_\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.
+ 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 _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn is evaluated according to the rules described
- below under A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN. If the value of the expres-
- sion is non-zero, the return status is 0; otherwise the return
+ The _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn is evaluated according to the rules described
+ below under A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN. If the value of the expres-
+ sion is non-zero, the return status is 0; otherwise the return
status is 1. This is exactly equivalent to l\ble\bet\bt "\b"_\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn"\b".
[\b[[\b[ _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn ]\b]]\b]
- Return a status of 0 or 1 depending on the evaluation of the
- conditional expression _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn. Expressions are composed of
- 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.
- Word splitting and pathname expansion are not performed on the
- words between the [\b[[\b[ and ]\b]]\b]; tilde expansion, parameter and
- variable expansion, arithmetic expansion, command substitution,
- process substitution, and quote removal are performed. Condi-
+ Return a status of 0 or 1 depending on the evaluation of the
+ conditional expression _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn. Expressions are composed of
+ 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.
+ Word splitting and pathname expansion are not performed on the
+ words between the [\b[[\b[ and ]\b]]\b]; tilde expansion, parameter and
+ variable expansion, arithmetic expansion, command substitution,
+ process substitution, and quote removal are performed. Condi-
tional operators such as -\b-f\bf must be unquoted to be recognized as
primaries.
- When the =\b==\b= and !\b!=\b= operators are used, the string to the right
+ 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 P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg. If the shell
- option n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh 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 pat-
+ the rules described below under P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg. If the shell
+ option n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh 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 pat-
tern, and 1 otherwise. Any part of the pattern may be quoted to
force it 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
- right of the operator is considered an extended regular expres-
+ 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 an extended regular expres-
sion and matched accordingly (as in _\br_\be_\bg_\be_\bx(3)). The return value
is 0 if the string matches the pattern, and 1 otherwise. If the
- regular expression is syntactically incorrect, the conditional
+ regular expression is syntactically incorrect, the conditional
expression's return value is 2. If the shell option n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh
is enabled, the match is performed without regard to the case of
alphabetic characters. Substrings matched by parenthesized
- subexpressions within the regular expression are saved in the
- array variable B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH. The element of B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH with
+ subexpressions within the regular expression are saved in the
+ array variable B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH. The element of B\bBA\bAS\bSH\bH_\b_R\bRE\bEM\bMA\bAT\bTC\bCH\bH with
index 0 is the portion of the string matching the entire regular
- expression. 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 subexpres-
+ expression. 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 subexpres-
sion.
- 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.
True if either _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn_\b1 or _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn_\b2 is true.
The &\b&&\b& and |\b||\b| operators do not evaluate _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn_\b2 if the value
- of _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn_\b1 is sufficient to determine the return value of
+ of _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn_\b1 is sufficient to determine the return value of
the entire conditional expression.
f\bfo\bor\br _\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. The variable _\bn_\ba_\bm_\be is set to each element of this list in
- turn, and _\bl_\bi_\bs_\bt is executed each time. If the i\bin\bn _\bw_\bo_\br_\bd is omit-
- ted, the f\bfo\bor\br command executes _\bl_\bi_\bs_\bt once for each positional
+ turn, and _\bl_\bi_\bs_\bt is executed each time. If the i\bin\bn _\bw_\bo_\br_\bd is omit-
+ ted, the f\bfo\bor\br command executes _\bl_\bi_\bs_\bt once for each positional
parameter that is set (see P\bPA\bAR\bRA\bAM\bME\bET\bTE\bER\bRS\bS below). The return status
- is the exit status of the last command that executes. If the
+ is the exit status of the last command that executes. If the
expansion of the items following i\bin\bn results in an empty list, no
commands are executed, and the return status is 0.
f\bfo\bor\br (( _\be_\bx_\bp_\br_\b1 ; _\be_\bx_\bp_\br_\b2 ; _\be_\bx_\bp_\br_\b3 )) ; d\bdo\bo _\bl_\bi_\bs_\bt ; d\bdo\bon\bne\be
First, the arithmetic expression _\be_\bx_\bp_\br_\b1 is evaluated according to
- the rules described below under A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN. The
- arithmetic expression _\be_\bx_\bp_\br_\b2 is then evaluated repeatedly until
- it evaluates to zero. Each time _\be_\bx_\bp_\br_\b2 evaluates to a non-zero
- value, _\bl_\bi_\bs_\bt is executed and the arithmetic expression _\be_\bx_\bp_\br_\b3 is
- evaluated. If any expression is omitted, it behaves as if it
+ the rules described below under A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN. The
+ arithmetic expression _\be_\bx_\bp_\br_\b2 is then evaluated repeatedly until
+ it evaluates to zero. Each time _\be_\bx_\bp_\br_\b2 evaluates to a non-zero
+ value, _\bl_\bi_\bs_\bt is executed and the arithmetic expression _\be_\bx_\bp_\br_\b3 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 _\bl_\bi_\bs_\bt that is executed, or false if any of the expres-
sions is invalid.
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. 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).
- The P\bPS\bS3\b3 prompt is then displayed and a line read from the stan-
- dard 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-
+ items. 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).
+ The P\bPS\bS3\b3 prompt is then displayed and a line read from the stan-
+ dard 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 command completes. 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 executed after each
+ 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 executed 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,
+ 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 same matching rules as for path-
- name expansion (see P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn below). The _\bw_\bo_\br_\bd is
- expanded using tilde expansion, parameter and variable expan-
- sion, arithmetic substitution, command substitution, process
- substitution and quote removal. Each _\bp_\ba_\bt_\bt_\be_\br_\bn examined is
+ name expansion (see P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn below). The _\bw_\bo_\br_\bd is
expanded using tilde expansion, parameter and variable expan-
+ sion, arithmetic substitution, command substitution, process
+ substitution and quote removal. Each _\bp_\ba_\bt_\bt_\be_\br_\bn examined is
+ expanded using tilde expansion, parameter and variable expan-
sion, arithmetic substitution, command substitution, and process
- substitution. If the shell option n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh is enabled, the
- match is performed without regard to the case of alphabetic
- characters. When a match is found, the corresponding _\bl_\bi_\bs_\bt is
- executed. After the first match, no subsequent matches are
+ substitution. If the shell option n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh is enabled, the
+ match is performed without regard to the case of alphabetic
+ characters. When a match is found, the corresponding _\bl_\bi_\bs_\bt is
+ executed. After the first match, no subsequent matches are
attempted. The exit status is zero if no pattern matches. Oth-
- erwise, it is the exit status of the last command executed in
+ erwise, it is the exit status of the last command executed in
_\bl_\bi_\bs_\bt.
i\bif\bf _\bl_\bi_\bs_\bt; t\bth\bhe\ben\bn _\bl_\bi_\bs_\bt_\b; [ e\bel\bli\bif\bf _\bl_\bi_\bs_\bt; t\bth\bhe\ben\bn _\bl_\bi_\bs_\bt; ] ... [ e\bel\bls\bse\be _\bl_\bi_\bs_\bt; ] f\bfi\bi
- The i\bif\bf _\bl_\bi_\bs_\bt is executed. If its exit status is zero, the t\bth\bhe\ben\bn
- _\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
+ The i\bif\bf _\bl_\bi_\bs_\bt is executed. If its exit status is zero, the t\bth\bhe\ben\bn
+ _\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.
w\bwh\bhi\bil\ble\be _\bl_\bi_\bs_\bt; d\bdo\bo _\bl_\bi_\bs_\bt; d\bdo\bon\bne\be
u\bun\bnt\bti\bil\bl _\bl_\bi_\bs_\bt; d\bdo\bo _\bl_\bi_\bs_\bt; d\bdo\bon\bne\be
- The w\bwh\bhi\bil\ble\be command continuously executes the d\bdo\bo _\bl_\bi_\bs_\bt as long as
- the last command in _\bl_\bi_\bs_\bt returns an exit status of zero. The
+ The w\bwh\bhi\bil\ble\be command continuously executes the d\bdo\bo _\bl_\bi_\bs_\bt as long as
+ the last command in _\bl_\bi_\bs_\bt 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, except that the
- test is negated; the d\bdo\bo _\bl_\bi_\bs_\bt is executed as long as the last
+ test is negated; the d\bdo\bo _\bl_\bi_\bs_\bt is executed as long as the last
command in _\bl_\bi_\bs_\bt 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 last
+ of the w\bwh\bhi\bil\ble\be and u\bun\bnt\bti\bil\bl commands is the exit status of the last
d\bdo\bo _\bl_\bi_\bs_\bt command executed, or zero if none was executed.
S\bSh\bhe\bel\bll\bl F\bFu\bun\bnc\bct\bti\bio\bon\bn D\bDe\bef\bfi\bin\bni\bit\bti\bio\bon\bns\bs
- A shell function is an object that is called like a simple command and
- executes a compound command with a new set of positional parameters.
+ A shell function is an object that is called like a simple command and
+ executes a compound command with a new set of positional parameters.
Shell functions are declared as follows:
[ f\bfu\bun\bnc\bct\bti\bio\bon\bn ] _\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 _\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
- 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. _\bc_\bo_\bm_\b-
+ This defines a function named _\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
+ 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. _\bc_\bo_\bm_\b-
_\bp_\bo_\bu_\bn_\bd_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed whenever _\bn_\ba_\bm_\be is specified as the name
- of a simple command. Any redirections (see R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN below)
- specified when a function is defined are performed when the
- function is executed. The exit status of a function definition
+ of a simple command. Any redirections (see R\bRE\bED\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN below)
+ specified 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
+ 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
In a non-interactive shell, or an interactive shell in which the i\bin\bnt\bte\ber\br-\b-
- a\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs option to the s\bsh\bho\bop\bpt\bt builtin is enabled (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 word beginning with #\b# causes that word and
- all remaining characters on that line to be ignored. An interactive
- shell without the i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs option enabled does not allow
+ a\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs option to the s\bsh\bho\bop\bpt\bt builtin is enabled (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 word beginning with #\b# causes that word and
+ all remaining characters on that line to be ignored. An interactive
+ shell without the i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs option enabled does not allow
comments. The i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs option is on by default in interac-
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.
- Each of the _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br_\bs listed above under D\bDE\bEF\bFI\bIN\bNI\bIT\bTI\bIO\bON\bNS\bS has special
+ Each of the _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br_\bs listed above under D\bDE\bEF\bFI\bIN\bNI\bIT\bTI\bIO\bON\bNS\bS 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 H\bHI\bIS\bS-\b-
+ When the command history expansion facilities are being used (see H\bHI\bIS\bS-\b-
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
- itself quoted, the \\b\<newline> is treated as a line continuation (that
+ <newline>. If a \\b\<newline> pair appears, and the backslash is not
+ itself 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!. The characters $\b$ and `\b` retain
- their special meaning within double quotes. The backslash retains its
- special meaning 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
+ 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!. The characters $\b$ and `\b` retain
+ their special meaning within double quotes. The backslash retains its
+ special meaning 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
+ 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).
Words of the form $\b$'_\bs_\bt_\br_\bi_\bn_\bg' are treated specially. The word expands to
- _\bs_\bt_\br_\bi_\bn_\bg, with backslash-escaped characters replaced as specified by the
- ANSI C standard. Backslash escape sequences, if present, are decoded
+ _\bs_\bt_\br_\bi_\bn_\bg, with backslash-escaped characters replaced as specified by the
+ ANSI C standard. Backslash escape sequences, if present, are decoded
as follows:
\\b\a\ba alert (bell)
\\b\b\bb backspace
\\b\v\bv vertical tab
\\b\\\b\ backslash
\\b\'\b' single quote
- \\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)
\\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 ($\b$) will cause the
- string to be translated according to the current locale. If the cur-
- rent locale is C\bC or P\bPO\bOS\bSI\bIX\bX, the dollar sign is ignored. If the string
+ A double-quoted string preceded by a dollar sign ($\b$) will cause the
+ string to be translated according to the current locale. If the cur-
+ rent locale is C\bC or P\bPO\bOS\bSI\bIX\bX, the dollar sign is ignored. If the string
is translated and replaced, the replacement is double-quoted.
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-
+ 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
- _\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).
+ 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
+ _\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 $((...)) expansion
- is not used (see A\bAr\bri\bit\bth\bhm\bme\bet\bti\bic\bc E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn below). Word splitting is not
- performed, with the exception of "\b"$\b$@\b@"\b" as explained below under S\bSp\bpe\bec\bci\bia\bal\bl
- P\bPa\bar\bra\bam\bme\bet\bte\ber\brs\bs. Pathname expansion is not performed. Assignment state-
- ments may also appear as arguments to the a\bal\bli\bia\bas\bs, d\bde\bec\bcl\bla\bar\bre\be, t\bty\byp\bpe\bes\bse\bet\bt,
+ is not used (see A\bAr\bri\bit\bth\bhm\bme\bet\bti\bic\bc E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn below). Word splitting is not
+ performed, with the exception of "\b"$\b$@\b@"\b" as explained below under S\bSp\bpe\bec\bci\bia\bal\bl
+ P\bPa\bar\bra\bam\bme\bet\bte\ber\brs\bs. Pathname expansion is not performed. Assignment state-
+ ments may also appear 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.
- 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. When += is applied to a vari-
- able for which the integer attribute has been set, _\bv_\ba_\bl_\bu_\be is evaluated
- as an arithmetic expression and added to the variable's current value,
+ able for which the integer attribute has been set, _\bv_\ba_\bl_\bu_\be is evaluated
+ as an arithmetic expression and added to the variable's current value,
which is also evaluated. When += is applied to an array variable using
- compound assignment (see A\bAr\brr\bra\bay\bys\bs below), the variable's value is not
+ compound assignment (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. When applied
- to a string-valued variable, _\bv_\ba_\bl_\bu_\be is expanded and appended to the
+ beginning at one greater than the array's maximum index. When applied
+ to a string-valued variable, _\bv_\ba_\bl_\bu_\be is expanded and appended to the
variable's value.
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
- with assignment statements. The positional parameters are temporarily
+ 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
+ with assignment statements. The positional parameters are temporarily
replaced when a shell function is executed (see F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS below).
- When a positional parameter consisting of more than a single digit is
+ When a positional parameter consisting of more than a single digit is
expanded, it must be enclosed in braces (see E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN below).
S\bSp\bpe\bec\bci\bia\bal\bl P\bPa\bar\bra\bam\bme\bet\bte\ber\brs\bs
- The shell treats several parameters specially. These parameters may
+ 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 occurs within double quotes, it expands to a sin-
+ *\b* Expands to the positional parameters, starting from one. When
+ the expansion occurs within double quotes, it expands to a sin-
gle word with the value of each parameter separated by the first
character of the I\bIF\bFS\bS special variable. That is, "$\b$*\b*" is equiva-
lent to "$\b$1\b1_\bc$\b$2\b2_\bc.\b..\b..\b.", where _\bc is the first character of the value
- of the I\bIF\bFS\bS variable. If I\bIF\bFS\bS is unset, the parameters are sepa-
- rated by spaces. If I\bIF\bFS\bS is null, the parameters are joined
+ of the I\bIF\bFS\bS variable. If I\bIF\bFS\bS is unset, the parameters are sepa-
+ rated by spaces. If I\bIF\bFS\bS is null, the parameters are joined
without intervening separators.
- @\b@ Expands to the positional parameters, starting from one. When
+ @\b@ Expands to the positional parameters, starting from one. When
the expansion occurs within double quotes, each parameter
expands to a separate word. That is, "$\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
+ "$\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).
#\b# Expands to the number of positional parameters in decimal.
- ?\b? Expands to the status of the most recently executed foreground
+ ?\b? Expands to the status of the most recently executed foreground
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
+ -\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
itself (such as the -\b-i\bi option).
- $\b$ Expands to the process ID of the shell. In a () subshell, it
- expands to the process ID of the current shell, not the sub-
+ $\b$ Expands to the process ID of the shell. In a () subshell, it
+ expands to the process ID of the current shell, not the sub-
shell.
- !\b! Expands to the process ID of the most recently executed back-
+ !\b! Expands to the process ID of the most recently executed back-
ground (asynchronous) command.
- 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
- the string to be executed, if one is present. Otherwise, it is
- set to the file name used to invoke b\bba\bas\bsh\bh, as given by argument
+ 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
+ the string to be executed, if one is present. Otherwise, it is
+ set to the file name used to invoke b\bba\bas\bsh\bh, as given by argument
zero.
- _\b_ At shell startup, set to the absolute pathname used to invoke
- the shell or shell script being executed as passed in the envi-
- ronment or argument list. Subsequently, expands to the last
- argument to the previous command, after expansion. Also set to
- the full pathname used to invoke each command executed and
+ _\b_ At shell startup, set to the absolute pathname used to invoke
+ the shell or shell script being executed as passed in the envi-
+ ronment or argument list. Subsequently, expands to the last
+ argument to the previous command, after expansion. Also set to
+ the full pathname used to invoke each command executed and
placed in the environment exported to that command. When check-
- ing mail, this parameter holds the name of the mail file cur-
+ ing mail, this parameter holds the name of the mail file cur-
rently being checked.
S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs
The following variables are set by the shell:
- B\bBA\bAS\bSH\bH Expands to the full file name used to invoke this instance of
+ B\bBA\bAS\bSH\bH Expands to the full file name used to invoke this instance of
b\bba\bas\bsh\bh.
B\bBA\bAS\bSH\bHP\bPI\bID\bD
- Expands to the process id of the current bash process. This
- differs from $\b$$\b$ under certain circumstances, such as subshells
+ Expands to the process id of the current bash process. This
+ differs from $\b$$\b$ under certain circumstances, such as subshells
that do not require bash to be re-initialized.
B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC
- An array variable whose values are the number of parameters in
+ 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 .\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
+ 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\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 bash execution call stack. The final parameter of the last
- subroutine call is at the top of the stack; the first parameter
+ 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
+ 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
below)
B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD
- The command currently being executed or about to be executed,
+ 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
+ in which case it is the command executing at the time of the
trap.
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 corresponding to each member of F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE.
- $\b${\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 where
- $\b${\b{F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE[\b[_\b$_\bi_\bf_\bP]\b]}\b} _\bw_\ba_\bs _\bc_\ba_\bl_\bl_\be_\bd_\b. _\bT_\bh_\be _\bc_\bo_\br_\br_\be_\bs_\bp_\bo_\bn_\bd_\bi_\bn_\bg _\bs_\bo_\bu_\br_\bc_\be _\bf_\bi_\bl_\be
- _\bn_\ba_\bm_\be _\bi_\bs $\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi]\b]}\b}.\b. U\bUs\bse\be L\bLI\bIN\bNE\bEN\bNO\bO t\bto\bo o\bob\bbt\bta\bai\bin\bn t\bth\bhe\be c\bcu\bur\brr\bre\ben\bnt\bt
+ An array variable whose members are the line numbers in source
+ files corresponding to each member of F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE.
+ $\b${\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 where
+ $\b${\b{F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE[\b[_\b$_\bi_\bf_\bP]\b]}\b} _\bw_\ba_\bs _\bc_\ba_\bl_\bl_\be_\bd_\b. _\bT_\bh_\be _\bc_\bo_\br_\br_\be_\bs_\bp_\bo_\bn_\bd_\bi_\bn_\bg _\bs_\bo_\bu_\br_\bc_\be _\bf_\bi_\bl_\be
+ _\bn_\ba_\bm_\be _\bi_\bs $\b${\b{B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE[\b[_\b$_\bi]\b]}\b}.\b. U\bUs\bse\be L\bLI\bIN\bNE\bEN\bNO\bO t\bto\bo o\bob\bbt\bta\bai\bin\bn t\bth\bhe\be c\bcu\bur\brr\bre\ben\bnt\bt
l\bli\bin\bne\be n\bnu\bum\bmb\bbe\ber\br.\b.
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
- expression. The element with index _\bn is the portion of the
+ 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
+ expression. The element with index _\bn is the portion of the
string matching the _\bnth parenthesized subexpression. This vari-
able is read-only.
B\bBA\bAS\bSH\bH_\b_S\bSO\bOU\bUR\bRC\bCE\bE
- An array variable whose members are the source filenames corre-
+ An array variable whose members are the source filenames corre-
sponding to the elements in the F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE array variable.
B\bBA\bAS\bSH\bH_\b_S\bSU\bUB\bBS\bSH\bHE\bEL\bLL\bL
- Incremented by one each time a subshell or subshell environment
+ Incremented by one each time a subshell or subshell environment
is spawned. The initial value is 0.
B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO
A readonly array variable whose members hold version information
- for this instance of b\bba\bas\bsh\bh. The values assigned to the array
+ for this instance of b\bba\bas\bsh\bh. The values assigned to the array
members are as follows:
- B\bBA\bAS\bSH\bH_\b_V\bVE\bER\bRS\bSI\bIN\bNF\bFO\bO[\b[0]\b] The major version number (the _\br_\be_\bl_\be_\ba_\bs_\be).
- 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[0]\b] The major version number (the _\br_\be_\bl_\be_\ba_\bs_\be).
+ 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[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
+ Expands to a string describing the version of this instance of
b\bba\bas\bsh\bh.
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
+ 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
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 pro-
- grammable 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
+ The current command line. This variable is available only in
+ shell functions and external commands invoked by the pro-
+ grammable 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
+ 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 pro-
- grammable 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
+ 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 pro-
+ grammable 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 pro-
- grammable 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
+ 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 pro-
+ grammable 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 Readline 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 Readline 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 words are split on
- shell metacharacters as the shell parser would separate them.
- This variable is available only in shell functions invoked by
+ An array variable (see A\bAr\brr\bra\bay\bys\bs below) consisting of the individ-
+ ual words in the current command line. The words are split on
+ shell metacharacters as the shell parser would separate them.
+ This variable is available only in shell functions 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\be-\b-
t\bti\bio\bon\bn below).
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
+ 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
- unset, it loses its special properties, even if it is subse-
+ able will not change the current directory. If D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK is
+ unset, it loses its special properties, even if it is subse-
quently 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 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 and return an error status. If F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE is unset, it
- loses its special properties, even if it is subsequently reset.
-
- 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
- and return an error status. If G\bGR\bRO\bOU\bUP\bPS\bS is unset, it loses its
+ tom-most element 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 and return an error status. If F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE is unset, it
+ loses its special properties, even if it is subsequently reset.
+
+ 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
+ and return an error status. If G\bGR\bRO\bOU\bUP\bPS\bS is unset, it loses its
special properties, even if it is subsequently reset.
H\bHI\bIS\bST\bTC\bCM\bMD\bD
The history number, or index in the history list, of the current
- command. If H\bHI\bIS\bST\bTC\bCM\bMD\bD is unset, it loses its special properties,
+ command. If H\bHI\bIS\bST\bTC\bCM\bMD\bD 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
- Automatically set to a string that fully describes the system
- type on which b\bba\bas\bsh\bh is executing, in the standard GNU _\bc_\bp_\bu_\b-_\bc_\bo_\bm_\b-
+ Automatically set to a string that fully describes the system
+ type on which b\bba\bas\bsh\bh is executing, in the standard GNU _\bc_\bp_\bu_\b-_\bc_\bo_\bm_\b-
_\bp_\ba_\bn_\by_\b-_\bs_\by_\bs_\bt_\be_\bm format. The default is system-dependent.
O\bOL\bLD\bDP\bPW\bWD\bD The previous working directory as set by the c\bcd\bd command.
- O\bOP\bPT\bTA\bAR\bRG\bG The value of the last option argument processed by the g\bge\bet\bto\bop\bpt\bts\bs
+ O\bOP\bPT\bTA\bAR\bRG\bG The value of the last option argument processed 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\bTI\bIN\bND\bD The index of the next argument to be processed by the g\bge\bet\bto\bop\bpt\bts\bs
+ O\bOP\bPT\bTI\bIN\bND\bD The index of the next argument to be processed 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\bOS\bST\bTY\bYP\bPE\bE Automatically set to a string that describes the operating sys-
- tem on which b\bba\bas\bsh\bh is executing. The default is system-depen-
+ O\bOS\bST\bTY\bYP\bPE\bE Automatically set to a string that describes the operating sys-
+ tem on which b\bba\bas\bsh\bh is executing. The default is system-depen-
dent.
P\bPI\bIP\bPE\bES\bST\bTA\bAT\bTU\bUS\bS
- An array variable (see A\bAr\brr\bra\bay\bys\bs below) containing a list of exit
- status values from the processes in the most-recently-executed
+ An array variable (see A\bAr\brr\bra\bay\bys\bs below) 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\bPP\bPI\bID\bD The process ID of the shell's parent. This variable is read-
+ P\bPP\bPI\bID\bD The process ID of the shell's parent. This variable is read-
only.
P\bPW\bWD\bD The current working directory as set by the c\bcd\bd command.
R\bRA\bAN\bND\bDO\bOM\bM Each time this parameter is referenced, a random integer between
0 and 32767 is generated. The sequence of random numbers may be
initialized by assigning a value to R\bRA\bAN\bND\bDO\bOM\bM. If R\bRA\bAN\bND\bDO\bOM\bM is unset,
- it loses its special properties, even if it is subsequently
+ it loses its special properties, even if it is subsequently
reset.
- 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, the number of seconds
- since shell invocation is returned. If a value is assigned to
- S\bSE\bEC\bCO\bON\bND\bDS\bS, the value returned upon subsequent references is the
- number of seconds since the assignment plus the value assigned.
+ Each time this parameter is referenced, the number of seconds
+ since shell invocation is returned. If a value is assigned to
+ S\bSE\bEC\bCO\bON\bND\bDS\bS, the value returned upon subsequent references is the
+ number of seconds since the assignment plus the value assigned.
If S\bSE\bEC\bCO\bON\bND\bDS\bS is unset, it loses its special properties, even if it
is subsequently reset.
S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS
- 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
+ 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.
U\bUI\bID\bD Expands to the user ID of the current user, initialized at shell
startup. This variable is readonly.
- The following variables are used by the shell. In some cases, b\bba\bas\bsh\bh
+ The following variables are used by the shell. In some cases, b\bba\bas\bsh\bh
assigns a default value to a variable; these cases are noted below.
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 file name.
+ subjected to parameter expansion, command substitution, and
+ arithmetic expansion before being interpreted as a file name.
P\bPA\bAT\bTH\bH is not used to search for the resultant file name.
- 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
- directories specified by the c\bcd\bd command. A sample value is
+ 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
+ directories specified by the c\bcd\bd command. A sample value is
".:~:/usr".
C\bCO\bOL\bLU\bUM\bMN\bNS\bS
- Used by the s\bse\bel\ble\bec\bct\bt builtin command to determine the terminal
- width when printing selection lists. Automatically set upon
+ Used by the s\bse\bel\ble\bec\bct\bt builtin command to determine the terminal
+ width when printing selection lists. Automatically set upon
receipt of a SIGWINCH.
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-
+ 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).
- 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.
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
+ 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:~".
G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE
A colon-separated list of patterns defining the set of filenames
to be ignored by pathname expansion. If a filename matched by a
- pathname expansion pattern also matches one of the patterns in
+ pathname expansion pattern also matches one of the patterns in
G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE, it is removed from the list of matches.
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_\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
- to be removed from the history list before that line is saved.
- 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
+ to be removed from the history list before that line is saved.
+ 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-
- T\bTO\bOR\bRY\bY below). The default value is _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bh_\bi_\bs_\bt_\bo_\br_\by. If unset,
- the command history is not saved when an interactive shell
+ T\bTO\bOR\bRY\bY below). The default value is _\b~_\b/_\b._\bb_\ba_\bs_\bh_\b__\bh_\bi_\bs_\bt_\bo_\br_\by. If unset,
+ the command history is not saved when an interactive 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, by removing the oldest entries, to contain
- no more than that number of lines. The default value is 500.
+ this variable is assigned a value, the history file is trun-
+ cated, if necessary, by removing the oldest entries, to contain
+ no more than that number of lines. The default value is 500.
The history file is also truncated to this size after writing it
when an interactive shell exits.
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
- anchored at the beginning of the line and must match the com-
- plete 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\bN-\b-
- T\bTR\bRO\bOL\bL are applied. In addition to the normal shell pattern
+ 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 com-
+ plete 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\bN-\b-
+ T\bTR\bRO\bOL\bL are applied. In addition to the normal shell pattern
matching characters, `&\b&' matches the previous history line. `&\b&'
- may be escaped using a backslash; the backslash is removed
+ 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 H\bHI\bIS\bST\bTI\bIG\bGN\bNO\bOR\bRE\bE.
H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE
- The number of commands to remember in the command history (see
+ The number of commands to remember in the command history (see
H\bHI\bIS\bST\bTO\bOR\bRY\bY below). The default value is 500.
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
- file so they may be preserved across shell sessions. This uses
- the history comment character to distinguish timestamps from
+ 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
+ file so they may be preserved across shell sessions. This uses
+ the history comment character to distinguish timestamps from
other history lines.
H\bHO\bOM\bME\bE The home directory of the current user; the default argument for
the c\bcd\bd builtin command. The value of this variable is also used
when performing tilde expansion.
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
+ 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
- attempted 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
+ 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, 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, 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 completions. When H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE is unset, the
+ possible hostname completions. 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
- after expansion and to split lines into words with the r\bre\bea\bad\bd
+ 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
+ after expansion and to split lines into words with the r\bre\bea\bad\bd
builtin command. The default value is ``<space><tab><new-
line>''.
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
+ The filename for the r\bre\bea\bad\bdl\bli\bin\bne\be startup file, overriding the
default of _\b~_\b/_\b._\bi_\bn_\bp_\bu_\bt_\br_\bc (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE below).
- 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
+ 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
sequences 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\bLI\bIN\bNE\bES\bS Used by the s\bse\bel\ble\bec\bct\bt builtin command to determine the column
- length for printing selection lists. Automatically set upon
+ L\bLI\bIN\bNE\bES\bS Used by the s\bse\bel\ble\bec\bct\bt builtin command to determine the column
+ length for printing selection lists. Automatically set upon
receipt of a SIGWINCH.
- M\bMA\bAI\bIL\bL If this parameter is set to a file name and the M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH vari-
+ M\bMA\bAI\bIL\bL If this parameter is set to a file name and the M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH vari-
able is not set, b\bba\bas\bsh\bh informs the user of the arrival of mail in
the specified file.
M\bMA\bAI\bIL\bLC\bCH\bHE\bEC\bCK\bK
- Specifies how often (in seconds) b\bba\bas\bsh\bh checks for mail. 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
+ Specifies how often (in seconds) b\bba\bas\bsh\bh checks for mail. 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.
M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH
- A colon-separated list of file names to be checked for mail.
+ A colon-separated list of file names to be checked for mail.
The message to be printed when mail arrives in a particular file
- may be specified by separating the file name from the message
+ may be specified by separating the file name 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?"$_ has
mail!"'
- B\bBa\bas\bsh\bh supplies a default value for this variable, but the loca-
- tion of the user mail files that it uses is system dependent
+ B\bBa\bas\bsh\bh supplies a default value for this variable, but the loca-
+ tion of the user mail files that it uses is system dependent
(e.g., /var/mail/$\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
+ 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/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin''.
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
+ 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.
P\bPR\bRO\bOM\bMP\bPT\bT_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD
If set, the value is executed as a command prior to issuing each
primary prompt.
- 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
+ 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$ ''.
- P\bPS\bS2\b2 The value of this parameter is expanded as with P\bPS\bS1\b1 and used as
+ 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> ''.
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
- value is printed before each command b\bba\bas\bsh\bh displays during an
- execution trace. The first character of P\bPS\bS4\b4 is replicated mul-
- tiple times, as necessary, to indicate multiple levels of indi-
+ 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
+ execution trace. The first character of P\bPS\bS4\b4 is replicated mul-
+ tiple times, as necessary, to indicate multiple levels of indi-
rection. The default is ``+\b+ ''.
