This is bash.info, produced by makeinfo version 6.8 from bashref.texi.
This text is a brief description of the features that are present in the
-Bash shell (version 5.2, 27 December 2022).
+Bash shell (version 5.2, 7 February 2023).
- This is Edition 5.2, last updated 27 December 2022, of 'The GNU Bash
+ This is Edition 5.2, last updated 7 February 2023, of 'The GNU Bash
Reference Manual', for 'Bash', Version 5.2.
- Copyright (C) 1988-2022 Free Software Foundation, Inc.
+ Copyright (C) 1988-2023 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
*************
This text is a brief description of the features that are present in the
-Bash shell (version 5.2, 27 December 2022). The Bash home page is
+Bash shell (version 5.2, 7 February 2023). The Bash home page is
<http://www.gnu.org/software/bash/>.
- This is Edition 5.2, last updated 27 December 2022, of 'The GNU Bash
+ This is Edition 5.2, last updated 7 February 2023, of 'The GNU Bash
Reference Manual', for 'Bash', Version 5.2.
Bash contains features that appear in other popular shells, and some
----------------------------------
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.
+command and an optional list of arguments, the shell performs the
+following actions.
1. If the command name contains no slashes, the shell attempts to
locate it. If there exists a shell function by that name, that
children. The return status is zero.
'trap'
- trap [-lp] [ACTION] [SIGSPEC ...]
+ trap [-Plp] [ACTION] [SIGSPEC ...]
The ACTION is a command that is read and executed when the shell
receives signal SIGSPEC. If ACTION is absent (and there is a
displays the trap commands associated with each SIGSPEC, or, if no
SIGSPECs are supplied, for all trapped signals, as a set of 'trap'
commands that can be reused as shell input to restore the current
- signal dispositions.
+ signal dispositions. The '-P' option behaves similarly, but
+ displays only the actions associated with each SIGSPEC argument.
+ '-P' requires at least one SIGSPEC argument. The '-P' or '-p'
+ options to 'trap' may be used in a subshell environment (e.g.,
+ command substitution) and, as long as they are used before 'trap'
+ is used to change a signal's handling, will display the state of
+ its parent's traps.
The '-l' option causes 'trap' to print a list of signal names and
their corresponding numbers. Each SIGSPEC is either a signal name
Bash Builtins::).
'%q'
Causes 'printf' to output the corresponding ARGUMENT in a
- format that can be reused as shell input.
+ format that can be reused as shell input. '%q' and '%Q'P use
+ the ANSI-C quoting style (*note ANSI-C Quoting::) if any
+ characters in the argument string require it, and backslash
+ quoting otherwise. If the format string uses the 'printf'
+ ALTERNATE FORM, these two formats quote the argument string
+ using single quotes.
+
'%Q'
like '%q', but applies any supplied precision to the ARGUMENT
before quoting it.
conversion behaves as if -1 had been given. This is an
exception to the usual 'printf' behavior.
- The %b, %q, and %T directives all use the field width and precision
- arguments from the format specification and write that many bytes
- from (or use that wide a field for) the expanded argument, which
- usually contains more characters than the original.
+ The %b, %q, and %T format specifiers all use the field width and
+ precision arguments from the format specification and write that
+ many bytes from (or use that wide a field for) the expanded
+ argument, which usually contains more characters than the original.
The %n format specifier accepts a corresponding argument that is
treated as a shell variable name.
+ The %s and %c format specifiers accept an l (long) modifier, which
+ forces them to convert the argument string to a wide-character
+ string and apply any supplied field width and precision in terms of
+ characters, not bytes.
+
Arguments to non-string format specifiers are treated as C language
constants, except that a leading plus or minus sign is allowed, and
if the leading character is a single or double quote, the value is
'-x'
Print a trace of simple commands, 'for' commands, 'case'
commands, 'select' commands, and arithmetic 'for' commands and
- their arguments or associated word lists after they are
- expanded and before they are executed. The value of the 'PS4'
- variable is expanded and the resultant value is printed before
+ their arguments or associated word lists to standard error
+ after they are expanded and before they are executed. The
+ shell prints the expanded value of the 'PS4' variable before
the command and its expanded arguments.
'-B'
16. Function names may not be the same as one of the POSIX special
builtins.
- 17. POSIX special builtins are found before shell functions during
+ 17. Even if a shell function whose name contains a slash was defined
+ before entering POSIX mode, the shell will not execute a function
+ whose name contains one or more slashes.
+
+ 18. POSIX special builtins are found before shell functions during
command lookup.
- 18. When printing shell function definitions (e.g., by 'type'), Bash
+ 19. When printing shell function definitions (e.g., by 'type'), Bash
does not print the 'function' keyword.
- 19. Literal tildes that appear as the first character in elements of
+ 20. Literal tildes that appear as the first character in elements of
the 'PATH' variable are not expanded as described above under *note
Tilde Expansion::.
- 20. The 'time' reserved word may be used by itself as a command. When
+ 21. The 'time' reserved word may be used by itself as a command. When
used in this way, it displays timing statistics for the shell and
its completed children. The 'TIMEFORMAT' variable controls the
format of the timing information.
- 21. When parsing and expanding a ${...} expansion that appears within
+ 22. When parsing and expanding a ${...} expansion that appears within
double quotes, single quotes are no longer special and cannot be
used to quote a closing brace or other special character, unless
the operator is one of those defined to perform pattern removal.
In this case, they do not have to appear as matched pairs.
- 22. The parser does not recognize 'time' as a reserved word if the
+ 23. The parser does not recognize 'time' as a reserved word if the
next token begins with a '-'.
- 23. The '!' character does not introduce history expansion within a
+ 24. The '!' character does not introduce history expansion within a
double-quoted string, even if the 'histexpand' option is enabled.
- 24. If a POSIX special builtin returns an error status, a
+ 25. If a POSIX special builtin returns an error status, a
non-interactive shell exits. The fatal errors are those listed in
the POSIX standard, and include things like passing incorrect
options, redirection errors, variable assignment errors for
assignments preceding the command name, and so on.
- 25. The 'unset' builtin with the '-v' option specified returns a fatal
+ 26. The 'unset' builtin with the '-v' option specified returns a fatal
error if it attempts to unset a 'readonly' or 'non-unsettable'
variable, or encounters a variable name argument that is an invalid
identifier, which causes a non-interactive shell to exit.
- 26. A non-interactive shell exits with an error status if a variable
+ 27. A non-interactive shell exits with an error status if a variable
assignment error occurs when no command name follows the assignment
statements. A variable assignment error occurs, for example, when
trying to assign a value to a readonly variable.
- 27. A non-interactive shell exits with an error status if a variable
+ 28. A non-interactive shell exits with an error status if a variable
assignment error occurs in an assignment statement preceding a
special builtin, but not with any other simple command. For any
other simple command, the shell aborts execution of that command,
perform any further processing of the command in which the error
occurred").
- 28. A non-interactive shell exits with an error status if the
+ 29. A non-interactive shell exits with an error status if the
iteration variable in a 'for' statement or the selection variable
in a 'select' statement is a readonly variable.
- 29. Non-interactive shells exit if FILENAME in '.' FILENAME is not
+ 30. Non-interactive shells exit if FILENAME in '.' FILENAME is not
found.
- 30. Non-interactive shells exit if a syntax error in an arithmetic
+ 31. Non-interactive shells exit if a syntax error in an arithmetic
expansion results in an invalid expression.
- 31. Non-interactive shells exit if a parameter expansion error occurs.
+ 32. Non-interactive shells exit if a parameter expansion error occurs.
- 32. Non-interactive shells exit if there is a syntax error in a script
+ 33. Non-interactive shells exit if there is a syntax error in a script
read with the '.' or 'source' builtins, or in a string processed by
the 'eval' builtin.
- 33. While variable indirection is available, it may not be applied to
+ 34. While variable indirection is available, it may not be applied to
the '#' and '?' special parameters.
- 34. Expanding the '*' special parameter in a pattern context where the
+ 35. Expanding the '*' special parameter in a pattern context where the
expansion is double-quoted does not treat the '$*' as if it were
double-quoted.
- 35. Assignment statements preceding POSIX special builtins persist in
+ 36. Assignment statements preceding POSIX special builtins persist in
the shell environment after the builtin completes.
- 36. The 'command' builtin does not prevent builtins that take
+ 37. The 'command' builtin does not prevent builtins that take
assignment statements as arguments from expanding them as
assignment statements; when not in POSIX mode, assignment builtins
lose their assignment statement expansion properties when preceded
by 'command'.
- 37. The 'bg' builtin uses the required format to describe each job
+ 38. The 'bg' builtin uses the required format to describe each job
placed in the background, which does not include an indication of
whether the job is the current or previous job.
- 38. The output of 'kill -l' prints all the signal names on a single
+ 39. The output of 'kill -l' prints all the signal names on a single
line, separated by spaces, without the 'SIG' prefix.
- 39. The 'kill' builtin does not accept signal names with a 'SIG'
+ 40. The 'kill' builtin does not accept signal names with a 'SIG'
prefix.
- 40. The 'export' and 'readonly' builtin commands display their output
+ 41. The 'export' and 'readonly' builtin commands display their output
in the format required by POSIX.
- 41. The 'trap' builtin displays signal names without the leading
+ 42. The 'trap' builtin displays signal names without the leading
'SIG'.
- 42. The 'trap' builtin doesn't check the first argument for a possible
+ 43. The 'trap' builtin doesn't check the first argument for a possible
signal specification and revert the signal handling to the original
disposition if it is, unless that argument consists solely of
digits and is a valid signal number. If users want to reset the
handler for a given signal to the original disposition, they should
use '-' as the first argument.
- 43. 'trap -p' without arguments displays signals whose dispositions
+ 44. 'trap -p' without arguments displays signals whose dispositions
are set to SIG_DFL and those that were ignored when the shell
started, not just trapped signals.
- 44. The '.' and 'source' builtins do not search the current directory
+ 45. The '.' and 'source' builtins do not search the current directory
for the filename argument if it is not found by searching 'PATH'.
- 45. Enabling POSIX mode has the effect of setting the
+ 46. Enabling POSIX mode has the effect of setting the
'inherit_errexit' option, so subshells spawned to execute command
substitutions inherit the value of the '-e' option from the parent
shell. When the 'inherit_errexit' option is not enabled, Bash
clears the '-e' option in such subshells.
- 46. Enabling POSIX mode has the effect of setting the 'shift_verbose'
+ 47. Enabling POSIX mode has the effect of setting the 'shift_verbose'
option, so numeric arguments to 'shift' that exceed the number of
positional parameters will result in an error message.
- 47. When the 'alias' builtin displays alias definitions, it does not
+ 48. When the 'alias' builtin displays alias definitions, it does not
display them with a leading 'alias ' unless the '-p' option is
supplied.
- 48. When the 'set' builtin is invoked without options, it does not
+ 49. When the 'set' builtin is invoked without options, it does not
display shell function names and definitions.
- 49. When the 'set' builtin is invoked without options, it displays
+ 50. When the 'set' builtin is invoked without options, it displays
variable values without quotes, unless they contain shell
metacharacters, even if the result contains nonprinting characters.
- 50. When the 'cd' builtin is invoked in logical mode, and the pathname
+ 51. When the 'cd' builtin is invoked in logical mode, and the pathname
constructed from '$PWD' and the directory name supplied as an
argument does not refer to an existing directory, 'cd' will fail
instead of falling back to physical mode.
- 51. When the 'cd' builtin cannot change a directory because the length
+ 52. When the 'cd' builtin cannot change a directory because the length
of the pathname constructed from '$PWD' and the directory name
supplied as an argument exceeds 'PATH_MAX' when all symbolic links
are expanded, 'cd' will fail instead of attempting to use only the
supplied directory name.
- 52. The 'pwd' builtin verifies that the value it prints is the same as
+ 53. The 'pwd' builtin verifies that the value it prints is the same as
the current directory, even if it is not asked to check the file
system with the '-P' option.
- 53. When listing the history, the 'fc' builtin does not include an
+ 54. When listing the history, the 'fc' builtin does not include an
indication of whether or not a history entry has been modified.
- 54. The default editor used by 'fc' is 'ed'.
+ 55. The default editor used by 'fc' is 'ed'.
+
+ 56. If there are too many arguments supplied to 'fc -s', 'fc' prints
+ an error message and returns failure.
- 55. The 'type' and 'command' builtins will not report a non-executable
+ 57. The 'type' and 'command' builtins will not report a non-executable
file as having been found, though the shell will attempt to execute
such a file if it is the only so-named file found in '$PATH'.
- 56. The 'vi' editing mode will invoke the 'vi' editor directly when
+ 58. The 'vi' editing mode will invoke the 'vi' editor directly when
the 'v' command is run, instead of checking '$VISUAL' and
'$EDITOR'.
- 57. When the 'xpg_echo' option is enabled, Bash does not attempt to
+ 59. When the 'xpg_echo' option is enabled, Bash does not attempt to
interpret any arguments to 'echo' as options. Each argument is
displayed, after escape characters are converted.
- 58. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
+ 60. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
and '-f' options.
- 59. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
+ 61. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
interrupt the 'wait' builtin and cause it to return immediately.
The trap command is run once for each child that exits.
- 60. The 'read' builtin may be interrupted by a signal for which a trap
+ 62. The 'read' builtin may be interrupted by a signal for which a trap
has been set. If Bash receives a trapped signal while executing
'read', the trap handler executes and 'read' returns an exit status
greater than 128.
- 61. The 'printf' builtin uses 'double' (via 'strtod') to convert
+ 63. The 'printf' builtin uses 'double' (via 'strtod') to convert
arguments corresponding to floating point conversion specifiers,
instead of 'long double' if it's available. The 'L' length
modifier forces 'printf' to use 'long double' if it's available.
- 62. Bash removes an exited background process's status from the list
+ 64. Bash removes an exited background process's status from the list
of such statuses after the 'wait' builtin is used to obtain it.
- 63. A double quote character ('"') is treated specially when it
+ 65. A double quote character ('"') is treated specially when it
appears in a backquoted command substitution in the body of a
here-document that undergoes expansion. That means, for example,
that a backslash preceding a double quote character will escape it
(line 69)
* pwd: Bourne Shell Builtins.
(line 212)
-* read: Bash Builtins. (line 492)
-* readarray: Bash Builtins. (line 589)
+* read: Bash Builtins. (line 503)
+* readarray: Bash Builtins. (line 600)
* readonly: Bourne Shell Builtins.
(line 222)
* return: Bourne Shell Builtins.
* shift: Bourne Shell Builtins.
(line 262)
* shopt: The Shopt Builtin. (line 9)
-* source: Bash Builtins. (line 598)
+* source: Bash Builtins. (line 609)
* suspend: Job Control Builtins.
(line 116)
* test: Bourne Shell Builtins.
(line 360)
* trap: Bourne Shell Builtins.
(line 366)
-* type: Bash Builtins. (line 603)
-* typeset: Bash Builtins. (line 641)
-* ulimit: Bash Builtins. (line 647)
+* type: Bash Builtins. (line 614)
+* typeset: Bash Builtins. (line 652)
+* ulimit: Bash Builtins. (line 658)
* umask: Bourne Shell Builtins.
- (line 422)
-* unalias: Bash Builtins. (line 753)
+ (line 428)
+* unalias: Bash Builtins. (line 764)
* unset: Bourne Shell Builtins.
- (line 440)
+ (line 446)
* wait: Job Control Builtins.
