From: Chet Ramey Date: Thu, 2 Oct 2014 14:20:50 +0000 (-0400) Subject: commit bash-20140905 snapshot X-Git-Tag: bash-4.4-alpha~56 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e198129d214e7fd4df5c0adb454233bc99082530;p=thirdparty%2Fbash.git commit bash-20140905 snapshot --- diff --git a/CWRU/CWRU.chlog b/CWRU/CWRU.chlog index cc7ced6bf..21e20af40 100644 --- a/CWRU/CWRU.chlog +++ b/CWRU/CWRU.chlog @@ -6615,3 +6615,76 @@ variables.c recursively) instead of bind_variable_internal, so invalid variable names (like arr[0]) don't get created. Fixes bug reported by + + 9/3 + --- +execute_cmd.c + - evalnest_max,sourcenest_max: initialize from EVALNEST_MAX and + SOURCENEST_MAX, respectively. Feature suggested by + + +config-top.h + - define EVALNEST_MAX and SOURCENEST_MAX to 0 + + 9/6 + --- +bashline.c + - find_cmd_start: fix to (crudely) deal with >| token; even though + skip_to_delim finds `|' as a delimiter, we call it again and use + what the second call finds. Fixes bug reported by Dan Jacobson + + +findcmd.c + - find_in_path_element: if in posix mode, do not expand a literal + tilde in a $PATH element + +doc/bashref.texi + - add change to tilde expansion in $PATH elements to posix mode + description + +builtins/common.h + - ISHELP: new define for builtins that do their own option parsing + and don't use internal_getopt(); checks whether argument is --help + - CHECK_HELPOPT: convenience define to help builtins that do their + own option parsing to check for --help with one line of code + - CASE_HELPOPT: convenience define to help builtins that use + internal_getopt() check for --help with one line of code + +builtins/help.def + - builtin_help: new function, prints out --help output for current + builtin + +builtins/{kill,let,pushd}.def + - add CHECK_HELPOPT to builtins that use ISOPTION; call builtin_help + and return EX_USAGE (kill/let/pushd/popd/dirs) + +builtins/{caller,fg_bg}.def + - use CHECK_HELPOPT to recognize --help, since these builtins perform + checks that can cause them to return before calling no_options + (caller/fg/bg) + +builtins/{exit,return}.def + - use CHECK_HELPOPT to recognize --help before calling get_exitstat() + (return/exit/logout) + +builtins/{break,shift}.def + - use CHECK_HELPOPT to recognize --help before any other checks + (break/continue/shift) + +builtins/bashgetopt.h + - GETOPT_EOF: convenience define + - GETOPT_HELP: new define, to indicate internal_getopt saw --help + +builtins/bashgetopt.c + - internal_getopt: return GETOPT_HELP for --help + +builtins/common.c + - no_options: recognize --help, call builtin_help and return 2 + (builtin/eval/source/./times) + +builtins/command.def + - use CASE_HELPOPT() to handle --help after calling internal_getopt() + +builtins/{colon,echo,test}.def + - do not recognize --help (:/true/false/echo/test +) diff --git a/CWRU/CWRU.chlog~ b/CWRU/CWRU.chlog~ index 8ae78f5f2..184a77f16 100644 --- a/CWRU/CWRU.chlog~ +++ b/CWRU/CWRU.chlog~ @@ -6606,3 +6606,84 @@ execute_command.c: trigger an error and jump back to the top level - {initialize_subshell,execute_subshell_builtin_or_function}: reset sourcenest to 0 in a subshell + + 9/2 + --- +variables.c + - bind_variable: if a nameref expands to an array reference, make + sure that assign_array_element gets called (maybe even + recursively) instead of bind_variable_internal, so invalid variable + names (like arr[0]) don't get created. Fixes bug reported by + + + 9/3 + --- +execute_cmd.c + - evalnest_max,sourcenest_max: initialize from EVALNEST_MAX and + SOURCENEST_MAX, respectively. Feature suggested by + + +config-top.h + - define EVALNEST_MAX and SOURCENEST_MAX to 0 + + 9/6 + --- +bashline.c + - find_cmd_start: fix to (crudely) deal with >| token; even though + skip_to_delim finds `|' as a delimiter, we call it again and use + what the second call finds. Fixes bug reported by Dan Jacobson + + +findcmd.c + - find_in_path_element: if in posix mode, do not expand a literal + tilde in a $PATH element + +doc/bashref.texi + - add change to tilde expansion in $PATH elements to posix mode + description + +builtins/common.h + - ISHELP: new define for builtins that do their own option parsing + and don't use internal_getopt(); checks whether argument is --help + - CHECK_HELPOPT: convenience define to help builtins that do their + own option parsing to check for --help with one line of code + - CASE_HELPOPT: convenience define to help builtins that use + internal_getopt() check for --help with one line of code + +builtins/help.def + - builtin_help: new function, prints out --help output for current + builtin + +builtins/{kill,let,pushd}.def + - add CHECK_HELPOPT to builtins that use ISOPTION; call builtin_help + and return EX_USAGE (kill/let/pushd/popd/dirs) + +builtins/{caller,fg_bg}.def + - use CHECK_HELPOPT to recognize --help, since these builtins perform + checks that can cause them to return before calling no_options + (caller/fg/bg) + +builtins/{exit,return}.def + - use CHECK_HELPOPT to recognize --help before calling get_exitstat() + (return/exit/logout) + +builtins/{break,shift}.def + - use CHECK_HELPOPT to recognize --help before any other checks + (break/continue/shift) + +builtins/bashgetopt.h + - GETOPT_EOF: convenience define + - GETOPT_HELP: new define, to indicate internal_getopt saw --help + +builtins/bashgetopt.c + - internal_getopt: return GETOPT_HELP for --help + +builtins/common.c + - no_options: recognize --help, call builtin_help and return 2 + (builtin/eval/source/./times) + +builtins/command.def + - use CASE_HELPOPT() to handle --help after calling internal_getopt() + +builtins/{colon,echo,test}.def + - do not recognize --help (:/true/false/echo/test) diff --git a/bashline.c b/bashline.c index 1a079dabf..fde9bacde 100644 --- a/bashline.c +++ b/bashline.c @@ -1305,7 +1305,7 @@ static int find_cmd_start (start) int start; { - register int s, os; + register int s, os, ns; os = 0; /* Flags == SD_NOJMP only because we want to skip over command substitutions @@ -1313,7 +1313,18 @@ find_cmd_start (start) command substitutions as individual words. */ while (((s = skip_to_delim (rl_line_buffer, os, COMMAND_SEPARATORS, SD_NOJMP/*|SD_NOSKIPCMD*/)) <= start) && rl_line_buffer[s]) - os = s+1; + { + /* Handle >| token crudely; treat as > not | */ + if (rl_line_buffer[s] == '|' && rl_line_buffer[s-1] == '>') + { + ns = skip_to_delim (rl_line_buffer, s+1, COMMAND_SEPARATORS, SD_NOJMP/*|SD_NOSKIPCMD*/); + if (ns > start || rl_line_buffer[ns] == 0) + return os; + os = ns+1; + continue; + } + os = s+1; + } return os; } diff --git a/bashline.c~ b/bashline.c~ new file mode 100644 index 000000000..f995eee93 --- /dev/null +++ b/bashline.c~ @@ -0,0 +1,4271 @@ +/* bashline.c -- Bash's interface to the readline library. */ + +/* Copyright (C) 1987-2013 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 3 of the License, 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. If not, see . +*/ + +#include "config.h" + +#if defined (READLINE) + +#include "bashtypes.h" +#include "posixstat.h" + +#if defined (HAVE_UNISTD_H) +# include +#endif + +#if defined (HAVE_GRP_H) +# include +#endif + +#if defined (HAVE_NETDB_H) +# include +#endif + +#include + +#include +#include "chartypes.h" +#include "bashansi.h" +#include "bashintl.h" + +#include "shell.h" +#include "input.h" +#include "builtins.h" +#include "bashhist.h" +#include "bashline.h" +#include "execute_cmd.h" +#include "findcmd.h" +#include "pathexp.h" +#include "shmbutil.h" +#include "trap.h" + +#include "builtins/common.h" + +#include +#include +#include + +#include + +#if defined (ALIAS) +# include "alias.h" +#endif + +#if defined (PROGRAMMABLE_COMPLETION) +# include "pcomplete.h" +#endif + +/* These should agree with the defines for emacs_mode and vi_mode in + rldefs.h, even though that's not a public readline header file. */ +#ifndef EMACS_EDITING_MODE +# define NO_EDITING_MODE -1 +# define EMACS_EDITING_MODE 1 +# define VI_EDITING_MODE 0 +#endif + +#define RL_BOOLEAN_VARIABLE_VALUE(s) ((s)[0] == 'o' && (s)[1] == 'n' && (s)[2] == '\0') + +#if defined (BRACE_COMPLETION) +extern int bash_brace_completion __P((int, int)); +#endif /* BRACE_COMPLETION */ + +/* To avoid including curses.h/term.h/termcap.h and that whole mess. */ +#ifdef _MINIX +extern int tputs __P((const char *string, int nlines, void (*outx)(int))); +#else +extern int tputs __P((const char *string, int nlines, int (*outx)(int))); +#endif + +/* Forward declarations */ + +/* Functions bound to keys in Readline for Bash users. */ +static int shell_expand_line __P((int, int)); +static int display_shell_version __P((int, int)); +static int operate_and_get_next __P((int, int)); + +static int bash_ignore_filenames __P((char **)); +static int bash_ignore_everything __P((char **)); + +#if defined (BANG_HISTORY) +static char *history_expand_line_internal __P((char *)); +static int history_expand_line __P((int, int)); +static int tcsh_magic_space __P((int, int)); +#endif /* BANG_HISTORY */ +#ifdef ALIAS +static int alias_expand_line __P((int, int)); +#endif +#if defined (BANG_HISTORY) && defined (ALIAS) +static int history_and_alias_expand_line __P((int, int)); +#endif + +static int bash_forward_shellword __P((int, int)); +static int bash_backward_shellword __P((int, int)); +static int bash_kill_shellword __P((int, int)); +static int bash_backward_kill_shellword __P((int, int)); + +/* Helper functions for Readline. */ +static char *restore_tilde __P((char *, char *)); +static char *maybe_restore_tilde __P((char *, char *)); + +static char *bash_filename_rewrite_hook __P((char *, int)); + +static void bash_directory_expansion __P((char **)); +static int bash_filename_stat_hook __P((char **)); +static int bash_command_name_stat_hook __P((char **)); +static int bash_directory_completion_hook __P((char **)); +static int filename_completion_ignore __P((char **)); +static int bash_push_line __P((void)); + +static int executable_completion __P((const char *, int)); + +static rl_icppfunc_t *save_directory_hook __P((void)); +static void restore_directory_hook __P((rl_icppfunc_t)); + +static void cleanup_expansion_error __P((void)); +static void maybe_make_readline_line __P((char *)); +static void set_up_new_line __P((char *)); + +static int check_redir __P((int)); +static char **attempt_shell_completion __P((const char *, int, int)); +static char *variable_completion_function __P((const char *, int)); +static char *hostname_completion_function __P((const char *, int)); +static char *command_subst_completion_function __P((const char *, int)); + +static void build_history_completion_array __P((void)); +static char *history_completion_generator __P((const char *, int)); +static int dynamic_complete_history __P((int, int)); +static int bash_dabbrev_expand __P((int, int)); + +static void initialize_hostname_list __P((void)); +static void add_host_name __P((char *)); +static void snarf_hosts_from_file __P((char *)); +static char **hostnames_matching __P((char *)); + +static void _ignore_completion_names __P((char **, sh_ignore_func_t *)); +static int name_is_acceptable __P((const char *)); +static int test_for_directory __P((const char *)); +static int return_zero __P((const char *)); + +static char *bash_dequote_filename __P((char *, int)); +static char *quote_word_break_chars __P((char *)); +static void set_filename_bstab __P((const char *)); +static char *bash_quote_filename __P((char *, int, char *)); + +#ifdef _MINIX +static void putx __P((int)); +#else +static int putx __P((int)); +#endif +static int bash_execute_unix_command __P((int, int)); +static void init_unix_command_map __P((void)); +static int isolate_sequence __P((char *, int, int, int *)); + +static int set_saved_history __P((void)); + +#if defined (ALIAS) +static int posix_edit_macros __P((int, int)); +#endif + +static int bash_event_hook __P((void)); + +#if defined (PROGRAMMABLE_COMPLETION) +static int find_cmd_start __P((int)); +static int find_cmd_end __P((int)); +static char *find_cmd_name __P((int, int *, int *)); +static char *prog_complete_return __P((const char *, int)); + +static char **prog_complete_matches; +#endif + +/* Variables used here but defined in other files. */ +#if defined (BANG_HISTORY) +extern int hist_verify; +#endif + +extern int current_command_line_count, saved_command_line_count; +extern int last_command_exit_value; +extern int array_needs_making; +extern int posixly_correct, no_symbolic_links; +extern int sigalrm_seen; +extern char *current_prompt_string, *ps1_prompt; +extern STRING_INT_ALIST word_token_alist[]; +extern sh_builtin_func_t *last_shell_builtin, *this_shell_builtin; + +/* SPECIFIC_COMPLETION_FUNCTIONS specifies that we have individual + completion functions which indicate what type of completion should be + done (at or before point) that can be bound to key sequences with + the readline library. */ +#define SPECIFIC_COMPLETION_FUNCTIONS + +#if defined (SPECIFIC_COMPLETION_FUNCTIONS) +static int bash_specific_completion __P((int, rl_compentry_func_t *)); + +static int bash_complete_filename_internal __P((int)); +static int bash_complete_username_internal __P((int)); +static int bash_complete_hostname_internal __P((int)); +static int bash_complete_variable_internal __P((int)); +static int bash_complete_command_internal __P((int)); + +static int bash_complete_filename __P((int, int)); +static int bash_possible_filename_completions __P((int, int)); +static int bash_complete_username __P((int, int)); +static int bash_possible_username_completions __P((int, int)); +static int bash_complete_hostname __P((int, int)); +static int bash_possible_hostname_completions __P((int, int)); +static int bash_complete_variable __P((int, int)); +static int bash_possible_variable_completions __P((int, int)); +static int bash_complete_command __P((int, int)); +static int bash_possible_command_completions __P((int, int)); + +static char *glob_complete_word __P((const char *, int)); +static int bash_glob_completion_internal __P((int)); +static int bash_glob_complete_word __P((int, int)); +static int bash_glob_expand_word __P((int, int)); +static int bash_glob_list_expansions __P((int, int)); + +#endif /* SPECIFIC_COMPLETION_FUNCTIONS */ + +static int edit_and_execute_command __P((int, int, int, char *)); +#if defined (VI_MODE) +static int vi_edit_and_execute_command __P((int, int)); +static int bash_vi_complete __P((int, int)); +#endif +static int emacs_edit_and_execute_command __P((int, int)); + +/* Non-zero once initalize_readline () has been called. */ +int bash_readline_initialized = 0; + +/* If non-zero, we do hostname completion, breaking words at `@' and + trying to complete the stuff after the `@' from our own internal + host list. */ +int perform_hostname_completion = 1; + +/* If non-zero, we don't do command completion on an empty line. */ +int no_empty_command_completion; + +/* Set FORCE_FIGNORE if you want to honor FIGNORE even if it ignores the + only possible matches. Set to 0 if you want to match filenames if they + are the only possible matches, even if FIGNORE says to. */ +int force_fignore = 1; + +/* Perform spelling correction on directory names during word completion */ +int dircomplete_spelling = 0; + +/* Expand directory names during word/filename completion. */ +#if DIRCOMPLETE_EXPAND_DEFAULT +int dircomplete_expand = 1; +int dircomplete_expand_relpath = 1; +#else +int dircomplete_expand = 0; +int dircomplete_expand_relpath = 0; +#endif + +/* When non-zero, perform `normal' shell quoting on completed filenames + even when the completed name contains a directory name with a shell + variable referene, so dollar signs in a filename get quoted appropriately. + Set to zero to remove dollar sign (and braces or parens as needed) from + the set of characters that will be quoted. */ +int complete_fullquote = 1; + +static char *bash_completer_word_break_characters = " \t\n\"'@><=;|&(:"; +static char *bash_nohostname_word_break_characters = " \t\n\"'><=;|&(:"; +/* )) */ + +static const char *default_filename_quote_characters = " \t\n\\\"'@<>=;|&()#$`?*[!:{~"; /*}*/ +static char *custom_filename_quote_characters = 0; +static char filename_bstab[256]; + +static rl_hook_func_t *old_rl_startup_hook = (rl_hook_func_t *)NULL; + +static int dot_in_path = 0; + +/* Set to non-zero when dabbrev-expand is running */ +static int dabbrev_expand_active = 0; + +/* What kind of quoting is performed by bash_quote_filename: + COMPLETE_DQUOTE = double-quoting the filename + COMPLETE_SQUOTE = single_quoting the filename + COMPLETE_BSQUOTE = backslash-quoting special chars in the filename +*/ +#define COMPLETE_DQUOTE 1 +#define COMPLETE_SQUOTE 2 +#define COMPLETE_BSQUOTE 3 +static int completion_quoting_style = COMPLETE_BSQUOTE; + +/* Flag values for the final argument to bash_default_completion */ +#define DEFCOMP_CMDPOS 1 + +/* Change the readline VI-mode keymaps into or out of Posix.2 compliance. + Called when the shell is put into or out of `posix' mode. */ +void +posix_readline_initialize (on_or_off) + int on_or_off; +{ + if (on_or_off) + rl_variable_bind ("comment-begin", "#"); +#if defined (VI_MODE) + rl_bind_key_in_map (CTRL ('I'), on_or_off ? rl_insert : rl_complete, vi_insertion_keymap); +#endif +} + +void +reset_completer_word_break_chars () +{ + rl_completer_word_break_characters = perform_hostname_completion ? savestring (bash_completer_word_break_characters) : savestring (bash_nohostname_word_break_characters); +} + +/* When this function returns, rl_completer_word_break_characters points to + dynamically allocated memory. */ +int +enable_hostname_completion (on_or_off) + int on_or_off; +{ + int old_value; + char *at, *nv, *nval; + + old_value = perform_hostname_completion; + + if (on_or_off) + { + perform_hostname_completion = 1; + rl_special_prefixes = "$@"; + } + else + { + perform_hostname_completion = 0; + rl_special_prefixes = "$"; + } + + /* Now we need to figure out how to appropriately modify and assign + rl_completer_word_break_characters depending on whether we want + hostname completion on or off. */ + + /* If this is the first time this has been called + (bash_readline_initialized == 0), use the sames values as before, but + allocate new memory for rl_completer_word_break_characters. */ + + if (bash_readline_initialized == 0 && + (rl_completer_word_break_characters == 0 || + rl_completer_word_break_characters == rl_basic_word_break_characters)) + { + if (on_or_off) + rl_completer_word_break_characters = savestring (bash_completer_word_break_characters); + else + rl_completer_word_break_characters = savestring (bash_nohostname_word_break_characters); + } + else + { + /* See if we have anything to do. */ + at = strchr (rl_completer_word_break_characters, '@'); + if ((at == 0 && on_or_off == 0) || (at != 0 && on_or_off != 0)) + return old_value; + + /* We have something to do. Do it. */ + nval = (char *)xmalloc (strlen (rl_completer_word_break_characters) + 1 + on_or_off); + + if (on_or_off == 0) + { + /* Turn it off -- just remove `@' from word break chars. We want + to remove all occurrences of `@' from the char list, so we loop + rather than just copy the rest of the list over AT. */ + for (nv = nval, at = rl_completer_word_break_characters; *at; ) + if (*at != '@') + *nv++ = *at++; + else + at++; + *nv = '\0'; + } + else + { + nval[0] = '@'; + strcpy (nval + 1, rl_completer_word_break_characters); + } + + free (rl_completer_word_break_characters); + rl_completer_word_break_characters = nval; + } + + return (old_value); +} + +/* Called once from parse.y if we are going to use readline. */ +void +initialize_readline () +{ + rl_command_func_t *func; + char kseq[2]; + + if (bash_readline_initialized) + return; + + rl_terminal_name = get_string_value ("TERM"); + rl_instream = stdin; + rl_outstream = stderr; + + /* Allow conditional parsing of the ~/.inputrc file. */ + rl_readline_name = "Bash"; + + /* Add bindable names before calling rl_initialize so they may be + referenced in the various inputrc files. */ + rl_add_defun ("shell-expand-line", shell_expand_line, -1); +#ifdef BANG_HISTORY + rl_add_defun ("history-expand-line", history_expand_line, -1); + rl_add_defun ("magic-space", tcsh_magic_space, -1); +#endif + + rl_add_defun ("shell-forward-word", bash_forward_shellword, -1); + rl_add_defun ("shell-backward-word", bash_backward_shellword, -1); + rl_add_defun ("shell-kill-word", bash_kill_shellword, -1); + rl_add_defun ("shell-backward-kill-word", bash_backward_kill_shellword, -1); + +#ifdef ALIAS + rl_add_defun ("alias-expand-line", alias_expand_line, -1); +# ifdef BANG_HISTORY + rl_add_defun ("history-and-alias-expand-line", history_and_alias_expand_line, -1); +# endif +#endif + + /* Backwards compatibility. */ + rl_add_defun ("insert-last-argument", rl_yank_last_arg, -1); + + rl_add_defun ("operate-and-get-next", operate_and_get_next, -1); + rl_add_defun ("display-shell-version", display_shell_version, -1); + rl_add_defun ("edit-and-execute-command", emacs_edit_and_execute_command, -1); + +#if defined (BRACE_COMPLETION) + rl_add_defun ("complete-into-braces", bash_brace_completion, -1); +#endif + +#if defined (SPECIFIC_COMPLETION_FUNCTIONS) + rl_add_defun ("complete-filename", bash_complete_filename, -1); + rl_add_defun ("possible-filename-completions", bash_possible_filename_completions, -1); + rl_add_defun ("complete-username", bash_complete_username, -1); + rl_add_defun ("possible-username-completions", bash_possible_username_completions, -1); + rl_add_defun ("complete-hostname", bash_complete_hostname, -1); + rl_add_defun ("possible-hostname-completions", bash_possible_hostname_completions, -1); + rl_add_defun ("complete-variable", bash_complete_variable, -1); + rl_add_defun ("possible-variable-completions", bash_possible_variable_completions, -1); + rl_add_defun ("complete-command", bash_complete_command, -1); + rl_add_defun ("possible-command-completions", bash_possible_command_completions, -1); + rl_add_defun ("glob-complete-word", bash_glob_complete_word, -1); + rl_add_defun ("glob-expand-word", bash_glob_expand_word, -1); + rl_add_defun ("glob-list-expansions", bash_glob_list_expansions, -1); +#endif + + rl_add_defun ("dynamic-complete-history", dynamic_complete_history, -1); + rl_add_defun ("dabbrev-expand", bash_dabbrev_expand, -1); + + /* Bind defaults before binding our custom shell keybindings. */ + if (RL_ISSTATE(RL_STATE_INITIALIZED) == 0) + rl_initialize (); + + /* Bind up our special shell functions. */ + rl_bind_key_if_unbound_in_map (CTRL('E'), shell_expand_line, emacs_meta_keymap); + +#ifdef BANG_HISTORY + rl_bind_key_if_unbound_in_map ('^', history_expand_line, emacs_meta_keymap); +#endif + + rl_bind_key_if_unbound_in_map (CTRL ('O'), operate_and_get_next, emacs_standard_keymap); + rl_bind_key_if_unbound_in_map (CTRL ('V'), display_shell_version, emacs_ctlx_keymap); + + /* In Bash, the user can switch editing modes with "set -o [vi emacs]", + so it is not necessary to allow C-M-j for context switching. Turn + off this occasionally confusing behaviour. */ + kseq[0] = CTRL('J'); + kseq[1] = '\0'; + func = rl_function_of_keyseq (kseq, emacs_meta_keymap, (int *)NULL); + if (func == rl_vi_editing_mode) + rl_unbind_key_in_map (CTRL('J'), emacs_meta_keymap); + kseq[0] = CTRL('M'); + func = rl_function_of_keyseq (kseq, emacs_meta_keymap, (int *)NULL); + if (func == rl_vi_editing_mode) + rl_unbind_key_in_map (CTRL('M'), emacs_meta_keymap); +#if defined (VI_MODE) + rl_unbind_key_in_map (CTRL('E'), vi_movement_keymap); +#endif + +#if defined (BRACE_COMPLETION) + rl_bind_key_if_unbound_in_map ('{', bash_brace_completion, emacs_meta_keymap); /*}*/ +#endif /* BRACE_COMPLETION */ + +#if defined (SPECIFIC_COMPLETION_FUNCTIONS) + rl_bind_key_if_unbound_in_map ('/', bash_complete_filename, emacs_meta_keymap); + rl_bind_key_if_unbound_in_map ('/', bash_possible_filename_completions, emacs_ctlx_keymap); + + /* Have to jump through hoops here because there is a default binding for + M-~ (rl_tilde_expand) */ + kseq[0] = '~'; + kseq[1] = '\0'; + func = rl_function_of_keyseq (kseq, emacs_meta_keymap, (int *)NULL); + if (func == 0 || func == rl_tilde_expand) + rl_bind_keyseq_in_map (kseq, bash_complete_username, emacs_meta_keymap); + + rl_bind_key_if_unbound_in_map ('~', bash_possible_username_completions, emacs_ctlx_keymap); + + rl_bind_key_if_unbound_in_map ('@', bash_complete_hostname, emacs_meta_keymap); + rl_bind_key_if_unbound_in_map ('@', bash_possible_hostname_completions, emacs_ctlx_keymap); + + rl_bind_key_if_unbound_in_map ('$', bash_complete_variable, emacs_meta_keymap); + rl_bind_key_if_unbound_in_map ('$', bash_possible_variable_completions, emacs_ctlx_keymap); + + rl_bind_key_if_unbound_in_map ('!', bash_complete_command, emacs_meta_keymap); + rl_bind_key_if_unbound_in_map ('!', bash_possible_command_completions, emacs_ctlx_keymap); + + rl_bind_key_if_unbound_in_map ('g', bash_glob_complete_word, emacs_meta_keymap); + rl_bind_key_if_unbound_in_map ('*', bash_glob_expand_word, emacs_ctlx_keymap); + rl_bind_key_if_unbound_in_map ('g', bash_glob_list_expansions, emacs_ctlx_keymap); + +#endif /* SPECIFIC_COMPLETION_FUNCTIONS */ + + kseq[0] = TAB; + kseq[1] = '\0'; + func = rl_function_of_keyseq (kseq, emacs_meta_keymap, (int *)NULL); + if (func == 0 || func == rl_tab_insert) + rl_bind_key_in_map (TAB, dynamic_complete_history, emacs_meta_keymap); + + /* Tell the completer that we want a crack first. */ + rl_attempted_completion_function = attempt_shell_completion; + + /* Tell the completer that we might want to follow symbolic links or + do other expansion on directory names. */ + set_directory_hook (); + + rl_filename_rewrite_hook = bash_filename_rewrite_hook; + + rl_filename_stat_hook = bash_filename_stat_hook; + + /* Tell the filename completer we want a chance to ignore some names. */ + rl_ignore_some_completions_function = filename_completion_ignore; + + /* Bind C-xC-e to invoke emacs and run result as commands. */ + rl_bind_key_if_unbound_in_map (CTRL ('E'), emacs_edit_and_execute_command, emacs_ctlx_keymap); +#if defined (VI_MODE) + rl_bind_key_if_unbound_in_map ('v', vi_edit_and_execute_command, vi_movement_keymap); +# if defined (ALIAS) + rl_bind_key_if_unbound_in_map ('@', posix_edit_macros, vi_movement_keymap); +# endif + + rl_bind_key_in_map ('\\', bash_vi_complete, vi_movement_keymap); + rl_bind_key_in_map ('*', bash_vi_complete, vi_movement_keymap); + rl_bind_key_in_map ('=', bash_vi_complete, vi_movement_keymap); +#endif + + rl_completer_quote_characters = "'\""; + + /* This sets rl_completer_word_break_characters and rl_special_prefixes + to the appropriate values, depending on whether or not hostname + completion is enabled. */ + enable_hostname_completion (perform_hostname_completion); + + /* characters that need to be quoted when appearing in filenames. */ + rl_filename_quote_characters = default_filename_quote_characters; + set_filename_bstab (rl_filename_quote_characters); + + rl_filename_quoting_function = bash_quote_filename; + rl_filename_dequoting_function = bash_dequote_filename; + rl_char_is_quoted_p = char_is_quoted; + +#if 0 + /* This is superfluous and makes it impossible to use tab completion in + vi mode even when explicitly binding it in ~/.inputrc. sv_strict_posix() + should already have called posix_readline_initialize() when + posixly_correct was set. */ + if (posixly_correct) + posix_readline_initialize (1); +#endif + + bash_readline_initialized = 1; +} + +void +bashline_reinitialize () +{ + bash_readline_initialized = 0; +} + +void +bashline_set_event_hook () +{ + rl_signal_event_hook = bash_event_hook; +} + +void +bashline_reset_event_hook () +{ + rl_signal_event_hook = 0; +} + +/* On Sun systems at least, rl_attempted_completion_function can end up + getting set to NULL, and rl_completion_entry_function set to do command + word completion if Bash is interrupted while trying to complete a command + word. This just resets all the completion functions to the right thing. + It's called from throw_to_top_level(). */ +void +bashline_reset () +{ + tilde_initialize (); + rl_attempted_completion_function = attempt_shell_completion; + rl_completion_entry_function = NULL; + rl_ignore_some_completions_function = filename_completion_ignore; + rl_filename_quote_characters = default_filename_quote_characters; + set_filename_bstab (rl_filename_quote_characters); + + set_directory_hook (); + rl_filename_stat_hook = bash_filename_stat_hook; + + bashline_reset_event_hook (); +} + +/* Contains the line to push into readline. */ +static char *push_to_readline = (char *)NULL; + +/* Push the contents of push_to_readline into the + readline buffer. */ +static int +bash_push_line () +{ + if (push_to_readline) + { + rl_insert_text (push_to_readline); + free (push_to_readline); + push_to_readline = (char *)NULL; + rl_startup_hook = old_rl_startup_hook; + } + return 0; +} + +/* Call this to set the initial text for the next line to read + from readline. */ +int +bash_re_edit (line) + char *line; +{ + FREE (push_to_readline); + + push_to_readline = savestring (line); + old_rl_startup_hook = rl_startup_hook; + rl_startup_hook = bash_push_line; + + return (0); +} + +static int +display_shell_version (count, c) + int count, c; +{ + rl_crlf (); + show_shell_version (0); + putc ('\r', rl_outstream); + fflush (rl_outstream); + rl_on_new_line (); + rl_redisplay (); + return 0; +} + +/* **************************************************************** */ +/* */ +/* Readline Stuff */ +/* */ +/* **************************************************************** */ + +/* If the user requests hostname completion, then simply build a list + of hosts, and complete from that forever more, or at least until + HOSTFILE is unset. */ + +/* THIS SHOULD BE A STRINGLIST. */ +/* The kept list of hostnames. */ +static char **hostname_list = (char **)NULL; + +/* The physical size of the above list. */ +static int hostname_list_size; + +/* The number of hostnames in the above list. */ +static int hostname_list_length; + +/* Whether or not HOSTNAME_LIST has been initialized. */ +int hostname_list_initialized = 0; + +/* Initialize the hostname completion table. */ +static void +initialize_hostname_list () +{ + char *temp; + + temp = get_string_value ("HOSTFILE"); + if (temp == 0) + temp = get_string_value ("hostname_completion_file"); + if (temp == 0) + temp = DEFAULT_HOSTS_FILE; + + snarf_hosts_from_file (temp); + + if (hostname_list) + hostname_list_initialized++; +} + +/* Add NAME to the list of hosts. */ +static void +add_host_name (name) + char *name; +{ + if (hostname_list_length + 2 > hostname_list_size) + { + hostname_list_size = (hostname_list_size + 32) - (hostname_list_size % 32); + hostname_list = strvec_resize (hostname_list, hostname_list_size); + } + + hostname_list[hostname_list_length++] = savestring (name); + hostname_list[hostname_list_length] = (char *)NULL; +} + +#define cr_whitespace(c) ((c) == '\r' || (c) == '\n' || whitespace(c)) + +static void +snarf_hosts_from_file (filename) + char *filename; +{ + FILE *file; + char *temp, buffer[256], name[256]; + register int i, start; + + file = fopen (filename, "r"); + if (file == 0) + return; + + while (temp = fgets (buffer, 255, file)) + { + /* Skip to first character. */ + for (i = 0; buffer[i] && cr_whitespace (buffer[i]); i++) + ; + + /* If comment or blank line, ignore. */ + if (buffer[i] == '\0' || buffer[i] == '#') + continue; + + /* If `preprocessor' directive, do the include. */ + if (strncmp (buffer + i, "$include ", 9) == 0) + { + char *incfile, *t; + + /* Find start of filename. */ + for (incfile = buffer + i + 9; *incfile && whitespace (*incfile); incfile++) + ; + + /* Find end of filename. */ + for (t = incfile; *t && cr_whitespace (*t) == 0; t++) + ; + + *t = '\0'; + + snarf_hosts_from_file (incfile); + continue; + } + + /* Skip internet address if present. */ + if (DIGIT (buffer[i])) + for (; buffer[i] && cr_whitespace (buffer[i]) == 0; i++); + + /* Gobble up names. Each name is separated with whitespace. */ + while (buffer[i]) + { + for (; cr_whitespace (buffer[i]); i++) + ; + if (buffer[i] == '\0' || buffer[i] == '#') + break; + + /* Isolate the current word. */ + for (start = i; buffer[i] && cr_whitespace (buffer[i]) == 0; i++) + ; + if (i == start) + continue; + strncpy (name, buffer + start, i - start); + name[i - start] = '\0'; + add_host_name (name); + } + } + fclose (file); +} + +/* Return the hostname list. */ +char ** +get_hostname_list () +{ + if (hostname_list_initialized == 0) + initialize_hostname_list (); + return (hostname_list); +} + +void +clear_hostname_list () +{ + register int i; + + if (hostname_list_initialized == 0) + return; + for (i = 0; i < hostname_list_length; i++) + free (hostname_list[i]); + hostname_list_length = hostname_list_initialized = 0; +} + +/* Return a NULL terminated list of hostnames which begin with TEXT. + Initialize the hostname list the first time if necessary. + The array is malloc ()'ed, but not the individual strings. */ +static char ** +hostnames_matching (text) + char *text; +{ + register int i, len, nmatch, rsize; + char **result; + + if (hostname_list_initialized == 0) + initialize_hostname_list (); + + if (hostname_list_initialized == 0) + return ((char **)NULL); + + /* Special case. If TEXT consists of nothing, then the whole list is + what is desired. */ + if (*text == '\0') + { + result = strvec_create (1 + hostname_list_length); + for (i = 0; i < hostname_list_length; i++) + result[i] = hostname_list[i]; + result[i] = (char *)NULL; + return (result); + } + + /* Scan until found, or failure. */ + len = strlen (text); + result = (char **)NULL; + for (i = nmatch = rsize = 0; i < hostname_list_length; i++) + { + if (STREQN (text, hostname_list[i], len) == 0) + continue; + + /* OK, it matches. Add it to the list. */ + if (nmatch >= (rsize - 1)) + { + rsize = (rsize + 16) - (rsize % 16); + result = strvec_resize (result, rsize); + } + + result[nmatch++] = hostname_list[i]; + } + if (nmatch) + result[nmatch] = (char *)NULL; + return (result); +} + +/* The equivalent of the Korn shell C-o operate-and-get-next-history-line + editing command. */ +static int saved_history_line_to_use = -1; +static int last_saved_history_line = -1; + +#define HISTORY_FULL() (history_is_stifled () && history_length >= history_max_entries) + +static int +set_saved_history () +{ + /* XXX - compensate for assumption that history was `shuffled' if it was + actually not. */ + if (HISTORY_FULL () && + hist_last_line_added == 0 && + saved_history_line_to_use < history_length - 1) + saved_history_line_to_use++; + + if (saved_history_line_to_use >= 0) + { + rl_get_previous_history (history_length - saved_history_line_to_use, 0); + last_saved_history_line = saved_history_line_to_use; + } + saved_history_line_to_use = -1; + rl_startup_hook = old_rl_startup_hook; + return (0); +} + +static int +operate_and_get_next (count, c) + int count, c; +{ + int where; + + /* Accept the current line. */ + rl_newline (1, c); + + /* Find the current line, and find the next line to use. */ + where = where_history (); + + if (HISTORY_FULL () || (where >= history_length - 1)) + saved_history_line_to_use = where; + else + saved_history_line_to_use = where + 1; + + old_rl_startup_hook = rl_startup_hook; + rl_startup_hook = set_saved_history; + + return 0; +} + +/* This vi mode command causes VI_EDIT_COMMAND to be run on the current + command being entered (if no explicit argument is given), otherwise on + a command from the history file. */ + +#define VI_EDIT_COMMAND "fc -e \"${VISUAL:-${EDITOR:-vi}}\"" +#define EMACS_EDIT_COMMAND "fc -e \"${VISUAL:-${EDITOR:-emacs}}\"" +#define POSIX_VI_EDIT_COMMAND "fc -e vi" + +static int +edit_and_execute_command (count, c, editing_mode, edit_command) + int count, c, editing_mode; + char *edit_command; +{ + char *command, *metaval; + int r, rrs, metaflag; + sh_parser_state_t ps; + + rrs = rl_readline_state; + saved_command_line_count = current_command_line_count; + + /* Accept the current line. */ + rl_newline (1, c); + + if (rl_explicit_arg) + { + command = (char *)xmalloc (strlen (edit_command) + 8); + sprintf (command, "%s %d", edit_command, count); + } + else + { + /* Take the command we were just editing, add it to the history file, + then call fc to operate on it. We have to add a dummy command to + the end of the history because fc ignores the last command (assumes + it's supposed to deal with the command before the `fc'). */ + /* This breaks down when using command-oriented history and are not + finished with the command, so we should not ignore the last command */ + using_history (); + current_command_line_count++; /* for rl_newline above */ + bash_add_history (rl_line_buffer); + current_command_line_count = 0; /* for dummy history entry */ + bash_add_history (""); + history_lines_this_session++; + using_history (); + command = savestring (edit_command); + } + + metaval = rl_variable_value ("input-meta"); + metaflag = RL_BOOLEAN_VARIABLE_VALUE (metaval); + + /* Now, POSIX.1-2001 and SUSv3 say that the commands executed from the + temporary file should be placed into the history. We don't do that + yet. */ + if (rl_deprep_term_function) + (*rl_deprep_term_function) (); + save_parser_state (&ps); + r = parse_and_execute (command, (editing_mode == VI_EDITING_MODE) ? "v" : "C-xC-e", SEVAL_NOHIST); + restore_parser_state (&ps); + if (rl_prep_term_function) + (*rl_prep_term_function) (metaflag); + + current_command_line_count = saved_command_line_count; + + /* Now erase the contents of the current line and undo the effects of the + rl_accept_line() above. We don't even want to make the text we just + executed available for undoing. */ + rl_line_buffer[0] = '\0'; /* XXX */ + rl_point = rl_end = 0; + rl_done = 0; + rl_readline_state = rrs; + + rl_forced_update_display (); + + return r; +} + +#if defined (VI_MODE) +static int +vi_edit_and_execute_command (count, c) + int count, c; +{ + if (posixly_correct) + return (edit_and_execute_command (count, c, VI_EDITING_MODE, POSIX_VI_EDIT_COMMAND)); + else + return (edit_and_execute_command (count, c, VI_EDITING_MODE, VI_EDIT_COMMAND)); +} +#endif /* VI_MODE */ + +static int +emacs_edit_and_execute_command (count, c) + int count, c; +{ + return (edit_and_execute_command (count, c, EMACS_EDITING_MODE, EMACS_EDIT_COMMAND)); +} + +#if defined (ALIAS) +static int +posix_edit_macros (count, key) + int count, key; +{ + int c; + char alias_name[3], *alias_value, *macro; + + c = rl_read_key (); + alias_name[0] = '_'; + alias_name[1] = c; + alias_name[2] = '\0'; + + alias_value = get_alias_value (alias_name); + if (alias_value && *alias_value) + { + macro = savestring (alias_value); + rl_push_macro_input (macro); + } + return 0; +} +#endif + +/* Bindable commands that move `shell-words': that is, sequences of + non-unquoted-metacharacters. */ + +#define WORDDELIM(c) (shellmeta(c) || shellblank(c)) + +static int +bash_forward_shellword (count, key) + int count, key; +{ + size_t slen; + int sindex, c, p; + DECLARE_MBSTATE; + + if (count < 0) + return (bash_backward_shellword (-count, key)); + + /* The tricky part of this is deciding whether or not the first character + we're on is an unquoted metacharacter. Not completely handled yet. */ + /* XXX - need to test this stuff with backslash-escaped shell + metacharacters and unclosed single- and double-quoted strings. */ + + p = rl_point; + slen = rl_end; + + while (count) + { + if (p == rl_end) + { + rl_point = rl_end; + return 0; + } + + /* Are we in a quoted string? If we are, move to the end of the quoted + string and continue the outer loop. We only want quoted strings, not + backslash-escaped characters, but char_is_quoted doesn't + differentiate. */ + if (char_is_quoted (rl_line_buffer, p) && p > 0 && rl_line_buffer[p-1] != '\\') + { + do + ADVANCE_CHAR (rl_line_buffer, slen, p); + while (p < rl_end && char_is_quoted (rl_line_buffer, p)); + count--; + continue; + } + + /* Rest of code assumes we are not in a quoted string. */ + /* Move forward until we hit a non-metacharacter. */ + while (p < rl_end && (c = rl_line_buffer[p]) && WORDDELIM (c)) + { + switch (c) + { + default: + ADVANCE_CHAR (rl_line_buffer, slen, p); + continue; /* straight back to loop, don't increment p */ + case '\\': + if (p < rl_end && rl_line_buffer[p]) + ADVANCE_CHAR (rl_line_buffer, slen, p); + break; + case '\'': + p = skip_to_delim (rl_line_buffer, ++p, "'", SD_NOJMP); + break; + case '"': + p = skip_to_delim (rl_line_buffer, ++p, "\"", SD_NOJMP); + break; + } + + if (p < rl_end) + p++; + } + + if (rl_line_buffer[p] == 0 || p == rl_end) + { + rl_point = rl_end; + rl_ding (); + return 0; + } + + /* Now move forward until we hit a non-quoted metacharacter or EOL */ + while (p < rl_end && (c = rl_line_buffer[p]) && WORDDELIM (c) == 0) + { + switch (c) + { + default: + ADVANCE_CHAR (rl_line_buffer, slen, p); + continue; /* straight back to loop, don't increment p */ + case '\\': + if (p < rl_end && rl_line_buffer[p]) + ADVANCE_CHAR (rl_line_buffer, slen, p); + break; + case '\'': + p = skip_to_delim (rl_line_buffer, ++p, "'", SD_NOJMP); + break; + case '"': + p = skip_to_delim (rl_line_buffer, ++p, "\"", SD_NOJMP); + break; + } + + if (p < rl_end) + p++; + } + + if (p == rl_end || rl_line_buffer[p] == 0) + { + rl_point = rl_end; + return (0); + } + + count--; + } + + rl_point = p; + return (0); +} + +static int +bash_backward_shellword (count, key) + int count, key; +{ + size_t slen; + int sindex, c, p; + DECLARE_MBSTATE; + + if (count < 0) + return (bash_forward_shellword (-count, key)); + + p = rl_point; + slen = rl_end; + + while (count) + { + if (p == 0) + { + rl_point = 0; + return 0; + } + + /* Move backward until we hit a non-metacharacter. */ + while (p > 0) + { + c = rl_line_buffer[p]; + if (WORDDELIM (c) && char_is_quoted (rl_line_buffer, p) == 0) + BACKUP_CHAR (rl_line_buffer, slen, p); + break; + } + + if (p == 0) + { + rl_point = 0; + return 0; + } + + /* Now move backward until we hit a metacharacter or BOL. */ + while (p > 0) + { + c = rl_line_buffer[p]; + if (WORDDELIM (c) && char_is_quoted (rl_line_buffer, p) == 0) + break; + BACKUP_CHAR (rl_line_buffer, slen, p); + } + + count--; + } + + rl_point = p; + return 0; +} + +static int +bash_kill_shellword (count, key) + int count, key; +{ + int p; + + if (count < 0) + return (bash_backward_kill_shellword (-count, key)); + + p = rl_point; + bash_forward_shellword (count, key); + + if (rl_point != p) + rl_kill_text (p, rl_point); + + rl_point = p; + if (rl_editing_mode == 1) /* 1 == emacs_mode */ + rl_mark = rl_point; + + return 0; +} + +static int +bash_backward_kill_shellword (count, key) + int count, key; +{ + int p; + + if (count < 0) + return (bash_kill_shellword (-count, key)); + + p = rl_point; + bash_backward_shellword (count, key); + + if (rl_point != p) + rl_kill_text (p, rl_point); + + if (rl_editing_mode == 1) /* 1 == emacs_mode */ + rl_mark = rl_point; + + return 0; +} + + +/* **************************************************************** */ +/* */ +/* How To Do Shell Completion */ +/* */ +/* **************************************************************** */ + +#define COMMAND_SEPARATORS ";|&{(`" +/* )} */ +#define COMMAND_SEPARATORS_PLUS_WS ";|&{(` \t" +/* )} */ + +/* check for redirections and other character combinations that are not + command separators */ +static int +check_redir (ti) + int ti; +{ + register int this_char, prev_char; + + /* Handle the two character tokens `>&', `<&', and `>|'. + We are not in a command position after one of these. */ + this_char = rl_line_buffer[ti]; + prev_char = rl_line_buffer[ti - 1]; + + if ((this_char == '&' && (prev_char == '<' || prev_char == '>')) || + (this_char == '|' && prev_char == '>')) + return (1); + else if (this_char == '{' && prev_char == '$') /*}*/ + return (1); +#if 0 /* Not yet */ + else if (this_char == '(' && prev_char == '$') /*)*/ + return (1); + else if (this_char == '(' && prev_char == '<') /*)*/ + return (1); +#if defined (EXTENDED_GLOB) + else if (extended_glob && this_char == '(' && prev_char == '!') /*)*/ + return (1); +#endif +#endif + else if (char_is_quoted (rl_line_buffer, ti)) + return (1); + return (0); +} + +#if defined (PROGRAMMABLE_COMPLETION) +/* + * XXX - because of the <= start test, and setting os = s+1, this can + * potentially return os > start. This is probably not what we want to + * happen, but fix later after 2.05a-release. + */ +static int +find_cmd_start (start) + int start; +{ + register int s, os, ns; + + os = 0; + /* Flags == SD_NOJMP only because we want to skip over command substitutions + in assignment statements. Have to test whether this affects `standalone' + command substitutions as individual words. */ + while (((s = skip_to_delim (rl_line_buffer, os, COMMAND_SEPARATORS, SD_NOJMP/*|SD_NOSKIPCMD*/)) <= start) && + rl_line_buffer[s]) + { + /* Handle >| token crudely; treat as > not | */ + if (rl_line_buffer[s] == '|' && rl_line_buffer[s-1] == '>') + { + ns = skip_to_delim (rl_line_buffer, s+1, COMMAND_SEPARATORS, SD_NOJMP/*|SD_NOSKIPCMD*/); + if (ns > start || rl_line_buffer[ns] == 0) + return os; + } + os = s+1; + } + return os; +} + +static int +find_cmd_end (end) + int end; +{ + register int e; + + e = skip_to_delim (rl_line_buffer, end, COMMAND_SEPARATORS, SD_NOJMP); + return e; +} + +static char * +find_cmd_name (start, sp, ep) + int start; + int *sp, *ep; +{ + char *name; + register int s, e; + + for (s = start; whitespace (rl_line_buffer[s]); s++) + ; + + /* skip until a shell break character */ + e = skip_to_delim (rl_line_buffer, s, "()<>;&| \t\n", SD_NOJMP); + + name = substring (rl_line_buffer, s, e); + + if (sp) + *sp = s; + if (ep) + *ep = e; + + return (name); +} + +static char * +prog_complete_return (text, matchnum) + const char *text; + int matchnum; +{ + static int ind; + + if (matchnum == 0) + ind = 0; + + if (prog_complete_matches == 0 || prog_complete_matches[ind] == 0) + return (char *)NULL; + return (prog_complete_matches[ind++]); +} + +#endif /* PROGRAMMABLE_COMPLETION */ + +/* Try and catch completion attempts that are syntax errors or otherwise + invalid. */ +static int +invalid_completion (text, ind) + const char *text; + int ind; +{ + int pind; + + /* If we don't catch these here, the next clause will */ + if (ind > 0 && rl_line_buffer[ind] == '(' && /*)*/ + member (rl_line_buffer[ind-1], "$<>")) + return 0; + + pind = ind - 1; + while (pind > 0 && whitespace (rl_line_buffer[pind])) + pind--; + /* If we have only whitespace preceding a paren, it's valid */ + if (ind >= 0 && pind <= 0 && rl_line_buffer[ind] == '(') /*)*/ + return 0; + /* Flag the invalid completions, which are mostly syntax errors */ + if (ind > 0 && rl_line_buffer[ind] == '(' && /*)*/ + member (rl_line_buffer[pind], COMMAND_SEPARATORS) == 0) + return 1; + + return 0; +} + +/* Do some completion on TEXT. The indices of TEXT in RL_LINE_BUFFER are + at START and END. Return an array of matches, or NULL if none. */ +static char ** +attempt_shell_completion (text, start, end) + const char *text; + int start, end; +{ + int in_command_position, ti, saveti, qc, dflags; + char **matches, *command_separator_chars; +#if defined (PROGRAMMABLE_COMPLETION) + int have_progcomps, was_assignment; +#endif + + command_separator_chars = COMMAND_SEPARATORS; + matches = (char **)NULL; + rl_ignore_some_completions_function = filename_completion_ignore; + + rl_filename_quote_characters = default_filename_quote_characters; + set_filename_bstab (rl_filename_quote_characters); + set_directory_hook (); + rl_filename_stat_hook = bash_filename_stat_hook; + + /* Determine if this could be a command word. It is if it appears at + the start of the line (ignoring preceding whitespace), or if it + appears after a character that separates commands. It cannot be a + command word if we aren't at the top-level prompt. */ + ti = start - 1; + saveti = qc = -1; + + while ((ti > -1) && (whitespace (rl_line_buffer[ti]))) + ti--; + +#if 1 + /* If this is an open quote, maybe we're trying to complete a quoted + command name. */ + if (ti >= 0 && (rl_line_buffer[ti] == '"' || rl_line_buffer[ti] == '\'')) + { + qc = rl_line_buffer[ti]; + saveti = ti--; + while (ti > -1 && (whitespace (rl_line_buffer[ti]))) + ti--; + } +#endif + + in_command_position = 0; + if (ti < 0) + { + /* Only do command completion at the start of a line when we + are prompting at the top level. */ + if (current_prompt_string == ps1_prompt) + in_command_position++; + else if (parser_in_command_position ()) + in_command_position++; + } + else if (member (rl_line_buffer[ti], command_separator_chars)) + { + in_command_position++; + + if (check_redir (ti) == 1) + in_command_position = 0; + } + else + { + /* This still could be in command position. It is possible + that all of the previous words on the line are variable + assignments. */ + } + + if (in_command_position && invalid_completion (text, ti)) + { + rl_attempted_completion_over = 1; + return ((char **)NULL); + } + + /* Check that we haven't incorrectly flagged a closed command substitution + as indicating we're in a command position. */ + if (in_command_position && ti >= 0 && rl_line_buffer[ti] == '`' && + *text != '`' && unclosed_pair (rl_line_buffer, end, "`") == 0) + in_command_position = 0; + + /* Special handling for command substitution. If *TEXT is a backquote, + it can be the start or end of an old-style command substitution, or + unmatched. If it's unmatched, both calls to unclosed_pair will + succeed. Don't bother if readline found a single quote and we are + completing on the substring. */ + if (*text == '`' && rl_completion_quote_character != '\'' && + (in_command_position || (unclosed_pair (rl_line_buffer, start, "`") && + unclosed_pair (rl_line_buffer, end, "`")))) + matches = rl_completion_matches (text, command_subst_completion_function); + +#if defined (PROGRAMMABLE_COMPLETION) + /* Attempt programmable completion. */ + have_progcomps = prog_completion_enabled && (progcomp_size () > 0); + if (matches == 0 && (in_command_position == 0 || text[0] == '\0') && + current_prompt_string == ps1_prompt) + { + int s, e, s1, e1, os, foundcs; + char *n; + + /* XXX - don't free the members */ + if (prog_complete_matches) + free (prog_complete_matches); + prog_complete_matches = (char **)NULL; + + os = start; + n = 0; + s = find_cmd_start (os); + e = find_cmd_end (end); + do + { + /* Skip over assignment statements preceding a command name. If we + don't find a command name at all, we can perform command name + completion. If we find a partial command name, we should perform + command name completion on it. */ + FREE (n); + n = find_cmd_name (s, &s1, &e1); + s = e1 + 1; + } + while (was_assignment = assignment (n, 0)); + s = s1; /* reset to index where name begins */ + + /* s == index of where command name begins (reset above) + e == end of current command, may be end of line + s1 = index of where command name begins + e1 == index of where command name ends + start == index of where word to be completed begins + end == index of where word to be completed ends + if (s == start) we are doing command word completion for sure + if (e1 == end) we are at the end of the command name and completing it */ + if (start == 0 && end == 0 && e != 0 && text[0] == '\0') /* beginning of non-empty line */ + foundcs = 0; + else if (start == end && start == s1 && e != 0 && e1 > end) /* beginning of command name, leading whitespace */ + foundcs = 0; + else if (e == 0 && e == s && text[0] == '\0' && have_progcomps) /* beginning of empty line */ + prog_complete_matches = programmable_completions ("_EmptycmD_", text, s, e, &foundcs); + else if (start == end && text[0] == '\0' && s1 > start && whitespace (rl_line_buffer[start])) + foundcs = 0; /* whitespace before command name */ + else if (e > s && was_assignment == 0 && e1 == end && rl_line_buffer[e] == 0 && whitespace (rl_line_buffer[e-1]) == 0) + { + /* not assignment statement, but still want to perform command + completion if we are composing command word. */ + foundcs = 0; + in_command_position = s == start && STREQ (n, text); /* XXX */ + } + else if (e > s && was_assignment == 0 && have_progcomps) + { + prog_complete_matches = programmable_completions (n, text, s, e, &foundcs); + /* command completion if programmable completion fails */ + in_command_position = s == start && STREQ (n, text); /* XXX */ + } + /* empty command name following command separator */ + else if (s >= e && n[0] == '\0' && text[0] == '\0' && start > 0 && + was_assignment == 0 && member (rl_line_buffer[start-1], COMMAND_SEPARATORS)) + { + foundcs = 0; + in_command_position = 1; + } + else if (s >= e && n[0] == '\0' && text[0] == '\0' && start > 0) + { + foundcs = 0; /* empty command name following assignments */ + in_command_position = was_assignment; + } + else if (s == start && e == end && STREQ (n, text) && start > 0) + { + foundcs = 0; /* partial command name following assignments */ + in_command_position = 1; + } + else + foundcs = 0; + FREE (n); + /* XXX - if we found a COMPSPEC for the command, just return whatever + the programmable completion code returns, and disable the default + filename completion that readline will do unless the COPT_DEFAULT + option has been set with the `-o default' option to complete or + compopt. */ + if (foundcs) + { + pcomp_set_readline_variables (foundcs, 1); + /* Turn what the programmable completion code returns into what + readline wants. I should have made compute_lcd_of_matches + external... */ + matches = rl_completion_matches (text, prog_complete_return); + if ((foundcs & COPT_DEFAULT) == 0) + rl_attempted_completion_over = 1; /* no default */ + if (matches || ((foundcs & COPT_BASHDEFAULT) == 0)) + return (matches); + } + } +#endif + + if (matches == 0) + { + dflags = 0; + if (in_command_position) + dflags |= DEFCOMP_CMDPOS; + matches = bash_default_completion (text, start, end, qc, dflags); + } + + return matches; +} + +char ** +bash_default_completion (text, start, end, qc, compflags) + const char *text; + int start, end, qc, compflags; +{ + char **matches, *t; + + matches = (char **)NULL; + + /* New posix-style command substitution or variable name? */ + if (!matches && *text == '$') + { + if (qc != '\'' && text[1] == '(') /* ) */ + matches = rl_completion_matches (text, command_subst_completion_function); + else + { + matches = rl_completion_matches (text, variable_completion_function); + if (matches && matches[0] && matches[1] == 0) + { + t = savestring (matches[0]); + bash_filename_stat_hook (&t); + /* doesn't use test_for_directory because that performs tilde + expansion */ + if (file_isdir (t)) + rl_completion_append_character = '/'; + free (t); + } + } + } + + /* If the word starts in `~', and there is no slash in the word, then + try completing this word as a username. */ + if (matches == 0 && *text == '~' && mbschr (text, '/') == 0) + matches = rl_completion_matches (text, rl_username_completion_function); + + /* Another one. Why not? If the word starts in '@', then look through + the world of known hostnames for completion first. */ + if (matches == 0 && perform_hostname_completion && *text == '@') + matches = rl_completion_matches (text, hostname_completion_function); + + /* And last, (but not least) if this word is in a command position, then + complete over possible command names, including aliases, functions, + and command names. */ + if (matches == 0 && (compflags & DEFCOMP_CMDPOS)) + { + /* If END == START and text[0] == 0, we are trying to complete an empty + command word. */ + if (no_empty_command_completion && end == start && text[0] == '\0') + { + matches = (char **)NULL; + rl_ignore_some_completions_function = bash_ignore_everything; + } + else + { +#define CMD_IS_DIR(x) (absolute_pathname(x) == 0 && absolute_program(x) == 0 && *(x) != '~' && test_for_directory (x)) + + dot_in_path = 0; + matches = rl_completion_matches (text, command_word_completion_function); + + /* If we are attempting command completion and nothing matches, we + do not want readline to perform filename completion for us. We + still want to be able to complete partial pathnames, so set the + completion ignore function to something which will remove + filenames and leave directories in the match list. */ + if (matches == (char **)NULL) + rl_ignore_some_completions_function = bash_ignore_filenames; + else if (matches[1] == 0 && CMD_IS_DIR(matches[0]) && dot_in_path == 0) + /* If we found a single match, without looking in the current + directory (because it's not in $PATH), but the found name is + also a command in the current directory, suppress appending any + terminating character, since it's ambiguous. */ + { + rl_completion_suppress_append = 1; + rl_filename_completion_desired = 0; + } + else if (matches[0] && matches[1] && STREQ (matches[0], matches[1]) && CMD_IS_DIR (matches[0])) + /* There are multiple instances of the same match (duplicate + completions haven't yet been removed). In this case, all of + the matches will be the same, and the duplicate removal code + will distill them all down to one. We turn on + rl_completion_suppress_append for the same reason as above. + Remember: we only care if there's eventually a single unique + completion. If there are multiple completions this won't + make a difference and the problem won't occur. */ + { + rl_completion_suppress_append = 1; + rl_filename_completion_desired = 0; + } + } + } + + /* This could be a globbing pattern, so try to expand it using pathname + expansion. */ + if (!matches && glob_pattern_p (text)) + { + matches = rl_completion_matches (text, glob_complete_word); + /* A glob expression that matches more than one filename is problematic. + If we match more than one filename, punt. */ + if (matches && matches[1] && rl_completion_type == TAB) + { + strvec_dispose (matches); + matches = (char **)0; + } + else if (matches && matches[1] && rl_completion_type == '!') + { + rl_completion_suppress_append = 1; + rl_filename_completion_desired = 0; + } + } + + return (matches); +} + +static int +bash_command_name_stat_hook (name) + char **name; +{ + char *cname, *result; + + /* If it's not something we're going to look up in $PATH, just call the + normal filename stat hook. */ + if (absolute_program (*name)) + return (bash_filename_stat_hook (name)); + + cname = *name; + /* XXX - we could do something here with converting aliases, builtins, + and functions into something that came out as executable, but we don't. */ + result = search_for_command (cname, 0); + if (result) + { + *name = result; + return 1; + } + return 0; +} + +static int +executable_completion (filename, searching_path) + const char *filename; + int searching_path; +{ + char *f; + int r; + + f = savestring (filename); + bash_directory_completion_hook (&f); + + r = searching_path ? executable_file (f) : executable_or_directory (f); + free (f); + return r; +} + +/* This is the function to call when the word to complete is in a position + where a command word can be found. It grovels $PATH, looking for commands + that match. It also scans aliases, function names, and the shell_builtin + table. */ +char * +command_word_completion_function (hint_text, state) + const char *hint_text; + int state; +{ + static char *hint = (char *)NULL; + static char *path = (char *)NULL; + static char *val = (char *)NULL; + static char *filename_hint = (char *)NULL; + static char *fnhint = (char *)NULL; + static char *dequoted_hint = (char *)NULL; + static char *directory_part = (char *)NULL; + static char **glob_matches = (char **)NULL; + static int path_index, hint_len, dequoted_len, istate, igncase; + static int mapping_over, local_index, searching_path, hint_is_dir; + static int old_glob_ignore_case, globpat; + static SHELL_VAR **varlist = (SHELL_VAR **)NULL; +#if defined (ALIAS) + static alias_t **alias_list = (alias_t **)NULL; +#endif /* ALIAS */ + char *temp, *cval; + + /* We have to map over the possibilities for command words. If we have + no state, then make one just for that purpose. */ + if (state == 0) + { + rl_filename_stat_hook = bash_command_name_stat_hook; + + if (dequoted_hint && dequoted_hint != hint) + free (dequoted_hint); + if (hint) + free (hint); + + mapping_over = searching_path = 0; + hint_is_dir = CMD_IS_DIR (hint_text); + val = (char *)NULL; + + temp = rl_variable_value ("completion-ignore-case"); + igncase = RL_BOOLEAN_VARIABLE_VALUE (temp); + + if (glob_matches) + { + free (glob_matches); + glob_matches = (char **)NULL; + } + + globpat = glob_pattern_p (hint_text); + + /* If this is an absolute program name, do not check it against + aliases, reserved words, functions or builtins. We must check + whether or not it is unique, and, if so, whether that filename + is executable. */ + if (globpat || absolute_program (hint_text)) + { + /* Perform tilde expansion on what's passed, so we don't end up + passing filenames with tildes directly to stat(). */ + if (*hint_text == '~') + { + hint = bash_tilde_expand (hint_text, 0); + directory_part = savestring (hint_text); + temp = strchr (directory_part, '/'); + if (temp) + *temp = 0; + else + { + free (directory_part); + directory_part = (char *)NULL; + } + } + else + hint = savestring (hint_text); + + dequoted_hint = hint; + /* If readline's completer found a quote character somewhere, but + didn't set the quote character, there must have been a quote + character embedded in the filename. It can't be at the start of + the filename, so we need to dequote the filename before we look + in the file system for it. */ + if (rl_completion_found_quote && rl_completion_quote_character == 0) + { + dequoted_hint = bash_dequote_filename (hint, 0); + free (hint); + hint = dequoted_hint; + } + dequoted_len = hint_len = strlen (hint); + + if (filename_hint) + free (filename_hint); + + fnhint = filename_hint = savestring (hint); + + istate = 0; + + if (globpat) + { + mapping_over = 5; + goto globword; + } + else + { + if (dircomplete_expand && path_dot_or_dotdot (filename_hint)) + { + dircomplete_expand = 0; + set_directory_hook (); + dircomplete_expand = 1; + } + mapping_over = 4; + goto inner; + } + } + + dequoted_hint = hint = savestring (hint_text); + dequoted_len = hint_len = strlen (hint); + + if (rl_completion_found_quote && rl_completion_quote_character == 0) + { + dequoted_hint = bash_dequote_filename (hint, 0); + dequoted_len = strlen (dequoted_hint); + } + + path = get_string_value ("PATH"); + path_index = dot_in_path = 0; + + /* Initialize the variables for each type of command word. */ + local_index = 0; + + if (varlist) + free (varlist); + + varlist = all_visible_functions (); + +#if defined (ALIAS) + if (alias_list) + free (alias_list); + + alias_list = all_aliases (); +#endif /* ALIAS */ + } + + /* mapping_over says what we are currently hacking. Note that every case + in this list must fall through when there are no more possibilities. */ + + switch (mapping_over) + { + case 0: /* Aliases come first. */ +#if defined (ALIAS) + while (alias_list && alias_list[local_index]) + { + register char *alias; + + alias = alias_list[local_index++]->name; + + if (STREQN (alias, hint, hint_len)) + return (savestring (alias)); + } +#endif /* ALIAS */ + local_index = 0; + mapping_over++; + + case 1: /* Then shell reserved words. */ + { + while (word_token_alist[local_index].word) + { + register char *reserved_word; + + reserved_word = word_token_alist[local_index++].word; + + if (STREQN (reserved_word, hint, hint_len)) + return (savestring (reserved_word)); + } + local_index = 0; + mapping_over++; + } + + case 2: /* Then function names. */ + while (varlist && varlist[local_index]) + { + register char *varname; + + varname = varlist[local_index++]->name; + + if (STREQN (varname, hint, hint_len)) + return (savestring (varname)); + } + local_index = 0; + mapping_over++; + + case 3: /* Then shell builtins. */ + for (; local_index < num_shell_builtins; local_index++) + { + /* Ignore it if it doesn't have a function pointer or if it + is not currently enabled. */ + if (!shell_builtins[local_index].function || + (shell_builtins[local_index].flags & BUILTIN_ENABLED) == 0) + continue; + + if (STREQN (shell_builtins[local_index].name, hint, hint_len)) + { + int i = local_index++; + + return (savestring (shell_builtins[i].name)); + } + } + local_index = 0; + mapping_over++; + } + +globword: + /* Limited support for completing command words with globbing chars. Only + a single match (multiple matches that end up reducing the number of + characters in the common prefix are bad) will ever be returned on + regular completion. */ + if (globpat) + { + if (state == 0) + { + glob_ignore_case = igncase; + glob_matches = shell_glob_filename (hint); + glob_ignore_case = old_glob_ignore_case; + + if (GLOB_FAILED (glob_matches) || glob_matches == 0) + { + glob_matches = (char **)NULL; + return ((char *)NULL); + } + + local_index = 0; + + if (glob_matches[1] && rl_completion_type == TAB) /* multiple matches are bad */ + return ((char *)NULL); + } + + while (val = glob_matches[local_index++]) + { + if (executable_or_directory (val)) + { + if (*hint_text == '~' && directory_part) + { + temp = maybe_restore_tilde (val, directory_part); + free (val); + val = temp; + } + return (val); + } + free (val); + } + + glob_ignore_case = old_glob_ignore_case; + return ((char *)NULL); + } + + /* If the text passed is a directory in the current directory, return it + as a possible match. Executables in directories in the current + directory can be specified using relative pathnames and successfully + executed even when `.' is not in $PATH. */ + if (hint_is_dir) + { + hint_is_dir = 0; /* only return the hint text once */ + return (savestring (hint_text)); + } + + /* Repeatedly call filename_completion_function while we have + members of PATH left. Question: should we stat each file? + Answer: we call executable_file () on each file. */ + outer: + + istate = (val != (char *)NULL); + + if (istate == 0) + { + char *current_path; + + /* Get the next directory from the path. If there is none, then we + are all done. */ + if (path == 0 || path[path_index] == 0 || + (current_path = extract_colon_unit (path, &path_index)) == 0) + return ((char *)NULL); + + searching_path = 1; + if (*current_path == 0) + { + free (current_path); + current_path = savestring ("."); + } + + if (*current_path == '~') + { + char *t; + + t = bash_tilde_expand (current_path, 0); + free (current_path); + current_path = t; + } + + if (current_path[0] == '.' && current_path[1] == '\0') + dot_in_path = 1; + + if (fnhint && fnhint != filename_hint) + free (fnhint); + if (filename_hint) + free (filename_hint); + + filename_hint = sh_makepath (current_path, hint, 0); + /* Need a quoted version (though it doesn't matter much in most + cases) because rl_filename_completion_function dequotes the + filename it gets, assuming that it's been quoted as part of + the input line buffer. */ + if (strpbrk (filename_hint, "\"'\\")) + fnhint = sh_backslash_quote (filename_hint, filename_bstab, 0); + else + fnhint = filename_hint; + free (current_path); /* XXX */ + } + + inner: + val = rl_filename_completion_function (fnhint, istate); + if (mapping_over == 4 && dircomplete_expand) + set_directory_hook (); + + istate = 1; + + if (val == 0) + { + /* If the hint text is an absolute program, then don't bother + searching through PATH. */ + if (absolute_program (hint)) + return ((char *)NULL); + + goto outer; + } + else + { + int match, freetemp; + + if (absolute_program (hint)) + { + if (igncase == 0) + match = strncmp (val, hint, hint_len) == 0; + else + match = strncasecmp (val, hint, hint_len) == 0; + + /* If we performed tilde expansion, restore the original + filename. */ + if (*hint_text == '~') + temp = maybe_restore_tilde (val, directory_part); + else + temp = savestring (val); + freetemp = 1; + } + else + { + temp = strrchr (val, '/'); + + if (temp) + { + temp++; + if (igncase == 0) + freetemp = match = strncmp (temp, hint, hint_len) == 0; + else + freetemp = match = strncasecmp (temp, hint, hint_len) == 0; + if (match) + temp = savestring (temp); + } + else + freetemp = match = 0; + } + + /* If we have found a match, and it is an executable file, return it. + We don't return directory names when searching $PATH, since the + bash execution code won't find executables in directories which + appear in directories in $PATH when they're specified using + relative pathnames. */ +#if 0 + /* If we're not searching $PATH and we have a relative pathname, we + need to re-canonicalize it before testing whether or not it's an + executable or a directory so the shell treats .. relative to $PWD + according to the physical/logical option. The shell already + canonicalizes the directory name in order to tell readline where + to look, so not doing it here will be inconsistent. */ + /* XXX -- currently not used -- will introduce more inconsistency, + since shell does not canonicalize ../foo before passing it to + shell_execve(). */ + if (match && searching_path == 0 && *val == '.') + { + char *t, *t1; + + t = get_working_directory ("command-word-completion"); + t1 = make_absolute (val, t); + free (t); + cval = sh_canonpath (t1, PATH_CHECKDOTDOT|PATH_CHECKEXISTS); + } + else +#endif + cval = val; + + if (match && executable_completion ((searching_path ? val : cval), searching_path)) + { + if (cval != val) + free (cval); + free (val); + val = ""; /* So it won't be NULL. */ + return (temp); + } + else + { + if (freetemp) + free (temp); + if (cval != val) + free (cval); + free (val); + goto inner; + } + } +} + +/* Completion inside an unterminated command substitution. */ +static char * +command_subst_completion_function (text, state) + const char *text; + int state; +{ + static char **matches = (char **)NULL; + static const char *orig_start; + static char *filename_text = (char *)NULL; + static int cmd_index, start_len; + char *value; + + if (state == 0) + { + if (filename_text) + free (filename_text); + orig_start = text; + if (*text == '`') + text++; + else if (*text == '$' && text[1] == '(') /* ) */ + text += 2; + /* If the text was quoted, suppress any quote character that the + readline completion code would insert. */ + rl_completion_suppress_quote = 1; + start_len = text - orig_start; + filename_text = savestring (text); + if (matches) + free (matches); + + /* + * At this point we can entertain the idea of re-parsing + * `filename_text' into a (possibly incomplete) command name and + * arguments, and doing completion based on that. This is + * currently very rudimentary, but it is a small improvement. + */ + for (value = filename_text + strlen (filename_text) - 1; value > filename_text; value--) + if (whitespace (*value) || member (*value, COMMAND_SEPARATORS)) + break; + if (value <= filename_text) + matches = rl_completion_matches (filename_text, command_word_completion_function); + else + { + value++; + start_len += value - filename_text; + if (whitespace (value[-1])) + matches = rl_completion_matches (value, rl_filename_completion_function); + else + matches = rl_completion_matches (value, command_word_completion_function); + } + + /* If there is more than one match, rl_completion_matches has already + put the lcd in matches[0]. Skip over it. */ + cmd_index = matches && matches[0] && matches[1]; + + /* If there's a single match and it's a directory, set the append char + to the expected `/'. Otherwise, don't append anything. */ + if (matches && matches[0] && matches[1] == 0 && test_for_directory (matches[0])) + rl_completion_append_character = '/'; + else + rl_completion_suppress_append = 1; + } + + if (matches == 0 || matches[cmd_index] == 0) + { + rl_filename_quoting_desired = 0; /* disable quoting */ + return ((char *)NULL); + } + else + { + value = (char *)xmalloc (1 + start_len + strlen (matches[cmd_index])); + + if (start_len == 1) + value[0] = *orig_start; + else + strncpy (value, orig_start, start_len); + + strcpy (value + start_len, matches[cmd_index]); + + cmd_index++; + return (value); + } +} + +/* Okay, now we write the entry_function for variable completion. */ +static char * +variable_completion_function (text, state) + const char *text; + int state; +{ + static char **varlist = (char **)NULL; + static int varlist_index; + static char *varname = (char *)NULL; + static int namelen; + static int first_char, first_char_loc; + + if (!state) + { + if (varname) + free (varname); + + first_char_loc = 0; + first_char = text[0]; + + if (first_char == '$') + first_char_loc++; + + if (text[first_char_loc] == '{') + first_char_loc++; + + varname = savestring (text + first_char_loc); + + namelen = strlen (varname); + if (varlist) + strvec_dispose (varlist); + + varlist = all_variables_matching_prefix (varname); + varlist_index = 0; + } + + if (!varlist || !varlist[varlist_index]) + { + return ((char *)NULL); + } + else + { + char *value; + + value = (char *)xmalloc (4 + strlen (varlist[varlist_index])); + + if (first_char_loc) + { + value[0] = first_char; + if (first_char_loc == 2) + value[1] = '{'; + } + + strcpy (value + first_char_loc, varlist[varlist_index]); + if (first_char_loc == 2) + strcat (value, "}"); + + varlist_index++; + return (value); + } +} + +/* How about a completion function for hostnames? */ +static char * +hostname_completion_function (text, state) + const char *text; + int state; +{ + static char **list = (char **)NULL; + static int list_index = 0; + static int first_char, first_char_loc; + + /* If we don't have any state, make some. */ + if (state == 0) + { + FREE (list); + + list = (char **)NULL; + + first_char_loc = 0; + first_char = *text; + + if (first_char == '@') + first_char_loc++; + + list = hostnames_matching ((char *)text+first_char_loc); + list_index = 0; + } + + if (list && list[list_index]) + { + char *t; + + t = (char *)xmalloc (2 + strlen (list[list_index])); + *t = first_char; + strcpy (t + first_char_loc, list[list_index]); + list_index++; + return (t); + } + + return ((char *)NULL); +} + +/* + * A completion function for service names from /etc/services (or wherever). + */ +char * +bash_servicename_completion_function (text, state) + const char *text; + int state; +{ +#if defined (__WIN32__) || defined (__OPENNT) || !defined (HAVE_GETSERVENT) + return ((char *)NULL); +#else + static char *sname = (char *)NULL; + static struct servent *srvent; + static int snamelen, firstc; + char *value; + char **alist, *aentry; + int afound; + + if (state == 0) + { + FREE (sname); + firstc = *text; + + sname = savestring (text); + snamelen = strlen (sname); + setservent (0); + } + + while (srvent = getservent ()) + { + afound = 0; + if (snamelen == 0 || (STREQN (sname, srvent->s_name, snamelen))) + break; + /* Not primary, check aliases */ + for (alist = srvent->s_aliases; *alist; alist++) + { + aentry = *alist; + if (STREQN (sname, aentry, snamelen)) + { + afound = 1; + break; + } + } + + if (afound) + break; + } + + if (srvent == 0) + { + endservent (); + return ((char *)NULL); + } + + value = afound ? savestring (aentry) : savestring (srvent->s_name); + return value; +#endif +} + +/* + * A completion function for group names from /etc/group (or wherever). + */ +char * +bash_groupname_completion_function (text, state) + const char *text; + int state; +{ +#if defined (__WIN32__) || defined (__OPENNT) || !defined (HAVE_GRP_H) + return ((char *)NULL); +#else + static char *gname = (char *)NULL; + static struct group *grent; + static int gnamelen; + char *value; + + if (state == 0) + { + FREE (gname); + gname = savestring (text); + gnamelen = strlen (gname); + + setgrent (); + } + + while (grent = getgrent ()) + { + if (gnamelen == 0 || (STREQN (gname, grent->gr_name, gnamelen))) + break; + } + + if (grent == 0) + { + endgrent (); + return ((char *)NULL); + } + + value = savestring (grent->gr_name); + return (value); +#endif +} + +/* Functions to perform history and alias expansions on the current line. */ + +#if defined (BANG_HISTORY) +/* Perform history expansion on the current line. If no history expansion + is done, pre_process_line() returns what it was passed, so we need to + allocate a new line here. */ +static char * +history_expand_line_internal (line) + char *line; +{ + char *new_line; + int old_verify; + + old_verify = hist_verify; + hist_verify = 0; + new_line = pre_process_line (line, 0, 0); + hist_verify = old_verify; + + return (new_line == line) ? savestring (line) : new_line; +} +#endif + +/* There was an error in expansion. Let the preprocessor print + the error here. */ +static void +cleanup_expansion_error () +{ + char *to_free; +#if defined (BANG_HISTORY) + int old_verify; + + old_verify = hist_verify; + hist_verify = 0; +#endif + + fprintf (rl_outstream, "\r\n"); + to_free = pre_process_line (rl_line_buffer, 1, 0); +#if defined (BANG_HISTORY) + hist_verify = old_verify; +#endif + if (to_free != rl_line_buffer) + FREE (to_free); + putc ('\r', rl_outstream); + rl_forced_update_display (); +} + +/* If NEW_LINE differs from what is in the readline line buffer, add an + undo record to get from the readline line buffer contents to the new + line and make NEW_LINE the current readline line. */ +static void +maybe_make_readline_line (new_line) + char *new_line; +{ + if (strcmp (new_line, rl_line_buffer) != 0) + { + rl_point = rl_end; + + rl_add_undo (UNDO_BEGIN, 0, 0, 0); + rl_delete_text (0, rl_point); + rl_point = rl_end = rl_mark = 0; + rl_insert_text (new_line); + rl_add_undo (UNDO_END, 0, 0, 0); + } +} + +/* Make NEW_LINE be the current readline line. This frees NEW_LINE. */ +static void +set_up_new_line (new_line) + char *new_line; +{ + int old_point, at_end; + + old_point = rl_point; + at_end = rl_point == rl_end; + + /* If the line was history and alias expanded, then make that + be one thing to undo. */ + maybe_make_readline_line (new_line); + free (new_line); + + /* Place rl_point where we think it should go. */ + if (at_end) + rl_point = rl_end; + else if (old_point < rl_end) + { + rl_point = old_point; + if (!whitespace (rl_line_buffer[rl_point])) + rl_forward_word (1, 0); + } +} + +#if defined (ALIAS) +/* Expand aliases in the current readline line. */ +static int +alias_expand_line (count, ignore) + int count, ignore; +{ + char *new_line; + + new_line = alias_expand (rl_line_buffer); + + if (new_line) + { + set_up_new_line (new_line); + return (0); + } + else + { + cleanup_expansion_error (); + return (1); + } +} +#endif + +#if defined (BANG_HISTORY) +/* History expand the line. */ +static int +history_expand_line (count, ignore) + int count, ignore; +{ + char *new_line; + + new_line = history_expand_line_internal (rl_line_buffer); + + if (new_line) + { + set_up_new_line (new_line); + return (0); + } + else + { + cleanup_expansion_error (); + return (1); + } +} + +/* Expand history substitutions in the current line and then insert a + space (hopefully close to where we were before). */ +static int +tcsh_magic_space (count, ignore) + int count, ignore; +{ + int dist_from_end, old_point; + + old_point = rl_point; + dist_from_end = rl_end - rl_point; + if (history_expand_line (count, ignore) == 0) + { + /* Try a simple heuristic from Stephen Gildea . + This works if all expansions were before rl_point or if no expansions + were performed. */ + rl_point = (old_point == 0) ? old_point : rl_end - dist_from_end; + rl_insert (1, ' '); + return (0); + } + else + return (1); +} +#endif /* BANG_HISTORY */ + +/* History and alias expand the line. */ +static int +history_and_alias_expand_line (count, ignore) + int count, ignore; +{ + char *new_line; + + new_line = 0; +#if defined (BANG_HISTORY) + new_line = history_expand_line_internal (rl_line_buffer); +#endif + +#if defined (ALIAS) + if (new_line) + { + char *alias_line; + + alias_line = alias_expand (new_line); + free (new_line); + new_line = alias_line; + } +#endif /* ALIAS */ + + if (new_line) + { + set_up_new_line (new_line); + return (0); + } + else + { + cleanup_expansion_error (); + return (1); + } +} + +/* History and alias expand the line, then perform the shell word + expansions by calling expand_string. This can't use set_up_new_line() + because we want the variable expansions as a separate undo'able + set of operations. */ +static int +shell_expand_line (count, ignore) + int count, ignore; +{ + char *new_line; + WORD_LIST *expanded_string; + + new_line = 0; +#if defined (BANG_HISTORY) + new_line = history_expand_line_internal (rl_line_buffer); +#endif + +#if defined (ALIAS) + if (new_line) + { + char *alias_line; + + alias_line = alias_expand (new_line); + free (new_line); + new_line = alias_line; + } +#endif /* ALIAS */ + + if (new_line) + { + int old_point = rl_point; + int at_end = rl_point == rl_end; + + /* If the line was history and alias expanded, then make that + be one thing to undo. */ + maybe_make_readline_line (new_line); + free (new_line); + + /* If there is variable expansion to perform, do that as a separate + operation to be undone. */ + new_line = savestring (rl_line_buffer); + expanded_string = expand_string (new_line, 0); + FREE (new_line); + if (expanded_string == 0) + { + new_line = (char *)xmalloc (1); + new_line[0] = '\0'; + } + else + { + new_line = string_list (expanded_string); + dispose_words (expanded_string); + } + + maybe_make_readline_line (new_line); + free (new_line); + + /* Place rl_point where we think it should go. */ + if (at_end) + rl_point = rl_end; + else if (old_point < rl_end) + { + rl_point = old_point; + if (!whitespace (rl_line_buffer[rl_point])) + rl_forward_word (1, 0); + } + return 0; + } + else + { + cleanup_expansion_error (); + return 1; + } +} + +/* If FIGNORE is set, then don't match files with the given suffixes when + completing filenames. If only one of the possibilities has an acceptable + suffix, delete the others, else just return and let the completer + signal an error. It is called by the completer when real + completions are done on filenames by the completer's internal + function, not for completion lists (M-?) and not on "other" + completion types, such as hostnames or commands. */ + +static struct ignorevar fignore = +{ + "FIGNORE", + (struct ign *)0, + 0, + (char *)0, + (sh_iv_item_func_t *) 0, +}; + +static void +_ignore_completion_names (names, name_func) + char **names; + sh_ignore_func_t *name_func; +{ + char **newnames; + int idx, nidx; + char **oldnames; + int oidx; + + /* If there is only one completion, see if it is acceptable. If it is + not, free it up. In any case, short-circuit and return. This is a + special case because names[0] is not the prefix of the list of names + if there is only one completion; it is the completion itself. */ + if (names[1] == (char *)0) + { + if (force_fignore) + if ((*name_func) (names[0]) == 0) + { + free (names[0]); + names[0] = (char *)NULL; + } + + return; + } + + /* Allocate space for array to hold list of pointers to matching + filenames. The pointers are copied back to NAMES when done. */ + for (nidx = 1; names[nidx]; nidx++) + ; + newnames = strvec_create (nidx + 1); + + if (force_fignore == 0) + { + oldnames = strvec_create (nidx - 1); + oidx = 0; + } + + newnames[0] = names[0]; + for (idx = nidx = 1; names[idx]; idx++) + { + if ((*name_func) (names[idx])) + newnames[nidx++] = names[idx]; + else if (force_fignore == 0) + oldnames[oidx++] = names[idx]; + else + free (names[idx]); + } + + newnames[nidx] = (char *)NULL; + + /* If none are acceptable then let the completer handle it. */ + if (nidx == 1) + { + if (force_fignore) + { + free (names[0]); + names[0] = (char *)NULL; + } + else + free (oldnames); + + free (newnames); + return; + } + + if (force_fignore == 0) + { + while (oidx) + free (oldnames[--oidx]); + free (oldnames); + } + + /* If only one is acceptable, copy it to names[0] and return. */ + if (nidx == 2) + { + free (names[0]); + names[0] = newnames[1]; + names[1] = (char *)NULL; + free (newnames); + return; + } + + /* Copy the acceptable names back to NAMES, set the new array end, + and return. */ + for (nidx = 1; newnames[nidx]; nidx++) + names[nidx] = newnames[nidx]; + names[nidx] = (char *)NULL; + free (newnames); +} + +static int +name_is_acceptable (name) + const char *name; +{ + struct ign *p; + int nlen; + + for (nlen = strlen (name), p = fignore.ignores; p->val; p++) + { + if (nlen > p->len && p->len > 0 && STREQ (p->val, &name[nlen - p->len])) + return (0); + } + + return (1); +} + +#if 0 +static int +ignore_dot_names (name) + char *name; +{ + return (name[0] != '.'); +} +#endif + +static int +filename_completion_ignore (names) + char **names; +{ +#if 0 + if (glob_dot_filenames == 0) + _ignore_completion_names (names, ignore_dot_names); +#endif + + setup_ignore_patterns (&fignore); + + if (fignore.num_ignores == 0) + return 0; + + _ignore_completion_names (names, name_is_acceptable); + + return 0; +} + +/* Return 1 if NAME is a directory. NAME undergoes tilde expansion. */ +static int +test_for_directory (name) + const char *name; +{ + char *fn; + int r; + + fn = bash_tilde_expand (name, 0); + r = file_isdir (fn); + free (fn); + + return (r); +} + +/* Remove files from NAMES, leaving directories. */ +static int +bash_ignore_filenames (names) + char **names; +{ + _ignore_completion_names (names, test_for_directory); + return 0; +} + +static int +return_zero (name) + const char *name; +{ + return 0; +} + +static int +bash_ignore_everything (names) + char **names; +{ + _ignore_completion_names (names, return_zero); + return 0; +} + +/* Replace a tilde-prefix in VAL with a `~', assuming the user typed it. VAL + is an expanded filename. DIRECTORY_PART is the tilde-prefix portion + of the un-tilde-expanded version of VAL (what the user typed). */ +static char * +restore_tilde (val, directory_part) + char *val, *directory_part; +{ + int l, vl, dl2, xl; + char *dh2, *expdir, *ret; + + vl = strlen (val); + + /* We need to duplicate the expansions readline performs on the directory + portion before passing it to our completion function. */ + dh2 = directory_part ? bash_dequote_filename (directory_part, 0) : 0; + bash_directory_expansion (&dh2); + dl2 = strlen (dh2); + + expdir = bash_tilde_expand (directory_part, 0); + xl = strlen (expdir); + free (expdir); + + /* + dh2 = unexpanded but dequoted tilde-prefix + dl2 = length of tilde-prefix + expdir = tilde-expanded tilde-prefix + xl = length of expanded tilde-prefix + l = length of remainder after tilde-prefix + */ + l = (vl - xl) + 1; + + ret = (char *)xmalloc (dl2 + 2 + l); + strcpy (ret, dh2); + strcpy (ret + dl2, val + xl); + + free (dh2); + return (ret); +} + +static char * +maybe_restore_tilde (val, directory_part) + char *val, *directory_part; +{ + rl_icppfunc_t *save; + char *ret; + + save = (dircomplete_expand == 0) ? save_directory_hook () : (rl_icppfunc_t *)0; + ret = restore_tilde (val, directory_part); + if (save) + restore_directory_hook (save); + return ret; +} + +/* Simulate the expansions that will be performed by + rl_filename_completion_function. This must be called with the address of + a pointer to malloc'd memory. */ +static void +bash_directory_expansion (dirname) + char **dirname; +{ + char *d, *nd; + + d = savestring (*dirname); + + if ((rl_directory_rewrite_hook) && (*rl_directory_rewrite_hook) (&d)) + { + free (*dirname); + *dirname = d; + } + else if (rl_directory_completion_hook && (*rl_directory_completion_hook) (&d)) + { + free (*dirname); + *dirname = d; + } + else if (rl_completion_found_quote) + { + nd = bash_dequote_filename (d, rl_completion_quote_character); + free (*dirname); + free (d); + *dirname = nd; + } +} + +/* If necessary, rewrite directory entry */ +static char * +bash_filename_rewrite_hook (fname, fnlen) + char *fname; + int fnlen; +{ + char *conv; + + conv = fnx_fromfs (fname, fnlen); + if (conv != fname) + conv = savestring (conv); + return conv; +} + +/* Functions to save and restore the appropriate directory hook */ +/* This is not static so the shopt code can call it */ +void +set_directory_hook () +{ + if (dircomplete_expand) + { + rl_directory_completion_hook = bash_directory_completion_hook; + rl_directory_rewrite_hook = (rl_icppfunc_t *)0; + } + else + { + rl_directory_rewrite_hook = bash_directory_completion_hook; + rl_directory_completion_hook = (rl_icppfunc_t *)0; + } +} + +static rl_icppfunc_t * +save_directory_hook () +{ + rl_icppfunc_t *ret; + + if (dircomplete_expand) + { + ret = rl_directory_completion_hook; + rl_directory_completion_hook = (rl_icppfunc_t *)NULL; + } + else + { + ret = rl_directory_rewrite_hook; + rl_directory_rewrite_hook = (rl_icppfunc_t *)NULL; + } + + return ret; +} + +static void +restore_directory_hook (hookf) + rl_icppfunc_t *hookf; +{ + if (dircomplete_expand) + rl_directory_completion_hook = hookf; + else + rl_directory_rewrite_hook = hookf; +} + +/* Expand a filename before the readline completion code passes it to stat(2). + The filename will already have had tilde expansion performed. */ +static int +bash_filename_stat_hook (dirname) + char **dirname; +{ + char *local_dirname, *new_dirname, *t; + int should_expand_dirname, return_value; + WORD_LIST *wl; + struct stat sb; + + local_dirname = *dirname; + should_expand_dirname = return_value = 0; + if (t = mbschr (local_dirname, '$')) + should_expand_dirname = '$'; + else if (t = mbschr (local_dirname, '`')) /* XXX */ + should_expand_dirname = '`'; + +#if defined (HAVE_LSTAT) + if (should_expand_dirname && lstat (local_dirname, &sb) == 0) +#else + if (should_expand_dirname && stat (local_dirname, &sb) == 0) +#endif + should_expand_dirname = 0; + + if (should_expand_dirname) + { + new_dirname = savestring (local_dirname); + wl = expand_prompt_string (new_dirname, 0, W_NOCOMSUB); /* does the right thing */ + if (wl) + { + free (new_dirname); + new_dirname = string_list (wl); + /* Tell the completer we actually expanded something and change + *dirname only if we expanded to something non-null -- stat + behaves unpredictably when passed null or empty strings */ + if (new_dirname && *new_dirname) + { + free (local_dirname); /* XXX */ + local_dirname = *dirname = new_dirname; + return_value = STREQ (local_dirname, *dirname) == 0; + } + else + free (new_dirname); + dispose_words (wl); + } + else + free (new_dirname); + } + + /* This is very similar to the code in bash_directory_completion_hook below, + but without spelling correction and not worrying about whether or not + we change relative pathnames. */ + if (no_symbolic_links == 0 && (local_dirname[0] != '.' || local_dirname[1])) + { + char *temp1, *temp2; + + t = get_working_directory ("symlink-hook"); + temp1 = make_absolute (local_dirname, t); + free (t); + temp2 = sh_canonpath (temp1, PATH_CHECKDOTDOT|PATH_CHECKEXISTS); + + /* If we can't canonicalize, bail. */ + if (temp2 == 0) + { + free (temp1); + return return_value; + } + + free (local_dirname); + *dirname = temp2; + free (temp1); + } + + return (return_value); +} + +/* Handle symbolic link references and other directory name + expansions while hacking completion. This should return 1 if it modifies + the DIRNAME argument, 0 otherwise. It should make sure not to modify + DIRNAME if it returns 0. */ +static int +bash_directory_completion_hook (dirname) + char **dirname; +{ + char *local_dirname, *new_dirname, *t; + int return_value, should_expand_dirname, nextch, closer; + WORD_LIST *wl; + struct stat sb; + + return_value = should_expand_dirname = nextch = closer = 0; + local_dirname = *dirname; + + if (t = mbschr (local_dirname, '$')) + { + should_expand_dirname = '$'; + nextch = t[1]; + /* Deliberately does not handle the deprecated $[...] arithmetic + expansion syntax */ + if (nextch == '(') + closer = ')'; + else if (nextch == '{') + closer = '}'; + else + nextch = 0; + } + else if (local_dirname[0] == '~') + should_expand_dirname = '~'; + else + { + t = mbschr (local_dirname, '`'); + if (t && unclosed_pair (local_dirname, strlen (local_dirname), "`") == 0) + should_expand_dirname = '`'; + } + +#if defined (HAVE_LSTAT) + if (should_expand_dirname && lstat (local_dirname, &sb) == 0) +#else + if (should_expand_dirname && stat (local_dirname, &sb) == 0) +#endif + should_expand_dirname = 0; + + if (should_expand_dirname) + { + new_dirname = savestring (local_dirname); + wl = expand_prompt_string (new_dirname, 0, W_NOCOMSUB); /* does the right thing */ + if (wl) + { + *dirname = string_list (wl); + /* Tell the completer to replace the directory name only if we + actually expanded something. */ + return_value = STREQ (local_dirname, *dirname) == 0; + free (local_dirname); + free (new_dirname); + dispose_words (wl); + local_dirname = *dirname; + /* XXX - change rl_filename_quote_characters here based on + should_expand_dirname/nextch/closer. This is the only place + custom_filename_quote_characters is modified. */ + if (rl_filename_quote_characters && *rl_filename_quote_characters) + { + int i, j, c; + i = strlen (default_filename_quote_characters); + custom_filename_quote_characters = xrealloc (custom_filename_quote_characters, i+1); + for (i = j = 0; c = default_filename_quote_characters[i]; i++) + { + if (c == should_expand_dirname || c == nextch || c == closer) + continue; + custom_filename_quote_characters[j++] = c; + } + custom_filename_quote_characters[j] = '\0'; + rl_filename_quote_characters = custom_filename_quote_characters; + set_filename_bstab (rl_filename_quote_characters); + } + } + else + { + free (new_dirname); + free (local_dirname); + *dirname = (char *)xmalloc (1); + **dirname = '\0'; + return 1; + } + } + else + { + /* Dequote the filename even if we don't expand it. */ + new_dirname = bash_dequote_filename (local_dirname, rl_completion_quote_character); + return_value = STREQ (local_dirname, new_dirname) == 0; + free (local_dirname); + local_dirname = *dirname = new_dirname; + } + + /* no_symbolic_links == 0 -> use (default) logical view of the file system. + local_dirname[0] == '.' && local_dirname[1] == '/' means files in the + current directory (./). + local_dirname[0] == '.' && local_dirname[1] == 0 means relative pathnames + in the current directory (e.g., lib/sh). + XXX - should we do spelling correction on these? */ + + /* This is test as it was in bash-4.2: skip relative pathnames in current + directory. Change test to + (local_dirname[0] != '.' || (local_dirname[1] && local_dirname[1] != '/')) + if we want to skip paths beginning with ./ also. */ + if (no_symbolic_links == 0 && (local_dirname[0] != '.' || local_dirname[1])) + { + char *temp1, *temp2; + int len1, len2; + + /* If we have a relative path + (local_dirname[0] != '/' && local_dirname[0] != '.') + that is canonical after appending it to the current directory, then + temp1 = temp2+'/' + That is, + strcmp (temp1, temp2) == 0 + after adding a slash to temp2 below. It should be safe to not + change those. + */ + t = get_working_directory ("symlink-hook"); + temp1 = make_absolute (local_dirname, t); + free (t); + temp2 = sh_canonpath (temp1, PATH_CHECKDOTDOT|PATH_CHECKEXISTS); + + /* Try spelling correction if initial canonicalization fails. Make + sure we are set to replace the directory name with the results so + subsequent directory checks don't fail. */ + if (temp2 == 0 && dircomplete_spelling && dircomplete_expand) + { + temp2 = dirspell (temp1); + if (temp2) + { + free (temp1); + temp1 = temp2; + temp2 = sh_canonpath (temp1, PATH_CHECKDOTDOT|PATH_CHECKEXISTS); + return_value |= temp2 != 0; + } + } + /* If we can't canonicalize, bail. */ + if (temp2 == 0) + { + free (temp1); + return return_value; + } + len1 = strlen (temp1); + if (temp1[len1 - 1] == '/') + { + len2 = strlen (temp2); + if (len2 > 2) /* don't append `/' to `/' or `//' */ + { + temp2 = (char *)xrealloc (temp2, len2 + 2); + temp2[len2] = '/'; + temp2[len2 + 1] = '\0'; + } + } + + /* dircomplete_expand_relpath == 0 means we want to leave relative + pathnames that are unchanged by canonicalization alone. + *local_dirname != '/' && *local_dirname != '.' == relative pathname + (consistent with general.c:absolute_pathname()) + temp1 == temp2 (after appending a slash to temp2) means the pathname + is not changed by canonicalization as described above. */ + if (dircomplete_expand_relpath || ((local_dirname[0] != '/' && local_dirname[0] != '.') && STREQ (temp1, temp2) == 0)) + return_value |= STREQ (local_dirname, temp2) == 0; + free (local_dirname); + *dirname = temp2; + free (temp1); + } + + return (return_value); +} + +static char **history_completion_array = (char **)NULL; +static int harry_size; +static int harry_len; + +static void +build_history_completion_array () +{ + register int i, j; + HIST_ENTRY **hlist; + char **tokens; + + /* First, clear out the current dynamic history completion list. */ + if (harry_size) + { + strvec_dispose (history_completion_array); + history_completion_array = (char **)NULL; + harry_size = 0; + harry_len = 0; + } + + /* Next, grovel each line of history, making each shell-sized token + a separate entry in the history_completion_array. */ + hlist = history_list (); + + if (hlist) + { + for (i = 0; hlist[i]; i++) + ; + for ( --i; i >= 0; i--) + { + /* Separate each token, and place into an array. */ + tokens = history_tokenize (hlist[i]->line); + + for (j = 0; tokens && tokens[j]; j++) + { + if (harry_len + 2 > harry_size) + history_completion_array = strvec_resize (history_completion_array, harry_size += 10); + + history_completion_array[harry_len++] = tokens[j]; + history_completion_array[harry_len] = (char *)NULL; + } + free (tokens); + } + + /* Sort the complete list of tokens. */ + if (dabbrev_expand_active == 0) + qsort (history_completion_array, harry_len, sizeof (char *), (QSFUNC *)strvec_strcmp); + } +} + +static char * +history_completion_generator (hint_text, state) + const char *hint_text; + int state; +{ + static int local_index, len; + static const char *text; + + /* If this is the first call to the generator, then initialize the + list of strings to complete over. */ + if (state == 0) + { + if (dabbrev_expand_active) /* This is kind of messy */ + rl_completion_suppress_append = 1; + local_index = 0; + build_history_completion_array (); + text = hint_text; + len = strlen (text); + } + + while (history_completion_array && history_completion_array[local_index]) + { + if (strncmp (text, history_completion_array[local_index++], len) == 0) + return (savestring (history_completion_array[local_index - 1])); + } + return ((char *)NULL); +} + +static int +dynamic_complete_history (count, key) + int count, key; +{ + int r; + rl_compentry_func_t *orig_func; + rl_completion_func_t *orig_attempt_func; + rl_compignore_func_t *orig_ignore_func; + + orig_func = rl_completion_entry_function; + orig_attempt_func = rl_attempted_completion_function; + orig_ignore_func = rl_ignore_some_completions_function; + + rl_completion_entry_function = history_completion_generator; + rl_attempted_completion_function = (rl_completion_func_t *)NULL; + rl_ignore_some_completions_function = filename_completion_ignore; + + /* XXX - use rl_completion_mode here? */ + if (rl_last_func == dynamic_complete_history) + r = rl_complete_internal ('?'); + else + r = rl_complete_internal (TAB); + + rl_completion_entry_function = orig_func; + rl_attempted_completion_function = orig_attempt_func; + rl_ignore_some_completions_function = orig_ignore_func; + + return r; +} + +static int +bash_dabbrev_expand (count, key) + int count, key; +{ + int r, orig_suppress, orig_sort; + rl_compentry_func_t *orig_func; + rl_completion_func_t *orig_attempt_func; + rl_compignore_func_t *orig_ignore_func; + + orig_func = rl_menu_completion_entry_function; + orig_attempt_func = rl_attempted_completion_function; + orig_ignore_func = rl_ignore_some_completions_function; + orig_suppress = rl_completion_suppress_append; + orig_sort = rl_sort_completion_matches; + + rl_menu_completion_entry_function = history_completion_generator; + rl_attempted_completion_function = (rl_completion_func_t *)NULL; + rl_ignore_some_completions_function = filename_completion_ignore; + rl_filename_completion_desired = 0; + rl_completion_suppress_append = 1; + rl_sort_completion_matches = 0; + + /* XXX - use rl_completion_mode here? */ + dabbrev_expand_active = 1; + if (rl_last_func == bash_dabbrev_expand) + rl_last_func = rl_menu_complete; + r = rl_menu_complete (count, key); + dabbrev_expand_active = 0; + + rl_last_func = bash_dabbrev_expand; + rl_menu_completion_entry_function = orig_func; + rl_attempted_completion_function = orig_attempt_func; + rl_ignore_some_completions_function = orig_ignore_func; + rl_completion_suppress_append = orig_suppress; + rl_sort_completion_matches = orig_sort; + + return r; +} + +#if defined (SPECIFIC_COMPLETION_FUNCTIONS) +static int +bash_complete_username (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_username_internal (rl_completion_mode (bash_complete_username)); +} + +static int +bash_possible_username_completions (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_username_internal ('?'); +} + +static int +bash_complete_username_internal (what_to_do) + int what_to_do; +{ + return bash_specific_completion (what_to_do, rl_username_completion_function); +} + +static int +bash_complete_filename (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_filename_internal (rl_completion_mode (bash_complete_filename)); +} + +static int +bash_possible_filename_completions (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_filename_internal ('?'); +} + +static int +bash_complete_filename_internal (what_to_do) + int what_to_do; +{ + rl_compentry_func_t *orig_func; + rl_completion_func_t *orig_attempt_func; + rl_icppfunc_t *orig_dir_func; + rl_compignore_func_t *orig_ignore_func; + /*const*/ char *orig_rl_completer_word_break_characters; + int r; + + orig_func = rl_completion_entry_function; + orig_attempt_func = rl_attempted_completion_function; + orig_ignore_func = rl_ignore_some_completions_function; + orig_rl_completer_word_break_characters = rl_completer_word_break_characters; + + orig_dir_func = save_directory_hook (); + + rl_completion_entry_function = rl_filename_completion_function; + rl_attempted_completion_function = (rl_completion_func_t *)NULL; + rl_ignore_some_completions_function = filename_completion_ignore; + rl_completer_word_break_characters = " \t\n\"\'"; + + r = rl_complete_internal (what_to_do); + + rl_completion_entry_function = orig_func; + rl_attempted_completion_function = orig_attempt_func; + rl_ignore_some_completions_function = orig_ignore_func; + rl_completer_word_break_characters = orig_rl_completer_word_break_characters; + + restore_directory_hook (orig_dir_func); + + return r; +} + +static int +bash_complete_hostname (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_hostname_internal (rl_completion_mode (bash_complete_hostname)); +} + +static int +bash_possible_hostname_completions (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_hostname_internal ('?'); +} + +static int +bash_complete_variable (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_variable_internal (rl_completion_mode (bash_complete_variable)); +} + +static int +bash_possible_variable_completions (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_variable_internal ('?'); +} + +static int +bash_complete_command (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_command_internal (rl_completion_mode (bash_complete_command)); +} + +static int +bash_possible_command_completions (ignore, ignore2) + int ignore, ignore2; +{ + return bash_complete_command_internal ('?'); +} + +static int +bash_complete_hostname_internal (what_to_do) + int what_to_do; +{ + return bash_specific_completion (what_to_do, hostname_completion_function); +} + +static int +bash_complete_variable_internal (what_to_do) + int what_to_do; +{ + return bash_specific_completion (what_to_do, variable_completion_function); +} + +static int +bash_complete_command_internal (what_to_do) + int what_to_do; +{ + return bash_specific_completion (what_to_do, command_word_completion_function); +} + +static char *globtext; +static char *globorig; + +static char * +glob_complete_word (text, state) + const char *text; + int state; +{ + static char **matches = (char **)NULL; + static int ind; + int glen; + char *ret, *ttext; + + if (state == 0) + { + rl_filename_completion_desired = 1; + FREE (matches); + if (globorig != globtext) + FREE (globorig); + FREE (globtext); + + ttext = bash_tilde_expand (text, 0); + + if (rl_explicit_arg) + { + globorig = savestring (ttext); + glen = strlen (ttext); + globtext = (char *)xmalloc (glen + 2); + strcpy (globtext, ttext); + globtext[glen] = '*'; + globtext[glen+1] = '\0'; + } + else + globtext = globorig = savestring (ttext); + + if (ttext != text) + free (ttext); + + matches = shell_glob_filename (globtext); + if (GLOB_FAILED (matches)) + matches = (char **)NULL; + ind = 0; + } + + ret = matches ? matches[ind] : (char *)NULL; + ind++; + return ret; +} + +static int +bash_glob_completion_internal (what_to_do) + int what_to_do; +{ + return bash_specific_completion (what_to_do, glob_complete_word); +} + +/* A special quoting function so we don't end up quoting globbing characters + in the word if there are no matches or multiple matches. */ +static char * +bash_glob_quote_filename (s, rtype, qcp) + char *s; + int rtype; + char *qcp; +{ + if (globorig && qcp && *qcp == '\0' && STREQ (s, globorig)) + return (savestring (s)); + else + return (bash_quote_filename (s, rtype, qcp)); +} + +static int +bash_glob_complete_word (count, key) + int count, key; +{ + int r; + rl_quote_func_t *orig_quoting_function; + + if (rl_editing_mode == EMACS_EDITING_MODE) + rl_explicit_arg = 1; /* force `*' append */ + orig_quoting_function = rl_filename_quoting_function; + rl_filename_quoting_function = bash_glob_quote_filename; + + r = bash_glob_completion_internal (rl_completion_mode (bash_glob_complete_word)); + + rl_filename_quoting_function = orig_quoting_function; + return r; +} + +static int +bash_glob_expand_word (count, key) + int count, key; +{ + return bash_glob_completion_internal ('*'); +} + +static int +bash_glob_list_expansions (count, key) + int count, key; +{ + return bash_glob_completion_internal ('?'); +} + +static int +bash_specific_completion (what_to_do, generator) + int what_to_do; + rl_compentry_func_t *generator; +{ + rl_compentry_func_t *orig_func; + rl_completion_func_t *orig_attempt_func; + rl_compignore_func_t *orig_ignore_func; + int r; + + orig_func = rl_completion_entry_function; + orig_attempt_func = rl_attempted_completion_function; + orig_ignore_func = rl_ignore_some_completions_function; + rl_completion_entry_function = generator; + rl_attempted_completion_function = NULL; + rl_ignore_some_completions_function = orig_ignore_func; + + r = rl_complete_internal (what_to_do); + + rl_completion_entry_function = orig_func; + rl_attempted_completion_function = orig_attempt_func; + rl_ignore_some_completions_function = orig_ignore_func; + + return r; +} + +#endif /* SPECIFIC_COMPLETION_FUNCTIONS */ + +#if defined (VI_MODE) +/* Completion, from vi mode's point of view. This is a modified version of + rl_vi_complete which uses the bash globbing code to implement what POSIX + specifies, which is to append a `*' and attempt filename generation (which + has the side effect of expanding any globbing characters in the word). */ +static int +bash_vi_complete (count, key) + int count, key; +{ +#if defined (SPECIFIC_COMPLETION_FUNCTIONS) + int p, r; + char *t; + + if ((rl_point < rl_end) && (!whitespace (rl_line_buffer[rl_point]))) + { + if (!whitespace (rl_line_buffer[rl_point + 1])) + rl_vi_end_word (1, 'E'); + rl_point++; + } + + /* Find boundaries of current word, according to vi definition of a + `bigword'. */ + t = 0; + if (rl_point > 0) + { + p = rl_point; + rl_vi_bWord (1, 'B'); + r = rl_point; + rl_point = p; + p = r; + + t = substring (rl_line_buffer, p, rl_point); + } + + if (t && glob_pattern_p (t) == 0) + rl_explicit_arg = 1; /* XXX - force glob_complete_word to append `*' */ + FREE (t); + + if (key == '*') /* Expansion and replacement. */ + r = bash_glob_expand_word (count, key); + else if (key == '=') /* List possible completions. */ + r = bash_glob_list_expansions (count, key); + else if (key == '\\') /* Standard completion */ + r = bash_glob_complete_word (count, key); + else + r = rl_complete (0, key); + + if (key == '*' || key == '\\') + rl_vi_start_inserting (key, 1, 1); + + return (r); +#else + return rl_vi_complete (count, key); +#endif /* !SPECIFIC_COMPLETION_FUNCTIONS */ +} +#endif /* VI_MODE */ + +/* Filename quoting for completion. */ +/* A function to strip unquoted quote characters (single quotes, double + quotes, and backslashes). It allows single quotes to appear + within double quotes, and vice versa. It should be smarter. */ +static char * +bash_dequote_filename (text, quote_char) + char *text; + int quote_char; +{ + char *ret, *p, *r; + int l, quoted; + + l = strlen (text); + ret = (char *)xmalloc (l + 1); + for (quoted = quote_char, p = text, r = ret; p && *p; p++) + { + /* Allow backslash-escaped characters to pass through unscathed. */ + if (*p == '\\') + { + /* Backslashes are preserved within single quotes. */ + if (quoted == '\'') + *r++ = *p; + /* Backslashes are preserved within double quotes unless the + character is one that is defined to be escaped */ + else if (quoted == '"' && ((sh_syntaxtab[p[1]] & CBSDQUOTE) == 0)) + *r++ = *p; + + *r++ = *++p; + if (*p == '\0') + return ret; /* XXX - was break; */ + continue; + } + /* Close quote. */ + if (quoted && *p == quoted) + { + quoted = 0; + continue; + } + /* Open quote. */ + if (quoted == 0 && (*p == '\'' || *p == '"')) + { + quoted = *p; + continue; + } + *r++ = *p; + } + *r = '\0'; + return ret; +} + +/* Quote characters that the readline completion code would treat as + word break characters with backslashes. Pass backslash-quoted + characters through without examination. */ +static char * +quote_word_break_chars (text) + char *text; +{ + char *ret, *r, *s; + int l; + + l = strlen (text); + ret = (char *)xmalloc ((2 * l) + 1); + for (s = text, r = ret; *s; s++) + { + /* Pass backslash-quoted characters through, including the backslash. */ + if (*s == '\\') + { + *r++ = '\\'; + *r++ = *++s; + if (*s == '\0') + break; + continue; + } + /* OK, we have an unquoted character. Check its presence in + rl_completer_word_break_characters. */ + if (mbschr (rl_completer_word_break_characters, *s)) + *r++ = '\\'; + /* XXX -- check for standalone tildes here and backslash-quote them */ + if (s == text && *s == '~' && file_exists (text)) + *r++ = '\\'; + *r++ = *s; + } + *r = '\0'; + return ret; +} + +/* Use characters in STRING to populate the table of characters that should + be backslash-quoted. The table will be used for sh_backslash_quote from + this file. */ +static void +set_filename_bstab (string) + const char *string; +{ + const char *s; + + memset (filename_bstab, 0, sizeof (filename_bstab)); + for (s = string; s && *s; s++) + filename_bstab[*s] = 1; +} + +/* Quote a filename using double quotes, single quotes, or backslashes + depending on the value of completion_quoting_style. If we're + completing using backslashes, we need to quote some additional + characters (those that readline treats as word breaks), so we call + quote_word_break_chars on the result. This returns newly-allocated + memory. */ +static char * +bash_quote_filename (s, rtype, qcp) + char *s; + int rtype; + char *qcp; +{ + char *rtext, *mtext, *ret; + int rlen, cs; + + rtext = (char *)NULL; + + /* If RTYPE == MULT_MATCH, it means that there is + more than one match. In this case, we do not add + the closing quote or attempt to perform tilde + expansion. If RTYPE == SINGLE_MATCH, we try + to perform tilde expansion, because single and double + quotes inhibit tilde expansion by the shell. */ + + cs = completion_quoting_style; + /* Might need to modify the default completion style based on *qcp, + since it's set to any user-provided opening quote. We also change + to single-quoting if there is no user-provided opening quote and + the word being completed contains newlines, since those are not + quoted correctly using backslashes (a backslash-newline pair is + special to the shell parser). */ + if (*qcp == '\0' && cs == COMPLETE_BSQUOTE && mbschr (s, '\n')) + cs = COMPLETE_SQUOTE; + else if (*qcp == '"') + cs = COMPLETE_DQUOTE; + else if (*qcp == '\'') + cs = COMPLETE_SQUOTE; +#if defined (BANG_HISTORY) + else if (*qcp == '\0' && history_expansion && cs == COMPLETE_DQUOTE && + history_expansion_inhibited == 0 && mbschr (s, '!')) + cs = COMPLETE_BSQUOTE; + + if (*qcp == '"' && history_expansion && cs == COMPLETE_DQUOTE && + history_expansion_inhibited == 0 && mbschr (s, '!')) + { + cs = COMPLETE_BSQUOTE; + *qcp = '\0'; + } +#endif + + /* Don't tilde-expand backslash-quoted filenames, since only single and + double quotes inhibit tilde expansion. */ + mtext = s; + if (mtext[0] == '~' && rtype == SINGLE_MATCH && cs != COMPLETE_BSQUOTE) + mtext = bash_tilde_expand (s, 0); + + switch (cs) + { + case COMPLETE_DQUOTE: + rtext = sh_double_quote (mtext); + break; + case COMPLETE_SQUOTE: + rtext = sh_single_quote (mtext); + break; + case COMPLETE_BSQUOTE: + rtext = sh_backslash_quote (mtext, complete_fullquote ? 0 : filename_bstab, 0); + break; + } + + if (mtext != s) + free (mtext); + + /* We may need to quote additional characters: those that readline treats + as word breaks that are not quoted by backslash_quote. */ + if (rtext && cs == COMPLETE_BSQUOTE) + { + mtext = quote_word_break_chars (rtext); + free (rtext); + rtext = mtext; + } + + /* Leave the opening quote intact. The readline completion code takes + care of avoiding doubled opening quotes. */ + if (rtext) + { + rlen = strlen (rtext); + ret = (char *)xmalloc (rlen + 1); + strcpy (ret, rtext); + } + else + { + ret = (char *)xmalloc (rlen = 1); + ret[0] = '\0'; + } + + /* If there are multiple matches, cut off the closing quote. */ + if (rtype == MULT_MATCH && cs != COMPLETE_BSQUOTE) + ret[rlen - 1] = '\0'; + free (rtext); + return ret; +} + +/* Support for binding readline key sequences to Unix commands. */ +static Keymap cmd_xmap; + +#ifdef _MINIX +static void +#else +static int +#endif +putx(c) + int c; +{ + int x; + x = putc (c, rl_outstream); +#ifndef _MINIX + return x; +#endif +} + +static int +bash_execute_unix_command (count, key) + int count; /* ignored */ + int key; +{ + Keymap ckmap; /* current keymap */ + Keymap xkmap; /* unix command executing keymap */ + rl_command_func_t *func; + int type; + register int i, r; + intmax_t mi; + sh_parser_state_t ps; + char *cmd, *value, *l, *l1, *ce; + SHELL_VAR *v; + char ibuf[INT_STRLEN_BOUND(int) + 1]; + + /* First, we need to find the right command to execute. This is tricky, + because we might have already indirected into another keymap, so we + have to walk cmd_xmap using the entire key sequence. */ + cmd = (char *)rl_function_of_keyseq (rl_executing_keyseq, cmd_xmap, &type); + + if (cmd == 0 || type != ISMACR) + { + rl_crlf (); + internal_error (_("bash_execute_unix_command: cannot find keymap for command")); + rl_forced_update_display (); + return 1; + } + + ce = rl_get_termcap ("ce"); + if (ce) /* clear current line */ + { + fprintf (rl_outstream, "\r"); + tputs (ce, 1, putx); + fflush (rl_outstream); + } + else + rl_crlf (); /* move to a new line */ + + v = bind_variable ("READLINE_LINE", rl_line_buffer, 0); + if (v) + VSETATTR (v, att_exported); + l = v ? value_cell (v) : 0; + value = inttostr (rl_point, ibuf, sizeof (ibuf)); + v = bind_int_variable ("READLINE_POINT", value); + if (v) + VSETATTR (v, att_exported); + array_needs_making = 1; + + save_parser_state (&ps); + r = parse_and_execute (cmd, "bash_execute_unix_command", SEVAL_NOHIST|SEVAL_NOFREE); + restore_parser_state (&ps); + + v = find_variable ("READLINE_LINE"); + l1 = v ? value_cell (v) : 0; + if (l1 != l) + maybe_make_readline_line (value_cell (v)); + v = find_variable ("READLINE_POINT"); + if (v && legal_number (value_cell (v), &mi)) + { + i = mi; + if (i != rl_point) + { + rl_point = i; + if (rl_point > rl_end) + rl_point = rl_end; + else if (rl_point < 0) + rl_point = 0; + } + } + + unbind_variable ("READLINE_LINE"); + unbind_variable ("READLINE_POINT"); + array_needs_making = 1; + + /* and restore the readline buffer and display after command execution. */ + rl_forced_update_display (); + return 0; +} + +int +print_unix_command_map () +{ + Keymap save; + + save = rl_get_keymap (); + rl_set_keymap (cmd_xmap); + rl_macro_dumper (1); + rl_set_keymap (save); + return 0; +} + +static void +init_unix_command_map () +{ + cmd_xmap = rl_make_bare_keymap (); +} + +static int +isolate_sequence (string, ind, need_dquote, startp) + char *string; + int ind, need_dquote, *startp; +{ + register int i; + int c, passc, delim; + + for (i = ind; string[i] && whitespace (string[i]); i++) + ; + /* NEED_DQUOTE means that the first non-white character *must* be `"'. */ + if (need_dquote && string[i] != '"') + { + builtin_error (_("%s: first non-whitespace character is not `\"'"), string); + return -1; + } + + /* We can have delimited strings even if NEED_DQUOTE == 0, like the command + string to bind the key sequence to. */ + delim = (string[i] == '"' || string[i] == '\'') ? string[i] : 0; + + if (startp) + *startp = delim ? ++i : i; + + for (passc = 0; c = string[i]; i++) + { + if (passc) + { + passc = 0; + continue; + } + if (c == '\\') + { + passc++; + continue; + } + if (c == delim) + break; + } + + if (delim && string[i] != delim) + { + builtin_error (_("no closing `%c' in %s"), delim, string); + return -1; + } + + return i; +} + +int +bind_keyseq_to_unix_command (line) + char *line; +{ + Keymap kmap; + char *kseq, *value; + int i, kstart; + + if (cmd_xmap == 0) + init_unix_command_map (); + + kmap = rl_get_keymap (); + + /* We duplicate some of the work done by rl_parse_and_bind here, but + this code only has to handle `"keyseq": ["]command["]' and can + generate an error for anything else. */ + i = isolate_sequence (line, 0, 1, &kstart); + if (i < 0) + return -1; + + /* Create the key sequence string to pass to rl_generic_bind */ + kseq = substring (line, kstart, i); + + for ( ; line[i] && line[i] != ':'; i++) + ; + if (line[i] != ':') + { + builtin_error (_("%s: missing colon separator"), line); + FREE (kseq); + return -1; + } + + i = isolate_sequence (line, i + 1, 0, &kstart); + if (i < 0) + { + FREE (kseq); + return -1; + } + + /* Create the value string containing the command to execute. */ + value = substring (line, kstart, i); + + /* Save the command to execute and the key sequence in the CMD_XMAP */ + rl_generic_bind (ISMACR, kseq, value, cmd_xmap); + + /* and bind the key sequence in the current keymap to a function that + understands how to execute from CMD_XMAP */ + rl_bind_keyseq_in_map (kseq, bash_execute_unix_command, kmap); + + free (kseq); + return 0; +} + +/* Used by the programmable completion code. Complete TEXT as a filename, + but return only directories as matches. Dequotes the filename before + attempting to find matches. */ +char ** +bash_directory_completion_matches (text) + const char *text; +{ + char **m1; + char *dfn; + int qc; + + qc = rl_dispatching ? rl_completion_quote_character : 0; + /* If rl_completion_found_quote != 0, rl_completion_matches will call the + filename dequoting function, causing the directory name to be dequoted + twice. */ + if (rl_dispatching && rl_completion_found_quote == 0) + dfn = bash_dequote_filename ((char *)text, qc); + else + dfn = (char *)text; + m1 = rl_completion_matches (dfn, rl_filename_completion_function); + if (dfn != text) + free (dfn); + + if (m1 == 0 || m1[0] == 0) + return m1; + /* We don't bother recomputing the lcd of the matches, because it will just + get thrown away by the programmable completion code and recomputed + later. */ + (void)bash_ignore_filenames (m1); + return m1; +} + +char * +bash_dequote_text (text) + const char *text; +{ + char *dtxt; + int qc; + + qc = (text[0] == '"' || text[0] == '\'') ? text[0] : 0; + dtxt = bash_dequote_filename ((char *)text, qc); + return (dtxt); +} + +/* This event hook is designed to be called after readline receives a signal + that interrupts read(2). It gives reasonable responsiveness to interrupts + and fatal signals without executing too much code in a signal handler + context. */ +static int +bash_event_hook () +{ + /* If we're going to longjmp to top_level, make sure we clean up readline. + check_signals will call QUIT, which will eventually longjmp to top_level, + calling run_interrupt_trap along the way. The check for sigalrm_seen is + to clean up the read builtin's state. */ + if (interrupt_state || sigalrm_seen) + rl_cleanup_after_signal (); + bashline_reset_event_hook (); + check_signals_and_traps (); /* XXX */ + return 0; +} + +#endif /* READLINE */ diff --git a/builtins/bashgetopt.c b/builtins/bashgetopt.c index b1b707060..405ced437 100644 --- a/builtins/bashgetopt.c +++ b/builtins/bashgetopt.c @@ -31,6 +31,8 @@ #include "../shell.h" #include "common.h" +#include "bashgetopt.h" + #define ISOPT(s) (((*(s) == '-') || (plus && *(s) == '+')) && (s)[1]) #define NOTOPT(s) (((*(s) != '-') && (!plus || *(s) != '+')) || (s)[1] == '\0') @@ -76,6 +78,10 @@ char *opts; lhead = (WORD_LIST *)NULL; loptend = lcurrent; return(-1); + } else if (ISHELP (lcurrent->word->word)) { + lhead = (WORD_LIST *)NULL; + loptend = lcurrent; + return (GETOPT_HELP); } else if (lcurrent->word->word[0] == '-' && lcurrent->word->word[1] == '-' && lcurrent->word->word[2] == 0) { diff --git a/builtins/bashgetopt.c~ b/builtins/bashgetopt.c~ new file mode 100644 index 000000000..faa841758 --- /dev/null +++ b/builtins/bashgetopt.c~ @@ -0,0 +1,179 @@ +/* bashgetopt.c -- `getopt' for use by the builtins. */ + +/* Copyright (C) 1992-2002 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 3 of the License, 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. If not, see . +*/ + +#include + +#if defined (HAVE_UNISTD_H) +# include +#endif + +#include "../bashansi.h" +#include +#include + +#include "../shell.h" +#include "common.h" + +#define ISOPT(s) (((*(s) == '-') || (plus && *(s) == '+')) && (s)[1]) +#define NOTOPT(s) (((*(s) != '-') && (!plus || *(s) != '+')) || (s)[1] == '\0') + +static int sp; + +char *list_optarg; +int list_optopt; +int list_opttype; + +static WORD_LIST *lhead = (WORD_LIST *)NULL; +WORD_LIST *lcurrent = (WORD_LIST *)NULL; +WORD_LIST *loptend; /* Points to the first non-option argument in the list */ + +int +internal_getopt(list, opts) +WORD_LIST *list; +char *opts; +{ + register int c; + register char *cp; + int plus; /* nonzero means to handle +option */ + static char errstr[3] = { '-', '\0', '\0' }; + + plus = *opts == '+'; + if (plus) + opts++; + + if (list == 0) { + list_optarg = (char *)NULL; + loptend = (WORD_LIST *)NULL; /* No non-option arguments */ + return -1; + } + + if (list != lhead || lhead == 0) { + /* Hmmm.... called with a different word list. Reset. */ + sp = 1; + lcurrent = lhead = list; + loptend = (WORD_LIST *)NULL; + } + + if (sp == 1) { + if (lcurrent == 0 || NOTOPT(lcurrent->word->word)) { + lhead = (WORD_LIST *)NULL; + loptend = lcurrent; + return(-1); + } else if (ISHELP (lcurrent->word->word)) { + lhead = (WORD_LIST *)NULL; + loptend = lcurrent; + return (GETOPT_HELP); + } else if (lcurrent->word->word[0] == '-' && + lcurrent->word->word[1] == '-' && + lcurrent->word->word[2] == 0) { + lhead = (WORD_LIST *)NULL; + loptend = lcurrent->next; + return(-1); + } + errstr[0] = list_opttype = lcurrent->word->word[0]; + } + + list_optopt = c = lcurrent->word->word[sp]; + + if (c == ':' || (cp = strchr(opts, c)) == NULL) { + errstr[1] = c; + sh_invalidopt (errstr); + if (lcurrent->word->word[++sp] == '\0') { + lcurrent = lcurrent->next; + sp = 1; + } + list_optarg = NULL; + if (lcurrent) + loptend = lcurrent->next; + return('?'); + } + + if (*++cp == ':' || *cp == ';') { + /* `:': Option requires an argument. */ + /* `;': option argument may be missing */ + /* We allow -l2 as equivalent to -l 2 */ + if (lcurrent->word->word[sp+1]) { + list_optarg = lcurrent->word->word + sp + 1; + lcurrent = lcurrent->next; + /* If the specifier is `;', don't set optarg if the next + argument looks like another option. */ +#if 0 + } else if (lcurrent->next && (*cp == ':' || lcurrent->next->word->word[0] != '-')) { +#else + } else if (lcurrent->next && (*cp == ':' || NOTOPT(lcurrent->next->word->word))) { +#endif + lcurrent = lcurrent->next; + list_optarg = lcurrent->word->word; + lcurrent = lcurrent->next; + } else if (*cp == ';') { + list_optarg = (char *)NULL; + lcurrent = lcurrent->next; + } else { /* lcurrent->next == NULL */ + errstr[1] = c; + sh_needarg (errstr); + sp = 1; + list_optarg = (char *)NULL; + return('?'); + } + sp = 1; + } else if (*cp == '#') { + /* option requires a numeric argument */ + if (lcurrent->word->word[sp+1]) { + if (DIGIT(lcurrent->word->word[sp+1])) { + list_optarg = lcurrent->word->word + sp + 1; + lcurrent = lcurrent->next; + } else + list_optarg = (char *)NULL; + } else { + if (lcurrent->next && legal_number(lcurrent->next->word->word, (intmax_t *)0)) { + lcurrent = lcurrent->next; + list_optarg = lcurrent->word->word; + lcurrent = lcurrent->next; + } else { + errstr[1] = c; + sh_neednumarg (errstr); + sp = 1; + list_optarg = (char *)NULL; + return ('?'); + } + } + + } else { + /* No argument, just return the option. */ + if (lcurrent->word->word[++sp] == '\0') { + sp = 1; + lcurrent = lcurrent->next; + } + list_optarg = (char *)NULL; + } + + return(c); +} + +/* + * reset_internal_getopt -- force the in[ft]ernal getopt to reset + */ + +void +reset_internal_getopt () +{ + lhead = lcurrent = loptend = (WORD_LIST *)NULL; + sp = 1; +} diff --git a/builtins/bashgetopt.h b/builtins/bashgetopt.h index f2aea2668..6637b429e 100644 --- a/builtins/bashgetopt.h +++ b/builtins/bashgetopt.h @@ -25,6 +25,9 @@ #include +#define GETOPT_EOF -1 +#define GETOPT_HELP -99 + extern char *list_optarg; extern int list_optopt; diff --git a/builtins/bashgetopt.h~ b/builtins/bashgetopt.h~ new file mode 100644 index 000000000..f2aea2668 --- /dev/null +++ b/builtins/bashgetopt.h~ @@ -0,0 +1,39 @@ +/* bashgetopt.h -- extern declarations for stuff defined in bashgetopt.c. */ + +/* 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 3 of the License, 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. If not, see . +*/ + +/* See getopt.h for the explanation of these variables. */ + +#if !defined (__BASH_GETOPT_H) +# define __BASH_GETOPT_H + +#include + +extern char *list_optarg; + +extern int list_optopt; +extern int list_opttype; + +extern WORD_LIST *lcurrent; +extern WORD_LIST *loptend; + +extern int internal_getopt __P((WORD_LIST *, char *)); +extern void reset_internal_getopt __P((void)); + +#endif /* !__BASH_GETOPT_H */ diff --git a/builtins/bind.def b/builtins/bind.def index 7ea5c090e..42e3f78a6 100644 --- a/builtins/bind.def +++ b/builtins/bind.def @@ -1,7 +1,7 @@ This file is bind.def, from which is created bind.c. It implements the builtin "bind" in Bash. -Copyright (C) 1987-2009 Free Software Foundation, Inc. +Copyright (C) 1987-2014 Free Software Foundation, Inc. This file is part of GNU Bash, the Bourne Again SHell. @@ -141,7 +141,7 @@ bind_builtin (list) rl_outstream = stdout; reset_internal_getopt (); - while ((opt = internal_getopt (list, "lvpVPsSXf:q:u:m:r:x:")) != EOF) + while ((opt = internal_getopt (list, "lvpVPsSXf:q:u:m:r:x:")) != -1) { switch (opt) { diff --git a/builtins/break.def b/builtins/break.def index 232ac1a71..bdc1182a8 100644 --- a/builtins/break.def +++ b/builtins/break.def @@ -67,6 +67,8 @@ break_builtin (list) { intmax_t newbreak; + CHECK_HELPOPT (list); + if (check_loop_level () == 0) return (EXECUTION_SUCCESS); @@ -107,6 +109,8 @@ continue_builtin (list) { intmax_t newcont; + CHECK_HELPOPT (list); + if (check_loop_level () == 0) return (EXECUTION_SUCCESS); diff --git a/builtins/break.def~ b/builtins/break.def~ new file mode 100644 index 000000000..232ac1a71 --- /dev/null +++ b/builtins/break.def~ @@ -0,0 +1,141 @@ +This file is break.def, from which is created break.c. +It implements the builtins "break" and "continue" in Bash. + +Copyright (C) 1987-2009 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 3 of the License, 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. If not, see . + +$PRODUCES break.c + +$BUILTIN break +$FUNCTION break_builtin +$SHORT_DOC break [n] +Exit for, while, or until loops. + +Exit a FOR, WHILE or UNTIL loop. If N is specified, break N enclosing +loops. + +Exit Status: +The exit status is 0 unless N is not greater than or equal to 1. +$END +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashintl.h" + +#include "../shell.h" +#include "common.h" + +extern char *this_command_name; +extern int posixly_correct; + +static int check_loop_level __P((void)); + +/* The depth of while's and until's. */ +int loop_level = 0; + +/* Non-zero when a "break" instruction is encountered. */ +int breaking = 0; + +/* Non-zero when we have encountered a continue instruction. */ +int continuing = 0; + +/* Set up to break x levels, where x defaults to 1, but can be specified + as the first argument. */ +int +break_builtin (list) + WORD_LIST *list; +{ + intmax_t newbreak; + + if (check_loop_level () == 0) + return (EXECUTION_SUCCESS); + + (void)get_numeric_arg (list, 1, &newbreak); + + if (newbreak <= 0) + { + sh_erange (list->word->word, _("loop count")); + breaking = loop_level; + return (EXECUTION_FAILURE); + } + + if (newbreak > loop_level) + newbreak = loop_level; + + breaking = newbreak; + + return (EXECUTION_SUCCESS); +} + +$BUILTIN continue +$FUNCTION continue_builtin +$SHORT_DOC continue [n] +Resume for, while, or until loops. + +Resumes the next iteration of the enclosing FOR, WHILE or UNTIL loop. +If N is specified, resumes the Nth enclosing loop. + +Exit Status: +The exit status is 0 unless N is not greater than or equal to 1. +$END + +/* Set up to continue x levels, where x defaults to 1, but can be specified + as the first argument. */ +int +continue_builtin (list) + WORD_LIST *list; +{ + intmax_t newcont; + + if (check_loop_level () == 0) + return (EXECUTION_SUCCESS); + + (void)get_numeric_arg (list, 1, &newcont); + + if (newcont <= 0) + { + sh_erange (list->word->word, _("loop count")); + breaking = loop_level; + return (EXECUTION_FAILURE); + } + + if (newcont > loop_level) + newcont = loop_level; + + continuing = newcont; + + return (EXECUTION_SUCCESS); +} + +/* Return non-zero if a break or continue command would be okay. + Print an error message if break or continue is meaningless here. */ +static int +check_loop_level () +{ +#if defined (BREAK_COMPLAINS) + if (loop_level == 0 && posixly_correct == 0) + builtin_error (_("only meaningful in a `for', `while', or `until' loop")); +#endif /* BREAK_COMPLAINS */ + + return (loop_level); +} diff --git a/builtins/caller.def b/builtins/caller.def index 965676b38..bf5eb96f8 100644 --- a/builtins/caller.def +++ b/builtins/caller.def @@ -81,6 +81,8 @@ caller_builtin (list) char *funcname_s, *source_s, *lineno_s; intmax_t num; + CHECK_HELPOPT (list); + GET_ARRAY_FROM_VAR ("FUNCNAME", funcname_v, funcname_a); GET_ARRAY_FROM_VAR ("BASH_SOURCE", bash_source_v, bash_source_a); GET_ARRAY_FROM_VAR ("BASH_LINENO", bash_lineno_v, bash_lineno_a); diff --git a/builtins/caller.def~ b/builtins/caller.def~ new file mode 100644 index 000000000..638f5c475 --- /dev/null +++ b/builtins/caller.def~ @@ -0,0 +1,160 @@ +This file is caller.def, from which is created caller.c. It implements the +builtin "caller" in Bash. + +Copyright (C) 2002-2008 Rocky Bernstein for Free Software Foundation, Inc. +Copyright (C) 2008-2013 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 3 of the License, 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. If not, see . + +$PRODUCES caller.c + +$BUILTIN caller +$FUNCTION caller_builtin +$DEPENDS_ON DEBUGGER +$SHORT_DOC caller [expr] +Return the context of the current subroutine call. + +Without EXPR, returns "$line $filename". With EXPR, returns +"$line $subroutine $filename"; this extra information can be used to +provide a stack trace. + +The value of EXPR indicates how many call frames to go back before the +current one; the top frame is frame 0. + +Exit Status: +Returns 0 unless the shell is not executing a shell function or EXPR +is invalid. +$END + +#include +#include +#include "chartypes.h" +#include "bashtypes.h" + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include + +#include "../bashintl.h" + +#include "../shell.h" +#include "common.h" +#include "builtext.h" +#include "bashgetopt.h" + +#ifdef LOADABLE_BUILTIN +# include "builtins.h" +#endif + +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +int +caller_builtin (list) + WORD_LIST *list; +{ +#if !defined (ARRAY_VARS) + printf ("1 NULL\n"); + return (EXECUTION_FAILURE); +#else + SHELL_VAR *funcname_v, *bash_source_v, *bash_lineno_v; + ARRAY *funcname_a, *bash_source_a, *bash_lineno_a; + char *funcname_s, *source_s, *lineno_s; + intmax_t num; + + if (list && list->word && ISHELP (list->word->word)) + { + builtin_help (); + return (EX_USAGE); + } + + GET_ARRAY_FROM_VAR ("FUNCNAME", funcname_v, funcname_a); + GET_ARRAY_FROM_VAR ("BASH_SOURCE", bash_source_v, bash_source_a); + GET_ARRAY_FROM_VAR ("BASH_LINENO", bash_lineno_v, bash_lineno_a); + + if (bash_lineno_a == 0 || array_empty (bash_lineno_a)) + return (EXECUTION_FAILURE); + + if (bash_source_a == 0 || array_empty (bash_source_a)) + return (EXECUTION_FAILURE); + + if (no_options (list)) + return (EX_USAGE); + list = loptend; /* skip over possible `--' */ + + /* If there is no argument list, then give short form: line filename. */ + if (list == 0) + { + lineno_s = array_reference (bash_lineno_a, 0); + source_s = array_reference (bash_source_a, 1); + printf("%s %s\n", lineno_s ? lineno_s : "NULL", source_s ? source_s : "NULL"); + return (EXECUTION_SUCCESS); + } + + if (funcname_a == 0 || array_empty (funcname_a)) + return (EXECUTION_FAILURE); + + if (legal_number (list->word->word, &num)) + { + lineno_s = array_reference (bash_lineno_a, num); + source_s = array_reference (bash_source_a, num+1); + funcname_s = array_reference (funcname_a, num+1); + + if (lineno_s == NULL|| source_s == NULL || funcname_s == NULL) + return (EXECUTION_FAILURE); + + printf("%s %s %s\n", lineno_s, funcname_s, source_s); + } + else + { + sh_invalidnum (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + + return (EXECUTION_SUCCESS); +#endif +} + +#ifdef LOADABLE_BUILTIN +static char *caller_doc[] = { +N_("Returns the context of the current subroutine call.\n\ + \n\ + Without EXPR, returns "$line $filename". With EXPR, returns\n\ + "$line $subroutine $filename"; this extra information can be used to\n\ + provide a stack trace.\n\ + \n\ + The value of EXPR indicates how many call frames to go back before the\n\ + current one; the top frame is frame 0."), + (char *)NULL +}; + +struct builtin caller_struct = { + "caller", + caller_builtin, + BUILTIN_ENABLED, + caller_doc, + "caller [EXPR]", + 0 +}; + +#endif /* LOADABLE_BUILTIN */ diff --git a/builtins/command.def b/builtins/command.def index 184527994..00309c2d7 100644 --- a/builtins/command.def +++ b/builtins/command.def @@ -90,6 +90,7 @@ command_builtin (list) case 'v': verbose = CDESC_REUSABLE; /* ditto */ break; + CASE_HELPOPT(); default: builtin_usage (); return (EX_USAGE); diff --git a/builtins/command.def~ b/builtins/command.def~ new file mode 100644 index 000000000..184527994 --- /dev/null +++ b/builtins/command.def~ @@ -0,0 +1,219 @@ +This file is command.def, from which is created command.c. +It implements the builtin "command" in Bash. + +Copyright (C) 1987-2009 Free Software Foundation, Inc. + +This file is part of GNU Bash, the Bourne Again SHell. + +Bash is free software: you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation, either version 3 of the License, or +(at your option) any later version. + +Bash is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with Bash. If not, see . + +$PRODUCES command.c + +$BUILTIN command +$FUNCTION command_builtin +$SHORT_DOC command [-pVv] command [arg ...] +Execute a simple command or display information about commands. + +Runs COMMAND with ARGS suppressing shell function lookup, or display +information about the specified COMMANDs. Can be used to invoke commands +on disk when a function with the same name exists. + +Options: + -p use a default value for PATH that is guaranteed to find all of + the standard utilities + -v print a description of COMMAND similar to the `type' builtin + -V print a more verbose description of each COMMAND + +Exit Status: +Returns exit status of COMMAND, or failure if COMMAND is not found. +$END + +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashansi.h" + +#include "../shell.h" +#include "../execute_cmd.h" +#include "../flags.h" +#include "bashgetopt.h" +#include "common.h" + +#if defined (_CS_PATH) && defined (HAVE_CONFSTR) && !HAVE_DECL_CONFSTR +extern size_t confstr __P((int, char *, size_t)); +#endif + +extern int subshell_environment; + +static void restore_path __P((char *)); +static char *get_standard_path __P((void)); + +/* Run the commands mentioned in LIST without paying attention to shell + functions. */ +int +command_builtin (list) + WORD_LIST *list; +{ + int result, verbose, use_standard_path, opt; + char *old_path, *standard_path; + COMMAND *command; + + verbose = use_standard_path = 0; + reset_internal_getopt (); + while ((opt = internal_getopt (list, "pvV")) != -1) + { + switch (opt) + { + case 'p': + use_standard_path = 1; + break; + case 'V': + verbose = CDESC_SHORTDESC|CDESC_ABSPATH; /* look in common.h for constants */ + break; + case 'v': + verbose = CDESC_REUSABLE; /* ditto */ + break; + default: + builtin_usage (); + return (EX_USAGE); + } + } + list = loptend; + + if (list == 0) + return (EXECUTION_SUCCESS); + +#if defined (RESTRICTED_SHELL) + if (use_standard_path && restricted) + { + sh_restricted ("-p"); + return (EXECUTION_FAILURE); + } +#endif + + begin_unwind_frame ("command_builtin"); + + if (use_standard_path) + { + old_path = get_string_value ("PATH"); + /* If old_path is NULL, $PATH is unset. If so, we want to make sure + it's unset after this command completes. */ + if (old_path) + old_path = savestring (old_path); + add_unwind_protect ((Function *)restore_path, old_path); + + standard_path = get_standard_path (); + bind_variable ("PATH", standard_path ? standard_path : "", 0); + stupidly_hack_special_variables ("PATH"); + FREE (standard_path); + } + + if (verbose) + { + int found, any_found; + + for (any_found = 0; list; list = list->next) + { + found = describe_command (list->word->word, verbose); + + if (found == 0 && verbose != CDESC_REUSABLE) + sh_notfound (list->word->word); + + any_found += found; + } + + run_unwind_frame ("command_builtin"); + return (any_found ? EXECUTION_SUCCESS : EXECUTION_FAILURE); + } + +#define COMMAND_BUILTIN_FLAGS (CMD_NO_FUNCTIONS | CMD_INHIBIT_EXPANSION | CMD_COMMAND_BUILTIN) + + /* We don't want this to be reparsed (consider command echo 'foo &'), so + just make a simple_command structure and call execute_command with it. */ + command = make_bare_simple_command (); + command->value.Simple->words = (WORD_LIST *)copy_word_list (list); + command->value.Simple->redirects = (REDIRECT *)NULL; + command->flags |= COMMAND_BUILTIN_FLAGS; + command->value.Simple->flags |= COMMAND_BUILTIN_FLAGS; +#if 0 + /* This breaks for things like ( cd /tmp ; command z ababa ; echo next ) + or $(command echo a ; command echo b;) or even + { command echo a; command echo b; } & */ + /* If we're in a subshell, see if we can get away without forking + again, since we've already forked to run this builtin. */ + if (subshell_environment) + { + command->flags |= CMD_NO_FORK; + command->value.Simple->flags |= CMD_NO_FORK; + } +#endif + add_unwind_protect ((char *)dispose_command, command); + result = execute_command (command); + + run_unwind_frame ("command_builtin"); + + return (result); +} + +/* Restore the value of the $PATH variable after replacing it when + executing `command -p'. */ +static void +restore_path (var) + char *var; +{ + if (var) + { + bind_variable ("PATH", var, 0); + free (var); + } + else + unbind_variable ("PATH"); + + stupidly_hack_special_variables ("PATH"); +} + +/* Return a value for PATH that is guaranteed to find all of the standard + utilities. This uses Posix.2 configuration variables, if present. It + uses a value defined in config.h as a last resort. */ +static char * +get_standard_path () +{ +#if defined (_CS_PATH) && defined (HAVE_CONFSTR) + char *p; + size_t len; + + len = (size_t)confstr (_CS_PATH, (char *)NULL, (size_t)0); + if (len > 0) + { + p = (char *)xmalloc (len + 2); + *p = '\0'; + confstr (_CS_PATH, p, len); + return (p); + } + else + return (savestring (STANDARD_UTILS_PATH)); +#else /* !_CS_PATH || !HAVE_CONFSTR */ +# if defined (CS_PATH) + return (savestring (CS_PATH)); +# else + return (savestring (STANDARD_UTILS_PATH)); +# endif /* !CS_PATH */ +#endif /* !_CS_PATH || !HAVE_CONFSTR */ +} diff --git a/builtins/common.c b/builtins/common.c index ecd964e77..a6bbc33f4 100644 --- a/builtins/common.c +++ b/builtins/common.c @@ -176,9 +176,16 @@ int no_options (list) WORD_LIST *list; { + int opt; + reset_internal_getopt (); - if (internal_getopt (list, "") != -1) + if ((opt = internal_getopt (list, "")) != -1) { + if (opt == GETOPT_HELP) + { + builtin_help (); + return (2); + } builtin_usage (); return (1); } diff --git a/builtins/common.c~ b/builtins/common.c~ new file mode 100644 index 000000000..ecd964e77 --- /dev/null +++ b/builtins/common.c~ @@ -0,0 +1,901 @@ +/* common.c - utility functions for all builtins */ + +/* Copyright (C) 1987-2010 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 3 of the License, 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. If not, see . +*/ + +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include +#include +#include "../bashtypes.h" +#include "posixstat.h" +#include + +#include + +#if defined (PREFER_STDARG) +# include +#else +# include +#endif + +#include "../bashansi.h" +#include "../bashintl.h" + +#define NEED_FPURGE_DECL + +#include "../shell.h" +#include "maxpath.h" +#include "../flags.h" +#include "../jobs.h" +#include "../builtins.h" +#include "../input.h" +#include "../execute_cmd.h" +#include "../trap.h" +#include "bashgetopt.h" +#include "common.h" +#include "builtext.h" +#include + +#if defined (HISTORY) +# include "../bashhist.h" +#endif + +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +extern int indirection_level, subshell_environment; +extern int line_number; +extern int last_command_exit_value; +extern int trap_saved_exit_value; +extern int running_trap; +extern int posixly_correct; +extern char *this_command_name, *shell_name; +extern const char * const bash_getcwd_errstr; + +/* Used by some builtins and the mainline code. */ +sh_builtin_func_t *last_shell_builtin = (sh_builtin_func_t *)NULL; +sh_builtin_func_t *this_shell_builtin = (sh_builtin_func_t *)NULL; + +/* **************************************************************** */ +/* */ +/* Error reporting, usage, and option processing */ +/* */ +/* **************************************************************** */ + +/* This is a lot like report_error (), but it is for shell builtins + instead of shell control structures, and it won't ever exit the + shell. */ + +static void +builtin_error_prolog () +{ + char *name; + + name = get_name_for_error (); + fprintf (stderr, "%s: ", name); + + if (interactive_shell == 0) + fprintf (stderr, _("line %d: "), executing_line_number ()); + + if (this_command_name && *this_command_name) + fprintf (stderr, "%s: ", this_command_name); +} + +void +#if defined (PREFER_STDARG) +builtin_error (const char *format, ...) +#else +builtin_error (format, va_alist) + const char *format; + va_dcl +#endif +{ + va_list args; + + builtin_error_prolog (); + + SH_VA_START (args, format); + + vfprintf (stderr, format, args); + va_end (args); + fprintf (stderr, "\n"); +} + +void +#if defined (PREFER_STDARG) +builtin_warning (const char *format, ...) +#else +builtin_warning (format, va_alist) + const char *format; + va_dcl +#endif +{ + va_list args; + + builtin_error_prolog (); + fprintf (stderr, _("warning: ")); + + SH_VA_START (args, format); + + vfprintf (stderr, format, args); + va_end (args); + fprintf (stderr, "\n"); +} + +/* Print a usage summary for the currently-executing builtin command. */ +void +builtin_usage () +{ + if (this_command_name && *this_command_name) + fprintf (stderr, _("%s: usage: "), this_command_name); + fprintf (stderr, "%s\n", _(current_builtin->short_doc)); + fflush (stderr); +} + +/* Return if LIST is NULL else barf and jump to top_level. Used by some + builtins that do not accept arguments. */ +void +no_args (list) + WORD_LIST *list; +{ + if (list) + { + builtin_error (_("too many arguments")); + top_level_cleanup (); + jump_to_top_level (DISCARD); + } +} + +/* Check that no options were given to the currently-executing builtin, + and return 0 if there were options. */ +int +no_options (list) + WORD_LIST *list; +{ + reset_internal_getopt (); + if (internal_getopt (list, "") != -1) + { + builtin_usage (); + return (1); + } + return (0); +} + +void +sh_needarg (s) + char *s; +{ + builtin_error (_("%s: option requires an argument"), s); +} + +void +sh_neednumarg (s) + char *s; +{ + builtin_error (_("%s: numeric argument required"), s); +} + +void +sh_notfound (s) + char *s; +{ + builtin_error (_("%s: not found"), s); +} + +/* Function called when one of the builtin commands detects an invalid + option. */ +void +sh_invalidopt (s) + char *s; +{ + builtin_error (_("%s: invalid option"), s); +} + +void +sh_invalidoptname (s) + char *s; +{ + builtin_error (_("%s: invalid option name"), s); +} + +void +sh_invalidid (s) + char *s; +{ + builtin_error (_("`%s': not a valid identifier"), s); +} + +void +sh_invalidnum (s) + char *s; +{ + char *msg; + + if (*s == '0' && isdigit (s[1])) + msg = _("invalid octal number"); + else if (*s == '0' && s[1] == 'x') + msg = _("invalid hex number"); + else + msg = _("invalid number"); + builtin_error ("%s: %s", s, msg); +} + +void +sh_invalidsig (s) + char *s; +{ + builtin_error (_("%s: invalid signal specification"), s); +} + +void +sh_badpid (s) + char *s; +{ + builtin_error (_("`%s': not a pid or valid job spec"), s); +} + +void +sh_readonly (s) + const char *s; +{ + builtin_error (_("%s: readonly variable"), s); +} + +void +sh_erange (s, desc) + char *s, *desc; +{ + if (s) + builtin_error (_("%s: %s out of range"), s, desc ? desc : _("argument")); + else + builtin_error (_("%s out of range"), desc ? desc : _("argument")); +} + +#if defined (JOB_CONTROL) +void +sh_badjob (s) + char *s; +{ + builtin_error (_("%s: no such job"), s); +} + +void +sh_nojobs (s) + char *s; +{ + if (s) + builtin_error (_("%s: no job control"), s); + else + builtin_error (_("no job control")); +} +#endif + +#if defined (RESTRICTED_SHELL) +void +sh_restricted (s) + char *s; +{ + if (s) + builtin_error (_("%s: restricted"), s); + else + builtin_error (_("restricted")); +} +#endif + +void +sh_notbuiltin (s) + char *s; +{ + builtin_error (_("%s: not a shell builtin"), s); +} + +void +sh_wrerror () +{ +#if defined (DONT_REPORT_BROKEN_PIPE_WRITE_ERRORS) && defined (EPIPE) + if (errno != EPIPE) +#endif /* DONT_REPORT_BROKEN_PIPE_WRITE_ERRORS && EPIPE */ + builtin_error (_("write error: %s"), strerror (errno)); +} + +void +sh_ttyerror (set) + int set; +{ + if (set) + builtin_error (_("error setting terminal attributes: %s"), strerror (errno)); + else + builtin_error (_("error getting terminal attributes: %s"), strerror (errno)); +} + +int +sh_chkwrite (s) + int s; +{ + fflush (stdout); + if (ferror (stdout)) + { + sh_wrerror (); + fpurge (stdout); + clearerr (stdout); + return (EXECUTION_FAILURE); + } + return (s); +} + +/* **************************************************************** */ +/* */ +/* Shell positional parameter manipulation */ +/* */ +/* **************************************************************** */ + +/* Convert a WORD_LIST into a C-style argv. Return the number of elements + in the list in *IP, if IP is non-null. A convenience function for + loadable builtins; also used by `test'. */ +char ** +make_builtin_argv (list, ip) + WORD_LIST *list; + int *ip; +{ + char **argv; + + argv = strvec_from_word_list (list, 0, 1, ip); + argv[0] = this_command_name; + return argv; +} + +/* Remember LIST in $1 ... $9, and REST_OF_ARGS. If DESTRUCTIVE is + non-zero, then discard whatever the existing arguments are, else + only discard the ones that are to be replaced. */ +void +remember_args (list, destructive) + WORD_LIST *list; + int destructive; +{ + register int i; + + for (i = 1; i < 10; i++) + { + if ((destructive || list) && dollar_vars[i]) + { + free (dollar_vars[i]); + dollar_vars[i] = (char *)NULL; + } + + if (list) + { + dollar_vars[i] = savestring (list->word->word); + list = list->next; + } + } + + /* If arguments remain, assign them to REST_OF_ARGS. + Note that copy_word_list (NULL) returns NULL, and + that dispose_words (NULL) does nothing. */ + if (destructive || list) + { + dispose_words (rest_of_args); + rest_of_args = copy_word_list (list); + } + + if (destructive) + set_dollar_vars_changed (); +} + +static int changed_dollar_vars; + +/* Have the dollar variables been reset to new values since we last + checked? */ +int +dollar_vars_changed () +{ + return (changed_dollar_vars); +} + +void +set_dollar_vars_unchanged () +{ + changed_dollar_vars = 0; +} + +void +set_dollar_vars_changed () +{ + if (variable_context) + changed_dollar_vars |= ARGS_FUNC; + else if (this_shell_builtin == set_builtin) + changed_dollar_vars |= ARGS_SETBLTIN; + else + changed_dollar_vars |= ARGS_INVOC; +} + +/* **************************************************************** */ +/* */ +/* Validating numeric input and arguments */ +/* */ +/* **************************************************************** */ + +/* Read a numeric arg for this_command_name, the name of the shell builtin + that wants it. LIST is the word list that the arg is to come from. + Accept only the numeric argument; report an error if other arguments + follow. If FATAL is 1, call throw_to_top_level, which exits the + shell; if it's 2, call jump_to_top_level (DISCARD), which aborts the + current command; if FATAL is 0, return an indication of an invalid + number by setting *NUMOK == 0 and return -1. */ +int +get_numeric_arg (list, fatal, count) + WORD_LIST *list; + int fatal; + intmax_t *count; +{ + char *arg; + + if (count) + *count = 1; + + if (list && list->word && ISOPTION (list->word->word, '-')) + list = list->next; + + if (list) + { + arg = list->word->word; + if (arg == 0 || (legal_number (arg, count) == 0)) + { + sh_neednumarg (list->word->word ? list->word->word : "`'"); + if (fatal == 0) + return 0; + else if (fatal == 1) /* fatal == 1; abort */ + throw_to_top_level (); + else /* fatal == 2; discard current command */ + { + top_level_cleanup (); + jump_to_top_level (DISCARD); + } + } + no_args (list->next); + } + + return (1); +} + +/* Get an eight-bit status value from LIST */ +int +get_exitstat (list) + WORD_LIST *list; +{ + int status; + intmax_t sval; + char *arg; + + if (list && list->word && ISOPTION (list->word->word, '-')) + list = list->next; + + if (list == 0) + { + /* If we're not running the DEBUG trap, the return builtin, when not + given any arguments, uses the value of $? before the trap ran. If + given an argument, return uses it. This means that the trap can't + change $?. The DEBUG trap gets to change $?, though, since that is + part of its reason for existing, and because the extended debug mode + does things with the return value. */ + if (this_shell_builtin == return_builtin && running_trap > 0 && running_trap != DEBUG_TRAP+1) + return (trap_saved_exit_value); + return (last_command_exit_value); + } + + arg = list->word->word; + if (arg == 0 || legal_number (arg, &sval) == 0) + { + sh_neednumarg (list->word->word ? list->word->word : "`'"); + return EX_BADUSAGE; + } + no_args (list->next); + + status = sval & 255; + return status; +} + +/* Return the octal number parsed from STRING, or -1 to indicate + that the string contained a bad number. */ +int +read_octal (string) + char *string; +{ + int result, digits; + + result = digits = 0; + while (*string && ISOCTAL (*string)) + { + digits++; + result = (result * 8) + (*string++ - '0'); + if (result > 0777) + return -1; + } + + if (digits == 0 || *string) + result = -1; + + return (result); +} + +/* **************************************************************** */ +/* */ +/* Manipulating the current working directory */ +/* */ +/* **************************************************************** */ + +/* Return a consed string which is the current working directory. + FOR_WHOM is the name of the caller for error printing. */ +char *the_current_working_directory = (char *)NULL; + +char * +get_working_directory (for_whom) + char *for_whom; +{ + if (no_symbolic_links) + { + FREE (the_current_working_directory); + the_current_working_directory = (char *)NULL; + } + + if (the_current_working_directory == 0) + { +#if defined (GETCWD_BROKEN) + the_current_working_directory = getcwd (0, PATH_MAX); +#else + the_current_working_directory = getcwd (0, 0); +#endif + if (the_current_working_directory == 0) + { + fprintf (stderr, _("%s: error retrieving current directory: %s: %s\n"), + (for_whom && *for_whom) ? for_whom : get_name_for_error (), + _(bash_getcwd_errstr), strerror (errno)); + return (char *)NULL; + } + } + + return (savestring (the_current_working_directory)); +} + +/* Make NAME our internal idea of the current working directory. */ +void +set_working_directory (name) + char *name; +{ + FREE (the_current_working_directory); + the_current_working_directory = savestring (name); +} + +/* **************************************************************** */ +/* */ +/* Job control support functions */ +/* */ +/* **************************************************************** */ + +#if defined (JOB_CONTROL) +int +get_job_by_name (name, flags) + const char *name; + int flags; +{ + register int i, wl, cl, match, job; + register PROCESS *p; + register JOB *j; + + job = NO_JOB; + wl = strlen (name); + for (i = js.j_jobslots - 1; i >= 0; i--) + { + j = get_job_by_jid (i); + if (j == 0 || ((flags & JM_STOPPED) && J_JOBSTATE(j) != JSTOPPED)) + continue; + + p = j->pipe; + do + { + if (flags & JM_EXACT) + { + cl = strlen (p->command); + match = STREQN (p->command, name, cl); + } + else if (flags & JM_SUBSTRING) + match = strcasestr (p->command, name) != (char *)0; + else + match = STREQN (p->command, name, wl); + + if (match == 0) + { + p = p->next; + continue; + } + else if (flags & JM_FIRSTMATCH) + return i; /* return first match */ + else if (job != NO_JOB) + { + if (this_shell_builtin) + builtin_error (_("%s: ambiguous job spec"), name); + else + internal_error (_("%s: ambiguous job spec"), name); + return (DUP_JOB); + } + else + job = i; + } + while (p != j->pipe); + } + + return (job); +} + +/* Return the job spec found in LIST. */ +int +get_job_spec (list) + WORD_LIST *list; +{ + register char *word; + int job, jflags; + + if (list == 0) + return (js.j_current); + + word = list->word->word; + + if (*word == '\0') + return (NO_JOB); + + if (*word == '%') + word++; + + if (DIGIT (*word) && all_digits (word)) + { + job = atoi (word); + return (job > js.j_jobslots ? NO_JOB : job - 1); + } + + jflags = 0; + switch (*word) + { + case 