S\bSH\bHE\bEL\bLL\bL The full pathname to the shell is kept in this environment vari-
- able. If it is not set when the shell starts, b\bba\bas\bsh\bh assigns to
+ able. 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\bEF\bFO\bOR\bRM\bMA\bAT\bT
- The value of this parameter is used as a format string specify-
- ing how the timing information for pipelines prefixed with the
- 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
+ The value of this parameter is used as a format string specify-
+ ing how the timing information for pipelines prefixed with the
+ 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.
%\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]S\bS The number of CPU seconds spent in system mode.
%\b%P\bP The CPU percentage, computed as (%U + %S) / %R.
- The optional _\bp is a digit specifying the _\bp_\br_\be_\bc_\bi_\bs_\bi_\bo_\bn, the number
+ 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 three places
- after the decimal point may be specified; values of _\bp greater
- than 3 are changed to 3. If _\bp is not specified, the value 3 is
+ after the decimal point may be specified; values of _\bp greater
+ than 3 are changed to 3. 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%3\b3l\blS\bS'\b'. If the value is null, no
- timing information is displayed. A trailing newline is added
+ 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%3\b3l\blS\bS'\b'. If the value is null, no
+ timing information is displayed. A trailing newline 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
+ T\bTM\bMO\bOU\bUT\bT If set to a value greater than zero, T\bTM\bMO\bOU\bUT\bT is treated as the
default 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
- interpreted as the number of seconds to wait for input after
- issuing the primary prompt. B\bBa\bas\bsh\bh terminates after waiting for
+ coming from a terminal. In an interactive shell, the value is
+ interpreted as the number of seconds to wait for input after
+ issuing the primary prompt. B\bBa\bas\bsh\bh terminates after waiting for
that number of seconds if 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
- job control. If this variable is set, single word simple com-
+ job control. If this variable is set, single word simple com-
mands without redirections are treated as candidates for resump-
tion of an existing stopped job. There is no ambiguity allowed;
- if there is more than one job beginning with the string typed,
- the job most recently accessed is selected. The _\bn_\ba_\bm_\be of a
- stopped job, in this context, is the command line used to start
- it. If set to the value _\be_\bx_\ba_\bc_\bt, the string supplied must match
- the name of a stopped job exactly; if set to _\bs_\bu_\bb_\bs_\bt_\br_\bi_\bn_\bg, the
- string supplied needs to match a substring of the name of a
- stopped job. The _\bs_\bu_\bb_\bs_\bt_\br_\bi_\bn_\bg value provides functionality analo-
- gous to the %\b%?\b? job identifier (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL below). If set
- to any other value, the supplied string must be a prefix of a
+ if there is more than one job beginning with the string typed,
+ the job most recently accessed is selected. The _\bn_\ba_\bm_\be of a
+ stopped job, in this context, is the command line used to start
+ it. If set to the value _\be_\bx_\ba_\bc_\bt, the string supplied must match
+ the name of a stopped job exactly; if set to _\bs_\bu_\bb_\bs_\bt_\br_\bi_\bn_\bg, the
+ string supplied needs to match a substring of the name of a
+ stopped job. The _\bs_\bu_\bb_\bs_\bt_\br_\bi_\bn_\bg value provides functionality analo-
+ gous to the %\b%?\b? job identifier (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL below). 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
%\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
- 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. The default is
- `^\b^'. The optional third character is the character which indi-
- cates that the remainder of the line is a comment when found as
- the first character of a word, normally `#\b#'. The history com-
+ 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
+ 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. The default is
+ `^\b^'. The optional third character is the character which indi-
+ cates that the remainder of the line is a comment when found as
+ the first character of a word, normally `#\b#'. The history com-
ment character causes history substitution to be skipped for the
- remaining words on the line. It does not necessarily cause 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 array variables. Any variable may be
+ B\bBa\bas\bsh\bh provides one-dimensional array variables. Any variable may be
used as an 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 contiguously. Arrays are indexed
+ There is no maximum limit on the size of an array, nor any requirement
+ that members be indexed or assigned contiguously. Arrays are indexed
using integers and are zero-based.
- An 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 greater than or
- equal to zero. To explicitly declare an array, use d\bde\bec\bcl\bla\bar\bre\be -\b-a\ba _\bn_\ba_\bm_\be
+ An 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 greater than or
+ equal to zero. To explicitly declare an 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\bMM\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_\bs_\bc_\br_\bi_\bp_\bt is ignored. Attributes may be specified for an
array variable using the d\bde\bec\bcl\bla\bar\bre\be and r\bre\bea\bad\bdo\bon\bnl\bly\by builtins. Each attribute
applies to all members of an array.
- Arrays are assigned to using compound assignments of the form
- _\bn_\ba_\bm_\be=(\b(value_\b1 ... value_\bn)\b), where each _\bv_\ba_\bl_\bu_\be is of the form [_\bs_\bu_\bb_\b-
+ Arrays are assigned to using compound assignments of the form
+ _\bn_\ba_\bm_\be=(\b(value_\b1 ... value_\bn)\b), where each _\bv_\ba_\bl_\bu_\be is of the form [_\bs_\bu_\bb_\b-
_\bs_\bc_\br_\bi_\bp_\bt]=_\bs_\bt_\br_\bi_\bn_\bg. Only _\bs_\bt_\br_\bi_\bn_\bg is required. If the optional brackets and
- subscript are 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. This syntax is also accepted by
- the d\bde\bec\bcl\bla\bar\bre\be builtin. Individual array elements may be assigned to
+ subscript are 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. 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 introduced above.
- Any element of an array may be referenced using ${_\bn_\ba_\bm_\be[_\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt]}.
+ 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. These
- subscripts differ only when the word appears within double quotes. 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. These
+ subscripts 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
+ 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
- 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 *\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_\b-
- _\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 ele-
- ments in the array. Referencing an array variable without a subscript
+ 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
+ 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 *\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_\b-
+ _\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 ele-
+ ments in the array. Referencing an array variable without a subscript
is equivalent to referencing element zero.
- 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]
- destroys the array element at index _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt. Care must be taken to
+ 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]
+ destroys the array element at index _\bs_\bu_\bb_\bs_\bc_\br_\bi_\bp_\bt. Care must be taken to
avoid unwanted side effects caused by filename generation. u\bun\bns\bse\bet\bt _\bn_\ba_\bm_\be,
- where _\bn_\ba_\bm_\be is an array, or 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*
+ where _\bn_\ba_\bm_\be is an array, or 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@, removes the entire array.
- 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 array. 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
+ 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 array. 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-
+ 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.
- The order of expansions is: brace expansion, tilde expansion, parame-
- ter, variable and arithmetic expansion and command substitution (done
+ The order of expansions is: brace expansion, tilde expansion, parame-
+ ter, variable and arithmetic expansion and command substitution (done
in a left-to-right fashion), word splitting, and pathname expansion.
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.
Only brace expansion, word splitting, and pathname expansion can change
- 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
+ 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{_\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,
+ 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 sequence expression takes the form {\b{_\bx.\b..\b._\by}\b}, where _\bx and _\by are either
+ A sequence expression takes the form {\b{_\bx.\b..\b._\by}\b}, where _\bx and _\by are either
integers or single characters. When integers are supplied, the expres-
- sion expands to each number between _\bx and _\by, inclusive. When charac-
- ters are supplied, the expression expands to each character lexico-
+ sion expands to each number between _\bx and _\by, inclusive. When charac-
+ ters are supplied, the expression expands to each character lexico-
graphically between _\bx and _\by, inclusive. Note that both _\bx and _\by must be
of the same type.
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
- closing braces, and at least one unquoted comma or a valid sequence
- expression. Any incorrectly formed brace expansion is left unchanged.
+ A correctly-formed brace expansion must contain unquoted opening and
+ closing braces, and at least one unquoted comma or a valid sequence
+ expression. 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-
+ part of a brace expression. To avoid conflicts with parameter expan-
sion, the string $\b${\b{ is not considered eligible for brace expansion.
This construct is typically used as shorthand when the common prefix of
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
- 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
- tilde-prefix following the tilde are treated as a possible _\bl_\bo_\bg_\bi_\bn _\bn_\ba_\bm_\be.
- If this login name is the null string, the tilde is replaced with the
- value of the shell parameter H\bHO\bOM\bME\bE. If H\bHO\bOM\bME\bE is unset, the home direc-
- tory of the user executing the shell is substituted instead. Other-
- wise, the tilde-prefix is replaced with the home directory associated
+ 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
+ tilde-prefix following the tilde are treated as a possible _\bl_\bo_\bg_\bi_\bn _\bn_\ba_\bm_\be.
+ If this login name is the null string, the tilde is replaced with the
+ value of the shell parameter H\bHO\bOM\bME\bE. If H\bHO\bOM\bME\bE is unset, the home direc-
+ tory of the user executing the shell is substituted instead. Other-
+ 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
+ If the tilde-prefix is a `~+', the value of the shell variable P\bPW\bWD\bD
replaces 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
+ 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
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-
+ ment. If the characters following the tilde in the tilde-prefix con-
sist of a number without a leading `+' or `-', `+' is assumed.
If the login name is invalid, or the tilde expansion fails, the word is
Each variable assignment is checked for unquoted tilde-prefixes immedi-
ately following a :\b: or the first =\b=. In these cases, tilde expansion is
- also performed. Consequently, one may use file names with tildes in
- assignments to P\bPA\bAT\bTH\bH, M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH, and C\bCD\bDP\bPA\bAT\bTH\bH, and the shell assigns the
+ also performed. Consequently, one may use file names with tildes in
+ assignments to P\bPA\bAT\bTH\bH, M\bMA\bAI\bIL\bLP\bPA\bAT\bTH\bH, and C\bCD\bDP\bPA\bAT\bTH\bH, and the shell assigns the
expanded value.
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,
- 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
+ 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
- escaped by a backslash or within a quoted string, and not within an
+ 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
embedded arithmetic expansion, command substitution, or parameter
expansion.
${_\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.
If the first character of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an exclamation point, a level of
- variable indirection is introduced. B\bBa\bas\bsh\bh uses the value of the vari-
- able formed from the rest of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br as the name of the variable;
- this variable is then expanded and that value is used in the rest of
- the substitution, rather than the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br itself. This is
+ variable indirection is introduced. B\bBa\bas\bsh\bh uses the value of the vari-
+ able formed from the rest of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br as the name of the variable;
+ this variable is then expanded and that value is used in the rest of
+ the substitution, rather than the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br itself. This is
known as _\bi_\bn_\bd_\bi_\br_\be_\bc_\bt _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn. The exceptions to this are the expansions
- of ${!_\bp_\br_\be_\bf_\bi_\bx*} and ${!\b!_\bn_\ba_\bm_\be[_\b@]} described below. The exclamation point
- must immediately follow the left brace in order to introduce indirec-
+ of ${!_\bp_\br_\be_\bf_\bi_\bx*} and ${!\b!_\bn_\ba_\bm_\be[_\b@]} described below. The exclamation point
+ must immediately follow the left brace in order to introduce indirec-
tion.
In each of the cases below, _\bw_\bo_\br_\bd is subject to tilde expansion, parame-
- ter expansion, command substitution, and arithmetic expansion. When
- not performing substring expansion, b\bba\bas\bsh\bh tests for a parameter that is
- unset or null; omitting the colon results in a test only for a parame-
+ ter expansion, command substitution, and arithmetic expansion. When
+ not performing substring expansion, b\bba\bas\bsh\bh tests for a parameter that is
+ unset or null; omitting the colon results in a test only for a parame-
ter that is unset.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br:\b:-\b-_\bw_\bo_\br_\bd}
- U\bUs\bse\be D\bDe\bef\bfa\bau\bul\blt\bt V\bVa\bal\blu\bue\bes\bs. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is unset or null, the expan-
- sion of _\bw_\bo_\br_\bd is substituted. Otherwise, the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br
+ U\bUs\bse\be D\bDe\bef\bfa\bau\bul\blt\bt V\bVa\bal\blu\bue\bes\bs. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is unset or null, the expan-
+ sion of _\bw_\bo_\br_\bd is substituted. 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}
- A\bAs\bss\bsi\big\bgn\bn D\bDe\bef\bfa\bau\bul\blt\bt V\bVa\bal\blu\bue\bes\bs. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is unset or null, the
+ A\bAs\bss\bsi\big\bgn\bn D\bDe\bef\bfa\bau\bul\blt\bt V\bVa\bal\blu\bue\bes\bs. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is unset or null, the
expansion of _\bw_\bo_\br_\bd is assigned to _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. The value of _\bp_\ba_\br_\ba_\bm_\b-
- _\be_\bt_\be_\br is then substituted. Positional parameters and special
+ _\be_\bt_\be_\br is then substituted. Positional parameters and special
parameters may not be assigned to in this way.
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br:\b:?\b?_\bw_\bo_\br_\bd}
- D\bDi\bis\bsp\bpl\bla\bay\by E\bEr\brr\bro\bor\br i\bif\bf N\bNu\bul\bll\bl o\bor\br U\bUn\bns\bse\bet\bt. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is null or unset,
- the expansion of _\bw_\bo_\br_\bd (or a message to that effect if _\bw_\bo_\br_\bd is
- not present) is written to the standard error and the shell, if
+ D\bDi\bis\bsp\bpl\bla\bay\by E\bEr\brr\bro\bor\br i\bif\bf N\bNu\bul\bll\bl o\bor\br U\bUn\bns\bse\bet\bt. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is null or unset,
+ the expansion of _\bw_\bo_\br_\bd (or a message to that effect if _\bw_\bo_\br_\bd is
+ not present) is written to the standard error and the shell, if
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.\b. Expands to up to _\bl_\be_\bn_\bg_\bt_\bh characters of
- _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br starting at the character specified by _\bo_\bf_\bf_\bs_\be_\bt. If
- _\bl_\be_\bn_\bg_\bt_\bh is omitted, expands to the substring of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br start-
+ S\bSu\bub\bbs\bst\btr\bri\bin\bng\bg E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn.\b. Expands to up to _\bl_\be_\bn_\bg_\bt_\bh characters of
+ _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br starting at the character specified by _\bo_\bf_\bf_\bs_\be_\bt. If
+ _\bl_\be_\bn_\bg_\bt_\bh is omitted, expands to the substring of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br start-
ing at the character specified by _\bo_\bf_\bf_\bs_\be_\bt. _\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).
- _\bl_\be_\bn_\bg_\bt_\bh must evaluate to a number greater than or equal to zero.
- If _\bo_\bf_\bf_\bs_\be_\bt evaluates to a number less than zero, the value is
- used as an offset from the end of the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. If
- _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@, the result is _\bl_\be_\bn_\bg_\bt_\bh positional parameters
+ 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).
+ _\bl_\be_\bn_\bg_\bt_\bh must evaluate to a number greater than or equal to zero.
+ If _\bo_\bf_\bf_\bs_\be_\bt evaluates to a number less than zero, the value is
+ used as an offset from the end of the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. If
+ _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@, the result is _\bl_\be_\bn_\bg_\bt_\bh positional parameters
beginning at _\bo_\bf_\bf_\bs_\be_\bt. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is an array name indexed by @
- or *, the result is the _\bl_\be_\bn_\bg_\bt_\bh members of the array beginning
- with ${_\bp_\ba_\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 greater than the maximum index of the specified array.
- Note that a negative offset must be separated from the colon by
- at least one space to avoid being confused with the :- expan-
- sion. Substring indexing is zero-based unless the positional
- parameters are used, in which case the indexing starts at 1 by
- default. If _\bo_\bf_\bf_\bs_\be_\bt is 0, and the positional parameters are
+ or *, the result is the _\bl_\be_\bn_\bg_\bt_\bh members of the array beginning
+ with ${_\bp_\ba_\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 greater than the maximum index of the specified array.
+ Note that a negative offset must be separated from the colon by
+ at least one space to avoid being confused with the :- expan-
+ sion. Substring indexing is zero-based unless the positional
+ parameters are used, in which case the indexing starts at 1 by
+ default. If _\bo_\bf_\bf_\bs_\be_\bt is 0, and the positional parameters are
used, $\b$0\b0 is prefixed to the list.
${!\b!_\bp_\br_\be_\bf_\bi_\bx*\b*}
${!\b!_\bp_\br_\be_\bf_\bi_\bx@\b@}
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,
+ 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 word.
${!\b!_\bn_\ba_\bm_\be[_\b@]}
${!\b!_\bn_\ba_\bm_\be[_\b*]}
- 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
+ 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}
- The length in characters of the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is substi-
- tuted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is *\b* or @\b@, the value substituted 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
+ The length in characters of the value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is substi-
+ tuted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is *\b* or @\b@, the value substituted 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.
${_\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}
- The _\bw_\bo_\br_\bd is expanded to produce a pattern just as in pathname
+ The _\bw_\bo_\br_\bd is expanded to produce a pattern just as in pathname
expansion. 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
+ _\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 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
+ 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%_\bw_\bo_\br_\bd}
${_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br%\b%%\b%_\bw_\bo_\br_\bd}
- The _\bw_\bo_\br_\bd is expanded to produce a pattern just as in pathname
- expansion. If the pattern matches a trailing portion of the
+ The _\bw_\bo_\br_\bd is expanded to produce a pattern just as in pathname
+ expansion. 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 expansion is
- the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br with the shortest matching pat-
- tern (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 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 expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br with the shortest matching pat-
+ tern (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 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}
The _\bp_\ba_\bt_\bt_\be_\br_\bn is expanded to produce a pattern just as in pathname
- expansion. _\bP_\ba_\br_\ba_\bm_\be_\bt_\be_\br is expanded and the longest match of _\bp_\ba_\bt_\b-
- _\bt_\be_\br_\bn against its value is replaced with _\bs_\bt_\br_\bi_\bn_\bg. If Ipattern
- _\bb_\be_\bg_\bi_\bn_\bs _\bw_\bi_\bt_\bh /\b/_\b, _\ba_\bl_\bl _\bm_\ba_\bt_\bc_\bh_\be_\bs _\bo_\bf _\bp_\ba_\bt_\bt_\be_\br_\bn _\ba_\br_\be _\br_\be_\bp_\bl_\ba_\bc_\be_\bd _\bw_\bi_\bt_\bh _\bs_\bt_\br_\bi_\bn_\bg_\b.
- _\bN_\bo_\br_\bm_\ba_\bl_\bl_\by _\bo_\bn_\bl_\by _\bt_\bh_\be _\bf_\bi_\br_\bs_\bt _\bm_\ba_\bt_\bc_\bh _\bi_\bs _\br_\be_\bp_\bl_\ba_\bc_\be_\bd_\b. _\bI_\bf _\bp_\ba_\bt_\bt_\be_\br_\bn _\bb_\be_\bg_\bi_\bn_\bs
- _\bw_\bi_\bt_\bh #\b#_\b, _\bi_\bt _\bm_\bu_\bs_\bt _\bm_\ba_\bt_\bc_\bh _\ba_\bt _\bt_\bh_\be _\bb_\be_\bg_\bi_\bn_\bn_\bi_\bn_\bg _\bo_\bf _\bt_\bh_\be _\be_\bx_\bp_\ba_\bn_\bd_\be_\bd _\bv_\ba_\bl_\bu_\be _\bo_\bf
- _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br_\b. _\bI_\bf _\bp_\ba_\bt_\bt_\be_\br_\bn _\bb_\be_\bg_\bi_\bn_\bs _\bw_\bi_\bt_\bh %\b%_\b, _\bi_\bt _\bm_\bu_\bs_\bt _\bm_\ba_\bt_\bc_\bh _\ba_\bt _\bt_\bh_\be _\be_\bn_\bd
- _\bo_\bf _\bt_\bh_\be _\be_\bx_\bp_\ba_\bn_\bd_\be_\bd _\bv_\ba_\bl_\bu_\be _\bo_\bf _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br_\b. _\bI_\bf _\bs_\bt_\br_\bi_\bn_\bg _\bi_\bs _\bn_\bu_\bl_\bl_\b, _\bm_\ba_\bt_\bc_\bh_\be_\bs
- _\bo_\bf _\bp_\ba_\bt_\bt_\be_\br_\bn _\ba_\br_\be _\bd_\be_\bl_\be_\bt_\be_\bd _\ba_\bn_\bd _\bt_\bh_\be /\b/ _\bf_\bo_\bl_\bl_\bo_\bw_\bi_\bn_\bg _\bp_\ba_\bt_\bt_\be_\br_\bn _\bm_\ba_\by _\bb_\be _\bo_\bm_\bi_\bt_\b-
- _\bt_\be_\bd_\b. _\bI_\bf _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the substitution 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 sub-
- scripted with @\b@ or *\b*, the substitution operation is applied to
- each member of the array in turn, and the expansion is the
+ expansion. _\bP_\ba_\br_\ba_\bm_\be_\bt_\be_\br is expanded and the longest match of _\bp_\ba_\bt_\b-
+ _\bt_\be_\br_\bn against its value is replaced with _\bs_\bt_\br_\bi_\bn_\bg. If _\bp_\ba_\bt_\bt_\be_\br_\bn
+ begins with /\b/, all matches of _\bp_\ba_\bt_\bt_\be_\br_\bn are replaced with _\bs_\bt_\br_\bi_\bn_\bg.
+ Normally only the first match is replaced. If _\bp_\ba_\bt_\bt_\be_\br_\bn begins
+ with #\b#, 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 begins with %\b%, it must match at the end
+ of the expanded value of _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br. If _\bs_\bt_\br_\bi_\bn_\bg is 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 omit-
+ ted. If _\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br is @\b@ or *\b*, the substitution 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 sub-
+ scripted with @\b@ or *\b*, the substitution operation is applied to
+ each member of the array in turn, and the expansion is the
resultant list.
C\bCo\bom\bmm\bma\ban\bnd\bd S\bSu\bub\bbs\bst\bti\bit\btu\but\bti\bio\bon\bn
`\b`_\bc_\bo_\bm_\bm_\ba_\bn_\bd`\b`
B\bBa\bas\bsh\bh performs the expansion by executing _\bc_\bo_\bm_\bm_\ba_\bn_\bd and replacing the com-
- mand substitution with the standard output of the command, with any
+ mand 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 $\b$(\b(c\bca\bat\bt
+ may be removed during word splitting. The command substitution $\b$(\b(c\bca\bat\bt
_\bf_\bi_\bl_\be)\b) can be replaced by the equivalent but faster $\b$(\b(<\b< _\bf_\bi_\bl_\be)\b).
- When the old-style backquote form of substitution is used, backslash
- retains its literal meaning except when followed by $\b$, `\b`, or \\b\. The
+ When the old-style backquote form of substitution is used, backslash
+ retains its literal meaning except when followed by $\b$, `\b`, or \\b\. The
first backquote not preceded by a backslash terminates the command sub-
- stitution. When using the $(_\bc_\bo_\bm_\bm_\ba_\bn_\bd) form, all characters between the
+ stitution. When using the $(_\bc_\bo_\bm_\bm_\ba_\bn_\bd) form, all characters between the
parentheses make up the command; none are treated specially.
Command substitutions may be nested. To nest when using the backquoted
form, escape the inner backquotes with backslashes.
- If the substitution appears within double quotes, word splitting and
+ If the substitution appears within double quotes, word splitting and
pathname expansion are not performed on the results.
A\bAr\bri\bit\bth\bhm\bme\bet\bti\bic\bc E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
- Arithmetic expansion allows the evaluation of an arithmetic expression
- and the substitution of the result. The format for arithmetic expan-
+ Arithmetic expansion allows the evaluation of an arithmetic expression
+ and the substitution of the result. The format for arithmetic expan-
sion is:
$\b$(\b((\b(_\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn)\b))\b)
- The _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn is treated as if it were within double quotes, but a
- double quote inside the parentheses is not treated specially. All
+ The _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn is treated as if it were within double quotes, but a
+ double quote inside the parentheses is not treated specially. All
tokens in the expression undergo parameter expansion, string expansion,
- command substitution, and quote removal. Arithmetic expansions may be
+ command substitution, and quote removal. Arithmetic expansions may be
nested.
- The evaluation is performed according to the rules listed below under
+ The evaluation is performed according to the rules listed below under
A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN. If _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn is invalid, b\bba\bas\bsh\bh prints a message
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 is supported on systems that support named pipes
- (_\bF_\bI_\bF_\bO_\bs) or the /\b/d\bde\bev\bv/\b/f\bfd\bd method of naming open files. 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 with its input or out-
+ _\bP_\br_\bo_\bc_\be_\bs_\bs _\bs_\bu_\bb_\bs_\bt_\bi_\bt_\bu_\bt_\bi_\bo_\bn is supported on systems that support named pipes
+ (_\bF_\bI_\bF_\bO_\bs) or the /\b/d\bde\bev\bv/\b/f\bfd\bd method of naming open files. 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 with its input or out-
put connected to a _\bF_\bI_\bF_\bO or some file in /\b/d\bde\bev\bv/\b/f\bfd\bd. The name of this file
- is passed as an argument to the current command as the result of the
- expansion. If the >\b>(\b(_\bl_\bi_\bs_\bt)\b) form is used, writing to the file will pro-
- vide input for _\bl_\bi_\bs_\bt. If the <\b<(\b(_\bl_\bi_\bs_\bt)\b) form is used, the file passed as
+ is passed as an argument to the current command as the result of the
+ expansion. If the >\b>(\b(_\bl_\bi_\bs_\bt)\b) form is used, writing to the file will pro-
+ vide input for _\bl_\bi_\bs_\bt. If the <\b<(\b(_\bl_\bi_\bs_\bt)\b) form is used, the file passed as
an argument should be read to obtain the output of _\bl_\bi_\bs_\bt.
- 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
+ The shell treats each character of I\bIF\bFS\bS as a delimiter, and splits the
results of the other expansions into words on these characters. 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 default,
- then sequences of <\b<s\bsp\bpa\bac\bce\be>\b>, <\b<t\bta\bab\bb>\b>, and <\b<n\bne\bew\bwl\bli\bin\bne\be>\b> at the beginning and
- end of the results of the previous expansions are ignored, and any
- sequence of I\bIF\bFS\bS characters not at the beginning or end serves to
- delimit words. If I\bIF\bFS\bS has a value other than the default, then
+ 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 default,
+ then sequences of <\b<s\bsp\bpa\bac\bce\be>\b>, <\b<t\bta\bab\bb>\b>, and <\b<n\bne\bew\bwl\bli\bin\bne\be>\b> at the beginning and
+ end of the results of the previous expansions are ignored, and any
+ sequence of I\bIF\bFS\bS characters not at the beginning or end serves to
+ delimit words. If I\bIF\bFS\bS has a value other than the default, then
sequences of the whitespace characters s\bsp\bpa\bac\bce\be and t\bta\bab\bb are ignored at the
- beginning and end of the word, as long as the whitespace character is
- in the value of I\bIF\bFS\bS (an I\bIF\bFS\bS whitespace character). Any character in
- I\bIF\bFS\bS that is not I\bIF\bFS\bS whitespace, along with any adjacent I\bIF\bFS\bS whitespace
- characters, delimits a field. A sequence of I\bIF\bFS\bS whitespace characters
- is also treated as a delimiter. If the value of I\bIF\bFS\bS is null, no word
+ beginning and end of the word, as long as the whitespace character is
+ in the value of I\bIF\bFS\bS (an I\bIF\bFS\bS whitespace character). Any character in
+ I\bIF\bFS\bS that is not I\bIF\bFS\bS whitespace, along with any adjacent I\bIF\bFS\bS whitespace
+ characters, delimits a field. A sequence of I\bIF\bFS\bS whitespace characters
+ is also treated as a delimiter. If the value of I\bIF\bFS\bS is null, no word
splitting occurs.
- Explicit null arguments ("\b""\b" or '\b''\b') are retained. Unquoted implicit
+ Explicit null arguments ("\b""\b" or '\b''\b') are retained. 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
+ values, are removed. If a parameter with no value is expanded within
double quotes, a null argument results and is retained.
Note that if no expansion occurs, no splitting is performed.
P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
- 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, then the word is regarded as a _\bp_\ba_\bt_\bt_\be_\br_\bn, and replaced with an
- alphabetically sorted list of file names matching the pattern. If no
- matching file names are found, and the shell option n\bnu\bul\bll\blg\bgl\blo\bob\bb is dis-
- abled, 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 performed without regard to the case of alpha-
- betic 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 explicitly, unless the shell option d\bdo\bot\btg\bgl\blo\bob\bb is
- set. When matching a pathname, the slash character must always be
- matched explicitly. In other cases, the `\b``\b`.\b.'\b''\b' character is not
- treated specially. 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, f\bfa\bai\bil\bl-\b-
+ 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, then the word is regarded as a _\bp_\ba_\bt_\bt_\be_\br_\bn, and replaced with an
+ alphabetically sorted list of file names matching the pattern. If no
+ matching file names are found, and the shell option n\bnu\bul\bll\blg\bgl\blo\bob\bb is dis-
+ abled, 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 performed without regard to the case of alpha-
+ betic 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 explicitly, unless the shell option d\bdo\bot\btg\bgl\blo\bob\bb is
+ set. When matching a pathname, the slash character must always be
+ matched explicitly. In other cases, the `\b``\b`.\b.'\b''\b' character is not
+ treated specially. 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, f\bfa\bai\bil\bl-\b-
g\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
+ 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. The file names `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b' 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\bG-\b-
- N\bNO\bOR\bRE\bE to a non-null value has the effect of enabling the d\bdo\bot\btg\bgl\blo\bob\bb shell
+ 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\bG-\b-
+ N\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 file names beginning with a `\b``\b`.\b.'\b''\b' will match. To
- get the old behavior of ignoring file names 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
+ get the old behavior of ignoring file names 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.
P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg
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. 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. The special pattern
characters must be quoted if they are to be matched literally.
The special pattern characters have the following meanings:
*\b* Matches any string, including the null string.
?\b? Matches any single character.
- [\b[.\b..\b..\b.]\b] Matches any one of the enclosed characters. A pair of charac-
+ [\b[.\b..\b..\b.]\b] Matches any one of the enclosed characters. A pair of charac-
ters separated by a hyphen denotes a _\br_\ba_\bn_\bg_\be _\be_\bx_\bp_\br_\be_\bs_\bs_\bi_\bo_\bn; any char-
- acter that sorts between those two characters, inclusive, using
- the current locale's collating sequence and character set, is
- matched. If the first character following the [\b[ is a !\b! or a ^\b^
- then any character not enclosed is matched. The sorting order
- of characters in range expressions is determined by the current
- locale and the value of the L\bLC\bC_\b_C\bCO\bOL\bLL\bLA\bAT\bTE\bE shell variable, if set.
- A -\b- may be matched by including it as the first or last charac-
+ acter that sorts between those two characters, inclusive, using
+ the current locale's collating sequence and character set, is
+ matched. If the first character following the [\b[ is a !\b! or a ^\b^
+ then any character not enclosed is matched. The sorting order
+ of characters in range expressions is determined by the current
+ locale and the value of the L\bLC\bC_\b_C\bCO\bOL\bLL\bLA\bAT\bTE\bE shell variable, if set.
+ A -\b- may be matched by including it as the first or last charac-
ter 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 the
- syntax [\b[:\b:_\bc_\bl_\ba_\bs_\bs:\b:]\b], where _\bc_\bl_\ba_\bs_\bs is one of the following classes
+ 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
+ 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 char-
+ The w\bwo\bor\brd\bd character class matches letters, digits, and the char-
acter _.