(line 76)
\1f
Tag Table:
-Node: Top\7f894
-Node: Introduction\7f2811
-Node: What is Bash?\7f3024
-Node: What is a shell?\7f4135
-Node: Definitions\7f6670
-Node: Basic Shell Features\7f9618
-Node: Shell Syntax\7f10834
-Node: Shell Operation\7f11857
-Node: Quoting\7f13147
-Node: Escape Character\7f14448
-Node: Single Quotes\7f14930
-Node: Double Quotes\7f15275
-Node: ANSI-C Quoting\7f16550
-Node: Locale Translation\7f17857
-Node: Creating Internationalized Scripts\7f19165
-Node: Comments\7f23279
-Node: Shell Commands\7f23894
-Node: Reserved Words\7f24829
-Node: Simple Commands\7f25582
-Node: Pipelines\7f26233
-Node: Lists\7f29229
-Node: Compound Commands\7f31021
-Node: Looping Constructs\7f32030
-Node: Conditional Constructs\7f34522
-Node: Command Grouping\7f49007
-Node: Coprocesses\7f50482
-Node: GNU Parallel\7f53142
-Node: Shell Functions\7f54056
-Node: Shell Parameters\7f61938
-Node: Positional Parameters\7f66323
-Node: Special Parameters\7f67222
-Node: Shell Expansions\7f70433
-Node: Brace Expansion\7f72557
-Node: Tilde Expansion\7f75288
-Node: Shell Parameter Expansion\7f77906
-Node: Command Substitution\7f96305
-Node: Arithmetic Expansion\7f97657
-Node: Process Substitution\7f98622
-Node: Word Splitting\7f99739
-Node: Filename Expansion\7f101680
-Node: Pattern Matching\7f104426
-Node: Quote Removal\7f109425
-Node: Redirections\7f109717
-Node: Executing Commands\7f119374
-Node: Simple Command Expansion\7f120041
-Node: Command Search and Execution\7f122148
-Node: Command Execution Environment\7f124523
-Node: Environment\7f127555
-Node: Exit Status\7f129215
-Node: Signals\7f130996
-Node: Shell Scripts\7f134442
-Node: Shell Builtin Commands\7f137466
-Node: Bourne Shell Builtins\7f139501
-Node: Bash Builtins\7f161283
-Node: Modifying Shell Behavior\7f192671
-Node: The Set Builtin\7f193013
-Node: The Shopt Builtin\7f203611
-Node: Special Builtins\7f219520
-Node: Shell Variables\7f220496
-Node: Bourne Shell Variables\7f220930
-Node: Bash Variables\7f223031
-Node: Bash Features\7f255843
-Node: Invoking Bash\7f256853
-Node: Bash Startup Files\7f262863
-Node: Interactive Shells\7f267991
-Node: What is an Interactive Shell?\7f268399
-Node: Is this Shell Interactive?\7f269045
-Node: Interactive Shell Behavior\7f269857
-Node: Bash Conditional Expressions\7f273483
-Node: Shell Arithmetic\7f278122
-Node: Aliases\7f281063
-Node: Arrays\7f283673
-Node: The Directory Stack\7f290061
-Node: Directory Stack Builtins\7f290842
-Node: Controlling the Prompt\7f295099
-Node: The Restricted Shell\7f298061
-Node: Bash POSIX Mode\7f300668
-Node: Shell Compatibility Mode\7f313227
-Node: Job Control\7f321791
-Node: Job Control Basics\7f322248
-Node: Job Control Builtins\7f327247
-Node: Job Control Variables\7f333039
-Node: Command Line Editing\7f334192
-Node: Introduction and Notation\7f335860
-Node: Readline Interaction\7f337480
-Node: Readline Bare Essentials\7f338668
-Node: Readline Movement Commands\7f340454
-Node: Readline Killing Commands\7f341411
-Node: Readline Arguments\7f343329
-Node: Searching\7f344370
-Node: Readline Init File\7f346553
-Node: Readline Init File Syntax\7f347811
-Node: Conditional Init Constructs\7f371394
-Node: Sample Init File\7f375587
-Node: Bindable Readline Commands\7f378708
-Node: Commands For Moving\7f379909
-Node: Commands For History\7f381957
-Node: Commands For Text\7f386948
-Node: Commands For Killing\7f390594
-Node: Numeric Arguments\7f393624
-Node: Commands For Completion\7f394760
-Node: Keyboard Macros\7f398948
-Node: Miscellaneous Commands\7f399633
-Node: Readline vi Mode\7f405575
-Node: Programmable Completion\7f406479
-Node: Programmable Completion Builtins\7f414256
-Node: A Programmable Completion Example\7f425005
-Node: Using History Interactively\7f430250
-Node: Bash History Facilities\7f430931
-Node: Bash History Builtins\7f433933
-Node: History Interaction\7f438954
-Node: Event Designators\7f442571
-Node: Word Designators\7f443922
-Node: Modifiers\7f445679
-Node: Installing Bash\7f447484
-Node: Basic Installation\7f448618
-Node: Compilers and Options\7f452337
-Node: Compiling For Multiple Architectures\7f453075
-Node: Installation Names\7f454764
-Node: Specifying the System Type\7f456870
-Node: Sharing Defaults\7f457584
-Node: Operation Controls\7f458254
-Node: Optional Features\7f459209
-Node: Reporting Bugs\7f470425
-Node: Major Differences From The Bourne Shell\7f471766
-Node: GNU Free Documentation License\7f488612
-Node: Indexes\7f513786
-Node: Builtin Index\7f514237
-Node: Reserved Word Index\7f521061
-Node: Variable Index\7f523506
-Node: Function Index\7f540277
-Node: Concept Index\7f554058
+Node: Top\7f892
+Node: Introduction\7f2807
+Node: What is Bash?\7f3020
+Node: What is a shell?\7f4131
+Node: Definitions\7f6666
+Node: Basic Shell Features\7f9614
+Node: Shell Syntax\7f10830
+Node: Shell Operation\7f11853
+Node: Quoting\7f13143
+Node: Escape Character\7f14444
+Node: Single Quotes\7f14926
+Node: Double Quotes\7f15271
+Node: ANSI-C Quoting\7f16546
+Node: Locale Translation\7f17853
+Node: Creating Internationalized Scripts\7f19161
+Node: Comments\7f23275
+Node: Shell Commands\7f23890
+Node: Reserved Words\7f24825
+Node: Simple Commands\7f25578
+Node: Pipelines\7f26229
+Node: Lists\7f29225
+Node: Compound Commands\7f31017
+Node: Looping Constructs\7f32026
+Node: Conditional Constructs\7f34518
+Node: Command Grouping\7f49003
+Node: Coprocesses\7f50478
+Node: GNU Parallel\7f53138
+Node: Shell Functions\7f54052
+Node: Shell Parameters\7f61934
+Node: Positional Parameters\7f66319
+Node: Special Parameters\7f67218
+Node: Shell Expansions\7f70429
+Node: Brace Expansion\7f72553
+Node: Tilde Expansion\7f75284
+Node: Shell Parameter Expansion\7f77902
+Node: Command Substitution\7f96301
+Node: Arithmetic Expansion\7f97653
+Node: Process Substitution\7f98618
+Node: Word Splitting\7f99735
+Node: Filename Expansion\7f101676
+Node: Pattern Matching\7f104422
+Node: Quote Removal\7f109421
+Node: Redirections\7f109713
+Node: Executing Commands\7f119370
+Node: Simple Command Expansion\7f120037
+Node: Command Search and Execution\7f122144
+Node: Command Execution Environment\7f124528
+Node: Environment\7f127560
+Node: Exit Status\7f129220
+Node: Signals\7f131001
+Node: Shell Scripts\7f134447
+Node: Shell Builtin Commands\7f137471
+Node: Bourne Shell Builtins\7f139506
+Node: Bash Builtins\7f161701
+Node: Modifying Shell Behavior\7f193666
+Node: The Set Builtin\7f194008
+Node: The Shopt Builtin\7f204603
+Node: Special Builtins\7f220512
+Node: Shell Variables\7f221488
+Node: Bourne Shell Variables\7f221922
+Node: Bash Variables\7f224023
+Node: Bash Features\7f256835
+Node: Invoking Bash\7f257845
+Node: Bash Startup Files\7f263855
+Node: Interactive Shells\7f268983
+Node: What is an Interactive Shell?\7f269391
+Node: Is this Shell Interactive?\7f270037
+Node: Interactive Shell Behavior\7f270849
+Node: Bash Conditional Expressions\7f274475
+Node: Shell Arithmetic\7f279114
+Node: Aliases\7f282055
+Node: Arrays\7f284665
+Node: The Directory Stack\7f291053
+Node: Directory Stack Builtins\7f291834
+Node: Controlling the Prompt\7f296091
+Node: The Restricted Shell\7f299053
+Node: Bash POSIX Mode\7f301660
+Node: Shell Compatibility Mode\7f314523
+Node: Job Control\7f323087
+Node: Job Control Basics\7f323544
+Node: Job Control Builtins\7f328543
+Node: Job Control Variables\7f334335
+Node: Command Line Editing\7f335488
+Node: Introduction and Notation\7f337156
+Node: Readline Interaction\7f338776
+Node: Readline Bare Essentials\7f339964
+Node: Readline Movement Commands\7f341750
+Node: Readline Killing Commands\7f342707
+Node: Readline Arguments\7f344625
+Node: Searching\7f345666
+Node: Readline Init File\7f347849
+Node: Readline Init File Syntax\7f349107
+Node: Conditional Init Constructs\7f372690
+Node: Sample Init File\7f376883
+Node: Bindable Readline Commands\7f380004
+Node: Commands For Moving\7f381205
+Node: Commands For History\7f383253
+Node: Commands For Text\7f388244
+Node: Commands For Killing\7f391890
+Node: Numeric Arguments\7f394920
+Node: Commands For Completion\7f396056
+Node: Keyboard Macros\7f400244
+Node: Miscellaneous Commands\7f400929
+Node: Readline vi Mode\7f406871
+Node: Programmable Completion\7f407775
+Node: Programmable Completion Builtins\7f415552
+Node: A Programmable Completion Example\7f426301
+Node: Using History Interactively\7f431546
+Node: Bash History Facilities\7f432227
+Node: Bash History Builtins\7f435229
+Node: History Interaction\7f440250
+Node: Event Designators\7f443867
+Node: Word Designators\7f445218
+Node: Modifiers\7f446975
+Node: Installing Bash\7f448780
+Node: Basic Installation\7f449914
+Node: Compilers and Options\7f453633
+Node: Compiling For Multiple Architectures\7f454371
+Node: Installation Names\7f456060
+Node: Specifying the System Type\7f458166
+Node: Sharing Defaults\7f458880
+Node: Operation Controls\7f459550
+Node: Optional Features\7f460505
+Node: Reporting Bugs\7f471721
+Node: Major Differences From The Bourne Shell\7f473062
+Node: GNU Free Documentation License\7f489908
+Node: Indexes\7f515082
+Node: Builtin Index\7f515533
+Node: Reserved Word Index\7f522357
+Node: Variable Index\7f524802
+Node: Function Index\7f541573
+Node: Concept Index\7f555354
\1f
End Tag Table
bashref.texi.
This text is a brief description of the features that are present in the
-Bash shell (version 5.2, 27 January 2023).
+Bash shell (version 5.2, 7 February 2023).
- This is Edition 5.2, last updated 27 January 2023, of 'The GNU Bash
+ This is Edition 5.2, last updated 7 February 2023, of 'The GNU Bash
Reference Manual', for 'Bash', Version 5.2.
Copyright (C) 1988-2023 Free Software Foundation, Inc.
*************
This text is a brief description of the features that are present in the
-Bash shell (version 5.2, 27 January 2023). The Bash home page is
+Bash shell (version 5.2, 7 February 2023). The Bash home page is
<http://www.gnu.org/software/bash/>.
- This is Edition 5.2, last updated 27 January 2023, of 'The GNU Bash
+ This is Edition 5.2, last updated 7 February 2023, of 'The GNU Bash
Reference Manual', for 'Bash', Version 5.2.
Bash contains features that appear in other popular shells, and some
Bash Builtins::).
'%q'
Causes 'printf' to output the corresponding ARGUMENT in a
- format that can be reused as shell input.
+ format that can be reused as shell input. '%q' and '%Q'P use
+ the ANSI-C quoting style (*note ANSI-C Quoting::) if any
+ characters in the argument string require it, and backslash
+ quoting otherwise. If the format string uses the 'printf'
+ ALTERNATE FORM, these two formats quote the argument string
+ using single quotes.
+
'%Q'
like '%q', but applies any supplied precision to the ARGUMENT
before quoting it.
conversion behaves as if -1 had been given. This is an
exception to the usual 'printf' behavior.
- The %b, %q, and %T directives all use the field width and precision
- arguments from the format specification and write that many bytes
- from (or use that wide a field for) the expanded argument, which
- usually contains more characters than the original.
+ The %b, %q, and %T format specifiers all use the field width and
+ precision arguments from the format specification and write that
+ many bytes from (or use that wide a field for) the expanded
+ argument, which usually contains more characters than the original.
The %n format specifier accepts a corresponding argument that is
treated as a shell variable name.
+ The %s and %c format specifiers accept an l (long) modifier, which
+ forces them to convert the argument string to a wide-character
+ string and apply any supplied field width and precision in terms of
+ characters, not bytes.
+
Arguments to non-string format specifiers are treated as C language
constants, except that a leading plus or minus sign is allowed, and
if the leading character is a single or double quote, the value is
16. Function names may not be the same as one of the POSIX special
builtins.
- 17. POSIX special builtins are found before shell functions during
+ 17. Even if a shell function whose name contains a slash was defined
+ before entering POSIX mode, the shell will not execute a function
+ whose name contains one or more slashes.
+
+ 18. POSIX special builtins are found before shell functions during
command lookup.
- 18. When printing shell function definitions (e.g., by 'type'), Bash
+ 19. When printing shell function definitions (e.g., by 'type'), Bash
does not print the 'function' keyword.
- 19. Literal tildes that appear as the first character in elements of
+ 20. Literal tildes that appear as the first character in elements of
the 'PATH' variable are not expanded as described above under *note
Tilde Expansion::.
- 20. The 'time' reserved word may be used by itself as a command. When
+ 21. The 'time' reserved word may be used by itself as a command. When
used in this way, it displays timing statistics for the shell and
its completed children. The 'TIMEFORMAT' variable controls the
format of the timing information.
- 21. When parsing and expanding a ${...} expansion that appears within
+ 22. When parsing and expanding a ${...} expansion that appears within
double quotes, single quotes are no longer special and cannot be
used to quote a closing brace or other special character, unless
the operator is one of those defined to perform pattern removal.
In this case, they do not have to appear as matched pairs.
- 22. The parser does not recognize 'time' as a reserved word if the
+ 23. The parser does not recognize 'time' as a reserved word if the
next token begins with a '-'.
- 23. The '!' character does not introduce history expansion within a
+ 24. The '!' character does not introduce history expansion within a
double-quoted string, even if the 'histexpand' option is enabled.
- 24. If a POSIX special builtin returns an error status, a
+ 25. If a POSIX special builtin returns an error status, a
non-interactive shell exits. The fatal errors are those listed in
the POSIX standard, and include things like passing incorrect
options, redirection errors, variable assignment errors for
assignments preceding the command name, and so on.
- 25. The 'unset' builtin with the '-v' option specified returns a fatal
+ 26. The 'unset' builtin with the '-v' option specified returns a fatal
error if it attempts to unset a 'readonly' or 'non-unsettable'
variable, or encounters a variable name argument that is an invalid
identifier, which causes a non-interactive shell to exit.
- 26. A non-interactive shell exits with an error status if a variable
+ 27. A non-interactive shell exits with an error status if a variable
assignment error occurs when no command name follows the assignment
statements. A variable assignment error occurs, for example, when
trying to assign a value to a readonly variable.
- 27. A non-interactive shell exits with an error status if a variable
+ 28. A non-interactive shell exits with an error status if a variable
assignment error occurs in an assignment statement preceding a
special builtin, but not with any other simple command. For any
other simple command, the shell aborts execution of that command,
perform any further processing of the command in which the error
occurred").
- 28. A non-interactive shell exits with an error status if the
+ 29. A non-interactive shell exits with an error status if the
iteration variable in a 'for' statement or the selection variable
in a 'select' statement is a readonly variable.
- 29. Non-interactive shells exit if FILENAME in '.' FILENAME is not
+ 30. Non-interactive shells exit if FILENAME in '.' FILENAME is not
found.
- 30. Non-interactive shells exit if a syntax error in an arithmetic
+ 31. Non-interactive shells exit if a syntax error in an arithmetic
expansion results in an invalid expression.
- 31. Non-interactive shells exit if a parameter expansion error occurs.
+ 32. Non-interactive shells exit if a parameter expansion error occurs.
- 32. Non-interactive shells exit if there is a syntax error in a script
+ 33. Non-interactive shells exit if there is a syntax error in a script
read with the '.' or 'source' builtins, or in a string processed by
the 'eval' builtin.
- 33. While variable indirection is available, it may not be applied to
+ 34. While variable indirection is available, it may not be applied to
the '#' and '?' special parameters.
- 34. Expanding the '*' special parameter in a pattern context where the
+ 35. Expanding the '*' special parameter in a pattern context where the
expansion is double-quoted does not treat the '$*' as if it were
double-quoted.
- 35. Assignment statements preceding POSIX special builtins persist in
+ 36. Assignment statements preceding POSIX special builtins persist in
the shell environment after the builtin completes.
- 36. The 'command' builtin does not prevent builtins that take
+ 37. The 'command' builtin does not prevent builtins that take
assignment statements as arguments from expanding them as
assignment statements; when not in POSIX mode, assignment builtins
lose their assignment statement expansion properties when preceded
by 'command'.
- 37. The 'bg' builtin uses the required format to describe each job
+ 38. The 'bg' builtin uses the required format to describe each job
placed in the background, which does not include an indication of
whether the job is the current or previous job.
- 38. The output of 'kill -l' prints all the signal names on a single
+ 39. The output of 'kill -l' prints all the signal names on a single
line, separated by spaces, without the 'SIG' prefix.
- 39. The 'kill' builtin does not accept signal names with a 'SIG'
+ 40. The 'kill' builtin does not accept signal names with a 'SIG'
prefix.
- 40. The 'export' and 'readonly' builtin commands display their output
+ 41. The 'export' and 'readonly' builtin commands display their output
in the format required by POSIX.
- 41. The 'trap' builtin displays signal names without the leading
+ 42. The 'trap' builtin displays signal names without the leading
'SIG'.
