line. This will not have the desired
effect if the current Readline line does not take up more than one
physical line or if point is not greater than the length of the
prompt plus the screen width.
-'next-screen-line ()'
+‘next-screen-line ()’
Attempt to move point to the same physical screen column on the
next physical screen line. This will not have the desired effect
if the current Readline line does not take up more than one
physical line or if the length of the current Readline line is not
greater than the length of the prompt plus the screen width.
-'clear-display (M-C-l)'
+‘clear-display (M-C-l)’
Clear the screen and, if possible, the terminal's scrollback
buffer, then redraw the current line, leaving the current line at
the top of the screen.
-'clear-screen (C-l)'
+‘clear-screen (C-l)’
Clear the screen, then redraw the current line, leaving the current
line at the top of the screen.
-'redraw-current-line ()'
+‘redraw-current-line ()’
Refresh the current line. By default, this is unbound.
\1f
8.4.2 Commands For Manipulating The History
-------------------------------------------
-'accept-line (Newline or Return)'
+‘accept-line (Newline or Return)’
Accept the line regardless of where the cursor is. If this line is
non-empty, add it to the history list according to the setting of
- the 'HISTCONTROL' and 'HISTIGNORE' variables. If this line is a
+ the ‘HISTCONTROL’ and ‘HISTIGNORE’ variables. If this line is a
modified history line, then restore the history line to its
original state.
-'previous-history (C-p)'
+‘previous-history (C-p)’
Move 'back' through the history list, fetching the previous
command.
-'next-history (C-n)'
+‘next-history (C-n)’
Move 'forward' through the history list, fetching the next command.
-'beginning-of-history (M-<)'
+‘beginning-of-history (M-<)’
Move to the first line in the history.
-'end-of-history (M->)'
+‘end-of-history (M->)’
Move to the end of the input history, i.e., the line currently
being entered.
-'reverse-search-history (C-r)'
+‘reverse-search-history (C-r)’
Search backward starting at the current line and moving 'up'
through the history as necessary. This is an incremental search.
This command sets the region to the matched text and activates the
mark.
-'forward-search-history (C-s)'
+‘forward-search-history (C-s)’
Search forward starting at the current line and moving 'down'
through the history as necessary. This is an incremental search.
This command sets the region to the matched text and activates the
mark.
-'non-incremental-reverse-search-history (M-p)'
+‘non-incremental-reverse-search-history (M-p)’
Search backward starting at the current line and moving 'up'
through the history as necessary using a non-incremental search for
a string supplied by the user. The search string may match
anywhere in a history line.
-'non-incremental-forward-search-history (M-n)'
+‘non-incremental-forward-search-history (M-n)’
Search forward starting at the current line and moving 'down'
through the history as necessary using a non-incremental search for
a string supplied by the user. The search string may match
anywhere in a history line.
-'history-search-forward ()'
+‘history-search-forward ()’
Search forward through the history for the string of characters
between the start of the current line and the point. The search
string must match at the beginning of a history line. This is a
non-incremental search. By default, this command is unbound.
-'history-search-backward ()'
+‘history-search-backward ()’
Search backward through the history for the string of characters
between the start of the current line and the point. The search
string must match at the beginning of a history line. This is a
non-incremental search. By default, this command is unbound.
-'history-substring-search-forward ()'
+‘history-substring-search-forward ()’
Search forward through the history for the string of characters
between the start of the current line and the point. The search
string may match anywhere in a history line. This is a
non-incremental search. By default, this command is unbound.
-'history-substring-search-backward ()'
+‘history-substring-search-backward ()’
Search backward through the history for the string of characters
between the start of the current line and the point. The search
string may match anywhere in a history line. This is a
non-incremental search. By default, this command is unbound.
-'yank-nth-arg (M-C-y)'
+‘yank-nth-arg (M-C-y)’
Insert the first argument to the previous command (usually the
second word on the previous line) at point. With an argument N,
insert the Nth word from the previous command (the words in the
previous command begin with word 0). A negative argument inserts
the Nth word from the end of the previous command. Once the
- argument N is computed, the argument is extracted as if the '!N'
+ argument N is computed, the argument is extracted as if the ‘!N’
history expansion had been specified.
-'yank-last-arg (M-. or M-_)'
+‘yank-last-arg (M-. or M-_)’
Insert last argument to the previous command (the last word of the
previous history entry). With a numeric argument, behave exactly
- like 'yank-nth-arg'. Successive calls to 'yank-last-arg' move back
+ like ‘yank-nth-arg’. Successive calls to ‘yank-last-arg’ move back
through the history list, inserting the last word (or the word
specified by the argument to the first call) of each line in turn.
Any numeric argument supplied to these successive calls determines
the direction to move through the history. A negative argument
switches the direction through the history (back or forward). The
history expansion facilities are used to extract the last argument,
- as if the '!$' history expansion had been specified.
+ as if the ‘!$’ history expansion had been specified.
-'operate-and-get-next (C-o)'
+‘operate-and-get-next (C-o)’
Accept the current line for return to the calling application as if
a newline had been entered, and fetch the next line relative to the
current line from the history for editing. A numeric argument, if
supplied, specifies the history entry to use instead of the current
line.
-'fetch-history ()'
+‘fetch-history ()’
With a numeric argument, fetch that entry from the history list and
make it the current line. Without an argument, move back to the
first entry in the history list.
8.4.3 Commands For Changing Text
--------------------------------
-'end-of-file (usually C-d)'
+‘end-of-file (usually C-d)’
The character indicating end-of-file as set, for example, by
- 'stty'. If this character is read when there are no characters on
+ ‘stty’. If this character is read when there are no characters on
the line, and point is at the beginning of the line, Readline
interprets it as the end of input and returns EOF.
-'delete-char (C-d)'
+‘delete-char (C-d)’
Delete the character at point. If this function is bound to the
- same character as the tty EOF character, as 'C-d' commonly is, see
+ same character as the tty EOF character, as ‘C-d’ commonly is, see
above for the effects.
-'backward-delete-char (Rubout)'
+‘backward-delete-char (Rubout)’
Delete the character behind the cursor. A numeric argument means
to kill the characters instead of deleting them.
-'forward-backward-delete-char ()'
+‘forward-backward-delete-char ()’
Delete the character under the cursor, unless the cursor is at the
end of the line, in which case the character behind the cursor is
deleted. By default, this is not bound to a key.
-'quoted-insert (C-q or C-v)'
+‘quoted-insert (C-q or C-v)’
Add the next character typed to the line verbatim. This is how to
- insert key sequences like 'C-q', for example.
+ insert key sequences like ‘C-q’, for example.
-'self-insert (a, b, A, 1, !, ...)'
+‘self-insert (a, b, A, 1, !, ...)’
Insert yourself.
-'bracketed-paste-begin ()'
+‘bracketed-paste-begin ()’
This function is intended to be bound to the "bracketed paste"
escape sequence sent by some terminals, and such a binding is
assigned by default. It allows Readline to insert the pasted text
as a single unit without treating each character as if it had been
read from the keyboard. The characters are inserted as if each one
- was bound to 'self-insert' instead of executing any editing
+ was bound to ‘self-insert’ instead of executing any editing
commands.
Bracketed paste sets the region (the characters between point and
mark_: when the mark is active, Readline redisplay uses the
terminal's standout mode to denote the region.
-'transpose-chars (C-t)'
+‘transpose-chars (C-t)’
Drag the character before the cursor forward over the character at
the cursor, moving the cursor forward as well. If the insertion
point is at the end of the line, then this transposes the last two
characters of the line. Negative arguments have no effect.
-'transpose-words (M-t)'
+‘transpose-words (M-t)’
Drag the word before point past the word after point, moving point
past that word as well. If the insertion point is at the end of
the line, this transposes the last two words on the line.
-'shell-transpose-words (M-C-t)'
+‘shell-transpose-words (M-C-t)’
Drag the word before point past the word after point, moving point
past that word as well. If the insertion point is at the end of
the line, this transposes the last two words on the line. Word
- boundaries are the same as 'shell-forward-word' and
- 'shell-backward-word'.
+ boundaries are the same as ‘shell-forward-word’ and
+ ‘shell-backward-word’.
-'upcase-word (M-u)'
+‘upcase-word (M-u)’
Uppercase the current (or following) word. With a negative
argument, uppercase the previous word, but do not move the cursor.
-'downcase-word (M-l)'
+‘downcase-word (M-l)’
Lowercase the current (or following) word. With a negative
argument, lowercase the previous word, but do not move the cursor.
-'capitalize-word (M-c)'
+‘capitalize-word (M-c)’
Capitalize the current (or following) word. With a negative
argument, capitalize the previous word, but do not move the cursor.
-'overwrite-mode ()'
+‘overwrite-mode ()’
Toggle overwrite mode. With an explicit positive numeric argument,
switches to overwrite mode. With an explicit non-positive numeric
argument, switches to insert mode. This command affects only
- 'emacs' mode; 'vi' mode does overwrite differently. Each call to
- 'readline()' starts in insert mode.
+ ‘emacs’ mode; ‘vi’ mode does overwrite differently. Each call to
+ ‘readline()’ starts in insert mode.
- In overwrite mode, characters bound to 'self-insert' replace the
+ In overwrite mode, characters bound to ‘self-insert’ replace the
text at point rather than pushing the text to the right.
- Characters bound to 'backward-delete-char' replace the character
+ Characters bound to ‘backward-delete-char’ replace the character
before point with a space.
By default, this command is unbound.
8.4.4 Killing And Yanking
-------------------------
-'kill-line (C-k)'
+‘kill-line (C-k)’
Kill the text from point to the end of the line. With a negative
numeric argument, kill backward from the cursor to the beginning of
the current line.
-'backward-kill-line (C-x Rubout)'
+‘backward-kill-line (C-x Rubout)’
Kill backward from the cursor to the beginning of the current line.
With a negative numeric argument, kill forward from the cursor to
the end of the current line.
-'unix-line-discard (C-u)'
+‘unix-line-discard (C-u)’
Kill backward from the cursor to the beginning of the current line.
-'kill-whole-line ()'
+‘kill-whole-line ()’
Kill all characters on the current line, no matter where point is.
By default, this is unbound.
-'kill-word (M-d)'
+‘kill-word (M-d)’
Kill from point to the end of the current word, or if between
words, to the end of the next word. Word boundaries are the same
- as 'forward-word'.
+ as ‘forward-word’.
-'backward-kill-word (M-<DEL>)'
+‘backward-kill-word (M-<DEL>)’
Kill the word behind point. Word boundaries are the same as
- 'backward-word'.
+ ‘backward-word’.
-'shell-kill-word (M-C-d)'
+‘shell-kill-word (M-C-d)’
Kill from point to the end of the current word, or if between
words, to the end of the next word. Word boundaries are the same
- as 'shell-forward-word'.
+ as ‘shell-forward-word’.
-'shell-backward-kill-word ()'
+‘shell-backward-kill-word ()’
Kill the word behind point. Word boundaries are the same as
- 'shell-backward-word'.
+ ‘shell-backward-word’.
-'unix-word-rubout (C-w)'
+‘unix-word-rubout (C-w)’
Kill the word behind point, using white space as a word boundary.
The killed text is saved on the kill-ring.
-'unix-filename-rubout ()'
+‘unix-filename-rubout ()’
Kill the word behind point, using white space and the slash
character as the word boundaries. The killed text is saved on the
kill-ring.
-'delete-horizontal-space ()'
+‘delete-horizontal-space ()’
Delete all spaces and tabs around point. By default, this is
unbound.
-'kill-region ()'
+‘kill-region ()’
Kill the text in the current region. By default, this command is
unbound.
-'copy-region-as-kill ()'
+‘copy-region-as-kill ()’
Copy the text in the region to the kill buffer, so it can be yanked
right away. By default, this command is unbound.
-'copy-backward-word ()'
+‘copy-backward-word ()’
Copy the word before point to the kill buffer. The word boundaries
- are the same as 'backward-word'. By default, this command is
+ are the same as ‘backward-word’. By default, this command is
unbound.
-'copy-forward-word ()'
+‘copy-forward-word ()’
Copy the word following point to the kill buffer. The word
- boundaries are the same as 'forward-word'. By default, this
+ boundaries are the same as ‘forward-word’. By default, this
command is unbound.
-'yank (C-y)'
+‘yank (C-y)’
Yank the top of the kill ring into the buffer at point.
-'yank-pop (M-y)'
+‘yank-pop (M-y)’
Rotate the kill-ring, and yank the new top. You can only do this
- if the prior command is 'yank' or 'yank-pop'.
+ if the prior command is ‘yank’ or ‘yank-pop’.
\1f
File: bashref.info, Node: Numeric Arguments, Next: Commands For Completion, Prev: Commands For Killing, Up: Bindable Readline Commands
8.4.5 Specifying Numeric Arguments
----------------------------------
-'digit-argument (M-0, M-1, ... M--)'
+‘digit-argument (M-0, M-1, ... M--)’
Add this digit to the argument already accumulating, or start a new
- argument. 'M--' starts a negative argument.
+ argument. ‘M--’ starts a negative argument.
-'universal-argument ()'
+‘universal-argument ()’
This is another way to specify an argument. If this command is
followed by one or more digits, optionally with a leading minus
sign, those digits define the argument. If the command is followed
- by digits, executing 'universal-argument' again ends the numeric
+ by digits, executing ‘universal-argument’ again ends the numeric
argument, but is otherwise ignored. As a special case, if this
command is immediately followed by a character that is neither a
digit nor minus sign, the argument count for the next command is
8.4.6 Letting Readline Type For You
-----------------------------------
-'complete (<TAB>)'
+‘complete (<TAB>)’
Attempt to perform completion on the text before point. The actual
completion performed is application-specific. Bash attempts
completion treating the text as a variable (if the text begins with
- '$'), username (if the text begins with '~'), hostname (if the text
- begins with '@'), or command (including aliases and functions) in
+ ‘$’), username (if the text begins with ‘~’), hostname (if the text
+ begins with ‘@’), or command (including aliases and functions) in
turn. If none of these produces a match, filename completion is
attempted.
-'possible-completions (M-?)'
+‘possible-completions (M-?)’
List the possible completions of the text before point. When
displaying completions, Readline sets the number of columns used
- for display to the value of 'completion-display-width', the value
- of the environment variable 'COLUMNS', or the screen width, in that
+ for display to the value of ‘completion-display-width’, the value
+ of the environment variable ‘COLUMNS’, or the screen width, in that
order.
-'insert-completions (M-*)'
+‘insert-completions (M-*)’
Insert all completions of the text before point that would have
- been generated by 'possible-completions'.
+ been generated by ‘possible-completions’.
-'menu-complete ()'
- Similar to 'complete', but replaces the word to be completed with a
+‘menu-complete ()’
+ Similar to ‘complete’, but replaces the word to be completed with a
single match from the list of possible completions. Repeated
- execution of 'menu-complete' steps through the list of possible
+ execution of ‘menu-complete’ steps through the list of possible
completions, inserting each match in turn. At the end of the list
of completions, the bell is rung (subject to the setting of
- 'bell-style') and the original text is restored. An argument of N
+ ‘bell-style’) and the original text is restored. An argument of N
moves N positions forward in the list of matches; a negative
argument may be used to move backward through the list. This
command is intended to be bound to <TAB>, but is unbound by
default.
-'menu-complete-backward ()'
- Identical to 'menu-complete', but moves backward through the list
- of possible completions, as if 'menu-complete' had been given a
+‘menu-complete-backward ()’
+ Identical to ‘menu-complete’, but moves backward through the list
+ of possible completions, as if ‘menu-complete’ had been given a
negative argument.
-'delete-char-or-list ()'
+‘delete-char-or-list ()’
Deletes the character under the cursor if not at the beginning or
- end of the line (like 'delete-char'). If at the end of the line,
- behaves identically to 'possible-completions'. This command is
+ end of the line (like ‘delete-char’). If at the end of the line,
+ behaves identically to ‘possible-completions’. This command is
unbound by default.
-'complete-filename (M-/)'
+‘complete-filename (M-/)’
Attempt filename completion on the text before point.
-'possible-filename-completions (C-x /)'
+‘possible-filename-completions (C-x /)’
List the possible completions of the text before point, treating it
as a filename.
-'complete-username (M-~)'
+‘complete-username (M-~)’
Attempt completion on the text before point, treating it as a
username.
-'possible-username-completions (C-x ~)'
+‘possible-username-completions (C-x ~)’
List the possible completions of the text before point, treating it
as a username.
-'complete-variable (M-$)'
+‘complete-variable (M-$)’
Attempt completion on the text before point, treating it as a shell
variable.
-'possible-variable-completions (C-x $)'
+‘possible-variable-completions (C-x $)’
List the possible completions of the text before point, treating it
as a shell variable.
-'complete-hostname (M-@)'
+‘complete-hostname (M-@)’
Attempt completion on the text before point, treating it as a
hostname.
-'possible-hostname-completions (C-x @)'
+‘possible-hostname-completions (C-x @)’
List the possible completions of the text before point, treating it
as a hostname.
-'complete-command (M-!)'
+‘complete-command (M-!)’
Attempt completion on the text before point, treating it as a
command name. Command completion attempts to match the text
against aliases, reserved words, shell functions, shell builtins,
and finally executable filenames, in that order.
-'possible-command-completions (C-x !)'
+‘possible-command-completions (C-x !)’
List the possible completions of the text before point, treating it
as a command name.
-'dynamic-complete-history (M-<TAB>)'
+‘dynamic-complete-history (M-<TAB>)’
Attempt completion on the text before point, comparing the text
against lines from the history list for possible completion
matches.
-'dabbrev-expand ()'
+‘dabbrev-expand ()’
Attempt menu completion on the text before point, comparing the
text against lines from the history list for possible completion
matches.
-'complete-into-braces (M-{)'
+‘complete-into-braces (M-{)’
Perform filename completion and insert the list of possible
completions enclosed within braces so the list is available to the
shell (*note Brace Expansion::).
8.4.7 Keyboard Macros
---------------------
-'start-kbd-macro (C-x ()'
+‘start-kbd-macro (C-x ()’
Begin saving the characters typed into the current keyboard macro.
-'end-kbd-macro (C-x ))'
+‘end-kbd-macro (C-x ))’
Stop saving the characters typed into the current keyboard macro
and save the definition.
-'call-last-kbd-macro (C-x e)'
+‘call-last-kbd-macro (C-x e)’
Re-execute the last keyboard macro defined, by making the
characters in the macro appear as if typed at the keyboard.
-'print-last-kbd-macro ()'
+‘print-last-kbd-macro ()’
Print the last keyboard macro defined in a format suitable for the
INPUTRC file.
8.4.8 Some Miscellaneous Commands
---------------------------------
-'re-read-init-file (C-x C-r)'
+‘re-read-init-file (C-x C-r)’
Read in the contents of the INPUTRC file, and incorporate any
bindings or variable assignments found there.
-'abort (C-g)'
+‘abort (C-g)’
Abort the current editing command and ring the terminal's bell
- (subject to the setting of 'bell-style').
+ (subject to the setting of ‘bell-style’).
-'do-lowercase-version (M-A, M-B, M-X, ...)'
+‘do-lowercase-version (M-A, M-B, M-X, ...)’
If the metafied character X is upper case, run the command that is
bound to the corresponding metafied lower case character. The
behavior is undefined if X is already lower case.
-'prefix-meta (<ESC>)'
+‘prefix-meta (<ESC>)’
Metafy the next character typed. This is for keyboards without a
- meta key. Typing '<ESC> f' is equivalent to typing 'M-f'.
+ meta key. Typing ‘<ESC> f’ is equivalent to typing ‘M-f’.
-'undo (C-_ or C-x C-u)'
+‘undo (C-_ or C-x C-u)’
Incremental undo, separately remembered for each line.
-'revert-line (M-r)'
+‘revert-line (M-r)’
Undo all changes made to this line. This is like executing the
- 'undo' command enough times to get back to the beginning.
+ ‘undo’ command enough times to get back to the beginning.
-'tilde-expand (M-&)'
+‘tilde-expand (M-&)’
Perform tilde expansion on the current word.
-'set-mark (C-@)'
+‘set-mark (C-@)’
Set the mark to the point. If a numeric argument is supplied, the
mark is set to that position.
-'exchange-point-and-mark (C-x C-x)'
+‘exchange-point-and-mark (C-x C-x)’
Swap the point with the mark. The current cursor position is set
to the saved position, and the old cursor position is saved as the
mark.
-'character-search (C-])'
+‘character-search (C-])’
A character is read and point is moved to the next occurrence of
that character. A negative argument searches for previous
occurrences.
-'character-search-backward (M-C-])'
+‘character-search-backward (M-C-])’
A character is read and point is moved to the previous occurrence
of that character. A negative argument searches for subsequent
occurrences.
-'skip-csi-sequence ()'
+‘skip-csi-sequence ()’
Read enough characters to consume a multi-key sequence such as
those defined for keys like Home and End. Such sequences begin
with a Control Sequence Indicator (CSI), usually ESC-[. If this
inserting stray characters into the editing buffer. This is
unbound by default, but usually bound to ESC-[.
-'insert-comment (M-#)'
- Without a numeric argument, the value of the 'comment-begin'
+‘insert-comment (M-#)’
+ Without a numeric argument, the value of the ‘comment-begin’
variable is inserted at the beginning of the current line. If a
numeric argument is supplied, this command acts as a toggle: if the
characters at the beginning of the line do not match the value of
- 'comment-begin', the value is inserted, otherwise the characters in
- 'comment-begin' are deleted from the beginning of the line. In
+ ‘comment-begin’, the value is inserted, otherwise the characters in
+ ‘comment-begin’ are deleted from the beginning of the line. In
either case, the line is accepted as if a newline had been typed.
- The default value of 'comment-begin' causes this command to make
+ The default value of ‘comment-begin’ causes this command to make
the current line a shell comment. If a numeric argument causes the
comment character to be removed, the line will be executed by the
shell.
-'dump-functions ()'
+‘dump-functions ()’
Print all of the functions and their key bindings to the Readline
output stream. If a numeric argument is supplied, the output is
formatted in such a way that it can be made part of an INPUTRC
file. This command is unbound by default.
-'dump-variables ()'
+‘dump-variables ()’
Print all of the settable variables and their values to the
Readline output stream. If a numeric argument is supplied, the
output is formatted in such a way that it can be made part of an
INPUTRC file. This command is unbound by default.
-'dump-macros ()'
+‘dump-macros ()’
Print all of the Readline key sequences bound to macros and the
strings they output. If a numeric argument is supplied, the output
is formatted in such a way that it can be made part of an INPUTRC
file. This command is unbound by default.
-'spell-correct-word (C-x s)'
+‘spell-correct-word (C-x s)’
Perform spelling correction on the current word, treating it as a
- directory or filename, in the same way as the 'cdspell' shell
+ directory or filename, in the same way as the ‘cdspell’ shell
option. Word boundaries are the same as those used by
- 'shell-forward-word'.
+ ‘shell-forward-word’.
-'glob-complete-word (M-g)'
+‘glob-complete-word (M-g)’
The word before point is treated as a pattern for pathname
expansion, with an asterisk implicitly appended. This pattern is
used to generate a list of matching file names for possible
completions.
-'glob-expand-word (C-x *)'
+‘glob-expand-word (C-x *)’
The word before point is treated as a pattern for pathname
expansion, and the list of matching file names is inserted,
- replacing the word. If a numeric argument is supplied, a '*' is
+ replacing the word. If a numeric argument is supplied, a ‘*’ is
appended before pathname expansion.
-'glob-list-expansions (C-x g)'
+‘glob-list-expansions (C-x g)’
The list of expansions that would have been generated by
- 'glob-expand-word' is displayed, and the line is redrawn. If a
- numeric argument is supplied, a '*' is appended before pathname
+ ‘glob-expand-word’ is displayed, and the line is redrawn. If a
+ numeric argument is supplied, a ‘*’ is appended before pathname
expansion.
-'display-shell-version (C-x C-v)'
+‘display-shell-version (C-x C-v)’
Display version information about the current instance of Bash.
-'shell-expand-line (M-C-e)'
+‘shell-expand-line (M-C-e)’
Expand the line by performing shell word expansions. This performs
alias and history expansion, $'STRING' and $"STRING" quoting, tilde
expansion, parameter and variable expansion, arithmetic expansion,
- word splitting, and quote removal.
+ command and proces substitution, word splitting, and quote removal.
+ An explicit argument suppresses command and process substitution.
-'history-expand-line (M-^)'
+‘history-expand-line (M-^)’
Perform history expansion on the current line.
-'magic-space ()'
+‘magic-space ()’
Perform history expansion on the current line and insert a space
(*note History Interaction::).
-'alias-expand-line ()'
+‘alias-expand-line ()’
Perform alias expansion on the current line (*note Aliases::).
-'history-and-alias-expand-line ()'
+‘history-and-alias-expand-line ()’
Perform history and alias expansion on the current line.
-'insert-last-argument (M-. or M-_)'
- A synonym for 'yank-last-arg'.
+‘insert-last-argument (M-. or M-_)’
+ A synonym for ‘yank-last-arg’.
-'edit-and-execute-command (C-x C-e)'
+‘edit-and-execute-command (C-x C-e)’
Invoke an editor on the current command line, and execute the
- result as shell commands. Bash attempts to invoke '$VISUAL',
- '$EDITOR', and 'emacs' as the editor, in that order.
+ result as shell commands. Bash attempts to invoke ‘$VISUAL’,
+ ‘$EDITOR’, and ‘emacs’ as the editor, in that order.
-'execute-named-command (M-x)'
+‘execute-named-command (M-x)’
Read a bindable readline command name from the input and execute
the function to which it's bound, as if the key sequence to which
it was bound appeared in the input. If this function is supplied
8.5 Readline vi Mode
====================
-While the Readline library does not have a full set of 'vi' editing
+While the Readline library does not have a full set of ‘vi’ editing
functions, it does contain enough to allow simple editing of the line.
-The Readline 'vi' mode behaves as specified in the POSIX standard.
+The Readline ‘vi’ mode behaves as specified in the POSIX standard.
- In order to switch interactively between 'emacs' and 'vi' editing
-modes, use the 'set -o emacs' and 'set -o vi' commands (*note The Set
-Builtin::). The Readline default is 'emacs' mode.
+ In order to switch interactively between ‘emacs’ and ‘vi’ editing
+modes, use the ‘set -o emacs’ and ‘set -o vi’ commands (*note The Set
+Builtin::). The Readline default is ‘emacs’ mode.
- When you enter a line in 'vi' mode, you are already placed in
-'insertion' mode, as if you had typed an 'i'. Pressing <ESC> switches
+ When you enter a line in ‘vi’ mode, you are already placed in
+'insertion' mode, as if you had typed an ‘i’. Pressing <ESC> switches
you into 'command' mode, where you can edit the text of the line with
-the standard 'vi' movement keys, move to previous history lines with 'k'
-and subsequent lines with 'j', and so forth.
+the standard ‘vi’ movement keys, move to previous history lines with ‘k’
+and subsequent lines with ‘j’, and so forth.
\1f
File: bashref.info, Node: Programmable Completion, Next: Programmable Completion Builtins, Prev: Readline vi Mode, Up: Command Line Editing
When word completion is attempted for an argument to a command for which
a completion specification (a COMPSPEC) has been defined using the
-'complete' builtin (*note Programmable Completion Builtins::), the
+‘complete’ builtin (*note Programmable Completion Builtins::), the
programmable completion facilities are invoked.
First, the command name is identified. If a compspec has been
defined for that command, the compspec is used to generate the list of
possible completions for the word. If the command word is the empty
string (completion attempted at the beginning of an empty line), any
-compspec defined with the '-E' option to 'complete' is used. If the
+compspec defined with the ‘-E’ option to ‘complete’ is used. If the
command word is a full pathname, a compspec for the full pathname is
searched for first. If no compspec is found for the full pathname, an
attempt is made to find a compspec for the portion following the final
slash. If those searches do not result in a compspec, any compspec
-defined with the '-D' option to 'complete' is used as the default. If
+defined with the ‘-D’ option to ‘complete’ is used as the default. If
there is no default compspec, Bash attempts alias expansion on the
command word as a final resort, and attempts to find a compspec for the
command word from any successful expansion
First, the actions specified by the compspec are used. Only matches
which are prefixed by the word being completed are returned. When the
-'-f' or '-d' option is used for filename or directory name completion,
-the shell variable 'FIGNORE' is used to filter the matches. *Note Bash
-Variables::, for a description of 'FIGNORE'.
+‘-f’ or ‘-d’ option is used for filename or directory name completion,
+the shell variable ‘FIGNORE’ is used to filter the matches. *Note Bash
+Variables::, for a description of ‘FIGNORE’.
- Any completions specified by a filename expansion pattern to the '-G'
+ Any completions specified by a filename expansion pattern to the ‘-G’
option are generated next. The words generated by the pattern need not
-match the word being completed. The 'GLOBIGNORE' shell variable is not
-used to filter the matches, but the 'FIGNORE' shell variable is used.
+match the word being completed. The ‘GLOBIGNORE’ shell variable is not
+used to filter the matches, but the ‘FIGNORE’ shell variable is used.
- Next, the string specified as the argument to the '-W' option is
-considered. The string is first split using the characters in the 'IFS'
+ Next, the string specified as the argument to the ‘-W’ option is
+considered. The string is first split using the characters in the ‘IFS’
special variable as delimiters. Shell quoting is honored within the
string, in order to provide a mechanism for the words to contain shell
-metacharacters or characters in the value of 'IFS'. Each word is then
+metacharacters or characters in the value of ‘IFS’. Each word is then
expanded using brace expansion, tilde expansion, parameter and variable
expansion, command substitution, and arithmetic expansion, as described
above (*note Shell Expansions::). The results are split using the rules
words become the possible completions.
After these matches have been generated, any shell function or
-command specified with the '-F' and '-C' options is invoked. When the
-command or function is invoked, the 'COMP_LINE', 'COMP_POINT',
-'COMP_KEY', and 'COMP_TYPE' variables are assigned values as described
+command specified with the ‘-F’ and ‘-C’ options is invoked. When the
+command or function is invoked, the ‘COMP_LINE’, ‘COMP_POINT’,
+‘COMP_KEY’, and ‘COMP_TYPE’ variables are assigned values as described
above (*note Bash Variables::). If a shell function is being invoked,
-the 'COMP_WORDS' and 'COMP_CWORD' variables are also set. When the
+the ‘COMP_WORDS’ and ‘COMP_CWORD’ variables are also set. When the
function or command is invoked, the first argument ($1) is the name of
the command whose arguments are being completed, the second argument
($2) is the word being completed, and the third argument ($3) is the
is performed; the function or command has complete freedom in generating
the matches.
- Any function specified with '-F' is invoked first. The function may
-use any of the shell facilities, including the 'compgen' and 'compopt'
+ Any function specified with ‘-F’ is invoked first. The function may
+use any of the shell facilities, including the ‘compgen’ and ‘compopt’
builtins described below (*note Programmable Completion Builtins::), to
generate the matches. It must put the possible completions in the
-'COMPREPLY' array variable, one per array element.
+‘COMPREPLY’ array variable, one per array element.
- Next, any command specified with the '-C' option is invoked in an
+ Next, any command specified with the ‘-C’ option is invoked in an
environment equivalent to command substitution. It should print a list
of completions, one per line, to the standard output. Backslash may be
used to escape a newline, if necessary.
After all of the possible completions are generated, any filter
-specified with the '-X' option is applied to the list. The filter is a
-pattern as used for pathname expansion; a '&' in the pattern is replaced
-with the text of the word being completed. A literal '&' may be escaped
+specified with the ‘-X’ option is applied to the list. The filter is a
+pattern as used for pathname expansion; a ‘&’ in the pattern is replaced
+with the text of the word being completed. A literal ‘&’ may be escaped
with a backslash; the backslash is removed before attempting a match.
Any completion that matches the pattern will be removed from the list.
-A leading '!' negates the pattern; in this case any completion not
-matching the pattern will be removed. If the 'nocasematch' shell option
-(see the description of 'shopt' in *note The Shopt Builtin::) is
+A leading ‘!’ negates the pattern; in this case any completion not
+matching the pattern will be removed. If the ‘nocasematch’ shell option
+(see the description of ‘shopt’ in *note The Shopt Builtin::) is
enabled, the match is performed without regard to the case of alphabetic
characters.
- Finally, any prefix and suffix specified with the '-P' and '-S'
+ Finally, any prefix and suffix specified with the ‘-P’ and ‘-S’
options are added to each member of the completion list, and the result
is returned to the Readline completion code as the list of possible
completions.
If the previously-applied actions do not generate any matches, and
-the '-o dirnames' option was supplied to 'complete' when the compspec
+the ‘-o dirnames’ option was supplied to ‘complete’ when the compspec
was defined, directory name completion is attempted.
- If the '-o plusdirs' option was supplied to 'complete' when the
+ If the ‘-o plusdirs’ option was supplied to ‘complete’ when the
compspec was defined, directory name completion is attempted and any
matches are added to the results of the other actions.
By default, if a compspec is found, whatever it generates is returned
to the completion code as the full set of possible completions. The
default Bash completions are not attempted, and the Readline default of
-filename completion is disabled. If the '-o bashdefault' option was
-supplied to 'complete' when the compspec was defined, the default Bash
+filename completion is disabled. If the ‘-o bashdefault’ option was
+supplied to ‘complete’ when the compspec was defined, the default Bash
completions are attempted if the compspec generates no matches. If the
-'-o default' option was supplied to 'complete' when the compspec was
+‘-o default’ option was supplied to ‘complete’ when the compspec was
defined, Readline's default completion will be performed if the compspec
(and, if attempted, the default Bash completions) generate no matches.
There is some support for dynamically modifying completions. This is
most useful when used in combination with a default completion specified
-with '-D'. It's possible for shell functions executed as completion
+with ‘-D’. It's possible for shell functions executed as completion
handlers to indicate that completion should be retried by returning an
exit status of 124. If a shell function returns 124, and changes the
compspec associated with the command on which completion is being
command are to be completed, and two to modify the completion as it is
happening.
-'compgen'
+‘compgen’
compgen [-V VARNAME] [OPTION] [WORD]
Generate possible completion matches for WORD according to the
- OPTIONs, which may be any option accepted by the 'complete' builtin
- with the exceptions of '-p', '-r', '-D', '-E', and '-I', and write
+ OPTIONs, which may be any option accepted by the ‘complete’ builtin
+ with the exceptions of ‘-p’, ‘-r’, ‘-D’, ‘-E’, and ‘-I’, and write
the matches to the standard output.
- If the '-V' option is supplied, 'compgen' stores the generated
+ If the ‘-V’ option is supplied, ‘compgen’ stores the generated
completions into the indexed array variable VARNAME instead of
writing them to the standard output.
- When using the '-F' or '-C' options, the various shell variables
+ When using the ‘-F’ or ‘-C’ options, the various shell variables
set by the programmable completion facilities, while available,
will not have useful values.
The return value is true unless an invalid option is supplied, or
no matches were generated.
-'complete'
+‘complete’
complete [-abcdefgjksuv] [-o COMP-OPTION] [-DEI] [-A ACTION]
[-G GLOBPAT] [-W WORDLIST] [-F FUNCTION] [-C COMMAND]
[-X FILTERPAT] [-P PREFIX] [-S SUFFIX] NAME [NAME ...]
complete -pr [-DEI] [NAME ...]
Specify how arguments to each NAME should be completed. If the
- '-p' option is supplied, or if no options are supplied, existing
- completion specifications are printed in a way that allows them to
- be reused as input. The '-r' option removes a completion
+ ‘-p’ option is supplied, or if no options or NAMEs are supplied,
+ existing completion specifications are printed in a way that allows
+ them to be reused as input. The ‘-r’ option removes a completion
specification for each NAME, or, if no NAMEs are supplied, all
- completion specifications. The '-D' option indicates that other
+ completion specifications. The ‘-D’ option indicates that other
supplied options and actions should apply to the "default" command
completion; that is, completion attempted on a command for which no
- completion has previously been defined. The '-E' option indicates
+ completion has previously been defined. The ‘-E’ option indicates
that other supplied options and actions should apply to "empty"
command completion; that is, completion attempted on a blank line.
- The '-I' option indicates that other supplied options and actions
+ The ‘-I’ option indicates that other supplied options and actions
should apply to completion on the initial non-assignment word on
- the line, or after a command delimiter such as ';' or '|', which is
+ the line, or after a command delimiter such as ‘;’ or ‘|’, which is
usually command name completion. If multiple options are supplied,
- the '-D' option takes precedence over '-E', and both take
- precedence over '-I'. If any of '-D', '-E', or '-I' are supplied,
+ the ‘-D’ option takes precedence over ‘-E’, and both take
+ precedence over ‘-I’. If any of ‘-D’, ‘-E’, or ‘-I’ are supplied,
any other NAME arguments are ignored; these completions only apply
to the case specified by the option.
Completion::).
Other options, if specified, have the following meanings. The
- arguments to the '-G', '-W', and '-X' options (and, if necessary,
- the '-P' and '-S' options) should be quoted to protect them from
- expansion before the 'complete' builtin is invoked.
+ arguments to the ‘-G’, ‘-W’, and ‘-X’ options (and, if necessary,
+ the ‘-P’ and ‘-S’ options) should be quoted to protect them from
+ expansion before the ‘complete’ builtin is invoked.
- '-o COMP-OPTION'
+ ‘-o COMP-OPTION’
The COMP-OPTION controls several aspects of the compspec's
behavior beyond the simple generation of completions.
COMP-OPTION may be one of:
- 'bashdefault'
+ ‘bashdefault’
Perform the rest of the default Bash completions if the
compspec generates no matches.
- 'default'
+ ‘default’
Use Readline's default filename completion if the
compspec generates no matches.
- 'dirnames'
+ ‘dirnames’
Perform directory name completion if the compspec
generates no matches.
- 'filenames'
+ ‘filenames’
Tell Readline that the compspec generates filenames, so
it can perform any filename-specific processing (like
adding a slash to directory names, quoting special
characters, or suppressing trailing spaces). This option
is intended to be used with shell functions specified
- with '-F'.
+ with ‘-F’.
- 'fullquote'
+ ‘fullquote’
Tell Readline to quote all the completed words even if
they are not filenames.
- 'noquote'
+ ‘noquote’
Tell Readline not to quote the completed words if they
are filenames (quoting filenames is the default).
- 'nosort'
+ ‘nosort’
Tell Readline not to sort the list of possible
completions alphabetically.
- 'nospace'
+ ‘nospace’
Tell Readline not to append a space (the default) to
words completed at the end of the line.
- 'plusdirs'
+ ‘plusdirs’
After any matches defined by the compspec are generated,
directory name completion is attempted and any matches
are added to the results of the other actions.
- '-A ACTION'
+ ‘-A ACTION’
The ACTION may be one of the following to generate a list of
possible completions:
- 'alias'
- Alias names. May also be specified as '-a'.
+ ‘alias’
+ Alias names. May also be specified as ‘-a’.
- 'arrayvar'
+ ‘arrayvar’
Array variable names.
- 'binding'
+ ‘binding’
Readline key binding names (*note Bindable Readline
Commands::).
- 'builtin'
+ ‘builtin’
Names of shell builtin commands. May also be specified
- as '-b'.
+ as ‘-b’.
- 'command'
- Command names. May also be specified as '-c'.
+ ‘command’
+ Command names. May also be specified as ‘-c’.
