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Diffstat (limited to 'doc/bash.0')
| -rw-r--r-- | doc/bash.0 | 3511 |
1 files changed, 1880 insertions, 1631 deletions
@@ -6,10 +6,10 @@ NNAAMMEE bash - GNU Bourne-Again SHell SSYYNNOOPPSSIISS - bbaasshh [options] [file] + bbaasshh [options] [command_string | file] CCOOPPYYRRIIGGHHTT - Bash is Copyright (C) 1989-2010 by the Free Software Foundation, Inc. + Bash is Copyright (C) 1989-2013 by the Free Software Foundation, Inc. DDEESSCCRRIIPPTTIIOONN BBaasshh is an sshh-compatible command language interpreter that executes @@ -26,77 +26,80 @@ OOPPTTIIOONNSS is invoked. In addition, bbaasshh interprets the following options when it is invoked: - --cc _s_t_r_i_n_g If the --cc option is present, then commands are read from - _s_t_r_i_n_g. If there are arguments after the _s_t_r_i_n_g, they are - assigned to the positional parameters, starting with $$00. + --cc If the --cc option is present, then commands are read from the + first non-option argument _c_o_m_m_a_n_d___s_t_r_i_n_g. If there are argu- + ments after the _c_o_m_m_a_n_d___s_t_r_i_n_g, they are assigned to the + positional parameters, starting with $$00. --ii If the --ii option is present, the shell is _i_n_t_e_r_a_c_t_i_v_e. --ll Make bbaasshh act as if it had been invoked as a login shell (see IINNVVOOCCAATTIIOONN below). - --rr If the --rr option is present, the shell becomes _r_e_s_t_r_i_c_t_e_d + --rr If the --rr option is present, the shell becomes _r_e_s_t_r_i_c_t_e_d (see RREESSTTRRIICCTTEEDD SSHHEELLLL below). - --ss If the --ss option is present, or if no arguments remain after - option processing, then commands are read from the standard - input. This option allows the positional parameters to be + --ss If the --ss option is present, or if no arguments remain after + option processing, then commands are read from the standard + input. This option allows the positional parameters to be set when invoking an interactive shell. - --DD A list of all double-quoted strings preceded by $$ is printed - on the standard output. These are the strings that are sub- + --DD A list of all double-quoted strings preceded by $$ is printed + on the standard output. These are the strings that are sub- ject to language translation when the current locale is not CC - or PPOOSSIIXX. This implies the --nn option; no commands will be + or PPOOSSIIXX. This implies the --nn option; no commands will be executed. [[--++]]OO [[_s_h_o_p_t___o_p_t_i_o_n]] - _s_h_o_p_t___o_p_t_i_o_n is one of the shell options accepted by the - sshhoopptt builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). If + _s_h_o_p_t___o_p_t_i_o_n is one of the shell options accepted by the + sshhoopptt builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). If _s_h_o_p_t___o_p_t_i_o_n is present, --OO sets the value of that option; ++OO - unsets it. If _s_h_o_p_t___o_p_t_i_o_n is not supplied, the names and - values of the shell options accepted by sshhoopptt are printed on - the standard output. If the invocation option is ++OO, the - output is displayed in a format that may be reused as input. - ---- A ---- signals the end of options and disables further option - processing. Any arguments after the ---- are treated as file- + unsets it. If _s_h_o_p_t___o_p_t_i_o_n is not supplied, the names and + values of the shell options accepted by sshhoopptt are printed on + the standard output. If the invocation option is ++OO, the + output is displayed in a format that may be reused as input. + ---- A ---- signals the end of options and disables further option + processing. Any arguments after the ---- are treated as file- names and arguments. An argument of -- is equivalent to ----. - BBaasshh also interprets a number of multi-character options. These - options must appear on the command line before the single-character + BBaasshh also interprets a number of multi-character options. These + options must appear on the command line before the single-character options to be recognized. ----ddeebbuuggggeerr Arrange for the debugger profile to be executed before the shell - starts. Turns on extended debugging mode (see the description + starts. Turns on extended debugging mode (see the description of the eexxttddeebbuugg option to the sshhoopptt builtin below). ----dduummpp--ppoo--ssttrriinnggss - Equivalent to --DD, but the output is in the GNU _g_e_t_t_e_x_t ppoo (por- + Equivalent to --DD, but the output is in the GNU _g_e_t_t_e_x_t ppoo (por- table object) file format. ----dduummpp--ssttrriinnggss Equivalent to --DD. - ----hheellpp Display a usage message on standard output and exit success- + ----hheellpp Display a usage message on standard output and exit success- fully. ----iinniitt--ffiillee _f_i_l_e ----rrccffiillee _f_i_l_e Execute commands from _f_i_l_e instead of the standard personal ini- - tialization file _~_/_._b_a_s_h_r_c if the shell is interactive (see + tialization file _~_/_._b_a_s_h_r_c if the shell is interactive (see IINNVVOOCCAATTIIOONN below). ----llooggiinn Equivalent to --ll. ----nnooeeddiittiinngg - Do not use the GNU rreeaaddlliinnee library to read command lines when + Do not use the GNU rreeaaddlliinnee library to read command lines when the shell is interactive. ----nnoopprrooffiillee - Do not read either the system-wide startup file _/_e_t_c_/_p_r_o_f_i_l_e or - any of the personal initialization files _~_/_._b_a_s_h___p_r_o_f_i_l_e, - _~_/_._b_a_s_h___l_o_g_i_n, or _~_/_._p_r_o_f_i_l_e. By default, bbaasshh reads these - files when it is invoked as a login shell (see IINNVVOOCCAATTIIOONN + Do not read either the system-wide startup file _/_e_t_c_/_p_r_o_f_i_l_e or + any of the personal initialization files _~_/_._b_a_s_h___p_r_o_f_i_l_e, + _~_/_._b_a_s_h___l_o_g_i_n, or _~_/_._p_r_o_f_i_l_e. By default, bbaasshh reads these + files when it is invoked as a login shell (see IINNVVOOCCAATTIIOONN below). ----nnoorrcc Do not read and execute the personal initialization file - _~_/_._b_a_s_h_r_c if the shell is interactive. This option is on by + _~_/_._b_a_s_h_r_c if the shell is interactive. This option is on by default if the shell is invoked as sshh. ----ppoossiixx - Change the behavior of bbaasshh where the default operation differs - from the POSIX standard to match the standard (_p_o_s_i_x _m_o_d_e). + Change the behavior of bbaasshh where the default operation differs + from the POSIX standard to match the standard (_p_o_s_i_x _m_o_d_e). See + SSEEEE AALLSSOO below for a reference to a document that details how + posix mode affects bash's behavior. ----rreessttrriicctteedd The shell becomes restricted (see RREESSTTRRIICCTTEEDD SSHHEELLLL below). @@ -105,113 +108,113 @@ OOPPTTIIOONNSS Equivalent to --vv. ----vveerrssiioonn - Show version information for this instance of bbaasshh on the stan- + Show version information for this instance of bbaasshh on the stan- dard output and exit successfully. AARRGGUUMMEENNTTSS If arguments remain after option processing, and neither the --cc nor the - --ss option has been supplied, the first argument is assumed to be the - name of a file containing shell commands. If bbaasshh is invoked in this - fashion, $$00 is set to the name of the file, and the positional parame- - ters are set to the remaining arguments. BBaasshh reads and executes com- - mands from this file, then exits. BBaasshh's exit status is the exit sta- - tus of the last command executed in the script. If no commands are - executed, the exit status is 0. An attempt is first made to open the + --ss option has been supplied, the first argument is assumed to be the + name of a file containing shell commands. If bbaasshh is invoked in this + fashion, $$00 is set to the name of the file, and the positional parame- + ters are set to the remaining arguments. BBaasshh reads and executes com- + mands from this file, then exits. BBaasshh's exit status is the exit sta- + tus of the last command executed in the script. If no commands are + executed, the exit status is 0. An attempt is first made to open the file in the current directory, and, if no file is found, then the shell searches the directories in PPAATTHH for the script. IINNVVOOCCAATTIIOONN - A _l_o_g_i_n _s_h_e_l_l is one whose first character of argument zero is a --, or + A _l_o_g_i_n _s_h_e_l_l is one whose first character of argument zero is a --, or one started with the ----llooggiinn option. - An _i_n_t_e_r_a_c_t_i_v_e shell is one started without non-option arguments and + An _i_n_t_e_r_a_c_t_i_v_e shell is one started without non-option arguments and without the --cc option whose standard input and error are both connected - to terminals (as determined by _i_s_a_t_t_y(3)), or one started with the --ii - option. PPSS11 is set and $$-- includes ii if bbaasshh is interactive, allowing + to terminals (as determined by _i_s_a_t_t_y(3)), or one started with the --ii + option. PPSS11 is set and $$-- includes ii if bbaasshh is interactive, allowing a shell script or a startup file to test this state. - The following paragraphs describe how bbaasshh executes its startup files. - If any of the files exist but cannot be read, bbaasshh reports an error. - Tildes are expanded in file names as described below under TTiillddee EExxppaann-- + The following paragraphs describe how bbaasshh executes its startup files. + If any of the files exist but cannot be read, bbaasshh reports an error. + Tildes are expanded in filenames as described below under TTiillddee EExxppaann-- ssiioonn in the EEXXPPAANNSSIIOONN section. - When bbaasshh is invoked as an interactive login shell, or as a non-inter- - active shell with the ----llooggiinn option, it first reads and executes com- - mands from the file _/_e_t_c_/_p_r_o_f_i_l_e, if that file exists. After reading + When bbaasshh is invoked as an interactive login shell, or as a non-inter- + active shell with the ----llooggiinn option, it first reads and executes com- + mands from the file _/_e_t_c_/_p_r_o_f_i_l_e, if that file exists. After reading that file, it looks for _~_/_._b_a_s_h___p_r_o_f_i_l_e, _~_/_._b_a_s_h___l_o_g_i_n, and _~_/_._p_r_o_f_i_l_e, - in that order, and reads and executes commands from the first one that - exists and is readable. The ----nnoopprrooffiillee option may be used when the + in that order, and reads and executes commands from the first one that + exists and is readable. The ----nnoopprrooffiillee option may be used when the shell is started to inhibit this behavior. - When a login shell exits, bbaasshh reads and executes commands from the + When a login shell exits, bbaasshh reads and executes commands from the file _~_/_._b_a_s_h___l_o_g_o_u_t, if it exists. - When an interactive shell that is not a login shell is started, bbaasshh - reads and executes commands from _~_/_._b_a_s_h_r_c, if that file exists. This - may be inhibited by using the ----nnoorrcc option. The ----rrccffiillee _f_i_l_e option - will force bbaasshh to read and execute commands from _f_i_l_e instead of + When an interactive shell that is not a login shell is started, bbaasshh + reads and executes commands from _~_/_._b_a_s_h_r_c, if that file exists. This + may be inhibited by using the ----nnoorrcc option. The ----rrccffiillee _f_i_l_e option + will force bbaasshh to read and execute commands from _f_i_l_e instead of _~_/_._b_a_s_h_r_c. - When bbaasshh is started non-interactively, to run a shell script, for + When bbaasshh is started non-interactively, to run a shell script, for example, it looks for the variable BBAASSHH__EENNVV in the environment, expands - its value if it appears there, and uses the expanded value as the name - of a file to read and execute. BBaasshh behaves as if the following com- + its value if it appears there, and uses the expanded value as the name + of a file to read and execute. BBaasshh behaves as if the following com- mand were executed: if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi - but the value of the PPAATTHH variable is not used to search for the file + but the value of the PPAATTHH variable is not used to search for the file- name. - If bbaasshh is invoked with the name sshh, it tries to mimic the startup - behavior of historical versions of sshh as closely as possible, while - conforming to the POSIX standard as well. When invoked as an interac- - tive login shell, or a non-interactive shell with the ----llooggiinn option, - it first attempts to read and execute commands from _/_e_t_c_/_p_r_o_f_i_l_e and - _~_/_._p_r_o_f_i_l_e, in that order. The ----nnoopprrooffiillee option may be used to - inhibit this behavior. When invoked as an interactive shell with the - name sshh, bbaasshh looks for the variable EENNVV, expands its value if it is - defined, and uses the expanded value as the name of a file to read and + If bbaasshh is invoked with the name sshh, it tries to mimic the startup + behavior of historical versions of sshh as closely as possible, while + conforming to the POSIX standard as well. When invoked as an interac- + tive login shell, or a non-interactive shell with the ----llooggiinn option, + it first attempts to read and execute commands from _/_e_t_c_/_p_r_o_f_i_l_e and + _~_/_._p_r_o_f_i_l_e, in that order. The ----nnoopprrooffiillee option may be used to + inhibit this behavior. When invoked as an interactive shell with the + name sshh, bbaasshh looks for the variable EENNVV, expands its value if it is + defined, and uses the expanded value as the name of a file to read and execute. Since a shell invoked as sshh does not attempt to read and exe- - cute commands from any other startup files, the ----rrccffiillee option has no - effect. A non-interactive shell invoked with the name sshh does not - attempt to read any other startup files. When invoked as sshh, bbaasshh + cute commands from any other startup files, the ----rrccffiillee option has no + effect. A non-interactive shell invoked with the name sshh does not + attempt to read any other startup files. When invoked as sshh, bbaasshh enters _p_o_s_i_x mode after the startup files are read. - When bbaasshh is started in _p_o_s_i_x mode, as with the ----ppoossiixx command line + When bbaasshh is started in _p_o_s_i_x mode, as with the ----ppoossiixx command line option, it follows the POSIX standard for startup files. In this mode, - interactive shells expand the EENNVV variable and commands are read and - executed from the file whose name is the expanded value. No other + interactive shells expand the EENNVV variable and commands are read and + executed from the file whose name is the expanded value. No other startup files are read. BBaasshh attempts to determine when it is being run with its standard input connected to a network connection, as when executed by the remote shell - daemon, usually _r_s_h_d, or the secure shell daemon _s_s_h_d. If bbaasshh deter- - mines it is being run in this fashion, it reads and executes commands - from _~_/_._b_a_s_h_r_c, if that file exists and is readable. It will not do - this if invoked as sshh. The ----nnoorrcc option may be used to inhibit this - behavior, and the ----rrccffiillee option may be used to force another file to - be read, but _r_s_h_d does not generally invoke the shell with those - options or allow them to be specified. + daemon, usually _r_s_h_d, or the secure shell daemon _s_s_h_d. If bbaasshh deter- + mines it is being run in this fashion, it reads and executes commands + from _~_/_._b_a_s_h_r_c, if that file exists and is readable. It will not do + this if invoked as sshh. The ----nnoorrcc option may be used to inhibit this + behavior, and the ----rrccffiillee option may be used to force another file to + be read, but neither _r_s_h_d nor _s_s_h_d generally invoke the shell with + those options or allow them to be specified. If the shell is started with the effective user (group) id not equal to the real user (group) id, and the --pp option is not supplied, no startup files are read, shell functions are not inherited from the environment, - the SSHHEELLLLOOPPTTSS, BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they - appear in the environment, are ignored, and the effective user id is - set to the real user id. If the --pp option is supplied at invocation, - the startup behavior is the same, but the effective user id is not + the SSHHEELLLLOOPPTTSS, BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they + appear in the environment, are ignored, and the effective user id is + set to the real user id. If the --pp option is supplied at invocation, + the startup behavior is the same, but the effective user id is not reset. DDEEFFIINNIITTIIOONNSS - The following definitions are used throughout the rest of this docu- + The following definitions are used throughout the rest of this docu- ment. bbllaannkk A space or tab. - wwoorrdd A sequence of characters considered as a single unit by the + wwoorrdd A sequence of characters considered as a single unit by the shell. Also known as a ttookkeenn. - nnaammee A _w_o_r_d consisting only of alphanumeric characters and under- - scores, and beginning with an alphabetic character or an under- + nnaammee A _w_o_r_d consisting only of alphanumeric characters and under- + scores, and beginning with an alphabetic character or an under- score. Also referred to as an iiddeennttiiffiieerr. mmeettaacchhaarraacctteerr - A character that, when unquoted, separates words. One of the + A character that, when unquoted, separates words. One of the following: || && ;; (( )) << >> ssppaaccee ttaabb ccoonnttrrooll ooppeerraattoorr @@ -222,36 +225,37 @@ DDEEFFIINNIITTIIOONNSS RREESSEERRVVEEDD WWOORRDDSS _R_e_s_e_r_v_e_d _w_o_r_d_s are words that have a special meaning to the shell. The following words are recognized as reserved when unquoted and either the - first word of a simple command (see SSHHEELLLL GGRRAAMMMMAARR below) or the third + first word of a simple command (see SSHHEELLLL GGRRAAMMMMAARR below) or the third word of a ccaassee or ffoorr command: - !! ccaassee ddoo ddoonnee eelliiff eellssee eessaacc ffii ffoorr ffuunnccttiioonn iiff iinn sseelleecctt tthheenn uunnttiill - wwhhiillee {{ }} ttiimmee [[[[ ]]]] + !! ccaassee ccoopprroocc ddoo ddoonnee eelliiff eellssee eessaacc ffii ffoorr ffuunnccttiioonn iiff iinn sseelleecctt + tthheenn uunnttiill wwhhiillee {{ }} ttiimmee [[[[ ]]]] SSHHEELLLL GGRRAAMMMMAARR SSiimmppllee CCoommmmaannddss - A _s_i_m_p_l_e _c_o_m_m_a_n_d is a sequence of optional variable assignments fol- - lowed by bbllaannkk-separated words and redirections, and terminated by a + A _s_i_m_p_l_e _c_o_m_m_a_n_d is a sequence of optional variable assignments fol- + lowed by bbllaannkk-separated words and redirections, and terminated by a _c_o_n_t_r_o_l _o_p_e_r_a_t_o_r. The first word specifies the command to be executed, - and is passed as argument zero. The remaining words are passed as + and is passed as argument zero. The remaining words are passed as arguments to the invoked command. - The return value of a _s_i_m_p_l_e _c_o_m_m_a_n_d is its exit status, or 128+_n if + The return value of a _s_i_m_p_l_e _c_o_m_m_a_n_d is its exit status, or 128+_n if the command is terminated by signal _n. PPiippeelliinneess - A _p_i_p_e_l_i_n_e is a sequence of one or more commands separated by one of + A _p_i_p_e_l_i_n_e is a sequence of one or more commands separated by one of the control operators || or ||&&. The format for a pipeline is: [ttiimmee [--pp]] [ ! ] _c_o_m_m_a_n_d [ [|||||&&] _c_o_m_m_a_n_d_2 ... ] - The standard output of _c_o_m_m_a_n_d is connected via a pipe to the standard - input of _c_o_m_m_a_n_d_2. This connection is performed before any redirec- + The standard output of _c_o_m_m_a_n_d is connected via a pipe to the standard + input of _c_o_m_m_a_n_d_2. This connection is performed before any redirec- tions specified by the command (see RREEDDIIRREECCTTIIOONN below). If ||&& is used, - the standard error of _c_o_m_m_a_n_d is connected to _c_o_m_m_a_n_d_2's standard input - through the pipe; it is shorthand for 22>>&&11 ||. This implicit redirect- - ion of the standard error is performed after any redirections specified - by the command. + _c_o_m_m_a_n_d's standard error, in addition to its standard output, is con- + nected to _c_o_m_m_a_n_d_2's standard input through the pipe; it is shorthand + for 22>>&&11 ||. This implicit redirection of the standard error to the + standard output is performed after any redirections specified by the + command. The return status of a pipeline is the exit status of the last command, unless the ppiippeeffaaiill option is enabled. If ppiippeeffaaiill is enabled, the @@ -316,75 +320,84 @@ SSHHEELLLL GGRRAAMMMMAARR the last command executed in the list. CCoommppoouunndd CCoommmmaannddss - A _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d is one of the following: - - (_l_i_s_t) _l_i_s_t is executed in a subshell environment (see CCOOMMMMAANNDD EEXXEECCUU-- - TTIIOONN EENNVVIIRROONNMMEENNTT below). Variable assignments and builtin com- - mands that affect the shell's environment do not remain in - effect after the command completes. The return status is the + A _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d is one of the following. In most cases a _l_i_s_t in a + command's description may be separated from the rest of the command by + one or more newlines, and may be followed by a newline in place of a + semicolon. + + (_l_i_s_t) _l_i_s_t is executed in a subshell environment (see CCOOMMMMAANNDD EEXXEECCUU-- + TTIIOONN EENNVVIIRROONNMMEENNTT below). Variable assignments and builtin com- + mands that affect the shell's environment do not remain in + effect after the command completes. The return status is the exit status of _l_i_s_t. { _l_i_s_t; } - _l_i_s_t is simply executed in the current shell environment. _l_i_s_t - must be terminated with a newline or semicolon. This is known - as a _g_r_o_u_p _c_o_m_m_a_n_d. The return status is the exit status of - _l_i_s_t. Note that unlike the metacharacters (( and )), {{ and }} are + _l_i_s_t is simply executed in the current shell environment. _l_i_s_t + must be terminated with a newline or semicolon. This is known + as a _g_r_o_u_p _c_o_m_m_a_n_d. The return status is the exit status of + _l_i_s_t. Note that unlike the metacharacters (( and )), {{ and }} are _r_e_s_e_r_v_e_d _w_o_r_d_s and must occur where a reserved word is permitted - to be recognized. Since they do not cause a word break, they - must be separated from _l_i_s_t by whitespace or another shell + to be recognized. Since they do not cause a word break, they + must be separated from _l_i_s_t by whitespace or another shell metacharacter. ((_e_x_p_r_e_s_s_i_o_n)) - The _e_x_p_r_e_s_s_i_o_n is evaluated according to the rules described - below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. If the value of the expres- - sion is non-zero, the return status is 0; otherwise the return + The _e_x_p_r_e_s_s_i_o_n is evaluated according to the rules described + below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. If the value of the expres- + sion is non-zero, the return status is 0; otherwise the return status is 1. This is exactly equivalent to lleett ""_e_x_p_r_e_s_s_i_o_n"". [[[[ _e_x_p_r_e_s_s_i_o_n ]]]] - Return a status of 0 or 1 depending on the evaluation of the - conditional expression _e_x_p_r_e_s_s_i_o_n. Expressions are composed of - the primaries described below under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. - Word splitting and pathname expansion are not performed on the - words between the [[[[ and ]]]]; tilde expansion, parameter and - variable expansion, arithmetic expansion, command substitution, - process substitution, and quote removal are performed. Condi- + Return a status of 0 or 1 depending on the evaluation of the + conditional expression _e_x_p_r_e_s_s_i_o_n. Expressions are composed of + the primaries described below under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. + Word splitting and pathname expansion are not performed on the + words between the [[[[ and ]]]]; tilde expansion, parameter and + variable expansion, arithmetic expansion, command substitution, + process substitution, and quote removal are performed. Condi- tional operators such as --ff must be unquoted to be recognized as primaries. - When used with [[[[, the << and >> operators sort lexicographically + When used with [[[[, the << and >> operators sort lexicographically using the current locale. - When the ==== and !!== operators are used, the string to the right + When the ==== and !!== operators are used, the string to the right of the operator is considered a pattern and matched according to - the rules described below under PPaatttteerrnn MMaattcchhiinngg. If the shell - option nnooccaasseemmaattcchh is enabled, the match is performed without - regard to the case of alphabetic characters. The return value - is 0 if the string matches (====) or does not match (!!==) the pat- - tern, and 1 otherwise. Any part of the pattern may be quoted to - force it to be matched as a string. - - An additional binary operator, ==~~, is available, with the same - precedence as ==== and !!==. When it is used, the string to the - right of the operator is considered an extended regular expres- + the rules described below under PPaatttteerrnn MMaattcchhiinngg, as if the eexxtt-- + gglloobb shell option were enabled. The == operator is equivalent to + ====. If the shell option nnooccaasseemmaattcchh is enabled, the match is + performed without regard to the case of alphabetic characters. + The return value is 0 if the string matches (====) or does not + match (!!==) the pattern, and 1 otherwise. Any part of the pat- + tern may be quoted to force the quoted portion to be matched as + a string. + + An additional binary operator, ==~~, is available, with the same + precedence as ==== and !!==. When it is used, the string to the + right of the operator is considered an extended regular expres- sion and matched accordingly (as in _r_e_g_e_x(3)). The return value is 0 if the string matches the pattern, and 1 otherwise. If the - regular expression is syntactically incorrect, the conditional + regular expression is syntactically incorrect, the conditional expression's return value is 2. If the shell option nnooccaasseemmaattcchh is enabled, the match is performed without regard to the case of alphabetic characters. Any part of the pattern may be quoted to - force it to be matched as a string. Substrings matched by - parenthesized subexpressions within the regular expression are - saved in the array variable BBAASSHH__RREEMMAATTCCHH. The element of - BBAASSHH__RREEMMAATTCCHH with index 0 is the portion of the string matching - the entire regular expression. The element of BBAASSHH__RREEMMAATTCCHH with - index _n is the portion of the string matching the _nth parenthe- - sized subexpression. - - Expressions may be combined using the following operators, + force the quoted portion to be matched as a string. Bracket + expressions in regular expressions must be treated carefully, + since normal quoting characters lose their meanings between + brackets. If the pattern is stored in a shell variable, quoting + the variable expansion forces the entire pattern to be matched + as a string. Substrings matched by parenthesized subexpressions + within the regular expression are saved in the array variable + BBAASSHH__RREEMMAATTCCHH. The element of BBAASSHH__RREEMMAATTCCHH with index 0 is the + portion of the string matching the entire regular expression. + The element of BBAASSHH__RREEMMAATTCCHH with index _n is the portion of the + string matching the _nth parenthesized subexpression. + + Expressions may be combined using the following operators, listed in decreasing order of precedence: (( _e_x_p_r_e_s_s_i_o_n )) - Returns the value of _e_x_p_r_e_s_s_i_o_n. This may be used to + Returns the value of _e_x_p_r_e_s_s_i_o_n. This may be used to override the normal precedence of operators. !! _e_x_p_r_e_s_s_i_o_n True if _e_x_p_r_e_s_s_i_o_n is false. @@ -394,115 +407,118 @@ SSHHEELLLL GGRRAAMMMMAARR True if either _e_x_p_r_e_s_s_i_o_n_1 or _e_x_p_r_e_s_s_i_o_n_2 is true. The &&&& and |||| operators do not evaluate _e_x_p_r_e_s_s_i_o_n_2 if the value - of _e_x_p_r_e_s_s_i_o_n_1 is sufficient to determine the return value of + of _e_x_p_r_e_s_s_i_o_n_1 is sufficient to determine the return value of the entire conditional expression. ffoorr _n_a_m_e [ [ iinn [ _w_o_r_d _._._. ] ] ; ] ddoo _l_i_s_t ; ddoonnee The list of words following iinn is expanded, generating a list of items. The variable _n_a_m_e is set to each element of this list in - turn, and _l_i_s_t is executed each time. If the iinn _w_o_r_d is omit- - ted, the ffoorr command executes _l_i_s_t once for each positional + turn, and _l_i_s_t is executed each time. If the iinn _w_o_r_d is omit- + ted, the ffoorr command executes _l_i_s_t once for each positional parameter that is set (see PPAARRAAMMEETTEERRSS below). The return status - is the exit status of the last command that executes. If the + is the exit status of the last command that executes. If the expansion of the items following iinn results in an empty list, no commands are executed, and the return status is 0. ffoorr (( _e_x_p_r_1 ; _e_x_p_r_2 ; _e_x_p_r_3 )) ; ddoo _l_i_s_t ; ddoonnee First, the arithmetic expression _e_x_p_r_1 is evaluated according to - the rules described below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. The - arithmetic expression _e_x_p_r_2 is then evaluated repeatedly until - it evaluates to zero. Each time _e_x_p_r_2 evaluates to a non-zero - value, _l_i_s_t is executed and the arithmetic expression _e_x_p_r_3 is - evaluated. If any expression is omitted, it behaves as if it + the rules described below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. The + arithmetic expression _e_x_p_r_2 is then evaluated repeatedly until + it evaluates to zero. Each time _e_x_p_r_2 evaluates to a non-zero + value, _l_i_s_t is executed and the arithmetic expression _e_x_p_r_3 is + evaluated. If any expression is omitted, it behaves as if it evaluates to 1. The return value is the exit status of the last command in _l_i_s_t that is executed, or false if any of the expres- sions is invalid. sseelleecctt _n_a_m_e [ iinn _w_o_r_d ] ; ddoo _l_i_s_t ; ddoonnee The list of words following iinn is expanded, generating a list of - items. The set of expanded words is printed on the standard - error, each preceded by a number. If the iinn _w_o_r_d is omitted, - the positional parameters are printed (see PPAARRAAMMEETTEERRSS below). - The PPSS33 prompt is then displayed and a line read from the stan- - dard input. If the line consists of a number corresponding to - one of the displayed words, then the value of _n_a_m_e is set to - that word. If the line is empty, the words and prompt are dis- + items. The set of expanded words is printed on the standard + error, each preceded by a number. If the iinn _w_o_r_d is omitted, + the positional parameters are printed (see PPAARRAAMMEETTEERRSS below). + The PPSS33 prompt is then displayed and a line read from the stan- + dard input. If the line consists of a number corresponding to + one of the displayed words, then the value of _n_a_m_e is set to + that word. If the line is empty, the words and prompt are dis- played again. If EOF is read, the command completes. Any other - value read causes _n_a_m_e to be set to null. The line read is - saved in the variable RREEPPLLYY. The _l_i_s_t is executed after each + value read causes _n_a_m_e to be set to null. The line read is + saved in the variable RREEPPLLYY. The _l_i_s_t is executed after each selection until a bbrreeaakk command is executed. The exit status of - sseelleecctt is the exit status of the last command executed in _l_i_s_t, + sseelleecctt is the exit status of the last command executed in _l_i_s_t, or zero if no commands were executed. ccaassee _w_o_r_d iinn [ [(] _p_a_t_t_e_r_n [ || _p_a_t_t_e_r_n ] ... ) _l_i_s_t ;; ] ... eessaacc A ccaassee command first expands _w_o_r_d, and tries to match it against each _p_a_t_t_e_r_n in turn, using the same matching rules as for path- - name expansion (see PPaatthhnnaammee EExxppaannssiioonn below). The _w_o_r_d is - expanded using tilde expansion, parameter and variable expan- - sion, arithmetic substitution, command substitution, process - substitution and quote removal. Each _p_a_t_t_e_r_n examined is + name expansion (see PPaatthhnnaammee EExxppaannssiioonn below). The _w_o_r_d is expanded using tilde expansion, parameter and variable expan- + sion, arithmetic substitution, command substitution, process + substitution and quote removal. Each _p_a_t_t_e_r_n examined is + expanded using tilde expansion, parameter and variable expan- sion, arithmetic substitution, command substitution, and process - substitution. If the shell option nnooccaasseemmaattcchh is enabled, the - match is performed without regard to the case of alphabetic - characters. When a match is found, the corresponding _l_i_s_t is + substitution. If the shell option nnooccaasseemmaattcchh is enabled, the + match is performed without regard to the case of alphabetic + characters. When a match is found, the corresponding _l_i_s_t is executed. If the ;;;; operator is used, no subsequent matches are - attempted after the first pattern match. Using ;;&& in place of - ;;;; causes execution to continue with the _l_i_s_t associated with - the next set of patterns. Using ;;;;&& in place of ;;;; causes the - shell to test the next pattern list in the statement, if any, + attempted after the first pattern match. Using ;;&& in place of + ;;;; causes execution to continue with the _l_i_s_t associated with + the next set of patterns. Using ;;;;&& in place of ;;;; causes the + shell to test the next pattern list in the statement, if any, and execute any associated _l_i_s_t on a successful match. The exit status is zero if no pattern matches. Otherwise, it is the exit status of the last command executed in _l_i_s_t. - iiff _l_i_s_t; tthheenn _l_i_s_t_; [ eelliiff _l_i_s_t; tthheenn _l_i_s_t; ] ... [ eellssee _l_i_s_t; ] ffii - The iiff _l_i_s_t is executed. If its exit status is zero, the tthheenn - _l_i_s_t is executed. Otherwise, each eelliiff _l_i_s_t is executed in - turn, and if its exit status is zero, the corresponding tthheenn + iiff _l_i_s_t; tthheenn _l_i_s_t; [ eelliiff _l_i_s_t; tthheenn _l_i_s_t; ] ... [ eellssee _l_i_s_t; ] ffii + The iiff _l_i_s_t is executed. If its exit status is zero, the tthheenn + _l_i_s_t is executed. Otherwise, each eelliiff _l_i_s_t is executed in + turn, and if its exit status is zero, the corresponding tthheenn _l_i_s_t is executed and the command completes. Otherwise, the eellssee - _l_i_s_t is executed, if present. The exit status is the exit sta- + _l_i_s_t is executed, if present. The exit status is the exit sta- tus of the last command executed, or zero if no condition tested true. wwhhiillee _l_i_s_t_-_1; ddoo _l_i_s_t_-_2; ddoonnee uunnttiill _l_i_s_t_-_1; ddoo _l_i_s_t_-_2; ddoonnee - The wwhhiillee command continuously executes the list _l_i_s_t_-_2 as long + The wwhhiillee command continuously executes the list _l_i_s_t_-_2 as long as the last command in the list _l_i_s_t_-_1 returns an exit status of - zero. The uunnttiill command is identical to the wwhhiillee command, - except that the test is negated; _l_i_s_t_-_2 is executed as long as - the last command in _l_i_s_t_-_1 returns a non-zero exit status. The - exit status of the wwhhiillee and uunnttiill commands is the exit status + zero. The uunnttiill command is identical to the wwhhiillee command, + except that the test is negated; _l_i_s_t_-_2 is executed as long as + the last command in _l_i_s_t_-_1 returns a non-zero exit status. The + exit status of the wwhhiillee and uunnttiill commands is the exit status of the last command executed in _l_i_s_t_-_2, or zero if none was exe- cuted. CCoopprroocceesssseess A _c_o_p_r_o_c_e_s_s is a shell command preceded by the ccoopprroocc reserved word. A - coprocess is executed asynchronously in a subshell, as if the command - had been terminated with the && control operator, with a two-way pipe + coprocess is executed asynchronously in a subshell, as if the command + had been terminated with the && control operator, with a two-way pipe established between the executing shell and the coprocess. The format for a coprocess is: ccoopprroocc [_N_A_M_E] _c_o_m_m_a_n_d [_r_e_d_i_r_e_c_t_i_o_n_s] - This creates a coprocess named _N_A_M_E. If _N_A_M_E is not supplied, the - default name is _C_O_P_R_O_C. _N_A_M_E must not be supplied if _c_o_m_m_a_n_d is a _s_i_m_- + This creates a coprocess named _N_A_M_E. If _N_A_M_E is not supplied, the + default name is CCOOPPRROOCC. _N_A_M_E must not be supplied if _c_o_m_m_a_n_d is a _s_i_m_- _p_l_e _c_o_m_m_a_n_d (see above); otherwise, it is interpreted as the first word - of the simple command. When the coproc is executed, the shell creates - an array variable (see AArrrraayyss below) named _N_A_M_E in the context of the - executing shell. The standard output of _c_o_m_m_a_n_d is connected via a - pipe to a file descriptor in the executing shell, and that file - descriptor is assigned to _N_A_M_E[0]. The standard input of _c_o_m_m_a_n_d is - connected via a pipe to a file descriptor in the executing shell, and - that file descriptor is assigned to _N_A_M_E[1]. This pipe is established - before any redirections specified by the command (see RREEDDIIRREECCTTIIOONN - below). The file descriptors can be utilized as arguments to shell - commands and redirections using standard word expansions. The process - ID of the shell spawned to execute the coprocess is available as the - value of the variable _N_A_M_E_PID. The wwaaiitt builtin command may be used - to wait for the coprocess to