- Within [\b[ and ]\b], an _\be_\bq_\bu_\bi_\bv_\ba_\bl_\be_\bn_\bc_\be _\bc_\bl_\ba_\bs_\bs can be specified using the
- syntax [\b[=\b=_\bc=\b=]\b], which matches all characters with the same colla-
- tion weight (as defined by the current locale) as 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 using the
+ syntax [\b[=\b=_\bc=\b=]\b], which matches all characters with the same colla-
+ tion weight (as defined by the current locale) as the character
_\bc.
Within [\b[ and ]\b], the syntax [\b[.\b._\bs_\by_\bm_\bb_\bo_\bl.\b.]\b] matches the collating sym-
bol _\bs_\by_\bm_\bb_\bo_\bl.
If the e\bex\bxt\btg\bgl\blo\bob\bb shell option is enabled using the s\bsh\bho\bop\bpt\bt builtin, several
- extended pattern matching operators are recognized. In the following
+ extended pattern matching operators are recognized. 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 of the fol-
lowing sub-patterns:
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. Redirection may
- also be used to open and close files for the current shell execution
+ 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. Redirection may
+ also be used to open and close files for the current shell execution
environment. The following redirection operators may precede or appear
anywhere within a _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd or may follow a _\bc_\bo_\bm_\bm_\ba_\bn_\bd. Redirections
are processed in the order they appear, from left to right.
- 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 re-
+ direction 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
+ The word following the redirection operator in the following descrip-
+ tions, unless otherwise noted, is subjected to brace expansion, tilde
expansion, parameter expansion, command substitution, arithmetic expan-
- sion, quote removal, pathname expansion, and word splitting. If it
+ sion, 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 as standard output before the standard output was
+ directs only the standard output to file _\bd_\bi_\br_\bl_\bi_\bs_\bt, because the standard
+ error was duplicated as standard output before the standard output 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-
tions, as described in the following table:
/\b/d\bde\bev\bv/\b/f\bfd\bd/\b/_\bf_\bd
- If _\bf_\bd is a valid integer, file descriptor _\bf_\bd is dupli-
+ If _\bf_\bd is a valid integer, file descriptor _\bf_\bd is dupli-
cated.
/\b/d\bde\bev\bv/\b/s\bst\btd\bdi\bin\bn
File descriptor 0 is duplicated.
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 a TCP connection to the corresponding 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
- 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 a UDP connection to the corresponding socket.
A failure to open or create a file causes the redirection to fail.
- Redirections using file descriptors greater than 9 should be used with
- care, as they may conflict with file descriptors the shell uses inter-
+ Redirections using file descriptors greater than 9 should be used with
+ care, as they may conflict with file descriptors the shell uses inter-
nally.
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
+ Redirection of output causes the file whose name results from the
expansion 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
+ does not exist it is created; if it does exist it is truncated to zero
size.
The general format for redirecting output is:
[_\bn]>\b>_\bw_\bo_\br_\bd
- If 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 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>, and the n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br option to the s\bse\bet\bt
+ 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.
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
- results from the expansion of _\bw_\bo_\br_\bd to be opened for appending on file
- descriptor _\bn, or the standard output (file descriptor 1) if _\bn is not
+ Redirection of output in this fashion causes the file whose name
+ results from the expansion of _\bw_\bo_\br_\bd to be opened for appending 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.
The general format for appending output is:
R\bRe\bed\bdi\bir\bre\bec\bct\bti\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
- B\bBa\bas\bsh\bh allows both the standard output (file descriptor 1) and the stan-
- dard error output (file descriptor 2) to be redirected to the file
+ B\bBa\bas\bsh\bh allows both the standard output (file descriptor 1) and the stan-
+ dard error output (file descriptor 2) to be redirected to the file
whose name is the expansion of _\bw_\bo_\br_\bd with this construct.
- There are two formats for redirecting standard output and standard
+ There are two formats for redirecting standard output and standard
error:
&\b&>\b>_\bw_\bo_\br_\bd
>\b>_\bw_\bo_\br_\bd 2>\b>&\b&1
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
- current source until a line containing only _\bw_\bo_\br_\bd (with no trailing
- blanks) is seen. All of the lines read up to that point are then used
+ This type of redirection instructs the shell to read input from the
+ current source until a line containing only _\bw_\bo_\br_\bd (with no trailing
+ blanks) is seen. All of the lines read up to that point are then used
as the standard input 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 expansion, command substitution, arithmetic expansion, or
+ No parameter expansion, command substitution, arithmetic expansion, or
pathname expansion is performed on _\bw_\bo_\br_\bd. If any characters in _\bw_\bo_\br_\bd are
- quoted, the _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br is the result of quote removal on _\bw_\bo_\br_\bd, and the
- lines in the here-document are not expanded. If _\bw_\bo_\br_\bd is unquoted, all
- lines of the here-document are subjected to parameter expansion, com-
- mand substitution, and arithmetic expansion. In the latter case, the
- character sequence \\b\<\b<n\bne\bew\bwl\bli\bin\bne\be>\b> is ignored, and \\b\ must be used to quote
+ quoted, the _\bd_\be_\bl_\bi_\bm_\bi_\bt_\be_\br is the result of quote removal on _\bw_\bo_\br_\bd, and the
+ lines in the here-document are not expanded. If _\bw_\bo_\br_\bd is unquoted, all
+ lines of the here-document are subjected to parameter expansion, com-
+ mand substitution, and arithmetic expansion. In the latter case, 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
- allows 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
+ allows 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&_\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
- descriptor open for input, a redirection error occurs. If _\bw_\bo_\br_\bd evalu-
- ates to -\b-, file descriptor _\bn is closed. If _\bn is not specified, the
+ 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
+ descriptor open for input, a redirection error occurs. If _\bw_\bo_\br_\bd evalu-
+ ates to -\b-, file descriptor _\bn is closed. If _\bn is not specified, the
standard input (file descriptor 0) is used.
The operator
[_\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. As a special case, if _\bn is omitted, and _\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. As a special case, if _\bn is omitted, and _\bw_\bo_\br_\bd
does not expand to one or more digits, 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
input (file descriptor 0) if _\bn is not specified. _\bd_\bi_\bg_\bi_\bt is closed after
being duplicated to _\bn.
[_\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 when it is used as
- the first word of a simple command. The shell maintains a list of
- aliases that may be set and unset with 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). The first word of each
- simple command, if unquoted, is checked to see if it has an alias. If
- so, that word is replaced by the text of the alias. The characters /\b/,
- $\b$, `\b`, and =\b= and any of the shell _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br_\bs or quoting characters
+ _\bA_\bl_\bi_\ba_\bs_\be_\bs allow a string to be substituted for a word when it is used as
+ the first word of a simple command. The shell maintains a list of
+ aliases that may be set and unset with 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). The first word of each
+ simple command, if unquoted, is checked to see if it has an alias. If
+ so, that word is replaced by the text of the alias. The characters /\b/,
+ $\b$, `\b`, and =\b= and any of the shell _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br_\bs 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 l\bls\bs to l\bls\bs -\b-F\bF, for instance, and
- b\bba\bas\bsh\bh does not try to recursively expand the replacement text. If the
- last character of the alias value is a _\bb_\bl_\ba_\bn_\bk, then the next command
+ 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 l\bls\bs to l\bls\bs -\b-F\bF, for instance, and
+ b\bba\bas\bsh\bh does not try to recursively expand the replacement text. If the
+ last character of the alias value is a _\bb_\bl_\ba_\bn_\bk, then the next command
word following the alias is also checked for alias expansion.
Aliases are created and listed with the a\bal\bli\bia\bas\bs command, and removed with
the u\bun\bna\bal\bli\bia\bas\bs command.
- There is no mechanism for using arguments in the replacement text. If
- arguments are needed, a shell function should be used (see F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS
+ There is no mechanism for using arguments in the replacement text. If
+ arguments are needed, a shell function should be used (see F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS
below).
- Aliases are not expanded when the shell is not interactive, unless the
- e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs shell option is set using s\bsh\bho\bop\bpt\bt (see the description of
+ Aliases are not expanded when the shell is not interactive, unless the
+ e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs shell option is set using s\bsh\bho\bop\bpt\bt (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 rules concerning the definition and use of aliases are somewhat
- confusing. B\bBa\bas\bsh\bh always reads at least one complete line of input
- before executing any of the commands on that line. Aliases are
- expanded when a command is read, not when it is executed. Therefore,
- an alias definition appearing on the same line as another command does
- not take effect until the next line of input is read. The commands
+ The rules concerning the definition and use of aliases are somewhat
+ confusing. B\bBa\bas\bsh\bh always reads at least one complete line of input
+ before executing any of the commands on that line. Aliases are
+ expanded when a command is read, not when it is executed. Therefore,
+ an alias definition appearing on the same line as another command does
+ not take effect until the next line of input is read. The commands
following the alias definition on that line are not affected by the new
- alias. This behavior is also an issue when functions are executed.
- Aliases are expanded when a function definition is read, not when the
- function is executed, because a function definition is itself a com-
+ alias. This behavior is also an issue when functions are executed.
+ Aliases are expanded when a function definition is read, not when the
+ function is executed, because a function definition is itself a com-
pound 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 a\bal\bli\bia\bas\bs in com-
+ available until after that function is executed. To be safe, always
+ put alias definitions on a separate line, and do not use a\bal\bli\bia\bas\bs in com-
pound commands.
For almost every purpose, aliases are superseded by shell functions.
F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS
- A shell function, defined as described above under S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR,
- 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
+ A shell function, defined as described above under S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR,
+ 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
- interpret 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
+ interpret 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 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-
- tion while the function is executing. All other aspects of the shell
- execution environment are identical between a function and its caller
+ updated to reflect the change. Special parameter 0 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-
+ tion while the function is executing. All other aspects of the shell
+ execution environment are identical between a function and its caller
with the exception that the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps (see the description
- of the t\btr\bra\bap\bp builtin 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) are not inher-
- ited unless the function has been given the t\btr\bra\bac\bce\be attribute (see the
- description of the d\bde\bec\bcl\bla\bar\bre\be builtin below) or the -\b-o\bo f\bfu\bun\bnc\bct\btr\bra\bac\bce\be shell
- option has been enabled with the s\bse\bet\bt builtin (in which case all func-
+ of the t\btr\bra\bap\bp builtin 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) are not inher-
+ ited unless the function has been given the t\btr\bra\bac\bce\be attribute (see the
+ description of the d\bde\bec\bcl\bla\bar\bre\be builtin below) or the -\b-o\bo f\bfu\bun\bnc\bct\btr\bra\bac\bce\be shell
+ option has been enabled with the s\bse\bet\bt builtin (in which case all func-
tions inherit the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps).
- Variables local to the function may be declared with the l\blo\boc\bca\bal\bl builtin
+ Variables local to the function may be declared with the l\blo\boc\bca\bal\bl builtin
command. Ordinarily, variables and their values are shared between the
function and its caller.
- 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
+ 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
before execution resumes. When a function completes, the values of the
- positional parameters and the special parameter #\b# are restored to the
+ positional parameters and the special parameter #\b# are restored to the
values they had prior to the function's execution.
- Function names and definitions may be listed with the -\b-f\bf option 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 subshells 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. Note that shell
+ 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 subshells 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. Note that shell
functions and variables with the same name may result in multiple iden-
- tically-named entries in the environment passed to the shell's chil-
+ tically-named entries in the environment passed to the shell's chil-
dren. Care should be taken in cases where this may cause a problem.
- Functions may be recursive. No limit is imposed on the number of
+ Functions may be recursive. No limit is imposed on the number of
recursive calls.
A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN
- 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 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 following list of operators is grouped
- into levels of equal-precedence operators. The levels are listed in
+ 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 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 following list of operators is grouped
+ into levels of equal-precedence operators. The levels are listed in
order of decreasing precedence.
_\bi_\bd+\b++\b+ _\bi_\bd-\b--\b-
_\be_\bx_\bp_\br_\b1 ,\b, _\be_\bx_\bp_\br_\b2
comma
- Shell variables are allowed as operands; parameter expansion is per-
+ 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
+ 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 integer attribute turned on
+ to 0. A shell variable need not have its integer attribute turned on
to be used in an expression.
Constants with a leading 0 are interpreted as octal numbers. A leading
- 0x or 0X denotes hexadecimal. Otherwise, numbers take the form
- [_\bb_\ba_\bs_\be_\b#]n, where _\bb_\ba_\bs_\be is a decimal number between 2 and 64 representing
+ 0x or 0X denotes hexadecimal. Otherwise, numbers take the form
+ [_\bb_\ba_\bs_\be_\b#]n, where _\bb_\ba_\bs_\be is a decimal number between 2 and 64 representing
the arithmetic base, and _\bn is a number in that base. If _\bb_\ba_\bs_\be_\b# is omit-
- ted, then base 10 is used. 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 uppercase
+ ted, then base 10 is used. 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 uppercase
letters may be used interchangeably to represent numbers between 10 and
35.
- Operators are evaluated in order of precedence. Sub-expressions in
- parentheses are evaluated first and may override the precedence rules
+ Operators are evaluated in order of precedence. Sub-expressions in
+ parentheses are evaluated first and may override the precedence rules
above.
C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS
- Conditional expressions are used by the [\b[[\b[ compound command and the
- t\bte\bes\bst\bt and [\b[ builtin commands to test file attributes and perform string
- and arithmetic comparisons. Expressions are formed from the following
- unary or binary primaries. If any _\bf_\bi_\bl_\be argument to one of the pri-
+ Conditional expressions are used by the [\b[[\b[ compound command and the
+ t\bte\bes\bst\bt and [\b[ builtin commands to test file attributes and perform string
+ and arithmetic comparisons. Expressions are formed from the following
+ unary or binary primaries. 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,
+ 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,
is checked.
Unless otherwise specified, primaries that operate on files follow sym-
-\b-S\bS _\bf_\bi_\bl_\be
True if _\bf_\bi_\bl_\be exists and is a socket.
-\b-N\bN _\bf_\bi_\bl_\be
- True if _\bf_\bi_\bl_\be exists and has been modified since it was last
+ True if _\bf_\bi_\bl_\be exists and has been modified since it was last
read.
_\bf_\bi_\bl_\be_\b1 -n\bnt\bt _\bf_\bi_\bl_\be_\b2
- True if _\bf_\bi_\bl_\be_\b1 is newer (according to modification date) than
+ True if _\bf_\bi_\bl_\be_\b1 is newer (according to modification date) than
_\bf_\bi_\bl_\be_\b2, or if _\bf_\bi_\bl_\be_\b1 exists and _\bf_\bi_\bl_\be_\b2 does not.
_\bf_\bi_\bl_\be_\b1 -o\bot\bt _\bf_\bi_\bl_\be_\b2
- True if _\bf_\bi_\bl_\be_\b1 is older than _\bf_\bi_\bl_\be_\b2, or if _\bf_\bi_\bl_\be_\b2 exists and _\bf_\bi_\bl_\be_\b1
+ True if _\bf_\bi_\bl_\be_\b1 is older than _\bf_\bi_\bl_\be_\b2, or if _\bf_\bi_\bl_\be_\b2 exists and _\bf_\bi_\bl_\be_\b1
does not.
_\bf_\bi_\bl_\be_\b1 -\b-e\bef\bf _\bf_\bi_\bl_\be_\b2
- True if _\bf_\bi_\bl_\be_\b1 and _\bf_\bi_\bl_\be_\b2 refer to the same device and inode num-
+ True if _\bf_\bi_\bl_\be_\b1 and _\bf_\bi_\bl_\be_\b2 refer to the same device and inode num-
bers.
-\b-o\bo _\bo_\bp_\bt_\bn_\ba_\bm_\be
- True if shell option _\bo_\bp_\bt_\bn_\ba_\bm_\be is enabled. See the list of
- options under the description of the -\b-o\bo option to the s\bse\bet\bt
+ True if shell option _\bo_\bp_\bt_\bn_\ba_\bm_\be is enabled. See the list of
+ options under the description of the -\b-o\bo option to the s\bse\bet\bt
builtin below.
-\b-z\bz _\bs_\bt_\br_\bi_\bn_\bg
True if the length of _\bs_\bt_\br_\bi_\bn_\bg is zero.
True if the strings are not equal.
_\bs_\bt_\br_\bi_\bn_\bg_\b1 <\b< _\bs_\bt_\br_\bi_\bn_\bg_\b2
- True if _\bs_\bt_\br_\bi_\bn_\bg_\b1 sorts before _\bs_\bt_\br_\bi_\bn_\bg_\b2 lexicographically in the
+ True if _\bs_\bt_\br_\bi_\bn_\bg_\b1 sorts before _\bs_\bt_\br_\bi_\bn_\bg_\b2 lexicographically in the
current locale.
_\bs_\bt_\br_\bi_\bn_\bg_\b1 >\b> _\bs_\bt_\br_\bi_\bn_\bg_\b2
- True if _\bs_\bt_\br_\bi_\bn_\bg_\b1 sorts after _\bs_\bt_\br_\bi_\bn_\bg_\b2 lexicographically in the
+ True if _\bs_\bt_\br_\bi_\bn_\bg_\b1 sorts after _\bs_\bt_\br_\bi_\bn_\bg_\b2 lexicographically in the
current locale.
_\ba_\br_\bg_\b1 O\bOP\bP _\ba_\br_\bg_\b2
- O\bOP\bP is one of -\b-e\beq\bq, -\b-n\bne\be, -\b-l\blt\bt, -\b-l\ble\be, -\b-g\bgt\bt, or -\b-g\bge\be. These arithmetic
- binary operators return true if _\ba_\br_\bg_\b1 is equal to, not equal to,
- less than, less than or equal to, greater than, or greater than
- or equal to _\ba_\br_\bg_\b2, respectively. _\bA_\br_\bg_\b1 and _\ba_\br_\bg_\b2 may be positive
+ O\bOP\bP is one of -\b-e\beq\bq, -\b-n\bne\be, -\b-l\blt\bt, -\b-l\ble\be, -\b-g\bgt\bt, or -\b-g\bge\be. These arithmetic
+ binary operators return true if _\ba_\br_\bg_\b1 is equal to, not equal to,
+ less than, less than or equal to, greater than, or greater than
+ or equal to _\ba_\br_\bg_\b2, respectively. _\bA_\br_\bg_\b1 and _\ba_\br_\bg_\b2 may be positive
or negative integers.
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
+ When a simple command is executed, the shell performs the following
expansions, assignments, and redirections, from left to right.
- 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
- shell environment. Otherwise, the variables are added to the environ-
- ment of the executed command and do not affect the current shell envi-
- ronment. If any of the assignments attempts to assign a value to a
- readonly variable, an error occurs, and the command exits with a non-
+ shell environment. Otherwise, the variables are added to the environ-
+ ment of the executed command and do not affect the current shell envi-
+ ronment. If any of the assignments attempts to assign a 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
- affect the current shell environment. A redirection error causes the
+ If no command name results, redirections are performed, but do not
+ affect 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.
C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN
- After a command has been split into words, if it results in a simple
- command and an optional list of arguments, the following actions are
+ After a command has been split into words, if it results in a simple
+ command and an optional list of arguments, the following actions are
taken.
- 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 above in F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS. If the name does not match a
- function, the shell searches for it in the list of shell builtins. If
+ 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 above in F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS. 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 builtin is invoked.
- 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
- remember 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 prints an error message and returns
+ 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
+ remember 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 prints an error message and returns
an exit status of 127.
- If the search is successful, or if the command name contains one or
+ If the search is successful, or if the command name contains one or
more slashes, the shell executes the named program in a separate execu-
tion environment. Argument 0 is set to the name given, and the remain-
ing arguments to the command are set to the arguments given, if any.
- 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. A subshell is spawned 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
+ 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. A subshell is spawned 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 child.
- If the program is a file beginning with #\b#!\b!, the remainder of the first
- line specifies an interpreter for the program. The shell executes the
+ If the program is a file beginning with #\b#!\b!, the remainder of the first
+ line specifies an interpreter for the program. The shell executes the
specified interpreter on operating systems that do not handle this exe-
cutable format themselves. The arguments to the interpreter consist of
- a single optional argument following the interpreter name on the first
- line of the program, followed by the name of the program, followed by
+ a single optional argument following the interpreter name on the first
+ line of the program, followed by the name of the program, followed by
the command arguments, if any.
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
- The shell has an _\be_\bx_\be_\bc_\bu_\bt_\bi_\bo_\bn _\be_\bn_\bv_\bi_\br_\bo_\bn_\bm_\be_\bn_\bt, which consists of the follow-
+ The shell has an _\be_\bx_\be_\bc_\bu_\bt_\bi_\bo_\bn _\be_\bn_\bv_\bi_\br_\bo_\bn_\bm_\be_\bn_\bt, which consists of the follow-
ing:
- +\bo open files inherited by the shell at invocation, as modified by
+ +\bo open files inherited by the shell at invocation, as modified by
redirections supplied to the e\bex\bxe\bec\bc builtin
- +\bo the current working directory as set by c\bcd\bd, p\bpu\bus\bsh\bhd\bd, or p\bpo\bop\bpd\bd, or
+ +\bo the current working directory as set by c\bcd\bd, p\bpu\bus\bsh\bhd\bd, or p\bpo\bop\bpd\bd, or
inherited by the shell at invocation
- +\bo the file creation mode mask as set by u\bum\bma\bas\bsk\bk or inherited from
+ +\bo the file creation mode mask as set by u\bum\bma\bas\bsk\bk or inherited from
the shell's parent
+\bo current traps set by t\btr\bra\bap\bp
+\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 $\b$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
the shell's parent, and traps ignored by the shell are ignored
- A command invoked in this separate environment cannot affect the
+ A command invoked in this separate environment cannot affect the
shell's execution environment.
- Command substitution, commands grouped with parentheses, and asynchro-
+ Command substitution, commands grouped with parentheses, and asynchro-
nous commands are invoked in a subshell environment that is a duplicate
- of the shell environment, except that traps caught by the shell are
+ of the shell environment, except that traps caught by the shell are
reset to the values that the shell inherited from its parent at invoca-
tion. Builtin commands that are invoked as part of a pipeline are also
executed in a subshell environment. Changes made to the subshell envi-
ronment cannot affect the shell's execution environment.
- If a command is followed by a &\b& and job control is not active, the
- default standard input for the command is the empty file _\b/_\bd_\be_\bv_\b/_\bn_\bu_\bl_\bl.
- Otherwise, the invoked command inherits the file descriptors of the
+ If a command is followed by a &\b& and job control is not active, the
+ default standard input for the command is the empty file _\b/_\bd_\be_\bv_\b/_\bn_\bu_\bl_\bl.
+ Otherwise, the invoked command inherits the file descriptors of the
calling 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
+ The shell 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 _\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\bec\bcl\bla\bar\bre\be -\b-x\bx commands allow parameters and functions to be added to and
+ 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\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,
- replacing 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
+ ronment 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 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.
- If the -\b-k\bk option is set (see the s\bse\bet\bt builtin command below), then _\ba_\bl_\bl
- parameter assignments are placed in the environment for a command, not
+ If the -\b-k\bk option is set (see the s\bse\bet\bt builtin command below), then _\ba_\bl_\bl
+ parameter assignments are placed in the environment for a command, not
just those that precede the command name.
- When b\bba\bas\bsh\bh invokes an external command, the variable _\b_ is set to the
- full file name of the command and passed to that command in its envi-
+ When b\bba\bas\bsh\bh invokes an external command, the variable _\b_ is set to the
+ full file name of the command and passed to that command in its envi-
ronment.
E\bEX\bXI\bIT\bT S\bST\bTA\bAT\bTU\bUS\bS
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
- returns 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
+ returns 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 is greater than zero.
- Shell builtin commands return a status of 0 (_\bt_\br_\bu_\be) if successful, and
- non-zero (_\bf_\ba_\bl_\bs_\be) if an error occurs while they execute. All builtins
+ Shell builtin commands return a status of 0 (_\bt_\br_\bu_\be) if successful, and
+ non-zero (_\bf_\ba_\bl_\bs_\be) if an error occurs while they execute. All builtins
return an exit status of 2 to indicate incorrect usage.
- B\bBa\bas\bsh\bh itself returns the exit status of the last command executed,
- unless 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,
+ unless 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
+ 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
ignores S\bSI\bIG\bGT\bTT\bTI\bIN\bN, S\bSI\bIG\bGT\bTT\bTO\bOU\bU, and S\bSI\bIG\bGT\bTS\bST\bTP\bP.
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
- effect, 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-
+ inherited by the shell from its parent. When job control is not in
+ effect, 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
+ 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
+ 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
using 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
+ 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.
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
+ _\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
execution 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
+ point. A user typically employs this facility via an interactive
interface supplied jointly by the system's terminal driver 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-
- generated signals such as S\bSI\bIG\bGI\bIN\bNT\bT. These processes are said to be in
- 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
+ generated signals such as S\bSI\bIG\bGI\bIN\bNT\bT. These processes are said to be in
+ 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
+ erated signals. Only foreground processes are allowed to read from or
write to the terminal. Background processes which attempt to read from
(write to) 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 ter-
minal driver, which, unless caught, suspends the process.
- If the operating system on which b\bba\bas\bsh\bh is running supports job control,
+ 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-
ically ^\b^Z\bZ, Control-Z) while a process is running causes that process to
- 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
- returned 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
+ 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
+ returned 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.
There are a number of ways to refer to a job in the shell. The charac-
ter %\b% introduces a job name. Job number _\bn may be referred to as %\b%n\bn. 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 exam-
+ 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 exam-
ple, %\b%c\bce\be refers to a stopped c\bce\be job. 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
+ 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 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 back-
- ground. The _\bp_\br_\be_\bv_\bi_\bo_\bu_\bs _\bj_\bo_\bb may be referenced using %\b%-\b-. In output per-
+ 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 back-
+ ground. The _\bp_\br_\be_\bv_\bi_\bo_\bu_\bs _\bj_\bo_\bb may be referenced using %\b%-\b-. In output per-
taining to jobs (e.g., the output of the j\bjo\bob\bbs\bs command), the current job
- is always flagged with a +\b+, and the previous job with a -\b-. A single %
- (with no accompanying job specification) also refers to the current
+ is always flagged with a +\b+, and the previous job with a -\b-. A single %
+ (with no accompanying 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,
+ 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'.
- 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
+ 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
+ immediately. Any trap on S\bSI\bIG\bGC\bCH\bHL\bLD\bD is executed for each child that
exits.
- 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
- made without an intervening command, the shell does not print another
+ 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
+ made without an intervening command, the shell does not print another
warning, and any stopped jobs are terminated.
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 allows these prompt
- strings to be customized by inserting a number of backslash-escaped
+ 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 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
- inserted into the prompt string; an empty _\bf_\bo_\br_\bm_\ba_\bt results
+ the _\bf_\bo_\br_\bm_\ba_\bt is passed to _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3) and the result is
+ inserted into the prompt string; an empty _\bf_\bo_\br_\bm_\ba_\bt results
in a locale-specific time representation. The braces are
required
\\b\e\be an ASCII escape character (033)
\\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 current working directory, with $\b$H\bHO\bOM\bME\bE abbreviated
+ \\b\w\bw the current working directory, with $\b$H\bHO\bOM\bME\bE abbreviated
with a tilde
\\b\W\bW the basename of the current working directory, with $\b$H\bHO\bOM\bME\bE
abbreviated with a tilde
\\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
- below), while the command number is the position in the sequence of
- commands executed during the current shell session. After the string
- is decoded, it is expanded via parameter expansion, command substitu-
- tion, 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
+ 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
+ below), while the command number is the position in the sequence of
+ commands executed during the current shell session. After the string
+ is decoded, it is expanded via parameter expansion, command substitu-
+ tion, 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).
R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE
- This is the library that handles reading input when using an interac-
+ This is the library that handles reading input when using an interac-
tive shell, unless the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option is given at shell invocation.
By default, the line editing commands are similar to those of emacs. A
- vi-style line editing interface is also available. To turn off line
- editing after the shell is running, use the +\b+o\bo e\bem\bma\bac\bcs\bs or +\b+o\bo v\bvi\bi options
+ vi-style line editing interface is also available. To turn off line
+ editing after the shell is running, use the +\b+o\bo e\bem\bma\bac\bcs\bs or +\b+o\bo v\bvi\bi options
to the s\bse\bet\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).
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
+ 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
separate the chunks of text on the kill ring.
R\bRe\bea\bad\bdl\bli\bin\bne\be I\bIn\bni\bit\bti\bia\bal\bli\biz\bza\bat\bti\bio\bon\bn
- 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_\bp_\bu_\bt_\br_\bc. When a program which uses the readline library starts up,
+ 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_\bp_\bu_\bt_\br_\bc. When a program which uses the readline library 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 con-
+ 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 con-
structs. 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
- and a key sequence to which it should be bound. The name may be speci-
+ 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.
Meta-Rubout: backward-kill-word
Control-o: "> output"
- 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
+ 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).
- 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
- be specified by placing the sequence within double quotes. Some GNU
- Emacs style key escapes can be used, as in the following example, but
+ 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
+ be specified by placing the sequence within double quotes. Some GNU
+ Emacs style key escapes can be used, as in the following example, but
the symbolic character names are not recognized.
"\C-u": universal-argument
"\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
+ _\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\"\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
- 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-
+ 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:
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
+ 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, readline attempts to bind the control characters
+ If set to O\bOn\bn, readline attempts to bind the control characters
treated specially by the kernel's terminal driver to their read-
line equivalents.
c\bco\bom\bmm\bme\ben\bnt\bt-\b-b\bbe\beg\bgi\bin\bn (\b(`\b``\b`#\b#'\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
+ 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-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
in a case-insensitive fashion.
c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn-\b-q\bqu\bue\ber\bry\by-\b-i\bit\bte\bem\bms\bs (\b(1\b10\b00\b0)\b)
- This determines when the user is queried about viewing the num-
- ber of possible completions generated by the p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\be-\b-
- t\bti\bio\bon\bns\bs command. It may be set to any integer value greater than
- or equal to zero. If the number of possible completions is
+ This determines when the user is queried about viewing the num-
+ ber of possible completions generated by the p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\be-\b-
+ t\bti\bio\bon\bns\bs command. It may be set to any integer value greater than
+ or equal to zero. If the number of possible completions is
greater than or equal to the value of this variable, the user is
- asked whether or not he wishes to view them; otherwise they are
+ asked whether or not he wishes to view them; otherwise they are
simply listed on the terminal.
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
+ 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
+ prefixing an escape character (in effect, using escape as the
_\bm_\be_\bt_\ba _\bp_\br_\be_\bf_\bi_\bx).
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
- characters will be inserted into the line as if they had been
+ characters will be inserted into the line as if they had been
mapped to s\bse\bel\blf\bf-\b-i\bin\bns\bse\ber\brt\bt.
e\bed\bdi\bit\bti\bin\bng\bg-\b-m\bmo\bod\bde\be (\b(e\bem\bma\bac\bcs\bs)\b)
Controls whether readline begins with a set of key bindings sim-
v\bvi\bi.
e\ben\bna\bab\bbl\ble\be-\b-k\bke\bey\byp\bpa\bad\bd (\b(O\bOf\bff\bf)\b)
When set to O\bOn\bn, readline will try to enable the application key-
- pad when it is called. Some systems need this to enable the
+ pad when it is called. Some systems need this to enable the
arrow keys.
e\bex\bxp\bpa\ban\bnd\bd-\b-t\bti\bil\bld\bde\be (\b(O\bOf\bff\bf)\b)
- If set to o\bon\bn, tilde expansion is performed when readline
+ If set to o\bon\bn, tilde expansion is performed when readline
attempts word completion.
h\bhi\bis\bst\bto\bor\bry\by-\b-p\bpr\bre\bes\bse\ber\brv\bve\be-\b-p\bpo\boi\bin\bnt\bt (\b(O\bOf\bff\bf)\b)
- If set to o\bon\bn, the history code attempts to place point at the
- same location on each history line retrieved with p\bpr\bre\bev\bvi\bio\bou\bus\bs-\b-h\bhi\bis\bs-\b-
+ If set to o\bon\bn, the history code attempts to place point at the
+ same location on each history line retrieved with p\bpr\bre\bev\bvi\bio\bou\bus\bs-\b-h\bhi\bis\bs-\b-
t\bto\bor\bry\by or n\bne\bex\bxt\bt-\b-h\bhi\bis\bst\bto\bor\bry\by.