- 'directory'
- Directory names. May also be specified as '-d'.
+ ‘directory’
+ Directory names. May also be specified as ‘-d’.
- 'disabled'
+ ‘disabled’
Names of disabled shell builtins.
- 'enabled'
+ ‘enabled’
Names of enabled shell builtins.
- 'export'
+ ‘export’
Names of exported shell variables. May also be specified
- as '-e'.
+ as ‘-e’.
- 'file'
- File names. May also be specified as '-f'.
+ ‘file’
+ File names. May also be specified as ‘-f’.
- 'function'
+ ‘function’
Names of shell functions.
- 'group'
- Group names. May also be specified as '-g'.
+ ‘group’
+ Group names. May also be specified as ‘-g’.
- 'helptopic'
- Help topics as accepted by the 'help' builtin (*note Bash
+ ‘helptopic’
+ Help topics as accepted by the ‘help’ builtin (*note Bash
Builtins::).
- 'hostname'
+ ‘hostname’
Hostnames, as taken from the file specified by the
- 'HOSTFILE' shell variable (*note Bash Variables::).
+ ‘HOSTFILE’ shell variable (*note Bash Variables::).
- 'job'
+ ‘job’
Job names, if job control is active. May also be
- specified as '-j'.
+ specified as ‘-j’.
- 'keyword'
- Shell reserved words. May also be specified as '-k'.
+ ‘keyword’
+ Shell reserved words. May also be specified as ‘-k’.
- 'running'
+ ‘running’
Names of running jobs, if job control is active.
- 'service'
- Service names. May also be specified as '-s'.
+ ‘service’
+ Service names. May also be specified as ‘-s’.
- 'setopt'
- Valid arguments for the '-o' option to the 'set' builtin
+ ‘setopt’
+ Valid arguments for the ‘-o’ option to the ‘set’ builtin
(*note The Set Builtin::).
- 'shopt'
- Shell option names as accepted by the 'shopt' builtin
+ ‘shopt’
+ Shell option names as accepted by the ‘shopt’ builtin
(*note Bash Builtins::).
- 'signal'
+ ‘signal’
Signal names.
- 'stopped'
+ ‘stopped’
Names of stopped jobs, if job control is active.
- 'user'
- User names. May also be specified as '-u'.
+ ‘user’
+ User names. May also be specified as ‘-u’.
- 'variable'
+ ‘variable’
Names of all shell variables. May also be specified as
- '-v'.
+ ‘-v’.
- '-C COMMAND'
+ ‘-C COMMAND’
COMMAND is executed in a subshell environment, and its output
is used as the possible completions. Arguments are passed as
- with the '-F' option.
+ with the ‘-F’ option.
- '-F FUNCTION'
+ ‘-F FUNCTION’
The shell function FUNCTION is executed in the current shell
environment. When it is executed, $1 is the name of the
command whose arguments are being completed, $2 is the word
being completed, and $3 is the word preceding the word being
completed, as described above (*note Programmable
Completion::). When it finishes, the possible completions are
- retrieved from the value of the 'COMPREPLY' array variable.
+ retrieved from the value of the ‘COMPREPLY’ array variable.
- '-G GLOBPAT'
+ ‘-G GLOBPAT’
The filename expansion pattern GLOBPAT is expanded to generate
the possible completions.
- '-P PREFIX'
+ ‘-P PREFIX’
PREFIX is added at the beginning of each possible completion
after all other options have been applied.
- '-S SUFFIX'
+ ‘-S SUFFIX’
SUFFIX is appended to each possible completion after all other
options have been applied.
- '-W WORDLIST'
- The WORDLIST is split using the characters in the 'IFS'
+ ‘-W WORDLIST’
+ The WORDLIST is split using the characters in the ‘IFS’
special variable as delimiters, and each resultant word is
expanded. The possible completions are the members of the
resultant list which match the word being completed.
- '-X FILTERPAT'
+ ‘-X FILTERPAT’
FILTERPAT is a pattern as used for filename expansion. It is
applied to the list of possible completions generated by the
preceding options and arguments, and each completion matching
- FILTERPAT is removed from the list. A leading '!' in
+ FILTERPAT is removed from the list. A leading ‘!’ in
FILTERPAT negates the pattern; in this case, any completion
not matching FILTERPAT is removed.
The return value is true unless an invalid option is supplied, an
- option other than '-p', '-r', '-D', '-E', or '-I' is supplied
+ option other than ‘-p’, ‘-r’, ‘-D’, ‘-E’, or ‘-I’ is supplied
without a NAME argument, an attempt is made to remove a completion
specification for a NAME for which no specification exists, or an
error occurs adding a completion specification.
-'compopt'
+‘compopt’
compopt [-o OPTION] [-DEI] [+o OPTION] [NAME]
Modify completion options for each NAME according to the OPTIONs,
or for the currently-executing completion if no NAMEs are supplied.
If no OPTIONs are given, display the completion options for each
NAME or the current completion. The possible values of OPTION are
- those valid for the 'complete' builtin described above. The '-D'
+ those valid for the ‘complete’ builtin described above. The ‘-D’
option indicates that other supplied options should apply to the
"default" command completion; that is, completion attempted on a
command for which no completion has previously been defined. The
- '-E' option indicates that other supplied options should apply to
+ ‘-E’ option indicates that other supplied options should apply to
"empty" command completion; that is, completion attempted on a
- blank line. The '-I' option indicates that other supplied options
+ blank line. The ‘-I’ option indicates that other supplied options
should apply to completion on the initial non-assignment word on
- the line, or after a command delimiter such as ';' or '|', which is
+ the line, or after a command delimiter such as ‘;’ or ‘|’, which is
usually command name completion.
- If multiple options are supplied, the '-D' option takes precedence
- over '-E', and both take precedence over '-I'
+ If multiple options are supplied, the ‘-D’ option takes precedence
+ over ‘-E’, and both take precedence over ‘-I’
The return value is true unless an invalid option is supplied, an
attempt is made to modify the options for a NAME for which no
=====================================
The most common way to obtain additional completion functionality beyond
-the default actions 'complete' and 'compgen' provide is to use a shell
-function and bind it to a particular command using 'complete -F'.
+the default actions ‘complete’ and ‘compgen’ provide is to use a shell
+function and bind it to a particular command using ‘complete -F’.
- The following function provides completions for the 'cd' builtin. It
+ The following function provides completions for the ‘cd’ builtin. It
is a reasonably good example of what shell functions must do when used
-for completion. This function uses the word passed as '$2' to determine
-the directory name to complete. You can also use the 'COMP_WORDS' array
-variable; the current word is indexed by the 'COMP_CWORD' variable.
+for completion. This function uses the word passed as ‘$2’ to determine
+the directory name to complete. You can also use the ‘COMP_WORDS’ array
+variable; the current word is indexed by the ‘COMP_CWORD’ variable.
- The function relies on the 'complete' and 'compgen' builtins to do
-much of the work, adding only the things that the Bash 'cd' does beyond
+ The function relies on the ‘complete’ and ‘compgen’ builtins to do
+much of the work, adding only the things that the Bash ‘cd’ does beyond
accepting basic directory names: tilde expansion (*note Tilde
Expansion::), searching directories in $CDPATH, which is described above
-(*note Bourne Shell Builtins::), and basic support for the 'cdable_vars'
-shell option (*note The Shopt Builtin::). '_comp_cd' modifies the value
+(*note Bourne Shell Builtins::), and basic support for the ‘cdable_vars’
+shell option (*note The Shopt Builtin::). ‘_comp_cd’ modifies the value
of IFS so that it contains only a newline to accommodate file names
-containing spaces and tabs - 'compgen' prints the possible completions
+containing spaces and tabs - ‘compgen’ prints the possible completions
it generates one per line.
Possible completions go into the COMPREPLY array variable, one
return 0
}
- We install the completion function using the '-F' option to
-'complete':
+ We install the completion function using the ‘-F’ option to
+‘complete’:
# Tell readline to quote appropriate and append slashes to directories;
# use the bash default completion for other arguments
Since we'd like Bash and Readline to take care of some of the other
details for us, we use several other options to tell Bash and Readline
-what to do. The '-o filenames' option tells Readline that the possible
+what to do. The ‘-o filenames’ option tells Readline that the possible
completions should be treated as filenames, and quoted appropriately.
That option will also cause Readline to append a slash to filenames it
can determine are directories (which is why we might want to extend
-'_comp_cd' to append a slash if we're using directories found via
-CDPATH: Readline can't tell those completions are directories). The '-o
-nospace' option tells Readline to not append a space character to the
-directory name, in case we want to append to it. The '-o bashdefault'
+‘_comp_cd’ to append a slash if we're using directories found via
+CDPATH: Readline can't tell those completions are directories). The ‘-o
+nospace’ option tells Readline to not append a space character to the
+directory name, in case we want to append to it. The ‘-o bashdefault’
option brings in the rest of the "Bash default" completions - possible
completions that Bash adds to the default Readline set. These include
things like command name completion, variable completion for words
-beginning with '$' or '${', completions containing pathname expansion
+beginning with ‘$’ or ‘${’, completions containing pathname expansion
patterns (*note Filename Expansion::), and so on.
- Once installed using 'complete', '_comp_cd' will be called every time
-we attempt word completion for a 'cd' command.
+ Once installed using ‘complete’, ‘_comp_cd’ will be called every time
+we attempt word completion for a ‘cd’ command.
Many more examples - an extensive collection of completions for most
of the common GNU, Unix, and Linux commands - are available as part of
are ports for other systems such as Solaris and Mac OS X.
An older version of the bash_completion package is distributed with
-bash in the 'examples/complete' subdirectory.
+bash in the ‘examples/complete’ subdirectory.
\1f
File: bashref.info, Node: Using History Interactively, Next: Installing Bash, Prev: Command Line Editing, Up: Top
9.1 Bash History Facilities
===========================
-When the '-o history' option to the 'set' builtin is enabled (*note The
-Set Builtin::), the shell provides access to the "command history", the
-list of commands previously typed. The value of the 'HISTSIZE' shell
+When the ‘-o history’ option to the ‘set’ builtin is enabled (*note The
+Set Builtin::), the shell provides access to the “command history”, the
+list of commands previously typed. The value of the ‘HISTSIZE’ shell
variable is used as the number of commands to save in a history list.
-The text of the last '$HISTSIZE' commands (default 500) is saved. The
+The text of the last ‘$HISTSIZE’ commands (default 500) is saved. The
shell stores each command in the history list prior to parameter and
variable expansion but after history expansion is performed, subject to
-the values of the shell variables 'HISTIGNORE' and 'HISTCONTROL'.
+the values of the shell variables ‘HISTIGNORE’ and ‘HISTCONTROL’.
When the shell starts up, the history is initialized from the file
-named by the 'HISTFILE' variable (default '~/.bash_history'). The file
-named by the value of 'HISTFILE' is truncated, if necessary, to contain
+named by the ‘HISTFILE’ variable (default ‘~/.bash_history’). The file
+named by the value of ‘HISTFILE’ is truncated, if necessary, to contain
no more than the number of lines specified by the value of the
-'HISTFILESIZE' variable. When a shell with history enabled exits, the
-last '$HISTSIZE' lines are copied from the history list to the file
-named by '$HISTFILE'. If the 'histappend' shell option is set (*note
+‘HISTFILESIZE’ variable. When a shell with history enabled exits, the
+last ‘$HISTSIZE’ lines are copied from the history list to the file
+named by ‘$HISTFILE’. If the ‘histappend’ shell option is set (*note
Bash Builtins::), the lines are appended to the history file, otherwise
-the history file is overwritten. If 'HISTFILE' is unset or null, or if
+the history file is overwritten. If ‘HISTFILE’ is unset or null, or if
the history file is unwritable, the history is not saved. After saving
the history, the history file is truncated to contain no more than
-'$HISTFILESIZE' lines. If 'HISTFILESIZE' is unset, or set to null, a
+‘$HISTFILESIZE’ lines. If ‘HISTFILESIZE’ is unset, or set to null, a
non-numeric value, or a numeric value less than zero, the history file
is not truncated.
- If the 'HISTTIMEFORMAT' is set, the time stamp information associated
+ If the ‘HISTTIMEFORMAT’ is set, the time stamp information associated
with each history entry is written to the history file, marked with the
history comment character. When the history file is read, lines
beginning with the history comment character followed immediately by a
digit are interpreted as timestamps for the following history entry.
- The 'fc' builtin command may be used to list or edit and re-execute a
-portion of the history list. The 'history' builtin may be used to
+ The ‘fc’ builtin command may be used to list or edit and re-execute a
+portion of the history list. The ‘history’ builtin may be used to
display or modify the history list and manipulate the history file.
When using command-line editing, search commands are available in each
editing mode that provide access to the history list (*note Commands For
History::).
The shell allows control over which commands are saved on the history
-list. The 'HISTCONTROL' and 'HISTIGNORE' variables are used to cause
-the shell to save only a subset of the commands entered. The 'cmdhist'
+list. The ‘HISTCONTROL’ and ‘HISTIGNORE’ variables are used to cause
+the shell to save only a subset of the commands entered. The ‘cmdhist’
shell option, if enabled, causes the shell to attempt to save each line
of a multi-line command in the same history entry, adding semicolons
-where necessary to preserve syntactic correctness. The 'lithist' shell
+where necessary to preserve syntactic correctness. The ‘lithist’ shell
option causes the shell to save the command with embedded newlines
-instead of semicolons. The 'shopt' builtin is used to set these
-options. *Note The Shopt Builtin::, for a description of 'shopt'.
+instead of semicolons. The ‘shopt’ builtin is used to set these
+options. *Note The Shopt Builtin::, for a description of ‘shopt’.
\1f
File: bashref.info, Node: Bash History Builtins, Next: History Interaction, Prev: Bash History Facilities, Up: Using History Interactively
Bash provides two builtin commands which manipulate the history list and
history file.
-'fc'
+‘fc’
fc [-e ENAME] [-lnr] [FIRST] [LAST]
fc -s [PAT=REP] [COMMAND]
from the current command number).
When listing, a FIRST or LAST of 0 is equivalent to -1 and -0 is
- equivalent to the current command (usually the 'fc' command);
+ equivalent to the current command (usually the ‘fc’ command);
otherwise 0 is equivalent to -1 and -0 is invalid.
If LAST is not specified, it is set to FIRST. If FIRST is not
- specified, it is set to the previous command for editing and -16
- for listing. If the '-l' flag is given, the commands are listed on
- standard output. The '-n' flag suppresses the command numbers when
- listing. The '-r' flag reverses the order of the listing.
+ specified, it is set to the previous command for editing and −16
+ for listing. If the ‘-l’ flag is given, the commands are listed on
+ standard output. The ‘-n’ flag suppresses the command numbers when
+ listing. The ‘-r’ flag reverses the order of the listing.
Otherwise, the editor given by ENAME is invoked on a file
containing those commands. If ENAME is not given, the value of the
- following variable expansion is used: '${FCEDIT:-${EDITOR:-vi}}'.
- This says to use the value of the 'FCEDIT' variable if set, or the
- value of the 'EDITOR' variable if that is set, or 'vi' if neither
+ following variable expansion is used: ‘${FCEDIT:-${EDITOR:-vi}}’.
+ This says to use the value of the ‘FCEDIT’ variable if set, or the
+ value of the ‘EDITOR’ variable if that is set, or ‘vi’ if neither
is set. When editing is complete, the edited commands are echoed
and executed.
PAT in the selected command is replaced by REP. COMMAND is
interpreted the same as FIRST above.
- A useful alias to use with the 'fc' command is 'r='fc -s'', so that
- typing 'r cc' runs the last command beginning with 'cc' and typing
- 'r' re-executes the last command (*note Aliases::).
+ A useful alias to use with the ‘fc’ command is ‘r='fc -s'’, so that
+ typing ‘r cc’ runs the last command beginning with ‘cc’ and typing
+ ‘r’ re-executes the last command (*note Aliases::).
-'history'
+‘history’
history [N]
history -c
history -d OFFSET
history -ps ARG
With no options, display the history list with line numbers. Lines
- prefixed with a '*' have been modified. An argument of N lists
- only the last N lines. If the shell variable 'HISTTIMEFORMAT' is
- set and not null, it is used as a format string for STRFTIME to
- display the time stamp associated with each displayed history
+ prefixed with a ‘*’ have been modified. An argument of N lists
+ only the last N lines. If the shell variable ‘HISTTIMEFORMAT’ is
+ set and not null, it is used as a format string for ‘strftime’(3)
+ to display the time stamp associated with each displayed history
entry. No intervening blank is printed between the formatted time
stamp and the history line.
Options, if supplied, have the following meanings:
- '-c'
+ ‘-c’
Clear the history list. This may be combined with the other
options to replace the history list completely.
- '-d OFFSET'
+ ‘-d OFFSET’
Delete the history entry at position OFFSET. If OFFSET is
positive, it should be specified as it appears when the
history is displayed. If OFFSET is negative, it is
interpreted as relative to one greater than the last history
position, so negative indices count back from the end of the
- history, and an index of '-1' refers to the current 'history
- -d' command.
+ history, and an index of ‘-1’ refers to the current ‘history
+ -d’ command.
- '-d START-END'
+ ‘-d START-END’
Delete the range of history entries between positions START
and END, inclusive. Positive and negative values for START
and END are interpreted as described above.
- '-a'
+ ‘-a’
Append the new history lines to the history file. These are
history lines entered since the beginning of the current Bash
session, but not already appended to the history file.
- '-n'
+ ‘-n’
Append the history lines not already read from the history
file to the current history list. These are lines appended to
the history file since the beginning of the current Bash
session.
- '-r'
+ ‘-r’
Read the history file and append its contents to the history
list.
- '-w'
+ ‘-w’
Write out the current history list to the history file.
- '-p'
+ ‘-p’
Perform history substitution on the ARGs and display the
result on the standard output, without storing the results in
the history list.
- '-s'
+ ‘-s’
The ARGs are added to the end of the history list as a single
entry.
- If a FILENAME argument is supplied when any of the '-w', '-r',
- '-a', or '-n' options is used, Bash uses FILENAME as the history
- file. If not, then the value of the 'HISTFILE' variable is used.
- If 'HISTFILE' is unset or null, these options have no effect.
+ If a FILENAME argument is supplied when any of the ‘-w’, ‘-r’,
+ ‘-a’, or ‘-n’ options is used, Bash uses FILENAME as the history
+ file. If not, then the value of the ‘HISTFILE’ variable is used.
+ If ‘HISTFILE’ is unset or null, these options have no effect.
The return value is 0 unless an invalid option is encountered, an
error occurs while reading or writing the history file, an invalid
- OFFSET or range is supplied as an argument to '-d', or the history
- expansion supplied as an argument to '-p' fails.
+ OFFSET or range is supplied as an argument to ‘-d’, or the history
+ expansion supplied as an argument to ‘-p’ fails.
\1f
File: bashref.info, Node: History Interaction, Prev: Bash History Builtins, Up: Using History Interactively
=====================
The History library provides a history expansion feature that is similar
-to the history expansion provided by 'csh'. This section describes the
+to the history expansion provided by ‘csh’. This section describes the
syntax used to manipulate the history information.
History expansions introduce words from the history list into the
substitution. The second is to select portions of that line for
inclusion into the current one.
- The line selected from the history is called the "event", and the
-portions of that line that are acted upon are called "words". The line
+ The line selected from the history is called the “event”, and the
+portions of that line that are acted upon are called “words”. The line
is broken into words in the same fashion that Bash does, so that several
-words surrounded by quotes are considered one word. The "event
-designator" selects the event, the optional "word designator" selects
-words from the event, and various optional "modifiers" are available to
+words surrounded by quotes are considered one word. The “event
+designator” selects the event, the optional “word designator” selects
+words from the event, and various optional “modifiers” are available to
manipulate the selected words.
History expansions are introduced by the appearance of the history
-expansion character, which is '!' by default. History expansions may
+expansion character, which is ‘!’ by default. History expansions may
appear anywhere in the input, but do not nest.
History expansion implements shell-like quoting conventions: a
escape the history expansion character, but single quotes may not, since
they are not treated specially within double quotes.
- When using the shell, only '\' and ''' may be used to escape the
+ When using the shell, only ‘\’ and ‘'’ may be used to escape the
history expansion character, but the history expansion character is also
treated as quoted if it immediately precedes the closing double quote in
a double-quoted string.
There is a special abbreviation for substitution, active when the
-QUICK SUBSTITUTION character (default '^') is the first character on the
+QUICK SUBSTITUTION character (default ‘^’) is the first character on the
line. It selects the previous history list entry, using an event
-designator equivalent to '!!', and substitutes one string for another in
+designator equivalent to ‘!!’, and substitutes one string for another in
that line. It is described below (*note Event Designators::). This is
the only history expansion that does not begin with the history
expansion character.
- Several shell options settable with the 'shopt' builtin (*note The
+ Several shell options settable with the ‘shopt’ builtin (*note The
Shopt Builtin::) may be used to tailor the behavior of history
-expansion. If the 'histverify' shell option is enabled, and Readline is
+expansion. If the ‘histverify’ shell option is enabled, and Readline is
being used, history substitutions are not immediately passed to the
shell parser. Instead, the expanded line is reloaded into the Readline
editing buffer for further modification. If Readline is being used, and
-the 'histreedit' shell option is enabled, a failed history expansion
+the ‘histreedit’ shell option is enabled, a failed history expansion
will be reloaded into the Readline editing buffer for correction. The
-'-p' option to the 'history' builtin command may be used to see what a
-history expansion will do before using it. The '-s' option to the
-'history' builtin may be used to add commands to the end of the history
+‘-p’ option to the ‘history’ builtin command may be used to see what a
+history expansion will do before using it. The ‘-s’ option to the
+‘history’ builtin may be used to add commands to the end of the history
list without actually executing them, so that they are available for
subsequent recall. This is most useful in conjunction with Readline.
The shell allows control of the various characters used by the
-history expansion mechanism with the 'histchars' variable, as explained
+history expansion mechanism with the ‘histchars’ variable, as explained
above (*note Bash Variables::). The shell uses the history comment
character to mark history timestamps when writing the history file.
character, and ending with the word designator if one is present, or the
end of the word.
-'!'
+‘!’
Start a history substitution, except when followed by a space, tab,
- the end of the line, '=', or the rest of the shell metacharacters
+ the end of the line, ‘=’, or the rest of the shell metacharacters
defined above (*note Definitions::).
-'!N'
+‘!N’
Refer to command line N.
-'!-N'
+‘!-N’
Refer to the command N lines back.
-'!!'
- Refer to the previous command. This is a synonym for '!-1'.
+‘!!’
+ Refer to the previous command. This is a synonym for ‘!-1’.
-'!STRING'
+‘!STRING’
Refer to the most recent command preceding the current position in
the history list starting with STRING.
-'!?STRING[?]'
+‘!?STRING[?]’
Refer to the most recent command preceding the current position in
- the history list containing STRING. The trailing '?' may be
+ the history list containing STRING. The trailing ‘?’ may be
omitted if the STRING is followed immediately by a newline. If
STRING is missing, the string from the most recent search is used;
it is an error if there is no previous search string.
-'^STRING1^STRING2^'
+‘^STRING1^STRING2^’
Quick Substitution. Repeat the last command, replacing STRING1
- with STRING2. Equivalent to '!!:s^STRING1^STRING2^'.
+ with STRING2. Equivalent to ‘!!:s^STRING1^STRING2^’.
-'!#'
+‘!#’
The entire command line typed so far.
\1f
Word designators are used to select desired words from the event. They
are optional; if the word designator isn't supplied, the history
-expansion uses the entire event. A ':' separates the event
+expansion uses the entire event. A ‘:’ separates the event
specification from the word designator. It may be omitted if the word
-designator begins with a '^', '$', '*', '-', or '%'. Words are numbered
+designator begins with a ‘^’, ‘$’, ‘*’, ‘-’, or ‘%’. Words are numbered
from the beginning of the line, with the first word being denoted by 0
(zero). Words are inserted into the current line separated by single
spaces.
For example,
-'!!'
+‘!!’
designates the preceding command. When you type this, the
preceding command is repeated in toto.
-'!!:$'
+‘!!:$’
designates the last argument of the preceding command. This may be
- shortened to '!$'.
+ shortened to ‘!$’.
-'!fi:2'
+‘!fi:2’
designates the second argument of the most recent command starting
- with the letters 'fi'.
+ with the letters ‘fi’.
Here are the word designators:
-'0 (zero)'
- The '0'th word. For many applications, this is the command word.
+‘0 (zero)’
+ The ‘0’th word. For many applications, this is the command word.
-'N'
+‘N’
The Nth word.
-'^'
+‘^’
The first argument; that is, word 1.
-'$'
+‘$’
The last argument.
-'%'
- The first word matched by the most recent '?STRING?' search, if the
+‘%’
+ The first word matched by the most recent ‘?STRING?’ search, if the
search string begins with a character that is part of a word.
-'X-Y'
- A range of words; '-Y' abbreviates '0-Y'.
+‘X-Y’
+ A range of words; ‘-Y’ abbreviates ‘0-Y’.
-'*'
- All of the words, except the '0'th. This is a synonym for '1-$'.
- It is not an error to use '*' if there is just one word in the
+‘*’
+ All of the words, except the ‘0’th. This is a synonym for ‘1-$’.
+ It is not an error to use ‘*’ if there is just one word in the
event; the empty string is returned in that case.
-'X*'
- Abbreviates 'X-$'
+‘X*’
+ Abbreviates ‘X-$’
-'X-'
- Abbreviates 'X-$' like 'X*', but omits the last word. If 'x' is
+‘X-’
+ Abbreviates ‘X-$’ like ‘X*’, but omits the last word. If ‘x’ is
missing, it defaults to 0.
If a word designator is supplied without an event specification, the
---------------
After the optional word designator, you can add a sequence of one or
-more of the following modifiers, each preceded by a ':'. These modify,
+more of the following modifiers, each preceded by a ‘:’. These modify,
or edit, the word or words selected from the history event.
-'h'
+‘h’
Remove a trailing pathname component, leaving only the head.
-'t'
+‘t’
Remove all leading pathname components, leaving the tail.
-'r'
- Remove a trailing suffix of the form '.SUFFIX', leaving the
+‘r’
+ Remove a trailing suffix of the form ‘.SUFFIX’, leaving the
basename.
-'e'
+‘e’
Remove all but the trailing suffix.
-'p'
+‘p’
Print the new command but do not execute it.
-'q'
+‘q’
Quote the substituted words, escaping further substitutions.
-'x'
- Quote the substituted words as with 'q', but break into words at
- spaces, tabs, and newlines. The 'q' and 'x' modifiers are mutually
+‘x’
+ Quote the substituted words as with ‘q’, but break into words at
+ spaces, tabs, and newlines. The ‘q’ and ‘x’ modifiers are mutually
exclusive; the last one supplied is used.
-'s/OLD/NEW/'
+‘s/OLD/NEW/’
Substitute NEW for the first occurrence of OLD in the event line.
- Any character may be used as the delimiter in place of '/'. The
+ Any character may be used as the delimiter in place of ‘/’. The
delimiter may be quoted in OLD and NEW with a single backslash. If
- '&' appears in NEW, it is replaced by OLD. A single backslash will
- quote the '&'. If OLD is null, it is set to the last OLD
+ ‘&’ appears in NEW, it is replaced by OLD. A single backslash will
+ quote the ‘&’. If OLD is null, it is set to the last OLD
substituted, or, if no previous history substitutions took place,
- the last STRING in a !?STRING'[?]' search. If NEW is null, each
+ the last STRING in a !?STRING‘[?]’ search. If NEW is null, each
matching OLD is deleted. The final delimiter is optional if it is
the last character on the input line.
-'&'
+‘&’
Repeat the previous substitution.
-'g'
-'a'
+‘g’
+‘a’
Cause changes to be applied over the entire event line. Used in
- conjunction with 's', as in 'gs/OLD/NEW/', or with '&'.
+ conjunction with ‘s’, as in ‘gs/OLD/NEW/’, or with ‘&’.
-'G'
- Apply the following 's' or '&' modifier once to each word in the
+‘G’
+ Apply the following ‘s’ or ‘&’ modifier once to each word in the
event.
\1f
The simplest way to compile Bash is:
- 1. 'cd' to the directory containing the source code and type
- './configure' to configure Bash for your system. If you're using
- 'csh' on an old version of System V, you might need to type 'sh
- ./configure' instead to prevent 'csh' from trying to execute
- 'configure' itself.
+ 1. ‘cd’ to the directory containing the source code and type
+ ‘./configure’ to configure Bash for your system. If you're using
+ ‘csh’ on an old version of System V, you might need to type ‘sh
+ ./configure’ instead to prevent ‘csh’ from trying to execute
+ ‘configure’ itself.
- Running 'configure' takes some time. While running, it prints
+ Running ‘configure’ takes some time. While running, it prints
messages telling which features it is checking for.
- 2. Type 'make' to compile Bash and build the 'bashbug' bug reporting
+ 2. Type ‘make’ to compile Bash and build the ‘bashbug’ bug reporting
script.
- 3. Optionally, type 'make tests' to run the Bash test suite.
+ 3. Optionally, type ‘make tests’ to run the Bash test suite.
- 4. Type 'make install' to install 'bash' and 'bashbug'. This will
+ 4. Type ‘make install’ to install ‘bash’ and ‘bashbug’. This will
also install the manual pages and Info file, message translation
files, some supplemental documentation, a number of example
loadable builtin commands, and a set of header files for developing
loadable builtins. You may need additional privileges to install
- 'bash' to your desired destination, so 'sudo make install' might be
+ ‘bash’ to your desired destination, so ‘sudo make install’ might be
required. More information about controlling the locations where
- 'bash' and other files are installed is below (*note Installation
+ ‘bash’ and other files are installed is below (*note Installation
Names::).
- The 'configure' shell script attempts to guess correct values for
+ The ‘configure’ shell script attempts to guess correct values for
various system-dependent variables used during compilation. It uses
-those values to create a 'Makefile' in each directory of the package
-(the top directory, the 'builtins', 'doc', 'po', and 'support'
-directories, each directory under 'lib', and several others). It also
-creates a 'config.h' file containing system-dependent definitions.
-Finally, it creates a shell script named 'config.status' that you can
+those values to create a ‘Makefile’ in each directory of the package
+(the top directory, the ‘builtins’, ‘doc’, ‘po’, and ‘support’
+directories, each directory under ‘lib’, and several others). It also
+creates a ‘config.h’ file containing system-dependent definitions.
+Finally, it creates a shell script named ‘config.status’ that you can
run in the future to recreate the current configuration, a file
-'config.cache' that saves the results of its tests to speed up
-reconfiguring, and a file 'config.log' containing compiler output
-(useful mainly for debugging 'configure'). If at some point
-'config.cache' contains results you don't want to keep, you may remove
+‘config.cache’ that saves the results of its tests to speed up
+reconfiguring, and a file ‘config.log’ containing compiler output
+(useful mainly for debugging ‘configure’). If at some point
+‘config.cache’ contains results you don't want to keep, you may remove
or edit it.
- To find out more about the options and arguments that the 'configure'
+ To find out more about the options and arguments that the ‘configure’
script understands, type
bash-4.2$ ./configure --help
If you want to build Bash in a directory separate from the source
directory - to build for multiple architectures, for example - just use
the full path to the configure script. The following commands will
-build Bash in a directory under '/usr/local/build' from the source code
-in '/usr/local/src/bash-4.4':
+build Bash in a directory under ‘/usr/local/build’ from the source code
+in ‘/usr/local/src/bash-4.4’:
mkdir /usr/local/build/bash-4.4
cd /usr/local/build/bash-4.4
about building in a directory separate from the source.
If you need to do unusual things to compile Bash, please try to
-figure out how 'configure' could check whether or not to do them, and
+figure out how ‘configure’ could check whether or not to do them, and
mail diffs or instructions to <bash-maintainers@gnu.org> so they can be
considered for the next release.
- The file 'configure.ac' is used to create 'configure' by a program
-called Autoconf. You only need 'configure.ac' if you want to change it
-or regenerate 'configure' using a newer version of Autoconf. If you do
+ The file ‘configure.ac’ is used to create ‘configure’ by a program
+called Autoconf. You only need ‘configure.ac’ if you want to change it
+or regenerate ‘configure’ using a newer version of Autoconf. If you do
this, make sure you are using Autoconf version 2.69 or newer.
You can remove the program binaries and object files from the source
-code directory by typing 'make clean'. To also remove the files that
-'configure' created (so you can compile Bash for a different kind of
-computer), type 'make distclean'.
+code directory by typing ‘make clean’. To also remove the files that
+‘configure’ created (so you can compile Bash for a different kind of
+computer), type ‘make distclean’.
\1f
File: bashref.info, Node: Compilers and Options, Next: Compiling For Multiple Architectures, Prev: Basic Installation, Up: Installing Bash
==========================
Some systems require unusual options for compilation or linking that the
-'configure' script does not know about. You can give 'configure'
+‘configure’ script does not know about. You can give ‘configure’
initial values for variables by setting them in the environment. Using
a Bourne-compatible shell, you can do that on the command line like
this:
CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure
- On systems that have the 'env' program, you can do it like this:
+ On systems that have the ‘env’ program, you can do it like this:
env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure
You can compile Bash for more than one kind of computer at the same
time, by placing the object files for each architecture in their own
-directory. To do this, you must use a version of 'make' that supports
-the 'VPATH' variable, such as GNU 'make'. 'cd' to the directory where
-you want the object files and executables to go and run the 'configure'
+directory. To do this, you must use a version of ‘make’ that supports
+the ‘VPATH’ variable, such as GNU ‘make’. ‘cd’ to the directory where
+you want the object files and executables to go and run the ‘configure’
script from the source directory (*note Basic Installation::). You may
-need to supply the '--srcdir=PATH' argument to tell 'configure' where
-the source files are. 'configure' automatically checks for the source
-code in the directory that 'configure' is in and in '..'.
+need to supply the ‘--srcdir=PATH’ argument to tell ‘configure’ where
+the source files are. ‘configure’ automatically checks for the source
+code in the directory that ‘configure’ is in and in '..'.
- If you have to use a 'make' that does not support the 'VPATH'
+ If you have to use a ‘make’ that does not support the ‘VPATH’
variable, you can compile Bash for one architecture at a time in the
source code directory. After you have installed Bash for one
-architecture, use 'make distclean' before reconfiguring for another
+architecture, use ‘make distclean’ before reconfiguring for another
architecture.
Alternatively, if your system supports symbolic links, you can use
-the 'support/mkclone' script to create a build tree which has symbolic
+the ‘support/mkclone’ script to create a build tree which has symbolic
links back to each file in the source directory. Here's an example that
creates a build directory in the current directory from a source
-directory '/usr/gnu/src/bash-2.0':
+directory ‘/usr/gnu/src/bash-2.0’:
bash /usr/gnu/src/bash-2.0/support/mkclone -s /usr/gnu/src/bash-2.0 .
-The 'mkclone' script requires Bash, so you must have already built Bash
+The ‘mkclone’ script requires Bash, so you must have already built Bash
for at least one architecture before you can create build directories
for other architectures.
10.4 Installation Names
=======================
-By default, 'make install' will install into '/usr/local/bin',
-'/usr/local/man', etc.; that is, the "installation prefix" defaults to
-'/usr/local'. You can specify an installation prefix other than
-'/usr/local' by giving 'configure' the option '--prefix=PATH', or by
-specifying a value for the 'prefix' 'make' variable when running 'make
-install' (e.g., 'make install prefix=PATH'). The 'prefix' variable
-provides a default for 'exec_prefix' and other variables used when
+By default, ‘make install’ will install into ‘/usr/local/bin’,
+‘/usr/local/man’, etc.; that is, the “installation prefix” defaults to
+‘/usr/local’. You can specify an installation prefix other than
+‘/usr/local’ by giving ‘configure’ the option ‘--prefix=PATH’, or by
+specifying a value for the ‘prefix’ ‘make’ variable when running ‘make
+install’ (e.g., ‘make install prefix=PATH’). The ‘prefix’ variable
+provides a default for ‘exec_prefix’ and other variables used when
installing Bash.
You can specify separate installation prefixes for
architecture-specific files and architecture-independent files. If you
-give 'configure' the option '--exec-prefix=PATH', 'make install' will
+give ‘configure’ the option ‘--exec-prefix=PATH’, ‘make install’ will
use PATH as the prefix for installing programs and libraries.
Documentation and other data files will still use the regular prefix.
If you would like to change the installation locations for a single
-run, you can specify these variables as arguments to 'make': 'make
-install exec_prefix=/' will install 'bash' and 'bashbug' into '/bin'
-instead of the default '/usr/local/bin'.
+run, you can specify these variables as arguments to ‘make’: ‘make
+install exec_prefix=/’ will install ‘bash’ and ‘bashbug’ into ‘/bin’
+instead of the default ‘/usr/local/bin’.
If you want to see the files Bash will install and where it will
install them without changing anything on your system, specify the
-variable 'DESTDIR' as an argument to 'make'. Its value should be the
+variable ‘DESTDIR’ as an argument to ‘make’. Its value should be the
absolute directory path you'd like to use as the root of your sample
installation tree. For example,
mkdir /fs1/bash-install
make install DESTDIR=/fs1/bash-install
-will install 'bash' into '/fs1/bash-install/usr/local/bin/bash', the
+will install ‘bash’ into ‘/fs1/bash-install/usr/local/bin/bash’, the
documentation into directories within
-'/fs1/bash-install/usr/local/share', the example loadable builtins into
-'/fs1/bash-install/usr/local/lib/bash', and so on. You can use the
-usual 'exec_prefix' and 'prefix' variables to alter the directory paths
-beneath the value of 'DESTDIR'.
+‘/fs1/bash-install/usr/local/share’, the example loadable builtins into
+‘/fs1/bash-install/usr/local/lib/bash’, and so on. You can use the
+usual ‘exec_prefix’ and ‘prefix’ variables to alter the directory paths
+beneath the value of ‘DESTDIR’.
The GNU Makefile standards provide a more complete description of
these variables and their effects.
10.5 Specifying the System Type
===============================
-There may be some features 'configure' can not figure out automatically,
+There may be some features ‘configure’ can not figure out automatically,
but needs to determine by the type of host Bash will run on. Usually
-'configure' can figure that out, but if it prints a message saying it
-can not guess the host type, give it the '--host=TYPE' option. 'TYPE'
-can either be a short name for the system type, such as 'sun4', or a
-canonical name with three fields: 'CPU-COMPANY-SYSTEM' (e.g.,
-'i386-unknown-freebsd4.2').
+‘configure’ can figure that out, but if it prints a message saying it
+can not guess the host type, give it the ‘--host=TYPE’ option. ‘TYPE’
+can either be a short name for the system type, such as ‘sun4’, or a
+canonical name with three fields: ‘CPU-COMPANY-SYSTEM’ (e.g.,
+‘i386-unknown-freebsd4.2’).
- See the file 'support/config.sub' for the possible values of each
+ See the file ‘support/config.sub’ for the possible values of each
field.
\1f
10.6 Sharing Defaults
=====================
-If you want to set default values for 'configure' scripts to share, you
-can create a site shell script called 'config.site' that gives default
-values for variables like 'CC', 'cache_file', and 'prefix'. 'configure'
-looks for 'PREFIX/share/config.site' if it exists, then
-'PREFIX/etc/config.site' if it exists. Or, you can set the
-'CONFIG_SITE' environment variable to the location of the site script.