terminate. - - The return status of a coprocess is the exit status of _c_o_m_m_a_n_d. + of the simple command. When the coprocess is executed, the shell cre- + ates an array variable (see AArrrraayyss below) named _N_A_M_E in the context of + the executing shell. The standard output of _c_o_m_m_a_n_d is connected via a + pipe to a file descriptor in the executing shell, and that file + descriptor is assigned to _N_A_M_E[0]. The standard input of _c_o_m_m_a_n_d is + connected via a pipe to a file descriptor in the executing shell, and + that file descriptor is assigned to _N_A_M_E[1]. This pipe is established + before any redirections specified by the command (see RREEDDIIRREECCTTIIOONN + below). The file descriptors can be utilized as arguments to shell + commands and redirections using standard word expansions. The file + descriptors are not available in subshells. The process ID of the + shell spawned to execute the coprocess is available as the value of the + variable _N_A_M_E_PID. The wwaaiitt builtin command may be used to wait for + the coprocess to terminate. + + Since the coprocess is created as an asynchronous command, the ccoopprroocc + command always returns success. The return status of a coprocess is + the exit status of _c_o_m_m_a_n_d. SShheellll FFuunnccttiioonn DDeeffiinniittiioonnss A shell function is an object that is called like a simple command and @@ -518,65 +534,66 @@ SSHHEELLLL GGRRAAMMMMAARR That command is usually a _l_i_s_t of commands between { and }, but may be any command listed under CCoommppoouunndd CCoommmmaannddss above. _c_o_m_- _p_o_u_n_d_-_c_o_m_m_a_n_d is executed whenever _n_a_m_e is specified as the name - of a simple command. Any redirections (see RREEDDIIRREECCTTIIOONN below) - specified when a function is defined are performed when the - function is executed. The exit status of a function definition - is zero unless a syntax error occurs or a readonly function with - the same name already exists. When executed, the exit status of - a function is the exit status of the last command executed in - the body. (See FFUUNNCCTTIIOONNSS below.) + of a simple command. When in _p_o_s_i_x _m_o_d_e, _n_a_m_e may not be the + name of one of the POSIX _s_p_e_c_i_a_l _b_u_i_l_t_i_n_s. Any redirections + (see RREEDDIIRREECCTTIIOONN below) specified when a function is defined are + performed when the function is executed. The exit status of a + function definition is zero unless a syntax error occurs or a + readonly function with the same name already exists. When exe- + cuted, the exit status of a function is the exit status of the + last command executed in the body. (See FFUUNNCCTTIIOONNSS below.) CCOOMMMMEENNTTSS In a non-interactive shell, or an interactive shell in which the iinntteerr-- - aaccttiivvee__ccoommmmeennttss option to the sshhoopptt builtin is enabled (see SSHHEELLLL - BBUUIILLTTIINN CCOOMMMMAANNDDSS below), a word beginning with ## causes that word and - all remaining characters on that line to be ignored. An interactive - shell without the iinntteerraaccttiivvee__ccoommmmeennttss option enabled does not allow + aaccttiivvee__ccoommmmeennttss option to the sshhoopptt builtin is enabled (see SSHHEELLLL + BBUUIILLTTIINN CCOOMMMMAANNDDSS below), a word beginning with ## causes that word and + all remaining characters on that line to be ignored. An interactive + shell without the iinntteerraaccttiivvee__ccoommmmeennttss option enabled does not allow comments. The iinntteerraaccttiivvee__ccoommmmeennttss option is on by default in interac- tive shells. QQUUOOTTIINNGG - _Q_u_o_t_i_n_g is used to remove the special meaning of certain characters or - words to the shell. Quoting can be used to disable special treatment + _Q_u_o_t_i_n_g is used to remove the special meaning of certain characters or + words to the shell. Quoting can be used to disable special treatment for special characters, to prevent reserved words from being recognized as such, and to prevent parameter expansion. - Each of the _m_e_t_a_c_h_a_r_a_c_t_e_r_s listed above under DDEEFFIINNIITTIIOONNSS has special + Each of the _m_e_t_a_c_h_a_r_a_c_t_e_r_s listed above under DDEEFFIINNIITTIIOONNSS has special meaning to the shell and must be quoted if it is to represent itself. - When the command history expansion facilities are being used (see HHIISS-- + When the command history expansion facilities are being used (see HHIISS-- TTOORRYY EEXXPPAANNSSIIOONN below), the _h_i_s_t_o_r_y _e_x_p_a_n_s_i_o_n character, usually !!, must be quoted to prevent history expansion. - There are three quoting mechanisms: the _e_s_c_a_p_e _c_h_a_r_a_c_t_e_r, single + There are three quoting mechanisms: the _e_s_c_a_p_e _c_h_a_r_a_c_t_e_r, single quotes, and double quotes. - A non-quoted backslash (\\) is the _e_s_c_a_p_e _c_h_a_r_a_c_t_e_r. It preserves the + A non-quoted backslash (\\) is the _e_s_c_a_p_e _c_h_a_r_a_c_t_e_r. It preserves the literal value of the next character that follows, with the exception of - <newline>. If a \\<newline> pair appears, and the backslash is not - itself quoted, the \\<newline> is treated as a line continuation (that + <newline>. If a \\<newline> pair appears, and the backslash is not + itself quoted, the \\<newline> is treated as a line continuation (that is, it is removed from the input stream and effectively ignored). - Enclosing characters in single quotes preserves the literal value of + Enclosing characters in single quotes preserves the literal value of each character within the quotes. A single quote may not occur between single quotes, even when preceded by a backslash. - Enclosing characters in double quotes preserves the literal value of - all characters within the quotes, with the exception of $$, ``, \\, and, - when history expansion is enabled, !!. The characters $$ and `` retain - their special meaning within double quotes. The backslash retains its - special meaning only when followed by one of the following characters: - $$, ``, "", \\, or <<nneewwlliinnee>>. A double quote may be quoted within double + Enclosing characters in double quotes preserves the literal value of + all characters within the quotes, with the exception of $$, ``, \\, and, + when history expansion is enabled, !!. The characters $$ and `` retain + their special meaning within double quotes. The backslash retains its + special meaning only when followed by one of the following characters: + $$, ``, "", \\, or <<nneewwlliinnee>>. A double quote may be quoted within double quotes by preceding it with a backslash. If enabled, history expansion - will be performed unless an !! appearing in double quotes is escaped + will be performed unless an !! appearing in double quotes is escaped using a backslash. The backslash preceding the !! is not removed. - The special parameters ** and @@ have special meaning when in double + The special parameters ** and @@ have special meaning when in double quotes (see PPAARRAAMMEETTEERRSS below). Words of the form $$'_s_t_r_i_n_g' are treated specially. The word expands to - _s_t_r_i_n_g, with backslash-escaped characters replaced as specified by the - ANSI C standard. Backslash escape sequences, if present, are decoded + _s_t_r_i_n_g, with backslash-escaped characters replaced as specified by the + ANSI C standard. Backslash escape sequences, if present, are decoded as follows: \\aa alert (bell) \\bb backspace @@ -590,112 +607,142 @@ QQUUOOTTIINNGG \\\\ backslash \\'' single quote \\"" double quote - \\_n_n_n the eight-bit character whose value is the octal value + \\_n_n_n the eight-bit character whose value is the octal value _n_n_n (one to three digits) - \\xx_H_H the eight-bit character whose value is the hexadecimal + \\xx_H_H the eight-bit character whose value is the hexadecimal value _H_H (one or two hex digits) - \\uu_H_H_H_H the Unicode (ISO/IEC 10646) character whose value is the + \\uu_H_H_H_H the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value _H_H_H_H (one to four hex digits) \\UU_H_H_H_H_H_H_H_H - the Unicode (ISO/IEC 10646) character whose value is the + the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value _H_H_H_H_H_H_H_H (one to eight hex digits) \\cc_x a control-_x character - The expanded result is single-quoted, as if the dollar sign had not + The expanded result is single-quoted, as if the dollar sign had not been present. A double-quoted string preceded by a dollar sign ($$"_s_t_r_i_n_g") will cause - the string to be translated according to the current locale. If the - current locale is CC or PPOOSSIIXX, the dollar sign is ignored. If the + the string to be translated according to the current locale. If the + current locale is CC or PPOOSSIIXX, the dollar sign is ignored. If the string is translated and replaced, the replacement is double-quoted. PPAARRAAMMEETTEERRSS - A _p_a_r_a_m_e_t_e_r is an entity that stores values. It can be a _n_a_m_e, a num- + A _p_a_r_a_m_e_t_e_r is an entity that stores values. It can be a _n_a_m_e, a num- ber, or one of the special characters listed below under SSppeecciiaall PPaarraamm-- - eetteerrss. A _v_a_r_i_a_b_l_e is a parameter denoted by a _n_a_m_e. A variable has a - _v_a_l_u_e and zero or more _a_t_t_r_i_b_u_t_e_s. Attributes are assigned using the - ddeeccllaarree builtin command (see ddeeccllaarree below in SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS). + eetteerrss. A _v_a_r_i_a_b_l_e is a parameter denoted by a _n_a_m_e. A variable has a + _v_a_l_u_e and zero or more _a_t_t_r_i_b_u_t_e_s. Attributes are assigned using the + ddeeccllaarree builtin command (see ddeeccllaarree below in SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS). A parameter is set if it has been assigned a value. The null string is - a valid value. Once a variable is set, it may be unset only by using + a valid value. Once a variable is set, it may be unset only by using the uunnsseett builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). A _v_a_r_i_a_b_l_e may be assigned to by a statement of the form _n_a_m_e=[_v_a_l_u_e] - If _v_a_l_u_e is not given, the variable is assigned the null string. All - _v_a_l_u_e_s undergo tilde expansion, parameter and variable expansion, com- - mand substitution, arithmetic expansion, and quote removal (see EEXXPPAANN-- + If _v_a_l_u_e is not given, the variable is assigned the null string. All + _v_a_l_u_e_s undergo tilde expansion, parameter and variable expansion, com- + mand substitution, arithmetic expansion, and quote removal (see EEXXPPAANN-- SSIIOONN below). If the variable has its iinntteeggeerr attribute set, then _v_a_l_u_e is evaluated as an arithmetic expression even if the $((...)) expansion - is not used (see AArriitthhmmeettiicc EExxppaannssiioonn below). Word splitting is not - performed, with the exception of ""$$@@"" as explained below under SSppeecciiaall - PPaarraammeetteerrss. Pathname expansion is not performed. Assignment state- - ments may also appear as arguments to the aalliiaass, ddeeccllaarree, ttyyppeesseett, - eexxppoorrtt, rreeaaddoonnllyy, and llooccaall builtin commands. - - In the context where an assignment statement is assigning a value to a + is not used (see AArriitthhmmeettiicc EExxppaannssiioonn below). Word splitting is not + performed, with the exception of ""$$@@"" as explained below under SSppeecciiaall + PPaarraammeetteerrss. Pathname expansion is not performed. Assignment state- + ments may also appear as arguments to the aalliiaass, ddeeccllaarree, ttyyppeesseett, + eexxppoorrtt, rreeaaddoonnllyy, and llooccaall builtin commands. When in _p_o_s_i_x _m_o_d_e, + these builtins may appear in a command after one or more instances of + the ccoommmmaanndd builtin and retain these assignment statement properties. + + In the context where an assignment statement is assigning a value to a shell variable or array index, the += operator can be used to append to or add to the variable's previous value. When += is applied to a vari- - able for which the _i_n_t_e_g_e_r attribute has been set, _v_a_l_u_e is evaluated - as an arithmetic expression and added to the variable's current value, + able for which the _i_n_t_e_g_e_r attribute has been set, _v_a_l_u_e is evaluated + as an arithmetic expression and added to the variable's current value, which is also evaluated. When += is applied to an array variable using - compound assignment (see AArrrraayyss below), the variable's value is not + compound assignment (see AArrrraayyss below), the variable's value is not unset (as it is when using =), and new values are appended to the array - beginning at one greater than the array's maximum index (for indexed + beginning at one greater than the array's maximum index (for indexed arrays) or added as additional key-value pairs in an associative array. - When applied to a string-valued variable, _v_a_l_u_e is expanded and + When applied to a string-valued variable, _v_a_l_u_e is expanded and appended to the variable's value. + A variable can be assigned the _n_a_m_e_r_e_f attribute using the --nn option to + the ddeeccllaarree or llooccaall builtin commands (see the descriptions of ddeeccllaarree + and llooccaall below) to create a _n_a_m_e_r_e_f, or a reference to another vari- + able. This allows variables to be manipulated indirectly. Whenever + the nameref variable is referenced or assigned to, the operation is + actually performed on the variable specified by the nameref variable's + value. A nameref is commonly used within shell functions to refer to a + variable whose name is passed as an argument to the function. For + instance, if a variable name is passed to a shell function as its first + argument, running + declare -n ref=$1 + inside the function creates a nameref variable rreeff whose value is the + variable name passed as the first argument. References and assignments + to rreeff are treated as references and assignments to the variable whose + name was passed as $$11. If the control variable in a ffoorr loop has the + nameref attribute, the list of words can be a list of shell variables, + and a name reference will be established for each word in the list, in + turn, when the loop is executed. Array variables cannot be given the + --nn attribute. However, nameref variables can reference array variables + and subscripted array variables. Namerefs can be unset using the --nn + option to the uunnsseett builtin. Otherwise, if uunnsseett is executed with the + name of a nameref variable as an argument, the variable referenced by + the nameref variable will be unset. + PPoossiittiioonnaall PPaarraammeetteerrss - A _p_o_s_i_t_i_o_n_a_l _p_a_r_a_m_e_t_e_r is a parameter denoted by one or more digits, + A _p_o_s_i_t_i_o_n_a_l _p_a_r_a_m_e_t_e_r is a parameter denoted by one or more digits, other than the single digit 0. Positional parameters are assigned from - the shell's arguments when it is invoked, and may be reassigned using - the sseett builtin command. Positional parameters may not be assigned to - with assignment statements. The positional parameters are temporarily + the shell's arguments when it is invoked, and may be reassigned using + the sseett builtin command. Positional parameters may not be assigned to + with assignment statements. The positional parameters are temporarily replaced when a shell function is executed (see FFUUNNCCTTIIOONNSS below). - When a positional parameter consisting of more than a single digit is + When a positional parameter consisting of more than a single digit is expanded, it must be enclosed in braces (see EEXXPPAANNSSIIOONN below). SSppeecciiaall PPaarraammeetteerrss - The shell treats several parameters specially. These parameters may + The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed. - ** Expands to the positional parameters, starting from one. When - the expansion occurs within double quotes, it expands to a sin- - gle word with the value of each parameter separated by the first - character of the IIFFSS special variable. That is, "$$**" is equiva- - lent to "$$11_c$$22_c......", where _c is the first character of the value - of the IIFFSS variable. If IIFFSS is unset, the parameters are sepa- - rated by spaces. If IIFFSS is null, the parameters are joined - without intervening separators. - @@ Expands to the positional parameters, starting from one. When + ** Expands to the positional parameters, starting from one. When + the expansion is not within double quotes, each positional + parameter expands to a separate word. In contexts where it is + performed, those words are subject to further word splitting and + pathname expansion. When the expansion occurs within double + quotes, it expands to a single word with the value of each + parameter separated by the first character of the IIFFSS special + variable. That is, "$$**" is equivalent to "$$11_c$$22_c......", where _c + is the first character of the value of the IIFFSS variable. If IIFFSS + is unset, the parameters are separated by spaces. If IIFFSS is + null, the parameters are joined without intervening separators. + @@ Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, "$$@@" is equivalent to "$$11" - "$$22" ... If the double-quoted expansion occurs within a word, - the expansion of the first parameter is joined with the begin- - ning part of the original word, and the expansion of the last - parameter is joined with the last part of the original word. - When there are no positional parameters, "$$@@" and $$@@ expand to + "$$22" ... If the double-quoted expansion occurs within a word, + the expansion of the first parameter is joined with the begin- + ning part of the original word, and the expansion of the last + parameter is joined with the last part of the original word. + When there are no positional parameters, "$$@@" and $$@@ expand to nothing (i.e., they are removed). ## Expands to the number of positional parameters in decimal. - ?? Expands to the exit status of the most recently executed fore- + ?? Expands to the exit status of the most recently executed fore- ground pipeline. - -- Expands to the current option flags as specified upon invoca- - tion, by the sseett builtin command, or those set by the shell + -- Expands to the current option flags as specified upon invoca- + tion, by the sseett builtin command, or those set by the shell itself (such as the --ii option). - $$ Expands to the process ID of the shell. In a () subshell, it - expands to the process ID of the current shell, not the sub- + $$ Expands to the process ID of the shell. In a () subshell, it + expands to the process ID of the current shell, not the sub- shell. - !! Expands to the process ID of the most recently executed back- - ground (asynchronous) command. + !! Expands to the process ID of the job most recently placed into + the background, whether executed as an asynchronous command or + using the bbgg builtin (see JJOOBB CCOONNTTRROOLL below). 00 Expands to the name of the shell or shell script. This is set at shell initialization. If bbaasshh is invoked with a file of com- mands, $$00 is set to the name of that file. If bbaasshh is started with the --cc option, then $$00 is set to the first argument after the string to be executed, if one is present. Otherwise, it is - set to the file name used to invoke bbaasshh, as given by argument + set to the filename used to invoke bbaasshh, as given by argument zero. __ At shell startup, set to the absolute pathname used to invoke the shell or shell script being executed as passed in the envi- @@ -709,7 +756,7 @@ PPAARRAAMMEETTEERRSS SShheellll VVaarriiaabblleess The following variables are set by the shell: - BBAASSHH Expands to the full file name used to invoke this instance of + BBAASSHH Expands to the full filename used to invoke this instance of bbaasshh. BBAASSHHOOPPTTSS A colon-separated list of enabled shell options. Each word in @@ -780,214 +827,196 @@ PPAARRAAMMEETTEERRSS defined in the file $${{BBAASSHH__SSOOUURRCCEE[[_$_i]]}} and called from $${{BBAASSHH__SSOOUURRCCEE[[_$_i_+_1]]}}. BBAASSHH__SSUUBBSSHHEELLLL - Incremented by one each time a subshell or subshell environment - is spawned. The initial value is 0. + Incremented by one within each subshell or subshell environment + when the shell begins executing in that environment. The ini- + tial value is 0. BBAASSHH__VVEERRSSIINNFFOO A readonly array variable whose members hold version information - for this instance of bbaasshh. The values assigned to the array + for this instance of bbaasshh. The values assigned to the array members are as follows: - BBAASSHH__VVEERRSSIINNFFOO[[0]] The major version number (the _r_e_l_e_a_s_e). - BBAASSHH__VVEERRSSIINNFFOO[[1]] The minor version number (the _v_e_r_s_i_o_n). + BBAASSHH__VVEERRSSIINNFFOO[[0]] The major version number (the _r_e_l_e_a_s_e). + BBAASSHH__VVEERRSSIINNFFOO[[1]] The minor version number (the _v_e_r_s_i_o_n). BBAASSHH__VVEERRSSIINNFFOO[[2]] The patch level. BBAASSHH__VVEERRSSIINNFFOO[[3]] The build version. BBAASSHH__VVEERRSSIINNFFOO[[4]] The release status (e.g., _b_e_t_a_1). BBAASSHH__VVEERRSSIINNFFOO[[5]] The value of MMAACCHHTTYYPPEE. - BBAASSHH__VVEERRSSIIOONN - Expands to a string describing the version of this instance of + Expands to a string describing the version of this instance of bbaasshh. - CCOOMMPP__CCWWOORRDD - An index into $${{CCOOMMPP__WWOORRDDSS}} of the word containing the current + An index into $${{CCOOMMPP__WWOORRDDSS}} of the word containing the current cursor position. This variable is available only in shell func- - tions invoked by the programmable completion facilities (see + tions invoked by the programmable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). - CCOOMMPP__KKEEYY The key (or final key of a key sequence) used to invoke the cur- rent completion function. - CCOOMMPP__LLIINNEE - The current command line. This variable is available only in - shell functions and external commands invoked by the pro- - grammable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn + The current command line. This variable is available only in + shell functions and external commands invoked by the pro- + grammable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). - CCOOMMPP__PPOOIINNTT - The index of the current cursor position relative to the begin- - ning of the current command. If the current cursor position is + The index of the current cursor position relative to the begin- + ning of the current command. If the current cursor position is at the end of the current command, the value of this variable is - equal to $${{##CCOOMMPP__LLIINNEE}}. This variable is available only in - shell functions and external commands invoked by the pro- - grammable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn + equal to $${{##CCOOMMPP__LLIINNEE}}. This variable is available only in + shell functions and external commands invoked by the pro- + grammable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). - CCOOMMPP__TTYYPPEE - Set to an integer value corresponding to the type of completion - attempted that caused a completion function to be called: _T_A_B, - for normal completion, _?, for listing completions after succes- - sive tabs, _!, for listing alternatives on partial word comple- - tion, _@, to list completions if the word is not unmodified, or - _%, for menu completion. This variable is available only in - shell functions and external commands invoked by the pro- - grammable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn + Set to an integer value corresponding to the type of completion + attempted that caused a completion function to be called: _T_A_B, + for normal completion, _?, for listing completions after succes- + sive tabs, _!, for listing alternatives on partial word comple- + tion, _@, to list completions if the word is not unmodified, or + _%, for menu completion. This variable is available only in + shell functions and external commands invoked by the pro- + grammable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). - CCOOMMPP__WWOORRDDBBRREEAAKKSS - The set of characters that the rreeaaddlliinnee library treats as word - separators when performing word completion. If CCOOMMPP__WWOORRDDBBRREEAAKKSS - is unset, it loses its special properties, even if it is subse- + The set of characters that the rreeaaddlliinnee library treats as word + separators when performing word completion. If CCOOMMPP__WWOORRDDBBRREEAAKKSS + is unset, it loses its special properties, even if it is subse- quently reset. - CCOOMMPP__WWOORRDDSS - An array variable (see AArrrraayyss below) consisting of the individ- - ual words in the current command line. The line is split into - words as rreeaaddlliinnee would split it, using CCOOMMPP__WWOORRDDBBRREEAAKKSS as + An array variable (see AArrrraayyss below) consisting of the individ- + ual words in the current command line. The line is split into + words as rreeaaddlliinnee would split it, using CCOOMMPP__WWOORRDDBBRREEAAKKSS as described above. This variable is available only in shell func- - tions invoked by the programmable completion facilities (see + tions invoked by the programmable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). - - CCOOPPRROOCC An array variable (see AArrrraayyss below) created to hold the file - descriptors for output from and input to an unnamed coprocess + CCOOPPRROOCC An array variable (see AArrrraayyss below) created to hold the file + descriptors for output from and input to an unnamed coprocess (see CCoopprroocceesssseess above). - DDIIRRSSTTAACCKK An array variable (see AArrrraayyss below) containing the current con- - tents of the directory stack. Directories appear in the stack - in the order they are displayed by the ddiirrss builtin. Assigning + tents of the directory stack. Directories appear in the stack + in the order they are displayed by the ddiirrss builtin. Assigning to members of this array variable may be used to modify directo- - ries already in the stack, but the ppuusshhdd and ppooppdd builtins must + ries already in the stack, but the ppuusshhdd and ppooppdd builtins must be used to add and remove directories. Assignment to this vari- - able will not change the current directory. If DDIIRRSSTTAACCKK is - unset, it loses its special properties, even if it is subse- + able will not change the current directory. If DDIIRRSSTTAACCKK is + unset, it loses its special properties, even if it is subse- quently reset. - - EEUUIIDD Expands to the effective user ID of the current user, initial- + EEUUIIDD Expands to the effective user ID of the current user, initial- ized at shell startup. This variable is readonly. - FFUUNNCCNNAAMMEE - An array variable containing the names of all shell functions + An array variable containing the names of all shell functions currently in the execution call stack. The element with index 0 is the name of any currently-executing shell function. The bot- - tom-most element (the one with the highest index) is "main". - This variable exists only when a shell function is executing. - Assignments to FFUUNNCCNNAAMMEE have no effect and return an error sta- - tus. If FFUUNNCCNNAAMMEE is unset, it loses its special properties, + tom-most element (the one with the highest index) is "main". + This variable exists only when a shell function is executing. + Assignments to FFUUNNCCNNAAMMEE have no effect and return an error sta- + tus. If FFUUNNCCNNAAMMEE is unset, it loses its special properties, even if it is subsequently reset. - This variable can be used with BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE. - Each element of FFUUNNCCNNAAMMEE has corresponding elements in - BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE to describe the call stack. For - instance, $${{FFUUNNCCNNAAMMEE[[_$_i]]}} was called from the file - $${{BBAASSHH__SSOOUURRCCEE[[_$_i_+_1]]}} at line number $${{BBAASSHH__LLIINNEENNOO[[_$_i]]}}. The + This variable can be used with BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE. + Each element of FFUUNNCCNNAAMMEE has corresponding elements in + BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE to describe the call stack. For + instance, $${{FFUUNNCCNNAAMMEE[[_$_i]]}} was called from the file + $${{BBAASSHH__SSOOUURRCCEE[[_$_i_+_1]]}} at line number $${{BBAASSHH__LLIINNEENNOO[[_$_i]]}}. The ccaalllleerr builtin displays the current call stack using this infor- mation. - - GGRROOUUPPSS An array variable containing the list of groups of which the - current user is a member. Assignments to GGRROOUUPPSS have no effect - and return an error status. If GGRROOUUPPSS is unset, it loses its + GGRROOUUPPSS An array variable containing the list of groups of which the + current user is a member. Assignments to GGRROOUUPPSS have no effect + and return an error status. If GGRROOUUPPSS is unset, it loses its special properties, even if it is subsequently reset. - HHIISSTTCCMMDD The history number, or index in the history list, of the current - command. If HHIISSTTCCMMDD is unset, it loses its special properties, + command. If HHIISSTTCCMMDD is unset, it loses its special properties, even if it is subsequently reset. - HHOOSSTTNNAAMMEE Automatically set to the name of the current host. - HHOOSSTTTTYYPPEE - Automatically set to a string that uniquely describes the type - of machine on which bbaasshh is executing. The default is system- + Automatically set to a string that uniquely describes the type + of machine on which bbaasshh is executing. The default is system- dependent. - - LLIINNEENNOO Each time this parameter is referenced, the shell substitutes a - decimal number representing the current sequential line number - (starting with 1) within a script or function. When not in a - script or function, the value substituted is not guaranteed to + LLIINNEENNOO Each time this parameter is referenced, the shell substitutes a + decimal number representing the current sequential line number + (starting with 1) within a script or function. When not in a + script or function, the value substituted is not guaranteed to be meaningful. If LLIINNEENNOO is unset, it loses its special proper- ties, even if it is subsequently reset. - MMAACCHHTTYYPPEE - Automatically set to a string that fully describes the system - type on which bbaasshh is executing, in the standard GNU _c_p_u_-_c_o_m_- + Automatically set to a string that fully describes the system + type on which bbaasshh is executing, in the standard GNU _c_p_u_-_c_o_m_- _p_a_n_y_-_s_y_s_t_e_m format. The default is system-dependent. - MMAAPPFFIILLEE - An array variable (see AArrrraayyss below) created to hold the text + An array variable (see AArrrraayyss below) created to hold the text read by the mmaappffiillee builtin when no variable name is supplied. - OOLLDDPPWWDD The previous working directory as set by the ccdd command. - - OOPPTTAARRGG The value of the last option argument processed by the ggeettooppttss + OOPPTTAARRGG The value of the last option argument processed by the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - - OOPPTTIINNDD The index of the next argument to be processed by the ggeettooppttss + OOPPTTIINNDD The index of the next argument to be processed by the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - - OOSSTTYYPPEE Automatically set to a string that describes the operating sys- - tem on which bbaasshh is executing. The default is system-depen- + OOSSTTYYPPEE Automatically set to a string that describes the operating sys- + tem on which bbaasshh is executing. The default is system-depen- dent. - PPIIPPEESSTTAATTUUSS - An array variable (see AArrrraayyss below) containing a list of exit - status values from the processes in the most-recently-executed + An array variable (see AArrrraayyss below) containing a list of exit + status values from the processes in the most-recently-executed foreground pipeline (which may contain only a single command). - - PPPPIIDD The process ID of the shell's parent. This variable is read- + PPPPIIDD The process ID of the shell's parent. This variable is read- only. - PPWWDD The current working directory as set by the ccdd command. - RRAANNDDOOMM Each time this parameter is referenced, a random integer between 0 and 32767 is generated. The sequence of random numbers may be initialized by assigning a value to RRAANNDDOOMM. If RRAANNDDOOMM is unset, - it loses its special properties, even if it is subsequently + it loses its special properties, even if it is subsequently reset. - RREEAADDLLIINNEE__LLIINNEE The contents of the rreeaaddlliinnee line buffer, for use with "bind -x" (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - RREEAADDLLIINNEE__PPOOIINNTT The position of the insertion point in the rreeaaddlliinnee line buffer, for use with "bind -x" (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - - RREEPPLLYY Set to the line of input read by the rreeaadd builtin command when + RREEPPLLYY Set to the line of input read by the rreeaadd builtin command when no arguments are supplied. - SSEECCOONNDDSS - Each time this parameter is referenced, the number of seconds - since shell invocation is returned. If a value is assigned to - SSEECCOONNDDSS, the value returned upon subsequent references is the - number of seconds since the assignment plus the value assigned. + Each time this parameter is referenced, the number of seconds + since shell invocation is returned. If a value is assigned to + SSEECCOONNDDSS, the value returned upon subsequent references is the + number of seconds since the assignment plus the value assigned. If SSEECCOONNDDSS is unset, it loses its special properties, even if it is subsequently reset. - SSHHEELLLLOOPPTTSS - A colon-separated list of enabled shell options. Each word in - the list is a valid argument for the --oo option to the sseett + A colon-separated list of enabled shell options. Each word in + the list is a valid argument for the --oo option to the sseett builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The options - appearing in SSHHEELLLLOOPPTTSS are those reported as _o_n by sseett --oo. If - this variable is in the environment when bbaasshh starts up, each - shell option in the list will be enabled before reading any + appearing in SSHHEELLLLOOPPTTSS are those reported as _o_n by sseett --oo. If + this variable is in the environment when bbaasshh starts up, each + shell option in the list will be enabled before reading any startup files. This variable is read-only. - SSHHLLVVLL Incremented by one each time an instance of bbaasshh is started. - UUIIDD Expands to the user ID of the current user, initialized at shell startup. This variable is readonly. - The following variables are used by the shell. In some cases, bbaasshh + The following variables are used by the shell. In some cases, bbaasshh assigns a default value to a variable; these cases are noted below. + BBAASSHH__CCOOMMPPAATT + The value is used to set the shell's compatibility level. See + the description of the sshhoopptt builtin below under SSHHEELLLL BBUUIILLTTIINN + CCOOMMMMAANNDDSS for a description of the various compatibility levels + and their effects. The value may be a decimal number (e.g., + 4.2) or an integer (e.g., 42) corresponding to the desired com- + patibility level. If BBAASSHH__CCOOMMPPAATT is unset or set to the empty + string, the compatibility level is set to the default for the + current version. If BBAASSHH__CCOOMMPPAATT is set to a value that is not + one of the valid compatibility levels, the shell prints an error + message and sets the compatibility level to the default for the + current version. The valid compatibility levels correspond to + the compatibility options accepted by the sshhoopptt builtin + described below (for example, ccoommppaatt4422 means that 4.2 and 42 are + valid values). The current version is also a valid value. BBAASSHH__EENNVV If this parameter is set when bbaasshh is executing a shell script, its value is interpreted as a filename containing commands to initialize the shell, as in _~_/_._b_a_s_h_r_c. The value of BBAASSHH__EENNVV is subjected to parameter expansion, command substitution, and - arithmetic expansion before being interpreted as a file name. - PPAATTHH is not used to search for the resultant file name. + arithmetic expansion before being interpreted as a filename. + PPAATTHH is not used to search for the resultant filename. BBAASSHH__XXTTRRAACCEEFFDD If set to an integer corresponding to a valid file descriptor, bbaasshh will write the trace output generated when _s_e_t _-_x is @@ -1001,14 +1030,22 @@ PPAARRAAMMEETTEERRSS list of directories in which the shell looks for destination directories specified by the ccdd command. A sample value is ".:~:/usr". + CCHHIILLDD__MMAAXX + Set the number of exited child status values for the shell to + remember. Bash will not allow this value to be decreased below + a POSIX-mandated minimum, and there is a maximum value (cur- + rently 8192) that this may not exceed. The minimum value is + system-dependent. CCOOLLUUMMNNSS Used by the sseelleecctt compound command to determine the terminal - width when printing selection lists. Automatically set upon + width when printing selection lists. Automatically set if the + cchheecckkwwiinnssiizzee option is enabled or in an interactive shell upon receipt of a SSIIGGWWIINNCCHH. CCOOMMPPRREEPPLLYY An array variable from which bbaasshh reads the possible completions - generated by a shell function invoked by the programmable com- - pletion facility (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). + generated by a shell function invoked by the programmable com- + pletion facility (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). Each + array element contains one possible completion. EEMMAACCSS If bbaasshh finds this variable in the environment when the shell starts with value "t", it assumes that the shell is running in an Emacs shell buffer and disables line editing. @@ -1047,15 +1084,17 @@ PPAARRAAMMEETTEERRSS HHIISSTTFFIILLEE The name of the file in which command history is saved (see HHIISS-- TTOORRYY below). The default value is _~_/_._b_a_s_h___h_i_s_t_o_r_y. If unset, - the command history is not saved when an interactive shell - exits. + the command history is not saved when a shell exits. HHIISSTTFFIILLEESSIIZZEE The maximum number of lines contained in the history file. When - this variable is assigned a value, the history file is trun- - cated, if necessary, by removing the oldest entries, to contain - no more than that number of lines. The default value is 500. - The history file is also truncated to this size after writing it - when an interactive shell exits. + this variable is assigned a value, the history file is trun- + cated, if necessary, to contain no more than that number of + lines by removing the oldest entries. The history file is also + truncated to this size after writing it when a shell exits. If + the value is 0, the history file is truncated to zero size. + Non-numeric values and numeric values less than zero inhibit + truncation. The shell sets the default value to the value of + HHIISSTTSSIIZZEE after reading any startup files. HHIISSTTIIGGNNOORREE A colon-separated list of patterns used to decide which command lines should be saved on the history list. Each pattern is @@ -1070,7 +1109,11 @@ PPAARRAAMMEETTEERRSS history regardless of the value of HHIISSTTIIGGNNOORREE. HHIISSTTSSIIZZEE The number of commands to remember in the command history (see - HHIISSTTOORRYY below). The default value is 500. + HHIISSTTOORRYY below). If the value is 0, commands are not saved in + the history list. Numeric values less than zero result in every + command being saved on the history list (there is no limit). + The shell sets the default value to 500 after reading any + startup files. HHIISSTTTTIIMMEEFFOORRMMAATT If this variable is set and not null, its value is used as a format string for _s_t_r_f_t_i_m_e(3) to print the time stamp associated @@ -1127,41 +1170,42 @@ PPAARRAAMMEETTEERRSS This variable determines the locale category used for number formatting. LLIINNEESS Used by the sseelleecctt compound command to determine the column - length for printing selection lists. Automatically set upon + length for printing selection lists. Automatically set if the + cchheecckkwwiinnssiizzee option is enabled or in an interactive shell upon receipt of a SSIIGGWWIINNCCHH. - MMAAIILL If this parameter is set to a file or directory name and the - MMAAIILLPPAATTHH variable is not set, bbaasshh informs the user of the - arrival of mail in the specified file or Maildir-format direc- + MMAAIILL If this parameter is set to a file or directory name and the + MMAAIILLPPAATTHH variable is not set, bbaasshh informs the user of the + arrival of mail in the specified file or Maildir-format direc- tory. MMAAIILLCCHHEECCKK - Specifies how often (in seconds) bbaasshh checks for mail. The - default is 60 seconds. When it is time to check for mail, the - shell does so before displaying the primary prompt. If this - variable is unset, or set to a value that is not a number + Specifies how often (in seconds) bbaasshh checks for mail. The + default is 60 seconds. When it is time to check for mail, the + shell does so before displaying the primary prompt. If this + variable is unset, or set to a value that is not a number greater than or equal to zero, the shell disables mail checking. MMAAIILLPPAATTHH - A colon-separated list of file names to be checked for mail. - The message to be printed when mail arrives in a particular file - may be specified by separating the file name from the message - with a `?'