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,
+ 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
+ becomes longer than the screen width rather than wrapping to a
new line.
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
- will not strip the high bit from the characters it reads),
+ If set to O\bOn\bn, readline will enable eight-bit input (that is, it
+ will not strip the high bit from the characters it reads),
regardless 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.
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)
- 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-
+ 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-
ters _\bE_\bS_\bC and _\bC_\b-_\bJ will terminate an incremental search.
k\bke\bey\bym\bma\bap\bp (\b(e\bem\bma\bac\bcs\bs)\b)
- Set the current readline keymap. The set of valid keymap names
- is _\be_\bm_\ba_\bc_\bs_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bm_\be_\bt_\ba_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx_\b, _\bv_\bi_\b, _\bv_\bi_\b-_\bc_\bo_\bm_\b-
- _\bm_\ba_\bn_\bd, and _\bv_\bi_\b-_\bi_\bn_\bs_\be_\br_\bt. _\bv_\bi is equivalent to _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd; _\be_\bm_\ba_\bc_\bs is
- equivalent to _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd. The default value is _\be_\bm_\ba_\bc_\bs; the
+ Set the current readline keymap. The set of valid keymap names
+ is _\be_\bm_\ba_\bc_\bs_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bm_\be_\bt_\ba_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx_\b, _\bv_\bi_\b, _\bv_\bi_\b-_\bc_\bo_\bm_\b-
+ _\bm_\ba_\bn_\bd, and _\bv_\bi_\b-_\bi_\bn_\bs_\be_\br_\bt. _\bv_\bi is equivalent to _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd; _\be_\bm_\ba_\bc_\bs is
+ equivalent to _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd. The default value is _\be_\bm_\ba_\bc_\bs; the
value of e\bed\bdi\bit\bti\bin\bng\bg-\b-m\bmo\bod\bde\be also affects the default keymap.
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
+ tories have a slash appended (subject to the value of
m\bma\bar\brk\bk-\b-d\bdi\bir\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, unless the leading `.' is supplied by the
+ This variable, when set to O\bOn\bn, causes readline to match files
+ whose names begin with a `.' (hidden files) when performing
+ filename completion, unless the leading `.' is supplied by the
user in the filename to be completed.
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.
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.
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.
+ 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
- common prefix) cause the matches to be listed immediately
+ which have more than one possible completion without any possi-
+ ble partial completion (the possible completions don't share a
+ common prefix) cause the matches to be listed immediately
instead of ringing the bell.
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 extends to the end of the line;
+ $\b$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 extends to the end of the line;
no characters are required to isolate it.
- m\bmo\bod\bde\be The m\bmo\bod\bde\be=\b= form of the $\b$i\bif\bf directive is used to test
- whether readline is in emacs or vi mode. This may be
- used in conjunction with the s\bse\bet\bt k\bke\bey\bym\bma\bap\bp command, for
- instance, to set bindings in the _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd and
- _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx keymaps only if readline is starting out in
+ m\bmo\bod\bde\be The m\bmo\bod\bde\be=\b= form of the $\b$i\bif\bf directive is used to test
+ whether readline is in emacs or vi mode. This may be
+ used in conjunction with the s\bse\bet\bt k\bke\bey\bym\bma\bap\bp command, for
+ instance, to set bindings in the _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd and
+ _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx keymaps only if readline is starting out in
emacs mode.
- t\bte\ber\brm\bm The t\bte\ber\brm\bm=\b= form may be used to include terminal-specific
+ t\bte\ber\brm\bm The t\bte\ber\brm\bm=\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 =\b= is tested against the both 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.
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-
specific settings. Each program using the readline
- library sets the _\ba_\bp_\bp_\bl_\bi_\bc_\ba_\bt_\bi_\bo_\bn _\bn_\ba_\bm_\be, and an initialization
+ library 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
Bash:
$\b$i\bif\bf Bash
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-
+ 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
- line. When the search is terminated, the history entry containing the
+ Escape and Control-J characters will terminate an incremental search.
+ Control-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 Control-S or
- Control-R 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 _\bn_\be_\bw_\bl_\bi_\bn_\be will termi-
+ To find other matching entries in the history list, type Control-S or
+ Control-R 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 _\bn_\be_\bw_\bl_\bi_\bn_\be will termi-
nate the search and accept the line, thereby executing the command from
the history list.
Readline remembers the last incremental search string. If two Control-
- Rs are typed without any intervening characters defining a new search
+ Rs are typed without any intervening characters defining a new search
string, any remembered search string is used.
- Non-incremental searches read the entire search string before starting
- to search for matching history lines. The search string may be typed
+ 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.
R\bRe\bea\bad\bdl\bli\bin\bne\be C\bCo\bom\bmm\bma\ban\bnd\bd N\bNa\bam\bme\bes\bs
- The following is a list of the names of the commands and the default
+ The following is a list of the names of the commands and the default
key sequences to which they are bound. Command names without an accom-
panying key sequence are unbound by default. In the following descrip-
- tions, _\bp_\bo_\bi_\bn_\bt refers to the current cursor position, and _\bm_\ba_\br_\bk refers to
- a cursor position saved by the s\bse\bet\bt-\b-m\bma\bar\brk\bk command. The text between the
+ tions, _\bp_\bo_\bi_\bn_\bt refers to the current cursor position, and _\bm_\ba_\br_\bk refers to
+ a cursor position saved by the s\bse\bet\bt-\b-m\bma\bar\brk\bk command. The text between the
point and mark is referred to as the _\br_\be_\bg_\bi_\bo_\bn.
C\bCo\bom\bmm\bma\ban\bnd\bds\bs f\bfo\bor\br M\bMo\bov\bvi\bin\bng\bg
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).
c\bcl\ble\bea\bar\br-\b-s\bsc\bcr\bre\bee\ben\bn (\b(C\bC-\b-l\bl)\b)
- Clear the screen leaving the current line at the top of the
- screen. With an argument, refresh the current line without
+ Clear the screen leaving the current 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.
C\bCo\bom\bmm\bma\ban\bnd\bds\bs f\bfo\bor\br M\bMa\ban\bni\bip\bpu\bul\bla\bat\bti\bin\bng\bg t\bth\bhe\be H\bHi\bis\bst\bto\bor\bry\by
a\bac\bcc\bce\bep\bpt\bt-\b-l\bli\bin\bne\be (\b(N\bNe\bew\bwl\bli\bin\bne\be,\b, R\bRe\bet\btu\bur\brn\bn)\b)
Accept the line regardless of where the cursor is. If this line
- is non-empty, add it to the history list according to the state
- of the H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL variable. If the line is a modified history
+ is non-empty, add it to the history list according to the state
+ of the H\bHI\bIS\bST\bTC\bCO\bON\bNT\bTR\bRO\bOL\bL variable. If the line is a modified history
line, then restore the history line to its original state.
p\bpr\bre\bev\bvi\bio\bou\bus\bs-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(C\bC-\b-p\bp)\b)
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.
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'
- through the history as necessary. This is an incremental
+ 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'
- through the history as necessary. This is an incremental
+ 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
- between the start of the current line and the point. This is a
+ between the start of the current line and the point. This is a
non-incremental 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
+ insert the _\bnth word from the previous command (the words in the
+ previous command begin with word 0). A negative argument
inserts the _\bnth word from the end of the previous command. Once
- the argument _\bn is computed, the argument is extracted as if the
+ the argument _\bn is computed, the argument is extracted as if the
"!_\bn" history expansion had been specified.
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 an 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 argument
+ Insert the last argument to the previous command (the last word
+ of the previous history entry). With an 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 argument
of each line in turn. The history expansion facilities are used
- to extract the last argument, as if the "!$" history expansion
+ to extract the last argument, as if the "!$" history expansion
had been specified.
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 as the shell does. This performs alias and his-
tory expansion as well as all of the shell word expansions. 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 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
+ Perform history expansion on the current line. 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.
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
- Perform alias expansion on the current line. See A\bAL\bLI\bIA\bAS\bSE\bES\bS above
+ Perform alias expansion on the current line. See A\bAL\bLI\bIA\bAS\bSE\bES\bS above
for a description of alias expansion.
h\bhi\bis\bst\bto\bor\bry\by-\b-a\ban\bnd\bd-\b-a\bal\bli\bia\bas\bs-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-l\bli\bin\bne\be
Perform history and alias expansion on the current line.
i\bin\bns\bse\ber\brt\bt-\b-l\bla\bas\bst\bt-\b-a\bar\brg\bgu\bum\bme\ben\bnt\bt (\b(M\bM-\b-.\b.,\b, M\bM-\b-_\b_)\b)
A synonym for y\bya\ban\bnk\bk-\b-l\bla\bas\bst\bt-\b-a\bar\brg\bg.
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. Any
+ Accept the current line for execution and fetch the next line
+ relative to the current line from the history for editing. Any
argument is ignored.
e\bed\bdi\bit\bt-\b-a\ban\bnd\bd-\b-e\bex\bxe\bec\bcu\but\bte\be-\b-c\bco\bom\bmm\bma\ban\bnd\bd (\b(C\bC-\b-x\bxC\bC-\b-e\be)\b)
- Invoke an editor on the current command line, and execute the
- result as shell commands. B\bBa\bas\bsh\bh attempts to invoke $\b$F\bFC\bCE\bED\bDI\bIT\bT,
+ Invoke an editor on the current command line, and execute the
+ result as shell commands. B\bBa\bas\bsh\bh attempts to invoke $\b$F\bFC\bCE\bED\bDI\bIT\bT,
$\b$E\bED\bDI\bIT\bTO\bOR\bR, and _\be_\bm_\ba_\bc_\bs as the editor, in that order.
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
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 point is at the beginning of
- the line, there are no characters in the line, and the last
+ Delete the character at point. If point is at the beginning of
+ the line, there are no characters in the line, and the last
character typed was not bound to d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br, then return E\bEO\bOF\bF.
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)
- Add the next character typed to the line verbatim. This is how
+ Add the next character typed to the line verbatim. This is how
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)
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
- point, moving point forward as well. If point is at the end of
- the line, then this transposes the two characters before point.
+ Drag the character before point forward over the character at
+ point, moving point forward as well. If point is at the end of
+ the line, then this transposes the two characters before point.
Negative arguments have no effect.
t\btr\bra\ban\bns\bsp\bpo\bos\bse\be-\b-w\bwo\bor\brd\bds\bs (\b(M\bM-\b-t\bt)\b)
- Drag the word before point past the word after point, moving
- point over that word as well. If point is at the end of the
+ Drag the word before point past the word after point, moving
+ point over that word as well. If point is at the end of the
line, this transposes the last two words on the line.
u\bup\bpc\bca\bas\bse\be-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-u\bu)\b)
- Uppercase the current (or following) word. With a negative
+ Uppercase the current (or following) word. With a negative
argument, uppercase the previous word, but do not move point.
d\bdo\bow\bwn\bnc\bca\bas\bse\be-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-l\bl)\b)
- Lowercase the current (or following) word. With a negative
+ Lowercase the current (or following) word. With a negative
argument, lowercase the previous word, but do not move point.
c\bca\bap\bpi\bit\bta\bal\bli\biz\bze\be-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-c\bc)\b)
- Capitalize the current (or following) word. With a negative
+ Capitalize the current (or following) word. With a negative
argument, 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-
- w\bwa\bar\brd\bd-\b-d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br replace the character before point with a
+ 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-
+ w\bwa\bar\brd\bd-\b-d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br replace the character before point with a
space. By default, this command is unbound.
K\bKi\bil\bll\bli\bin\bng\bg a\ban\bnd\bd Y\bYa\ban\bnk\bki\bin\bng\bg
b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-k\bki\bil\bll\bl-\b-l\bli\bin\bne\be (\b(C\bC-\b-x\bx R\bRu\bub\bbo\bou\but\bt)\b)
Kill backward to the beginning of the line.
u\bun\bni\bix\bx-\b-l\bli\bin\bne\be-\b-d\bdi\bis\bsc\bca\bar\brd\bd (\b(C\bC-\b-u\bu)\b)
- Kill backward from point to the beginning of the line. The
+ Kill backward from point to the beginning of the line. The
killed text is saved on the kill-ring.
k\bki\bil\bll\bl-\b-w\bwh\bho\bol\ble\be-\b-l\bli\bin\bne\be
- Kill all characters on the current line, no matter where point
+ Kill all characters on the current line, no matter where point
is.
k\bki\bil\bll\bl-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-d\bd)\b)
- 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
+ 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 those used by f\bfo\bor\brw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd.
b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-k\bki\bil\bll\bl-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-R\bRu\bub\bbo\bou\but\bt)\b)
- Kill the word behind point. Word boundaries are the same as
+ Kill the word behind point. Word boundaries are the same as
those used by b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd.
u\bun\bni\bix\bx-\b-w\bwo\bor\brd\bd-\b-r\bru\bub\bbo\bou\but\bt (\b(C\bC-\b-w\bw)\b)
- Kill the word behind point, using white space as a word bound-
+ Kill the word behind point, using white space as a word bound-
ary. The killed text is saved on the kill-ring.
u\bun\bni\bix\bx-\b-f\bfi\bil\ble\ben\bna\bam\bme\be-\b-r\bru\bub\bbo\bou\but\bt
- Kill the word behind point, using white space and the slash
- character as the word boundaries. The killed text is saved on
+ 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.
d\bde\bel\ble\bet\bte\be-\b-h\bho\bor\bri\biz\bzo\bon\bnt\bta\bal\bl-\b-s\bsp\bpa\bac\bce\be (\b(M\bM-\b-\\b\)\b)
Delete all spaces and tabs around point.
c\bco\bop\bpy\by-\b-r\bre\beg\bgi\bio\bon\bn-\b-a\bas\bs-\b-k\bki\bil\bll\bl
Copy the text in the region to the kill buffer.
c\bco\bop\bpy\by-\b-b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd
- Copy the word before point to the kill buffer. The word bound-
+ Copy the word before point to the kill buffer. The word bound-
aries are the same as b\bba\bac\bck\bkw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd.
c\bco\bop\bpy\by-\b-f\bfo\bor\brw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd
- Copy the word following point to the kill buffer. The word
+ Copy the word following point to the kill buffer. The word
boundaries are the same as f\bfo\bor\brw\bwa\bar\brd\bd-\b-w\bwo\bor\brd\bd.
y\bya\ban\bnk\bk (\b(C\bC-\b-y\by)\b)
Yank the top of the kill ring into the buffer at point.
y\bya\ban\bnk\bk-\b-p\bpo\bop\bp (\b(M\bM-\b-y\by)\b)
- Rotate the kill ring, and yank the new top. Only works follow-
+ Rotate the kill ring, and yank the new top. Only works follow-
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)
- Add this digit to the argument already accumulating, or start a
+ 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
- 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 fol-
- 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
- numeric argument, but is otherwise ignored. As a special case,
- if this command is immediately followed by a character that is
- neither a digit or 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-
+ 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 fol-
+ 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
+ numeric argument, but is otherwise ignored. As a special case,
+ if this command is immediately followed by a character that is
+ neither a digit or 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\bti\bin\bng\bg
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
+ 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.
i\bin\bns\bse\ber\brt\bt-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs (\b(M\bM-\b-*\b*)\b)
- Insert all completions of the text before point that would have
+ Insert all completions of the text before point that would have
been generated by p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs.
m\bme\ben\bnu\bu-\b-c\bco\bom\bmp\bpl\ble\bet\bte\be
- Similar to c\bco\bom\bmp\bpl\ble\bet\bte\be, but replaces the word to be completed with
- a single match from the list of possible completions. Repeated
- execution of m\bme\ben\bnu\bu-\b-c\bco\bom\bmp\bpl\ble\bet\bte\be steps through the list of possible
- completions, inserting each match in turn. At the end of the
+ Similar to c\bco\bom\bmp\bpl\ble\bet\bte\be, but replaces the word to be completed with
+ a single match from the list of possible completions. Repeated
+ execution of m\bme\ben\bnu\bu-\b-c\bco\bom\bmp\bpl\ble\bet\bte\be 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
b\bbe\bel\bll\bl-\b-s\bst\bty\byl\ble\be) and the original text is restored. An argument of _\bn
- moves _\bn 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 T\bTA\bAB\bB, but is unbound by
+ moves _\bn 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 T\bTA\bAB\bB, but is unbound by
default.
d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br-\b-o\bor\br-\b-l\bli\bis\bst\bt
- Deletes the character under the cursor if not at the beginning
- or end of the line (like d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br). If at the end of the
+ Deletes the character under the cursor if not at the beginning
+ or end of the line (like d\bde\bel\ble\bet\bte\be-\b-c\bch\bha\bar\br). If at the end of the
line, behaves identically to p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bns\bs. This command
is unbound by default.
c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-f\bfi\bil\ble\ben\bna\bam\bme\be (\b(M\bM-\b-/\b/)\b)
List the possible completions of the text before point, treating
it as a filename.
c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-u\bus\bse\ber\brn\bna\bam\bme\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
username.
p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-u\bus\bse\ber\brn\bna\bam\bme\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
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
it as a shell variable.
c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-h\bho\bos\bst\btn\bna\bam\bme\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
hostname.
p\bpo\bos\bss\bsi\bib\bbl\ble\be-\b-h\bho\bos\bst\btn\bna\bam\bme\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
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
it as a command name.
d\bdy\byn\bna\bam\bmi\bic\bc-\b-c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-h\bhi\bis\bst\bto\bor\bry\by (\b(M\bM-\b-T\bTA\bAB\bB)\b)
- Attempt completion on the text before point, comparing the text
- against lines from the history list for possible completion
+ Attempt completion on the text before point, comparing the text
+ against lines from the history list for possible completion
matches.
c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-i\bin\bnt\bto\bo-\b-b\bbr\bra\bac\bce\bes\bs (\b(M\bM-\b-{\b{)\b)
Perform filename completion and insert the list of possible com-
- pletions enclosed within braces so the list is available to the
+ pletions enclosed within braces so the list is available to the
shell (see B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn above).
K\bKe\bey\byb\bbo\boa\bar\brd\bd M\bMa\bac\bcr\bro\bos\bs
s\bst\bta\bar\brt\bt-\b-k\bkb\bbd\bd-\b-m\bma\bac\bcr\bro\bo (\b(C\bC-\b-x\bx (\b()\b)
- Begin saving the characters typed into the current keyboard
+ Begin saving the characters typed into the current keyboard
macro.
e\ben\bnd\bd-\b-k\bkb\bbd\bd-\b-m\bma\bac\bcr\bro\bo (\b(C\bC-\b-x\bx )\b))\b)
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.
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-u\bup\bpp\bpe\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 lowercase, run the command that
+ If the metafied character _\bx is lowercase, run the command that
is bound to the corresponding uppercase character.
p\bpr\bre\bef\bfi\bix\bx-\b-m\bme\bet\bta\ba (\b(E\bES\bSC\bC)\b)
Metafy the next character typed. E\bES\bSC\bC f\bf is equivalent to M\bMe\bet\bta\ba-\b-f\bf.
u\bun\bnd\bdo\bo (\b(C\bC-\b-_\b_,\b, C\bC-\b-x\bx C\bC-\b-u\bu)\b)
Incremental undo, separately remembered for each line.
r\bre\bev\bve\ber\brt\bt-\b-l\bli\bin\bne\be (\b(M\bM-\b-r\br)\b)
- Undo all changes made to this line. This is like executing the
- u\bun\bnd\bdo\bo command enough times to return the line to its initial
+ Undo all changes made to this line. This is like executing the
+ u\bun\bnd\bdo\bo command enough times to return the line to its initial
state.
t\bti\bil\bld\bde\be-\b-e\bex\bxp\bpa\ban\bnd\bd (\b(M\bM-\b-&\b&)\b)
Perform tilde expansion on the current word.
s\bse\bet\bt-\b-m\bma\bar\brk\bk (\b(C\bC-\b-@\b@,\b, M\bM-\b-<\b<s\bsp\bpa\bac\bce\be>\b>)\b)
- Set the mark to the point. If a numeric argument is supplied,
+ Set the mark to the point. If a numeric argument is supplied,
the mark is set to that position.
e\bex\bxc\bch\bha\ban\bng\bge\be-\b-p\bpo\boi\bin\bnt\bt-\b-a\ban\bnd\bd-\b-m\bma\bar\brk\bk (\b(C\bC-\b-x\bx C\bC-\b-x\bx)\b)
- Swap the point with the mark. The current cursor position is
- set to the saved position, and the old cursor position is saved
+ 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.
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 count searches for previous occur-
+ that character. A negative count searches for previous occur-
rences.
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 count searches for subse-
+ A character is read and point is moved to the previous occur-
+ rence of that character. A negative count searches for subse-
quent occurrences.
i\bin\bns\bse\ber\brt\bt-\b-c\bco\bom\bmm\bme\ben\bnt\bt (\b(M\bM-\b-#\b#)\b)
- 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
+ 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
- causes this command to make the current line a shell comment.
- If a numeric argument causes the comment character to be
+ 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
+ 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.
g\bgl\blo\bob\bb-\b-c\bco\bom\bmp\bpl\ble\bet\bte\be-\b-w\bwo\bor\brd\bd (\b(M\bM-\b-g\bg)\b)
- 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
+ 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.
g\bgl\blo\bob\bb-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-w\bwo\bor\brd\bd (\b(C\bC-\b-x\bx *\b*)\b)
- 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, an
+ 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, an
asterisk is appended before pathname expansion.
g\bgl\blo\bob\bb-\b-l\bli\bis\bst\bt-\b-e\bex\bxp\bpa\ban\bns\bsi\bio\bon\bns\bs (\b(C\bC-\b-x\bx g\bg)\b)
- The list of expansions that would have been generated by
- g\bgl\blo\bob\bb-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-w\bwo\bor\brd\bd is displayed, and the line is redrawn. If a
- numeric argument is supplied, an asterisk is appended before
+ The list of expansions that would have been generated by
+ g\bgl\blo\bob\bb-\b-e\bex\bxp\bpa\ban\bnd\bd-\b-w\bwo\bor\brd\bd is displayed, and the line is redrawn. If a
+ numeric argument is supplied, an asterisk is appended before
pathname expansion.
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-
+ 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
- the readline output stream. If a numeric argument is supplied,
- the output is formatted in such a way that it can be made part
+ 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 _\bi_\bn_\bp_\bu_\bt_\br_\bc file.
d\bdu\bum\bmp\bp-\b-m\bma\bac\bcr\bro\bos\bs
- Print all of the readline key sequences bound to macros and the
- strings they output. If a numeric argument is supplied, the
+ 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
_\bi_\bn_\bp_\bu_\bt_\br_\bc file.
d\bdi\bis\bsp\bpl\bla\bay\by-\b-s\bsh\bhe\bel\bll\bl-\b-v\bve\ber\brs\bsi\bio\bon\bn (\b(C\bC-\b-x\bx C\bC-\b-v\bv)\b)
- Display version information about the current instance of b\bba\bas\bsh\bh.
+ 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 pro-
+ 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 pro-
grammable completion facilities are invoked.
- First, the command name is identified. If a compspec has been defined
+ 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 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
+ 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.
- 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 filename expansion pattern to the -\b-G\bG
+ Any completions specified by a filename expansion pattern to the -\b-G\bG
option are generated next. The words generated by the pattern need not
- match the word being completed. The G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE shell variable is not
+ match the word being completed. The G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE shell variable is not
used to filter the matches, but the F\bFI\bIG\bGN\bNO\bOR\bRE\bE variable is used.
- Next, the string specified as the argument to the -\b-W\bW option is consid-
- ered. The string is first split using the characters in the I\bIF\bFS\bS spe-
- cial variable as delimiters. Shell quoting is honored. Each word is
- then expanded using brace expansion, tilde expansion, parameter and
- variable expansion, command substitution, and arithmetic expansion, as
+ Next, the string specified as the argument to the -\b-W\bW option is consid-
+ ered. The string is first split using the characters in the I\bIF\bFS\bS spe-
+ cial variable as delimiters. Shell quoting is honored. Each word is
+ then expanded using brace expansion, tilde expansion, parameter and
+ variable expansion, command substitution, and arithmetic expansion, as
described above under E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN. The results are split using the rules
described above under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg. The results of the expansion are
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 is the name of the command whose arguments are being
- completed, the second argument is the word being completed, and the
- third argument is the word preceding the word being completed on the
- current command line. No filtering of the generated completions
- against the word being completed is performed; the function or command
+ 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 is the name of the command whose arguments are being
+ completed, the second argument is the word being completed, and the
+ third argument is the word preceding the word being completed on the
+ current command line. No filtering of the generated completions
+ 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.
- 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.
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
- -\b-o\bo d\bdi\bir\brn\bna\bam\bme\bes\bs option was supplied to c\bco\bom\bmp\bpl\ble\bet\bte\be when the compspec was
+ If the previously-applied actions do not generate any matches, and the
+ -\b-o\bo d\bdi\bir\brn\bna\bam\bme\bes\bs option was supplied to c\bco\bom\bmp\bpl\ble\bet\bte\be when the compspec was
defined, directory name completion is attempted.
- If the -\b-o\bo p\bpl\blu\bus\bsd\bdi\bir\brs\bs option was supplied to c\bco\bom\bmp\bpl\ble\bet\bte\be when the compspec
+ If the -\b-o\bo p\bpl\blu\bus\bsd\bdi\bir\brs\bs option was supplied to c\bco\bom\bmp\bpl\ble\bet\bte\be 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
+ 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,
+ 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,
if attempted, the default b\bba\bas\bsh\bh completions) generate no matches.
- 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 m\bma\bar\brk\bk-\b-d\bdi\bir\bre\bec\bct\bto\bor\bri\bie\bes\bs readline variable, regardless of the
+ 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 m\bma\bar\brk\bk-\b-d\bdi\bir\bre\bec\bct\bto\bor\bri\bie\bes\bs readline variable, regardless of the
setting of the 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 readline variable.
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
+ 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
- above) but after history expansion is performed, subject to the values
+ 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
+ above) but after history expansion is performed, subject to the values
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. When the his-
- tory file is read, lines beginning with the history comment character
- followed immediately by a digit are interpreted as timestamps for the
- preceding history line. These timestamps are optionally displayed
- depending on the value of the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable. When an inter-
- active shell exits, the last $\b$H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE lines are copied from the his-
+ 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. When the his-
+ tory file is read, lines beginning with the history comment character
+ followed immediately by a digit are interpreted as timestamps for the
+ preceding history line. These timestamps are optionally displayed
+ depending on the value of the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable. When an inter-
+ active shell exits, the last $\b$H\bHI\bIS\bST\bTS\bSI\bIZ\bZE\bE lines are copied from the his-
tory 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 over-
- written. If H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is unset, or if the history file is unwritable,
- the history is not saved. If the variable is set, time stamps are
+ are appended to the history file, otherwise the history file is over-
+ written. If H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is unset, or if the history file is unwritable,
+ the history is not saved. If the variable is set, time stamps are
written to the history file, marked with the history comment character,
- so they may be preserved across shell sessions. This uses the history
- comment character to distinguish timestamps 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\bTF\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE is not set, no trunca-
+ so they may be preserved across shell sessions. This uses the history
+ comment character to distinguish timestamps 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\bTF\bFI\bIL\bLE\bES\bSI\bIZ\bZE\bE is not set, no trunca-
tion is performed.
- 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
- manipulate the history file. When using command-line editing, search
- commands are available in each editing mode that provide access to the
+ t\bto\bor\bry\by 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.
- The shell allows control over which commands are saved on the history
+ 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 may be set 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
options.
H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN
- The shell supports a history expansion feature that is similar to the
- history expansion in c\bcs\bsh\bh.\b. This section describes what syntax features
- are available. This feature is enabled by default for interactive
+ The shell supports a history expansion feature that is similar to the
+ history expansion in c\bcs\bsh\bh.\b. This section describes what syntax features
+ are available. This feature is enabled by default for interactive
shells, and can be disabled using the +\b+H\bH 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). Non-interactive shells do not
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.
- History expansion is performed immediately after a complete line is
- read, before the shell breaks it into words. It takes place in two
- parts. The first is to determine which line from the history list to
+ History expansion is performed immediately after a complete line is
+ read, before the shell breaks it into words. It takes place in two
+ parts. The first is to determine which line from the history list to
use during substitution. The second is 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. Various _\bm_\bo_\bd_\bi_\bf_\bi_\be_\br_\bs are available to manipulate the selected
+ is the _\be_\bv_\be_\bn_\bt, and the portions of that line that are acted upon are
+ _\bw_\bo_\br_\bd_\bs. Various _\bm_\bo_\bd_\bi_\bf_\bi_\be_\br_\bs are available to manipulate the selected
words. The line is broken into words in the same fashion as when read-
- ing input, so that several _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br-separated words surrounded by
- quotes are considered one word. History expansions are introduced by
- the appearance of the history expansion character, which is !\b! by
- default. Only backslash (\\b\) and single quotes can quote the history
+ ing input, so that several _\bm_\be_\bt_\ba_\bc_\bh_\ba_\br_\ba_\bc_\bt_\be_\br-separated words surrounded by
+ quotes are considered one word. History expansions are introduced by
+ the appearance of the history expansion character, which is !\b! by
+ default. Only backslash (\\b\) and single quotes can quote the history
expansion character.
- Several characters inhibit history expansion if found immediately fol-
- lowing the history expansion character, even if it is unquoted: space,
- tab, newline, carriage return, and =\b=. If the e\bex\bxt\btg\bgl\blo\bob\bb shell option is
+ Several characters inhibit history expansion if found immediately fol-
+ lowing the history expansion character, even if it is unquoted: space,
+ tab, newline, carriage return, and =\b=. If the e\bex\bxt\btg\bgl\blo\bob\bb shell option is
enabled, (\b( will also inhibit expansion.
- 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
+ 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
option is enabled (see the description of the s\bsh\bho\bop\bpt\bt builtin), and r\bre\bea\bad\bd-\b-
l\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
+ 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 sub-
stitution will be reloaded into the r\bre\bea\bad\bdl\bli\bin\bne\be editing buffer for correc-
- tion. The -\b-p\bp option to the h\bhi\bis\bst\bto\bor\bry\by builtin command may be used to see
+ tion. 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 available for
+ 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 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-
+ 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.
E\bEv\bve\ben\bnt\bt D\bDe\bes\bsi\big\bgn\bna\bat\bto\bor\brs\bs
- An event designator is a reference to a command line entry in the his-
+ An event designator is a reference to a command line entry in the his-
tory list.
- !\b! Start a history substitution, except when followed by a b\bbl\bla\ban\bnk\bk,
- newline, carriage return, = or ( (when the e\bex\bxt\btg\bgl\blo\bob\bb shell option
+ !\b! Start a history substitution, except when followed by a b\bbl\bla\ban\bnk\bk,
+ newline, carriage return, = or ( (when the e\bex\bxt\btg\bgl\blo\bob\bb shell option
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 line minus _\bn.