-A warning: the Bash 'configure' looks for a site script, but not all
-'configure' scripts do.
+If you want to set default values for ‘configure’ scripts to share, you
+can create a site shell script called ‘config.site’ that gives default
+values for variables like ‘CC’, ‘cache_file’, and ‘prefix’. ‘configure’
+looks for ‘PREFIX/share/config.site’ if it exists, then
+‘PREFIX/etc/config.site’ if it exists. Or, you can set the
+‘CONFIG_SITE’ environment variable to the location of the site script.
+A warning: the Bash ‘configure’ looks for a site script, but not all
+‘configure’ scripts do.
\1f
File: bashref.info, Node: Operation Controls, Next: Optional Features, Prev: Sharing Defaults, Up: Installing Bash
10.7 Operation Controls
=======================
-'configure' recognizes the following options to control how it operates.
+‘configure’ recognizes the following options to control how it operates.
-'--cache-file=FILE'
+‘--cache-file=FILE’
Use and save the results of the tests in FILE instead of
- './config.cache'. Set FILE to '/dev/null' to disable caching, for
- debugging 'configure'.
+ ‘./config.cache’. Set FILE to ‘/dev/null’ to disable caching, for
+ debugging ‘configure’.
-'--help'
- Print a summary of the options to 'configure', and exit.
+‘--help’
+ Print a summary of the options to ‘configure’, and exit.
-'--quiet'
-'--silent'
-'-q'
+‘--quiet’
+‘--silent’
+‘-q’
Do not print messages saying which checks are being made.
-'--srcdir=DIR'
+‘--srcdir=DIR’
Look for the Bash source code in directory DIR. Usually
- 'configure' can determine that directory automatically.
+ ‘configure’ can determine that directory automatically.
-'--version'
- Print the version of Autoconf used to generate the 'configure'
+‘--version’
+ Print the version of Autoconf used to generate the ‘configure’
script, and exit.
- 'configure' also accepts some other, not widely used, boilerplate
-options. 'configure --help' prints the complete list.
+ ‘configure’ also accepts some other, not widely used, boilerplate
+options. ‘configure --help’ prints the complete list.
\1f
File: bashref.info, Node: Optional Features, Prev: Operation Controls, Up: Installing Bash
10.8 Optional Features
======================
-The Bash 'configure' has a number of '--enable-FEATURE' options, where
+The Bash ‘configure’ has a number of ‘--enable-FEATURE’ options, where
FEATURE indicates an optional part of Bash. There are also several
-'--with-PACKAGE' options, where PACKAGE is something like 'bash-malloc'
-or 'purify'. To turn off the default use of a package, use
-'--without-PACKAGE'. To configure Bash without a feature that is
-enabled by default, use '--disable-FEATURE'.
+‘--with-PACKAGE’ options, where PACKAGE is something like ‘bash-malloc’
+or ‘purify’. To turn off the default use of a package, use
+‘--without-PACKAGE’. To configure Bash without a feature that is
+enabled by default, use ‘--disable-FEATURE’.
- Here is a complete list of the '--enable-' and '--with-' options that
-the Bash 'configure' recognizes.
+ Here is a complete list of the ‘--enable-’ and ‘--with-’ options that
+the Bash ‘configure’ recognizes.
-'--with-afs'
+‘--with-afs’
Define if you are using the Andrew File System from Transarc.
-'--with-bash-malloc'
- Use the Bash version of 'malloc' in the directory 'lib/malloc'.
- This is not the same 'malloc' that appears in GNU libc, but an
- older version originally derived from the 4.2 BSD 'malloc'. This
- 'malloc' is very fast, but wastes some space on each allocation.
- This option is enabled by default. The 'NOTES' file contains a
+‘--with-bash-malloc’
+ Use the Bash version of ‘malloc’ in the directory ‘lib/malloc’.
+ This is not the same ‘malloc’ that appears in GNU libc, but an
+ older version originally derived from the 4.2 BSD ‘malloc’. This
+ ‘malloc’ is very fast, but wastes some space on each allocation.
+ This option is enabled by default. The ‘NOTES’ file contains a
list of systems for which this should be turned off, and
- 'configure' disables this option automatically for a number of
+ ‘configure’ disables this option automatically for a number of
systems.
-'--with-curses'
+‘--with-curses’
Use the curses library instead of the termcap library. This should
be supplied if your system has an inadequate or incomplete termcap
database.
-'--with-gnu-malloc'
- A synonym for '--with-bash-malloc'.
+‘--with-gnu-malloc’
+ A synonym for ‘--with-bash-malloc’.
-'--with-installed-readline[=PREFIX]'
+‘--with-installed-readline[=PREFIX]’
Define this to make Bash link with a locally-installed version of
- Readline rather than the version in 'lib/readline'. This works
- only with Readline 5.0 and later versions. If PREFIX is 'yes' or
- not supplied, 'configure' uses the values of the make variables
- 'includedir' and 'libdir', which are subdirectories of 'prefix' by
+ Readline rather than the version in ‘lib/readline’. This works
+ only with Readline 5.0 and later versions. If PREFIX is ‘yes’ or
+ not supplied, ‘configure’ uses the values of the make variables
+ ‘includedir’ and ‘libdir’, which are subdirectories of ‘prefix’ by
default, to find the installed version of Readline if it is not in
the standard system include and library directories. If PREFIX is
- 'no', Bash links with the version in 'lib/readline'. If PREFIX is
- set to any other value, 'configure' treats it as a directory
+ ‘no’, Bash links with the version in ‘lib/readline’. If PREFIX is
+ set to any other value, ‘configure’ treats it as a directory
pathname and looks for the installed version of Readline in
- subdirectories of that directory (include files in PREFIX/'include'
- and the library in PREFIX/'lib').
+ subdirectories of that directory (include files in PREFIX/‘include’
+ and the library in PREFIX/‘lib’).
-'--with-libintl-prefix[=PREFIX]'
+‘--with-libintl-prefix[=PREFIX]’
Define this to make Bash link with a locally-installed version of
- the libintl library instead of the version in 'lib/intl'.
+ the libintl library instead of the version in ‘lib/intl’.
-'--with-libiconv-prefix[=PREFIX]'
+‘--with-libiconv-prefix[=PREFIX]’
Define this to make Bash look for libiconv in PREFIX instead of the
standard system locations. There is no version included with Bash.
-'--enable-minimal-config'
+‘--enable-minimal-config’
This produces a shell with minimal features, close to the
historical Bourne shell.
- There are several '--enable-' options that alter how Bash is
+ There are several ‘--enable-’ options that alter how Bash is
compiled, linked, and installed, rather than changing run-time features.
-'--enable-largefile'
+‘--enable-largefile’
Enable support for large files
(http://www.unix.org/version2/whatsnew/lfs20mar.html) if the
operating system requires special compiler options to build
programs which can access large files. This is enabled by default,
if the operating system provides large file support.
-'--enable-profiling'
+‘--enable-profiling’
This builds a Bash binary that produces profiling information to be
- processed by 'gprof' each time it is executed.
+ processed by ‘gprof’ each time it is executed.
-'--enable-separate-helpfiles'
- Use external files for the documentation displayed by the 'help'
+‘--enable-separate-helpfiles’
+ Use external files for the documentation displayed by the ‘help’
builtin instead of storing the text internally.
-'--enable-static-link'
- This causes Bash to be linked statically, if 'gcc' is being used.
+‘--enable-static-link’
+ This causes Bash to be linked statically, if ‘gcc’ is being used.
This could be used to build a version to use as root's shell.
- The 'minimal-config' option can be used to disable all of the
+ The ‘minimal-config’ option can be used to disable all of the
following options, but it is processed first, so individual options may
-be enabled using 'enable-FEATURE'.
+be enabled using ‘enable-FEATURE’.
- All of the following options except for 'alt-array-implementation',
-'disabled-builtins', 'direxpand-default', 'strict-posix-default', and
-'xpg-echo-default' are enabled by default, unless the operating system
+ All of the following options except for ‘alt-array-implementation’,
+‘disabled-builtins’, ‘direxpand-default’, ‘strict-posix-default’, and
+‘xpg-echo-default’ are enabled by default, unless the operating system
does not provide the necessary support.
-'--enable-alias'
- Allow alias expansion and include the 'alias' and 'unalias'
+‘--enable-alias’
+ Allow alias expansion and include the ‘alias’ and ‘unalias’
builtins (*note Aliases::).
-'--enable-alt-array-implementation'
+‘--enable-alt-array-implementation’
This builds Bash using an alternate implementation of arrays (*note
Arrays::) that provides faster access at the expense of using more
memory (sometimes many times more, depending on how sparse an array
is).
-'--enable-arith-for-command'
- Include support for the alternate form of the 'for' command that
- behaves like the C language 'for' statement (*note Looping
+‘--enable-arith-for-command’
+ Include support for the alternate form of the ‘for’ command that
+ behaves like the C language ‘for’ statement (*note Looping
Constructs::).
-'--enable-array-variables'
+‘--enable-array-variables’
Include support for one-dimensional array shell variables (*note
Arrays::).
-'--enable-bang-history'
- Include support for 'csh'-like history substitution (*note History
+‘--enable-bang-history’
+ Include support for ‘csh’-like history substitution (*note History
Interaction::).
-'--enable-brace-expansion'
- Include 'csh'-like brace expansion ( 'b{a,b}c' ==> 'bac bbc' ).
- See *note Brace Expansion::, for a complete description.
+‘--enable-brace-expansion’
+ Include ‘csh’-like brace expansion ( ‘b{a,b}c’ ↦ ‘bac bbc’ ). See
+ *note Brace Expansion::, for a complete description.
-'--enable-casemod-attributes'
- Include support for case-modifying attributes in the 'declare'
- builtin and assignment statements. Variables with the 'uppercase'
+‘--enable-casemod-attributes’
+ Include support for case-modifying attributes in the ‘declare’
+ builtin and assignment statements. Variables with the ‘uppercase’
attribute, for example, will have their values converted to
uppercase upon assignment.
-'--enable-casemod-expansion'
+‘--enable-casemod-expansion’
Include support for case-modifying word expansions.
-'--enable-command-timing'
- Include support for recognizing 'time' as a reserved word and for
- displaying timing statistics for the pipeline following 'time'
+‘--enable-command-timing’
+ Include support for recognizing ‘time’ as a reserved word and for
+ displaying timing statistics for the pipeline following ‘time’
(*note Pipelines::). This allows pipelines as well as shell
builtins and functions to be timed.
-'--enable-cond-command'
- Include support for the '[[' conditional command. (*note
+‘--enable-cond-command’
+ Include support for the ‘[[’ conditional command. (*note
Conditional Constructs::).
-'--enable-cond-regexp'
+‘--enable-cond-regexp’
Include support for matching POSIX regular expressions using the
- '=~' binary operator in the '[[' conditional command. (*note
+ ‘=~’ binary operator in the ‘[[’ conditional command. (*note
Conditional Constructs::).
-'--enable-coprocesses'
- Include support for coprocesses and the 'coproc' reserved word
+‘--enable-coprocesses’
+ Include support for coprocesses and the ‘coproc’ reserved word
(*note Pipelines::).
-'--enable-debugger'
+‘--enable-debugger’
Include support for the Bash debugger (distributed separately).
-'--enable-dev-fd-stat-broken'
- If calling 'stat' on /dev/fd/N returns different results than
- calling 'fstat' on file descriptor N, supply this option to enable
+‘--enable-dev-fd-stat-broken’
+ If calling ‘stat’ on /dev/fd/N returns different results than
+ calling ‘fstat’ on file descriptor N, supply this option to enable
a workaround. This has implications for conditional commands that
test file attributes.
-'--enable-direxpand-default'
- Cause the 'direxpand' shell option (*note The Shopt Builtin::) to
+‘--enable-direxpand-default’
+ Cause the ‘direxpand’ shell option (*note The Shopt Builtin::) to
be enabled by default when the shell starts. It is normally
disabled by default.
-'--enable-directory-stack'
- Include support for a 'csh'-like directory stack and the 'pushd',
- 'popd', and 'dirs' builtins (*note The Directory Stack::).
+‘--enable-directory-stack’
+ Include support for a ‘csh’-like directory stack and the ‘pushd’,
+ ‘popd’, and ‘dirs’ builtins (*note The Directory Stack::).
-'--enable-disabled-builtins'
- Allow builtin commands to be invoked via 'builtin xxx' even after
- 'xxx' has been disabled using 'enable -n xxx'. See *note Bash
- Builtins::, for details of the 'builtin' and 'enable' builtin
+‘--enable-disabled-builtins’
+ Allow builtin commands to be invoked via ‘builtin xxx’ even after
+ ‘xxx’ has been disabled using ‘enable -n xxx’. See *note Bash
+ Builtins::, for details of the ‘builtin’ and ‘enable’ builtin
commands.
-'--enable-dparen-arithmetic'
- Include support for the '((...))' command (*note Conditional
+‘--enable-dparen-arithmetic’
+ Include support for the ‘((...))’ command (*note Conditional
Constructs::).
-'--enable-extended-glob'
+‘--enable-extended-glob’
Include support for the extended pattern matching features
described above under *note Pattern Matching::.
-'--enable-extended-glob-default'
- Set the default value of the 'extglob' shell option described above
+‘--enable-extended-glob-default’
+ Set the default value of the ‘extglob’ shell option described above
under *note The Shopt Builtin:: to be enabled.
-'--enable-function-import'
+‘--enable-function-import’
Include support for importing function definitions exported by
another instance of the shell from the environment. This option is
enabled by default.
-'--enable-glob-asciiranges-default'
- Set the default value of the 'globasciiranges' shell option
+‘--enable-glob-asciiranges-default’
+ Set the default value of the ‘globasciiranges’ shell option
described above under *note The Shopt Builtin:: to be enabled.
This controls the behavior of character ranges when used in pattern
matching bracket expressions.
-'--enable-help-builtin'
- Include the 'help' builtin, which displays help on shell builtins
+‘--enable-help-builtin’
+ Include the ‘help’ builtin, which displays help on shell builtins
and variables (*note Bash Builtins::).
-'--enable-history'
- Include command history and the 'fc' and 'history' builtin commands
+‘--enable-history’
+ Include command history and the ‘fc’ and ‘history’ builtin commands
(*note Bash History Facilities::).
-'--enable-job-control'
+‘--enable-job-control’
This enables the job control features (*note Job Control::), if the
operating system supports them.
-'--enable-multibyte'
+‘--enable-multibyte’
This enables support for multibyte characters if the operating
system provides the necessary support.
-'--enable-net-redirections'
+‘--enable-net-redirections’
This enables the special handling of filenames of the form
- '/dev/tcp/HOST/PORT' and '/dev/udp/HOST/PORT' when used in
+ ‘/dev/tcp/HOST/PORT’ and ‘/dev/udp/HOST/PORT’ when used in
redirections (*note Redirections::).
-'--enable-process-substitution'
+‘--enable-process-substitution’
This enables process substitution (*note Process Substitution::) if
the operating system provides the necessary support.
-'--enable-progcomp'
+‘--enable-progcomp’
Enable the programmable completion facilities (*note Programmable
Completion::). If Readline is not enabled, this option has no
effect.
-'--enable-prompt-string-decoding'
+‘--enable-prompt-string-decoding’
Turn on the interpretation of a number of backslash-escaped
- characters in the '$PS0', '$PS1', '$PS2', and '$PS4' prompt
+ characters in the ‘$PS0’, ‘$PS1’, ‘$PS2’, and ‘$PS4’ prompt
strings. See *note Controlling the Prompt::, for a complete list
of prompt string escape sequences.
-'--enable-readline'
+‘--enable-readline’
Include support for command-line editing and history with the Bash
version of the Readline library (*note Command Line Editing::).
-'--enable-restricted'
- Include support for a "restricted shell". If this is enabled,
- Bash, when called as 'rbash', enters a restricted mode. See *note
+‘--enable-restricted’
+ Include support for a “restricted shell”. If this is enabled,
+ Bash, when called as ‘rbash’, enters a restricted mode. See *note
The Restricted Shell::, for a description of restricted mode.
-'--enable-select'
- Include the 'select' compound command, which allows the generation
+‘--enable-select’
+ Include the ‘select’ compound command, which allows the generation
of simple menus (*note Conditional Constructs::).
-'--enable-single-help-strings'
- Store the text displayed by the 'help' builtin as a single string
+‘--enable-single-help-strings’
+ Store the text displayed by the ‘help’ builtin as a single string
for each help topic. This aids in translating the text to
different languages. You may need to disable this if your compiler
cannot handle very long string literals.
-'--enable-strict-posix-default'
+‘--enable-strict-posix-default’
Make Bash POSIX-conformant by default (*note Bash POSIX Mode::).
-'--enable-translatable-strings'
- Enable support for '$"STRING"' translatable strings (*note Locale
+‘--enable-translatable-strings’
+ Enable support for ‘$"STRING"’ translatable strings (*note Locale
Translation::).
-'--enable-usg-echo-default'
- A synonym for '--enable-xpg-echo-default'.
+‘--enable-usg-echo-default’
+ A synonym for ‘--enable-xpg-echo-default’.
-'--enable-xpg-echo-default'
- Make the 'echo' builtin expand backslash-escaped characters by
- default, without requiring the '-e' option. This sets the default
- value of the 'xpg_echo' shell option to 'on', which makes the Bash
- 'echo' behave more like the version specified in the Single Unix
+‘--enable-xpg-echo-default’
+ Make the ‘echo’ builtin expand backslash-escaped characters by
+ default, without requiring the ‘-e’ option. This sets the default
+ value of the ‘xpg_echo’ shell option to ‘on’, which makes the Bash
+ ‘echo’ behave more like the version specified in the Single Unix
Specification, version 3. *Note Bash Builtins::, for a description
- of the escape sequences that 'echo' recognizes.
+ of the escape sequences that ‘echo’ recognizes.
- The file 'config-top.h' contains C Preprocessor '#define' statements
-for options which are not settable from 'configure'. Some of these are
+ The file ‘config-top.h’ contains C Preprocessor ‘#define’ statements
+for options which are not settable from ‘configure’. Some of these are
not meant to be changed; beware of the consequences if you do. Read the
comments associated with each definition for more information about its
effect.
<http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-master.tar.gz>.
Once you have determined that a bug actually exists, use the
-'bashbug' command to submit a bug report or use the form at the Bash
+‘bashbug’ command to submit a bug report or use the form at the Bash
project page (https://savannah.gnu.org/projects/bash/). If you have a
fix, you are encouraged to submit that as well! Suggestions and
'philosophical' bug reports may be mailed to <bug-bash@gnu.org> or
<help-bash@gnu.org>.
All bug reports should include:
- * The version number of Bash.
- * The hardware and operating system.
- * The compiler used to compile Bash.
- * A description of the bug behaviour.
- * A short script or 'recipe' which exercises the bug and may be used
+ • The version number of Bash.
+ • The hardware and operating system.
+ • The compiler used to compile Bash.
+ • A description of the bug behaviour.
+ • A short script or 'recipe' which exercises the bug and may be used
to reproduce it.
-'bashbug' inserts the first three items automatically into the template
+‘bashbug’ inserts the first three items automatically into the template
it provides for filing a bug report.
Please send all reports concerning this manual to <bug-bash@gnu.org>.
implemented. There are some differences between the traditional Bourne
shell and Bash; this section quickly details the differences of
significance. A number of these differences are explained in greater
-depth in previous sections. This section uses the version of 'sh'
+depth in previous sections. This section uses the version of ‘sh’
included in SVR4.2 (the last version of the historical Bourne shell) as
the baseline reference.
- * Bash is POSIX-conformant, even where the POSIX specification
- differs from traditional 'sh' behavior (*note Bash POSIX Mode::).
+ • Bash is POSIX-conformant, even where the POSIX specification
+ differs from traditional ‘sh’ behavior (*note Bash POSIX Mode::).
- * Bash has multi-character invocation options (*note Invoking
+ • Bash has multi-character invocation options (*note Invoking
Bash::).
- * Bash has command-line editing (*note Command Line Editing::) and
- the 'bind' builtin.
+ • Bash has command-line editing (*note Command Line Editing::) and
+ the ‘bind’ builtin.
- * Bash provides a programmable word completion mechanism (*note
- Programmable Completion::), and builtin commands 'complete',
- 'compgen', and 'compopt', to manipulate it.
+ • Bash provides a programmable word completion mechanism (*note
+ Programmable Completion::), and builtin commands ‘complete’,
+ ‘compgen’, and ‘compopt’, to manipulate it.
- * Bash has command history (*note Bash History Facilities::) and the
- 'history' and 'fc' builtins to manipulate it. The Bash history
+ • Bash has command history (*note Bash History Facilities::) and the
+ ‘history’ and ‘fc’ builtins to manipulate it. The Bash history
list maintains timestamp information and uses the value of the
- 'HISTTIMEFORMAT' variable to display it.
+ ‘HISTTIMEFORMAT’ variable to display it.
- * Bash implements 'csh'-like history expansion (*note History
+ • Bash implements ‘csh’-like history expansion (*note History
Interaction::).
- * Bash has one-dimensional array variables (*note Arrays::), and the
+ • Bash has one-dimensional array variables (*note Arrays::), and the
appropriate variable expansions and assignment syntax to use them.
Several of the Bash builtins take options to act on arrays. Bash
provides a number of built-in array variables.
- * The '$'...'' quoting syntax, which expands ANSI-C backslash-escaped
+ • The ‘$'...'’ quoting syntax, which expands ANSI-C backslash-escaped
characters in the text between the single quotes, is supported
(*note ANSI-C Quoting::).
- * Bash supports the '$"..."' quoting syntax to do locale-specific
- translation of the characters between the double quotes. The '-D',
- '--dump-strings', and '--dump-po-strings' invocation options list
+ • Bash supports the ‘$"..."’ quoting syntax to do locale-specific
+ translation of the characters between the double quotes. The ‘-D’,
+ ‘--dump-strings’, and ‘--dump-po-strings’ invocation options list
the translatable strings found in a script (*note Locale
Translation::).
- * Bash implements the '!' keyword to negate the return value of a
- pipeline (*note Pipelines::). Very useful when an 'if' statement
- needs to act only if a test fails. The Bash '-o pipefail' option
- to 'set' will cause a pipeline to return a failure status if any
+ • Bash implements the ‘!’ keyword to negate the return value of a
+ pipeline (*note Pipelines::). Very useful when an ‘if’ statement
+ needs to act only if a test fails. The Bash ‘-o pipefail’ option
+ to ‘set’ will cause a pipeline to return a failure status if any
command fails.
- * Bash has the 'time' reserved word and command timing (*note
+ • Bash has the ‘time’ reserved word and command timing (*note
Pipelines::). The display of the timing statistics may be
- controlled with the 'TIMEFORMAT' variable.
+ controlled with the ‘TIMEFORMAT’ variable.
- * Bash implements the 'for (( EXPR1 ; EXPR2 ; EXPR3 ))' arithmetic
+ • Bash implements the ‘for (( EXPR1 ; EXPR2 ; EXPR3 ))’ arithmetic
for command, similar to the C language (*note Looping
Constructs::).
- * Bash includes the 'select' compound command, which allows the
+ • Bash includes the ‘select’ compound command, which allows the
generation of simple menus (*note Conditional Constructs::).
- * Bash includes the '[[' compound command, which makes conditional
+ • Bash includes the ‘[[’ compound command, which makes conditional
testing part of the shell grammar (*note Conditional Constructs::),
including optional regular expression matching.
- * Bash provides optional case-insensitive matching for the 'case' and
- '[[' constructs.
+ • Bash provides optional case-insensitive matching for the ‘case’ and
+ ‘[[’ constructs.
- * Bash includes brace expansion (*note Brace Expansion::) and tilde
+ • Bash includes brace expansion (*note Brace Expansion::) and tilde
expansion (*note Tilde Expansion::).
- * Bash implements command aliases and the 'alias' and 'unalias'
+ • Bash implements command aliases and the ‘alias’ and ‘unalias’
builtins (*note Aliases::).
- * Bash provides shell arithmetic, the '((' compound command (*note
+ • Bash provides shell arithmetic, the ‘((’ compound command (*note
Conditional Constructs::), and arithmetic expansion (*note Shell
Arithmetic::).
- * Variables present in the shell's initial environment are
+ • Variables present in the shell's initial environment are
automatically exported to child processes. The Bourne shell does
not normally do this unless the variables are explicitly marked
- using the 'export' command.
+ using the ‘export’ command.
- * Bash supports the '+=' assignment operator, which appends to the
+ • Bash supports the ‘+=’ assignment operator, which appends to the
value of the variable named on the left hand side.
- * Bash includes the POSIX pattern removal '%', '#', '%%' and '##'
+ • Bash includes the POSIX pattern removal ‘%’, ‘#’, ‘%%’ and ‘##’
expansions to remove leading or trailing substrings from variable
values (*note Shell Parameter Expansion::).
- * The expansion '${#xx}', which returns the length of '${xx}', is
+ • The expansion ‘${#xx}’, which returns the length of ‘${xx}’, is
supported (*note Shell Parameter Expansion::).
- * The expansion '${var:'OFFSET'[:'LENGTH']}', which expands to the
- substring of 'var''s value of length LENGTH, beginning at OFFSET,
+ • The expansion ‘${var:’OFFSET‘[:’LENGTH‘]}’, which expands to the
+ substring of ‘var’'s value of length LENGTH, beginning at OFFSET,
is present (*note Shell Parameter Expansion::).
- * The expansion '${VAR/[/]'PATTERN'[/'REPLACEMENT']}', which matches
+ • The expansion ‘${VAR/[/]’PATTERN‘[/’REPLACEMENT‘]}’, which matches
PATTERN and replaces it with REPLACEMENT in the value of VAR, is
available (*note Shell Parameter Expansion::).
- * The expansion '${!PREFIX*}' expansion, which expands to the names
+ • The expansion ‘${!PREFIX*}’ expansion, which expands to the names
of all shell variables whose names begin with PREFIX, is available
(*note Shell Parameter Expansion::).
- * Bash has indirect variable expansion using '${!word}' (*note Shell
+ • Bash has indirect variable expansion using ‘${!word}’ (*note Shell
Parameter Expansion::).
- * Bash can expand positional parameters beyond '$9' using '${NUM}'.
+ • Bash can expand positional parameters beyond ‘$9’ using ‘${NUM}’.
- * The POSIX '$()' form of command substitution is implemented (*note
- Command Substitution::), and preferred to the Bourne shell's '``'
+ • The POSIX ‘$()’ form of command substitution is implemented (*note
+ Command Substitution::), and preferred to the Bourne shell's ‘``’
(which is also implemented for backwards compatibility).
- * Bash has process substitution (*note Process Substitution::).
+ • Bash has process substitution (*note Process Substitution::).
- * Bash automatically assigns variables that provide information about
- the current user ('UID', 'EUID', and 'GROUPS'), the current host
- ('HOSTTYPE', 'OSTYPE', 'MACHTYPE', and 'HOSTNAME'), and the
- instance of Bash that is running ('BASH', 'BASH_VERSION', and
- 'BASH_VERSINFO'). *Note Bash Variables::, for details.
+ • Bash automatically assigns variables that provide information about
+ the current user (‘UID’, ‘EUID’, and ‘GROUPS’), the current host
+ (‘HOSTTYPE’, ‘OSTYPE’, ‘MACHTYPE’, and ‘HOSTNAME’), and the
+ instance of Bash that is running (‘BASH’, ‘BASH_VERSION’, and
+ ‘BASH_VERSINFO’). *Note Bash Variables::, for details.
- * The 'IFS' variable is used to split only the results of expansion,
+ • The ‘IFS’ variable is used to split only the results of expansion,
not all words (*note Word Splitting::). This closes a longstanding
shell security hole.
- * The filename expansion bracket expression code uses '!' and '^' to
+ • The filename expansion bracket expression code uses ‘!’ and ‘^’ to
negate the set of characters between the brackets. The Bourne
- shell uses only '!'.
+ shell uses only ‘!’.
- * Bash implements the full set of POSIX filename expansion operators,
+ • Bash implements the full set of POSIX filename expansion operators,
including character classes, equivalence classes, and collating
symbols (*note Filename Expansion::).
- * Bash implements extended pattern matching features when the
- 'extglob' shell option is enabled (*note Pattern Matching::).
+ • Bash implements extended pattern matching features when the
+ ‘extglob’ shell option is enabled (*note Pattern Matching::).
- * It is possible to have a variable and a function with the same
- name; 'sh' does not separate the two name spaces.
+ • It is possible to have a variable and a function with the same
+ name; ‘sh’ does not separate the two name spaces.
- * Bash functions are permitted to have local variables using the
- 'local' builtin, and thus useful recursive functions may be written
+ • Bash functions are permitted to have local variables using the
+ ‘local’ builtin, and thus useful recursive functions may be written
(*note Bash Builtins::).
- * Variable assignments preceding commands affect only that command,
- even builtins and functions (*note Environment::). In 'sh', all
+ • Variable assignments preceding commands affect only that command,
+ even builtins and functions (*note Environment::). In ‘sh’, all
variable assignments preceding commands are global unless the
command is executed from the file system.
- * Bash performs filename expansion on filenames specified as operands
+ • Bash performs filename expansion on filenames specified as operands
to input and output redirection operators (*note Redirections::).
- * Bash contains the '<>' redirection operator, allowing a file to be
- opened for both reading and writing, and the '&>' redirection
+ • Bash contains the ‘<>’ redirection operator, allowing a file to be
+ opened for both reading and writing, and the ‘&>’ redirection
operator, for directing standard output and standard error to the
same file (*note Redirections::).
- * Bash includes the '<<<' redirection operator, allowing a string to
+ • Bash includes the ‘<<<’ redirection operator, allowing a string to
be used as the standard input to a command.
- * Bash implements the '[n]<&WORD' and '[n]>&WORD' redirection
+ • Bash implements the ‘[n]<&WORD’ and ‘[n]>&WORD’ redirection
operators, which move one file descriptor to another.
- * Bash treats a number of filenames specially when they are used in
+ • Bash treats a number of filenames specially when they are used in
redirection operators (*note Redirections::).
- * Bash can open network connections to arbitrary machines and
+ • Bash can open network connections to arbitrary machines and
services with the redirection operators (*note Redirections::).
- * The 'noclobber' option is available to avoid overwriting existing
- files with output redirection (*note The Set Builtin::). The '>|'
- redirection operator may be used to override 'noclobber'.
+ • The ‘noclobber’ option is available to avoid overwriting existing
+ files with output redirection (*note The Set Builtin::). The ‘>|’
+ redirection operator may be used to override ‘noclobber’.
- * The Bash 'cd' and 'pwd' builtins (*note Bourne Shell Builtins::)
- each take '-L' and '-P' options to switch between logical and
+ • The Bash ‘cd’ and ‘pwd’ builtins (*note Bourne Shell Builtins::)
+ each take ‘-L’ and ‘-P’ options to switch between logical and
physical modes.
- * Bash allows a function to override a builtin with the same name,
+ • Bash allows a function to override a builtin with the same name,
and provides access to that builtin's functionality within the
- function via the 'builtin' and 'command' builtins (*note Bash
+ function via the ‘builtin’ and ‘command’ builtins (*note Bash
Builtins::).
- * The 'command' builtin allows selective disabling of functions when
+ • The ‘command’ builtin allows selective disabling of functions when
command lookup is performed (*note Bash Builtins::).
- * Individual builtins may be enabled or disabled using the 'enable'
+ • Individual builtins may be enabled or disabled using the ‘enable’
builtin (*note Bash Builtins::).
- * The Bash 'exec' builtin takes additional options that allow users
+ • The Bash ‘exec’ builtin takes additional options that allow users
to control the contents of the environment passed to the executed
command, and what the zeroth argument to the command is to be
(*note Bourne Shell Builtins::).
- * Shell functions may be exported to children via the environment
- using 'export -f' (*note Shell Functions::).
+ • Shell functions may be exported to children via the environment
+ using ‘export -f’ (*note Shell Functions::).
- * The Bash 'export', 'readonly', and 'declare' builtins can take a
- '-f' option to act on shell functions, a '-p' option to display
+ • The Bash ‘export’, ‘readonly’, and ‘declare’ builtins can take a
+ ‘-f’ option to act on shell functions, a ‘-p’ option to display
variables with various attributes set in a format that can be used
- as shell input, a '-n' option to remove various variable
- attributes, and 'name=value' arguments to set variable attributes
+ as shell input, a ‘-n’ option to remove various variable
+ attributes, and ‘name=value’ arguments to set variable attributes
and values simultaneously.
- * The Bash 'hash' builtin allows a name to be associated with an
+ • The Bash ‘hash’ builtin allows a name to be associated with an
arbitrary filename, even when that filename cannot be found by
- searching the '$PATH', using 'hash -p' (*note Bourne Shell
+ searching the ‘$PATH’, using ‘hash -p’ (*note Bourne Shell
Builtins::).
- * Bash includes a 'help' builtin for quick reference to shell
+ • Bash includes a ‘help’ builtin for quick reference to shell
facilities (*note Bash Builtins::).
- * The 'printf' builtin is available to display formatted output
+ • The ‘printf’ builtin is available to display formatted output
(*note Bash Builtins::).
- * The Bash 'read' builtin (*note Bash Builtins::) will read a line
- ending in '\' with the '-r' option, and will use the 'REPLY'
+ • The Bash ‘read’ builtin (*note Bash Builtins::) will read a line
+ ending in ‘\’ with the ‘-r’ option, and will use the ‘REPLY’
variable as a default if no non-option arguments are supplied. The
- Bash 'read' builtin also accepts a prompt string with the '-p'
- option and will use Readline to obtain the line when given the '-e'
- or '-E' options. The 'read' builtin also has additional options to
- control input: the '-s' option will turn off echoing of input
- characters as they are read, the '-t' option will allow 'read' to
+ Bash ‘read’ builtin also accepts a prompt string with the ‘-p’
+ option and will use Readline to obtain the line when given the ‘-e’
+ or ‘-E’ options. The ‘read’ builtin also has additional options to
+ control input: the ‘-s’ option will turn off echoing of input
+ characters as they are read, the ‘-t’ option will allow ‘read’ to
time out if input does not arrive within a specified number of
- seconds, the '-n' option will allow reading only a specified number
- of characters rather than a full line, and the '-d' option will
+ seconds, the ‘-n’ option will allow reading only a specified number
+ of characters rather than a full line, and the ‘-d’ option will
read until a particular character rather than newline.
- * The 'return' builtin may be used to abort execution of scripts
- executed with the '.' or 'source' builtins (*note Bourne Shell
+ • The ‘return’ builtin may be used to abort execution of scripts
+ executed with the ‘.’ or ‘source’ builtins (*note Bourne Shell
Builtins::).
- * Bash includes the 'shopt' builtin, for finer control of shell
+ • Bash includes the ‘shopt’ builtin, for finer control of shell
optional capabilities (*note The Shopt Builtin::), and allows these
options to be set and unset at shell invocation (*note Invoking
Bash::).
- * Bash has much more optional behavior controllable with the 'set'
+ • Bash has much more optional behavior controllable with the ‘set’
builtin (*note The Set Builtin::).
- * The '-x' ('xtrace') option displays commands other than simple
+ • The ‘-x’ (‘xtrace’) option displays commands other than simple
commands when performing an execution trace (*note The Set
Builtin::).
- * The 'test' builtin (*note Bourne Shell Builtins::) is slightly
+ • The ‘test’ builtin (*note Bourne Shell Builtins::) is slightly
different, as it implements the POSIX algorithm, which specifies
the behavior based on the number of arguments.
- * Bash includes the 'caller' builtin, which displays the context of
+ • Bash includes the ‘caller’ builtin, which displays the context of
any active subroutine call (a shell function or a script executed
- with the '.' or 'source' builtins). This supports the Bash
+ with the ‘.’ or ‘source’ builtins). This supports the Bash
debugger.
- * The 'trap' builtin (*note Bourne Shell Builtins::) allows a 'DEBUG'
- pseudo-signal specification, similar to 'EXIT'. Commands specified
- with a 'DEBUG' trap are executed before every simple command, 'for'
- command, 'case' command, 'select' command, every arithmetic 'for'
+ • The ‘trap’ builtin (*note Bourne Shell Builtins::) allows a ‘DEBUG’
+ pseudo-signal specification, similar to ‘EXIT’. Commands specified
+ with a ‘DEBUG’ trap are executed before every simple command, ‘for’
+ command, ‘case’ command, ‘select’ command, every arithmetic ‘for’
command, and before the first command executes in a shell function.
- The 'DEBUG' trap is not inherited by shell functions unless the
- function has been given the 'trace' attribute or the 'functrace'
- option has been enabled using the 'shopt' builtin. The 'extdebug'
- shell option has additional effects on the 'DEBUG' trap.
-
- The 'trap' builtin (*note Bourne Shell Builtins::) allows an 'ERR'
- pseudo-signal specification, similar to 'EXIT' and 'DEBUG'.
- Commands specified with an 'ERR' trap are executed after a simple
- command fails, with a few exceptions. The 'ERR' trap is not
- inherited by shell functions unless the '-o errtrace' option to the
- 'set' builtin is enabled.
-
- The 'trap' builtin (*note Bourne Shell Builtins::) allows a
- 'RETURN' pseudo-signal specification, similar to 'EXIT' and
- 'DEBUG'. Commands specified with a 'RETURN' trap are executed
+ The ‘DEBUG’ trap is not inherited by shell functions unless the
+ function has been given the ‘trace’ attribute or the ‘functrace’
+ option has been enabled using the ‘shopt’ builtin. The ‘extdebug’
+ shell option has additional effects on the ‘DEBUG’ trap.
+
+ The ‘trap’ builtin (*note Bourne Shell Builtins::) allows an ‘ERR’
+ pseudo-signal specification, similar to ‘EXIT’ and ‘DEBUG’.
+ Commands specified with an ‘ERR’ trap are executed after a simple
+ command fails, with a few exceptions. The ‘ERR’ trap is not
+ inherited by shell functions unless the ‘-o errtrace’ option to the
+ ‘set’ builtin is enabled.
+
+ The ‘trap’ builtin (*note Bourne Shell Builtins::) allows a
+ ‘RETURN’ pseudo-signal specification, similar to ‘EXIT’ and
+ ‘DEBUG’. Commands specified with a ‘RETURN’ trap are executed
before execution resumes after a shell function or a shell script
- executed with '.' or 'source' returns. The 'RETURN' trap is not
+ executed with ‘.’ or ‘source’ returns. The ‘RETURN’ trap is not
inherited by shell functions unless the function has been given the
- 'trace' attribute or the 'functrace' option has been enabled using
- the 'shopt' builtin.
+ ‘trace’ attribute or the ‘functrace’ option has been enabled using
+ the ‘shopt’ builtin.
- * The Bash 'type' builtin is more extensive and gives more
+ • The Bash ‘type’ builtin is more extensive and gives more
information about the names it finds (*note Bash Builtins::).
- * The Bash 'umask' builtin permits a '-p' option to cause the output
- to be displayed in the form of a 'umask' command that may be reused
+ • The Bash ‘umask’ builtin permits a ‘-p’ option to cause the output
+ to be displayed in the form of a ‘umask’ command that may be reused
as input (*note Bourne Shell Builtins::).