- 42. The 'trap' builtin doesn't check the first argument for a possible
+ 43. The 'trap' builtin doesn't check the first argument for a possible
signal specification and revert the signal handling to the original
disposition if it is, unless that argument consists solely of
digits and is a valid signal number. If users want to reset the
handler for a given signal to the original disposition, they should
use '-' as the first argument.
- 43. 'trap -p' without arguments displays signals whose dispositions
+ 44. 'trap -p' without arguments displays signals whose dispositions
are set to SIG_DFL and those that were ignored when the shell
started, not just trapped signals.
- 44. The '.' and 'source' builtins do not search the current directory
+ 45. The '.' and 'source' builtins do not search the current directory
for the filename argument if it is not found by searching 'PATH'.
- 45. Enabling POSIX mode has the effect of setting the
+ 46. Enabling POSIX mode has the effect of setting the
'inherit_errexit' option, so subshells spawned to execute command
substitutions inherit the value of the '-e' option from the parent
shell. When the 'inherit_errexit' option is not enabled, Bash
clears the '-e' option in such subshells.
- 46. Enabling POSIX mode has the effect of setting the 'shift_verbose'
+ 47. Enabling POSIX mode has the effect of setting the 'shift_verbose'
option, so numeric arguments to 'shift' that exceed the number of
positional parameters will result in an error message.
- 47. When the 'alias' builtin displays alias definitions, it does not
+ 48. When the 'alias' builtin displays alias definitions, it does not
display them with a leading 'alias ' unless the '-p' option is
supplied.
- 48. When the 'set' builtin is invoked without options, it does not
+ 49. When the 'set' builtin is invoked without options, it does not
display shell function names and definitions.
- 49. When the 'set' builtin is invoked without options, it displays
+ 50. When the 'set' builtin is invoked without options, it displays
variable values without quotes, unless they contain shell
metacharacters, even if the result contains nonprinting characters.
- 50. When the 'cd' builtin is invoked in logical mode, and the pathname
+ 51. When the 'cd' builtin is invoked in logical mode, and the pathname
constructed from '$PWD' and the directory name supplied as an
argument does not refer to an existing directory, 'cd' will fail
instead of falling back to physical mode.
- 51. When the 'cd' builtin cannot change a directory because the length
+ 52. When the 'cd' builtin cannot change a directory because the length
of the pathname constructed from '$PWD' and the directory name
supplied as an argument exceeds 'PATH_MAX' when all symbolic links
are expanded, 'cd' will fail instead of attempting to use only the
supplied directory name.
- 52. The 'pwd' builtin verifies that the value it prints is the same as
+ 53. The 'pwd' builtin verifies that the value it prints is the same as
the current directory, even if it is not asked to check the file
system with the '-P' option.
- 53. When listing the history, the 'fc' builtin does not include an
+ 54. When listing the history, the 'fc' builtin does not include an
indication of whether or not a history entry has been modified.
- 54. The default editor used by 'fc' is 'ed'.
+ 55. The default editor used by 'fc' is 'ed'.
+
+ 56. If there are too many arguments supplied to 'fc -s', 'fc' prints
+ an error message and returns failure.
- 55. The 'type' and 'command' builtins will not report a non-executable
+ 57. The 'type' and 'command' builtins will not report a non-executable
file as having been found, though the shell will attempt to execute
such a file if it is the only so-named file found in '$PATH'.
- 56. The 'vi' editing mode will invoke the 'vi' editor directly when
+ 58. The 'vi' editing mode will invoke the 'vi' editor directly when
the 'v' command is run, instead of checking '$VISUAL' and
'$EDITOR'.
- 57. When the 'xpg_echo' option is enabled, Bash does not attempt to
+ 59. When the 'xpg_echo' option is enabled, Bash does not attempt to
interpret any arguments to 'echo' as options. Each argument is
displayed, after escape characters are converted.
- 58. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
+ 60. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
and '-f' options.
- 59. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
+ 61. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
interrupt the 'wait' builtin and cause it to return immediately.
The trap command is run once for each child that exits.
- 60. The 'read' builtin may be interrupted by a signal for which a trap
+ 62. The 'read' builtin may be interrupted by a signal for which a trap
has been set. If Bash receives a trapped signal while executing
'read', the trap handler executes and 'read' returns an exit status
greater than 128.
- 61. The 'printf' builtin uses 'double' (via 'strtod') to convert
+ 63. The 'printf' builtin uses 'double' (via 'strtod') to convert
arguments corresponding to floating point conversion specifiers,
instead of 'long double' if it's available. The 'L' length
modifier forces 'printf' to use 'long double' if it's available.
- 62. Bash removes an exited background process's status from the list
+ 64. Bash removes an exited background process's status from the list
of such statuses after the 'wait' builtin is used to obtain it.
- 63. A double quote character ('"') is treated specially when it
+ 65. A double quote character ('"') is treated specially when it
appears in a backquoted command substitution in the body of a
here-document that undergoes expansion. That means, for example,
that a backslash preceding a double quote character will escape it
(line 69)
* pwd: Bourne Shell Builtins.
(line 212)
-* read: Bash Builtins. (line 492)
-* readarray: Bash Builtins. (line 589)
+* read: Bash Builtins. (line 503)
+* readarray: Bash Builtins. (line 600)
* readonly: Bourne Shell Builtins.
(line 222)
* return: Bourne Shell Builtins.
* shift: Bourne Shell Builtins.
(line 262)
* shopt: The Shopt Builtin. (line 9)
-* source: Bash Builtins. (line 598)
+* source: Bash Builtins. (line 609)
* suspend: Job Control Builtins.
(line 116)
* test: Bourne Shell Builtins.
(line 360)
* trap: Bourne Shell Builtins.
(line 366)
-* type: Bash Builtins. (line 603)
-* typeset: Bash Builtins. (line 641)
-* ulimit: Bash Builtins. (line 647)
+* type: Bash Builtins. (line 614)
+* typeset: Bash Builtins. (line 652)
+* ulimit: Bash Builtins. (line 658)
* umask: Bourne Shell Builtins.
(line 428)
-* unalias: Bash Builtins. (line 753)
+* unalias: Bash Builtins. (line 764)
* unset: Bourne Shell Builtins.
(line 446)
* wait: Job Control Builtins.
Node: Shell Builtin Commands\7f137627
Node: Bourne Shell Builtins\7f139665
Node: Bash Builtins\7f161863
-Node: Modifying Shell Behavior\7f193254
-Node: The Set Builtin\7f193599
-Node: The Shopt Builtin\7f204197
-Node: Special Builtins\7f220109
-Node: Shell Variables\7f221088
-Node: Bourne Shell Variables\7f221525
-Node: Bash Variables\7f223629
-Node: Bash Features\7f256444
-Node: Invoking Bash\7f257457
-Node: Bash Startup Files\7f263470
-Node: Interactive Shells\7f268601
-Node: What is an Interactive Shell?\7f269012
-Node: Is this Shell Interactive?\7f269661
-Node: Interactive Shell Behavior\7f270476
-Node: Bash Conditional Expressions\7f274105
-Node: Shell Arithmetic\7f278747
-Node: Aliases\7f281691
-Node: Arrays\7f284304
-Node: The Directory Stack\7f290695
-Node: Directory Stack Builtins\7f291479
-Node: Controlling the Prompt\7f295739
-Node: The Restricted Shell\7f298704
-Node: Bash POSIX Mode\7f301314
-Node: Shell Compatibility Mode\7f313876
-Node: Job Control\7f322443
-Node: Job Control Basics\7f322903
-Node: Job Control Builtins\7f327905
-Node: Job Control Variables\7f333700
-Node: Command Line Editing\7f334856
-Node: Introduction and Notation\7f336527
-Node: Readline Interaction\7f338150
-Node: Readline Bare Essentials\7f339341
-Node: Readline Movement Commands\7f341130
-Node: Readline Killing Commands\7f342090
-Node: Readline Arguments\7f344011
-Node: Searching\7f345055
-Node: Readline Init File\7f347241
-Node: Readline Init File Syntax\7f348502
-Node: Conditional Init Constructs\7f372088
-Node: Sample Init File\7f376284
-Node: Bindable Readline Commands\7f379408
-Node: Commands For Moving\7f380612
-Node: Commands For History\7f382663
-Node: Commands For Text\7f387657
-Node: Commands For Killing\7f391306
-Node: Numeric Arguments\7f394339
-Node: Commands For Completion\7f395478
-Node: Keyboard Macros\7f399669
-Node: Miscellaneous Commands\7f400357
-Node: Readline vi Mode\7f406302
-Node: Programmable Completion\7f407209
-Node: Programmable Completion Builtins\7f414989
-Node: A Programmable Completion Example\7f425741
-Node: Using History Interactively\7f430989
-Node: Bash History Facilities\7f431673
-Node: Bash History Builtins\7f434678
-Node: History Interaction\7f439702
-Node: Event Designators\7f443322
-Node: Word Designators\7f444676
-Node: Modifiers\7f446436
-Node: Installing Bash\7f448244
-Node: Basic Installation\7f449381
-Node: Compilers and Options\7f453103
-Node: Compiling For Multiple Architectures\7f453844
-Node: Installation Names\7f455536
-Node: Specifying the System Type\7f457645
-Node: Sharing Defaults\7f458362
-Node: Operation Controls\7f459035
-Node: Optional Features\7f459993
-Node: Reporting Bugs\7f471212
-Node: Major Differences From The Bourne Shell\7f472556
-Node: GNU Free Documentation License\7f489405
-Node: Indexes\7f514582
-Node: Builtin Index\7f515036
-Node: Reserved Word Index\7f521863
-Node: Variable Index\7f524311
-Node: Function Index\7f541085
-Node: Concept Index\7f554869
+Node: Modifying Shell Behavior\7f193831
+Node: The Set Builtin\7f194176
+Node: The Shopt Builtin\7f204774
+Node: Special Builtins\7f220686
+Node: Shell Variables\7f221665
+Node: Bourne Shell Variables\7f222102
+Node: Bash Variables\7f224206
+Node: Bash Features\7f257021
+Node: Invoking Bash\7f258034
+Node: Bash Startup Files\7f264047
+Node: Interactive Shells\7f269178
+Node: What is an Interactive Shell?\7f269589
+Node: Is this Shell Interactive?\7f270238
+Node: Interactive Shell Behavior\7f271053
+Node: Bash Conditional Expressions\7f274682
+Node: Shell Arithmetic\7f279324
+Node: Aliases\7f282268
+Node: Arrays\7f284881
+Node: The Directory Stack\7f291272
+Node: Directory Stack Builtins\7f292056
+Node: Controlling the Prompt\7f296316
+Node: The Restricted Shell\7f299281
+Node: Bash POSIX Mode\7f301891
+Node: Shell Compatibility Mode\7f314757
+Node: Job Control\7f323324
+Node: Job Control Basics\7f323784
+Node: Job Control Builtins\7f328786
+Node: Job Control Variables\7f334581
+Node: Command Line Editing\7f335737
+Node: Introduction and Notation\7f337408
+Node: Readline Interaction\7f339031
+Node: Readline Bare Essentials\7f340222
+Node: Readline Movement Commands\7f342011
+Node: Readline Killing Commands\7f342971
+Node: Readline Arguments\7f344892
+Node: Searching\7f345936
+Node: Readline Init File\7f348122
+Node: Readline Init File Syntax\7f349383
+Node: Conditional Init Constructs\7f372969
+Node: Sample Init File\7f377165
+Node: Bindable Readline Commands\7f380289
+Node: Commands For Moving\7f381493
+Node: Commands For History\7f383544
+Node: Commands For Text\7f388538
+Node: Commands For Killing\7f392187
+Node: Numeric Arguments\7f395220
+Node: Commands For Completion\7f396359
+Node: Keyboard Macros\7f400550
+Node: Miscellaneous Commands\7f401238
+Node: Readline vi Mode\7f407183
+Node: Programmable Completion\7f408090
+Node: Programmable Completion Builtins\7f415870
+Node: A Programmable Completion Example\7f426622
+Node: Using History Interactively\7f431870
+Node: Bash History Facilities\7f432554
+Node: Bash History Builtins\7f435559
+Node: History Interaction\7f440583
+Node: Event Designators\7f444203
+Node: Word Designators\7f445557
+Node: Modifiers\7f447317
+Node: Installing Bash\7f449125
+Node: Basic Installation\7f450262
+Node: Compilers and Options\7f453984
+Node: Compiling For Multiple Architectures\7f454725
+Node: Installation Names\7f456417
+Node: Specifying the System Type\7f458526
+Node: Sharing Defaults\7f459243
+Node: Operation Controls\7f459916
+Node: Optional Features\7f460874
+Node: Reporting Bugs\7f472093
+Node: Major Differences From The Bourne Shell\7f473437
+Node: GNU Free Documentation License\7f490286
+Node: Indexes\7f515463
+Node: Builtin Index\7f515917
+Node: Reserved Word Index\7f522744
+Node: Variable Index\7f525192
+Node: Function Index\7f541966
+Node: Concept Index\7f555750
\1f
End Tag Table
%\b%b\bb causes p\bpr\bri\bin\bnt\btf\bf to expand backslash escape sequences in the
corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in the same way as e\bec\bch\bho\bo -\b-e\be.
%\b%q\bq causes p\bpr\bri\bin\bnt\btf\bf to output the corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in a
- format that can be reused as shell input.
- %\b%Q\bQ like %\b%q\bq, but applies any supplied precision to the _\ba_\br_\bg_\bu_\b-
+ format that can be reused as shell input. %\b%q\bq and %\b%Q\bQ use
+ the $\b$'\b''\b' quoting style if any characters in the argument
+ string require it, and backslash quoting otherwise. If
+ the format string uses the _\bp_\br_\bi_\bn_\bt_\bf alternate form, these
+ two formats quote the argument string using single
+ quotes.
+ %\b%Q\bQ like %\b%q\bq, but applies any supplied precision to the _\ba_\br_\bg_\bu_\b-
_\bm_\be_\bn_\bt before quoting it.
%\b%(\b(_\bd_\ba_\bt_\be_\bf_\bm_\bt)\b)T\bT
- causes p\bpr\bri\bin\bnt\btf\bf to output the date-time string resulting
- from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
+ causes p\bpr\bri\bin\bnt\btf\bf to output the date-time string resulting
+ from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
The corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt is an integer representing the
- number of seconds since the epoch. Two special argument
- values may be used: -1 represents the current time, and
- -2 represents the time the shell was invoked. If no ar-
+ number of seconds since the epoch. Two special argument
+ values may be used: -1 represents the current time, and
+ -2 represents the time the shell was invoked. If no ar-
gument is specified, conversion behaves as if -1 had been
- given. This is an exception to the usual p\bpr\bri\bin\bnt\btf\bf behav-
+ given. This is an exception to the usual p\bpr\bri\bin\bnt\btf\bf behav-
ior.
- The %b, %q, and %T directives all use the field width and preci-
- sion arguments from the format specification and write that many
- bytes from (or use that wide a field for) the expanded argument,
- which usually contains more characters than the original.
+ The %b, %q, and %T format specifiers all use the field width and
+ precision arguments from the format specification and write that
+ many bytes from (or use that wide a field for) the expanded ar-
+ gument, which usually contains more characters than the origi-
+ nal.
The %n format specifier accepts a corresponding argument that is
treated as a shell variable name.
- Arguments to non-string format specifiers are treated as C con-
+ The %s and %c format specifiers accept an l (long) modifier,
+ which forces them to convert the argument string to a wide-char-
+ acter string and apply any supplied field width and precision in
+ terms of characters, not bytes.
+
+ Arguments to non-string format specifiers are treated as C con-
stants, except that a leading plus or minus sign is allowed, and
- if the leading character is a single or double quote, the value
+ if the leading character is a single or double quote, the value
is the ASCII value of the following character.
- The _\bf_\bo_\br_\bm_\ba_\bt is reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
+ The _\bf_\bo_\br_\bm_\ba_\bt is reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
_\bm_\be_\bn_\bt_\bs. If the _\bf_\bo_\br_\bm_\ba_\bt requires more _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs than are supplied,
- the extra format specifications behave as if a zero value or
- null string, as appropriate, had been supplied. The return
- value is zero on success, non-zero if an invalid option is sup-
+ 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 if an invalid option is sup-
plied or a write or assignment error occurs.
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
- directory. With no arguments, p\bpu\bus\bsh\bhd\bd exchanges the top two ele-
- ments of the directory stack. Arguments, if supplied, have the
+ 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, p\bpu\bus\bsh\bhd\bd exchanges the top two ele-
+ ments of the directory stack. Arguments, if supplied, have the
following meanings:
- -\b-n\bn Suppresses the normal change of directory when rotating
- or adding directories to the stack, so that only the
+ -\b-n\bn Suppresses the normal change of directory when rotating
+ or 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
After the stack has been modified, if the -\b-n\bn option was not sup-
- plied, p\bpu\bus\bsh\bhd\bd uses the c\bcd\bd builtin to change to the directory at
+ plied, p\bpu\bus\bsh\bhd\bd uses the c\bcd\bd builtin to change to the directory at
the top of the stack. If the c\bcd\bd fails, p\bpu\bus\bsh\bhd\bd returns a non-zero
value.
