From: Chet Ramey Date: Wed, 12 Jun 2013 13:28:11 +0000 (-0400) Subject: commit bash-20130503 snapshot X-Git-Tag: bash-4.4-alpha~147 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a539713adeabfc8edd2410a114307047c52540df;p=thirdparty%2Fbash.git commit bash-20130503 snapshot --- diff --git a/CWRU/POSIX.NOTES.old b/CWRU/POSIX.NOTES.old new file mode 100644 index 000000000..1707ab10c --- /dev/null +++ b/CWRU/POSIX.NOTES.old @@ -0,0 +1,82 @@ +Starting bash with the `--posix' command-line option or executing +`set -o posix' while bash is running will cause bash to conform more +closely to the Posix.2 standard by changing the behavior to match that +specified by Posix.2 in areas where the bash default differs. + +The following list is what's changed when `posix mode' is in effect: + +1. When a command in the hash table no longer exists, bash will re-search + $PATH to find the new location. This is also available with + `shopt -s checkhash'. + +2. The >& redirection does not redirect stdout and stderr. + +3. The message printed by the job control code and builtins when a job + exits with a non-zero status is `Done(status)'. + +4. Reserved words may not be aliased. + +5. The Posix.2 PS1 and PS2 expansions of `!' -> history number and + `!!' -> `!' are enabled, and parameter expansion is performed on + the value regardless of the setting of the `promptvars' option. + +6. Interactive comments are enabled by default. (Note that bash has + them on by default anyway.) + +7. The Posix.2 startup files are executed ($ENV) rather than the normal + bash files. + +8. Tilde expansion is only performed on assignments preceding a command + name, rather than on all assignment statements on the line. + +9. The default history file is ~/.sh_history (default value of $HISTFILE). + +10. The output of `kill -l' prints all the signal names on a single line, + separated by spaces. + +11. Non-interactive shells exit if `file' in `. file' is not found. + +12. Redirection operators do not perform pathname expansion on the word + in the redirection unless the shell is interactive + +13. Function names must be valid shell identifiers. That is, they may not + contain characters other than letters, digits, and underscores, and + may not start with a digit. Declaring a function with an illegal name + causes a fatal syntax error in non-interactive shells. + +14. Posix.2 `special' builtins are found before shell functions during command + lookup. + +15. If a Posix.2 special builtin returns an error status, a non-interactive + shell exits. The fatal errors are those listed in the POSIX.2 standard, + and include things like passing incorrect options, redirection errors, + variable assignment errors for assignments preceding the command name, + and so on. + +16. The environment passed to executed commands is not sorted. Neither is + the output of `set'. This is not strictly Posix.2 behavior, but sh + does it this way. Ksh does not. It's not necessary to sort the + environment; no program should rely on it being sorted. + +17. If the `cd' builtin finds a directory to change to using $CDPATH, the + value it assigns to $PWD does not contain any symbolic links, as if + `cd -P' had been executed. + +18. A non-interactive shell exits with an error status if a variable + assignment error occurs when no command name follows the assignment + statements. A variable assignment error occurs, for example, when + trying to assign a value to a read-only variable. + +19. A non-interactive shell exits with an error status if the iteration + variable in a for statement or the selection variable in a select + statement is a read-only variable. + +20. Process substitution is not available. + +21. Assignment statements preceding POSIX.2 `special' builtins persist in + the shell environment after the builtin completes. + +There is other Posix.2 behavior that bash does not implement. Specifically: + +1. Assignment statements affect the execution environment of all builtins, + not just special ones. diff --git a/CWRU/old/set.def.save b/CWRU/old/set.def.save new file mode 100644 index 000000000..87b78d7cc --- /dev/null +++ b/CWRU/old/set.def.save @@ -0,0 +1,544 @@ +This file is set.def, from which is created set.c. +It implements the "set" and "unset" builtins in Bash. + +Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc. + +This file is part of GNU Bash, the Bourne Again SHell. + +Bash is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 1, or (at your option) any later +version. + +Bash is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License along +with Bash; see the file COPYING. If not, write to the Free Software +Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + +$PRODUCES set.c + +#include +#include "../shell.h" +#include "../flags.h" + +#include "bashgetopt.h" + +extern int interactive; +extern int noclobber, posixly_correct; +#if defined (READLINE) +extern int rl_editing_mode, no_line_editing; +#endif /* READLINE */ + +$BUILTIN set +$FUNCTION set_builtin +$SHORT_DOC set [--abefhkmnptuvxldBCHP] [-o option] [arg ...] + -a Mark variables which are modified or created for export. + -b Notify of job termination immediately. + -e Exit immediately if a command exits with a non-zero status. + -f Disable file name generation (globbing). + -h Locate and remember function commands as functions are + defined. Function commands are normally looked up when + the function is executed. + -i Force the shell to be an "interactive" one. Interactive shells + always read `~/.bashrc' on startup. + -k All keyword arguments are placed in the environment for a + command, not just those that precede the command name. + -m Job control is enabled. + -n Read commands but do not execute them. + -o option-name + Set the variable corresponding to option-name: + allexport same as -a + braceexpand same as -B +#if defined (READLINE) + emacs use an emacs-style line editing interface +#endif /* READLINE */ + errexit same as -e + histexpand same as -H + ignoreeof the shell will not exit upon reading EOF + interactive-comments + allow comments to appear in interactive commands + monitor same as -m + noclobber disallow redirection to existing files + noexec same as -n + noglob same as -f + nohash same as -d + notify save as -b + nounset same as -u + physical same as -P + posix change the behavior of bash where the default + operation differs from the 1003.2 standard to + match the standard + privileged same as -p + verbose same as -v +#if defined (READLINE) + vi use a vi-style line editing interface +#endif /* READLINE */ + xtrace same as -x + -p Turned on whenever the real and effective user ids do not match. + Disables processing of the $ENV file and importing of shell + functions. Turning this option off causes the effective uid and + gid to be set to the real uid and gid. + -t Exit after reading and executing one command. + -u Treat unset variables as an error when substituting. + -v Print shell input lines as they are read. + -x Print commands and their arguments as they are executed. + -l Save and restore the binding of the NAME in a FOR command. + -d Disable the hashing of commands that are looked up for execution. + Normally, commands are remembered in a hash table, and once + found, do not have to be looked up again. +#if defined (BRACE_EXPANSION) + -B the shell will perform brace expansion +#endif /* BRACE_EXPANSION */ +#if defined (BANG_HISTORY) + -H Enable ! style history substitution. This flag is on + by default. +#endif /* BANG_HISTORY */ + -C If set, disallow existing regular files to be overwritten + by redirection of output. + -P If set, do not follow symbolic links when executing commands + such as cd which change the current directory. + +Using + rather than - causes these flags to be turned off. The +flags can also be used upon invocation of the shell. The current +set of flags may be found in $-. The remaining n ARGs are positional +parameters and are assigned, in order, to $1, $2, .. $n. If no +ARGs are given, all shell variables are printed. +$END + +/* An a-list used to match long options for set -o to the corresponding + option letter. */ +struct { + char *name; + int letter; +} o_options[] = { + { "allexport", 'a' }, +#if defined (BRACE_EXPANSION) + { "braceexpand",'B' }, +#endif + { "errexit", 'e' }, + { "histexpand", 'H' }, + { "monitor", 'm' }, + { "noexec", 'n' }, + { "noglob", 'f' }, + { "nohash", 'd' }, +#if defined (JOB_CONTROL) + { "notify", 'b' }, +#endif /* JOB_CONTROL */ + {"nounset", 'u' }, + {"physical", 'P' }, + {"privileged", 'p' }, + {"verbose", 'v' }, + {"xtrace", 'x' }, + {(char *)NULL, 0}, +}; + +#define MINUS_O_FORMAT "%-15s\t%s\n" + +void +list_minus_o_opts () +{ + register int i; + char *on = "on", *off = "off"; + + printf (MINUS_O_FORMAT, "noclobber", (noclobber == 1) ? on : off); + + if (find_variable ("ignoreeof") || find_variable ("IGNOREEOF")) + printf (MINUS_O_FORMAT, "ignoreeof", on); + else + printf (MINUS_O_FORMAT, "ignoreeof", off); + + printf (MINUS_O_FORMAT, "interactive-comments", + interactive_comments ? on : off); + + printf (MINUS_O_FORMAT, "posix", posixly_correct ? on : off); + +#if defined (READLINE) + if (no_line_editing) + { + printf (MINUS_O_FORMAT, "emacs", off); + printf (MINUS_O_FORMAT, "vi", off); + } + else + { + /* Magic. This code `knows' how readline handles rl_editing_mode. */ + printf (MINUS_O_FORMAT, "emacs", (rl_editing_mode == 1) ? on : off); + printf (MINUS_O_FORMAT, "vi", (rl_editing_mode == 0) ? on : off); + } +#endif /* READLINE */ + + for (i = 0; o_options[i].name; i++) + { + int *on_or_off, zero = 0; + + on_or_off = find_flag (o_options[i].letter); + if (on_or_off == FLAG_UNKNOWN) + on_or_off = &zero; + printf (MINUS_O_FORMAT, o_options[i].name, (*on_or_off == 1) ? on : off); + } +} + +set_minus_o_option (on_or_off, option_name) + int on_or_off; + char *option_name; +{ + int option_char = -1; + + if (STREQ (option_name, "noclobber")) + { + if (on_or_off == FLAG_ON) + bind_variable ("noclobber", ""); + else + unbind_variable ("noclobber"); + stupidly_hack_special_variables ("noclobber"); + } + else if (STREQ (option_name, "ignoreeof")) + { + unbind_variable ("ignoreeof"); + unbind_variable ("IGNOREEOF"); + if (on_or_off == FLAG_ON) + bind_variable ("IGNOREEOF", "10"); + stupidly_hack_special_variables ("IGNOREEOF"); + } + +#if defined (READLINE) + else if ((STREQ (option_name, "emacs")) || (STREQ (option_name, "vi"))) + { + if (on_or_off == FLAG_ON) + { + rl_variable_bind ("editing-mode", option_name); + + if (interactive) + with_input_from_stdin (); + no_line_editing = 0; + } + else + { + int isemacs = (rl_editing_mode == 1); + if ((isemacs && STREQ (option_name, "emacs")) || + (!isemacs && STREQ (option_name, "vi"))) + { + if (interactive) + with_input_from_stream (stdin, "stdin"); + no_line_editing = 1; + } + else + builtin_error ("not in %s editing mode", option_name); + } + } +#endif /* READLINE */ + else if (STREQ (option_name, "interactive-comments")) + interactive_comments = (on_or_off == FLAG_ON); + else if (STREQ (option_name, "posix")) + { + posixly_correct = (on_or_off == FLAG_ON); + unbind_variable ("POSIXLY_CORRECT"); + unbind_variable ("POSIX_PEDANTIC"); + if (on_or_off == FLAG_ON) + { + bind_variable ("POSIXLY_CORRECT", ""); + stupidly_hack_special_variables ("POSIXLY_CORRECT"); + } + } + else + { + register int i; + for (i = 0; o_options[i].name; i++) + { + if (STREQ (option_name, o_options[i].name)) + { + option_char = o_options[i].letter; + break; + } + } + if (option_char == -1) + { + builtin_error ("%s: unknown option name", option_name); + return (EXECUTION_FAILURE); + } + if (change_flag (option_char, on_or_off) == FLAG_ERROR) + { + bad_option (option_name); + return (EXECUTION_FAILURE); + } + } + return (EXECUTION_SUCCESS); +} + +/* Set some flags from the word values in the input list. If LIST is empty, + then print out the values of the variables instead. If LIST contains + non-flags, then set $1 - $9 to the successive words of LIST. */ +set_builtin (list) + WORD_LIST *list; +{ + int on_or_off, flag_name, force_assignment = 0; + + if (!list) + { + SHELL_VAR **vars; + + vars = all_shell_variables (); + if (vars) + { + print_var_list (vars); + free (vars); + } + + vars = all_shell_functions (); + if (vars) + { + print_var_list (vars); + free (vars); + } + + return (EXECUTION_SUCCESS); + } + + /* Check validity of flag arguments. */ + if (*list->word->word == '-' || *list->word->word == '+') + { + register char *arg; + WORD_LIST *save_list = list; + + while (list && (arg = list->word->word)) + { + char c; + + if (arg[0] != '-' && arg[0] != '+') + break; + + /* `-' or `--' signifies end of flag arguments. */ + if (arg[0] == '-' && + (!arg[1] || (arg[1] == '-' && !arg[2]))) + break; + + while (c = *++arg) + { + if (find_flag (c) == FLAG_UNKNOWN && c != 'o') + { + char s[2]; + s[0] = c; s[1] = '\0'; + bad_option (s); + if (c == '?') + builtin_usage (); + return (c == '?' ? EXECUTION_SUCCESS : EXECUTION_FAILURE); + } + } + list = list->next; + } + list = save_list; + } + + /* Do the set command. While the list consists of words starting with + '-' or '+' treat them as flags, otherwise, start assigning them to + $1 ... $n. */ + while (list) + { + char *string = list->word->word; + + /* If the argument is `--' or `-' then signal the end of the list + and remember the remaining arguments. */ + if (string[0] == '-' && (!string[1] || (string[1] == '-' && !string[2]))) + { + list = list->next; + + /* `set --' unsets the positional parameters. */ + if (string[1] == '-') + force_assignment = 1; + + /* Until told differently, the old shell behaviour of + `set - [arg ...]' being equivalent to `set +xv [arg ...]' + stands. Posix.2 says the behaviour is marked as obsolescent. */ + else + { + change_flag ('x', '+'); + change_flag ('v', '+'); + } + + break; + } + + if ((on_or_off = *string) && + (on_or_off == '-' || on_or_off == '+')) + { + int i = 1; + while (flag_name = string[i++]) + { + if (flag_name == '?') + { + builtin_usage (); + return (EXECUTION_SUCCESS); + } + else if (flag_name == 'o') /* -+o option-name */ + { + char *option_name; + WORD_LIST *opt; + + opt = list->next; + + if (!opt) + { + list_minus_o_opts (); + continue; + } + + option_name = opt->word->word; + + if (!option_name || !*option_name || (*option_name == '-')) + { + list_minus_o_opts (); + continue; + } + list = list->next; /* Skip over option name. */ + + if (set_minus_o_option (on_or_off, option_name) != EXECUTION_SUCCESS) + return (EXECUTION_FAILURE); + } + else + { + if (change_flag (flag_name, on_or_off) == FLAG_ERROR) + { + char opt[3]; + opt[0] = on_or_off; + opt[1] = flag_name; + opt[2] = '\0'; + bad_option (opt); + builtin_usage (); + return (EXECUTION_FAILURE); + } + } + } + } + else + { + break; + } + list = list->next; + } + + /* Assigning $1 ... $n */ + if (list || force_assignment) + remember_args (list, 1); + return (EXECUTION_SUCCESS); +} + +$BUILTIN unset +$FUNCTION unset_builtin +$SHORT_DOC unset [-f] [-v] [name ...] +For each NAME, remove the corresponding variable or function. Given +the `-v', unset will only act on variables. Given the `-f' flag, +unset will only act on functions. With neither flag, unset first +tries to unset a variable, and if that fails, then tries to unset a +function. Some variables (such as PATH and IFS) cannot be unset; also +see readonly. +$END + +#define NEXT_VARIABLE() any_failed++; list = list->next; continue; + +unset_builtin (list) + WORD_LIST *list; +{ + int unset_function, unset_variable, unset_array, opt, any_failed; + char *name; + + unset_function = unset_variable = unset_array = any_failed = 0; + + reset_internal_getopt (); + while ((opt = internal_getopt (list, "fv")) != -1) + { + switch (opt) + { + case 'f': + unset_function = 1; + break; + case 'v': + unset_variable = 1; + break; + default: + builtin_usage (); + return (EXECUTION_FAILURE); + } + } + + list = loptend; + + if (unset_function && unset_variable) + { + builtin_error ("cannot simultaneously unset a function and a variable"); + return (EXECUTION_FAILURE); + } + + while (list) + { + SHELL_VAR *var; + int tem; +#if defined (ARRAY_VARS) + char *t; +#endif + + name = list->word->word; + +#if defined (ARRAY_VARS) + if (!unset_function && valid_array_reference (name)) + { + t = strchr (name, '['); + *t++ = '\0'; + unset_array++; + } +#endif + + var = unset_function ? find_function (name) : find_variable (name); + + if (var && !unset_function && non_unsettable_p (var)) + { + builtin_error ("%s: cannot unset", name); + NEXT_VARIABLE (); + } + + /* Posix.2 says that unsetting readonly variables is an error. */ + if (var && readonly_p (var)) + { + builtin_error ("%s: cannot unset: readonly %s", + name, unset_function ? "function" : "variable"); + NEXT_VARIABLE (); + } + + /* Unless the -f option is supplied, the name refers to a variable. */ +#if defined (ARRAY_VARS) + if (var && unset_array) + { + if (array_p (var) == 0) + { + builtin_error ("%s: not an array variable", name); + NEXT_VARIABLE (); + } + else + tem = unbind_array_element (var, t); + } + else +#endif /* ARRAY_VARS */ + tem = makunbound (name, unset_function ? shell_functions : shell_variables); + + /* This is what Posix.2 draft 11+ says. ``If neither -f nor -v + is specified, the name refers to a variable; if