- * Bash implements a 'csh'-like directory stack, and provides the
- 'pushd', 'popd', and 'dirs' builtins to manipulate it (*note The
+ • Bash implements a ‘csh’-like directory stack, and provides the
+ ‘pushd’, ‘popd’, and ‘dirs’ builtins to manipulate it (*note The
Directory Stack::). Bash also makes the directory stack visible as
- the value of the 'DIRSTACK' shell variable.
+ the value of the ‘DIRSTACK’ shell variable.
- * Bash interprets special backslash-escaped characters in the prompt
+ • Bash interprets special backslash-escaped characters in the prompt
strings when interactive (*note Controlling the Prompt::).
- * The Bash restricted mode is more useful (*note The Restricted
+ • The Bash restricted mode is more useful (*note The Restricted
Shell::); the SVR4.2 shell restricted mode is too limited.
- * The 'disown' builtin can remove a job from the internal shell job
+ • The ‘disown’ builtin can remove a job from the internal shell job
table (*note Job Control Builtins::) or suppress the sending of
- 'SIGHUP' to a job when the shell exits as the result of a 'SIGHUP'.
+ ‘SIGHUP’ to a job when the shell exits as the result of a ‘SIGHUP’.
- * Bash includes a number of features to support a separate debugger
+ • Bash includes a number of features to support a separate debugger
for shell scripts.
- * The SVR4.2 shell has two privilege-related builtins ('mldmode' and
- 'priv') not present in Bash.
+ • The SVR4.2 shell has two privilege-related builtins (‘mldmode’ and
+ ‘priv’) not present in Bash.
- * Bash does not have the 'stop' or 'newgrp' builtins.
+ • Bash does not have the ‘stop’ or ‘newgrp’ builtins.
- * Bash does not use the 'SHACCT' variable or perform shell
+ • Bash does not use the ‘SHACCT’ variable or perform shell
accounting.
- * The SVR4.2 'sh' uses a 'TIMEOUT' variable like Bash uses 'TMOUT'.
+ • The SVR4.2 ‘sh’ uses a ‘TIMEOUT’ variable like Bash uses ‘TMOUT’.
More features unique to Bash may be found in *note Bash Features::.
Since Bash is a completely new implementation, it does not suffer from
many of the limitations of the SVR4.2 shell. For instance:
- * Bash does not fork a subshell when redirecting into or out of a
- shell control structure such as an 'if' or 'while' statement.
+ • Bash does not fork a subshell when redirecting into or out of a
+ shell control structure such as an ‘if’ or ‘while’ statement.
- * Bash does not allow unbalanced quotes. The SVR4.2 shell will
- silently insert a needed closing quote at 'EOF' under certain
+ • Bash does not allow unbalanced quotes. The SVR4.2 shell will
+ silently insert a needed closing quote at ‘EOF’ under certain
circumstances. This can be the cause of some hard-to-find errors.
- * The SVR4.2 shell uses a baroque memory management scheme based on
- trapping 'SIGSEGV'. If the shell is started from a process with
- 'SIGSEGV' blocked (e.g., by using the 'system()' C library function
+ • The SVR4.2 shell uses a baroque memory management scheme based on
+ trapping ‘SIGSEGV’. If the shell is started from a process with
+ ‘SIGSEGV’ blocked (e.g., by using the ‘system()’ C library function
call), it misbehaves badly.
- * In a questionable attempt at security, the SVR4.2 shell, when
- invoked without the '-p' option, will alter its real and effective
+ • In a questionable attempt at security, the SVR4.2 shell, when
+ invoked without the ‘-p’ option, will alter its real and effective
UID and GID if they are less than some magic threshold value,
commonly 100. This can lead to unexpected results.
- * The SVR4.2 shell does not allow users to trap 'SIGSEGV', 'SIGALRM',
- or 'SIGCHLD'.
+ • The SVR4.2 shell does not allow users to trap ‘SIGSEGV’, ‘SIGALRM’,
+ or ‘SIGCHLD’.
- * The SVR4.2 shell does not allow the 'IFS', 'MAILCHECK', 'PATH',
- 'PS1', or 'PS2' variables to be unset.
+ • The SVR4.2 shell does not allow the ‘IFS’, ‘MAILCHECK’, ‘PATH’,
+ ‘PS1’, or ‘PS2’ variables to be unset.
- * The SVR4.2 shell treats '^' as the undocumented equivalent of '|'.
+ • The SVR4.2 shell treats ‘^’ as the undocumented equivalent of ‘|’.
- * Bash allows multiple option arguments when it is invoked ('-x -v');
- the SVR4.2 shell allows only one option argument ('-xv'). In fact,
+ • Bash allows multiple option arguments when it is invoked (‘-x -v’);
+ the SVR4.2 shell allows only one option argument (‘-xv’). In fact,
some versions of the shell dump core if the second argument begins
- with a '-'.
+ with a ‘-’.
- * The SVR4.2 shell exits a script if any builtin fails; Bash exits a
+ • The SVR4.2 shell exits a script if any builtin fails; Bash exits a
script only if one of the POSIX special builtins fails, and only
for certain failures, as enumerated in the POSIX standard.
- * The SVR4.2 shell behaves differently when invoked as 'jsh' (it
+ • The SVR4.2 shell behaves differently when invoked as ‘jsh’ (it
turns on job control).
\1f
Version 1.3, 3 November 2008
- Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
+ Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
<http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
- functional and useful document "free" in the sense of freedom: to
+ functional and useful document “free” in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
\0\b[index\0\b]
* Menu:
-* .: Bourne Shell Builtins.
- (line 17)
* :: Bourne Shell Builtins.
(line 11)
+* .: Bourne Shell Builtins.
+ (line 17)
* [: Bourne Shell Builtins.
(line 285)
* alias: Bash Builtins. (line 11)
* pwd: Bourne Shell Builtins.
(line 222)
* read: Bash Builtins. (line 518)
-* readarray: Bash Builtins. (line 621)
+* readarray: Bash Builtins. (line 624)
* readonly: Bourne Shell Builtins.
(line 232)
* return: Bourne Shell Builtins.
* shift: Bourne Shell Builtins.
(line 272)
* shopt: The Shopt Builtin. (line 9)
-* source: Bash Builtins. (line 630)
+* source: Bash Builtins. (line 633)
* suspend: Job Control Builtins.
(line 116)
* test: Bourne Shell Builtins.
(line 393)
* true: Bourne Shell Builtins.
(line 455)
-* type: Bash Builtins. (line 635)
-* typeset: Bash Builtins. (line 673)
-* ulimit: Bash Builtins. (line 679)
+* type: Bash Builtins. (line 638)
+* typeset: Bash Builtins. (line 676)
+* ulimit: Bash Builtins. (line 682)
* umask: Bourne Shell Builtins.
(line 460)
-* unalias: Bash Builtins. (line 785)
+* unalias: Bash Builtins. (line 788)
* unset: Bourne Shell Builtins.
(line 478)
* wait: Job Control Builtins.
* !: Pipelines. (line 9)
* [[: Conditional Constructs.
- (line 126)
+ (line 125)
* ]]: Conditional Constructs.
- (line 126)
+ (line 125)
* {: Command Grouping. (line 21)
* }: Command Grouping. (line 21)
* case: Conditional Constructs.
* in: Conditional Constructs.
(line 28)
* select: Conditional Constructs.
- (line 84)
+ (line 83)
* then: Conditional Constructs.
(line 7)
* time: Pipelines. (line 9)
\0\b[index\0\b]
* Menu:
+* _: Bash Variables. (line 13)
+* -: Special Parameters. (line 46)
* !: Special Parameters. (line 55)
+* ?: Special Parameters. (line 42)
+* @: Special Parameters. (line 22)
+* *: Special Parameters. (line 9)
* #: Special Parameters. (line 39)
* $: Special Parameters. (line 51)
+* $_: Bash Variables. (line 14)
+* $-: Special Parameters. (line 47)
* $!: Special Parameters. (line 56)
+* $?: Special Parameters. (line 43)
+* $@: Special Parameters. (line 23)
+* $*: Special Parameters. (line 10)
* $#: Special Parameters. (line 40)
* $$: Special Parameters. (line 52)
-* $*: Special Parameters. (line 10)
-* $-: Special Parameters. (line 47)
* $0: Special Parameters. (line 61)
-* $?: Special Parameters. (line 43)
-* $@: Special Parameters. (line 23)
-* $_: Bash Variables. (line 14)
-* *: Special Parameters. (line 9)
-* -: Special Parameters. (line 46)
* 0: Special Parameters. (line 60)
-* ?: Special Parameters. (line 42)
-* @: Special Parameters. (line 22)
-* _: Bash Variables. (line 13)
* active-region-end-color: Readline Init File Syntax.
(line 51)
* active-region-start-color: Readline Init File Syntax.
* auto_resume: Job Control Variables.
(line 6)
* BASH: Bash Variables. (line 23)
-* BASHOPTS: Bash Variables. (line 26)
-* BASHPID: Bash Variables. (line 35)
* BASH_ALIASES: Bash Variables. (line 42)
* BASH_ARGC: Bash Variables. (line 51)
* BASH_ARGV: Bash Variables. (line 65)
* BASH_VERSINFO: Bash Variables. (line 176)
* BASH_VERSION: Bash Variables. (line 199)
* BASH_XTRACEFD: Bash Variables. (line 202)
+* BASHOPTS: Bash Variables. (line 26)
+* BASHPID: Bash Variables. (line 35)
* bell-style: Readline Init File Syntax.
(line 64)
* bind-tty-special-chars: Readline Init File Syntax.
* COLUMNS: Bash Variables. (line 220)
* comment-begin: Readline Init File Syntax.
(line 100)
+* COMP_CWORD: Bash Variables. (line 226)
+* COMP_KEY: Bash Variables. (line 255)
+* COMP_LINE: Bash Variables. (line 232)
+* COMP_POINT: Bash Variables. (line 237)
+* COMP_TYPE: Bash Variables. (line 245)
+* COMP_WORDBREAKS: Bash Variables. (line 259)
+* COMP_WORDS: Bash Variables. (line 265)
* completion-display-width: Readline Init File Syntax.
(line 105)
* completion-ignore-case: Readline Init File Syntax.
* completion-query-items: Readline Init File Syntax.
(line 130)
* COMPREPLY: Bash Variables. (line 272)
-* COMP_CWORD: Bash Variables. (line 226)
-* COMP_KEY: Bash Variables. (line 255)
-* COMP_LINE: Bash Variables. (line 232)
-* COMP_POINT: Bash Variables. (line 237)
-* COMP_TYPE: Bash Variables. (line 245)
-* COMP_WORDBREAKS: Bash Variables. (line 259)
-* COMP_WORDS: Bash Variables. (line 265)
* convert-meta: Readline Init File Syntax.
(line 141)
* COPROC: Bash Variables. (line 278)
(line 13)
* horizontal-scroll-mode: Readline Init File Syntax.
(line 229)
-* HOSTFILE: Bash Variables. (line 493)
-* HOSTNAME: Bash Variables. (line 504)
-* HOSTTYPE: Bash Variables. (line 507)
+* HOSTFILE: Bash Variables. (line 494)
+* HOSTNAME: Bash Variables. (line 505)
+* HOSTTYPE: Bash Variables. (line 508)
* IFS: Bourne Shell Variables.
(line 18)
-* IGNOREEOF: Bash Variables. (line 510)
+* IGNOREEOF: Bash Variables. (line 511)
* input-meta: Readline Init File Syntax.
(line 238)
-* INPUTRC: Bash Variables. (line 520)
-* INSIDE_EMACS: Bash Variables. (line 524)
+* INPUTRC: Bash Variables. (line 521)
+* INSIDE_EMACS: Bash Variables. (line 525)
* isearch-terminators: Readline Init File Syntax.
(line 248)
* keymap: Readline Init File Syntax.
(line 255)
* LANG: Creating Internationalized Scripts.
(line 51)
-* LANG <1>: Bash Variables. (line 530)
-* LC_ALL: Bash Variables. (line 534)
-* LC_COLLATE: Bash Variables. (line 538)
-* LC_CTYPE: Bash Variables. (line 545)
+* LANG <1>: Bash Variables. (line 531)
+* LC_ALL: Bash Variables. (line 535)
+* LC_COLLATE: Bash Variables. (line 539)
+* LC_CTYPE: Bash Variables. (line 546)
* LC_MESSAGES: Creating Internationalized Scripts.
(line 51)
-* LC_MESSAGES <1>: Bash Variables. (line 550)
-* LC_NUMERIC: Bash Variables. (line 554)
-* LC_TIME: Bash Variables. (line 558)
-* LINENO: Bash Variables. (line 562)
-* LINES: Bash Variables. (line 567)
-* MACHTYPE: Bash Variables. (line 573)
+* LC_MESSAGES <1>: Bash Variables. (line 551)
+* LC_NUMERIC: Bash Variables. (line 555)
+* LC_TIME: Bash Variables. (line 559)
+* LINENO: Bash Variables. (line 563)
+* LINES: Bash Variables. (line 568)
+* MACHTYPE: Bash Variables. (line 574)
* MAIL: Bourne Shell Variables.
(line 22)
-* MAILCHECK: Bash Variables. (line 577)
+* MAILCHECK: Bash Variables. (line 578)
* MAILPATH: Bourne Shell Variables.
(line 27)
-* MAPFILE: Bash Variables. (line 585)
+* MAPFILE: Bash Variables. (line 586)
* mark-modified-lines: Readline Init File Syntax.
(line 285)
* mark-symlinked-directories: Readline Init File Syntax.
(line 302)
* meta-flag: Readline Init File Syntax.
(line 238)
-* OLDPWD: Bash Variables. (line 589)
+* OLDPWD: Bash Variables. (line 590)
* OPTARG: Bourne Shell Variables.
(line 34)
-* OPTERR: Bash Variables. (line 592)
+* OPTERR: Bash Variables. (line 593)
* OPTIND: Bourne Shell Variables.
(line 38)
-* OSTYPE: Bash Variables. (line 596)
+* OSTYPE: Bash Variables. (line 597)
* output-meta: Readline Init File Syntax.
(line 307)
* page-completions: Readline Init File Syntax.
(line 315)
* PATH: Bourne Shell Variables.
(line 42)
-* PIPESTATUS: Bash Variables. (line 599)
-* POSIXLY_CORRECT: Bash Variables. (line 604)
-* PPID: Bash Variables. (line 614)
-* PROMPT_COMMAND: Bash Variables. (line 618)
-* PROMPT_DIRTRIM: Bash Variables. (line 624)
-* PS0: Bash Variables. (line 630)
+* PIPESTATUS: Bash Variables. (line 600)
+* POSIXLY_CORRECT: Bash Variables. (line 605)
+* PPID: Bash Variables. (line 615)
+* PROMPT_COMMAND: Bash Variables. (line 619)
+* PROMPT_DIRTRIM: Bash Variables. (line 625)
+* PS0: Bash Variables. (line 631)
* PS1: Bourne Shell Variables.
(line 48)
* PS2: Bourne Shell Variables.
(line 53)
-* PS3: Bash Variables. (line 635)
-* PS4: Bash Variables. (line 640)
-* PWD: Bash Variables. (line 648)
-* RANDOM: Bash Variables. (line 651)
-* READLINE_ARGUMENT: Bash Variables. (line 657)
-* READLINE_LINE: Bash Variables. (line 661)
-* READLINE_MARK: Bash Variables. (line 665)
-* READLINE_POINT: Bash Variables. (line 671)
-* REPLY: Bash Variables. (line 675)
+* PS3: Bash Variables. (line 636)
+* PS4: Bash Variables. (line 641)
+* PWD: Bash Variables. (line 649)
+* RANDOM: Bash Variables. (line 652)
+* READLINE_ARGUMENT: Bash Variables. (line 658)
+* READLINE_LINE: Bash Variables. (line 662)
+* READLINE_MARK: Bash Variables. (line 666)
+* READLINE_POINT: Bash Variables. (line 672)
+* REPLY: Bash Variables. (line 676)
* revert-all-at-newline: Readline Init File Syntax.
(line 325)
* search-ignore-case: Readline Init File Syntax.
(line 332)
-* SECONDS: Bash Variables. (line 678)
-* SHELL: Bash Variables. (line 687)
-* SHELLOPTS: Bash Variables. (line 692)
-* SHLVL: Bash Variables. (line 701)
+* SECONDS: Bash Variables. (line 679)
+* SHELL: Bash Variables. (line 688)
+* SHELLOPTS: Bash Variables. (line 693)
+* SHLVL: Bash Variables. (line 702)
* show-all-if-ambiguous: Readline Init File Syntax.
(line 337)
* show-all-if-unmodified: Readline Init File Syntax.
(line 352)
* skip-completed-text: Readline Init File Syntax.
(line 358)
-* SRANDOM: Bash Variables. (line 706)
+* SRANDOM: Bash Variables. (line 707)
* TEXTDOMAIN: Creating Internationalized Scripts.
(line 51)
* TEXTDOMAINDIR: Creating Internationalized Scripts.
(line 51)
-* TIMEFORMAT: Bash Variables. (line 715)
-* TMOUT: Bash Variables. (line 753)
-* TMPDIR: Bash Variables. (line 765)
-* UID: Bash Variables. (line 769)
+* TIMEFORMAT: Bash Variables. (line 716)
+* TMOUT: Bash Variables. (line 754)
+* TMPDIR: Bash Variables. (line 766)
+* UID: Bash Variables. (line 770)
* vi-cmd-mode-string: Readline Init File Syntax.
(line 371)
* vi-ins-mode-string: Readline Init File Syntax.
* accept-line (Newline or Return): Commands For History.
(line 6)
* alias-expand-line (): Miscellaneous Commands.
- (line 132)
+ (line 133)
* backward-char (C-b): Commands For Moving. (line 15)
* backward-delete-char (Rubout): Commands For Text. (line 17)
* backward-kill-line (C-x Rubout): Commands For Killing.
* dynamic-complete-history (M-<TAB>): Commands For Completion.
(line 90)
* edit-and-execute-command (C-x C-e): Miscellaneous Commands.
- (line 141)
+ (line 142)
* end-kbd-macro (C-x )): Keyboard Macros. (line 9)
* end-of-file (usually C-d): Commands For Text. (line 6)
* end-of-history (M->): Commands For History.
* exchange-point-and-mark (C-x C-x): Miscellaneous Commands.
(line 37)
* execute-named-command (M-x): Miscellaneous Commands.
- (line 146)
+ (line 147)
* fetch-history (): Commands For History.
(line 103)
* forward-backward-delete-char (): Commands For Text. (line 21)
* glob-list-expansions (C-x g): Miscellaneous Commands.
(line 110)
* history-and-alias-expand-line (): Miscellaneous Commands.
- (line 135)
+ (line 136)
* history-expand-line (M-^): Miscellaneous Commands.
- (line 125)
+ (line 126)
* history-search-backward (): Commands For History.
(line 57)
* history-search-forward (): Commands For History.
* insert-completions (M-*): Commands For Completion.
(line 22)
* insert-last-argument (M-. or M-_): Miscellaneous Commands.
- (line 138)
+ (line 139)
* kill-line (C-k): Commands For Killing.
(line 6)
* kill-region (): Commands For Killing.
* kill-word (M-d): Commands For Killing.
(line 23)
* magic-space (): Miscellaneous Commands.
- (line 128)
+ (line 129)
* menu-complete (): Commands For Completion.
(line 26)
* menu-complete-backward (): Commands For Completion.
\1f
Tag Table:
-Node: Top\7f897
-Node: Introduction\7f2817
-Node: What is Bash?\7f3033
-Node: What is a shell?\7f4147
-Node: Definitions\7f6685
-Node: Basic Shell Features\7f9636
-Node: Shell Syntax\7f10855
-Node: Shell Operation\7f11881
-Node: Quoting\7f13174
-Node: Escape Character\7f14478
-Node: Single Quotes\7f14963
-Node: Double Quotes\7f15311
-Node: ANSI-C Quoting\7f16589
-Node: Locale Translation\7f17901
-Node: Creating Internationalized Scripts\7f19212
-Node: Comments\7f23329
-Node: Shell Commands\7f23947
-Node: Reserved Words\7f24885
-Node: Simple Commands\7f25641
-Node: Pipelines\7f26295
-Node: Lists\7f29281
-Node: Compound Commands\7f31076
-Node: Looping Constructs\7f32088
-Node: Conditional Constructs\7f34583
-Node: Command Grouping\7f49071
-Node: Coprocesses\7f50549
-Node: GNU Parallel\7f53212
-Node: Shell Functions\7f54129
-Node: Shell Parameters\7f62014
-Node: Positional Parameters\7f66402
-Node: Special Parameters\7f67304
-Node: Shell Expansions\7f70518
-Node: Brace Expansion\7f72606
-Node: Tilde Expansion\7f75340
-Node: Shell Parameter Expansion\7f77961
-Node: Command Substitution\7f96554
-Node: Arithmetic Expansion\7f100018
-Node: Process Substitution\7f100986
-Node: Word Splitting\7f102106
-Node: Filename Expansion\7f104154
-Node: Pattern Matching\7f107087
-Node: Quote Removal\7f112089
-Node: Redirections\7f112384
-Node: Executing Commands\7f122078
-Node: Simple Command Expansion\7f122748
-Node: Command Search and Execution\7f124858
-Node: Command Execution Environment\7f127245
-Node: Environment\7f130280
-Node: Exit Status\7f131943
-Node: Signals\7f133727
-Node: Shell Scripts\7f137176
-Node: Shell Builtin Commands\7f140203
-Node: Bourne Shell Builtins\7f142241
-Node: Bash Builtins\7f165633
-Node: Modifying Shell Behavior\7f198853
-Node: The Set Builtin\7f199198
-Node: The Shopt Builtin\7f210172
-Node: Special Builtins\7f226367
-Node: Shell Variables\7f227359
-Node: Bourne Shell Variables\7f227796
-Node: Bash Variables\7f229900
-Node: Bash Features\7f264969
-Node: Invoking Bash\7f265982
-Node: Bash Startup Files\7f272116
-Node: Interactive Shells\7f277247
-Node: What is an Interactive Shell?\7f277658
-Node: Is this Shell Interactive?\7f278307
-Node: Interactive Shell Behavior\7f279122
-Node: Bash Conditional Expressions\7f282751
-Node: Shell Arithmetic\7f287664
-Node: Aliases\7f290625
-Node: Arrays\7f293519
-Node: The Directory Stack\7f300153
-Node: Directory Stack Builtins\7f300937
-Node: Controlling the Prompt\7f305197
-Node: The Restricted Shell\7f308162
-Node: Bash POSIX Mode\7f310772
-Node: Shell Compatibility Mode\7f327689
-Node: Job Control\7f335940
-Node: Job Control Basics\7f336400
-Node: Job Control Builtins\7f341402
-Node: Job Control Variables\7f347197
-Node: Command Line Editing\7f348353
-Node: Introduction and Notation\7f350024
-Node: Readline Interaction\7f351647
-Node: Readline Bare Essentials\7f352838
-Node: Readline Movement Commands\7f354627
-Node: Readline Killing Commands\7f355587
-Node: Readline Arguments\7f357508
-Node: Searching\7f358552
-Node: Readline Init File\7f360738
-Node: Readline Init File Syntax\7f361999
-Node: Conditional Init Constructs\7f386024
-Node: Sample Init File\7f390220
-Node: Bindable Readline Commands\7f393344
-Node: Commands For Moving\7f394548
-Node: Commands For History\7f396599
-Node: Commands For Text\7f401593
-Node: Commands For Killing\7f405571
-Node: Numeric Arguments\7f408275
-Node: Commands For Completion\7f409414
-Node: Keyboard Macros\7f413605
-Node: Miscellaneous Commands\7f414293
-Node: Readline vi Mode\7f420662
-Node: Programmable Completion\7f421569
-Node: Programmable Completion Builtins\7f429349
-Node: A Programmable Completion Example\7f440469
-Node: Using History Interactively\7f445717
-Node: Bash History Facilities\7f446401
-Node: Bash History Builtins\7f449412
-Node: History Interaction\7f454503
-Node: Event Designators\7f458755
-Node: Word Designators\7f460293
-Node: Modifiers\7f462158
-Node: Installing Bash\7f463966
-Node: Basic Installation\7f465103
-Node: Compilers and Options\7f468825
-Node: Compiling For Multiple Architectures\7f469566
-Node: Installation Names\7f471258
-Node: Specifying the System Type\7f473367
-Node: Sharing Defaults\7f474084
-Node: Operation Controls\7f474757
-Node: Optional Features\7f475715
-Node: Reporting Bugs\7f486935
-Node: Major Differences From The Bourne Shell\7f488269
-Node: GNU Free Documentation License\7f505127
-Node: Indexes\7f530304
-Node: Builtin Index\7f530758
-Node: Reserved Word Index\7f537859
-Node: Variable Index\7f540307
-Node: Function Index\7f557441
-Node: Concept Index\7f571300
+Node: Top\7f902
+Node: Introduction\7f2844
+Node: What is Bash?\7f3060
+Node: What is a shell?\7f4204
+Node: Definitions\7f6786
+Node: Basic Shell Features\7f9965
+Node: Shell Syntax\7f11188
+Node: Shell Operation\7f12218
+Node: Quoting\7f13519
+Node: Escape Character\7f14835
+Node: Single Quotes\7f15336
+Node: Double Quotes\7f15688
+Node: ANSI-C Quoting\7f17034
+Node: Locale Translation\7f18422
+Node: Creating Internationalized Scripts\7f19769
+Node: Comments\7f23970
+Node: Shell Commands\7f24608
+Node: Reserved Words\7f25550
+Node: Simple Commands\7f26418
+Node: Pipelines\7f27080
+Node: Lists\7f30146
+Node: Compound Commands\7f32021
+Node: Looping Constructs\7f33033
+Node: Conditional Constructs\7f35580
+Node: Command Grouping\7f50487
+Node: Coprocesses\7f51977
+Node: GNU Parallel\7f54676
+Node: Shell Functions\7f55597
+Node: Shell Parameters\7f63706
+Node: Positional Parameters\7f68242
+Node: Special Parameters\7f69180
+Node: Shell Expansions\7f72490
+Node: Brace Expansion\7f74682
+Node: Tilde Expansion\7f77348
+Node: Shell Parameter Expansion\7f80117
+Node: Command Substitution\7f99144
+Node: Arithmetic Expansion\7f102680
+Node: Process Substitution\7f103648
+Node: Word Splitting\7f104788
+Node: Filename Expansion\7f106932
+Node: Pattern Matching\7f110031
+Node: Quote Removal\7f115267
+Node: Redirections\7f115574
+Node: Executing Commands\7f125386
+Node: Simple Command Expansion\7f126056
+Node: Command Search and Execution\7f128170
+Node: Command Execution Environment\7f130581
+Node: Environment\7f133893
+Node: Exit Status\7f135600
+Node: Signals\7f137388
+Node: Shell Scripts\7f141005
+Node: Shell Builtin Commands\7f144100
+Node: Bourne Shell Builtins\7f146214
+Node: Bash Builtins\7f170621
+Node: Modifying Shell Behavior\7f205229
+Node: The Set Builtin\7f205574
+Node: The Shopt Builtin\7f217092
+Node: Special Builtins\7f233831
+Node: Shell Variables\7f234823
+Node: Bourne Shell Variables\7f235260
+Node: Bash Variables\7f237456
+Node: Bash Features\7f273881
+Node: Invoking Bash\7f274898
+Node: Bash Startup Files\7f281300
+Node: Interactive Shells\7f286615
+Node: What is an Interactive Shell?\7f287026
+Node: Is this Shell Interactive?\7f287695
+Node: Interactive Shell Behavior\7f288522
+Node: Bash Conditional Expressions\7f292279
+Node: Shell Arithmetic\7f297456
+Node: Aliases\7f300541
+Node: Arrays\7f303499
+Node: The Directory Stack\7f310301
+Node: Directory Stack Builtins\7f311101
+Node: Controlling the Prompt\7f315553
+Node: The Restricted Shell\7f318694
+Node: Bash POSIX Mode\7f321484
+Node: Shell Compatibility Mode\7f338968
+Node: Job Control\7f347457
+Node: Job Control Basics\7f347917
+Node: Job Control Builtins\7f353094
+Node: Job Control Variables\7f359057
+Node: Command Line Editing\7f360237
+Node: Introduction and Notation\7f361944
+Node: Readline Interaction\7f363591
+Node: Readline Bare Essentials\7f364782
+Node: Readline Movement Commands\7f366603
+Node: Readline Killing Commands\7f367603
+Node: Readline Arguments\7f369584
+Node: Searching\7f370644
+Node: Readline Init File\7f372876
+Node: Readline Init File Syntax\7f374161
+Node: Conditional Init Constructs\7f399102
+Node: Sample Init File\7f403470
+Node: Bindable Readline Commands\7f406594
+Node: Commands For Moving\7f407822
+Node: Commands For History\7f409925
+Node: Commands For Text\7f415011
+Node: Commands For Killing\7f419089
+Node: Numeric Arguments\7f421893
+Node: Commands For Completion\7f423048
+Node: Keyboard Macros\7f427367
+Node: Miscellaneous Commands\7f428071
+Node: Readline vi Mode\7f434728
+Node: Programmable Completion\7f435683
+Node: Programmable Completion Builtins\7f443643
+Node: A Programmable Completion Example\7f455212
+Node: Using History Interactively\7f460560
+Node: Bash History Facilities\7f461244
+Node: Bash History Builtins\7f464359
+Node: History Interaction\7f469605
+Node: Event Designators\7f473933
+Node: Word Designators\7f475519
+Node: Modifiers\7f477508
+Node: Installing Bash\7f479420
+Node: Basic Installation\7f480557
+Node: Compilers and Options\7f484439
+Node: Compiling For Multiple Architectures\7f485192
+Node: Installation Names\7f486944
+Node: Specifying the System Type\7f489181
+Node: Sharing Defaults\7f489930
+Node: Operation Controls\7f490647
+Node: Optional Features\7f491669
+Node: Reporting Bugs\7f503474
+Node: Major Differences From The Bourne Shell\7f504826
+Node: GNU Free Documentation License\7f522638
+Node: Indexes\7f547818
+Node: Builtin Index\7f548272
+Node: Reserved Word Index\7f555373
+Node: Variable Index\7f557821
+Node: Function Index\7f574955
+Node: Concept Index\7f588814
\1f
End Tag Table
-This is pdfTeX, Version 3.141592653-2.6-1.40.22 (TeX Live 2021/MacPorts 2021.58693_0) (preloaded format=pdfetex 2021.8.30) 14 DEC 2023 16:39
+This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023/MacPorts 2023.66589_3) (preloaded format=pdfetex 2024.1.2) 7 FEB 2024 09:25
entering extended mode
restricted \write18 enabled.
file:line:error style messages enabled.
%&-line parsing enabled.
-**\input /usr/local/src/bash/bash-20231212/doc/bashref.texi \input /usr/local/s
-rc/bash/bash-20231212/doc/bashref.texi
-(/usr/local/src/bash/bash-20231212/doc/bashref.texi
-(/usr/local/src/bash/bash-20231212/doc/texinfo.tex
+**\input /usr/local/src/bash/bash-20240205/doc/bashref.texi \input /usr/local/s
+rc/bash/bash-20240205/doc/bashref.texi
+(/usr/local/src/bash/bash-20240205/doc/bashref.texi
+(/usr/local/src/bash/bash-20240205/doc/texinfo.tex
Loading texinfo [version 2015-11-22.14]:
\outerhsize=\dimen16
\outervsize=\dimen17
texinfo.tex: doing @include of version.texi
-(/usr/local/src/bash/bash-20231212/doc/version.texi) [1{/opt/local/var/db/texmf
+(/usr/local/src/bash/bash-20240205/doc/version.texi) [1{/opt/local/var/db/texmf
/fonts/map/pdftex/updmap/pdftex.map}] [2]
-(/usr/local/build/bash/bash-20231212/doc/bashref.toc [-1] [-2] [-3]) [-4]
-(/usr/local/build/bash/bash-20231212/doc/bashref.toc)
-(/usr/local/build/bash/bash-20231212/doc/bashref.toc) Chapter 1
+(/usr/local/build/bash/bash-20240205/doc/bashref.toc [-1] [-2] [-3]) [-4]
+(/usr/local/build/bash/bash-20240205/doc/bashref.toc)
+(/usr/local/build/bash/bash-20240205/doc/bashref.toc) Chapter 1
\openout0 = `bashref.toc'.
-(/usr/local/build/bash/bash-20231212/doc/bashref.aux)
+(/usr/local/build/bash/bash-20240205/doc/bashref.aux)
\openout1 = `bashref.aux'.
Chapter 2 [1] [2]
@rwindfile=@write4
\openout4 = `bashref.rw'.
-[9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23]
-[24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38]
-[39] [40] [41] [42] [43] [44] [45] [46] [47] Chapter 4 [48]
+[9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19{/opt/local/share/texmf-tex
+live/fonts/enc/dvips/cm-super/cm-super-t1.enc}] [20] [21] [22] [23] [24]
+[25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39]
+[40] [41] [42] [43] [44] [45] [46] [47] Chapter 4 [48]
@btindfile=@write5
\openout5 = `bashref.bt'.
- [49] [50] [51]
-[52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66]
-[67] [68]
-Overfull \hbox (38.26585pt too wide) in paragraph at lines 5420--5420
+ [49] [50] [51] [52]
+[53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67]
+[68]
+Overfull \hbox (38.26585pt too wide) in paragraph at lines 5435--5435
[]@texttt set [-abefhkmnptuvxBCEHPT] [-o @textttsl option-name@texttt ] [--] [
-] [@textttsl ar-gu-ment []@texttt ][]
.etc.
-Overfull \hbox (38.26585pt too wide) in paragraph at lines 5421--5421
+Overfull \hbox (38.26585pt too wide) in paragraph at lines 5436--5436
[]@texttt set [+abefhkmnptuvxBCEHPT] [+o @textttsl option-name@texttt ] [--] [
-] [@textttsl ar-gu-ment []@texttt ][]
[119] [120]
texinfo.tex: doing @include of rluser.texi
- (/usr/local/src/bash/bash-20231212/lib/readline/doc/rluser.texi
+ (/usr/local/src/bash/bash-20240205/lib/readline/doc/rluser.texi
Chapter 8 [121] [122] [123] [124] [125] [126] [127] [128] [129] [130] [131]
[132]
-Underfull \hbox (badness 7540) in paragraph at lines 878--884
+Underfull \hbox (badness 7540) in paragraph at lines 882--888
[]@textrm In the ex-am-ple above, @textttsl C-u[] @textrm is bound to the func
-tion
.etc.
-Underfull \hbox (badness 10000) in paragraph at lines 878--884
+Underfull \hbox (badness 10000) in paragraph at lines 882--888
@texttt universal-argument[]@textrm , @textttsl M-DEL[] @textrm is bound to th
e func-tion
.etc.
[133] [134] [135] [136]
-Overfull \hbox (26.43913pt too wide) in paragraph at lines 1112--1112
+Overfull \hbox (26.43913pt too wide) in paragraph at lines 1116--1116
[]@texttt Meta-Control-h: backward-kill-word Text after the function name is i
gnored[]
texinfo.tex: doing @include of hsuser.texi
-(/usr/local/src/bash/bash-20231212/lib/readline/doc/hsuser.texi Chapter 9
+(/usr/local/src/bash/bash-20240205/lib/readline/doc/hsuser.texi Chapter 9
[158] [159] [160] [161] [162] [163]) Chapter 10 [164] [165] [166] [167]
[168]
-Underfull \hbox (badness 10000) in paragraph at lines 9776--9785
+Underfull \hbox (badness 10000) in paragraph at lines 9801--9810
[]@textrm All of the fol-low-ing op-tions ex-cept for `@texttt alt-array-implem
entation[]@textrm '[],
.etc.
-Underfull \hbox (badness 10000) in paragraph at lines 9776--9785
+Underfull \hbox (badness 10000) in paragraph at lines 9801--9810
@textrm `@texttt disabled-builtins[]@textrm '[], `@texttt direxpand-default[]@t
extrm '[], `@texttt strict-posix-default[]@textrm '[], and
[178] [179] Appendix C [180]
texinfo.tex: doing @include of fdl.texi
- (/usr/local/src/bash/bash-20231212/doc/fdl.texi
+ (/usr/local/src/bash/bash-20240205/doc/fdl.texi
[181] [182] [183] [184] [185] [186] [187]) Appendix D [188] [189] [190]
[191] [192] [193] [194] [195] [196] [197] )
Here is how much of TeX's memory you used:
- 4104 strings out of 497086
- 47614 string characters out of 6206517
- 141909 words of memory out of 5000000
- 4869 multiletter control sequences out of 15000+600000
+ 4105 strings out of 495840
+ 47629 string characters out of 6171739
+ 143202 words of memory out of 5000000
+ 5048 multiletter control sequences out of 15000+600000
34315 words of font info for 116 fonts, out of 8000000 for 9000
- 51 hyphenation exceptions out of 8191
- 16i,6n,16p,389b,983s stack positions out of 5000i,500n,10000p,200000b,80000s
-{/opt/local/share/texmf-texlive/font
-s/enc/dvips/cm-super/cm-super-t1.enc}</opt/local/share/texmf-texlive/fonts/type
-1/public/amsfonts/cm/cmbx12.pfb></opt/local/share/texmf-texlive/fonts/type1/pub
-lic/amsfonts/cm/cmcsc10.pfb></opt/local/share/texmf-texlive/fonts/type1/public/
-amsfonts/cm/cmmi10.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfo
-nts/cm/cmmi12.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/c
-m/cmmi9.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmr1
-0.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmr9.pfb><
-/opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmsl10.pfb></opt/
-local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmsltt10.pfb></opt/loc
-al/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmsy10.pfb></opt/local/sh
-are/texmf-texlive/fonts/type1/public/amsfonts/cm/cmti10.pfb></opt/local/share/t
-exmf-texlive/fonts/type1/public/amsfonts/cm/cmtt10.pfb></opt/local/share/texmf-
-texlive/fonts/type1/public/amsfonts/cm/cmtt12.pfb></opt/local/share/texmf-texli
-ve/fonts/type1/public/amsfonts/cm/cmtt9.pfb></opt/local/share/texmf-texlive/fon
-ts/type1/public/cm-super/sfrm1095.pfb></opt/local/share/texmf-texlive/fonts/typ
-e1/public/cm-super/sfrm1440.pfb>
-Output written on bashref.pdf (203 pages, 816032 bytes).
+ 701 hyphenation exceptions out of 8191
+ 16i,6n,16p,389b,983s stack positions out of 10000i,1000n,20000p,200000b,200000s
+</opt/local/share/texmf-texlive/font
+s/type1/public/amsfonts/cm/cmbx12.pfb></opt/local/share/texmf-texlive/fonts/typ
+e1/public/amsfonts/cm/cmcsc10.pfb></opt/local/share/texmf-texlive/fonts/type1/p
+ublic/amsfonts/cm/cmmi10.pfb></opt/local/share/texmf-texlive/fonts/type1/public
+/amsfonts/cm/cmmi12.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsf
+onts/cm/cmmi9.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/c
+m/cmr10.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmr9
+.pfb></opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmsl10.pfb>
+</opt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmsltt10.pfb></o
+pt/local/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmsy10.pfb></opt/lo
+cal/share/texmf-texlive/fonts/type1/public/amsfonts/cm/cmti10.pfb></opt/local/s
+hare/texmf-texlive/fonts/type1/public/amsfonts/cm/cmtt10.pfb></opt/local/share/
+texmf-texlive/fonts/type1/public/amsfonts/cm/cmtt12.pfb></opt/local/share/texmf
+-texlive/fonts/type1/public/amsfonts/cm/cmtt9.pfb></opt/local/share/texmf-texli
+ve/fonts/type1/public/cm-super/sfrm1095.pfb></opt/local/share/texmf-texlive/fon
+ts/type1/public/cm-super/sfrm1440.pfb>
+Output written on bashref.pdf (203 pages, 816864 bytes).