- Otherwise, if no arguments are supplied, p\bpu\bus\bsh\bhd\bd returns 0 unless
- the directory stack is empty. When rotating the directory
- stack, p\bpu\bus\bsh\bhd\bd returns 0 unless the directory stack is empty or a
+ Otherwise, if no arguments are supplied, p\bpu\bus\bsh\bhd\bd returns 0 unless
+ the directory stack is empty. When rotating the directory
+ stack, p\bpu\bus\bsh\bhd\bd returns 0 unless the directory stack is empty or a
non-existent directory stack element is specified.
- If the p\bpu\bus\bsh\bhd\bd command is successful, bash runs d\bdi\bir\brs\bs to show the
+ If the p\bpu\bus\bsh\bhd\bd command is successful, bash runs d\bdi\bir\brs\bs to show the
final contents of the directory stack.
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
+ 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 in-
valid 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-i\bi _\bt_\be_\bx_\bt] [-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs] [-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs] [-\b-p\bp
_\bp_\br_\bo_\bm_\bp_\bt] [-\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt] [-\b-u\bu _\bf_\bd] [_\bn_\ba_\bm_\be ...]
- One line is read from the standard input, or from the file de-
+ One line is read from the standard input, or from the file de-
scriptor _\bf_\bd supplied as an argument to the -\b-u\bu option, split into
- words as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the
+ words as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the
first word is assigned to the first _\bn_\ba_\bm_\be, the second word to the
second _\bn_\ba_\bm_\be, and so on. If there are more words than names, the
remaining words and their intervening delimiters are assigned to
- the last _\bn_\ba_\bm_\be. If there are fewer words read from the input
- stream than names, the remaining names are assigned empty val-
- ues. The characters in I\bIF\bFS\bS are used to split the line into
- words using the same rules the shell uses for expansion (de-
+ the last _\bn_\ba_\bm_\be. If there are fewer words read from the input
+ stream than names, the remaining names are assigned empty val-
+ ues. The characters in I\bIF\bFS\bS are used to split the line into
+ words using the same rules the shell uses for expansion (de-
scribed in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg). The backslash charac-
- ter (\\b\) may be used to remove any special meaning for the next
+ ter (\\b\) may be used to remove any special meaning for the next
character read and for line continuation. Options, if supplied,
have the following meanings:
-\b-a\ba _\ba_\bn_\ba_\bm_\be
The words are assigned to sequential indices of the array
variable _\ba_\bn_\ba_\bm_\be, starting at 0. _\ba_\bn_\ba_\bm_\be is unset before any
- new values are assigned. Other _\bn_\ba_\bm_\be arguments are ig-
+ new values are assigned. Other _\bn_\ba_\bm_\be arguments are ig-
nored.
-\b-d\bd _\bd_\be_\bl_\bi_\bm
The first character of _\bd_\be_\bl_\bi_\bm is used to terminate the in-
- put line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
- string, r\bre\bea\bad\bd will terminate a line when it reads a NUL
+ put line, rather than newline. If _\bd_\be_\bl_\bi_\bm is the empty
+ string, r\bre\bea\bad\bd will terminate a line when it reads a NUL
character.
-\b-e\be If the standard input is coming from a terminal, r\bre\bea\bad\bdl\bli\bin\bne\be
- (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) is used to obtain the line.
- Readline uses the current (or default, if line editing
- was not previously active) editing settings, but uses
+ (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) is used to obtain the line.
+ Readline uses the current (or default, if line editing
+ was not previously active) editing settings, but uses
readline's default filename completion.
-\b-i\bi _\bt_\be_\bx_\bt
- If r\bre\bea\bad\bdl\bli\bin\bne\be is being used to read the line, _\bt_\be_\bx_\bt is
+ If r\bre\bea\bad\bdl\bli\bin\bne\be is being used to read the line, _\bt_\be_\bx_\bt is
placed into the editing buffer before editing begins.
-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs
- r\bre\bea\bad\bd returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
+ r\bre\bea\bad\bd returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
waiting for a complete line of input, but honors a delim-
- iter if fewer than _\bn_\bc_\bh_\ba_\br_\bs characters are read before the
+ iter if fewer than _\bn_\bc_\bh_\ba_\br_\bs characters are read before the
delimiter.
-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs
- r\bre\bea\bad\bd returns after reading exactly _\bn_\bc_\bh_\ba_\br_\bs characters
- rather than waiting for a complete line of input, unless
- EOF is encountered or r\bre\bea\bad\bd times out. Delimiter charac-
- ters encountered in the input are not treated specially
- and do not cause r\bre\bea\bad\bd to return until _\bn_\bc_\bh_\ba_\br_\bs characters
- are read. The result is not split on the characters in
- I\bIF\bFS\bS; the intent is that the variable is assigned exactly
+ r\bre\bea\bad\bd returns after reading exactly _\bn_\bc_\bh_\ba_\br_\bs characters
+ rather than waiting for a complete line of input, unless
+ EOF is encountered or r\bre\bea\bad\bd times out. Delimiter charac-
+ ters encountered in the input are not treated specially
+ and do not cause r\bre\bea\bad\bd to return until _\bn_\bc_\bh_\ba_\br_\bs characters
+ are read. The result is not split on the characters in
+ I\bIF\bFS\bS; the intent is that the variable is assigned exactly
the characters read (with the exception of backslash; see
the -\b-r\br option below).
-\b-p\bp _\bp_\br_\bo_\bm_\bp_\bt
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 then be used as a
+ slash is considered to be part of the line. In particu-
+ lar, a backslash-newline pair may not then 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 (or a specified number of characters) is
- not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a deci-
- mal number with a fractional portion following the deci-
- mal point. This option is only effective if r\bre\bea\bad\bd is
- reading input from a terminal, pipe, or other special
- file; it has no effect when reading from regular files.
+ Cause r\bre\bea\bad\bd to time out and return failure if a complete
+ line of input (or a specified number of characters) is
+ not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds. _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a deci-
+ mal number with a fractional portion following the deci-
+ mal point. This option is only effective if r\bre\bea\bad\bd is
+ reading input from a terminal, pipe, or other special
+ file; it has no effect when reading from regular files.
If r\bre\bea\bad\bd times out, r\bre\bea\bad\bd saves any partial input read into
- the specified variable _\bn_\ba_\bm_\be. If _\bt_\bi_\bm_\be_\bo_\bu_\bt is 0, r\bre\bea\bad\bd re-
- turns immediately, without trying to read any data. The
- exit status is 0 if input is available on the specified
- file descriptor, or the read will return EOF, non-zero
- otherwise. The exit status is greater than 128 if the
+ the specified variable _\bn_\ba_\bm_\be. If _\bt_\bi_\bm_\be_\bo_\bu_\bt is 0, r\bre\bea\bad\bd re-
+ turns immediately, without trying to read any data. The
+ exit status is 0 if input is available on the specified
+ file descriptor, or the read will return EOF, non-zero
+ otherwise. The exit status is greater than 128 if the
timeout is exceeded.
-\b-u\bu _\bf_\bd Read input from file descriptor _\bf_\bd.
- If no _\bn_\ba_\bm_\be_\bs are supplied, the line read, without the ending de-
- limiter but otherwise unmodified, is assigned to the variable
- R\bRE\bEP\bPL\bLY\bY. The exit status is zero, unless end-of-file is encoun-
- tered, r\bre\bea\bad\bd times out (in which case the status is greater than
- 128), a variable assignment error (such as assigning to a read-
+ If no _\bn_\ba_\bm_\be_\bs are supplied, the line read, without the ending de-
+ limiter but otherwise unmodified, is assigned to the variable
+ R\bRE\bEP\bPL\bLY\bY. The exit status is zero, unless end-of-file is encoun-
+ tered, r\bre\bea\bad\bd times out (in which case the status is greater than
+ 128), a variable assignment error (such as assigning to a read-
only variable) occurs, or an invalid file descriptor is supplied
as the argument to -\b-u\bu.
r\bre\bea\bad\bdo\bon\bnl\bly\by [-\b-a\baA\bAf\bf] [-\b-p\bp] [_\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
- marked. The -\b-a\ba option restricts the variables to indexed ar-
- rays; the -\b-A\bA option restricts the variables to associative ar-
+ 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 indexed ar-
+ rays; the -\b-A\bA option restricts the variables to associative ar-
rays. If both options are supplied, -\b-A\bA takes precedence. If no
- _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
+ _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
list of all readonly names is printed. The other options may be
- used to restrict the output to a subset of the set of readonly
- names. The -\b-p\bp option causes output to be displayed in a format
- that may be reused as input. If a variable name is followed by
- =_\bw_\bo_\br_\bd, the value of the variable is set to _\bw_\bo_\br_\bd. The return
- status is 0 unless an invalid option is encountered, one of the
+ used to restrict the output to a subset of the set of readonly
+ names. The -\b-p\bp option causes output to be displayed in a format
+ that may be reused as input. If a variable name is followed by
+ =_\bw_\bo_\br_\bd, the value of the variable 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 function.
r\bre\bet\btu\bur\brn\bn [_\bn]
- Causes a function to stop executing and return the value speci-
- fied by _\bn to its caller. If _\bn is omitted, the return status is
- that of the last command executed in the function body. If r\bre\be-\b-
+ Causes a function to stop executing and return the value speci-
+ fied by _\bn to its caller. If _\bn is omitted, the return status is
+ that of the last command executed in the function body. If r\bre\be-\b-
t\btu\bur\brn\bn is executed by a trap handler, the last command used to de-
- termine the status is the last command executed before the trap
- handler. If r\bre\bet\btu\bur\brn\bn is executed during a D\bDE\bEB\bBU\bUG\bG trap, the last
- command used to determine the status is the last command exe-
- cuted by the trap handler before r\bre\bet\btu\bur\brn\bn was invoked. If r\bre\bet\btu\bur\brn\bn
- is 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
+ termine the status is the last command executed before the trap
+ handler. If r\bre\bet\btu\bur\brn\bn is executed during a D\bDE\bEB\bBU\bUG\bG trap, the last
+ command used to determine the status is the last command exe-
+ cuted by the trap handler before r\bre\bet\btu\bur\brn\bn was invoked. If r\bre\bet\btu\bur\brn\bn
+ is 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 _\bn is supplied, the return value is its least signif-
- icant 8 bits. The return status is non-zero if r\bre\bet\btu\bur\brn\bn is sup-
- plied a non-numeric argument, or is used outside a function and
- not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be. Any command
+ icant 8 bits. The return status is non-zero if r\bre\bet\btu\bur\brn\bn is sup-
+ plied a non-numeric argument, or is used outside a function and
+ not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be. Any command
associated with the R\bRE\bET\bTU\bUR\bRN\bN trap is executed before execution re-
sumes after the function or script.
s\bse\bet\bt [-\b-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_\b-_\bn_\ba_\bm_\be] [-\b--\b-] [-\b-] [_\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_\b-_\bn_\ba_\bm_\be] [-\b--\b-] [-\b-] [_\ba_\br_\bg ...]
- Without options, display the name and value of each shell vari-
- able in a format that can be reused as input for setting or re-
+ Without options, display the name and value of each shell vari-
+ able in a format that can be reused as input for setting or re-
setting the currently-set variables. Read-only variables cannot
- be reset. In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed. The
- output is sorted according to the current locale. When options
- are specified, they set or unset shell attributes. Any argu-
- ments remaining after option processing are treated as values
+ be reset. In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed. The
+ output is sorted according to the current locale. When options
+ are specified, they set or unset shell attributes. Any argu-
+ ments remaining after option processing are treated as values
for the positional parameters and are assigned, in order, to $\b$1\b1,
- $\b$2\b2, .\b..\b..\b. $\b$_\bn. Options, if specified, have the following mean-
+ $\b$2\b2, .\b..\b..\b. $\b$_\bn. Options, if specified, have the following mean-
ings:
-\b-a\ba Each variable or function that is created or modified is
- given the export attribute and marked for export to the
+ given the export attribute and marked for export to the
environment of subsequent commands.
- -\b-b\bb Report the status of terminated background jobs immedi-
+ -\b-b\bb Report the status of terminated background jobs immedi-
ately, rather than before the next primary prompt. This
is effective only when job control is enabled.
- -\b-e\be Exit immediately if a _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be (which may consist of a
- single _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd), a _\bl_\bi_\bs_\bt, or a _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd _\bc_\bo_\bm_\bm_\ba_\bn_\bd
- (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh_\b(_\b1_\b)), exits with a non-zero
- status. The shell does not exit if the command that
- fails is part of the command list immediately following
+ -\b-e\be Exit immediately if a _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be (which may consist of a
+ single _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd), a _\bl_\bi_\bs_\bt, or a _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd _\bc_\bo_\bm_\bm_\ba_\bn_\bd
+ (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh_\b(_\b1_\b)), exits with a non-zero
+ status. The shell does not exit if the command that
+ fails is part of the command list immediately following
a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test following the
- i\bif\bf or e\bel\bli\bif\bf reserved words, part of any command executed
- in a &\b&&\b& or |\b||\b| list except the command following the fi-
+ i\bif\bf or e\bel\bli\bif\bf reserved words, part of any command executed
+ in a &\b&&\b& or |\b||\b| list except the command following the fi-
nal &\b&&\b& or |\b||\b|, any command in a pipeline but the last, or
- if the command's return value is being inverted with !\b!.
- If a compound command other than a subshell returns a
- non-zero status because a command failed while -\b-e\be was
- being ignored, the shell does not exit. A trap on E\bER\bRR\bR,
+ if the command's return value is being inverted with !\b!.
+ If a compound command other than a subshell returns a
+ non-zero status because a command failed while -\b-e\be was
+ being ignored, the shell does not exit. A trap on E\bER\bRR\bR,
if set, is executed before the shell exits. This option
applies to the shell environment and each subshell envi-
ronment separately (see C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bNM\bME\bEN\bNT\bT in
_\bb_\ba_\bs_\bh_\b(_\b1_\b)), and may cause subshells to exit before execut-
ing all the commands in the subshell.
- If a compound command or shell function executes in a
- context where -\b-e\be is being ignored, none of the commands
- executed within the compound command or function body
- will be affected by the -\b-e\be setting, even if -\b-e\be is set
- and a command returns a failure status. If a compound
- command or shell function sets -\b-e\be while executing in a
- context where -\b-e\be is ignored, that setting will not have
- any effect until the compound command or the command
+ If a compound command or shell function executes in a
+ context where -\b-e\be is being ignored, none of the commands
+ executed within the compound command or function body
+ will be affected by the -\b-e\be setting, even if -\b-e\be is set
+ and a command returns a failure status. If a compound
+ command or shell function sets -\b-e\be while executing in a
+ context where -\b-e\be is ignored, that setting will not have
+ any effect until the compound command or the command
containing the function call completes.
-\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 in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). All processes
- run in a separate process group. When a background job
- completes, the shell prints a line containing its exit
+ -\b-m\bm Monitor mode. Job control is enabled. This option is
+ on by default for interactive shells on systems that
+ support it (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). All processes
+ run in a separate process group. When a background job
+ completes, the shell prints a line containing its exit
status.
-\b-n\bn Read commands but do not execute them. This may be used
- to check a shell script for syntax errors. This is ig-
+ to check a shell script for syntax errors. This is ig-
nored by interactive shells.
-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
The _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be can be one of the following:
Same as -\b-a\ba.
b\bbr\bra\bac\bce\bee\bex\bxp\bpa\ban\bnd\bd
Same as -\b-B\bB.
- e\bem\bma\bac\bcs\bs Use an emacs-style command line editing inter-
+ e\bem\bma\bac\bcs\bs Use an emacs-style command line editing inter-
face. This is enabled by default when the shell
is interactive, unless the shell is started with
- the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option. This also affects the
+ the -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option. This also affects the
editing interface used for r\bre\bea\bad\bd -\b-e\be.
e\ber\brr\bre\bex\bxi\bit\bt Same as -\b-e\be.
e\ber\brr\brt\btr\bra\bac\bce\be
h\bha\bas\bsh\bha\bal\bll\bl Same as -\b-h\bh.
h\bhi\bis\bst\bte\bex\bxp\bpa\ban\bnd\bd
Same as -\b-H\bH.
- h\bhi\bis\bst\bto\bor\bry\by Enable command history, as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b)
- under H\bHI\bIS\bST\bTO\bOR\bRY\bY. This option is on by default in
+ h\bhi\bis\bst\bto\bor\bry\by Enable command history, as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b)
+ under H\bHI\bIS\bST\bTO\bOR\bRY\bY. This option is on by default in
interactive shells.
i\big\bgn\bno\bor\bre\bee\beo\bof\bf
- The effect is as if the shell command ``IG-
- NOREEOF=10'' had been executed (see S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bi-\b-
+ The effect is as if the shell command ``IG-
+ NOREEOF=10'' had been executed (see S\bSh\bhe\bel\bll\bl V\bVa\bar\bri\bi-\b-
a\bab\bbl\ble\bes\bs in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
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
- match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be). See S\bSE\bEE\bE A\bAL\bLS\bSO\bO
- in _\bb_\ba_\bs_\bh_\b(_\b1_\b) for a reference to a document that
+ p\bpo\bos\bsi\bix\bx Change the behavior of b\bba\bas\bsh\bh where the default
+ operation differs from the POSIX standard to
+ match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be). See S\bSE\bEE\bE A\bAL\bLS\bSO\bO
+ in _\bb_\ba_\bs_\bh_\b(_\b1_\b) for a reference to a document that
details how posix mode affects bash's behavior.
p\bpr\bri\biv\bvi\bil\ble\beg\bge\bed\bd
Same as -\b-p\bp.
v\bve\ber\brb\bbo\bos\bse\be Same as -\b-v\bv.