!\b!_\bs_\bt_\br_\bi_\bn_\bg
Refer to the most recent command starting with _\bs_\bt_\br_\bi_\bn_\bg.
!\b!?\b?_\bs_\bt_\br_\bi_\bn_\bg[\b[?\b?]\b]
- Refer to the most recent command containing _\bs_\bt_\br_\bi_\bn_\bg. The trail-
+ Refer to the most recent command containing _\bs_\bt_\br_\bi_\bn_\bg. The trail-
ing ?\b? may be omitted if _\bs_\bt_\br_\bi_\bn_\bg is followed immediately by a new-
line.
^\b^_\bs_\bt_\br_\bi_\bn_\bg_\b1^\b^_\bs_\bt_\br_\bi_\bn_\bg_\b2^\b^
- Quick substitution. Repeat the last command, replacing _\bs_\bt_\br_\bi_\bn_\bg_\b1
+ Quick substitution. Repeat the last 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/'' (see M\bMo\bod\bd-\b-
i\bif\bfi\bie\ber\brs\bs below).
!\b!#\b# The entire command line typed so far.
W\bWo\bor\brd\bd D\bDe\bes\bsi\big\bgn\bna\bat\bto\bor\brs\bs
- Word designators are used to select desired words from the event. A :\b:
- separates the event specification from the word designator. It may be
- omitted if the word designator begins with a ^\b^, $\b$, *\b*, -\b-, or %\b%. 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 sepa-
+ Word designators are used to select desired words from the event. A :\b:
+ separates the event specification from the word designator. It may be
+ omitted if the word designator begins with a ^\b^, $\b$, *\b*, -\b-, or %\b%. 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 sepa-
rated by single spaces.
0\b0 (\b(z\bze\ber\bro\bo)\b)
$\b$ The last argument.
%\b% The word matched by the most recent `?_\bs_\bt_\br_\bi_\bn_\bg?' search.
_\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$'.
- It is not an error to use *\b* if there is just one word in the
+ *\b* All of the words but the zeroth. This is a synonym for `_\b1_\b-_\b$'.
+ 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 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
+ After the optional word designator, there may appear a sequence of one
or more of the following modifiers, each preceded by a `:'.
h\bh Remove a trailing file name component, leaving only the head.
e\be Remove all but the trailing suffix.
p\bp Print the new command but do not execute it.
q\bq Quote the substituted words, escaping further substitutions.
- x\bx Quote the substituted words as with q\bq, but break into words at
+ x\bx Quote the substituted words as with q\bq, but break into words at
b\bbl\bla\ban\bnk\bks\bs and newlines.
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 delimiter can be used in place 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 sin-
- gle 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 substitu-
+ Substitute _\bn_\be_\bw for the first occurrence of _\bo_\bl_\bd in the event
+ line. Any delimiter can be used in place 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 sin-
+ gle 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 substitu-
tions took place, the last _\bs_\bt_\br_\bi_\bn_\bg in a !\b!?\b?_\bs_\bt_\br_\bi_\bn_\bg[\b[?\b?]\b] search.
&\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
- the final delimiter is optional if it is the last character of
+ 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' modifier once to each word in the event
+ G\bG Apply the following `s\bs' 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
Unless otherwise noted, each builtin command documented in this section
as accepting options preceded by -\b- accepts -\b--\b- to signify the end of the
- options. For example, the :\b:, t\btr\bru\bue\be, f\bfa\bal\bls\bse\be, and t\bte\bes\bst\bt builtins do not
+ options. For example, the :\b:, t\btr\bru\bue\be, f\bfa\bal\bls\bse\be, and t\bte\bes\bst\bt builtins do not
accept options.
:\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. A zero exit code is
+ No effect; the command does nothing beyond expanding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
+ and performing any specified redirections. A zero exit code is
returned.
.\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
- environment and return the exit status of the last command exe-
+ Read and execute commands from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be in the current shell
+ environment 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, file
- names in P\bPA\bAT\bTH\bH are used to find the directory containing _\bf_\bi_\bl_\be_\b-
- _\bn_\ba_\bm_\be. 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, the current directory is
- searched 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_\bm_\be_\bn_\bt_\bs are supplied, they become the posi-
- tional parameters when _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is executed. Otherwise the
- positional parameters are unchanged. 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
+ names in P\bPA\bAT\bTH\bH are used to find the directory containing _\bf_\bi_\bl_\be_\b-
+ _\bn_\ba_\bm_\be. 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, the current directory is
+ searched 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_\bm_\be_\bn_\bt_\bs are supplied, they become the posi-
+ tional parameters when _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is executed. Otherwise the
+ positional parameters are unchanged. 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
+ 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
- returns true unless a _\bn_\ba_\bm_\be is given for which no alias has been
+ 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
+ returns true unless a _\bn_\ba_\bm_\be is given for which no alias has been
defined.
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
+ 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\bV]
b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] -\b-x\bx _\bk_\be_\by_\bs_\be_\bq:_\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
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 _\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
- 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
- appear in _\b._\bi_\bn_\bp_\bu_\bt_\br_\bc, but each binding or command must be passed
- as a separate argument; e.g., '"\C-x\C-r": re-read-init-file'.
+ 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
+ appear in _\b._\bi_\bn_\bp_\bu_\bt_\br_\bc, but each binding or command must be passed
+ as a separate argument; e.g., '"\C-x\C-r": re-read-init-file'.
Options, if supplied, have the following meanings:
-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp
Use _\bk_\be_\by_\bm_\ba_\bp as the keymap to be affected by the subsequent
bindings. Acceptable _\bk_\be_\by_\bm_\ba_\bp names are _\be_\bm_\ba_\bc_\bs_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\b-
- _\bd_\ba_\br_\bd_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bm_\be_\bt_\ba_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx_\b, _\bv_\bi_\b, _\bv_\bi_\b-_\bm_\bo_\bv_\be_\b, _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd,
- and _\bv_\bi_\b-_\bi_\bn_\bs_\be_\br_\bt. _\bv_\bi is equivalent to _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd; _\be_\bm_\ba_\bc_\bs is
+ _\bd_\ba_\br_\bd_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bm_\be_\bt_\ba_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx_\b, _\bv_\bi_\b, _\bv_\bi_\b-_\bm_\bo_\bv_\be_\b, _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd,
+ and _\bv_\bi_\b-_\bi_\bn_\bs_\be_\br_\bt. _\bv_\bi is equivalent to _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd; _\be_\bm_\ba_\bc_\bs is
equivalent to _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd.
-\b-l\bl List the names of all r\bre\bea\bad\bdl\bli\bin\bne\be functions.
- -\b-p\bp Display r\bre\bea\bad\bdl\bli\bin\bne\be function names and bindings in such a
+ -\b-p\bp Display r\bre\bea\bad\bdl\bli\bin\bne\be function names and bindings in such a
way that they can be re-read.
-\b-P\bP List current r\bre\bea\bad\bdl\bli\bin\bne\be function names and bindings.
- -\b-s\bs Display r\bre\bea\bad\bdl\bli\bin\bne\be key sequences bound to macros and the
- strings they output in such a way that they can be re-
+ -\b-s\bs Display r\bre\bea\bad\bdl\bli\bin\bne\be key sequences bound to macros and the
+ strings they output in such a way that they can be re-
read.
- -\b-S\bS Display r\bre\bea\bad\bdl\bli\bin\bne\be key sequences bound to macros and the
+ -\b-S\bS Display r\bre\bea\bad\bdl\bli\bin\bne\be key sequences bound to macros and the
strings they output.
- -\b-v\bv Display r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values in such a way
+ -\b-v\bv Display r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values in such a way
that they can be re-read.
-\b-V\bV List current r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values.
-\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
-\b-r\br _\bk_\be_\by_\bs_\be_\bq
Remove any current binding for _\bk_\be_\by_\bs_\be_\bq.
-\b-x\bx _\bk_\be_\by_\bs_\be_\bq:\b:_\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
- Cause _\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed whenever _\bk_\be_\by_\bs_\be_\bq is
+ Cause _\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed whenever _\bk_\be_\by_\bs_\be_\bq is
entered.
- 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
+ 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
exited. The return value is 0 unless the shell is not executing
a loop when b\bbr\bre\bea\bak\bk is executed.
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-
+ 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\bcd\bd [-\b-L\bL|\b|-\b-P\bP] [_\bd_\bi_\br]
- Change the current directory to _\bd_\bi_\br. The variable H\bHO\bOM\bME\bE is the
- default _\bd_\bi_\br. The variable C\bCD\bDP\bPA\bAT\bTH\bH defines the search path for
- the directory containing _\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., ``.\b.''. If
- _\bd_\bi_\br begins with a slash (/), then C\bCD\bDP\bPA\bAT\bTH\bH is not used. The -\b-P\bP
- option says to use the physical directory structure instead of
- following symbolic links (see also the -\b-P\bP option to the s\bse\bet\bt
+ Change the current directory to _\bd_\bi_\br. The variable H\bHO\bOM\bME\bE is the
+ default _\bd_\bi_\br. The variable C\bCD\bDP\bPA\bAT\bTH\bH defines the search path for
+ the directory containing _\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., ``.\b.''. If
+ _\bd_\bi_\br begins with a slash (/), then C\bCD\bDP\bPA\bAT\bTH\bH is not used. The -\b-P\bP
+ option says to use the physical directory structure instead of
+ following symbolic links (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 fol-
- lowed. An argument of -\b- is equivalent to $\b$O\bOL\bLD\bDP\bPW\bWD\bD. 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 absolute
+ lowed. An argument of -\b- is equivalent to $\b$O\bOL\bLD\bDP\bPW\bWD\bD. 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 absolute
pathname of the new working directory is written to the standard
- output. The return value is true if the directory was success-
+ output. The return value is true if the directory was success-
fully changed; false otherwise.
c\bca\bal\bll\ble\ber\br [_\be_\bx_\bp_\br]
Returns the context of any active subroutine call (a shell func-
- tion or a script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins. With-
+ tion or a script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins. With-
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-
+ 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\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
+ 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
option 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 file name
+ option causes a single word indicating the command or file name
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
+ 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 [_\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
- builtin with the exception of -\b-p\bp and -\b-r\br, and write the matches
- to the standard output. When using the -\b-F\bF or -\b-C\bC options, the
- various shell variables set by the programmable completion
+ 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 exception of -\b-p\bp and -\b-r\br, and write the matches
+ 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 pro-
- grammable completion code had generated them directly from a
+ The matches will be generated in the same way as if the pro-
+ grammable completion code had generated them directly from a
completion specification with the same flags. If _\bw_\bo_\br_\bd is speci-
fied, 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-A\bA _\ba_\bc_\bt_\bi_\bo_\bn] [-\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt] [-\b-W\bW
+ 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-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.]
c\bco\bom\bmp\bpl\ble\bet\bte\be -\b-p\bpr\br [_\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
+ 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-
+ ification for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are supplied, all com-
pletion specifications.
- The process of applying these completion specifications when
- word completion is attempted is described above under P\bPr\bro\bo-\b-
+ The process of applying these completion specifications when
+ word completion is attempted is described above under 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.
- 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
if the compspec generates no matches.
- d\bde\bef\bfa\bau\bul\blt\bt Use readline's default filename completion if
+ d\bde\bef\bfa\bau\bul\blt\bt Use readline's default filename completion if
the compspec generates no matches.
d\bdi\bir\brn\bna\bam\bme\bes\bs
- Perform directory name completion if the comp-
+ Perform directory name completion if the comp-
spec generates no matches.
f\bfi\bil\ble\ben\bna\bam\bme\bes\bs
- Tell readline that the compspec generates file-
- names, so it can perform any filename-specific
- processing (like adding a slash to directory
+ Tell readline that the compspec generates file-
+ names, so it can perform any filename-specific
+ processing (like adding a slash to directory
names or suppressing trailing spaces). Intended
to be used with shell functions.
- n\bno\bos\bsp\bpa\bac\bce\be Tell readline not to append a space (the
- default) to words completed at the end of the
+ n\bno\bos\bsp\bpa\bac\bce\be Tell readline not to append a space (the
+ default) to words completed at the end of the
line.
p\bpl\blu\bus\bsd\bdi\bir\brs\bs
- After any matches defined by the compspec are
- generated, directory name completion is
- attempted and any matches are added to the
+ 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.
-\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.
Names of all shell variables. May also be spec-
ified as -\b-v\bv.
-\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt
- The filename expansion pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
+ The filename expansion pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
generate the possible completions.
-\b-W\bW _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt
- The _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt is split using the characters in the I\bIF\bFS\bS
- 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 com-
+ The _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt is split using the characters in the I\bIF\bFS\bS
+ 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 com-
pleted.
-\b-C\bC _\bc_\bo_\bm_\bm_\ba_\bn_\bd
- _\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed in a subshell environment, and its
+ _\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed in a subshell environment, and its
output is used as the possible completions.
-\b-F\bF _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
- The shell function _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn is executed in the current
- shell environment. 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 shell function _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn is executed in the current
+ shell environment. 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-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 filename expansion.
+ _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for filename 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.
- A leading !\b! in _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt negates the pattern; in this
- case, any completion not matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed.
+ 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.
+ A leading !\b! in _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt negates the pattern; in this
+ case, any completion not matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed.
-\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
other options have been applied.
- The return value is true unless an invalid option is supplied,
- an option other than -\b-p\bp or -\b-r\br is supplied without a _\bn_\ba_\bm_\be argu-
- ment, an attempt is made to remove a completion specification
+ The return value is true unless an invalid option is supplied,
+ an option other than -\b-p\bp or -\b-r\br is supplied without a _\bn_\ba_\bm_\be argu-
+ ment, an attempt is made to remove a completion specification
for a _\bn_\ba_\bm_\be for which no specification exists, or an error occurs
adding a completion specification.
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
- enclosing loops, the last enclosing loop (the ``top-level''
+ 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
+ enclosing loops, the last enclosing loop (the ``top-level''
loop) is resumed. The return value is 0 unless the shell is not
executing a loop when c\bco\bon\bnt\bti\bin\bnu\bue\be is executed.
d\bde\bec\bcl\bla\bar\bre\be [-\b-a\baf\bfF\bFi\bir\brt\btx\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
t\bty\byp\bpe\bes\bse\bet\bt [-\b-a\baf\bfF\bFi\bir\brt\btx\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
- display the attributes and values of each _\bn_\ba_\bm_\be. When -\b-p\bp is
- used, additional options are ignored. The -\b-F\bF option inhibits
- the display of function definitions; only the function name and
+ 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, additional options are ignored. 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 the
- function is defined are displayed as well. The -\b-F\bF option
- implies -\b-f\bf. The following options can be used to restrict out-
- put to variables with the specified attribute or to give vari-
+ using s\bsh\bho\bop\bpt\bt, the source file name and line number where the
+ function is defined are displayed as well. The -\b-F\bF option
+ implies -\b-f\bf. The following options can be used to restrict out-
+ put to variables with the specified attribute or to give vari-
ables attributes:
-\b-a\ba Each _\bn_\ba_\bm_\be is an 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 )\b) is performed when the
+ tion (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN )\b) is performed when the
variable is assigned a value.
-\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
- inherit 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
+ -\b-t\bt Give each _\bn_\ba_\bm_\be the _\bt_\br_\ba_\bc_\be attribute. Traced functions
+ inherit 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-x\bx Mark _\bn_\ba_\bm_\bes for export to subsequent commands via the
+ -\b-x\bx Mark _\bn_\ba_\bm_\bes for export to subsequent commands via the
environment.
- Using `+' instead of `-' turns off the attribute instead, with
+ Using `+' instead of `-' turns off the attribute instead, with
the exceptions that +\b+a\ba may not be used to destroy an array vari-
- able and +\b+r\br w\bwi\bil\bll\bl n\bno\bot\bt r\bre\bem\bmo\bov\bve\be t\bth\bhe\be r\bre\bea\bad\bdo\bon\bnl\bly\by a\bat\btt\btr\bri\bib\bbu\but\bte\be.\b. W\bWh\bhe\ben\bn u\bus\bse\bed\bd
+ able and +\b+r\br w\bwi\bil\bll\bl n\bno\bot\bt r\bre\bem\bmo\bov\bve\be t\bth\bhe\be r\bre\bea\bad\bdo\bon\bnl\bly\by a\bat\btt\btr\bri\bib\bbu\but\bte\be.\b. W\bWh\bhe\ben\bn u\bus\bse\bed\bd
i\bin\bn a\ba f\bfu\bun\bnc\bct\bti\bio\bon\bn,\b, m\bma\bak\bke\bes\bs e\bea\bac\bch\bh _\bn_\ba_\bm_\be l\blo\boc\bca\bal\bl,\b, a\bas\bs w\bwi\bit\bth\bh t\bth\bhe\be l\blo\boc\bca\bal\bl command.
If a variable name is followed by =_\bv_\ba_\bl_\bu_\be, the value of the vari-
- able is set to _\bv_\ba_\bl_\bu_\be. 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 assign a value to an
+ able is set to _\bv_\ba_\bl_\bu_\be. 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 assign a value to an
array variable without using the compound assignment syntax (see
- A\bAr\brr\bra\bay\bys\bs above), one of the _\bn_\ba_\bm_\be_\bs is not a valid shell variable
+ 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 readonly status for a read-
- only variable, an attempt is made to turn off array status for
- an array variable, or an attempt is made to display a non-exis-
+ only variable, an attempt is made to turn off array status for
+ an array variable, or an attempt is made to display a non-exis-
tent function with -\b-f\bf.
d\bdi\bir\brs\bs [\b[+\b+_\bn]\b] [\b[-\b-_\bn]\b] [\b[-\b-c\bcp\bpl\blv\bv]\b]
- Without options, displays the list of currently remembered
- directories. The default display is on a single line with
- directory names separated by spaces. Directories are added to
- the list with the p\bpu\bus\bsh\bhd\bd command; the p\bpo\bop\bpd\bd command removes
+ Without options, displays the list of currently remembered
+ directories. The default display is on a single line with
+ directory names separated by spaces. Directories are added to
+ the list with the p\bpu\bus\bsh\bhd\bd command; the p\bpo\bop\bpd\bd command removes
entries from the list.
+\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.
-\b-c\bc Clears the directory stack by deleting all of the
entries.
- -\b-l\bl Produces a longer listing; the default listing format
+ -\b-l\bl Produces a longer listing; 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.
- The return value is 0 unless an invalid option is supplied or _\bn
+ The return value is 0 unless an invalid option is supplied or _\bn
indexes beyond the end of the directory stack.
d\bdi\bis\bso\bow\bwn\bn [-\b-a\bar\br] [-\b-h\bh] [_\bj_\bo_\bb_\bs_\bp_\be_\bc ...]
- Without options, each _\bj_\bo_\bb_\bs_\bp_\be_\bc is removed from the table of
- active jobs. If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, and neither -\b-a\ba n\bno\bor\br -\b-r\br
- i\bis\bs s\bsu\bup\bpp\bpl\bli\bie\bed\bd,\b, t\bth\bhe\be s\bsh\bhe\bel\bll\bl'\b's\bs n\bno\bot\bti\bio\bon\bn o\bof\bf t\bth\bhe\be _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb i\bis\bs u\bus\bse\bed\bd.\b. I\bIf\bf
+ Without options, each _\bj_\bo_\bb_\bs_\bp_\be_\bc is removed from the table of
+ active jobs. If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, and neither -\b-a\ba n\bno\bor\br -\b-r\br
+ i\bis\bs s\bsu\bup\bpp\bpl\bli\bie\bed\bd,\b, t\bth\bhe\be s\bsh\bhe\bel\bll\bl'\b's\bs n\bno\bot\bti\bio\bon\bn o\bof\bf t\bth\bhe\be _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb i\bis\bs u\bus\bse\bed\bd.\b. I\bIf\bf
t\bth\bhe\be -\b-h\bh o\bop\bpt\bti\bio\bon\bn i\bis\bs g\bgi\biv\bve\ben\bn,\b, e\bea\bac\bch\bh _\bj_\bo_\bb_\bs_\bp_\be_\bc is not removed from the ta-
- ble, but is marked so that S\bSI\bIG\bGH\bHU\bUP\bP is not sent to the job if the
- shell receives a S\bSI\bIG\bGH\bHU\bUP\bP. If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is present, and neither
- the -\b-a\ba nor the -\b-r\br option is supplied, the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used.
+ ble, but is marked so that S\bSI\bIG\bGH\bHU\bUP\bP is not sent to the job if the
+ shell receives a S\bSI\bIG\bGH\bHU\bUP\bP. If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is present, and neither
+ the -\b-a\ba nor the -\b-r\br option is supplied, the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used.
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 argument restricts
- operation to running jobs. The return value is 0 unless a _\bj_\bo_\bb_\b-
+ all jobs; the -\b-r\br option without a _\bj_\bo_\bb_\bs_\bp_\be_\bc argument restricts
+ operation to running jobs. The return value is 0 unless a _\bj_\bo_\bb_\b-
_\bs_\bp_\be_\bc does not specify a valid job.
e\bec\bch\bho\bo [-\b-n\bne\beE\bE] [_\ba_\br_\bg ...]
- Output the _\ba_\br_\bgs, separated by spaces, followed by a newline.
+ Output the _\ba_\br_\bgs, separated by spaces, followed by a newline.
The return status is always 0. If -\b-n\bn is specified, the trailing
- newline is suppressed. If the -\b-e\be option is given, interpreta-
- tion of the following backslash-escaped characters is enabled.
- The -\b-E\bE option disables the interpretation of these escape char-
- acters, 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 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
+ newline is suppressed. If the -\b-e\be option is given, interpreta-
+ tion of the following backslash-escaped characters is enabled.
+ The -\b-E\bE option disables the interpretation of these escape char-
+ acters, 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 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:
\\b\a\ba alert (bell)
\\b\b\bb backspace
\\b\t\bt horizontal tab
\\b\v\bv vertical tab
\\b\\\b\ backslash
- \\b\0\b0_\bn_\bn_\bn the eight-bit character whose value is the octal value
+ \\b\0\b0_\bn_\bn_\bn the eight-bit character whose value is the octal value
_\bn_\bn_\bn (zero 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)
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
+ 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
+ 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
enabled. 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
+ 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.
- The -\b-d\bd option will delete a builtin previously loaded with -\b-f\bf.
+ 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. The return
- value is 0 unless a _\bn_\ba_\bm_\be is not a shell builtin or there is an
+ 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. 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
+ ning of the zeroth argument passed to _\bc_\bo_\bm_\bm_\ba_\bn_\bd. This is what
_\bl_\bo_\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
+ 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 shell option e\bex\bxe\bec\bcf\bfa\bai\bil\bl is enabled, in which case it
- returns failure. An interactive shell returns failure if the
+ not be executed for some reason, a non-interactive shell exits,
+ unless the shell option e\bex\bxe\bec\bcf\bfa\bai\bil\bl is enabled, in which case it
+ returns failure. An interactive shell returns failure if the
file cannot be executed. If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is not specified, any redi-
rections take effect in the current shell, and the return status
- is 0. If there is a redirection error, the return status is 1.
+ 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.
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 all names that are
- exported in this shell 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 of the _\bn_\ba_\bm_\be_\bs is not a valid shell
+ 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 all names that are
+ exported in this shell 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 of the _\bn_\ba_\bm_\be_\bs is not a valid shell
variable name, or -\b-f\bf is supplied with a _\bn_\ba_\bm_\be that is not a func-
tion.
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]
- Fix Command. In the first form, a range of commands from _\bf_\bi_\br_\bs_\bt
- to _\bl_\ba_\bs_\bt is selected from the history list. _\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
+ Fix Command. In the first form, a range of commands from _\bf_\bi_\br_\bs_\bt
+ to _\bl_\ba_\bs_\bt is selected from the history list. _\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 cur-
rent command number). If _\bl_\ba_\bs_\bt is not specified it is set to the
- current command for listing (so that ``fc -l -10'' prints 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 spec-
- ified it is set to the previous command for editing and -16 for
+ 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
- is given, the commands are listed on standard output. Other-
- wise, the editor given by _\be_\bn_\ba_\bm_\be is invoked on a file containing
- those commands. If _\be_\bn_\ba_\bm_\be is not given, the value of the F\bFC\bCE\bED\bDI\bIT\bT
- variable is used, and the value of E\bED\bDI\bIT\bTO\bOR\bR if F\bFC\bCE\bED\bDI\bIT\bT is not set.
- If neither variable is set, _\bv_\bi is used. When editing is com-
+ 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
+ is given, the commands are listed on standard output. Other-
+ wise, the editor given by _\be_\bn_\ba_\bm_\be is invoked on a file containing
+ those commands. If _\be_\bn_\ba_\bm_\be is not given, the value of the F\bFC\bCE\bED\bDI\bIT\bT
+ variable is used, and the value of E\bED\bDI\bIT\bTO\bOR\bR if F\bFC\bCE\bED\bDI\bIT\bT is not set.
+ If neither variable is set, _\bv_\bi is used. When editing is com-
plete, the edited commands are echoed and executed.
- 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. A useful alias to use with this is
- ``r="fc -s"'', so that typing ``r cc'' runs the last command
+ 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. 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 com-
mand.
- If the first form is used, the return value is 0 unless an
- invalid option is encountered or _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt specify history
- lines out of range. If the -\b-e\be option is supplied, the return
+ If the first form is used, the return value is 0 unless an
+ invalid option is encountered or _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt specify history
+ lines out of range. If the -\b-e\be option is supplied, the return
value is the value of the last command executed or failure if an
error occurs with the temporary file of commands. If the second
- form is used, the return status is that of the command re-exe-
- cuted, unless _\bc_\bm_\bd does not specify a valid history line, in
+ form is used, the return status is that of the command re-exe-
+ cuted, unless _\bc_\bm_\bd does not specify a valid history line, in
which case f\bfc\bc returns failure.
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.
+ 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
+ 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_\bs]
- 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
- expected 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
+ 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
+ expected 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
_\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
- option requires an argument, g\bge\bet\bto\bop\bpt\bts\bs places that argument into
- the variable O\bOP\bPT\bTA\bAR\bRG\bG. The shell does not reset O\bOP\bPT\bTI\bIN\bND\bD automati-
- cally; it must be manually reset between multiple calls to
+ 1 each time the shell or a shell script is invoked. When an
+ option requires an argument, g\bge\bet\bto\bop\bpt\bts\bs places that argument into
+ the variable O\bOP\bPT\bTA\bAR\bRG\bG. The shell does not reset O\bOP\bPT\bTI\bIN\bND\bD automati-
+ cally; it must be manually reset between multiple calls to
g\bge\bet\bto\bop\bpt\bts\bs within the same shell invocation if a new set of parame-
ters is to be used.
- When the end of options is encountered, g\bge\bet\bto\bop\bpt\bts\bs exits with a
- return value greater than zero. O\bOP\bPT\bTI\bIN\bND\bD is set to the index of
+ When the end of options is encountered, g\bge\bet\bto\bop\bpt\bts\bs exits with a
+ return value greater than zero. O\bOP\bPT\bTI\bIN\bND\bD is set to the index of
the first non-option argument, and n\bna\bam\bme\be is set to ?.
- g\bge\bet\bto\bop\bpt\bts\bs normally parses the positional parameters, but if more
+ g\bge\bet\bto\bop\bpt\bts\bs normally parses the positional parameters, but if more
arguments are given in _\ba_\br_\bg_\bs, g\bge\bet\bto\bop\bpt\bts\bs parses those instead.
- g\bge\bet\bto\bop\bpt\bts\bs can report errors in two ways. If the first character
- of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is a colon, _\bs_\bi_\bl_\be_\bn_\bt error reporting is used. In
- normal operation diagnostic messages are printed when invalid
- options or missing option arguments are encountered. If the
- variable O\bOP\bPT\bTE\bER\bRR\bR is set to 0, no error messages will be dis-
+ g\bge\bet\bto\bop\bpt\bts\bs can report errors in two ways. If the first character
+ of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is a colon, _\bs_\bi_\bl_\be_\bn_\bt error reporting is used. In
+ normal operation diagnostic messages are printed when invalid
+ options or missing option arguments are encountered. If the
+ 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
+ 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\bPT\bTA\bAR\bRG\bG and no diagnostic message is printed.
- 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,
+ 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
character found.
- g\bge\bet\bto\bop\bpt\bts\bs returns true if an option, specified or unspecified, is
+ g\bge\bet\bto\bop\bpt\bts\bs returns true if an option, specified or unspecified, is
found. It returns false if the end of options is encountered or
an error occurs.
h\bha\bas\bsh\bh [-\b-l\blr\br] [-\b-p\bp _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be] [-\b-d\bdt\bt] [_\bn_\ba_\bm_\be]
- For each _\bn_\ba_\bm_\be, the full file name of the command is determined
+ For each _\bn_\ba_\bm_\be, the full file name of the command is determined
by searching the directories in $\b$P\bPA\bAT\bTH\bH and remembered. If the -\b-p\bp
option is supplied, no path search is performed, and _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is
used as the full file name of the command. The -\b-r\br option causes
- the shell to forget all remembered locations. The -\b-d\bd option
+ the shell to forget all remembered locations. 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
+ 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 causes output to be displayed in a for-
- mat that may be reused as input. If no arguments are given, or
+ mat that may be reused as input. If no arguments are given, or
if only -\b-l\bl is supplied, information about remembered commands is
- printed. The return status is true unless a _\bn_\ba_\bm_\be is not found
+ printed. 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-s\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
- structures is printed. The -\b-s\bs option restricts the information
- displayed to a short usage synopsis. The return status is 0
+ 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. The -\b-s\bs option restricts the information
+ displayed to a short usage synopsis. The return status is 0
unless no command matches _\bp_\ba_\bt_\bt_\be_\br_\bn.
h\bhi\bis\bst\bto\bor\bry\by [\b[_\bn]\b]
h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
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-
- F\bFO\bOR\bRM\bMA\bAT\bT is set and not null, it is used as a format string for
- _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3) to display the time stamp associated with each dis-
- played history entry. No intervening blank is printed between
- the formatted time stamp and the history line. If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is
- supplied, it is used as the name of the history file; if not,
- the value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is used. Options, if supplied, have the
+ _\bn lists only the last _\bn lines. If the shell variable H\bHI\bIS\bST\bTT\bTI\bIM\bME\bE-\b-
+ F\bFO\bOR\bRM\bMA\bAT\bT is set and not null, it is used as a format string for
+ _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3) to display the time stamp associated with each dis-
+ played history entry. No intervening blank is printed between
+ the formatted time stamp and the history line. If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is
+ supplied, it is used as the name of the history file; if not,
+ the value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is used. Options, if supplied, have the
following meanings:
-\b-c\bc Clear the history list by deleting all the entries.
-\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
Delete the history entry at position _\bo_\bf_\bf_\bs_\be_\bt.
- -\b-a\ba Append the ``new'' history lines (history lines entered
- since the beginning of the current b\bba\bas\bsh\bh session) to the
+ -\b-a\ba Append the ``new'' history lines (history lines entered
+ since the beginning of the current b\bba\bas\bsh\bh session) 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
- appended 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
+ appended 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 use them as the
current history.
- -\b-w\bw Write the current history to the history file, overwrit-
+ -\b-w\bw Write the current history to the history file, overwrit-
ing 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 is set, the time stamp information associ-
- ated with each history entry is written to the history file,
- marked with the history comment character. When the history
+ ated 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 previous history line. 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 is supplied as an
+ followed immediately by a digit are interpreted as timestamps
+ for the previous history line. 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 is supplied as an
argument to -\b-d\bd, or the history expansion supplied as an argument
to -\b-p\bp fails.