0: + case '%': + case '+': + return (js.j_current); + + case '-': + return (js.j_previous); + + case '?': /* Substring search requested. */ + jflags |= JM_SUBSTRING; + word++; + /* FALLTHROUGH */ + + default: + return get_job_by_name (word, jflags); + } +} +#endif /* JOB_CONTROL */ + +/* + * NOTE: `kill' calls this function with forcecols == 0 + */ +int +display_signal_list (list, forcecols) + WORD_LIST *list; + int forcecols; +{ + register int i, column; + char *name; + int result, signum, dflags; + intmax_t lsignum; + + result = EXECUTION_SUCCESS; + if (!list) + { + for (i = 1, column = 0; i < NSIG; i++) + { + name = signal_name (i); + if (STREQN (name, "SIGJUNK", 7) || STREQN (name, "Unknown", 7)) + continue; + + if (posixly_correct && !forcecols) + { + /* This is for the kill builtin. POSIX.2 says the signal names + are displayed without the `SIG' prefix. */ + if (STREQN (name, "SIG", 3)) + name += 3; + printf ("%s%s", name, (i == NSIG - 1) ? "" : " "); + } + else + { + printf ("%2d) %s", i, name); + + if (++column < 5) + printf ("\t"); + else + { + printf ("\n"); + column = 0; + } + } + } + + if ((posixly_correct && !forcecols) || column != 0) + printf ("\n"); + return result; + } + + /* List individual signal names or numbers. */ + while (list) + { + if (legal_number (list->word->word, &lsignum)) + { + /* This is specified by Posix.2 so that exit statuses can be + mapped into signal numbers. */ + if (lsignum > 128) + lsignum -= 128; + if (lsignum < 0 || lsignum >= NSIG) + { + sh_invalidsig (list->word->word); + result = EXECUTION_FAILURE; + list = list->next; + continue; + } + + signum = lsignum; + name = signal_name (signum); + if (STREQN (name, "SIGJUNK", 7) || STREQN (name, "Unknown", 7)) + { + list = list->next; + continue; + } +#if defined (JOB_CONTROL) + /* POSIX.2 says that `kill -l signum' prints the signal name without + the `SIG' prefix. */ + printf ("%s\n", (this_shell_builtin == kill_builtin) ? name + 3 : name); +#else + printf ("%s\n", name); +#endif + } + else + { + dflags = DSIG_NOCASE; + if (posixly_correct == 0 || this_shell_builtin != kill_builtin) + dflags |= DSIG_SIGPREFIX; + signum = decode_signal (list->word->word, dflags); + if (signum == NO_SIG) + { + sh_invalidsig (list->word->word); + result = EXECUTION_FAILURE; + list = list->next; + continue; + } + printf ("%d\n", signum); + } + list = list->next; + } + return (result); +} + +/* **************************************************************** */ +/* */ +/* Finding builtin commands and their functions */ +/* */ +/* **************************************************************** */ + +/* Perform a binary search and return the address of the builtin function + whose name is NAME. If the function couldn't be found, or the builtin + is disabled or has no function associated with it, return NULL. + Return the address of the builtin. + DISABLED_OKAY means find it even if the builtin is disabled. */ +struct builtin * +builtin_address_internal (name, disabled_okay) + char *name; + int disabled_okay; +{ + int hi, lo, mid, j; + + hi = num_shell_builtins - 1; + lo = 0; + + while (lo <= hi) + { + mid = (lo + hi) / 2; + + j = shell_builtins[mid].name[0] - name[0]; + + if (j == 0) + j = strcmp (shell_builtins[mid].name, name); + + if (j == 0) + { + /* It must have a function pointer. It must be enabled, or we + must have explicitly allowed disabled functions to be found, + and it must not have been deleted. */ + if (shell_builtins[mid].function && + ((shell_builtins[mid].flags & BUILTIN_DELETED) == 0) && + ((shell_builtins[mid].flags & BUILTIN_ENABLED) || disabled_okay)) + return (&shell_builtins[mid]); + else + return ((struct builtin *)NULL); + } + if (j > 0) + hi = mid - 1; + else + lo = mid + 1; + } + return ((struct builtin *)NULL); +} + +/* Return the pointer to the function implementing builtin command NAME. */ +sh_builtin_func_t * +find_shell_builtin (name) + char *name; +{ + current_builtin = builtin_address_internal (name, 0); + return (current_builtin ? current_builtin->function : (sh_builtin_func_t *)NULL); +} + +/* Return the address of builtin with NAME, whether it is enabled or not. */ +sh_builtin_func_t * +builtin_address (name) + char *name; +{ + current_builtin = builtin_address_internal (name, 1); + return (current_builtin ? current_builtin->function : (sh_builtin_func_t *)NULL); +} + +/* Return the function implementing the builtin NAME, but only if it is a + POSIX.2 special builtin. */ +sh_builtin_func_t * +find_special_builtin (name) + char *name; +{ + current_builtin = builtin_address_internal (name, 0); + return ((current_builtin && (current_builtin->flags & SPECIAL_BUILTIN)) ? + current_builtin->function : + (sh_builtin_func_t *)NULL); +} + +static int +shell_builtin_compare (sbp1, sbp2) + struct builtin *sbp1, *sbp2; +{ + int result; + + if ((result = sbp1->name[0] - sbp2->name[0]) == 0) + result = strcmp (sbp1->name, sbp2->name); + + return (result); +} + +/* Sort the table of shell builtins so that the binary search will work + in find_shell_builtin. */ +void +initialize_shell_builtins () +{ + qsort (shell_builtins, num_shell_builtins, sizeof (struct builtin), + (QSFUNC *)shell_builtin_compare); +} diff --git a/builtins/common.h b/builtins/common.h index b0c2f7db1..369472e48 100644 --- a/builtins/common.h +++ b/builtins/common.h @@ -24,6 +24,21 @@ #include "stdc.h" #define ISOPTION(s, c) (s[0] == '-' && !s[2] && s[1] == c) +#define ISHELP(s) (STREQ ((s), "--help")) + +#define CHECK_HELPOPT(l) \ +do { \ + if ((l) && (l)->word && ISHELP((l)->word->word)) \ + { \ + builtin_help (); \ + return (EX_USAGE); \ + } \ +} while (0) + +#define CASE_HELPOPT() \ + case GETOPT_HELP: \ + builtin_help (); \ + return (EX_USAGE) /* Flag values for parse_and_execute () */ #define SEVAL_NONINT 0x001 @@ -120,6 +135,9 @@ extern void bash_logout __P((void)); /* Functions from getopts.def */ extern void getopts_reset __P((int)); +/* Functions from help.def */ +extern void builtin_help __P((void)); + /* Functions from set.def */ extern int minus_o_option_value __P((char *)); extern void list_minus_o_opts __P((int, int)); diff --git a/builtins/common.h~ b/builtins/common.h~ new file mode 100644 index 000000000..0b3d57ca3 --- /dev/null +++ b/builtins/common.h~ @@ -0,0 +1,191 @@ +/* common.h -- extern declarations for functions defined in common.c. */ + +/* Copyright (C) 1993-2010 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 3 of the License, 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. If not, see . +*/ + +#if !defined (__COMMON_H) +# define __COMMON_H + +#include "stdc.h" + +#define ISOPTION(s, c) (s[0] == '-' && !s[2] && s[1] == c) +#define ISHELP(s) (STREQ ((s), "--help")) + +#define CHECK_HELPOPT(l) \ +do { \ + if ((l) && (l)->word && ISHELP((l)->word->word)) \ + { \ + builtin_help (); \ + return (EX_USAGE); \ + } \ +} while (0) + +/* Flag values for parse_and_execute () */ +#define SEVAL_NONINT 0x001 +#define SEVAL_INTERACT 0x002 +#define SEVAL_NOHIST 0x004 +#define SEVAL_NOFREE 0x008 +#define SEVAL_RESETLINE 0x010 +#define SEVAL_PARSEONLY 0x020 +#define SEVAL_NOLONGJMP 0x040 + +/* Flags for describe_command, shared between type.def and command.def */ +#define CDESC_ALL 0x001 /* type -a */ +#define CDESC_SHORTDESC 0x002 /* command -V */ +#define CDESC_REUSABLE 0x004 /* command -v */ +#define CDESC_TYPE 0x008 /* type -t */ +#define CDESC_PATH_ONLY 0x010 /* type -p */ +#define CDESC_FORCE_PATH 0x020 /* type -ap or type -P */ +#define CDESC_NOFUNCS 0x040 /* type -f */ +#define CDESC_ABSPATH 0x080 /* convert to absolute path, no ./ */ + +/* Flags for get_job_by_name */ +#define JM_PREFIX 0x01 /* prefix of job name */ +#define JM_SUBSTRING 0x02 /* substring of job name */ +#define JM_EXACT 0x04 /* match job name exactly */ +#define JM_STOPPED 0x08 /* match stopped jobs only */ +#define JM_FIRSTMATCH 0x10 /* return first matching job */ + +/* Flags for remember_args and value of changed_dollar_vars */ +#define ARGS_NONE 0x0 +#define ARGS_INVOC 0x01 +#define ARGS_FUNC 0x02 +#define ARGS_SETBLTIN 0x04 + +/* Functions from common.c */ +extern void builtin_error __P((const char *, ...)) __attribute__((__format__ (printf, 1, 2))); +extern void builtin_warning __P((const char *, ...)) __attribute__((__format__ (printf, 1, 2))); +extern void builtin_usage __P((void)); +extern void no_args __P((WORD_LIST *)); +extern int no_options __P((WORD_LIST *)); + +/* common error message functions */ +extern void sh_needarg __P((char *)); +extern void sh_neednumarg __P((char *)); +extern void sh_notfound __P((char *)); +extern void sh_invalidopt __P((char *)); +extern void sh_invalidoptname __P((char *)); +extern void sh_invalidid __P((char *)); +extern void sh_invalidnum __P((char *)); +extern void sh_invalidsig __P((char *)); +extern void sh_erange __P((char *, char *)); +extern void sh_badpid __P((char *)); +extern void sh_badjob __P((char *)); +extern void sh_readonly __P((const char *)); +extern void sh_nojobs __P((char *)); +extern void sh_restricted __P((char *)); +extern void sh_notbuiltin __P((char *)); +extern void sh_wrerror __P((void)); +extern void sh_ttyerror __P((int)); +extern int sh_chkwrite __P((int)); + +extern char **make_builtin_argv __P((WORD_LIST *, int *)); +extern void remember_args __P((WORD_LIST *, int)); + +extern int dollar_vars_changed __P((void)); +extern void set_dollar_vars_unchanged __P((void)); +extern void set_dollar_vars_changed __P((void)); + +extern int get_numeric_arg __P((WORD_LIST *, int, intmax_t *)); +extern int get_exitstat __P((WORD_LIST *)); +extern int read_octal __P((char *)); + +/* Keeps track of the current working directory. */ +extern char *the_current_working_directory; +extern char *get_working_directory __P((char *)); +extern void set_working_directory __P((char *)); + +#if defined (JOB_CONTROL) +extern int get_job_by_name __P((const char *, int)); +extern int get_job_spec __P((WORD_LIST *)); +#endif +extern int display_signal_list __P((WORD_LIST *, int)); + +/* It's OK to declare a function as returning a Function * without + providing a definition of what a `Function' is. */ +extern struct builtin *builtin_address_internal __P((char *, int)); +extern sh_builtin_func_t *find_shell_builtin __P((char *)); +extern sh_builtin_func_t *builtin_address __P((char *)); +extern sh_builtin_func_t *find_special_builtin __P((char *)); +extern void initialize_shell_builtins __P((void)); + +/* Functions from exit.def */ +extern void bash_logout __P((void)); + +/* Functions from getopts.def */ +extern void getopts_reset __P((int)); + +/* Functions from help.def */ +extern void builtin_help __P((void)); + +/* Functions from set.def */ +extern int minus_o_option_value __P((char *)); +extern void list_minus_o_opts __P((int, int)); +extern char **get_minus_o_opts __P((void)); +extern int set_minus_o_option __P((int, char *)); + +extern void set_shellopts __P((void)); +extern void parse_shellopts __P((char *)); +extern void initialize_shell_options __P((int)); + +extern void reset_shell_options __P((void)); + +/* Functions from shopt.def */ +extern void reset_shopt_options __P((void)); +extern char **get_shopt_options __P((void)); + +extern int shopt_setopt __P((char *, int)); +extern int shopt_listopt __P((char *, int)); + +extern int set_login_shell __P((char *, int)); + +extern void set_bashopts __P((void)); +extern void parse_bashopts __P((char *)); +extern void initialize_bashopts __P((int)); + +extern void set_compatibility_opts __P((void)); + +/* Functions from type.def */ +extern int describe_command __P((char *, int)); + +/* Functions from setattr.def */ +extern int set_or_show_attributes __P((WORD_LIST *, int, int)); +extern int show_all_var_attributes __P((int, int)); +extern int show_var_attributes __P((SHELL_VAR *, int, int)); +extern int show_name_attributes __P((char *, int)); +extern int show_func_attributes __P((char *, int)); +extern void set_var_attribute __P((char *, int, int)); + +/* Functions from pushd.def */ +extern char *get_dirstack_from_string __P((char *)); +extern char *get_dirstack_element __P((intmax_t, int)); +extern void set_dirstack_element __P((intmax_t, int, char *)); +extern WORD_LIST *get_directory_stack __P((int)); + +/* Functions from evalstring.c */ +extern int parse_and_execute __P((char *, const char *, int)); +extern int evalstring __P((char *, const char *, int)); +extern void parse_and_execute_cleanup __P((void)); +extern int parse_string __P((char *, const char *, int, char **)); + +/* Functions from evalfile.c */ +extern int maybe_execute_file __P((const char *, int)); +extern int source_file __P((const char *, int)); +extern int fc_execute_file __P((const char *)); + +#endif /* !__COMMON_H */ diff --git a/builtins/complete.def b/builtins/complete.def index 0a97dfb3f..0a292ac7a 100644 --- a/builtins/complete.def +++ b/builtins/complete.def @@ -1,7 +1,7 @@ This file is complete.def, from which is created complete.c. It implements the builtins "complete", "compgen", and "compopt" in Bash. -Copyright (C) 1999-2011 Free Software Foundation, Inc. +Copyright (C) 1999-2014 Free Software Foundation, Inc. This file is part of GNU Bash, the Bourne Again SHell. @@ -790,7 +790,7 @@ compopt_builtin (list) ret = EXECUTION_SUCCESS; reset_internal_getopt (); - while ((opt = internal_getopt (list, "+o:DE")) != EOF) + while ((opt = internal_getopt (list, "+o:DE")) != -1) { opts = (list_opttype == '-') ? &opts_on : &opts_off; diff --git a/builtins/declare.def b/builtins/declare.def index f69daf8ae..c80d6f2fa 100644 --- a/builtins/declare.def +++ b/builtins/declare.def @@ -1,7 +1,7 @@ This file is declare.def, from which is created declare.c. It implements the builtins "declare" and "local" in Bash. -Copyright (C) 1987-2012 Free Software Foundation, Inc. +Copyright (C) 1987-2014 Free Software Foundation, Inc. This file is part of GNU Bash, the Bourne Again SHell. @@ -150,7 +150,7 @@ declare_internal (list, local_var) flags_on = flags_off = any_failed = assign_error = pflag = nodefs = mkglobal = 0; refvar = (SHELL_VAR *)NULL; reset_internal_getopt (); - while ((opt = internal_getopt (list, DECLARE_OPTS)) != EOF) + while ((opt = internal_getopt (list, DECLARE_OPTS)) != -1) { flags = list_opttype == '+' ? &flags_off : &flags_on; diff --git a/builtins/exit.def b/builtins/exit.def index 34728ebfa..f28c2342c 100644 --- a/builtins/exit.def +++ b/builtins/exit.def @@ -60,6 +60,8 @@ int exit_builtin (list) WORD_LIST *list; { + CHECK_HELPOPT (list); + if (interactive) { fprintf (stderr, login_shell ? _("logout\n") : "exit\n"); @@ -83,6 +85,8 @@ int logout_builtin (list) WORD_LIST *list; { + CHECK_HELPOPT (list); + if (login_shell == 0 /* && interactive */) { builtin_error (_("not login shell: use `exit'")); diff --git a/builtins/exit.def~ b/builtins/exit.def~ new file mode 100644 index 000000000..34728ebfa --- /dev/null +++ b/builtins/exit.def~ @@ -0,0 +1,168 @@ +This file is exit.def, from which is created exit.c. +It implements the builtins "exit", and "logout" in Bash. + +Copyright (C) 1987-2009 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 3 of the License, 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. If not, see . + +$PRODUCES exit.c + +$BUILTIN exit +$FUNCTION exit_builtin +$SHORT_DOC exit [n] +Exit the shell. + +Exits the shell with a status of N. If N is omitted, the exit status +is that of the last command executed. +$END + +#include + +#include "../bashtypes.h" +#include + +#if defined (HAVE_UNISTD_H) +# include +#endif + +#include "../bashintl.h" + +#include "../shell.h" +#include "../jobs.h" + +#include "common.h" +#include "builtext.h" /* for jobs_builtin */ + +extern int check_jobs_at_exit; +extern int last_command_exit_value; +extern int running_trap, trap_saved_exit_value; +extern int subshell_environment; +extern sh_builtin_func_t *this_shell_builtin; +extern sh_builtin_func_t *last_shell_builtin; + +static int exit_or_logout __P((WORD_LIST *)); +static int sourced_logout; + +int +exit_builtin (list) + WORD_LIST *list; +{ + if (interactive) + { + fprintf (stderr, login_shell ? _("logout\n") : "exit\n"); + fflush (stderr); + } + + return (exit_or_logout (list)); +} + +$BUILTIN logout +$FUNCTION logout_builtin +$SHORT_DOC logout [n] +Exit a login shell. + +Exits a login shell with exit status N. Returns an error if not executed +in a login shell. +$END + +/* How to logout. */ +int +logout_builtin (list) + WORD_LIST *list; +{ + if (login_shell == 0 /* && interactive */) + { + builtin_error (_("not login shell: use `exit'")); + return (EXECUTION_FAILURE); + } + else + return (exit_or_logout (list)); +} + +static int +exit_or_logout (list) + WORD_LIST *list; +{ + int exit_value; + +#if defined (JOB_CONTROL) + int exit_immediate_okay, stopmsg; + + exit_immediate_okay = (interactive == 0 || + last_shell_builtin == exit_builtin || + last_shell_builtin == logout_builtin || + last_shell_builtin == jobs_builtin); + + /* Check for stopped jobs if the user wants to. */ + if (exit_immediate_okay == 0) + { + register int i; + for (i = stopmsg = 0; i < js.j_jobslots; i++) + if (jobs[i] && STOPPED (i)) + stopmsg = JSTOPPED; + else if (check_jobs_at_exit && stopmsg == 0 && jobs[i] && RUNNING (i)) + stopmsg = JRUNNING; + + if (stopmsg == JSTOPPED) + fprintf (stderr, _("There are stopped jobs.\n")); + else if (stopmsg == JRUNNING) + fprintf (stderr, _("There are running jobs.\n")); + + if (stopmsg && check_jobs_at_exit) + list_all_jobs (JLIST_STANDARD); + + if (stopmsg) + { + /* This is NOT superfluous because EOF can get here without + going through the command parser. Set both last and this + so that either `exit', `logout', or ^D will work to exit + immediately if nothing intervenes. */ + this_shell_builtin = last_shell_builtin = exit_builtin; + return (EXECUTION_FAILURE); + } + } +#endif /* JOB_CONTROL */ + + /* Get return value if present. This means that you can type + `logout 5' to a shell, and it returns 5. */ + + /* If we're running the exit trap (running_trap == 1, since running_trap + gets set to SIG+1), and we don't have a argument given to `exit' + (list == 0), use the exit status we saved before running the trap + commands (trap_saved_exit_value). */ + exit_value = (running_trap == 1 && list == 0) ? trap_saved_exit_value : get_exitstat (list); + + bash_logout (); + + last_command_exit_value = exit_value; + + /* Exit the program. */ + jump_to_top_level (EXITPROG); + /*NOTREACHED*/ +} + +void +bash_logout () +{ + /* Run our `~/.bash_logout' file if it exists, and this is a login shell. */ + if (login_shell && sourced_logout++ == 0 && subshell_environment == 0) + { + maybe_execute_file ("~/.bash_logout", 1); +#ifdef SYS_BASH_LOGOUT + maybe_execute_file (SYS_BASH_LOGOUT, 1); +#endif + } +} diff --git a/builtins/fg_bg.def b/builtins/fg_bg.def index ae7e90402..1565e0a12 100644 --- a/builtins/fg_bg.def +++ b/builtins/fg_bg.def @@ -63,6 +63,8 @@ fg_builtin (list) int fg_bit; register WORD_LIST *t; + CHECK_HELPOPT (list); + if (job_control == 0) { sh_nojobs ((char *)NULL); @@ -105,6 +107,8 @@ bg_builtin (list) { int r; + CHECK_HELPOPT (list); + if (job_control == 0) { sh_nojobs ((char *)NULL); diff --git a/builtins/fg_bg.def~ b/builtins/fg_bg.def~ new file mode 100644 index 000000000..86ab4d6f3 --- /dev/null +++ b/builtins/fg_bg.def~ @@ -0,0 +1,194 @@ +This file is fg_bg.def, from which is created fg_bg.c. +It implements the builtins "bg" and "fg" in Bash. + +Copyright (C) 1987-2009 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 3 of the License, 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. If not, see . + +$PRODUCES fg_bg.c + +$BUILTIN fg +$FUNCTION fg_builtin +$DEPENDS_ON JOB_CONTROL +$SHORT_DOC fg [job_spec] +Move job to the foreground. + +Place the job identified by JOB_SPEC in the foreground, making it the +current job. If JOB_SPEC is not present, the shell's notion of the +current job is used. + +Exit Status: +Status of command placed in foreground, or failure if an error occurs. +$END + +#include + +#include "../bashtypes.h" +#include + +#if defined (HAVE_UNISTD_H) +# include +#endif + +#include "../bashintl.h" + +#include "../shell.h" +#include "../jobs.h" +#include "common.h" +#include "bashgetopt.h" + +#if defined (JOB_CONTROL) +extern char *this_command_name; + +static int fg_bg __P((WORD_LIST *, int)); + +/* How to bring a job into the foreground. */ +int +fg_builtin (list) + WORD_LIST *list; +{ + int fg_bit; + register WORD_LIST *t; + + CHECK_HELPOPT (list); + + if (job_control == 0) + { + sh_nojobs ((char *)NULL); + return (EXECUTION_FAILURE); + } + + if (no_options (list)) + return (EX_USAGE); + list = loptend; + + /* If the last arg on the line is '&', then start this job in the + background. Else, fg the job. */ + for (t = list; t && t->next; t = t->next) + ; + fg_bit = (t && t->word->word[0] == '&' && t->word->word[1] == '\0') == 0; + + return (fg_bg (list, fg_bit)); +} +#endif /* JOB_CONTROL */ + +$BUILTIN bg +$FUNCTION bg_builtin +$DEPENDS_ON JOB_CONTROL +$SHORT_DOC bg [job_spec ...] +Move jobs to the background. + +Place the jobs identified by each JOB_SPEC in the background, as if they +had been started with `&'. If JOB_SPEC is not present, the shell's notion +of the current job is used. + +Exit Status: +Returns success unless job control is not enabled or an error occurs. +$END + +#if defined (JOB_CONTROL) +/* How to put a job into the background. */ +int +bg_builtin (list) + WORD_LIST *list; +{ + int r; + + if (list && list->word && ISHELP (list->word->word)) + { + builtin_help (); + return (EX_USAGE); + } + + if (job_control == 0) + { + sh_nojobs ((char *)NULL); + return (EXECUTION_FAILURE); + } + + if (no_options (list)) + return (EX_USAGE); + list = loptend; + + /* This relies on the fact that fg_bg() takes a WORD_LIST *, but only acts + on the first member (if any) of that list. */ + r = EXECUTION_SUCCESS; + do + { + if (fg_bg (list, 0) == EXECUTION_FAILURE) + r = EXECUTION_FAILURE; + if (list) + list = list->next; + } + while (list); + + return r; +} + +/* How to put a job into the foreground/background. */ +static int +fg_bg (list, foreground) + WORD_LIST *list; + int foreground; +{ + sigset_t set, oset; + int job, status, old_async_pid; + JOB *j; + + BLOCK_CHILD (set, oset); + job = get_job_spec (list); + + if (INVALID_JOB (job)) + { + if (job != DUP_JOB) + sh_badjob (list ? list->word->word : _("current")); + + goto failure; + } + + j = get_job_by_jid (job); + /* Or if j->pgrp == shell_pgrp. */ + if (IS_JOBCONTROL (job) == 0) + { + builtin_error (_("job %d started without job control"), job + 1); + goto failure; + } + + if (foreground == 0) + { + old_async_pid = last_asynchronous_pid; + last_asynchronous_pid = j->pgrp; /* As per Posix.2 5.4.2 */ + } + + status = start_job (job, foreground); + + if (status >= 0) + { + /* win: */ + UNBLOCK_CHILD (oset); + return (foreground ? status : EXECUTION_SUCCESS); + } + else + { + if (foreground == 0) + last_asynchronous_pid = old_async_pid; + + failure: + UNBLOCK_CHILD (oset); + return (EXECUTION_FAILURE); + } +} +#endif /* JOB_CONTROL */ diff --git a/builtins/getopt.h~ b/builtins/getopt.h~ new file mode 100644 index 000000000..f657039a7 --- /dev/null +++ b/builtins/getopt.h~ @@ -0,0 +1,68 @@ +/* getopt.h - declarations for getopt. */ + +/* Copyright (C) 1989, 1990, 1991, 1992, 1993, 2008,2009 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 3 of the License, 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. If not, see . +*/ + +/* XXX THIS HAS BEEN MODIFIED FOR INCORPORATION INTO BASH XXX */ + +#ifndef _SH_GETOPT_H +#define _SH_GETOPT_H 1 + +#include "stdc.h" + +#define GETOPT_EOF -1 +#define GETOPT_HELP -99 + +/* For communication from `getopt' to the caller. + When `getopt' finds an option that takes an argument, + the argument value is returned here. + Also, when `ordering' is RETURN_IN_ORDER, + each non-option ARGV-element is returned here. */ + +extern char *sh_optarg; + +/* Index in ARGV of the next element to be scanned. + This is used for communication to and from the caller + and for communication between successive calls to `getopt'. + + On entry to `getopt', zero means this is the first call; initialize. + + When `getopt' returns EOF, this is the index of the first of the + non-option elements that the caller should itself scan. + + Otherwise, `sh_optind' communicates from one call to the next + how much of ARGV has been scanned so far. */ + +extern int sh_optind; + +/* Callers store zero here to inhibit the error message `getopt' prints + for unrecognized options. */ + +extern int sh_opterr; + +/* Set to an option character which was unrecognized. */ + +extern int sh_optopt; + +/* Set to 1 when an unrecognized option is encountered. */ +extern int sh_badopt; + +extern int sh_getopt __P((int, char *const *, const char *)); +extern void sh_getopt_restore_state __P((char **)); + +#endif /* _SH_GETOPT_H */ diff --git a/builtins/help.def b/builtins/help.def index 1b4f85141..ef20c7b44 100644 --- a/builtins/help.def +++ b/builtins/help.def @@ -58,6 +58,7 @@ $END #include #include +#include #include "../bashintl.h" @@ -77,6 +78,9 @@ extern int errno; extern const char * const bash_copyright; extern const char * const bash_license; +extern char *this_command_name; +extern struct builtin *current_builtin; + static void show_builtin_command_help __P((void)); static int open_helpfile __P((char *)); static void show_desc __P((char *, int)); @@ -187,6 +191,28 @@ help_builtin (list) return (EXECUTION_SUCCESS); } +void +builtin_help () +{ + int ind; + ptrdiff_t d; + + current_builtin = builtin_address_internal (this_command_name, 0); + if (current_builtin == 0) + return; + + d = current_builtin - shell_builtins; + +#if defined (__STDC__) + ind = (int)d; +#else + ind = (int)d / sizeof (struct builtin); +#endif + + printf ("%s: %s\n", this_command_name, _(shell_builtins[ind].short_doc)); + show_longdoc (ind); +} + static int open_helpfile (name) char *name; diff --git a/builtins/help.def~ b/builtins/help.def~ new file mode 100644 index 000000000..9bffcc75e --- /dev/null +++ b/builtins/help.def~ @@ -0,0 +1,544 @@ +This file is help.def, from which is created help.c. +It implements the builtin "help" in Bash. + +Copyright (C) 1987-2013 Free Software Foundation, Inc. + +This file is part of GNU Bash, the Bourne Again SHell. + +Bash is free software: you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation, either version 3 of the License, or +(at your option) any later version. + +Bash is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with Bash. If not, see . + +$PRODUCES help.c + +$BUILTIN help +$FUNCTION help_builtin +$DEPENDS_ON HELP_BUILTIN +$SHORT_DOC help [-dms] [pattern ...] +Display information about builtin commands. + +Displays brief summaries of builtin commands. If PATTERN is +specified, gives detailed help on all commands matching PATTERN, +otherwise the list of help topics is printed. + +Options: + -d output short description for each topic + -m display usage in pseudo-manpage format + -s output only a short usage synopsis for each topic matching + PATTERN + +Arguments: + PATTERN Pattern specifiying a help topic + +Exit Status: +Returns success unless PATTERN is not found or an invalid option is given. +$END + +#include + +#if defined (HELP_BUILTIN) +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include + +#include +#include + +#include "../bashintl.h" + +#include "../shell.h" +#include "../builtins.h" +#include "../pathexp.h" +#include "common.h" +#include "bashgetopt.h" + +#include +#include + +#ifndef errno +extern int errno; +#endif + +extern const char * const bash_copyright; +extern const char * const bash_license; + +extern char *this_command_name; +extern struct builtin *current_builtin; + +static void show_builtin_command_help __P((void)); +static int open_helpfile __P((char *)); +static void show_desc __P((char *, int)); +static void show_manpage __P((char *, int)); +static void show_longdoc __P((int)); + +/* Print out a list of the known functions in the shell, and what they do. + If LIST is supplied, print out the list which matches for each pattern + specified. */ +int +help_builtin (list) + WORD_LIST *list; +{ + register int i; + char *pattern, *name; + int plen, match_found, sflag, dflag, mflag, m, pass, this_found; + + dflag = sflag = mflag = 0; + reset_internal_getopt (); + while ((i = internal_getopt (list, "dms")) != -1) + { + switch (i) + { + case 'd': + dflag = 1; + break; + case 'm': + mflag = 1; + break; + case 's': + sflag = 1; + break; + default: + builtin_usage (); + return (EX_USAGE); + } + } + list = loptend; + + if (list == 0) + { + show_shell_version (0); + show_builtin_command_help (); + return (EXECUTION_SUCCESS); + } + + /* We should consider making `help bash' do something. */ + + if (glob_pattern_p (list->word->word)) + { + printf (ngettext ("Shell commands matching keyword `", "Shell commands matching keywords `", (list->next ? 2 : 1))); + print_word_list (list, ", "); + printf ("'\n\n"); + } + + for (match_found = 0, pattern = ""; list; list = list->next) + { + pattern = list->word->word; + plen = strlen (pattern); + + for (pass = 1, this_found = 0; pass < 3; pass++) + { + for (i = 0; name = shell_builtins[i].name; i++) + { + QUIT; + + /* First pass: look for exact string or pattern matches. + Second pass: look for prefix matches like bash-4.2 */ + if (pass == 1) + m = (strcmp (pattern, name) == 0) || + (strmatch (pattern, name, FNMATCH_EXTFLAG) != FNM_NOMATCH); + else + m = strncmp (pattern, name, plen) == 0; + + if (m) + { + this_found = 1; + match_found++; + if (dflag) + { + show_desc (name, i); + continue; + } + else if (mflag) + { + show_manpage (name, i); + continue; + } + + printf ("%s: %s\n", name, _(shell_builtins[i].short_doc)); + + if (sflag == 0) + show_longdoc (i); + } + } + if (pass == 1 && this_found == 1) + break; + } + } + + if (match_found == 0) + { + builtin_error (_("no help topics match `%s'. Try `help help' or `man -k %s' or `info %s'."), pattern, pattern, pattern); + return (EXECUTION_FAILURE); + } + + fflush (stdout); + return (EXECUTION_SUCCESS); +} + +void +builtin_help () +{ + int ind; + ptrdiff_t d; + +itrace("builtin_help: this_command_name = %s", this_command_name); + + current_builtin = builtin_address_internal (this_command_name, 0); + if (current_builtin == 0) + return; + + d = current_builtin - shell_builtins; +itrace("builtin_help: current_builtin = %p diff = %d", current_builtin, (int)d); + + ind = (int)d; + + printf ("%s: %s\n", this_command_name, _(shell_builtins[ind].short_doc)); + show_longdoc (ind); +} + +static int +open_helpfile (name) + char *name; +{ + int fd; + + fd = open (name, O_RDONLY); + if (fd == -1) + { + builtin_error (_("%s: cannot open: %s"), name, strerror (errno)); + return -1; + } + return fd; +} + +/* By convention, enforced by mkbuiltins.c, if separate help files are being + used, the long_doc array contains one string -- the full pathname of the + help file for this builtin. */ +static void +show_longdoc (i) + int i; +{ + register int j; + char * const *doc; + int fd; + + doc = shell_builtins[i].long_doc; + + if (doc && doc[0] && *doc[0] == '/' && doc[1] == (char *)NULL) + { + fd = open_helpfile (doc[0]); + if (fd < 0) + return; + zcatfd (fd, 1, doc[0]); + close (fd); + } + else if (doc) + for (j = 0; doc[j]; j++) + printf ("%*s%s\n", BASE_INDENT, " ", _(doc[j])); +} + +static void +show_desc (name, i) + char *name; + int i; +{ + register int j; + char **doc, *line; + int fd, usefile; + + doc = (char **)shell_builtins[i].long_doc; + + usefile = (doc && doc[0] && *doc[0] == '/' && doc[1] == (char *)NULL); + if (usefile) + { + fd = open_helpfile (doc[0]); + if (fd < 0) + return; + zmapfd (fd, &line, doc[0]); + close (fd); + } + else + line = doc ? doc[0] : (char *)NULL; + + printf ("%s - ", name); + for (j = 0; line && line[j]; j++) + { + putchar (line[j]); + if (line[j] == '\n') + break; + } + + fflush (stdout); + + if (usefile) + free (line); +} + +/* Print builtin help in pseudo-manpage format. */ +static void +show_manpage (name, i) + char *name; + int i; +{ + register int j; + char **doc, *line; + int fd, usefile; + + doc = (char **)shell_builtins[i].long_doc; + + usefile = (doc && doc[0] && *doc[0] == '/' && doc[1] == (char *)NULL); + if (usefile) + { + fd = open_helpfile (doc[0]); + if (fd < 0) + return; + zmapfd (fd, &line, doc[0]); + close (fd); + } + else + line = doc ? _(doc[0]) : (char *)NULL; + + /* NAME */ + printf ("NAME\n"); + printf ("%*s%s - ", BASE_INDENT, " ", name); + for (j = 0; line && line[j]; j++) + { + putchar (line[j]); + if (line[j] == '\n') + break; + } + printf ("\n"); + + /* SYNOPSIS */ + printf ("SYNOPSIS\n"); + printf ("%*s%s\n\n", BASE_INDENT, " ", _(shell_builtins[i].short_doc)); + + /* DESCRIPTION */ + printf ("DESCRIPTION\n"); + if (usefile == 0) + { + for (j = 0; doc[j]; j++) + printf ("%*s%s\n", BASE_INDENT, " ", _(doc[j])); + } + else + { + for (j = 0; line && line[j]; j++) + { + putchar (line[j]); + if (line[j] == '\n') + printf ("%*s", BASE_INDENT, " "); + } + } + putchar ('\n'); + + /* SEE ALSO */ + printf ("SEE ALSO\n"); + printf ("%*sbash(1)\n\n", BASE_INDENT, " "); + + /* IMPLEMENTATION */ + printf ("IMPLEMENTATION\n"); + printf ("%*s", BASE_INDENT, " "); + show_shell_version (0); + printf ("%*s", BASE_INDENT, " "); + printf ("%s\n", _(bash_copyright)); + printf ("%*s", BASE_INDENT, " "); + printf ("%s\n", _(bash_license)); + + fflush (stdout); + if (usefile) + free (line); +} + +static void +dispcolumn (i, buf, bufsize, width, height) + int i; + char *buf; + size_t bufsize; + int width, height; +{ + int j; + int displen; + char *helpdoc; + + /* first column */ + helpdoc = _(shell_builtins[i].short_doc); + + buf[0] = (shell_builtins[i].flags & BUILTIN_ENABLED) ? ' ' : '*'; + strncpy (buf + 1, helpdoc, width - 2); + buf[width - 2] = '>'; /* indicate truncation */ + buf[width - 1] = '\0'; + printf ("%s", buf); + if (((i << 1) >= num_shell_builtins) || (i+height >= num_shell_builtins)) + { + printf ("\n"); + return; + } + + displen = strlen (buf); + /* two spaces */ + for (j = displen; j < width; j++) + putc (' ', stdout); + + /* second column */ + helpdoc = _(shell_builtins[i+height].short_doc); + + buf[0] = (shell_builtins[i+height].flags & BUILTIN_ENABLED) ? ' ' : '*'; + strncpy (buf + 1, helpdoc, width - 3); + buf[width - 3] = '>'; /* indicate truncation */ + buf[width - 2] = '\0'; + + printf ("%s\n", buf); +} + +#if defined (HANDLE_MULTIBYTE) +static void +wdispcolumn (i, buf, bufsize, width, height) + int i; + char *buf; + size_t bufsize; + int width, height; +{ + int j; + int displen; + char *helpdoc; + wchar_t *wcstr; + size_t slen, n; + int wclen; + + /* first column */ + helpdoc = _(shell_builtins[i].short_doc); + + wcstr = 0; + slen = mbstowcs ((wchar_t *)0, helpdoc, 0); + if (slen == -1) + { + dispcolumn (i, buf, bufsize, width, height); + return; + } + + /* No bigger than the passed max width */ + if (slen >= width) + slen = width - 2; + wcstr = (wchar_t *)xmalloc (sizeof (wchar_t) * (width + 2)); + n = mbstowcs (wcstr+1, helpdoc, slen + 1); + wcstr[n+1] = L'\0'; + + /* Turn tabs and newlines into spaces for column display, since wcwidth + returns -1 for them */ + for (j = 1; j < n; j++) + if (wcstr[j] == L'\n' || wcstr[j] == L'\t') + wcstr[j] = L' '; + + displen = wcsnwidth (wcstr+1, slen, width - 2) + 1; /* +1 for ' ' or '*' */ + + wcstr[0] = (shell_builtins[i].flags & BUILTIN_ENABLED) ? L' ' : L'*'; + + /* This assumes each wide char takes up one column position when displayed */ + wcstr[width - 2] = L'>'; /* indicate truncation */ + wcstr[width - 1] = L'\0'; + + printf ("%ls", wcstr); + if (((i << 1) >= num_shell_builtins) || (i+height >= num_shell_builtins)) + { + printf ("\n"); + free (wcstr); + return; + } + + /* at least one space */ + for (j = displen; j < width; j++) + putc (' ', stdout); + + /* second column */ + helpdoc = _(shell_builtins[i+height].short_doc); + slen = mbstowcs ((wchar_t *)0, helpdoc, 0); + if (slen == -1) + { + /* for now */ + printf ("%c%s\n", (shell_builtins[i+height].flags & BUILTIN_ENABLED) ? ' ' : '*', helpdoc); + free (wcstr); + return; + } + + /* Reuse wcstr since it is already width wide chars long */ + if (slen >= width) + slen = width - 2; + n = mbstowcs (wcstr+1, helpdoc, slen + 1); + wcstr[n+1] = L'\0'; /* make sure null-terminated */ + + /* Turn tabs and newlines into spaces for column display */ + for (j = 1; j < n; j++) + if (wcstr[j] == L'\n' || wcstr[j] == L'\t') + wcstr[j] = L' '; + + displen = wcsnwidth (wcstr+1, slen, width - 2); + + wcstr[0] = (shell_builtins[i+height].flags & BUILTIN_ENABLED) ? L' ' : L'*'; + + /* This assumes each wide char takes up one column position when displayed */ + wcstr[width - 3] = L'>'; /* indicate truncation */ + wcstr[width - 2] = L'\0'; + + printf ("%ls\n", wcstr); + + free (wcstr); +} +#endif /* HANDLE_MULTIBYTE */ + +static void +show_builtin_command_help () +{ + int i, j; + int height, width; + char *t, blurb[128]; + + printf ( +_("These shell commands are defined internally. Type `help' to see this list.\n\ +Type `help name' to find out more about the function `name'.\n\ +Use `info bash' to find out more about the shell in general.\n\ +Use `man -k' or `info' to find out more about commands not in this list.\n\ +\n\ +A star (*) next to a name means that the command is disabled.\n\ +\n")); + + t = get_string_value ("COLUMNS"); + width = (t && *t) ? atoi (t) : 80; + if (width <= 0) + width = 80; + + width /= 2; + if (width > sizeof (blurb)) + width = sizeof (blurb); + if (width <= 3) + width = 40; + height = (num_shell_builtins + 1) / 2; /* number of rows */ + + for (i = 0; i < height; i++) + { + QUIT; + +#if defined (HANDLE_MULTIBYTE) + if (MB_CUR_MAX > 1) + wdispcolumn (i, blurb, sizeof (blurb), width, height); + else +#endif + dispcolumn (i, blurb, sizeof (blurb), width, height); + } +} +#endif /* HELP_BUILTIN */ diff --git a/builtins/kill.def b/builtins/kill.def index 2e68f0348..fdcffc618 100644 --- a/builtins/kill.def +++ b/builtins/kill.def @@ -96,6 +96,7 @@ kill_builtin (list) builtin_usage (); return (EX_USAGE); } + CHECK_HELPOPT (list); any_succeeded = listing = saw_signal = 0; sig = SIGTERM; diff --git a/builtins/kill.def~ b/builtins/kill.def~ new file mode 100644 index 000000000..2527a5af2 --- /dev/null +++ b/builtins/kill.def~ @@ -0,0 +1,270 @@ +This file is kill.def, from which is created kill.c. +It implements the builtin "kill" in Bash. + +Copyright (C) 1987-2010 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 3 of the License, 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. If not, see . + +$PRODUCES kill.c + +$BUILTIN kill +$FUNCTION kill_builtin +$SHORT_DOC kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... or kill -l [sigspec] +Send a signal to a job. + +Send the processes identified by PID or JOBSPEC the signal named by +SIGSPEC or SIGNUM. If neither SIGSPEC nor SIGNUM is present, then +SIGTERM is assumed. + +Options: + -s sig SIG is a signal name + -n sig SIG is a signal number + -l list the signal names; if arguments follow `-l' they are + assumed to be signal numbers for which names should be listed + +Kill is a shell builtin for two reasons: it allows job IDs to be used +instead of process IDs, and allows processes to be killed if the limit +on processes that you can create is reached. + +Exit Status: +Returns success unless an invalid option is given or an error occurs. +$END + +#include + +#include +#include +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashansi.h" +#include "../bashintl.h" + +#include + +#include "../shell.h" +#include "../trap.h" +#include "../jobs.h" +#include "common.h" + +/* Not all systems declare ERRNO in errno.h... and some systems #define it! */ +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +extern int posixly_correct; + +static void kill_error __P((pid_t, int)); + +#if !defined (CONTINUE_AFTER_KILL_ERROR) +# define CONTINUE_OR_FAIL return (EXECUTION_FAILURE) +#else +# define CONTINUE_OR_FAIL goto continue_killing +#endif /* CONTINUE_AFTER_KILL_ERROR */ + +/* Here is the kill builtin. We only have it so that people can type + kill -KILL %1? No, if you fill up the process table this way you + can still kill some. */ +int +kill_builtin (list) + WORD_LIST *list; +{ + int sig, any_succeeded, listing, saw_signal, dflags; + char *sigspec, *word; + pid_t pid; + intmax_t pid_value; + + if (list == 0) + { + builtin_usage (); + return (EX_USAGE); + } + + any_succeeded = listing = saw_signal = 0; + sig = SIGTERM; + sigspec = "TERM"; + + dflags = DSIG_NOCASE | ((posixly_correct == 0) ? DSIG_SIGPREFIX : 0); + /* Process options. */ + while (list) + { + word = list->word->word; + + if (ISOPTION (word, 'l')) + { + listing++; + list = list->next; + } + else if (ISOPTION (word, 's') || ISOPTION (word, 'n')) + { + list = list->next; + if (list) + { + sigspec = list->word->word; + if (sigspec[0] == '0' && sigspec[1] == '\0') + sig = 0; + else + sig = decode_signal (sigspec, dflags); + list = list->next; + saw_signal++; + } + else + { + sh_needarg (word); + return (EXECUTION_FAILURE); + } + } + else if (ISOPTION (word, '-')) + { + list = list->next; + break; + } + else if (ISHELP (word)) + { + builtin_help (); + return (EX_USAGE); + } + else if (ISOPTION (word, '?')) + { + builtin_usage (); + return (EX_USAGE); + } + /* If this is a signal specification then process it. We only process + the first one seen; other arguments may signify process groups (e.g, + -num == process group num). */ + else if (*word == '-' && saw_signal == 0) + { + sigspec = word + 1; + sig = decode_signal (sigspec, dflags); + saw_signal++; + list = list->next; + } + else + break; + } + + if (listing) + return (display_signal_list (list, 0)); + + /* OK, we are killing processes. */ + if (sig == NO_SIG) + { + sh_invalidsig (sigspec); + return (EXECUTION_FAILURE); + } + + if (list == 0) + { + builtin_usage (); + return (EX_USAGE); + } + + while (list) + { + word = list->word->word; + + if (*word == '-') + word++; + + /* Use the entire argument in case of minus sign presence. */ + if (*word && legal_number (list->word->word, &pid_value) && (pid_value == (pid_t)pid_value)) + { + pid = (pid_t) pid_value; + + if (kill_pid (pid, sig, pid < -1) < 0) + { + if (errno == EINVAL) + sh_invalidsig (sigspec); + else + kill_error (pid, errno); + CONTINUE_OR_FAIL; + } + else + any_succeeded++; + } +#if defined (JOB_CONTROL) + else if (*list->word->word && *list->word->word != '%') + { + builtin_error (_("%s: arguments must be process or job IDs"), list->word->word); + CONTINUE_OR_FAIL; + } + else if (*word) + /* Posix.2 says you can kill without job control active (4.32.4) */ + { /* Must be a job spec. Check it out. */ + int job; + sigset_t set, oset; + JOB *j; + + BLOCK_CHILD (set, oset); + job = get_job_spec (list); + + if (INVALID_JOB (job)) + { + if (job != DUP_JOB) + sh_badjob (list->word->word); + UNBLOCK_CHILD (oset); + CONTINUE_OR_FAIL; + } + + j = get_job_by_jid (job); + /* Job spec used. Kill the process group. If the job was started + without job control, then its pgrp == shell_pgrp, so we have + to be careful. We take the pid of the first job in the pipeline + in that case. */ + pid = IS_JOBCONTROL (job) ? j->pgrp : j->pipe->pid; + + UNBLOCK_CHILD (oset); + + if (kill_pid (pid, sig, 1) < 0) + { + if (errno == EINVAL) + sh_invalidsig (sigspec); + else + kill_error (pid, errno); + CONTINUE_OR_FAIL; + } + else + any_succeeded++; + } +#endif /* !JOB_CONTROL */ + else + { + sh_badpid (list->word->word); + CONTINUE_OR_FAIL; + } + continue_killing: + list = list->next; + } + + return (any_succeeded ? EXECUTION_SUCCESS : EXECUTION_FAILURE); +} + +static void +kill_error (pid, e) + pid_t pid; + int e; +{ + char *x; + + x = strerror (e); + if (x == 0) + x = _("Unknown error"); + builtin_error ("(%ld) - %s", (long)pid, x); +} diff --git a/builtins/let.def b/builtins/let.def index 811534e48..23e684fdc 100644 --- a/builtins/let.def +++ b/builtins/let.def @@ -86,6 +86,8 @@ let_builtin (list) intmax_t ret; int expok; + CHECK_HELPOPT (list); + /* Skip over leading `--' argument. */ if (list && list->word && ISOPTION (list->word->word, '-')) list = list->next; diff --git a/builtins/let.def~ b/builtins/let.def~ new file mode 100644 index 000000000..36a1a1356 --- /dev/null +++ b/builtins/let.def~ @@ -0,0 +1,135 @@ +This file is let.def, from which is created let.c. +It implements the builtin "let" in Bash. + +Copyright (C) 1987-2009 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 3 of the License, 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. If not, see . + +$BUILTIN let +$FUNCTION let_builtin +$PRODUCES let.c +$SHORT_DOC let arg [arg ...] +Evaluate arithmetic expressions. + +Evaluate each ARG as an arithmetic expression. Evaluation is done in +fixed-width integers with no check for overflow, though division by 0 +is trapped and flagged as an error. The following list of operators is +grouped into levels of equal-precedence operators. The levels are listed +in order of decreasing precedence. + + id++, id-- variable post-increment, post-decrement + ++id, --id variable pre-increment, pre-decrement + -, + unary minus, plus + !, ~ logical and bitwise negation + ** exponentiation + *, /, % multiplication, division, remainder + +, - addition, subtraction + <<, >> left and right bitwise shifts + <=, >=, <, > comparison + ==, != equality, inequality + & bitwise AND + ^ bitwise XOR + | bitwise OR + && logical AND + || logical OR + expr ? expr : expr + conditional operator + =, *=, /=, %=, + +=, -=, <<=, >>=, + &=, ^=, |= assignment + +Shell variables are allowed as operands. The name of the variable +is replaced by its value (coerced to a fixed-width integer) within +an expression. The variable need not have its integer attribute +turned on to be used in an expression. + +Operators are evaluated in order of precedence. Sub-expressions in +parentheses are evaluated first and may override the precedence +rules above. + +Exit Status: +If the last ARG evaluates to 0, let returns 1; let returns 0 otherwise. +$END + +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashintl.h" + +#include "../shell.h" +#include "common.h" + +/* Arithmetic LET function. */ +int +let_builtin (list) + WORD_LIST *list; +{ + intmax_t ret; + int expok; + + if (list && list->word && ISHELP (list->word->word)) + { + builtin_help (); + return (EX_USAGE); + } + + /* Skip over leading `--' argument. */ + if (list && list->word && ISOPTION (list->word->word, '-')) + list = list->next; + + if (list == 0) + { + builtin_error (_("expression expected")); + return (EXECUTION_FAILURE); + } + + for (; list; list = list->next) + { + ret = evalexp (list->word->word, &expok); + if (expok == 0) + return (EXECUTION_FAILURE); + } + + return ((ret == 0) ? EXECUTION_FAILURE : EXECUTION_SUCCESS); +} + +#ifdef INCLUDE_UNUSED +int +exp_builtin (list) + WORD_LIST *list; +{ + char *exp; + intmax_t ret; + int expok; + + if (list == 0) + { + builtin_error (_("expression expected")); + return (EXECUTION_FAILURE); + } + + exp = string_list (list); + ret = evalexp (exp, &expok); + (void)free (exp); + return (((ret == 0) || (expok == 0)) ? EXECUTION_FAILURE : EXECUTION_SUCCESS); +} +#endif diff --git a/builtins/pushd.def b/builtins/pushd.def index 9c6548fad..1d435fa52 100644 --- a/builtins/pushd.def +++ b/builtins/pushd.def @@ -178,6 +178,8 @@ pushd_builtin (list) char direction; orig_list = list; + + CHECK_HELPOPT (list); if (list && list->word && ISOPTION (list->word->word, '-')) { list = list->next; @@ -321,6 +323,8 @@ popd_builtin (list) char direction; char *which_word; + CHECK_HELPOPT (list); + which_word = (char *)NULL; for (flags = 0, which = 0, direction = '+'; list; list = list->next) { @@ -402,6 +406,7 @@ dirs_builtin (list) intmax_t i; char *temp, *w; + CHECK_HELPOPT (list); for (flags = vflag = index_flag = 0, desired_index = -1, w = ""; list; list = list->next) { if (ISOPTION (list->word->word, 'l')) diff --git a/builtins/pushd.def~ b/builtins/pushd.def~ new file mode 100644 index 000000000..c1e32a36f --- /dev/null +++ b/builtins/pushd.def~ @@ -0,0 +1,793 @@ +This file is pushd.def, from which is created pushd.c. It implements the +builtins "pushd", "popd", and "dirs" in Bash. + +Copyright (C) 1987-2013 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 3 of the License, 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. If not, see . + +$PRODUCES pushd.c + +$BUILTIN pushd +$FUNCTION pushd_builtin +$DEPENDS_ON PUSHD_AND_POPD +$SHORT_DOC pushd [-n] [+N | -N | dir] +Add directories to stack. + +Adds a directory to the top of the directory stack, or rotates +the stack, making the new top of the stack the current working +directory. With no arguments, exchanges the top two directories. + +Options: + -n Suppresses the normal change of directory when adding + directories to the stack, so only the stack is manipulated. + +Arguments: + +N Rotates the stack so that the Nth directory (counting + from the left of the list shown by `dirs', starting with + zero) is at the top. + + -N Rotates the stack so that the Nth directory (counting + from the right of the list shown by `dirs', starting with + zero) is at the top. + + dir Adds DIR to the directory stack at the top, making it the + new current working directory. + +The `dirs' builtin displays the directory stack. + +Exit Status: +Returns success unless an invalid argument is supplied or the directory +change fails. +$END + +$BUILTIN popd +$FUNCTION popd_builtin +$DEPENDS_ON PUSHD_AND_POPD +$SHORT_DOC popd [-n] [+N | -N] +Remove directories from stack. + +Removes entries from the directory stack. With no arguments, removes +the top directory from the stack, and changes to the new top directory. + +Options: + -n Suppresses the normal change of directory when removing + directories from the stack, so only the stack is manipulated. + +Arguments: + +N Removes the Nth entry counting from the left of the list + shown by `dirs', starting with zero. For example: `popd +0' + removes the first directory, `popd +1' the second. + + -N Removes the Nth entry counting from the right of the list + shown by `dirs', starting with zero. For example: `popd -0' + removes the last directory, `popd -1' the next to last. + +The `dirs' builtin displays the directory stack. + +Exit Status: +Returns success unless an invalid argument is supplied or the directory +change fails. +$END + +$BUILTIN dirs +$FUNCTION dirs_builtin +$DEPENDS_ON PUSHD_AND_POPD +$SHORT_DOC dirs [-clpv] [+N] [-N] +Display directory stack. + +Display the list of currently remembered directories. Directories +find their way onto the list with the `pushd' command; you can get +back up through the list with the `popd' command. + +Options: + -c clear the directory stack by deleting all of the elements + -l do not print tilde-prefixed versions of directories relative + to your home directory + -p print the directory stack with one entry per line + -v print the directory stack with one entry per line prefixed + with its position in the stack + +Arguments: + +N Displays the Nth entry counting from the left of the list shown by + dirs when invoked without options, starting with zero. + + -N Displays the Nth entry counting from the right of the list shown by + dirs when invoked without options, starting with zero. + +Exit Status: +Returns success unless an invalid option is supplied or an error occurs. +$END + +#include + +#if defined (PUSHD_AND_POPD) +#include +#if defined (HAVE_SYS_PARAM_H) +# include +#endif + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashansi.h" +#include "../bashintl.h" + +#include + +#include + +#include "../shell.h" +#include "maxpath.h" +#include "common.h" +#include "builtext.h" + +#ifdef LOADABLE_BUILTIN +# include "builtins.h" +#endif + +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +/* The list of remembered directories. */ +static char **pushd_directory_list = (char **)NULL; + +/* Number of existing slots in this list. */ +static int directory_list_size; + +/* Offset to the end of the list. */ +static int directory_list_offset; + +static void pushd_error __P((int, char *)); +static void clear_directory_stack __P((void)); +static int cd_to_string __P((char *)); +static int change_to_temp __P((char *)); +static void add_dirstack_element __P((char *)); +static int get_dirstack_index __P((intmax_t, int, int *)); + +#define NOCD 0x01 +#define ROTATE 0x02 +#define LONGFORM 0x04 +#define CLEARSTAK 0x08 + +int +pushd_builtin (list) + WORD_LIST *list; +{ + WORD_LIST *orig_list; + char *temp, *current_directory, *top; + int j, flags, skipopt; + intmax_t num; + char direction; + + orig_list = list; + + CHECK_HELPOPT (list); + if (list && list->word && ISOPTION (list->word->word, '-')) + { + list = list->next; + skipopt = 1; + } + else + skipopt = 0; + + /* If there is no argument list then switch current and + top of list. */ + if (list == 0) + { + if (directory_list_offset == 0) + { + builtin_error (_("no other directory")); + return (EXECUTION_FAILURE); + } + + current_directory = get_working_directory ("pushd"); + if (current_directory == 0) + return (EXECUTION_FAILURE); + + j = directory_list_offset - 1; + temp = pushd_directory_list[j]; + pushd_directory_list[j] = current_directory; + j = change_to_temp (temp); + free (temp); + return j; + } + + for (flags = 0; skipopt == 0 && list; list = list->next) + { + if (ISOPTION (list->word->word, 'n')) + { + flags |= NOCD; + } + else if (ISOPTION (list->word->word, '-')) + { + list = list->next; + break; + } + else if (list->word->word[0] == '-' && list->word->word[1] == '\0') + /* Let `pushd -' work like it used to. */ + break; + else if (((direction = list->word->word[0]) == '+') || direction == '-') + { + if (legal_number (list->word->word + 1, &num) == 0) + { + sh_invalidnum (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + + if (direction == '-') + num = directory_list_offset - num; + + if (num > directory_list_offset || num < 0) + { + pushd_error (directory_list_offset, list->word->word); + return (EXECUTION_FAILURE); + } + flags |= ROTATE; + } + else if (*list->word->word == '-') + { + sh_invalidopt (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + else + break; + } + + if (flags & ROTATE) + { + /* Rotate the stack num times. Remember, the current + directory acts like it is part of the stack. */ + temp = get_working_directory ("pushd"); + + if (num == 0) + { + j = ((flags & NOCD) == 0) ? change_to_temp (temp) : EXECUTION_SUCCESS; + free (temp); + return j; + } + + do + { + top = pushd_directory_list[directory_list_offset - 1]; + + for (j = directory_list_offset - 2; j > -1; j--) + pushd_directory_list[j + 1] = pushd_directory_list[j]; + + pushd_directory_list[j + 1] = temp; + + temp = top; + num--; + } + while (num); + + j = ((flags & NOCD) == 0) ? change_to_temp (temp) : EXECUTION_SUCCESS; + free (temp); + return j; + } + + if (list == 0) + return (EXECUTION_SUCCESS); + + /* Change to the directory in list->word->word. Save the current + directory on the top of the stack. */ + current_directory = get_working_directory ("pushd"); + if (current_directory == 0) + return (EXECUTION_FAILURE); + + j = ((flags & NOCD) == 0) ? cd_builtin (skipopt ? orig_list : list) : EXECUTION_SUCCESS; + if (j == EXECUTION_SUCCESS) + { + add_dirstack_element ((flags & NOCD) ? savestring (list->word->word) : current_directory); + dirs_builtin ((WORD_LIST *)NULL); + if (flags & NOCD) + free (current_directory); + return (EXECUTION_SUCCESS); + } + else + { + free (current_directory); + return (EXECUTION_FAILURE); + } +} + +/* Pop the directory stack, and then change to the new top of the stack. + If LIST is non-null it should consist of a word +N or -N, which says + what element to delete from the stack. The default is the top one. */ +int +popd_builtin (list) + WORD_LIST *list; +{ + register int i; + intmax_t which; + int flags; + char direction; + char *which_word; + + CHECK_HELPOPT (list); + + which_word = (char *)NULL; + for (flags = 0, which = 0, direction = '+'; list; list = list->next) + { + if (ISOPTION (list->word->word, 'n')) + { + flags |= NOCD; + } + else if (ISOPTION (list->word->word, '-')) + { + list = list->next; + break; + } + else if (((direction = list->word->word[0]) == '+') || direction == '-') + { + if (legal_number (list->word->word + 1, &which) == 0) + { + sh_invalidnum (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + which_word = list->word->word; + } + else if (*list->word->word == '-') + { + sh_invalidopt (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + else if (*list->word->word) + { + builtin_error (_("%s: invalid argument"), list->word->word); + builtin_usage (); + return (EX_USAGE); + } + else + break; + } + + if (which > directory_list_offset || (directory_list_offset == 0 && which == 0)) + { + pushd_error (directory_list_offset, which_word ? which_word : ""); + return (EXECUTION_FAILURE); + } + + /* Handle case of no specification, or top of stack specification. */ + if ((direction == '+' && which == 0) || + (direction == '-' && which == directory_list_offset)) + { + i = ((flags & NOCD) == 0) ? cd_to_string (pushd_directory_list[directory_list_offset - 1]) + : EXECUTION_SUCCESS; + if (i != EXECUTION_SUCCESS) + return (i); + free (pushd_directory_list[--directory_list_offset]); + } + else + { + /* Since an offset other than the top directory was specified, + remove that directory from the list and shift the remainder + of the list into place. */ + i = (direction == '+') ? directory_list_offset - which : which; + free (pushd_directory_list[i]); + directory_list_offset--; + + /* Shift the remainder of the list into place. */ + for (; i < directory_list_offset; i++) + pushd_directory_list[i] = pushd_directory_list[i + 1]; + } + + dirs_builtin ((WORD_LIST *)NULL); + return (EXECUTION_SUCCESS); +} + +/* Print the current list of directories on the directory stack. */ +int +dirs_builtin (list) + WORD_LIST *list; +{ + int flags, desired_index, index_flag, vflag; + intmax_t i; + char *temp, *w; + + if (list && list->word && ISHELP (list->word->word)) + { + builtin_help (); + return (EX_USAGE); + } + for (flags = vflag = index_flag = 0, desired_index = -1, w = ""; list; list = list->next) + { + if (ISOPTION (list->word->word, 'l')) + { + flags |= LONGFORM; + } + else if (ISOPTION (list->word->word, 'c')) + { + flags |= CLEARSTAK; + } + else if (ISOPTION (list->word->word, 'v')) + { + vflag |= 2; + } + else if (ISOPTION (list->word->word, 'p')) + { + vflag |= 1; + } + else if (ISOPTION (list->word->word, '-')) + { + list = list->next; + break; + } + else if (*list->word->word == '+' || *list->word->word == '-') + { + int sign; + if (legal_number (w = list->word->word + 1, &i) == 0) + { + sh_invalidnum (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + sign = (*list->word->word == '+') ? 