- v\bvi\bi Use a vi-style command line editing interface.
+ v\bvi\bi Use a vi-style command line editing interface.
This also affects the editing interface used for
r\bre\bea\bad\bd -\b-e\be.
x\bxt\btr\bra\bac\bce\be Same as -\b-x\bx.
If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, 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,
- B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
- pear in the environment, are ignored. If the shell is
- started with the effective user (group) id not equal to
- the real user (group) id, and the -\b-p\bp option is not sup-
+ -\b-p\bp Turn on _\bp_\br_\bi_\bv_\bi_\bl_\be_\bg_\be_\bd mode. In this mode, the $\b$E\bEN\bNV\bV and
+ $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV files are not processed, shell functions are
+ not inherited from the environment, and the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
+ B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH, and G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE variables, if they ap-
+ pear in the environment, are ignored. If the shell is
+ started with the effective user (group) id not equal to
+ the real user (group) id, and the -\b-p\bp option is not sup-
plied, these actions are taken and the effective user id
- is set to the real user id. If the -\b-p\bp option is sup-
- plied at startup, the effective user id is not reset.
- Turning this option off causes the effective user and
+ is set to the real user id. If the -\b-p\bp option is sup-
+ plied at startup, the effective user id is not reset.
+ Turning this option off causes the effective user and
group ids to be set to the real user and group ids.
-\b-r\br Enable restricted shell mode. This option cannot be un-
set once it has been set.
-\b-t\bt Exit after reading and executing one command.
-\b-u\bu Treat unset variables and parameters other than the spe-
- cial parameters "@" and "*", or array variables sub-
- scripted with "@" or "*", as an error when performing
- parameter expansion. If expansion is attempted on an
- unset variable or parameter, the shell prints an error
- message, and, if not interactive, exits with a non-zero
+ cial parameters "@" and "*", or array variables sub-
+ scripted with "@" or "*", as an error when performing
+ parameter expansion. If expansion is attempted on an
+ unset variable or parameter, the shell prints an error
+ message, and, if not interactive, exits with a non-zero
status.
-\b-v\bv Print shell input lines as they are read.
- -\b-x\bx After expanding each _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, f\bfo\bor\br command, c\bca\bas\bse\be
+ -\b-x\bx After expanding each _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, f\bfo\bor\br command, c\bca\bas\bse\be
command, s\bse\bel\ble\bec\bct\bt command, or arithmetic f\bfo\bor\br command, dis-
- play the expanded value of P\bPS\bS4\b4, followed by the command
- and its expanded arguments or associated word list, to
+ play the expanded value of P\bPS\bS4\b4, followed by the command
+ and its expanded arguments or associated word list, to
standard error.
- -\b-B\bB The shell performs brace expansion (see B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
+ -\b-B\bB The shell performs brace expansion (see B\bBr\bra\bac\bce\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). 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 resolve symbolic links when
- executing commands such as c\bcd\bd that change the current
+ -\b-P\bP If set, the shell does not resolve symbolic links when
+ executing commands such as c\bcd\bd that change the current
working directory. It uses the physical directory
structure instead. By default, b\bba\bas\bsh\bh follows the logical
- chain of directories when performing commands which
+ chain of directories when performing commands which
change the current directory.
- -\b-T\bT If set, any traps on D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN are inherited by
+ -\b-T\bT If set, any traps on D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN are inherited by
shell functions, command substitutions, and commands ex-
- ecuted in a subshell environment. The D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN
+ ecuted in a subshell environment. The D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN
traps are normally not inherited in such cases.
- -\b--\b- If no arguments follow this option, then the positional
+ -\b--\b- If no arguments follow this option, then the positional
parameters are unset. Otherwise, the positional parame-
- ters are set to the _\ba_\br_\bgs, even if some of them begin
+ ters are set to the _\ba_\br_\bgs, even if some of them begin
with a -\b-.
- -\b- Signal the end of options, cause all remaining _\ba_\br_\bgs to
+ -\b- Signal the end of options, cause all remaining _\ba_\br_\bgs to
be assigned to the positional parameters. The -\b-x\bx and -\b-v\bv
options are turned off. If there are no _\ba_\br_\bgs, the posi-
tional parameters remain unchanged.
- The options are off by default unless otherwise noted. Using +
- rather than - causes these options to be turned off. The op-
+ The options are off by default unless otherwise noted. Using +
+ rather than - causes these options to be turned off. The op-
tions can also be specified as arguments to an invocation of the
- shell. The current set of options may be found in $\b$-\b-. The re-
- turn status is always true unless an invalid option is encoun-
+ shell. The current set of options may be found in $\b$-\b-. The re-
+ turn status is always true unless an invalid option is encoun-
tered.
s\bsh\bhi\bif\bft\bt [_\bn]
- The positional parameters from _\bn+1 ... are renamed to $\b$1\b1 .\b..\b..\b..\b.
- Parameters represented by the numbers $\b$#\b# down to $\b$#\b#-_\bn+1 are un-
- set. _\bn must be a non-negative number less than or equal to $\b$#\b#.
- If _\bn is 0, no parameters are changed. If _\bn is not given, it is
+ The positional parameters from _\bn+1 ... are renamed to $\b$1\b1 .\b..\b..\b..\b.
+ Parameters represented by the numbers $\b$#\b# down to $\b$#\b#-_\bn+1 are un-
+ set. _\bn must be a non-negative number less than or equal to $\b$#\b#.
+ If _\bn is 0, no parameters are changed. If _\bn is not given, it is
assumed to be 1. If _\bn is greater than $\b$#\b#, the positional param-
- eters are not changed. The return status is greater than zero
+ eters are not changed. The return status is greater than zero
if _\bn is greater than $\b$#\b# or less than zero; otherwise 0.
s\bsh\bho\bop\bpt\bt [-\b-p\bpq\bqs\bsu\bu] [-\b-o\bo] [_\bo_\bp_\bt_\bn_\ba_\bm_\be ...]
- Toggle the values of settings controlling optional shell behav-
- ior. The settings can be either those listed below, or, if the
+ Toggle the values of settings controlling optional shell behav-
+ ior. The settings can be either those listed below, or, if the
-\b-o\bo option is used, those available with the -\b-o\bo option to the s\bse\bet\bt
builtin command. With no options, or with the -\b-p\bp option, a list
- of all settable options is displayed, with an indication of
+ of all settable options is displayed, with an indication of
whether or not each is set; if _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are supplied, the output
- is restricted to those options. The -\b-p\bp option causes output to
- be displayed in a form that may be reused as input. Other op-
+ is restricted to those options. The -\b-p\bp option causes output to
+ be displayed in a form that may be reused as input. Other op-
tions have the following meanings:
-\b-s\bs Enable (set) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
-\b-u\bu Disable (unset) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
- -\b-q\bq Suppresses normal output (quiet mode); the return status
+ -\b-q\bq Suppresses normal output (quiet mode); the return status
indicates whether the _\bo_\bp_\bt_\bn_\ba_\bm_\be is set or unset. If multi-
- ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return sta-
- tus is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
+ ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return sta-
+ tus is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
wise.
- -\b-o\bo Restricts the values of _\bo_\bp_\bt_\bn_\ba_\bm_\be to be those defined for
+ -\b-o\bo Restricts the values of _\bo_\bp_\bt_\bn_\ba_\bm_\be to be those defined for
the -\b-o\bo option to the s\bse\bet\bt builtin.
- If either -\b-s\bs or -\b-u\bu is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, s\bsh\bho\bop\bpt\bt
- shows only those options which are set or unset, respectively.
- Unless otherwise noted, the s\bsh\bho\bop\bpt\bt options are disabled (unset)
+ If either -\b-s\bs or -\b-u\bu is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, s\bsh\bho\bop\bpt\bt
+ shows only those options which are set or unset, respectively.
+ Unless otherwise noted, the s\bsh\bho\bop\bpt\bt options are disabled (unset)
by default.
- The return status when listing options is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs
- are enabled, non-zero otherwise. When setting or unsetting op-
- tions, the return status is zero unless an _\bo_\bp_\bt_\bn_\ba_\bm_\be is not a
+ The return status when listing options is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs
+ are enabled, non-zero otherwise. When setting or unsetting op-
+ tions, the return status is zero unless an _\bo_\bp_\bt_\bn_\ba_\bm_\be is not a
valid shell option.
The list of s\bsh\bho\bop\bpt\bt options is:
a\bas\bss\bso\boc\bc_\b_e\bex\bxp\bpa\ban\bnd\bd_\b_o\bon\bnc\bce\be
- If set, the shell suppresses multiple evaluation of as-
- sociative array subscripts during arithmetic expression
- evaluation, while executing builtins that can perform
- variable assignments, and while executing builtins that
+ If set, the shell suppresses multiple evaluation of as-
+ sociative array subscripts during arithmetic expression
+ evaluation, while executing builtins that can perform
+ variable assignments, and while executing builtins that
perform array dereferencing.
- 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 filename is printed, and the com-
- mand proceeds. This option is only used by interactive
+ ter, and one character too many. If a correction is
+ found, the corrected filename is printed, and the com-
+ mand proceeds. This option is only used by interactive
shells.
c\bch\bhe\bec\bck\bkh\bha\bas\bsh\bh
If set, b\bba\bas\bsh\bh checks that a command found in the hash ta-
- ble exists before trying to execute it. If a hashed
- command no longer exists, a normal path search is per-
+ ble exists before trying to execute it. If a hashed
+ command no longer exists, a normal path search is per-
formed.
c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs
If set, b\bba\bas\bsh\bh lists the status of any stopped and running
- jobs before exiting an interactive shell. If any jobs
+ jobs before exiting an interactive shell. If any jobs
are running, this causes the exit to be deferred until a
- second exit is attempted without an intervening command
- (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The shell always post-
+ second exit is attempted without an intervening command
+ (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The shell always post-
pones exiting if any jobs are stopped.
c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be
- If set, b\bba\bas\bsh\bh checks the window size after each external
- (non-builtin) command and, if necessary, updates the
- values of L\bLI\bIN\bNE\bES\bS and C\bCO\bOL\bLU\bUM\bMN\bNS\bS. This option is enabled by
+ If set, b\bba\bas\bsh\bh checks the window size after each external
+ (non-builtin) command and, if necessary, updates the
+ values of L\bLI\bIN\bNE\bES\bS and C\bCO\bOL\bLU\bUM\bMN\bNS\bS. This option is enabled by
default.
- 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. This option is
- enabled by default, but only has an effect if command
- history is enabled, as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under H\bHI\bIS\bS-\b-
+ 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. This option is
+ enabled by default, but only has an effect if command
+ history is enabled, as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under H\bHI\bIS\bS-\b-
T\bTO\bOR\bRY\bY.
c\bco\bom\bmp\bpa\bat\bt3\b31\b1
c\bco\bom\bmp\bpa\bat\bt3\b32\b2
c\bco\bom\bmp\bpa\bat\bt4\b43\b3
c\bco\bom\bmp\bpa\bat\bt4\b44\b4
c\bco\bom\bmp\bpa\bat\bt5\b50\b0
- These control aspects of the shell's compatibility mode
+ These control aspects of the shell's compatibility mode
(see S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
c\bco\bom\bmp\bpl\ble\bet\bte\be_\b_f\bfu\bul\bll\blq\bqu\buo\bot\bte\be
- If set, b\bba\bas\bsh\bh quotes all shell metacharacters in file-
- names and directory names when performing completion.
+ If set, b\bba\bas\bsh\bh quotes all shell metacharacters in file-
+ names and directory names when performing completion.
If not set, b\bba\bas\bsh\bh removes metacharacters such as the dol-
- lar sign from the set of characters that will be quoted
- in completed filenames when these metacharacters appear
- in shell variable references in words to be completed.
- This means that dollar signs in variable names that ex-
- pand to directories will not be quoted; however, any
- dollar signs appearing in filenames will not be quoted,
- either. This is active only when bash is using back-
- slashes to quote completed filenames. This variable is
- set by default, which is the default bash behavior in
+ lar sign from the set of characters that will be quoted
+ in completed filenames when these metacharacters appear
+ in shell variable references in words to be completed.
+ This means that dollar signs in variable names that ex-
+ pand to directories will not be quoted; however, any
+ dollar signs appearing in filenames will not be quoted,
+ either. This is active only when bash is using back-
+ slashes to quote completed filenames. This variable is
+ set by default, which is the default bash behavior in
versions through 4.2.
d\bdi\bir\bre\bex\bxp\bpa\ban\bnd\bd
- If set, b\bba\bas\bsh\bh replaces directory names with the results
- of word expansion when performing filename completion.
- This changes the contents of the readline editing buf-
- fer. If not set, b\bba\bas\bsh\bh attempts to preserve what the
+ If set, b\bba\bas\bsh\bh replaces directory names with the results
+ of word expansion when performing filename completion.
+ This changes the contents of the readline editing buf-
+ fer. If not set, b\bba\bas\bsh\bh attempts to preserve what the
user typed.
d\bdi\bir\brs\bsp\bpe\bel\bll\bl
- If set, b\bba\bas\bsh\bh attempts spelling correction on directory
- names during word completion if the directory name ini-
+ If set, b\bba\bas\bsh\bh attempts spelling correction on directory
+ names during word completion if the directory name ini-
tially supplied does not exist.
- d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a `.' in
- the results of pathname expansion. The filenames `\b``\b`.\b.'\b''\b'
- and `\b``\b`.\b..\b.'\b''\b' must always be matched explicitly, even if
+ d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a `.' in
+ the results of pathname expansion. The filenames `\b``\b`.\b.'\b''\b'
+ and `\b``\b`.\b..\b.'\b''\b' must always be matched explicitly, even if
d\bdo\bot\btg\bgl\blo\bob\bb is set.
e\bex\bxe\bec\bcf\bfa\bai\bil\bl
If set, a non-interactive shell will not exit if it can-
- not execute the file specified as an argument to the
- e\bex\bxe\bec\bc builtin command. An interactive shell does not
+ not execute the file specified as an argument to the
+ e\bex\bxe\bec\bc builtin command. An interactive shell does not
exit if e\bex\bxe\bec\bc fails.
e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs
If set, aliases are expanded as described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) un-
- der A\bAL\bLI\bIA\bAS\bSE\bES\bS. This option is enabled by default for in-
+ der A\bAL\bLI\bIA\bAS\bSE\bES\bS. This option is enabled by default for in-
teractive shells.
e\bex\bxt\btd\bde\beb\bbu\bug\bg
- If set at shell invocation, or in a shell startup file,
+ If set at shell invocation, or in a shell startup file,
arrange to execute the debugger profile before the shell
- starts, identical to the -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option. If set af-
- ter invocation, behavior intended for use by debuggers
+ starts, identical to the -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option. If set af-
+ ter invocation, behavior intended for use by debuggers
is enabled:
1\b1.\b. The -\b-F\bF option to the d\bde\bec\bcl\bla\bar\bre\be builtin displays the
source file name and line number corresponding to
each function name supplied as an argument.
- 2\b2.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
- non-zero value, the next command is skipped and
+ 2\b2.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
+ non-zero value, the next command is skipped and
not executed.
- 3\b3.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
- value of 2, and the shell is executing in a sub-
- routine (a shell function or a shell script exe-
- cuted by the .\b. or s\bso\bou\bur\brc\bce\be builtins), the shell
+ 3\b3.\b. If the command run by the D\bDE\bEB\bBU\bUG\bG trap returns a
+ value of 2, and the shell is executing in a sub-
+ routine (a shell function or a shell script exe-
+ cuted by the .\b. or s\bso\bou\bur\brc\bce\be builtins), the shell
simulates a call to r\bre\bet\btu\bur\brn\bn.