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-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-n\bn Display information only about jobs that have changed
- status since the user was last notified of their status.
+ -\b-n\bn Display information only about jobs that have changed
+ status since the user was last notified of their status.
-\b-r\br Restrict output to running jobs.
-\b-s\bs Restrict output to 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
- _\bc_\bo_\bm_\bm_\ba_\bn_\bd or _\ba_\br_\bg_\bs with the corresponding process group ID, and
+ _\bc_\bo_\bm_\bm_\ba_\bn_\bd or _\ba_\br_\bg_\bs with the corresponding process group ID, and
executes _\bc_\bo_\bm_\bm_\ba_\bn_\bd passing it _\ba_\br_\bg_\bs, returning its exit status.
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 [_\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. k\bki\bil\bll\bl returns true
- if at least one signal was successfully sent, or false if an
+ -\b-l\bl is a number specifying either a signal number or the exit
+ status of a process terminated by a signal. k\bki\bil\bll\bl returns true
+ if at least one signal was successfully sent, or false if an
error occurs or an invalid option 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). If the last _\ba_\br_\bg evaluates to 0, l\ble\bet\bt returns
+ M\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN). 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-
+ variable _\bn_\ba_\bm_\be to have a visible scope restricted to that func-
tion and its children. 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
+ 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.
p\bpo\bop\bpd\bd [-n\bn] [+_\bn] [-_\bn]
- Removes entries from the directory stack. With no arguments,
- removes the top directory from the stack, and performs a c\bcd\bd to
+ Removes entries from the directory stack. With no arguments,
+ removes the top directory from the stack, and performs a c\bcd\bd to
the new top directory. Arguments, if supplied, have the follow-
ing meanings:
- -\b-n\bn Suppresses the normal change of directory when removing
- directories from the stack, so that only the stack is
+ -\b-n\bn Suppresses the normal change of directory when removing
+ directories from the stack, so that only the stack is
manipulated.
- +\b+_\bn Removes the _\bnth entry counting from the left of the list
- shown by d\bdi\bir\brs\bs, starting with zero. For example: ``popd
+ +\b+_\bn Removes the _\bnth entry counting from the left of the list
+ shown by d\bdi\bir\brs\bs, starting with zero. For 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 p\bpo\bop\bpd\bd command is successful, a d\bdi\bir\brs\bs is performed as well,
- and the return status is 0. p\bpo\bop\bpd\bd returns false if an invalid
+ If the p\bpo\bop\bpd\bd command is successful, a d\bdi\bir\brs\bs is performed as well,
+ and the return status is 0. p\bpo\bop\bpd\bd returns false if an invalid
option is encountered, the directory stack is empty, a non-exis-
tent directory stack entry is specified, or the directory change
fails.
p\bpr\bri\bin\bnt\btf\bf [-\b-v\bv _\bv_\ba_\br] _\bf_\bo_\br_\bm_\ba_\bt [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
- Write the formatted _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs to the standard output under the
- control of the _\bf_\bo_\br_\bm_\ba_\bt. The _\bf_\bo_\br_\bm_\ba_\bt 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 for-
- mat specifications, each of which causes printing of the next
+ Write the formatted _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs to the standard output under the
+ control of the _\bf_\bo_\br_\bm_\ba_\bt. The _\bf_\bo_\br_\bm_\ba_\bt 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 for-
+ mat specifications, each of which causes printing of the next
successive _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt. In addition to the standard _\bp_\br_\bi_\bn_\bt_\bf(1) for-
- mats, %\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 (except that \\b\c\bc terminates output,
+ mats, %\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 (except that \\b\c\bc terminates output,
backslashes in \\b\'\b', \\b\"\b", and \\b\?\b? are not removed, and octal escapes
- beginning with \\b\0\b0 may contain up to four digits), and %\b%q\bq causes
+ beginning with \\b\0\b0 may contain up to four digits), and %\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.
- The -\b-v\bv option causes the output to be assigned to the variable
+ The -\b-v\bv option causes the output to be assigned to the variable
_\bv_\ba_\br rather than being printed to the standard output.
- 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
+ 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, non-zero on failure.
p\bpu\bus\bsh\bhd\bd [-\b-n\bn] [+_\bn] [-_\bn]
p\bpu\bus\bsh\bhd\bd [-\b-n\bn] [_\bd_\bi_\br]
- Adds a directory to the top of the directory stack, or rotates
- the stack, making the new top of the stack the current working
+ 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, exchanges the top two directories
- and returns 0, unless the directory stack is empty. Arguments,
+ and returns 0, unless the directory stack is empty. Arguments,
if supplied, have the following meanings:
- -\b-n\bn Suppresses the normal change of directory when adding
- directories to the stack, so that only the stack is
+ -\b-n\bn Suppresses the normal change of directory when adding
+ directories to the stack, so that only the stack is
manipulated.
- +\b+_\bn Rotates the stack so that the _\bnth directory (counting
- from the left of the list shown by d\bdi\bir\brs\bs, starting with
+ +\b+_\bn Rotates the stack so that the _\bnth directory (counting
+ from the left of the list shown by d\bdi\bir\brs\bs, starting with
zero) is at the top.
- -\b-_\bn Rotates the stack so that the _\bnth directory (counting
- from the right of the list shown by d\bdi\bir\brs\bs, starting with
+ -\b-_\bn Rotates the stack so that the _\bnth directory (counting
+ from the right of the list shown by d\bdi\bir\brs\bs, starting with
zero) is at the top.
_\bd_\bi_\br Adds _\bd_\bi_\br to the directory stack at the top, making it the
new current working directory.
If the p\bpu\bus\bsh\bhd\bd command is successful, a d\bdi\bir\brs\bs is performed as well.
- If the first form is used, p\bpu\bus\bsh\bhd\bd returns 0 unless the cd to _\bd_\bi_\br
- fails. With the second form, p\bpu\bus\bsh\bhd\bd returns 0 unless the direc-
- tory stack is empty, a non-existent directory stack element is
- specified, or the directory change to the specified new current
+ If the first form is used, p\bpu\bus\bsh\bhd\bd returns 0 unless the cd to _\bd_\bi_\br
+ fails. With the second form, p\bpu\bus\bsh\bhd\bd returns 0 unless the direc-
+ tory stack is empty, a non-existent directory stack element is
+ specified, or the directory change to the specified new current
directory fails.
p\bpw\bwd\bd [-\b-L\bLP\bP]
- Print the absolute pathname of the current working directory.
+ Print the absolute pathname of the current working directory.
The pathname printed contains no symbolic links if the -\b-P\bP option
is supplied or the -\b-o\bo p\bph\bhy\bys\bsi\bic\bca\bal\bl option to the s\bse\bet\bt builtin command
- is enabled. If the -\b-L\bL option is used, the pathname printed may
- contain symbolic links. The return status is 0 unless an error
- occurs while reading the name of the current directory or an
+ is enabled. If the -\b-L\bL option is used, the pathname printed may
+ contain symbolic links. The return status is 0 unless an error
+ occurs while reading the name of the current directory or an
invalid option is supplied.
- r\bre\bea\bad\bd [-\b-e\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\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]
+ r\bre\bea\bad\bd [-\b-e\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\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
- descriptor _\bf_\bd supplied as an argument to the -\b-u\bu option, and the
+ One line is read from the standard input, or from the file
+ descriptor _\bf_\bd supplied as an argument to the -\b-u\bu option, 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, with leftover words and their interven-
- ing separators assigned to the last _\bn_\ba_\bm_\be. If there are fewer
+ second _\bn_\ba_\bm_\be, and so on, with leftover words and their interven-
+ ing separators 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 values. The characters in I\bIF\bFS\bS are used to
- split the line into words. The backslash character (\\b\) may be
- used to remove any special meaning for the next character read
- and for line continuation. Options, if supplied, have the fol-
+ are assigned empty values. The characters in I\bIF\bFS\bS are used to
+ split the line into words. The backslash character (\\b\) may be
+ used to remove any special meaning for the next character read
+ and for line continuation. Options, if supplied, have the fol-
lowing meanings:
-\b-a\ba _\ba_\bn_\ba_\bm_\be
The words are assigned to sequential indices of the array
new values are assigned. Other _\bn_\ba_\bm_\be arguments are
ignored.
-\b-d\bd _\bd_\be_\bl_\bi_\bm
- The first character of _\bd_\be_\bl_\bi_\bm is used to terminate the
+ The first character of _\bd_\be_\bl_\bi_\bm is used to terminate the
input line, rather than newline.
-\b-e\be If the standard input is coming from a terminal, r\bre\bea\bad\bdl\bli\bin\bne\be
(see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE above) is used to obtain the line.
-\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.
-\b-p\bp _\bp_\br_\bo_\bm_\bp_\bt
Display _\bp_\br_\bo_\bm_\bp_\bt on standard error, without a trailing new-
line, before attempting to read any input. The prompt is
displayed only if input is coming from a terminal.
-\b-r\br Backslash does not act as an escape character. The back-
- slash is considered to be part of the line. In particu-
- lar, a backslash-newline pair may not be used as a line
+ slash is considered to be part of the line. In particu-
+ lar, a backslash-newline pair may not be used as a line
continuation.
-\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 is not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. This
- option has no effect if r\bre\bea\bad\bd is not reading input from
+ Cause r\bre\bea\bad\bd to time out and return failure if a complete
+ line of input is not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. This
+ option has no effect if r\bre\bea\bad\bd is not reading input from
the terminal or a pipe.
-\b-u\bu _\bf_\bd Read input from file descriptor _\bf_\bd.
If no _\bn_\ba_\bm_\be_\bs are supplied, the line read is assigned to the vari-
- able R\bRE\bEP\bPL\bLY\bY. The return code is zero, unless end-of-file is
- encountered, r\bre\bea\bad\bd times out, or an invalid file descriptor is
+ able R\bRE\bEP\bPL\bLY\bY. The return code is zero, unless end-of-file is
+ encountered, r\bre\bea\bad\bd times out, or an invalid file descriptor is
supplied as the argument to -\b-u\bu.
r\bre\bea\bad\bdo\bon\bnl\bly\by [-\b-a\bap\bpf\bf] [_\bn_\ba_\bm_\be[=_\bw_\bo_\br_\bd] ...]
- The given _\bn_\ba_\bm_\be_\bs are marked readonly; the values of these _\bn_\ba_\bm_\be_\bs
- may not be changed by subsequent assignment. If the -\b-f\bf option
- is supplied, the functions corresponding to the _\bn_\ba_\bm_\be_\bs are so
+ The given _\bn_\ba_\bm_\be_\bs are marked readonly; the values of these _\bn_\ba_\bm_\be_\bs
+ may not be changed by subsequent assignment. If the -\b-f\bf option
+ is supplied, the functions corresponding to the _\bn_\ba_\bm_\be_\bs are so
marked. The -\b-a\ba option restricts the variables to arrays. If no
- _\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 -\b-p\bp option causes
- output to be displayed in a format that may be reused as input.
- If a variable name is followed by =_\bw_\bo_\br_\bd, the value of the vari-
- able is set to _\bw_\bo_\br_\bd. The return status is 0 unless an invalid
- option is encountered, one of the _\bn_\ba_\bm_\be_\bs is not a valid shell
+ _\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 -\b-p\bp option causes
+ output to be displayed in a format that may be reused as input.
+ If a variable name is followed by =_\bw_\bo_\br_\bd, the value of the vari-
+ able is set to _\bw_\bo_\br_\bd. The return status is 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 supplied with a _\bn_\ba_\bm_\be that is not a func-
tion.
r\bre\bet\btu\bur\brn\bn [_\bn]
- Causes a function to exit with the return value specified by _\bn.
- If _\bn is omitted, the return status is that of the last command
- executed in the function body. If used outside a function, but
- during execution of a script by the .\b. (s\bso\bou\bur\brc\bce\be) command, it
+ Causes a function to exit with the return value specified by _\bn.
+ If _\bn is omitted, the return status is that of the last command
+ executed in the function body. If used outside a function, but
+ during execution of a script by the .\b. (s\bso\bou\bur\brc\bce\be) command, it
causes the shell to stop executing 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 used outside a
- function and not during execution of a script by .\b., the return
+ _\bn or the exit status of the last command executed within the
+ script as the exit status of the script. If used outside a
+ function and not during execution of a script by .\b., the return
status is false. Any command associated with the R\bRE\bET\bTU\bUR\bRN\bN trap is
- executed before execution resumes after the function or script.
+ executed before execution resumes after the function or script.
s\bse\bet\bt [-\b--\b-a\bab\bbe\bef\bfh\bhk\bkm\bmn\bnp\bpt\btu\buv\bvx\bxB\bBC\bCE\bEH\bHP\bPT\bT] [-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [_\ba_\br_\bg ...]
s\bse\bet\bt [+\b+a\bab\bbe\bef\bfh\bhk\bkm\bmn\bnp\bpt\btu\buv\bvx\bxB\bBC\bCE\bEH\bHP\bPT\bT] [+\b+o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [_\ba_\br_\bg ...]
- Without options, the name and value of each shell variable are
+ Without options, the name and value of each shell variable are
displayed in a format that can be reused as input for setting or
resetting the currently-set variables. Read-only variables can-
- not 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
- arguments remaining after the options are processed are treated
- as values for the positional parameters and are assigned, in
+ not 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
+ arguments remaining after the options are processed 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 fol-
lowing meanings:
- -\b-a\ba Automatically mark variables and functions which are
- modified or created for export to the environment of
+ -\b-a\ba Automatically mark variables and functions which are
+ modified or created 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 _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR
+ -\b-e\be Exit immediately if a _\bs_\bi_\bm_\bp_\bl_\be _\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 in an i\bif\bf statement, part of a &\b&&\b& or |\b||\b|
- list, any command in a pipeline but the last, or if the
- command's return value is being inverted via !\b!. A trap
+ 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 in an i\bif\bf statement, part of a &\b&&\b& or |\b||\b|
+ list, any command in a pipeline but the last, or if the
+ command's return value is being inverted via !\b!. A trap
on E\bER\bRR\bR, if set, is executed before the shell exits.
-\b-f\bf Disable pathname expansion.
- -\b-h\bh Remember the location of commands as they are looked up
+ -\b-h\bh Remember the location of commands as they are looked up
for execution. This is enabled by default.
- -\b-k\bk All arguments in the form of assignment statements are
- placed in the environment for a command, not just those
+ -\b-k\bk All arguments in the form of assignment statements are
+ placed in the environment for a command, not just those
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 above). Background pro-
- cesses run in a separate process group and a line con-
- taining their exit status is printed upon their comple-
+ -\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 above). Background pro-
+ cesses run in a separate process group and a line con-
+ taining their exit status is printed upon their comple-
tion.
-\b-n\bn Read commands but do not execute them. This may be used
- to check a shell script for syntax errors. This is
+ to check a shell script for syntax errors. This is
ignored 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.
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
- ``IGNOREEOF=10'' had been executed (see S\bSh\bhe\bel\bll\bl
+ 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.
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
+ 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).
p\bpr\bri\biv\bvi\bil\ble\beg\bge\bed\bd
Same as -\b-p\bp.
v\bvi\bi Use a vi-style command line editing interface.
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, the values of the
- current options are printed. If +\b+o\bo is supplied with no
- _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, a series of s\bse\bet\bt commands to recreate the
- current option settings is displayed on the standard
+ current options are printed. If +\b+o\bo is supplied with no
+ _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, a series of s\bse\bet\bt commands to recreate the
+ current option settings is displayed 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
- variable, if it appears in the environment, is 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 supplied, these actions are taken and the
+ -\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
+ variable, if it appears in the environment, is 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 supplied, these actions are taken and the
effective user id is set to the real user id. If the -\b-p\bp
- option is supplied at startup, the effective user id is
+ 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
+ user and group ids to be set to the real user and group
ids.
-\b-t\bt Exit after reading and executing one command.
-\b-u\bu Treat unset variables as an error when performing param-
- eter expansion. If expansion is attempted on an unset
+ eter expansion. If expansion is attempted on an unset
variable, the shell prints an error message, and, if not
interactive, 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
+ play the expanded value of P\bPS\bS4\b4, followed by the command
and its expanded arguments or associated word list.
- -\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.
- -\b-P\bP If set, the shell does not follow symbolic links when
- executing commands such as c\bcd\bd that change the current
+ -\b-P\bP If set, the shell does not follow 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
+ 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
- executed in a subshell environment. The D\bDE\bEB\bBU\bUG\bG and
+ -\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
+ executed 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
+ 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
- options can also be specified as arguments to an invocation of
- the shell. The current set of options may be found in $\b$-\b-. The
+ The options are off by default unless otherwise noted. Using +
+ rather than - causes these options to be turned off. The
+ options can also be specified as arguments to an invocation of
+ the shell. The current set of options may be found in $\b$-\b-. The
return 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
- unset. _\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
- parameters are not changed. The return status is greater than
+ 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
+ unset. _\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
+ parameters 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 variables controlling optional shell behav-
ior. With no options, or with the -\b-p\bp option, a list of all set-
table options is displayed, with an indication of whether or not
- each is set. The -\b-p\bp option causes output to be displayed in a
- form that may be reused as input. Other options have the fol-
+ each is set. The -\b-p\bp option causes output to be displayed in a
+ form that may be reused as input. Other options have the fol-
lowing 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-
+ 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, the dis-
+ If either -\b-s\bs or -\b-u\bu is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, the dis-
play is limited to those options which are set or unset, respec-
- tively. Unless otherwise noted, the s\bsh\bho\bop\bpt\bt options are disabled
+ tively. 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
- options, 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
+ options, 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\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
+ 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 file name 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 file name 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-
- 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, bash 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 above). The shell always postpones
+ 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
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 command
- and, if necessary, updates the values of L\bLI\bIN\bNE\bES\bS and C\bCO\bOL\bL-\b-
+ If set, b\bba\bas\bsh\bh checks the window size after each command
+ and, if necessary, updates the values of L\bLI\bIN\bNE\bES\bS and C\bCO\bOL\bL-\b-
U\bUM\bMN\bNS\bS.
- c\bcm\bmd\bdh\bhi\bis\bst\bt If set, b\bba\bas\bsh\bh attempts to save all lines of a multiple-
- line command in the same history entry. This allows
+ c\bcm\bmd\bdh\bhi\bis\bst\bt If set, b\bba\bas\bsh\bh attempts to save all lines of a multiple-
+ line command in the same history entry. This allows
easy re-editing of multi-line commands.
- d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a `.' in
+ 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.
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, behavior intended for use by debuggers is
+ If set, 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), a call to
+ 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), a call to
r\bre\bet\btu\bur\brn\bn is simulated.
- 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.
- 6\b6.\b. Error tracing is enabled: command substitution,
- shell functions, and subshells invoked with (\b(
+ 6\b6.\b. Error tracing is enabled: command substitution,
+ shell functions, and subshells invoked with (\b(
_\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the E\bER\bRR\bRO\bOR\bR trap.
e\bex\bxt\btg\bgl\blo\bob\bb If set, the extended pattern matching features described
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
- description of F\bFI\bIG\bGN\bNO\bOR\bRE\bE. This option is enabled by
+ description of F\bFI\bIG\bGN\bNO\bOR\bRE\bE. This option is enabled by
default.
g\bgn\bnu\bu_\b_e\ber\brr\brf\bfm\bmt\bt
If set, shell error messages are written in the standard
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
- by the value of the H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE variable when the shell
+ 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
exits, 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
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\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
+ 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
option is enabled by default.
- l\bli\bit\bth\bhi\bis\bst\bt If set, and the c\bcm\bmd\bdh\bhi\bis\bst\bt option is enabled, multi-line
+ l\bli\bit\bth\bhi\bis\bst\bt If set, and the c\bcm\bmd\bdh\bhi\bis\bst\bt option is enabled, multi-line
commands are saved to the history with embedded newlines
rather than using semicolon separators where possible.
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 above). The value may not be
+ 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 above). 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-
+ 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.
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
+ If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will not
attempt to search the P\bPA\bAT\bTH\bH for possible completions when
completion is attempted on an empty line.
n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb
- If set, b\bba\bas\bsh\bh matches filenames in a case-insensitive
+ 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 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.
n\bnu\bul\bll\blg\bgl\blo\bob\bb
- If set, b\bba\bas\bsh\bh allows 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 above) to expand to a null string,
+ If set, b\bba\bas\bsh\bh allows 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 above) to expand to a null string,
rather than themselves.
p\bpr\bro\bog\bgc\bco\bom\bmp\bp
If set, the programmable completion facilities (see P\bPr\bro\bo-\b-
enabled by default.
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
- removal after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG
+ mand substitution, arithmetic expansion, and quote
+ removal 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
+ The shell sets this option if it is started in
restricted 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-
+ 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 s\bso\bou\bur\brc\bce\be (.\b.) 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.
x\bxp\bpg\bg_\b_e\bec\bch\bho\bo
- If set, the e\bec\bch\bho\bo builtin expands backslash-escape
+ If set, the e\bec\bch\bho\bo builtin expands backslash-escape
sequences by default.
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. The -\b-f\bf option says not to complain if this is a login
- shell; just suspend anyway. The return status is 0 unless the
+ Suspend the execution of this shell until it receives a S\bSI\bIG\bGC\bCO\bON\bNT\bT
+ signal. The -\b-f\bf option says not to complain if this is a login
+ shell; just suspend anyway. The return status is 0 unless the
shell is a login shell and -\b-f\bf is not supplied, or if job control
is not enabled.
t\bte\bes\bst\bt _\be_\bx_\bp_\br
[\b[ _\be_\bx_\bp_\br ]\b]
- Return a status of 0 or 1 depending on the evaluation 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
+ Return a status of 0 or 1 depending on the evaluation 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.
+ Expressions may be combined using the following operators,
+ listed in decreasing order of precedence. The evaluation
+ depends on the number of arguments; see below.
!\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
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. 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. Otherwise, the expression is false.
- The -\b-a\ba and -\b-o\bo operators are considered binary operators
- in this case.
+ 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-
+ wise, the expression is false.
4 arguments
If the first argument is !\b!, the result is the negation of
the three-argument expression composed of the remaining
-GNU Bash-3.2 2007 January 12 BASH(1)
+GNU Bash-3.2 2007 May 1 BASH(1)
--- /dev/null
+From: chet.ramey@case.edu (Chet Ramey)
+To: chet.ramey@gmail.com
+Subject: BASH Frequently-Asked Questions (FAQ version 3.36)
+Reply-To: chet@po.cwru.edu
+Archive-name: unix-faq/shell/bash
+Posting-Frequency: monthly
+Submitted-By: chet@po.cwru.edu (Chet Ramey)
+Last-Modified: Fri May 11 16:18:55 EDT 2007
+FAQ-Version: 3.36
+Bash-Version: 3.2
+URL: ftp://ftp.cwru.edu/pub/bash/FAQ
+Maintainer: chet@po.cwru.edu (Chet Ramey)
+
+This is the Bash FAQ, version 3.36, for Bash version 3.2.
+
+This document contains a set of frequently-asked questions concerning
+Bash, the GNU Bourne-Again Shell. Bash is a freely-available command
+interpreter with advanced features for both interactive use and shell
+programming.
+
+Another good source of basic information about shells is the collection
+of FAQ articles periodically posted to comp.unix.shell.
+
+Questions and comments concerning this document should be sent to
+chet.ramey@case.edu.
+
+This document is available for anonymous FTP with the URL
+
+ftp://ftp.cwru.edu/pub/bash/FAQ
+
+The Bash home page is http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html
+
+----------
+Contents:
+
+Section A: The Basics
+
+A1) What is it?
+A2) What's the latest version?
+A3) Where can I get it?
+A4) On what machines will bash run?
+A5) Will bash run on operating systems other than Unix?
+A6) How can I build bash with gcc?
+A7) How can I make bash my login shell?
+A8) I just changed my login shell to bash, and now I can't FTP into my
+ machine. Why not?
+A9) What's the `POSIX Shell and Utilities standard'?
+A10) What is the bash `posix mode'?
+
+Section B: The latest version
+
+B1) What's new in version 3.2?
+B2) Are there any user-visible incompatibilities between bash-3.2 and
+ bash-2.05b?
+
+Section C: Differences from other Unix shells
+
+C1) How does bash differ from sh, the Bourne shell?
+C2) How does bash differ from the Korn shell, version ksh88?
+C3) Which new features in ksh-93 are not in bash, and which are?
+
+Section D: Why does bash do some things differently than other Unix shells?
+
+D1) Why does bash run a different version of `command' than
+ `which command' says it will?
+D2) Why doesn't bash treat brace expansions exactly like csh?
+D3) Why doesn't bash have csh variable modifiers?
+D4) How can I make my csh aliases work when I convert to bash?
+D5) How can I pipe standard output and standard error from one command to
+ another, like csh does with `|&'?
+D6) Now that I've converted from ksh to bash, are there equivalents to
+ ksh features like autoloaded functions and the `whence' command?
+
+Section E: Why does bash do certain things the way it does?
+
+E1) Why is the bash builtin `test' slightly different from /bin/test?
+E2) Why does bash sometimes say `Broken pipe'?
+E3) When I have terminal escape sequences in my prompt, why does bash
+ wrap lines at the wrong column?
+E4) If I pipe the output of a command into `read variable', why doesn't
+ the output show up in $variable when the read command finishes?
+E5) I have a bunch of shell scripts that use backslash-escaped characters
+ in arguments to `echo'. Bash doesn't interpret these characters. Why
+ not, and how can I make it understand them?
+E6) Why doesn't a while or for loop get suspended when I type ^Z?
+E7) What about empty for loops in Makefiles?
+E8) Why does the arithmetic evaluation code complain about `08'?
+E9) Why does the pattern matching expression [A-Z]* match files beginning
+ with every letter except `z'?
+E10) Why does `cd //' leave $PWD as `//'?
+E11) If I resize my xterm while another program is running, why doesn't bash
+ notice the change?
+E12) Why don't negative offsets in substring expansion work like I expect?
+E13) Why does filename completion misbehave if a colon appears in the filename?
+E14) Why does quoting the pattern argument to the regular expression matching
+ conditional operator (=~) cause matching to stop working?
+
+Section F: Things to watch out for on certain Unix versions
+
+F1) Why can't I use command line editing in my `cmdtool'?
+F2) I built bash on Solaris 2. Why do globbing expansions and filename
+ completion chop off the first few characters of each filename?
+F3) Why does bash dump core after I interrupt username completion or
+ `~user' tilde expansion on a machine running NIS?
+F4) I'm running SVR4.2. Why is the line erased every time I type `@'?
+F5) Why does bash report syntax errors when my C News scripts use a
+ redirection before a subshell command?
+F6) Why can't I use vi-mode editing on Red Hat Linux 6.1?
+F7) Why do bash-2.05a and bash-2.05b fail to compile `printf.def' on
+ HP/UX 11.x?
+
+Section G: How can I get bash to do certain common things?
+
+G1) How can I get bash to read and display eight-bit characters?
+G2) How do I write a function `x' to replace builtin command `x', but
+ still invoke the command from within the function?
+G3) How can I find the value of a shell variable whose name is the value
+ of another shell variable?
+G4) How can I make the bash `time' reserved word print timing output that
+ looks like the output from my system's /usr/bin/time?
+G5) How do I get the current directory into my prompt?
+G6) How can I rename "*.foo" to "*.bar"?
+G7) How can I translate a filename from uppercase to lowercase?
+G8) How can I write a filename expansion (globbing) pattern that will match
+ all files in the current directory except "." and ".."?
+
+Section H: Where do I go from here?
+
+H1) How do I report bugs in bash, and where should I look for fixes and
+ advice?
+H2) What kind of bash documentation is there?
+H3) What's coming in future versions?
+H4) What's on the bash `wish list'?
+H5) When will the next release appear?
+
+----------
+Section A: The Basics
+
+A1) What is it?
+
+Bash is a Unix command interpreter (shell). It is an implementation of
+the Posix 1003.2 shell standard, and resembles the Korn and System V
+shells.
+
+Bash contains a number of enhancements over those shells, both
+for interactive use and shell programming. Features geared
+toward interactive use include command line editing, command
+history, job control, aliases, and prompt expansion. Programming
+features include additional variable expansions, shell
+arithmetic, and a number of variables and options to control
+shell behavior.
+
+Bash was originally written by Brian Fox of the Free Software
+Foundation. The current developer and maintainer is Chet Ramey
+of Case Western Reserve University.
+
+A2) What's the latest version?
+
+The latest version is 3.2, first made available on 12 October, 2006.
+
+A3) Where can I get it?
+
+Bash is the GNU project's shell, and so is available from the
+master GNU archive site, ftp.gnu.org, and its mirrors. The
+latest version is also available for FTP from ftp.cwru.edu.
+The following URLs tell how to get version 3.2:
+
+ftp://ftp.gnu.org/pub/gnu/bash/bash-3.2.tar.gz
+ftp://ftp.cwru.edu/pub/bash/bash-3.2.tar.gz
+
+Formatted versions of the documentation are available with the URLs:
+
+ftp://ftp.gnu.org/pub/gnu/bash/bash-doc-3.2.tar.gz
+ftp://ftp.cwru.edu/pub/bash/bash-doc-3.2.tar.gz
+
+Any patches for the current version are available with the URL:
+
+ftp://ftp.cwru.edu/pub/bash/bash-3.2-patches/
+
+A4) On what machines will bash run?
+
+Bash has been ported to nearly every version of Unix. All you
+should have to do to build it on a machine for which a port
+exists is to type `configure' and then `make'. The build process
+will attempt to discover the version of Unix you have and tailor
+itself accordingly, using a script created by GNU autoconf.
+
+More information appears in the file `INSTALL' in the distribution.
+
+The Bash web page (http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html)
+explains how to obtain binary versions of bash for most of the major
+commercial Unix systems.
+
+A5) Will bash run on operating systems other than Unix?
+
+Configuration specifics for Unix-like systems such as QNX and
+LynxOS are included in the distribution. Bash-2.05 and later
+versions should compile and run on Minix 2.0 (patches were
+contributed), but I don't believe anyone has built bash-2.x on
+earlier Minix versions yet.
+
+Bash has been ported to versions of Windows implementing the Win32
+programming interface. This includes Windows 95 and Windows NT.
+The port was done by Cygnus Solutions (now part of Red Hat) as part
+of their CYGWIN project. For more information about the project, see
+http://www.cygwin.com/.
+
+Cygnus originally ported bash-1.14.7, and that port was part of their
+early GNU-Win32 (the original name) releases. Cygnus has also done
+ports of bash-2.05b and bash-3.0 to the CYGWIN environment, and both
+are available as part of their current release. Bash-3.2 is currently
+being tested and should be available soon.
+
+Bash-2.05b and later versions should require no local Cygnus changes to
+build and run under CYGWIN.
+
+DJ Delorie has a port of bash-2.x which runs under MS-DOS, as part
+of the DJGPP project. For more information on the project, see
+
+http://www.delorie.com/djgpp/
+
+I have been told that the original DJGPP port was done by Daisuke Aoyama.
+
+Mark Elbrecht <snowball3@bigfoot.com> has sent me notice that bash-2.04
+is available for DJGPP V2. The files are available as:
+
+ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2gnu/bsh204b.zip binary
+ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2gnu/bsh204d.zip documentation
+ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2gnu/bsh204s.zip source
+
+Mark began to work with bash-2.05, but I don't know the current status.
+
+Bash-3.0 compiles and runs with no modifications under Microsoft's Services
+for Unix (SFU), once known as Interix. I do not anticipate any problems
+with building bash-3.1 or bash-3.2.