. When used in the text of the message, $$__ expands to - the name of the current mailfile. Example: + A colon-separated list of filenames to be checked for mail. The + message to be printed when mail arrives in a particular file may + be specified by separating the filename from the message with a + `?'. When used in the text of the message, $$__ expands to the + name of the current mailfile. Example: MMAAIILLPPAATTHH='/var/mail/bfox?"You have mail":~/shell-mail?"$_ has mail!"' - BBaasshh supplies a default value for this variable, but the loca- - tion of the user mail files that it uses is system dependent + BBaasshh supplies a default value for this variable, but the loca- + tion of the user mail files that it uses is system dependent (e.g., /var/mail/$$UUSSEERR). OOPPTTEERRRR If set to the value 1, bbaasshh displays error messages generated by - the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - OOPPTTEERRRR is initialized to 1 each time the shell is invoked or a + the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). + OOPPTTEERRRR is initialized to 1 each time the shell is invoked or a shell script is executed. - PPAATTHH The search path for commands. It is a colon-separated list of - directories in which the shell looks for commands (see CCOOMMMMAANNDD - EEXXEECCUUTTIIOONN below). A zero-length (null) directory name in the + PPAATTHH The search path for commands. It is a colon-separated list of + directories in which the shell looks for commands (see CCOOMMMMAANNDD + EEXXEECCUUTTIIOONN below). A zero-length (null) directory name in the value of PPAATTHH indicates the current directory. A null directory - name may appear as two adjacent colons, or as an initial or - trailing colon. The default path is system-dependent, and is - set by the administrator who installs bbaasshh. A common value is - ``/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin''. + name may appear as two adjacent colons, or as an initial or + trailing colon. The default path is system-dependent, and is + set by the administrator who installs bbaasshh. A common value is + ``/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin''. PPOOSSIIXXLLYY__CCOORRRREECCTT If this variable is in the environment when bbaasshh starts, the shell enters _p_o_s_i_x _m_o_d_e before reading the startup files, as if @@ -1216,70 +1260,66 @@ PPAARRAAMMEETTEERRSS the fraction is included. If this variable is not set, bbaasshh acts as if it had the value - $$''\\nnrreeaall\\tt%%33llRR\\nnuusseerr\\tt%%33llUU\\nnssyyss%%33llSS''. If the value is null, no - timing information is displayed. A trailing newline is added + $$''\\nnrreeaall\\tt%%33llRR\\nnuusseerr\\tt%%33llUU\\nnssyyss\\tt%%33llSS''. If the value is null, + no timing information is displayed. A trailing newline is added when the format string is displayed. - TTMMOOUUTT If set to a value greater than zero, TTMMOOUUTT is treated as the default timeout for the rreeaadd builtin. The sseelleecctt command termi- nates if input does not arrive after TTMMOOUUTT seconds when input is coming from a terminal. In an interactive shell, the value is - interpreted as the number of seconds to wait for input after - issuing the primary prompt. BBaasshh terminates after waiting for - that number of seconds if input does not arrive. - - TTMMPPDDIIRR If set, bbaasshh uses its value as the name of a directory in which + interpreted as the number of seconds to wait for a line of input + after issuing the primary prompt. BBaasshh terminates after waiting + for that number of seconds if a complete line of input does not + arrive. + TTMMPPDDIIRR If set, bbaasshh uses its value as the name of a directory in which bbaasshh creates temporary files for the shell's use. - aauuttoo__rreessuummee This variable controls how the shell interacts with the user and - job control. If this variable is set, single word simple com- + job control. If this variable is set, single word simple com- mands without redirections are treated as candidates for resump- tion of an existing stopped job. There is no ambiguity allowed; - if there is more than one job beginning with the string typed, - the job most recently accessed is selected. The _n_a_m_e of a - stopped job, in this context, is the command line used to start - it. If set to the value _e_x_a_c_t, the string supplied must match - the name of a stopped job exactly; if set to _s_u_b_s_t_r_i_n_g, the - string supplied needs to match a substring of the name of a - stopped job. The _s_u_b_s_t_r_i_n_g value provides functionality analo- - gous to the %%?? job identifier (see JJOOBB CCOONNTTRROOLL below). If set - to any other value, the supplied string must be a prefix of a + if there is more than one job beginning with the string typed, + the job most recently accessed is selected. The _n_a_m_e of a + stopped job, in this context, is the command line used to start + it. If set to the value _e_x_a_c_t, the string supplied must match + the name of a stopped job exactly; if set to _s_u_b_s_t_r_i_n_g, the + string supplied needs to match a substring of the name of a + stopped job. The _s_u_b_s_t_r_i_n_g value provides functionality analo- + gous to the %%?? job identifier (see JJOOBB CCOONNTTRROOLL below). If set + to any other value, the supplied string must be a prefix of a stopped job's name; this provides functionality analogous to the %%_s_t_r_i_n_g job identifier. - hhiissttcchhaarrss - The two or three characters which control history expansion and + The two or three characters which control history expansion and tokenization (see HHIISSTTOORRYY EEXXPPAANNSSIIOONN below). The first character - is the _h_i_s_t_o_r_y _e_x_p_a_n_s_i_o_n character, the character which signals - the start of a history expansion, normally `!!'. The second - character is the _q_u_i_c_k _s_u_b_s_t_i_t_u_t_i_o_n character, which is used as - shorthand for re-running the previous command entered, substi- - tuting one string for another in the command. The default is - `^^'. The optional third character is the character which indi- - cates that the remainder of the line is a comment when found as - the first character of a word, normally `##'. The history com- + is the _h_i_s_t_o_r_y _e_x_p_a_n_s_i_o_n character, the character which signals + the start of a history expansion, normally `!!'. The second + character is the _q_u_i_c_k _s_u_b_s_t_i_t_u_t_i_o_n character, which is used as + shorthand for re-running the previous command entered, substi- + tuting one string for another in the command. The default is + `^^'. The optional third character is the character which indi- + cates that the remainder of the line is a comment when found as + the first character of a word, normally `##'. The history com- ment character causes history substitution to be skipped for the - remaining words on the line. It does not necessarily cause the + remaining words on the line. It does not necessarily cause the shell parser to treat the rest of the line as a comment. AArrrraayyss - BBaasshh provides one-dimensional indexed and associative array variables. - Any variable may be used as an indexed array; the ddeeccllaarree builtin will - explicitly declare an array. There is no maximum limit on the size of - an array, nor any requirement that members be indexed or assigned con- - tiguously. Indexed arrays are referenced using integers (including - arithmetic expressions) and are zero-based; associative arrays are - referenced using arbitrary strings. + BBaasshh provides one-dimensional indexed and associative array variables. + Any variable may be used as an indexed array; the ddeeccllaarree builtin will + explicitly declare an array. There is no maximum limit on the size of + an array, nor any requirement that members be indexed or assigned con- + tiguously. Indexed arrays are referenced using integers (including + arithmetic expressions) and are zero-based; associative arrays are + referenced using arbitrary strings. Unless otherwise noted, indexed + array indices must be non-negative integers. An indexed array is created automatically if any variable is assigned to using the syntax _n_a_m_e[_s_u_b_s_c_r_i_p_t]=_v_a_l_u_e. The _s_u_b_s_c_r_i_p_t is treated as - an arithmetic expression that must evaluate to a number. If _s_u_b_s_c_r_i_p_t - evaluates to a number less than zero, it is used as an offset from one - greater than the array's maximum index (so a subcript of -1 refers to - the last element of the array). To explicitly declare an indexed - array, use ddeeccllaarree --aa _n_a_m_e (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). ddeeccllaarree - --aa _n_a_m_e[[_s_u_b_s_c_r_i_p_t]] is also accepted; the _s_u_b_s_c_r_i_p_t is ignored. + an arithmetic expression that must evaluate to a number. To explicitly + declare an indexed array, use ddeeccllaarree --aa _n_a_m_e (see SSHHEELLLL BBUUIILLTTIINN CCOOMM-- + MMAANNDDSS below). ddeeccllaarree --aa _n_a_m_e[[_s_u_b_s_c_r_i_p_t]] is also accepted; the _s_u_b_- + _s_c_r_i_p_t is ignored. Associative arrays are created using ddeeccllaarree --AA _n_a_m_e. @@ -1288,17 +1328,21 @@ PPAARRAAMMEETTEERRSS Arrays are assigned to using compound assignments of the form _n_a_m_e=((value_1 ... value_n)), where each _v_a_l_u_e is of the form [_s_u_b_- - _s_c_r_i_p_t]=_s_t_r_i_n_g. Indexed array assignments do not require the bracket - and subscript. When assigning to indexed arrays, if the optional - brackets and subscript are supplied, that index is assigned to; other- - wise the index of the element assigned is the last index assigned to by - the statement plus one. Indexing starts at zero. + _s_c_r_i_p_t]=_s_t_r_i_n_g. Indexed array assignments do not require anything but + _s_t_r_i_n_g. When assigning to indexed arrays, if the optional brackets and + subscript are supplied, that index is assigned to; otherwise the index + of the element assigned is the last index assigned to by the statement + plus one. Indexing starts at zero. When assigning to an associative array, the subscript is required. This syntax is also accepted by the ddeeccllaarree builtin. Individual array elements may be assigned to using the _n_a_m_e[_s_u_b_s_c_r_i_p_t]=_v_a_l_u_e syntax - introduced above. + introduced above. When assigning to an indexed array, if _n_a_m_e is sub- + scripted by a negative number, that number is interpreted as relative + to one greater than the maximum index of _n_a_m_e, so negative indices + count back from the end of the array, and an index of -1 references the + last element. Any element of an array may be referenced using ${_n_a_m_e[_s_u_b_s_c_r_i_p_t]}. The braces are required to avoid conflicts with pathname expansion. If @@ -1316,36 +1360,50 @@ PPAARRAAMMEETTEERRSS above). ${#_n_a_m_e[_s_u_b_s_c_r_i_p_t]} expands to the length of ${_n_a_m_e[_s_u_b_- _s_c_r_i_p_t]}. If _s_u_b_s_c_r_i_p_t is ** or @@, the expansion is the number of ele- ments in the array. Referencing an array variable without a subscript - is equivalent to referencing the array with a subscript of 0. + is equivalent to referencing the array with a subscript of 0. If the + _s_u_b_s_c_r_i_p_t used to reference an element of an indexed array evaluates to + a number less than zero, it is interpreted as relative to one greater + than the maximum index of the array, so negative indices count back + from the end of the array, and an index of -1 references the last ele- + ment. - An array variable is considered set if a subscript has been assigned a + An array variable is considered set if a subscript has been assigned a value. The null string is a valid value. + It is possible to obtain the keys (indices) of an array as well as the + values. ${!!_n_a_m_e[_@]} and ${!!_n_a_m_e[_*]} expand to the indices assigned in + array variable _n_a_m_e. The treatment when in double quotes is similar to + the expansion of the special parameters _@ and _* within double quotes. + The uunnsseett builtin is used to destroy arrays. uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t] - destroys the array element at index _s_u_b_s_c_r_i_p_t. Care must be taken to - avoid unwanted side effects caused by pathname expansion. uunnsseett _n_a_m_e, - where _n_a_m_e is an array, or uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t], where _s_u_b_s_c_r_i_p_t is ** - or @@, removes the entire array. - - The ddeeccllaarree, llooccaall, and rreeaaddoonnllyy builtins each accept a --aa option to - specify an indexed array and a --AA option to specify an associative - array. The rreeaadd builtin accepts a --aa option to assign a list of words - read from the standard input to an array. The sseett and ddeeccllaarree builtins - display array values in a way that allows them to be reused as assign- - ments. + destroys the array element at index _s_u_b_s_c_r_i_p_t. Negative subscripts to + indexed arrays are interpreted as described above. Care must be taken + to avoid unwanted side effects caused by pathname expansion. uunnsseett + _n_a_m_e, where _n_a_m_e is an array, or uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t], where _s_u_b_s_c_r_i_p_t + is ** or @@, removes the entire array. + + The ddeeccllaarree, llooccaall, and rreeaaddoonnllyy builtins each accept a --aa option to + specify an indexed array and a --AA option to specify an associative + array. If both options are supplied, --AA takes precedence. The rreeaadd + builtin accepts a --aa option to assign a list of words read from the + standard input to an array. The sseett and ddeeccllaarree builtins display array + values in a way that allows them to be reused as assignments. EEXXPPAANNSSIIOONN Expansion is performed on the command line after it has been split into - words. There are seven kinds of expansion performed: _b_r_a_c_e _e_x_p_a_n_s_i_o_n, - _t_i_l_d_e _e_x_p_a_n_s_i_o_n, _p_a_r_a_m_e_t_e_r _a_n_d _v_a_r_i_a_b_l_e _e_x_p_a_n_s_i_o_n, _c_o_m_m_a_n_d _s_u_b_s_t_i_t_u_- + words. There are seven kinds of expansion performed: _b_r_a_c_e _e_x_p_a_n_s_i_o_n, + _t_i_l_d_e _e_x_p_a_n_s_i_o_n, _p_a_r_a_m_e_t_e_r _a_n_d _v_a_r_i_a_b_l_e _e_x_p_a_n_s_i_o_n, _c_o_m_m_a_n_d _s_u_b_s_t_i_t_u_- _t_i_o_n, _a_r_i_t_h_m_e_t_i_c _e_x_p_a_n_s_i_o_n, _w_o_r_d _s_p_l_i_t_t_i_n_g, and _p_a_t_h_n_a_m_e _e_x_p_a_n_s_i_o_n. - The order of expansions is: brace expansion, tilde expansion, parame- - ter, variable and arithmetic expansion and command substitution (done - in a left-to-right fashion), word splitting, and pathname expansion. + The order of expansions is: brace expansion; tilde expansion, parameter + and variable expansion, arithmetic expansion, and command substitution + (done in a left-to-right fashion); word splitting; and pathname expan- + sion. On systems that can support it, there is an additional expansion avail- - able: _p_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n. + able: _p_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n. This is performed at the same time as + tilde, parameter, variable, and arithmetic expansion and command sub- + stitution. Only brace expansion, word splitting, and pathname expansion can change the number of words of the expansion; other expansions expand a single @@ -1374,10 +1432,10 @@ EEXXPPAANNSSIIOONN or _y begins with a zero, the shell attempts to force all generated terms to contain the same number of digits, zero-padding where neces- sary. When characters are supplied, the expression expands to each - character lexicographically between _x and _y, inclusive. Note that both - _x and _y must be of the same type. When the increment is supplied, it - is used as the difference between each term. The default increment is - 1 or -1 as appropriate. + character lexicographically between _x and _y, inclusive, using the + default C locale. Note that both _x and _y must be of the same type. + When the increment is supplied, it is used as the difference between + each term. The default increment is 1 or -1 as appropriate. Brace expansion is performed before any other expansions, and any char- acters special to other expansions are preserved in the result. It is @@ -1435,7 +1493,7 @@ EEXXPPAANNSSIIOONN Each variable assignment is checked for unquoted tilde-prefixes immedi- ately following a :: or the first ==. In these cases, tilde expansion is - also performed. Consequently, one may use file names with tildes in + also performed. Consequently, one may use filenames with tildes in assignments to PPAATTHH, MMAAIILLPPAATTHH, and CCDDPPAATTHH, and the shell assigns the expanded value. @@ -1455,69 +1513,87 @@ EEXXPPAANNSSIIOONN The value of _p_a_r_a_m_e_t_e_r is substituted. The braces are required when _p_a_r_a_m_e_t_e_r is a positional parameter with more than one digit, or when _p_a_r_a_m_e_t_e_r is followed by a character which is not - to be interpreted as part of its name. - - If the first character of _p_a_r_a_m_e_t_e_r is an exclamation point (!!), a - level of variable indirection is introduced. BBaasshh uses the value of - the variable formed from the rest of _p_a_r_a_m_e_t_e_r as the name of the vari- - able; this variable is then expanded and that value is used in the rest - of the substitution, rather than the value of _p_a_r_a_m_e_t_e_r itself. This - is known as _i_n_d_i_r_e_c_t _e_x_p_a_n_s_i_o_n. The exceptions to this are the expan- - sions of ${!!\\ffPPffIIpprreeffiixx**} and ${!!_n_a_m_e[_@]} described below. The excla- - mation point must immediately follow the left brace in order to intro- - duce indirection. + to be interpreted as part of its name. The _p_a_r_a_m_e_t_e_r is a shell + parameter as described above PPAARRAAMMEETTEERRSS) or an array reference + (AArrrraayyss). + + If the first character of _p_a_r_a_m_e_t_e_r is an exclamation point (!!), it + introduces a level of variable indirection. BBaasshh uses the value of the + variable formed from the rest of _p_a_r_a_m_e_t_e_r as the name of the variable; + this variable is then expanded and that value is used in the rest of + the substitution, rather than the value of _p_a_r_a_m_e_t_e_r itself. This is + known as _i_n_d_i_r_e_c_t _e_x_p_a_n_s_i_o_n. The exceptions to this are the expansions + of ${!!_p_r_e_f_i_x**} and ${!!_n_a_m_e[_@]} described below. The exclamation point + must immediately follow the left brace in order to introduce indirec- + tion. In each of the cases below, _w_o_r_d is subject to tilde expansion, parame- ter expansion, command substitution, and arithmetic expansion. When not performing substring expansion, using the forms documented - below, bbaasshh tests for a parameter that is unset or null. Omitting the - colon results in a test only for a parameter that is unset. + below (e.g., ::--), bbaasshh tests for a parameter that is unset or null. + Omitting the colon results in a test only for a parameter that is + unset. ${_p_a_r_a_m_e_t_e_r::--_w_o_r_d} - UUssee DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the expan- - sion of _w_o_r_d is substituted. Otherwise, the value of _p_a_r_a_m_e_t_e_r + UUssee DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the expan- + sion of _w_o_r_d is substituted. Otherwise, the value of _p_a_r_a_m_e_t_e_r is substituted. ${_p_a_r_a_m_e_t_e_r::==_w_o_r_d} - AAssssiiggnn DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the + AAssssiiggnn DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the expansion of _w_o_r_d is assigned to _p_a_r_a_m_e_t_e_r. The value of _p_a_r_a_m_- - _e_t_e_r is then substituted. Positional parameters and special + _e_t_e_r is then substituted. Positional parameters and special parameters may not be assigned to in this way. ${_p_a_r_a_m_e_t_e_r::??_w_o_r_d} - DDiissppllaayy EErrrroorr iiff NNuullll oorr UUnnsseett. If _p_a_r_a_m_e_t_e_r is null or unset, - the expansion of _w_o_r_d (or a message to that effect if _w_o_r_d is - not present) is written to the standard error and the shell, if + DDiissppllaayy EErrrroorr iiff NNuullll oorr UUnnsseett. If _p_a_r_a_m_e_t_e_r is null or unset, + the expansion of _w_o_r_d (or a message to that effect if _w_o_r_d is + not present) is written to the standard error and the shell, if it is not interactive, exits. Otherwise, the value of _p_a_r_a_m_e_t_e_r is substituted. ${_p_a_r_a_m_e_t_e_r::++_w_o_r_d} - UUssee AAlltteerrnnaattee VVaalluuee. If _p_a_r_a_m_e_t_e_r is null or unset, nothing is + UUssee AAlltteerrnnaattee VVaalluuee. If _p_a_r_a_m_e_t_e_r is null or unset, nothing is substituted, otherwise the expansion of _w_o_r_d is substituted. ${_p_a_r_a_m_e_t_e_r::_o_f_f_s_e_t} ${_p_a_r_a_m_e_t_e_r::_o_f_f_s_e_t::_l_e_n_g_t_h} - SSuubbssttrriinngg EExxppaannssiioonn. Expands to up to _l_e_n_g_t_h characters of - _p_a_r_a_m_e_t_e_r starting at the character specified by _o_f_f_s_e_t. If - _l_e_n_g_t_h is omitted, expands to the substring of _p_a_r_a_m_e_t_e_r start- - ing at the character specified by _o_f_f_s_e_t. _l_e_n_g_t_h and _o_f_f_s_e_t are - arithmetic expressions (see AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN below). If - _o_f_f_s_e_t evaluates to a number less than zero, the value is used - as an offset from the end of the value of _p_a_r_a_m_e_t_e_r. If _l_e_n_g_t_h - evaluates to a number less than zero, and _p_a_r_a_m_e_t_e_r is not @@ and - not an indexed or associative array, it is interpreted as an - offset from the end of the value of _p_a_r_a_m_e_t_e_r rather than a num- - ber of characters, and the expansion is the characters between - the two offsets. If _p_a_r_a_m_e_t_e_r is @@, the result is _l_e_n_g_t_h posi- - tional parameters beginning at _o_f_f_s_e_t. If _p_a_r_a_m_e_t_e_r is an - indexed array name subscripted by @ or *, the result is the - _l_e_n_g_t_h members of the array beginning with ${_p_a_r_a_m_e_t_e_r[_o_f_f_s_e_t]}. - A negative _o_f_f_s_e_t is taken relative to one greater than the max- - imum index of the specified array. Substring expansion applied - to an associative array produces undefined results. Note that a - negative offset must be separated from the colon by at least one - space to avoid being confused with the :- expansion. Substring - indexing is zero-based unless the positional parameters are - used, in which case the indexing starts at 1 by default. If - _o_f_f_s_e_t is 0, and the positional parameters are used, $$00 is pre- - fixed to the list. + SSuubbssttrriinngg EExxppaannssiioonn. Expands to up to _l_e_n_g_t_h characters of the + value of _p_a_r_a_m_e_t_e_r starting at the character specified by _o_f_f_- + _s_e_t. If _p_a_r_a_m_e_t_e_r is @@, an indexed array subscripted by @@ or **, + or an associative array name, the results differ as described + below. If _l_e_n_g_t_h is omitted, expands to the substring of the + value of _p_a_r_a_m_e_t_e_r starting at the character specified by _o_f_f_s_e_t + and extending to the end of the value. _l_e_n_g_t_h and _o_f_f_s_e_t are + arithmetic expressions (see AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN below). + + If _o_f_f_s_e_t evaluates to a number less than zero, the value is + used as an offset in characters from the end of the value of + _p_a_r_a_m_e_t_e_r. If _l_e_n_g_t_h evaluates to a number less than zero, it + is interpreted as an offset in characters from the end of the + value of _p_a_r_a_m_e_t_e_r rather than a number of characters, and the + expansion is the characters between _o_f_f_s_e_t and that result. + Note that a negative offset must be separated from the colon by + at least one space to avoid being confused with the ::-- expan- + sion. + + If _p_a_r_a_m_e_t_e_r is @@, the result is _l_e_n_g_t_h positional parameters + beginning at _o_f_f_s_e_t. A negative _o_f_f_s_e_t is taken relative to one + greater than the greatest positional parameter, so an offset of + -1 evaluates to the last positional parameter. It is an expan- + sion error if _l_e_n_g_t_h evaluates to a number less than zero. + + If _p_a_r_a_m_e_t_e_r is an indexed array name subscripted by @ or *, the + result is the _l_e_n_g_t_h members of the array beginning with + ${_p_a_r_a_m_e_t_e_r[_o_f_f_s_e_t]}. A negative _o_f_f_s_e_t is taken relative to + one greater than the maximum index of the specified array. It + is an expansion error if _l_e_n_g_t_h evaluates to a number less than + zero. + + Substring expansion applied to an associative array produces + undefined results. + + Substring indexing is zero-based unless the positional parame- + ters are used, in which case the indexing starts at 1 by + default. If _o_f_f_s_e_t is 0, and the positional parameters are + used, $$00 is prefixed to the list. ${!!_p_r_e_f_i_x**} ${!!_p_r_e_f_i_x@@} @@ -1540,78 +1616,85 @@ EEXXPPAANNSSIIOONN _p_a_r_a_m_e_t_e_r is substituted. If _p_a_r_a_m_e_t_e_r is ** or @@, the value substituted is the number of positional parameters. If _p_a_r_a_m_e_- _t_e_r is an array name subscripted by ** or @@, the value substi- - tuted is the number of elements in the array. + tuted is the number of elements in the array. If _p_a_r_a_m_e_t_e_r is + an indexed array name subscripted by a negative number, that + number is interpreted as relative to one greater than the maxi- + mum index of _p_a_r_a_m_e_t_e_r, so negative indices count back from the + end of the array, and an index of -1 references the last ele- + ment. ${_p_a_r_a_m_e_t_e_r##_w_o_r_d} ${_p_a_r_a_m_e_t_e_r####_w_o_r_d} RReemmoovvee mmaattcchhiinngg pprreeffiixx ppaatttteerrnn. The _w_o_r_d is expanded to produce a pattern just as in pathname expansion. If the pattern matches - the beginning of the value of _p_a_r_a_m_e_t_e_r, then the result of the - expansion is the expanded value of _p_a_r_a_m_e_t_e_r with the shortest - matching pattern (the ``##'' case) or the longest matching pat- - tern (the ``####'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ or **, the - pattern removal operation is applied to each positional parame- + the beginning of the value of _p_a_r_a_m_e_t_e_r, then the result of the + expansion is the expanded value of _p_a_r_a_m_e_t_e_r with the shortest + matching pattern (the ``##'' case) or the longest matching pat- + tern (the ``####'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ or **, the + pattern removal operation is applied to each positional parame- ter in turn, and the expansion is the resultant list. If _p_a_r_a_m_- - _e_t_e_r is an array variable subscripted with @@ or **, the pattern - removal operation is applied to each member of the array in + _e_t_e_r is an array variable subscripted with @@ or **, the pattern + removal operation is applied to each member of the array in turn, and the expansion is the resultant list. ${_p_a_r_a_m_e_t_e_r%%_w_o_r_d} ${_p_a_r_a_m_e_t_e_r%%%%_w_o_r_d} RReemmoovvee mmaattcchhiinngg ssuuffffiixx ppaatttteerrnn. The _w_o_r_d is expanded to produce a pattern just as in pathname expansion. If the pattern matches - a trailing portion of the expanded value of _p_a_r_a_m_e_t_e_r, then the - result of the expansion is the expanded value of _p_a_r_a_m_e_t_e_r with - the shortest matching pattern (the ``%%'' case) or the longest - matching pattern (the ``%%%%'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ - or **, the pattern removal operation is applied to each posi- - tional parameter in turn, and the expansion is the resultant - list. If _p_a_r_a_m_e_t_e_r is an array variable subscripted with @@ or - **, the pattern removal operation is applied to each member of + a trailing portion of the expanded value of _p_a_r_a_m_e_t_e_r, then the + result of the expansion is the expanded value of _p_a_r_a_m_e_t_e_r with + the shortest matching pattern (the ``%%'' case) or the longest + matching pattern (the ``%%%%'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ + or **, the pattern removal operation is applied to each posi- + tional parameter in turn, and the expansion is the resultant + list. If _p_a_r_a_m_e_t_e_r is an array variable subscripted with @@ or + **, the pattern removal operation is applied to each member of the array in turn, and the expansion is the resultant list. ${_p_a_r_a_m_e_t_e_r//_p_a_t_t_e_r_n//_s_t_r_i_n_g} PPaatttteerrnn ssuubbssttiittuuttiioonn. The _p_a_t_t_e_r_n is expanded to produce a pat- - tern just as in pathname expansion. _P_a_r_a_m_e_t_e_r is expanded and - the longest match of _p_a_t_t_e_r_n against its value is replaced with - _s_t_r_i_n_g. If _p_a_t_t_e_r_n begins with //, all matches of _p_a_t_t_e_r_n are - replaced with _s_t_r_i_n_g. Normally only the first match is + tern just as in pathname expansion. _P_a_r_a_m_e_t_e_r is expanded and + the longest match of _p_a_t_t_e_r_n against its value is replaced with + _s_t_r_i_n_g. If _p_a_t_t_e_r_n begins with //, all matches of _p_a_t_t_e_r_n are + replaced with _s_t_r_i_n_g. Normally only the first match is replaced. If _p_a_t_t_e_r_n begins with ##, it must match at the begin- ning of the expanded value of _p_a_r_a_m_e_t_e_r. If _p_a_t_t_e_r_n begins with - %%, it must match at the end of the expanded value of _p_a_r_a_m_e_t_e_r. + %%, it must match at the end of the expanded value of _p_a_r_a_m_e_t_e_r. If _s_t_r_i_n_g is null, matches of _p_a_t_t_e_r_n are deleted and the // fol- lowing _p_a_t_t_e_r_n may be omitted. If _p_a_r_a_m_e_t_e_r is @@ or **, the sub- - stitution operation is applied to each positional parameter in - turn, and the expansion is the resultant list. If _p_a_r_a_m_e_t_e_r is - an array variable subscripted with @@ or **, the substitution - operation is applied to each member of the array in turn, and + stitution operation is applied to each positional parameter in + turn, and the expansion is the resultant list. If _p_a_r_a_m_e_t_e_r is + an array variable subscripted with @@ or **, the substitution + operation is applied to each member of the array in turn, and the expansion is the resultant list. ${_p_a_r_a_m_e_t_e_r^^_p_a_t_t_e_r_n} ${_p_a_r_a_m_e_t_e_r^^^^_p_a_t_t_e_r_n} ${_p_a_r_a_m_e_t_e_r,,_p_a_t_t_e_r_n} ${_p_a_r_a_m_e_t_e_r,,,,_p_a_t_t_e_r_n} - CCaassee mmooddiiffiiccaattiioonn. This expansion modifies the case of alpha- - betic characters in _p_a_r_a_m_e_t_e_r. The _p_a_t_t_e_r_n is expanded to pro- - duce a pattern just as in pathname expansion. The ^^ operator - converts lowercase letters matching _p_a_t_t_e_r_n to uppercase; the ,, - operator converts matching uppercase letters to lowercase. The - ^^^^ and ,,,, expansions convert each matched character in the - expanded value; the ^^ and ,, expansions match and convert only - the first character in the expanded value. If _p_a_t_t_e_r_n is omit- - ted, it is treated like a ??, which matches every character. If - _p_a_r_a_m_e_t_e_r is @@ or **, the case modification operation is applied - to each positional parameter in turn, and the expansion is the - resultant list. If _p_a_r_a_m_e_t_e_r is an array variable subscripted - with @@ or **, the case modification operation is applied to each - member of the array in turn, and the expansion is the resultant - list. + CCaassee mmooddiiffiiccaattiioonn. This expansion modifies the case of alpha- + betic characters in _p_a_r_a_m_e_t_e_r. The _p_a_t_t_e_r_n is expanded to pro- + duce a pattern just as in pathname expansion. Each character in + the expanded value of _p_a_r_a_m_e_t_e_r is tested against _p_a_t_t_e_r_n, and, + if it matches the pattern, its case is converted. The pattern + should not attempt to match more than one character. The ^^ + operator converts lowercase letters matching _p_a_t_t_e_r_n to upper- + case; the ,, operator converts matching uppercase letters to low- + ercase. The ^^^^ and ,,,, expansions convert each matched character + in the expanded value; the ^^ and ,, expansions match and convert + only the first character in the expanded value. If _p_a_t_t_e_r_n is + omitted, it is treated like a ??, which matches every character. + If _p_a_r_a_m_e_t_e_r is @@ or **, the case modification operation is + applied to each positional parameter in turn, and the expansion + is the resultant list. If _p_a_r_a_m_e_t_e_r is an array variable sub- + scripted with @@ or **, the case modification operation is applied + to each member of the array in turn, and the expansion is the + resultant list. CCoommmmaanndd SSuubbssttiittuuttiioonn _C_o_m_m_a_n_d _s_u_b_s_t_i_t_u_t_i_o_n allows the output of a command to replace the com- mand name. There are two forms: - $$((_c_o_m_m_a_n_d)) or ``_c_o_m_m_a_n_d`` @@ -1643,136 +1726,141 @@ EEXXPPAANNSSIIOONN The _e_x_p_r_e_s_s_i_o_n is treated as if it were within double quotes, but a double quote inside the parentheses is not treated specially. All - tokens in the expression undergo parameter expansion, string expansion, - command substitution, and quote removal. Arithmetic expansions may be + tokens in the expression undergo parameter and variable expansion, com- + mand substitution, and quote removal. The result is treated as the + arithmetic expression to be evaluated. Arithmetic expansions may be nested. - The evaluation is performed according to the rules listed below under + The evaluation is performed according to the rules listed below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. If _e_x_p_r_e_s_s_i_o_n is invalid, bbaasshh prints a message indicating failure and no substitution occurs. PPrroocceessss SSuubbssttiittuuttiioonn - _P_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n is supported on systems that support named pipes - (_F_I_F_O_s) or the //ddeevv//ffdd method of naming open files. It takes the form - of <<((_l_i_s_t)) or >>((_l_i_s_t)). The process _l_i_s_t is run with its input or out- + _P_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n is supported on systems that support named pipes + (_F_I_F_O_s) or the //ddeevv//ffdd method of naming open files. It takes the form + of <<((_l_i_s_t)) or >>((_l_i_s_t)). The process _l_i_s_t is run with its input or out- put connected to a _F_I_F_O or some file in //ddeevv//ffdd. The name of this file - is passed as an argument to the current command as the result of the - expansion. If the >>((_l_i_s_t)) form is used, writing to the file will pro- - vide input for _l_i_s_t. If the <<((_l_i_s_t)) form is used, the file passed as + is passed as an argument to the current command as the result of the + expansion. If the >>((_l_i_s_t)) form is used, writing to the file will pro- + vide input for _l_i_s_t. If the <<((_l_i_s_t)) form is used, the file passed as an argument should be read to obtain the output of _l_i_s_t. - When available, process substitution is performed simultaneously with - parameter and variable expansion, command substitution, and arithmetic + When available, process substitution is performed simultaneously with + parameter and variable expansion, command substitution, and arithmetic expansion. WWoorrdd SSpplliittttiinngg - The shell scans the results of parameter expansion, command substitu- - tion, and arithmetic expansion that did not occur within double quotes + The shell scans the results of parameter expansion, command substitu- + tion, and arithmetic expansion that did not occur within double quotes for _w_o_r_d _s_p_l_i_t_t_i_n_g. - The shell treats each character of IIFFSS as a delimiter, and splits the - results of the other expansions into words on these characters. If IIFFSS - is unset, or its value is exactly <<ssppaaccee>><<ttaabb>><<nneewwlliinnee>>, the default, - then sequences of <<ssppaaccee>>, <<ttaabb>>, and <<nneewwlliinnee>> at the beginning and - end of the results of the previous expansions are ignored, and any - sequence of IIFFSS characters not at the beginning or end serves to - delimit words. If IIFFSS has a value other than the default, then - sequences of the whitespace characters ssppaaccee and ttaabb are ignored at the - beginning and end of the word, as long as the whitespace character is - in the value of IIFFSS (an IIFFSS whitespace character). Any character in - IIFFSS that is not IIFFSS whitespace, along with any adjacent IIFFSS whitespace - characters, delimits a field. A sequence of IIFFSS whitespace characters - is also treated as a delimiter. If the value of IIFFSS is null, no word - splitting occurs. - - Explicit null arguments ("""" or '''') are retained. Unquoted implicit + The shell treats each character of IIFFSS as a delimiter, and splits the + results of the other expansions into words using these characters as + field terminators. If IIFFSS is unset, or its value is exactly + <<ssppaaccee>><<ttaabb>><<nneewwlliinnee>>, the default, then sequences of <<ssppaaccee>>, <<ttaabb>>, + and <<nneewwlliinnee>> at the beginning and end of the results of the previous + expansions are ignored, and any sequence of IIFFSS characters not at the + beginning or end serves to delimit words. If IIFFSS has a value other + than the default, then sequences of the whitespace characters ssppaaccee and + ttaabb are ignored at the beginning and end of the word, as long as the + whitespace character is in the value of IIFFSS (an IIFFSS whitespace charac- + ter). Any character in IIFFSS that is not IIFFSS whitespace, along with any + adjacent IIFFSS whitespace characters, delimits a field. A sequence of + IIFFSS whitespace characters is also treated as a delimiter. If the value + of IIFFSS is null, no word splitting occurs. + + Explicit null arguments ("""" or '''') are retained. Unquoted implicit null arguments, resulting from the expansion of parameters that have no - values, are removed. If a parameter with no value is expanded within + values, are removed. If a parameter with no value is expanded within double quotes, a null argument results and is retained. Note that if no expansion occurs, no splitting is performed. PPaatthhnnaammee EExxppaannssiioonn - After word splitting, unless the --ff option has been set, bbaasshh scans - each word for the characters **, ??, and [[. If one of these characters - appears, then the word is regarded as a _p_a_t_t_e_r_n, and replaced with an - alphabetically sorted list of file names matching the pattern. If no - matching file names are found, and the shell option nnuullllgglloobb is not - enabled, the word is left unchanged. If the nnuullllgglloobb option is set, - and no matches are found, the word is removed. If the ffaaiillgglloobb shell - option is set, and no matches are found, an error message is printed - and the command is not executed. If the shell option nnooccaasseegglloobb is - enabled, the match is performed without regard to the case of alpha- - betic characters. When a pattern is used for pathname expansion, the - character ````..'''' at the start of a name or immediately following a - slash must be matched explicitly, unless the shell option ddoottgglloobb is - set. When matching a pathname, the slash character must always be - matched explicitly. In other cases, the ````..'''' character is not - treated specially. See the description of sshhoopptt below under SSHHEELLLL - BBUUIILLTTIINN CCOOMMMMAANNDDSS for a description of the nnooccaasseegglloobb, nnuullllgglloobb, ffaaiill-- - gglloobb, and ddoottgglloobb shell options. - - The GGLLOOBBIIGGNNOORREE shell variable may be used to restrict the set of file - names matching a _p_a_t_t_e_r_n. If GGLLOOBBIIGGNNOORREE is set, each matching file - name that also matches one of the patterns in GGLLOOBBIIGGNNOORREE is removed - from the list of matches. The file names ````..'''' and ````....'''' are always - ignored when GGLLOOBBIIGGNNOORREE is set and not null. However, setting GGLLOOBBIIGG-- - NNOORREE to a non-null value has the effect of enabling the ddoottgglloobb shell - option, so all other file names beginning with a ````..'''' will match. To - get the old behavior of ignoring file names beginning with a ````..'''', - make ````..