- 4\b4.\b. B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
+ 4\b4.\b. B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
in their descriptions in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
- 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\bR trap.
e\bex\bxt\btg\bgl\blo\bob\bb If set, the extended pattern matching features described
in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn are enabled.
e\bex\bxt\btq\bqu\buo\bot\bte\be
- If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
- within $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b} expansions enclosed in double
+ If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
+ within $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b} expansions enclosed in double
quotes. This option is enabled by default.
f\bfa\bai\bil\blg\bgl\blo\bob\bb
- If set, patterns which fail to match filenames during
+ If set, patterns which fail to match filenames during
pathname expansion result in an expansion error.
f\bfo\bor\brc\bce\be_\b_f\bfi\big\bgn\bno\bor\bre\be
- If set, the suffixes specified by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
- variable cause words to be ignored when performing word
+ If set, the suffixes specified by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
+ variable cause words to be ignored when performing word
completion even if the ignored words are the only possi-
- ble completions. See S\bSH\bHE\bEL\bLL\bL V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b) for a
- description of F\bFI\bIG\bGN\bNO\bOR\bRE\bE. This option is enabled by de-
+ ble completions. See S\bSH\bHE\bEL\bLL\bL V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b) for a
+ description of F\bFI\bIG\bGN\bNO\bOR\bRE\bE. This option is enabled by de-
fault.
g\bgl\blo\bob\bba\bas\bsc\bci\bii\bir\bra\ban\bng\bge\bes\bs
- If set, range expressions used in pattern matching
- bracket expressions (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg in _\bb_\ba_\bs_\bh_\b(_\b1_\b))
+ If set, range expressions used in pattern matching
+ bracket expressions (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg in _\bb_\ba_\bs_\bh_\b(_\b1_\b))
behave as if in the traditional C locale when performing
- comparisons. That is, the current locale's collating
- sequence is not taken into account, so b\bb will not col-
- late between A\bA and B\bB, and upper-case and lower-case
+ comparisons. That is, the current locale's collating
+ sequence is not taken into account, so b\bb will not col-
+ late between A\bA and B\bB, and upper-case and lower-case
ASCII characters will collate together.
g\bgl\blo\bob\bbs\bsk\bki\bip\bpd\bdo\bot\bts\bs
- If set, pathname expansion will never match the file-
+ If set, pathname expansion will never match the file-
names `\b``\b`.\b.'\b''\b' and `\b``\b`.\b..\b.'\b''\b', even if the pattern begins with
a `\b``\b`.\b.'\b''\b'. This option is enabled by default.
g\bgl\blo\bob\bbs\bst\bta\bar\br
If set, the pattern *\b**\b* used in a pathname expansion con-
- text will match all files and zero or more directories
- and subdirectories. If the pattern is followed by a /\b/,
+ text will match all files and zero or more directories
+ and subdirectories. If the pattern is followed by a /\b/,
only directories and subdirectories match.
g\bgn\bnu\bu_\b_e\ber\brr\brf\bfm\bmt\bt
GNU error message format.
h\bhi\bis\bst\bta\bap\bpp\bpe\ben\bnd\bd
- If set, the history list is appended to the file named
+ If set, the history list is appended to the file named
by the value of the H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE variable when the shell ex-
its, rather than overwriting the file.
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 in
+ perform hostname completion when a word containing a @\b@
+ is being completed (see C\bCo\bom\bmp\bpl\ble\bet\bti\bin\bng\bg under R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE in
_\bb_\ba_\bs_\bh_\b(_\b1_\b)). This is enabled by default.
h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt
active login shell exits.
i\bin\bnh\bhe\ber\bri\bit\bt_\b_e\ber\brr\bre\bex\bxi\bit\bt
- If set, command substitution inherits the value of the
- e\ber\brr\bre\bex\bxi\bit\bt option, instead of unsetting it in the subshell
- environment. This option is enabled when _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be is
+ If set, command substitution inherits the value of the
+ e\ber\brr\bre\bex\bxi\bit\bt option, instead of unsetting it in the subshell
+ environment. This option is enabled when _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be is
enabled.
i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs
If set, allow a word beginning with #\b# to cause that word
- and all remaining characters on that line to be ignored
+ and all remaining characters on that line to be ignored
in an interactive shell (see C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). This
option is enabled by default.
l\bla\bas\bst\btp\bpi\bip\bpe\be
- If set, and job control is not active, the shell runs
+ If set, and job control is not active, the shell runs
the last command of a pipeline not executed in the back-
ground in the current shell environment.
- l\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.
tribute is not inherited.
l\blo\boc\bca\bal\blv\bva\bar\br_\b_u\bun\bns\bse\bet\bt
- If set, calling u\bun\bns\bse\bet\bt on local variables in previous
- function scopes marks them so subsequent lookups find
- them unset until that function returns. This is identi-
- cal to the behavior of unsetting local variables at the
+ If set, calling u\bun\bns\bse\bet\bt on local variables in previous
+ function scopes marks them so subsequent lookups find
+ them unset until that function returns. This is identi-
+ cal to the behavior of unsetting local variables at the
current function scope.
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
+ The shell sets this option if it is started as a login
shell (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The value may not be
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 at-
- tempt to search the P\bPA\bAT\bTH\bH for possible completions when
+ If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will not at-
+ tempt 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 in _\bb_\ba_\bs_\bh_\b(_\b1_\b)).
n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh
- If set, b\bba\bas\bsh\bh matches patterns in a case-insensitive
+ If set, b\bba\bas\bsh\bh matches patterns in a case-insensitive
fashion when performing matching while executing c\bca\bas\bse\be or
[\b[[\b[ conditional commands, when performing pattern substi-
- tution word expansions, or when filtering possible com-
+ tution word expansions, or when filtering possible com-
pletions as part of programmable completion.
n\bno\boe\bex\bxp\bpa\ban\bnd\bd_\b_t\btr\bra\ban\bns\bsl\bla\bat\bti\bio\bon\bn
- If set, b\bba\bas\bsh\bh encloses the translated results of $"..."
- quoting in single quotes instead of double quotes. If
+ If set, b\bba\bas\bsh\bh encloses the translated results of $"..."
+ quoting in single quotes instead of double quotes. If
the string is not translated, this has no effect.
n\bnu\bul\bll\blg\bgl\blo\bob\bb
- If set, 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 in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) to expand to a null
+ 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 in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) to expand to a null
string, rather than themselves.
p\bpa\bat\bts\bsu\bub\bb_\b_r\bre\bep\bpl\bla\bac\bce\bem\bme\ben\bnt\bt
If set, b\bba\bas\bsh\bh expands occurrences of &\b& in the replacement
- string of pattern substitution to the text matched by
- the pattern, as described under P\bPa\bar\bra\bam\bme\bet\bte\ber\br E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in
+ string of pattern substitution to the text matched by
+ the pattern, as described under P\bPa\bar\bra\bam\bme\bet\bte\ber\br E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn in
_\bb_\ba_\bs_\bh_\b(_\b1_\b). This option is enabled by default.
p\bpr\bro\bog\bgc\bco\bom\bmp\bp
If set, the programmable completion facilities (see P\bPr\bro\bo-\b-
- g\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) are enabled. This op-
+ g\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) are enabled. This op-
tion is enabled by default.
p\bpr\bro\bog\bgc\bco\bom\bmp\bp_\b_a\bal\bli\bia\bas\bs
- If set, and programmable completion is enabled, b\bba\bas\bsh\bh
- treats a command name that doesn't have any completions
- as a possible alias and attempts alias expansion. If it
- has an alias, b\bba\bas\bsh\bh attempts programmable completion us-
+ If set, and programmable completion is enabled, b\bba\bas\bsh\bh
+ treats a command name that doesn't have any completions
+ as a possible alias and attempts alias expansion. If it
+ has an alias, b\bba\bas\bsh\bh attempts programmable completion us-
ing the command word resulting from the expanded alias.
p\bpr\bro\bom\bmp\bpt\btv\bva\bar\brs\bs
If set, prompt strings undergo parameter expansion, com-
- mand substitution, arithmetic expansion, and quote re-
- moval after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG in
+ mand substitution, arithmetic expansion, and quote re-
+ moval after being expanded as described in P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG in
_\bb_\ba_\bs_\bh_\b(_\b1_\b). This option is enabled by default.
r\bre\bes\bst\btr\bri\bic\bct\bte\bed\bd_\b_s\bsh\bhe\bel\bll\bl
- The shell sets this option if it is started in re-
- stricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The
- value may not be changed. This is not reset when the
- startup files are executed, allowing the startup files
+ The shell sets this option if it is started in re-
+ stricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). The
+ value may not be changed. This is not reset when the
+ startup files are executed, allowing the startup files
to discover whether or not a shell is restricted.
s\bsh\bhi\bif\bft\bt_\b_v\bve\ber\brb\bbo\bos\bse\be
- If set, the s\bsh\bhi\bif\bft\bt builtin prints an error message when
+ If set, the s\bsh\bhi\bif\bft\bt builtin prints an error message when
the shift count exceeds the number of positional parame-
ters.
s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh
If set, the .\b. (s\bso\bou\bur\brc\bce\be) builtin uses the value of P\bPA\bAT\bTH\bH to
- find the directory containing the file supplied as an
+ find the directory containing the file supplied as an
argument. This option is enabled by default.
v\bva\bar\brr\bre\bed\bdi\bir\br_\b_c\bcl\blo\bos\bse\be
- If set, the shell automatically closes file descriptors
+ If set, the shell automatically closes file descriptors
assigned using the _\b{_\bv_\ba_\br_\bn_\ba_\bm_\be_\b} redirection syntax (see R\bRE\bE-\b-
- D\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) instead of leaving them open when
+ D\bDI\bIR\bRE\bEC\bCT\bTI\bIO\bON\bN in _\bb_\ba_\bs_\bh_\b(_\b1_\b)) instead of leaving them open when
the command completes.
x\bxp\bpg\bg_\b_e\bec\bch\bho\bo
- If set, the e\bec\bch\bho\bo builtin expands backslash-escape se-
+ If set, the e\bec\bch\bho\bo builtin expands backslash-escape se-
quences 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. A login shell, or a shell without job control enabled,
- cannot be suspended; the -\b-f\bf option can be used to override this
- and force the suspension. The return status is 0 unless the
- shell is a login shell or job control is not enabled and -\b-f\bf is
+ Suspend the execution of this shell until it receives a S\bSI\bIG\bGC\bCO\bON\bNT\bT
+ signal. A login shell, or a shell without job control enabled,
+ cannot be suspended; the -\b-f\bf option can be used to override this
+ and force the suspension. The return status is 0 unless the
+ shell is a login shell or job control is not enabled and -\b-f\bf is
not supplied.
t\bte\bes\bst\bt _\be_\bx_\bp_\br
[\b[ _\be_\bx_\bp_\br ]\b]
Return a status of 0 (true) or 1 (false) depending on the evalu-
ation of the conditional expression _\be_\bx_\bp_\br. Each operator and op-
- erand must be a separate argument. Expressions are composed of
- the primaries described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
+ erand must be a separate argument. Expressions are composed of
+ the primaries described in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
S\bSI\bIO\bON\bNS\bS. t\bte\bes\bst\bt does not accept any options, nor does it accept and
ignore an argument of -\b--\b- as signifying the end of options.
- Expressions may be combined using the following operators,
- listed in decreasing order of precedence. The evaluation de-
- pends on the number of arguments; see below. Operator prece-
+ Expressions may be combined using the following operators,
+ listed in decreasing order of precedence. The evaluation de-
+ pends on the number of arguments; see below. Operator prece-
dence is used when there are five or more arguments.
!\b! _\be_\bx_\bp_\br True if _\be_\bx_\bp_\br is false.
(\b( _\be_\bx_\bp_\br )\b)
- Returns the value of _\be_\bx_\bp_\br. This may be used to override
+ Returns the value of _\be_\bx_\bp_\br. This may be used to override
the normal precedence of operators.
_\be_\bx_\bp_\br_\b1 -a\ba _\be_\bx_\bp_\br_\b2
True if both _\be_\bx_\bp_\br_\b1 and _\be_\bx_\bp_\br_\b2 are true.
null.
2 arguments
If the first argument is !\b!, the expression is true if and
- only if the second argument is null. If the first argu-
- ment is one of the unary conditional operators listed in
- _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS, the expression is
+ only if the second argument is null. If the first argu-
+ ment is one of the unary conditional operators listed in
+ _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS, the expression is
true if the unary test is true. If the first argument is
not a valid unary conditional operator, the expression is
false.
3 arguments
The following conditions are applied in the order listed.
- If the second argument is one of the binary conditional
- operators listed in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
- S\bSI\bIO\bON\bNS\bS, the result of the expression is the result of the
- binary test using the first and third arguments as oper-
- ands. The -\b-a\ba and -\b-o\bo operators are considered binary op-
+ If the second argument is one of the binary conditional
+ operators listed in _\bb_\ba_\bs_\bh_\b(_\b1_\b) under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bS-\b-
+ S\bSI\bIO\bON\bNS\bS, the result of the expression is the result of the
+ binary test using the first and third arguments as oper-
+ ands. The -\b-a\ba and -\b-o\bo operators are considered binary op-
erators when there are three arguments. If the first ar-
- gument is !\b!, the value is the negation of the two-argu-
- ment test using the second and third arguments. If the
+ gument is !\b!, the value is the negation of the two-argu-
+ ment test using the second and third arguments. If the
first argument is exactly (\b( and the third argument is ex-
- actly )\b), the result is the one-argument test of the sec-
+ actly )\b), the result is the one-argument test of the sec-
ond argument. Otherwise, the expression is false.
4 arguments
The following conditions are applied in the order listed.
If the first argument is !\b!, the result is the negation of
- the three-argument expression composed of the remaining
- arguments. the two-argument test using the second and
- third arguments. If the first argument is exactly (\b( and
- the fourth argument is exactly )\b), the result is the two-
- argument test of the second and third arguments. Other-
+ the three-argument expression composed of the remaining
+ arguments. the two-argument test using the second and
+ third arguments. If the first argument is exactly (\b( and
+ the fourth argument is exactly )\b), the result is the two-
+ argument test of the second and third arguments. Other-
wise, the expression is parsed and evaluated according to
precedence using the rules listed above.
5 or more arguments
- The expression is parsed and evaluated according to
+ The expression is parsed and evaluated according to
precedence using the rules listed above.
- When used with t\bte\bes\bst\bt or [\b[, the <\b< and >\b> operators sort lexico-
+ When used with t\bte\bes\bst\bt or [\b[, the <\b< and >\b> operators sort lexico-
graphically using ASCII ordering.
- t\bti\bim\bme\bes\bs Print the accumulated user and system times for the shell and
+ t\bti\bim\bme\bes\bs Print the accumulated user and system times for the shell and
for processes run from the shell. The return status is 0.
t\btr\bra\bap\bp [-\b-l\blp\bp] [[_\ba_\bc_\bt_\bi_\bo_\bn] _\bs_\bi_\bg_\bs_\bp_\be_\bc ...]
The _\ba_\bc_\bt_\bi_\bo_\bn is a command that is read and executed when the shell
receives signal(s) _\bs_\bi_\bg_\bs_\bp_\be_\bc. If _\ba_\bc_\bt_\bi_\bo_\bn is absent (and there is a
- single _\bs_\bi_\bg_\bs_\bp_\be_\bc) or -\b-, each specified signal is reset to its
- original disposition (the value it had upon entrance to the
- shell). If _\ba_\bc_\bt_\bi_\bo_\bn is the null string the signal specified by
- each _\bs_\bi_\bg_\bs_\bp_\be_\bc is ignored by the shell and by the commands it in-
+ single _\bs_\bi_\bg_\bs_\bp_\be_\bc) or -\b-, each specified signal is reset to its
+ original disposition (the value it had upon entrance to the
+ shell). If _\ba_\bc_\bt_\bi_\bo_\bn is the null string the signal specified by
+ each _\bs_\bi_\bg_\bs_\bp_\be_\bc is ignored by the shell and by the commands it in-
vokes.
- If no arguments are supplied, t\btr\bra\bap\bp displays the actions associ-
+ If no arguments are supplied, t\btr\bra\bap\bp displays the actions associ-
ated with each trapped signal as a set of t\btr\bra\bap\bp commands that can
- be reused as shell input to restore the current signal disposi-
- tions. If -\b-p\bp is given, and _\ba_\bc_\bt_\bi_\bo_\bn is not present, then t\btr\bra\bap\bp
- displays the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc or, if none
+ be reused as shell input to restore the current signal disposi-
+ tions. If -\b-p\bp is given, and _\ba_\bc_\bt_\bi_\bo_\bn is not present, then t\btr\bra\bap\bp
+ displays the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc or, if none
are supplied, for all trapped signals, as a set of t\btr\bra\bap\bp commands
- that can be reused as shell input to restore the current signal
- dispositions. The -\b-P\bP option behaves similarly, but displays
- only the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc argument. -\b-P\bP re-
- quires at least one _\bs_\bi_\bg_\bs_\bp_\be_\bc argument. The -\b-P\bP or -\b-p\bp options to
- t\btr\bra\bap\bp may be used in a subshell environment (e.g., command sub-
- stitution) and, as long as they are used before t\btr\bra\bap\bp is used to
- change a signal's handling, will display the state of its par-
+ that can be reused as shell input to restore the current signal
+ dispositions. The -\b-P\bP option behaves similarly, but displays
+ only the actions associated with each _\bs_\bi_\bg_\bs_\bp_\be_\bc argument. -\b-P\bP re-
+ quires at least one _\bs_\bi_\bg_\bs_\bp_\be_\bc argument. The -\b-P\bP or -\b-p\bp options to
+ t\btr\bra\bap\bp may be used in a subshell environment (e.g., command sub-
+ stitution) and, as long as they are used before t\btr\bra\bap\bp is used to
+ change a signal's handling, will display the state of its par-
ent's traps.