1 : -1; + desired_index = get_dirstack_index (i, sign, &index_flag); + } + else + { + sh_invalidopt (list->word->word); + builtin_usage (); + return (EX_USAGE); + } + } + + if (flags & CLEARSTAK) + { + clear_directory_stack (); + return (EXECUTION_SUCCESS); + } + + if (index_flag && (desired_index < 0 || desired_index > directory_list_offset)) + { + pushd_error (directory_list_offset, w); + return (EXECUTION_FAILURE); + } + +#define DIRSTACK_FORMAT(temp) \ + (flags & LONGFORM) ? temp : polite_directory_format (temp) + + /* The first directory printed is always the current working directory. */ + if (index_flag == 0 || (index_flag == 1 && desired_index == 0)) + { + temp = get_working_directory ("dirs"); + if (temp == 0) + temp = savestring (_("")); + if (vflag & 2) + printf ("%2d %s", 0, DIRSTACK_FORMAT (temp)); + else + printf ("%s", DIRSTACK_FORMAT (temp)); + free (temp); + if (index_flag) + { + putchar ('\n'); + return (sh_chkwrite (EXECUTION_SUCCESS)); + } + } + +#define DIRSTACK_ENTRY(i) \ + (flags & LONGFORM) ? pushd_directory_list[i] \ + : polite_directory_format (pushd_directory_list[i]) + + /* Now print the requested directory stack entries. */ + if (index_flag) + { + if (vflag & 2) + printf ("%2d %s", directory_list_offset - desired_index, + DIRSTACK_ENTRY (desired_index)); + else + printf ("%s", DIRSTACK_ENTRY (desired_index)); + } + else + for (i = directory_list_offset - 1; i >= 0; i--) + if (vflag >= 2) + printf ("\n%2d %s", directory_list_offset - (int)i, DIRSTACK_ENTRY (i)); + else + printf ("%s%s", (vflag & 1) ? "\n" : " ", DIRSTACK_ENTRY (i)); + + putchar ('\n'); + + return (sh_chkwrite (EXECUTION_SUCCESS)); +} + +static void +pushd_error (offset, arg) + int offset; + char *arg; +{ + if (offset == 0) + builtin_error (_("directory stack empty")); + else + sh_erange (arg, _("directory stack index")); +} + +static void +clear_directory_stack () +{ + register int i; + + for (i = 0; i < directory_list_offset; i++) + free (pushd_directory_list[i]); + directory_list_offset = 0; +} + +/* Switch to the directory in NAME. This uses the cd_builtin to do the work, + so if the result is EXECUTION_FAILURE then an error message has already + been printed. */ +static int +cd_to_string (name) + char *name; +{ + WORD_LIST *tlist; + WORD_LIST *dir; + int result; + + dir = make_word_list (make_word (name), NULL); + tlist = make_word_list (make_word ("--"), dir); + result = cd_builtin (tlist); + dispose_words (tlist); + return (result); +} + +static int +change_to_temp (temp) + char *temp; +{ + int tt; + + tt = temp ? cd_to_string (temp) : EXECUTION_FAILURE; + + if (tt == EXECUTION_SUCCESS) + dirs_builtin ((WORD_LIST *)NULL); + + return (tt); +} + +static void +add_dirstack_element (dir) + char *dir; +{ + if (directory_list_offset == directory_list_size) + pushd_directory_list = strvec_resize (pushd_directory_list, directory_list_size += 10); + pushd_directory_list[directory_list_offset++] = dir; +} + +static int +get_dirstack_index (ind, sign, indexp) + intmax_t ind; + int sign, *indexp; +{ + if (indexp) + *indexp = sign > 0 ? 1 : 2; + + /* dirs +0 prints the current working directory. */ + /* dirs -0 prints last element in directory stack */ + if (ind == 0 && sign > 0) + return 0; + else if (ind == directory_list_offset) + { + if (indexp) + *indexp = sign > 0 ? 2 : 1; + return 0; + } + else if (ind >= 0 && ind <= directory_list_offset) + return (sign > 0 ? directory_list_offset - ind : ind); + else + return -1; +} + +/* Used by the tilde expansion code. */ +char * +get_dirstack_from_string (string) + char *string; +{ + int ind, sign, index_flag; + intmax_t i; + + sign = 1; + if (*string == '-' || *string == '+') + { + sign = (*string == '-') ? -1 : 1; + string++; + } + if (legal_number (string, &i) == 0) + return ((char *)NULL); + + index_flag = 0; + ind = get_dirstack_index (i, sign, &index_flag); + if (index_flag && (ind < 0 || ind > directory_list_offset)) + return ((char *)NULL); + if (index_flag == 0 || (index_flag == 1 && ind == 0)) + return (get_string_value ("PWD")); + else + return (pushd_directory_list[ind]); +} + +#ifdef INCLUDE_UNUSED +char * +get_dirstack_element (ind, sign) + intmax_t ind; + int sign; +{ + int i; + + i = get_dirstack_index (ind, sign, (int *)NULL); + return (i < 0 || i > directory_list_offset) ? (char *)NULL + : pushd_directory_list[i]; +} +#endif + +void +set_dirstack_element (ind, sign, value) + intmax_t ind; + int sign; + char *value; +{ + int i; + + i = get_dirstack_index (ind, sign, (int *)NULL); + if (ind == 0 || i < 0 || i > directory_list_offset) + return; + free (pushd_directory_list[i]); + pushd_directory_list[i] = savestring (value); +} + +WORD_LIST * +get_directory_stack (flags) + int flags; +{ + register int i; + WORD_LIST *ret; + char *d, *t; + + for (ret = (WORD_LIST *)NULL, i = 0; i < directory_list_offset; i++) + { + d = (flags&1) ? polite_directory_format (pushd_directory_list[i]) + : pushd_directory_list[i]; + ret = make_word_list (make_word (d), ret); + } + /* Now the current directory. */ + d = get_working_directory ("dirstack"); + i = 0; /* sentinel to decide whether or not to free d */ + if (d == 0) + d = "."; + else + { + t = polite_directory_format (d); + /* polite_directory_format sometimes returns its argument unchanged. + If it does not, we can free d right away. If it does, we need to + mark d to be deleted later. */ + if (t != d) + { + free (d); + d = t; + } + else /* t == d, so d is what we want */ + i = 1; + } + ret = make_word_list (make_word (d), ret); + if (i) + free (d); + return ret; /* was (REVERSE_LIST (ret, (WORD_LIST *)); */ +} + +#ifdef LOADABLE_BUILTIN +char * const dirs_doc[] = { +N_("Display the list of currently remembered directories. Directories\n\ + find their way onto the list with the `pushd' command; you can get\n\ + back up through the list with the `popd' command.\n\ + \n\ + Options:\n\ + -c clear the directory stack by deleting all of the elements\n\ + -l do not print tilde-prefixed versions of directories relative\n\ + to your home directory\n\ + -p print the directory stack with one entry per line\n\ + -v print the directory stack with one entry per line prefixed\n\ + with its position in the stack\n\ + \n\ + Arguments:\n\ + +N Displays the Nth entry counting from the left of the list shown by\n\ + dirs when invoked without options, starting with zero.\n\ + \n\ + -N Displays the Nth entry counting from the right of the list shown by\n\ + dirs when invoked without options, starting with zero."), + (char *)NULL +}; + +char * const pushd_doc[] = { +N_("Adds a directory to the top of the directory stack, or rotates\n\ + the stack, making the new top of the stack the current working\n\ + directory. With no arguments, exchanges the top two directories.\n\ + \n\ + Options:\n\ + -n Suppresses the normal change of directory when adding\n\ + directories to the stack, so only the stack is manipulated.\n\ + \n\ + Arguments:\n\ + +N Rotates the stack so that the Nth directory (counting\n\ + from the left of the list shown by `dirs', starting with\n\ + zero) is at the top.\n\ + \n\ + -N Rotates the stack so that the Nth directory (counting\n\ + from the right of the list shown by `dirs', starting with\n\ + zero) is at the top.\n\ + \n\ + dir Adds DIR to the directory stack at the top, making it the\n\ + new current working directory.\n\ + \n\ + The `dirs' builtin displays the directory stack."), + (char *)NULL +}; + +char * const popd_doc[] = { +N_("Removes entries from the directory stack. With no arguments, removes\n\ + the top directory from the stack, and changes to the new top directory.\n\ + \n\ + Options:\n\ + -n Suppresses the normal change of directory when removing\n\ + directories from the stack, so only the stack is manipulated.\n\ + \n\ + Arguments:\n\ + +N Removes the Nth entry counting from the left of the list\n\ + shown by `dirs', starting with zero. For example: `popd +0'\n\ + removes the first directory, `popd +1' the second.\n\ + \n\ + -N Removes the Nth entry counting from the right of the list\n\ + shown by `dirs', starting with zero. For example: `popd -0'\n\ + removes the last directory, `popd -1' the next to last.\n\ + \n\ + The `dirs' builtin displays the directory stack."), + (char *)NULL +}; + +struct builtin pushd_struct = { + "pushd", + pushd_builtin, + BUILTIN_ENABLED, + pushd_doc, + "pushd [+N | -N] [-n] [dir]", + 0 +}; + +struct builtin popd_struct = { + "popd", + popd_builtin, + BUILTIN_ENABLED, + popd_doc, + "popd [+N | -N] [-n]", + 0 +}; + +struct builtin dirs_struct = { + "dirs", + dirs_builtin, + BUILTIN_ENABLED, + dirs_doc, + "dirs [-clpv] [+N] [-N]", + 0 +}; +#endif /* LOADABLE_BUILTIN */ + +#endif /* PUSHD_AND_POPD */ diff --git a/builtins/return.def b/builtins/return.def index e6674dfa3..c1053f0f8 100644 --- a/builtins/return.def +++ b/builtins/return.def @@ -60,11 +60,7 @@ int return_builtin (list) WORD_LIST *list; { -#if 0 - if (no_options (list)) - return (EX_USAGE); - list = loptend; /* skip over possible `--' */ -#endif + CHECK_HELPOPT (list); return_catch_value = get_exitstat (list); diff --git a/builtins/return.def~ b/builtins/return.def~ new file mode 100644 index 000000000..9a84817f2 --- /dev/null +++ b/builtins/return.def~ @@ -0,0 +1,72 @@ +This file is return.def, from which is created return.c. +It implements the builtin "return" in Bash. + +Copyright (C) 1987-2009 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 3 of the License, 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. If not, see . + +$PRODUCES return.c + +$BUILTIN return + +$FUNCTION return_builtin +$SHORT_DOC return [n] +Return from a shell function. + +Causes a function or sourced script to exit with the return value +specified by N. If N is omitted, the return status is that of the +last command executed within the function or script. + +Exit Status: +Returns N, or failure if the shell is not executing a function or script. +$END + +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashintl.h" + +#include "../shell.h" +#include "common.h" +#include "bashgetopt.h" + +extern int last_command_exit_value; +extern int subshell_environment; +extern int return_catch_flag, return_catch_value; + +/* If we are executing a user-defined function then exit with the value + specified as an argument. if no argument is given, then the last + exit status is used. */ +int +return_builtin (list) + WORD_LIST *list; +{ + return_catch_value = get_exitstat (list); + + if (return_catch_flag) + longjmp (return_catch, 1); + else + { + builtin_error (_("can only `return' from a function or sourced script")); + return (EXECUTION_FAILURE); + } +} diff --git a/builtins/shift.def b/builtins/shift.def index 32130862a..98fc94d73 100644 --- a/builtins/shift.def +++ b/builtins/shift.def @@ -61,6 +61,8 @@ shift_builtin (list) register int count; WORD_LIST *temp; + CHECK_HELPOPT (list); + if (get_numeric_arg (list, 0, ×) == 0) return (EXECUTION_FAILURE); diff --git a/builtins/shift.def~ b/builtins/shift.def~ new file mode 100644 index 000000000..32130862a --- /dev/null +++ b/builtins/shift.def~ @@ -0,0 +1,101 @@ +This file is shift.def, from which is created shift.c. +It implements the builtin "shift" in Bash. + +Copyright (C) 1987-2009 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 3 of the License, 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. If not, see . + +$PRODUCES shift.c + +#include + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include +# endif +# include +#endif + +#include "../bashansi.h" +#include "../bashintl.h" + +#include "../shell.h" +#include "common.h" + +$BUILTIN shift +$FUNCTION shift_builtin +$SHORT_DOC shift [n] +Shift positional parameters. + +Rename the positional parameters $N+1,$N+2 ... to $1,$2 ... If N is +not given, it is assumed to be 1. + +Exit Status: +Returns success unless N is negative or greater than $#. +$END + +int print_shift_error; + +/* Shift the arguments ``left''. Shift DOLLAR_VARS down then take one + off of REST_OF_ARGS and place it into DOLLAR_VARS[9]. If LIST has + anything in it, it is a number which says where to start the + shifting. Return > 0 if `times' > $#, otherwise 0. */ +int +shift_builtin (list) + WORD_LIST *list; +{ + intmax_t times; + register int count; + WORD_LIST *temp; + + if (get_numeric_arg (list, 0, ×) == 0) + return (EXECUTION_FAILURE); + + if (times == 0) + return (EXECUTION_SUCCESS); + else if (times < 0) + { + sh_erange (list ? list->word->word : NULL, _("shift count")); + return (EXECUTION_FAILURE); + } + else if (times > number_of_args ()) + { + if (print_shift_error) + sh_erange (list ? list->word->word : NULL, _("shift count")); + return (EXECUTION_FAILURE); + } + + while (times-- > 0) + { + if (dollar_vars[1]) + free (dollar_vars[1]); + + for (count = 1; count < 9; count++) + dollar_vars[count] = dollar_vars[count + 1]; + + if (rest_of_args) + { + temp = rest_of_args; + dollar_vars[9] = savestring (temp->word->word); + rest_of_args = rest_of_args->next; + temp->next = (WORD_LIST *)NULL; + dispose_words (temp); + } + else + dollar_vars[9] = (char *)NULL; + } + return (EXECUTION_SUCCESS); +} diff --git a/config-top.h b/config-top.h index 5e3cb9a01..8bae50650 100644 --- a/config-top.h +++ b/config-top.h @@ -143,3 +143,11 @@ /* Define to 1 if you want the shell to re-check $PATH if a hashed filename no longer exists. This behavior is the default in Posix mode. */ #define CHECKHASH_DEFAULT 0 + +/* Define to the maximum level of recursion you want for the eval builtin. + 0 means the limit is not active. */ +#define EVALNEST_MAX 0 + +/* Define to the maximum level of recursion you want for the source/. builtin. + 0 means the limit is not active. */ +#define SOURCENEST_MAX 0 diff --git a/doc/bashref.texi b/doc/bashref.texi index 1c0b3123d..317244b3a 100644 --- a/doc/bashref.texi +++ b/doc/bashref.texi @@ -7245,6 +7245,11 @@ builtins. @sc{posix} special builtins are found before shell functions during command lookup. +@item +Literal tildes that appear as the first character in elements of +the @env{PATH} variable are not expanded as described above +under @ref{Tilde Expansion}. + @item The @code{time} reserved word may be used by itself as a command. When used in this way, it displays timing statistics for the shell and its diff --git a/doc/bashref.texi~ b/doc/bashref.texi~ new file mode 100644 index 000000000..1c0b3123d --- /dev/null +++ b/doc/bashref.texi~ @@ -0,0 +1,8762 @@ +\input texinfo.tex @c -*- texinfo -*- +@c %**start of header +@setfilename bashref.info +@settitle Bash Reference Manual + +@include version.texi +@c %**end of header + +@copying +This text is a brief description of the features that are present in +the Bash shell (version @value{VERSION}, @value{UPDATED}). + +This is Edition @value{EDITION}, last updated @value{UPDATED}, +of @cite{The GNU Bash Reference Manual}, +for @code{Bash}, Version @value{VERSION}. + +Copyright @copyright{} 1988--2014 Free Software Foundation, Inc. + +@quotation +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with no +Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. +A copy of the license is included in the section entitled +``GNU Free Documentation License''. +@end quotation +@end copying + +@defcodeindex bt +@defcodeindex rw +@set BashFeatures + +@dircategory Basics +@direntry +* Bash: (bash). The GNU Bourne-Again SHell. +@end direntry + +@finalout + +@titlepage +@title Bash Reference Manual +@subtitle Reference Documentation for Bash +@subtitle Edition @value{EDITION}, for @code{Bash} Version @value{VERSION}. +@subtitle @value{UPDATED-MONTH} +@author Chet Ramey, Case Western Reserve University +@author Brian Fox, Free Software Foundation + +@page +@vskip 0pt plus 1filll +@insertcopying + +@end titlepage + +@contents + +@ifnottex +@node Top, Introduction, (dir), (dir) +@top Bash Features + +This text is a brief description of the features that are present in +the Bash shell (version @value{VERSION}, @value{UPDATED}). +The Bash home page is @url{http://www.gnu.org/software/bash/}. + +This is Edition @value{EDITION}, last updated @value{UPDATED}, +of @cite{The GNU Bash Reference Manual}, +for @code{Bash}, Version @value{VERSION}. + +Bash contains features that appear in other popular shells, and some +features that only appear in Bash. Some of the shells that Bash has +borrowed concepts from are the Bourne Shell (@file{sh}), the Korn Shell +(@file{ksh}), and the C-shell (@file{csh} and its successor, +@file{tcsh}). The following menu breaks the features up into +categories, noting which features were inspired by other shells and +which are specific to Bash. + +This manual is meant as a brief introduction to features found in +Bash. The Bash manual page should be used as the definitive +reference on shell behavior. + +@menu +* Introduction:: An introduction to the shell. +* Definitions:: Some definitions used in the rest of this + manual. +* Basic Shell Features:: The shell "building blocks". +* Shell Builtin Commands:: Commands that are a part of the shell. +* Shell Variables:: Variables used or set by Bash. +* Bash Features:: Features found only in Bash. +* Job Control:: What job control is and how Bash allows you + to use it. +* Command Line Editing:: Chapter describing the command line + editing features. +* Using History Interactively:: Command History Expansion +* Installing Bash:: How to build and install Bash on your system. +* Reporting Bugs:: How to report bugs in Bash. +* Major Differences From The Bourne Shell:: A terse list of the differences + between Bash and historical + versions of /bin/sh. +* GNU Free Documentation License:: Copying and sharing this documentation. +* Indexes:: Various indexes for this manual. +@end menu +@end ifnottex + +@node Introduction +@chapter Introduction +@menu +* What is Bash?:: A short description of Bash. +* What is a shell?:: A brief introduction to shells. +@end menu + +@node What is Bash? +@section What is Bash? + +Bash is the shell, or command language interpreter, +for the @sc{gnu} operating system. +The name is an acronym for the @samp{Bourne-Again SHell}, +a pun on Stephen Bourne, the author of the direct ancestor of +the current Unix shell @code{sh}, +which appeared in the Seventh Edition Bell Labs Research version +of Unix. + +Bash is largely compatible with @code{sh} and incorporates useful +features from the Korn shell @code{ksh} and the C shell @code{csh}. +It is intended to be a conformant implementation of the @sc{ieee} +@sc{posix} Shell and Tools portion of the @sc{ieee} @sc{posix} +specification (@sc{ieee} Standard 1003.1). +It offers functional improvements over @code{sh} for both interactive and +programming use. + +While the @sc{gnu} operating system provides other shells, including +a version of @code{csh}, Bash is the default shell. +Like other @sc{gnu} software, Bash is quite portable. It currently runs +on nearly every version of Unix and a few other operating systems @minus{} +independently-supported ports exist for @sc{ms-dos}, @sc{os/2}, +and Windows platforms. + +@node What is a shell? +@section What is a shell? + +At its base, a shell is simply a macro processor that executes +commands. The term macro processor means functionality where text +and symbols are expanded to create larger expressions. + +A Unix shell is both a command interpreter and a programming +language. As a command interpreter, the shell provides the user +interface to the rich set of @sc{gnu} utilities. The programming +language features allow these utilities to be combined. +Files containing commands can be created, and become +commands themselves. These new commands have the same status as +system commands in directories such as @file{/bin}, allowing users +or groups to establish custom environments to automate their common +tasks. + +Shells may be used interactively or non-interactively. In +interactive mode, they accept input typed from the keyboard. +When executing non-interactively, shells execute commands read +from a file. + +A shell allows execution of @sc{gnu} commands, both synchronously and +asynchronously. +The shell waits for synchronous commands to complete before accepting +more input; asynchronous commands continue to execute in parallel +with the shell while it reads and executes additional commands. +The @dfn{redirection} constructs permit +fine-grained control of the input and output of those commands. +Moreover, the shell allows control over the contents of commands' +environments. + +Shells also provide a small set of built-in +commands (@dfn{builtins}) implementing functionality impossible +or inconvenient to obtain via separate utilities. +For example, @code{cd}, @code{break}, @code{continue}, and +@code{exec} cannot be implemented outside of the shell because +they directly manipulate the shell itself. +The @code{history}, @code{getopts}, @code{kill}, or @code{pwd} +builtins, among others, could be implemented in separate utilities, +but they are more convenient to use as builtin commands. +All of the shell builtins are described in +subsequent sections. + +While executing commands is essential, most of the power (and +complexity) of shells is due to their embedded programming +languages. Like any high-level language, the shell provides +variables, flow control constructs, quoting, and functions. + +Shells offer features geared specifically for +interactive use rather than to augment the programming language. +These interactive features include job control, command line +editing, command history and aliases. Each of these features is +described in this manual. + +@node Definitions +@chapter Definitions +These definitions are used throughout the remainder of this manual. + +@table @code + +@item POSIX +@cindex POSIX +A family of open system standards based on Unix. Bash +is primarily concerned with the Shell and Utilities portion of the +@sc{posix} 1003.1 standard. + +@item blank +A space or tab character. + +@item builtin +@cindex builtin +A command that is implemented internally by the shell itself, rather +than by an executable program somewhere in the file system. + +@item control operator +@cindex control operator +A @code{token} that performs a control function. It is a @code{newline} +or one of the following: +@samp{||}, @samp{&&}, @samp{&}, @samp{;}, @samp{;;}, +@samp{|}, @samp{|&}, @samp{(}, or @samp{)}. + +@item exit status +@cindex exit status +The value returned by a command to its caller. The value is restricted +to eight bits, so the maximum value is 255. + +@item field +@cindex field +A unit of text that is the result of one of the shell expansions. After +expansion, when executing a command, the resulting fields are used as +the command name and arguments. + +@item filename +@cindex filename +A string of characters used to identify a file. + +@item job +@cindex job +A set of processes comprising a pipeline, and any processes descended +from it, that are all in the same process group. + +@item job control +@cindex job control +A mechanism by which users can selectively stop (suspend) and restart +(resume) execution of processes. + +@item metacharacter +@cindex metacharacter +A character that, when unquoted, separates words. A metacharacter is +a @code{blank} or one of the following characters: +@samp{|}, @samp{&}, @samp{;}, @samp{(}, @samp{)}, @samp{<}, or +@samp{>}. + +@item name +@cindex name +@cindex identifier +A @code{word} consisting solely of letters, numbers, and underscores, +and beginning with a letter or underscore. @code{Name}s are used as +shell variable and function names. +Also referred to as an @code{identifier}. + +@item operator +@cindex operator, shell +A @code{control operator} or a @code{redirection operator}. +@xref{Redirections}, for a list of redirection operators. +Operators contain at least one unquoted @code{metacharacter}. + +@item process group +@cindex process group +A collection of related processes each having the same process +group @sc{id}. + +@item process group ID +@cindex process group ID +A unique identifier that represents a @code{process group} +during its lifetime. + +@item reserved word +@cindex reserved word +A @code{word} that has a special meaning to the shell. Most reserved +words introduce shell flow control constructs, such as @code{for} and +@code{while}. + +@item return status +@cindex return status +A synonym for @code{exit status}. + +@item signal +@cindex signal +A mechanism by which a process may be notified by the kernel +of an event occurring in the system. + +@item special builtin +@cindex special builtin +A shell builtin command that has been classified as special by the +@sc{posix} standard. + +@item token +@cindex token +A sequence of characters considered a single unit by the shell. +It is either a @code{word} or an @code{operator}. + +@item word +@cindex word +A sequence of characters treated as a unit by the shell. +Words may not include unquoted @code{metacharacters}. +@end table + +@node Basic Shell Features +@chapter Basic Shell Features +@cindex Bourne shell + +Bash is an acronym for @samp{Bourne-Again SHell}. +The Bourne shell is +the traditional Unix shell originally written by Stephen Bourne. +All of the Bourne shell builtin commands are available in Bash, +The rules for evaluation and quoting are taken from the @sc{posix} +specification for the `standard' Unix shell. + +This chapter briefly summarizes the shell's `building blocks': +commands, control structures, shell functions, shell @i{parameters}, +shell expansions, +@i{redirections}, which are a way to direct input and output from +and to named files, and how the shell executes commands. + +@menu +* Shell Syntax:: What your input means to the shell. +* Shell Commands:: The types of commands you can use. +* Shell Functions:: Grouping commands by name. +* Shell Parameters:: How the shell stores values. +* Shell Expansions:: How Bash expands parameters and the various + expansions available. +* Redirections:: A way to control where input and output go. +* Executing Commands:: What happens when you run a command. +* Shell Scripts:: Executing files of shell commands. +@end menu + +@node Shell Syntax +@section Shell Syntax +@menu +* Shell Operation:: The basic operation of the shell. +* Quoting:: How to remove the special meaning from characters. +* Comments:: How to specify comments. +@end menu + +When the shell reads input, it proceeds through a +sequence of operations. If the input indicates the beginning of a +comment, the shell ignores the comment symbol (@samp{#}), and the rest +of that line. + +Otherwise, roughly speaking, the shell reads its input and +divides the input into words and operators, employing the quoting rules +to select which meanings to assign various words and characters. + +The shell then parses these tokens into commands and other constructs, +removes the special meaning of certain words or characters, expands +others, redirects input and output as needed, executes the specified +command, waits for the command's exit status, and makes that exit status +available for further inspection or processing. + +@node Shell Operation +@subsection Shell Operation + +The following is a brief description of the shell's operation when it +reads and executes a command. Basically, the shell does the +following: + +@enumerate +@item +Reads its input from a file (@pxref{Shell Scripts}), from a string +supplied as an argument to the @option{-c} invocation option +(@pxref{Invoking Bash}), or from the user's terminal. + +@item +Breaks the input into words and operators, obeying the quoting rules +described in @ref{Quoting}. These tokens are separated by +@code{metacharacters}. Alias expansion is performed by this step +(@pxref{Aliases}). + +@item +Parses the tokens into simple and compound commands +(@pxref{Shell Commands}). + +@item +Performs the various shell expansions (@pxref{Shell Expansions}), breaking +the expanded tokens into lists of filenames (@pxref{Filename Expansion}) +and commands and arguments. + +@item +Performs any necessary redirections (@pxref{Redirections}) and removes +the redirection operators and their operands from the argument list. + +@item +Executes the command (@pxref{Executing Commands}). + +@item +Optionally waits for the command to complete and collects its exit +status (@pxref{Exit Status}). + +@end enumerate + +@node Quoting +@subsection Quoting +@cindex quoting +@menu +* Escape Character:: How to remove the special meaning from a single + character. +* Single Quotes:: How to inhibit all interpretation of a sequence + of characters. +* Double Quotes:: How to suppress most of the interpretation of a + sequence of characters. +* ANSI-C Quoting:: How to expand ANSI-C sequences in quoted strings. +* Locale Translation:: How to translate strings into different languages. +@end menu + +Quoting is used to remove the special meaning of certain +characters or words to the shell. Quoting can be used to +disable special treatment for special characters, to prevent +reserved words from being recognized as such, and to prevent +parameter expansion. + +Each of the shell metacharacters (@pxref{Definitions}) +has special meaning to the shell and must be quoted if it is to +represent itself. +When the command history expansion facilities are being used +(@pxref{History Interaction}), the +@var{history expansion} character, usually @samp{!}, must be quoted +to prevent history expansion. @xref{Bash History Facilities}, for +more details concerning history expansion. + +There are three quoting mechanisms: the +@var{escape character}, single quotes, and double quotes. + +@node Escape Character +@subsubsection Escape Character +A non-quoted backslash @samp{\} is the Bash escape character. +It preserves the literal value of the next character that follows, +with the exception of @code{newline}. If a @code{\newline} pair +appears, and the backslash itself is not quoted, the @code{\newline} +is treated as a line continuation (that is, it is removed from +the input stream and effectively ignored). + +@node Single Quotes +@subsubsection Single Quotes + +Enclosing characters in single quotes (@samp{'}) preserves the literal value +of each character within the quotes. A single quote may not occur +between single quotes, even when preceded by a backslash. + +@node Double Quotes +@subsubsection Double Quotes + +Enclosing characters in double quotes (@samp{"}) preserves the literal value +of all characters within the quotes, with the exception of +@samp{$}, @samp{`}, @samp{\}, +and, when history expansion is enabled, @samp{!}. +The characters @samp{$} and @samp{`} +retain their special meaning within double quotes (@pxref{Shell Expansions}). +The backslash retains its special meaning only when followed by one of +the following characters: +@samp{$}, @samp{`}, @samp{"}, @samp{\}, or @code{newline}. +Within double quotes, backslashes that are followed by one of these +characters are removed. Backslashes preceding characters without a +special meaning are left unmodified. +A double quote may be quoted within double quotes by preceding it with +a backslash. +If enabled, history expansion will be performed unless an @samp{!} +appearing in double quotes is escaped using a backslash. +The backslash preceding the @samp{!} is not removed. + +The special parameters @samp{*} and @samp{@@} have special meaning +when in double quotes (@pxref{Shell Parameter Expansion}). + +@node ANSI-C Quoting +@subsubsection ANSI-C Quoting +@cindex quoting, ANSI + +Words of the form @code{$'@var{string}'} are treated specially. The +word expands to @var{string}, with backslash-escaped characters replaced +as specified by the ANSI C standard. Backslash escape sequences, if +present, are decoded as follows: + +@table @code +@item \a +alert (bell) +@item \b +backspace +@item \e +@itemx \E +an escape character (not ANSI C) +@item \f +form feed +@item \n +newline +@item \r +carriage return +@item \t +horizontal tab +@item \v +vertical tab +@item \\ +backslash +@item \' +single quote +@item \" +double quote +@item \@var{nnn} +the eight-bit character whose value is the octal value @var{nnn} +(one to three digits) +@item \x@var{HH} +the eight-bit character whose value is the hexadecimal value @var{HH} +(one or two hex digits) +@item \u@var{HHHH} +the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value +@var{HHHH} (one to four hex digits) +@item \U@var{HHHHHHHH} +the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value +@var{HHHHHHHH} (one to eight hex digits) +@item \c@var{x} +a control-@var{x} character +@end table + +@noindent +The expanded result is single-quoted, as if the dollar sign had not +been present. + +@node Locale Translation +@subsubsection Locale-Specific Translation +@cindex localization +@cindex internationalization +@cindex native languages +@cindex translation, native languages + +A double-quoted string preceded by a dollar sign (@samp{$}) will cause +the string to be translated according to the current locale. +If the current locale is @code{C} or @code{POSIX}, the dollar sign +is ignored. +If the string is translated and replaced, the replacement is +double-quoted. + +@vindex LC_MESSAGES +@vindex TEXTDOMAIN +@vindex TEXTDOMAINDIR +Some systems use the message catalog selected by the @env{LC_MESSAGES} +shell variable. Others create the name of the message catalog from the +value of the @env{TEXTDOMAIN} shell variable, possibly adding a +suffix of @samp{.mo}. If you use the @env{TEXTDOMAIN} variable, you +may need to set the @env{TEXTDOMAINDIR} variable to the location of +the message catalog files. Still others use both variables in this +fashion: +@env{TEXTDOMAINDIR}/@env{LC_MESSAGES}/LC_MESSAGES/@env{TEXTDOMAIN}.mo. + +@node Comments +@subsection Comments +@cindex comments, shell + +In a non-interactive shell, or an interactive shell in which the +@code{interactive_comments} option to the @code{shopt} +builtin is enabled (@pxref{The Shopt Builtin}), +a word beginning with @samp{#} +causes that word and all remaining characters on that line to +be ignored. An interactive shell without the @code{interactive_comments} +option enabled does not allow comments. The @code{interactive_comments} +option is on by default in interactive shells. +@xref{Interactive Shells}, for a description of what makes +a shell interactive. + +@node Shell Commands +@section Shell Commands +@cindex commands, shell + +A simple shell command such as @code{echo a b c} consists of the command +itself followed by arguments, separated by spaces. + +More complex shell commands are composed of simple commands arranged together +in a variety of ways: in a pipeline in which the output of one command +becomes the input of a second, in a loop or conditional construct, or in +some other grouping. + +@menu +* Simple Commands:: The most common type of command. +* Pipelines:: Connecting the input and output of several + commands. +* Lists:: How to execute commands sequentially. +* Compound Commands:: Shell commands for control flow. +* Coprocesses:: Two-way communication between commands. +* GNU Parallel:: Running commands in parallel. +@end menu + +@node Simple Commands +@subsection Simple Commands +@cindex commands, simple + +A simple command is the kind of command encountered most often. +It's just a sequence of words separated by @code{blank}s, terminated +by one of the shell's control operators (@pxref{Definitions}). The +first word generally specifies a command to be executed, with the +rest of the words being that command's arguments. + +The return status (@pxref{Exit Status}) of a simple command is +its exit status as provided +by the @sc{posix} 1003.1 @code{waitpid} function, or 128+@var{n} if +the command was terminated by signal @var{n}. + +@node Pipelines +@subsection Pipelines +@cindex pipeline +@cindex commands, pipelines + +A @code{pipeline} is a sequence of one or more commands separated by +one of the control operators @samp{|} or @samp{|&}. + +@rwindex time +@rwindex ! +@cindex command timing +The format for a pipeline is +@example +[time [-p]] [!] @var{command1} [ | or |& @var{command2} ] @dots{} +@end example + +@noindent +The output of each command in the pipeline is connected via a pipe +to the input of the next command. +That is, each command reads the previous command's output. This +connection is performed before any redirections specified by the +command. + +If @samp{|&} is used, @var{command1}'s standard error, in addition to +its standard output, is connected to +@var{command2}'s standard input through the pipe; +it is shorthand for @code{2>&1 |}. +This implicit redirection of the standard error to the standard output is +performed after any redirections specified by the command. + +The reserved word @code{time} causes timing statistics +to be printed for the pipeline once it finishes. +The statistics currently consist of elapsed (wall-clock) time and +user and system time consumed by the command's execution. +The @option{-p} option changes the output format to that specified +by @sc{posix}. +When the shell is in @sc{posix} mode (@pxref{Bash POSIX Mode}), +it does not recognize @code{time} as a reserved word if the next +token begins with a @samp{-}. +The @env{TIMEFORMAT} variable may be set to a format string that +specifies how the timing information should be displayed. +@xref{Bash Variables}, for a description of the available formats. +The use of @code{time} as a reserved word permits the timing of +shell builtins, shell functions, and pipelines. An external +@code{time} command cannot time these easily. + +When the shell is in @sc{posix} mode (@pxref{Bash POSIX Mode}), @code{time} +may be followed by a newline. In this case, the shell displays the +total user and system time consumed by the shell and its children. +The @env{TIMEFORMAT} variable may be used to specify the format of +the time information. + +If the pipeline is not executed asynchronously (@pxref{Lists}), the +shell waits for all commands in the pipeline to complete. + +Each command in a pipeline is executed in its own subshell +(@pxref{Command Execution Environment}). The exit +status of a pipeline is the exit status of the last command in the +pipeline, unless the @code{pipefail} option is enabled +(@pxref{The Set Builtin}). +If @code{pipefail} is enabled, the pipeline's return status is the +value of the last (rightmost) command to exit with a non-zero status, +or zero if all commands exit successfully. +If the reserved word @samp{!} precedes the pipeline, the +exit status is the logical negation of the exit status as described +above. +The shell waits for all commands in the pipeline to terminate before +returning a value. + +@node Lists +@subsection Lists of Commands +@cindex commands, lists + +A @code{list} is a sequence of one or more pipelines separated by one +of the operators @samp{;}, @samp{&}, @samp{&&}, or @samp{||}, +and optionally terminated by one of @samp{;}, @samp{&}, or a +@code{newline}. + +Of these list operators, @samp{&&} and @samp{||} +have equal precedence, followed by @samp{;} and @samp{&}, +which have equal precedence. + +A sequence of one or more newlines may appear in a @code{list} +to delimit commands, equivalent to a semicolon. + +If a command is terminated by the control operator @samp{&}, +the shell executes the command asynchronously in a subshell. +This is known as executing the command in the @var{background}. +The shell does not wait for the command to finish, and the return +status is 0 (true). +When job control is not active (@pxref{Job Control}), +the standard input for asynchronous commands, in the absence of any +explicit redirections, is redirected from @code{/dev/null}. + +Commands separated by a @samp{;} are executed sequentially; the shell +waits for each command to terminate in turn. The return status is the +exit status of the last command executed. + +@sc{and} and @sc{or} lists are sequences of one or more pipelines +separated by the control operators @samp{&&} and @samp{||}, +respectively. @sc{and} and @sc{or} lists are executed with left +associativity. + +An @sc{and} list has the form +@example +@var{command1} && @var{command2} +@end example + +@noindent +@var{command2} is executed if, and only if, @var{command1} +returns an exit status of zero. + +An @sc{or} list has the form +@example +@var{command1} || @var{command2} +@end example + +@noindent +@var{command2} is executed if, and only if, @var{command1} +returns a non-zero exit status. + +The return status of +@sc{and} and @sc{or} lists is the exit status of the last command +executed in the list. + +@node Compound Commands +@subsection Compound Commands +@cindex commands, compound + +@menu +* Looping Constructs:: Shell commands for iterative action. +* Conditional Constructs:: Shell commands for conditional execution. +* Command Grouping:: Ways to group commands. +@end menu + +Compound commands are the shell programming constructs. +Each construct begins with a reserved word or control operator and is +terminated by a corresponding reserved word or operator. +Any redirections (@pxref{Redirections}) associated with a compound command +apply to all commands within that compound command unless explicitly overridden. + +In most cases a list of commands in a compound command's description may be +separated from the rest of the command by one or more newlines, and may be +followed by a newline in place of a semicolon. + +Bash provides looping constructs, conditional commands, and mechanisms +to group commands and execute them as a unit. + +@node Looping Constructs +@subsubsection Looping Constructs +@cindex commands, looping + +Bash supports the following looping constructs. + +Note that wherever a @samp{;} appears in the description of a +command's syntax, it may be replaced with one or more newlines. + +@table @code +@item until +@rwindex until +@rwindex do +@rwindex done +The syntax of the @code{until} command is: + +@example +until @var{test-commands}; do @var{consequent-commands}; done +@end example + +Execute @var{consequent-commands} as long as +@var{test-commands} has an exit status which is not zero. +The return status is the exit status of the last command executed +in @var{consequent-commands}, or zero if none was executed. + +@item while +@rwindex while +The syntax of the @code{while} command is: + +@example +while @var{test-commands}; do @var{consequent-commands}; done +@end example + +Execute @var{consequent-commands} as long as +@var{test-commands} has an exit status of zero. +The return status is the exit status of the last command executed +in @var{consequent-commands}, or zero if none was executed. + +@item for +@rwindex for +The syntax of the @code{for} command is: + +@example +for @var{name} [ [in [@var{words} @dots{}] ] ; ] do @var{commands}; done +@end example + +Expand @var{words}, and execute @var{commands} once for each member +in the resultant list, with @var{name} bound to the current member. +If @samp{in @var{words}} is not present, the @code{for} command +executes the @var{commands} once for each positional parameter that is +set, as if @samp{in "$@@"} had been specified +(@pxref{Special Parameters}). +The return status is the exit status of the last command that executes. +If there are no items in the expansion of @var{words}, no commands are +executed, and the return status is zero. + +An alternate form of the @code{for} command is also supported: + +@example +for (( @var{expr1} ; @var{expr2} ; @var{expr3} )) ; do @var{commands} ; done +@end example + +First, the arithmetic expression @var{expr1} is evaluated according +to the rules described below (@pxref{Shell Arithmetic}). +The arithmetic expression @var{expr2} is then evaluated repeatedly +until it evaluates to zero. +Each time @var{expr2} evaluates to a non-zero value, @var{commands} are +executed and the arithmetic expression @var{expr3} is evaluated. +If any expression is omitted, it behaves as if it evaluates to 1. +The return value is the exit status of the last command in @var{commands} +that is executed, or false if any of the expressions is invalid. +@end table + +The @code{break} and @code{continue} builtins (@pxref{Bourne Shell Builtins}) +may be used to control loop execution. + +@node Conditional Constructs +@subsubsection Conditional Constructs +@cindex commands, conditional + +@table @code +@item if +@rwindex if +@rwindex then +@rwindex else +@rwindex elif +@rwindex fi +The syntax of the @code{if} command is: + +@example +if @var{test-commands}; then + @var{consequent-commands}; +[elif @var{more-test-commands}; then + @var{more-consequents};] +[else @var{alternate-consequents};] +fi +@end example + +The @var{test-commands} list is executed, and if its return status is zero, +the @var{consequent-commands} list is executed. +If @var{test-commands} returns a non-zero status, each @code{elif} list +is executed in turn, and if its exit status is zero, +the corresponding @var{more-consequents} is executed and the +command completes. +If @samp{else @var{alternate-consequents}} is present, and +the final command in the final @code{if} or @code{elif} clause +has a non-zero exit status, then @var{alternate-consequents} is executed. +The return status is the exit status of the last command executed, or +zero if no condition tested true. + +@item case +@rwindex case +@rwindex in +@rwindex esac +The syntax of the @code{case} command is: + +@example +case @var{word} in [ [(] @var{pattern} [| @var{pattern}]@dots{}) @var{command-list} ;;]@dots{} esac +@end example + +@code{case} will selectively execute the @var{command-list} corresponding to +the first @var{pattern} that matches @var{word}. +If the shell option @code{nocasematch} +(see the description of @code{shopt} in @ref{The Shopt Builtin}) +is enabled, the match is performed without regard to the case +of alphabetic characters. +The @samp{|} is used to separate multiple patterns, and the @samp{)} +operator terminates a pattern list. +A list of patterns and an associated command-list is known +as a @var{clause}. + +Each clause must be terminated with @samp{;;}, @samp{;&}, or @samp{;;&}. +The @var{word} undergoes tilde expansion, parameter expansion, command +substitution, arithmetic expansion, and quote removal before matching is +attempted. Each @var{pattern} undergoes tilde expansion, parameter +expansion, command substitution, and arithmetic expansion. + +There may be an arbitrary number of @code{case} clauses, each terminated +by a @samp{;;}, @samp{;&}, or @samp{;;&}. +The first pattern that matches determines the +command-list that is executed. +It's a common idiom to use @samp{*} as the final pattern to define the +default case, since that pattern will always match. + +Here is an example using @code{case} in a script that could be used to +describe one interesting feature of an animal: + +@example +echo -n "Enter the name of an animal: " +read ANIMAL +echo -n "The $ANIMAL has " +case $ANIMAL in + horse | dog | cat) echo -n "four";; + man | kangaroo ) echo -n "two";; + *) echo -n "an unknown number of";; +esac +echo " legs." +@end example + +@noindent + +If the @samp{;;} operator is used, no subsequent matches are attempted after +the first pattern match. +Using @samp{;&} in place of @samp{;;} causes execution to continue with +the @var{command-list} associated with the next clause, if any. +Using @samp{;;&} in place of @samp{;;} causes the shell to test the patterns +in the next clause, if any, and execute any associated @var{command-list} +on a successful match. + +The return status is zero if no @var{pattern} is matched. Otherwise, the +return status is the exit status of the @var{command-list} executed. + +@item select +@rwindex select + +The @code{select} construct allows the easy generation of menus. +It has almost the same syntax as the @code{for} command: + +@example +select @var{name} [in @var{words} @dots{}]; do @var{commands}; done +@end example + +The list of words following @code{in} is expanded, generating a list +of items. The set of expanded words is printed on the standard +error output stream, each preceded by a number. If the +@samp{in @var{words}} is omitted, the positional parameters are printed, +as if @samp{in "$@@"} had been specified. +The @env{PS3} prompt is then displayed and a line is read from the +standard input. +If the line consists of a number corresponding to one of the displayed +words, then the value of @var{name} is set to that word. +If the line is empty, the words and prompt are displayed again. +If @code{EOF} is read, the @code{select} command completes. +Any other value read causes @var{name} to be set to null. +The line read is saved in the variable @env{REPLY}. + +The @var{commands} are executed after each selection until a +@code{break} command is executed, at which +point the @code{select} command completes. + +Here is an example that allows the user to pick a filename from the +current directory, and displays the name and index of the file +selected. + +@example +select fname in *; +do + echo you picked $fname \($REPLY\) + break; +done +@end example + +@item ((@dots{})) +@example +(( @var{expression} )) +@end example + +The arithmetic @var{expression} is evaluated according to the rules +described below (@pxref{Shell Arithmetic}). +If the value of the expression is non-zero, the return status is 0; +otherwise the return status is 1. This is exactly equivalent to +@example +let "@var{expression}" +@end example +@noindent +@xref{Bash Builtins}, for a full description of the @code{let} builtin. + +@item [[@dots{}]] +@rwindex [[ +@rwindex ]] +@example +[[ @var{expression} ]] +@end example + +Return a status of 0 or 1 depending on the evaluation of +the conditional expression @var{expression}. +Expressions are composed of the primaries described below in +@ref{Bash Conditional Expressions}. +Word splitting and filename expansion are not performed on the words +between the @code{[[} and @code{]]}; tilde expansion, parameter and +variable expansion, arithmetic expansion, command substitution, process +substitution, and quote removal are performed. +Conditional operators such as @samp{-f} must be unquoted to be recognized +as primaries. + +When used with @code{[[}, the @samp{<} and @samp{>} operators sort +lexicographically using the current locale. + +When the @samp{==} and @samp{!