**'''' one of the patterns in GGLLOOBBIIGGNNOORREE. The ddoottgglloobb option is - disabled when GGLLOOBBIIGGNNOORREE is unset. + After word splitting, unless the --ff option has been set, bbaasshh scans + each word for the characters **, ??, and [[. If one of these characters + appears, then the word is regarded as a _p_a_t_t_e_r_n, and replaced with an + alphabetically sorted list of filenames matching the pattern (see PPaatt-- + tteerrnn MMaattcchhiinngg below). If no matching filenames are found, and the + shell option nnuullllgglloobb is not enabled, the word is left unchanged. If + the nnuullllgglloobb option is set, and no matches are found, the word is + removed. If the ffaaiillgglloobb shell option is set, and no matches are + found, an error message is printed and the command is not executed. If + the shell option nnooccaasseegglloobb is enabled, the match is performed without + regard to the case of alphabetic characters. When a pattern is used + for pathname expansion, the character ````..'''' at the start of a name or + immediately following a slash must be matched explicitly, unless the + shell option ddoottgglloobb is set. When matching a pathname, the slash char- + acter must always be matched explicitly. In other cases, the ````..'''' + character is not treated specially. See the description of sshhoopptt below + under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS for a description of the nnooccaasseegglloobb, nnuullll-- + gglloobb, ffaaiillgglloobb, and ddoottgglloobb shell options. + + The GGLLOOBBIIGGNNOORREE shell variable may be used to restrict the set of file- + names matching a _p_a_t_t_e_r_n. If GGLLOOBBIIGGNNOORREE is set, each matching filename + that also matches one of the patterns in GGLLOOBBIIGGNNOORREE is removed from the + list of matches. The filenames ````..'''' and ````....'''' are always ignored + when GGLLOOBBIIGGNNOORREE is set and not null. However, setting GGLLOOBBIIGGNNOORREE to a + non-null value has the effect of enabling the ddoottgglloobb shell option, so + all other filenames beginning with a ````..'''' will match. To get the old + behavior of ignoring filenames beginning with a ````..'''', make ````..**'''' one + of the patterns in GGLLOOBBIIGGNNOORREE. The ddoottgglloobb option is disabled when + GGLLOOBBIIGGNNOORREE is unset. PPaatttteerrnn MMaattcchhiinngg Any character that appears in a pattern, other than the special pattern - characters described below, matches itself. The NUL character may not - occur in a pattern. A backslash escapes the following character; the - escaping backslash is discarded when matching. The special pattern + characters described below, matches itself. The NUL character may not + occur in a pattern. A backslash escapes the following character; the + escaping backslash is discarded when matching. The special pattern characters must be quoted if they are to be matched literally. The special pattern characters have the following meanings: - ** Matches any string, including the null string. When the - gglloobbssttaarr shell option is enabled, and ** is used in a - pathname expansion context, two adjacent **s used as a - single pattern will match all files and zero or more - directories and subdirectories. If followed by a //, two - adjacent **s will match only directories and subdirecto- + ** Matches any string, including the null string. When the + gglloobbssttaarr shell option is enabled, and ** is used in a + pathname expansion context, two adjacent **s used as a + single pattern will match all files and zero or more + directories and subdirectories. If followed by a //, two + adjacent **s will match only directories and subdirecto- ries. ?? Matches any single character. - [[......]] Matches any one of the enclosed characters. A pair of - characters separated by a hyphen denotes a _r_a_n_g_e _e_x_p_r_e_s_- - _s_i_o_n; any character that sorts between those two charac- - ters, inclusive, using the current locale's collating - sequence and character set, is matched. If the first + [[......]] Matches any one of the enclosed characters. A pair of + characters separated by a hyphen denotes a _r_a_n_g_e _e_x_p_r_e_s_- + _s_i_o_n; any character that falls between those two charac- + ters, inclusive, using the current locale's collating + sequence and character set, is matched. If the first character following the [[ is a !! or a ^^ then any charac- - ter not enclosed is matched. The sorting order of char- - acters in range expressions is determined by the current - locale and the value of the LLCC__CCOOLLLLAATTEE shell variable, if - set. A -- may be matched by including it as the first or - last character in the set. A ]] may be matched by includ- - ing it as the first character in the set. - - Within [[ and ]], _c_h_a_r_a_c_t_e_r _c_l_a_s_s_e_s can be specified using + ter not enclosed is matched. The sorting order of char- + acters in range expressions is determined by the current + locale and the values of the LLCC__CCOOLLLLAATTEE or LLCC__AALLLL shell + variables, if set. To obtain the traditional interpreta- + tion of range expressions, where [[aa--dd]] is equivalent to + [[aabbccdd]], set value of the LLCC__AALLLL shell variable to CC, or + enable the gglloobbaasscciiiirraannggeess shell option. A -- may be + matched by including it as the first or last character in + the set. A ]] may be matched by including it as the first + character in the set. + + Within [[ and ]], _c_h_a_r_a_c_t_e_r _c_l_a_s_s_e_s can be specified using the syntax [[::_c_l_a_s_s::]], where _c_l_a_s_s is one of the following classes defined in the POSIX standard: - aallnnuumm aallpphhaa aasscciiii bbllaannkk ccnnttrrll ddiiggiitt ggrraapphh lloowweerr pprriinntt + aallnnuumm aallpphhaa aasscciiii bbllaannkk ccnnttrrll ddiiggiitt ggrraapphh lloowweerr pprriinntt ppuunncctt ssppaaccee uuppppeerr wwoorrdd xxddiiggiitt A character class matches any character belonging to that class. The wwoorrdd character class matches letters, digits, and the character _. - Within [[ and ]], an _e_q_u_i_v_a_l_e_n_c_e _c_l_a_s_s can be specified + Within [[ and ]], an _e_q_u_i_v_a_l_e_n_c_e _c_l_a_s_s can be specified using the syntax [[==_c==]], which matches all characters with - the same collation weight (as defined by the current + the same collation weight (as defined by the current locale) as the character _c. Within [[ and ]], the syntax [[.._s_y_m_b_o_l..]] matches the collat- ing symbol _s_y_m_b_o_l. If the eexxttgglloobb shell option is enabled using the sshhoopptt builtin, several - extended pattern matching operators are recognized. In the following + extended pattern matching operators are recognized. In the following description, a _p_a_t_t_e_r_n_-_l_i_s_t is a list of one or more patterns separated by a ||. Composite patterns may be formed using one or more of the fol- lowing sub-patterns: @@ -1790,23 +1878,26 @@ EEXXPPAANNSSIIOONN QQuuoottee RReemmoovvaall After the preceding expansions, all unquoted occurrences of the charac- - ters \\, '', and "" that did not result from one of the above expansions + ters \\, '', and "" that did not result from one of the above expansions are removed. RREEDDIIRREECCTTIIOONN - Before a command is executed, its input and output may be _r_e_d_i_r_e_c_t_e_d - using a special notation interpreted by the shell. Redirection may - also be used to open and close files for the current shell execution - environment. The following redirection operators may precede or appear - anywhere within a _s_i_m_p_l_e _c_o_m_m_a_n_d or may follow a _c_o_m_m_a_n_d. Redirections - are processed in the order they appear, from left to right. + Before a command is executed, its input and output may be _r_e_d_i_r_e_c_t_e_d + using a special notation interpreted by the shell. Redirection allows + commands' file handles to be duplicated, opened, closed, made to refer + to different files, and can change the files the command reads from and + writes to. Redirection may also be used to modify file handles in the + current shell execution environment. The following redirection opera- + tors may precede or appear anywhere within a _s_i_m_p_l_e _c_o_m_m_a_n_d or may fol- + low a _c_o_m_m_a_n_d. Redirections are processed in the order they appear, + from left to right. Each redirection that may be preceded by a file descriptor number may instead be preceded by a word of the form {_v_a_r_n_a_m_e}. In this case, for each redirection operator except >&- and <&-, the shell will allocate a - file descriptor greater than 10 and assign it to _v_a_r_n_a_m_e. If >&- or - <&- is preceded by {_v_a_r_n_a_m_e}, the value of _v_a_r_n_a_m_e defines the file - descriptor to close. + file descriptor greater than or equal to 10 and assign it to _v_a_r_n_a_m_e. + If >&- or <&- is preceded by {_v_a_r_n_a_m_e}, the value of _v_a_r_n_a_m_e defines + the file descriptor to close. In the following descriptions, if the file descriptor number is omit- ted, and the first character of the redirection operator is <<, the re- @@ -1816,29 +1907,29 @@ RREEDDIIRREECCTTIIOONN The word following the redirection operator in the following descrip- tions, unless otherwise noted, is subjected to brace expansion, tilde - expansion, parameter expansion, command substitution, arithmetic expan- - sion, quote removal, pathname expansion, and word splitting. If it - expands to more than one word, bbaasshh reports an error. + expansion, parameter and variable expansion, command substitution, + arithmetic expansion, quote removal, pathname expansion, and word + splitting. If it expands to more than one word, bbaasshh reports an error. - Note that the order of redirections is significant. For example, the + Note that the order of redirections is significant. For example, the command ls >> dirlist 2>>&&1 - directs both standard output and standard error to the file _d_i_r_l_i_s_t, + directs both standard output and standard error to the file _d_i_r_l_i_s_t, while the command ls 2>>&&1 >> dirlist - directs only the standard output to file _d_i_r_l_i_s_t, because the standard - error was duplicated from the standard output before the standard out- + directs only the standard output to file _d_i_r_l_i_s_t, because the standard + error was duplicated from the standard output before the standard out- put was redirected to _d_i_r_l_i_s_t. BBaasshh handles several filenames specially when they are used in redirec- tions, as described in the following table: //ddeevv//ffdd//_f_d - If _f_d is a valid integer, file descriptor _f_d is dupli- + If _f_d is a valid integer, file descriptor _f_d is dupli- cated. //ddeevv//ssttddiinn File descriptor 0 is duplicated. @@ -1848,22 +1939,22 @@ RREEDDIIRREECCTTIIOONN File descriptor 2 is duplicated. //ddeevv//ttccpp//_h_o_s_t//_p_o_r_t If _h_o_s_t is a valid hostname or Internet address, and _p_o_r_t - is an integer port number or service name, bbaasshh attempts - to open a TCP connection to the corresponding socket. + is an integer port number or service name, bbaasshh attempts + to open the corresponding TCP socket. //ddeevv//uuddpp//_h_o_s_t//_p_o_r_t If _h_o_s_t is a valid hostname or Internet address, and _p_o_r_t - is an integer port number or service name, bbaasshh attempts - to open a UDP connection to the corresponding socket. + is an integer port number or service name, bbaasshh attempts + to open the corresponding UDP socket. A failure to open or create a file causes the redirection to fail. - Redirections using file descriptors greater than 9 should be used with - care, as they may conflict with file descriptors the shell uses inter- + Redirections using file descriptors greater than 9 should be used with + care, as they may conflict with file descriptors the shell uses inter- nally. RReeddiirreeccttiinngg IInnppuutt Redirection of input causes the file whose name results from the expan- - sion of _w_o_r_d to be opened for reading on file descriptor _n, or the + sion of _w_o_r_d to be opened for reading on file descriptor _n, or the standard input (file descriptor 0) if _n is not specified. The general format for redirecting input is: @@ -1871,27 +1962,27 @@ RREEDDIIRREECCTTIIOONN [_n]<<_w_o_r_d RReeddiirreeccttiinngg OOuuttppuutt - Redirection of output causes the file whose name results from the + Redirection of output causes the file whose name results from the expansion of _w_o_r_d to be opened for writing on file descriptor _n, or the standard output (file descriptor 1) if _n is not specified. If the file - does not exist it is created; if it does exist it is truncated to zero + does not exist it is created; if it does exist it is truncated to zero size. The general format for redirecting output is: [_n]>>_w_o_r_d - If the redirection operator is >>, and the nnoocclloobbbbeerr option to the sseett - builtin has been enabled, the redirection will fail if the file whose - name results from the expansion of _w_o_r_d exists and is a regular file. + If the redirection operator is >>, and the nnoocclloobbbbeerr option to the sseett + builtin has been enabled, the redirection will fail if the file whose + name results from the expansion of _w_o_r_d exists and is a regular file. If the redirection operator is >>||, or the redirection operator is >> and the nnoocclloobbbbeerr option to the sseett builtin command is not enabled, the re- direction is attempted even if the file named by _w_o_r_d exists. AAppppeennddiinngg RReeddiirreecctteedd OOuuttppuutt - Redirection of output in this fashion causes the file whose name - results from the expansion of _w_o_r_d to be opened for appending on file - descriptor _n, or the standard output (file descriptor 1) if _n is not + Redirection of output in this fashion causes the file whose name + results from the expansion of _w_o_r_d to be opened for appending on file + descriptor _n, or the standard output (file descriptor 1) if _n is not specified. If the file does not exist it is created. The general format for appending output is: @@ -1900,11 +1991,11 @@ RREEDDIIRREECCTTIIOONN RReeddiirreeccttiinngg SSttaannddaarrdd OOuuttppuutt aanndd SSttaannddaarrdd EErrrroorr - This construct allows both the standard output (file descriptor 1) and - the standard error output (file descriptor 2) to be redirected to the + This construct allows both the standard output (file descriptor 1) and + the standard error output (file descriptor 2) to be redirected to the file whose name is the expansion of _w_o_r_d. - There are two formats for redirecting standard output and standard + There are two formats for redirecting standard output and standard error: &&>>_w_o_r_d @@ -1916,10 +2007,13 @@ RREEDDIIRREECCTTIIOONN >>_w_o_r_d 2>>&&1 + When using the second form, _w_o_r_d may not expand to a number or --. If + it does, other redirection operators apply (see DDuupplliiccaattiinngg FFiillee + DDeessccrriippttoorrss below) for compatibility reasons. AAppppeennddiinngg SSttaannddaarrdd OOuuttppuutt aanndd SSttaannddaarrdd EErrrroorr - This construct allows both the standard output (file descriptor 1) and - the standard error output (file descriptor 2) to be appended to the + This construct allows both the standard output (file descriptor 1) and + the standard error output (file descriptor 2) to be appended to the file whose name is the expansion of _w_o_r_d. The format for appending standard output and standard error is: @@ -1930,10 +2024,12 @@ RREEDDIIRREECCTTIIOONN >>>>_w_o_r_d 2>>&&1 + (see DDuupplliiccaattiinngg FFiillee DDeessccrriippttoorrss below). + HHeerree DDooccuummeennttss - This type of redirection instructs the shell to read input from the + This type of redirection instructs the shell to read input from the current source until a line containing only _d_e_l_i_m_i_t_e_r (with no trailing - blanks) is seen. All of the lines read up to that point are then used + blanks) is seen. All of the lines read up to that point are then used as the standard input for a command. The format of here-documents is: @@ -1942,18 +2038,18 @@ RREEDDIIRREECCTTIIOONN _h_e_r_e_-_d_o_c_u_m_e_n_t _d_e_l_i_m_i_t_e_r - No parameter expansion, command substitution, arithmetic expansion, or - pathname expansion is performed on _w_o_r_d. If any characters in _w_o_r_d are - quoted, the _d_e_l_i_m_i_t_e_r is the result of quote removal on _w_o_r_d, and the - lines in the here-document are not expanded. If _w_o_r_d is unquoted, all - lines of the here-document are subjected to parameter expansion, com- - mand substitution, and arithmetic expansion. In the latter case, the - character sequence \\<<nneewwlliinnee>> is ignored, and \\ must be used to quote - the characters \\, $$, and ``. + No parameter and variable expansion, command substitution, arithmetic + expansion, or pathname expansion is performed on _w_o_r_d. If any charac- + ters in _w_o_r_d are quoted, the _d_e_l_i_m_i_t_e_r is the result of quote removal + on _w_o_r_d, and the lines in the here-document are not expanded. If _w_o_r_d + is unquoted, all lines of the here-document are subjected to parameter + expansion, command substitution, and arithmetic expansion, the charac- + ter sequence \\<<nneewwlliinnee>> is ignored, and \\ must be used to quote the + characters \\, $$, and ``. If the redirection operator is <<<<--, then all leading tab characters are - stripped from input lines and the line containing _d_e_l_i_m_i_t_e_r. This - allows here-documents within shell scripts to be indented in a natural + stripped from input lines and the line containing _d_e_l_i_m_i_t_e_r. This + allows here-documents within shell scripts to be indented in a natural fashion. HHeerree SSttrriinnggss @@ -1961,7 +2057,11 @@ RREEDDIIRREECCTTIIOONN <<<<<<_w_o_r_d - The _w_o_r_d is expanded and supplied to the command on its standard input. + The _w_o_r_d undergoes brace expansion, tilde expansion, parameter and + variable expansion, command substitution, arithmetic expansion, and + quote removal. Pathname expansion and word splitting are not per- + formed. The result is supplied as a single string to the command on + its standard input. DDuupplliiccaattiinngg FFiillee DDeessccrriippttoorrss The redirection operator @@ -1982,16 +2082,17 @@ RREEDDIIRREECCTTIIOONN is used similarly to duplicate output file descriptors. If _n is not specified, the standard output (file descriptor 1) is used. If the digits in _w_o_r_d do not specify a file descriptor open for output, a re- - direction error occurs. As a special case, if _n is omitted, and _w_o_r_d - does not expand to one or more digits, the standard output and standard - error are redirected as described previously. + direction error occurs. If _w_o_r_d evaluates to --, file descriptor _n is + closed. As a special case, if _n is omitted, and _w_o_r_d does not expand + to one or more digits or --, the standard output and standard error are + redirected as described previously. MMoovviinngg FFiillee DDeessccrriippttoorrss The redirection operator [_n]<<&&_d_i_g_i_t-- - moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard + moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard input (file descriptor 0) if _n is not specified. _d_i_g_i_t is closed after being duplicated to _n. @@ -1999,7 +2100,7 @@ RREEDDIIRREECCTTIIOONN [_n]>>&&_d_i_g_i_t-- - moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard + moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard output (file descriptor 1) if _n is not specified. OOppeenniinngg FFiillee DDeessccrriippttoorrss ffoorr RReeaaddiinngg aanndd WWrriittiinngg @@ -2007,117 +2108,117 @@ RREEDDIIRREECCTTIIOONN [_n]<<>>_w_o_r_d - causes the file whose name is the expansion of _w_o_r_d to be opened for - both reading and writing on file descriptor _n, or on file descriptor 0 + causes the file whose name is the expansion of _w_o_r_d to be opened for + both reading and writing on file descriptor _n, or on file descriptor 0 if _n is not specified. If the file does not exist, it is created. AALLIIAASSEESS - _A_l_i_a_s_e_s allow a string to be substituted for a word when it is used as - the first word of a simple command. The shell maintains a list of - aliases that may be set and unset with the aalliiaass and uunnaalliiaass builtin - commands (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The first word of each - simple command, if unquoted, is checked to see if it has an alias. If - so, that word is replaced by the text of the alias. The characters //, - $$, ``, and == and any of the shell _m_e_t_a_c_h_a_r_a_c_t_e_r_s or quoting characters + _A_l_i_a_s_e_s allow a string to be substituted for a word when it is used as + the first word of a simple command. The shell maintains a list of + aliases that may be set and unset with the aalliiaass and uunnaalliiaass builtin + commands (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The first word of each + simple command, if unquoted, is checked to see if it has an alias. If + so, that word is replaced by the text of the alias. The characters //, + $$, ``, and == and any of the shell _m_e_t_a_c_h_a_r_a_c_t_e_r_s or quoting characters listed above may not appear in an alias name. The replacement text may - contain any valid shell input, including shell metacharacters. The - first word of the replacement text is tested for aliases, but a word - that is identical to an alias being expanded is not expanded a second - time. This means that one may alias llss to llss --FF, for instance, and - bbaasshh does not try to recursively expand the replacement text. If the - last character of the alias value is a _b_l_a_n_k, then the next command + contain any valid shell input, including shell metacharacters. The + first word of the replacement text is tested for aliases, but a word + that is identical to an alias being expanded is not expanded a second + time. This means that one may alias llss to llss --FF, for instance, and + bbaasshh does not try to recursively expand the replacement text. If the + last character of the alias value is a _b_l_a_n_k, then the next command word following the alias is also checked for alias expansion. Aliases are created and listed with the aalliiaass command, and removed with the uunnaalliiaass command. - There is no mechanism for using arguments in the replacement text. If - arguments are needed, a shell function should be used (see FFUUNNCCTTIIOONNSS + There is no mechanism for using arguments in the replacement text. If + arguments are needed, a shell function should be used (see FFUUNNCCTTIIOONNSS below). - Aliases are not expanded when the shell is not interactive, unless the - eexxppaanndd__aalliiaasseess shell option is set using sshhoopptt (see the description of + Aliases are not expanded when the shell is not interactive, unless the + eexxppaanndd__aalliiaasseess shell option is set using sshhoopptt (see the description of sshhoopptt under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - The rules concerning the definition and use of aliases are somewhat - confusing. BBaasshh always reads at least one complete line of input - before executing any of the commands on that line. Aliases are - expanded when a command is read, not when it is executed. Therefore, - an alias definition appearing on the same line as another command does - not take effect until the next line of input is read. The commands + The rules concerning the definition and use of aliases are somewhat + confusing. BBaasshh always reads at least one complete line of input + before executing any of the commands on that line. Aliases are + expanded when a command is read, not when it is executed. Therefore, + an alias definition appearing on the same line as another command does + not take effect until the next line of input is read. The commands following the alias definition on that line are not affected by the new - alias. This behavior is also an issue when functions are executed. - Aliases are expanded when a function definition is read, not when the - function is executed, because a function definition is itself a com- + alias. This behavior is also an issue when functions are executed. + Aliases are expanded when a function definition is read, not when the + function is executed, because a function definition is itself a com- pound command. As a consequence, aliases defined in a function are not - available until after that function is executed. To be safe, always - put alias definitions on a separate line, and do not use aalliiaass in com- + available until after that function is executed. To be safe, always + put alias definitions on a separate line, and do not use aalliiaass in com- pound commands. For almost every purpose, aliases are superseded by shell functions. FFUUNNCCTTIIOONNSS - A shell function, defined as described above under SSHHEELLLL GGRRAAMMMMAARR, - stores a series of commands for later execution. When the name of a - shell function is used as a simple command name, the list of commands + A shell function, defined as described above under SSHHEELLLL GGRRAAMMMMAARR, + stores a series of commands for later execution. When the name of a + shell function is used as a simple command name, the list of commands associated with that function name is executed. Functions are executed - in the context of the current shell; no new process is created to - interpret them (contrast this with the execution of a shell script). - When a function is executed, the arguments to the function become the + in the context of the current shell; no new process is created to + interpret them (contrast this with the execution of a shell script). + When a function is executed, the arguments to the function become the positional parameters during its execution. The special parameter ## is - updated to reflect the change. Special parameter 00 is unchanged. The - first element of the FFUUNNCCNNAAMMEE variable is set to the name of the func- + updated to reflect the change. Special parameter 00 is unchanged. The + first element of the FFUUNNCCNNAAMMEE variable is set to the name of the func- tion while the function is executing. - All other aspects of the shell execution environment are identical + All other aspects of the shell execution environment are identical between a function and its caller with these exceptions: the DDEEBBUUGG and - RREETTUURRNN traps (see the description of the ttrraapp builtin under SSHHEELLLL - BBUUIILLTTIINN CCOOMMMMAANNDDSS below) are not inherited unless the function has been - given the ttrraaccee attribute (see the description of the ddeeccllaarree builtin - below) or the --oo ffuunnccttrraaccee shell option has been enabled with the sseett - builtin (in which case all functions inherit the DDEEBBUUGG and RREETTUURRNN - traps), and the EERRRR trap is not inherited unless the --oo eerrrrttrraaccee shell + RREETTUURRNN traps (see the description of the ttrraapp builtin under SSHHEELLLL + BBUUIILLTTIINN CCOOMMMMAANNDDSS below) are not inherited unless the function has been + given the ttrraaccee attribute (see the description of the ddeeccllaarree builtin + below) or the --oo ffuunnccttrraaccee shell option has been enabled with the sseett + builtin (in which case all functions inherit the DDEEBBUUGG and RREETTUURRNN + traps), and the EERRRR trap is not inherited unless the --oo eerrrrttrraaccee shell option has been enabled. - Variables local to the function may be declared with the llooccaall builtin + Variables local to the function may be declared with the llooccaall builtin command. Ordinarily, variables and their values are shared between the function and its caller. - The FFUUNNCCNNEESSTT variable, if set to a numeric value greater than 0, - defines a maximum function nesting level. Function invocations that + The FFUUNNCCNNEESSTT variable, if set to a numeric value greater than 0, + defines a maximum function nesting level. Function invocations that exceed the limit cause the entire command to abort. - If the builtin command rreettuurrnn is executed in a function, the function - completes and execution resumes with the next command after the func- - tion call. Any command associated with the RREETTUURRNN trap is executed + If the builtin command rreettuurrnn is executed in a function, the function + completes and execution resumes with the next command after the func- + tion call. Any command associated with the RREETTUURRNN trap is executed before execution resumes. When a function completes, the values of the - positional parameters and the special parameter ## are restored to the + positional parameters and the special parameter ## are restored to the values they had prior to the function's execution. - Function names and definitions may be listed with the --ff option to the + Function names and definitions may be listed with the --ff option to the ddeeccllaarree or ttyyppeesseett builtin commands. The --FF option to ddeeccllaarree or ttyyppee-- - sseett will list the function names only (and optionally the source file - and line number, if the eexxttddeebbuugg shell option is enabled). Functions - may be exported so that subshells automatically have them defined with - the --ff option to the eexxppoorrtt builtin. A function definition may be - deleted using the --ff option to the uunnsseett builtin. Note that shell + sseett will list the function names only (and optionally the source file + and line number, if the eexxttddeebbuugg shell option is enabled). Functions + may be exported so that subshells automatically have them defined with + the --ff option to the eexxppoorrtt builtin. A function definition may be + deleted using the --ff option to the uunnsseett builtin. Note that shell functions and variables with the same name may result in multiple iden- - tically-named entries in the environment passed to the shell's chil- + tically-named entries in the environment passed to the shell's chil- dren. Care should be taken in cases where this may cause a problem. Functions may be recursive. The FFUUNNCCNNEESSTT variable may be used to limit - the depth of the function call stack and restrict the number of func- - tion invocations. By default, no limit is imposed on the number of + the depth of the function call stack and restrict the number of func- + tion invocations. By default, no limit is imposed on the number of recursive calls. AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN - The shell allows arithmetic expressions to be evaluated, under certain - circumstances (see the lleett and ddeeccllaarree builtin commands and AArriitthhmmeettiicc - EExxppaannssiioonn). Evaluation is done in fixed-width integers with no check - for overflow, though division by 0 is trapped and flagged as an error. - The operators and their precedence, associativity, and values are the - same as in the C language. The following list of operators is grouped - into levels of equal-precedence operators. The levels are listed in + The shell allows arithmetic expressions to be evaluated, under certain + circumstances (see the lleett and ddeeccllaarree builtin commands and AArriitthhmmeettiicc + EExxppaannssiioonn). Evaluation is done in fixed-width integers with no check + for overflow, though division by 0 is trapped and flagged as an error. + The operators and their precedence, associativity, and values are the + same as in the C language. The following list of operators is grouped + into levels of equal-precedence operators. The levels are listed in order of decreasing precedence. _i_d++++ _i_d---- @@ -2145,46 +2246,46 @@ AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN _e_x_p_r_1 ,, _e_x_p_r_2 comma - Shell variables are allowed as operands; parameter expansion is per- + Shell variables are allowed as operands; parameter expansion is per- formed before the expression is evaluated. Within an expression, shell - variables may also be referenced by name without using the parameter - expansion syntax. A shell variable that is null or unset evaluates to + variables may also be referenced by name without using the parameter + expansion syntax. A shell variable that is null or unset evaluates to 0 when referenced by name without using the parameter expansion syntax. - The value of a variable is evaluated as an arithmetic expression when - it is referenced, or when a variable which has been given the _i_n_t_e_g_e_r + The value of a variable is evaluated as an arithmetic expression when + it is referenced, or when a variable which has been given the _i_n_t_e_g_e_r attribute using ddeeccllaarree --ii is assigned a value. A null value evaluates - to 0. A shell variable need not have its _i_n_t_e_g_e_r attribute turned on + to 0. A shell variable need not have its _i_n_t_e_g_e_r attribute turned on to be used in an expression. Constants with a leading 0 are interpreted as octal numbers. A leading - 0x or 0X denotes hexadecimal. Otherwise, numbers take the form - [_b_a_s_e_#]n, where the optional _b_a_s_e is a decimal number between 2 and 64 - representing the arithmetic base, and _n is a number in that base. If - _b_a_s_e_# is omitted, then base 10 is used. The digits greater than 9 are - represented by the lowercase letters, the uppercase letters, @, and _, - in that order. If _b_a_s_e is less than or equal to 36, lowercase and - uppercase letters may be used interchangeably to represent numbers - between 10 and 35. - - Operators are evaluated in order of precedence. Sub-expressions in - parentheses are evaluated first and may override the precedence rules + 0x or 0X denotes hexadecimal. Otherwise, numbers take the form + [_b_a_s_e_#]n, where the optional _b_a_s_e is a decimal number between 2 and 64 + representing the arithmetic base, and _n is a number in that base. If + _b_a_s_e_# is omitted, then base 10 is used. When specifying _n, the digits + greater< than 9 are represented by the lowercase letters, the uppercase + letters, @, and _, in that order. If _b_a_s_e is less than or equal to 36, + lowercase and uppercase letters may be used interchangeably to repre- + sent numbers between 10 and 35. + + Operators are evaluated in order of precedence. Sub-expressions in + parentheses are evaluated first and may override the precedence rules above. CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS - Conditional expressions are used by the [[[[ compound command and the - tteesstt and [[ builtin commands to test file attributes and perform string - and arithmetic comparisons. Expressions are formed from the following - unary or binary primaries. If any _f_i_l_e argument to one of the pri- + Conditional expressions are used by the [[[[ compound command and the + tteesstt and [[ builtin commands to test file attributes and perform string + and arithmetic comparisons. Expressions are formed from the following + unary or binary primaries. If any _f_i_l_e argument to one of the pri- maries is of the form _/_d_e_v_/_f_d_/_n, then file descriptor _n is checked. If - the _f_i_l_e argument to one of the primaries is one of _/_d_e_v_/_s_t_d_i_n, - _/_d_e_v_/_s_t_d_o_u_t, or _/_d_e_v_/_s_t_d_e_r_r, file descriptor 0, 1, or 2, respectively, + the _f_i_l_e argument to one of the primaries is one of _/_d_e_v_/_s_t_d_i_n, + _/_d_e_v_/_s_t_d_o_u_t, or _/_d_e_v_/_s_t_d_e_r_r, file descriptor 0, 1, or 2, respectively, is checked. Unless otherwise specified, primaries that operate on files follow sym- bolic links and operate on the target of the link, rather than the link itself. - When used with [[[[, the << and >> operators sort lexicographically using + When used with [[[[, the << and >> operators sort lexicographically using the current locale. The tteesstt command sorts using ASCII ordering. --aa _f_i_l_e @@ -2223,28 +2324,31 @@ CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS --LL _f_i_l_e True if _f_i_l_e exists and is a symbolic link. --NN _f_i_l_e - True if _f_i_l_e exists and has been modified since it was last + True if _f_i_l_e exists and has been modified since it was last read. --OO _f_i_l_e True if _f_i_l_e exists and is owned by the effective user id. --SS _f_i_l_e True if _f_i_l_e exists and is a socket. _f_i_l_e_1 --eeff _f_i_l_e_2 - True if _f_i_l_e_1 and _f_i_l_e_2 refer to the same device and inode num- + True if _f_i_l_e_1 and _f_i_l_e_2 refer to the same device and inode num- bers. _f_i_l_e_1 -nntt _f_i_l_e_2 - True if _f_i_l_e_1 is newer (according to modification date) than + True if _f_i_l_e_1 is newer (according to modification date) than _f_i_l_e_2, or if _f_i_l_e_1 exists and _f_i_l_e_2 does not. _f_i_l_e_1 -oott _f_i_l_e_2 - True if _f_i_l_e_1 is older than _f_i_l_e_2, or if _f_i_l_e_2 exists and _f_i_l_e_1 + True if _f_i_l_e_1 is older than _f_i_l_e_2, or if _f_i_l_e_2 exists and _f_i_l_e_1 does not. --oo _o_p_t_n_a_m_e - True if the shell option _o_p_t_n_a_m_e is enabled. See the list of - options under the description of the --oo option to the sseett + True if the shell option _o_p_t_n_a_m_e is enabled. See the list of + options under the description of the --oo option to the sseett builtin below. --vv _v_a_r_n_a_m_e - True if the shell variable _v_a_r_n_a_m_e is set (has been assigned a + True if the shell variable _v_a_r_n_a_m_e is set (has been assigned a value). + --RR _v_a_r_n_a_m_e + True if the shell variable _v_a_r_n_a_m_e is set and is a name refer- + ence. --zz _s_t_r_i_n_g True if the length of _s_t_r_i_n_g is zero. _s_t_r_i_n_g @@ -2254,7 +2358,9 @@ CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS _s_t_r_i_n_g_1 ==== _s_t_r_i_n_g_2 _s_t_r_i_n_g_1 == _s_t_r_i_n_g_2 True if the strings are equal. == should be used with the tteesstt - command for POSIX conformance. + command for POSIX conformance. When used with the [[[[ command, + this performs pattern matching as described above (CCoommppoouunndd CCoomm-- + mmaannddss). _s_t_r_i_n_g_1 !!