- The -\b-l\bl option causes t\btr\bra\bap\bp to print a list of signal names and
- their corresponding numbers. Each _\bs_\bi_\bg_\bs_\bp_\be_\bc is either a signal
- name defined in <_\bs_\bi_\bg_\bn_\ba_\bl_\b._\bh>, or a signal number. Signal names
+ The -\b-l\bl option causes t\btr\bra\bap\bp to print a list of signal names and
+ their corresponding numbers. Each _\bs_\bi_\bg_\bs_\bp_\be_\bc is either a signal
+ name defined in <_\bs_\bi_\bg_\bn_\ba_\bl_\b._\bh>, or a signal number. Signal names
are case insensitive and the S\bSI\bIG\bG prefix is optional.
- If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bEX\bXI\bIT\bT (0) the command _\ba_\bc_\bt_\bi_\bo_\bn is executed on exit
- from the shell. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is D\bDE\bEB\bBU\bUG\bG, the command _\ba_\bc_\bt_\bi_\bo_\bn is
+ If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bEX\bXI\bIT\bT (0) the command _\ba_\bc_\bt_\bi_\bo_\bn is executed on exit
+ from the shell. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is D\bDE\bEB\bBU\bUG\bG, the command _\ba_\bc_\bt_\bi_\bo_\bn is
executed before every _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, _\bf_\bo_\br command, _\bc_\ba_\bs_\be command,
- _\bs_\be_\bl_\be_\bc_\bt command, (( arithmetic command, [[ conditional command,
+ _\bs_\be_\bl_\be_\bc_\bt command, (( arithmetic command, [[ conditional command,
arithmetic _\bf_\bo_\br command, and before the first command executes in
- a shell function (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). Refer to the
- description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin for de-
- tails of its effect on the D\bDE\bEB\bBU\bUG\bG trap. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is R\bRE\bET\bTU\bUR\bRN\bN,
- the command _\ba_\bc_\bt_\bi_\bo_\bn is executed each time a shell function or a
- script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins finishes execut-
+ a shell function (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR in _\bb_\ba_\bs_\bh_\b(_\b1_\b)). Refer to the
+ description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the s\bsh\bho\bop\bpt\bt builtin for de-
+ tails of its effect on the D\bDE\bEB\bBU\bUG\bG trap. If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is R\bRE\bET\bTU\bUR\bRN\bN,
+ the command _\ba_\bc_\bt_\bi_\bo_\bn is executed each time a shell function or a
+ script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins finishes execut-
ing.
- If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bER\bRR\bR, the command _\ba_\bc_\bt_\bi_\bo_\bn is executed whenever a
+ If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bER\bRR\bR, the command _\ba_\bc_\bt_\bi_\bo_\bn is executed whenever a
pipeline (which may consist of a single simple command), a list,
or a compound command returns a non-zero exit status, subject to
- the following conditions. The E\bER\bRR\bR trap is not executed if the
+ the following conditions. The E\bER\bRR\bR trap is not executed if the
failed command is part of the command list immediately following
- a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an _\bi_\bf statement,
+ a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an _\bi_\bf statement,
part of a command executed in a &\b&&\b& or |\b||\b| list except the command
- following the final &\b&&\b& or |\b||\b|, any command in a pipeline but the
- last, or if the command's return value is being inverted using
+ following the final &\b&&\b& or |\b||\b|, any command in a pipeline but the
+ last, or if the command's return value is being inverted using
!\b!. These are the same conditions obeyed by the e\ber\brr\bre\bex\bxi\bit\bt (-\b-e\be) op-
tion.
When the shell is not interactive, signals ignored upon entry to
the shell cannot be trapped or reset. Interactive shells permit
trapping signals ignored on entry. Trapped signals that are not
- being ignored are reset to their original values in a subshell
- or subshell environment when one is created. The return status
+ being ignored are reset to their original values in a subshell
+ or subshell environment when one is created. The return status
is false if any _\bs_\bi_\bg_\bs_\bp_\be_\bc is invalid; otherwise t\btr\bra\bap\bp returns true.
t\bty\byp\bpe\be [-\b-a\baf\bft\btp\bpP\bP] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
- With no options, indicate how each _\bn_\ba_\bm_\be would be interpreted if
+ With no options, indicate how each _\bn_\ba_\bm_\be would be interpreted if
used as a command name. If the -\b-t\bt option is used, t\bty\byp\bpe\be prints a
- string which is one of _\ba_\bl_\bi_\ba_\bs, _\bk_\be_\by_\bw_\bo_\br_\bd, _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn, _\bb_\bu_\bi_\bl_\bt_\bi_\bn, or
- _\bf_\bi_\bl_\be if _\bn_\ba_\bm_\be is an alias, shell reserved word, function,
- builtin, or executable disk file, respectively. If the _\bn_\ba_\bm_\be is
- not found, then nothing is printed, and t\bty\byp\bpe\be returns a non-zero
- exit status. If the -\b-p\bp option is used, t\bty\byp\bpe\be either returns the
- name of the executable file that would be found by searching
- $\b$P\bPA\bAT\bTH\bH if _\bn_\ba_\bm_\be were specified as a command name, or nothing if
- ``type -t name'' would not return _\bf_\bi_\bl_\be. The -\b-P\bP option forces a
- P\bPA\bAT\bTH\bH search for each _\bn_\ba_\bm_\be, even if ``type -t name'' would not
+ string which is one of _\ba_\bl_\bi_\ba_\bs, _\bk_\be_\by_\bw_\bo_\br_\bd, _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn, _\bb_\bu_\bi_\bl_\bt_\bi_\bn, or
+ _\bf_\bi_\bl_\be if _\bn_\ba_\bm_\be is an alias, shell reserved word, function,
+ builtin, or executable disk file, respectively. If the _\bn_\ba_\bm_\be is
+ not found, then nothing is printed, and t\bty\byp\bpe\be returns a non-zero
+ exit status. If the -\b-p\bp option is used, t\bty\byp\bpe\be either returns the
+ name of the executable file that would be found by searching
+ $\b$P\bPA\bAT\bTH\bH if _\bn_\ba_\bm_\be were specified as a command name, or nothing if
+ ``type -t name'' would not return _\bf_\bi_\bl_\be. The -\b-P\bP option forces a
+ P\bPA\bAT\bTH\bH search for each _\bn_\ba_\bm_\be, even if ``type -t name'' would not
return _\bf_\bi_\bl_\be. If a command is hashed, -\b-p\bp and -\b-P\bP print the hashed
- value, which is not necessarily the file that appears first in
- P\bPA\bAT\bTH\bH. If the -\b-a\ba option is used, t\bty\byp\bpe\be prints all of the places
- that contain a command named _\bn_\ba_\bm_\be. This includes aliases, re-
- served words, functions, and builtins, but the path search op-
+ value, which is not necessarily the file that appears first in
+ P\bPA\bAT\bTH\bH. If the -\b-a\ba option is used, t\bty\byp\bpe\be prints all of the places
+ that contain a command named _\bn_\ba_\bm_\be. This includes aliases, re-
+ served words, functions, and builtins, but the path search op-
tions (-\b-p\bp and -\b-P\bP) can be supplied to restrict the output to exe-
- cutable files. t\bty\byp\bpe\be does not consult the table of hashed com-
+ cutable files. t\bty\byp\bpe\be does not consult the table of hashed com-
mands when using -\b-a\ba with -\b-p\bp, and only performs a P\bPA\bAT\bTH\bH search for
- _\bn_\ba_\bm_\be. The -\b-f\bf option suppresses shell function lookup, as with
- the c\bco\bom\bmm\bma\ban\bnd\bd builtin. t\bty\byp\bpe\be returns true if all of the arguments
+ _\bn_\ba_\bm_\be. The -\b-f\bf option suppresses shell function lookup, as with
+ the c\bco\bom\bmm\bma\ban\bnd\bd builtin. t\bty\byp\bpe\be returns true if all of the arguments
are found, false if any are not found.
u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bS] -\b-a\ba
u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bS] [-\b-b\bbc\bcd\bde\bef\bfi\bik\bkl\blm\bmn\bnp\bpq\bqr\brs\bst\btu\buv\bvx\bxP\bPR\bRT\bT [_\bl_\bi_\bm_\bi_\bt]]
- Provides control over the resources available to the shell and
- to processes started by it, on systems that allow such control.
+ Provides control over the resources available to the shell and
+ to processes started by it, on systems that allow such control.
The -\b-H\bH and -\b-S\bS options specify that the hard or soft limit is set
- for the given resource. A hard limit cannot be increased by a
- non-root user once it is set; a soft limit may be increased up
- to the value of the hard limit. If neither -\b-H\bH nor -\b-S\bS is speci-
+ for the given resource. A hard limit cannot be increased by a
+ non-root user once it is set; a soft limit may be increased up
+ to the value of the hard limit. If neither -\b-H\bH nor -\b-S\bS is speci-
fied, both the soft and hard limits are set. The value of _\bl_\bi_\bm_\bi_\bt
can be a number in the unit specified for the resource or one of
the special values h\bha\bar\brd\bd, s\bso\bof\bft\bt, or u\bun\bnl\bli\bim\bmi\bit\bte\bed\bd, which stand for the
- current hard limit, the current soft limit, and no limit, re-
- spectively. If _\bl_\bi_\bm_\bi_\bt is omitted, the current value of the soft
+ current hard limit, the current soft limit, and no limit, re-
+ spectively. If _\bl_\bi_\bm_\bi_\bt is omitted, the current value of the soft
limit of the resource is printed, unless the -\b-H\bH option is given.
- When more than one resource is specified, the limit name and
- unit, if appropriate, are printed before the value. Other op-
+ When more than one resource is specified, the limit name and
+ unit, if appropriate, are printed before the value. Other op-
tions are interpreted as follows:
-\b-a\ba All current limits are reported; no limits are set
-\b-b\bb The maximum socket buffer size
-\b-c\bc The maximum size of core files created
-\b-d\bd The maximum size of a process's data segment
-\b-e\be The maximum scheduling priority ("nice")
- -\b-f\bf The maximum size of files written by the shell and its
+ -\b-f\bf The maximum size of files written by the shell and its
children
-\b-i\bi The maximum number of pending signals
-\b-k\bk The maximum number of kqueues that may be allocated
-\b-l\bl The maximum size that may be locked into memory
- -\b-m\bm The maximum resident set size (many systems do not honor
+ -\b-m\bm The maximum resident set size (many systems do not honor
this limit)
-\b-n\bn The maximum number of open file descriptors (most systems
do not allow this value to be set)
-\b-r\br The maximum real-time scheduling priority
-\b-s\bs The maximum stack size
-\b-t\bt The maximum amount of cpu time in seconds
- -\b-u\bu The maximum number of processes available to a single
+ -\b-u\bu The maximum number of processes available to a single
user
- -\b-v\bv The maximum amount of virtual memory available to the
+ -\b-v\bv The maximum amount of virtual memory available to the
shell and, on some systems, to its children
-\b-x\bx The maximum number of file locks
-\b-P\bP The maximum number of pseudoterminals
- -\b-R\bR The maximum time a real-time process can run before
+ -\b-R\bR The maximum time a real-time process can run before
blocking, in microseconds
-\b-T\bT The maximum number of threads
- If _\bl_\bi_\bm_\bi_\bt is given, and the -\b-a\ba option is not used, _\bl_\bi_\bm_\bi_\bt is the
- new value of the specified resource. If no option is given,
- then -\b-f\bf is assumed. Values are in 1024-byte increments, except
- for -\b-t\bt, which is in seconds; -\b-R\bR, which is in microseconds; -\b-p\bp,
- which is in units of 512-byte blocks; -\b-P\bP, -\b-T\bT, -\b-b\bb, -\b-k\bk, -\b-n\bn, and
- -\b-u\bu, which are unscaled values; and, when in posix mode, -\b-c\bc and
- -\b-f\bf, which are in 512-byte increments. The return status is 0
- unless an invalid option or argument is supplied, or an error
+ If _\bl_\bi_\bm_\bi_\bt is given, and the -\b-a\ba option is not used, _\bl_\bi_\bm_\bi_\bt is the
+ new value of the specified resource. If no option is given,
+ then -\b-f\bf is assumed. Values are in 1024-byte increments, except
+ for -\b-t\bt, which is in seconds; -\b-R\bR, which is in microseconds; -\b-p\bp,
+ which is in units of 512-byte blocks; -\b-P\bP, -\b-T\bT, -\b-b\bb, -\b-k\bk, -\b-n\bn, and
+ -\b-u\bu, which are unscaled values; and, when in posix mode, -\b-c\bc and
+ -\b-f\bf, which are in 512-byte increments. The return status is 0
+ unless an invalid option or argument is supplied, or an error
occurs while setting a new limit.
u\bum\bma\bas\bsk\bk [-\b-p\bp] [-\b-S\bS] [_\bm_\bo_\bd_\be]
The user file-creation mask is set to _\bm_\bo_\bd_\be. If _\bm_\bo_\bd_\be begins with
- a digit, it is interpreted as an octal number; otherwise it is
- interpreted as a symbolic mode mask similar to that accepted by
- _\bc_\bh_\bm_\bo_\bd(1). If _\bm_\bo_\bd_\be is omitted, the current value of the mask is
- printed. The -\b-S\bS option causes the mask to be printed in sym-
- bolic form; the default output is an octal number. If the -\b-p\bp
+ a digit, it is interpreted as an octal number; otherwise it is
+ interpreted as a symbolic mode mask similar to that accepted by
+ _\bc_\bh_\bm_\bo_\bd(1). If _\bm_\bo_\bd_\be is omitted, the current value of the mask is
+ printed. The -\b-S\bS option causes the mask to be printed in sym-
+ bolic form; the default output is an octal number. If the -\b-p\bp
option is supplied, and _\bm_\bo_\bd_\be is omitted, the output is in a form
that may be reused as input. The return status is 0 if the mode
- was successfully changed or if no _\bm_\bo_\bd_\be argument was supplied,
+ was successfully changed or if no _\bm_\bo_\bd_\be argument was supplied,
and false otherwise.
u\bun\bna\bal\bli\bia\bas\bs [-a\ba] [_\bn_\ba_\bm_\be ...]
- Remove each _\bn_\ba_\bm_\be from the list of defined aliases. If -\b-a\ba is
- supplied, all alias definitions are removed. The return value
+ Remove each _\bn_\ba_\bm_\be from the list of defined aliases. If -\b-a\ba is
+ supplied, all alias definitions are removed. The return value
is true unless a supplied _\bn_\ba_\bm_\be is not a defined alias.
u\bun\bns\bse\bet\bt [-f\bfv\bv] [-n\bn] [_\bn_\ba_\bm_\be ...]
- For each _\bn_\ba_\bm_\be, remove the corresponding variable or function.
+ For each _\bn_\ba_\bm_\be, remove the corresponding variable or function.
If the -\b-v\bv option is given, each _\bn_\ba_\bm_\be refers to a shell variable,
- and that variable is removed. Read-only variables may not be
- unset. If -\b-f\bf is specified, each _\bn_\ba_\bm_\be refers to a shell func-
- tion, and the function definition is removed. If the -\b-n\bn option
- is supplied, and _\bn_\ba_\bm_\be is a variable with the _\bn_\ba_\bm_\be_\br_\be_\bf attribute,
- _\bn_\ba_\bm_\be will be unset rather than the variable it references. -\b-n\bn
- has no effect if the -\b-f\bf option is supplied. If no options are
- supplied, each _\bn_\ba_\bm_\be refers to a variable; if there is no vari-
- able by that name, a function with that name, if any, is unset.
- Each unset variable or function is removed from the environment
- passed to subsequent commands. If any of B\bBA\bAS\bSH\bH_\b_A\bAL\bLI\bIA\bAS\bSE\bES\bS,
+ and that variable is removed. Read-only variables may not be
+ unset. If -\b-f\bf is specified, each _\bn_\ba_\bm_\be refers to a shell func-
+ tion, and the function definition is removed. If the -\b-n\bn option
+ is supplied, and _\bn_\ba_\bm_\be is a variable with the _\bn_\ba_\bm_\be_\br_\be_\bf attribute,
+ _\bn_\ba_\bm_\be will be unset rather than the variable it references. -\b-n\bn
+ has no effect if the -\b-f\bf option is supplied. If no options are
+ supplied, each _\bn_\ba_\bm_\be refers to a variable; if there is no vari-
+ able by that name, a function with that name, if any, is unset.