PDF statistics:
2830 PDF objects out of 2984 (max. 8388607)
2580 compressed objects within 26 object streams
and @var{incr}, an optional increment, is an integer.
When integers are supplied, the expression expands to each number between
@var{x} and @var{y}, inclusive.
-Supplied integers may be prefixed with @samp{0} to force each term to have the
-same width.
When either @var{x} or @var{y} begins with a zero, the shell
attempts to force all generated terms to contain the same number of digits,
zero-padding where necessary.
using the rules listed above.
@end table
+If the shell is in @sc{posix} mode, or if the expression is part
+of the @code{[[} command,
+the @samp{<} and @samp{>} operators sort using the current locale.
If the shell is not in @sc{posix} mode,
-when used with @code{test} or @samp{[}, the @samp{<} and @samp{>}
-operators sort lexicographically using ASCII ordering.
-If the shell is in @sc{posix} mode, these operators use the current locale.
+the @code{test} and @samp{[} commands
+sort lexicographically using ASCII ordering.
The historical operator-precedence parsing with 4 or more arguments can
lead to ambiguities when it encounters strings that look like primaries.
@item HISTIGNORE
A colon-separated list of patterns used to decide which command
-lines should be saved on the history list. Each pattern is
+lines should be saved on the history list.
+Each pattern is
anchored at the beginning of the line and must match the complete
-line (no implicit @samp{*} is appended). Each pattern is tested
+line (Bash will not implicitly append a @samp{*}).
+Each pattern is tested
against the line after the checks specified by @env{HISTCONTROL}
are applied. In addition to the normal shell pattern matching
characters, @samp{&} matches the previous history line. @samp{&}
-BASH_BUILTINS(1) General Commands Manual BASH_BUILTINS(1)
-
-
+_\bB_\bA_\bS_\bH_\b__\bB_\bU_\bI_\bL_\bT_\bI_\bN_\bS(1) General Commands Manual _\bB_\bA_\bS_\bH_\b__\bB_\bU_\bI_\bL_\bT_\bI_\bN_\bS(1)
N\bNA\bAM\bME\bE
:, ., [, alias, bg, bind, break, builtin, caller, cd, command, compgen,
are not specified as accepting options interpret arguments beginning
with -\b- as invalid options and require -\b--\b- to prevent this interpreta-
tion.
+
:\b: [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
No effect; the command does nothing beyond expanding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
and performing any specified redirections. The return status is
zero.
- .\b. _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
+ .\b. _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
s\bso\bou\bur\brc\bce\be _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
Read and execute commands from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be in the current shell en-
vironment and return the exit status of the last command exe-
cuted from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be. If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not contain a slash,
filenames in P\bPA\bAT\bTH\bH are used to find the directory containing
_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, but _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not need to be executable. The file
- searched for in P\bPA\bAT\bTH\bH need not be executable. When b\bba\bas\bsh\bh is not
- in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it searches the current directory if no file is
- found in P\bPA\bAT\bTH\bH. If the s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh option to the s\bsh\bho\bop\bpt\bt builtin
- command is turned off, the P\bPA\bAT\bTH\bH is not searched. If any _\ba_\br_\bg_\bu_\b-
- _\bm_\be_\bn_\bt_\bs are supplied, they become the positional parameters when
- _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is executed. Otherwise the positional parameters are
- unchanged. If the -\b-T\bT option is enabled, .\b. inherits any trap on
+ searched for in P\bPA\bAT\bTH\bH need not be executable. When b\bba\bas\bsh\bh is not
+ in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, it searches the current directory if no file is
+ found in P\bPA\bAT\bTH\bH. If the s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh option to the s\bsh\bho\bop\bpt\bt builtin
+ command is turned off, the P\bPA\bAT\bTH\bH is not searched. If any _\ba_\br_\bg_\bu_\b-
+ _\bm_\be_\bn_\bt_\bs are supplied, they become the positional parameters when
+ _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is executed. Otherwise the positional parameters are
+ unchanged. If the -\b-T\bT option is enabled, .\b. inherits any trap on
D\bDE\bEB\bBU\bUG\bG; if it is not, any D\bDE\bEB\bBU\bUG\bG trap string is saved and restored
around the call to .\b., and .\b. unsets the D\bDE\bEB\bBU\bUG\bG trap while it exe-
cutes. If -\b-T\bT is not set, and the sourced file changes the D\bDE\bEB\bBU\bUG\bG
- trap, the new value is retained when .\b. completes. The return
- status is the status of the last command exited within the
+ trap, the new value is retained when .\b. completes. The return
+ status is the status of the last command exited within the
script (0 if no commands are executed), and false if _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is
not found or cannot be read.
a\bal\bli\bia\bas\bs [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
A\bAl\bli\bia\bas\bs with no arguments or with the -\b-p\bp option prints the list of
- aliases in the form a\bal\bli\bia\bas\bs _\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be on standard output. When
- arguments are supplied, an alias is defined for each _\bn_\ba_\bm_\be whose
- _\bv_\ba_\bl_\bu_\be is given. A trailing space in _\bv_\ba_\bl_\bu_\be causes the next word
+ aliases in the form a\bal\bli\bia\bas\bs _\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be on standard output. When
+ arguments are supplied, an alias is defined for each _\bn_\ba_\bm_\be whose
+ _\bv_\ba_\bl_\bu_\be is given. A trailing space in _\bv_\ba_\bl_\bu_\be causes the next word
to be checked for alias substitution when the alias is expanded.
For each _\bn_\ba_\bm_\be in the argument list for which no _\bv_\ba_\bl_\bu_\be is sup-
plied, the name and value of the alias is printed. A\bAl\bli\bia\bas\bs re-
b\bbg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc ...]
Resume each suspended job _\bj_\bo_\bb_\bs_\bp_\be_\bc in the background, as if it
had been started with &\b&. If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's
- notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used. b\bbg\bg _\bj_\bo_\bb_\bs_\bp_\be_\bc returns 0 unless
- run when job control is disabled or, when run with job control
- enabled, any specified _\bj_\bo_\bb_\bs_\bp_\be_\bc was not found or was started
+ notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used. b\bbg\bg _\bj_\bo_\bb_\bs_\bp_\be_\bc returns 0 unless
+ run when job control is disabled or, when run with job control
+ enabled, any specified _\bj_\bo_\bb_\bs_\bp_\be_\bc was not found or was started
without job control.
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] [-\b-l\blp\bps\bsv\bvP\bPS\bSV\bVX\bX]
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] _\bk_\be_\by_\bs_\be_\bq:_\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] _\bk_\be_\by_\bs_\be_\bq:_\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
b\bbi\bin\bnd\bd _\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b-_\bl_\bi_\bn_\be
- Display current r\bre\bea\bad\bdl\bli\bin\bne\be key and function bindings, bind a key
- sequence to a r\bre\bea\bad\bdl\bli\bin\bne\be function or macro, or set a r\bre\bea\bad\bdl\bli\bin\bne\be
+ Display current r\bre\bea\bad\bdl\bli\bin\bne\be key and function bindings, bind a key
+ sequence to a r\bre\bea\bad\bdl\bli\bin\bne\be function or macro, or set a r\bre\bea\bad\bdl\bli\bin\bne\be
variable. Each non-option argument is a command as it would ap-
pear in a r\bre\bea\bad\bdl\bli\bin\bne\be initialization file such as _\b._\bi_\bn_\bp_\bu_\bt_\br_\bc, but
each binding or command must be passed as a separate argument;
_\bm_\ba_\bn_\bd is executed, the shell sets the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_L\bLI\bIN\bNE\bE vari-
able to the contents of the r\bre\bea\bad\bdl\bli\bin\bne\be line buffer and the
R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT and R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_M\bMA\bAR\bRK\bK variables to the current
- location of the insertion point and the saved insertion
- point (the mark), respectively. The shell assigns any
- numeric argument the user supplied to the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_A\bAR\bRG\bGU\bU-\b-
- M\bME\bEN\bNT\bT variable. If there was no argument, that variable
+ location of the insertion point and the saved insertion
+ point (the mark), respectively. The shell assigns any
+ numeric argument the user supplied to the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_A\bAR\bRG\bGU\bU-\b-
+ M\bME\bEN\bNT\bT variable. If there was no argument, that variable
is not set. If the executed command changes the value of
any of R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_L\bLI\bIN\bNE\bE, R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT, or R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_M\bMA\bAR\bRK\bK,
those new values will be reflected in the editing state.
associated commands in a format that can be reused as in-
put.
- The return value is 0 unless an unrecognized option is given or
+ The return value is 0 unless an unrecognized option is given or
an error occurred.
b\bbr\bre\bea\bak\bk [_\bn]
- Exit from within a f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or s\bse\bel\ble\bec\bct\bt loop. If _\bn is
- specified, break _\bn levels. _\bn must be >= 1. If _\bn is greater
- than the number of enclosing loops, all enclosing loops are ex-
- ited. The return value is 0 unless _\bn is not greater than or
+ Exit from within a f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or s\bse\bel\ble\bec\bct\bt loop. If _\bn is
+ specified, break _\bn levels. _\bn must be >= 1. If _\bn is greater
+ than the number of enclosing loops, all enclosing loops are ex-
+ ited. The return value is 0 unless _\bn is not greater than or
equal to 1.
b\bbu\bui\bil\blt\bti\bin\bn _\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
- Execute the specified shell builtin, passing it _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs, and
+ Execute the specified shell builtin, passing it _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs, and
return its exit status. This is useful when defining a function
whose name is the same as a shell builtin, retaining the func-
tionality of the builtin within the function. The c\bcd\bd builtin is
- commonly redefined this way. The return status is false if
+ commonly redefined this way. The return status is false if
_\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn is not a shell builtin command.
c\bca\bal\bll\ble\ber\br [_\be_\bx_\bp_\br]
out _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number and source filename of
the current subroutine call. If a non-negative integer is sup-
plied as _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number, subroutine name,
- and source file corresponding to that position in the current
- execution call stack. This extra information may be used, for
- example, to print a stack trace. The current frame is frame 0.
- The return value is 0 unless the shell is not executing a sub-
- routine call or _\be_\bx_\bp_\br does not correspond to a valid position in
+ and source file corresponding to that position in the current
+ execution call stack. This extra information may be used, for
+ example, to print a stack trace. The current frame is frame 0.
+ The return value is 0 unless the shell is not executing a sub-
+ routine call or _\be_\bx_\bp_\br does not correspond to a valid position in
the call stack.
c\bcd\bd [-\b-L\bL|[-\b-P\bP [-\b-e\be]]] [-@] [_\bd_\bi_\br]
- Change the current directory to _\bd_\bi_\br. if _\bd_\bi_\br is not supplied,
- the value of the H\bHO\bOM\bME\bE shell variable is the default. The vari-
+ Change the current directory to _\bd_\bi_\br. if _\bd_\bi_\br is not supplied,
+ the value of the H\bHO\bOM\bME\bE shell variable is the default. The vari-
able C\bCD\bDP\bPA\bAT\bTH\bH defines the search path for the directory containing
- _\bd_\bi_\br: each directory name in C\bCD\bDP\bPA\bAT\bTH\bH is searched for _\bd_\bi_\br. Alter-
- native directory names in C\bCD\bDP\bPA\bAT\bTH\bH are separated by a colon (:).
- A null directory name in C\bCD\bDP\bPA\bAT\bTH\bH is the same as the current di-
- rectory, i.e., ``.\b.''. If _\bd_\bi_\br begins with a slash (/), then C\bCD\bD-\b-
- P\bPA\bAT\bTH\bH is not used. The -\b-P\bP option causes c\bcd\bd to use the physical
- directory structure by resolving symbolic links while traversing
- _\bd_\bi_\br and before processing instances of _\b._\b. in _\bd_\bi_\br (see also the
- -\b-P\bP option to the s\bse\bet\bt builtin command); the -\b-L\bL option forces sym-
- bolic links to be followed by resolving the link after process-
- ing instances of _\b._\b. in _\bd_\bi_\br. If _\b._\b. appears in _\bd_\bi_\br, it is pro-
- cessed by removing the immediately previous pathname component
- from _\bd_\bi_\br, back to a slash or the beginning of _\bd_\bi_\br. If the -\b-e\be
- option is supplied with -\b-P\bP, and the current working directory
- cannot be successfully determined after a successful directory
- change, c\bcd\bd will return an unsuccessful status. On systems that
- support it, the -\b-@\b@ option presents the extended attributes asso-
- ciated with a file as a directory. An argument of -\b- is con-
- verted to $\b$O\bOL\bLD\bDP\bPW\bWD\bD before the directory change is attempted. If
- a non-empty directory name from C\bCD\bDP\bPA\bAT\bTH\bH is used, or if -\b- is the
- first argument, and the directory change is successful, the ab-
- solute pathname of the new working directory is written to the
- standard output. If the directory change is successful, c\bcd\bd sets
- the value of the P\bPW\bWD\bD environment variable to the new directory
- name, and sets the O\bOL\bLD\bDP\bPW\bWD\bD environment variable to the value of
- the current working directory before the change. The return
- value is true if the directory was successfully changed; false
- otherwise.
+ _\bd_\bi_\br: the shell searches each directory name in C\bCD\bDP\bPA\bAT\bTH\bH for _\bd_\bi_\br.
+ Alternative directory names in C\bCD\bDP\bPA\bAT\bTH\bH are separated by a colon
+ (:). A null directory name in C\bCD\bDP\bPA\bAT\bTH\bH is the same as the current
+ directory, i.e., If _\bd_\bi_\br begins with a slash (/), then C\bCD\bDP\bPA\bAT\bTH\bH is
+ not used. The -\b-P\bP option causes c\bcd\bd to use the physical directory
+ structure by resolving symbolic links while traversing _\bd_\bi_\br and
+ before processing instances of _\b._\b. in _\bd_\bi_\br (see also the -\b-P\bP option
+ to the s\bse\bet\bt builtin command); the -\b-L\bL option forces symbolic links
+ to be followed by resolving the link after processing instances
+ of _\b._\b. in _\bd_\bi_\br. If _\b._\b. appears in _\bd_\bi_\br, it is processed by removing
+ the immediately previous pathname component from _\bd_\bi_\br, back to a
+ slash or the beginning of _\bd_\bi_\br. If the -\b-e\be option is supplied
+ with -\b-P\bP, and the current working directory cannot be success-
+ fully determined after a successful directory change, c\bcd\bd will
+ return an unsuccessful status. On systems that support it, the
+ -\b-@\b@ option presents the extended attributes associated with a
+ file as a directory. An argument of -\b- is converted to $\b$O\bOL\bLD\bDP\bPW\bWD\bD
+ before the directory change is attempted. If a non-empty direc-
+ tory name from C\bCD\bDP\bPA\bAT\bTH\bH is used, or if -\b- is the first argument,
+ and the directory change is successful, the absolute pathname of
+ the new working directory is written to the standard output. If
+ the directory change is successful, c\bcd\bd sets the value of the P\bPW\bWD\bD
+ environment variable to the new directory name, and sets the
+ O\bOL\bLD\bDP\bPW\bWD\bD environment variable to the value of the current working
+ directory before the change. The return value is true if the
+ directory was successfully changed; false otherwise.
c\bco\bom\bmm\bma\ban\bnd\bd [-\b-p\bpV\bVv\bv] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\ba_\br_\bg ...]
Run _\bc_\bo_\bm_\bm_\ba_\bn_\bd with _\ba_\br_\bg_\bs suppressing the normal shell function
lookup. Only builtin commands or commands found in the P\bPA\bAT\bTH\bH are
- executed. If the -\b-p\bp option is given, the search for _\bc_\bo_\bm_\bm_\ba_\bn_\bd is
- performed using a default value for P\bPA\bAT\bTH\bH that is guaranteed to
- find all of the standard utilities. If either the -\b-V\bV or -\b-v\bv op-
- tion is supplied, a description of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is printed. The -\b-v\bv
- option causes a single word indicating the command or filename
+ executed. If the -\b-p\bp option is given, the search for _\bc_\bo_\bm_\bm_\ba_\bn_\bd is
+ performed using a default value for P\bPA\bAT\bTH\bH that is guaranteed to
+ find all of the standard utilities. If either the -\b-V\bV or -\b-v\bv op-
+ tion is supplied, a description of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is printed. The -\b-v\bv
+ option causes a single word indicating the command or filename
used to invoke _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be displayed; the -\b-V\bV option produces a
more verbose description. If the -\b-V\bV or -\b-v\bv option is supplied,
the exit status is 0 if _\bc_\bo_\bm_\bm_\ba_\bn_\bd was found, and 1 if not. If
neither option is supplied and an error occurred or _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
- not be found, the exit status is 127. Otherwise, the exit sta-
+ not be found, the exit status is 127. Otherwise, the exit sta-
tus of the c\bco\bom\bmm\bma\ban\bnd\bd builtin is the exit status of _\bc_\bo_\bm_\bm_\ba_\bn_\bd.
c\bco\bom\bmp\bpg\bge\ben\bn [-\b-V\bV _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bw_\bo_\br_\bd]
- Generate possible completion matches for _\bw_\bo_\br_\bd according to the
- _\bo_\bp_\bt_\bi_\bo_\bns, which may be any option accepted by the c\bco\bom\bmp\bpl\ble\bet\bte\be
+ Generate possible completion matches for _\bw_\bo_\br_\bd according to the
+ _\bo_\bp_\bt_\bi_\bo_\bns, which may be any option accepted by the c\bco\bom\bmp\bpl\ble\bet\bte\be
builtin with the exceptions of -\b-p\bp, -\b-r\br, -\b-D\bD, -\b-E\bE, and -\b-I\bI, and write
the matches to the standard output. If the -\b-V\bV option is sup-
plied, c\bco\bom\bmp\bpg\bge\ben\bn stores the generated completions into the indexed
- array variable _\bv_\ba_\br_\bn_\ba_\bm_\be instead of writing them to the standard
- output. When using the -\b-F\bF or -\b-C\bC options, the various shell
- variables set by the programmable completion facilities, while
+ array variable _\bv_\ba_\br_\bn_\ba_\bm_\be instead of writing them to the standard
+ output. When using the -\b-F\bF or -\b-C\bC options, the various shell
+ variables set by the programmable completion facilities, while
available, will not have useful values.
The matches will be generated in the same way as if the program-
mable completion code had generated them directly from a comple-
- tion specification with the same flags. If _\bw_\bo_\br_\bd is specified,
+ tion specification with the same flags. If _\bw_\bo_\br_\bd is specified,
only those completions matching _\bw_\bo_\br_\bd will be displayed.
- The return value is true unless an invalid option is supplied,
+ The return value is true unless an invalid option is supplied,
or no matches were generated.
c\bco\bom\bmp\bpl\ble\bet\bte\be [-\b-a\bab\bbc\bcd\bde\bef\bfg\bgj\bjk\bks\bsu\buv\bv] [-\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bEI\bI] [-\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn]
[-\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt] [-\b-W\bW _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt] [-\b-F\bF _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn] [-\b-C\bC _\bc_\bo_\bm_\bm_\ba_\bn_\bd]
- [-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt] [-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx] [-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be _\b._\b._\b.]
+ [-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt] [-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx] [-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
c\bco\bom\bmp\bpl\ble\bet\bte\be -\b-p\bpr\br [-\b-D\bDE\bEI\bI] [_\bn_\ba_\bm_\be ...]
- Specify how arguments to each _\bn_\ba_\bm_\be should be completed. If the
- -\b-p\bp option is supplied, or if no options are supplied, existing
- completion specifications are printed in a way that allows them
- to be reused as input. The -\b-r\br option removes a completion spec-
- ification for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are supplied, all com-
- pletion specifications. The -\b-D\bD option indicates that other sup-
- plied options and actions should apply to the ``default'' com-
- mand completion; that is, completion attempted on a command for
- which no completion has previously been defined. The -\b-E\bE option
- indicates that other supplied options and actions should apply
- to ``empty'' command completion; that is, completion attempted
- on a blank line. The -\b-I\bI option indicates that other supplied
- options and actions should apply to completion on the initial
- non-assignment word on the line, or after a command delimiter
- such as ;\b; or |\b|, which is usually command name completion. If
- multiple options are supplied, the -\b-D\bD option takes precedence
- over -\b-E\bE, and both take precedence over -\b-I\bI. If any of -\b-D\bD, -\b-E\bE, or
- -\b-I\bI are supplied, any other _\bn_\ba_\bm_\be arguments are ignored; these
- completions only apply to the case specified by the option.
-
- The process of applying these completion specifications when
- word completion is attempted is described in _\bb_\ba_\bs_\bh_\b(_\b1_\b).
-
- Other options, if specified, have the following meanings. The
- arguments to the -\b-G\bG, -\b-W\bW, and -\b-X\bX options (and, if necessary, the
- -\b-P\bP and -\b-S\bS options) should be quoted to protect them from expan-
+ Specify how arguments to each _\bn_\ba_\bm_\be should be completed. If the
+ -\b-p\bp option is supplied, or if no options or _\bn_\ba_\bm_\bes are supplied,
+ existing completion specifications are printed in a way that al-
+ lows them to be reused as input. The -\b-r\br option removes a com-
+ pletion specification for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are sup-
+ plied, all completion specifications. The -\b-D\bD option indicates
+ that other supplied options and actions should apply to the com-
+ mand completion; that is, completion attempted on a command for
+ which no completion has previously been defined. The -\b-E\bE option
+ indicates that other supplied options and actions should apply
+ to command completion; that is, completion attempted on a blank
+ line. The -\b-I\bI option indicates that other supplied options and
+ actions should apply to completion on the initial non-assignment
+ word on the line, or after a command delimiter such as ;\b; or |\b|,
+ which is usually command name completion. If multiple options
+ are supplied, the -\b-D\bD option takes precedence over -\b-E\bE, and both
+ take precedence over -\b-I\bI. If any of -\b-D\bD, -\b-E\bE, or -\b-I\bI are supplied,
+ any other _\bn_\ba_\bm_\be arguments are ignored; these completions only ap-
+ ply to the case specified by the option.
+
+ The process of applying these completion specifications when
+ word completion is attempted is described in _\bb_\ba_\bs_\bh(1).
+
+ Other options, if specified, have the following meanings. The
+ arguments to the -\b-G\bG, -\b-W\bW, and -\b-X\bX options (and, if necessary, the
+ -\b-P\bP and -\b-S\bS options) should be quoted to protect them from expan-
sion before the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin is invoked.
-\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn
- The _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn controls several aspects of the comp-
- spec's behavior beyond the simple generation of comple-
+ The _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn controls several aspects of the comp-
+ spec's behavior beyond the simple generation of comple-
tions. _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn may be one of:
b\bba\bas\bsh\bhd\bde\bef\bfa\bau\bul\blt\bt
Perform the rest of the default b\bba\bas\bsh\bh completions
tempted and any matches are added to the results
of the other actions.
-\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn
- The _\ba_\bc_\bt_\bi_\bo_\bn may be one of the following to generate a
+ The _\ba_\bc_\bt_\bi_\bo_\bn may be one of the following to generate a
list of possible completions:
a\bal\bli\bia\bas\bs Alias names. May also be specified as -\b-a\ba.
a\bar\brr\bra\bay\byv\bva\bar\br
Array variable names.
b\bbi\bin\bnd\bdi\bin\bng\bg R\bRe\bea\bad\bdl\bli\bin\bne\be key binding names.
- b\bbu\bui\bil\blt\bti\bin\bn Names of shell builtin commands. May also be
+ b\bbu\bui\bil\blt\bti\bin\bn Names of shell builtin commands. May also be
specified as -\b-b\bb.
c\bco\bom\bmm\bma\ban\bnd\bd Command names. May also be specified as -\b-c\bc.
d\bdi\bir\bre\bec\bct\bto\bor\bry\by
d\bdi\bis\bsa\bab\bbl\ble\bed\bd
Names of disabled shell builtins.
e\ben\bna\bab\bbl\ble\bed\bd Names of enabled shell builtins.
- e\bex\bxp\bpo\bor\brt\bt Names of exported shell variables. May also be
+ e\bex\bxp\bpo\bor\brt\bt Names of exported shell variables. May also be
specified as -\b-e\be.
f\bfi\bil\ble\be File names. May also be specified as -\b-f\bf.
f\bfu\bun\bnc\bct\bti\bio\bon\bn
h\bhe\bel\blp\bpt\bto\bop\bpi\bic\bc
Help topics as accepted by the h\bhe\bel\blp\bp builtin.
h\bho\bos\bst\btn\bna\bam\bme\be
- Hostnames, as taken from the file specified by
+ Hostnames, as taken from the file specified by
the H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE shell variable.
- j\bjo\bob\bb Job names, if job control is active. May also
+ j\bjo\bob\bb Job names, if job control is active. May also
be specified as -\b-j\bj.
- k\bke\bey\byw\bwo\bor\brd\bd Shell reserved words. May also be specified as
+ k\bke\bey\byw\bwo\bor\brd\bd Shell reserved words. May also be specified as
-\b-k\bk.
r\bru\bun\bnn\bni\bin\bng\bg Names of running jobs, if job control is active.
s\bse\ber\brv\bvi\bic\bce\be Service names. May also be specified as -\b-s\bs.
- s\bse\bet\bto\bop\bpt\bt Valid arguments for the -\b-o\bo option to the s\bse\bet\bt
+ s\bse\bet\bto\bop\bpt\bt Valid arguments for the -\b-o\bo option to the s\bse\bet\bt
builtin.
- s\bsh\bho\bop\bpt\bt Shell option names as accepted by the s\bsh\bho\bop\bpt\bt
+ s\bsh\bho\bop\bpt\bt Shell option names as accepted by the s\bsh\bho\bop\bpt\bt
builtin.
s\bsi\big\bgn\bna\bal\bl Signal names.
s\bst\bto\bop\bpp\bpe\bed\bd Names of stopped jobs, if job control is active.
first argument ($\b$1\b1) is the name of the command whose ar-
guments are being completed, the second argument ($\b$2\b2) is
the word being completed, and the third argument ($\b$3\b3) is
- the word preceding the word being completed on the cur-
- rent command line. When it finishes, the possible com-
- pletions are retrieved from the value of the C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY
+ the word preceding the word being completed on the cur-
+ rent command line. When it finishes, the possible com-
+ pletions are retrieved from the value of the C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY
array variable.
-\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt
- The pathname expansion pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
+ The pathname expansion pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
generate the possible completions.
-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx
- _\bp_\br_\be_\bf_\bi_\bx is added at the beginning of each possible com-
+ _\bp_\br_\be_\bf_\bi_\bx is added at the beginning of each possible com-
pletion after all other options have been applied.
-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx
_\bs_\bu_\bf_\bf_\bi_\bx is appended to each possible completion after all
special variable as delimiters, and each resultant word
is expanded. Shell quoting is honored within _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt,
in order to provide a mechanism for the words to contain
- shell metacharacters or characters in the value of I\bIF\bFS\bS.
- The possible completions are the members of the resul-
+ shell metacharacters or characters in the value of I\bIF\bFS\bS.
+ The possible completions are the members of the resul-
tant list which match the word being completed.
-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt
- _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for pathname expansion.
+ _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for pathname expansion.
It is applied to the list of possible completions gener-
ated by the preceding options and arguments, and each
completion matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed from the list.
The return value is true unless an invalid option is supplied,
an option other than -\b-p\bp, -\b-r\br, -\b-D\bD, -\b-E\bE, or -\b-I\bI is supplied without a
- _\bn_\ba_\bm_\be argument, an attempt is made to remove a completion speci-
+ _\bn_\ba_\bm_\be argument, an attempt is made to remove a completion speci-
fication for a _\bn_\ba_\bm_\be for which no specification exists, or an er-
ror occurs adding a completion specification.
c\bco\bom\bmp\bpo\bop\bpt\bt [-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bEI\bI] [+\b+o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be]
Modify completion options for each _\bn_\ba_\bm_\be according to the _\bo_\bp_\b-
_\bt_\bi_\bo_\bns, or for the currently-executing completion if no _\bn_\ba_\bm_\bes are
- supplied. If no _\bo_\bp_\bt_\bi_\bo_\bns are given, display the completion op-
- tions for each _\bn_\ba_\bm_\be or the current completion. The possible
- values of _\bo_\bp_\bt_\bi_\bo_\bn are those valid for the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin de-
- scribed above. The -\b-D\bD option indicates that other supplied op-
- tions should apply to the ``default'' command completion; that
- is, completion attempted on a command for which no completion
- has previously been defined. The -\b-E\bE option indicates that other
- supplied options should apply to ``empty'' command completion;
- that is, completion attempted on a blank line. The -\b-I\bI option
- indicates that other supplied options should apply to completion
- on the initial non-assignment word on the line, or after a com-
- mand delimiter such as ;\b; or |\b|, which is usually command name
- completion.
+ supplied. If no _\bo_\bp_\bt_\bi_\bo_\bns are given, display the completion op-
+ tions for each _\bn_\ba_\bm_\be or the current completion. The possible
+ values of _\bo_\bp_\bt_\bi_\bo_\bn are those valid for the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin de-
+ scribed above. The -\b-D\bD option indicates that other supplied op-
+ tions should apply to the command completion; that is, comple-
+ tion attempted on a command for which no completion has previ-
+ ously been defined. The -\b-E\bE option indicates that other supplied
+ options should apply to command completion; that is, completion
+ attempted on a blank line. The -\b-I\bI option indicates that other
+ supplied options should apply to completion on the initial non-
+ assignment word on the line, or after a command delimiter such
+ as ;\b; or |\b|, which is usually command name completion.
- The return value is true unless an invalid option is supplied,
+ The return value is true unless an invalid option is supplied,
an attempt is made to modify the options for a _\bn_\ba_\bm_\be for which no
completion specification exists, or an output error occurs.
c\bco\bon\bnt\bti\bin\bnu\bue\be [_\bn]
Resume the next iteration of the enclosing f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or
- s\bse\bel\ble\bec\bct\bt loop. If _\bn is specified, resume at the _\bnth enclosing
- loop. _\bn must be >= 1. If _\bn is greater than the number of en-
- closing loops, the last enclosing loop (the ``top-level'' loop)
- is resumed. The return value is 0 unless _\bn is not greater than
- or equal to 1.
+ s\bse\bel\ble\bec\bct\bt loop. If _\bn is specified, resume at the _\bnth enclosing
+ loop. _\bn must be >= 1. If _\bn is greater than the number of en-
+ closing loops, the shell resumes the last enclosing loop (the
+ loop). The return value is 0 unless _\bn is not greater than or
+ equal to 1.
d\bde\bec\bcl\bla\bar\bre\be [-\b-a\baA\bAf\bfF\bFg\bgi\biI\bIl\bln\bnr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
t\bty\byp\bpe\bes\bse\bet\bt [-\b-a\baA\bAf\bfF\bFg\bgi\biI\bIl\bln\bnr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
- Declare variables and/or give them attributes. If no _\bn_\ba_\bm_\bes are
- given then display the values of variables. The -\b-p\bp option will
+ Declare variables and/or give them attributes. If no _\bn_\ba_\bm_\bes are
+ given then display the values of variables. The -\b-p\bp option will
display the attributes and values of each _\bn_\ba_\bm_\be. When -\b-p\bp is used
with _\bn_\ba_\bm_\be arguments, additional options, other than -\b-f\bf and -\b-F\bF,
are ignored. When -\b-p\bp is supplied without _\bn_\ba_\bm_\be arguments, it
will display the attributes and values of all variables having
the attributes specified by the additional options. If no other
- options are supplied with -\b-p\bp, d\bde\bec\bcl\bla\bar\bre\be will display the at-
- tributes and values of all shell variables. The -\b-f\bf option will
- restrict the display to shell functions. The -\b-F\bF option inhibits
- the display of function definitions; only the function name and
+ options are supplied with -\b-p\bp, d\bde\bec\bcl\bla\bar\bre\be will display the attrib-
+ utes and values of all shell variables. The -\b-f\bf option will re-
+ strict the display to shell functions. The -\b-F\bF option inhibits
+ the display of function definitions; only the function name and
attributes are printed. If the e\bex\bxt\btd\bde\beb\bbu\bug\bg shell option is enabled
using s\bsh\bho\bop\bpt\bt, the source file name and line number where each
_\bn_\ba_\bm_\be is defined are displayed as well. The -\b-F\bF option implies
tion. It is ignored in all other cases. The -\b-I\bI option causes
local variables to inherit the attributes (except the _\bn_\ba_\bm_\be_\br_\be_\bf
attribute) and value of any existing variable with the same _\bn_\ba_\bm_\be
- at a surrounding scope. If there is no existing variable, the
+ at a surrounding scope. If there is no existing variable, the
local variable is initially unset. The following options can be
- used to restrict output to variables with the specified attri-
- bute or to give variables attributes:
+ used to restrict output to variables with the specified at-
+ tribute or to give variables attributes:
-\b-a\ba Each _\bn_\ba_\bm_\be is an indexed array variable (see A\bAr\brr\bra\bay\bys\bs in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
+ _\bb_\ba_\bs_\bh(1)).
-\b-A\bA Each _\bn_\ba_\bm_\be is an associative array variable (see A\bAr\brr\bra\bay\bys\bs in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
+ _\bb_\ba_\bs_\bh(1)).
-\b-f\bf Use function names only.
-\b-i\bi The variable is treated as an integer; arithmetic evalua-
- tion (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) is performed
+ tion (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh(1)) is performed
when the variable is assigned a value.
-\b-l\bl When the variable is assigned a value, all upper-case
characters are converted to lower-case. The upper-case
-\b-x\bx Mark _\bn_\ba_\bm_\bes for export to subsequent commands via the en-
vironment.
- Using `+' instead of `-' turns off the attribute instead, with
- the exceptions that +\b+a\ba and +\b+A\bA may not be used to destroy array
- variables and +\b+r\br will not remove the readonly attribute. When
- used in a function, d\bde\bec\bcl\bla\bar\bre\be and t\bty\byp\bpe\bes\bse\bet\bt make each _\bn_\ba_\bm_\be local, as
- with the l\blo\boc\bca\bal\bl command, unless the -\b-g\bg option is supplied. If a
- variable name is followed by =_\bv_\ba_\bl_\bu_\be, the value of the variable
- is set to _\bv_\ba_\bl_\bu_\be. When using -\b-a\ba or -\b-A\bA and the compound assign-
- ment syntax to create array variables, additional attributes do
- not take effect until subsequent assignments. The return value
- is 0 unless an invalid option is encountered, an attempt is made
- to define a function using ``-f foo=bar'', an attempt is made to
- assign a value to a readonly variable, an attempt is made to as-
- sign a value to an array variable without using the compound as-
- signment syntax (see A\bAr\brr\bra\bay\bys\bs in _\bb_\ba_\bs_\bh_\b(_\b1_\b)), one of the _\bn_\ba_\bm_\be_\bs is not
- a valid shell variable name, an attempt is made to turn off
- readonly status for a readonly variable, an attempt is made to
- turn off array status for an array variable, or an attempt is
- made to display a non-existent function with -\b-f\bf.
+ Using instead of turns off the attribute instead, with the ex-
+ ceptions that +\b+a\ba and +\b+A\bA may not be used to destroy array vari-
+ ables and +\b+r\br will not remove the readonly attribute. When used
+ in a function, d\bde\bec\bcl\bla\bar\bre\be and t\bty\byp\bpe\bes\bse\bet\bt make each _\bn_\ba_\bm_\be local, as with
+ the l\blo\boc\bca\bal\bl command, unless the -\b-g\bg option is supplied. If a vari-
+ able name is followed by =_\bv_\ba_\bl_\bu_\be, the value of the variable is
+ set to _\bv_\ba_\bl_\bu_\be. When using -\b-a\ba or -\b-A\bA and the compound assignment
+ syntax to create array variables, additional attributes do not
+ take effect until subsequent assignments. The return value is 0
+ unless an invalid option is encountered, an attempt is made to
+ define a function using an attempt is made to assign a value to
+ a readonly variable, an attempt is made to assign a value to an
+ array variable without using the compound assignment syntax (see
+ A\bAr\brr\bra\bay\bys\bs in _\bb_\ba_\bs_\bh(1)), one of the _\bn_\ba_\bm_\be_\bs is not a valid shell vari-
+ able name, an attempt is made to turn off readonly status for a
+ readonly variable, an attempt is made to turn off array status
+ for an array variable, or an attempt is made to display a non-
+ existent function with -\b-f\bf.
d\bdi\bir\brs\bs [\b[-\b-c\bcl\blp\bpv\bv]\b] [\b[+\b+_\bn]\b] [\b[-\b-_\bn]\b]
Without options, displays the list of currently remembered di-
list with the p\bpu\bus\bsh\bhd\bd command; the p\bpo\bop\bpd\bd command removes entries
from the list. The current directory is always the first direc-
tory in the stack.
- -\b-c\bc Clears the directory stack by deleting all of the en-
+ -\b-c\bc Clears the directory stack by deleting all of the en-
tries.
- -\b-l\bl Produces a listing using full pathnames; the default
+ -\b-l\bl Produces a listing using full pathnames; the default
listing format uses a tilde to denote the home directory.
-\b-p\bp Print the directory stack with one entry per line.
- -\b-v\bv Print the directory stack with one entry per line, pre-
+ -\b-v\bv Print the directory stack with one entry per line, pre-
fixing each entry with its index in the stack.
+\b+_\bn Displays the _\bnth entry counting from the left of the list
shown by d\bdi\bir\brs\bs when invoked without options, starting with
zero.
- -\b-_\bn Displays the _\bnth entry counting from the right of the
+ -\b-_\bn Displays the _\bnth entry counting from the right of the
list shown by d\bdi\bir\brs\bs when invoked without options, starting
with zero.
is given, each _\bj_\bo_\bb_\bs_\bp_\be_\bc is not removed from the table, but is
marked so that S\bSI\bIG\bGH\bHU\bUP\bP is not sent to the job if the shell re-
ceives a S\bSI\bIG\bGH\bHU\bUP\bP. If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is supplied, the -\b-a\ba option means
- to remove or mark all jobs; the -\b-r\br option without a _\bj_\bo_\bb_\bs_\bp_\be_\bc ar-
+ to remove or mark all jobs; the -\b-r\br option without a _\bj_\bo_\bb_\bs_\bp_\be_\bc ar-
gument restricts operation to running jobs. The return value is
0 unless a _\bj_\bo_\bb_\bs_\bp_\be_\bc does not specify a valid job.
Output the _\ba_\br_\bgs, separated by spaces, followed by a newline.