== _s_t_r_i_n_g_2 True if the strings are not equal. @@ -2359,7 +2465,6 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENN The shell has an _e_x_e_c_u_t_i_o_n _e_n_v_i_r_o_n_m_e_n_t, which consists of the follow- ing: - +o open files inherited by the shell at invocation, as modified by redirections supplied to the eexxeecc builtin @@ -2453,8 +2558,8 @@ EENNVVIIRROONNMMEENNTT just those that precede the command name. When bbaasshh invokes an external command, the variable __ is set to the - full file name of the command and passed to that command in its envi- - ronment. + full filename of the command and passed to that command in its environ- + ment. EEXXIITT SSTTAATTUUSS The exit status of an executed command is the value returned by the @@ -2803,175 +2908,198 @@ RREEAADDLLIINNEE If set to OOnn, readline attempts to bind the control characters treated specially by the kernel's terminal driver to their read- line equivalents. + ccoolloorreedd--ssttaattss ((OOffff)) + If set to OOnn, readline displays possible completions using dif- + ferent colors to indicate their file type. The color defini- + tions are taken from the value of the LLSS__CCOOLLOORRSS environment + variable. ccoommmmeenntt--bbeeggiinn ((````##'''')) - The string that is inserted when the readline iinnsseerrtt--ccoommmmeenntt + The string that is inserted when the readline iinnsseerrtt--ccoommmmeenntt command is executed. This command is bound to MM--## in emacs mode and to ## in vi command mode. ccoommpplleettiioonn--iiggnnoorree--ccaassee ((OOffff)) If set to OOnn, readline performs filename matching and completion in a case-insensitive fashion. ccoommpplleettiioonn--pprreeffiixx--ddiissppllaayy--lleennggtthh ((00)) - The length in characters of the common prefix of a list of pos- - sible completions that is displayed without modification. When - set to a value greater than zero, common prefixes longer than - this value are replaced with an ellipsis when displaying possi- + The length in characters of the common prefix of a list of pos- + sible completions that is displayed without modification. When + set to a value greater than zero, common prefixes longer than + this value are replaced with an ellipsis when displaying possi- ble completions. ccoommpplleettiioonn--qquueerryy--iitteemmss ((110000)) - This determines when the user is queried about viewing the num- - ber of possible completions generated by the ppoossssiibbllee--ccoommppllee-- - ttiioonnss command. It may be set to any integer value greater than - or equal to zero. If the number of possible completions is + This determines when the user is queried about viewing the num- + ber of possible completions generated by the ppoossssiibbllee--ccoommppllee-- + ttiioonnss command. It may be set to any integer value greater than + or equal to zero. If the number of possible completions is greater than or equal to the value of this variable, the user is - asked whether or not he wishes to view them; otherwise they are + asked whether or not he wishes to view them; otherwise they are simply listed on the terminal. ccoonnvveerrtt--mmeettaa ((OOnn)) - If set to OOnn, readline will convert characters with the eighth + If set to OOnn, readline will convert characters with the eighth bit set to an ASCII key sequence by stripping the eighth bit and - prefixing an escape character (in effect, using escape as the + prefixing an escape character (in effect, using escape as the _m_e_t_a _p_r_e_f_i_x). ddiissaabbllee--ccoommpplleettiioonn ((OOffff)) If set to OOnn, readline will inhibit word completion. Completion - characters will be inserted into the line as if they had been + characters will be inserted into the line as if they had been mapped to sseellff--iinnsseerrtt. eeddiittiinngg--mmooddee ((eemmaaccss)) Controls whether readline begins with a set of key bindings sim- ilar to _E_m_a_c_s or _v_i. eeddiittiinngg--mmooddee can be set to either eemmaaccss or vvii. eecchhoo--ccoonnttrrooll--cchhaarraacctteerrss ((OOnn)) - When set to OOnn, on operating systems that indicate they support + When set to OOnn, on operating systems that indicate they support it, readline echoes a character corresponding to a signal gener- ated from the keyboard. eennaabbllee--kkeeyyppaadd ((OOffff)) When set to OOnn, readline will try to enable the application key- - pad when it is called. Some systems need this to enable the + pad when it is called. Some systems need this to enable the arrow keys. eennaabbllee--mmeettaa--kkeeyy ((OOnn)) - When set to OOnn, readline will try to enable any meta modifier - key the terminal claims to support when it is called. On many + When set to OOnn, readline will try to enable any meta modifier + key the terminal claims to support when it is called. On many terminals, the meta key is used to send eight-bit characters. eexxppaanndd--ttiillddee ((OOffff)) - If set to OOnn, tilde expansion is performed when readline + If set to OOnn, tilde expansion is performed when readline attempts word completion. hhiissttoorryy--pprreesseerrvvee--ppooiinntt ((OOffff)) - If set to OOnn, the history code attempts to place point at the - same location on each history line retrieved with pprreevviioouuss--hhiiss-- + If set to OOnn, the history code attempts to place point at the + same location on each history line retrieved with pprreevviioouuss--hhiiss-- ttoorryy or nneexxtt--hhiissttoorryy. hhiissttoorryy--ssiizzee ((00)) - Set the maximum number of history entries saved in the history - list. If set to zero, the number of entries in the history list - is not limited. + Set the maximum number of history entries saved in the history + list. If set to zero, any existing history entries are deleted + and no new entries are saved. If set to a value less than zero, + the number of history entries is not limited. By default, the + number of history entries is not limited. hhoorriizzoonnttaall--ssccrroollll--mmooddee ((OOffff)) - When set to OOnn, makes readline use a single line for display, + When set to OOnn, makes readline use a single line for display, scrolling the input horizontally on a single screen line when it - becomes longer than the screen width rather than wrapping to a + becomes longer than the screen width rather than wrapping to a new line. iinnppuutt--mmeettaa ((OOffff)) - If set to OOnn, readline will enable eight-bit input (that is, it - will not strip the high bit from the characters it reads), + If set to OOnn, readline will enable eight-bit input (that is, it + will not strip the high bit from the characters it reads), regardless of what the terminal claims it can support. The name mmeettaa--ffllaagg is a synonym for this variable. iisseeaarrcchh--tteerrmmiinnaattoorrss ((````CC--[[CC--JJ'''')) - The string of characters that should terminate an incremental - search without subsequently executing the character as a com- - mand. If this variable has not been given a value, the charac- + The string of characters that should terminate an incremental + search without subsequently executing the character as a com- + mand. If this variable has not been given a value, the charac- ters _E_S_C and _C_-_J will terminate an incremental search. kkeeyymmaapp ((eemmaaccss)) - Set the current readline keymap. The set of valid keymap names - is _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_d_a_r_d_, _e_m_a_c_s_-_m_e_t_a_, _e_m_a_c_s_-_c_t_l_x_, _v_i_, _v_i_-_c_o_m_- - _m_a_n_d, and _v_i_-_i_n_s_e_r_t. _v_i is equivalent to _v_i_-_c_o_m_m_a_n_d; _e_m_a_c_s is - equivalent to _e_m_a_c_s_-_s_t_a_n_d_a_r_d. The default value is _e_m_a_c_s; the + Set the current readline keymap. The set of valid keymap names + is _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_d_a_r_d_, _e_m_a_c_s_-_m_e_t_a_, _e_m_a_c_s_-_c_t_l_x_, _v_i_, _v_i_-_c_o_m_- + _m_a_n_d, and _v_i_-_i_n_s_e_r_t. _v_i is equivalent to _v_i_-_c_o_m_m_a_n_d; _e_m_a_c_s is + equivalent to _e_m_a_c_s_-_s_t_a_n_d_a_r_d. The default value is _e_m_a_c_s; the value of eeddiittiinngg--mmooddee also affects the default keymap. + kkeeyysseeqq--ttiimmeeoouutt ((550000)) + Specifies the duration _r_e_a_d_l_i_n_e will wait for a character when + reading an ambiguous key sequence (one that can form a complete + key sequence using the input read so far, or can take additional + input to complete a longer key sequence). If no input is + received within the timeout, _r_e_a_d_l_i_n_e will use the shorter but + complete key sequence. The value is specified in milliseconds, + so a value of 1000 means that _r_e_a_d_l_i_n_e will wait one second for + additional input. If this variable is set to a value less than + or equal to zero, or to a non-numeric value, _r_e_a_d_l_i_n_e will wait + until another key is pressed to decide which key sequence to + complete. mmaarrkk--ddiirreeccttoorriieess ((OOnn)) If set to OOnn, completed directory names have a slash appended. mmaarrkk--mmooddiiffiieedd--lliinneess ((OOffff)) - If set to OOnn, history lines that have been modified are dis- + If set to OOnn, history lines that have been modified are dis- played with a preceding asterisk (**). mmaarrkk--ssyymmlliinnkkeedd--ddiirreeccttoorriieess ((OOffff)) If set to OOnn, completed names which are symbolic links to direc- - tories have a slash appended (subject to the value of + tories have a slash appended (subject to the value of mmaarrkk--ddiirreeccttoorriieess). mmaattcchh--hhiiddddeenn--ffiilleess ((OOnn)) - This variable, when set to OOnn, causes readline to match files - whose names begin with a `.' (hidden files) when performing - filename completion. If set to OOffff, the leading `.' must be + This variable, when set to OOnn, causes readline to match files + whose names begin with a `.' (hidden files) when performing + filename completion. If set to OOffff, the leading `.' must be supplied by the user in the filename to be completed. mmeennuu--ccoommpplleettee--ddiissppllaayy--pprreeffiixx ((OOffff)) - If set to OOnn, menu completion displays the common prefix of the + If set to OOnn, menu completion displays the common prefix of the list of possible completions (which may be empty) before cycling through the list. oouuttppuutt--mmeettaa ((OOffff)) - If set to OOnn, readline will display characters with the eighth + If set to OOnn, readline will display characters with the eighth bit set directly rather than as a meta-prefixed escape sequence. ppaaggee--ccoommpplleettiioonnss ((OOnn)) - If set to OOnn, readline uses an internal _m_o_r_e-like pager to dis- + If set to OOnn, readline uses an internal _m_o_r_e-like pager to dis- play a screenful of possible completions at a time. pprriinntt--ccoommpplleettiioonnss--hhoorriizzoonnttaallllyy ((OOffff)) - If set to OOnn, readline will display completions with matches - sorted horizontally in alphabetical order, rather than down the + If set to OOnn, readline will display completions with matches + sorted horizontally in alphabetical order, rather than down the screen. rreevveerrtt--aallll--aatt--nneewwlliinnee ((OOffff)) - If set to OOnn, readline will undo all changes to history lines + If set to OOnn, readline will undo all changes to history lines before returning when aacccceepptt--lliinnee is executed. By default, his- - tory lines may be modified and retain individual undo lists + tory lines may be modified and retain individual undo lists across calls to rreeaaddlliinnee. sshhooww--aallll--iiff--aammbbiigguuoouuss ((OOffff)) - This alters the default behavior of the completion functions. + This alters the default behavior of the completion functions. If set to OOnn, words which have more than one possible completion - cause the matches to be listed immediately instead of ringing + cause the matches to be listed immediately instead of ringing the bell. sshhooww--aallll--iiff--uunnmmooddiiffiieedd ((OOffff)) - This alters the default behavior of the completion functions in + This alters the default behavior of the completion functions in a fashion similar to sshhooww--aallll--iiff--aammbbiigguuoouuss. If set to OOnn, words - which have more than one possible completion without any possi- - ble partial completion (the possible completions don't share a - common prefix) cause the matches to be listed immediately + which have more than one possible completion without any possi- + ble partial completion (the possible completions don't share a + common prefix) cause the matches to be listed immediately instead of ringing the bell. + sshhooww--mmooddee--iinn--pprroommpptt ((OOffff)) + If set to OOnn, add a character to the beginning of the prompt + indicating the editing mode: emacs (@), vi command (:) or vi + insertion (+). sskkiipp--ccoommpplleetteedd--tteexxtt ((OOffff)) - If set to OOnn, this alters the default completion behavior when - inserting a single match into the line. It's only active when - performing completion in the middle of a word. If enabled, - readline does not insert characters from the completion that - match characters after point in the word being completed, so + If set to OOnn, this alters the default completion behavior when + inserting a single match into the line. It's only active when + performing completion in the middle of a word. If enabled, + readline does not insert characters from the completion that + match characters after point in the word being completed, so portions of the word following the cursor are not duplicated. vviissiibbllee--ssttaattss ((OOffff)) - If set to OOnn, a character denoting a file's type as reported by - _s_t_a_t(2) is appended to the filename when listing possible com- + If set to OOnn, a character denoting a file's type as reported by + _s_t_a_t(2) is appended to the filename when listing possible com- pletions. RReeaaddlliinnee CCoonnddiittiioonnaall CCoonnssttrruuccttss - Readline implements a facility similar in spirit to the conditional - compilation features of the C preprocessor which allows key bindings - and variable settings to be performed as the result of tests. There + Readline implements a facility similar in spirit to the conditional + compilation features of the C preprocessor which allows key bindings + and variable settings to be performed as the result of tests. There are four parser directives used. - $$iiff The $$iiff construct allows bindings to be made based on the edit- - ing mode, the terminal being used, or the application using - readline. The text of the test extends to the end of the line; + $$iiff The $$iiff construct allows bindings to be made based on the edit- + ing mode, the terminal being used, or the application using + readline. The text of the test extends to the end of the line; no characters are required to isolate it. - mmooddee The mmooddee== form of the $$iiff directive is used to test - whether readline is in emacs or vi mode. This may be - used in conjunction with the sseett kkeeyymmaapp command, for - instance, to set bindings in the _e_m_a_c_s_-_s_t_a_n_d_a_r_d and - _e_m_a_c_s_-_c_t_l_x keymaps only if readline is starting out in + mmooddee The mmooddee== form of the $$iiff directive is used to test + whether readline is in emacs or vi mode. This may be + used in conjunction with the sseett kkeeyymmaapp command, for + instance, to set bindings in the _e_m_a_c_s_-_s_t_a_n_d_a_r_d and + _e_m_a_c_s_-_c_t_l_x keymaps only if readline is starting out in emacs mode. - tteerrmm The tteerrmm== form may be used to include terminal-specific + tteerrmm The tteerrmm== form may be used to include terminal-specific key bindings, perhaps to bind the key sequences output by the terminal's function keys. The word on the right side of the == is tested against the both full name of the ter- - minal and the portion of the terminal name before the - first --. This allows _s_u_n to match both _s_u_n and _s_u_n_-_c_m_d, + minal and the portion of the terminal name before the + first --. This allows _s_u_n to match both _s_u_n and _s_u_n_-_c_m_d, for instance. aapppplliiccaattiioonn The aapppplliiccaattiioonn construct is used to include application- specific settings. Each program using the readline - library sets the _a_p_p_l_i_c_a_t_i_o_n _n_a_m_e, and an initialization + library sets the _a_p_p_l_i_c_a_t_i_o_n _n_a_m_e, and an initialization file can test for a particular value. This could be used - to bind key sequences to functions useful for a specific - program. For instance, the following command adds a key - sequence that quotes the current or previous word in + to bind key sequences to functions useful for a specific + program. For instance, the following command adds a key + sequence that quotes the current or previous word in bbaasshh: $$iiff Bash @@ -2986,51 +3114,51 @@ RREEAADDLLIINNEE test fails. $$iinncclluuddee - This directive takes a single filename as an argument and reads - commands and bindings from that file. For example, the follow- + This directive takes a single filename as an argument and reads + commands and bindings from that file. For example, the follow- ing directive would read _/_e_t_c_/_i_n_p_u_t_r_c: $$iinncclluuddee _/_e_t_c_/_i_n_p_u_t_r_c SSeeaarrcchhiinngg - Readline provides commands for searching through the command history + Readline provides commands for searching through the command history (see HHIISSTTOORRYY below) for lines containing a specified string. There are two search modes: _i_n_c_r_e_m_e_n_t_a_l and _n_o_n_-_i_n_c_r_e_m_e_n_t_a_l. - Incremental searches begin before the user has finished typing the - search string. As each character of the search string is typed, read- + Incremental searches begin before the user has finished typing the + search string. As each character of the search string is typed, read- line displays the next entry from the history matching the string typed - so far. An incremental search requires only as many characters as - needed to find the desired history entry. The characters present in - the value of the iisseeaarrcchh--tteerrmmiinnaattoorrss variable are used to terminate an + so far. An incremental search requires only as many characters as + needed to find the desired history entry. The characters present in + the value of the iisseeaarrcchh--tteerrmmiinnaattoorrss variable are used to terminate an incremental search. If that variable has not been assigned a value the - Escape and Control-J characters will terminate an incremental search. - Control-G will abort an incremental search and restore the original - line. When the search is terminated, the history entry containing the + Escape and Control-J characters will terminate an incremental search. + Control-G will abort an incremental search and restore the original + line. When the search is terminated, the history entry containing the search string becomes the current line. - To find other matching entries in the history list, type Control-S or - Control-R as appropriate. This will search backward or forward in the - history for the next entry matching the search string typed so far. - Any other key sequence bound to a readline command will terminate the - search and execute that command. For instance, a _n_e_w_l_i_n_e will termi- + To find other matching entries in the history list, type Control-S or + Control-R as appropriate. This will search backward or forward in the + history for the next entry matching the search string typed so far. + Any other key sequence bound to a readline command will terminate the + search and execute that command. For instance, a _n_e_w_l_i_n_e will termi- nate the search and accept the line, thereby executing the command from the history list. Readline remembers the last incremental search string. If two Control- - Rs are typed without any intervening characters defining a new search + Rs are typed without any intervening characters defining a new search string, any remembered search string is used. - Non-incremental searches read the entire search string before starting - to search for matching history lines. The search string may be typed + Non-incremental searches read the entire search string before starting + to search for matching history lines. The search string may be typed by the user or be part of the contents of the current line. RReeaaddlliinnee CCoommmmaanndd NNaammeess - The following is a list of the names of the commands and the default + The following is a list of the names of the commands and the default key sequences to which they are bound. Command names without an accom- panying key sequence are unbound by default. In the following descrip- - tions, _p_o_i_n_t refers to the current cursor position, and _m_a_r_k refers to - a cursor position saved by the sseett--mmaarrkk command. The text between the + tions, _p_o_i_n_t refers to the current cursor position, and _m_a_r_k refers to + a cursor position saved by the sseett--mmaarrkk command. The text between the point and mark is referred to as the _r_e_g_i_o_n. CCoommmmaannddss ffoorr MMoovviinngg @@ -3046,17 +3174,17 @@ RREEAADDLLIINNEE Move forward to the end of the next word. Words are composed of alphanumeric characters (letters and digits). bbaacckkwwaarrdd--wwoorrdd ((MM--bb)) - Move back to the start of the current or previous word. Words + Move back to the start of the current or previous word. Words are composed of alphanumeric characters (letters and digits). sshheellll--ffoorrwwaarrdd--wwoorrdd - Move forward to the end of the next word. Words are delimited + Move forward to the end of the next word. Words are delimited by non-quoted shell metacharacters. sshheellll--bbaacckkwwaarrdd--wwoorrdd - Move back to the start of the current or previous word. Words + Move back to the start of the current or previous word. Words are delimited by non-quoted shell metacharacters. cclleeaarr--ssccrreeeenn ((CC--ll)) - Clear the screen leaving the current line at the top of the - screen. With an argument, refresh the current line without + Clear the screen leaving the current line at the top of the + screen. With an argument, refresh the current line without clearing the screen. rreeddrraaww--ccuurrrreenntt--lliinnee Refresh the current line. @@ -3064,95 +3192,100 @@ RREEAADDLLIINNEE CCoommmmaannddss ffoorr MMaanniippuullaattiinngg tthhee HHiissttoorryy aacccceepptt--lliinnee ((NNeewwlliinnee,, RReettuurrnn)) Accept the line regardless of where the cursor is. If this line - is non-empty, add it to the history list according to the state - of the HHIISSTTCCOONNTTRROOLL variable. If the line is a modified history + is non-empty, add it to the history list according to the state + of the HHIISSTTCCOONNTTRROOLL variable. If the line is a modified history line, then restore the history line to its original state. pprreevviioouuss--hhiissttoorryy ((CC--pp)) Fetch the previous command from the history list, moving back in the list. nneexxtt--hhiissttoorryy ((CC--nn)) - Fetch the next command from the history list, moving forward in + Fetch the next command from the history list, moving forward in the list. bbeeggiinnnniinngg--ooff--hhiissttoorryy ((MM--<<)) Move to the first line in the history. eenndd--ooff--hhiissttoorryy ((MM-->>)) - Move to the end of the input history, i.e., the line currently + Move to the end of the input history, i.e., the line currently being entered. rreevveerrssee--sseeaarrcchh--hhiissttoorryy ((CC--rr)) - Search backward starting at the current line and moving `up' - through the history as necessary. This is an incremental + Search backward starting at the current line and moving `up' + through the history as necessary. This is an incremental search. ffoorrwwaarrdd--sseeaarrcchh--hhiissttoorryy ((CC--ss)) - Search forward starting at the current line and moving `down' - through the history as necessary. This is an incremental + Search forward starting at the current line and moving `down' + through the history as necessary. This is an incremental search. nnoonn--iinnccrreemmeennttaall--rreevveerrssee--sseeaarrcchh--hhiissttoorryy ((MM--pp)) Search backward through the history starting at the current line - using a non-incremental search for a string supplied by the + using a non-incremental search for a string supplied by the user. nnoonn--iinnccrreemmeennttaall--ffoorrwwaarrdd--sseeaarrcchh--hhiissttoorryy ((MM--nn)) - Search forward through the history using a non-incremental + Search forward through the history using a non-incremental search for a string supplied by the user. hhiissttoorryy--sseeaarrcchh--ffoorrwwaarrdd - Search forward through the history for the string of characters - between the start of the current line and the point. This is a + Search forward through the history for the string of characters + between the start of the current line and the point. This is a non-incremental search. hhiissttoorryy--sseeaarrcchh--bbaacckkwwaarrdd Search backward through the history for the string of characters - between the start of the current line and the point. This is a + between the start of the current line and the point. This is a non-incremental search. yyaannkk--nntthh--aarrgg ((MM--CC--yy)) - Insert the first argument to the previous command (usually the + Insert the first argument to the previous command (usually the second word on the previous line) at point. With an argument _n, - insert the _nth word from the previous command (the words in the - previous command begin with word 0). A negative argument + insert the _nth word from the previous command (the words in the + previous command begin with word 0). A negative argument inserts the _nth word from the end of the previous command. Once - the argument _n is computed, the argument is extracted as if the + the argument _n is computed, the argument is extracted as if the "!_n" history expansion had been specified. yyaannkk--llaasstt--aarrgg ((MM--..,, MM--__)) - Insert the last argument to the previous command (the last word + Insert the last argument to the previous command (the last word of the previous history entry). With a numeric argument, behave - exactly like yyaannkk--nntthh--aarrgg. Successive calls to yyaannkk--llaasstt--aarrgg - move back through the history list, inserting the last word (or - the word specified by the argument to the first call) of each + exactly like yyaannkk--nntthh--aarrgg. Successive calls to yyaannkk--llaasstt--aarrgg + move back through the history list, inserting the last word (or + the word specified by the argument to the first call) of each line in turn. Any numeric argument supplied to these successive - calls determines the direction to move through the history. A - negative argument switches the direction through the history + calls determines the direction to move through the history. A + negative argument switches the direction through the history (back or forward). The history expansion facilities are used to - extract the last argument, as if the "!$" history expansion had - been specified. + extract the last word, as if the "!$" history expansion had been + specified. sshheellll--eexxppaanndd--lliinnee ((MM--CC--ee)) Expand the line as the shell does. This performs alias and his- tory expansion as well as all of the shell word expansions. See - HHIISSTTOORRYY EEXXPPAANNSSIIOONN below for a description of history expansion. + HHIISSTTOORRYY EEXXPPAANNSSIIOONN below for a description of history expansion. hhiissttoorryy--eexxppaanndd--lliinnee ((MM--^^)) - Perform history expansion on the current line. See HHIISSTTOORRYY + Perform history expansion on the current line. See HHIISSTTOORRYY EEXXPPAANNSSIIOONN below for a description of history expansion. mmaaggiicc--ssppaaccee - Perform history expansion on the current line and insert a + Perform history expansion on the current line and insert a space. See HHIISSTTOORRYY EEXXPPAANNSSIIOONN below for a description of history expansion. aalliiaass--eexxppaanndd--lliinnee - Perform alias expansion on the current line. See AALLIIAASSEESS above + Perform alias expansion on the current line. See AALLIIAASSEESS above for a description of alias expansion. hhiissttoorryy--aanndd--aalliiaass--eexxppaanndd--lliinnee Perform history and alias expansion on the current line. iinnsseerrtt--llaasstt--aarrgguummeenntt ((MM--..,, MM--__)) A synonym for yyaannkk--llaasstt--aarrgg. ooppeerraattee--aanndd--ggeett--nneexxtt ((CC--oo)) - Accept the current line for execution and fetch the next line - relative to the current line from the history for editing. Any + Accept the current line for execution and fetch the next line + relative to the current line from the history for editing. Any argument is ignored. eeddiitt--aanndd--eexxeeccuuttee--ccoommmmaanndd ((CC--xxCC--ee)) - Invoke an editor on the current command line, and execute the - result as shell commands. BBaasshh attempts to invoke $$VVIISSUUAALL, + Invoke an editor on the current command line, and execute the + result as shell commands. BBaasshh attempts to invoke $$VVIISSUUAALL, $$EEDDIITTOORR, and _e_m_a_c_s as the editor, in that order. CCoommmmaannddss ffoorr CChhaannggiinngg TTeexxtt + _e_n_d_-_o_f_-_f_i_l_e ((uussuuaallllyy CC--dd)) + The character indicating end-of-file as set, for example, by + ``stty''. If this character is read when there are no charac- + ters on the line, and point is at the beginning of the line, + Readline interprets it as the end of input and returns EEOOFF. ddeelleettee--cchhaarr ((CC--dd)) - Delete the character at point. If point is at the beginning of - the line, there are no characters in the line, and the last - character typed was not bound to ddeelleettee--cchhaarr, then return EEOOFF. + Delete the character at point. If this function is bound to the + same character as the tty EEOOFF character, as CC--dd commonly is, see + above for the effects. bbaacckkwwaarrdd--ddeelleettee--cchhaarr ((RRuubboouutt)) Delete the character behind the cursor. When given a numeric argument, save the deleted text on the kill ring. @@ -3350,165 +3483,168 @@ RREEAADDLLIINNEE ccaallll--llaasstt--kkbbdd--mmaaccrroo ((CC--xx ee)) Re-execute the last keyboard macro defined, by making the char- acters in the macro appear as if typed at the keyboard. + pprriinntt--llaasstt--kkbbdd--mmaaccrroo (()) + Print the last keyboard macro defined in a format suitable for + the _i_n_p_u_t_r_c file. MMiisscceellllaanneeoouuss rree--rreeaadd--iinniitt--ffiillee ((CC--xx CC--rr)) - Read in the contents of the _i_n_p_u_t_r_c file, and incorporate any + Read in the contents of the _i_n_p_u_t_r_c file, and incorporate any bindings or variable assignments found there. aabboorrtt ((CC--gg)) - Abort the current editing command and ring the terminal's bell + Abort the current editing command and ring the terminal's bell (subject to the setting of bbeellll--ssttyyllee). ddoo--uuppppeerrccaassee--vveerrssiioonn ((MM--aa,, MM--bb,, MM--_x,, ......)) - If the metafied character _x is lowercase, run the command that + If the metafied character _x is lowercase, run the command that is bound to the corresponding uppercase character. pprreeffiixx--mmeettaa ((EESSCC)) Metafy the next character typed. EESSCC ff is equivalent to MMeettaa--ff. uunnddoo ((CC--__,, CC--xx CC--uu)) Incremental undo, separately remembered for each line. rreevveerrtt--lliinnee ((MM--rr)) - Undo all changes made to this line. This is like executing the - uunnddoo command enough times to return the line to its initial + Undo all changes made to this line. This is like executing the + uunnddoo command enough times to return the line to its initial state. ttiillddee--eexxppaanndd ((MM--&&)) Perform tilde expansion on the current word. sseett--mmaarrkk ((CC--@@,, MM--<<ssppaaccee>>)) - Set the mark to the point. If a numeric argument is supplied, + Set the mark to the point. If a numeric argument is supplied, the mark is set to that position. eexxcchhaannggee--ppooiinntt--aanndd--mmaarrkk ((CC--xx CC--xx)) - Swap the point with the mark. The current cursor position is - set to the saved position, and the old cursor position is saved + Swap the point with the mark. The current cursor position is + set to the saved position, and the old cursor position is saved as the mark. cchhaarraacctteerr--sseeaarrcchh ((CC--]])) A character is read and point is moved to the next occurrence of - that character. A negative count searches for previous occur- + that character. A negative count searches for previous occur- rences. cchhaarraacctteerr--sseeaarrcchh--bbaacckkwwaarrdd ((MM--CC--]])) - A character is read and point is moved to the previous occur- - rence of that character. A negative count searches for subse- + A character is read and point is moved to the previous occur- + rence of that character. A negative count searches for subse- quent occurrences. sskkiipp--ccssii--sseeqquueennccee - Read enough characters to consume a multi-key sequence such as - those defined for keys like Home and End. Such sequences begin + Read enough characters to consume a multi-key sequence such as + those defined for keys like Home and End. Such sequences begin with a Control Sequence Indicator (CSI), usually ESC-[. If this - sequence is bound to "\[", keys producing such sequences will - have no effect unless explicitly bound to a readline command, - instead of inserting stray characters into the editing buffer. + sequence is bound to "\[", keys producing such sequences will + have no effect unless explicitly bound to a readline command, + instead of inserting stray characters into the editing buffer. This is unbound by default, but usually bound to ESC-[. iinnsseerrtt--ccoommmmeenntt ((MM--##)) - Without a numeric argument, the value of the readline ccoomm-- - mmeenntt--bbeeggiinn variable is inserted at the beginning of the current + Without a numeric argument, the value of the readline ccoomm-- + mmeenntt--bbeeggiinn variable is inserted at the beginning of the current line. If a numeric argument is supplied, this command acts as a - toggle: if the characters at the beginning of the line do not - match the value of ccoommmmeenntt--bbeeggiinn, the value is inserted, other- + toggle: if the characters at the beginning of the line do not + match the value of ccoommmmeenntt--bbeeggiinn, the value is inserted, other- wise the characters in ccoommmmeenntt--bbeeggiinn are deleted from the begin- - ning of the line. In either case, the line is accepted as if a - newline had been typed. The default value of ccoommmmeenntt--bbeeggiinn - causes this command to make the current line a shell comment. - If a numeric argument causes the comment character to be + ning of the line. In either case, the line is accepted as if a + newline had been typed. The default value of ccoommmmeenntt--bbeeggiinn + causes this command to make the current line a shell comment. + If a numeric argument causes the comment character to be removed, the line will be executed by the shell. gglloobb--ccoommpplleettee--wwoorrdd ((MM--gg)) - The word before point is treated as a pattern for pathname - expansion, with an asterisk implicitly appended. This pattern - is used to generate a list of matching file names for possible + The word before point is treated as a pattern for pathname + expansion, with an asterisk implicitly appended. This pattern + is used to generate a list of matching filenames for possible completions. gglloobb--eexxppaanndd--wwoorrdd ((CC--xx **)) - The word before point is treated as a pattern for pathname - expansion, and the list of matching file names is inserted, - replacing the word. If a numeric argument is supplied, an + The word before point is treated as a pattern for pathname + expansion, and the list of matching filenames is inserted, + replacing the word. If a numeric argument is supplied, an asterisk is appended before pathname expansion. gglloobb--lliisstt--eexxppaannssiioonnss ((CC--xx gg)) - The list of expansions that would have been generated by - gglloobb--eexxppaanndd--wwoorrdd is displayed, and the line is redrawn. If a - numeric argument is supplied, an asterisk is appended before + The list of expansions that would have been generated by + gglloobb--eexxppaanndd--wwoorrdd is displayed, and the line is redrawn. If a + numeric argument is supplied, an asterisk is appended before pathname expansion. dduummpp--ffuunnccttiioonnss - Print all of the functions and their key bindings to the read- + Print all of the functions and their key bindings to the read- line output stream. If a numeric argument is supplied, the out- - put is formatted in such a way that it can be made part of an + put is formatted in such a way that it can be made part of an _i_n_p_u_t_r_c file. dduummpp--vvaarriiaabblleess Print all of the settable readline variables and their values to - the readline output stream. If a numeric argument is supplied, - the output is formatted in such a way that it can be made part + the readline output stream. If a numeric argument is supplied, + the output is formatted in such a way that it can be made part of an _i_n_p_u_t_r_c file. dduummpp--mmaaccrrooss - Print all of the readline key sequences bound to macros and the - strings they output. If a numeric argument is supplied, the + Print all of the readline key sequences bound to macros and the + strings they output. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an _i_n_p_u_t_r_c file. ddiissppllaayy--sshheellll--vveerrssiioonn ((CC--xx CC--vv)) - Display version information about the current instance of bbaasshh. + Display version information about the current instance of bbaasshh. PPrrooggrraammmmaabbllee CCoommpplleettiioonn - When word completion is attempted for an argument to a command for - which a completion specification (a _c_o_m_p_s_p_e_c) has been defined using - the ccoommpplleettee builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the pro- + When word completion is attempted for an argument to a command for + which a completion specification (a _c_o_m_p_s_p_e_c) has been defined using + the ccoommpplleettee builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the pro- grammable completion facilities are invoked. - First, the command name is identified. If the command word is the - empty string (completion attempted at the beginning of an empty line), - any compspec defined with the --EE option to ccoommpplleettee is used. If a - compspec has been defined for that command, the compspec is used to + First, the command name is identified. If the command word is the + empty string (completion attempted at the beginning of an empty line), + any compspec defined with the --EE option to ccoommpplleettee is used. If a + compspec has been defined for that command, the compspec is used to generate the list of possible completions for the word. If the command - word is a full pathname, a compspec for the full pathname is searched - for first. If no compspec is found for the full pathname, an attempt - is made to find a compspec for the portion following the final slash. - If those searches do not result in a compspec, any compspec defined + word is a full pathname, a compspec for the full pathname is searched + for first. If no compspec is found for the full pathname, an attempt + is made to find a compspec for the portion following the final slash. + If those searches do not result in a compspec, any compspec defined with the --DD option to ccoommpplleettee is used as the default. - Once a compspec has been found, it is used to generate the list of - matching words. If a compspec is not found, the default bbaasshh comple- + Once a compspec has been found, it is used to generate the list of + matching words. If a compspec is not found, the default bbaasshh comple- tion as described above under CCoommpplleettiinngg is performed. - First, the actions specified by the compspec are used. Only matches - which are prefixed by the word being completed are returned. When the - --ff or --dd option is used for filename or directory name completion, the + First, the actions specified by the compspec are used. Only matches + which are prefixed by the word being completed are returned. When the + --ff or --dd option is used for filename or directory name completion, the shell variable FFIIGGNNOORREE is used to filter the matches. - Any completions specified by a pathname expansion pattern to the --GG + Any completions specified by a pathname expansion pattern to the --GG option are generated next. The words generated by the pattern need not - match the word being completed. The GGLLOOBBIIGGNNOORREE shell variable is not + match the word being completed. The GGLLOOBBIIGGNNOORREE shell variable is not used to filter the matches, but the FFIIGGNNOORREE variable is used. - Next, the string specified as the argument to the --WW option is consid- - ered. The string is first split using the characters in the IIFFSS spe- - cial variable as delimiters. Shell quoting is honored. Each word is - then expanded using brace expansion, tilde expansion, parameter and - variable expansion, command substitution, and arithmetic expansion, as + Next, the string specified as the argument to the --WW option is consid- + ered. The string is first split using the characters in the IIFFSS spe- + cial variable as delimiters. Shell quoting is honored. Each word is + then expanded using brace expansion, tilde expansion, parameter and + variable expansion, command substitution, and arithmetic expansion, as described above under EEXXPPAANNSSIIOONN. The results are split using the rules described above under WWoorrdd SSpplliittttiinngg. The results of the expansion are prefix-matched against the word being completed, and the matching words become the possible completions. - After these matches have been generated, any shell function or command - specified with the --FF and --CC options is invoked. When the command or + After these matches have been generated, any shell function or command + specified with the --FF and --CC options is invoked. When the command or function is invoked, the CCOOMMPP__LLIINNEE, CCOOMMPP__PPOOIINNTT, CCOOMMPP__KKEEYY, and CCOOMMPP__TTYYPPEE variables are assigned values as described above under SShheellll VVaarriiaabblleess. - If a shell function is being invoked, the CCOOMMPP__WWOORRDDSS and CCOOMMPP__CCWWOORRDD - variables are also set. When the function or command is invoked, the - first argument is the name of the command whose arguments are being - completed, the second argument is the word being completed, and the - third argument is the word preceding the word being completed on the - current command line. No filtering of the generated completions - against the word being completed is performed; the function or command - has complete freedom in generating the matches. - - Any function specified with --FF is invoked first. The function may use - any of the shell facilities, including the ccoommppggeenn builtin described - below, to generate the matches. It must put the possible completions - in the CCOOMMPPRREEPPLLYY array variable. - - Next, any command specified with the --CC option is invoked in an envi- - ronment equivalent to command substitution. It should print a list of - completions, one per line, to the standard output. Backslash may be + If a shell function is being invoked, the CCOOMMPP__WWOORRDDSS and CCOOMMPP__CCWWOORRDD + variables are also set. When the function or command is invoked, the + first argument ($$11) is the name of the command whose arguments are + being completed, the second argument ($$22) is the word being completed, + and the third argument ($$33) is the word preceding the word being com- + pleted on the current command line. No filtering of the generated com- + pletions against the word being completed is performed; the function or + command has complete freedom in generating the matches. + + Any function specified with --FF is invoked first. The function may use + any of the shell facilities, including the ccoommppggeenn builtin described + below, to generate the matches. It must put the possible completions + in the CCOOMMPPRREEPPLLYY array variable, one per array element. + + Next, any command specified with the --CC option is invoked in an envi- + ronment equivalent to command substitution. It should print a list of + completions, one per line, to the standard output. Backslash may be used to escape a newline, if necessary. - After all of the possible completions are generated, any filter speci- - fied with the --XX option is applied to the list. The filter is a pat- - tern as used for pathname expansion; a && in the pattern is replaced - with the text of the word being completed. A literal && may be escaped - with a backslash; the backslash is removed before attempting a match. - Any completion that matches the pattern will be removed from the list. + After all of the possible completions are generated, any filter speci- + fied with the --XX option is applied to the list. The filter is a pat- + tern as used for pathname expansion; a && in the pattern is replaced + with the text of the word being completed. A literal && may be escaped + with a backslash; the backslash is removed before attempting a match. + Any completion that matches the pattern will be removed from the list. A leading !! negates the pattern; in this case any completion not match- ing the pattern will be removed. @@ -3516,83 +3652,86 @@ RREEAADDLLIINNEE added to each member of the completion list, and the result is returned to the readline completion code as the list of possible completions. - If the previously-applied actions do not generate any matches, and the - --oo ddiirrnnaammeess option was supplied to ccoommpplleettee when the compspec was + If the previously-applied actions do not generate any matches, and the + --oo ddiirrnnaammeess option was supplied to ccoommpplleettee when the compspec was defined, directory name completion is attempted. - If the --oo pplluussddiirrss option was supplied to ccoommpplleettee when the compspec + If the --oo pplluussddiirrss option was supplied to ccoommpplleettee when the compspec was defined, directory name completion is attempted and any matches are added to the results of the other actions. - By default, if a compspec is found, whatever it generates is returned - to the completion code as the full set of possible completions. The + By default, if a compspec is found, whatever it generates is returned + to the completion code as the full set of possible completions. The default bbaasshh completions are not attempted, and the readline default of filename completion is disabled. If the --oo bbaasshhddeeffaauulltt option was sup- - plied to ccoommpplleettee when the compspec was defined, the bbaasshh default com- + plied to ccoommpplleettee when the compspec was defined, the bbaasshh default com- pletions are attempted if the compspec generates no matches. If the --oo - ddeeffaauulltt option was supplied to ccoommpplleettee when the compspec was defined, - readline's default completion will be performed if the compspec (and, + ddeeffaauulltt option was supplied to ccoommpplleettee when the compspec was defined, + readline's default completion will be performed if the compspec (and, if attempted, the default bbaasshh completions) generate no matches. - When a compspec indicates that directory name completion is desired, - the programmable completion functions force readline to append a slash - to completed names which are symbolic links to directories, subject to - the value of the mmaarrkk--ddiirreeccttoorriieess readline variable, regardless of the + When a compspec indicates that directory name completion is desired, + the programmable completion functions force readline to append a slash + to completed names which are symbolic links to directories, subject to + the value of the mmaarrkk--ddiirreeccttoorriieess readline variable, regardless of the setting of the mmaarrkk--ssyymmlliinnkkeedd--ddiirreeccttoorriieess readline variable. - There is some support for dynamically modifying completions. This is - most useful when used in combination with a default completion speci- - fied with ccoommpplleettee --DD. It's possible for shell functions executed as - completion handlers to indicate that completion should be retried by - returning an exit status of 124. If a shell function returns 124, and + There is some support for dynamically modifying completions. This is + most useful when used in combination with a default completion speci- + fied with ccoommpplleettee --DD. It's possible for shell functions executed as + completion handlers to indicate that completion should be retried by + returning an exit status of 124. If a shell function returns 124, and changes the compspec associated with the command on which completion is - being attempted (supplied as the first argument when the function is + being attempted (supplied as the first argument when the function is executed), programmable completion restarts from the beginning, with an - attempt to find a new compspec for that command. This allows a set of - completions to be built dynamically as completion is attempted, rather + attempt to find a new compspec for that command. This allows a set of + completions to be built dynamically as completion is attempted, rather than being loaded all at once. - For instance, assuming that there is a library of compspecs, each kept - in a file corresponding to the name of the command, the following + For instance, assuming that there is a library of compspecs, each kept + in a file corresponding to the name of the command, the following default completion function would load completions dynamically: _completion_loader() { . "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124 } - complete -D -F _completion_loader + complete -D -F _completion_loader -o bashdefault -o default HHIISSTTOORRYY - When the --oo hhiissttoorryy option to the sseett builtin is enabled, the shell + When the --oo hhiissttoorryy option to the sseett builtin is enabled, the shell provides access to the _c_o_m_m_a_n_d _h_i_s_t_o_r_y, the list of commands previously - typed. The value of the HHIISSTTSSIIZZEE variable is used as the number of + typed. The value of the HHIISSTTSSIIZZEE variable is used as the number of commands to save in a history list. The text of the last HHIISSTTSSIIZZEE com- - mands (default 500) is saved. The shell stores each command in the - history list prior to parameter and variable expansion (see EEXXPPAANNSSIIOONN - above) but after history expansion is performed, subject to the values + mands (default 500) is saved. The shell stores each command in the + history list prior to parameter and variable expansion (see EEXXPPAANNSSIIOONN + above) but after history expansion is performed, subject to the values of the shell variables HHIISSTTIIGGNNOORREE and HHIISSTTCCOONNTTRROOLL. On startup, the history is initialized from the file named by the vari- - able HHIISSTTFFIILLEE (default _~_/_._b_a_s_h___h_i_s_t_o_r_y). The file named by the value - of HHIISSTTFFIILLEE is truncated, if necessary, to contain no more than the - number of lines specified by the value of HHIISSTTFFIILLEESSIIZZEE. When the his- - tory file is read, lines beginning with the history comment character - followed immediately by a digit are interpreted as timestamps for the - preceding history line. These timestamps are optionally displayed - depending on the value of the HHIISSTTTTIIMMEEFFOORRMMAATT variable. When an inter- - active shell exits, the last $$HHIISSTTSSIIZZEE lines are copied from the his- - tory list to $$HHIISSTTFFIILLEE. If the hhiissttaappppeenndd shell option is enabled (see - the description of sshhoopptt under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the lines - are appended to the history file, otherwise the history file is over- - written. If HHIISSTTFFIILLEE is unset, or if the history file is unwritable, - the history is not saved. If the HHIISSTTTTIIMMEEFFOORRMMAATT variable is set, time - stamps are written to the history file, marked with the history comment - character, so they may be preserved across shell sessions. This uses - the history comment character to distinguish timestamps from other his- - tory lines. After saving the history, the history file is truncated to - contain no more than HHIISSTTFFIILLEESSIIZZEE lines. If HHIISSTTFFIILLEESSIIZZEE is not set, - no truncation is performed. + able HHIISSTTFFIILLEE (default _~_/_._b_a_s_h___h_i_s_t_o_r_y). The file named by the value + of HHIISSTTFFIILLEE is truncated, if necessary, to contain no more than the + number of lines specified by the value of HHIISSTTFFIILLEESSIIZZEE. If HHIISSTTFFIILLEE-- + SSIIZZEE is unset, or set to null, a non-numeric value, or a numeric value + less than zero, the history file is not truncated. When the history + file is read, lines beginning with the history comment character fol- + lowed immediately by a digit are interpreted as timestamps for the pre- + ceding history line. These timestamps are optionally displayed depend- + ing on the value of the HHIISSTTTTIIMMEEFFOORRMMAATT variable. When a shell with + history enabled exits, the last $$HHIISSTTSSIIZZEE lines are copied from the + history list to $$HHIISSTTFFIILLEE. If the hhiissttaappppeenndd shell option is enabled + (see the description of sshhoopptt under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the + lines are appended to the history file, otherwise the history file is + overwritten. If HHIISSTTFFIILLEE is unset, or if the history file is + unwritable, the history is not saved. If the HHIISSTTTTIIMMEEFFOORRMMAATT variable + is set, time stamps are written to the history file, marked with the + history comment character, so they may be preserved across shell ses- + sions. This uses the history comment character to distinguish time- + stamps from other history lines. After saving the history, the history + file is truncated to contain no more than HHIISSTTFFIILLEESSIIZZEE lines. If HHIISSTT-- + FFIILLEESSIIZZEE is unset, or set to null, a non-numeric value, or a numeric + value less than zero, the history file is not truncated. The builtin command ffcc (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below) may be used to list or edit and re-execute a portion of the history list. The hhiiss-- @@ -3678,7 +3817,7 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN Refer to the most recent command preceding the current position in the history list starting with _s_t_r_i_n_g. !!??_s_t_r_i_n_g[[??]] - Refer to the most recent command preceding the current postition + Refer to the most recent command preceding the current position in the history list containing _s_t_r_i_n_g. The trailing ?? may be omitted if _s_t_r_i_n_g is followed immediately by a newline. ^^_s_t_r_i_n_g_1^^_s_t_r_i_n_g_2^^ @@ -3699,7 +3838,8 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN The zeroth word. For the shell, this is the command word. _n The _nth word. ^^ The first argument. That is, word 1. - $$ The last argument. + $$ The last word. This is usually the last argument, but will + expand to the zeroth word if there is only one word in the line. %% The word matched by the most recent `?_s_t_r_i_n_g?' search. _x--_y A range of words; `-_y' abbreviates `0-_y'. ** All of the words but the zeroth. This is a synonym for `_1_-_$'. @@ -3715,8 +3855,8 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN After the optional word designator, there may appear a sequence of one or more of the following modifiers, each preceded by a `:'. - hh Remove a trailing file name component, leaving only the head. - tt Remove all leading file name components, leaving the tail. + hh Remove a trailing filename component, leaving only the head. + tt Remove all leading filename components, leaving the tail. rr Remove a trailing suffix of the form _._x_x_x, leaving the basename. ee Remove all but the trailing suffix. pp Print the new command but do not execute it. @@ -3759,9 +3899,9 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ssoouurrccee _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s] Read and execute commands from _f_i_l_e_n_a_m_e in the current shell environment and return the exit status of the last command exe- - cuted from _f_i_l_e_n_a_m_e. If _f_i_l_e_n_a_m_e does not contain a slash, file - names in PPAATTHH are used to find the directory containing _f_i_l_e_- - _n_a_m_e. The file searched for in PPAATTHH need not be executable. + cuted from _f_i_l_e_n_a_m_e. If _f_i_l_e_n_a_m_e does not contain a slash, + filenames in PPAATTHH are used to find the directory containing + _f_i_l_e_n_a_m_e. The file searched for in PPAATTHH need not be executable. When bbaasshh is not in _p_o_s_i_x _m_o_d_e, the current directory is searched if no file is found in PPAATTHH. If the ssoouurrcceeppaatthh option to the sshhoopptt builtin command is turned off, the PPAATTHH is not @@ -3791,7 +3931,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS enabled, any specified _j_o_b_s_p_e_c was not found or was started without job control. - bbiinndd [--mm _k_e_y_m_a_p] [--llppssvvPPSSVV] + bbiinndd [--mm _k_e_y_m_a_p] [--llppssvvPPSSVVXX] bbiinndd [--mm _k_e_y_m_a_p] [--qq _f_u_n_c_t_i_o_n] [--uu _f_u_n_c_t_i_o_n] [--rr _k_e_y_s_e_q] bbiinndd [--mm _k_e_y_m_a_p] --ff _f_i_l_e_n_a_m_e bbiinndd [--mm _k_e_y_m_a_p] --xx _k_e_y_s_e_q:_s_h_e_l_l_-_c_o_m_m_a_n_d @@ -3838,6 +3978,9 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS command changes the value of RREEAADDLLIINNEE__LLIINNEE or RREEAADD-- LLIINNEE__PPOOIINNTT, those new values will be reflected in the editing state. + --XX List all key sequences bound to shell commands and the + associated commands in a format that can be reused as + input. The return value is 0 unless an unrecognized option is given or an error occurred. @@ -3870,117 +4013,129 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS routine call or _e_x_p_r does not correspond to a valid position in the call stack. - ccdd [--LL|[--PP [--ee]]] [_d_i_r] - Change the current directory to _d_i_r. The variable HHOOMMEE is the - default _d_i_r. The variable CCDDPPAATTHH defines the search path for - the directory containing _d_i_r. Alternative directory names in - CCDDPPAATTHH are separated by a colon (:). A null directory name in - CCDDPPAATTHH is the same as the current directory, i.e., ``..''. If - _d_i_r begins with a slash (/), then CCDDPPAATTHH is not used. The --PP - option says to use the physical directory structure instead of - following symbolic links (see also the --PP option to the sseett - builtin command); the --LL option forces symbolic links to be fol- - lowed. If the --ee option is supplied with --PP, and the current - working directory cannot be successfully determined after a suc- - cessful directory change, ccdd will return an unsuccessful status. - An argument of -- is equivalent to $$OOLLDDPPWWDD. If a non-empty - directory name from CCDDPPAATTHH is used, or if -- is the first argu- - ment, and the directory change is successful, the absolute path- - name of the new working directory is written to the standard - output. The return value is true if the directory was success- - fully changed; false otherwise. + ccdd [--LL|[--PP [--ee]] [-@]] [_d_i_r] + Change the current directory to _d_i_r. if _d_i_r is not supplied, + the value of the HHOOMMEE shell variable is the default. Any addi- + tional arguments following _d_i_r are ignored. The variable CCDDPPAATTHH + defines the search path for the directory containing _d_i_r: each + directory name in CCDDPPAATTHH is searched for _d_i_r. Alternative + directory names in CCDDPPAATTHH are separated by a colon (:). A null + directory name in CCDDPPAATTHH is the same as the current directory, + i.e., ``..''. If _d_i_r begins with a slash (/), then CCDDPPAATTHH is not + used. The --PP option causes ccdd to use the physical directory + structure by resolving symbolic links while traversing _d_i_r and + before processing instances of _._. in _d_i_r (see also the --PP option + to the sseett builtin command); the --LL option forces symbolic links + to be followed by resolving the link after processing instances + of _._. in _d_i_r. If _._. appears in _d_i_r, it is processed by removing + the immediately previous pathname component from _d_i_r, back to a + slash or the beginning of _d_i_r. If the --ee option is supplied + with --PP, and the current working directory cannot be success- + fully determined after a successful directory change, ccdd will + return an unsuccessful status. On systems that support it, the + --@@ option presents the extended attributes associated with a + file as a directory. An argument of -- is converted to $$OOLLDDPPWWDD + before the directory change is attempted. If a non-empty direc- + tory name from CCDDPPAATTHH is used, or if -- is the first argument, + and the directory change is successful, the absolute pathname of + the new working directory is written to the standard output. + The return value is true if the directory was successfully + changed; false otherwise. ccoommmmaanndd [--ppVVvv] _c_o_m_m_a_n_d [_a_r_g ...] - Run _c_o_m_m_a_n_d with _a_r_g_s suppressing the normal shell function - lookup. Only builtin commands or commands found in the PPAATTHH are - executed. If the --pp option is given, the search for _c_o_m_m_a_n_d is - performed using a default value for PPAATTHH that is guaranteed to - find all of the standard utilities. If either the --VV or --vv + Run _c_o_m_m_a_n_d with _a_r_g_s suppressing the normal shell function + lookup. Only builtin commands or commands found in the PPAATTHH are + executed. If the --pp option is given, the search for _c_o_m_m_a_n_d is + performed using a default value for PPAATTHH that is guaranteed to + find all of the standard utilities. If either the --VV or --vv option is supplied, a description of _c_o_m_m_a_n_d is printed. The --vv - option causes a single word indicating the command or file name + option causes a single word indicating the command or filename used to invoke _c_o_m_m_a_n_d to be displayed; the --VV option produces a - more verbose description. If the --VV or --vv option is supplied, - the exit status is 0 if _c_o_m_m_a_n_d was found, and 1 if not. If + more verbose description. If the --VV or --vv option is supplied, + the exit status is 0 if _c_o_m_m_a_n_d was found, and 1 if not. If neither option is supplied and an error occurred or _c_o_m_m_a_n_d can- - not be found, the exit status is 127. Otherwise, the exit sta- + not be found, the exit status is 127. Otherwise, the exit sta- tus of the ccoommmmaanndd builtin is the exit status of _c_o_m_m_a_n_d. ccoommppggeenn [_o_p_t_i_o_n] [_w_o_r_d] - Generate possible completion matches for _w_o_r_d according to the - _o_p_t_i_o_ns, which may be any option accepted by the ccoommpplleettee - builtin with the exception of --pp and --rr, and write the matches - to the standard output. When using the --FF or --CC options, the - various shell variables set by the programmable completion + Generate possible completion matches for _w_o_r_d according to the + _o_p_t_i_o_ns, which may be any option accepted by the ccoommpplleettee + builtin with the exception of --pp and --rr, and write the matches + to the standard output. When using the --FF or --CC options, the + various shell variables set by the programmable completion facilities, while available, will not have useful values. - The matches will be generated in the same way as if the pro- - grammable completion code had generated them directly from a + The matches will be generated in the same way as if the pro- + grammable completion code had generated them directly from a completion specification with the same flags. If _w_o_r_d is speci- fied, only those completions matching _w_o_r_d will be displayed. - The return value is true unless an invalid option is supplied, + The return value is true unless an invalid option is supplied, or no matches were generated. - ccoommpplleettee [--aabbccddeeffggjjkkssuuvv] [--oo _c_o_m_p_-_o_p_t_i_o_n] [--DDEE] [--AA _a_c_t_i_o_n] [--GG _g_l_o_b_- + ccoommpplleettee [--aabbccddeeffggjjkkssuuvv] [--oo _c_o_m_p_-_o_p_t_i_o_n] [--DDEE] [--AA _a_c_t_i_o_n] [--GG _g_l_o_b_- _p_a_t] [--WW _w_o_r_d_l_i_s_t] [--FF _f_u_n_c_t_i_o_n] [--CC _c_o_m_m_a_n_d] [--XX _f_i_l_t_e_r_p_a_t] [--PP _p_r_e_f_i_x] [--SS _s_u_f_f_i_x] _n_a_m_e [_n_a_m_e _._._.] ccoommpplleettee --pprr [--DDEE] [_n_a_m_e ...] - Specify how arguments to each _n_a_m_e should be completed. If the - --pp option is supplied, or if no options are supplied, existing - completion specifications are printed in a way that allows them + Specify how arguments to each _n_a_m_e should be completed. If the + --pp option is supplied, or if no options are supplied, existing + completion specifications are printed in a way that allows them to be reused as input. The --rr option removes a completion spec- - ification for each _n_a_m_e, or, if no _n_a_m_es are supplied, all com- + ification for each _n_a_m_e, or, if no _n_a_m_es are supplied, all com- pletion specifications. The --DD option indicates that the - remaining options and actions should apply to the ``default'' - command completion; that is, completion attempted on a command - for which no completion has previously been defined. The --EE - option indicates that the remaining options and actions should - apply to ``empty'' command completion; that is, completion + remaining options and actions should apply to the ``default'' + command completion; that is, completion attempted on a command + for which no completion has previously been defined. The --EE + option indicates that the remaining options and actions should + apply to ``empty'' command completion; that is, completion attempted on a blank line. - The process of applying these completion specifications when - word completion is attempted is described above under PPrroo-- + The process of applying these completion specifications when + word completion is attempted is described above under PPrroo-- ggrraammmmaabbllee CCoommpplleettiioonn. - Other options, if specified, have the following meanings. The - arguments to the --GG, --WW, and --XX options (and, if necessary, the - --PP and --SS options) should be quoted to protect them from expan- + Other options, if specified, have the following meanings. The + arguments to the --GG, --WW, and --XX options (and, if necessary, the + --PP and --SS options) should be quoted to protect them from expan- sion before the ccoommpplleettee builtin is invoked. --oo _c_o_m_p_-_o_p_t_i_o_n - The _c_o_m_p_-_o_p_t_i_o_n controls several aspects of the comp- - spec's behavior beyond the simple generation of comple- + The _c_o_m_p_-_o_p_t_i_o_n controls several aspects of the comp- + spec's behavior beyond the simple generation of comple- tions. _c_o_m_p_-_o_p_t_i_o_n may be one of: bbaasshhddeeffaauulltt Perform the rest of the default bbaasshh completions if the compspec generates no matches. - ddeeffaauulltt Use readline's default filename completion if + ddeeffaauulltt Use readline's default filename completion if the compspec generates no matches. ddiirrnnaammeess - Perform directory name completion if the comp- + Perform directory name completion if the comp- spec generates no matches. ffiilleennaammeess - Tell readline that the compspec generates file- - names, so it can perform any filename-specific - processing (like adding a slash to directory - names, quoting special characters, or suppress- - ing trailing spaces). Intended to be used with + Tell readline that the compspec generates file- + names, so it can perform any filename-specific + processing (like adding a slash to directory + names, quoting special characters, or suppress- + ing trailing spaces). Intended to be used with shell functions. - nnoossppaaccee Tell readline not to append a space (the - default) to words completed at the end of the + nnooqquuoottee Tell readline not to quote the completed words + if they are filenames (quoting filenames is the + default). + nnoossppaaccee Tell readline not to append a space (the + default) to words completed at the end of the line. pplluussddiirrss - After any matches defined by the compspec are - generated, directory name completion is - attempted and any matches are added to the + After any matches defined by the compspec are + generated, directory name completion is + attempted and any matches are added to the results of the other actions. --AA _a_c_t_i_o_n - The _a_c_t_i_o_n may be one of the following to generate a + The _a_c_t_i_o_n may be one of the following to generate a list of possible completions: aalliiaass Alias names. May also be specified as --aa. aarrrraayyvvaarr Array variable names. bbiinnddiinngg RReeaaddlliinnee key binding names. - bbuuiillttiinn Names of shell builtin commands. May also be + bbuuiillttiinn Names of shell builtin commands. May also be specified as --bb. ccoommmmaanndd Command names. May also be specified as --cc. ddiirreeccttoorryy @@ -3988,7 +4143,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ddiissaabblleedd Names of disabled shell builtins. eennaabblleedd Names of enabled shell builtins. - eexxppoorrtt Names of exported shell variables. May also be + eexxppoorrtt Names of exported shell variables. May also be specified as --ee. ffiillee File names. May also be specified as --ff. ffuunnccttiioonn @@ -3997,17 +4152,17 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS hheellppttooppiicc Help topics as accepted by the hheellpp builtin. hhoossttnnaammee - Hostnames, as taken from the file specified by + Hostnames, as taken from the file specified by the HHOOSSTTFFIILLEE shell variable. - jjoobb Job names, if job control is active. May also + jjoobb Job names, if job control is active. May also be specified as --jj. - kkeeyywwoorrdd Shell reserved words. May also be specified as + kkeeyywwoorrdd Shell reserved words. May also be specified as --kk. rruunnnniinngg Names of running jobs, if job control is active. sseerrvviiccee Service names. May also be specified as --ss. - sseettoopptt Valid arguments for the --oo option to the sseett + sseettoopptt Valid arguments for the --oo option to the sseett builtin. - sshhoopptt Shell option names as accepted by the sshhoopptt + sshhoopptt Shell option names as accepted by the sshhoopptt builtin. ssiiggnnaall Signal names. ssttooppppeedd Names of stopped jobs, if job control is active. @@ -4016,13 +4171,18 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS Names of all shell variables. May also be spec- ified as --vv. --CC _c_o_m_m_a_n_d - _c_o_m_m_a_n_d is executed in a subshell environment, and its + _c_o_m_m_a_n_d is executed in a subshell environment, and its output is used as the possible completions. --FF _f_u_n_c_t_i_o_n - The shell function _f_u_n_c_t_i_o_n is executed in the current - shell environment. When it finishes, the possible com- - pletions are retrieved from the value of the CCOOMMPPRREEPPLLYY - array variable. + The shell function _f_u_n_c_t_i_o_n is executed in the current + shell environment. When the function is executed, the + first argument ($$11) is the name of the command whose + arguments are being completed, the second argument ($$22) + is the word being completed, and the third argument ($$33) + is the word preceding the word being completed on the + current command line. When it finishes, the possible + completions are retrieved from the value of the CCOOMMPPRREE-- + PPLLYY array variable. --GG _g_l_o_b_p_a_t The pathname expansion pattern _g_l_o_b_p_a_t is expanded to generate the possible completions. @@ -4077,27 +4237,27 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS loop) is resumed. The return value is 0 unless _n is not greater than or equal to 1. - ddeeccllaarree [--aaAAffFFggiillrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] - ttyyppeesseett [--aaAAffFFggiillrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] + ddeeccllaarree [--aaAAffFFggiillnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] + ttyyppeesseett [--aaAAffFFggiillnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] Declare variables and/or give them attributes. If no _n_a_m_es are given then display the values of variables. The --pp option will display the attributes and values of each _n_a_m_e. When --pp is used - with _n_a_m_e arguments, additional options are ignored. When --pp is - supplied without _n_a_m_e arguments, it will display the attributes - and values of all variables having the attributes specified by - the additional options. If no other options are supplied with - --pp, ddeeccllaarree will display the attributes and values of all shell - variables. The --ff option will restrict the display to shell - functions. The --FF option inhibits the display of function defi- - nitions; only the function name and attributes are printed. If - the eexxttddeebbuugg shell option is enabled using sshhoopptt, the source - file name and line number where the function is defined are dis- - played as well. The --FF option implies --ff. The --gg option forces - variables to be created or modified at the global scope, even - when ddeeccllaarree is executed in a shell function. It is ignored in - all other cases. The following options can be used to restrict - output to variables with the specified attribute or to give - variables attributes: + with _n_a_m_e arguments, additional options, other than --ff and --FF, + are ignored. When --pp is supplied without _n_a_m_e arguments, it + will display the attributes and values of all variables having + the attributes specified by the additional options. If no other + options are supplied with --pp, ddeeccllaarree will display the + attributes and values of all shell variables. The --ff option + will restrict the display to shell functions. The --FF option + inhibits the display of function definitions; only the function + name and attributes are printed. If the eexxttddeebbuugg shell option + is enabled using sshhoopptt, the source file name and line number + where the function is defined are displayed as well. The --FF + option implies --ff. The --gg option forces variables to be created + or modified at the global scope, even when ddeeccllaarree is executed + in a shell function. It is ignored in all other cases. The + following options can be used to restrict output to variables + with the specified attribute or to give variables attributes: --aa Each _n_a_m_e is an indexed array variable (see AArrrraayyss above). --AA Each _n_a_m_e is an associative array variable (see AArrrraayyss @@ -4109,6 +4269,13 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --ll When the variable is assigned a value, all upper-case characters are converted to lower-case. The upper-case attribute is disabled. + --nn Give each _n_a_m_e the _n_a_m_e_r_e_f attribute, making it a name + reference to another variable. That other variable is + defined by the value of _n_a_m_e. All references and assign- + ments to _n_a_m_e, except for changing the --nn attribute + itself, are performed on the variable referenced by + _n_a_m_e's value. The --nn attribute cannot be applied to + array variables. --rr Make _n_a_m_es readonly. These names cannot then be assigned values by subsequent assignment statements or unset. --tt Give each _n_a_m_e the _t_r_a_c_e attribute. Traced functions @@ -4124,66 +4291,68 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS Using `+' instead of `-' turns off the attribute instead, with the exceptions that ++aa may not be used to destroy an array vari- able and ++rr will not remove the readonly attribute. When used - in a function, makes each _n_a_m_e local, as with the llooccaall command, - unless the --ggPP ooppttiioonn iiss ssuupppplliieedd,, IIff aa vvaarriiaabbllee nnaammee iiss ffooll-- - lloowweedd bbyy ==_v_a_l_u_e,, tthhee vvaalluuee ooff tthhee vvaarriiaabbllee iiss sseett ttoo _v_a_l_u_e.. TThhee - rreettuurrnn vvaalluuee iiss 00 uunnlleessss aann iinnvvaalliidd ooppttiioonn iiss eennccoouunntteerreedd,, aann - aatttteemmpptt iiss mmaaddee ttoo ddeeffiinnee aa ffuunnccttiioonn uussiinngg ````--ff ffoooo==bbaarr'''',, aann - aatttteemmpptt iiss mmaaddee ttoo aassssiiggnn aa vvaalluuee ttoo aa rreeaaddoonnllyy vvaarriiaabbllee,, aann - aatttteemmpptt iiss mmaaddee ttoo aassssiiggnn aa vvaalluuee ttoo aann aarrrraayy vvaarriiaabbllee wwiitthhoouutt - uussiinngg tthhee ccoommppoouunndd aassssiiggnnmmeenntt ssyynnttaaxx ((sseeee AArrrraayyss above), one of - the _n_a_m_e_s is not a valid shell variable name, an attempt is made - to turn off readonly status for a readonly variable, an attempt - is made to turn off array status for an array variable, or an - attempt is made to display a non-existent function with --ff. - - ddiirrss [[++_n]] [[--_n]] [[--ccllppvv]] - Without options, displays the list of currently remembered - directories. The default display is on a single line with - directory names separated by spaces. Directories are added to - the list with the ppuusshhdd command; the ppooppdd command removes + in a function, ddeeccllaarree and ttyyppeesseett make each _n_a_m_e local, as with + the llooccaall command, unless the --gg option is supplied. If a vari- + able name is followed by =_v_a_l_u_e, the value of the variable is + set to _v_a_l_u_e. When using --aa or --AA and the compound assignment + syntax to create array variables, additional attributes do not + take effect until subsequent assignments. The return value is 0 + unless an invalid option is encountered, an attempt is made to + define a function using ``-f foo=bar'', an attempt is made to + assign a value to a readonly variable, an attempt is made to + assign a value to an array variable without using the compound + assignment syntax (see AArrrraayyss above), one of the _n_a_m_e_s is not a + valid shell variable name, an attempt is made to turn off read- + only status for a readonly variable, an attempt is made to turn + off array status for an array variable, or an attempt is made to + display a non-existent function with --ff. + + ddiirrss [[--ccllppvv]] [[++_n]] [[--_n]] + Without options, displays the list of currently remembered + directories. The default display is on a single line with + directory names separated by spaces. Directories are added to + the list with the ppuusshhdd command; the ppooppdd command removes entries from the list. - ++_n Displays the _nth entry counting from the left of the list - shown by ddiirrss when invoked without options, starting with - zero. - --_n Displays the _nth entry counting from the right of the - list shown by ddiirrss when invoked without options, starting - with zero. --cc Clears the directory stack by deleting all of the entries. - --ll Produces a longer listing; the default listing format - uses a tilde to denote the home directory. + --ll Produces a listing using full pathnames; the default + listing format uses a tilde to denote the home directory. --pp Print the directory stack with one entry per line. --vv Print the directory stack with one entry per line, pre- fixing each entry with its index in the stack. + ++_n Displays the _nth entry counting from the left of the list + shown by ddiirrss when invoked without options, starting with + zero. + --_n Displays the _nth entry counting from the right of the + list shown by ddiirrss when invoked without options, starting + with zero. The return value is 0 unless an invalid option is supplied or _n indexes beyond the end of the directory stack. ddiissoowwnn [--aarr] [--hh] [_j_o_b_s_p_e_c ...] - Without options, each _j_o_b_s_p_e_c is removed from the table of - active jobs. If _j_o_b_s_p_e_c is not present, and neither --aa nor --rr - is supplied, the shell's notion of the _c_u_r_r_e_n_t _j_o_b is used. If - the --hh option is given, each _j_o_b_s_p_e_c is not removed from the ta- - ble, but is marked so that SSIIGGHHUUPP is not sent to the job if the - shell receives a SSIIGGHHUUPP. If no _j_o_b_s_p_e_c is present, and neither - the --aa nor the --rr option is supplied, the _c_u_r_r_e_n_t _j_o_b is used. - If no _j_o_b_s_p_e_c is supplied, the --aa option means to remove or mark - all jobs; the --rr option without a _j_o_b_s_p_e_c argument restricts - operation to running jobs. The return value is 0 unless a _j_o_b_- - _s_p_e_c does not specify a valid job. + Without options, remove each _j_o_b_s_p_e_c from the table of active + jobs. If _j_o_b_s_p_e_c is not present, and neither the --aa nor the --rr + option is supplied, the _c_u_r_r_e_n_t _j_o_b is used. If the --hh option + is given, each _j_o_b_s_p_e_c is not removed from the table, but is + marked so that SSIIGGHHUUPP is not sent to the job if the shell + receives a SSIIGGHHUUPP. If no _j_o_b_s_p_e_c is supplied, the --aa option + means to remove or mark all jobs; the --rr option without a _j_o_b_- + _s_p_e_c argument restricts operation to running jobs. The return + value is 0 unless a _j_o_b_s_p_e_c does not specify a valid job. eecchhoo [--nneeEE] [_a_r_g ...] Output the _a_r_gs, separated by spaces, followed by a newline. - The return status is always 0. If --nn is specified, the trailing - newline is suppressed. If the --ee option is given, interpreta- - tion of the following backslash-escaped characters is enabled. - The --EE option disables the interpretation of these escape char- - acters, even on systems where they are interpreted by default. - The xxppgg__eecchhoo shell option may be used to dynamically determine - whether or not eecchhoo expands these escape characters by default. - eecchhoo does not interpret ---- to mean the end of options. eecchhoo - interprets the following escape sequences: + The return status is 0 unless a write error occurs. If --nn is + specified, the trailing newline is suppressed. If the --ee option + is given, interpretation of the following backslash-escaped + characters is enabled. The --EE option disables the interpreta- + tion of these escape characters, even on systems where they are + interpreted by default. The xxppgg__eecchhoo shell option may be used + to dynamically determine whether or not eecchhoo expands these + escape characters by default. eecchhoo does not interpret ---- to + mean the end of options. eecchhoo interprets the following escape + sequences: \\aa alert (bell) \\bb backspace \\cc suppress further output @@ -4195,89 +4364,88 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS \\tt horizontal tab \\vv vertical tab \\\\ backslash - \\00_n_n_n the eight-bit character whose value is the octal value + \\00_n_n_n the eight-bit character whose value is the octal value _n_n_n (zero to three octal digits) - \\xx_H_H the eight-bit character whose value is the hexadecimal + \\xx_H_H the eight-bit character whose value is the hexadecimal value _H_H (one or two hex digits) - \\uu_H_H_H_H the Unicode (ISO/IEC 10646) character whose value is the + \\uu_H_H_H_H the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value _H_H_H_H (one to four hex digits) \\UU_H_H_H_H_H_H_H_H - the Unicode (ISO/IEC 10646) character whose value is the + the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value _H_H_H_H_H_H_H_H (one to eight hex digits) eennaabbllee [--aa] [--ddnnppss] [--ff _f_i_l_e_n_a_m_e] [_n_a_m_e ...] - Enable and disable builtin shell commands. Disabling a builtin + Enable and disable builtin shell commands. Disabling a builtin allows a disk command which has the same name as a shell builtin - to be executed without specifying a full pathname, even though - the shell normally searches for builtins before disk commands. - If --nn is used, each _n_a_m_e is disabled; otherwise, _n_a_m_e_s are + to be executed without specifying a full pathname, even though + the shell normally searches for builtins before disk commands. + If --nn is used, each _n_a_m_e is disabled; otherwise, _n_a_m_e_s are enabled. For example, to use the tteesstt binary found via the PPAATTHH - instead of the shell builtin version, run ``enable -n test''. - The --ff option means to load the new builtin command _n_a_m_e from + instead of the shell builtin version, run ``enable -n test''. + The --ff option means to load the new builtin command _n_a_m_e from shared object _f_i_l_e_n_a_m_e, on systems that support dynamic loading. - The --dd option will delete a builtin previously loaded with --ff. + The --dd option will delete a builtin previously loaded with --ff. If no _n_a_m_e arguments are given, or if the --pp option is supplied, a list of shell builtins is printed. With no other option argu- - ments, the list consists of all enabled shell builtins. If --nn - is supplied, only disabled builtins are printed. If --aa is sup- - plied, the list printed includes all builtins, with an indica- - tion of whether or not each is enabled. If --ss is supplied, the - output is restricted to the POSIX _s_p_e_c_i_a_l builtins. The return - value is 0 unless a _n_a_m_e is not a shell builtin or there is an + ments, the list consists of all enabled shell builtins. If --nn + is supplied, only disabled builtins are printed. If --aa is sup- + plied, the list printed includes all builtins, with an indica- + tion of whether or not each is enabled. If --ss is supplied, the + output is restricted to the POSIX _s_p_e_c_i_a_l builtins. The return + value is 0 unless a _n_a_m_e is not a shell builtin or there is an error loading a new builtin from a shared object. eevvaall [_a_r_g ...] - The _a_r_gs are read and concatenated together into a single com- - mand. This command is then read and executed by the shell, and - its exit status is returned as the value of eevvaall. If there are + The _a_r_gs are read and concatenated together into a single com- + mand. This command is then read and executed by the shell, and + its exit status is returned as the value of eevvaall. If there are no _a_r_g_s, or only null arguments, eevvaall returns 0. eexxeecc [--ccll] [--aa _n_a_m_e] [_c_o_m_m_a_n_d [_a_r_g_u_m_e_n_t_s]] - If _c_o_m_m_a_n_d is specified, it replaces the shell. No new process - is created. The _a_r_g_u_m_e_n_t_s become the arguments to _c_o_m_m_a_n_d. If + If _c_o_m_m_a_n_d is specified, it replaces the shell. No new process + is created. The _a_r_g_u_m_e_n_t_s become the arguments to _c_o_m_m_a_n_d. If the --ll option is supplied, the shell places a dash at the begin- - ning of the zeroth argument passed to _c_o_m_m_a_n_d. This is what + ning of the zeroth argument passed to _c_o_m_m_a_n_d. This is what _l_o_g_i_n(1) does. The --cc option causes _c_o_m_m_a_n_d to be executed with - an empty environment. If --aa is supplied, the shell passes _n_a_m_e + an empty environment. If --aa is supplied, the shell passes _n_a_m_e as the zeroth argument to the executed command. If _c_o_m_m_a_n_d can- - not be executed for some reason, a non-interactive shell exits, - unless the shell option eexxeeccffaaiill is enabled, in which case it - returns failure. An interactive shell returns failure if the + not be executed for some reason, a non-interactive shell exits, + unless the eexxeeccffaaiill shell option is enabled. In that case, it + returns failure. An interactive shell returns failure if the file cannot be executed. If _c_o_m_m_a_n_d is not specified, any redi- rections take effect in the current shell, and the return status - is 0. If there is a redirection error, the return status is 1. + is 0. If there is a redirection error, the return status is 1. eexxiitt [_n] - Cause the shell to exit with a status of _n. If _n is omitted, + Cause the shell to exit with a status of _n. If _n is omitted, the exit status is that of the last command executed. A trap on EEXXIITT is executed before the shell terminates. eexxppoorrtt [--ffnn] [_n_a_m_e[=_w_o_r_d]] ... eexxppoorrtt --pp - The supplied _n_a_m_e_s are marked for automatic export to the envi- - ronment of subsequently executed commands. If the --ff option is - given, the _n_a_m_e_s refer to functions. If no _n_a_m_e_s are given, or - if the --pp option is supplied, a list of all names that are - exported in this shell is printed. The --nn option causes the - export property to be removed from each _n_a_m_e. If a variable - name is followed by =_w_o_r_d, the value of the variable is set to - _w_o_r_d. eexxppoorrtt returns an exit status of 0 unless an invalid - option is encountered, one of the _n_a_m_e_s is not a valid shell - variable name, or --ff is supplied with a _n_a_m_e that is not a func- - tion. + The supplied _n_a_m_e_s are marked for automatic export to the envi- + ronment of subsequently executed commands. If the --ff option is + given, the _n_a_m_e_s refer to functions. If no _n_a_m_e_s are given, or + if the --pp option is supplied, a list of names of all exported + variables is printed. The --nn option causes the export property + to be removed from each _n_a_m_e. If a variable name is followed by + =_w_o_r_d, the value of the variable is set to _w_o_r_d. eexxppoorrtt returns + an exit status of 0 unless an invalid option is encountered, one + of the _n_a_m_e_s is not a valid shell variable name, or --ff is sup- + plied with a _n_a_m_e that is not a function. ffcc [--ee _e_n_a_m_e] [--llnnrr] [_f_i_r_s_t] [_l_a_s_t] ffcc --ss [_p_a_t=_r_e_p] [_c_m_d] - Fix Command. In the first form, a range of commands from _f_i_r_s_t - to _l_a_s_t is selected from the history list. _F_i_r_s_t and _l_a_s_t may - be specified as a string (to locate the last command beginning - with that string) or as a number (an index into the history - list, where a negative number is used as an offset from the cur- - rent command number). If _l_a_s_t is not specified it is set to the - current command for listing (so that ``fc -l -10'' prints the - last 10 commands) and to _f_i_r_s_t otherwise. If _f_i_r_s_t is not spec- - ified it is set to the previous command for editing and -16 for - listing. + The first form selects a range of commands from _f_i_r_s_t to _l_a_s_t + from the history list and displays or edits and re-executes + them. _F_i_r_s_t and _l_a_s_t may be specified as a string (to locate + the last command beginning with that string) or as a number (an + index into the history list, where a negative number is used as + an offset from the current command number). If _l_a_s_t is not + specified it is set to the current command for listing (so that + ``fc -l -10'' prints the last 10 commands) and to _f_i_r_s_t other- + wise. If _f_i_r_s_t is not specified it is set to the previous com- + mand for editing and -16 for listing. The --nn option suppresses the command numbers when listing. The --rr option reverses the order of the commands. If the --ll option @@ -4289,10 +4457,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS plete, the edited commands are echoed and executed. In the second form, _c_o_m_m_a_n_d is re-executed after each instance - of _p_a_t is replaced by _r_e_p. A useful alias to use with this is - ``r="fc -s"'', so that typing ``r cc'' runs the last command - beginning with ``cc'' and typing ``r'' re-executes the last com- - mand. + of _p_a_t is replaced by _r_e_p. _C_o_m_m_a_n_d is intepreted the same as + _f_i_r_s_t above. A useful alias to use with this is ``r="fc -s"'', + so that typing ``r cc'' runs the last command beginning with + ``cc'' and typing ``r'' re-executes the last command. If the first form is used, the return value is 0 unless an invalid option is encountered or _f_i_r_s_t or _l_a_s_t specify history @@ -4338,7 +4506,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ggeettooppttss can report errors in two ways. If the first character of _o_p_t_s_t_r_i_n_g is a colon, _s_i_l_e_n_t error reporting is used. In - normal operation diagnostic messages are printed when invalid + normal operation, diagnostic messages are printed when invalid options or missing option arguments are encountered. If the variable OOPPTTEERRRR is set to 0, no error messages will be dis- played, even if the first character of _o_p_t_s_t_r_i_n_g is not a colon. @@ -4363,7 +4531,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS is determined by searching the directories in $$PPAATTHH and remem- bered. Any previously-remembered pathname is discarded. If the --pp option is supplied, no path search is performed, and _f_i_l_e_n_a_m_e - is used as the full file name of the command. The --rr option + is used as the full filename of the command. The --rr option causes the shell to forget all remembered locations. The --dd option causes the shell to forget the remembered location of each _n_a_m_e. If the --tt option is supplied, the full pathname to @@ -4384,7 +4552,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --mm Display the description of each _p_a_t_t_e_r_n in a manpage-like format --ss Display only a short usage synopsis for each _p_a_t_t_e_r_n - The return status is 0 unless no command matches _p_a_t_t_e_r_n. + + The return status is 0 unless no command matches _p_a_t_t_e_r_n. hhiissttoorryy [[_n]] hhiissttoorryy --cc @@ -4412,10 +4581,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS file into the current history list. These are lines appended to the history file since the beginning of the current bbaasshh session. - --rr Read the contents of the history file and use them as the - current history. - --ww Write the current history to the history file, overwrit- - ing the history file's contents. + --rr Read the contents of the history file and append them to + the current history list. + --ww Write the current history list to the history file, over- + writing the history file's contents. --pp Perform history substitution on the following _a_r_g_s and display the result on the standard output. Does not store the results in the history list. Each _a_r_g must be @@ -4444,8 +4613,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS status since the user was last notified of their status. --pp List only the process ID of the job's process group leader. - --rr Restrict output to running jobs. - --ss Restrict output to stopped jobs. + --rr Display only running jobs. + --ss Display only stopped jobs. If _j_o_b_s_p_e_c is given, output is restricted to information about that job. The return status is 0 unless an invalid option is @@ -4569,37 +4738,41 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS The corresponding _a_r_g_u_m_e_n_t 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. + -2 represents the time the shell was invoked. If no + argument is specified, conversion behaves as if -1 had + been given. This is an exception to the usual pprriinnttff + behavior. - Arguments to non-string format specifiers are treated as C con- + 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 _f_o_r_m_a_t is reused as necessary to consume all of the _a_r_g_u_- + The _f_o_r_m_a_t is reused as necessary to consume all of the _a_r_g_u_- _m_e_n_t_s. If the _f_o_r_m_a_t requires more _a_r_g_u_m_e_n_t_s than are supplied, - the extra format specifications behave as if a zero value or - null string, as appropriate, had been supplied. The return + the extra format specifications behave as if a zero value or + null string, as appropriate, had been supplied. The return value is zero on success, non-zero on failure. ppuusshhdd [--nn] [+_n] [-_n] ppuusshhdd [--nn] [_d_i_r] - Adds a directory to the top of the directory stack, or rotates - the stack, making the new top of the stack the current working + Adds a directory to the top of the directory stack, or rotates + the stack, making the new top of the stack the current working directory. With no arguments, exchanges the top two directories - and returns 0, unless the directory stack is empty. Arguments, + and returns 0, unless the directory stack is empty. Arguments, if supplied, have the following meanings: - --nn Suppresses the normal change of directory when adding - directories to the stack, so that only the stack is + --nn Suppresses the normal change of directory when adding + directories to the stack, so that only the stack is manipulated. - ++_n Rotates the stack so that the _nth directory (counting - from the left of the list shown by ddiirrss, starting with + ++_n Rotates the stack so that the _nth directory (counting + from the left of the list shown by ddiirrss, starting with zero) is at the top. - --_n Rotates the stack so that the _nth directory (counting - from the right of the list shown by ddiirrss, starting with + --_n Rotates the stack so that the _nth directory (counting + from the right of the list shown by ddiirrss, starting with zero) is at the top. _d_i_r Adds _d_i_r to the directory stack at the top, making it the - new current working directory. + new current working directory as if it had been supplied + as the argument to the ccdd builtin. If the ppuusshhdd command is successful, a ddiirrss is performed as well. If the first form is used, ppuusshhdd returns 0 unless the cd to _d_i_r @@ -4626,128 +4799,149 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ing separators assigned to the last _n_a_m_e. If there are fewer words read from the input stream than names, the remaining names are assigned empty values. The characters in IIFFSS are used to - split the line into words. The backslash character (\\) may be - used to remove any special meaning for the next character read - and for line continuation. Options, if supplied, have the fol- - lowing meanings: + split the line into words using the same rules the shell uses + for expansion (described above under WWoorrdd SSpplliittttiinngg). The back- + slash character (\\) may be used to remove any special meaning + for the next character read and for line continuation. Options, + if supplied, have the following meanings: --aa _a_n_a_m_e The words are assigned to sequential indices of the array variable _a_n_a_m_e, starting at 0. _a_n_a_m_e is unset before any new values are assigned. Other _n_a_m_e arguments are ignored. --dd _d_e_l_i_m - The first character of _d_e_l_i_m is used to terminate the + The first character of _d_e_l_i_m is used to terminate the input line, rather than newline. --ee If the standard input is coming from a terminal, rreeaaddlliinnee - (see RREEAADDLLIINNEE above) is used to obtain the line. Read- - line uses the current (or default, if line editing was + (see RREEAADDLLIINNEE above) is used to obtain the line. Read- + line uses the current (or default, if line editing was not previously active) editing settings. --ii _t_e_x_t - If rreeaaddlliinnee is being used to read the line, _t_e_x_t is + If rreeaaddlliinnee is being used to read the line, _t_e_x_t is placed into the editing buffer before editing begins. --nn _n_c_h_a_r_s - rreeaadd returns after reading _n_c_h_a_r_s characters rather than - waiting for a complete line of input, but honor a delim- - iter if fewer than _n_c_h_a_r_s characters are read before the + rreeaadd returns after reading _n_c_h_a_r_s characters rather than + waiting for a complete line of input, but honor a delim- + iter if fewer than _n_c_h_a_r_s characters are read before the delimiter. --NN _n_c_h_a_r_s - rreeaadd returns after reading exactly _n_c_h_a_r_s characters - rather than waiting for a complete line of input, unless - EOF is encountered or rreeaadd times out. Delimiter charac- - ters encountered in the input are not treated specially - and do not cause rreeaadd to return until _n_c_h_a_r_s characters + rreeaadd returns after reading exactly _n_c_h_a_r_s characters + rather than waiting for a complete line of input, unless + EOF is encountered or rreeaadd times out. Delimiter charac- + ters encountered in the input are not treated specially + and do not cause rreeaadd to return until _n_c_h_a_r_s characters are read. --pp _p_r_o_m_p_t Display _p_r_o_m_p_t on standard error, without a trailing new- line, before attempting to read any input. The prompt is displayed only if input is coming from a terminal. --rr Backslash does not act as an escape character. The back- - slash is considered to be part of the line. In particu- - lar, a backslash-newline pair may not be used as a line + slash is considered to be part of the line. In particu- + lar, a backslash-newline pair may not be used as a line continuation. --ss Silent mode. If input is coming from a terminal, charac- ters are not echoed. --tt _t_i_m_e_o_u_t - Cause rreeaadd to time out and return failure if a complete - line of input is not read within _t_i_m_e_o_u_t seconds. _t_i_m_e_- - _o_u_t may be a decimal number with a fractional portion - following the decimal point. This option is only effec- - tive if rreeaadd is reading input from a terminal, pipe, or - other special file; it has no effect when reading from - regular files. If _t_i_m_e_o_u_t is 0, rreeaadd returns success if - input is available on the specified file descriptor, - failure otherwise. The exit status is greater than 128 - if the timeout is exceeded. + Cause rreeaadd to time out and return failure if a complete + line of input (or a specified number of characters) is + not read within _t_i_m_e_o_u_t seconds. _t_i_m_e_o_u_t may be a deci- + mal number with a fractional portion following the deci- + mal point. This option is only effective if rreeaadd is + reading input from a terminal, pipe, or other special + file; it has no effect when reading from regular files. + If rreeaadd times out, rreeaadd saves any partial input read into + the specified variable _n_a_m_e. If _t_i_m_e_o_u_t is 0, rreeaadd + returns immediately, without trying to read any data. + The exit status is 0 if input is available on the speci- + fied file descriptor, non-zero otherwise. The exit sta- + tus is greater than 128 if the timeout is exceeded. --uu _f_d Read input from file descriptor _f_d. If no _n_a_m_e_s are supplied, the line read is assigned to the vari- able RREEPPLLYY. The return code is zero, unless end-of-file is encountered, rreeaadd times out (in which case the return code is - greater than 128), or an invalid file descriptor is supplied as - the argument to --uu. - - rreeaaddoonnllyy [--aaAAppff] [_n_a_m_e[=_w_o_r_d] ...] - The given _n_a_m_e_s are marked readonly; the values of these _n_a_m_e_s - may not be changed by subsequent assignment. If the --ff option - is supplied, the functions corresponding to the _n_a_m_e_s are so - marked. The --aa option restricts the variables to indexed - arrays; the --AA option restricts the variables to associative - arrays. If no _n_a_m_e arguments are given, or if the --pp option is - supplied, a list of all readonly names is printed. The --pp - option causes output to be displayed in a format that may be - reused as input. If a variable name is followed by =_w_o_r_d, the - value of the variable is set to _w_o_r_d. The return status is 0 - unless an invalid option is encountered, one of the _n_a_m_e_s is not - a valid shell variable name, or --ff is supplied with a _n_a_m_e that - is not a function. + greater than 128), a variable assignment error (such as assign- + ing to a readonly variable) occurs, or an invalid file descrip- + tor is supplied as the argument to --uu. + + rreeaaddoonnllyy [--aaAAff] [--pp] [_n_a_m_e[=_w_o_r_d] ...] + The given _n_a_m_e_s are marked readonly; the values of these _n_a_m_e_s + may not be changed by subsequent assignment. If the --ff option + is supplied, the functions corresponding to the _n_a_m_e_s are so + marked. The --aa option restricts the variables to indexed + arrays; the --AA option restricts the variables to associative + arrays. If both options are supplied, --AA takes precedence. If + no _n_a_m_e arguments are given, or if the --pp 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 --pp option causes output to be displayed in a format + that may be reused as input. If a variable name is followed by + =_w_o_r_d, the value of the variable is set to _w_o_r_d. The return + status is 0 unless an invalid option is encountered, one of the + _n_a_m_e_s is not a valid shell variable name, or --ff is supplied with + a _n_a_m_e that is not a function. rreettuurrnn [_n] - Causes a function to exit with the return value specified by _n. - If _n is omitted, the return status is that of the last command - executed in the function body. If used outside a function, but - during execution of a script by the .. (ssoouurrccee) command, it - causes the shell to stop executing that script and return either - _n or the exit status of the last command executed within the - script as the exit status of the script. If used outside a - function and not during execution of a script by .., the return - status is false. Any command associated with the RREETTUURRNN trap is - executed before execution resumes after the function or script. + Causes a function to stop executing and return the value speci- + fied by _n to its caller. If _n is omitted, the return status is + that of the last command executed in the function body. If + rreettuurrnn is used outside a function, but during execution of a + script by the .. (ssoouurrccee) command, it causes the shell to stop + executing that script and return either _n or the exit status of + the last command executed within the script as the exit status + of the script. If _n is supplied, the return value is its least + significant 8 bits. The return status is non-zero if rreettuurrnn is + supplied a non-numeric argument, or is used outside a function + and not during execution of a script by .. or ssoouurrccee. Any com- + mand associated with the RREETTUURRNN trap is executed before execu- + tion resumes after the function or script. sseett [----aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [--oo _o_p_t_i_o_n_-_n_a_m_e] [_a_r_g ...] sseett [++aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [++oo _o_p_t_i_o_n_-_n_a_m_e] [_a_r_g ...] - Without options, the name and value of each shell variable are + Without options, the name and value of each shell variable are displayed in a format that can be reused as input for setting or resetting the currently-set variables. Read-only variables can- - not be reset. In _p_o_s_i_x _m_o_d_e, only shell variables are listed. - The output is sorted according to the current locale. When - options are specified, they set or unset shell attributes. Any - arguments remaining after option processing are treated as val- + not be reset. In _p_o_s_i_x mode, only shell variables are listed. + The output is sorted according to the current locale. When + options are specified, they set or unset shell attributes. Any + arguments remaining after option processing are treated as val- ues for the positional parameters and are assigned, in order, to - $$11, $$22, ...... $$_n. Options, if specified, have the following + $$11, $$22, ...... $$_n. Options, if specified, have the following meanings: - --aa Automatically mark variables and functions which are - modified or created for export to the environment of + --aa Automatically mark variables and functions which are + modified or created for export to the environment of subsequent commands. - --bb Report the status of terminated background jobs immedi- + --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. - --ee Exit immediately if a _p_i_p_e_l_i_n_e (which may consist of a - single _s_i_m_p_l_e _c_o_m_m_a_n_d), a _s_u_b_s_h_e_l_l command enclosed in - parentheses, or one of the commands executed as part of - a command list enclosed by braces (see SSHHEELLLL GGRRAAMMMMAARR - above) exits with a non-zero status. The shell does not - exit if the command that fails is part of the command - list immediately following a wwhhiillee or uunnttiill keyword, - part of the test following the iiff or eelliiff reserved - words, part of any command executed in a &&&& or |||| list - except the command following the final &&&& or ||||, any - command in a pipeline but the last, or if the command's - return value is being inverted with !!. A trap on EERRRR, + --ee Exit immediately if a _p_i_p_e_l_i_n_e (which may consist of a + single _s_i_m_p_l_e _c_o_m_m_a_n_d), a _l_i_s_t, or a _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d + (see SSHHEELLLL GGRRAAMMMMAARR above), exits with a non-zero sta- + tus. The shell does not exit if the command that fails + is part of the command list immediately following a + wwhhiillee or uunnttiill keyword, part of the test following the + iiff or eelliiff reserved words, part of any command executed + in a &&&& or |||| list except the command following the + final &&&& or ||||, any command