+ Each unset variable or function is removed from the environment
+ passed to subsequent commands. If any of B\bBA\bAS\bSH\bH_\b_A\bAL\bLI\bIA\bAS\bSE\bES\bS,
B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV0\b0, B\bBA\bAS\bSH\bH_\b_C\bCM\bMD\bDS\bS, B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMM\bMA\bAN\bND\bD, B\bBA\bAS\bSH\bH_\b_S\bSU\bUB\bBS\bSH\bHE\bEL\bLL\bL, B\bBA\bAS\bSH\bHP\bPI\bID\bD,
- C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS, D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK, E\bEP\bPO\bOC\bCH\bHR\bRE\bEA\bAL\bLT\bTI\bIM\bME\bE, E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS, F\bFU\bUN\bNC\bC-\b-
- N\bNA\bAM\bME\bE, G\bGR\bRO\bOU\bUP\bPS\bS, H\bHI\bIS\bST\bTC\bCM\bMD\bD, L\bLI\bIN\bNE\bEN\bNO\bO, R\bRA\bAN\bND\bDO\bOM\bM, S\bSE\bEC\bCO\bON\bND\bDS\bS, or S\bSR\bRA\bAN\bND\bDO\bOM\bM are
+ C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS, D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK, E\bEP\bPO\bOC\bCH\bHR\bRE\bEA\bAL\bLT\bTI\bIM\bME\bE, E\bEP\bPO\bOC\bCH\bHS\bSE\bEC\bCO\bON\bND\bDS\bS, F\bFU\bUN\bNC\bC-\b-
+ N\bNA\bAM\bME\bE, G\bGR\bRO\bOU\bUP\bPS\bS, H\bHI\bIS\bST\bTC\bCM\bMD\bD, L\bLI\bIN\bNE\bEN\bNO\bO, R\bRA\bAN\bND\bDO\bOM\bM, S\bSE\bEC\bCO\bON\bND\bDS\bS, or S\bSR\bRA\bAN\bND\bDO\bOM\bM are
unset, they lose their special properties, even if they are sub-
sequently reset. The exit status is true unless a _\bn_\ba_\bm_\be is read-
only or may not be unset.
w\bwa\bai\bit\bt [-\b-f\bfn\bn] [-\b-p\bp _\bv_\ba_\br_\bn_\ba_\bm_\be] [_\bi_\bd _\b._\b._\b.]
Wait for each specified child process and return its termination
- status. Each _\bi_\bd may be a process ID or a job specification; if
- a job spec is given, all processes in that job's pipeline are
- waited for. If _\bi_\bd is not given, w\bwa\bai\bit\bt waits for all running
- background jobs and the last-executed process substitution, if
+ status. Each _\bi_\bd may be a process ID or a job specification; if
+ a job spec is given, all processes in that job's pipeline are
+ waited for. If _\bi_\bd is not given, w\bwa\bai\bit\bt waits for all running
+ background jobs and the last-executed process substitution, if
its process id is the same as $\b$!\b!, and the return status is zero.
- If the -\b-n\bn option is supplied, w\bwa\bai\bit\bt waits for a single job from
+ If the -\b-n\bn option is supplied, w\bwa\bai\bit\bt waits for a single job from
the list of _\bi_\bds or, if no _\bi_\bds are supplied, any job, to complete
- and returns its exit status. If none of the supplied arguments
+ and returns its exit status. If none of the supplied arguments
is a child of the shell, or if no arguments are supplied and the
- shell has no unwaited-for children, the exit status is 127. If
- the -\b-p\bp option is supplied, the process or job identifier of the
- job for which the exit status is returned is assigned to the
- variable _\bv_\ba_\br_\bn_\ba_\bm_\be named by the option argument. The variable
- will be unset initially, before any assignment. This is useful
- only when the -\b-n\bn option is supplied. Supplying the -\b-f\bf option,
- when job control is enabled, forces w\bwa\bai\bit\bt to wait for _\bi_\bd to ter-
+ shell has no unwaited-for children, the exit status is 127. If
+ the -\b-p\bp option is supplied, the process or job identifier of the
+ job for which the exit status is returned is assigned to the
+ variable _\bv_\ba_\br_\bn_\ba_\bm_\be named by the option argument. The variable
+ will be unset initially, before any assignment. This is useful
+ only when the -\b-n\bn option is supplied. Supplying the -\b-f\bf option,
+ when job control is enabled, forces w\bwa\bai\bit\bt to wait for _\bi_\bd to ter-
minate before returning its status, instead of returning when it
- changes status. If _\bi_\bd specifies a non-existent process or job,
- the return status is 127. If w\bwa\bai\bit\bt is interrupted by a signal,
- the return status will be greater than 128, as described under
- S\bSI\bIG\bGN\bNA\bAL\bLS\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b). Otherwise, the return status is the exit
+ changes status. If _\bi_\bd specifies a non-existent process or job,
+ the return status is 127. If w\bwa\bai\bit\bt is interrupted by a signal,
+ the return status will be greater than 128, as described under
+ S\bSI\bIG\bGN\bNA\bAL\bLS\bS in _\bb_\ba_\bs_\bh_\b(_\b1_\b). Otherwise, the return status is the exit
status of the last process or job waited for.
S\bSH\bHE\bEL\bLL\bL C\bCO\bOM\bMP\bPA\bAT\bTI\bIB\bBI\bIL\bLI\bIT\bTY\bY M\bMO\bOD\bDE\bE
- Bash-4.0 introduced the concept of a _\bs_\bh_\be_\bl_\bl _\bc_\bo_\bm_\bp_\ba_\bt_\bi_\bb_\bi_\bl_\bi_\bt_\by _\bl_\be_\bv_\be_\bl, speci-
- fied as a set of options to the shopt builtin ( c\bco\bom\bmp\bpa\bat\bt3\b31\b1, c\bco\bom\bmp\bpa\bat\bt3\b32\b2,
- c\bco\bom\bmp\bpa\bat\bt4\b40\b0, c\bco\bom\bmp\bpa\bat\bt4\b41\b1, and so on). There is only one current compatibil-
- ity level -- each option is mutually exclusive. The compatibility
- level is intended to allow users to select behavior from previous ver-
- sions that is incompatible with newer versions while they migrate
- scripts to use current features and behavior. It's intended to be a
+ Bash-4.0 introduced the concept of a _\bs_\bh_\be_\bl_\bl _\bc_\bo_\bm_\bp_\ba_\bt_\bi_\bb_\bi_\bl_\bi_\bt_\by _\bl_\be_\bv_\be_\bl, speci-
+ fied as a set of options to the shopt builtin ( c\bco\bom\bmp\bpa\bat\bt3\b31\b1, c\bco\bom\bmp\bpa\bat\bt3\b32\b2,
+ c\bco\bom\bmp\bpa\bat\bt4\b40\b0, c\bco\bom\bmp\bpa\bat\bt4\b41\b1, and so on). There is only one current compatibil-
+ ity level -- each option is mutually exclusive. The compatibility
+ level is intended to allow users to select behavior from previous ver-
+ sions that is incompatible with newer versions while they migrate
+ scripts to use current features and behavior. It's intended to be a
temporary solution.
- This section does not mention behavior that is standard for a particu-
- lar version (e.g., setting c\bco\bom\bmp\bpa\bat\bt3\b32\b2 means that quoting the rhs of the
- regexp matching operator quotes special regexp characters in the word,
+ This section does not mention behavior that is standard for a particu-
+ lar version (e.g., setting c\bco\bom\bmp\bpa\bat\bt3\b32\b2 means that quoting the rhs of the
+ regexp matching operator quotes special regexp characters in the word,
which is default behavior in bash-3.2 and subsequent versions).
- If a user enables, say, c\bco\bom\bmp\bpa\bat\bt3\b32\b2, it may affect the behavior of other
- compatibility levels up to and including the current compatibility
- level. The idea is that each compatibility level controls behavior
- that changed in that version of b\bba\bas\bsh\bh, but that behavior may have been
- present in earlier versions. For instance, the change to use locale-
- based comparisons with the [\b[[\b[ command came in bash-4.1, and earlier
+ If a user enables, say, c\bco\bom\bmp\bpa\bat\bt3\b32\b2, it may affect the behavior of other
+ compatibility levels up to and including the current compatibility
+ level. The idea is that each compatibility level controls behavior
+ that changed in that version of b\bba\bas\bsh\bh, but that behavior may have been
+ present in earlier versions. For instance, the change to use locale-
+ based comparisons with the [\b[[\b[ command came in bash-4.1, and earlier
versions used ASCII-based comparisons, so enabling c\bco\bom\bmp\bpa\bat\bt3\b32\b2 will enable
- ASCII-based comparisons as well. That granularity may not be suffi-
- cient for all uses, and as a result users should employ compatibility
- levels carefully. Read the documentation for a particular feature to
+ ASCII-based comparisons as well. That granularity may not be suffi-
+ cient for all uses, and as a result users should employ compatibility
+ levels carefully. Read the documentation for a particular feature to
find out the current behavior.
- Bash-4.3 introduced a new shell variable: B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT. The value as-
+ Bash-4.3 introduced a new shell variable: B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT. The value as-
signed to this variable (a decimal version number like 4.2, or an inte-
- ger corresponding to the c\bco\bom\bmp\bpa\bat\bt_\bN_\bN option, like 42) determines the com-
+ ger corresponding to the c\bco\bom\bmp\bpa\bat\bt_\bN_\bN option, like 42) determines the com-
patibility level.
- Starting with bash-4.4, Bash has begun deprecating older compatibility
- levels. Eventually, the options will be removed in favor of B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bM-\b-
+ Starting with bash-4.4, Bash has begun deprecating older compatibility
+ levels. Eventually, the options will be removed in favor of B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bM-\b-
P\bPA\bAT\bT.
- Bash-5.0 is the final version for which there will be an individual
- shopt option for the previous version. Users should use B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT on
+ Bash-5.0 is the final version for which there will be an individual
+ shopt option for the previous version. Users should use B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT on
bash-5.0 and later versions.
- The following table describes the behavior changes controlled by each
+ The following table describes the behavior changes controlled by each
compatibility level setting. The c\bco\bom\bmp\bpa\bat\bt_\bN_\bN tag is used as shorthand for
setting the compatibility level to _\bN_\bN using one of the following mecha-
- nisms. For versions prior to bash-5.0, the compatibility level may be
- set using the corresponding c\bco\bom\bmp\bpa\bat\bt_\bN_\bN shopt option. For bash-4.3 and
- later versions, the B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT variable is preferred, and it is re-
+ nisms. For versions prior to bash-5.0, the compatibility level may be
+ set using the corresponding c\bco\bom\bmp\bpa\bat\bt_\bN_\bN shopt option. For bash-4.3 and
+ later versions, the B\bBA\bAS\bSH\bH_\b_C\bCO\bOM\bMP\bPA\bAT\bT variable is preferred, and it is re-
quired for bash-5.1 and later versions.
c\bco\bom\bmp\bpa\bat\bt3\b31\b1
ator (=~) has no special effect
c\bco\bom\bmp\bpa\bat\bt3\b32\b2
- +\bo interrupting a command list such as "a ; b ; c" causes
- the execution of the next command in the list (in
- bash-4.0 and later versions, the shell acts as if it re-
- ceived the interrupt, so interrupting one command in a
+ +\bo interrupting a command list such as "a ; b ; c" causes
+ the execution of the next command in the list (in
+ bash-4.0 and later versions, the shell acts as if it re-
+ ceived the interrupt, so interrupting one command in a
list aborts the execution of the entire list)
c\bco\bom\bmp\bpa\bat\bt4\b40\b0
- +\bo the <\b< and >\b> operators to the [\b[[\b[ command do not consider
+ +\bo the <\b< and >\b> operators to the [\b[[\b[ command do not consider
the current locale when comparing strings; they use ASCII
ordering. Bash versions prior to bash-4.1 use ASCII col-
- lation and _\bs_\bt_\br_\bc_\bm_\bp(3); bash-4.1 and later use the current
+ lation and _\bs_\bt_\br_\bc_\bm_\bp(3); bash-4.1 and later use the current
locale's collation sequence and _\bs_\bt_\br_\bc_\bo_\bl_\bl(3).
c\bco\bom\bmp\bpa\bat\bt4\b41\b1
- +\bo in _\bp_\bo_\bs_\bi_\bx mode, t\bti\bim\bme\be may be followed by options and still
+ +\bo in _\bp_\bo_\bs_\bi_\bx mode, t\bti\bim\bme\be may be followed by options and still
be recognized as a reserved word (this is POSIX interpre-
tation 267)
+\bo in _\bp_\bo_\bs_\bi_\bx mode, the parser requires that an even number of
- single quotes occur in the _\bw_\bo_\br_\bd portion of a double-
- quoted parameter expansion and treats them specially, so
- that characters within the single quotes are considered
+ single quotes occur in the _\bw_\bo_\br_\bd portion of a double-
+ quoted parameter expansion and treats them specially, so
+ that characters within the single quotes are considered
quoted (this is POSIX interpretation 221)
c\bco\bom\bmp\bpa\bat\bt4\b42\b2
+\bo the replacement string in double-quoted pattern substitu-
- tion does not undergo quote removal, as it does in ver-
+ tion does not undergo quote removal, as it does in ver-
sions after bash-4.2
- +\bo in posix mode, single quotes are considered special when
- expanding the _\bw_\bo_\br_\bd portion of a double-quoted parameter
- expansion and can be used to quote a closing brace or
- other special character (this is part of POSIX interpre-
- tation 221); in later versions, single quotes are not
+ +\bo in posix mode, single quotes are considered special when
+ expanding the _\bw_\bo_\br_\bd portion of a double-quoted parameter
+ expansion and can be used to quote a closing brace or
+ other special character (this is part of POSIX interpre-
+ tation 221); in later versions, single quotes are not
special within double-quoted word expansions
c\bco\bom\bmp\bpa\bat\bt4\b43\b3
- +\bo the shell does not print a warning message if an attempt
- is made to use a quoted compound assignment as an argu-
- ment to declare (e.g., declare -a foo='(1 2)'). Later
+ +\bo the shell does not print a warning message if an attempt
+ is made to use a quoted compound assignment as an argu-
+ ment to declare (e.g., declare -a foo='(1 2)'). Later
versions warn that this usage is deprecated
- +\bo word expansion errors are considered non-fatal errors
- that cause the current command to fail, even in posix
- mode (the default behavior is to make them fatal errors
+ +\bo word expansion errors are considered non-fatal errors
+ that cause the current command to fail, even in posix
+ mode (the default behavior is to make them fatal errors
that cause the shell to exit)
- +\bo when executing a shell function, the loop state
+ +\bo when executing a shell function, the loop state
(while/until/etc.) is not reset, so b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be in
that function will break or continue loops in the calling
- context. Bash-4.4 and later reset the loop state to pre-
+ context. Bash-4.4 and later reset the loop state to pre-
vent this
c\bco\bom\bmp\bpa\bat\bt4\b44\b4
- +\bo the shell sets up the values used by B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV and
- B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC so they can expand to the shell's positional
+ +\bo the shell sets up the values used by B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV and
+ B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC so they can expand to the shell's positional
parameters even if extended debugging mode is not enabled
- +\bo a subshell inherits loops from its parent context, so
- b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be will cause the subshell to exit.
- Bash-5.0 and later reset the loop state to prevent the
+ +\bo a subshell inherits loops from its parent context, so
+ b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be will cause the subshell to exit.
+ Bash-5.0 and later reset the loop state to prevent the
exit
- +\bo variable assignments preceding builtins like e\bex\bxp\bpo\bor\brt\bt and
+ +\bo variable assignments preceding builtins like e\bex\bxp\bpo\bor\brt\bt and
r\bre\bea\bad\bdo\bon\bnl\bly\by that set attributes continue to affect variables
with the same name in the calling environment even if the
shell is not in posix mode
c\bco\bom\bmp\bpa\bat\bt5\b50\b0
- +\bo Bash-5.1 changed the way $\b$R\bRA\bAN\bND\bDO\bOM\bM is generated to intro-
+ +\bo Bash-5.1 changed the way $\b$R\bRA\bAN\bND\bDO\bOM\bM is generated to intro-
duce slightly more randomness. If the shell compatibility
- level is set to 50 or lower, it reverts to the method
- from bash-5.0 and previous versions, so seeding the ran-
- dom number generator by assigning a value to R\bRA\bAN\bND\bDO\bOM\bM will
+ level is set to 50 or lower, it reverts to the method
+ from bash-5.0 and previous versions, so seeding the ran-
+ dom number generator by assigning a value to R\bRA\bAN\bND\bDO\bOM\bM will
produce the same sequence as in bash-5.0
- +\bo If the command hash table is empty, bash versions prior
- to bash-5.1 printed an informational message to that ef-
- fect, even when producing output that can be reused as
- input. Bash-5.1 suppresses that message when the -\b-l\bl op-
+ +\bo If the command hash table is empty, bash versions prior
+ to bash-5.1 printed an informational message to that ef-
+ fect, even when producing output that can be reused as
+ input. Bash-5.1 suppresses that message when the -\b-l\bl op-
tion is supplied.
c\bco\bom\bmp\bpa\bat\bt5\b51\b1
- +\bo The u\bun\bns\bse\bet\bt builtin treats attempts to unset array sub-
- scripts @\b@ and *\b* differently depending on whether the ar-
- ray is indexed or associative, and differently than in
+ +\bo The u\bun\bns\bse\bet\bt builtin treats attempts to unset array sub-
+ scripts @\b@ and *\b* differently depending on whether the ar-
+ ray is indexed or associative, and differently than in
previous versions.
S\bSE\bEE\bE A\bAL\bLS\bSO\bO
projects / thirdparty / bash.git / commitdiff