The return status is 0 unless a write error occurs. If -\b-n\bn is
specified, the trailing newline is suppressed. If the -\b-e\be option
- is given, interpretation of the following backslash-escaped
- characters is enabled. The -\b-E\bE option disables the interpreta-
- tion of these escape characters, even on systems where they are
- interpreted by default. The x\bxp\bpg\bg_\b_e\bec\bch\bho\bo shell option may be used
- to dynamically determine whether or not e\bec\bch\bho\bo interprets any op-
+ is given, interpretation of the following backslash-escaped
+ characters is enabled. The -\b-E\bE option disables the interpreta-
+ tion of these escape characters, even on systems where they are
+ interpreted by default. The x\bxp\bpg\bg_\b_e\bec\bch\bho\bo shell option may be used
+ to dynamically determine whether or not e\bec\bch\bho\bo interprets any op-
tions and expands these escape characters by default. e\bec\bch\bho\bo does
not interpret -\b--\b- to mean the end of options. e\bec\bch\bho\bo interprets
the following escape sequences:
e\ben\bna\bab\bbl\ble\be [-\b-a\ba] [-\b-d\bdn\bnp\bps\bs] [-\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be] [_\bn_\ba_\bm_\be ...]
Enable and disable builtin shell commands. Disabling a builtin
allows a disk command which has the same name as a shell builtin
- to be executed without specifying a full pathname, even though
- the shell normally searches for builtins before disk commands.
- If -\b-n\bn is used, each _\bn_\ba_\bm_\be is disabled; otherwise, _\bn_\ba_\bm_\be_\bs are en-
- abled. For example, to use the t\bte\bes\bst\bt binary found via the P\bPA\bAT\bTH\bH
- instead of the shell builtin version, run ``enable -n test''.
- The -\b-f\bf option means to load the new builtin command _\bn_\ba_\bm_\be from
- shared object _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, on systems that support dynamic loading.
- B\bBa\bas\bsh\bh will use the value of the B\bBA\bAS\bSH\bH_\b_L\bLO\bOA\bAD\bDA\bAB\bBL\bLE\bES\bS_\b_P\bPA\bAT\bTH\bH variable as a
- colon-separated list of directories in which to search for _\bf_\bi_\bl_\be_\b-
- _\bn_\ba_\bm_\be, if _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not contain a slash. The default is sys-
- tem-dependent, and may include "." to force a search of the cur-
- rent directory. The -\b-d\bd option will delete a builtin previously
- loaded with -\b-f\bf. If no _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp
- option is supplied, a list of shell builtins is printed. With
- no other option arguments, the list consists of all enabled
- shell builtins. If -\b-n\bn is supplied, only disabled builtins are
- printed. If -\b-a\ba is supplied, the list printed includes all
- builtins, with an indication of whether or not each is enabled.
- If -\b-s\bs is supplied, the output is restricted to the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl
- builtins. If no options are supplied and a _\bn_\ba_\bm_\be is not a shell
- builtin, e\ben\bna\bab\bbl\ble\be will attempt to load _\bn_\ba_\bm_\be from a shared object
- named _\bn_\ba_\bm_\be, as if the command were ``enable -f _\bn_\ba_\bm_\be _\bn_\ba_\bm_\be . The
- return value is 0 unless a _\bn_\ba_\bm_\be is not a shell builtin or there
- is an error loading a new builtin from a shared object.
+ to be executed without specifying a full pathname, even though
+ the shell normally searches for builtins before disk commands.
+ If -\b-n\bn is used, each _\bn_\ba_\bm_\be is disabled; otherwise, _\bn_\ba_\bm_\be_\bs are en-
+ abled. For example, to use the t\bte\bes\bst\bt binary found via the P\bPA\bAT\bTH\bH
+ instead of the shell builtin version, run The -\b-f\bf option means to
+ load the new builtin command _\bn_\ba_\bm_\be from shared object _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be,
+ on systems that support dynamic loading. B\bBa\bas\bsh\bh will use the
+ value of the B\bBA\bAS\bSH\bH_\b_L\bLO\bOA\bAD\bDA\bAB\bBL\bLE\bES\bS_\b_P\bPA\bAT\bTH\bH variable as a colon-separated
+ list of directories in which to search for _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, if _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
+ does not contain a slash. The default is system-dependent, and
+ may include to force a search of the current directory. The -\b-d\bd
+ option will delete a builtin previously loaded with -\b-f\bf. If no
+ _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
+ list of shell builtins is printed. With no other option argu-
+ ments, the list consists of all enabled shell builtins. If -\b-n\bn
+ is supplied, only disabled builtins are printed. If -\b-a\ba is sup-
+ plied, the list printed includes all builtins, with an indica-
+ tion of whether or not each is enabled. If -\b-s\bs is supplied, the
+ output is restricted to the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl builtins. If no op-
+ tions are supplied and a _\bn_\ba_\bm_\be is not a shell builtin, e\ben\bna\bab\bbl\ble\be
+ will attempt to load _\bn_\ba_\bm_\be from a shared object named _\bn_\ba_\bm_\be, as if
+ the command were The return value is 0 unless a _\bn_\ba_\bm_\be is not a
+ shell builtin or there is an error loading a new builtin from a
+ shared object.
e\bev\bva\bal\bl [_\ba_\br_\bg ...]
The _\ba_\br_\bgs are read and concatenated together into a single com-
_\bg_\bi_\bn(1) does. The -\b-c\bc option causes _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed with
an empty environment. If -\b-a\ba is supplied, the shell passes _\bn_\ba_\bm_\be
as the zeroth argument to the executed command. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
- not be executed for some reason, a non-interactive shell exits,
- unless the e\bex\bxe\bec\bcf\bfa\bai\bil\bl shell option is enabled. In that case, it
- returns failure. An interactive shell returns failure if the
- file cannot be executed. A subshell exits unconditionally if
- e\bex\bxe\bec\bc fails. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is not specified, any redirections take
- effect in the current shell, and the return status is 0. If
+ not be executed for some reason, a non-interactive shell exits,
+ unless the e\bex\bxe\bec\bcf\bfa\bai\bil\bl shell option is enabled. In that case, it
+ returns failure. An interactive shell returns failure if the
+ file cannot be executed. A subshell exits unconditionally if
+ e\bex\bxe\bec\bc fails. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is not specified, any redirections take
+ effect in the current shell, and the return status is 0. If
there is a redirection error, the return status is 1.
e\bex\bxi\bit\bt [_\bn]
- Cause the shell to exit with a status of _\bn. If _\bn is omitted,
+ Cause the shell to exit with a status of _\bn. If _\bn is omitted,
the exit status is that of the last command executed. A trap on
E\bEX\bXI\bIT\bT is executed before the shell terminates.
to be removed from each _\bn_\ba_\bm_\be. If a variable name is followed by
=_\bw_\bo_\br_\bd, the value of the variable is set to _\bw_\bo_\br_\bd. e\bex\bxp\bpo\bor\brt\bt returns
an exit status of 0 unless an invalid option is encountered, one
- of the _\bn_\ba_\bm_\be_\bs is not a valid shell variable name, or -\b-f\bf is sup-
+ of the _\bn_\ba_\bm_\be_\bs is not a valid shell variable name, or -\b-f\bf is sup-
plied with a _\bn_\ba_\bm_\be that is not a function.
f\bfa\bal\bls\bse\be Does nothing, returns a non-zero status.
f\bfc\bc [-\b-e\be _\be_\bn_\ba_\bm_\be] [-\b-l\bln\bnr\br] [_\bf_\bi_\br_\bs_\bt] [_\bl_\ba_\bs_\bt]
f\bfc\bc -\b-s\bs [_\bp_\ba_\bt=_\br_\be_\bp] [_\bc_\bm_\bd]
- The first form selects a range of commands from _\bf_\bi_\br_\bs_\bt to _\bl_\ba_\bs_\bt
- from the history list and displays or edits and re-executes
- them. _\bF_\bi_\br_\bs_\bt and _\bl_\ba_\bs_\bt may be specified as a string (to locate
- the last command beginning with that string) or as a number (an
- index into the history list, where a negative number is used as
- an offset from the current command number). When listing, a
- _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt of 0 is equivalent to -1 and -0 is equivalent to
- the current command (usually the f\bfc\bc command); otherwise 0 is
- equivalent to -1 and -0 is invalid. If _\bl_\ba_\bs_\bt is not specified,
- it is set to the current command for listing (so that ``fc -l
- -10'' prints the last 10 commands) and to _\bf_\bi_\br_\bs_\bt otherwise. If
- _\bf_\bi_\br_\bs_\bt is not specified, it is set to the previous command for
- editing and -16 for listing.
+ The first form selects a range of commands from _\bf_\bi_\br_\bs_\bt to _\bl_\ba_\bs_\bt
+ from the history list and displays or edits and re-executes
+ them. _\bF_\bi_\br_\bs_\bt and _\bl_\ba_\bs_\bt may be specified as a string (to locate
+ the last command beginning with that string) or as a number (an
+ index into the history list, where a negative number is used as
+ an offset from the current command number). When listing, a
+ _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt of 0 is equivalent to -1 and -0 is equivalent to
+ the current command (usually the f\bfc\bc command); otherwise 0 is
+ equivalent to -1 and -0 is invalid. If _\bl_\ba_\bs_\bt is not specified,
+ it is set to the current command for listing (so that prints the
+ last 10 commands) and to _\bf_\bi_\br_\bs_\bt otherwise. If _\bf_\bi_\br_\bs_\bt is not spec-
+ ified, it is set to the previous command for editing and -16 for
+ listing.
The -\b-n\bn option suppresses the command numbers when listing. The
-\b-r\br option reverses the order of the commands. If the -\b-l\bl option
In the second form, _\bc_\bo_\bm_\bm_\ba_\bn_\bd is re-executed after each instance
of _\bp_\ba_\bt is replaced by _\br_\be_\bp. _\bC_\bo_\bm_\bm_\ba_\bn_\bd is interpreted the same as
- _\bf_\bi_\br_\bs_\bt above. A useful alias to use with this is ``r="fc -s"'',
- so that typing ``r cc'' runs the last command beginning with
- ``cc'' and typing ``r'' re-executes the last command.
+ _\bf_\bi_\br_\bs_\bt above. A useful alias to use with this is so that typing
+ runs the last command beginning with and typing re-executes the
+ last command.
If the first form is used, the return value is 0 unless an in-
valid option is encountered or _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt specify history
f\bfg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc]
Resume _\bj_\bo_\bb_\bs_\bp_\be_\bc in the foreground, and make it the current job.
If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb
- is used. The return value is that of the command placed into
- the foreground, or failure if run when job control is disabled
+ is used. The return value is that of the command placed into
+ the foreground, or failure if run when job control is disabled
or, when run with job control enabled, if _\bj_\bo_\bb_\bs_\bp_\be_\bc does not spec-
ify a valid job or _\bj_\bo_\bb_\bs_\bp_\be_\bc specifies a job that was started
without job control.
- g\bge\bet\bto\bop\bpt\bts\bs _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg _\bn_\ba_\bm_\be [_\ba_\br_\bg _\b._\b._\b.]
+ g\bge\bet\bto\bop\bpt\bts\bs _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg _\bn_\ba_\bm_\be [_\ba_\br_\bg ...]
g\bge\bet\bto\bop\bpt\bts\bs is used by shell procedures to parse positional parame-
ters. _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg contains the option characters to be recog-
nized; if a character is followed by a colon, the option is ex-
pected to have an argument, which should be separated from it by
- white space. The colon and question mark characters may not be
- used as option characters. Each time it is invoked, g\bge\bet\bto\bop\bpt\bts\bs
- places the next option in the shell variable _\bn_\ba_\bm_\be, initializing
+ white space. The colon and question mark characters may not be
+ used as option characters. Each time it is invoked, g\bge\bet\bto\bop\bpt\bts\bs
+ places the next option in the shell variable _\bn_\ba_\bm_\be, initializing
_\bn_\ba_\bm_\be if it does not exist, and the index of the next argument to
be processed into the variable O\bOP\bPT\bTI\bIN\bND\bD. O\bOP\bPT\bTI\bIN\bND\bD is initialized to
1 each time the shell or a shell script is invoked. When an op-
variable O\bOP\bPT\bTE\bER\bRR\bR is set to 0, no error messages will be dis-
played, even if the first character of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is not a colon.
- If an invalid option is seen, g\bge\bet\bto\bop\bpt\bts\bs places ? into _\bn_\ba_\bm_\be and, if
- not silent, prints an error message and unsets O\bOP\bPT\bTA\bAR\bRG\bG. If
- g\bge\bet\bto\bop\bpt\bts\bs is silent, the option character found is placed in O\bOP\bP-\b-
- T\bTA\bAR\bRG\bG and no diagnostic message is printed.
+ If g\bge\bet\bto\bop\bpt\bts\bs detects an invalid option, it places ? into _\bn_\ba_\bm_\be and,
+ if not silent, prints an error message and unsets O\bOP\bPT\bTA\bAR\bRG\bG. If
+ g\bge\bet\bto\bop\bpt\bts\bs is silent, it assigns the option character found to O\bOP\bP-\b-
+ T\bTA\bAR\bRG\bG and does not print a diagnostic message.
- If a required argument is not found, and g\bge\bet\bto\bop\bpt\bts\bs is not silent,
- a question mark (?\b?) is placed in _\bn_\ba_\bm_\be, O\bOP\bPT\bTA\bAR\bRG\bG is unset, and a
- diagnostic message is printed. If g\bge\bet\bto\bop\bpt\bts\bs is silent, then a
- colon (:\b:) is placed in _\bn_\ba_\bm_\be and O\bOP\bPT\bTA\bAR\bRG\bG is set to the option
+ If a required argument is not found, and g\bge\bet\bto\bop\bpt\bts\bs is not silent,
+ it sets the value of _\bn_\ba_\bm_\be to a question mark (?\b?), unsets O\bOP\bPT\bTA\bAR\bRG\bG,
+ and prints a diagnostic message. If g\bge\bet\bto\bop\bpt\bts\bs is silent, it sets
+ the value of _\bn_\ba_\bm_\be to a colon (:\b:) and sets O\bOP\bPT\bTA\bAR\bRG\bG to the option
character found.
g\bge\bet\bto\bop\bpt\bts\bs returns true if an option, specified or unspecified, is
Each time h\bha\bas\bsh\bh is invoked, the full pathname of the command _\bn_\ba_\bm_\be
is determined by searching the directories in $\b$P\bPA\bAT\bTH\bH and remem-
bered. Any previously-remembered pathname is discarded. If the
- -\b-p\bp option is supplied, h\bha\bas\bsh\bh uses _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be as the full filename
- of the command. The -\b-r\br option causes the shell to forget all
- remembered locations. Assigning to the P\bPA\bAT\bTH\bH variable also
- clears all hashed filenames. The -\b-d\bd option causes the shell to
- forget the remembered location of each _\bn_\ba_\bm_\be. If the -\b-t\bt option
+ -\b-p\bp option is supplied, h\bha\bas\bsh\bh uses _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be as the full filename
+ of the command. The -\b-r\br option causes the shell to forget all
+ remembered locations. Assigning to the P\bPA\bAT\bTH\bH variable also
+ clears all hashed filenames. The -\b-d\bd option causes the shell to
+ forget the remembered location of each _\bn_\ba_\bm_\be. If the -\b-t\bt option
is supplied, the full pathname to which each _\bn_\ba_\bm_\be corresponds is
printed. If multiple _\bn_\ba_\bm_\be arguments are supplied with -\b-t\bt, the
_\bn_\ba_\bm_\be is printed before the hashed full pathname. The -\b-l\bl option
and -\b-p\bp options (the options that act on the _\bn_\ba_\bm_\be arguments) are
mutually exclusive. Only one will be active. If more than one
is supplied, -\b-t\bt has higher priority than -\b-p\bp, and both are higher
- priority than -\b-d\bd. The return status is true unless a _\bn_\ba_\bm_\be is
+ priority than -\b-d\bd. The return status is true unless a _\bn_\ba_\bm_\be is
not found or an invalid option is supplied.
h\bhe\bel\blp\bp [-\b-d\bdm\bms\bs] [_\bp_\ba_\bt_\bt_\be_\br_\bn]
- Display helpful information about builtin commands. If _\bp_\ba_\bt_\bt_\be_\br_\bn
- is specified, h\bhe\bel\blp\bp gives detailed help on all commands matching
- _\bp_\ba_\bt_\bt_\be_\br_\bn; otherwise help for all the builtins and shell control
+ Display helpful information about builtin commands. If _\bp_\ba_\bt_\bt_\be_\br_\bn
+ is specified, h\bhe\bel\blp\bp gives detailed help on all commands matching
+ _\bp_\ba_\bt_\bt_\be_\br_\bn; otherwise help for all the builtins and shell control
structures is printed.
-\b-d\bd Display a short description of each _\bp_\ba_\bt_\bt_\be_\br_\bn
-\b-m\bm Display the description of each _\bp_\ba_\bt_\bt_\be_\br_\bn in a manpage-like
h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bs_\bt_\ba_\br_\bt-_\be_\bn_\bd
h\bhi\bis\bst\bto\bor\bry\by -\b-a\ban\bnr\brw\bw [_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be]
- h\bhi\bis\bst\bto\bor\bry\by -\b-p\bp _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
- h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
+ h\bhi\bis\bst\bto\bor\bry\by -\b-p\bp _\ba_\br_\bg [_\ba_\br_\bg ...]
+ h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg ...]
With no options, display the command history list with line num-
bers. Lines listed with a *\b* have been modified. An argument of
_\bn lists only the last _\bn lines. If the shell variable H\bHI\bIS\bST\bTT\bTI\bIM\bME\bE-\b-
Delete the range of history entries between positions
_\bs_\bt_\ba_\br_\bt and _\be_\bn_\bd, inclusive. Positive and negative values
for _\bs_\bt_\ba_\br_\bt and _\be_\bn_\bd are interpreted as described above.
- -\b-a\ba Append the ``new'' history lines to the history file.
- These are history lines entered since the beginning of
- the current b\bba\bas\bsh\bh session, but not already appended to the
- history file.
+ -\b-a\ba Append the history lines to the history file. These are
+ history lines entered since the beginning of the current
+ b\bba\bas\bsh\bh session, but not already appended to the history
+ file.
-\b-n\bn Read the history lines not already read from the history
file into the current history list. These are lines ap-
pended to the history file since the beginning of the
the current history list.
-\b-w\bw Write the current history list to the history file, over-
writing the history file's contents.
- -\b-p\bp Perform history substitution on the following _\ba_\br_\bg_\bs and
- display the result on the standard output. Does not
- store the results in the history list. Each _\ba_\br_\bg must be
+ -\b-p\bp Perform history substitution on the following _\ba_\br_\bg_\bs and
+ display the result on the standard output. Does not
+ store the results in the history list. Each _\ba_\br_\bg must be
quoted to disable normal history expansion.
- -\b-s\bs Store the _\ba_\br_\bg_\bs in the history list as a single entry.
- The last command in the history list is removed before
+ -\b-s\bs Store the _\ba_\br_\bg_\bs in the history list as a single entry.
+ The last command in the history list is removed before
the _\ba_\br_\bg_\bs are added.
- If the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable is set, the time stamp informa-
- tion associated with each history entry is written to the his-
- tory file, marked with the history comment character. When the
- history file is read, lines beginning with the history comment
- character followed immediately by a digit are interpreted as
+ If the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable is set, the time stamp informa-
+ tion associated with each history entry is written to the his-
+ tory file, marked with the history comment character. When the
+ history file is read, lines beginning with the history comment
+ character followed immediately by a digit are interpreted as
timestamps for the following history entry. The return value is
0 unless an invalid option is encountered, an error occurs while
- reading or writing the history file, an invalid _\bo_\bf_\bf_\bs_\be_\bt or range
- is supplied as an argument to -\b-d\bd, or the history expansion sup-
+ reading or writing the history file, an invalid _\bo_\bf_\bf_\bs_\be_\bt or range
+ is supplied as an argument to -\b-d\bd, or the history expansion sup-
plied as an argument to -\b-p\bp fails.
j\bjo\bob\bbs\bs [-\b-l\bln\bnp\bpr\brs\bs] [ _\bj_\bo_\bb_\bs_\bp_\be_\bc ... ]
signal names. If any arguments are supplied when -\b-l\bl is given,
the names of the signals corresponding to the arguments are
listed, and the return status is 0. The _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs argument to
- -\b-l\bl is a number specifying either a signal number or the exit
- status of a process terminated by a signal. The -\b-L\bL option is
- equivalent to -\b-l\bl. k\bki\bil\bll\bl returns true if at least one signal was
+ -\b-l\bl is a number specifying either a signal number or the exit
+ status of a process terminated by a signal. The -\b-L\bL option is
+ equivalent to -\b-l\bl. k\bki\bil\bll\bl returns true if at least one signal was
successfully sent, or false if an error occurs or an invalid op-
tion is encountered.
l\ble\bet\bt _\ba_\br_\bg [_\ba_\br_\bg ...]
Each _\ba_\br_\bg is an arithmetic expression to be evaluated (see A\bAR\bRI\bIT\bTH\bH-\b-
- M\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). If the last _\ba_\br_\bg evaluates to 0,
+ M\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh(1)). If the last _\ba_\br_\bg evaluates to 0,
l\ble\bet\bt returns 1; 0 is returned otherwise.
l\blo\boc\bca\bal\bl [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ... | - ]
- For each argument, a local variable named _\bn_\ba_\bm_\be is created, and
- assigned _\bv_\ba_\bl_\bu_\be. The _\bo_\bp_\bt_\bi_\bo_\bn can be any of the options accepted
+ For each argument, a local variable named _\bn_\ba_\bm_\be is created, and
+ assigned _\bv_\ba_\bl_\bu_\be. The _\bo_\bp_\bt_\bi_\bo_\bn can be any of the options accepted
by d\bde\bec\bcl\bla\bar\bre\be. When l\blo\boc\bca\bal\bl is used within a function, it causes the
variable _\bn_\ba_\bm_\be to have a visible scope restricted to that func-
tion and its children. If _\bn_\ba_\bm_\be is -, the set of shell options
before the function. With no operands, l\blo\boc\bca\bal\bl writes a list of
local variables to the standard output. It is an error to use
l\blo\boc\bca\bal\bl when not within a function. The return status is 0 unless
- l\blo\boc\bca\bal\bl is used outside a function, an invalid _\bn_\ba_\bm_\be is supplied,
+ l\blo\boc\bca\bal\bl is used outside a function, an invalid _\bn_\ba_\bm_\be is supplied,
or _\bn_\ba_\bm_\be is a readonly variable.
l\blo\bog\bgo\bou\but\bt Exit a login shell.
- m\bma\bap\bpf\bfi\bil\ble\be [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC
+ m\bma\bap\bpf\bfi\bil\ble\be [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC
_\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk] [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
r\bre\bea\bad\bda\bar\brr\bra\bay\by [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC
_\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk] [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
- Read lines from the standard input into the indexed array vari-
- able _\ba_\br_\br_\ba_\by, or from file descriptor _\bf_\bd if the -\b-u\bu option is sup-
- plied. The variable M\bMA\bAP\bPF\bFI\bIL\bLE\bE is the default _\ba_\br_\br_\ba_\by. Options, if
+ Read lines from the standard input into the indexed array vari-
+ able _\ba_\br_\br_\ba_\by, or from file descriptor _\bf_\bd if the -\b-u\bu option is sup-
+ plied. The variable M\bMA\bAP\bPF\bFI\bIL\bLE\bE is the default _\ba_\br_\br_\ba_\by. Options, if
supplied, have the following meanings:
- -\b-d\bd The first character of _\bd_\be_\bl_\bi_\bm is used to terminate each
- input line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
+ -\b-d\bd The first character of _\bd_\be_\bl_\bi_\bm is used to terminate each
+ input line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
string, m\bma\bap\bpf\bfi\bil\ble\be will terminate a line when it reads a NUL
character.
-\b-n\bn Copy at most _\bc_\bo_\bu_\bn_\bt lines. If _\bc_\bo_\bu_\bn_\bt is 0, all lines are
p\bpo\bop\bpd\bd [-n\bn] [+_\bn] [-_\bn]
Removes entries from the directory stack. The elements are num-
- bered from 0 starting at the first directory listed by d\bdi\bir\brs\bs.
- With no arguments, p\bpo\bop\bpd\bd removes the top directory from the
+ bered from 0 starting at the first directory listed by d\bdi\bir\brs\bs.
+ With no arguments, p\bpo\bop\bpd\bd removes the top directory from the
stack, and changes to the new top directory. Arguments, if sup-
plied, have the following meanings:
-\b-n\bn Suppresses the normal change of directory when removing
directories from the stack, so that only the stack is ma-
nipulated.
- +\b+_\bn Removes the _\bnth entry counting from the left of the list
- shown by d\bdi\bir\brs\bs, starting with zero, from the stack. For
- example: ``popd +0'' removes the first directory, ``popd
- +1'' the second.
+ +\b+_\bn Removes the _\bnth entry counting from the left of the list
+ shown by d\bdi\bir\brs\bs, starting with zero, from the stack. For
+ example: removes the first directory, the second.
-\b-_\bn Removes the _\bnth entry counting from the right of the list
- shown by d\bdi\bir\brs\bs, starting with zero. For example: ``popd
- -0'' removes the last directory, ``popd -1'' the next to
- last.
+ shown by d\bdi\bir\brs\bs, starting with zero. For example: removes
+ the last directory, the next to last.
If the top element of the directory stack is modified, and the
_\b-_\bn option was not supplied, p\bpo\bop\bpd\bd uses the c\bcd\bd builtin to change
to the directory at the top of the stack. If the c\bcd\bd fails, p\bpo\bop\bpd\bd
returns a non-zero value.
- Otherwise, p\bpo\bop\bpd\bd returns false if an invalid option is encoun-
+ Otherwise, p\bpo\bop\bpd\bd returns false if an invalid option is encoun-
tered, the directory stack is empty, or a non-existent directory
stack entry is specified.
ifiers:
%\b%b\bb causes p\bpr\bri\bin\bnt\btf\bf to expand backslash escape sequences in the
corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in the same way as e\bec\bch\bho\bo -\b-e\be.
- %\b%q\bq causes p\bpr\bri\bin\bnt\btf\bf to output the corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in a
- format that can be reused as shell input. %\b%q\bq and %\b%Q\bQ use
- the $\b$'\b''\b' quoting style if any characters in the argument
- string require it, and backslash quoting otherwise. If
- the format string uses the _\bp_\br_\bi_\bn_\bt_\bf alternate form, these
+ %\b%q\bq causes p\bpr\bri\bin\bnt\btf\bf to output the corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in a
+ format that can be reused as shell input. %\b%q\bq and %\b%Q\bQ use
+ the $\b$'\b''\b' quoting style if any characters in the argument
+ string require it, and backslash quoting otherwise. If
+ the format string uses the _\bp_\br_\bi_\bn_\bt_\bf alternate form, these
two formats quote the argument string using single
quotes.
- %\b%Q\bQ like %\b%q\bq, but applies any supplied precision to the _\ba_\br_\bg_\bu_\b-
+ %\b%Q\bQ like %\b%q\bq, but applies any supplied precision to the _\ba_\br_\bg_\bu_\b-
_\bm_\be_\bn_\bt before quoting it.
%\b%(\b(_\bd_\ba_\bt_\be_\bf_\bm_\bt)\b)T\bT
- causes p\bpr\bri\bin\bnt\btf\bf to output the date-time string resulting
- from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
+ causes p\bpr\bri\bin\bnt\btf\bf to output the date-time string resulting
+ from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
The corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt is an integer representing the
number of seconds since the epoch. Two special argument
values may be used: -1 represents the current time, and
-2 represents the time the shell was invoked. If no ar-
gument is specified, conversion behaves as if -1 had been
- given. This is an exception to the usual p\bpr\bri\bin\bnt\btf\bf behav-
+ given. This is an exception to the usual p\bpr\bri\bin\bnt\btf\bf behav-
ior.
The %b, %q, and %T format specifiers all use the field width and
precision arguments from the format specification and write that
- many bytes from (or use that wide a field for) the expanded ar-
- gument, which usually contains more characters than the origi-
+ many bytes from (or use that wide a field for) the expanded ar-
+ gument, which usually contains more characters than the origi-
nal.
The %n format specifier accepts a corresponding argument that is
Arguments to non-string format specifiers are treated as C con-
stants, except that a leading plus or minus sign is allowed, and
- if the leading character is a single or double quote, the value
+ if the leading character is a single or double quote, the value
is the ASCII value of the following character.
- The _\bf_\bo_\br_\bm_\ba_\bt is reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
+ The _\bf_\bo_\br_\bm_\ba_\bt is reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
_\bm_\be_\bn_\bt_\bs. If the _\bf_\bo_\br_\bm_\ba_\bt requires more _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs than are supplied,
the extra format specifications behave as if a zero value or
null string, as appropriate, had been supplied. The return
_\bd_\bi_\br Adds _\bd_\bi_\br to the directory stack at the top
After the stack has been modified, if the -\b-n\bn option was not sup-
- plied, p\bpu\bus\bsh\bhd\bd uses the c\bcd\bd builtin to change to the directory at
+ plied, p\bpu\bus\bsh\bhd\bd uses the c\bcd\bd builtin to change to the directory at
the top of the stack. If the c\bcd\bd fails, p\bpu\bus\bsh\bhd\bd returns a non-zero
value.
occurs while reading the name of the current directory or an in-
valid option is supplied.
- r\bre\bea\bad\bd [-\b-E\bEe\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-i\bi _\bt_\be_\bx_\bt] [-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs] [-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs]
+ r\bre\bea\bad\bd [-\b-E\bEe\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-i\bi _\bt_\be_\bx_\bt] [-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs] [-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs]
[-\b-p\bp _\bp_\br_\bo_\bm_\bp_\bt] [-\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt] [-\b-u\bu _\bf_\bd] [_\bn_\ba_\bm_\be ...]
One line is read from the standard input, or from the file de-
scriptor _\bf_\bd supplied as an argument to the -\b-u\bu option, split into
- words as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the
+ words as described in _\bb_\ba_\bs_\bh (1) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the
first word is assigned to the first _\bn_\ba_\bm_\be, the second word to the
second _\bn_\ba_\bm_\be, and so on. If there are more words than names, the
remaining words and their intervening delimiters are assigned to
stream than names, the remaining names are assigned empty val-
ues. The characters in I\bIF\bFS\bS are used to split the line into
words using the same rules the shell uses for expansion (de-
- scribed in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg). The backslash charac-
- ter (\\b\) may be used to remove any special meaning for the next
+ scribed in _\bb_\ba_\bs_\bh (1) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg). The backslash char-
+ acter (\\b\) may be used to remove any special meaning for the next
character read and for line continuation. Options, if supplied,
have the following meanings:
-\b-a\ba _\ba_\bn_\ba_\bm_\be
nored.
-\b-d\bd _\bd_\be_\bl_\bi_\bm
The first character of _\bd_\be_\bl_\bi_\bm is used to terminate the in-
- put line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
- string, r\bre\bea\bad\bd will terminate a line when it reads a NUL
+ put line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
+ string, r\bre\bea\bad\bd will terminate a line when it reads a NUL
character.
- -\b-e\be If the standard input is coming from a terminal, r\bre\bea\bad\bd
- uses r\bre\bea\bad\bdl\bli\bin\bne\be (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) to obtain the
- line. Readline uses the current (or default, if line
- editing was not previously active) editing settings, but
+ -\b-e\be If the standard input is coming from a terminal, r\bre\bea\bad\bd
+ uses r\bre\bea\bad\bdl\bli\bin\bne\be (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in _\bb_\ba_\bs_\bh(1)) to obtain the
+ line. Readline uses the current (or default, if line
+ editing was not previously active) editing settings, but
uses readline's default filename completion.
- -\b-E\bE If the standard input is coming from a terminal, r\bre\bea\bad\bd
- uses r\bre\bea\bad\bdl\bli\bin\bne\be (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) to obtain the
- line. Readline uses the current (or default, if line
- editing was not previously active) editing settings, but
- uses bash's default completion, including programmable
+ -\b-E\bE If the standard input is coming from a terminal, r\bre\bea\bad\bd
+ uses r\bre\bea\bad\bdl\bli\bin\bne\be (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in _\bb_\ba_\bs_\bh(1)) to obtain the
+ line. Readline uses the current (or default, if line
+ editing was not previously active) editing settings, but
+ uses bash's default completion, including programmable
completion.
-\b-i\bi _\bt_\be_\bx_\bt
- If r\bre\bea\bad\bdl\bli\bin\bne\be is being used to read the line, _\bt_\be_\bx_\bt is
+ If r\bre\bea\bad\bdl\bli\bin\bne\be is being used to read the line, _\bt_\be_\bx_\bt is
placed into the editing buffer before editing begins.
-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs
- r\bre\bea\bad\bd returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
+ r\bre\bea\bad\bd returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
waiting for a complete line of input, but honors a delim-
iter if fewer than _\bn_\bc_\bh_\ba_\br_\bs characters are read before the
delimiter.
-\b-s\bs Silent mode. If input is coming from a terminal, charac-
ters are not echoed.
-\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt
- Cause r\bre\bea\bad\bd to time out and return failure if a complete
- line of input (or a specified number of characters) is
- not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a deci-
- mal number with a fractional portion following the deci-
- mal point. This option is only effective if r\bre\bea\bad\bd is
- reading input from a terminal, pipe, or other special
- file; it has no effect when reading from regular files.
+ Cause r\bre\bea\bad\bd to time out and return failure if a complete
+ line of input (or a specified number of characters) is
+ not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a deci-
+ mal number with a fractional portion following the deci-
+ mal point. This option is only effective if r\bre\bea\bad\bd is
+ reading input from a terminal, pipe, or other special
+ file; it has no effect when reading from regular files.
If r\bre\bea\bad\bd times out, r\bre\bea\bad\bd saves any partial input read into
the specified variable _\bn_\ba_\bm_\be. If _\bt_\bi_\bm_\be_\bo_\bu_\bt is 0, r\bre\bea\bad\bd re-
turns immediately, without trying to read any data. The
timeout is exceeded.
-\b-u\bu _\bf_\bd Read input from file descriptor _\bf_\bd.
- If no _\bn_\ba_\bm_\be_\bs are supplied, the line read, without the ending de-
- limiter but otherwise unmodified, is assigned to the variable
- R\bRE\bEP\bPL\bLY\bY. The exit status is zero, unless end-of-file is encoun-
- tered, r\bre\bea\bad\bd times out (in which case the status is greater than
- 128), a variable assignment error (such as assigning to a read-
+ Other than the case where _\bd_\be_\bl_\bi_\bm is the empty string, r\bre\bea\bad\bd ig-
+ nores any NUL characters in the input.
+
+ If no _\bn_\ba_\bm_\be_\bs are supplied, the line read, without the ending de-
+ limiter but otherwise unmodified, is assigned to the variable
+ R\bRE\bEP\bPL\bLY\bY. The exit status is zero, unless end-of-file is encoun-
+ tered, r\bre\bea\bad\bd times out (in which case the status is greater than
+ 128), a variable assignment error (such as assigning to a read-
only variable) occurs, or an invalid file descriptor is supplied
as the argument to -\b-u\bu.
marked. The -\b-a\ba option restricts the variables to indexed ar-
rays; the -\b-A\bA option restricts the variables to associative ar-
rays. If both options are supplied, -\b-A\bA takes precedence. If no
- _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
+ _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
list of all readonly names is printed. The other options may be
used to restrict the output to a subset of the set of readonly
names. The -\b-p\bp option causes output to be displayed in a format
a _\bn_\ba_\bm_\be that is not a function.
r\bre\bet\btu\bur\brn\bn [_\bn]
- Causes a function to stop executing and return the value speci-
- fied by _\bn to its caller. If _\bn is omitted, the return status is
- that of the last command executed in the function body. If r\bre\be-\b-
+ Causes a function to stop executing and return the value speci-
+ fied by _\bn to its caller. If _\bn is omitted, the return status is
+ that of the last command executed in the function body. If r\bre\be-\b-
t\btu\bur\brn\bn is executed by a trap handler, the last command used to de-
termine the status is the last command executed before the trap
handler. If r\bre\bet\btu\bur\brn\bn is executed during a D\bDE\bEB\bBU\bUG\bG trap, the last
that script and return either _\bn or the exit status of the last
command executed within the script as the exit status of the
script. If _\bn is supplied, the return value is its least signif-
- icant 8 bits. The return status is non-zero if r\bre\bet\btu\bur\brn\bn is sup-
- plied a non-numeric argument, or is used outside a function and
- not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be. Any command
+ icant 8 bits. The return status is non-zero if r\bre\bet\btu\bur\brn\bn is sup-
+ plied a non-numeric argument, or is used outside a function and
+ not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be. Any command
associated with the R\bRE\bET\bTU\bUR\bRN\bN trap is executed before execution re-
sumes after the function or script.
s\bse\bet\bt +\b+o\bo Without options, display the name and value of each shell vari-
able in a format that can be reused as input for setting or re-
setting the currently-set variables. Read-only variables cannot
- be reset. In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed. The
- output is sorted according to the current locale. When options
- are specified, they set or unset shell attributes. Any argu-
- ments remaining after option processing are treated as values
+ be reset. In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed. The
+ output is sorted according to the current locale. When options
+ are specified, they set or unset shell attributes. Any argu-
+ ments remaining after option processing are treated as values
for the positional parameters and are assigned, in order, to $\b$1\b1,
- $\b$2\b2, .\b..\b..\b. $\b$_\bn. Options, if specified, have the following mean-
+ $\b$2\b2, ..., $\b$_\bn. Options, if specified, have the following mean-
ings:
-\b-a\ba Each variable or function that is created or modified is
- given the export attribute and marked for export to the
+ given the export attribute and marked for export to the
environment of subsequent commands.
- -\b-b\bb Report the status of terminated background jobs immedi-
+ -\b-b\bb Report the status of terminated background jobs immedi-
ately, rather than before the next primary prompt. This
is effective only when job control is enabled.
-\b-e\be Exit immediately if a _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be (which may consist of a
single _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd), a _\bl_\bi_\bs_\bt, or a _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd _\bc_\bo_\bm_\bm_\ba_\bn_\bd
- (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh_\b(_\b1_\b)), exits with a non-zero
+ (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh(1)), exits with a non-zero
status. The shell does not exit if the command that
fails is part of the command list immediately following
a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test following the
- i\bif\bf or e\bel\bli\bif\bf reserved words, part of any command executed
- in a &\b&&\b& or |\b||\b| list except the command following the fi-
+ i\bif\bf or e\bel\bli\bif\bf reserved words, part of any command executed
+ in a &\b&&\b& or |\b||\b| list except the command following the fi-
nal &\b&&\b& or |\b||\b|, any command in a pipeline but the last, or
if the command's return value is being inverted with !\b!.
If a compound command other than a subshell returns a
if set, is executed before the shell exits. This option
applies to the shell environment and each subshell envi-
ronment separately (see C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bNM\bME\bEN\bNT\bT in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b)), and may cause subshells to exit before execut-
+ _\bb_\ba_\bs_\bh(1)), and may cause subshells to exit before execut-
ing all the commands in the subshell.
If a compound command or shell function executes in a
that precede the command name.
-\b-m\bm Monitor mode. Job control is enabled. This option is
on by default for interactive shells on systems that
- support it (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). All processes
+ support it (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh(1)). All processes
run in a separate process group. When a background job
completes, the shell prints a line containing its exit
status.
-\b-n\bn Read commands but do not execute them. This may be used
- to check a shell script for syntax errors. This is ig-
+ to check a shell script for syntax errors. This is ig-
nored by interactive shells.