in a pipeline but the last, + or if the command's return value is being inverted with + !!. If a compound command other than a subshell returns + a non-zero status because a command failed while --ee was + being ignored, the shell does not exit. A trap on EERRRR, if set, is executed before the shell exits. This option applies to the shell environment and each subshell envi- ronment separately (see CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT above), and may cause subshells to exit before executing all the commands in the subshell. + + If a compound command or shell function executes in a + context where --ee is being ignored, none of the commands + executed within the compound command or function body + will be affected by the --ee setting, even if --ee is set + and a command returns a failure status. If a compound + command or shell function sets --ee while executing in a + context where --ee is ignored, that setting will not have + any effect until the compound command or the command + containing the function call completes. --ff Disable pathname expansion. --hh Remember the location of commands as they are looked up for execution. This is enabled by default. @@ -4756,10 +4950,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS that precede the command name. --mm Monitor mode. Job control is enabled. This option is on by default for interactive shells on systems that - support it (see JJOOBB CCOONNTTRROOLL above). Background pro- - cesses run in a separate process group and a line con- - taining their exit status is printed upon their comple- - tion. + support it (see JJOOBB CCOONNTTRROOLL above). All processes run + in a separate process group. When a background job com- + pletes, the shell prints a line containing its exit sta- + tus. --nn Read commands but do not execute them. This may be used to check a shell script for syntax errors. This is ignored by interactive shells. @@ -4809,7 +5003,9 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS is disabled by default. ppoossiixx Change the behavior of bbaasshh where the default operation differs from the POSIX standard to - match the standard (_p_o_s_i_x _m_o_d_e). + match the standard (_p_o_s_i_x _m_o_d_e). See SSEEEE AALLSSOO + below for a reference to a document that details + how posix mode affects bash's behavior. pprriivviilleeggeedd Same as --pp. vveerrbboossee Same as --vv. @@ -4858,7 +5054,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ited in such cases. --HH Enable !! style history substitution. This option is on by default when the shell is interactive. - --PP If set, the shell does not follow symbolic links when + --PP If set, the shell does not resolve symbolic links when executing commands such as ccdd that change the current working directory. It uses the physical directory structure instead. By default, bbaasshh follows the logical @@ -4894,12 +5090,14 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS zero if _n is greater than $$## or less than zero; otherwise 0. sshhoopptt [--ppqqssuu] [--oo] [_o_p_t_n_a_m_e ...] - Toggle the values of variables controlling optional shell behav- - ior. With no options, or with the --pp option, a list of all set- - table options is displayed, with an indication of whether or not - each is set. The --pp option causes output to be displayed in a - form that may be reused as input. Other options have the fol- - lowing meanings: + Toggle the values of settings controlling optional shell behav- + ior. The settings can be either those listed below, or, if the + --oo option is used, those available with the --oo option to the sseett + builtin command. With no options, or with the --pp option, a list + of all settable options is displayed, with an indication of + whether or not each is set. The --pp option causes output to be + displayed in a form that may be reused as input. Other options + have the following meanings: --ss Enable (set) each _o_p_t_n_a_m_e. --uu Disable (unset) each _o_p_t_n_a_m_e. --qq Suppresses normal output (quiet mode); the return status @@ -4910,10 +5108,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --oo Restricts the values of _o_p_t_n_a_m_e to be those defined for the --oo option to the sseett builtin. - If either --ss or --uu is used with no _o_p_t_n_a_m_e arguments, the dis- - play is limited to those options which are set or unset, respec- - tively. Unless otherwise noted, the sshhoopptt options are disabled - (unset) by default. + If either --ss or --uu is used with no _o_p_t_n_a_m_e arguments, sshhoopptt + shows only those options which are set or unset, respectively. + Unless otherwise noted, the sshhoopptt options are disabled (unset) + by default. The return status when listing options is zero if all _o_p_t_n_a_m_e_s are enabled, non-zero otherwise. When setting or unsetting @@ -4933,7 +5131,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ponent in a ccdd command will be corrected. The errors checked for are transposed characters, a missing charac- ter, and one character too many. If a correction is - found, the corrected file name is printed, and the com- + found, the corrected filename is printed, and the com- mand proceeds. This option is only used by interactive shells. cchheecckkhhaasshh @@ -4958,146 +5156,183 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ccoommppaatt3311 If set, bbaasshh changes its behavior to that of version 3.1 with respect to quoted arguments to the [[[[ conditional - command's ==~~ operator. + command's ==~~ operator and locale-specific string compar- + ison when using the [[[[ conditional command's << and >> + operators. Bash versions prior to bash-4.1 use ASCII + collation and _s_t_r_c_m_p(3); bash-4.1 and later use the cur- + rent locale's collation sequence and _s_t_r_c_o_l_l(3). ccoommppaatt3322 If set, bbaasshh changes its behavior to that of version 3.2 with respect to locale-specific string comparison when - using the [[[[ conditional command's << and >> operators. - Bash versions prior to bash-4.1 use ASCII collation and - _s_t_r_c_m_p(3); bash-4.1 and later use the current locale's - collation sequence and _s_t_r_c_o_l_l(3). + using the [[[[ conditional command's << and >> operators + (see previous item). ccoommppaatt4400 If set, bbaasshh changes its behavior to that of version 4.0 with respect to locale-specific string comparison when using the [[[[ conditional command's << and >> operators - (see previous item) and the effect of interrupting a - command list. + (see description of ccoommppaatt3311) and the effect of inter- + rupting a command list. Bash versions 4.0 and later + interrupt the list as if the shell received the inter- + rupt; previous versions continue with the next command + in the list. ccoommppaatt4411 - @item compat41 If set, bbaasshh, when in posix mode, treats - a single quote in a double-quoted parameter expansion as - a special character. The single quotes must match (an - even number) and the characters between the single - quotes are considered quoted. This is the behavior of - posix mode through version 4.1. The default bash behav- - ior remains as in previous versions. + If set, bbaasshh, when in _p_o_s_i_x mode, treats a single quote + in a double-quoted parameter expansion as a special + character. The single quotes must match (an even num- + ber) and the characters between the single quotes are + considered quoted. This is the behavior of posix mode + through version 4.1. The default bash behavior remains + as in previous versions. + ccoommppaatt4422 + If set, bbaasshh does not process the replacement string in + the pattern substitution word expansion using quote + removal. + ccoommpplleettee__ffuullllqquuoottee + If set, bbaasshh quotes all shell metacharacters in file- + names and directory names when performing completion. + If not set, bbaasshh 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 + expand 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. + ddiirreexxppaanndd + If set, bbaasshh replaces directory names with the results + of word expansion when performing filename completion. + This changes the contents of the readline editing + buffer. If not set, bbaasshh attempts to preserve what the + user typed. ddiirrssppeellll - If set, bbaasshh attempts spelling correction on directory - names during word completion if the directory name ini- + If set, bbaasshh attempts spelling correction on directory + names during word completion if the directory name ini- tially supplied does not exist. - ddoottgglloobb If set, bbaasshh includes filenames beginning with a `.' in + ddoottgglloobb If set, bbaasshh includes filenames beginning with a `.' in the results of pathname expansion. eexxeeccffaaiill If set, a non-interactive shell will not exit if it can- - not execute the file specified as an argument to the - eexxeecc builtin command. An interactive shell does not + not execute the file specified as an argument to the + eexxeecc builtin command. An interactive shell does not exit if eexxeecc fails. eexxppaanndd__aalliiaasseess - If set, aliases are expanded as described above under + If set, aliases are expanded as described above under AALLIIAASSEESS. This option is enabled by default for interac- tive shells. eexxttddeebbuugg - If set, behavior intended for use by debuggers is + If set, behavior intended for use by debuggers is enabled: 11.. The --FF option to the ddeeccllaarree builtin displays the source file name and line number corresponding to each function name supplied as an argument. - 22.. If the command run by the DDEEBBUUGG trap returns a - non-zero value, the next command is skipped and + 22.. If the command run by the DDEEBBUUGG trap returns a + non-zero value, the next command is skipped and not executed. - 33.. If the command run by the DDEEBBUUGG 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 .. or ssoouurrccee builtins), a call to + 33.. If the command run by the DDEEBBUUGG 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 .. or ssoouurrccee builtins), a call to rreettuurrnn is simulated. - 44.. BBAASSHH__AARRGGCC and BBAASSHH__AARRGGVV are updated as described + 44.. BBAASSHH__AARRGGCC and BBAASSHH__AARRGGVV are updated as described in their descriptions above. - 55.. Function tracing is enabled: command substitu- + 55.. Function tracing is enabled: command substitu- tion, shell functions, and subshells invoked with (( _c_o_m_m_a_n_d )) inherit the DDEEBBUUGG and RREETTUURRNN traps. - 66.. Error tracing is enabled: command substitution, - shell functions, and subshells invoked with (( + 66.. Error tracing is enabled: command substitution, + shell functions, and subshells invoked with (( _c_o_m_m_a_n_d )) inherit the EERRRR trap. eexxttgglloobb If set, the extended pattern matching features described above under PPaatthhnnaammee EExxppaannssiioonn are enabled. eexxttqquuoottee - If set, $$'_s_t_r_i_n_g' and $$"_s_t_r_i_n_g" quoting is performed - within $${{_p_a_r_a_m_e_t_e_r}} expansions enclosed in double + If set, $$'_s_t_r_i_n_g' and $$"_s_t_r_i_n_g" quoting is performed + within $${{_p_a_r_a_m_e_t_e_r}} expansions enclosed in double quotes. This option is enabled by default. ffaaiillgglloobb - 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. ffoorrccee__ffiiggnnoorree - If set, the suffixes specified by the FFIIGGNNOORREE shell - variable cause words to be ignored when performing word + If set, the suffixes specified by the FFIIGGNNOORREE shell + variable cause words to be ignored when performing word completion even if the ignored words are the only possi- ble completions. See SSHHEELLLL VVAARRIIAABBLLEESS above for a - description of FFIIGGNNOORREE. This option is enabled by + description of FFIIGGNNOORREE. This option is enabled by default. + gglloobbaasscciiiirraannggeess + If set, range expressions used in pattern matching + bracket expressions (see PPaatttteerrnn MMaattcchhiinngg above) behave + as if in the traditional C locale when performing com- + parisons. That is, the current locale's collating + sequence is not taken into account, so bb will not col- + late between AA and BB, and upper-case and lower-case + ASCII characters will collate together. gglloobbssttaarr If set, the pattern **** used in a pathname expansion con- - text will match a files and zero or more directories and - subdirectories. If the pattern is followed by a //, only - directories and subdirectories match. + text will match all files and zero or more directories + and subdirectories. If the pattern is followed by a //, + only directories and subdirectories match. ggnnuu__eerrrrffmmtt If set, shell error messages are written in the standard GNU error message format. hhiissttaappppeenndd - If set, the history list is appended to the file named - by the value of the HHIISSTTFFIILLEE variable when the shell + If set, the history list is appended to the file named + by the value of the HHIISSTTFFIILLEE variable when the shell exits, rather than overwriting the file. hhiissttrreeeeddiitt - If set, and rreeaaddlliinnee is being used, a user is given the + If set, and rreeaaddlliinnee is being used, a user is given the opportunity to re-edit a failed history substitution. hhiissttvveerriiffyy - If set, and rreeaaddlliinnee 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 rreeaaddlliinnee 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 rreeaaddlliinnee editing buffer, allowing further modi- fication. hhoossttccoommpplleettee If set, and rreeaaddlliinnee is being used, bbaasshh will attempt to - perform hostname completion when a word containing a @@ - is being completed (see CCoommpplleettiinngg under RREEAADDLLIINNEE + perform hostname completion when a word containing a @@ + is being completed (see CCoommpplleettiinngg under RREEAADDLLIINNEE above). This is enabled by default. hhuuppoonneexxiitt If set, bbaasshh will send SSIIGGHHUUPP to all jobs when an inter- active login shell exits. iinntteerraaccttiivvee__ccoommmmeennttss If set, allow a word beginning with ## to cause that word - and all remaining characters on that line to be ignored - in an interactive shell (see CCOOMMMMEENNTTSS above). This + and all remaining characters on that line to be ignored + in an interactive shell (see CCOOMMMMEENNTTSS above). This option is enabled by default. llaassttppiippee - 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. - lliitthhiisstt If set, and the ccmmddhhiisstt option is enabled, multi-line + lliitthhiisstt If set, and the ccmmddhhiisstt option is enabled, multi-line commands are saved to the history with embedded newlines rather than using semicolon separators where possible. llooggiinn__sshheellll - The shell sets this option if it is started as a login - shell (see IINNVVOOCCAATTIIOONN above). The value may not be + The shell sets this option if it is started as a login + shell (see IINNVVOOCCAATTIIOONN above). The value may not be changed. mmaaiillwwaarrnn - If set, and a file that bbaasshh is checking for mail has - been accessed since the last time it was checked, the - message ``The mail in _m_a_i_l_f_i_l_e has been read'' is dis- + If set, and a file that bbaasshh is checking for mail has + been accessed since the last time it was checked, the + message ``The mail in _m_a_i_l_f_i_l_e has been read'' is dis- played. nnoo__eemmppttyy__ccmmdd__ccoommpplleettiioonn - If set, and rreeaaddlliinnee is being used, bbaasshh will not + If set, and rreeaaddlliinnee is being used, bbaasshh will not attempt to search the PPAATTHH for possible completions when completion is attempted on an empty line. nnooccaasseegglloobb - If set, bbaasshh matches filenames in a case-insensitive + If set, bbaasshh matches filenames in a case-insensitive fashion when performing pathname expansion (see PPaatthhnnaammee EExxppaannssiioonn above). nnooccaasseemmaattcchh - If set, bbaasshh matches patterns in a case-insensitive + If set, bbaasshh matches patterns in a case-insensitive fashion when performing matching while executing ccaassee or [[[[ conditional commands. nnuullllgglloobb - If set, bbaasshh allows patterns which match no files (see - PPaatthhnnaammee EExxppaannssiioonn above) to expand to a null string, + If set, bbaasshh allows patterns which match no files (see + PPaatthhnnaammee EExxppaannssiioonn above) to expand to a null string, rather than themselves. pprrooggccoommpp If set, the programmable completion facilities (see PPrroo-- @@ -5105,48 +5340,50 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS enabled by default. pprroommppttvvaarrss If set, prompt strings undergo parameter expansion, com- - mand substitution, arithmetic expansion, and quote - removal after being expanded as described in PPRROOMMPPTTIINNGG + mand substitution, arithmetic expansion, and quote + removal after being expanded as described in PPRROOMMPPTTIINNGG above. This option is enabled by default. rreessttrriicctteedd__sshheellll - The shell sets this option if it is started in + The shell sets this option if it is started in restricted mode (see RREESSTTRRIICCTTEEDD SSHHEELLLL below). The value - may not be changed. This is not reset when the startup - files are executed, allowing the startup files to dis- + may not be changed. This is not reset when the startup + files are executed, allowing the startup files to dis- cover whether or not a shell is restricted. sshhiifftt__vveerrbboossee - If set, the sshhiifftt builtin prints an error message when + If set, the sshhiifftt builtin prints an error message when the shift count exceeds the number of positional parame- ters. ssoouurrcceeppaatthh If set, the ssoouurrccee (..) builtin uses the value of PPAATTHH 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. xxppgg__eecchhoo - If set, the eecchhoo builtin expands backslash-escape + If set, the eecchhoo builtin expands backslash-escape sequences by default. + ssuussppeenndd [--ff] - Suspend the execution of this shell until it receives a SSIIGGCCOONNTT + Suspend the execution of this shell until it receives a SSIIGGCCOONNTT signal. A login shell cannot be suspended; the --ff option can be used to override this and force the suspension. The return sta- - tus is 0 unless the shell is a login shell and --ff is not sup- + tus is 0 unless the shell is a login shell and --ff is not sup- plied, or if job control is not enabled. + tteesstt _e_x_p_r [[ _e_x_p_r ]] - Return a status of 0 or 1 depending on the evaluation of the - conditional expression _e_x_p_r. Each operator and operand must be - a separate argument. Expressions are composed of the primaries - described above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. tteesstt does not - accept any options, nor does it accept and ignore an argument of - ---- as signifying the end of options. - - Expressions may be combined using the following operators, + Return a status of 0 (true) or 1 (false) depending on the evalu- + ation of the conditional expression _e_x_p_r. Each operator and op- + erand must be a separate argument. Expressions are composed of + the primaries described above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. + tteesstt does not accept any options, nor does it accept and ignore + an argument of ---- as signifying the end of options. + + Expressions may be combined using the following operators, listed in decreasing order of precedence. The evaluation - depends on the number of arguments; see below. Operator prece- + depends on the number of arguments; see below. Operator prece- dence is used when there are five or more arguments. !! _e_x_p_r True if _e_x_p_r is false. (( _e_x_p_r )) - Returns the value of _e_x_p_r. This may be used to override + Returns the value of _e_x_p_r. This may be used to override the normal precedence of operators. _e_x_p_r_1 -aa _e_x_p_r_2 True if both _e_x_p_r_1 and _e_x_p_r_2 are true. @@ -5163,76 +5400,79 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS null. 2 arguments If the first argument is !!, 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 - above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the expression is + only if the second argument is null. If the first argu- + ment is one of the unary conditional operators listed + above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, 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 + If the second argument is one of the binary conditional operators listed above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the result of the expression is the result of the binary test - using the first and third arguments as operands. The --aa - and --oo operators are considered binary operators when - there are three arguments. If the first argument is !!, - the value is the negation of the two-argument test using + using the first and third arguments as operands. The --aa + and --oo operators are considered binary operators when + there are three arguments. If the first argument is !!, + the value is the negation of the two-argument test using the second and third arguments. If the first argument is exactly (( and the third argument is exactly )), the result - is the one-argument test of the second argument. Other- + is the one-argument test of the second argument. Other- wise, the expression is false. 4 arguments If the first argument is !!, the result is the negation of - the three-argument expression composed of the remaining + the three-argument expression composed of the remaining arguments. Otherwise, the expression is parsed and eval- - uated according to precedence using the rules listed + uated 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 tteesstt or [[, the << and >> operators sort lexico- + When used with tteesstt or [[, the << and >> operators sort lexico- graphically using ASCII ordering. - ttiimmeess Print the accumulated user and system times for the shell and + ttiimmeess Print the accumulated user and system times for the shell and for processes run from the shell. The return status is 0. ttrraapp [--llpp] [[_a_r_g] _s_i_g_s_p_e_c ...] - The command _a_r_g is to be read and executed when the shell - receives signal(s) _s_i_g_s_p_e_c. If _a_r_g is absent (and there is a - single _s_i_g_s_p_e_c) or --, each specified signal is reset to its - original disposition (the value it had upon entrance to the - shell). If _a_r_g is the null string the signal specified by each - _s_i_g_s_p_e_c is ignored by the shell and by the commands it invokes. - If _a_r_g is not present and --pp has been supplied, then the trap - commands associated with each _s_i_g_s_p_e_c are displayed. If no - arguments are supplied or if only --pp is given, ttrraapp prints the - list of commands associated with each signal. The --ll option - causes the shell to print a list of signal names and their cor- - responding numbers. Each _s_i_g_s_p_e_c is either a signal name - defined in <_s_i_g_n_a_l_._h>, or a signal number. Signal names are + The command _a_r_g is to be read and executed when the shell + receives signal(s) _s_i_g_s_p_e_c. If _a_r_g is absent (and there is a + single _s_i_g_s_p_e_c) or --, each specified signal is reset to its + original disposition (the value it had upon entrance to the + shell). If _a_r_g is the null string the signal specified by each + _s_i_g_s_p_e_c is ignored by the shell and by the commands it invokes. + If _a_r_g is not present and --pp has been supplied, then the trap + commands associated with each _s_i_g_s_p_e_c are displayed. If no + arguments are supplied or if only --pp is given, ttrraapp prints the + list of commands associated with each signal. The --ll option + causes the shell to print a list of signal names and their cor- + responding numbers. Each _s_i_g_s_p_e_c is either a signal name + defined in <_s_i_g_n_a_l_._h>, or a signal number. Signal names are case insensitive and the SSIIGG prefix is optional. - If a _s_i_g_s_p_e_c is EEXXIITT (0) the command _a_r_g is executed on exit - from the shell. If a _s_i_g_s_p_e_c is DDEEBBUUGG, the command _a_r_g is exe- - cuted before every _s_i_m_p_l_e _c_o_m_m_a_n_d, _f_o_r command, _c_a_s_e command, - _s_e_l_e_c_t command, every arithmetic _f_o_r command, and before the - first command executes in a shell function (see SSHHEELLLL GGRRAAMMMMAARR - above). Refer to the description of the eexxttddeebbuugg option to the + If a _s_i_g_s_p_e_c is EEXXIITT (0) the command _a_r_g is executed on exit + from the shell. If a _s_i_g_s_p_e_c is DDEEBBUUGG, the command _a_r_g is exe- + cuted before every _s_i_m_p_l_e _c_o_m_m_a_n_d, _f_o_r command, _c_a_s_e command, + _s_e_l_e_c_t command, every arithmetic _f_o_r command, and before the + first command executes in a shell function (see SSHHEELLLL GGRRAAMMMMAARR + above). Refer to the description of the eexxttddeebbuugg option to the sshhoopptt builtin for details of its effect on the DDEEBBUUGG trap. If a _s_i_g_s_p_e_c is RREETTUURRNN, the command _a_r_g is executed each time a shell function or a script executed with the .. or ssoouurrccee builtins fin- ishes executing. - If a _s_i_g_s_p_e_c is EERRRR, the command _a_r_g is executed whenever a sim- - ple command has a non-zero exit status, subject to the following - conditions. The EERRRR trap is not executed if the failed command - is part of the command list immediately following a wwhhiillee or - uunnttiill keyword, part of the test in an _i_f statement, part of a - command executed in a &&&& or |||| list, or if the command's return - value is being inverted via !!. These are the same conditions - obeyed by the eerrrreexxiitt option. + If a _s_i_g_s_p_e_c is EERRRR, the command _a_r_g is executed whenever a 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 EERRRR trap is not executed if the + failed command is part of the command list immediately following + a wwhhiillee or uunnttiill keyword, part of the test in an _i_f statement, + part of a command executed in a &&&& or |||| list except the command + following the final &&&& or ||||, any command in a pipeline but the + last, or if the command's return value is being inverted using + !!. These are the same conditions obeyed by the eerrrreexxiitt (--ee) + option. Signals ignored upon entry to the shell cannot be trapped or reset. Trapped signals that are not being ignored are reset to @@ -5252,14 +5492,14 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS fied as a command name, or nothing if ``type -t name'' would not return _f_i_l_e. The --PP option forces a PPAATTHH search for each _n_a_m_e, even if ``type -t name'' would not return _f_i_l_e. If a command is - hashed, --pp and --PP print the hashed value, not necessarily the - file that appears first in PPAATTHH. If the --aa option is used, ttyyppee - prints all of the places that contain an executable named _n_a_m_e. - This includes aliases and functions, if and only if the --pp - option is not also used. The table of hashed commands is not - consulted when using --aa. The --ff option suppresses shell func- - tion lookup, as with the ccoommmmaanndd builtin. ttyyppee returns true if - all of the arguments are found, false if any are not found. + hashed, --pp and --PP print the hashed value, which is not necessar- + ily the file that appears first in PPAATTHH. If the --aa option is + used, ttyyppee prints all of the places that contain an executable + named _n_a_m_e. This includes aliases and functions, if and only if + the --pp option is not also used. The table of hashed commands is + not consulted when using --aa. The --ff option suppresses shell + function lookup, as with the ccoommmmaanndd builtin. ttyyppee returns true + if all of the arguments are found, false if any are not found. uulliimmiitt [--HHSSTTaabbccddeeffiillmmnnppqqrrssttuuvvxx [_l_i_m_i_t]] Provides control over the resources available to the shell and @@ -5302,13 +5542,13 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --xx The maximum number of file locks --TT The maximum number of threads - If _l_i_m_i_t is given, it is the new value of the specified resource - (the --aa option is display only). If no option is given, then --ff - is assumed. Values are in 1024-byte increments, except for --tt, - which is in seconds, --pp, which is in units of 512-byte blocks, - and --TT, --bb, --nn, and --uu, which are unscaled values. The return - status is 0 unless an invalid option or argument is supplied, or - an error occurs while setting a new limit. + If _l_i_m_i_t is given, and the --aa option is not used, _l_i_m_i_t is the + new value of the specified resource. If no option is given, + then --ff is assumed. Values are in 1024-byte increments, except + for --tt, which is in seconds; --pp, which is in units of 512-byte + blocks; and --TT, --bb, --nn, and --uu, which are unscaled values. The + return status is 0 unless an invalid option or argument is sup- + plied, or an error occurs while setting a new limit. uummaasskk [--pp] [--SS] [_m_o_d_e] The user file-creation mask is set to _m_o_d_e. If _m_o_d_e begins with @@ -5327,33 +5567,40 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS supplied, all alias definitions are removed. The return value is true unless a supplied _n_a_m_e is not a defined alias. - uunnsseett [-ffvv] [_n_a_m_e ...] + uunnsseett [-ffvv] [-nn] [_n_a_m_e ...] For each _n_a_m_e, remove the corresponding variable or function. - If no options are supplied, or the --vv option is given, each _n_a_m_e - refers to a shell variable. Read-only variables may not be + If the --vv option is given, each _n_a_m_e refers to a shell variable, + and that variable is removed. Read-only variables may not be unset. If --ff is specified, each _n_a_m_e refers to a shell func- - tion, and the function definition is removed. Each unset vari- - able or function is removed from the environment passed to sub- - sequent commands. If any of CCOOMMPP__WWOORRDDBBRREEAAKKSS, RRAANNDDOOMM, SSEECCOONNDDSS, - LLIINNEENNOO, HHIISSTTCCMMDD, FFUUNNCCNNAAMMEE, GGRROOUUPPSS, or DDIIRRSSTTAACCKK are unset, they - lose their special properties, even if they are subsequently - reset. The exit status is true unless a _n_a_m_e is readonly. - - wwaaiitt [_n _._._.] - Wait for each specified process and return its termination sta- - tus. Each _n may be a process ID or a job specification; if a + tion, and the function definition is removed. If the --nn option + is supplied, and _n_a_m_e is a variable with the _n_a_m_e_r_e_f attribute, + _n_a_m_e will be unset rather than the variable it references. --nn + has no effect if the --ff option is supplied. If no options are + supplied, each _n_a_m_e refers to a variable; if there is no vari- + able by that name, any function with that name is unset. Each + unset variable or function is removed from the environment + passed to subsequent commands. If any of CCOOMMPP__WWOORRDDBBRREEAAKKSS, RRAANN-- + DDOOMM, SSEECCOONNDDSS, LLIINNEENNOO, HHIISSTTCCMMDD, FFUUNNCCNNAAMMEE, GGRROOUUPPSS, or DDIIRRSSTTAACCKK are + unset, they lose their special properties, even if they are sub- + sequently reset. The exit status is true unless a _n_a_m_e is read- + only. + + wwaaiitt [--nn] [_n _._._.] + Wait for each specified child process and return its termination + status. Each _n 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 _n is not given, all currently active child pro- - cesses are waited for, and the return status is zero. If _n - specifies a non-existent process or job, the return status is - 127. Otherwise, the return status is the exit status of the - last process or job waited for. + cesses are waited for, and the return status is zero. If the --nn + option is supplied, wwaaiitt waits for any job to terminate and + returns its exit status. If _n specifies a non-existent process + or job, the return status is 127. Otherwise, the return status + is the exit status of the last process or job waited for. RREESSTTRRIICCTTEEDD SSHHEELLLL If bbaasshh is started with the name rrbbaasshh, or the --rr option is supplied at - invocation, the shell becomes restricted. A restricted shell is used - to set up an environment more controlled than the standard shell. It - behaves identically to bbaasshh with the exception that the following are + invocation, the shell becomes restricted. A restricted shell is used + to set up an environment more controlled than the standard shell. It + behaves identically to bbaasshh with the exception that the following are disallowed or not performed: +o changing directories with ccdd @@ -5362,16 +5609,16 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL +o specifying command names containing // - +o specifying a file name containing a // as an argument to the .. + +o specifying a filename containing a // as an argument to the .. builtin command - +o specifying a filename containing a slash as an argument to the + +o specifying a filename containing a slash as an argument to the --pp option to the hhaasshh builtin command - +o importing function definitions from the shell environment at + +o importing function definitions from the shell environment at startup - +o parsing the value of SSHHEELLLLOOPPTTSS from the shell environment at + +o parsing the value of SSHHEELLLLOOPPTTSS from the shell environment at startup +o redirecting output using the >, >|, <>, >&, &>, and >> redirect- @@ -5380,10 +5627,10 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL +o using the eexxeecc builtin command to replace the shell with another command - +o adding or deleting builtin commands with the --ff and --dd options + +o adding or deleting builtin commands with the --ff and --dd options to the eennaabbllee builtin command - +o using the eennaabbllee builtin command to enable disabled shell + +o using the eennaabbllee builtin command to enable disabled shell builtins +o specifying the --pp option to the ccoommmmaanndd builtin command @@ -5393,15 +5640,17 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL These restrictions are enforced after any startup files are read. When a command that is found to be a shell script is executed (see CCOOMM-- - MMAANNDD EEXXEECCUUTTIIOONN above), rrbbaasshh turns off any restrictions in the shell + MMAANNDD EEXXEECCUUTTIIOONN above), rrbbaasshh turns off any restrictions in the shell spawned to execute the script. SSEEEE AALLSSOO _B_a_s_h _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l, Brian Fox and Chet Ramey _T_h_e _G_n_u _R_e_a_d_l_i_n_e _L_i_b_r_a_r_y, Brian Fox and Chet Ramey _T_h_e _G_n_u _H_i_s_t_o_r_y _L_i_b_r_a_r_y, Brian Fox and Chet Ramey - _P_o_r_t_a_b_l_e _O_p_e_r_a_t_i_n_g _S_y_s_t_e_m _I_n_t_e_r_f_a_c_e _(_P_O_S_I_X_) _P_a_r_t _2_: _S_h_e_l_l _a_n_d _U_t_i_l_i_- - _t_i_e_s, IEEE + _P_o_r_t_a_b_l_e _O_p_e_r_a_t_i_n_g _S_y_s_t_e_m _I_n_t_e_r_f_a_c_e _(_P_O_S_I_X_) _P_a_r_t _2_: _S_h_e_l_l _a_n_d _U_t_i_l_i_- + _t_i_e_s, IEEE -- + http://pubs.opengroup.org/onlinepubs/9699919799/ + http://tiswww.case.edu/~chet/bash/POSIX -- a description of posix mode _s_h(1), _k_s_h(1), _c_s_h(1) _e_m_a_c_s(1), _v_i(1) _r_e_a_d_l_i_n_e(3) @@ -5416,7 +5665,7 @@ FFIILLEESS _~_/_._b_a_s_h_r_c The individual per-interactive-shell startup file _~_/_._b_a_s_h___l_o_g_o_u_t - The individual login shell cleanup file, executed when a login + The individual login shell cleanup file, executed when a login shell exits _~_/_._i_n_p_u_t_r_c Individual _r_e_a_d_l_i_n_e initialization file @@ -5430,14 +5679,14 @@ AAUUTTHHOORRSS BBUUGG RREEPPOORRTTSS If you find a bug in bbaasshh,, you should report it. But first, you should - make sure that it really is a bug, and that it appears in the latest - version of bbaasshh. The latest version is always available from + make sure that it really is a bug, and that it appears in the latest + version of bbaasshh. The latest version is always available from _f_t_p_:_/_/_f_t_p_._g_n_u_._o_r_g_/_p_u_b_/_g_n_u_/_b_a_s_h_/. - Once you have determined that a bug actually exists, use the _b_a_s_h_b_u_g - command to submit a bug report. If you have a fix, you are encouraged - to mail that as well! Suggestions and `philosophical' bug reports may - be mailed to _b_u_g_-_b_a_s_h_@_g_n_u_._o_r_g or posted to the Usenet newsgroup + Once you have determined that a bug actually exists, use the _b_a_s_h_b_u_g + command to submit a bug report. If you have a fix, you are encouraged + to mail that as well! Suggestions and `philosophical' bug reports may + be mailed to _b_u_g_-_b_a_s_h_@_g_n_u_._o_r_g or posted to the Usenet newsgroup ggnnuu..bbaasshh..bbuugg. ALL bug reports should include: @@ -5448,11 +5697,11 @@ BBUUGG RREEPPOORRTTSS A description of the bug behaviour A short script or `recipe' which exercises the bug - _b_a_s_h_b_u_g inserts the first three items automatically into the template + _b_a_s_h_b_u_g inserts the first three items automatically into the template it provides for filing a bug report. Comments and bug reports concerning this manual page should be directed - to _c_h_e_t_@_p_o_._c_w_r_u_._e_d_u. + to _c_h_e_t_._r_a_m_e_y_@_c_a_s_e_._e_d_u. BBUUGGSS It's too big and too slow. @@ -5465,10 +5714,10 @@ BBUUGGSS Shell builtin commands and functions are not stoppable/restartable. Compound commands and command sequences of the form `a ; b ; c' are not - handled gracefully when process suspension is attempted. When a - process is stopped, the shell immediately executes the next command in - the sequence. It suffices to place the sequence of commands between - parentheses to force it into a subshell, which may be stopped as a + handled gracefully when process suspension is attempted. When a + process is stopped, the shell immediately executes the next command in + the sequence. It suffices to place the sequence of commands between + parentheses to force it into a subshell, which may be stopped as a unit. Array variables may not (yet) be exported. @@ -5477,4 +5726,4 @@ BBUUGGSS -GNU Bash-4.2 2010 December 28 BASH(1) +GNU Bash 4.3 2014 February 2 BASH(1) |