+
+A6) How can I build bash with gcc?
+
+Bash configures to use gcc by default if it is available. Read the
+file INSTALL in the distribution for more information.
+
+A7) How can I make bash my login shell?
+
+Some machines let you use `chsh' to change your login shell. Other
+systems use `passwd -s' or `passwd -e'. If one of these works for
+you, that's all you need. Note that many systems require the full
+pathname to a shell to appear in /etc/shells before you can make it
+your login shell. For this, you may need the assistance of your
+friendly local system administrator.
+
+If you cannot do this, you can still use bash as your login shell, but
+you need to perform some tricks. The basic idea is to add a command
+to your login shell's startup file to replace your login shell with
+bash.
+
+For example, if your login shell is csh or tcsh, and you have installed
+bash in /usr/gnu/bin/bash, add the following line to ~/.login:
+
+ if ( -f /usr/gnu/bin/bash ) exec /usr/gnu/bin/bash --login
+
+(the `--login' tells bash that it is a login shell).
+
+It's not a good idea to put this command into ~/.cshrc, because every
+csh you run without the `-f' option, even ones started to run csh scripts,
+reads that file. If you must put the command in ~/.cshrc, use something
+like
+
+ if ( $?prompt ) exec /usr/gnu/bin/bash --login
+
+to ensure that bash is exec'd only when the csh is interactive.
+
+If your login shell is sh or ksh, you have to do two things.
+
+First, create an empty file in your home directory named `.bash_profile'.
+The existence of this file will prevent the exec'd bash from trying to
+read ~/.profile, and re-execing itself over and over again. ~/.bash_profile
+is the first file bash tries to read initialization commands from when
+it is invoked as a login shell.
+
+Next, add a line similar to the above to ~/.profile:
+
+ [ -f /usr/gnu/bin/bash ] && [ -x /usr/gnu/bin/bash ] && \
+ exec /usr/gnu/bin/bash --login
+
+This will cause login shells to replace themselves with bash running as
+a login shell. Once you have this working, you can copy your initialization
+code from ~/.profile to ~/.bash_profile.
+
+I have received word that the recipe supplied above is insufficient for
+machines running CDE. CDE has a maze of twisty little startup files, all
+slightly different.
+
+If you cannot change your login shell in the password file to bash, you
+will have to (apparently) live with CDE using the shell in the password
+file to run its startup scripts. If you have changed your shell to bash,
+there is code in the CDE startup files (on Solaris, at least) that attempts
+to do the right thing. It is, however, often broken, and may require that
+you use the $BASH_ENV trick described below.
+
+`dtterm' claims to use $SHELL as the default program to start, so if you
+can change $SHELL in the CDE startup files, you should be able to use bash
+in your terminal windows.
+
+Setting DTSOURCEPROFILE in ~/.dtprofile will cause the `Xsession' program
+to read your login shell's startup files. You may be able to use bash for
+the rest of the CDE programs by setting SHELL to bash in ~/.dtprofile as
+well, but I have not tried this.
+
+You can use the above `exec' recipe to start bash when not logging in with
+CDE by testing the value of the DT variable:
+
+ if [ -n "$DT" ]; then
+ [ -f /usr/gnu/bin/bash ] && exec /usr/gnu/bin/bash --login
+ fi
+
+If CDE starts its shells non-interactively during login, the login shell
+startup files (~/.profile, ~/.bash_profile) will not be sourced at login.
+To get around this problem, append a line similar to the following to your
+~/.dtprofile:
+
+ BASH_ENV=${HOME}/.bash_profile ; export BASH_ENV
+
+and add the following line to the beginning of ~/.bash_profile:
+
+ unset BASH_ENV
+
+A8) I just changed my login shell to bash, and now I can't FTP into my
+ machine. Why not?
+
+You must add the full pathname to bash to the file /etc/shells. As
+noted in the answer to the previous question, many systems require
+this before you can make bash your login shell.
+
+Most versions of ftpd use this file to prohibit `special' users
+such as `uucp' and `news' from using FTP.
+
+A9) What's the `POSIX Shell and Utilities standard'?
+
+POSIX is a name originally coined by Richard Stallman for a
+family of open system standards based on UNIX. There are a
+number of aspects of UNIX under consideration for
+standardization, from the basic system services at the system
+call and C library level to applications and tools to system
+administration and management. Each area of standardization is
+assigned to a working group in the 1003 series.
+
+The POSIX Shell and Utilities standard was originally developed by
+IEEE Working Group 1003.2 (POSIX.2). Today it has been merged with
+the original 1003.1 Working Group and is maintained by the Austin
+Group (a joint working group of the 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 1003.1-2001, and
+thus now the former POSIX.2 (from 1992) is now part of the current
+POSIX.1 standard (POSIX 1003.1-2001).
+
+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 http://www.UNIX-systems.org/version3/ .
+Work continues at the Austin Group on maintenance issues; see
+http://www.opengroup.org/austin/ to join the discussions.
+
+Bash is concerned with the aspects of the shell's behavior defined
+by the POSIX 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
+pipelining, argument handling, variable expansion, and quoting.
+
+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 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 interactive
+behavior as part of the UPE, 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.
+
+The latest version of the POSIX Shell and Utilities standard is
+available (now updated to the 2004 Edition) as part of the Single
+UNIX Specification Version 3 at
+
+http://www.UNIX-systems.org/version3/
+
+A10) What is the bash `posix mode'?
+
+Although bash is an implementation of the POSIX shell
+specification, there are areas where the bash default behavior
+differs from that spec. The bash `posix mode' changes the bash
+behavior in these areas so that it obeys the spec more closely.
+
+Posix mode is entered by starting bash with the --posix or
+'-o posix' option or executing `set -o posix' after bash is running.
+
+The specific aspects of bash which change when posix mode is
+active are listed in the file POSIX in the bash distribution.
+They are also listed in a section in the Bash Reference Manual
+(from which that file is generated).
+
+Section B: The latest version
+
+B1) What's new in version 3.2?
+
+Bash-3.2 is the second maintenance release of the third major release of
+bash. It contains the following significant new features (see the manual
+page for complete descriptions and the CHANGES and NEWS files in the
+bash-3.2 distribution).
+
+o Bash-3.2 now checks shell scripts for NUL characters rather than non-printing
+ characters when deciding whether or not a script is a binary file.
+
+o Quoting the string argument to the [[ command's =~ (regexp) operator now
+ forces string matching, as with the other pattern-matching operators.
+
+A short feature history dating from Bash-2.0:
+
+Bash-3.1 contained the following new features:
+
+o Bash-3.1 may now be configured and built in a mode that enforces strict
+ POSIX compliance.
+
+o The `+=' assignment operator, which appends to the value of a string or
+ array variable, has been implemented.
+
+o It is now possible to ignore case when matching in contexts other than
+ filename generation using the new `nocasematch' shell option.
+
+Bash-3.0 contained the following new features:
+
+o Features to support the bash debugger have been implemented, and there
+ is a new `extdebug' option to turn the non-default options on
+
+o HISTCONTROL is now a colon-separated list of options and has been
+ extended with a new `erasedups' option that will result in only one
+ copy of a command being kept in the history list
+
+o Brace expansion has been extended with a new {x..y} form, producing
+ sequences of digits or characters
+
+o Timestamps are now kept with history entries, with an option to save
+ and restore them from the history file; there is a new HISTTIMEFORMAT
+ variable describing how to display the timestamps when listing history
+ entries
+
+o The `[[' command can now perform extended regular expression (egrep-like)
+ matching, with matched subexpressions placed in the BASH_REMATCH array
+ variable
+
+o A new `pipefail' option causes a pipeline to return a failure status if
+ any command in it fails
+
+o The `jobs', `kill', and `wait' builtins now accept job control notation
+ in their arguments even if job control is not enabled
+
+o The `gettext' package and libintl have been integrated, and the shell
+ messages may be translated into other languages
+
+Bash-2.05b introduced the following new features:
+
+o support for multibyte characters has been added to both bash and readline
+
+o the DEBUG trap is now run *before* simple commands, ((...)) commands,
+ [[...]] conditional commands, and for ((...)) loops
+
+o the shell now performs arithmetic in the largest integer size the machine
+ supports (intmax_t)
+
+o there is a new \D{...} prompt expansion; passes the `...' to strftime(3)
+ and inserts the result into the expanded prompt
+
+o there is a new `here-string' redirection operator: <<< word
+
+o when displaying variables, function attributes and definitions are shown
+ separately, allowing them to be re-used as input (attempting to re-use
+ the old output would result in syntax errors).
+
+o `read' has a new `-u fd' option to read from a specified file descriptor
+
+o the bash debugger in examples/bashdb has been modified to work with the
+ new DEBUG trap semantics, the command set has been made more gdb-like,
+ and the changes to $LINENO make debugging functions work better
+
+o the expansion of $LINENO inside a shell function is only relative to the
+ function start if the shell is interactive -- if the shell is running a
+ script, $LINENO expands to the line number in the script. This is as
+ POSIX-2001 requires
+
+Bash-2.05a introduced the following new features:
+
+o The `printf' builtin has undergone major work
+
+o There is a new read-only `shopt' option: login_shell, which is set by
+ login shells and unset otherwise
+
+o New `\A' prompt string escape sequence; expanding to time in 24-hour
+ HH:MM format
+
+o New `-A group/-g' option to complete and compgen; goes group name
+ completion
+
+o New [+-]O invocation option to set and unset `shopt' options at startup
+
+o ksh-like `ERR' trap
+
+o `for' loops now allow empty word lists after the `in' reserved word
+
+o new `hard' and `soft' arguments for the `ulimit' builtin
+
+o Readline can be configured to place the user at the same point on the line
+ when retrieving commands from the history list
+
+o Readline can be configured to skip `hidden' files (filenames with a leading
+ `.' on Unix) when performing completion
+
+Bash-2.05 introduced the following new features:
+
+o This version has once again reverted to using locales and strcoll(3) when
+ processing pattern matching bracket expressions, as POSIX requires.
+o Added a new `--init-file' invocation argument as a synonym for `--rcfile',
+ per the new GNU coding standards.
+o The /dev/tcp and /dev/udp redirections now accept service names as well as
+ port numbers.
+o `complete' and `compgen' now take a `-o value' option, which controls some
+ of the aspects of that compspec. Valid values are:
+
+ default - perform bash default completion if programmable
+ completion produces no matches
+ dirnames - perform directory name completion if programmable
+ completion produces no matches
+ filenames - tell readline that the compspec produces filenames,
+ so it can do things like append slashes to
+ directory names and suppress trailing spaces
+o A new loadable builtin, realpath, which canonicalizes and expands symlinks
+ in pathname arguments.
+o When `set' is called without options, it prints function defintions in a
+ way that allows them to be reused as input. This affects `declare' and
+ `declare -p' as well. This only happens when the shell is not in POSIX
+ mode, since POSIX.2 forbids this behavior.
+
+Bash-2.04 introduced the following new features:
+
+o Programmable word completion with the new `complete' and `compgen' builtins;
+ examples are provided in examples/complete/complete-examples
+o `history' has a new `-d' option to delete a history entry
+o `bind' has a new `-x' option to bind key sequences to shell commands
+o The prompt expansion code has new `\j' and `\l' escape sequences
+o The `no_empty_cmd_completion' shell option, if enabled, inhibits
+ command completion when TAB is typed on an empty line
+o `help' has a new `-s' option to print a usage synopsis
+o New arithmetic operators: var++, var--, ++var, --var, expr1,expr2 (comma)
+o New ksh93-style arithmetic for command:
+ for ((expr1 ; expr2; expr3 )); do list; done
+o `read' has new options: `-t', `-n', `-d', `-s'
+o The redirection code handles several filenames specially: /dev/fd/N,
+ /dev/stdin, /dev/stdout, /dev/stderr
+o The redirection code now recognizes /dev/tcp/HOST/PORT and
+ /dev/udp/HOST/PORT and tries to open a TCP or UDP socket, respectively,
+ to the specified port on the specified host
+o The ${!prefix*} expansion has been implemented
+o A new FUNCNAME variable, which expands to the name of a currently-executing
+ function
+o The GROUPS variable is no longer readonly
+o A new shopt `xpg_echo' variable, to control the behavior of echo with
+ respect to backslash-escape sequences at runtime
+o The NON_INTERACTIVE_LOGIN_SHELLS #define has returned
+
+The version of Readline released with Bash-2.04, Readline-4.1, had several
+new features as well:
+
+o Parentheses matching is always compiled into readline, and controllable
+ with the new `blink-matching-paren' variable
+o The history-search-forward and history-search-backward functions now leave
+ point at the end of the line when the search string is empty, like
+ reverse-search-history, and forward-search-history
+o A new function for applications: rl_on_new_line_with_prompt()
+o New variables for applications: rl_already_prompted, and rl_gnu_readline_p
+
+
+Bash-2.03 had very few new features, in keeping with the convention
+that odd-numbered releases provide mainly bug fixes. A number of new
+features were added to Readline, mostly at the request of the Cygnus
+folks.
+
+A new shopt option, `restricted_shell', so that startup files can test
+ whether or not the shell was started in restricted mode
+Filename generation is now performed on the words between ( and ) in
+ compound array assignments (this is really a bug fix)
+OLDPWD is now auto-exported, as POSIX.2 requires
+ENV and BASH_ENV are read-only variables in a restricted shell
+Bash may now be linked against an already-installed Readline library,
+ as long as the Readline library is version 4 or newer
+All shells begun with the `--login' option will source the login shell
+ startup files, even if the shell is not interactive
+
+There were lots of changes to the version of the Readline library released
+along with Bash-2.03. For a complete list of the changes, read the file
+CHANGES in the Bash-2.03 distribution.
+
+Bash-2.02 contained the following new features:
+
+a new version of malloc (based on the old GNU malloc code in previous
+ bash versions) that is more page-oriented, more conservative
+ with memory usage, does not `orphan' large blocks when they
+ are freed, is usable on 64-bit machines, and has allocation
+ checking turned on unconditionally
+POSIX.2-style globbing character classes ([:alpha:], [:alnum:], etc.)
+POSIX.2-style globbing equivalence classes
+POSIX.2-style globbing collating symbols
+the ksh [[...]] extended conditional command
+the ksh egrep-style extended pattern matching operators
+a new `printf' builtin
+the ksh-like $(<filename) command substitution, which is equivalent to
+ $(cat filename)
+new tilde prefixes that expand to directories from the directory stack
+new `**' arithmetic operator to do exponentiation
+case-insensitive globbing (filename expansion)
+menu completion a la tcsh
+`magic-space' history expansion function like tcsh
+the readline inputrc `language' has a new file inclusion directive ($include)
+
+Bash-2.01 contained only a few new features:
+
+new `GROUPS' builtin array variable containing the user's group list
+new bindable readline commands: history-and-alias-expand-line and
+ alias-expand-line
+
+Bash-2.0 contained extensive changes and new features from bash-1.14.7.
+Here's a short list:
+
+new `time' reserved word to time pipelines, shell builtins, and
+ shell functions
+one-dimensional arrays with a new compound assignment statement,
+ appropriate expansion constructs and modifications to some
+ of the builtins (read, declare, etc.) to use them
+new quoting syntaxes for ANSI-C string expansion and locale-specific
+ string translation
+new expansions to do substring extraction, pattern replacement, and
+ indirect variable expansion
+new builtins: `disown' and `shopt'
+new variables: HISTIGNORE, SHELLOPTS, PIPESTATUS, DIRSTACK, GLOBIGNORE,
+ MACHTYPE, BASH_VERSINFO
+special handling of many unused or redundant variables removed
+ (e.g., $notify, $glob_dot_filenames, $no_exit_on_failed_exec)
+dynamic loading of new builtin commands; many loadable examples provided
+new prompt expansions: \a, \e, \n, \H, \T, \@, \v, \V
+history and aliases available in shell scripts
+new readline variables: enable-keypad, mark-directories, input-meta,
+ visible-stats, disable-completion, comment-begin
+new readline commands to manipulate the mark and operate on the region
+new readline emacs mode commands and bindings for ksh-88 compatibility
+updated and extended builtins
+new DEBUG trap
+expanded (and now documented) restricted shell mode
+
+implementation stuff:
+autoconf-based configuration
+nearly all of the bugs reported since version 1.14 have been fixed
+most builtins converted to use builtin `getopt' for consistency
+most builtins use -p option to display output in a reusable form
+ (for consistency)
+grammar tighter and smaller (66 reduce-reduce conflicts gone)
+lots of code now smaller and faster
+test suite greatly expanded
+
+B2) Are there any user-visible incompatibilities between bash-3.2 and
+ bash-2.05b?
+
+There are a few incompatibilities between version 2.05b and version 3.2.
+They are detailed in the file COMPAT in the bash distribution. That file
+is not meant to be all-encompassing; send mail to bash-maintainers@gnu.org
+if if you find something that's not mentioned there.
+
+Section C: Differences from other Unix shells
+
+C1) How does bash differ from sh, the Bourne shell?
+
+This is a non-comprehensive list of features that differentiate bash
+from the SVR4.2 shell. The bash manual page explains these more
+completely.
+
+Things bash has that sh does not:
+ long invocation options
+ [+-]O invocation option
+ -l invocation option
+ `!' reserved word to invert pipeline return value
+ `time' reserved word to time pipelines and shell builtins
+ the `function' reserved word
+ the `select' compound command and reserved word
+ arithmetic for command: for ((expr1 ; expr2; expr3 )); do list; done
+ new $'...' and $"..." quoting
+ the $(...) form of command substitution
+ the $(<filename) form of command substitution, equivalent to
+ $(cat filename)
+ the ${#param} parameter value length operator
+ the ${!param} indirect parameter expansion operator
+ the ${!param*} prefix expansion operator
+ the ${param:offset[:length]} parameter substring operator
+ the ${param/pat[/string]} parameter pattern substitution operator
+ expansions to perform substring removal (${p%[%]w}, ${p#[#]w})
+ expansion of positional parameters beyond $9 with ${num}
+ variables: BASH, BASH_VERSION, BASH_VERSINFO, UID, EUID, REPLY,
+ TIMEFORMAT, PPID, PWD, OLDPWD, SHLVL, RANDOM, SECONDS,
+ LINENO, HISTCMD, HOSTTYPE, OSTYPE, MACHTYPE, HOSTNAME,
+ ENV, PS3, PS4, DIRSTACK, PIPESTATUS, HISTSIZE, HISTFILE,
+ HISTFILESIZE, HISTCONTROL, HISTIGNORE, GLOBIGNORE, GROUPS,
+ PROMPT_COMMAND, FCEDIT, FIGNORE, IGNOREEOF, INPUTRC,
+ SHELLOPTS, OPTERR, HOSTFILE, TMOUT, FUNCNAME, histchars,
+ auto_resume
+ DEBUG trap
+ ERR trap
+ variable arrays with new compound assignment syntax
+ redirections: <>, &>, >|, <<<, [n]<&word-, [n]>&word-
+ prompt string special char translation and variable expansion
+ auto-export of variables in initial environment
+ command search finds functions before builtins
+ bash return builtin will exit a file sourced with `.'
+ builtins: cd -/-L/-P, exec -l/-c/-a, echo -e/-E, hash -d/-l/-p/-t.
+ export -n/-f/-p/name=value, pwd -L/-P,
+ read -e/-p/-a/-t/-n/-d/-s/-u,
+ readonly -a/-f/name=value, trap -l, set +o,
+ set -b/-m/-o option/-h/-p/-B/-C/-H/-P,
+ unset -f/-v, ulimit -i/-m/-p/-q/-u/-x,
+ type -a/-p/-t/-f/-P, suspend -f, kill -n,
+ test -o optname/s1 == s2/s1 < s2/s1 > s2/-nt/-ot/-ef/-O/-G/-S
+ bash reads ~/.bashrc for interactive shells, $ENV for non-interactive
+ bash restricted shell mode is more extensive
+ bash allows functions and variables with the same name
+ brace expansion
+ tilde expansion
+ arithmetic expansion with $((...)) and `let' builtin
+ the `[[...]]' extended conditional command
+ process substitution
+ aliases and alias/unalias builtins
+ local variables in functions and `local' builtin
+ readline and command-line editing with programmable completion
+ command history and history/fc builtins
+ csh-like history expansion
+ other new bash builtins: bind, command, compgen, complete, builtin,
+ declare/typeset, dirs, enable, fc, help,
+ history, logout, popd, pushd, disown, shopt,
+ printf
+ exported functions
+ filename generation when using output redirection (command >a*)
+ POSIX.2-style globbing character classes
+ POSIX.2-style globbing equivalence classes
+ POSIX.2-style globbing collating symbols
+ egrep-like extended pattern matching operators
+ case-insensitive pattern matching and globbing
+ variable assignments preceding commands affect only that command,
+ even for builtins and functions
+ posix mode and strict posix conformance
+ redirection to /dev/fd/N, /dev/stdin, /dev/stdout, /dev/stderr,
+ /dev/tcp/host/port, /dev/udp/host/port
+ debugger support, including `caller' builtin and new variables
+ RETURN trap
+ the `+=' assignment operator
+
+
+Things sh has that bash does not:
+ uses variable SHACCT to do shell accounting
+ includes `stop' builtin (bash can use alias stop='kill -s STOP')
+ `newgrp' builtin
+ turns on job control if called as `jsh'
+ $TIMEOUT (like bash $TMOUT)
+ `^' is a synonym for `|'
+ new SVR4.2 sh builtins: mldmode, priv
+
+Implementation differences:
+ redirection to/from compound commands causes sh to create a subshell
+ bash does not allow unbalanced quotes; sh silently inserts them at EOF
+ bash does not mess with signal 11
+ sh sets (euid, egid) to (uid, gid) if -p not supplied and uid < 100
+ bash splits only the results of expansions on IFS, using POSIX.2
+ field splitting rules; sh splits all words on IFS
+ sh does not allow MAILCHECK to be unset (?)
+ sh does not allow traps on SIGALRM or SIGCHLD
+ bash allows multiple option arguments when invoked (e.g. -x -v);
+ sh allows only a single option argument (`sh -x -v' attempts
+ to open a file named `-v', and, on SunOS 4.1.4, dumps core.
+ On Solaris 2.4 and earlier versions, sh goes into an infinite
+ loop.)
+ sh exits a script if any builtin fails; bash exits only if one of
+ the POSIX.2 `special' builtins fails
+
+C2) How does bash differ from the Korn shell, version ksh88?
+
+Things bash has or uses that ksh88 does not:
+ long invocation options
+ [-+]O invocation option
+ -l invocation option
+ `!' reserved word
+ arithmetic for command: for ((expr1 ; expr2; expr3 )); do list; done
+ arithmetic in largest machine-supported size (intmax_t)
+ posix mode and posix conformance
+ command hashing
+ tilde expansion for assignment statements that look like $PATH
+ process substitution with named pipes if /dev/fd is not available
+ the ${!param} indirect parameter expansion operator
+ the ${!param*} prefix expansion operator
+ the ${param:offset[:length]} parameter substring operator
+ the ${param/pat[/string]} parameter pattern substitution operator
+ variables: BASH, BASH_VERSION, BASH_VERSINFO, UID, EUID, SHLVL,
+ TIMEFORMAT, HISTCMD, HOSTTYPE, OSTYPE, MACHTYPE,
+ HISTFILESIZE, HISTIGNORE, HISTCONTROL, PROMPT_COMMAND,
+ IGNOREEOF, FIGNORE, INPUTRC, HOSTFILE, DIRSTACK,
+ PIPESTATUS, HOSTNAME, OPTERR, SHELLOPTS, GLOBIGNORE,
+ GROUPS, FUNCNAME, histchars, auto_resume
+ prompt expansion with backslash escapes and command substitution
+ redirection: &> (stdout and stderr), <<<, [n]<&word-, [n]>&word-
+ more extensive and extensible editing and programmable completion
+ builtins: bind, builtin, command, declare, dirs, echo -e/-E, enable,
+ exec -l/-c/-a, fc -s, export -n/-f/-p, hash, help, history,
+ jobs -x/-r/-s, kill -s/-n/-l, local, logout, popd, pushd,
+ read -e/-p/-a/-t/-n/-d/-s, readonly -a/-n/-f/-p,
+ set -o braceexpand/-o histexpand/-o interactive-comments/
+ -o notify/-o physical/-o posix/-o hashall/-o onecmd/
+ -h/-B/-C/-b/-H/-P, set +o, suspend, trap -l, type,
+ typeset -a/-F/-p, ulimit -i/-q/-u/-x, umask -S, alias -p,
+ shopt, disown, printf, complete, compgen
+ `!' csh-style history expansion
+ POSIX.2-style globbing character classes
+ POSIX.2-style globbing equivalence classes
+ POSIX.2-style globbing collating symbols
+ egrep-like extended pattern matching operators
+ case-insensitive pattern matching and globbing
+ `**' arithmetic operator to do exponentiation
+ redirection to /dev/fd/N, /dev/stdin, /dev/stdout, /dev/stderr
+ arrays of unlimited size
+ TMOUT is default timeout for `read' and `select'
+ debugger support, including the `caller' builtin
+ RETURN trap
+ Timestamps in history entries
+ {x..y} brace expansion
+ The `+=' assignment operator
+
+Things ksh88 has or uses that bash does not:
+ tracked aliases (alias -t)
+ variables: ERRNO, FPATH, EDITOR, VISUAL
+ co-processes (|&, >&p, <&p)
+ weirdly-scoped functions
+ typeset +f to list all function names without definitions
+ text of command history kept in a file, not memory
+ builtins: alias -x, cd old new, newgrp, print,
+ read -p/-s/var?prompt, set -A/-o gmacs/
+ -o bgnice/-o markdirs/-o trackall/-o viraw/-s,
+ typeset -H/-L/-R/-Z/-A/-ft/-fu/-fx/-l/-u/-t, whence
+ using environment to pass attributes of exported variables
+ arithmetic evaluation done on arguments to some builtins
+ reads .profile from $PWD when invoked as login shell
+
+Implementation differences:
+ ksh runs last command of a pipeline in parent shell context
+ bash has brace expansion by default (ksh88 compile-time option)
+ bash has fixed startup file for all interactive shells; ksh reads $ENV
+ bash has exported functions
+ bash command search finds functions before builtins
+ bash waits for all commands in pipeline to exit before returning status
+ emacs-mode editing has some slightly different key bindings
+
+C3) Which new features in ksh-93 are not in bash, and which are?
+
+New things in ksh-93 not in bash-3.2:
+ associative arrays
+ floating point arithmetic and variables
+ math library functions
+ ${!name[sub]} name of subscript for associative array
+ `.' is allowed in variable names to create a hierarchical namespace
+ more extensive compound assignment syntax
+ discipline functions
+ `sleep' and `getconf' builtins (bash has loadable versions)
+ typeset -n and `nameref' variables
+ KEYBD trap
+ variables: .sh.edchar, .sh.edmode, .sh.edcol, .sh.edtext, .sh.version,
+ .sh.name, .sh.subscript, .sh.value, .sh.match, HISTEDIT
+ backreferences in pattern matching (\N)
+ `&' operator in pattern lists for matching
+ print -f (bash uses printf)
+ `fc' has been renamed to `hist'
+ `.' can execute shell functions
+ exit statuses between 0 and 255
+ FPATH and PATH mixing
+ getopts -a
+ -I invocation option
+ printf %H, %P, %T, %Z modifiers, output base for %d
+ lexical scoping for local variables in `ksh' functions
+ no scoping for local variables in `POSIX' functions
+
+New things in ksh-93 present in bash-3.2:
+ [n]<&word- and [n]>&word- redirections (combination dup and close)
+ for (( expr1; expr2; expr3 )) ; do list; done - arithmetic for command
+ ?:, ++, --, `expr1 , expr2' arithmetic operators
+ expansions: ${!param}, ${param:offset[:len]}, ${param/pat[/str]},
+ ${!param*}
+ compound array assignment
+ the `!' reserved word
+ loadable builtins -- but ksh uses `builtin' while bash uses `enable'
+ `command', `builtin', `disown' builtins
+ new $'...' and $"..." quoting
+ FIGNORE (but bash uses GLOBIGNORE), HISTCMD
+ set -o notify/-C
+ changes to kill builtin
+ read -A (bash uses read -a)
+ read -t/-d
+ trap -p
+ exec -c/-a
+ `.' restores the positional parameters when it completes
+ POSIX.2 `test'
+ umask -S
+ unalias -a
+ command and arithmetic substitution performed on PS1, PS4, and ENV
+ command name completion
+ ENV processed only for interactive shells
+ set -o pipefail
+ The `+=' assignment operator
+
+Section D: Why does bash do some things differently than other Unix shells?
+
+D1) Why does bash run a different version of `command' than
+ `which command' says it will?
+
+On many systems, `which' is actually a csh script that assumes
+you're running csh. In tcsh, `which' and its cousin `where'
+are builtins. On other Unix systems, `which' is a perl script
+that uses the PATH environment variable. Many Linux distributions
+use GNU `which', which is a C program that can understand shell
+aliases.
+
+The csh script version reads the csh startup files from your
+home directory and uses those to determine which `command' will
+be invoked. Since bash doesn't use any of those startup files,
+there's a good chance that your bash environment differs from
+your csh environment. The bash `type' builtin does everything
+`which' does, and will report correct results for the running
+shell. If you're really wedded to the name `which', try adding
+the following function definition to your .bashrc:
+
+ which()
+ {
+ builtin type "$@"
+ }
+
+If you're moving from tcsh and would like to bring `where' along
+as well, use this function:
+
+ where()
+ {
+ builtin type -a "$@"
+ }
+
+D2) Why doesn't bash treat brace expansions exactly like csh?
+
+The only difference between bash and csh brace expansion is that
+bash requires a brace expression to contain at least one unquoted
+comma if it is to be expanded. Any brace-surrounded word not
+containing an unquoted comma is left unchanged by the brace
+expansion code. This affords the greatest degree of sh
+compatibility.
+
+Bash, ksh, zsh, and pd-ksh all implement brace expansion this way.
+
+D3) Why doesn't bash have csh variable modifiers?
+
+Posix has specified a more powerful, albeit somewhat more cryptic,
+mechanism cribbed from ksh, and bash implements it.
+
+${parameter%word}
+ Remove smallest suffix pattern. The WORD is expanded to produce
+ a pattern. It then expands to the value of PARAMETER, with the
+ smallest portion of the suffix matched by the pattern deleted.
+
+ x=file.c
+ echo ${x%.c}.o
+ -->file.o
+
+${parameter%%word}
+
+ Remove largest suffix pattern. The WORD is expanded to produce
+ a pattern. It then expands to the value of PARAMETER, with the
+ largest portion of the suffix matched by the pattern deleted.
+
+ x=posix/src/std
+ echo ${x%%/*}
+ -->posix
+
+${parameter#word}
+ Remove smallest prefix pattern. The WORD is expanded to produce
+ a pattern. It then expands to the value of PARAMETER, with the
+ smallest portion of the prefix matched by the pattern deleted.
+
+ x=$HOME/src/cmd
+ echo ${x#$HOME}
+ -->/src/cmd
+
+${parameter##word}
+ Remove largest prefix pattern. The WORD is expanded to produce
+ a pattern. It then expands to the value of PARAMETER, with the
+ largest portion of the prefix matched by the pattern deleted.
+
+ x=/one/two/three
+ echo ${x##*/}
+ -->three
+
+
+Given
+ a=/a/b/c/d
+ b=b.xxx
+
+ csh bash result
+ --- ---- ------
+ $a:h ${a%/*} /a/b/c
+ $a:t ${a##*/} d
+ $b:r ${b%.*} b
+ $b:e ${b##*.} xxx
+
+
+D4) How can I make my csh aliases work when I convert to bash?