a variable by + that name does not exist, a function by that name, if any, + shall be unset.'' */ + if ((tem == -1) && !unset_function && !unset_variable) + tem = makunbound (name, shell_functions); + + if (tem == -1) + any_failed++; + else if (!unset_function) + stupidly_hack_special_variables (name); + + list = list->next; + } + + if (any_failed) + return (EXECUTION_FAILURE); + else + return (EXECUTION_SUCCESS); +} diff --git a/CWRU/save/unwind_prot.h.save b/CWRU/save/unwind_prot.h.save new file mode 100644 index 000000000..998fd72b6 --- /dev/null +++ b/CWRU/save/unwind_prot.h.save @@ -0,0 +1,50 @@ +/* unwind_prot.h - Macros and functions for hacking unwind protection. */ + +/* Copyright (C) 1993 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License as published by the Free + Software Foundation; either version 2, or (at your option) any later + version. + + Bash is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License along + with Bash; see the file COPYING. If not, write to the Free Software + Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#if !defined (_UNWIND_PROT_H) +#define _UNWIND_PROT_H + +/* Run a function without interrupts. */ +extern void begin_unwind_frame (); +extern void discard_unwind_frame (); +extern void run_unwind_frame (); +extern void add_unwind_protect (); +extern void remove_unwind_protect (); +extern void run_unwind_protects (); +extern void unwind_protect_var (); + +/* Define for people who like their code to look a certain way. */ +#define end_unwind_frame() + +/* How to protect an integer. */ +#define unwind_protect_int(X) unwind_protect_var (&(X), (char *)(X), sizeof (int)) + +/* How to protect a pointer to a string. */ +#define unwind_protect_string(X) \ + unwind_protect_var ((int *)&(X), (X), sizeof (char *)) + +/* How to protect any old pointer. */ +#define unwind_protect_pointer(X) unwind_protect_string (X) + +/* How to protect the contents of a jmp_buf. */ +#define unwind_protect_jmp_buf(X) \ + unwind_protect_var ((int *)(X), (char *)(X), sizeof (procenv_t)) + +#endif /* _UNWIND_PROT_H */ diff --git a/cross-build/cygwin32.cache.old b/cross-build/cygwin32.cache.old new file mode 100644 index 000000000..640390fbf --- /dev/null +++ b/cross-build/cygwin32.cache.old @@ -0,0 +1,42 @@ +# This file is a shell script that caches the results of configure +# tests for CYGWIN32 so they don't need to be done when cross-compiling. + +# AC_FUNC_GETPGRP should also define GETPGRP_VOID +ac_cv_func_getpgrp_void=${ac_cv_func_getpgrp_void='yes'} +# AC_FUNC_SETVBUF_REVERSED should not define anything else +ac_cv_func_setvbuf_reversed=${ac_cv_func_setvbuf_reversed='no'} +# on CYGWIN32, system calls do not restart +ac_cv_sys_restartable_syscalls=${ac_cv_sys_restartable_syscalls='no'} +bash_cv_sys_restartable_syscalls=${bash_cv_sys_restartable_syscalls='no'} + +# these may be necessary, but they are currently commented out +#ac_cv_c_bigendian=${ac_cv_c_bigendian='no'} +ac_cv_sizeof_char_p=${ac_cv_sizeof_char_p='4'} +ac_cv_sizeof_int=${ac_cv_sizeof_int='4'} +ac_cv_sizeof_long=${ac_cv_sizeof_long='4'} +ac_cv_sizeof_double=${ac_cv_sizeof_double='8'} + +bash_cv_dup2_broken=${bash_cv_dup2_broken='no'} +bash_cv_pgrp_pipe=${bash_cv_pgrp_pipe='no'} +bash_cv_type_rlimit=${bash_cv_type_rlimit='long'} +bash_cv_decl_under_sys_siglist=${bash_cv_decl_under_sys_siglist='no'} +bash_cv_under_sys_siglist=${bash_cv_under_sys_siglist='no'} +bash_cv_sys_siglist=${bash_cv_sys_siglist='no'} +bash_cv_opendir_not_robust=${bash_cv_opendir_not_robust='no'} +bash_cv_getenv_redef=${bash_cv_getenv_redef='yes'} +bash_cv_printf_declared=${bash_cv_printf_declared='yes'} +bash_cv_ulimit_maxfds=${bash_cv_ulimit_maxfds='no'} +bash_cv_getcwd_calls_popen=${bash_cv_getcwd_calls_popen='no'} +bash_cv_must_reinstall_sighandlers=${bash_cv_must_reinstall_sighandlers='no'} +bash_cv_job_control_missing=${bash_cv_job_control_missing='present'} +bash_cv_sys_named_pipes=${bash_cv_sys_named_pipes='missing'} +bash_cv_func_sigsetjmp=${bash_cv_func_sigsetjmp='missing'} +bash_cv_mail_dir=${bash_cv_mail_dir='unknown'} +bash_cv_func_strcoll_broken=${bash_cv_func_strcoll_broken='no'} + +bash_cv_type_int32_t=${bash_cv_type_int32_t='int'} +bash_cv_type_u_int32_t=${bash_cv_type_u_int32_t='int'} + +ac_cv_type_bits64_t=${ac_cv_type_bits64_t='no'} + +# end of cross-build/cygwin32.cache diff --git a/doc/FAQ.orig b/doc/FAQ.orig new file mode 100644 index 000000000..1cff3c8ef --- /dev/null +++ b/doc/FAQ.orig @@ -0,0 +1,1745 @@ +This is the Bash FAQ, version 3.24, for Bash version 2.05b. + +This document contains a set of frequently-asked questions concerning +Bash, the GNU Bourne-Again Shell. Bash is a freely-available command +interpreter with advanced features for both interactive use and shell +programming. + +Another good source of basic information about shells is the collection +of FAQ articles periodically posted to comp.unix.shell. + +Questions and comments concerning this document should be sent to +chet@po.cwru.edu. + +This document is available for anonymous FTP with the URL + +ftp://ftp.cwru.edu/pub/bash/FAQ + +The Bash home page is http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html + +---------- +Contents: + +Section A: The Basics + +A1) What is it? +A2) What's the latest version? +A3) Where can I get it? +A4) On what machines will bash run? +A5) Will bash run on operating systems other than Unix? +A6) How can I build bash with gcc? +A7) How can I make bash my login shell? +A8) I just changed my login shell to bash, and now I can't FTP into my + machine. Why not? +A9) What's the `POSIX 1003.2 standard'? +A10) What is the bash `posix mode'? + +Section B: The latest version + +B1) What's new in version 2.05b? +B2) Are there any user-visible incompatibilities between bash-2.05b and + bash-1.14.7? + +Section C: Differences from other Unix shells + +C1) How does bash differ from sh, the Bourne shell? +C2) How does bash differ from the Korn shell, version ksh88? +C3) Which new features in ksh-93 are not in bash, and which are? + +Section D: Why does bash do some things differently than other Unix shells? + +D1) Why does bash run a different version of `command' than + `which command' says it will? +D2) Why doesn't bash treat brace expansions exactly like csh? +D3) Why doesn't bash have csh variable modifiers? +D4) How can I make my csh aliases work when I convert to bash? +D5) How can I pipe standard output and standard error from one command to + another, like csh does with `|&'? +D6) Now that I've converted from ksh to bash, are there equivalents to + ksh features like autoloaded functions and the `whence' command? + +Section E: Why does bash do certain things the way it does? + +E1) Why is the bash builtin `test' slightly different from /bin/test? +E2) Why does bash sometimes say `Broken pipe'? +E3) When I have terminal escape sequences in my prompt, why does bash + wrap lines at the wrong column? +E4) If I pipe the output of a command into `read variable', why doesn't + the output show up in $variable when the read command finishes? +E5) I have a bunch of shell scripts that use backslash-escaped characters + in arguments to `echo'. Bash doesn't interpret these characters. Why + not, and how can I make it understand them? +E6) Why doesn't a while or for loop get suspended when I type ^Z? +E7) What about empty for loops in Makefiles? +E8) Why does the arithmetic evaluation code complain about `08'? +E9) Why does the pattern matching expression [A-Z]* match files beginning + with every letter except `z'? +E10) Why does `cd //' leave $PWD as `//'? +E11) If I resize my xterm while another program is running, why doesn't bash + notice the change? + +Section F: Things to watch out for on certain Unix versions + +F1) Why can't I use command line editing in my `cmdtool'? +F2) I built bash on Solaris 2. Why do globbing expansions and filename + completion chop off the first few characters of each filename? +F3) Why does bash dump core after I interrupt username completion or + `~user' tilde expansion on a machine running NIS? +F4) I'm running SVR4.2. Why is the line erased every time I type `@'? +F5) Why does bash report syntax errors when my C News scripts use a + redirection before a subshell command? +F6) Why can't I use vi-mode editing on Red Hat Linux 6.1? +F7) Why do bash-2.05a and bash-2.05b fail to compile `printf.def' on + HP/UX 11.x? + +Section G: How can I get bash to do certain common things? + +G1) How can I get bash to read and display eight-bit characters? +G2) How do I write a function `x' to replace builtin command `x', but + still invoke the command from within the function? +G3) How can I find the value of a shell variable whose name is the value + of another shell variable? +G4) How can I make the bash `time' reserved word print timing output that + looks like the output from my system's /usr/bin/time? +G5) How do I get the current directory into my prompt? +G6) How can I rename "*.foo" to "*.bar"? +G7) How can I translate a filename from uppercase to lowercase? +G8) How can I write a filename expansion (globbing) pattern that will match + all files in the current directory except "." and ".."? + +Section H: Where do I go from here? + +H1) How do I report bugs in bash, and where should I look for fixes and + advice? +H2) What kind of bash documentation is there? +H3) What's coming in future versions? +H4) What's on the bash `wish list'? +H5) When will the next release appear? + +---------- +Section A: The Basics + +A1) What is it? + +Bash is a Unix command interpreter (shell). It is an implementation of +the Posix 1003.2 shell standard, and resembles the Korn and System V +shells. + +Bash contains a number of enhancements over those shells, both +for interactive use and shell programming. Features geared +toward interactive use include command line editing, command +history, job control, aliases, and prompt expansion. Programming +features include additional variable expansions, shell +arithmetic, and a number of variables and options to control +shell behavior. + +Bash was originally written by Brian Fox of the Free Software +Foundation. The current developer and maintainer is Chet Ramey +of Case Western Reserve University. + +A2) What's the latest version? + +The latest version is 2.05b, first made available on Wednesday, 17 +July, 2002. + +A3) Where can I get it? + +Bash is the GNU project's shell, and so is available from the +master GNU archive site, ftp.gnu.org, and its mirrors. The +latest version is also available for FTP from ftp.cwru.edu. +The following URLs tell how to get version 2.05b: + +ftp://ftp.gnu.org/pub/gnu/bash/bash-2.05b.tar.gz +ftp://ftp.cwru.edu/pub/bash/bash-2.05b.tar.gz + +Formatted versions of the documentation are available with the URLs: + +ftp://ftp.gnu.org/pub/gnu/bash/bash-doc-2.05b.tar.gz +ftp://ftp.cwru.edu/pub/bash/bash-doc-2.05b.tar.gz + +A4) On what machines will bash run? + +Bash has been ported to nearly every version of UNIX. All you +should have to do to build it on a machine for which a port +exists is to type `configure' and then `make'. The build process +will attempt to discover the version of UNIX you have and tailor +itself accordingly, using a script created by GNU autoconf. + +More information appears in the file `INSTALL' in the distribution. + +The Bash web page (http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html) +explains how to obtain binary versions of bash for most of the major +commercial Unix systems. + +A5) Will bash run on operating systems other than Unix? + +Configuration specifics for Unix-like systems such as QNX and +LynxOS are included in the distribution. Bash-2.05 and later +versions should compile and run on Minix 2.0 (patches were +contributed), but I don't believe anyone has built bash-2.x on +earlier Minix versions yet. + +Bash has been ported to versions of Windows implementing the Win32 +programming interface. This includes Windows 95 and Windows NT. +The port was done by Cygnus Solutions as part of their CYGWIN +project. For more information about the project, look at the URLs + +http://www.cygwin.com/ +http://sourceware.cygnus.com/cygwin + +Cygnus originally ported bash-1.14.7, and that port was part of their +early GNU-Win32 (the original name) releases. Cygnus has also done a +port of bash-2.05 to the CYGWIN environment, and it is available as +part of their current release. + +Bash-2.05b should require no local Cygnus changes to build and run under +CYGWIN. + +The Cygnus port works only on Intel machines. There is a port of bash +(I don't know which version) to the alpha/NT environment available from + +ftp://ftp.gnustep.org//pub/win32/bash-alpha-nt-1.01.tar.gz + +DJ Delorie has a port of bash-2.x which runs under MS-DOS, as part +of the DJGPP project. For more information on the project, see + +http://www.delorie.com/djgpp/ + +I have been told that the original DJGPP port was done by Daisuke Aoyama. + +Mark Elbrecht has sent me notice that bash-2.04 +is available for DJGPP V2. The files are available as: + +ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2gnu/bsh204b.zip binary +ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2gnu/bsh204d.zip documentation +ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2gnu/bsh204s.zip source + +Mark has begun to work with bash-2.05, but I don't know the status. + +Ports of bash-1.12 and bash-2.0 are available for OS/2 from + +ftp://hobbes.nmsu.edu/pub/os2/util/shell/bash_112.zip +ftp://hobbes.nmsu.edu/pub/os2/util/shell/bash-2.0(253).zip + +I haven't looked at either, but the second appears to be a binary-only +distribution. Beware. + +I have received word that Bash (I'm not sure which version, but I +believe that it's at least bash-2.02.1) is the standard shell on +BeOS. + +A6) How can I build bash with gcc? + +Bash configures to use gcc by default if it is available. Read the +file INSTALL in the distribution for more information. + +A7) How can I make bash my login shell? + +Some machines let you use `chsh' to change your login shell. Other +systems use `passwd -s' or `passwd -e'. If one of these works for +you, that's all you need. Note that many systems require the full +pathname to a shell to appear in /etc/shells before you can make it +your login shell. For this, you may need the assistance of your +friendly local system administrator. + +If you cannot do this, you can still use bash as your login shell, but +you need to perform some tricks. The basic idea is to add a command +to your login shell's startup file to replace your login shell with +bash. + +For example, if your login shell is csh or tcsh, and you have installed +bash in /usr/gnu/bin/bash, add the following line to ~/.login: + + if ( -f /usr/gnu/bin/bash ) exec /usr/gnu/bin/bash --login + +(the `--login' tells bash that it is a login shell). + +It's not a good idea to put this command into ~/.cshrc, because every +csh you run without the `-f' option, even ones started to run csh scripts, +reads that file. If you must put the command in ~/.cshrc, use something +like + + if ( $?prompt ) exec /usr/gnu/bin/bash --login + +to ensure that bash is exec'd only when the csh is interactive. + +If your login shell is sh or ksh, you have to do two things. + +First, create an empty file in your home directory named `.bash_profile'. +The existence of this file will prevent the exec'd bash from trying to +read ~/.profile, and re-execing itself over and over again. ~/.bash_profile +is the first file bash tries to read initialization commands from when +it is invoked as a login shell. + +Next, add a line similar to the above to ~/.profile: + + [ -f /usr/gnu/bin/bash ] && [ -x /usr/gnu/bin/bash ] && \ + exec /usr/gnu/bin/bash --login + +This will cause login shells to replace themselves with bash running as +a login shell. Once you have this working, you can copy your initialization +code from ~/.profile to ~/.bash_profile. + +I have received word that the recipe supplied above is insufficient for +machines running CDE. CDE has a maze of twisty little startup files, all +slightly different. + +If you cannot change your login shell in the password file to bash, you +will have to (apparently) live with CDE using the shell in the password +file to run its startup scripts. If you have changed your shell to bash, +there is code in the CDE startup files (on Solaris, at least) that attempts +to do the right thing. It is, however, often broken, and may require that +you use the $BASH_ENV trick described below. + +`dtterm' claims to use $SHELL as the default program to start, so if you +can change $SHELL in the CDE startup files, you should be able to use bash +in your terminal windows. + +Setting DTSOURCEPROFILE in ~/.dtprofile will cause the `Xsession' program +to read your login shell's startup files. You may be able to use bash for +the rest of the CDE programs by setting SHELL to bash in ~/.dtprofile as +well, but I have not tried this. + +You can use the above `exec' recipe to start bash when not logging in with +CDE by testing the value of the DT variable: + + if [ -n "$DT" ]; then + [ -f /usr/gnu/bin/bash ] && exec /usr/gnu/bin/bash --login + fi + +If CDE starts its shells non-interactively during login, the login shell +startup files (~/.profile, ~/.bash_profile) will not be sourced