-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
The _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be can be one of the following:
Same as -\b-a\ba.
b\bbr\bra\bac\bce\bee\bex\bxp\bpa\ban\bnd\bd
Same as -\b-B\bB.
- e\bem\bma\bac\bcs\bs Use an emacs-style command line editing inter-
+ e\bem\bma\bac\bcs\bs Use an emacs-style command line editing inter-
face. This is enabled by default when the shell
is interactive, unless the shell is started with
- the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option. This also affects the
+ the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option. This also affects the
editing interface used for r\bre\bea\bad\bd -\b-e\be.
e\ber\brr\bre\bex\bxi\bit\bt Same as -\b-e\be.
e\ber\brr\brt\btr\bra\bac\bce\be
h\bha\bas\bsh\bha\bal\bll\bl Same as -\b-h\bh.
h\bhi\bis\bst\bte\bex\bxp\bpa\ban\bnd\bd
Same as -\b-H\bH.
- h\bhi\bis\bst\bto\bor\bry\by Enable command history, as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b)
- under H\bHI\bIS\bST\bTO\bOR\bRY\bY. This option is on by default in
+ h\bhi\bis\bst\bto\bor\bry\by Enable command history, as described in _\bb_\ba_\bs_\bh(1)
+ under H\bHI\bIS\bST\bTO\bOR\bRY\bY. This option is on by default in
interactive shells.
i\big\bgn\bno\bor\bre\bee\beo\bof\bf
- The effect is as if the shell command ``IG-
- NOREEOF=10'' had been executed (see S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bi-\b-
- a\bab\bbl\ble\bes\bs in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
+ The effect is as if the shell command had been
+ executed (see S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs in _\bb_\ba_\bs_\bh(1)).
k\bke\bey\byw\bwo\bor\brd\bd Same as -\b-k\bk.
m\bmo\bon\bni\bit\bto\bor\br Same as -\b-m\bm.
n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br
p\bpo\bos\bsi\bix\bx Change the behavior of b\bba\bas\bsh\bh where the default
operation differs from the POSIX standard to
match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be). See S\bSE\bEE\bE A\bAL\bLS\bSO\bO
- in _\bb_\ba_\bs_\bh_\b(_\b1_\b) for a reference to a document that
+ in _\bb_\ba_\bs_\bh(1) for a reference to a document that
details how posix mode affects bash's behavior.
p\bpr\bri\biv\bvi\bil\ble\beg\bge\bed\bd
Same as -\b-p\bp.
This also affects the editing interface used for
r\bre\bea\bad\bd -\b-e\be.
x\bxt\btr\bra\bac\bce\be Same as -\b-x\bx.
- If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints the
- current shell option settings. If +\b+o\bo is supplied with
- no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints a series of s\bse\bet\bt commands to
- recreate the current option settings on the standard
+ If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints the
+ current shell option settings. If +\b+o\bo is supplied with
+ no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, s\bse\bet\bt prints a series of s\bse\bet\bt commands to
+ recreate the current option settings on the standard
output.
- -\b-p\bp Turn on _\bp_\br_\bi_\bv_\bi_\bl_\be_\bg_\be_\bd mode. In this mode, the $\b$E\bEN\bNV\bV and
- $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV files are not processed, shell functions are
- not inherited from the environment, and the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
- B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
- pear in the environment, are ignored. If the shell is
- started with the effective user (group) id not equal to
- the real user (group) id, and the -\b-p\bp option is not sup-
+ -\b-p\bp Turn on _\bp_\br_\bi_\bv_\bi_\bl_\be_\bg_\be_\bd mode. In this mode, the $\b$E\bEN\bNV\bV and
+ $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV files are not processed, shell functions are
+ not inherited from the environment, and the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
+ B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
+ pear in the environment, are ignored. If the shell is
+ started with the effective user (group) id not equal to
+ the real user (group) id, and the -\b-p\bp option is not sup-
plied, these actions are taken and the effective user id
is set to the real user id. If the -\b-p\bp option is sup-
plied at startup, the effective user id is not reset.
set once it has been set.
-\b-t\bt Exit after reading and executing one command.
-\b-u\bu Treat unset variables and parameters other than the spe-
- cial parameters "@" and "*", or array variables sub-
- scripted with "@" or "*", as an error when performing
- parameter expansion. If expansion is attempted on an
- unset variable or parameter, the shell prints an error
- message, and, if not interactive, exits with a non-zero
- status.
+ cial parameters and or array variables subscripted with
+ or as an error when performing parameter expansion. If
+ expansion is attempted on an unset variable or parame-
+ ter, the shell prints an error message, and, if not in-
+ teractive, exits with a non-zero status.
-\b-v\bv Print shell input lines as they are read.
- -\b-x\bx After expanding each _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, f\bfo\bor\br command, c\bca\bas\bse\be
+ -\b-x\bx After expanding each _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, f\bfo\bor\br command, c\bca\bas\bse\be
command, s\bse\bel\ble\bec\bct\bt command, or arithmetic f\bfo\bor\br command, dis-
play the expanded value of P\bPS\bS4\b4, followed by the command
and its expanded arguments or associated word list, to
standard error.
-\b-B\bB The shell performs brace expansion (see B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
- in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). This is on by default.
+ in _\bb_\ba_\bs_\bh(1)). This is on by default.
-\b-C\bC If set, b\bba\bas\bsh\bh does not overwrite an existing file with
the >\b>, >\b>&\b&, and <\b<>\b> redirection operators. This may be
overridden when creating output files by using the redi-
ited in such cases.
-\b-H\bH Enable !\b! style history substitution. This option is on
by default when the shell is interactive.
- -\b-P\bP If set, the shell does not resolve symbolic links when
- executing commands such as c\bcd\bd that change the current
+ -\b-P\bP If set, the shell does not resolve symbolic links when
+ executing commands such as c\bcd\bd that change the current
working directory. It uses the physical directory
structure instead. By default, b\bba\bas\bsh\bh follows the logical
chain of directories when performing commands which
change the current directory.
-\b-T\bT If set, any traps on D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN are inherited by
shell functions, command substitutions, and commands ex-
- ecuted in a subshell environment. The D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN
+ ecuted in a subshell environment. The D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN
traps are normally not inherited in such cases.
- -\b--\b- If no arguments follow this option, then the positional
+ -\b--\b- If no arguments follow this option, then the positional
parameters are unset. Otherwise, the positional parame-
ters are set to the _\ba_\br_\bgs, even if some of them begin
with a -\b-.
The options are off by default unless otherwise noted. Using +
rather than - causes these options to be turned off. The op-
tions can also be specified as arguments to an invocation of the
- shell. The current set of options may be found in $\b$-\b-. The re-
- turn status is always true unless an invalid option is encoun-
+ shell. The current set of options may be found in $\b$-\b-. The re-
+ turn status is always true unless an invalid option is encoun-
tered.
s\bsh\bhi\bif\bft\bt [_\bn]
- The positional parameters from _\bn+1 ... are renamed to $\b$1\b1 .\b..\b..\b..\b.
- Parameters represented by the numbers $\b$#\b# down to $\b$#\b#-_\bn+1 are un-
- set. _\bn must be a non-negative number less than or equal to $\b$#\b#.
- If _\bn is 0, no parameters are changed. If _\bn is not given, it is
- assumed to be 1. If _\bn is greater than $\b$#\b#, the positional param-
- eters are not changed. The return status is greater than zero
+ The positional parameters from _\bn+1 ... are renamed to $\b$1\b1 .\b..\b..\b..\b.
+ Parameters represented by the numbers $\b$#\b# down to $\b$#\b#-_\bn+1 are un-
+ set. _\bn must be a non-negative number less than or equal to $\b$#\b#.
+ If _\bn is 0, no parameters are changed. If _\bn is not given, it is
+ assumed to be 1. If _\bn is greater than $\b$#\b#, the positional para-
+ meters are not changed. The return status is greater than zero
if _\bn is greater than $\b$#\b# or less than zero; otherwise 0.
s\bsh\bho\bop\bpt\bt [-\b-p\bpq\bqs\bsu\bu] [-\b-o\bo] [_\bo_\bp_\bt_\bn_\ba_\bm_\be ...]
- Toggle the values of settings controlling optional shell behav-
- ior. The settings can be either those listed below, or, if the
+ Toggle the values of settings controlling optional shell behav-
+ ior. The settings can be either those listed below, or, if the
-\b-o\bo option is used, those available with the -\b-o\bo option to the s\bse\bet\bt
builtin command. With no options, or with the -\b-p\bp option, a list
- of all settable options is displayed, with an indication of
+ of all settable options is displayed, with an indication of
whether or not each is set; if _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are supplied, the output
is restricted to those options. The -\b-p\bp option causes output to
be displayed in a form that may be reused as input. Other op-
-\b-u\bu Disable (unset) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
-\b-q\bq Suppresses normal output (quiet mode); the return status
indicates whether the _\bo_\bp_\bt_\bn_\ba_\bm_\be is set or unset. If multi-
- ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return sta-
- tus is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
+ ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return sta-
+ tus is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
wise.
- -\b-o\bo Restricts the values of _\bo_\bp_\bt_\bn_\ba_\bm_\be to be those defined for
+ -\b-o\bo Restricts the values of _\bo_\bp_\bt_\bn_\ba_\bm_\be to be those defined for
the -\b-o\bo option to the s\bse\bet\bt builtin.
- If either -\b-s\bs or -\b-u\bu is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, s\bsh\bho\bop\bpt\bt
- shows only those options which are set or unset, respectively.
- Unless otherwise noted, the s\bsh\bho\bop\bpt\bt options are disabled (unset)
+ If either -\b-s\bs or -\b-u\bu is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, s\bsh\bho\bop\bpt\bt
+ shows only those options which are set or unset, respectively.
+ Unless otherwise noted, the s\bsh\bho\bop\bpt\bt options are disabled (unset)
by default.
- The return status when listing options is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs
- are enabled, non-zero otherwise. When setting or unsetting op-
- tions, the return status is zero unless an _\bo_\bp_\bt_\bn_\ba_\bm_\be is not a
+ The return status when listing options is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs
+ are enabled, non-zero otherwise. When setting or unsetting op-
+ tions, the return status is zero unless an _\bo_\bp_\bt_\bn_\ba_\bm_\be is not a
valid shell option.
The list of s\bsh\bho\bop\bpt\bt options is:
a\bar\brr\bra\bay\by_\b_e\bex\bxp\bpa\ban\bnd\bd_\b_o\bon\bnc\bce\be
- If set, the shell suppresses multiple evaluation of as-
+ If set, the shell suppresses multiple evaluation of as-
sociative and indexed array subscripts during arithmetic
expression evaluation, while executing builtins that can
- perform variable assignments, and while executing
+ perform variable assignments, and while executing
builtins that perform array dereferencing.
a\bas\bss\bso\boc\bc_\b_e\bex\bxp\bpa\ban\bnd\bd_\b_o\bon\bnc\bce\be
Deprecated; a synonym for a\bar\brr\bra\bay\by_\b_e\bex\bxp\bpa\ban\bnd\bd_\b_o\bon\bnc\bce\be.
- a\bau\but\bto\boc\bcd\bd If set, a command name that is the name of a directory
- is executed as if it were the argument to the c\bcd\bd com-
+ a\bau\but\bto\boc\bcd\bd If set, a command name that is the name of a directory
+ is executed as if it were the argument to the c\bcd\bd com-
mand. This option is only used by interactive shells.
c\bcd\bda\bab\bbl\ble\be_\b_v\bva\bar\brs\bs
- If set, an argument to the c\bcd\bd builtin command that is
- not a directory is assumed to be the name of a variable
+ If set, an argument to the c\bcd\bd builtin command that is
+ not a directory is assumed to be the name of a variable
whose value is the directory to change to.
c\bcd\bds\bsp\bpe\bel\bll\bl If set, minor errors in the spelling of a directory com-
ponent in a c\bcd\bd command will be corrected. The errors
checked for are transposed characters, a missing charac-
- ter, and one character too many. If a correction is
- found, the corrected filename is printed, and the com-
- mand proceeds. This option is only used by interactive
+ ter, and one character too many. If a correction is
+ found, the corrected filename is printed, and the com-
+ mand proceeds. This option is only used by interactive
shells.
c\bch\bhe\bec\bck\bkh\bha\bas\bsh\bh
If set, b\bba\bas\bsh\bh checks that a command found in the hash ta-
formed.
c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs
If set, b\bba\bas\bsh\bh lists the status of any stopped and running
- jobs before exiting an interactive shell. If any jobs
+ jobs before exiting an interactive shell. If any jobs
are running, this causes the exit to be deferred until a
second exit is attempted without an intervening command
- (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The shell always post-
+ (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh(1)). The shell always post-
pones exiting if any jobs are stopped.
c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be
If set, b\bba\bas\bsh\bh checks the window size after each external
line command in the same history entry. This allows
easy re-editing of multi-line commands. This option is
enabled by default, but only has an effect if command
- history is enabled, as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under H\bHI\bIS\bS-\b-
+ history is enabled, as described in _\bb_\ba_\bs_\bh(1) under H\bHI\bIS\bS-\b-
T\bTO\bOR\bRY\bY.
c\bco\bom\bmp\bpa\bat\bt3\b31\b1
c\bco\bom\bmp\bpa\bat\bt3\b32\b2
c\bco\bom\bmp\bpa\bat\bt4\b44\b4
c\bco\bom\bmp\bpa\bat\bt5\b50\b0
These control aspects of the shell's compatibility mode
- (see S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
+ (see S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE in _\bb_\ba_\bs_\bh(1)).
c\bco\bom\bmp\bpl\ble\bet\bte\be_\b_f\bfu\bul\bll\blq\bqu\buo\bot\bte\be
If set, b\bba\bas\bsh\bh quotes all shell metacharacters in file-
names and directory names when performing completion.
If not set, b\bba\bas\bsh\bh removes metacharacters such as the dol-
- lar sign from the set of characters that will be quoted
- in completed filenames when these metacharacters appear
- in shell variable references in words to be completed.
- This means that dollar signs in variable names that ex-
- pand to directories will not be quoted; however, any
- dollar signs appearing in filenames will not be quoted,
- either. This is active only when bash is using back-
- slashes to quote completed filenames. This variable is
- set by default, which is the default bash behavior in
+ lar sign from the set of characters that will be quoted
+ in completed filenames when these metacharacters appear
+ in shell variable references in words to be completed.
+ This means that dollar signs in variable names that ex-
+ pand to directories will not be quoted; however, any
+ dollar signs appearing in filenames will not be quoted,
+ either. This is active only when bash is using back-
+ slashes to quote completed filenames. This variable is
+ set by default, which is the default bash behavior in
versions through 4.2.
d\bdi\bir\bre\bex\bxp\bpa\ban\bnd\bd
- If set, b\bba\bas\bsh\bh replaces directory names with the results
- of word expansion when performing filename completion.
- This changes the contents of the readline editing buf-
- fer. If not set, b\bba\bas\bsh\bh attempts to preserve what the
+ If set, b\bba\bas\bsh\bh replaces directory names with the results
+ of word expansion when performing filename completion.
+ This changes the contents of the readline editing
+ buffer. If not set, b\bba\bas\bsh\bh attempts to preserve what the
user typed.
d\bdi\bir\brs\bsp\bpe\bel\bll\bl
- If set, b\bba\bas\bsh\bh attempts spelling correction on directory
- names during word completion if the directory name ini-
+ If set, b\bba\bas\bsh\bh attempts spelling correction on directory
+ names during word completion if the directory name ini-
tially supplied does not exist.
- d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a `.' in
- the results of pathname expansion. The filenames `\b``\b`.\b.'\b''\b'
- and `\b``\b`.\b..\b.'\b''\b' must always be matched explicitly, even if
- d\bdo\bot\btg\bgl\blo\bob\bb is set.
+ d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a in the
+ results of pathname expansion. The filenames and must
+ always be matched explicitly, even if d\bdo\bot\btg\bgl\blo\bob\bb is set.
e\bex\bxe\bec\bcf\bfa\bai\bil\bl
If set, a non-interactive shell will not exit if it can-
- not execute the file specified as an argument to the
- e\bex\bxe\bec\bc builtin command. An interactive shell does not
+ not execute the file specified as an argument to the
+ e\bex\bxe\bec\bc builtin command. An interactive shell does not
exit if e\bex\bxe\bec\bc fails.
e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs
- If set, aliases are expanded as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) un-
+ If set, aliases are expanded as described in _\bb_\ba_\bs_\bh(1) un-
der A\bAL\bLI\bIA\bAS\bSE\bES\bS. This option is enabled by default for in-
teractive shells.
e\bex\bxt\btd\bde\beb\bbu\bug\bg
If set at shell invocation, or in a shell startup file,
arrange to execute the debugger profile before the shell
- starts, identical to the -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option. If set af-
- ter invocation, behavior intended for use by debuggers
+ starts, identical to the -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option. If set af-
+ ter invocation, behavior intended for use by debuggers
is enabled:
1\b1.\b. The -\b-F\bF option to the d\bde\bec\bcl\bla\bar\bre\be builtin displays the
source file name and line number corresponding to
each function name supplied as an argument.
- 2\b2.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
- non-zero value, the next command is skipped and
+ 2\b2.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
+ non-zero value, the next command is skipped and
not executed.
- 3\b3.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
- value of 2, and the shell is executing in a sub-
- routine (a shell function or a shell script exe-
- cuted by the .\b. or s\bso\bou\bur\brc\bce\be builtins), the shell
+ 3\b3.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
+ value of 2, and the shell is executing in a sub-
+ routine (a shell function or a shell script exe-
+ cuted by the .\b. or s\bso\bou\bur\brc\bce\be builtins), the shell
simulates a call to r\bre\bet\btu\bur\brn\bn.
- 4\b4.\b. B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
- in their descriptions in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
+ 4\b4.\b. B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
+ in their descriptions in _\bb_\ba_\bs_\bh(1)).
- 5\b5.\b. Function tracing is enabled: command substitu-
+ 5\b5.\b. Function tracing is enabled: command substitu-
tion, shell functions, and subshells invoked with
(\b( _\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps.
_\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the E\bER\bRR\bR trap.
e\bex\bxt\btg\bgl\blo\bob\bb If set, the extended pattern matching features described
- in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn are enabled.
+ in _\bb_\ba_\bs_\bh(1) under P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn are enabled.
e\bex\bxt\btq\bqu\buo\bot\bte\be
- If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
- within $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b} expansions enclosed in double
+ If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
+ within $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b} expansions enclosed in double
quotes. This option is enabled by default.
f\bfa\bai\bil\blg\bgl\blo\bob\bb
- If set, patterns which fail to match filenames during
+ If set, patterns which fail to match filenames during
pathname expansion result in an expansion error.
f\bfo\bor\brc\bce\be_\b_f\bfi\big\bgn\bno\bor\bre\be
- If set, the suffixes specified by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
- variable cause words to be ignored when performing word
+ If set, the suffixes specified by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
+ variable cause words to be ignored when performing word
completion even if the ignored words are the only possi-
- ble completions. See S\bSH\bHE\bEL\bLL\bL V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b) for a
+ ble completions. See S\bSH\bHE\bEL\bLL\bL V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS in _\bb_\ba_\bs_\bh(1) for a
description of F\bFI\bIG\bGN\bNO\bOR\bRE\bE. This option is enabled by de-
fault.
g\bgl\blo\bob\bba\bas\bsc\bci\bii\bir\bra\ban\bng\bge\bes\bs
If set, range expressions used in pattern matching
- bracket expressions (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg in _\bb_\ba_\bs_\bh_\b(_\b1_\b))
+ bracket expressions (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg in _\bb_\ba_\bs_\bh(1))
behave as if in the traditional C locale when performing
- comparisons. That is, the current locale's collating
- sequence is not taken into account, so b\bb will not col-
- late between A\bA and B\bB, and upper-case and lower-case
+ comparisons. That is, the current locale's collating
+ sequence is not taken into account, so b\bb will not col-
+ late between A\bA and B\bB, and upper-case and lower-case
ASCII characters will collate together.
g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs
- If set, pathname expansion will never match the file-
- names `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b', even if the pattern begins with
- a `\b``\b`.\b.'\b''\b'. This option is enabled by default.
+ If set, pathname expansion will never match the file-
+ names and even if the pattern begins with a This option
+ is enabled by default.
g\bgl\blo\bob\bbs\bst\bta\bar\br
If set, the pattern *\b**\b* used in a pathname expansion con-
GNU error message format.
h\bhi\bis\bst\bta\bap\bpp\bpe\ben\bnd\bd
- If set, the history list is appended to the file named
+ If set, the history list is appended to the file named
by the value of the H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE variable when the shell ex-
its, rather than overwriting the file.
If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will attempt to
perform hostname completion when a word containing a @\b@
is being completed (see C\bCo\bom\bmp\bpl\ble\bet\bti\bin\bng\bg under R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b)). This is enabled by default.
+ _\bb_\ba_\bs_\bh(1)). This is enabled by default.
h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt
If set, b\bba\bas\bsh\bh will send S\bSI\bIG\bGH\bHU\bUP\bP to all jobs when an inter-
active login shell exits.
i\bin\bnh\bhe\ber\bri\bit\bt_\b_e\ber\brr\bre\bex\bxi\bit\bt
- If set, command substitution inherits the value of the
- e\ber\brr\bre\bex\bxi\bit\bt option, instead of unsetting it in the subshell
- environment. This option is enabled when _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be is
+ If set, command substitution inherits the value of the
+ e\ber\brr\bre\bex\bxi\bit\bt option, instead of unsetting it in the subshell
+ environment. This option is enabled when _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be is
enabled.
i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs
If set, allow a word beginning with #\b# to cause that word
and all remaining characters on that line to be ignored
- in an interactive shell (see C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). This
+ in an interactive shell (see C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS in _\bb_\ba_\bs_\bh(1)). This
option is enabled by default.
l\bla\bas\bst\btp\bpi\bip\bpe\be
- If set, and job control is not active, the shell runs
+ If set, and job control is not active, the shell runs
the last command of a pipeline not executed in the back-
ground in the current shell environment.
l\blo\bog\bgi\bin\bn_\b_s\bsh\bhe\bel\bll\bl
The shell sets this option if it is started as a login
- shell (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The value may not be
+ shell (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh(1)). The value may not be
changed.
m\bma\bai\bil\blw\bwa\bar\brn\bn
- If set, and a file that b\bba\bas\bsh\bh is checking for mail has
- been accessed since the last time it was checked, the
- message ``The mail in _\bm_\ba_\bi_\bl_\bf_\bi_\bl_\be has been read'' is dis-
- played.
+ If set, and a file that b\bba\bas\bsh\bh is checking for mail has
+ been accessed since the last time it was checked, b\bba\bas\bsh\bh
+ displays the message
n\bno\bo_\b_e\bem\bmp\bpt\bty\by_\b_c\bcm\bmd\bd_\b_c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn
If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will not at-
n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb
If set, b\bba\bas\bsh\bh matches filenames in a case-insensitive
fashion when performing pathname expansion (see P\bPa\bat\bth\bhn\bna\bam\bme\be
- E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
+ E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in _\bb_\ba_\bs_\bh(1)).
n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh
- If set, b\bba\bas\bsh\bh matches patterns in a case-insensitive
+ If set, b\bba\bas\bsh\bh matches patterns in a case-insensitive
fashion when performing matching while executing c\bca\bas\bse\be or
[\b[[\b[ conditional commands, when performing pattern substi-
- tution word expansions, or when filtering possible com-
+ tution word expansions, or when filtering possible com-
pletions as part of programmable completion.
n\bno\boe\bex\bxp\bpa\ban\bnd\bd_\b_t\btr\bra\ban\bns\bsl\bla\bat\bti\bio\bon\bn
- If set, b\bba\bas\bsh\bh encloses the translated results of $"..."
- quoting in single quotes instead of double quotes. If
+ If set, b\bba\bas\bsh\bh encloses the translated results of $\b$"\b"..."\b"
+ quoting in single quotes instead of double quotes. If
the string is not translated, this has no effect.
n\bnu\bul\bll\blg\bgl\blo\bob\bb
If set, pathname expansion patterns which match no files
- (see P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) expand to nothing
+ (see P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in _\bb_\ba_\bs_\bh(1)) expand to nothing
and are removed, rather than expanding to themselves.
p\bpa\bat\bts\bsu\bub\bb_\b_r\bre\bep\bpl\bla\bac\bce\bem\bme\ben\bnt\bt
If set, b\bba\bas\bsh\bh expands occurrences of &\b& in the replacement
- string of pattern substitution to the text matched by
- the pattern, as described under P\bPa\bar\bra\bam\bme\bet\bte\ber\br E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b). This option is enabled by default.
+ string of pattern substitution to the text matched by
+ the pattern, as described under P\bPa\bar\bra\bam\bme\bet\bte\ber\br E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in
+ _\bb_\ba_\bs_\bh(1). This option is enabled by default.
p\bpr\bro\bog\bgc\bco\bom\bmp\bp
If set, the programmable completion facilities (see P\bPr\bro\bo-\b-
- g\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) are enabled. This op-
+ g\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn in _\bb_\ba_\bs_\bh(1)) are enabled. This op-
tion is enabled by default.
p\bpr\bro\bog\bgc\bco\bom\bmp\bp_\b_a\bal\bli\bia\bas\bs
p\bpr\bro\bom\bmp\bpt\btv\bva\bar\brs\bs
If set, prompt strings undergo parameter expansion, com-
- mand substitution, arithmetic expansion, and quote re-
- moval after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b). This option is enabled by default.
+ mand substitution, arithmetic expansion, and quote re-
+ moval after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG in
+ _\bb_\ba_\bs_\bh(1). This option is enabled by default.
r\bre\bes\bst\btr\bri\bic\bct\bte\bed\bd_\b_s\bsh\bhe\bel\bll\bl
- The shell sets this option if it is started in re-
- stricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The
- value may not be changed. This is not reset when the
- startup files are executed, allowing the startup files
+ The shell sets this option if it is started in re-
+ stricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL in _\bb_\ba_\bs_\bh(1)). The
+ value may not be changed. This is not reset when the
+ startup files are executed, allowing the startup files
to discover whether or not a shell is restricted.
s\bsh\bhi\bif\bft\bt_\b_v\bve\ber\brb\bbo\bos\bse\be
- If set, the s\bsh\bhi\bif\bft\bt builtin prints an error message when
+ If set, the s\bsh\bhi\bif\bft\bt builtin prints an error message when
the shift count exceeds the number of positional parame-
ters.
s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh
If set, the .\b. (s\bso\bou\bur\brc\bce\be) builtin uses the value of P\bPA\bAT\bTH\bH to
- find the directory containing the file supplied as an
+ find the directory containing the file supplied as an
argument. This option is enabled by default.
v\bva\bar\brr\bre\bed\bdi\bir\br_\b_c\bcl\blo\bos\bse\be
- If set, the shell automatically closes file descriptors
- assigned using the _\b{_\bv_\ba_\br_\bn_\ba_\bm_\be_\b} redirection syntax (see R\bRE\bE-\b-
- D\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) instead of leaving them open when
- the command completes.
+ If set, the shell automatically closes file descriptors
+ assigned using the _\b{_\bv_\ba_\br_\bn_\ba_\bm_\be_\b} redirection syntax (see
+ R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh(1)) instead of leaving them open
+ when the command completes.
x\bxp\bpg\bg_\b_e\bec\bch\bho\bo
- If set, the e\bec\bch\bho\bo builtin expands backslash-escape se-
- quences by default. If the p\bpo\bos\bsi\bix\bx shell option is also
+ If set, the e\bec\bch\bho\bo builtin expands backslash-escape se-
+ quences by default. If the p\bpo\bos\bsi\bix\bx shell option is also
enabled, e\bec\bch\bho\bo does not interpret any options.
s\bsu\bus\bsp\bpe\ben\bnd\bd [-\b-f\bf]
- Suspend the execution of this shell until it receives a S\bSI\bIG\bGC\bCO\bON\bNT\bT
- signal. A login shell, or a shell without job control enabled,
- cannot be suspended; the -\b-f\bf option can be used to override this
- and force the suspension. The return status is 0 unless the
- shell is a login shell or job control is not enabled and -\b-f\bf is
+ Suspend the execution of this shell until it receives a S\bSI\bIG\bGC\bCO\bON\bNT\bT
+ signal. A login shell, or a shell without job control enabled,
+ cannot be suspended; the -\b-f\bf option can be used to override this
+ and force the suspension. The return status is 0 unless the
+ shell is a login shell or job control is not enabled and -\b-f\bf is
not supplied.
t\bte\bes\bst\bt _\be_\bx_\bp_\br
[\b[ _\be_\bx_\bp_\br ]\b]
Return a status of 0 (true) or 1 (false) depending on the evalu-
- ation of the conditional expression _\be_\bx_\bp_\br. Each operator and op-
- erand must be a separate argument. Expressions are composed of
- the primaries described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
+ ation of the conditional expression _\be_\bx_\bp_\br. Each operator and
+ operand must be a separate argument. Expressions are composed
+ of the primaries described in _\bb_\ba_\bs_\bh(1) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
S\bSI\bIO\bON\bNS\bS. t\bte\bes\bst\bt does not accept any options, nor does it accept and
ignore an argument of -\b--\b- as signifying the end of options.
- Expressions may be combined using the following operators,
- listed in decreasing order of precedence. The evaluation de-
- pends on the number of arguments; see below. Operator prece-
+ Expressions may be combined using the following operators,
+ listed in decreasing order of precedence. The evaluation de-
+ pends on the number of arguments; see below. Operator prece-
dence is used when there are five or more arguments.
!\b! _\be_\bx_\bp_\br True if _\be_\bx_\bp_\br is false.
(\b( _\be_\bx_\bp_\br )\b)
- Returns the value of _\be_\bx_\bp_\br. This may be used to override
+ Returns the value of _\be_\bx_\bp_\br. This may be used to override
the normal precedence of operators.
_\be_\bx_\bp_\br_\b1 -a\ba _\be_\bx_\bp_\br_\b2
True if both _\be_\bx_\bp_\br_\b1 and _\be_\bx_\bp_\br_\b2 are true.
If the first argument is !\b!, the expression is true if and
only if the second argument is null. If the first argu-
ment is one of the unary conditional operators listed in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS, the expression is
+ _\bb_\ba_\bs_\bh(1) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS, the expression is
true if the unary test is true. If the first argument is
not a valid unary conditional operator, the expression is
false.
3 arguments
The following conditions are applied in the order listed.
- If the second argument is one of the binary conditional
- operators listed in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
- S\bSI\bIO\bON\bNS\bS, the result of the expression is the result of the
- binary test using the first and third arguments as oper-
- ands. The -\b-a\ba and -\b-o\bo operators are considered binary op-
- erators when there are three arguments. If the first ar-
- gument is !\b!, the value is the negation of the two-argu-
+ If the second argument is one of the binary conditional
+ operators listed in _\bb_\ba_\bs_\bh(1) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
+ S\bSI\bIO\bON\bNS\bS, the result of the expression is the result of the
+ binary test using the first and third arguments as
+ operands. The -\b-a\ba and -\b-o\bo operators are considered binary
+ operators when there are three arguments. If the first
+ argument is !\b!, the value is the negation of the two-argu-
ment test using the second and third arguments. If the
first argument is exactly (\b( and the third argument is ex-
- actly )\b), the result is the one-argument test of the sec-
+ actly )\b), the result is the one-argument test of the sec-
ond argument. Otherwise, the expression is false.
4 arguments
The following conditions are applied in the order listed.
If the first argument is !\b!, the result is the negation of
- the three-argument expression composed of the remaining
- arguments. the two-argument test using the second and
- third arguments. If the first argument is exactly (\b( and
- the fourth argument is exactly )\b), the result is the two-
- argument test of the second and third arguments. Other-
+ the three-argument expression composed of the remaining
+ arguments. the two-argument test using the second and
+ third arguments. If the first argument is exactly (\b( and
+ the fourth argument is exactly )\b), the result is the two-
+ argument test of the second and third arguments. Other-
wise, the expression is parsed and evaluated according to
precedence using the rules listed above.
5 or more arguments
The expression is parsed and evaluated according to
precedence using the rules listed above.
- If the shell is not in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, when used with t\bte\bes\bst\bt or [\b[, the
- <\b< and >\b> operators sort lexicographically using ASCII ordering.
- When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, these operators sort using the
- current locale.
+ When the shell is in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, or if the expression is part of
+ the [\b[[\b[ command, the <\b< and >\b> operators sort using the current lo-
+ cale. If the shell is not in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, the t\bte\bes\bst\bt and [\b[ com-
+ mands sort lexicographically using ASCII ordering.
t\bti\bim\bme\bes\bs Print the accumulated user and system times for the shell and
for processes run from the shell. The return status is 0.
If no arguments are supplied, t\btr\bra\bap\bp displays the actions associ-
ated with each trapped signal as a set of t\btr\bra\bap\bp commands that can
- be reused as shell input to restore the current signal disposi-
- tions. If -\b-p\bp is given, and _\ba_\bc_\bt_\bi_\bo_\bn is not present, then t\btr\bra\bap\bp
- displays the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc or, if none
+ be reused as shell input to restore the current signal disposi-
+ tions. If -\b-p\bp is given, and _\ba_\bc_\bt_\bi_\bo_\bn is not present, then t\btr\bra\bap\bp
+ displays the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc or, if none
are supplied, for all trapped signals, as a set of t\btr\bra\bap\bp commands
that can be reused as shell input to restore the current signal
dispositions. The -\b-P\bP option behaves similarly, but displays
If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bEX\bXI\bIT\bT (0) the command _\ba_\bc_\bt_\bi_\bo_\bn is executed on exit
from the shell. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is D\bDE\bEB\bBU\bUG\bG, the command _\ba_\bc_\bt_\bi_\bo_\bn is
executed before every _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, _\bf_\bo_\br command, _\bc_\ba_\bs_\be command,
- _\bs_\be_\bl_\be_\bc_\bt command, (( arithmetic command, [[ conditional command,
+ _\bs_\be_\bl_\be_\bc_\bt command, (( arithmetic command, [[ conditional command,
arithmetic _\bf_\bo_\br command, and before the first command executes in
- a shell function (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). Refer to the
+ a shell function (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh(1)). Refer to the
description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin for de-
tails of its effect on the D\bDE\bEB\bBU\bUG\bG trap. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is R\bRE\bET\bTU\bUR\bRN\bN,
the command _\ba_\bc_\bt_\bi_\bo_\bn is executed each time a shell function or a
or a compound command returns a non-zero exit status, subject to
the following conditions. The E\bER\bRR\bR trap is not executed if the
failed command is part of the command list immediately following
- a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an _\bi_\bf statement,
+ a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an _\bi_\bf statement,
part of a command executed in a &\b&&\b& or |\b||\b| list except the command
following the final &\b&&\b& or |\b||\b|, any command in a pipeline but the
last, or if the command's return value is being inverted using
t\bty\byp\bpe\be [-\b-a\baf\bft\btp\bpP\bP] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
With no options, indicate how each _\bn_\ba_\bm_\be would be interpreted if
used as a command name. If the -\b-t\bt option is used, t\bty\byp\bpe\be prints a
- string which is one of _\ba_\bl_\bi_\ba_\bs, _\bk_\be_\by_\bw_\bo_\br_\bd, _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn, _\bb_\bu_\bi_\bl_\bt_\bi_\bn, or
- _\bf_\bi_\bl_\be if _\bn_\ba_\bm_\be is an alias, shell reserved word, function,
- builtin, or executable disk file, respectively. If the _\bn_\ba_\bm_\be is
- not found, then nothing is printed, and t\bty\byp\bpe\be returns a non-zero
- exit status. If the -\b-p\bp option is used, t\bty\byp\bpe\be either returns the
- name of the executable file that would be found by searching
- $\b$P\bPA\bAT\bTH\bH if _\bn_\ba_\bm_\be were specified as a command name, or nothing if
- ``type -t name'' would not return _\bf_\bi_\bl_\be. The -\b-P\bP option forces a
- P\bPA\bAT\bTH\bH search for each _\bn_\ba_\bm_\be, even if ``type -t name'' would not
- return _\bf_\bi_\bl_\be. If a command is hashed, -\b-p\bp and -\b-P\bP print the hashed
- value, which is not necessarily the file that appears first in
- P\bPA\bAT\bTH\bH. If the -\b-a\ba option is used, t\bty\byp\bpe\be prints all of the places
- that contain a command named _\bn_\ba_\bm_\be. This includes aliases, re-
- served words, functions, and builtins, but the path search op-
- tions (-\b-p\bp and -\b-P\bP) can be supplied to restrict the output to exe-
- cutable files. t\bty\byp\bpe\be does not consult the table of hashed com-
- mands when using -\b-a\ba with -\b-p\bp, and only performs a P\bPA\bAT\bTH\bH search for
- _\bn_\ba_\bm_\be. The -\b-f\bf option suppresses shell function lookup, as with
- the c\bco\bom\bmm\bma\ban\bnd\bd builtin. t\bty\byp\bpe\be returns true if all of the arguments
- are found, false if any are not found.
+ string which is one of _\ba_\bl_\bi_\ba_\bs, _\bk_\be_\by_\bw_\bo_\br_\bd, _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn, _\bb_\bu_\bi_\bl_\bt_\bi_\bn, or
+ _\bf_\bi_\bl_\be if _\bn_\ba_\bm_\be is an alias, shell reserved word, function,
+ builtin, or executable disk file, respectively. If the _\bn_\ba_\bm_\be is
+ not found, then nothing is printed, and t\bty\byp\bpe\be returns a non-zero
+ exit status. If the -\b-p\bp option is used, t\bty\byp\bpe\be either returns the
+ name of the executable file that would be found by searching
+ $\b$P\bPA\bAT\bTH\bH if _\bn_\ba_\bm_\be were specified as a command name, or nothing if
+ would not return _\bf_\bi_\bl_\be. The -\b-P\bP option forces a P\bPA\bAT\bTH\bH search for
+ each _\bn_\ba_\bm_\be, even if would not return _\bf_\bi_\bl_\be. If a command is
+ hashed, -\b-p\bp and -\b-P\bP print the hashed value, which is not necessar-
+ ily the file that appears first in P\bPA\bAT\bTH\bH. If the -\b-a\ba option is
+ used, t\bty\byp\bpe\be prints all of the places that contain a command named
+ _\bn_\ba_\bm_\be. This includes aliases, reserved words, functions, and
+ builtins, but the path search options (-\b-p\bp and -\b-P\bP) can be sup-
+ plied to restrict the output to executable files. t\bty\byp\bpe\be does not
+ consult the table of hashed commands when using -\b-a\ba with -\b-p\bp, and
+ only performs a P\bPA\bAT\bTH\bH search for _\bn_\ba_\bm_\be. The -\b-f\bf option suppresses
+ shell function lookup, as with the c\bco\bom\bmm\bma\ban\bnd\bd builtin. t\bty\byp\bpe\be re-
+ turns true if all of the arguments are found, false if any are
+ not found.
u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bS] -\b-a\ba
u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bS] [-\b-b\bbc\bcd\bde\bef\bfi\bik\bkl\blm\bmn\bnp\bpq\bqr\brs\bst\btu\buv\bvx\bxP\bPR\bRT\bT [_\bl_\bi_\bm_\bi_\bt]]
Provides control over the resources available to the shell and
to processes started by it, on systems that allow such control.