=} operators are used, the string to the +right of the operator is considered a pattern and matched according +to the rules described below in @ref{Pattern Matching}, +as if the @code{extglob} shell option were enabled. +The @samp{=} operator is identical to @samp{==}. +If the shell option @code{nocasematch} +(see the description of @code{shopt} in @ref{The Shopt Builtin}) +is enabled, the match is performed without regard to the case +of alphabetic characters. +The return value is 0 if the string matches (@samp{==}) or does not +match (@samp{!=})the pattern, and 1 otherwise. +Any part of the pattern may be quoted to force the quoted portion +to be matched as a string. + +An additional binary operator, @samp{=~}, is available, with the same +precedence as @samp{==} and @samp{!=}. +When it is used, the string to the right of the operator is considered +an extended regular expression and matched accordingly (as in @i{regex}3)). +The return value is 0 if the string matches +the pattern, and 1 otherwise. +If the regular expression is syntactically incorrect, the conditional +expression's return value is 2. +If the shell option @code{nocasematch} +(see the description of @code{shopt} in @ref{The Shopt Builtin}) +is enabled, the match is performed without regard to the case +of alphabetic characters. +Any part of the pattern may be quoted to force the quoted portion +to be matched as a string. +Bracket expressions in regular expressions must be treated carefully, +since normal quoting characters lose their meanings between brackets. +If the pattern is stored in a shell variable, quoting the variable +expansion forces the entire pattern to be matched as a string. +Substrings matched by parenthesized subexpressions within the regular +expression are saved in the array variable @code{BASH_REMATCH}. +The element of @code{BASH_REMATCH} with index 0 is the portion of the string +matching the entire regular expression. +The element of @code{BASH_REMATCH} with index @var{n} is the portion of the +string matching the @var{n}th parenthesized subexpression. + +For example, the following will match a line +(stored in the shell variable @var{line}) +if there is a sequence of characters in the value consisting of +any number, including zero, of +space characters, zero or one instances of @samp{a}, then a @samp{b}: +@example +[[ $line =~ [[:space:]]*(a)?b ]] +@end example + +@noindent +That means values like @samp{aab} and @samp{ aaaaaab} will match, as +will a line containing a @samp{b} anywhere in its value. + +Storing the regular expression in a shell variable is often a useful +way to avoid problems with quoting characters that are special to the +shell. +It is sometimes difficult to specify a regular expression literally +without using quotes, or to keep track of the quoting used by regular +expressions while paying attention to the shell's quote removal. +Using a shell variable to store the pattern decreases these problems. +For example, the following is equivalent to the above: +@example +pattern='[[:space:]]*(a)?b' +[[ $line =~ $pattern ]] +@end example + +@noindent +If you want to match a character that's special to the regular expression +grammar, it has to be quoted to remove its special meaning. +This means that in the pattern @samp{xxx.txt}, the @samp{.} matches any +character in the string (its usual regular expression meaning), but in the +pattern @samp{"xxx.txt"} it can only match a literal @samp{.}. +Shell programmers should take special care with backslashes, since backslashes +are used both by the shell and regular expressions to remove the special +meaning from the following character. +The following two sets of commands are @emph{not} equivalent: +@example +pattern='\.' + +[[ . =~ $pattern ]] +[[ . =~ \. ]] + +[[ . =~ "$pattern" ]] +[[ . =~ '\.' ]] +@end example + +@noindent +The first two matches will succeed, but the second two will not, because +in the second two the backslash will be part of the pattern to be matched. +In the first two examples, the backslash removes the special meaning from +@samp{.}, so the literal @samp{.} matches. +If the string in the first examples were anything other than @samp{.}, say +@samp{a}, the pattern would not match, because the quoted @samp{.} in the +pattern loses its special meaning of matching any single character. + +Expressions may be combined using the following operators, listed +in decreasing order of precedence: + +@table @code +@item ( @var{expression} ) +Returns the value of @var{expression}. +This may be used to override the normal precedence of operators. + +@item ! @var{expression} +True if @var{expression} is false. + +@item @var{expression1} && @var{expression2} +True if both @var{expression1} and @var{expression2} are true. + +@item @var{expression1} || @var{expression2} +True if either @var{expression1} or @var{expression2} is true. +@end table + +@noindent +The @code{&&} and @code{||} operators do not evaluate @var{expression2} if the +value of @var{expression1} is sufficient to determine the return +value of the entire conditional expression. +@end table + +@node Command Grouping +@subsubsection Grouping Commands +@cindex commands, grouping + +Bash provides two ways to group a list of commands to be executed +as a unit. When commands are grouped, redirections may be applied +to the entire command list. For example, the output of all the +commands in the list may be redirected to a single stream. + +@table @code +@item () +@example +( @var{list} ) +@end example + +Placing a list of commands between parentheses causes a subshell +environment to be created (@pxref{Command Execution Environment}), and each +of the commands in @var{list} to be executed in that subshell. Since the +@var{list} is executed in a subshell, variable assignments do not remain in +effect after the subshell completes. + +@item @{@} +@rwindex @{ +@rwindex @} +@example +@{ @var{list}; @} +@end example + +Placing a list of commands between curly braces causes the list to +be executed in the current shell context. No subshell is created. +The semicolon (or newline) following @var{list} is required. +@end table + +In addition to the creation of a subshell, there is a subtle difference +between these two constructs due to historical reasons. The braces +are @code{reserved words}, so they must be separated from the @var{list} +by @code{blank}s or other shell metacharacters. +The parentheses are @code{operators}, and are +recognized as separate tokens by the shell even if they are not separated +from the @var{list} by whitespace. + +The exit status of both of these constructs is the exit status of +@var{list}. + +@node Coprocesses +@subsection Coprocesses +@cindex coprocess + +A @code{coprocess} is a shell command preceded by the @code{coproc} +reserved word. +A coprocess is executed asynchronously in a subshell, as if the command +had been terminated with the @samp{&} control operator, with a two-way pipe +established between the executing shell and the coprocess. + +The format for a coprocess is: +@example +coproc [@var{NAME}] @var{command} [@var{redirections}] +@end example + +@noindent +This creates a coprocess named @var{NAME}. +If @var{NAME} is not supplied, the default name is @var{COPROC}. +@var{NAME} must not be supplied if @var{command} is a simple +command (@pxref{Simple Commands}); otherwise, it is interpreted as +the first word of the simple command. + +When the coprocess is executed, the shell creates an array variable +(@pxref{Arrays}) +named @env{NAME} in the context of the executing shell. +The standard output of @var{command} +is connected via a pipe to a file descriptor in the executing shell, +and that file descriptor is assigned to @env{NAME}[0]. +The standard input of @var{command} +is connected via a pipe to a file descriptor in the executing shell, +and that file descriptor is assigned to @env{NAME}[1]. +This pipe is established before any redirections specified by the +command (@pxref{Redirections}). +The file descriptors can be utilized as arguments to shell commands +and redirections using standard word expansions. +The file descriptors are not available in subshells. + +The process ID of the shell spawned to execute the coprocess is +available as the value of the variable @env{NAME}_PID. +The @code{wait} +builtin command may be used to wait for the coprocess to terminate. + +Since the coprocess is created as an asynchronous command, +the @code{coproc} command always returns success. +The return status of a coprocess is the exit status of @var{command}. + +@node GNU Parallel +@subsection GNU Parallel + +There are ways to run commands in parallel that are not built into Bash. +GNU Parallel is a tool to do just that. + +GNU Parallel, as its name suggests, can be used to build and run commands +in parallel. You may run the same command with different arguments, whether +they are filenames, usernames, hostnames, or lines read from files. GNU +Parallel provides shorthand references to many of the most common operations +(input lines, various portions of the input line, different ways to specify +the input source, and so on). Parallel can replace @code{xargs} or feed +commands from its input sources to several different instances of Bash. + +For a complete description, refer to the GNU Parallel documentation. A few +examples should provide a brief introduction to its use. + +For example, it is easy to replace @code{xargs} to gzip all html files in the +current directory and its subdirectories: +@example +find . -type f -name '*.html' -print | parallel gzip +@end example +@noindent +If you need to protect special characters such as newlines in file names, +use find's @option{-print0} option and parallel's @option{-0} option. + +You can use Parallel to move files from the current directory when the +number of files is too large to process with one @code{mv} invocation: +@example +ls | parallel mv @{@} destdir +@end example + +As you can see, the @{@} is replaced with each line read from standard input. +While using @code{ls} will work in most instances, it is not sufficient to +deal with all filenames. +If you need to accommodate special characters in filenames, you can use + +@example +find . -depth 1 \! -name '.*' -print0 | parallel -0 mv @{@} destdir +@end example + +@noindent +as alluded to above. + +This will run as many @code{mv} commands as there are files in the current +directory. +You can emulate a parallel @code{xargs} by adding the @option{-X} option: +@example +find . -depth 1 \! -name '.*' -print0 | parallel -0 -X mv @{@} destdir +@end example + +GNU Parallel can replace certain common idioms that operate on lines read +from a file (in this case, filenames listed one per line): +@example + while IFS= read -r x; do + do-something1 "$x" "config-$x" + do-something2 < "$x" + done < file | process-output +@end example + +@noindent +with a more compact syntax reminiscent of lambdas: +@example +cat list | parallel "do-something1 @{@} config-@{@} ; do-something2 < @{@}" | process-output +@end example + +Parallel provides a built-in mechanism to remove filename extensions, which +lends itself to batch file transformations or renaming: +@example +ls *.gz | parallel -j+0 "zcat @{@} | bzip2 >@{.@}.bz2 && rm @{@}" +@end example +@noindent +This will recompress all files in the current directory with names ending +in .gz using bzip2, running one job per CPU (-j+0) in parallel. +(We use @code{ls} for brevity here; using @code{find} as above is more +robust in the face of filenames containing unexpected characters.) +Parallel can take arguments from the command line; the above can also be +written as + +@example +parallel "zcat @{@} | bzip2 >@{.@}.bz2 && rm @{@}" ::: *.gz +@end example + +If a command generates output, you may want to preserve the input order in +the output. For instance, the following command +@example +@{ echo foss.org.my ; echo debian.org; echo freenetproject.org; @} | parallel traceroute +@end example +@noindent +will display as output the traceroute invocation that finishes first. +Adding the @option{-k} option +@example +@{ echo foss.org.my ; echo debian.org; echo freenetproject.org; @} | parallel -k traceroute +@end example +@noindent +will ensure that the output of @code{traceroute foss.org.my} is displayed first. + +Finally, Parallel can be used to run a sequence of shell commands in parallel, +similar to @samp{cat file | bash}. +It is not uncommon to take a list of filenames, create a series of shell +commands to operate on them, and feed that list of commnds to a shell. +Parallel can speed this up. Assuming that @file{file} contains a list of +shell commands, one per line, + +@example +parallel -j 10 < file +@end example + +@noindent +will evaluate the commands using the shell (since no explicit command is +supplied as an argument), in blocks of ten shell jobs at a time. + +@node Shell Functions +@section Shell Functions +@cindex shell function +@cindex functions, shell + +Shell functions are a way to group commands for later execution +using a single name for the group. They are executed just like +a "regular" command. +When the name of a shell function is used as a simple command name, +the list of commands associated with that function name is executed. +Shell functions are executed in the current +shell context; no new process is created to interpret them. + +Functions are declared using this syntax: +@rwindex function +@example +@var{name} () @var{compound-command} [ @var{redirections} ] +@end example + +or + +@example +function @var{name} [()] @var{compound-command} [ @var{redirections} ] +@end example + +This defines a shell function named @var{name}. The reserved +word @code{function} is optional. +If the @code{function} reserved +word is supplied, the parentheses are optional. +The @var{body} of the function is the compound command +@var{compound-command} (@pxref{Compound Commands}). +That command is usually a @var{list} enclosed between @{ and @}, but +may be any compound command listed above, +with one exception: If the @code{function} reserved word is used, but the +parentheses are not supplied, the braces are required. +@var{compound-command} is executed whenever @var{name} is specified as the +name of a command. +When the shell is in @sc{posix} mode (@pxref{Bash POSIX Mode}), +@var{name} may not be the same as one of the special builtins +(@pxref{Special Builtins}). +Any redirections (@pxref{Redirections}) associated with the shell function +are performed when the function is executed. + +A function definition may be deleted using the @option{-f} option to the +@code{unset} builtin (@pxref{Bourne Shell Builtins}). + +The exit status of a function definition is zero unless a syntax error +occurs or a readonly function with the same name already exists. +When executed, the exit status of a function is the exit status of the +last command executed in the body. + +Note that for historical reasons, in the most common usage the curly braces +that surround the body of the function must be separated from the body by +@code{blank}s or newlines. +This is because the braces are reserved words and are only recognized +as such when they are separated from the command list +by whitespace or another shell metacharacter. +Also, when using the braces, the @var{list} must be terminated by a semicolon, +a @samp{&}, or a newline. + +When a function is executed, the arguments to the +function become the positional parameters +during its execution (@pxref{Positional Parameters}). +The special parameter @samp{#} that expands to the number of +positional parameters is updated to reflect the change. +Special parameter @code{0} is unchanged. +The first element of the @env{FUNCNAME} variable is set to the +name of the function while the function is executing. + +All other aspects of the shell execution +environment are identical between a function and its caller +with these exceptions: +the @env{DEBUG} and @env{RETURN} traps +are not inherited unless the function has been given the +@code{trace} attribute using the @code{declare} builtin or +the @code{-o functrace} option has been enabled with +the @code{set} builtin, +(in which case all functions inherit the @env{DEBUG} and @env{RETURN} traps), +and the @env{ERR} trap is not inherited unless the @code{-o errtrace} +shell option has been enabled. +@xref{Bourne Shell Builtins}, for the description of the +@code{trap} builtin. + +The @env{FUNCNEST} variable, if set to a numeric value greater +than 0, defines a maximum function nesting level. Function +invocations that exceed the limit cause the entire command to +abort. + +If the builtin command @code{return} +is executed in a function, the function completes and +execution resumes with the next command after the function +call. +Any command associated with the @code{RETURN} trap is executed +before execution resumes. +When a function completes, the values of the +positional parameters and the special parameter @samp{#} +are restored to the values they had prior to the function's +execution. If a numeric argument is given to @code{return}, +that is the function's return status; otherwise the function's +return status is the exit status of the last command executed +before the @code{return}. + +Variables local to the function may be declared with the +@code{local} builtin. These variables are visible only to +the function and the commands it invokes. + +Function names and definitions may be listed with the +@option{-f} option to the @code{declare} (@code{typeset}) +builtin command (@pxref{Bash Builtins}). +The @option{-F} option to @code{declare} or @code{typeset} +will list the function names only +(and optionally the source file and line number, if the @code{extdebug} +shell option is enabled). +Functions may be exported so that subshells +automatically have them defined with the +@option{-f} option to the @code{export} builtin +(@pxref{Bourne Shell Builtins}). +Note that shell functions and variables with the same name may result +in multiple identically-named entries in the environment passed to the +shell's children. +Care should be taken in cases where this may cause a problem. + +Functions may be recursive. +The @code{FUNCNEST} variable may be used to limit the depth of the +function call stack and restrict the number of function invocations. +By default, no limit is placed on the number of recursive calls. + +@node Shell Parameters +@section Shell Parameters +@cindex parameters +@cindex variable, shell +@cindex shell variable + +@menu +* Positional Parameters:: The shell's command-line arguments. +* Special Parameters:: Parameters denoted by special characters. +@end menu + +A @var{parameter} is an entity that stores values. +It can be a @code{name}, a number, or one of the special characters +listed below. +A @var{variable} is a parameter denoted by a @code{name}. +A variable has a @var{value} and zero or more @var{attributes}. +Attributes are assigned using the @code{declare} builtin command +(see the description of the @code{declare} builtin in @ref{Bash Builtins}). + +A parameter is set if it has been assigned a value. The null string is +a valid value. Once a variable is set, it may be unset only by using +the @code{unset} builtin command. + +A variable may be assigned to by a statement of the form +@example +@var{name}=[@var{value}] +@end example +@noindent +If @var{value} +is not given, the variable is assigned the null string. All +@var{value}s undergo tilde expansion, parameter and variable expansion, +command substitution, arithmetic expansion, and quote +removal (detailed below). If the variable has its @code{integer} +attribute set, then @var{value} +is evaluated as an arithmetic expression even if the @code{$((@dots{}))} +expansion is not used (@pxref{Arithmetic Expansion}). +Word splitting is not performed, with the exception +of @code{"$@@"} as explained below. +Filename expansion is not performed. +Assignment statements may also appear as arguments to the +@code{alias}, +@code{declare}, @code{typeset}, @code{export}, @code{readonly}, +and @code{local} builtin commands (@var{declaration} commands). +When in @sc{posix} mode (@pxref{Bash POSIX Mode}), these builtins may appear +in a command after one or more instances of the @code{command} builtin +and retain these assignment statement properties. + +In the context where an assignment statement is assigning a value +to a shell variable or array index (@pxref{Arrays}), the @samp{+=} +operator can be used to +append to or add to the variable's previous value. +This includes arguments to builtin commands such as @code{declare} that +accept assignment statements (@var{declaration} commands). +When @samp{+=} is applied to a variable for which the @var{integer} attribute +has been set, @var{value} is evaluated as an arithmetic expression and +added to the variable's current value, which is also evaluated. +When @samp{+=} is applied to an array variable using compound assignment +(@pxref{Arrays}), the +variable's value is not unset (as it is when using @samp{=}), and new +values are appended to the array beginning at one greater than the array's +maximum index (for indexed arrays), or added as additional key-value pairs +in an associative array. +When applied to a string-valued variable, @var{value} is expanded and +appended to the variable's value. + +A variable can be assigned the @var{nameref} attribute using the +@option{-n} option to the \fBdeclare\fP or \fBlocal\fP builtin commands +(@pxref{Bash Builtins}) +to create a @var{nameref}, or a reference to another variable. +This allows variables to be manipulated indirectly. +Whenever the nameref variable is referenced, assigned to, unset, or has +its attributes modified (other than the nameref attribute itself), the +operation is actually performed on the variable specified by the nameref +variable's value. +A nameref is commonly used within shell functions to refer to a variable +whose name is passed as an argument to the function. +For instance, if a variable name is passed to a shell function as its first +argument, running +@example +declare -n ref=$1 +@end example +@noindent +inside the function creates a nameref variable @var{ref} whose value is +the variable name passed as the first argument. +References and assignments to @var{ref}, and changes to its attributes, +are treated as references, assignments, and attribute modifications +to the variable whose name was passed as @code{$1}. + +If the control variable in a @code{for} loop has the nameref attribute, +the list of words can be a list of shell variables, and a name reference +will be established for each word in the list, in turn, when the loop is +executed. +Array variables cannot be given the nameref attribute. +However, nameref variables can reference array variables and subscripted +array variables. +Namerefs can be unset using the @option{-n} option to the @code{unset} builtin +(@pxref{Bourne Shell Builtins}). +Otherwise, if @code{unset} is executed with the name of a nameref variable +as an argument, the variable referenced by the nameref variable will be unset. + +@node Positional Parameters +@subsection Positional Parameters +@cindex parameters, positional + +A @var{positional parameter} is a parameter denoted by one or more +digits, other than the single digit @code{0}. Positional parameters are +assigned from the shell's arguments when it is invoked, +and may be reassigned using the @code{set} builtin command. +Positional parameter @code{N} may be referenced as @code{$@{N@}}, or +as @code{$N} when @code{N} consists of a single digit. +Positional parameters may not be assigned to with assignment statements. +The @code{set} and @code{shift} builtins are used to set and +unset them (@pxref{Shell Builtin Commands}). +The positional parameters are +temporarily replaced when a shell function is executed +(@pxref{Shell Functions}). + +When a positional parameter consisting of more than a single +digit is expanded, it must be enclosed in braces. + +@node Special Parameters +@subsection Special Parameters +@cindex parameters, special + +The shell treats several parameters specially. These parameters may +only be referenced; assignment to them is not allowed. + +@vtable @code + +@item * +@vindex $* +($*) Expands to the positional parameters, starting from one. +When the expansion is not within double quotes, each positional parameter +expands to a separate word. +In contexts where it is performed, those words +are subject to further word splitting and pathname expansion. +When the expansion occurs within double quotes, it expands to a single word +with the value of each parameter separated by the first character +of the @env{IFS} +special variable. That is, @code{"$*"} is equivalent +to @code{"$1@var{c}$2@var{c}@dots{}"}, where @var{c} +is the first character of the value of the @code{IFS} +variable. +If @env{IFS} is unset, the parameters are separated by spaces. +If @env{IFS} is null, the parameters are joined without intervening +separators. + +@item @@ +@vindex $@@ +($@@) Expands to the positional parameters, starting from one. When the +expansion occurs within double quotes, each parameter expands to a +separate word. That is, @code{"$@@"} is equivalent to +@code{"$1" "$2" @dots{}}. +If the double-quoted expansion occurs within a word, the expansion of +the first parameter is joined with the beginning part of the original +word, and the expansion of the last parameter is joined with the last +part of the original word. +When there are no positional parameters, @code{"$@@"} and +@code{$@@} +expand to nothing (i.e., they are removed). + +@item # +@vindex $# +($#) Expands to the number of positional parameters in decimal. + +@item ? +@vindex $? +($?) Expands to the exit status of the most recently executed foreground +pipeline. + +@item - +@vindex $- +($-, a hyphen.) Expands to the current option flags as specified upon +invocation, by the @code{set} +builtin command, or those set by the shell itself +(such as the @option{-i} option). + +@item $ +@vindex $$ +($$) Expands to the process @sc{id} of the shell. In a @code{()} subshell, it +expands to the process @sc{id} of the invoking shell, not the subshell. + +@item ! +@vindex $! +($!) Expands to the process @sc{id} of the job most recently placed into the +background, whether executed as an asynchronous command or using +the @code{bg} builtin (@pxref{Job Control Builtins}). + +@item 0 +@vindex $0 +($0) Expands to the name of the shell or shell script. This is set at +shell initialization. If Bash is invoked with a file of commands +(@pxref{Shell Scripts}), @code{$0} is set to the name of that file. +If Bash is started with the @option{-c} option (@pxref{Invoking Bash}), +then @code{$0} is set to the first argument after the string to be +executed, if one is present. Otherwise, it is set +to the filename used to invoke Bash, as given by argument zero. + +@item _ +@vindex $_ +($_, an underscore.) +At shell startup, set to the absolute pathname used to invoke the +shell or shell script being executed as passed in the environment +or argument list. +Subsequently, expands to the last argument to the previous command, +after expansion. +Also set to the full pathname used to invoke each command executed +and placed in the environment exported to that command. +When checking mail, this parameter holds the name of the mail file. +@end vtable + +@node Shell Expansions +@section Shell Expansions +@cindex expansion + +Expansion is performed on the command line after it has been split into +@code{token}s. There are seven kinds of expansion performed: + +@itemize @bullet +@item brace expansion +@item tilde expansion +@item parameter and variable expansion +@item command substitution +@item arithmetic expansion +@item word splitting +@item filename expansion +@end itemize + +@menu +* Brace Expansion:: Expansion of expressions within braces. +* Tilde Expansion:: Expansion of the ~ character. +* Shell Parameter Expansion:: How Bash expands variables to their values. +* Command Substitution:: Using the output of a command as an argument. +* Arithmetic Expansion:: How to use arithmetic in shell expansions. +* Process Substitution:: A way to write and read to and from a + command. +* Word Splitting:: How the results of expansion are split into separate + arguments. +* Filename Expansion:: A shorthand for specifying filenames matching patterns. +* Quote Removal:: How and when quote characters are removed from + words. +@end menu + +The order of expansions is: +brace expansion; +tilde expansion, parameter and variable expansion, arithmetic expansion, +and command substitution (done in a left-to-right fashion); +word splitting; +and filename expansion. + +On systems that can support it, there is an additional expansion +available: @var{process substitution}. +This is performed at the +same time as tilde, parameter, variable, and arithmetic expansion and +command substitution. + +Only brace expansion, word splitting, and filename 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 of +@code{"$@@"} (@pxref{Special Parameters}) and @code{"$@{@var{name}[@@]@}"} +(@pxref{Arrays}). + +After all expansions, @code{quote removal} (@pxref{Quote Removal}) +is performed. + +@node Brace Expansion +@subsection Brace Expansion +@cindex brace expansion +@cindex expansion, brace + +Brace expansion is a mechanism by which arbitrary strings may be generated. +This mechanism is similar to +@var{filename expansion} (@pxref{Filename Expansion}), +but the filenames generated need not exist. +Patterns to be brace expanded take the form of an optional @var{preamble}, +followed by either a series of comma-separated strings or a sequence expression +between a pair of braces, +followed by an optional @var{postscript}. +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, +@example +bash$ echo a@{d,c,b@}e +ade ace abe +@end example + +A sequence expression takes the form @code{@{@var{x}..@var{y}[..@var{incr}]@}}, +where @var{x} and @var{y} are either integers or single characters, +and @var{incr}, an optional increment, is an integer. +When integers are supplied, the expression expands to each number between +@var{x} and @var{y}, inclusive. +Supplied integers may be prefixed with @samp{0} to force each term to have the +same width. +When either @var{x} or @var{y} begins with a zero, the shell +attempts to force all generated terms to contain the same number of digits, +zero-padding where necessary. +When characters are supplied, the expression expands to each character +lexicographically between @var{x} and @var{y}, inclusive, +using the default C locale. +Note that both @var{x} and @var{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 characters special to other expansions are preserved +in the result. It is strictly textual. Bash +does not apply any syntactic interpretation to the context of the +expansion or the text between the braces. +To avoid conflicts with parameter expansion, the string @samp{$@{} +is not considered eligible for brace expansion. + +A correctly-formed brace expansion must contain unquoted opening +and closing braces, and at least one unquoted comma or a valid +sequence expression. +Any incorrectly formed brace expansion is left unchanged. + +A @{ or @samp{,} may be quoted with a backslash to prevent its +being considered part of a brace expression. +To avoid conflicts with parameter expansion, the string @samp{$@{} +is not considered eligible for brace expansion. + +This construct is typically used as shorthand when the common +prefix of the strings to be generated is longer than in the +above example: +@example +mkdir /usr/local/src/bash/@{old,new,dist,bugs@} +@end example +or +@example +chown root /usr/@{ucb/@{ex,edit@},lib/@{ex?.?*,how_ex@}@} +@end example + +@node Tilde Expansion +@subsection Tilde Expansion +@cindex tilde expansion +@cindex expansion, tilde + +If a word begins with an unquoted tilde character (@samp{~}), all of the +characters up to the first unquoted slash (or all characters, +if there is no unquoted slash) are considered a @var{tilde-prefix}. +If none of the characters in the tilde-prefix are quoted, the +characters in the tilde-prefix following the tilde are treated as a +possible @var{login name}. +If this login name is the null string, the tilde is replaced with the +value of the @env{HOME} shell variable. +If @env{HOME} is unset, the home directory of the user executing the +shell is substituted instead. +Otherwise, the tilde-prefix is replaced with the home directory +associated with the specified login name. + +If the tilde-prefix is @samp{~+}, the value of +the shell variable @env{PWD} replaces the tilde-prefix. +If the tilde-prefix is @samp{~-}, the value of the shell variable +@env{OLDPWD}, if it is set, is substituted. + +If the characters following the tilde in the tilde-prefix consist of a +number @var{N}, optionally prefixed by a @samp{+} or a @samp{-}, +the tilde-prefix is replaced with the +corresponding element from the directory stack, as it would be displayed +by the @code{dirs} builtin invoked with the characters following tilde +in the tilde-prefix as an argument (@pxref{The Directory Stack}). +If the tilde-prefix, sans the tilde, consists of a number without a +leading @samp{+} or @samp{-}, @samp{+} is assumed. + +If the login name is invalid, or the tilde expansion fails, the word is +left unchanged. + +Each variable assignment is checked for unquoted tilde-prefixes immediately +following a @samp{:} or the first @samp{=}. +In these cases, tilde expansion is also performed. +Consequently, one may use filenames with tildes in assignments to +@env{PATH}, @env{MAILPATH}, and @env{CDPATH}, +and the shell assigns the expanded value. + +The following table shows how Bash treats unquoted tilde-prefixes: + +@table @code +@item ~ +The value of @code{$HOME} +@item ~/foo +@file{$HOME/foo} + +@item ~fred/foo +The subdirectory @code{foo} of the home directory of the user +@code{fred} + +@item ~+/foo +@file{$PWD/foo} + +@item ~-/foo +@file{$@{OLDPWD-'~-'@}/foo} + +@item ~@var{N} +The string that would be displayed by @samp{dirs +@var{N}} + +@item ~+@var{N} +The string that would be displayed by @samp{dirs +@var{N}} + +@item ~-@var{N} +The string that would be displayed by @samp{dirs -@var{N}} +@end table + +@node Shell Parameter Expansion +@subsection Shell Parameter Expansion +@cindex parameter expansion +@cindex expansion, parameter + +The @samp{$} character introduces parameter expansion, +command substitution, or arithmetic expansion. The parameter name +or symbol to be expanded may be enclosed in braces, which +are optional but serve to protect the variable to be expanded from +characters immediately following it which could be +interpreted as part of the name. + +When braces are used, the matching ending brace is the first @samp{@}} +not escaped by a backslash or within a quoted string, and not within an +embedded arithmetic expansion, command substitution, or parameter +expansion. + +The basic form of parameter expansion is $@{@var{parameter}@}. +The value of @var{parameter} is substituted. +The @var{parameter} is a shell parameter as described above +(@pxref{Shell Parameters}) or an array reference (@pxref{Arrays}). +The braces are required when @var{parameter} +is a positional parameter with more than one digit, +or when @var{parameter} is followed by a character that is not to be +interpreted as part of its name. + +If the first character of @var{parameter} is an exclamation point (!), +it introduces a level of variable indirection. +Bash uses the value of the variable formed from the rest of +@var{parameter} 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 @var{parameter} itself. +This is known as @code{indirect expansion}. +The exceptions to this are the expansions of $@{!@var{prefix}*@} +and $@{!@var{name}[@@]@} +described below. +The exclamation point must immediately follow the left brace in order to +introduce indirection. + +In each of the cases below, @var{word} is subject to tilde expansion, +parameter expansion, command substitution, and arithmetic expansion. + +When not performing substring expansion, using the form described +below (e.g., @samp{:-}), Bash tests for a parameter that is unset or null. +Omitting the colon results in a test only for a parameter that is unset. +Put another way, if the colon is included, +the operator tests for both @var{parameter}'s existence and that its value +is not null; if the colon is omitted, the operator tests only for existence. + +@table @code + +@item $@{@var{parameter}:@minus{}@var{word}@} +If @var{parameter} is unset or null, the expansion of +@var{word} is substituted. Otherwise, the value of +@var{parameter} is substituted. + +@item $@{@var{parameter}:=@var{word}@} +If @var{parameter} +is unset or null, the expansion of @var{word} +is assigned to @var{parameter}. +The value of @var{parameter} is then substituted. +Positional parameters and special parameters may not be assigned to +in this way. + +@item $@{@var{parameter}:?@var{word}@} +If @var{parameter} +is null or unset, the expansion of @var{word} (or a message +to that effect if @var{word} +is not present) is written to the standard error and the shell, if it +is not interactive, exits. Otherwise, the value of @var{parameter} is +substituted. + +@item $@{@var{parameter}:+@var{word}@} +If @var{parameter} +is null or unset, nothing is substituted, otherwise the expansion of +@var{word} is substituted. + +@item $@{@var{parameter}:@var{offset}@} +@itemx $@{@var{parameter}:@var{offset}:@var{length}@} +This is referred to as Substring Expansion. +It expands to up to @var{length} characters of the value of @var{parameter} +starting at the character specified by @var{offset}. +If @var{parameter} is @samp{@@}, an indexed array subscripted by +@samp{@@} or @samp{*}, or an associative array name, the results differ as +described below. +If @var{length} is omitted, it expands to the substring of the value of +@var{parameter} starting at the character specified by @var{offset} +and extending to the end of the value. +@var{length} and @var{offset} are arithmetic expressions +(@pxref{Shell Arithmetic}). + +If @var{offset} evaluates to a number less than zero, the value +is used as an offset in characters +from the end of the value of @var{parameter}. +If @var{length} evaluates to a number less than zero, +it is interpreted as an offset in characters +from the end of the value of @var{parameter} rather than +a number of characters, and the expansion is the characters between +@var{offset} and that result. +Note that a negative offset must be separated from the colon by at least +one space to avoid being confused with the @samp{:-} expansion. + +Here are some examples illustrating substring expansion on parameters and +subscripted arrays: + +@verbatim +$ string=01234567890abcdefgh +$ echo ${string:7} +7890abcdefgh +$ echo ${string:7:0} + +$ echo ${string:7:2} +78 +$ echo ${string:7:-2} +7890abcdef +$ echo ${string: -7} +bcdefgh +$ echo ${string: -7:0} + +$ echo ${string: -7:2} +bc +$ echo ${string: -7:-2} +bcdef +$ set -- 01234567890abcdefgh +$ echo ${1:7} +7890abcdefgh +$ echo ${1:7:0} + +$ echo ${1:7:2} +78 +$ echo ${1:7:-2} +7890abcdef +$ echo ${1: -7} +bcdefgh +$ echo ${1: -7:0} + +$ echo ${1: -7:2} +bc +$ echo ${1: -7:-2} +bcdef +$ array[0]=01234567890abcdefgh +$ echo ${array[0]:7} +7890abcdefgh +$ echo ${array[0]:7:0} + +$ echo ${array[0]:7:2} +78 +$ echo ${array[0]:7:-2} +7890abcdef +$ echo ${array[0]: -7} +bcdefgh +$ echo ${array[0]: -7:0} + +$ echo ${array[0]: -7:2} +bc +$ echo ${array[0]: -7:-2} +bcdef +@end verbatim + +If @var{parameter} is @samp{@@}, the result is @var{length} positional +parameters beginning at @var{offset}. +A negative @var{offset} is taken relative to one greater than the greatest +positional parameter, so an offset of -1 evaluates to the last positional +parameter. +It is an expansion error if @var{length} evaluates to a number less than zero. + +The following examples illustrate substring expansion using positional +parameters: + +@verbatim +$ set -- 1 2 3 4 5 6 7 8 9 0 a b c d e f g h +$ echo ${@:7} +7 8 9 0 a b c d e f g h +$ echo ${@:7:0} + +$ echo ${@:7:2} +7 8 +$ echo ${@:7:-2} +bash: -2: substring expression < 0 +$ echo ${@: -7:2} +b c +$ echo ${@:0} +./bash 1 2 3 4 5 6 7 8 9 0 a b c d e f g h +$ echo ${@:0:2} +./bash 1 +$ echo ${@: -7:0} + +@end verbatim + +If @var{parameter} is an indexed array name subscripted +by @samp{@@} or @samp{*}, the result is the @var{length} +members of the array beginning with @code{$@{@var{parameter}[@var{offset}]@}}. +A negative @var{offset} is taken relative to one greater than the maximum +index of the specified array. +It is an expansion error if @var{length} evaluates to a number less than zero. + +These examples show how you can use substring expansion with indexed +arrays: + +@verbatim +$ array=(0 1 2 3 4 5 6 7 8 9 0 a b c d e f g h) +$ echo ${array[@]:7} +7 8 9 0 a b c d e f g h +$ echo ${array[@]:7:2} +7 8 +$ echo ${array[@]: -7:2} +b c +$ echo ${array[@]: -7:-2} +bash: -2: substring expression < 0 +$ echo ${array[@]:0} +0 1 2 3 4 5 6 7 8 9 0 a b c d e f g h +$ echo ${array[@]:0:2} +0 1 +$ echo ${array[@]: -7:0} + +@end verbatim + +Substring expansion applied to an associative array produces undefined +results. + +Substring indexing is zero-based unless the positional parameters +are used, in which case the indexing starts at 1 by default. +If @var{offset} is 0, and the positional parameters are used, @code{$@@} is +prefixed to the list. + +@item $@{!@var{prefix}*@} +@itemx $@{!@var{prefix}@@@} +Expands to the names of variables whose names begin with @var{prefix}, +separated by the first character of the @env{IFS} special variable. +When @samp{@@} is used and the expansion appears within double quotes, each +variable name expands to a separate word. + +@item $@{!@var{name}[@@]@} +@itemx $@{!@var{name}[*]@} +If @var{name} is an array variable, expands to the list of array indices +(keys) assigned in @var{name}. +If @var{name} is not an array, expands to 0 if @var{name} is set and null +otherwise. +When @samp{@@} is used and the expansion appears within double quotes, each +key expands to a separate word. + +@item $@{#@var{parameter}@} +The length in characters of the expanded value of @var{parameter} is +substituted. +If @var{parameter} is @samp{*} or @samp{@@}, the value substituted +is the number of positional parameters. +If @var{parameter} is an array name subscripted by @samp{*} or @samp{@@}, +the value substituted is the number of elements in the array. +If @var{parameter} +is an indexed array name subscripted by a negative number, that number is +interpreted as relative to one greater than the maximum index of +@var{parameter}, so negative indices count back from the end of the +array, and an index of -1 references the last element. + +@item $@{@var{parameter}#@var{word}@} +@itemx $@{@var{parameter}##@var{word}@} +The @var{word} +is expanded to produce a pattern just as in filename +expansion (@pxref{Filename Expansion}). If the pattern matches +the beginning of the expanded value of @var{parameter}, +then the result of the expansion is the expanded value of @var{parameter} +with the shortest matching pattern (the @samp{#} case) or the +longest matching pattern (the @samp{##} case) deleted. +If @var{parameter} is @samp{@@} or @samp{*}, +the pattern removal operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If @var{parameter} is an array variable subscripted with +@samp{@@} or @samp{*}, +the pattern removal operation is applied to each member of the +array in turn, and the expansion is the resultant list. + +@item $@{@var{parameter}%@var{word}@} +@itemx $@{@var{parameter}%%@var{word}@} +The @var{word} is expanded to produce a pattern just as in +filename expansion. +If the pattern matches a trailing portion of the expanded value of +@var{parameter}, then the result of the expansion is the value of +@var{parameter} with the shortest matching pattern (the @samp{%} case) +or the longest matching pattern (the @samp{%%} case) deleted. +If @var{parameter} is @samp{@@} or @samp{*}, +the pattern removal operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If @var{parameter} +is an array variable subscripted with @samp{@@} or @samp{*}, +the pattern removal operation is applied to each member of the +array in turn, and the expansion is the resultant list. + +@item $@{@var{parameter}/@var{pattern}/@var{string}@} + +The @var{pattern} is expanded to produce a pattern just as in +filename expansion. +@var{Parameter} is expanded and the longest match of @var{pattern} +against its value is replaced with @var{string}. +If @var{pattern} begins with @samp{/}, all matches of @var{pattern} are +replaced with @var{string}. Normally only the first match is replaced. +If @var{pattern} begins with @samp{#}, it must match at the beginning +of the expanded value of @var{parameter}. +If @var{pattern} begins with @samp{%}, it must match at the end +of the expanded value of @var{parameter}. +If @var{string} is null, matches of @var{pattern} are deleted +and the @code{/} following @var{pattern} may be omitted. +If @var{parameter} is @samp{@@} or @samp{*}, +the substitution operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If @var{parameter} +is an array variable subscripted with @samp{@@} or @samp{*}, +the substitution operation is applied to each member of the +array in turn, and the expansion is the resultant list. + +@item $@{@var{parameter}^@var{pattern}@} +@itemx $@{@var{parameter}^^@var{pattern}@} +@itemx $@{@var{parameter},@var{pattern}@} +@itemx $@{@var{parameter},,@var{pattern}@} +This expansion modifies the case of alphabetic characters in @var{parameter}. +The @var{pattern} is expanded to produce a pattern just as in +filename expansion. +Each character in the expanded value of @var{parameter} is tested against +@var{pattern}, and, if it matches the pattern, its case is converted. +The pattern should not attempt to match more than one character. +The @samp{^} operator converts lowercase letters matching @var{pattern} +to uppercase; the @samp{,} operator converts matching uppercase letters +to lowercase. +The @samp{^^} and @samp{,,} expansions convert each matched character in the +expanded value; the @samp{^} and @samp{,} expansions match and convert only +the first character in the expanded value. +If @var{pattern} is omitted, it is treated like a @samp{?