at login. +To get around this problem, append a line similar to the following to your +~/.dtprofile: + + BASH_ENV=${HOME}/.bash_profile ; export BASH_ENV + +and add the following line to the beginning of ~/.bash_profile: + + unset BASH_ENV + +A8) I just changed my login shell to bash, and now I can't FTP into my + machine. Why not? + +You must add the full pathname to bash to the file /etc/shells. As +noted in the answer to the previous question, many systems require +this before you can make bash your login shell. + +Most versions of ftpd use this file to prohibit `special' users +such as `uucp' and `news' from using FTP. + +A9) What's the `POSIX 1003.2 standard'? + +POSIX is a name originally coined by Richard Stallman for a +family of open system standards based on UNIX. There are a +number of aspects of UNIX under consideration for +standardization, from the basic system services at the system +call and C library level to applications and tools to system +administration and management. Each area of standardization is +assigned to a working group in the 1003 series. + +The POSIX Shell and Utilities standard has been developed by IEEE +Working Group 1003.2 (POSIX.2). It concentrates on the command +interpreter interface and utility programs commonly executed from +the command line or by other programs. An initial version of the +standard has been approved and published by the IEEE, and work is +currently underway to update it. + +Bash is concerned with the aspects of the shell's behavior +defined by POSIX.2. The shell command language has of course +been standardized, including the basic flow control and program +execution constructs, I/O redirection and pipelining, argument +handling, variable expansion, and quoting. + +The `special' builtins, which must be implemented as part of the +shell to provide the desired functionality, are specified as +being part of the shell; examples of these are `eval' and +`export'. Other utilities appear in the sections of POSIX.2 not +devoted to the shell which are commonly (and in some cases must +be) implemented as builtin commands, such as `read' and `test'. +POSIX.2 also specifies aspects of the shell's interactive +behavior as part of the UPE, including job control and command +line editing. Only vi-style line editing commands have been +standardized; emacs editing commands were left out due to +objections. + +The Open Group has made an older version of its Single Unix +Specification (version 2), which is very similar to POSIX.2, +available on the web at + +http://www.opengroup.org/onlinepubs/007908799/ + +The Single Unix Specification, version 3, is available on the web at + +http://www.opengroup.org/onlinepubs/007904975/ + +A10) What is the bash `posix mode'? + +Although bash is an implementation of the POSIX.2 shell +specification, there are areas where the bash default behavior +differs from that spec. The bash `posix mode' changes the bash +behavior in these areas so that it obeys the spec more closely. + +Posix mode is entered by starting bash with the --posix or +'-o posix' option or executing `set -o posix' after bash is running. + +The specific aspects of bash which change when posix mode is +active are listed in the file POSIX in the bash distribution. +They are also listed in a section in the Bash Reference Manual +(from which that file is generated). + +Section B: The latest version + +B1) What's new in version 2.05b? + +The raison d'etre for bash-2.05b is to make a second intermediate +release containing the first of the new features to be available +in bash-3.0 and get feedback on those features before proceeding. +The major new feature is multibyte character support in both Bash +and Readline. + +Bash-2.05b contains the following new features (see the manual page for +complete descriptions and the CHANGES and NEWS files in the bash-2.05b +distribution): + +o support for multibyte characters has been added to both bash and readline + +o the DEBUG trap is now run *before* simple commands, ((...)) commands, + [[...]] conditional commands, and for ((...)) loops + +o the shell now performs arithmetic in the largest integer size the machine + supports (intmax_t) + +o there is a new \D{...} prompt expansion; passes the `...' to strftime(3) + and inserts the result into the expanded prompt + +o there is a new `here-string' redirection operator: <<< word + +o when displaying variables, function attributes and definitions are shown + separately, allowing them to be re-used as input (attempting to re-use + the old output would result in syntax errors). + +o `read' has a new `-u fd' option to read from a specified file descriptor + +o the bash debugger in examples/bashdb has been modified to work with the + new DEBUG trap semantics, the command set has been made more gdb-like, + and the changes to $LINENO make debugging functions work better + +o the expansion of $LINENO inside a shell function is only relative to the + function start if the shell is interactive -- if the shell is running a + script, $LINENO expands to the line number in the script. This is as + POSIX-2001 requires + + +A short feature history dating from Bash-2.0: + +Bash-2.05a introduced the following new features: + +o The `printf' builtin has undergone major work + +o There is a new read-only `shopt' option: login_shell, which is set by + login shells and unset otherwise + +o New `\A' prompt string escape sequence; expanding to time in 24-hour + HH:MM format + +o New `-A group/-g' option to complete and compgen; goes group name + completion + +o New [+-]O invocation option to set and unset `shopt' options at startup + +o ksh-like `ERR' trap + +o `for' loops now allow empty word lists after the `in' reserved word + +o new `hard' and `soft' arguments for the `ulimit' builtin + +o Readline can be configured to place the user at the same point on the line + when retrieving commands from the history list + +o Readline can be configured to skip `hidden' files (filenames with a leading + `.' on Unix) when performing completion + +Bash-2.05 introduced the following new features: + +o This version has once again reverted to using locales and strcoll(3) when + processing pattern matching bracket expressions, as POSIX requires. +o Added a new `--init-file' invocation argument as a synonym for `--rcfile', + per the new GNU coding standards. +o The /dev/tcp and /dev/udp redirections now accept service names as well as + port numbers. +o `complete' and `compgen' now take a `-o value' option, which controls some + of the aspects of that compspec. Valid values are: + + default - perform bash default completion if programmable + completion produces no matches + dirnames - perform directory name completion if programmable + completion produces no matches + filenames - tell readline that the compspec produces filenames, + so it can do things like append slashes to + directory names and suppress trailing spaces +o A new loadable builtin, realpath, which canonicalizes and expands symlinks + in pathname arguments. +o When `set' is called without options, it prints function defintions in a + way that allows them to be reused as input. This affects `declare' and + `declare -p' as well. This only happens when the shell is not in POSIX + mode, since POSIX.2 forbids this behavior. + +Bash-2.04 introduced the following new features: + +o Programmable word completion with the new `complete' and `compgen' builtins; + examples are provided in examples/complete/complete-examples +o `history' has a new `-d' option to delete a history entry +o `bind' has a new `-x' option to bind key sequences to shell commands +o The prompt expansion code has new `\j' and `\l' escape sequences +o The `no_empty_cmd_completion' shell option, if enabled, inhibits + command completion when TAB is typed on an empty line +o `help' has a new `-s' option to print a usage synopsis +o New arithmetic operators: var++, var--, ++var, --var, expr1,expr2 (comma) +o New ksh93-style arithmetic for command: + for ((expr1 ; expr2; expr3 )); do list; done +o `read' has new options: `-t', `-n', `-d', `-s' +o The redirection code handles several filenames specially: /dev/fd/N, + /dev/stdin, /dev/stdout, /dev/stderr +o The redirection code now recognizes /dev/tcp/HOST/PORT and + /dev/udp/HOST/PORT and tries to open a TCP or UDP socket, respectively, + to the specified port on the specified host +o The ${!prefix*} expansion has been implemented +o A new FUNCNAME variable, which expands to the name of a currently-executing + function +o The GROUPS variable is no longer readonly +o A new shopt `xpg_echo' variable, to control the behavior of echo with + respect to backslash-escape sequences at runtime +o The NON_INTERACTIVE_LOGIN_SHELLS #define has returned + +The version of Readline released with Bash-2.04, Readline-4.1, had several +new features as well: + +o Parentheses matching is always compiled into readline, and controllable + with the new `blink-matching-paren' variable +o The history-search-forward and history-search-backward functions now leave + point at the end of the line when the search string is empty, like + reverse-search-history, and forward-search-history +o A new function for applications: rl_on_new_line_with_prompt() +o New variables for applications: rl_already_prompted, and rl_gnu_readline_p + + +Bash-2.03 had very few new features, in keeping with the convention +that odd-numbered releases provide mainly bug fixes. A number of new +features were added to Readline, mostly at the request of the Cygnus +folks. + +A new shopt option, `restricted_shell', so that startup files can test + whether or not the shell was started in restricted mode +Filename generation is now performed on the words between ( and ) in + compound array assignments (this is really a bug fix) +OLDPWD is now auto-exported, as POSIX.2 requires +ENV and BASH_ENV are read-only variables in a restricted shell +Bash may now be linked against an already-installed Readline library, + as long as the Readline library is version 4 or newer +All shells begun with the `--login' option will source the login shell + startup files, even if the shell is not interactive + +There were lots of changes to the version of the Readline library released +along with Bash-2.03. For a complete list of the changes, read the file +CHANGES in the Bash-2.03 distribution. + +Bash-2.02 contained the following new features: + +a new version of malloc (based on the old GNU malloc code in previous + bash versions) that is more page-oriented, more conservative + with memory usage, does not `orphan' large blocks when they + are freed, is usable on 64-bit machines, and has allocation + checking turned on unconditionally +POSIX.2-style globbing character classes ([:alpha:], [:alnum:], etc.) +POSIX.2-style globbing equivalence classes +POSIX.2-style globbing collating symbols +the ksh [[...]] extended conditional command +the ksh egrep-style extended pattern matching operators +a new `printf' builtin +the ksh-like $(, &>, >|, <<<, [n]<&word-, [n]>&word- + prompt string special char translation and variable expansion + auto-export of variables in initial environment + command search finds functions before builtins + bash return builtin will exit a file sourced with `.' + builtins: cd -/-L/-P, exec -l/-c/-a, echo -e/-E, hash -d/-l/-p/-t. + export -n/-f/-p/name=value, pwd -L/-P, + read -e/-p/-a/-t/-n/-d/-s/-u, + readonly -a/-f/name=value, trap -l, set +o, + set -b/-m/-o option/-h/-p/-B/-C/-H/-P, + unset -f/-v, ulimit -m/-p/-u, + type -a/-p/-t/-f/-P, suspend -f, kill -n, + test -o optname/s1 == s2/s1 < s2/s1 > s2/-nt/-ot/-ef/-O/-G/-S + bash reads ~/.bashrc for interactive shells, $ENV for non-interactive + bash restricted shell mode is more extensive + bash allows functions and variables with the same name + brace expansion + tilde expansion + arithmetic expansion with $((...)) and `let' builtin + the `[[...]]' extended conditional command + process substitution + aliases and alias/unalias builtins + local variables in functions and `local' builtin + readline and command-line editing with programmable completion + command history and history/fc builtins + csh-like history expansion + other new bash builtins: bind, command, compgen, complete, builtin, + declare/typeset, dirs, enable, fc, help, + history, logout, popd, pushd, disown, shopt, + printf + exported functions + filename generation when using output redirection (command >a*) + POSIX.2-style globbing character classes + POSIX.2-style globbing equivalence classes + POSIX.2-style globbing collating symbols + egrep-like extended pattern matching operators + case-insensitive pattern matching and globbing + variable assignments preceding commands affect only that command, + even for builtins and functions + posix mode + redirection to /dev/fd/N, /dev/stdin, /dev/stdout, /dev/stderr, + /dev/tcp/host/port, /dev/udp/host/port + +Things sh has that bash does not: + uses variable SHACCT to do shell accounting + includes `stop' builtin (bash can use alias stop='kill -s STOP') + `newgrp' builtin + turns on job control if called as `jsh' + $TIMEOUT (like bash $TMOUT) + `^' is a synonym for `|' + new SVR4.2 sh builtins: mldmode, priv + +Implementation differences: + redirection to/from compound commands causes sh to create a subshell + bash does not allow unbalanced quotes; sh silently inserts them at EOF + bash does not mess with signal 11 + sh sets (euid, egid) to (uid, gid) if -p not supplied and uid < 100 + bash splits only the results of expansions on IFS, using POSIX.2 + field splitting rules; sh splits all words on IFS + sh does not allow MAILCHECK to be unset (?) + sh does not allow traps on SIGALRM or SIGCHLD + bash allows multiple option arguments when invoked (e.g. -x -v); + sh allows only a single option argument (`sh -x -v' attempts + to open a file named `-v', and, on SunOS 4.1.4, dumps core. + On Solaris 2.4 and earlier versions, sh goes into an infinite + loop.) + sh exits a script if any builtin fails; bash exits only if one of + the POSIX.2 `special' builtins fails + +C2) How does bash differ from the Korn shell, version ksh88? + +Things bash has or uses that ksh88 does not: + long invocation options + [-+]O invocation option + -l invocation option + `!' reserved word + arithmetic for command: for ((expr1 ; expr2; expr3 )); do list; done + arithmetic in largest machine-supported size (intmax_t) + posix mode and posix conformance + command hashing + tilde expansion for assignment statements that look like $PATH + process substitution with named pipes if /dev/fd is not available + the ${!param} indirect parameter expansion operator + the ${!param*} prefix expansion operator + the ${param:offset[:length]} parameter substring operator + the ${param/pat[/string]} parameter pattern substitution operator + variables: BASH, BASH_VERSION, BASH_VERSINFO, UID, EUID, SHLVL, + TIMEFORMAT, HISTCMD, HOSTTYPE, OSTYPE, MACHTYPE, + HISTFILESIZE, HISTIGNORE, HISTCONTROL, PROMPT_COMMAND, + IGNOREEOF, FIGNORE, INPUTRC, HOSTFILE, DIRSTACK, + PIPESTATUS, HOSTNAME, OPTERR, SHELLOPTS, GLOBIGNORE, + GROUPS, FUNCNAME, histchars, auto_resume + prompt expansion with backslash escapes and command substitution + redirection: &> (stdout and stderr), <<<, [n]<&word-, [n]>&word- + more extensive and extensible editing and programmable completion + builtins: bind, builtin, command, declare, dirs, echo -e/-E, enable, + exec -l/-c/-a, fc -s, export -n/-f/-p, hash, help, history, + jobs -x/-r/-s, kill -s/-n/-l, local, logout, popd, pushd, + read -e/-p/-a/-t/-n/-d/-s, readonly -a/-n/-f/-p, + set -o braceexpand/-o histexpand/-o interactive-comments/ + -o notify/-o physical/-o posix/-o hashall/-o onecmd/ + -h/-B/-C/-b/-H/-P, set +o, suspend, trap -l, type, + typeset -a/-F/-p, ulimit -u, umask -S, alias -p, shopt, + disown, printf, complete, compgen + `!' csh-style history expansion + POSIX.2-style globbing character classes + POSIX.2-style globbing equivalence classes + POSIX.2-style globbing collating symbols + egrep-like extended pattern matching operators + case-insensitive pattern matching and globbing + `**' arithmetic operator to do exponentiation + redirection to /dev/fd/N, /dev/stdin, /dev/stdout, /dev/stderr + arrays of unlimited size + TMOUT is default timeout for `read' and `select' + +Things ksh88 has or uses that bash does not: + tracked aliases (alias -t) + variables: ERRNO, FPATH, EDITOR, VISUAL + co-processes (|&, >&p, <&p) + weirdly-scoped functions + typeset +f to list all function names without definitions + text of command history kept in a file, not memory + builtins: alias -x, cd old new, fc -e -, newgrp, print, + read -p/-s/var?prompt, set -A/-o gmacs/ + -o bgnice/-o markdirs/-o nolog/-o trackall/-o viraw/-s, + typeset -H/-L/-R/-Z/-A/-ft/-fu/-fx/-l/-u/-t, whence + using environment to pass attributes of exported variables + arithmetic evaluation done on arguments to some builtins + reads .profile from $PWD when invoked as login shell + +Implementation differences: + ksh runs last command of a pipeline in parent shell context + bash has brace expansion by default (ksh88 compile-time option) + bash has fixed startup file for all interactive shells; ksh reads $ENV + bash has exported functions + bash command search finds functions before builtins + bash waits for all commands in pipeline to exit before returning status + emacs-mode editing has some slightly different key bindings + +C3) Which new features in ksh-93 are not in bash, and which are? + +New things in ksh-93 not in bash-2.05b: + associative arrays + floating point arithmetic and variables + math library functions + ${!name[sub]} name of subscript for associative array + `.' is allowed in variable names to create a hierarchical namespace + more extensive compound assignment syntax + discipline functions + `sleep' and `getconf' builtins (bash has loadable versions) + typeset -n and `nameref' variables + KEYBD trap + variables: .sh.edchar, .sh.edmode, .sh.edcol, .sh.edtext, .sh.version, + .sh.name, .sh.subscript, .sh.value, .sh.match, HISTEDIT + backreferences in pattern matching (\N) + `&' operator in pattern lists for matching + print -f (bash uses printf) + `fc' has been renamed to `hist' + `.' can execute shell functions + exit statuses between 0 and 255 + set -o pipefail + `+=' variable assignment operator + FPATH and PATH mixing + getopts -a + -I invocation option + DEBUG trap now executed before each simple command, instead of after + printf %H, %P, %T, %Z modifiers, output base for %d + lexical scoping for local variables in `ksh' functions + no scoping for local variables in `POSIX' functions + +New things in ksh-93 present in bash-2.05b: + [n]<&word- and [n]>&word- redirections (combination dup and close) + for (( expr1; expr2; expr3 )) ; do list; done - arithmetic for command + ?:, ++, --, `expr1 , expr2' arithmetic operators + expansions: ${!param}, ${param:offset[:len]}, ${param/pat[/str]}, + ${!param*} + compound array assignment + the `!' reserved word + loadable builtins -- but ksh uses `builtin' while bash uses `enable' + `command', `builtin', `disown' builtins + new $'...' and $"..." quoting + FIGNORE (but bash uses GLOBIGNORE), HISTCMD + set -o notify/-C + changes to kill builtin + read -A (bash uses read -a) + read -t/-d + trap -p + exec -c/-a + `.' restores the positional parameters when it completes + POSIX.2 `test' + umask -S + unalias -a + command and arithmetic substitution performed on PS1, PS4, and ENV + command name completion + ENV processed only for interactive shells + +Section D: Why does bash do some things differently than other Unix shells? + +D1) Why does bash run a different version of `command' than + `which command' says it will? + +On many systems, `which' is actually a csh script that assumes +you're running csh. In tcsh, `which' and its cousin `where' +are builtins. On other Unix systems, `which' is a perl script +that uses the PATH environment variable. + +The csh script version reads the csh startup files from your +home directory and uses those to determine which `command' will +be invoked. Since bash doesn't use any of those startup files, +there's a good chance that your bash environment differs from +your csh environment. The bash `type' builtin does everything +`which' does, and will report correct results for the running +shell. If you're really wedded to the name `which', try adding +the following function definition to your .bashrc: + + which() + { + builtin type "$@" + } + +If you're moving from tcsh and would like to bring `where' along +as well, use this function: + + where() + { + builtin type -a "$@" + } + +D2) Why doesn't bash treat brace expansions exactly like csh? + +The only difference between bash and csh brace expansion is that +bash requires a brace expression to contain at least one unquoted +comma if it is to be expanded. Any brace-surrounded word not +containing an unquoted comma is left unchanged by the brace +expansion code. This affords the greatest degree of sh +compatibility. + +Bash, ksh, zsh, and pd-ksh all implement brace expansion this way. + +D3) Why doesn't bash have csh variable modifiers? + +Posix has specified a more powerful, albeit somewhat more cryptic, +mechanism cribbed from ksh, and bash implements it. + +${parameter%word} + Remove smallest suffix pattern. The WORD is expanded to produce + a pattern. It then expands to the value of PARAMETER, with the + smallest portion of the suffix matched by the pattern deleted. + + x=file.c + echo ${x%.c}.o + -->file.o + +${parameter%%word} + + Remove largest suffix pattern. The WORD is expanded to produce + a pattern. It then expands to the value of PARAMETER, with the + largest portion of the suffix matched by the pattern deleted. + + x=posix/src/std + echo ${x%%/*} + -->posix + +${parameter#word} + Remove smallest prefix pattern. The WORD is expanded to produce + a pattern. It then expands to the value of PARAMETER, with the + smallest portion of the prefix matched by the pattern deleted. + + x=$HOME/src/cmd + echo ${x#$HOME} + -->/src/cmd + +${parameter##word} + Remove largest prefix pattern. The WORD is expanded to produce + a pattern. It then expands to the value of PARAMETER, with the + largest portion of the prefix matched by the pattern deleted. + + x=/one/two/three + echo ${x##*/} + -->three + + +Given + a=/a/b/c/d + b=b.xxx + + csh bash result + --- ---- ------ + $a:h ${a%/*} /a/b/c + $a:t ${a##*/} d + $b:r ${b%.*} b + $b:e ${b##*.} xxx + + +D4) How can I make my csh aliases work when I convert to bash? + +Bash uses a different syntax to support aliases than csh does. +The details can be found in the documentation. We have provided +a shell script which does most of the work of conversion for you; +this script can be found in ./examples/misc/aliasconv.sh. Here is +how you use it: + +Start csh in the normal way for you. (e.g., `csh') + +Pipe the output of `alias' through `aliasconv.sh', saving the +results into `bash_aliases': + + alias | bash aliasconv.sh >bash_aliases + +Edit `bash_aliases', carefully reading through any created +functions. You will need to change the names of some csh specific +variables to the bash equivalents. The script converts $cwd to +$PWD, $term to $TERM, $home to $HOME, $user to $USER, and $prompt +to $PS1. You may also have to add quotes to avoid unwanted +expansion. + +For example, the csh alias: + + alias cd 'cd \!*; echo $cwd' + +is converted to the bash function: + + cd () { command cd "$@"; echo $PWD ; } + +The only thing that needs to be done is to quote $PWD: + + cd () { command cd "$@"; echo "$PWD" ; } + +Merge the edited file into your ~/.bashrc. + +There is an additional, more ambitious, script in +examples/misc/cshtobash that attempts to convert your entire csh +environment to its bash equivalent. This script can be run as +simply `cshtobash' to convert your normal interactive +environment, or as `cshtobash ~/.login' to convert your login +environment. + +D5) How can I pipe standard output and standard error from one command to + another, like csh does with `|&'? + +Use + command 2>&1 | command2 + +The key is to remember that piping is performed before redirection, so +file descriptor 1 points to the pipe when it is duplicated onto file +descriptor 2. + +D6) Now that I've converted from ksh to bash, are there equivalents to + ksh features like autoloaded functions and the `whence' command? + +There are features in ksh-88 and ksh-93 that do not have direct bash +equivalents. Most, however, can be emulated with very little trouble. + +ksh-88 feature Bash equivalent +-------------- --------------- +compiled-in aliases set up aliases in .bashrc; some ksh aliases are + bash builtins (hash, history, type) +coprocesses named pipe pairs (one for read, one for write) +typeset +f declare -F +cd, print, whence function substitutes in examples/functions/kshenv +autoloaded functions examples/functions/autoload is the same as typeset -fu +read var?prompt read -p prompt var + +ksh-93 feature Bash equivalent +-------------- --------------- +sleep, getconf Bash has loadable versions in examples/loadables +${.sh.version} $BASH_VERSION +print -f printf +hist alias hist=fc +$HISTEDIT $FCEDIT + +Section E: How can I get bash to do certain things, and why does bash do + things the way it does? + +E1) Why is the bash builtin `test' slightly different from /bin/test? + +The specific example used here is [ ! x -o x ], which is false. + +Bash's builtin `test' implements the Posix.2 spec, which can be +summarized as follows (the wording is due to David Korn): + +Here is the set of rules for processing test arguments. + + 0 Args: False + 1 Arg: True iff argument is not null. + 2 Args: If first arg is !, True iff second argument is null. + If first argument is unary, then true if unary test is true + Otherwise error. + 3 Args: If second argument is a binary operator, do binary test of $1 $3 + If first argument is !, negate two argument test of $2 $3 + If first argument is `(' and third argument is `)', do the + one-argument test of the second argument. + Otherwise error. + 4 Args: If first argument is !, negate three argument test of $2 $3 $4. + Otherwise unspecified + 5 or more Args: unspecified. (Historical shells would use their + current algorithm). + +The operators -a and -o are considered binary operators for the purpose +of the 3 Arg case. + +As you can see, the test becomes (not (x or x)), which is false. + +E2) Why does bash sometimes say `Broken pipe'? + +If a sequence of commands appears in a pipeline, and one of the +reading commands finishes before the writer has finished, the +writer receives a SIGPIPE signal. Many other shells special-case +SIGPIPE as an exit status in the pipeline and do not report it. +For example, in: + + ps -aux | head + +`head' can finish before `ps' writes all of its output, and ps +will try to write on a pipe without a reader. In that case, bash +will print `Broken pipe' to stderr when ps is killed by a +SIGPIPE. + +You can build a version of bash that will not report SIGPIPE errors +by uncommenting the definition of DONT_REPORT_SIGPIPE in the file +config-top.h. + +E3) When I have terminal escape sequences in my prompt, why does bash + wrap lines at the wrong column? + +Readline, the line editing library that bash uses, does not know +that the terminal escape sequences do not take up space on the +screen. The redisplay code assumes, unless told otherwise, that +each character in the prompt is a `printable' character that +takes up one character position on the screen. + +You can use the bash prompt expansion facility (see the PROMPTING +section in the manual page) to tell readline that sequences of +characters in the prompt strings take up no screen space. + +Use the \[ escape to begin a sequence of non-printing characters, +and the \] escape to signal the end of such a sequence. + +E4) If I pipe the output of a command into `read variable', why doesn't + the output show up in $variable when the read command finishes? + +This has to do with the parent-child relationship between Unix +processes. It affects all commands run in pipelines, not just +simple calls to `read'. For example, piping a command's output +into a `while' loop that repeatedly calls `read' will result in +the same behavior. + +Each element of a pipeline runs in a separate process, a child of +the shell running the pipeline. A subprocess cannot affect its +parent's environment. When the `read' command sets the variable +to the input, that variable is set only in the subshell, not the +parent shell. When the subshell exits, the value of the variable +is lost. + +Many pipelines that end with `read variable' can be converted +into command substitutions, which will capture the output of +a specified command. The output can then be assigned to a +variable: + + grep ^gnu /usr/lib/news/active | wc -l | read ngroup + +can be converted into + + ngroup=$(grep ^gnu /usr/lib/news/active | wc -l) + +This does not, unfortunately, work to split the text among +multiple variables, as read does when given multiple variable +arguments. If you need to do this, you can either use the +command substitution above to read the output into a variable +and chop up the variable using the bash pattern removal +expansion operators or use some variant of the following +approach. + +Say /usr/local/bin/ipaddr is the following shell script: + +#! /bin/sh +host `hostname` | awk '/address/ {print $NF}' + +Instead of using + + /usr/local/bin/ipaddr | read A B C D + +to break the local machine's IP address into separate octets, use + + OIFS="$IFS" + IFS=. + set -- $(/usr/local/bin/ipaddr) + IFS="$OIFS" + A="$1" B="$2" C="$3" D="$4" + +Beware, however, that this will change the shell's positional +parameters. If you need them, you should save them before doing +this. + +This is the general approach -- in most cases you will not need to +set $IFS to a different value. + +Some other user-supplied alternatives include: + +read A B C D << HERE + $(IFS=.; echo $(/usr/local/bin/ipaddr)) +HERE + +and, where process substitution is available, + +read A B C D < <(IFS=.; echo $(/usr/local/bin/ipaddr)) + +E5) I have a bunch of shell scripts that use backslash-escaped characters + in arguments to `echo'. Bash doesn't interpret these characters. Why + not, and how can I make it understand them? + +This is the behavior of echo on most Unix System V machines. + +The bash builtin `echo' is modeled after the 9th Edition +Research Unix version of `echo'. It does not interpret +backslash-escaped characters in its argument strings by default; +it requires the use of the -e option to enable the +interpretation. The System V echo provides no way to disable the +special characters; the bash echo has a -E option to disable +them. + +There is a configuration option that will make bash behave like +the System V echo and interpret things like `\t' by default. Run +configure with the --enable-xpg-echo-default option to turn this +on. Be aware that this will cause some of the tests run when you +type `make tests' to fail. + +There is a shell option, `xpg_echo', settable with `shopt', that will +change the behavior of echo at runtime. Enabling this option turns +on expansion of backslash-escape sequences. + +E6) Why doesn't a while or for loop get suspended when I type ^Z? + +This is a consequence of how job control works on Unix. The only +thing that can be suspended is the process group. This is a single +command or pipeline of commands that the shell forks and executes. + +When you run a while or for loop, the only thing that the shell forks +and executes are any commands in the while loop test and commands in +the loop bodies. These, therefore, are the only things that can be +suspended when you type ^Z. + +If you want to be able to stop the entire loop, you need to put it +within parentheses, which will force the loop into a subshell that +may be stopped (and subsequently restarted) as a single unit. + +E7) What about empty for loops in Makefiles? + +It's fairly common to see constructs like this in automatically-generated +Makefiles: + +SUBDIRS = @SUBDIRS@ + + ... + +subdirs-clean: + for d in ${SUBDIRS}; do \ + ( cd $$d && ${MAKE} ${MFLAGS} clean ) \ + done + +When SUBDIRS is empty, this results in a command like this being passed to +bash: + + for d in ; do + ( cd $d && ${MAKE} ${MFLAGS} clean ) + done + +In versions of bash before bash-2.05a, this was a syntax error. If the +reserved word `in' was present, a word must follow it before the semicolon +or newline. The language in the manual page referring to the list of words +being empty referred to the list after it is expanded. These versions of +bash required that there be at least one word following the `in' when the +construct was parsed. + +The idiomatic Makefile solution is something like: + +SUBDIRS = @SUBDIRS@ + +subdirs-clean: + subdirs=$SUBDIRS ; for d in $$subdirs; do \ + ( cd $$d && ${MAKE} ${MFLAGS} clean ) \ + done + +The latest drafts of the updated POSIX standard have changed this: the +word list is no longer required. Bash versions 2.05a and later accept +the new syntax. + +E8) Why does the arithmetic evaluation code complain about `08'? + +The bash arithmetic evaluation code (used for `let', $(()), (()), and in +other places), interprets a leading `0' in numeric constants as denoting +an octal number, and a leading `0x' as denoting hexadecimal. This is +in accordance with the POSIX.2 spec, section 2.9.2.1, which states that +arithmetic constants should be handled as signed long integers as defined +by the ANSI/ISO C standard. + +The POSIX.2 interpretation committee has confirmed this: + +http://www.pasc.org/interps/unofficial/db/p1003.2/pasc-1003.2-173.html + +E9) Why does the pattern matching expression [A-Z]* match files beginning + with every letter except `z'? + +Bash-2.03, Bash-2.05 and later versions honor the current locale setting +when processing ranges within pattern matching bracket expressions ([A-Z]). +This is what POSIX.2 and SUSv3/XPG6 specify. + +The behavior of the matcher in bash-2.05 and later versions depends on the +current LC_COLLATE setting. Setting this variable to `C' or `POSIX' will +result in the traditional behavior ([A-Z] matches all uppercase ASCII +characters). Many other locales, including the en_US locale (the default +on many US versions of Linux) collate the upper and lower case letters like +this: + + AaBb...Zz + +which means that [A-Z] matches every letter except `z'. Others collate like + + aAbBcC...zZ + +which means that [A-Z] matches every letter except `a'. + +The