The -\b-H\bH and -\b-S\bS options specify that the hard or soft limit is set
- for the given resource. A hard limit cannot be increased by a
- non-root user once it is set; a soft limit may be increased up
- to the value of the hard limit. If neither -\b-H\bH nor -\b-S\bS is speci-
+ for the given resource. A hard limit cannot be increased by a
+ non-root user once it is set; a soft limit may be increased up
+ to the value of the hard limit. If neither -\b-H\bH nor -\b-S\bS is speci-
fied, both the soft and hard limits are set. The value of _\bl_\bi_\bm_\bi_\bt
can be a number in the unit specified for the resource or one of
the special values h\bha\bar\brd\bd, s\bso\bof\bft\bt, or u\bun\bnl\bli\bim\bmi\bit\bte\bed\bd, which stand for the
current hard limit, the current soft limit, and no limit, re-
spectively. If _\bl_\bi_\bm_\bi_\bt is omitted, the current value of the soft
limit of the resource is printed, unless the -\b-H\bH option is given.
- When more than one resource is specified, the limit name and
- unit, if appropriate, are printed before the value. Other op-
+ When more than one resource is specified, the limit name and
+ unit, if appropriate, are printed before the value. Other op-
tions are interpreted as follows:
-\b-a\ba All current limits are reported; no limits are set
-\b-b\bb The maximum socket buffer size
-\b-c\bc The maximum size of core files created
-\b-d\bd The maximum size of a process's data segment
- -\b-e\be The maximum scheduling priority ("nice")
- -\b-f\bf The maximum size of files written by the shell and its
+ -\b-e\be The maximum scheduling priority (
+ -\b-f\bf The maximum size of files written by the shell and its
children
-\b-i\bi The maximum number of pending signals
-\b-k\bk The maximum number of kqueues that may be allocated
-\b-l\bl The maximum size that may be locked into memory
- -\b-m\bm The maximum resident set size (many systems do not honor
+ -\b-m\bm The maximum resident set size (many systems do not honor
this limit)
-\b-n\bn The maximum number of open file descriptors (most systems
do not allow this value to be set)
u\bum\bma\bas\bsk\bk [-\b-p\bp] [-\b-S\bS] [_\bm_\bo_\bd_\be]
The user file-creation mask is set to _\bm_\bo_\bd_\be. If _\bm_\bo_\bd_\be begins with
- a digit, it is interpreted as an octal number; otherwise it is
- interpreted as a symbolic mode mask similar to that accepted by
- _\bc_\bh_\bm_\bo_\bd(1). If _\bm_\bo_\bd_\be is omitted, the current value of the mask is
- printed. The -\b-S\bS option causes the mask to be printed in sym-
- bolic form; the default output is an octal number. If the -\b-p\bp
+ a digit, it is interpreted as an octal number; otherwise it is
+ interpreted as a symbolic mode mask similar to that accepted by
+ _\bc_\bh_\bm_\bo_\bd(1). If _\bm_\bo_\bd_\be is omitted, the current value of the mask is
+ printed. The -\b-S\bS option causes the mask to be printed in sym-
+ bolic form; the default output is an octal number. If the -\b-p\bp
option is supplied, and _\bm_\bo_\bd_\be is omitted, the output is in a form
that may be reused as input. The return status is 0 if the mode
- was successfully changed or if no _\bm_\bo_\bd_\be argument was supplied,
+ was successfully changed or if no _\bm_\bo_\bd_\be argument was supplied,
and false otherwise.
u\bun\bna\bal\bli\bia\bas\bs [-a\ba] [_\bn_\ba_\bm_\be ...]
- Remove each _\bn_\ba_\bm_\be from the list of defined aliases. If -\b-a\ba is
- supplied, all alias definitions are removed. The return value
+ Remove each _\bn_\ba_\bm_\be from the list of defined aliases. If -\b-a\ba is
+ supplied, all alias definitions are removed. The return value
is true unless a supplied _\bn_\ba_\bm_\be is not a defined alias.
u\bun\bns\bse\bet\bt [-f\bfv\bv] [-n\bn] [_\bn_\ba_\bm_\be ...]
- For each _\bn_\ba_\bm_\be, remove the corresponding variable or function.
+ For each _\bn_\ba_\bm_\be, remove the corresponding variable or function.
If the -\b-v\bv option is given, each _\bn_\ba_\bm_\be refers to a shell variable,
and that variable is removed. Read-only variables may not be
unset. If -\b-f\bf is specified, each _\bn_\ba_\bm_\be refers to a shell func-
sequently reset. The exit status is true unless a _\bn_\ba_\bm_\be is read-
only or may not be unset.
- w\bwa\bai\bit\bt [-\b-f\bfn\bn] [-\b-p\bp _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bi_\bd _\b._\b._\b.]
+ w\bwa\bai\bit\bt [-\b-f\bfn\bn] [-\b-p\bp _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bi_\bd ...]
Wait for each specified child process and return its termination
- status. Each _\bi_\bd may be a process ID or a job specification; if
- a job spec is given, all processes in that job's pipeline are
- waited for. If _\bi_\bd is not given, w\bwa\bai\bit\bt waits for all running
- background jobs and the last-executed process substitution, if
+ status. Each _\bi_\bd may be a process ID or a job specification; if
+ a job spec is given, all processes in that job's pipeline are
+ waited for. If _\bi_\bd is not given, w\bwa\bai\bit\bt waits for all running
+ background jobs and the last-executed process substitution, if
its process id is the same as $\b$!\b!, and the return status is zero.
If the -\b-n\bn option is supplied, w\bwa\bai\bit\bt waits for a single job from
the list of _\bi_\bds or, if no _\bi_\bds are supplied, any job, to complete
- and returns its exit status. If none of the supplied arguments
+ and returns its exit status. If none of the supplied arguments
is a child of the shell, or if no arguments are supplied and the
shell has no unwaited-for children, the exit status is 127. If
the -\b-p\bp option is supplied, the process or job identifier of the
only when the -\b-n\bn option is supplied. Supplying the -\b-f\bf option,
when job control is enabled, forces w\bwa\bai\bit\bt to wait for _\bi_\bd to ter-
minate before returning its status, instead of returning when it
- changes status. If _\bi_\bd specifies a non-existent process or job,
- the return status is 127. If w\bwa\bai\bit\bt is interrupted by a signal,
- the return status will be greater than 128, as described under
- S\bSI\bIG\bGN\bNA\bAL\bLS\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b). Otherwise, the return status is the exit
+ changes status. If _\bi_\bd specifies a non-existent process or job,
+ the return status is 127. If w\bwa\bai\bit\bt is interrupted by a signal,
+ the return status will be greater than 128, as described under
+ S\bSI\bIG\bGN\bNA\bAL\bLS\bS in _\bb_\ba_\bs_\bh(1). Otherwise, the return status is the exit
status of the last process or job waited for.
S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE
- Bash-4.0 introduced the concept of a _\bs_\bh_\be_\bl_\bl _\bc_\bo_\bm_\bp_\ba_\bt_\bi_\bb_\bi_\bl_\bi_\bt_\by _\bl_\be_\bv_\be_\bl, speci-
- fied as a set of options to the shopt builtin ( c\bco\bom\bmp\bpa\bat\bt3\b31\b1, c\bco\bom\bmp\bpa\bat\bt3\b32\b2,
- c\bco\bom\bmp\bpa\bat\bt4\b40\b0, c\bco\bom\bmp\bpa\bat\bt4\b41\b1, and so on). There is only one current compatibil-
- ity level -- each option is mutually exclusive. The compatibility
- level is intended to allow users to select behavior from previous ver-
- sions that is incompatible with newer versions while they migrate
- scripts to use current features and behavior. It's intended to be a
- temporary solution.
-
- This section does not mention behavior that is standard for a particu-
- lar version (e.g., setting c\bco\bom\bmp\bpa\bat\bt3\b32\b2 means that quoting the rhs of the
- regexp matching operator quotes special regexp characters in the word,
+ Bash-4.0 introduced the concept of a _\bs_\bh_\be_\bl_\bl _\bc_\bo_\bm_\bp_\ba_\bt_\bi_\bb_\bi_\bl_\bi_\bt_\by _\bl_\be_\bv_\be_\bl, speci-
+ fied as a set of options to the shopt builtin (c\bco\bom\bmp\bpa\bat\bt3\b31\b1, c\bco\bom\bmp\bpa\bat\bt3\b32\b2, c\bco\bom\bm-\b-
+ p\bpa\bat\bt4\b40\b0, c\bco\bom\bmp\bpa\bat\bt4\b41\b1, and so on). There is only one current compatibility
+ level -- each option is mutually exclusive. The compatibility level is
+ intended to allow users to select behavior from previous versions that
+ is incompatible with newer versions while they migrate scripts to use
+ current features and behavior. It's intended to be a temporary solu-
+ tion.
+
+ This section does not mention behavior that is standard for a particu-
+ lar version (e.g., setting c\bco\bom\bmp\bpa\bat\bt3\b32\b2 means that quoting the rhs of the
+ regexp matching operator quotes special regexp characters in the word,
which is default behavior in bash-3.2 and subsequent versions).
- If a user enables, say, c\bco\bom\bmp\bpa\bat\bt3\b32\b2, it may affect the behavior of other
- compatibility levels up to and including the current compatibility
- level. The idea is that each compatibility level controls behavior
- that changed in that version of b\bba\bas\bsh\bh, but that behavior may have been
- present in earlier versions. For instance, the change to use locale-
- based comparisons with the [\b[[\b[ command came in bash-4.1, and earlier
+ If a user enables, say, c\bco\bom\bmp\bpa\bat\bt3\b32\b2, it may affect the behavior of other
+ compatibility levels up to and including the current compatibility
+ level. The idea is that each compatibility level controls behavior
+ that changed in that version of b\bba\bas\bsh\bh, but that behavior may have been
+ present in earlier versions. For instance, the change to use locale-
+ based comparisons with the [\b[[\b[ command came in bash-4.1, and earlier
versions used ASCII-based comparisons, so enabling c\bco\bom\bmp\bpa\bat\bt3\b32\b2 will enable
ASCII-based comparisons as well. That granularity may not be suffi-
cient for all uses, and as a result users should employ compatibility
Bash-4.3 introduced a new shell variable: B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT. The value as-
signed to this variable (a decimal version number like 4.2, or an inte-
- ger corresponding to the c\bco\bom\bmp\bpa\bat\bt_\bN_\bN option, like 42) determines the com-
+ ger corresponding to the c\bco\bom\bmp\bpa\bat\bt_\bN_\bN option, like 42) determines the com-
patibility level.
- Starting with bash-4.4, b\bba\bas\bsh\bh has begun deprecating older compatibility
- levels. Eventually, the options will be removed in favor of B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bM-\b-
+ Starting with bash-4.4, b\bba\bas\bsh\bh has begun deprecating older compatibility
+ levels. Eventually, the options will be removed in favor of B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bM-\b-
P\bPA\bAT\bT.
- Bash-5.0 was the final version for which there will be an individual
+ Bash-5.0 was the final version for which there will be an individual
shopt option for the previous version. Users should control the compat-
ibility level with B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT.
ator (=~) has no special effect
c\bco\bom\bmp\bpa\bat\bt3\b32\b2
- +\bo the <\b< and >\b> operators to the [\b[[\b[ command do not consider
+ +\bo the <\b< and >\b> operators to the [\b[[\b[ command do not consider
the current locale when comparing strings; they use ASCII
ordering.
c\bco\bom\bmp\bpa\bat\bt4\b42\b2
+\bo the replacement string in double-quoted pattern substitu-
- tion does not undergo quote removal, as it does in ver-
+ tion does not undergo quote removal, as it does in ver-
sions after bash-4.2
- +\bo in posix mode, single quotes are considered special when
- expanding the _\bw_\bo_\br_\bd portion of a double-quoted parameter
- expansion and can be used to quote a closing brace or
- other special character (this is part of POSIX interpre-
- tation 221); in later versions, single quotes are not
+ +\bo in posix mode, single quotes are considered special when
+ expanding the _\bw_\bo_\br_\bd portion of a double-quoted parameter
+ expansion and can be used to quote a closing brace or
+ other special character (this is part of POSIX interpre-
+ tation 221); in later versions, single quotes are not
special within double-quoted word expansions
c\bco\bom\bmp\bpa\bat\bt4\b43\b3
- +\bo the shell does not print a warning message if an attempt
- is made to use a quoted compound assignment as an argu-
- ment to declare (e.g., declare -a foo='(1 2)'). Later
+ +\bo the shell does not print a warning message if an attempt
+ is made to use a quoted compound assignment as an argu-
+ ment to declare (e.g., declare -a foo='(1 2)'). Later
versions warn that this usage is deprecated
- +\bo word expansion errors are considered non-fatal errors
- that cause the current command to fail, even in posix
- mode (the default behavior is to make them fatal errors
+ +\bo word expansion errors are considered non-fatal errors
+ that cause the current command to fail, even in posix
+ mode (the default behavior is to make them fatal errors
that cause the shell to exit)
- +\bo when executing a shell function, the loop state
+ +\bo when executing a shell function, the loop state
(while/until/etc.) is not reset, so b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be in
that function will break or continue loops in the calling
- context. Bash-4.4 and later reset the loop state to pre-
+ context. Bash-4.4 and later reset the loop state to pre-
vent this
c\bco\bom\bmp\bpa\bat\bt4\b44\b4
- +\bo the shell sets up the values used by B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV and
- B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC so they can expand to the shell's positional
+ +\bo the shell sets up the values used by B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV and
+ B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC so they can expand to the shell's positional
parameters even if extended debugging mode is not enabled
- +\bo a subshell inherits loops from its parent context, so
- b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be will cause the subshell to exit.
- Bash-5.0 and later reset the loop state to prevent the
+ +\bo a subshell inherits loops from its parent context, so
+ b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be will cause the subshell to exit.
+ Bash-5.0 and later reset the loop state to prevent the
exit
- +\bo variable assignments preceding builtins like e\bex\bxp\bpo\bor\brt\bt and
+ +\bo variable assignments preceding builtins like e\bex\bxp\bpo\bor\brt\bt and
r\bre\bea\bad\bdo\bon\bnl\bly\by that set attributes continue to affect variables
with the same name in the calling environment even if the
shell is not in posix mode
c\bco\bom\bmp\bpa\bat\bt5\b50\b0
- +\bo Bash-5.1 changed the way $\b$R\bRA\bAN\bND\bDO\bOM\bM is generated to intro-
+ +\bo Bash-5.1 changed the way $\b$R\bRA\bAN\bND\bDO\bOM\bM is generated to intro-
duce slightly more randomness. If the shell compatibility
level is set to 50 or lower, it reverts to the method
from bash-5.0 and previous versions, so seeding the ran-
scripts @\b@ and *\b* differently depending on whether the ar-
ray is indexed or associative, and differently than in
previous versions.
- +\bo arithmetic commands ( ((...)) ) and the expressions in an
+ +\bo arithmetic commands ( (\b((\b(...)\b))\b) ) and the expressions in an
arithmetic for statement can be expanded more than once
- +\bo expressions used as arguments to arithmetic operators in
+ +\bo expressions used as arguments to arithmetic operators in
the [\b[[\b[ conditional command can be expanded more than once
- +\bo the expressions in substring parameter brace expansion
+ +\bo the expressions in substring parameter brace expansion
can be expanded more than once
- +\bo the expressions in the $(( ... )) word expansion can be
- expanded more than once
+ +\bo the expressions in the $\b$(\b((\b(...)\b))\b) word expansion can be ex-
+ panded more than once
+\bo arithmetic expressions used as indexed array subscripts
can be expanded more than once
- +\bo t\bte\bes\bst\bt -\b-v\bv, when given an argument of A\bA[\b[@\b@]\b], where A\bAP\bP i\bis\bs a\ban\bn
- e\bex\bxi\bis\bst\bti\bin\bng\bg a\bas\bss\bso\boc\bci\bia\bat\bti\biv\bve\be a\bar\brr\bra\bay\by,\b, w\bwi\bil\bll\bl r\bre\bet\btu\bur\brn\bn t\btr\bru\bue\be i\bif\bf t\bth\bhe\be a\bar\brr\bra\bay\by
- h\bha\bas\bs a\ban\bny\by s\bse\bet\bt e\bel\ble\bem\bme\ben\bnt\bts\bs.\b. B\bBa\bas\bsh\bh-\b-5\b5.\b.2\b2 w\bwi\bil\bll\bl l\blo\boo\bok\bk f\bfo\bor\br a\ban\bnd\bd r\bre\bep\bpo\bor\brt\bt
- o\bon\bn a\ba k\bke\bey\by n\bna\bam\bme\bed\bd @\b@.\b.
- +\b+\bo\bo the ${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br[\b[:\b:]\b]=\b=_\bv_\ba_\bl_\bu_\be} word expansion will return
- _\bv_\ba_\bl_\bu_\be, before any variable-specific transformations have
+ +\bo t\bte\bes\bst\bt -\b-v\bv, when given an argument of A\bA[\b[@\b@]\b], where A\bA is an
+ existing associative array, will return true if the array
+ has any set elements. Bash-5.2 will look for and report
+ on a key named @\b@.
+ +\bo the ${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br[\b[:\b:]\b]=\b=_\bv_\ba_\bl_\bu_\be} word expansion will return
+ _\bv_\ba_\bl_\bu_\be, before any variable-specific transformations have
been performed (e.g., converting to lowercase). Bash-5.2
will return the final value assigned to the variable.
+\bo Parsing command substitutions will behave as if extended
globbing (see the description of the s\bsh\bho\bop\bpt\bt builtin above)
- is enabled, so that parsing a command substitution con-
+ is enabled, so that parsing a command substitution con-
taining an extglob pattern (say, as part of a shell func-
tion) will not fail. This assumes the intent is to en-
able extglob before the command is executed and word ex-
S\bSE\bEE\bE A\bAL\bLS\bSO\bO
bash(1), sh(1)
-
-
-GNU Bash 5.2 2023 January 27 BASH_BUILTINS(1)
+GNU Bash 5.2 2023 January 27 _\bB_\bA_\bS_\bH_\b__\bB_\bU_\bI_\bL_\bT_\bI_\bN_\bS(1)
.\" Case Western Reserve University
.\" chet.ramey@case.edu
.\"
-.\" Last Change: Fri Jan 19 11:53:57 EST 2024
+.\" Last Change: Mon Feb 5 14:37:12 EST 2024
.\"
-.TH HISTORY 3 "2024 January 19" "GNU History 8.3"
+.TH HISTORY 3 "2024 February 5" "GNU History 8.3"
.\"
.\" File Name macro. This used to be `.PN', for Path Name,
.\" but Sun doesn't seem to like that very much.
..
.de Q
.ie \n(.g \(lq\\$1\(rq\\$2
-.el \{
+.el \{\
. if t ``\\$1''\\$2
. if n "\\$1"\\$2
.\}
Many programs read input from the user a line at a time. The GNU
History library is able to keep track of those lines, associate arbitrary
data with each line, and utilize information from previous lines in
-composing new ones.
+composing new ones.
.PP
.SH "HISTORY EXPANSION"
The history library supports a history expansion feature that
Various \fImodifiers\fP are available to manipulate the selected words.
The line is broken into words in the same fashion as \fBbash\fP
does when reading input,
-so that several words that would otherwise be separated
+so that several words that would otherwise be separated
are considered one word when surrounded by quotes (see the
description of \fBhistory_tokenize()\fP below).
.PP
.IR n .
.TP
.B !!
-Refer to the previous command. This is a synonym for `!\-1'.
+Refer to the previous command. This is a synonym for
+.Q !\-1 .
.TP
.B !\fIstring\fR
Refer to the most recent command
zeroth word if there is only one word in the line.
.TP
.B %
-The first word matched by the most recent `?\fIstring\fR?' search,
+The first word matched by the most recent
+.Q ?\fIstring\fR?
+search,
if the search string begins with a character that is part of a word.
.TP
.I x\fB\-\fPy
-A range of words; `\-\fIy\fR' abbreviates `0\-\fIy\fR'.
+A range of words;
+.Q \-\fIy\fR
+abbreviates
+.Q 0\-\fIy\fR .
.TP
.B *
-All of the words but the zeroth. This is a synonym
-for `\fI1\-$\fP'. It is not an error to use
+All of the words but the zeroth.
+This is a synonym for
+.Q \fI1\-$\fP .
+It is not an error to use
.B *
if there is just one
word in the event; the empty string is returned in that case.
previous command is used as the event.
.SS Modifiers
After the optional word designator, there may appear a sequence of
-one or more of the following modifiers, each preceded by a `:'.
+one or more of the following modifiers, each preceded by a
+.Q : .
These modify, or edit, the word or words selected from the history event.
.PP
.PD 0
Repeat the previous substitution.
.TP
.B g
-Cause changes to be applied over the entire event line. This is
-used in conjunction with `\fB:s\fP' (e.g., `\fB:gs/\fIold\fP/\fInew\fP/\fR')
-or `\fB:&\fP'. If used with
-`\fB:s\fP', any delimiter can be used
-in place of /, and the final delimiter is optional
+Cause changes to be applied over the entire event line.
+This is used in conjunction with
+.Q \fB:s\fP
+(e.g.,
+.Q \fB:gs/\fIold\fP/\fInew\fP/\fR )
+or
+.Q \fB:&\fP .
+If used with
+.Q \fB:s\fP ,
+any delimiter can be used in place of /,
+and the final delimiter is optional
if it is the last character of the event line.
An \fBa\fP may be used as a synonym for \fBg\fP.
.TP
.B G
-Apply the following `\fBs\fP' or `\fB&\fP' modifier once to each word
-in the event line.
+Apply the following
+.Q \fBs\fP
+ or
+.Q \fB&\fP
+modifier once to each word in the event line.
.PD
.SH "PROGRAMMING WITH HISTORY FUNCTIONS"
This section describes how to use the History library in other programs.
\fIstring\fP. If \fIdirection\fP is less than 0, then the search is
through previous entries, otherwise through subsequent entries.
If \fIstring\fP is found, then the
-current history index is set to that entry, and the return value is 0.
-Otherwise, nothing is changed, and a -1 is returned.
+current history index is set to that entry, and the return value is 0.
+Otherwise, nothing is changed, and a -1 is returned.
.Fn3 int history_search_pos "const char *string" "int direction" "int pos"
Search for \fIstring\fP in the history list, starting at \fIpos\fP, an
.Vb "char *" history_word_delimiters
The characters that separate tokens for \fBhistory_tokenize()\fP.
-The default value is \fB"\ \et\en()<>;&|"\fP.
+The default value is \fB\(dq\ \et\en()<>;&|\(dq\fP.
.Vb "char *" history_no_expand_chars
The list of characters which inhibit history expansion if found immediately
expansion character for additional purposes.
By default, this variable is set to \fBNULL\fP.
.SH FILES
-.PD 0
+.PD 0
.TP
.FN \(ti/.history
Default filename for reading and writing saved history
.\" Case Western Reserve University
.\" chet.ramey@case.edu
.\"
-.\" Last Change: Thu Jan 18 11:05:44 EST 2024
+.\" Last Change: Mon Feb 5 10:50:56 EST 2024
.\"
-.TH READLINE 3 "2024 January 18" "GNU Readline 8.3"
+.TH READLINE 3 "2024 February 5" "GNU Readline 8.3"
.\"
.\" File Name macro. This used to be `.PN', for Path Name,
.\" but Sun doesn't seem to like that very much.
..
.de Q
.ie \n(.g \(lq\\$1\(rq\\$2
-.el \{
+.el \{\
. if t ``\\$1''\\$2
. if n "\\$1"\\$2
.\}
will read a line from the terminal
and return it, using
.B prompt
-as a prompt. If
+as a prompt. If
.B prompt
is \fBNULL\fP or the empty string, no prompt is issued.
The line returned is allocated with
is the name of a key spelled out in English. For example:
.PP
.RS
-Control\-u: universal\-argument
-.br
-Meta\-Rubout: backward\-kill\-word
-.br
-Control\-o: "> output"
+.EX
+.nf
+Control-u: universal\-argument
+Meta-Rubout: backward\-kill\-word
+Control-o: \(dq> output\(dq
+.fi
+.EE
.RE
.LP
In the above example,
.Q "> output"
into the line).
.PP
-In the second form, \fB"keyseq"\fP:\^\fIfunction\-name\fP or \fImacro\fP,
+In the second form,
+\fB\(dqkeyseq\(dq\fP:\^\fIfunction\-name\fP or \fImacro\fP,
.B keyseq
differs from
.B keyname
are not recognized.
.PP
.RS
-"\eC\-u": universal\-argument
-.br
-"\eC\-x\eC\-r": re\-read\-init\-file
-.br
-"\ee[11\(ti": "Function Key 1"
+.EX
+.nf
+\(dq\eC\-u\(dq: universal\-argument
+\(dq\eC\-x\eC\-r\(dq: re\-read\-init\-file
+\(dq\ee[11\(ti\(dq: \(dqFunction Key 1\(dq
+.fi
+.EE
.RE
.PP
In this example,
.B \e\e
backslash
.TP
-.B \e"
-literal ", a double quote
+.B \e\(dq
+literal \(dq, a double quote
.TP
-.B \e'
-literal ', a single quote
+.B \e\(aq
+literal \(aq, a single quote
.RE
.PD
.PP
is assumed to be a function name.
In the macro body, the backslash escapes described above are expanded.
Backslash will quote any other character in the macro text,
-including " and '.
+including \(dq and \(aq.
.PP
.B Bash
allows the current readline key bindings to be displayed or modified
.B Off
(without regard to case).
Unrecognized variable names are ignored.
-When a variable value is read, empty or null values, "on" (case-insensitive),
-and "1" are equivalent to \fBOn\fP. All other values are equivalent to
+When readline reads a variable value, empty or null values,
+.Q "on"
+(case-insensitive), and
+.Q 1
+are equivalent to \fBOn\fP.
+All other values are equivalent to
\fBOff\fP.
The variables and their default values are:
.PP
The default value is the string that puts the terminal in standout mode,
as obtained from the terminal's terminfo description.
A sample value might be
-.Q "\ee[01;33m" .
+.Q \ee[01;33m .
.TP
.B active\-region\-end\-color
A string variable that
The default value is the string that restores the terminal from standout mode,
as obtained from the terminal's terminfo description.
A sample value might be
-.Q "\ee[0m" .
+.Q \ee[0m .
.TP
.B bell\-style (audible)
Controls what happens when readline wants to ring the terminal bell.
If set to \fBaudible\fP, readline attempts to ring the terminal's bell.
.TP
.B bind\-tty\-special\-chars (On)
-If set to \fBOn\fP (the default), readline attempts to bind the control
-characters that are
-treated specially by the kernel's terminal driver to their
-readline equivalents.
+If set to \fBOn\fP (the default), readline attempts to bind
+the control characters that are treated specially by the kernel's
+terminal driver to their readline equivalents.
These override the default readline bindings described here.
Type
.Q "stty -a"
colors to indicate their file type.
The color definitions are taken from the value of the \fBLS_COLORS\fP
environment variable.
+.\" Tucking multiple macro calls into a paragraph tag requires some
+.\" finesse. We require `\c`, and while the single-font macros don't
+.\" honor input trap continuation, the font alternation macros do.
.TP
-.B comment\-begin (``#'')
-The string that is inserted in \fBvi\fP mode when the
+.BR comment\-begin\ (\c
+.Q \fB#\fP \fB)\fP
+The string that is inserted when the
.B insert\-comment
command is executed.
This command is bound to
screen width.
A value of 0 will cause matches to be displayed one per line.
The default value is \-1.
-.TP
+.TP
.B completion\-ignore\-case (Off)
If set to \fBOn\fP, readline performs filename matching and completion
in a case\-insensitive fashion.
escape character (in effect, using escape as the \fImeta prefix\fP).
The default is \fIOn\fP, but readline will set it to \fIOff\fP if the
locale contains eight-bit characters.
-This variable is dependent on the \fBLC_CTYPE\fP locale category, and
+This variable is dependent on the \fBLC_CTYPE\fP locale category, and
may change if the locale is changed.
.TP
.B disable\-completion (Off)
-If set to \fBOn\fP, readline will inhibit word completion. Completion
+If set to \fBOn\fP, readline will inhibit word completion. Completion
characters will be inserted into the line as if they had been
mapped to \fBself-insert\fP.
.TP
.BR vi .
.TP
.B emacs\-mode\-string (@)
-If the \fIshow\-mode\-in\-prompt\fP variable is enabled,
+If the \fIshow\-mode\-in\-prompt\fP variable is enabled,
this string is displayed immediately before the last line of the primary
prompt when emacs editing mode is active. The value is expanded like a
key binding, so the standard set of meta- and control prefixes and
backslash escape sequences is available.
Use the \e1 and \e2 escapes to begin and end sequences of
-non-printing characters, which can be used to embed a terminal control
+non-printing characters, which can be used to embed a terminal control
sequence into the mode string.
.TP
.B enable\-active\-region (On)
attempts word completion.
.TP
.B history\-preserve\-point (Off)
-If set to \fBOn\fP, the history code attempts to place point at the
-same location on each history line retrieved with \fBprevious-history\fP
+If set to \fBOn\fP, the history code attempts to place point at the
+same location on each history line retrieved with \fBprevious-history\fP
or \fBnext-history\fP.
.TP
.B history\-size (unset)
regardless of what the terminal claims it can support. The name
.B meta\-flag
is a synonym for this variable.
-The default is \fIOff\fP, but readline will set it to \fIOn\fP if the
+The default is \fIOff\fP, but readline will set it to \fIOn\fP if the
locale contains eight-bit characters.
-This variable is dependent on the \fBLC_CTYPE\fP locale category, and
+This variable is dependent on the \fBLC_CTYPE\fP locale category, and
may change if the locale is changed.
.TP
-.B isearch\-terminators (``C\-[ C\-J'')
+.BR isearch\-terminators\ (\c
+.Q \fBC\-[C\-J\fP \fB)\fP
The string of characters that should terminate an incremental
search without subsequently executing the character as a command.
If this variable has not been given a value, the characters
.B keyseq\-timeout (500)
Specifies the duration \fIreadline\fP will wait for a character when reading an
ambiguous key sequence (one that can form a complete key sequence using
-the input read so far, or can take additional input to complete a longer
+the input read so far, or can take additional input to complete a longer
key sequence).
If no input is received within the timeout, \fIreadline\fP will use the shorter
but complete key sequence.
\fBmark\-directories\fP).
.TP
.B match\-hidden\-files (On)
-This variable, when set to \fBOn\fP, causes readline to match files whose
-names begin with a `.' (hidden files) when performing filename
-completion.
-If set to \fBOff\fP, the leading `.' must be
-supplied by the user in the filename to be completed.
+This variable, when set to \fBOn\fP, forces readline to match files whose
+names begin with a
+.Q .
+(hidden files) when performing filename completion.
+If set to \fBOff\fP, the user must include the leading
+.Q .
+in the filename to be completed.
.TP
.B menu\-complete\-display\-prefix (Off)
If set to \fBOn\fP, menu completion displays the common prefix of the
This alters the default behavior of the completion functions in
a fashion similar to \fBshow\-all\-if\-ambiguous\fP.
If set to
-.BR On ,
+.BR On ,
words which have more than one possible completion without any
-possible partial completion (the possible completions don't share
+possible partial completion (the possible completions don't share
a common prefix) cause the matches to be listed immediately instead
of ringing the bell.
.TP
following the cursor are not duplicated.
.TP
.B vi\-cmd\-mode\-string ((cmd))
-If the \fIshow\-mode\-in\-prompt\fP variable is enabled,
+If the \fIshow\-mode\-in\-prompt\fP variable is enabled,
this string is displayed immediately before the last line of the primary
prompt when vi editing mode is active and in command mode.
The value is expanded like a
sequence into the mode string.
.TP
.B vi\-ins\-mode\-string ((ins))
-If the \fIshow\-mode\-in\-prompt\fP variable is enabled,
+If the \fIshow\-mode\-in\-prompt\fP variable is enabled,
this string is displayed immediately before the last line of the primary
-prompt when vi editing mode is active and in insertion mode.
+prompt when vi editing mode is active and in insertion mode.
The value is expanded like a
-key binding, so the standard set of meta- and control prefixes and
+key binding, so the standard set of meta- and control prefixes and
backslash escape sequences is available.
Use the \e1 and \e2 escapes to begin and end sequences of
-non-printing characters, which can be used to embed a terminal control
+non-printing characters, which can be used to embed a terminal control
sequence into the mode string.
.TP
.B visible\-stats (Off)
-If set to \fBOn\fP, a character denoting a file's type as reported
+If set to \fBOn\fP, a character denoting a file's type as reported
by \fIstat\fP(2) is appended to the filename when listing possible
completions.
.PD
compilation features of the C preprocessor which allows key
bindings and variable settings to be performed as the result
of tests. There are four parser directives used.
-.IP \fB$if\fP
+.TP
+.B $if
The
.B $if
construct allows bindings to be made based on the
extends to the end of the line;
unless otherwise noted, no characters are required to isolate it.
.RS
-.IP \fBmode\fP
+.TP
+.B mode
The \fBmode=\fP form of the \fB$if\fP directive is used to test
whether readline is in emacs or vi mode.
This may be used in conjunction
with the \fBset keymap\fP command, for instance, to set bindings in
the \fIemacs-standard\fP and \fIemacs-ctlx\fP keymaps only if
readline is starting out in emacs mode.
-.IP \fBterm\fP
+.TP
+.B term
The \fBterm=\fP form may be used to include terminal-specific
key bindings, perhaps to bind the key sequences output by the
terminal's function keys. The word on the right side of the
and
.IR sun\-cmd ,
for instance.
-.IP \fBversion\fP
+.TP
+.B version
The \fBversion\fP test may be used to perform comparisons against
specific readline versions.
The \fBversion\fP expands to the current readline version.
is assumed to be \fB0\fP.
The operator may be separated from the string \fBversion\fP
and from the version number argument by whitespace.
-.IP \fBapplication\fP
-The \fBapplication\fP construct is used to include
-application-specific settings. Each program using the readline
+.TP
+.I application
+The \fIapplication\fP construct is used to include
+application-specific settings.
+Each program using the readline
library sets the \fIapplication name\fP, and an initialization
file can test for a particular value.
This could be used to bind key sequences to functions useful for
key sequence that quotes the current or previous word in \fBbash\fP:
.PP
.RS
+.EX
.nf
\fB$if\fP Bash
# Quote the current or previous word
-"\eC-xq": "\eeb\e"\eef\e""
+\(dq\eC-xq\(dq: \(dq\eeb\e\(dq\eef\e\(dq\(dq
\fB$endif\fP
.fi
+.EE
.RE
-.IP \fIvariable\fP
+.TP
+.I variable
The \fIvariable\fP construct provides simple equality tests for readline
variables and values.
The permitted comparison operators are \fI=\fP, \fI==\fP, and \fI!=\fP.
Both string and boolean variables may be tested. Boolean variables must be
tested against the values \fIon\fP and \fIoff\fP.
.RE
-.IP \fB$endif\fP
+.TP
+.B $endif
This command, as seen in the previous example, terminates an
\fB$if\fP command.
-.IP \fB$else\fP
+.TP
+.B $else
Commands in this branch of the \fB$if\fP directive are executed if
the test fails.
-.IP \fB$include\fP
+.TP
+.B $include
This directive takes a single filename as an argument and reads commands
and bindings from that file. For example, the following directive
would read \fI/etc/inputrc\fP:
.PP
.nf
\fB$include\fP \^ \fI/etc/inputrc\fP
-.fi
+.fi
.RE
.SH SEARCHING
Readline provides commands for searching through the command history
Without an argument, move back to the first entry in the history list.
.TP
.B reverse\-search\-history (C\-r)
-Search backward starting at the current line and moving `up' through
-the history as necessary. This is an incremental search.
+Search backward starting at the current line and moving
+.Q up
+through the history as necessary.
+This is an incremental search.
.TP
.B forward\-search\-history (C\-s)
-Search forward starting at the current line and moving `down' through
-the history as necessary. This is an incremental search.
+Search forward starting at the current line and moving
+.Q down
+through the history as necessary.
+This is an incremental search.
.TP
.B non\-incremental\-reverse\-search\-history (M\-p)
Search backward through the history starting at the current line
Delete the character behind the cursor. When given a numeric argument,
save the deleted text on the kill ring.
.TP
-.B forward\-backward\-delete\-char
+.B forward\-backward\-delete\-char
Delete the character under the cursor, unless the cursor is at the
end of the line, in which case the character behind the cursor is
deleted.
.B tab\-insert (M-TAB)
Insert a tab character.
.TP
-.B self\-insert (a,\ b,\ A,\ 1,\ !,\ ...)
+.B "self\-insert (a, b, A, 1, !, \fR.\|.\|.\fP)"
Insert the character typed.
.TP
.B transpose\-chars (C\-t)
.SS Numeric Arguments
.PD 0
.TP
-.B digit\-argument (M\-0, M\-1, ..., M\-\-)
+.B digit\-argument (M\-0, M\-1, \fR.\|.\|.\fP, M\-\-)
Add this digit to the argument already accumulating, or start a new
argument. M\-\- starts a negative argument.
.TP
(subject to the setting of \fBbell\-style\fP)
and the original text is restored.
An argument of \fIn\fP moves \fIn\fP positions forward in the list
-of matches; a negative argument may be used to move backward
+of matches; a negative argument may be used to move backward
through the list.
This command is intended to be bound to \fBTAB\fP, but is unbound
by default.
ring the terminal's bell (subject to the setting of
.BR bell\-style ).
.TP
-.B do\-lowercase\-version (M\-A, M\-B, M\-\fIx\fP, ...)
+.B do\-lowercase\-version (M\-A, M\-B, M\-\fIx\fP, \fR.\|.\|.\fP)
If the metafied character \fIx\fP is uppercase, run the command
that is bound to the corresponding metafied lowercase character.
The behavior is undefined if \fIx\fP is already lowercase.
.B comment\-begin
variable is inserted at the beginning of the current line.
If a numeric argument is supplied, this command acts as a toggle: if
-the characters at the beginning of the line do not match the value
-of \fBcomment\-begin\fP, the value is inserted, otherwise
+the characters at the beginning of the line do not match the value
+of \fBcomment\-begin\fP, the value is inserted, otherwise
the characters in \fBcomment-begin\fP are deleted from the beginning of
the line.
In either case, the line is accepted as if a newline had been typed.
@end example
Variable names and values, where appropriate, are recognized without regard
-to case. Unrecognized variable names are ignored.
+to case.
+Unrecognized variable names are ignored.
Boolean variables (those that can be set to on or off) are set to on if
-the value is null or empty, @var{on} (case-insensitive), or 1. Any other
-value results in the variable being set to off.
+the value is null or empty, @var{on} (case-insensitive), or 1.
+Any other value results in the variable being set to off.
@ifset BashFeatures
The @w{@code{bind -V}} command lists the current Readline variable names
@item match-hidden-files
@vindex match-hidden-files
-This variable, when set to @samp{on}, causes Readline to match files whose
+This variable, when set to @samp{on}, forces Readline to match files whose
names begin with a @samp{.} (hidden files) when performing filename
completion.
-If set to @samp{off}, the leading @samp{.} must be
-supplied by the user in the filename to be completed.
+If set to @samp{off}, the user must include the leading @samp{.}
+in the filename to be completed.
This variable is @samp{on} by default.
@item menu-complete-display-prefix
projects / thirdparty / bash.git / commitdiff