}, which matches +every character. +If @var{parameter} is @samp{@@} or @samp{*}, +the case modification operation is applied to each positional +parameter in turn, and the expansion is the resultant list. +If @var{parameter} +is an array variable subscripted with @samp{@@} or @samp{*}, +the case modification operation is applied to each member of the +array in turn, and the expansion is the resultant list. +@end table + +@node Command Substitution +@subsection Command Substitution +@cindex command substitution + +Command substitution allows the output of a command to replace +the command itself. +Command substitution occurs when a command is enclosed as follows: +@example +$(@var{command}) +@end example +@noindent +or +@example +`@var{command}` +@end example + +@noindent +Bash performs the expansion by executing @var{command} and +replacing the command substitution with the standard output of the +command, with any trailing newlines deleted. +Embedded newlines are not deleted, but they may be removed during +word splitting. +The command substitution @code{$(cat @var{file})} can be +replaced by the equivalent but faster @code{$(< @var{file})}. + +When the old-style backquote form of substitution is used, +backslash retains its literal meaning except when followed by +@samp{$}, @samp{`}, or @samp{\}. +The first backquote not preceded by a backslash terminates the +command substitution. +When using the @code{$(@var{command})} 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 +filename expansion are not performed on the results. + +@node Arithmetic Expansion +@subsection Arithmetic Expansion +@cindex expansion, arithmetic +@cindex arithmetic expansion + +Arithmetic expansion allows the evaluation of an arithmetic expression +and the substitution of the result. The format for arithmetic expansion is: + +@example +$(( @var{expression} )) +@end example + +The expression 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, +command 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 +(@pxref{Shell Arithmetic}). +If the expression is invalid, Bash prints a message indicating +failure to the standard error and no substitution occurs. + +@node Process Substitution +@subsection Process Substitution +@cindex process substitution + +Process substitution is supported on systems that support named +pipes (@sc{fifo}s) or the @file{/dev/fd} method of naming open files. +It takes the form of +@example +<(@var{list}) +@end example +@noindent +or +@example +>(@var{list}) +@end example +@noindent +The process @var{list} is run with its input or output connected to a +@sc{fifo} or some file in @file{/dev/fd}. The name of this file is +passed as an argument to the current command as the result of the +expansion. If the @code{>(@var{list})} form is used, writing to +the file will provide input for @var{list}. If the +@code{<(@var{list})} form is used, the file passed as an +argument should be read to obtain the output of @var{list}. +Note that no space may appear between the @code{<} or @code{>} +and the left parenthesis, otherwise the construct would be interpreted +as a redirection. + +When available, process substitution is performed simultaneously with +parameter and variable expansion, command substitution, and arithmetic +expansion. + +@node Word Splitting +@subsection Word Splitting +@cindex word splitting + +The shell scans the results of parameter expansion, command substitution, +and arithmetic expansion that did not occur within double quotes for +word splitting. + +The shell treats each character of @env{$IFS} as a delimiter, and splits +the results of the other expansions into words using these characters +as field terminators. +If @env{IFS} is unset, or its value is exactly @code{}, +the default, then sequences of +@code{ }, @code{}, and @code{} +at the beginning and end of the results of the previous +expansions are ignored, and any sequence of @env{IFS} +characters not at the beginning or end serves to delimit words. +If @env{IFS} has a value other than the default, then sequences of +the whitespace characters @code{space} and @code{tab} +are ignored at the beginning and end of the +word, as long as the whitespace character is in the +value of @env{IFS} (an @env{IFS} whitespace character). +Any character in @env{IFS} that is not @env{IFS} +whitespace, along with any adjacent @env{IFS} +whitespace characters, delimits a field. A sequence of @env{IFS} +whitespace characters is also treated as a delimiter. +If the value of @env{IFS} is null, no word splitting occurs. + +Explicit null arguments (@code{""} or @code{''}) are retained. +Unquoted implicit null arguments, resulting from the expansion of +parameters that have no values, are removed. +If a parameter with no value is expanded within double quotes, a +null argument results and is retained. + +Note that if no expansion occurs, no splitting +is performed. + +@node Filename Expansion +@subsection Filename Expansion +@menu +* Pattern Matching:: How the shell matches patterns. +@end menu +@cindex expansion, filename +@cindex expansion, pathname +@cindex filename expansion +@cindex pathname expansion + +After word splitting, unless the @option{-f} option has been set +(@pxref{The Set Builtin}), Bash scans each word for the characters +@samp{*}, @samp{?}, and @samp{[}. +If one of these characters appears, then the word is +regarded as a @var{pattern}, +and replaced with an alphabetically sorted list of +filenames matching the pattern (@pxref{Pattern Matching}). +If no matching filenames are found, +and the shell option @code{nullglob} is disabled, the word is left +unchanged. +If the @code{nullglob} option is set, and no matches are found, the word +is removed. +If the @code{failglob} shell option is set, and no matches are found, +an error message is printed and the command is not executed. +If the shell option @code{nocaseglob} is enabled, the match is performed +without regard to the case of alphabetic characters. + +When a pattern is used for filename expansion, the character @samp{.} +at the start of a filename or immediately following a slash +must be matched explicitly, unless the shell option @code{dotglob} is set. +When matching a filename, the slash character must always be +matched explicitly. +In other cases, the @samp{.} character is not treated specially. + +See the description of @code{shopt} in @ref{The Shopt Builtin}, +for a description of the @code{nocaseglob}, @code{nullglob}, +@code{failglob}, and @code{dotglob} options. + +The @env{GLOBIGNORE} +shell variable may be used to restrict the set of filenames matching a +pattern. If @env{GLOBIGNORE} +is set, each matching filename that also matches one of the patterns in +@env{GLOBIGNORE} is removed from the list of matches. The filenames +@file{.} and @file{..} +are always ignored when @env{GLOBIGNORE} +is set and not null. +However, setting @env{GLOBIGNORE} to a non-null value has the effect of +enabling the @code{dotglob} +shell option, so all other filenames beginning with a +@samp{.} will match. +To get the old behavior of ignoring filenames beginning with a +@samp{.}, make @samp{.*} one of the patterns in @env{GLOBIGNORE}. +The @code{dotglob} option is disabled when @env{GLOBIGNORE} +is unset. + +@node Pattern Matching +@subsubsection Pattern Matching +@cindex pattern matching +@cindex matching, pattern + +Any character that appears in a pattern, other than the special pattern +characters described below, matches itself. +The @sc{nul} character may not occur in a pattern. +A backslash escapes the following character; the +escaping backslash is discarded when matching. +The special pattern characters must be quoted if they are to be matched +literally. + +The special pattern characters have the following meanings: +@table @code +@item * +Matches any string, including the null string. +When the @code{globstar} shell option is enabled, and @samp{*} is used in +a filename expansion context, two adjacent @samp{*}s used as a single +pattern will match all files and zero or more directories and +subdirectories. +If followed by a @samp{/}, two adjacent @samp{*}s will match only +directories and subdirectories. +@item ? +Matches any single character. +@item [@dots{}] +Matches any one of the enclosed characters. A pair of characters +separated by a hyphen denotes a @var{range expression}; +any character that falls between those two characters, inclusive, +using the current locale's collating sequence and character set, +is matched. If the first character following the +@samp{[} is a @samp{!} or a @samp{^} +then any character not enclosed is matched. A @samp{@minus{}} +may be matched by including it as the first or last character +in the set. A @samp{]} may be matched by including it as the first +character in the set. +The sorting order of characters in range expressions is determined by +the current locale and the values of the +@env{LC_COLLATE} and @env{LC_ALL} shell variables, if set. + +For example, in the default C locale, @samp{[a-dx-z]} is equivalent to +@samp{[abcdxyz]}. Many locales sort characters in dictionary order, and in +these locales @samp{[a-dx-z]} is typically not equivalent to @samp{[abcdxyz]}; +it might be equivalent to @samp{[aBbCcDdxXyYz]}, for example. To obtain +the traditional interpretation of ranges in bracket expressions, you can +force the use of the C locale by setting the @env{LC_COLLATE} or +@env{LC_ALL} environment variable to the value @samp{C}, or enable the +@code{globasciiranges} shell option. + +Within @samp{[} and @samp{]}, @var{character classes} can be specified +using the syntax +@code{[:}@var{class}@code{:]}, where @var{class} is one of the +following classes defined in the @sc{posix} standard: +@example +alnum alpha ascii blank cntrl digit graph lower +print punct space upper word xdigit +@end example +@noindent +A character class matches any character belonging to that class. +The @code{word} character class matches letters, digits, and the character +@samp{_}. + +Within @samp{[} and @samp{]}, an @var{equivalence class} can be +specified using the syntax @code{[=}@var{c}@code{=]}, which +matches all characters with the same collation weight (as defined +by the current locale) as the character @var{c}. + +Within @samp{[} and @samp{]}, the syntax @code{[.}@var{symbol}@code{.]} +matches the collating symbol @var{symbol}. +@end table + +If the @code{extglob} shell option is enabled using the @code{shopt} +builtin, several extended pattern matching operators are recognized. +In the following description, a @var{pattern-list} is a list of one +or more patterns separated by a @samp{|}. +Composite patterns may be formed using one or more of the following +sub-patterns: + +@table @code +@item ?(@var{pattern-list}) +Matches zero or one occurrence of the given patterns. + +@item *(@var{pattern-list}) +Matches zero or more occurrences of the given patterns. + +@item +(@var{pattern-list}) +Matches one or more occurrences of the given patterns. + +@item @@(@var{pattern-list}) +Matches one of the given patterns. + +@item !(@var{pattern-list}) +Matches anything except one of the given patterns. +@end table + +@node Quote Removal +@subsection Quote Removal + +After the preceding expansions, all unquoted occurrences of the +characters @samp{\}, @samp{'}, and @samp{"} that did not +result from one of the above expansions are removed. + +@node Redirections +@section Redirections +@cindex redirection + +Before a command is executed, its input and output +may be @var{redirected} +using a special notation interpreted by the shell. +Redirection allows commands' file handles to be +duplicated, opened, closed, +made to refer to different files, +and can change the files the command reads from and writes to. +Redirection may also be used to modify file handles in the +current shell execution environment. The following redirection +operators may precede or appear anywhere within a +simple command or may follow a command. +Redirections are processed in the order they appear, from +left to right. + +Each redirection that may be preceded by a file descriptor number +may instead be preceded by a word of the form @{@var{varname}@}. +In this case, for each redirection operator except +>&- and <&-, the shell will allocate a file descriptor greater +than 10 and assign it to @{@var{varname}@}. If >&- or <&- is preceded +by @{@var{varname}@}, the value of @var{varname} defines the file +descriptor to close. + +In the following descriptions, if the file descriptor number is +omitted, and the first character of the redirection operator is +@samp{<}, the redirection refers to the standard input (file +descriptor 0). If the first character of the redirection operator +is @samp{>}, the redirection refers to the standard output (file +descriptor 1). + +The word following the redirection operator in the following +descriptions, unless otherwise noted, is subjected to brace expansion, +tilde expansion, parameter expansion, command substitution, arithmetic +expansion, quote removal, filename expansion, and word splitting. +If it expands to more than one word, Bash reports an error. + +Note that the order of redirections is significant. For example, +the command +@example +ls > @var{dirlist} 2>&1 +@end example +@noindent +directs both standard output (file descriptor 1) and standard error +(file descriptor 2) to the file @var{dirlist}, while the command +@example +ls 2>&1 > @var{dirlist} +@end example +@noindent +directs only the standard output to file @var{dirlist}, +because the standard error was made a copy of the standard output +before the standard output was redirected to @var{dirlist}. + +Bash handles several filenames specially when they are used in +redirections, as described in the following table: + +@table @code +@item /dev/fd/@var{fd} +If @var{fd} is a valid integer, file descriptor @var{fd} is duplicated. + +@item /dev/stdin +File descriptor 0 is duplicated. + +@item /dev/stdout +File descriptor 1 is duplicated. + +@item /dev/stderr +File descriptor 2 is duplicated. + +@item /dev/tcp/@var{host}/@var{port} +If @var{host} is a valid hostname or Internet address, and @var{port} +is an integer port number or service name, Bash attempts to open +the corresponding TCP socket. + +@item /dev/udp/@var{host}/@var{port} +If @var{host} is a valid hostname or Internet address, and @var{port} +is an integer port number or service name, Bash attempts to open +the corresponding UDP socket. +@end table + +A failure to open or create a file causes the redirection to fail. + +Redirections using file descriptors greater than 9 should be used with +care, as they may conflict with file descriptors the shell uses +internally. + +@subsection Redirecting Input +Redirection of input causes the file whose name results from +the expansion of @var{word} +to be opened for reading on file descriptor @code{n}, +or the standard input (file descriptor 0) if @code{n} +is not specified. + +The general format for redirecting input is: +@example +[@var{n}]<@var{word} +@end example + +@subsection Redirecting Output +Redirection of output causes the file whose name results from +the expansion of @var{word} +to be opened for writing on file descriptor @var{n}, +or the standard output (file descriptor 1) if @var{n} +is not specified. If the file does not exist it is created; +if it does exist it is truncated to zero size. + +The general format for redirecting output is: +@example +[@var{n}]>[|]@var{word} +@end example + +If the redirection operator is @samp{>}, and the @code{noclobber} +option to the @code{set} builtin has been enabled, the redirection +will fail if the file whose name results from the expansion of +@var{word} exists and is a regular file. +If the redirection operator is @samp{>|}, or the redirection operator is +@samp{>} and the @code{noclobber} option is not enabled, the redirection +is attempted even if the file named by @var{word} exists. + +@subsection Appending Redirected Output +Redirection of output in this fashion +causes the file whose name results from +the expansion of @var{word} +to be opened for appending on file descriptor @var{n}, +or the standard output (file descriptor 1) if @var{n} +is not specified. If the file does not exist it is created. + +The general format for appending output is: +@example +[@var{n}]>>@var{word} +@end example + +@subsection Redirecting Standard Output and Standard Error +This construct allows both the +standard output (file descriptor 1) and +the standard error output (file descriptor 2) +to be redirected to the file whose name is the +expansion of @var{word}. + +There are two formats for redirecting standard output and +standard error: +@example +&>@var{word} +@end example +@noindent +and +@example +>&@var{word} +@end example +@noindent +Of the two forms, the first is preferred. +This is semantically equivalent to +@example +>@var{word} 2>&1 +@end example +When using the second form, @var{word} may not expand to a number or +@samp{-}. If it does, other redirection operators apply +(see Duplicating File Descriptors below) for compatibility reasons. + +@subsection Appending Standard Output and Standard Error +This construct allows both the +standard output (file descriptor 1) and +the standard error output (file descriptor 2) +to be appended to the file whose name is the +expansion of @var{word}. + +The format for appending standard output and standard error is: +@example +&>>@var{word} +@end example +@noindent +This is semantically equivalent to +@example +>>@var{word} 2>&1 +@end example +(see Duplicating File Descriptors below). + +@subsection Here Documents +This type of redirection instructs the shell to read input from the +current source until a line containing only @var{word} +(with no trailing blanks) is seen. All of +the lines read up to that point are then used as the standard +input for a command. + +The format of here-documents is: +@example +<<[@minus{}]@var{word} + @var{here-document} +@var{delimiter} +@end example + +No parameter and variable expansion, command substitution, +arithmetic expansion, or filename expansion is performed on +@var{word}. If any characters in @var{word} are quoted, the +@var{delimiter} is the result of quote removal on @var{word}, +and the lines in the here-document are not expanded. +If @var{word} is unquoted, +all lines of the here-document are subjected to +parameter expansion, command substitution, and arithmetic expansion, +the character sequence @code{\newline} is ignored, and @samp{\} +must be used to quote the characters +@samp{\}, @samp{$}, and @samp{`}. + +If the redirection operator is @samp{<<-}, +then all leading tab characters are stripped from input lines and the +line containing @var{delimiter}. +This allows here-documents within shell scripts to be indented in a +natural fashion. + +@subsection Here Strings +A variant of here documents, the format is: +@example +<<< @var{word} +@end example + +The @var{word} undergoes +brace expansion, tilde expansion, parameter and variable expansion, +command substitution, arithmetic expansion, and quote removal. +Pathname expansion and word splitting are not performed. +The result is supplied as a single string to the command on its +standard input. + +@subsection Duplicating File Descriptors +The redirection operator +@example +[@var{n}]<&@var{word} +@end example +@noindent +is used to duplicate input file descriptors. +If @var{word} +expands to one or more digits, the file descriptor denoted by @var{n} +is made to be a copy of that file descriptor. +If the digits in @var{word} do not specify a file descriptor open for +input, a redirection error occurs. +If @var{word} +evaluates to @samp{-}, file descriptor @var{n} is closed. +If @var{n} is not specified, the standard input (file descriptor 0) is used. + +The operator +@example +[@var{n}]>&@var{word} +@end example +@noindent +is used similarly to duplicate output file descriptors. If +@var{n} is not specified, the standard output (file descriptor 1) is used. +If the digits in @var{word} do not specify a file descriptor open for +output, a redirection error occurs. +If @var{word} +evaluates to @samp{-}, file descriptor @var{n} is closed. +As a special case, if @var{n} is omitted, and @var{word} does not +expand to one or more digits or @samp{-}, the standard output and standard +error are redirected as described previously. + +@subsection Moving File Descriptors +The redirection operator +@example +[@var{n}]<&@var{digit}- +@end example +@noindent +moves the file descriptor @var{digit} to file descriptor @var{n}, +or the standard input (file descriptor 0) if @var{n} is not specified. +@var{digit} is closed after being duplicated to @var{n}. + +Similarly, the redirection operator +@example +[@var{n}]>&@var{digit}- +@end example +@noindent +moves the file descriptor @var{digit} to file descriptor @var{n}, +or the standard output (file descriptor 1) if @var{n} is not specified. + +@subsection Opening File Descriptors for Reading and Writing +The redirection operator +@example +[@var{n}]<>@var{word} +@end example +@noindent +causes the file whose name is the expansion of @var{word} +to be opened for both reading and writing on file descriptor +@var{n}, or on file descriptor 0 if @var{n} +is not specified. If the file does not exist, it is created. + +@node Executing Commands +@section Executing Commands + +@menu +* Simple Command Expansion:: How Bash expands simple commands before + executing them. +* Command Search and Execution:: How Bash finds commands and runs them. +* Command Execution Environment:: The environment in which Bash + executes commands that are not + shell builtins. +* Environment:: The environment given to a command. +* Exit Status:: The status returned by commands and how Bash + interprets it. +* Signals:: What happens when Bash or a command it runs + receives a signal. +@end menu + +@node Simple Command Expansion +@subsection Simple Command Expansion +@cindex command expansion + +When a simple command is executed, the shell performs the following +expansions, assignments, and redirections, from left to right. + +@enumerate +@item +The words that the parser has marked as variable assignments (those +preceding the command name) and redirections are saved for later +processing. + +@item +The words that are not variable assignments or redirections are +expanded (@pxref{Shell Expansions}). +If any words remain after expansion, the first word +is taken to be the name of the command and the remaining words are +the arguments. + +@item +Redirections are performed as described above (@pxref{Redirections}). + +@item +The text after the @samp{=} in each variable assignment undergoes tilde +expansion, parameter expansion, command substitution, arithmetic expansion, +and quote removal before being assigned to the variable. +@end enumerate + +If no command name results, the variable assignments affect the current +shell environment. Otherwise, the variables are added to the environment +of the executed command and do not affect the current shell environment. +If any of the assignments attempts to assign a value to a readonly variable, +an error occurs, and the command exits with a non-zero status. + +If no command name results, redirections are performed, but do not +affect the current shell environment. A redirection error causes the +command to exit with a non-zero status. + +If there is a command name left after expansion, execution proceeds as +described below. Otherwise, the command exits. If one of the expansions +contained a command substitution, the exit status of the command is +the exit status of the last command substitution performed. If there +were no command substitutions, the command exits with a status of zero. + +@node Command Search and Execution +@subsection Command Search and Execution +@cindex command execution +@cindex command search + +After a command has been split into words, if it results in a +simple command and an optional list of arguments, the following +actions are taken. + +@enumerate +@item +If the command name contains no slashes, the shell attempts to +locate it. If there exists a shell function by that name, that +function is invoked as described in @ref{Shell Functions}. + +@item +If the name does not match a function, the shell searches for +it in the list of shell builtins. If a match is found, that +builtin is invoked. + +@item +If the name is neither a shell function nor a builtin, +and contains no slashes, Bash searches each element of +@env{$PATH} for a directory containing an executable file +by that name. Bash uses a hash table to remember the full +pathnames of executable files to avoid multiple @env{PATH} searches +(see the description of @code{hash} in @ref{Bourne Shell Builtins}). +A full search of the directories in @env{$PATH} +is performed only if the command is not found in the hash table. +If the search is unsuccessful, the shell searches for a defined shell +function named @code{command_not_found_handle}. +If that function exists, it is invoked with the original command and +the original command's arguments as its arguments, and the function's +exit status becomes the exit status of the shell. +If that function is not defined, the shell prints an error +message and returns an exit status of 127. + +@item +If the search is successful, or if the command name contains +one or more slashes, the shell executes the named program in +a separate execution environment. +Argument 0 is set to the name given, and the remaining arguments +to the command are set to the arguments supplied, if any. + +@item +If this execution fails because the file is not in executable +format, and the file is not a directory, it is assumed to be a +@var{shell script} and the shell executes it as described in +@ref{Shell Scripts}. + +@item +If the command was not begun asynchronously, the shell waits for +the command to complete and collects its exit status. + +@end enumerate + +@node Command Execution Environment +@subsection Command Execution Environment +@cindex execution environment + +The shell has an @var{execution environment}, which consists of the +following: + +@itemize @bullet +@item +open files inherited by the shell at invocation, as modified by +redirections supplied to the @code{exec} builtin + +@item +the current working directory as set by @code{cd}, @code{pushd}, or +@code{popd}, or inherited by the shell at invocation + +@item +the file creation mode mask as set by @code{umask} or inherited from +the shell's parent + +@item +current traps set by @code{trap} + +@item +shell parameters that are set by variable assignment or with @code{set} +or inherited from the shell's parent in the environment + +@item +shell functions defined during execution or inherited from the shell's +parent in the environment + +@item +options enabled at invocation (either by default or with command-line +arguments) or by @code{set} + +@item +options enabled by @code{shopt} (@pxref{The Shopt Builtin}) + +@item +shell aliases defined with @code{alias} (@pxref{Aliases}) + +@item +various process @sc{id}s, including those of background jobs +(@pxref{Lists}), the value of @code{$$}, and the value of +@env{$PPID} + +@end itemize + +When a simple command other than a builtin or shell function +is to be executed, it +is invoked in a separate execution environment that consists of +the following. Unless otherwise noted, the values are inherited +from the shell. + +@itemize @bullet +@item +the shell's open files, plus any modifications and additions specified +by redirections to the command + +@item +the current working directory + +@item +the file creation mode mask + +@item +shell variables and functions marked for export, along with variables +exported for the command, passed in the environment (@pxref{Environment}) + +@item +traps caught by the shell are reset to the values inherited from the +shell's parent, and traps ignored by the shell are ignored + +@end itemize + +A command invoked in this separate environment cannot affect the +shell's execution environment. + +Command substitution, commands grouped with parentheses, +and asynchronous commands are invoked in a +subshell environment that is a duplicate of the shell environment, +except that traps caught by the shell are reset to the values +that the shell inherited from its parent at invocation. Builtin +commands that are invoked as part of a pipeline are also executed +in a subshell environment. Changes made to the subshell environment +cannot affect the shell's execution environment. + +Subshells spawned to execute command substitutions inherit the value of +the @option{-e} option from the parent shell. When not in @sc{posix} mode, +Bash clears the @option{-e} option in such subshells. + +If a command is followed by a @samp{&} and job control is not active, the +default standard input for the command is the empty file @file{/dev/null}. +Otherwise, the invoked command inherits the file descriptors of the calling +shell as modified by redirections. + +@node Environment +@subsection Environment +@cindex environment + +When a program is invoked it is given an array of strings +called the @var{environment}. +This is a list of name-value pairs, of the form @code{name=value}. + +Bash provides several ways to manipulate the environment. +On invocation, the shell scans its own environment and +creates a parameter for each name found, automatically marking +it for @var{export} +to child processes. Executed commands inherit the environment. +The @code{export} and @samp{declare -x} +commands allow parameters and functions to be added to and +deleted from the environment. If the value of a parameter +in the environment is modified, the new value becomes part +of the environment, replacing the old. The environment +inherited by any executed command consists of the shell's +initial environment, whose values may be modified in the shell, +less any pairs removed by the @code{unset} and @samp{export -n} +commands, plus any additions via the @code{export} and +@samp{declare -x} commands. + +The environment for any simple command +or function may be augmented temporarily by prefixing it with +parameter assignments, as described in @ref{Shell Parameters}. +These assignment statements affect only the environment seen +by that command. + +If the @option{-k} option is set (@pxref{The Set Builtin}), then all +parameter assignments are placed in the environment for a command, +not just those that precede the command name. + +When Bash invokes an external command, the variable @samp{$_} +is set to the full pathname of the command and passed to that +command in its environment. + +@node Exit Status +@subsection Exit Status +@cindex exit status + +The exit status of an executed command is the value returned by the +@var{waitpid} system call or equivalent function. Exit statuses +fall between 0 and 255, though, as explained below, the shell may +use values above 125 specially. Exit statuses from shell builtins and +compound commands are also limited to this range. Under certain +circumstances, the shell will use special values to indicate specific +failure modes. + +For the shell's purposes, a command which exits with a +zero exit status has succeeded. +A non-zero exit status indicates failure. +This seemingly counter-intuitive scheme is used so there +is one well-defined way to indicate success and a variety of +ways to indicate various failure modes. +When a command terminates on a fatal signal whose number is @var{N}, +Bash uses the value 128+@var{N} as the exit status. + +If a command is not found, the child process created to +execute it returns a status of 127. If a command is found +but is not executable, the return status is 126. + +If a command fails because of an error during expansion or redirection, +the exit status is greater than zero. + +The exit status is used by the Bash conditional commands +(@pxref{Conditional Constructs}) and some of the list +constructs (@pxref{Lists}). + +All of the Bash builtins return an exit status of zero if they succeed +and a non-zero status on failure, so they may be used by the +conditional and list constructs. +All builtins return an exit status of 2 to indicate incorrect usage, +generally invalid options or missing arguments. + +@node Signals +@subsection Signals +@cindex signal handling + +When Bash is interactive, in the absence of any traps, it ignores +@code{SIGTERM} (so that @samp{kill 0} does not kill an interactive shell), +and @code{SIGINT} +is caught and handled (so that the @code{wait} builtin is interruptible). +When Bash receives a @code{SIGINT}, it breaks out of any executing loops. +In all cases, Bash ignores @code{SIGQUIT}. +If job control is in effect (@pxref{Job Control}), Bash +ignores @code{SIGTTIN}, @code{SIGTTOU}, and @code{SIGTSTP}. + +Non-builtin commands started by Bash have signal handlers set to the +values inherited by the shell from its parent. +When job control is not in effect, asynchronous commands +ignore @code{SIGINT} and @code{SIGQUIT} in addition to these inherited +handlers. +Commands run as a result of +command substitution ignore the keyboard-generated job control signals +@code{SIGTTIN}, @code{SIGTTOU}, and @code{SIGTSTP}. + +The shell exits by default upon receipt of a @code{SIGHUP}. +Before exiting, an interactive shell resends the @code{SIGHUP} to +all jobs, running or stopped. +Stopped jobs are sent @code{SIGCONT} to ensure that they receive +the @code{SIGHUP}. +To prevent the shell from sending the @code{SIGHUP} signal to a +particular job, it should be removed +from the jobs table with the @code{disown} +builtin (@pxref{Job Control Builtins}) or marked +to not receive @code{SIGHUP} using @code{disown -h}. + +If the @code{huponexit} shell option has been set with @code{shopt} +(@pxref{The Shopt Builtin}), Bash sends a @code{SIGHUP} to all jobs when +an interactive login shell exits. + +If Bash is waiting for a command to complete and receives a signal +for which a trap has been set, the trap will not be executed until +the command completes. +When Bash is waiting for an asynchronous +command via the @code{wait} builtin, the reception of a signal for +which a trap has been set will cause the @code{wait} builtin to return +immediately with an exit status greater than 128, immediately after +which the trap is executed. + +@node Shell Scripts +@section Shell Scripts +@cindex shell script + +A shell script is a text file containing shell commands. When such +a file is used as the first non-option argument when invoking Bash, +and neither the @option{-c} nor @option{-s} option is supplied +(@pxref{Invoking Bash}), +Bash reads and executes commands from the file, then exits. This +mode of operation creates a non-interactive shell. The shell first +searches for the file in the current directory, and looks in the +directories in @env{$PATH} if not found there. + +When Bash runs +a shell script, it sets the special parameter @code{0} to the name +of the file, rather than the name of the shell, and the positional +parameters are set to the remaining arguments, if any are given. +If no additional arguments are supplied, the positional parameters +are unset. + +A shell script may be made executable by using the @code{chmod} command +to turn on the execute bit. When Bash finds such a file while +searching the @env{$PATH} for a command, it spawns a subshell to +execute it. In other words, executing +@example +filename @var{arguments} +@end example +@noindent +is equivalent to executing +@example +bash filename @var{arguments} +@end example + +@noindent +if @code{filename} is an executable shell script. +This subshell reinitializes itself, so that the effect is as if a +new shell had been invoked to interpret the script, with the +exception that the locations of commands remembered by the parent +(see the description of @code{hash} in @ref{Bourne Shell Builtins}) +are retained by the child. + +Most versions of Unix make this a part of the operating system's command +execution mechanism. If the first line of a script begins with +the two characters @samp{#!}, the remainder of the line specifies +an interpreter for the program. +Thus, you can specify Bash, @code{awk}, Perl, or some other +interpreter and write the rest of the script file in that language. + +The arguments to the interpreter +consist of a single optional argument following the interpreter +name on the first line of the script file, followed by the name of +the script file, followed by the rest of the arguments. Bash +will perform this action on operating systems that do not handle it +themselves. Note that some older versions of Unix limit the interpreter +name and argument to a maximum of 32 characters. + +Bash scripts often begin with @code{#! /bin/bash} (assuming that +Bash has been installed in @file{/bin}), since this ensures that +Bash will be used to interpret the script, even if it is executed +under another shell. + +@node Shell Builtin Commands +@chapter Shell Builtin Commands + +@menu +* Bourne Shell Builtins:: Builtin commands inherited from the Bourne + Shell. +* Bash Builtins:: Table of builtins specific to Bash. +* Modifying Shell Behavior:: Builtins to modify shell attributes and + optional behavior. +* Special Builtins:: Builtin commands classified specially by + POSIX. +@end menu + +Builtin commands are contained within the shell itself. +When the name of a builtin command is used as the first word of +a simple command (@pxref{Simple Commands}), the shell executes +the command directly, without invoking another program. +Builtin commands are necessary to implement functionality impossible +or inconvenient to obtain with separate utilities. + +This section briefly describes the builtins which Bash inherits from +the Bourne Shell, as well as the builtin commands which are unique +to or have been extended in Bash. + +Several builtin commands are described in other chapters: builtin +commands which provide the Bash interface to the job control +facilities (@pxref{Job Control Builtins}), the directory stack +(@pxref{Directory Stack Builtins}), the command history +(@pxref{Bash History Builtins}), and the programmable completion +facilities (@pxref{Programmable Completion Builtins}). + +Many of the builtins have been extended by @sc{posix} or Bash. + +Unless otherwise noted, each builtin command documented as accepting +options preceded by @samp{-} accepts @samp{--} +to signify the end of the options. +The @code{:}, @code{true}, @code{false}, and @code{test} +builtins do not accept options and do not treat @samp{--} specially. +The @code{exit}, @code{logout}, @code{break}, @code{continue}, @code{let}, +and @code{shift} builtins accept and process arguments beginning +with @samp{-} without requiring @samp{--}. +Other builtins that accept arguments but are not specified as accepting +options interpret arguments beginning with @samp{-} as invalid options and +require @samp{--} to prevent this interpretation. + +@node Bourne Shell Builtins +@section Bourne Shell Builtins + +The following shell builtin commands are inherited from the Bourne Shell. +These commands are implemented as specified by the @sc{posix} standard. + +@table @code +@item : @r{(a colon)} +@btindex : +@example +: [@var{arguments}] +@end example + +Do nothing beyond expanding @var{arguments} and performing redirections. +The return status is zero. + +@item . @r{(a period)} +@btindex . +@example +. @var{filename} [@var{arguments}] +@end example + +Read and execute commands from the @var{filename} argument in the +current shell context. If @var{filename} does not contain a slash, +the @env{PATH} variable is used to find @var{filename}. +When Bash is not in @sc{posix} mode, the current directory is searched +if @var{filename} is not found in @env{$PATH}. +If any @var{arguments} are supplied, they become the positional +parameters when @var{filename} is executed. Otherwise the positional +parameters are unchanged. +The return status is the exit status of the last command executed, or +zero if no commands are executed. If @var{filename} is not found, or +cannot be read, the return status is non-zero. +This builtin is equivalent to @code{source}. + +@item break +@btindex break +@example +break [@var{n}] +@end example + +Exit from a @code{for}, @code{while}, @code{until}, or @code{select} loop. +If @var{n} is supplied, the @var{n}th enclosing loop is exited. +@var{n} must be greater than or equal to 1. +The return status is zero unless @var{n} is not greater than or equal to 1. + +@item cd +@btindex cd +@example +cd [-L|[-P [-e]] [-@@] [@var{directory}] +@end example + +Change the current working directory to @var{directory}. +If @var{directory} is not supplied, the value of the @env{HOME} +shell variable is used. +Any additional arguments following @var{directory} are ignored. +If the shell variable +@env{CDPATH} exists, it is used as a search path: +each directory name in @env{CDPATH} is searched for +@var{directory}, with alternative directory names in @env{CDPATH} +separated by a colon (@samp{:}). +If @var{directory} begins with a slash, @env{CDPATH} is not used. + +The @option{-P} option means to not follow symbolic links: symbolic links +are resolved while @code{cd} is traversing @var{directory} and before +processing an instance of @samp{..} in @var{directory}. + +By default, or when the @option{-L} option is supplied, symbolic links +in @var{directory} are resolved after @code{cd} processes an instance +of @samp{..} in @var{directory}. + +If @samp{..} appears in @var{directory}, it is processed by removing the +immediately preceding pathname component, back to a slash or the beginning +of @var{directory}. + +If the @option{-e} option is supplied with @option{-P} +and the current working directory cannot be successfully determined +after a successful directory change, @code{cd} will return an unsuccessful +status. + +On systems that support it, the @option{-@@} option presents the extended +attributes associated with a file as a directory. + +If @var{directory} is @samp{-}, it is converted to @env{$OLDPWD} +before the directory change is attempted. + +If a non-empty directory name from @env{CDPATH} is used, or if +@samp{-} is the first argument, and the directory change is +successful, the absolute pathname of the new working directory is +written to the standard output. + +The return status is zero if the directory is successfully changed, +non-zero otherwise. + +@item continue +@btindex continue +@example +continue [@var{n}] +@end example + +Resume the next iteration of an enclosing @code{for}, @code{while}, +@code{until}, or @code{select} loop. +If @var{n} is supplied, the execution of the @var{n}th enclosing loop +is resumed. +@var{n} must be greater than or equal to 1. +The return status is zero unless @var{n} is not greater than or equal to 1. + +@item eval +@btindex eval +@example +eval [@var{arguments}] +@end example + +The arguments are concatenated together into a single command, which is +then read and executed, and its exit status returned as the exit status +of @code{eval}. +If there are no arguments or only empty arguments, the return status is +zero. + +@item exec +@btindex exec +@example +exec [-cl] [-a @var{name}] [@var{command} [@var{arguments}]] +@end example + +If @var{command} +is supplied, it replaces the shell without creating a new process. +If the @option{-l} option is supplied, the shell places a dash at the +beginning of the zeroth argument passed to @var{command}. +This is what the @code{login} program does. +The @option{-c} option causes @var{command} to be executed with an empty +environment. +If @option{-a} is supplied, the shell passes @var{name} as the zeroth +argument to @var{command}. +If @var{command} +cannot be executed for some reason, a non-interactive shell exits, +unless the @code{execfail} shell option +is enabled. In that case, it returns failure. +An interactive shell returns failure if the file cannot be executed. +If no @var{command} is specified, redirections may be used to affect +the current shell environment. If there are no redirection errors, the +return status is zero; otherwise the return status is non-zero. + +@item exit +@btindex exit +@example +exit [@var{n}] +@end example + +Exit the shell, returning a status of @var{n} to the shell's parent. +If @var{n} is omitted, the exit status is that of the last command executed. +Any trap on @code{EXIT} is executed before the shell terminates. + +@item export +@btindex export +@example +export [-fn] [-p] [@var{name}[=@var{value}]] +@end example + +Mark each @var{name} to be passed to child processes +in the environment. If the @option{-f} option is supplied, the @var{name}s +refer to shell functions; otherwise the names refer to shell variables. +The @option{-n} option means to no longer mark each @var{name} for export. +If no @var{names} are supplied, or if the @option{-p} option is given, a +list of names of all exported variables is displayed. +The @option{-p} option displays output in a form that may be reused as input. +If a variable name is followed by =@var{value}, the value of +the variable is set to @var{value}. + +The return status is zero unless an invalid option is supplied, one of +the names is not a valid shell variable name, or @option{-f} is supplied +with a name that is not a shell function. + +@item getopts +@btindex getopts +@example +getopts @var{optstring} @var{name} [@var{args}] +@end example + +@code{getopts} is used by shell scripts to parse positional parameters. +@var{optstring} contains the option characters to be recognized; if a +character is followed by a colon, the option is expected to have an +argument, which should be separated from it by whitespace. +The colon (@samp{:}) and question mark (@samp{?}) may not be +used as option characters. +Each time it is invoked, @code{getopts} +places the next option in the shell variable @var{name}, initializing +@var{name} if it does not exist, +and the index of the next argument to be processed into the +variable @env{OPTIND}. +@env{OPTIND} is initialized to 1 each time the shell or a shell script +is invoked. +When an option requires an argument, +@code{getopts} places that argument into the variable @env{OPTARG}. +The shell does not reset @env{OPTIND} automatically; it must be manually +reset between multiple calls to @code{getopts} within the same shell +invocation if a new set of parameters is to be used. + +When the end of options is encountered, @code{getopts} exits with a +return value greater than zero. +@env{OPTIND} is set to the index of the first non-option argument, +and @var{name} is set to @samp{?}. + +@code{getopts} +normally parses the positional parameters, but if more arguments are +given in @var{args}, @code{getopts} parses those instead. + +@code{getopts} can report errors in two ways. If the first character of +@var{optstring} is a colon, @var{silent} +error reporting is used. In normal operation, diagnostic messages +are printed when invalid options or missing option arguments are +encountered. +If the variable @env{OPTERR} +is set to 0, no error messages will be displayed, even if the first +character of @code{optstring} is not a colon. + +If an invalid option is seen, +@code{getopts} places @samp{?} into @var{name} and, if not silent, +prints an error message and unsets @env{OPTARG}. +If @code{getopts} is silent, the option character found is placed in +@env{OPTARG} and no diagnostic message is printed. + +If a required argument is not found, and @code{getopts} +is not silent, a question mark (@samp{?}) is placed in @var{name}, +@code{OPTARG} is unset, and a diagnostic message is printed. +If @code{getopts} is silent, then a colon (@samp{:}) is placed in +@var{name} and @env{OPTARG} is set to the option character found. + +@item hash +@btindex hash +@example +hash [-r] [-p @var{filename}] [-dt] [@var{name}] +@end example + +Each time @code{hash} is invoked, it remembers the full pathnames of the +commands specified as @var{name} arguments, +so they need not be searched for on subsequent invocations. +The commands are found by searching through the directories listed in +@env{$PATH}. +Any previously-remembered pathname is discarded. +The @option{-p} option inhibits the path search, and @var{filename} is +used as the location of @var{name}. +The @option{-r} option causes the shell to forget all remembered locations. +The @option{-d} option causes the shell to forget the remembered location +of each @var{name}. +If the @option{-t} option is supplied, the full pathname to which each +@var{name} corresponds is printed. If multiple @var{name} arguments are +supplied with @option{-t} the @var{name} is printed before the hashed +full pathname. +The @option{-l} option causes output to be displayed in a format +that may be reused as input. +If no arguments are given, or if only @option{-l} is supplied, +information about remembered commands is printed. +The return status is zero unless a @var{name} is not found or an invalid +option is supplied. + +@item pwd +@btindex pwd +@example +pwd [-LP] +@end example + +Print the absolute pathname of the current working directory. +If the @option{-P} option is supplied, the pathname printed will not +contain symbolic links. +If the @option{-L} option is supplied, the pathname printed may contain +symbolic links. +The return status is zero unless an error is encountered while +determining the name of the current directory or an invalid option +is supplied. + +@item readonly +@btindex readonly +@example +readonly [-aAf] [-p] [@var{name}[=@var{value}]] @dots{} +@end example + +Mark each @var{name} as readonly. +The values of these names may not be changed by subsequent assignment. +If the @option{-f} option is supplied, each @var{name} refers to a shell +function. +The @option{-a} option means each @var{name} refers to an indexed +array variable; the @option{-A} option means each @var{name} refers +to an associative array variable. +If both options are supplied, @option{-A} takes precedence. +If no @var{name} arguments are given, or if the @option{-p} +option is supplied, a list of all readonly names is printed. +The other options may be used to restrict the output to a subset of +the set of readonly names. +The @option{-p} option causes output to be displayed in a format that +may be reused as input. +If a variable name is followed by =@var{value}, the value of +the variable is set to @var{value}. +The return status is zero unless an invalid option is supplied, one of +the @var{name} arguments is not a valid shell variable or function name, +or the @option{-f} option is supplied with a name that is not a shell function. + +@item return +@btindex return +@example +return [@var{n}] +@end example + +Cause a shell function to stop executing and return the value @var{n} +to its caller. +If @var{n} is not supplied, the return value is the exit status of the +last command executed in the function. +If @code{return} is executed by a trap handler, the last command used to +determine the status is the last command executed before the trap handler. +if @code{return} is executed during a @code{DEBUG} trap, the last command +used to determine the status is the last command executed by the trap +handler before @code{return} was invoked. +@code{return} may also be used to terminate execution of a script +being executed with the @code{.} (@code{source}) builtin, +returning either @var{n} or +the exit status of the last command executed within the script as the exit +status of the script. +If @var{n} is supplied, the return value is its least significant +8 bits. +Any command associated with the @code{RETURN} trap is executed +before execution resumes after the function or script. +The return status is non-zero if @code{return} is supplied a non-numeric +argument or is used outside a function +and not during the execution of a script by @code{.