portable way to specify upper case letters is [:upper:] instead of +A-Z; lower case may be specified as [:lower:] instead of a-z. + +Look at the manual pages for setlocale(3), strcoll(3), and, if it is +present, locale(1). If you have locale(1), you can use it to find +your current locale information even if you do not have any of the +LC_ variables set. + +My advice is to put + + export LC_COLLATE=C + +into /etc/profile and inspect any shell scripts run from cron for +constructs like [A-Z]. This will prevent things like + + rm [A-Z]* + +from removing every file in the current directory except those beginning +with `z' and still allow individual users to change the collation order. +Users may put the above command into their own profiles as well, of course. + +E10) Why does `cd //' leave $PWD as `//'? + +POSIX.2, in its description of `cd', says that *three* or more leading +slashes may be replaced with a single slash when canonicalizing the +current working directory. + +This is, I presume, for historical compatibility. Certain versions of +Unix, and early network file systems, used paths of the form +//hostname/path to access `path' on server `hostname'. + +E11) If I resize my xterm while another program is running, why doesn't bash + notice the change? + +This is another issue that deals with job control. + +The kernel maintains a notion of a current terminal process group. Members +of this process group (processes whose process group ID is equal to the +current terminal process group ID) receive terminal-generated signals like +SIGWINCH. (For more details, see the JOB CONTROL section of the bash +man page.) + +If a terminal is resized, the kernel sends SIGWINCH to each member of +the terminal's current process group (the `foreground' process group). + +When bash is running with job control enabled, each pipeline (which may be +a single command) is run in its own process group, different from bash's +process group. This foreground process group receives the SIGWINCH; bash +does not. Bash has no way of knowing that the terminal has been resized. + +There is a `checkwinsize' option, settable with the `shopt' builtin, that +will cause bash to check the window size and adjust its idea of the +terminal's dimensions each time a process stops or exits and returns control +of the terminal to bash. Enable it with `shopt -s checkwinsize'. + +Section F: Things to watch out for on certain Unix versions + +F1) Why can't I use command line editing in my `cmdtool'? + +The problem is `cmdtool' and bash fighting over the input. When +scrolling is enabled in a cmdtool window, cmdtool puts the tty in +`raw mode' to permit command-line editing using the mouse for +applications that cannot do it themselves. As a result, bash and +cmdtool each try to read keyboard input immediately, with neither +getting enough of it to be useful. + +This mode also causes cmdtool to not implement many of the +terminal functions and control sequences appearing in the +`sun-cmd' termcap entry. For a more complete explanation, see +that file examples/suncmd.termcap in the bash distribution. + +`xterm' is a better choice, and gets along with bash much more +smoothly. + +If you must use cmdtool, you can use the termcap description in +examples/suncmd.termcap. Set the TERMCAP variable to the terminal +description contained in that file, i.e. + +TERMCAP='Mu|sun-cmd:am:bs:km:pt:li#34:co#80:cl=^L:ce=\E[K:cd=\E[J:rs=\E[s:' + +Then export TERMCAP and start a new cmdtool window from that shell. +The bash command-line editing should behave better in the new +cmdtool. If this works, you can put the assignment to TERMCAP +in your bashrc file. + +F2) I built bash on Solaris 2. Why do globbing expansions and filename + completion chop off the first few characters of each filename? + +This is the consequence of building bash on SunOS 5 and linking +with the libraries in /usr/ucblib, but using the definitions +and structures from files in /usr/include. + +The actual conflict is between the dirent structure in +/usr/include/dirent.h and the struct returned by the version of +`readdir' in libucb.a (a 4.3-BSD style `struct direct'). + +Make sure you've got /usr/ccs/bin ahead of /usr/ucb in your $PATH +when configuring and building bash. This will ensure that you +use /usr/ccs/bin/cc or acc instead of /usr/ucb/cc and that you +link with libc before libucb. + +If you have installed the Sun C compiler, you may also need to +put /usr/ccs/bin and /opt/SUNWspro/bin into your $PATH before +/usr/ucb. + +F3) Why does bash dump core after I interrupt username completion or + `~user' tilde expansion on a machine running NIS? + +This is a famous and long-standing bug in the SunOS YP (sorry, NIS) +client library, which is part of libc. + +The YP library code keeps static state -- a pointer into the data +returned from the server. When YP initializes itself (setpwent), +it looks at this pointer and calls free on it if it's non-null. +So far, so good. + +If one of the YP functions is interrupted during getpwent (the +exact function is interpretwithsave()), and returns NULL, the +pointer is freed without being reset to NULL, and the function +returns. The next time getpwent is called, it sees that this +pointer is non-null, calls free, and the bash free() blows up +because it's being asked to free freed memory. + +The traditional Unix mallocs allow memory to be freed multiple +times; that's probably why this has never been fixed. You can +run configure with the `--without-gnu-malloc' option to use +the C library malloc and avoid the problem. + +F4) I'm running SVR4.2. Why is the line erased every time I type `@'? + +The `@' character is the default `line kill' character in most +versions of System V, including SVR4.2. You can change this +character to whatever you want using `stty'. For example, to +change the line kill character to control-u, type + + stty kill ^U + +where the `^' and `U' can be two separate characters. + +F5) Why does bash report syntax errors when my C News scripts use a + redirection before a subshell command? + +The actual command in question is something like + + < file ( command ) + +According to the grammar given in the POSIX.2 standard, this construct +is, in fact, a syntax error. Redirections may only precede `simple +commands'. A subshell construct such as the above is one of the shell's +`compound commands'. A redirection may only follow a compound command. + +This affects the mechanical transformation of commands that use `cat' +to pipe a file into a command (a favorite Useless-Use-Of-Cat topic on +comp.unix.shell). While most commands of the form + + cat file | command + +can be converted to `< file command', shell control structures such as +loops and subshells require `command < file'. + +The file CWRU/sh-redir-hack in the bash-2.05a distribution is an +(unofficial) patch to parse.y that will modify the grammar to +support this construct. It will not apply with `patch'; you must +modify parse.y by hand. Note that if you apply this, you must +recompile with -DREDIRECTION_HACK. This introduces a large +number of reduce/reduce conflicts into the shell grammar. + +F6) Why can't I use vi-mode editing on Red Hat Linux 6.1? + +The short answer is that Red Hat screwed up. + +The long answer is that they shipped an /etc/inputrc that only works +for emacs mode editing, and then screwed all the vi users by setting +INPUTRC to /etc/inputrc in /etc/profile. + +The short fix is to do one of the following: remove or rename +/etc/inputrc, set INPUTRC=~/.inputrc in ~/.bashrc (or .bash_profile, +but make sure you export it if you do), remove the assignment to +INPUTRC from /etc/profile, add + + set keymap emacs + +to the beginning of /etc/inputrc, or bracket the key bindings in +/etc/inputrc with these lines + + $if mode=emacs + [...] + $endif + +F7) Why do bash-2.05a and bash-2.05b fail to compile `printf.def' on + HP/UX 11.x? + +HP/UX's support for long double is imperfect at best. + +GCC will support it without problems, but the HP C library functions +like strtold(3) and printf(3) don't actually work with long doubles. +HP implemented a `long_double' type as a 4-element array of 32-bit +ints, and that is what the library functions use. The ANSI C +`long double' type is a 128-bit floating point scalar. + +The easiest fix, until HP fixes things up, is to edit the generated +config.h and #undef the HAVE_LONG_DOUBLE line. After doing that, +the compilation should complete successfully. + +Section G: How can I get bash to do certain common things? + +G1) How can I get bash to read and display eight-bit characters? + +This is a process requiring several steps. + +First, you must ensure that the `physical' data path is a full eight +bits. For xterms, for example, the `vt100' resources `eightBitInput' +and `eightBitOutput' should be set to `true'. + +Once you have set up an eight-bit path, you must tell the kernel and +tty driver to leave the eighth bit of characters alone when processing +keyboard input. Use `stty' to do this: + + stty cs8 -istrip -parenb + +For old BSD-style systems, you can use + + stty pass8 + +You may also need + + stty even odd + +Finally, you need to tell readline that you will be inputting and +displaying eight-bit characters. You use readline variables to do +this. These variables can be set in your .inputrc or using the bash +`bind' builtin. Here's an example using `bind': + + bash$ bind 'set convert-meta off' + bash$ bind 'set meta-flag on' + bash$ bind 'set output-meta on' + +The `set' commands between the single quotes may also be placed +in ~/.inputrc. + +G2) How do I write a function `x' to replace builtin command `x', but + still invoke the command from within the function? + +This is why the `command' and `builtin' builtins exist. The +`command' builtin executes the command supplied as its first +argument, skipping over any function defined with that name. The +`builtin' builtin executes the builtin command given as its first +argument directly. + +For example, to write a function to replace `cd' that writes the +hostname and current directory to an xterm title bar, use +something like the following: + + cd() + { + builtin cd "$@" && xtitle "$HOST: $PWD" + } + +This could also be written using `command' instead of `builtin'; +the version above is marginally more efficient. + +G3) How can I find the value of a shell variable whose name is the value + of another shell variable? + +Versions of Bash newer than Bash-2.0 support this directly. You can use + + ${!var} + +For example, the following sequence of commands will echo `z': + + var1=var2 + var2=z + echo ${!var1} + +For sh compatibility, use the `eval' builtin. The important +thing to remember is that `eval' expands the arguments you give +it again, so you need to quote the parts of the arguments that +you want `eval' to act on. + +For example, this expression prints the value of the last positional +parameter: + + eval echo \"\$\{$#\}\" + +The expansion of the quoted portions of this expression will be +deferred until `eval' runs, while the `$#' will be expanded +before `eval' is executed. In versions of bash later than bash-2.0, + + echo ${!#} + +does the same thing. + +This is not the same thing as ksh93 `nameref' variables, though the syntax +is similar. I may add namerefs in a future bash version. + +G4) How can I make the bash `time' reserved word print timing output that + looks like the output from my system's /usr/bin/time? + +The bash command timing code looks for a variable `TIMEFORMAT' and +uses its value as a format string to decide how to display the +timing statistics. + +The value of TIMEFORMAT is a string with `%' escapes expanded in a +fashion similar in spirit to printf(3). The manual page explains +the meanings of the escape sequences in the format string. + +If TIMEFORMAT is not set, bash acts as if the following assignment had +been performed: + + TIMEFORMAT=$'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS' + +The POSIX.2 default time format (used by `time -p command') is + + TIMEFORMAT=$'real %2R\nuser %2U\nsys %2S' + +The BSD /usr/bin/time format can be emulated with: + + TIMEFORMAT=$'\t%1R real\t%1U user\t%1S sys' + +The System V /usr/bin/time format can be emulated with: + + TIMEFORMAT=$'\nreal\t%1R\nuser\t%1U\nsys\t%1S' + +The ksh format can be emulated with: + + TIMEFORMAT=$'\nreal\t%2lR\nuser\t%2lU\nsys\t%2lS' + +G5) How do I get the current directory into my prompt? + +Bash provides a number of backslash-escape sequences which are expanded +when the prompt string (PS1 or PS2) is displayed. The full list is in +the manual page. + +The \w expansion gives the full pathname of the current directory, with +a tilde (`~') substituted for the current value of $HOME. The \W +expansion gives the basename of the current directory. To put the full +pathname of the current directory into the path without any tilde +subsitution, use $PWD. Here are some examples: + + PS1='\w$ ' # current directory with tilde + PS1='\W$ ' # basename of current directory + PS1='$PWD$ ' # full pathname of current directory + +The single quotes are important in the final example to prevent $PWD from +being expanded when the assignment to PS1 is performed. + +G6) How can I rename "*.foo" to "*.bar"? + +Use the pattern removal functionality described in D3. The following `for' +loop will do the trick: + + for f in *.foo; do + mv $f ${f%foo}bar + done + +G7) How can I translate a filename from uppercase to lowercase? + +The script examples/functions/lowercase, originally written by John DuBois, +will do the trick. The converse is left as an exercise. + +G8) How can I write a filename expansion (globbing) pattern that will match + all files in the current directory except "." and ".."? + +You must have set the `extglob' shell option using `shopt -s extglob' to use +this: + + echo .!(.|) * + +A solution that works without extended globbing is given in the Unix Shell +FAQ, posted periodically to comp.unix.shell. + +Section H: Where do I go from here? + +H1) How do I report bugs in bash, and where should I look for fixes and + advice? + +Use the `bashbug' script to report bugs. It is built and +installed at the same time as bash. It provides a standard +template for reporting a problem and automatically includes +information about your configuration and build environment. + +`bashbug' sends its reports to bug-bash@gnu.org, which +is a large mailing list gatewayed to the usenet newsgroup gnu.bash.bug. + +Bug fixes, answers to questions, and announcements of new releases +are all posted to gnu.bash.bug. Discussions concerning bash features +and problems also take place there. + +To reach the bash maintainers directly, send mail to +bash-maintainers@gnu.org. + +H2) What kind of bash documentation is there? + +First, look in the doc directory in the bash distribution. It should +contain at least the following files: + +bash.1 an extensive, thorough Unix-style manual page +builtins.1 a manual page covering just bash builtin commands +bashref.texi a reference manual in GNU tex`info format +bashref.info an info version of the reference manual +FAQ this file +article.ms text of an article written for The Linux Journal +readline.3 a man page describing readline + +Postscript, HTML, and ASCII files created from the above source are +available in the documentation distribution. + +There is additional documentation available for anonymous FTP from host +ftp.cwru.edu in the `pub/bash' directory. + +Cameron Newham and Bill Rosenblatt have written a book on bash, published +by O'Reilly and Associates. The book is based on Bill Rosenblatt's Korn +Shell book. The title is ``Learning the Bash Shell'', and the ISBN number +is 1-56592-147-X. Look for it in fine bookstores near you. This book +covers bash-1.14, but has an appendix describing some of the new features +in bash-2.0. + +A second edition of this book is available, published in January, 1998. +The ISBN number is 1-56592-347-2. Look for it in the same fine bookstores +or on the web. + +The GNU Bash Reference Manual has been published as a printed book by +Network Theory Ltd (Paperback, ISBN: 0-9541617-7-7, Feb 2003). It covers +bash-2.0 and is available from most online bookstores (see +http://www.network-theory.co.uk/bash/manual/ for details). The publisher +will donate $1 to the Free Software Foundation for each copy sold. + +H3) What's coming in future versions? + +These are features I hope to include in a future version of bash. + +a better bash debugger (a minimally-tested version is included with bash-2.05b) +associative arrays +co-processes, but with a new-style syntax that looks like function declaration + +H4) What's on the bash `wish list' for future versions? + +These are features that may or may not appear in a future version of bash. + +breaking some of the shell functionality into embeddable libraries +a module system like zsh's, using dynamic loading like builtins +better internationalization using GNU `gettext' +date-stamped command history +a bash programmer's guide with a chapter on creating loadable builtins +a better loadable interface to perl with access to the shell builtins and + variables (contributions gratefully accepted) +ksh93-like `nameref' variables +ksh93-like `+=' variable assignment operator +ksh93-like `xx.yy' variables (including some of the .sh.