+
+Bash uses a different syntax to support aliases than csh does.
+The details can be found in the documentation. We have provided
+a shell script which does most of the work of conversion for you;
+this script can be found in ./examples/misc/aliasconv.sh. Here is
+how you use it:
+
+Start csh in the normal way for you. (e.g., `csh')
+
+Pipe the output of `alias' through `aliasconv.sh', saving the
+results into `bash_aliases':
+
+ alias | bash aliasconv.sh >bash_aliases
+
+Edit `bash_aliases', carefully reading through any created
+functions. You will need to change the names of some csh specific
+variables to the bash equivalents. The script converts $cwd to
+$PWD, $term to $TERM, $home to $HOME, $user to $USER, and $prompt
+to $PS1. You may also have to add quotes to avoid unwanted
+expansion.
+
+For example, the csh alias:
+
+ alias cd 'cd \!*; echo $cwd'
+
+is converted to the bash function:
+
+ cd () { command cd "$@"; echo $PWD ; }
+
+The only thing that needs to be done is to quote $PWD:
+
+ cd () { command cd "$@"; echo "$PWD" ; }
+
+Merge the edited file into your ~/.bashrc.
+
+There is an additional, more ambitious, script in
+examples/misc/cshtobash that attempts to convert your entire csh
+environment to its bash equivalent. This script can be run as
+simply `cshtobash' to convert your normal interactive
+environment, or as `cshtobash ~/.login' to convert your login
+environment.
+
+D5) How can I pipe standard output and standard error from one command to
+ another, like csh does with `|&'?
+
+Use
+ command 2>&1 | command2
+
+The key is to remember that piping is performed before redirection, so
+file descriptor 1 points to the pipe when it is duplicated onto file
+descriptor 2.
+
+D6) Now that I've converted from ksh to bash, are there equivalents to
+ ksh features like autoloaded functions and the `whence' command?
+
+There are features in ksh-88 and ksh-93 that do not have direct bash
+equivalents. Most, however, can be emulated with very little trouble.
+
+ksh-88 feature Bash equivalent
+-------------- ---------------
+compiled-in aliases set up aliases in .bashrc; some ksh aliases are
+ bash builtins (hash, history, type)
+coprocesses named pipe pairs (one for read, one for write)
+typeset +f declare -F
+cd, print, whence function substitutes in examples/functions/kshenv
+autoloaded functions examples/functions/autoload is the same as typeset -fu
+read var?prompt read -p prompt var
+
+ksh-93 feature Bash equivalent
+-------------- ---------------
+sleep, getconf Bash has loadable versions in examples/loadables
+${.sh.version} $BASH_VERSION
+print -f printf
+hist alias hist=fc
+$HISTEDIT $FCEDIT
+
+Section E: How can I get bash to do certain things, and why does bash do
+ things the way it does?
+
+E1) Why is the bash builtin `test' slightly different from /bin/test?
+
+The specific example used here is [ ! x -o x ], which is false.
+
+Bash's builtin `test' implements the Posix.2 spec, which can be
+summarized as follows (the wording is due to David Korn):
+
+Here is the set of rules for processing test arguments.
+
+ 0 Args: False
+ 1 Arg: True iff argument is not null.
+ 2 Args: If first arg is !, True iff second argument is null.
+ If first argument is unary, then true if unary test is true
+ Otherwise error.
+ 3 Args: If second argument is a binary operator, do binary test of $1 $3
+ If first argument is !, negate two argument test of $2 $3
+ If first argument is `(' and third argument is `)', do the
+ one-argument test of the second argument.
+ Otherwise error.
+ 4 Args: If first argument is !, negate three argument test of $2 $3 $4.
+ Otherwise unspecified
+ 5 or more Args: unspecified. (Historical shells would use their
+ current algorithm).
+
+The operators -a and -o are considered binary operators for the purpose
+of the 3 Arg case.
+
+As you can see, the test becomes (not (x or x)), which is false.
+
+E2) Why does bash sometimes say `Broken pipe'?
+
+If a sequence of commands appears in a pipeline, and one of the
+reading commands finishes before the writer has finished, the
+writer receives a SIGPIPE signal. Many other shells special-case
+SIGPIPE as an exit status in the pipeline and do not report it.
+For example, in:
+
+ ps -aux | head
+
+`head' can finish before `ps' writes all of its output, and ps
+will try to write on a pipe without a reader. In that case, bash
+will print `Broken pipe' to stderr when ps is killed by a
+SIGPIPE.
+
+As of bash-3.1, bash does not report SIGPIPE errors by default. You
+can build a version of bash that will report such errors.
+
+E3) When I have terminal escape sequences in my prompt, why does bash
+ wrap lines at the wrong column?
+
+Readline, the line editing library that bash uses, does not know
+that the terminal escape sequences do not take up space on the
+screen. The redisplay code assumes, unless told otherwise, that
+each character in the prompt is a `printable' character that
+takes up one character position on the screen.
+
+You can use the bash prompt expansion facility (see the PROMPTING
+section in the manual page) to tell readline that sequences of
+characters in the prompt strings take up no screen space.
+
+Use the \[ escape to begin a sequence of non-printing characters,
+and the \] escape to signal the end of such a sequence.
+
+E4) If I pipe the output of a command into `read variable', why doesn't
+ the output show up in $variable when the read command finishes?
+
+This has to do with the parent-child relationship between Unix
+processes. It affects all commands run in pipelines, not just
+simple calls to `read'. For example, piping a command's output
+into a `while' loop that repeatedly calls `read' will result in
+the same behavior.
+
+Each element of a pipeline, even a builtin or shell function,
+runs in a separate process, a child of the shell running the
+pipeline. A subprocess cannot affect its parent's environment.
+When the `read' command sets the variable to the input, that
+variable is set only in the subshell, not the parent shell. When
+the subshell exits, the value of the variable is lost.
+
+Many pipelines that end with `read variable' can be converted
+into command substitutions, which will capture the output of
+a specified command. The output can then be assigned to a
+variable:
+
+ grep ^gnu /usr/lib/news/active | wc -l | read ngroup
+
+can be converted into
+
+ ngroup=$(grep ^gnu /usr/lib/news/active | wc -l)
+
+This does not, unfortunately, work to split the text among
+multiple variables, as read does when given multiple variable
+arguments. If you need to do this, you can either use the
+command substitution above to read the output into a variable
+and chop up the variable using the bash pattern removal
+expansion operators or use some variant of the following
+approach.
+
+Say /usr/local/bin/ipaddr is the following shell script:
+
+#! /bin/sh
+host `hostname` | awk '/address/ {print $NF}'
+
+Instead of using
+
+ /usr/local/bin/ipaddr | read A B C D
+
+to break the local machine's IP address into separate octets, use
+
+ OIFS="$IFS"
+ IFS=.
+ set -- $(/usr/local/bin/ipaddr)
+ IFS="$OIFS"
+ A="$1" B="$2" C="$3" D="$4"
+
+Beware, however, that this will change the shell's positional
+parameters. If you need them, you should save them before doing
+this.
+
+This is the general approach -- in most cases you will not need to
+set $IFS to a different value.
+
+Some other user-supplied alternatives include:
+
+read A B C D << HERE
+ $(IFS=.; echo $(/usr/local/bin/ipaddr))
+HERE
+
+and, where process substitution is available,
+
+read A B C D < <(IFS=.; echo $(/usr/local/bin/ipaddr))
+
+E5) I have a bunch of shell scripts that use backslash-escaped characters
+ in arguments to `echo'. Bash doesn't interpret these characters. Why
+ not, and how can I make it understand them?
+
+This is the behavior of echo on most Unix System V machines.
+
+The bash builtin `echo' is modeled after the 9th Edition
+Research Unix version of `echo'. It does not interpret
+backslash-escaped characters in its argument strings by default;
+it requires the use of the -e option to enable the
+interpretation. The System V echo provides no way to disable the
+special characters; the bash echo has a -E option to disable
+them.
+
+There is a configuration option that will make bash behave like
+the System V echo and interpret things like `\t' by default. Run
+configure with the --enable-xpg-echo-default option to turn this
+on. Be aware that this will cause some of the tests run when you
+type `make tests' to fail.
+
+There is a shell option, `xpg_echo', settable with `shopt', that will
+change the behavior of echo at runtime. Enabling this option turns
+on expansion of backslash-escape sequences.
+
+E6) Why doesn't a while or for loop get suspended when I type ^Z?
+
+This is a consequence of how job control works on Unix. The only
+thing that can be suspended is the process group. This is a single
+command or pipeline of commands that the shell forks and executes.
+
+When you run a while or for loop, the only thing that the shell forks
+and executes are any commands in the while loop test and commands in
+the loop bodies. These, therefore, are the only things that can be
+suspended when you type ^Z.
+
+If you want to be able to stop the entire loop, you need to put it
+within parentheses, which will force the loop into a subshell that
+may be stopped (and subsequently restarted) as a single unit.
+
+E7) What about empty for loops in Makefiles?
+
+It's fairly common to see constructs like this in automatically-generated
+Makefiles:
+
+SUBDIRS = @SUBDIRS@
+
+ ...
+
+subdirs-clean:
+ for d in ${SUBDIRS}; do \
+ ( cd $$d && ${MAKE} ${MFLAGS} clean ) \
+ done
+
+When SUBDIRS is empty, this results in a command like this being passed to
+bash:
+
+ for d in ; do
+ ( cd $d && ${MAKE} ${MFLAGS} clean )
+ done
+
+In versions of bash before bash-2.05a, this was a syntax error. If the
+reserved word `in' was present, a word must follow it before the semicolon
+or newline. The language in the manual page referring to the list of words
+being empty referred to the list after it is expanded. These versions of
+bash required that there be at least one word following the `in' when the
+construct was parsed.
+
+The idiomatic Makefile solution is something like:
+
+SUBDIRS = @SUBDIRS@
+
+subdirs-clean:
+ subdirs=$SUBDIRS ; for d in $$subdirs; do \
+ ( cd $$d && ${MAKE} ${MFLAGS} clean ) \
+ done
+
+The latest updated POSIX standard has changed this: the word list
+is no longer required. Bash versions 2.05a and later accept the
+new syntax.
+
+E8) Why does the arithmetic evaluation code complain about `08'?
+
+The bash arithmetic evaluation code (used for `let', $(()), (()), and in
+other places), interprets a leading `0' in numeric constants as denoting
+an octal number, and a leading `0x' as denoting hexadecimal. This is
+in accordance with the POSIX.2 spec, section 2.9.2.1, which states that
+arithmetic constants should be handled as signed long integers as defined
+by the ANSI/ISO C standard.
+
+The POSIX.2 interpretation committee has confirmed this:
+
+http://www.pasc.org/interps/unofficial/db/p1003.2/pasc-1003.2-173.html
+
+E9) Why does the pattern matching expression [A-Z]* match files beginning
+ with every letter except `z'?
+
+Bash-2.03, Bash-2.05 and later versions honor the current locale setting
+when processing ranges within pattern matching bracket expressions ([A-Z]).
+This is what POSIX.2 and SUSv3/XPG6 specify.
+
+The behavior of the matcher in bash-2.05 and later versions depends on the
+current LC_COLLATE setting. Setting this variable to `C' or `POSIX' will
+result in the traditional behavior ([A-Z] matches all uppercase ASCII
+characters). Many other locales, including the en_US locale (the default
+on many US versions of Linux) collate the upper and lower case letters like
+this:
+
+ AaBb...Zz
+
+which means that [A-Z] matches every letter except `z'. Others collate like
+
+ aAbBcC...zZ
+
+which means that [A-Z] matches every letter except `a'.
+
+The portable way to specify upper case letters is [:upper:] instead of
+A-Z; lower case may be specified as [:lower:] instead of a-z.
+
+Look at the manual pages for setlocale(3), strcoll(3), and, if it is
+present, locale(1). If you have locale(1), you can use it to find
+your current locale information even if you do not have any of the
+LC_ variables set.
+
+My advice is to put
+
+ export LC_COLLATE=C
+
+into /etc/profile and inspect any shell scripts run from cron for
+constructs like [A-Z]. This will prevent things like
+
+ rm [A-Z]*
+
+from removing every file in the current directory except those beginning
+with `z' and still allow individual users to change the collation order.
+Users may put the above command into their own profiles as well, of course.
+
+E10) Why does `cd //' leave $PWD as `//'?
+
+POSIX.2, in its description of `cd', says that *three* or more leading
+slashes may be replaced with a single slash when canonicalizing the
+current working directory.
+
+This is, I presume, for historical compatibility. Certain versions of
+Unix, and early network file systems, used paths of the form
+//hostname/path to access `path' on server `hostname'.
+
+E11) If I resize my xterm while another program is running, why doesn't bash
+ notice the change?
+
+This is another issue that deals with job control.
+
+The kernel maintains a notion of a current terminal process group. Members
+of this process group (processes whose process group ID is equal to the
+current terminal process group ID) receive terminal-generated signals like
+SIGWINCH. (For more details, see the JOB CONTROL section of the bash
+man page.)
+
+If a terminal is resized, the kernel sends SIGWINCH to each member of
+the terminal's current process group (the `foreground' process group).
+
+When bash is running with job control enabled, each pipeline (which may be
+a single command) is run in its own process group, different from bash's
+process group. This foreground process group receives the SIGWINCH; bash
+does not. Bash has no way of knowing that the terminal has been resized.
+
+There is a `checkwinsize' option, settable with the `shopt' builtin, that
+will cause bash to check the window size and adjust its idea of the
+terminal's dimensions each time a process stops or exits and returns control
+of the terminal to bash. Enable it with `shopt -s checkwinsize'.
+
+E12) Why don't negative offsets in substring expansion work like I expect?
+
+When substring expansion of the form ${param:offset[:length} is used,
+an `offset' that evaluates to a number less than zero counts back from
+the end of the expanded value of $param.
+
+When a negative `offset' begins with a minus sign, however, unexpected things
+can happen. Consider
+
+ a=12345678
+ echo ${a:-4}
+
+intending to print the last four characters of $a. The problem is that
+${param:-word} already has a well-defined meaning: expand to word if the
+expanded value of param is unset or null, and $param otherwise.
+
+To use negative offsets that begin with a minus sign, separate the
+minus sign and the colon with a space.
+
+E13) Why does filename completion misbehave if a colon appears in the filename?
+
+Filename completion (and word completion in general) may appear to behave
+improperly if there is a colon in the word to be completed.
+
+The colon is special to readline's word completion code: it is one of the
+characters that breaks words for the completer. Readline uses these characters
+in sort of the same way that bash uses $IFS: they break or separate the words
+the completion code hands to the application-specific or default word
+completion functions. The original intent was to make it easy to edit
+colon-separated lists (such as $PATH in bash) in various applications using
+readline for input.
+
+This is complicated by the fact that some versions of the popular
+`bash-completion' programmable completion package have problems with the
+default completion behavior in the presence of colons.
+
+The current set of completion word break characters is available in bash as
+the value of the COMP_WORDBREAKS variable. Removing `:' from that value is
+enough to make the colon not special to completion:
+
+COMP_WORDBREAKS=${COMP_WORDBREAKS//:}
+
+You can also quote the colon with a backslash to achieve the same result
+temporarily.
+
+E14) Why does quoting the pattern argument to the regular expression matching
+ conditional operator (=~) cause regexp matching to stop working?
+
+In versions of bash prior to bash-3.2, the effect of quoting the regular
+expression argument to the [[ command's =~ operator was not specified.
+The practical effect was that double-quoting the pattern argument required
+backslashes to quote special pattern characters, which interfered with the
+backslash processing performed by double-quoted word expansion and was
+inconsistent with how the == shell pattern matching operator treated
+quoted characters.
+
+In bash-3.2, the shell was changed to internally quote characters in single-
+and double-quoted string arguments to the =~ operator, which suppresses the
+special meaning of the characters special to regular expression processing
+(`.', `[', `\', `(', `), `*', `+', `?', `{', `|', `^', and `$') and forces
+them to be matched literally. This is consistent with how the `==' pattern
+matching operator treats quoted portions of its pattern argument.
+
+Since the treatment of quoted string arguments was changed, several issues
+have arisen, chief among them the problem of white space in pattern arguments
+and the differing treatment of quoted strings between bash-3.1 and bash-3.2.
+Both problems may be solved by using a shell variable to hold the pattern.
+Since word splitting is not performed when expanding shell variables in all
+operands of the [[ command, this allows users to quote patterns as they wish
+when assigning the variable, then expand the values to a single string that
+may contain whitespace. The first problem may be solved by using backslashes
+or any other quoting mechanism to escape the white space in the patterns.
+
+Section F: Things to watch out for on certain Unix versions
+
+F1) Why can't I use command line editing in my `cmdtool'?
+
+The problem is `cmdtool' and bash fighting over the input. When
+scrolling is enabled in a cmdtool window, cmdtool puts the tty in
+`raw mode' to permit command-line editing using the mouse for
+applications that cannot do it themselves. As a result, bash and
+cmdtool each try to read keyboard input immediately, with neither
+getting enough of it to be useful.
+
+This mode also causes cmdtool to not implement many of the
+terminal functions and control sequences appearing in the
+`sun-cmd' termcap entry. For a more complete explanation, see
+that file examples/suncmd.termcap in the bash distribution.
+
+`xterm' is a better choice, and gets along with bash much more
+smoothly.
+
+If you must use cmdtool, you can use the termcap description in
+examples/suncmd.termcap. Set the TERMCAP variable to the terminal
+description contained in that file, i.e.
+
+TERMCAP='Mu|sun-cmd:am:bs:km:pt:li#34:co#80:cl=^L:ce=\E[K:cd=\E[J:rs=\E[s:'
+
+Then export TERMCAP and start a new cmdtool window from that shell.
+The bash command-line editing should behave better in the new
+cmdtool. If this works, you can put the assignment to TERMCAP
+in your bashrc file.
+
+F2) I built bash on Solaris 2. Why do globbing expansions and filename
+ completion chop off the first few characters of each filename?
+
+This is the consequence of building bash on SunOS 5 and linking
+with the libraries in /usr/ucblib, but using the definitions
+and structures from files in /usr/include.
+
+The actual conflict is between the dirent structure in
+/usr/include/dirent.h and the struct returned by the version of
+`readdir' in libucb.a (a 4.3-BSD style `struct direct').
+
+Make sure you've got /usr/ccs/bin ahead of /usr/ucb in your $PATH
+when configuring and building bash. This will ensure that you
+use /usr/ccs/bin/cc or acc instead of /usr/ucb/cc and that you
+link with libc before libucb.
+
+If you have installed the Sun C compiler, you may also need to
+put /usr/ccs/bin and /opt/SUNWspro/bin into your $PATH before
+/usr/ucb.
+
+F3) Why does bash dump core after I interrupt username completion or
+ `~user' tilde expansion on a machine running NIS?
+
+This is a famous and long-standing bug in the SunOS YP (sorry, NIS)
+client library, which is part of libc.
+
+The YP library code keeps static state -- a pointer into the data
+returned from the server. When YP initializes itself (setpwent),
+it looks at this pointer and calls free on it if it's non-null.
+So far, so good.
+
+If one of the YP functions is interrupted during getpwent (the
+exact function is interpretwithsave()), and returns NULL, the
+pointer is freed without being reset to NULL, and the function
+returns. The next time getpwent is called, it sees that this
+pointer is non-null, calls free, and the bash free() blows up
+because it's being asked to free freed memory.
+
+The traditional Unix mallocs allow memory to be freed multiple
+times; that's probably why this has never been fixed. You can
+run configure with the `--without-gnu-malloc' option to use
+the C library malloc and avoid the problem.
+
+F4) I'm running SVR4.2. Why is the line erased every time I type `@'?
+
+The `@' character is the default `line kill' character in most
+versions of System V, including SVR4.2. You can change this
+character to whatever you want using `stty'. For example, to
+change the line kill character to control-u, type
+
+ stty kill ^U
+
+where the `^' and `U' can be two separate characters.
+
+F5) Why does bash report syntax errors when my C News scripts use a
+ redirection before a subshell command?
+
+The actual command in question is something like
+
+ < file ( command )
+
+According to the grammar given in the POSIX.2 standard, this construct
+is, in fact, a syntax error. Redirections may only precede `simple
+commands'. A subshell construct such as the above is one of the shell's
+`compound commands'. A redirection may only follow a compound command.
+
+This affects the mechanical transformation of commands that use `cat'
+to pipe a file into a command (a favorite Useless-Use-Of-Cat topic on
+comp.unix.shell). While most commands of the form
+
+ cat file | command
+
+can be converted to `< file command', shell control structures such as
+loops and subshells require `command < file'.
+
+The file CWRU/sh-redir-hack in the bash distribution is an
+(unofficial) patch to parse.y that will modify the grammar to
+support this construct. It will not apply with `patch'; you must
+modify parse.y by hand. Note that if you apply this, you must
+recompile with -DREDIRECTION_HACK. This introduces a large
+number of reduce/reduce conflicts into the shell grammar.
+
+F6) Why can't I use vi-mode editing on Red Hat Linux 6.1?
+
+The short answer is that Red Hat screwed up.
+
+The long answer is that they shipped an /etc/inputrc that only works
+for emacs mode editing, and then screwed all the vi users by setting
+INPUTRC to /etc/inputrc in /etc/profile.
+
+The short fix is to do one of the following: remove or rename
+/etc/inputrc, set INPUTRC=~/.inputrc in ~/.bashrc (or .bash_profile,
+but make sure you export it if you do), remove the assignment to
+INPUTRC from /etc/profile, add
+
+ set keymap emacs
+
+to the beginning of /etc/inputrc, or bracket the key bindings in
+/etc/inputrc with these lines
+
+ $if mode=emacs
+ [...]
+ $endif
+
+F7) Why do bash-2.05a and bash-2.05b fail to compile `printf.def' on
+ HP/UX 11.x?
+
+HP/UX's support for long double is imperfect at best.
+
+GCC will support it without problems, but the HP C library functions
+like strtold(3) and printf(3) don't actually work with long doubles.
+HP implemented a `long_double' type as a 4-element array of 32-bit
+ints, and that is what the library functions use. The ANSI C
+`long double' type is a 128-bit floating point scalar.
+
+The easiest fix, until HP fixes things up, is to edit the generated
+config.h and #undef the HAVE_LONG_DOUBLE line. After doing that,
+the compilation should complete successfully.
+
+Section G: How can I get bash to do certain common things?
+
+G1) How can I get bash to read and display eight-bit characters?
+
+This is a process requiring several steps.
+
+First, you must ensure that the `physical' data path is a full eight
+bits. For xterms, for example, the `vt100' resources `eightBitInput'
+and `eightBitOutput' should be set to `true'.
+
+Once you have set up an eight-bit path, you must tell the kernel and
+tty driver to leave the eighth bit of characters alone when processing
+keyboard input. Use `stty' to do this:
+
+ stty cs8 -istrip -parenb
+
+For old BSD-style systems, you can use
+
+ stty pass8
+
+You may also need
+
+ stty even odd
+
+Finally, you need to tell readline that you will be inputting and
+displaying eight-bit characters. You use readline variables to do
+this. These variables can be set in your .inputrc or using the bash
+`bind' builtin. Here's an example using `bind':
+
+ bash$ bind 'set convert-meta off'
+ bash$ bind 'set meta-flag on'
+ bash$ bind 'set output-meta on'
+
+The `set' commands between the single quotes may also be placed
+in ~/.inputrc.
+
+The script examples/scripts.noah/meta.bash encapsulates the bind
+commands in a shell function.
+
+G2) How do I write a function `x' to replace builtin command `x', but
+ still invoke the command from within the function?
+
+This is why the `command' and `builtin' builtins exist. The
+`command' builtin executes the command supplied as its first
+argument, skipping over any function defined with that name. The
+`builtin' builtin executes the builtin command given as its first
+argument directly.
+
+For example, to write a function to replace `cd' that writes the
+hostname and current directory to an xterm title bar, use
+something like the following:
+
+ cd()
+ {
+ builtin cd "$@" && xtitle "$HOST: $PWD"
+ }
+
+This could also be written using `command' instead of `builtin';
+the version above is marginally more efficient.
+
+G3) How can I find the value of a shell variable whose name is the value
+ of another shell variable?
+
+Versions of Bash newer than Bash-2.0 support this directly. You can use
+
+ ${!var}
+
+For example, the following sequence of commands will echo `z':
+
+ var1=var2
+ var2=z
+ echo ${!var1}
+
+For sh compatibility, use the `eval' builtin. The important
+thing to remember is that `eval' expands the arguments you give
+it again, so you need to quote the parts of the arguments that
+you want `eval' to act on.
+
+For example, this expression prints the value of the last positional
+parameter:
+
+ eval echo \"\$\{$#\}\"
+
+The expansion of the quoted portions of this expression will be
+deferred until `eval' runs, while the `$#' will be expanded
+before `eval' is executed. In versions of bash later than bash-2.0,
+
+ echo ${!#}
+
+does the same thing.
+
+This is not the same thing as ksh93 `nameref' variables, though the syntax
+is similar. I may add namerefs in a future bash version.
+
+G4) How can I make the bash `time' reserved word print timing output that
+ looks like the output from my system's /usr/bin/time?
+
+The bash command timing code looks for a variable `TIMEFORMAT' and
+uses its value as a format string to decide how to display the
+timing statistics.
+
+The value of TIMEFORMAT is a string with `%' escapes expanded in a
+fashion similar in spirit to printf(3). The manual page explains
+the meanings of the escape sequences in the format string.
+
+If TIMEFORMAT is not set, bash acts as if the following assignment had
+been performed:
+
+ TIMEFORMAT=$'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'
+
+The POSIX.2 default time format (used by `time -p command') is
+
+ TIMEFORMAT=$'real %2R\nuser %2U\nsys %2S'
+
+The BSD /usr/bin/time format can be emulated with:
+
+ TIMEFORMAT=$'\t%1R real\t%1U user\t%1S sys'
+
+The System V /usr/bin/time format can be emulated with:
+
+ TIMEFORMAT=$'\nreal\t%1R\nuser\t%1U\nsys\t%1S'
+
+The ksh format can be emulated with:
+
+ TIMEFORMAT=$'\nreal\t%2lR\nuser\t%2lU\nsys\t%2lS'
+
+G5) How do I get the current directory into my prompt?
+
+Bash provides a number of backslash-escape sequences which are expanded
+when the prompt string (PS1 or PS2) is displayed. The full list is in
+the manual page.
+
+The \w expansion gives the full pathname of the current directory, with
+a tilde (`~') substituted for the current value of $HOME. The \W
+expansion gives the basename of the current directory. To put the full
+pathname of the current directory into the path without any tilde
+subsitution, use $PWD. Here are some examples:
+
+ PS1='\w$ ' # current directory with tilde
+ PS1='\W$ ' # basename of current directory
+ PS1='$PWD$ ' # full pathname of current directory
+
+The single quotes are important in the final example to prevent $PWD from
+being expanded when the assignment to PS1 is performed.
+
+G6) How can I rename "*.foo" to "*.bar"?
+
+Use the pattern removal functionality described in D3. The following `for'
+loop will do the trick:
+
+ for f in *.foo; do
+ mv $f ${f%foo}bar
+ done
+
+G7) How can I translate a filename from uppercase to lowercase?
+
+The script examples/functions/lowercase, originally written by John DuBois,
+will do the trick. The converse is left as an exercise.
+
+G8) How can I write a filename expansion (globbing) pattern that will match
+ all files in the current directory except "." and ".."?
+
+You must have set the `extglob' shell option using `shopt -s extglob' to use
+this:
+
+ echo .!(.|) *
+
+A solution that works without extended globbing is given in the Unix Shell
+FAQ, posted periodically to comp.unix.shell.
+
+Section H: Where do I go from here?
+
+H1) How do I report bugs in bash, and where should I look for fixes and
+ advice?
+
+Use the `bashbug' script to report bugs. It is built and
+installed at the same time as bash. It provides a standard
+template for reporting a problem and automatically includes
+information about your configuration and build environment.
+
+`bashbug' sends its reports to bug-bash@gnu.org, which
+is a large mailing list gatewayed to the usenet newsgroup gnu.bash.bug.
+
+Bug fixes, answers to questions, and announcements of new releases
+are all posted to gnu.bash.bug. Discussions concerning bash features
+and problems also take place there.
+
+To reach the bash maintainers directly, send mail to
+bash-maintainers@gnu.org.
+
+H2) What kind of bash documentation is there?
+
+First, look in the doc directory in the bash distribution. It should
+contain at least the following files:
+
+bash.1 an extensive, thorough Unix-style manual page
+builtins.1 a manual page covering just bash builtin commands
+bashref.texi a reference manual in GNU tex`info format
+bashref.info an info version of the reference manual
+FAQ this file
+article.ms text of an article written for The Linux Journal
+readline.3 a man page describing readline
+
+Postscript, HTML, and ASCII files created from the above source are
+available in the documentation distribution.
+
+There is additional documentation available for anonymous FTP from host
+ftp.cwru.edu in the `pub/bash' directory.
+
+Cameron Newham and Bill Rosenblatt have written a book on bash, published
+by O'Reilly and Associates. The book is based on Bill Rosenblatt's Korn
+Shell book. The title is ``Learning the Bash Shell'', and the ISBN number
+of the third edition, published in March, 2005, is 0-596-00965-8. Look for
+it in fine bookstores near you. This edition of the book has been updated
+to cover bash-3.0.
+
+The GNU Bash Reference Manual has been published as a printed book by
+Network Theory Ltd (Paperback, ISBN: 0-9541617-7-7, Nov. 2006). It covers
+bash-3.2 and is available from most online bookstores (see
+http://www.network-theory.co.uk/bash/manual/ for details). The publisher
+will donate $1 to the Free Software Foundation for each copy sold.
+
+Arnold Robbins and Nelson Beebe have written ``Classic Shell Scripting'',
+published by O'Reilly. The first edition, with ISBN number 0-596-00595-4,
+was published in May, 2005.
+
+Chris F. A. Johnson, a frequent contributor to comp.unix.shell and
+gnu.bash.bug, has written ``Shell Scripting Recipes: A Problem-Solution
+Approach,'' a new book on shell scripting, concentrating on features of
+the POSIX standard helpful to shell script writers. The first edition from
+Apress, with ISBN number 1-59059-471-1, was published in May, 2005.
+
+H3) What's coming in future versions?
+
+These are features I hope to include in a future version of bash.
+
+Rocky Bernstein's bash debugger (support is included with bash-3.0)
+associative arrays
+co-processes, but with a new-style syntax that looks like function declaration
+
+H4) What's on the bash `wish list' for future versions?
+
+These are features that may or may not appear in a future version of bash.
+
+breaking some of the shell functionality into embeddable libraries
+a module system like zsh's, using dynamic loading like builtins
+a bash programmer's guide with a chapter on creating loadable builtins
+a better loadable interface to perl with access to the shell builtins and
+ variables (contributions gratefully accepted)
+ksh93-like `nameref' variables
+ksh93-like `xx.yy' variables (including some of the .sh.* variables) and
+ associated disipline functions
+Some of the new ksh93 pattern matching operators, like backreferencing
+
+H5) When will the next release appear?
+
+The next version will appear sometime in 2007. Never make predictions.
+
+This document is Copyright 1995-2006 by Chester Ramey.
+
+Permission is hereby granted, without written agreement and
+without license or royalty fees, to use, copy, and distribute
+this document for any purpose, provided that the above copyright
+notice appears in all copies of this document and that the
+contents of this document remain unaltered.
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