* variables) and + associated disipline functions +Some of the new ksh93 pattern matching operators, like backreferencing + +H5) When will the next release appear? + +The next version will appear sometime in 2002. Never make predictions. + + +This document is Copyright 1995-2003 by Chester Ramey. + +Permission is hereby granted, without written agreement and +without license or royalty fees, to use, copy, and distribute +this document for any purpose, provided that the above copyright +notice appears in all copies of this document and that the +contents of this document remain unaltered. diff --git a/doc/bash.0 b/doc/bash.0 index eabbb81a4..73926bf88 100644 --- a/doc/bash.0 +++ b/doc/bash.0 @@ -991,19 +991,19 @@ PPAARRAAMMEETTEERRSS BBAASSHH__CCOOMMPPAATT The value is used to set the shell's compatibility level. See - the description of the sshhoopptt bbuuiillttiinn bbeellooww uunnddeerr SSHHEELLLL BBUUIILLTTIINN - CCOOMMMMAANNDDSS ffoorr aa ddeessccrriippttiioonn ooff tthhee vvaarriioouuss ccoommppaattiibbiilliittyy lleevveellss - aanndd tthheeiirr eeffffeeccttss.. TThhee vvaalluuee mmaayy bbee aa ddeecciimmaall nnuummbbeerr ((ee..gg..,, - 44..22)) oorr aann iinntteeggeerr ((ee..gg..,, 4422)) ccoorrrreessppoonnddiinngg ttoo tthhee ddeessiirreedd ccoomm-- - ppaattiibbiilliittyy lleevveell.. IIff BBAASSHH__CCOOMMPPAATT iiss uunnsseett oorr sseett ttoo tthhee eemmppttyy - ssttrriinngg,, tthhee ccoommppaattiibbiilliittyy lleevveell iiss sseett ttoo tthhee ddeeffaauulltt ffoorr tthhee - ccuurrrreenntt vveerrssiioonn.. IIff BBAASSHH__CCOOMMPPAATT iiss sseett ttoo aa vvaalluuee tthhaatt iiss nnoott - oonnee ooff tthhee vvaalliidd ccoommppaattiibbiilliittyy lleevveellss,, tthhee sshheellll pprriinnttss aann eerrrroorr - mmeessssaaggee aanndd sseettss tthhee ccoommppaattiibbiilliittyy lleevveell ttoo tthhee ddeeffaauulltt ffoorr tthhee - ccuurrrreenntt vveerrssiioonn.. TThhee vvaalliidd ccoommppaattiibbiilliittyy lleevveellss ccoorrrreessppoonndd ttoo - tthhee ccoommppaattiibbiilliittyy ooppttiioonnss aacccceepptteedd bbyy tthhee sshhoopptt bbuuiillttiinn - ddeessccrriibbeedd bbeellooww ((ffoorr eexxaammppllee,, ccoommppaatt4422 mmeeaannss tthhaatt 44..22 aanndd 4422 aarree - vvaalliidd vvaalluueess)).. TThhee ccuurrrreenntt vveerrssiioonn iiss aallssoo aa vvaalliidd vvaalluuee.. + 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 @@ -1364,75 +1364,80 @@ PPAARRAAMMEETTEERRSS An array variable is considered set if a subscript has been assigned a value. The null string is a valid value. - 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. Negative subscripts to - indexed arrays are interpreted as described above. Care must be taken - to avoid unwanted side effects caused by pathname expansion. uunnsseett + 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. 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 + 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 + The order of expansions is: brace expansion, tilde expansion, parame- + ter, variable and arithmetic expansion and command substitution (done in a left-to-right fashion), word splitting, and pathname expansion. On systems that can support it, there is an additional expansion avail- able: _p_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n. Only brace expansion, word splitting, and pathname expansion can change - the number of words of the expansion; other expansions expand a single - word to a single word. The only exceptions to this are the expansions + the number of words of the expansion; other expansions expand a single + word to a single word. The only exceptions to this are the expansions of "$$@@" and "$${{_n_a_m_e[[@@]]}}" as explained above (see PPAARRAAMMEETTEERRSS). BBrraaccee EExxppaannssiioonn _B_r_a_c_e _e_x_p_a_n_s_i_o_n is a mechanism by which arbitrary strings may be gener- - ated. This mechanism is similar to _p_a_t_h_n_a_m_e _e_x_p_a_n_s_i_o_n, but the file- + ated. This mechanism is similar to _p_a_t_h_n_a_m_e _e_x_p_a_n_s_i_o_n, but the file- names generated need not exist. Patterns to be brace expanded take the form of an optional _p_r_e_a_m_b_l_e, followed by either a series of comma-sep- - arated strings or a sequence expression between a pair of braces, fol- - lowed by an optional _p_o_s_t_s_c_r_i_p_t. The preamble is prefixed to each + arated strings or a sequence expression between a pair of braces, fol- + lowed by an optional _p_o_s_t_s_c_r_i_p_t. The preamble is prefixed to each string contained within the braces, and the postscript is then appended to each resulting string, expanding left to right. - Brace expansions may be nested. The results of each expanded string - are not sorted; left to right order is preserved. For example, + Brace expansions may be nested. The results of each expanded string + are not sorted; left to right order is preserved. For example, a{{d,c,b}}e expands into `ade ace abe'. - A sequence expression takes the form {{_x...._y[[...._i_n_c_r]]}}, where _x and _y are - either integers or single characters, and _i_n_c_r, an optional increment, - is an integer. When integers are supplied, the expression expands to - each number between _x and _y, inclusive. Supplied integers may be pre- - fixed with _0 to force each term to have the same width. When either _x - or _y begins with a zero, the shell attempts to force all generated - terms to contain the same number of digits, zero-padding where neces- - sary. When characters are supplied, the expression expands to each - character lexicographically between _x and _y, inclusive, using the - default C locale. Note that both _x and _y must be of the same type. - When the increment is supplied, it is used as the difference between + A sequence expression takes the form {{_x...._y[[...._i_n_c_r]]}}, where _x and _y are + either integers or single characters, and _i_n_c_r, an optional increment, + is an integer. When integers are supplied, the expression expands to + each number between _x and _y, inclusive. Supplied integers may be pre- + fixed with _0 to force each term to have the same width. When either _x + or _y begins with a zero, the shell attempts to force all generated + terms to contain the same number of digits, zero-padding where neces- + sary. When characters are supplied, the expression expands to each + character lexicographically between _x and _y, inclusive, using the + default C locale. Note that both _x and _y must be of the same type. + When the increment is supplied, it is used as the difference between each term. The default increment is 1 or -1 as appropriate. Brace expansion is performed before any other expansions, and any char- - acters special to other expansions are preserved in the result. It is - strictly textual. BBaasshh does not apply any syntactic interpretation to + acters special to other expansions are preserved in the result. It is + strictly textual. BBaasshh does not apply any syntactic interpretation to the context of the expansion or the text between the braces. - A correctly-formed brace expansion must contain unquoted opening and - closing braces, and at least one unquoted comma or a valid sequence - expression. Any incorrectly formed brace expansion is left unchanged. + A correctly-formed brace expansion must contain unquoted opening and + closing braces, and at least one unquoted comma or a valid sequence + expression. Any incorrectly formed brace expansion is left unchanged. A {{ or ,, may be quoted with a backslash to prevent its being considered - part of a brace expression. To avoid conflicts with parameter expan- + part of a brace expression. To avoid conflicts with parameter expan- sion, the string $${{ is not considered eligible for brace expansion. This construct is typically used as shorthand when the common prefix of @@ -1442,36 +1447,36 @@ EEXXPPAANNSSIIOONN or chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}} - Brace expansion introduces a slight incompatibility with historical - versions of sshh. sshh does not treat opening or closing braces specially - when they appear as part of a word, and preserves them in the output. - BBaasshh removes braces from words as a consequence of brace expansion. - For example, a word entered to sshh as _f_i_l_e_{_1_,_2_} appears identically in - the output. The same word is output as _f_i_l_e_1 _f_i_l_e_2 after expansion by - bbaasshh. If strict compatibility with sshh is desired, start bbaasshh with the + Brace expansion introduces a slight incompatibility with historical + versions of sshh. sshh does not treat opening or closing braces specially + when they appear as part of a word, and preserves them in the output. + BBaasshh removes braces from words as a consequence of brace expansion. + For example, a word entered to sshh as _f_i_l_e_{_1_,_2_} appears identically in + the output. The same word is output as _f_i_l_e_1 _f_i_l_e_2 after expansion by + bbaasshh. If strict compatibility with sshh is desired, start bbaasshh with the ++BB option or disable brace expansion with the ++BB option to the sseett com- mand (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). TTiillddee EExxppaannssiioonn - If a word begins with an unquoted tilde character (`~~'), all of the - characters preceding the first unquoted slash (or all characters, if - there is no unquoted slash) are considered a _t_i_l_d_e_-_p_r_e_f_i_x. If none of - the characters in the tilde-prefix are quoted, the characters in the - tilde-prefix following the tilde are treated as a possible _l_o_g_i_n _n_a_m_e. - If this login name is the null string, the tilde is replaced with the - value of the shell parameter HHOOMMEE. If HHOOMMEE is unset, the home direc- - tory of the user executing the shell is substituted instead. Other- - wise, the tilde-prefix is replaced with the home directory associated + If a word begins with an unquoted tilde character (`~~'), all of the + characters preceding the first unquoted slash (or all characters, if + there is no unquoted slash) are considered a _t_i_l_d_e_-_p_r_e_f_i_x. If none of + the characters in the tilde-prefix are quoted, the characters in the + tilde-prefix following the tilde are treated as a possible _l_o_g_i_n _n_a_m_e. + If this login name is the null string, the tilde is replaced with the + value of the shell parameter HHOOMMEE. If HHOOMMEE is unset, the home direc- + tory of the user executing the shell is substituted instead. Other- + wise, the tilde-prefix is replaced with the home directory associated with the specified login name. - If the tilde-prefix is a `~+', the value of the shell variable PPWWDD + If the tilde-prefix is a `~+', the value of the shell variable PPWWDD replaces the tilde-prefix. If the tilde-prefix is a `~-', the value of - the shell variable OOLLDDPPWWDD, if it is set, is substituted. If the char- - acters following the tilde in the tilde-prefix consist of a number _N, - optionally prefixed by a `+' or a `-', the tilde-prefix is replaced + the shell variable OOLLDDPPWWDD, if it is set, is substituted. If the char- + acters following the tilde in the tilde-prefix consist of a number _N, + optionally prefixed by a `+' or a `-', the tilde-prefix is replaced with the corresponding element from the directory stack, as it would be displayed by the ddiirrss builtin invoked with the tilde-prefix as an argu- - ment. If the characters following the tilde in the tilde-prefix con- + ment. If the characters following the tilde in the tilde-prefix con- sist of a number without a leading `+' or `-', `+' is assumed. If the login name is invalid, or the tilde expansion fails, the word is @@ -1479,202 +1484,202 @@ 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 filenames with tildes in - assignments to PPAATTHH, MMAAIILLPPAATTHH, and CCDDPPAATTHH, and the shell assigns the + also performed. Consequently, one may use filenames with tildes in + assignments to PPAATTHH, MMAAIILLPPAATTHH, and CCDDPPAATTHH, and the shell assigns the expanded value. PPaarraammeetteerr EExxppaannssiioonn The `$$' character introduces parameter expansion, command substitution, - or arithmetic expansion. The parameter name or symbol to be expanded - may be enclosed in braces, which are optional but serve to protect the - variable to be expanded from characters immediately following it which + or arithmetic expansion. The parameter name or symbol to be expanded + may be enclosed in braces, which are optional but serve to protect the + variable to be expanded from characters immediately following it which could be interpreted as part of the name. - When braces are used, the matching ending brace is the first `}}' not - escaped by a backslash or within a quoted string, and not within an + When braces are used, the matching ending brace is the first `}}' not + escaped by a backslash or within a quoted string, and not within an embedded arithmetic expansion, command substitution, or parameter expansion. ${_p_a_r_a_m_e_t_e_r} - 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 + 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. The _p_a_r_a_m_e_t_e_r is a shell - parameter as described above PPAARRAAMMEETTEERRSS) or an array reference + 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 + 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 + 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- + 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 (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 + When not performing substring expansion, using the forms documented + 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 the - value of _p_a_r_a_m_e_t_e_r starting at the character specified by _o_f_f_- + 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 + 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 + 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- + 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 + 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- + 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 + 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 + 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 + 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@@} - NNaammeess mmaattcchhiinngg pprreeffiixx. Expands to the names of variables whose + NNaammeess mmaattcchhiinngg pprreeffiixx. Expands to the names of variables whose names begin with _p_r_e_f_i_x, separated by the first character of the - IIFFSS special variable. When _@ is used and the expansion appears - within double quotes, each variable name expands to a separate + IIFFSS special variable. When _@ is used and the expansion appears + within double quotes, each variable name expands to a separate word. ${!!_n_a_m_e[_@]} ${!!_n_a_m_e[_*]} - LLiisstt ooff aarrrraayy kkeeyyss. If _n_a_m_e is an array variable, expands to - the list of array indices (keys) assigned in _n_a_m_e. If _n_a_m_e is - not an array, expands to 0 if _n_a_m_e is set and null otherwise. - When _@ is used and the expansion appears within double quotes, + LLiisstt ooff aarrrraayy kkeeyyss. If _n_a_m_e is an array variable, expands to + the list of array indices (keys) assigned in _n_a_m_e. If _n_a_m_e is + not an array, expands to 0 if _n_a_m_e is set and null otherwise. + When _@ is used and the expansion appears within double quotes, each key expands to a separate word. ${##_p_a_r_a_m_e_t_e_r} - PPaarraammeetteerr lleennggtthh. The length in characters of the value of - _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. 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- + PPaarraammeetteerr lleennggtthh. The length in characters of the value of + _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. 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- + 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- + 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- + 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 + to each member of the array in turn, and the expansion is the resultant list. CCoommmmaanndd SSuubbssttiittuuttiioonn @@ -1686,34 +1691,35 @@ EEXXPPAANNSSIIOONN ``_c_o_m_m_a_n_d`` BBaasshh performs the expansion by executing _c_o_m_m_a_n_d and replacing the com- - mand substitution with the standard output of the command, with any + mand substitution with the standard output of the command, with any trailing newlines deleted. Embedded newlines are not deleted, but they - may be removed during word splitting. The command substitution $$((ccaatt + may be removed during word splitting. The command substitution $$((ccaatt _f_i_l_e)) can be replaced by the equivalent but faster $$((<< _f_i_l_e)). - When the old-style backquote form of substitution is used, backslash - retains its literal meaning except when followed by $$, ``, or \\. The + When the old-style backquote form of substitution is used, backslash + retains its literal meaning except when followed by $$, ``, or \\. The first backquote not preceded by a backslash terminates the command sub- - stitution. When using the $(_c_o_m_m_a_n_d) form, all characters between the + stitution. When using the $(_c_o_m_m_a_n_d) form, all characters between the parentheses make up the command; none are treated specially. Command substitutions may be nested. To nest when using the backquoted form, escape the inner backquotes with backslashes. - If the substitution appears within double quotes, word splitting and + If the substitution appears within double quotes, word splitting and pathname expansion are not performed on the results. AArriitthhmmeettiicc EExxppaannssiioonn - Arithmetic expansion allows the evaluation of an arithmetic expression - and the substitution of the result. The format for arithmetic expan- + Arithmetic expansion allows the evaluation of an arithmetic expression + and the substitution of the result. The format for arithmetic expan- sion is: $$((((_e_x_p_r_e_s_s_i_o_n)))) - 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 + 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 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 @@ -4775,162 +4781,163 @@ 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 (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. + 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- + 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), a variable assignment error (such as assign- - ing to a readonly variable) occurs, or an invalid file descrip- + 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), 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 + 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 + 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 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- + 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 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- + 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 _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, + --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 + 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 + 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 + --hh Remember the location of commands as they are looked up for execution. This is enabled by default. - --kk All arguments in the form of assignment statements are - placed in the environment for a command, not just those + --kk All arguments in the form of assignment statements are + placed in the environment for a command, not just those 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). All processes run + --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). 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 + to check a shell script for syntax errors. This is ignored by interactive shells. --oo _o_p_t_i_o_n_-_n_a_m_e The _o_p_t_i_o_n_-_n_a_m_e can be one of the following: @@ -4938,10 +4945,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS Same as --aa. bbrraacceeeexxppaanndd Same as --BB. - eemmaaccss Use an emacs-style command line editing inter- + eemmaaccss Use an emacs-style command line editing inter- face. This is enabled by default when the shell is interactive, unless the shell is started with - the ----nnooeeddiittiinngg option. This also affects the + the ----nnooeeddiittiinngg option. This also affects the editing interface used for rreeaadd --ee. eerrrreexxiitt Same as --ee. eerrrrttrraaccee @@ -4955,8 +4962,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS HHIISSTTOORRYY. This option is on by default in inter- active shells. iiggnnoorreeeeooff - The effect is as if the shell command - ``IGNOREEOF=10'' had been executed (see SShheellll + The effect is as if the shell command + ``IGNOREEOF=10'' had been executed (see SShheellll VVaarriiaabblleess above). kkeeyywwoorrdd Same as --kk. mmoonniittoorr Same as --mm. @@ -4971,341 +4978,341 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS pphhyyssiiccaall Same as --PP. ppiippeeffaaiill - If set, the return value of a pipeline is the - value of the last (rightmost) command to exit - with a non-zero status, or zero if all commands - in the pipeline exit successfully. This option + If set, the return value of a pipeline is the + value of the last (rightmost) command to exit + with a non-zero status, or zero if all commands + in the pipeline exit successfully. This option is disabled by default. - 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). See SSEEEE AALLSSOO + 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). 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. - vvii Use a vi-style command line editing interface. + vvii Use a vi-style command line editing interface. This also affects the editing interface used for rreeaadd --ee. xxttrraaccee Same as --xx. If --oo is supplied with no _o_p_t_i_o_n_-_n_a_m_e, the values of the - current options are printed. If ++oo is supplied with no - _o_p_t_i_o_n_-_n_a_m_e, a series of sseett commands to recreate the - current option settings is displayed on the standard + current options are printed. If ++oo is supplied with no + _o_p_t_i_o_n_-_n_a_m_e, a series of sseett commands to recreate the + current option settings is displayed on the standard output. - --pp Turn on _p_r_i_v_i_l_e_g_e_d mode. In this mode, the $$EENNVV and - $$BBAASSHH__EENNVV files are not processed, shell functions are - not inherited from the environment, and the SSHHEELLLLOOPPTTSS, - BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they + --pp Turn on _p_r_i_v_i_l_e_g_e_d mode. In this mode, the $$EENNVV and + $$BBAASSHH__EENNVV files are not processed, shell functions are + not inherited from the environment, and the SSHHEELLLLOOPPTTSS, + BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they appear in the environment, are ignored. If the shell is - started with the effective user (group) id not equal to - the real user (group) id, and the --pp option is not sup- + started with the effective user (group) id not equal to + the real user (group) id, and the --pp option is not sup- plied, these actions are taken and the effective user id - is set to the real user id. If the --pp option is sup- - plied at startup, the effective user id is not reset. - Turning this option off causes the effective user and + is set to the real user id. If the --pp option is sup- + plied at startup, the effective user id is not reset. + Turning this option off causes the effective user and group ids to be set to the real user and group ids. --tt Exit after reading and executing one command. --uu Treat unset variables and parameters other than the spe- - cial parameters "@" and "*" as an error when performing - parameter expansion. If expansion is attempted on an - unset variable or parameter, the shell prints an error - message, and, if not interactive, exits with a non-zero + cial parameters "@" and "*" as an error when performing + parameter expansion. If expansion is attempted on an + unset variable or parameter, the shell prints an error + message, and, if not interactive, exits with a non-zero status. --vv Print shell input lines as they are read. - --xx After expanding each _s_i_m_p_l_e _c_o_m_m_a_n_d, ffoorr command, ccaassee + --xx After expanding each _s_i_m_p_l_e _c_o_m_m_a_n_d, ffoorr command, ccaassee command, sseelleecctt command, or arithmetic ffoorr command, dis- - play the expanded value of PPSS44, followed by the command + play the expanded value of PPSS44, followed by the command and its expanded arguments or associated word list. - --BB The shell performs brace expansion (see BBrraaccee EExxppaannssiioonn + --BB The shell performs brace expansion (see BBrraaccee EExxppaannssiioonn above). This is on by default. - --CC If set, bbaasshh does not overwrite an existing file with - the >>, >>&&, and <<>> redirection operators. This may be + --CC If set, bbaasshh does not overwrite an existing file with + the >>, >>&&, and <<>> redirection operators. This may be overridden when creating output files by using the redi- rection operator >>|| instead of >>. --EE If set, any trap on EERRRR is inherited by shell functions, - command substitutions, and commands executed in a sub- - shell environment. The EERRRR trap is normally not inher- + command substitutions, and commands executed in a sub- + shell environment. The EERRRR trap is normally not inher- 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 resolve symbolic links when - executing commands such as ccdd that change the current + --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 - chain of directories when performing commands which + chain of directories when performing commands which change the current directory. - --TT If set, any traps on DDEEBBUUGG and RREETTUURRNN are inherited by - shell functions, command substitutions, and commands - executed in a subshell environment. The DDEEBBUUGG and + --TT If set, any traps on DDEEBBUUGG and RREETTUURRNN are inherited by + shell functions, command substitutions, and commands + executed in a subshell environment. The DDEEBBUUGG and RREETTUURRNN traps are normally not inherited in such cases. - ---- If no arguments follow this option, then the positional + ---- If no arguments follow this option, then the positional parameters are unset. Otherwise, the positional parame- - ters are set to the _a_r_gs, even if some of them begin + ters are set to the _a_r_gs, even if some of them begin with a --. - -- Signal the end of options, cause all remaining _a_r_gs to + -- Signal the end of options, cause all remaining _a_r_gs to be assigned to the positional parameters. The --xx and --vv options are turned off. If there are no _a_r_gs, the posi- tional parameters remain unchanged. - The options are off by default unless otherwise noted. Using + - rather than - causes these options to be turned off. The - options can also be specified as arguments to an invocation of - the shell. The current set of options may be found in $$--. The + The options are off by default unless otherwise noted. Using + + rather than - causes these options to be turned off. The + options can also be specified as arguments to an invocation of + the shell. The current set of options may be found in $$--. The return status is always true unless an invalid option is encoun- tered. sshhiifftt [_n] - The positional parameters from _n+1 ... are renamed to $$11 ........ - Parameters represented by the numbers $$## down to $$##-_n+1 are - unset. _n must be a non-negative number less than or equal to - $$##. If _n is 0, no parameters are changed. If _n is not given, - it is assumed to be 1. If _n is greater than $$##, the positional - parameters are not changed. The return status is greater than + The positional parameters from _n+1 ... are renamed to $$11 ........ + Parameters represented by the numbers $$## down to $$##-_n+1 are + unset. _n must be a non-negative number less than or equal to + $$##. If _n is 0, no parameters are changed. If _n is not given, + it is assumed to be 1. If _n is greater than $$##, the positional + parameters are not changed. The return status is greater than 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- + 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: --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 + --qq Suppresses normal output (quiet mode); the return status indicates whether the _o_p_t_n_a_m_e is set or unset. If multi- - ple _o_p_t_n_a_m_e arguments are given with --qq, the return sta- - tus is zero if all _o_p_t_n_a_m_e_s are enabled; non-zero other- + ple _o_p_t_n_a_m_e arguments are given with --qq, the return sta- + tus is zero if all _o_p_t_n_a_m_e_s are enabled; non-zero other- wise. - --oo Restricts the values of _o_p_t_n_a_m_e to be those defined for + --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, sshhoopptt - shows only those options which are set or unset, respectively. - Unless otherwise noted, the sshhoopptt options are disabled (unset) + 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 - options, the return status is zero unless an _o_p_t_n_a_m_e is not a + 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 + options, the return status is zero unless an _o_p_t_n_a_m_e is not a valid shell option. The list of sshhoopptt options is: - aauuttooccdd If set, a command name that is the name of a directory - is executed as if it were the argument to the ccdd com- + aauuttooccdd If set, a command name that is the name of a directory + is executed as if it were the argument to the ccdd com- mand. This option is only used by interactive shells. ccddaabbllee__vvaarrss - If set, an argument to the ccdd builtin command that is - not a directory is assumed to be the name of a variable + If set, an argument to the ccdd builtin command that is + not a directory is assumed to be the name of a variable whose value is the directory to change to. ccddssppeellll If set, minor errors in the spelling of a directory com- - ponent in a ccdd command will be corrected. The errors + 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 filename is printed, and the com- - mand proceeds. This option is only used by interactive + ter, and one character too many. If a correction is + found, the corrected filename is printed, and the com- + mand proceeds. This option is only used by interactive shells. cchheecckkhhaasshh If set, bbaasshh checks that a command found in the hash ta- - ble exists before trying to execute it. If a hashed - command no longer exists, a normal path search is per- + ble exists before trying to execute it. If a hashed + command no longer exists, a normal path search is per- formed. cchheecckkjjoobbss If set, bbaasshh lists the status of any stopped and running - jobs before exiting an interactive shell. If any jobs + jobs before exiting an interactive shell. If any jobs are running, this causes the exit to be deferred until a - second exit is attempted without an intervening command - (see JJOOBB CCOONNTTRROOLL above). The shell always postpones + second exit is attempted without an intervening command + (see JJOOBB CCOONNTTRROOLL above). The shell always postpones exiting if any jobs are stopped. cchheecckkwwiinnssiizzee - If set, bbaasshh checks the window size after each command - and, if necessary, updates the values of LLIINNEESS and CCOOLL-- + If set, bbaasshh checks the window size after each command + and, if necessary, updates the values of LLIINNEESS and CCOOLL-- UUMMNNSS. - ccmmddhhiisstt If set, bbaasshh attempts to save all lines of a multiple- - line command in the same history entry. This allows + ccmmddhhiisstt If set, bbaasshh attempts to save all lines of a multiple- + line command in the same history entry. This allows easy re-editing of multi-line commands. ccoommppaatt3311 If set, bbaasshh changes its behavior to that of version 3.1 - with respect to quoted arguments to the [[[[ conditional + with respect to quoted arguments to the [[[[ conditional 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 + 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 + with respect to locale-specific string comparison when + 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 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 + with respect to locale-specific string comparison when + using the [[[[ conditional command's << and >> operators + (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 - 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 + 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 + 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 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 + 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. + 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 + 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 (see - PPaatttteerrnn MMaattcchhiinngg above) behave as if in the traditional + If set, range expressions used in pattern matching (see + PPaatttteerrnn MMaattcchhiinngg above) behave as if in the traditional C locale when performing comparisons. That is, the cur- - rent locale's collating sequence is not taken into - account, so bb will not collate between AA and BB, and - upper-case and lower-case ASCII characters will collate + rent locale's collating sequence is not taken into + account, so bb will not collate 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 all files and zero or more directories - and subdirectories. If the pattern is followed by a //, + 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-- @@ -5313,50 +5320,50 @@ 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 (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 + 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, + 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. @@ -5373,120 +5380,120 @@ 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 a + 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 + 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, + 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) + 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 + Signals ignored upon entry to the shell cannot be trapped or + reset. Trapped signals that are not being ignored are reset to their original values in a subshell or subshell environment when - one is created. The return status is false if any _s_i_g_s_p_e_c is + one is created. The return status is false if any _s_i_g_s_p_e_c is invalid; otherwise ttrraapp returns true. ttyyppee [--aaffttppPP] _n_a_m_e [_n_a_m_e ...] - With no options, indicate how each _n_a_m_e would be interpreted if + With no options, indicate how each _n_a_m_e would be interpreted if used as a command name. If the --tt option is used, ttyyppee prints a - string which is one of _a_l_i_a_s, _k_e_y_w_o_r_d, _f_u_n_c_t_i_o_n, _b_u_i_l_t_i_n, or - _f_i_l_e if _n_a_m_e is an alias, shell reserved word, function, - builtin, or disk file, respectively. If the _n_a_m_e is not found, - then nothing is printed, and an exit status of false is - returned. If the --pp option is used, ttyyppee either returns the + string which is one of _a_l_i_a_s, _k_e_y_w_o_r_d, _f_u_n_c_t_i_o_n, _b_u_i_l_t_i_n, or + _f_i_l_e if _n_a_m_e is an alias, shell reserved word, function, + builtin, or disk file, respectively. If the _n_a_m_e is not found, + then nothing is printed, and an exit status of false is + returned. If the --pp option is used, ttyyppee either returns the name of the disk file that would be executed if _n_a_m_e were speci- 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, + 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, 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 + 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 + 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 - to processes started by it, on systems that allow such control. + Provides control over the resources available to the shell and + to processes started by it, on systems that allow such control. The --HH and --SS options specify that the hard or soft limit is set - for the given resource. A hard limit cannot be increased by a - non-root user once it is set; a soft limit may be increased up - to the value of the hard limit. If neither --HH nor --SS is speci- + for the given resource. A hard limit cannot be increased by a + non-root user once it is set; a soft limit may be increased up + to the value of the hard limit. If neither --HH nor --SS is speci- fied, both the soft and hard limits are set. The value of _l_i_m_i_t can be a number in the unit specified for the resource or one of the special values hhaarrdd, ssoofftt, or uunnlliimmiitteedd, which stand for the - current hard limit, the current soft limit, and no limit, - respectively. If _l_i_m_i_t is omitted, the current value of the - soft limit of the resource is printed, unless the --HH option is + current hard limit, the current soft limit, and no limit, + respectively. If _l_i_m_i_t is omitted, the current value of the + soft limit of the resource is printed, unless the --HH option is given. When more than one resource is specified, the limit name and unit are printed before the value. Other options are inter- preted as follows: @@ -5495,11 +5502,11 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --cc The maximum size of core files created --dd The maximum size of a process's data segment --ee The maximum scheduling priority ("nice") - --ff The maximum size of files written by the shell and its + --ff The maximum size of files written by the shell and its children --ii The maximum number of pending signals --ll The maximum size that may be locked into memory - --mm The maximum resident set size (many systems do not honor + --mm The maximum resident set size (many systems do not honor this limit) --nn The maximum number of open file descriptors (most systems do not allow this value to be set) @@ -5508,72 +5515,72 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --rr The maximum real-time scheduling priority --ss The maximum stack size --tt The maximum amount of cpu time in seconds - --uu The maximum number of processes available to a single + --uu The maximum number of processes available to a single user - --vv The maximum amount of virtual memory available to the + --vv The maximum amount of virtual memory available to the shell and, on some systems, to its children --xx The maximum number of file locks --TT The maximum number of threads - 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- + 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 - a digit, it is interpreted as an octal number; otherwise it is - interpreted as a symbolic mode mask similar to that accepted by - _c_h_m_o_d(1). If _m_o_d_e is omitted, the current value of the mask is - printed. The --SS option causes the mask to be printed in sym- - bolic form; the default output is an octal number. If the --pp + a digit, it is interpreted as an octal number; otherwise it is + interpreted as a symbolic mode mask similar to that accepted by + _c_h_m_o_d(1). If _m_o_d_e is omitted, the current value of the mask is + printed. The --SS option causes the mask to be printed in sym- + bolic form; the default output is an octal number. If the --pp option is supplied, and _m_o_d_e is omitted, the output is in a form that may be reused as input. The return status is 0 if the mode - was successfully changed or if no _m_o_d_e argument was supplied, + was successfully changed or if no _m_o_d_e argument was supplied, and false otherwise. uunnaalliiaass [-aa] [_n_a_m_e ...] - Remove each _n_a_m_e from the list of defined aliases. If --aa is - supplied, all alias definitions are removed. The return value + Remove each _n_a_m_e from the list of defined aliases. If --aa is + 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] [-nn] [_n_a_m_e ...] - For each _n_a_m_e, remove the corresponding variable or function. + For each _n_a_m_e, remove the corresponding variable or function. 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. 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-- + 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. 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 process and return its termination sta- - tus. 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 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 + Wait for each specified process and return its termination sta- + tus. 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 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 @@ -5582,16 +5589,16 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL +o specifying command names containing // - +o specifying a filename 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- @@ -5600,10 +5607,10 @@ 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 @@ -5613,15 +5620,16 @@ 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) @@ -5637,7 +5645,7 @@ 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 @@ -5651,14 +5659,14 @@ 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: @@ -5669,7 +5677,7 @@ 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 @@ -5686,10 +5694,10 @@ 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. @@ -5698,4 +5706,4 @@ BBUUGGSS -GNU Bash 4.2 2013 March 4 BASH(1) +GNU Bash 4.3 2013 March 21 BASH(1) diff --git a/doc/bash.1 b/doc/bash.1 index 2d306e05f..acac762c6 100644 --- a/doc/bash.1 +++ b/doc/bash.1 @@ -10190,7 +10190,8 @@ script. .TP \fIThe Gnu History Library\fP, Brian Fox and Chet Ramey .TP -\fIPortable Operating System Interface (POSIX) Part 2: Shell and Utilities\fP, IEEE +\fIPortable Operating System Interface (POSIX) Part 2: Shell and Utilities\fP, IEEE -- +http://pubs.opengroup.org/onlinepubs/9699919799/ .TP http://tiswww.case.edu/~chet/bash/POSIX -- a description of posix mode .TP diff --git a/examples/loadables/Makefile.in.save b/examples/loadables/Makefile.in.save new file mode 100644 index 000000000..f6208f5cc --- /dev/null +++ b/examples/loadables/Makefile.in.save @@ -0,0 +1,238 @@ +# +# Simple makefile for the sample loadable builtins +# +# Copyright (C) 1996 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2, or (at your option) +# any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA. + +# Include some boilerplate Gnu makefile definitions. +prefix = @prefix@ + +exec_prefix = @exec_prefix@ +bindir = @bindir@ +libdir = @libdir@ +infodir = @infodir@ +includedir = @includedir@ + +topdir = @top_srcdir@ +BUILD_DIR = @BUILD_DIR@ +srcdir = @srcdir@ +VPATH = .:@srcdir@ + +@SET_MAKE@ +CC = @CC@ +RM = rm -f + +SHELL = @MAKE_SHELL@ + +host_os = @host_os@ +host_cpu = @host_cpu@ +host_vendor = @host_vendor@ + +CFLAGS = @CFLAGS@ +LOCAL_CFLAGS = @LOCAL_CFLAGS@ +DEFS = @DEFS@ +LOCAL_DEFS = @LOCAL_DEFS@ + +CPPFLAGS = @CPPFLAGS@ + +BASHINCDIR = ${topdir}/include + +LIBBUILD = ${BUILD_DIR}/lib + +INTL_LIBSRC = ${topdir}/lib/intl +INTL_BUILDDIR = ${LIBBUILD}/intl +INTL_INC = @INTL_INC@ +LIBINTL_H = @LIBINTL_H@ + +CCFLAGS = $(DEFS) $(LOCAL_DEFS) $(LOCAL_CFLAGS) $(CFLAGS) + +# +# These values are generated for configure by ${topdir}/support/shobj-conf. +# If your system is not supported by that script, but includes facilities for +# dynamic loading of shared objects, please update the script and send the +# changes to bash-maintainers@gnu.org. +# +SHOBJ_CC = @SHOBJ_CC@ +SHOBJ_CFLAGS = @SHOBJ_CFLAGS@ +SHOBJ_LD = @SHOBJ_LD@ +SHOBJ_LDFLAGS = @SHOBJ_LDFLAGS@ +SHOBJ_XLDFLAGS = @SHOBJ_XLDFLAGS@ +SHOBJ_LIBS = @SHOBJ_LIBS@ +SHOBJ_STATUS = @SHOBJ_STATUS@ + +INC = -I. -I.. -I$(topdir) -I$(topdir)/lib -I$(topdir)/builtins \ + -I$(BASHINCDIR) -I$(BUILD_DIR) -I$(LIBBUILD) \ + -I$(BUILD_DIR)/builtins $(INTL_INC) + +.c.o: + $(SHOBJ_CC) $(SHOBJ_CFLAGS) $(CCFLAGS) $(INC) -c -o $@ $< + + +ALLPROG = print truefalse sleep pushd finfo logname basename dirname \ + tty pathchk tee head mkdir rmdir printenv id whoami \ + uname sync push ln unlink cut realpath getconf strftime +OTHERPROG = necho hello cat + +all: $(SHOBJ_STATUS) + +supported: $(ALLPROG) +others: $(OTHERPROG) + +unsupported: + @echo "Your system (${host_os}) is not supported by the" + @echo "${topdir}/support/shobj-conf script." + @echo "If your operating system provides facilities for dynamic" + @echo "loading of shared objects using the dlopen(3) interface," + @echo "please update the script and re-run configure. + @echo "Please send the changes you made to bash-maintainers@gnu.org" + @echo "for inclusion in future bash releases." + +everything: supported others + +print: print.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ print.o $(SHOBJ_LIBS) + +necho: necho.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ necho.o $(SHOBJ_LIBS) + +getconf: getconf.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ getconf.o $(SHOBJ_LIBS) + +hello: hello.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ hello.o $(SHOBJ_LIBS) + +truefalse: truefalse.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ truefalse.o $(SHOBJ_LIBS) + +sleep: sleep.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ sleep.o $(SHOBJ_LIBS) + +finfo: finfo.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ finfo.o $(SHOBJ_LIBS) + +cat: cat.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ cat.o $(SHOBJ_LIBS) + +logname: logname.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ logname.o $(SHOBJ_LIBS) + +basename: basename.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ basename.o $(SHOBJ_LIBS) + +dirname: dirname.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ dirname.o $(SHOBJ_LIBS) + +tty: tty.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ tty.o $(SHOBJ_LIBS) + +pathchk: pathchk.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ pathchk.o $(SHOBJ_LIBS) + +tee: tee.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ tee.o $(SHOBJ_LIBS) + +mkdir: mkdir.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ mkdir.o $(SHOBJ_LIBS) + +rmdir: rmdir.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ rmdir.o $(SHOBJ_LIBS) + +head: head.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ head.o $(SHOBJ_LIBS) + +printenv: printenv.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ printenv.o $(SHOBJ_LIBS) + +id: id.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ id.o $(SHOBJ_LIBS) + +whoami: whoami.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ whoami.o $(SHOBJ_LIBS) + +uname: uname.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ uname.o $(SHOBJ_LIBS) + +sync: sync.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ sync.o $(SHOBJ_LIBS) + +push: push.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ push.o $(SHOBJ_LIBS) + +ln: ln.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ ln.o $(SHOBJ_LIBS) + +unlink: unlink.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ unlink.o $(SHOBJ_LIBS) + +cut: cut.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ cut.o $(SHOBJ_LIBS) + +realpath: realpath.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ realpath.o $(SHOBJ_LIBS) + +strftime: strftime.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ strftime.o $(SHOBJ_LIBS) + +# pushd is a special case. We use the same source that the builtin version +# uses, with special compilation options. +# +pushd.c: ${topdir}/builtins/pushd.def + $(RM) $@ + ${BUILD_DIR}/builtins/mkbuiltins -D ${topdir}/builtins ${topdir}/builtins/pushd.def + +pushd.o: pushd.c + $(RM) $@ + $(SHOBJ_CC) -DHAVE_CONFIG_H -DPUSHD_AND_POPD -DLOADABLE_BUILTIN $(SHOBJ_CFLAGS) $(CFLAGS) $(CPPFLAGS) $(INC) -c -o $@ $< + +pushd: pushd.o + $(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ pushd.o $(SHOBJ_LIBS) + +clean: + $(RM) $(ALLPROG) $(OTHERPROG) *.o + -( cd perl && ${MAKE} ${MFLAGS} $@ ) + +mostlyclean: clean + -( cd perl && ${MAKE} ${MFLAGS} $@ ) + +distclean maintainer-clean: clean + $(RM) Makefile pushd.c + -( cd perl && ${MAKE} ${MFLAGS} $@ ) + +print.o: print.c +truefalse.o: truefalse.c +sleep.o: sleep.c +finfo.o: finfo.c +logname.o: logname.c +basename.o: basename.c +dirname.o: dirname.c +tty.o: tty.c +pathchk.o: pathchk.c +tee.o: tee.c +head.o: head.c +rmdir.o: rmdir.c +necho.o: necho.c +getconf.o: getconf.c +hello.o: hello.c +cat.o: cat.c +printenv.o: printenv.c +id.o: id.c +whoami.o: whoami.c +uname.o: uname.c +sync.o: sync.c +push.o: push.c +mkdir.o: mkdir.c +realpath.o: realpath.c +strftime.o: strftime.c diff --git a/lib/readline/doc/Makefile.old b/lib/readline/doc/Makefile.old new file mode 100644 index 000000000..58d4dd762 --- /dev/null +++ b/lib/readline/doc/Makefile.old @@ -0,0 +1,76 @@ +# This makefile for Readline library documentation is in -*- text -*- mode. +# Emacs likes it that way. +RM = rm -f + +MAKEINFO = makeinfo +TEXI2DVI = texi2dvi +TEXI2HTML = texi2html +QUIETPS = #set this to -q to shut up dvips +DVIPS = dvips -D 300 $(QUIETPS) -o $@ # tricky + +INSTALL_DATA = cp +infodir = /usr/local/info + +RLSRC = rlman.texinfo rluser.texinfo rltech.texinfo +HISTSRC = hist.texinfo hsuser.texinfo hstech.texinfo + +DVIOBJ = readline.dvi history.dvi +INFOOBJ = readline.info history.info +PSOBJ = readline.ps history.ps +HTMLOBJ = readline.html history.html + +all: info dvi html ps +nodvi: info html + +readline.dvi: $(RLSRC) + $(TEXI2DVI) rlman.texinfo + mv rlman.dvi readline.dvi + +readline.info: $(RLSRC) + $(MAKEINFO) --no-split -o $@ rlman.texinfo + +history.dvi: ${HISTSRC} + $(TEXI2DVI) hist.texinfo + mv hist.dvi history.dvi + +history.info: ${HISTSRC} + $(MAKEINFO) --no-split -o $@ hist.texinfo + +readline.ps: readline.dvi + $(RM) $@ + $(DVIPS) readline.dvi + +history.ps: history.dvi + $(RM) $@ + $(DVIPS) history.dvi + +readline.html: ${RLSRC} + $(TEXI2HTML) rlman.texinfo + sed -e 's:rlman.html:readline.html:' -e 's:rlman_toc.html:readline_toc.html:' rlman.html > readline.html + sed -e 's:rlman.html:readline.html:' -e 's:rlman_toc.html:readline_toc.html:' rlman_toc.html > readline_toc.html + $(RM) rlman.html rlman_toc.html + +history.html: ${HISTSRC} + $(TEXI2HTML) hist.texinfo + sed -e 's:hist.html:history.html:' -e 's:hist_toc.html:history_toc.html:' hist.html > history.html + sed -e 's:hist.html:history.html:' -e 's:hist_toc.html:history_toc.html:' hist_toc.html > history_toc.html + $(RM) hist.html hist_toc.html + +info: $(INFOOBJ) +dvi: $(DVIOBJ) +ps: $(PSOBJ) +html: $(HTMLOBJ) + +clean: + $(RM) *.aux *.cp *.fn *.ky *.log *.pg *.toc *.tp *.vr *.cps *.pgs \ + *.fns *.kys *.tps *.vrs *.o core + +distclean: clean +mostlyclean: clean + +maintainer-clean: clean + $(RM) *.dvi *.info *.info-* *.ps *.html + +install: info + ${INSTALL_DATA} readline.info $(infodir)/readline.info + ${INSTALL_DATA} history.info $(infodir)/history.info diff --git a/tests/misc/regress/log.orig b/tests/misc/regress/log.orig new file mode 100644 index 000000000..c1f1e1991 --- /dev/null +++ b/tests/misc/regress/log.orig @@ -0,0 +1,50 @@ +:; ./shx + +sh: +<&$fd ok +nlbq Mon Aug 3 02:45:00 EDT 1992 +bang geoff +quote 712824302 +setbq defmsgid=<1992Aug3.024502.6176@host> +bgwait sleep done... wait 6187 + + +bash: +<&$fd ok +nlbq Mon Aug 3 02:45:09 EDT 1992 +bang geoff +quote 712824311 +setbq defmsgid=<1992Aug3.024512.6212@host> +bgwait sleep done... wait 6223 + + +ash: +<&$fd shx1: 4: Syntax error: Bad fd number +nlbq Mon Aug 3 02:45:19 EDT 1992 +bang geoff +quote getdate: `"now"' not a valid date + +setbq defmsgid=<1992Aug3.` echo 024521 +bgwait sleep done... wait 6241 + + +ksh: +<&$fd ok +nlbq ./shx: 6248 Memory fault - core dumped +bang geoff +quote getdate: `"now"' not a valid date + +setbq defmsgid=<1992Aug3.024530.6257@host> +bgwait no such job: 6265 +wait 6265 +sleep done... + +zsh: +<&$fd ok +nlbq Mon Aug 3 02:45:36 EDT 1992 +bang shx3: event not found: /s/ [4] +quote 712824337 +setbq defmsgid=<..6290@host> +bgwait shx7: unmatched " [9] +sleep done... +:; diff --git a/tests/misc/regress/shx.orig b/tests/misc/regress/shx.orig new file mode 100644 index 000000000..4b3bf2b82 --- /dev/null +++ b/tests/misc/regress/shx.orig @@ -0,0 +1,10 @@ +#! /bin/sh +for cmd in sh bash ash ksh zsh +do + echo + echo $cmd: + for demo in shx? + do + $cmd $demo + done +done