} or @code{source}. + +@item shift +@btindex shift +@example +shift [@var{n}] +@end example + +Shift the positional parameters to the left by @var{n}. +The positional parameters from @var{n}+1 @dots{} @code{$#} are +renamed to @code{$1} @dots{} @code{$#}-@var{n}. +Parameters represented by the numbers @code{$#} to @code{$#}-@var{n}+1 +are unset. +@var{n} must be a non-negative number less than or equal to @code{$#}. +If @var{n} is zero or greater than @code{$#}, the positional parameters +are not changed. +If @var{n} is not supplied, it is assumed to be 1. +The return status is zero unless @var{n} is greater than @code{$#} or +less than zero, non-zero otherwise. + +@item test +@itemx [ +@btindex test +@btindex [ +@example +test @var{expr} +@end example + +Evaluate a conditional express +ion @var{expr} and return a status of 0 +(true) or 1 (false). +Each operator and operand must be a separate argument. +Expressions are composed of the primaries described below in +@ref{Bash Conditional Expressions}. +@code{test} does not accept any options, nor does it accept and ignore +an argument of @option{--} as signifying the end of options. + +When the @code{[} form is used, the last argument to the command must +be a @code{]}. + +Expressions may be combined using the following operators, listed in +decreasing order of precedence. +The evaluation depends on the number of arguments; see below. +Operator precedence is used when there are five or more arguments. + +@table @code +@item ! @var{expr} +True if @var{expr} is false. + +@item ( @var{expr} ) +Returns the value of @var{expr}. +This may be used to override the normal precedence of operators. + +@item @var{expr1} -a @var{expr2} +True if both @var{expr1} and @var{expr2} are true. + +@item @var{expr1} -o @var{expr2} +True if either @var{expr1} or @var{expr2} is true. +@end table + +The @code{test} and @code{[} builtins evaluate conditional +expressions using a set of rules based on the number of arguments. + +@table @asis +@item 0 arguments +The expression is false. + +@item 1 argument +The expression is true if and only if the argument is not null. + +@item 2 arguments +If the first argument is @samp{!}, the expression is true if and +only if the second argument is null. +If the first argument is one of the unary conditional operators +(@pxref{Bash Conditional Expressions}), the expression +is true if the unary test is true. +If the first argument is not a valid unary operator, the expression is +false. + +@item 3 arguments +The following conditions are applied in the order listed. +If the second argument is one of the binary conditional +operators (@pxref{Bash Conditional Expressions}), the +result of the expression is the result of the binary test using the +first and third arguments as operands. +The @samp{-a} and @samp{-o} operators are considered binary operators +when there are three arguments. +If the first argument is @samp{!}, the value is the negation of +the two-argument test using the second and third arguments. +If the first argument is exactly @samp{(} and the third argument is +exactly @samp{)}, the result is the one-argument test of the second +argument. +Otherwise, the expression is false. + +@item 4 arguments +If the first argument is @samp{!}, the result is the negation of +the three-argument expression composed of the remaining arguments. +Otherwise, the expression is parsed and evaluated according to +precedence using the rules listed above. + +@item 5 or more arguments +The expression is parsed and evaluated according to precedence +using the rules listed above. +@end table + +When used with @code{test} or @samp{[}, the @samp{<} and @samp{>} +operators sort lexicographically using ASCII ordering. + +@item times +@btindex times +@example +times +@end example + +Print out the user and system times used by the shell and its children. +The return status is zero. + +@item trap +@btindex trap +@example +trap [-lp] [@var{arg}] [@var{sigspec} @dots{}] +@end example + +The commands in @var{arg} are to be read and executed when the +shell receives signal @var{sigspec}. If @var{arg} is absent (and +there is a single @var{sigspec}) or +equal to @samp{-}, each specified signal's disposition is reset +to the value it had when the shell was started. +If @var{arg} is the null string, then the signal specified by +each @var{sigspec} is ignored by the shell and commands it invokes. +If @var{arg} is not present and @option{-p} has been supplied, +the shell displays the trap commands associated with each @var{sigspec}. +If no arguments are supplied, or +only @option{-p} is given, @code{trap} prints the list of commands +associated with each signal number in a form that may be reused as +shell input. +The @option{-l} option causes the shell to print a list of signal names +and their corresponding numbers. +Each @var{sigspec} is either a signal name or a signal number. +Signal names are case insensitive and the @code{SIG} prefix is optional. + +If a @var{sigspec} +is @code{0} or @code{EXIT}, @var{arg} is executed when the shell exits. +If a @var{sigspec} is @code{DEBUG}, the command @var{arg} is executed +before every simple command, @code{for} command, @code{case} command, +@code{select} command, every arithmetic @code{for} command, and before +the first command executes in a shell function. +Refer to the description of the @code{extdebug} option to the +@code{shopt} builtin (@pxref{The Shopt Builtin}) for details of its +effect on the @code{DEBUG} trap. +If a @var{sigspec} is @code{RETURN}, the command @var{arg} is executed +each time a shell function or a script executed with the @code{.} or +@code{source} builtins finishes executing. + +If a @var{sigspec} is @code{ERR}, the command @var{arg} +is executed whenever +a pipeline (which may consist of a single simple +command), a list, or a compound command returns a +non-zero exit status, +subject to the following conditions. +The @code{ERR} trap is not executed if the failed command is part of the +command list immediately following an @code{until} or @code{while} keyword, +part of the test following the @code{if} or @code{elif} reserved words, +part of a command executed in a @code{&&} or @code{||} list +except the command following the final @code{&&} or @code{||}, +any command in a pipeline but the last, +or if the command's return +status is being inverted using @code{!}. +These are the same conditions obeyed by the @code{errexit} (@option{-e}) +option. + +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 zero unless a @var{sigspec} does not specify a +valid signal. + +@item umask +@btindex umask +@example +umask [-p] [-S] [@var{mode}] +@end example + +Set the shell process's file creation mask to @var{mode}. If +@var{mode} begins with a digit, it is interpreted as an octal number; +if not, it is interpreted as a symbolic mode mask similar +to that accepted by the @code{chmod} command. If @var{mode} is +omitted, the current value of the mask is printed. If the @option{-S} +option is supplied without a @var{mode} argument, the mask is printed +in a symbolic format. +If the @option{-p} option is supplied, and @var{mode} +is omitted, the output is in a form that may be reused as input. +The return status is zero if the mode is successfully changed or if +no @var{mode} argument is supplied, and non-zero otherwise. + +Note that when the mode is interpreted as an octal number, each number +of the umask is subtracted from @code{7}. Thus, a umask of @code{022} +results in permissions of @code{755}. + +@item unset +@btindex unset +@example +unset [-fnv] [@var{name}] +@end example + +Remove each variable or function @var{name}. +If the @option{-v} option is given, each +@var{name} refers to a shell variable and that variable is remvoved. +If the @option{-f} option is given, the @var{name}s refer to shell +functions, and the function definition is removed. +If the @option{-n} option is supplied, and @var{name} is a variable with +the @var{nameref} attribute, @var{name} will be unset rather than the +variable it references. +@option{-n} has no effect if the @option{-f} option is supplied. +If no options are supplied, each @var{name} refers to a variable; if +there is no variable by that name, any function with that name is +unset. +Readonly variables and functions may not be unset. +The return status is zero unless a @var{name} is readonly. +@end table + +@node Bash Builtins +@section Bash Builtin Commands + +This section describes builtin commands which are unique to +or have been extended in Bash. +Some of these commands are specified in the @sc{posix} standard. + +@table @code + +@item alias +@btindex alias +@example +alias [-p] [@var{name}[=@var{value}] @dots{}] +@end example + +Without arguments or with the @option{-p} option, @code{alias} prints +the list of aliases on the standard output in a form that allows +them to be reused as input. +If arguments are supplied, an alias is defined for each @var{name} +whose @var{value} is given. If no @var{value} is given, the name +and value of the alias is printed. +Aliases are described in @ref{Aliases}. + +@item bind +@btindex bind +@example +bind [-m @var{keymap}] [-lpsvPSVX] +bind [-m @var{keymap}] [-q @var{function}] [-u @var{function}] [-r @var{keyseq}] +bind [-m @var{keymap}] -f @var{filename} +bind [-m @var{keymap}] -x @var{keyseq:shell-command} +bind [-m @var{keymap}] @var{keyseq:function-name} +bind [-m @var{keymap}] @var{keyseq:readline-command} +@end example + +Display current Readline (@pxref{Command Line Editing}) +key and function bindings, +bind a key sequence to a Readline function or macro, +or set a Readline variable. +Each non-option argument is a command as it would appear in a +Readline initialization file (@pxref{Readline Init File}), +but each binding or command must be passed as a separate argument; e.g., +@samp{"\C-x\C-r":re-read-init-file}. + +Options, if supplied, have the following meanings: + +@table @code +@item -m @var{keymap} +Use @var{keymap} as the keymap to be affected by +the subsequent bindings. Acceptable @var{keymap} +names are +@code{emacs}, +@code{emacs-standard}, +@code{emacs-meta}, +@code{emacs-ctlx}, +@code{vi}, +@code{vi-move}, +@code{vi-command}, and +@code{vi-insert}. +@code{vi} is equivalent to @code{vi-command}; +@code{emacs} is equivalent to @code{emacs-standard}. + +@item -l +List the names of all Readline functions. + +@item -p +Display Readline function names and bindings in such a way that they +can be used as input or in a Readline initialization file. + +@item -P +List current Readline function names and bindings. + +@item -v +Display Readline variable names and values in such a way that they +can be used as input or in a Readline initialization file. + +@item -V +List current Readline variable names and values. + +@item -s +Display Readline key sequences bound to macros and the strings they output +in such a way that they can be used as input or in a Readline +initialization file. + +@item -S +Display Readline key sequences bound to macros and the strings they output. + +@item -f @var{filename} +Read key bindings from @var{filename}. + +@item -q @var{function} +Query about which keys invoke the named @var{function}. + +@item -u @var{function} +Unbind all keys bound to the named @var{function}. + +@item -r @var{keyseq} +Remove any current binding for @var{keyseq}. + +@item -x @var{keyseq:shell-command} +Cause @var{shell-command} to be executed whenever @var{keyseq} is +entered. +When @var{shell-command} is executed, the shell sets the +@code{READLINE_LINE} variable to the contents of the Readline line +buffer and the @code{READLINE_POINT} variable to the current location +of the insertion point. +If the executed command changes the value of @code{READLINE_LINE} or +@code{READLINE_POINT}, those new values will be reflected in the +editing state. + +@item -X +List all key sequences bound to shell commands and the associated commands +in a format that can be reused as input. +@end table + +@noindent +The return status is zero unless an invalid option is supplied or an +error occurs. + +@item builtin +@btindex builtin +@example +builtin [@var{shell-builtin} [@var{args}]] +@end example + +Run a shell builtin, passing it @var{args}, and return its exit status. +This is useful when defining a shell function with the same +name as a shell builtin, retaining the functionality of the builtin within +the function. +The return status is non-zero if @var{shell-builtin} is not a shell +builtin command. + +@item caller +@btindex caller +@example +caller [@var{expr}] +@end example + +Returns the context of any active subroutine call (a shell function or +a script executed with the @code{.} or @code{source} builtins). + +Without @var{expr}, @code{caller} displays the line number and source +filename of the current subroutine call. +If a non-negative integer is supplied as @var{expr}, @code{caller} +displays the line number, subroutine name, and source file corresponding +to that position in the current execution call stack. This extra +information may be used, for example, to print a stack trace. The +current frame is frame 0. + +The return value is 0 unless the shell is not executing a subroutine +call or @var{expr} does not correspond to a valid position in the +call stack. + +@item command +@btindex command +@example +command [-pVv] @var{command} [@var{arguments} @dots{}] +@end example + +Runs @var{command} with @var{arguments} ignoring any shell function +named @var{command}. +Only shell builtin commands or commands found by searching the +@env{PATH} are executed. +If there is a shell function named @code{ls}, running @samp{command ls} +within the function will execute the external command @code{ls} +instead of calling the function recursively. +The @option{-p} option means to use a default value for @env{PATH} +that is guaranteed to find all of the standard utilities. +The return status in this case is 127 if @var{command} cannot be +found or an error occurred, and the exit status of @var{command} +otherwise. + +If either the @option{-V} or @option{-v} option is supplied, a +description of @var{command} is printed. The @option{-v} option +causes a single word indicating the command or file name used to +invoke @var{command} to be displayed; the @option{-V} option produces +a more verbose description. In this case, the return status is +zero if @var{command} is found, and non-zero if not. + +@item declare +@btindex declare +@example +declare [-aAfFgilnrtux] [-p] [@var{name}[=@var{value}] @dots{}] +@end example + +Declare variables and give them attributes. If no @var{name}s +are given, then display the values of variables instead. + +The @option{-p} option will display the attributes and values of each +@var{name}. +When @option{-p} is used with @var{name} arguments, additional options, +other than @option{-f} and @option{-F}, are ignored. + +When @option{-p} is supplied without @var{name} arguments, @code{declare} +will display the attributes and values of all variables having the +attributes specified by the additional options. +If no other options are supplied with @option{-p}, @code{declare} will +display the attributes and values of all shell variables. The @option{-f} +option will restrict the display to shell functions. + +The @option{-F} option inhibits the display of function definitions; +only the function name and attributes are printed. +If the @code{extdebug} shell option is enabled using @code{shopt} +(@pxref{The Shopt Builtin}), the source file name and line number where +the function is defined are displayed as well. +@option{-F} implies @option{-f}. + +The @option{-g} option forces variables to be created or modified at +the global scope, even when @code{declare} is executed in a shell function. +It is ignored in all other cases. + +The following options can be used to restrict output to variables with +the specified attributes or to give variables attributes: + +@table @code +@item -a +Each @var{name} is an indexed array variable (@pxref{Arrays}). + +@item -A +Each @var{name} is an associative array variable (@pxref{Arrays}). + +@item -f +Use function names only. + +@item -i +The variable is to be treated as +an integer; arithmetic evaluation (@pxref{Shell Arithmetic}) is +performed when the variable is assigned a value. + +@item -l +When the variable is assigned a value, all upper-case characters are +converted to lower-case. +The upper-case attribute is disabled. + +@item -n +Give each @var{name} the @var{nameref} attribute, making +it a name reference to another variable. +That other variable is defined by the value of @var{name}. +All references, assignments, and attribute modifications +to @var{name}, except for changing the +@option{-n} attribute itself, are performed on the variable referenced by +@var{name}'s value. +The nameref attribute cannot be applied to array variables. + +@item -r +Make @var{name}s readonly. These names cannot then be assigned values +by subsequent assignment statements or unset. + +@item -t +Give each @var{name} the @code{trace} attribute. +Traced functions inherit the @code{DEBUG} and @code{RETURN} traps from +the calling shell. +The trace attribute has no special meaning for variables. + +@item -u +When the variable is assigned a value, all lower-case characters are +converted to upper-case. +The lower-case attribute is disabled. + +@item -x +Mark each @var{name} for export to subsequent commands via +the environment. +@end table + +Using @samp{+} instead of @samp{-} turns off the attribute instead, +with the exceptions that @samp{+a} +may not be used to destroy an array variable and @samp{+r} will not +remove the readonly attribute. +When used in a function, @code{declare} makes each @var{name} local, +as with the @code{local} command, unless the @option{-g} option is used. +If a variable name is followed by =@var{value}, the value of the variable +is set to @var{value}. + +When using @option{-a} or @option{-A} and the compound assignment syntax to +create array variables, additional attributes do not take effect until +subsequent assignments. + +The return status is zero unless an invalid option is encountered, +an attempt is made to define a function using @samp{-f foo=bar}, +an attempt is made to assign a value to a readonly variable, +an attempt is made to assign a value to an array variable without +using the compound assignment syntax (@pxref{Arrays}), +one of the @var{names} is not a valid shell variable name, +an attempt is made to turn off readonly status for a readonly variable, +an attempt is made to turn off array status for an array variable, +or an attempt is made to display a non-existent function with @option{-f}. + +@item echo +@btindex echo +@example +echo [-neE] [@var{arg} @dots{}] +@end example + +Output the @var{arg}s, separated by spaces, terminated with a +newline. +The return status is 0 unless a write error occurs. +If @option{-n} is specified, the trailing newline is suppressed. +If the @option{-e} option is given, interpretation of the following +backslash-escaped characters is enabled. +The @option{-E} option disables the interpretation of these escape characters, +even on systems where they are interpreted by default. +The @code{xpg_echo} shell option may be used to +dynamically determine whether or not @code{echo} expands these +escape characters by default. +@code{echo} does not interpret @option{--} to mean the end of options. + +@code{echo} interprets the following escape sequences: +@table @code +@item \a +alert (bell) +@item \b +backspace +@item \c +suppress further output +@item \e +@itemx \E +escape +@item \f +form feed +@item \n +new line +@item \r +carriage return +@item \t +horizontal tab +@item \v +vertical tab +@item \\ +backslash +@item \0@var{nnn} +the eight-bit character whose value is the octal value @var{nnn} +(zero to three octal digits) +@item \x@var{HH} +the eight-bit character whose value is the hexadecimal value @var{HH} +(one or two hex digits) +@item \u@var{HHHH} +the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value +@var{HHHH} (one to four hex digits) +@item \U@var{HHHHHHHH} +the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value +@var{HHHHHHHH} (one to eight hex digits) +@end table + +@item enable +@btindex enable +@example +enable [-a] [-dnps] [-f @var{filename}] [@var{name} @dots{}] +@end example + +Enable and disable builtin shell commands. +Disabling a builtin allows a disk command which has the same name +as a shell builtin to be executed without specifying a full pathname, +even though the shell normally searches for builtins before disk commands. +If @option{-n} is used, the @var{name}s become disabled. Otherwise +@var{name}s are enabled. For example, to use the @code{test} binary +found via @env{$PATH} instead of the shell builtin version, type +@samp{enable -n test}. + +If the @option{-p} option is supplied, or no @var{name} arguments appear, +a list of shell builtins is printed. With no other arguments, the list +consists of all enabled shell builtins. +The @option{-a} option means to list +each builtin with an indication of whether or not it is enabled. + +The @option{-f} option means to load the new builtin command @var{name} +from shared object @var{filename}, on systems that support dynamic loading. +The @option{-d} option will delete a builtin loaded with @option{-f}. + +If there are no options, a list of the shell builtins is displayed. +The @option{-s} option restricts @code{enable} to the @sc{posix} special +builtins. If @option{-s} is used with @option{-f}, the new builtin becomes +a special builtin (@pxref{Special Builtins}). + +The return status is zero unless a @var{name} is not a shell builtin +or there is an error loading a new builtin from a shared object. + +@item help +@btindex help +@example +help [-dms] [@var{pattern}] +@end example + +Display helpful information about builtin commands. +If @var{pattern} is specified, @code{help} gives detailed help +on all commands matching @var{pattern}, otherwise a list of +the builtins is printed. + +Options, if supplied, have the following meanings: + +@table @code +@item -d +Display a short description of each @var{pattern} +@item -m +Display the description of each @var{pattern} in a manpage-like format +@item -s +Display only a short usage synopsis for each @var{pattern} +@end table + +The return status is zero unless no command matches @var{pattern}. + +@item let +@btindex let +@example +let @var{expression} [@var{expression} @dots{}] +@end example + +The @code{let} builtin allows arithmetic to be performed on shell +variables. Each @var{expression} is evaluated according to the +rules given below in @ref{Shell Arithmetic}. If the +last @var{expression} evaluates to 0, @code{let} returns 1; +otherwise 0 is returned. + +@item local +@btindex local +@example +local [@var{option}] @var{name}[=@var{value}] @dots{} +@end example + +For each argument, a local variable named @var{name} is created, +and assigned @var{value}. +The @var{option} can be any of the options accepted by @code{declare}. +@code{local} can only be used within a function; it makes the variable +@var{name} have a visible scope restricted to that function and its +children. The return status is zero unless @code{local} is used outside +a function, an invalid @var{name} is supplied, or @var{name} is a +readonly variable. + +@item logout +@btindex logout +@example +logout [@var{n}] +@end example + +Exit a login shell, returning a status of @var{n} to the shell's +parent. + +@item mapfile +@btindex mapfile +@example +mapfile [-d @var{delim}] [-n @var{count}] [-O @var{origin}] [-s @var{count}] [-t] [-u @var{fd}] + [-C @var{callback}] [-c @var{quantum}] [@var{array}] +@end example + +Read lines from the standard input into the indexed array variable @var{array}, +or from file descriptor @var{fd} +if the @option{-u} option is supplied. +The variable @code{MAPFILE} is the default @var{array}. +Options, if supplied, have the following meanings: + +@table @code + +@item -d +The first character of @var{delim} is used to terminate each input line, +rather than newline. +@item -n +Copy at most @var{count} lines. If @var{count} is 0, all lines are copied. +@item -O +Begin assigning to @var{array} at index @var{origin}. +The default index is 0. +@item -s +Discard the first @var{count} lines read. +@item -t +Remove a trailing newline from each line read. +@item -u +Read lines from file descriptor @var{fd} instead of the standard input. +@item -C +Evaluate @var{callback} each time @var{quantum}P lines are read. +The @option{-c} option specifies @var{quantum}. +@item -c +Specify the number of lines read between each call to @var{callback}. +@end table + +If @option{-C} is specified without @option{-c}, +the default quantum is 5000. +When @var{callback} is evaluated, it is supplied the index of the next +array element to be assigned and the line to be assigned to that element +as additional arguments. +@var{callback} is evaluated after the line is read but before the +array element is assigned. + +If not supplied with an explicit origin, @code{mapfile} will clear @var{array} +before assigning to it. + +@code{mapfile} returns successfully unless an invalid option or option +argument is supplied, @var{array} is invalid or unassignable, or @var{array} +is not an indexed array. + +@item printf +@btindex printf +@example +printf [-v @var{var}] @var{format} [@var{arguments}] +@end example + +Write the formatted @var{arguments} to the standard output under the +control of the @var{format}. +The @option{-v} option causes the output to be assigned to the variable +@var{var} rather than being printed to the standard output. + +The @var{format} is a character string which contains three types of objects: +plain characters, which are simply copied to standard output, character +escape sequences, which are converted and copied to the standard output, and +format specifications, each of which causes printing of the next successive +@var{argument}. +In addition to the standard @code{printf(1)} formats, @code{printf} +interprets the following extensions: + +@table @code +@item %b +Causes @code{printf} to expand backslash escape sequences in the +corresponding @var{argument}, +except that @samp{\c} terminates output, backslashes in +@samp{\'}, @samp{\"}, and @samp{\?} are not removed, and octal escapes +beginning with @samp{\0} may contain up to four digits. +@item %q +Causes @code{printf} to output the +corresponding @var{argument} in a format that can be reused as shell input. +@item %(@var{datefmt})T +Causes @code{printf} to output the date-time string resulting from using +@var{datefmt} as a format string for @code{strftime}(3). +The corresponding @var{argument} is an integer representing the number of +seconds since the epoch. +Two special argument values may be used: -1 represents the current +time, and -2 represents the time the shell was invoked. +If no argument is specified, conversion behaves as if -1 had been given. +This is an exception to the usual @code{printf} behavior. +@end table + +@noindent +Arguments to non-string format specifiers are treated as C language constants, +except that a leading plus or minus sign is allowed, and if the leading +character is a single or double quote, the value is the ASCII value of +the following character. + +The @var{format} is reused as necessary to consume all of the @var{arguments}. +If the @var{format} requires more @var{arguments} than are supplied, the +extra format specifications behave as if a zero value or null string, as +appropriate, had been supplied. The return value is zero on success, +non-zero on failure. + +@item read +@btindex read +@example +read [-ers] [-a @var{aname}] [-d @var{delim}] [-i @var{text}] [-n @var{nchars}] + [-N @var{nchars}] [-p @var{prompt}] [-t @var{timeout}] [-u @var{fd}] [@var{name} @dots{}] +@end example + +One line is read from the standard input, or from the file descriptor +@var{fd} supplied as an argument to the @option{-u} option, and the first word +is assigned to the first @var{name}, the second word to the second @var{name}, +and so on, with leftover words and their intervening separators assigned +to the last @var{name}. +If there are fewer words read from the input stream than names, +the remaining names are assigned empty values. +The characters in the value of the @env{IFS} variable +are used to split the line into words using the same rules the shell +uses for expansion (described above in @ref{Word Splitting}). +The backslash character @samp{\} may be used to remove any special +meaning for the next character read and for line continuation. +If no names are supplied, the line read is assigned to the +variable @env{REPLY}. +The return code is zero, unless end-of-file is encountered, @code{read} +times out (in which case the return code is greater than 128), +a variable assignment error (such as assigning to a readonly variable) occurs, +or an invalid file descriptor is supplied as the argument to @option{-u}. + +Options, if supplied, have the following meanings: + +@table @code +@item -a @var{aname} +The words are assigned to sequential indices of the array variable +@var{aname}, starting at 0. +All elements are removed from @var{aname} before the assignment. +Other @var{name} arguments are ignored. + +@item -d @var{delim} +The first character of @var{delim} is used to terminate the input line, +rather than newline. + +@item -e +Readline (@pxref{Command Line Editing}) is used to obtain the line. +Readline uses the current (or default, if line editing was not previously +active) editing settings. + +@item -i @var{text} +If Readline is being used to read the line, @var{text} is placed into +the editing buffer before editing begins. + +@item -n @var{nchars} +@code{read} returns after reading @var{nchars} characters rather than +waiting for a complete line of input, but honor a delimiter if fewer +than @var{nchars} characters are read before the delimiter. + +@item -N @var{nchars} +@code{read} returns after reading exactly @var{nchars} characters rather +than waiting for a complete line of input, unless EOF is encountered or +@code{read} times out. +Delimiter characters encountered in the input are +not treated specially and do not cause @code{read} to return until +@var{nchars} characters are read. + +@item -p @var{prompt} +Display @var{prompt}, without a trailing newline, before attempting +to read any input. +The prompt is displayed only if input is coming from a terminal. + +@item -r +If this option is given, backslash does not act as an escape character. +The backslash is considered to be part of the line. +In particular, a backslash-newline pair may not be used as a line +continuation. + +@item -s +Silent mode. If input is coming from a terminal, characters are +not echoed. + +@item -t @var{timeout} +Cause @code{read} to time out and return failure if a complete line of +input (or a specified number of characters) +is not read within @var{timeout} seconds. +@var{timeout} may be a decimal number with a fractional portion following +the decimal point. +This option is only effective if @code{read} is reading input from a +terminal, pipe, or other special file; it has no effect when reading +from regular files. +If @code{read} times out, @code{read} saves any partial input read into +the specified variable @var{name}. +If @var{timeout} is 0, @code{read} returns immediately, without trying to +read and data. The exit status is 0 if input is available on +the specified file descriptor, non-zero otherwise. +The exit status is greater than 128 if the timeout is exceeded. + +@item -u @var{fd} +Read input from file descriptor @var{fd}. +@end table + +@item readarray +@btindex readarray +@example +readarray [-d @var{delim}] [-n @var{count}] [-O @var{origin}] [-s @var{count}] [-t] [-u @var{fd}] + [-C @var{callback}] [-c @var{quantum}] [@var{array}] +@end example + +Read lines from the standard input into the indexed array variable @var{array}, +or from file descriptor @var{fd} +if the @option{-u} option is supplied. + +A synonym for @code{mapfile}. + +@item source +@btindex source +@example +source @var{filename} +@end example + +A synonym for @code{.} (@pxref{Bourne Shell Builtins}). + +@item type +@btindex type +@example +type [-afptP] [@var{name} @dots{}] +@end example + +For each @var{name}, indicate how it would be interpreted if used as a +command name. + +If the @option{-t} option is used, @code{type} prints a single word +which is one of @samp{alias}, @samp{function}, @samp{builtin}, +@samp{file} or @samp{keyword}, +if @var{name} is an alias, shell function, shell builtin, +disk file, or shell reserved word, respectively. +If the @var{name} is not found, then nothing is printed, and +@code{type} returns a failure status. + +If the @option{-p} option is used, @code{type} either returns the name +of the disk file that would be executed, or nothing if @option{-t} +would not return @samp{file}. + +The @option{-P} option forces a path search for each @var{name}, even if +@option{-t} would not return @samp{file}. + +If a command is hashed, @option{-p} and @option{-P} print the hashed value, +which is not necessarily the file that appears first in @code{$PATH}. + +If the @option{-a} option is used, @code{type} returns all of the places +that contain an executable named @var{file}. +This includes aliases and functions, if and only if the @option{-p} option +is not also used. + +If the @option{-f} option is used, @code{type} does not attempt to find +shell functions, as with the @code{command} builtin. + +The return status is zero if all of the @var{names} are found, non-zero +if any are not found. + +@item typeset +@btindex typeset +@example +typeset [-afFgrxilnrtux] [-p] [@var{name}[=@var{value}] @dots{}] +@end example + +The @code{typeset} command is supplied for compatibility with the Korn +shell. +It is a synonym for the @code{declare} builtin command. + +@item ulimit +@btindex ulimit +@example +ulimit [-abcdefilmnpqrstuvxHST] [@var{limit}] +@end example + +@code{ulimit} provides control over the resources available to processes +started by the shell, on systems that allow such control. If an +option is given, it is interpreted as follows: + +@table @code +@item -S +Change and report the soft limit associated with a resource. + +@item -H +Change and report the hard limit associated with a resource. + +@item -a +All current limits are reported. + +@item -b +The maximum socket buffer size. + +@item -c +The maximum size of core files created. + +@item -d +The maximum size of a process's data segment. + +@item -e +The maximum scheduling priority ("nice"). + +@item -f +The maximum size of files written by the shell and its children. + +@item -i +The maximum number of pending signals. + +@item -l +The maximum size that may be locked into memory. + +@item -m +The maximum resident set size (many systems do not honor this limit). + +@item -n +The maximum number of open file descriptors (most systems do not +allow this value to be set). + +@item -p +The pipe buffer size. + +@item -q +The maximum number of bytes in POSIX message queues. + +@item -r +The maximum real-time scheduling priority. + +@item -s +The maximum stack size. + +@item -t +The maximum amount of cpu time in seconds. + +@item -u +The maximum number of processes available to a single user. + +@item -v +The maximum amount of virtual memory available to the shell, and, on +some systems, to its children. + +@item -x +The maximum number of file locks. + +@item -T +The maximum number of threads. +@end table + +If @var{limit} is given, and the @option{-a} option is not used, +@var{limit} is the new value of the specified resource. +The special @var{limit} values @code{hard}, @code{soft}, and +@code{unlimited} stand for the current hard limit, the current soft limit, +and no limit, respectively. +A hard limit cannot be increased by a non-root user once it is set; +a soft limit may be increased up to the value of the hard limit. +Otherwise, the current value of the soft limit for the specified resource +is printed, unless the @option{-H} option is supplied. +When setting new limits, if neither @option{-H} nor @option{-S} is supplied, +both the hard and soft limits are set. +If no option is given, then @option{-f} is assumed. Values are in 1024-byte +increments, except for @option{-t}, which is in seconds; @option{-p}, +which is in units of 512-byte blocks; and @option{-T}, @option{-b}, +@option{-n} and @option{-u}, which are unscaled values. + +The return status is zero unless an invalid option or argument is supplied, +or an error occurs while setting a new limit. + +@item unalias +@btindex unalias +@example +unalias [-a] [@var{name} @dots{} ] +@end example + +Remove each @var{name} from the list of aliases. If @option{-a} is +supplied, all aliases are removed. +Aliases are described in @ref{Aliases}. +@end table + +@node Modifying Shell Behavior +@section Modifying Shell Behavior + +@menu +* The Set Builtin:: Change the values of shell attributes and + positional parameters. +* The Shopt Builtin:: Modify shell optional behavior. +@end menu + +@node The Set Builtin +@subsection The Set Builtin + +This builtin is so complicated that it deserves its own section. @code{set} +allows you to change the values of shell options and set the positional +parameters, or to display the names and values of shell variables. + +@table @code +@item set +@btindex set +@example +set [--abefhkmnptuvxBCEHPT] [-o @var{option-name}] [@var{argument} @dots{}] +set [+abefhkmnptuvxBCEHPT] [+o @var{option-name}] [@var{argument} @dots{}] +@end example + +If no options or arguments are supplied, @code{set} displays the names +and values of all shell variables and functions, sorted according to the +current locale, in a format that may be reused as input +for setting or resetting the currently-set variables. +Read-only variables cannot be reset. +In @sc{posix} mode, only shell variables are listed. + +When options are supplied, they set or unset shell attributes. +Options, if specified, have the following meanings: + +@table @code +@item -a +Mark variables and function which are modified or created for export +to the environment of subsequent commands. + +@item -b +Cause the status of terminated background jobs to be reported +immediately, rather than before printing the next primary prompt. + +@item -e +Exit immediately if +a pipeline (@pxref{Pipelines}), which may consist of a single simple command +(@pxref{Simple Commands}), +a list (@pxref{Lists}), +or a compound command (@pxref{Compound Commands}) +returns a non-zero status. +The shell does not exit if the command that fails is part of the +command list immediately following a @code{while} or @code{until} keyword, +part of the test in an @code{if} statement, +part of any command executed in a @code{&&} or @code{||} list except +the command following the final @code{&&} or @code{||}, +any command in a pipeline but the last, +or if the command's return status is being inverted with @code{!}. +If a compound command other than a subshell +returns a non-zero status because a command failed +while @option{-e} was being ignored, the shell does not exit. +A trap on @code{ERR}, if set, is executed before the shell exits. + +This option applies to the shell environment and each subshell environment +separately (@pxref{Command Execution Environment}), 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 +@option{-e} is being ignored, +none of the commands executed within the compound command or function body +will be affected by the @option{-e} setting, even if @option{-e} is set +and a command returns a failure status. +If a compound command or shell function sets @option{-e} while executing in +a context where @option{-e} is ignored, that setting will not have any +effect until the compound command or the command containing the function +call completes. + +@item -f +Disable filename expansion (globbing). + +@item -h +Locate and remember (hash) commands as they are looked up for execution. +This option is enabled by default. + +@item -k +All arguments in the form of assignment statements are placed +in the environment for a command, not just those that precede +the command name. + +@item -m +Job control is enabled (@pxref{Job Control}). +All processes run in a separate process group. +When a background job completes, the shell prints a line +containing its exit status. + +@item -n +Read commands but do not execute them; this may be used to check a +script for syntax errors. +This option is ignored by interactive shells. + +@item -o @var{option-name} + +Set the option corresponding to @var{option-name}: + +@table @code +@item allexport +Same as @code{-a}. + +@item braceexpand +Same as @code{-B}. + +@item emacs +Use an @code{emacs}-style line editing interface (@pxref{Command Line Editing}). +This also affects the editing interface used for @code{read -e}. + +@item errexit +Same as @code{-e}. + +@item errtrace +Same as @code{-E}. + +@item functrace +Same as @code{-T}. + +@item hashall +Same as @code{-h}. + +@item histexpand +Same as @code{-H}. + +@item history +Enable command history, as described in @ref{Bash History Facilities}. +This option is on by default in interactive shells. + +@item ignoreeof +An interactive shell will not exit upon reading EOF. + +@item keyword +Same as @code{-k}. + +@item monitor +Same as @code{-m}. + +@item noclobber +Same as @code{-C}. + +@item noexec +Same as @code{-n}. + +@item noglob +Same as @code{-f}. + +@item nolog +Currently ignored. + +@item notify +Same as @code{-b}. + +@item nounset +Same as @code{-u}. + +@item onecmd +Same as @code{-t}. + +@item physical +Same as @code{-P}. + +@item pipefail +If set, the return value of a pipeline is the value of the last +(rightmost) command to exit with a non-zero status, or zero if all +commands in the pipeline exit successfully. +This option is disabled by default. + +@item posix +Change the behavior of Bash where the default operation differs +from the @sc{posix} standard to match the standard +(@pxref{Bash POSIX Mode}). +This is intended to make Bash behave as a strict superset of that +standard. + +@item privileged +Same as @code{-p}. + +@item verbose +Same as @code{-v}. + +@item vi +Use a @code{vi}-style line editing interface. +This also affects the editing interface used for @code{read -e}. + +@item xtrace +Same as @code{-x}. +@end table + +@item -p +Turn on privileged mode. +In this mode, the @env{$BASH_ENV} and @env{$ENV} files are not +processed, shell functions are not inherited from the environment, +and the @env{SHELLOPTS}, @env{BASHOPTS}, @env{CDPATH} and @env{GLOBIGNORE} +variables, if they appear in the environment, are ignored. +If the shell is started with the effective user (group) id not equal to the +real user (group) id, and the @option{-p} option is not supplied, these actions +are taken and the effective user id is set to the real user id. +If the @option{-p} option is supplied at startup, the effective user id is +not reset. +Turning this option off causes the effective user +and group ids to be set to the real user and group ids. + +@item -t +Exit after reading and executing one command. + +@item -u +Treat unset variables and parameters other than the special parameters +@samp{@@} or @samp{*} as an error when performing parameter expansion. +An error message will be written to the standard error, and a non-interactive +shell will exit. + +@item -v +Print shell input lines as they are read. + +@item -x +Print a trace of simple commands, @code{for} commands, @code{case} +commands, @code{select} commands, and arithmetic @code{for} commands +and their arguments or associated word lists after they are +expanded and before they are executed. The value of the @env{PS4} +variable is expanded and the resultant value is printed before +the command and its expanded arguments. + +@item -B +The shell will perform brace expansion (@pxref{Brace Expansion}). +This option is on by default. + +@item -C +Prevent output redirection using @samp{>}, @samp{>&}, and @samp{<>} +from overwriting existing files. + +@item -E +If set, any trap on @code{ERR} is inherited by shell functions, command +substitutions, and commands executed in a subshell environment. +The @code{ERR} trap is normally not inherited in such cases. + +@item -H +Enable @samp{!} style history substitution (@pxref{History Interaction}). +This option is on by default for interactive shells. + +@item -P +If set, do not resolve symbolic links when performing commands such as +@code{cd} which change the current directory. The physical directory +is used instead. By default, Bash follows +the logical chain of directories when performing commands +which change the current directory. + +For example, if @file{/usr/sys} is a symbolic link to @file{/usr/local/sys} +then: +@example +$ cd /usr/sys; echo $PWD +/usr/sys +$ cd ..; pwd +/usr +@end example + +@noindent +If @code{set -P} is on, then: +@example +$ cd /usr/sys; echo $PWD +/usr/local/sys +$ cd ..; pwd +/usr/local +@end example + +@item -T +If set, any trap on @code{DEBUG} and @code{RETURN} are inherited by +shell functions, command substitutions, and commands executed +in a subshell environment. +The @code{DEBUG} and @code{RETURN} traps are normally not inherited +in such cases. + +@item -- +If no arguments follow this option, then the positional parameters are +unset. Otherwise, the positional parameters are set to the +@var{arguments}, even if some of them begin with a @samp{-}. + +@item - +Signal the end of options, cause all remaining @var{arguments} +to be assigned to the positional parameters. The @option{-x} +and @option{-v} options are turned off. +If there are no arguments, the positional parameters remain unchanged. +@end table + +Using @samp{+} rather than @samp{-} causes these options to be +turned off. The options can also be used upon invocation of the +shell. The current set of options may be found in @code{$-}. + +The remaining N @var{arguments} are positional parameters and are +assigned, in order, to @code{$1}, @code{$2}, @dots{} @code{$N}. +The special parameter @code{#} is set to N. + +The return status is always zero unless an invalid option is supplied. +@end table + +@node The Shopt Builtin +@subsection The Shopt Builtin + +This builtin allows you to change additional shell optional behavior. + +@table @code + +@item shopt +@btindex shopt +@example +shopt [-pqsu] [-o] [@var{optname} @dots{}] +@end example + +Toggle the values of settings controlling optional shell behavior. +The settings can be either those listed below, or, if the +@option{-o} option is used, those available with the @option{-o} +option to the @code{set} builtin command (@pxref{The Set Builtin}). +With no options, or with the @option{-p} option, a list of all settable +options is displayed, with an indication of whether or not each is set. +The @option{-p} option causes output to be displayed in a form that +may be reused as input. +Other options have the following meanings: + +@table @code +@item -s +Enable (set) each @var{optname}. + +@item -u +Disable (unset) each @var{optname}. + +@item -q +Suppresses normal output; the return status +indicates whether the @var{optname} is set or unset. +If multiple @var{optname} arguments are given with @option{-q}, +the return status is zero if all @var{optnames} are enabled; +non-zero otherwise. + +@item -o +Restricts the values of +@var{optname} to be those defined for the @option{-o} option to the +@code{set} builtin (@pxref{The Set Builtin}). +@end table + +If either @option{-s} or @option{-u} +is used with no @var{optname} arguments, @code{shopt} shows only +those options which are set or unset, respectively. + +Unless otherwise noted, the @code{shopt} options are disabled (off) +by default. + +The return status when listing options is zero if all @var{optnames} +are enabled, non-zero otherwise. When setting or unsetting options, +the return status is zero unless an @var{optname} is not a valid shell +option. + +The list of @code{shopt} options is: +@table @code + +@item autocd +If set, a command name that is the name of a directory is executed as if +it were the argument to the @code{cd} command. +This option is only used by interactive shells. + +@item cdable_vars +If this is set, an argument to the @code{cd} builtin command that +is not a directory is assumed to be the name of a variable whose +value is the directory to change to. + +@item cdspell +If set, minor errors in the spelling of a directory component in a +@code{cd} command will be corrected. +The errors checked for are transposed characters, +a missing character, and a character too many. +If a correction is found, the corrected path is printed, +and the command proceeds. +This option is only used by interactive shells. + +@item checkhash +If this is set, Bash checks that a command found in the hash +table exists before trying to execute it. If a hashed command no +longer exists, a normal path search is performed. + +@item checkjobs +If set, Bash lists the status of any stopped and running jobs before +exiting an interactive shell. If any jobs are running, this causes +the exit to be deferred until a second exit is attempted without an +intervening command (@pxref{Job Control}). +The shell always postpones exiting if any jobs are stopped. + +@item checkwinsize +If set, Bash checks the window size after each command + and, if necessary, updates the values of +@env{LINES} and @env{COLUMNS}. + +@item cmdhist +If set, Bash +attempts to save all lines of a multiple-line +command in the same history entry. This allows +easy re-editing of multi-line commands. + +@item compat31 +If set, Bash +changes its behavior to that of version 3.1 with respect to quoted +arguments to the conditional command's @samp{=~} operator +and with respect to locale-specific +string comparison when using the @code{[[} +conditional command's @samp{<} and @samp{>} operators. +Bash versions prior to bash-4.1 use ASCII collation and strcmp(3); +bash-4.1 and later use the current locale's collation sequence and strcoll(3). + +@item compat32 +If set, Bash +changes its behavior to that of version 3.2 with respect to locale-specific +string comparison when using the @code{[[} +conditional command's @samp{<} and @samp{>} operators (see previous item). + +@item compat40 +If set, Bash +changes its behavior to that of version 4.0 with respect to locale-specific +string comparison when using the @code{[[} +conditional command's @samp{<} and @samp{>} operators (see description +of @code{compat31}) +and the effect of interrupting a command list. +Bash versions 4.0 and later interrupt the list as if the shell received the +interrupt; previous versions continue with the next command in the list. + +@item compat41 +If set, Bash, when in @sc{posix} mode, treats a single quote in a double-quoted +parameter expansion as a special character. The single quotes must match +(an even number) and the characters between the single quotes are considered +quoted. This is the behavior of @sc{posix} mode through version 4.1. +The default Bash behavior remains as in previous versions. + +@item compat42 +If set, Bash +does not process the replacement string in the pattern substitution word +expansion using quote removal. + +@item complete_fullquote +If set, Bash +quotes all shell metacharacters in filenames and directory names when +performing completion. +If not set, Bash +removes metacharacters such as the dollar sign from the set of +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 backslashes to quote completed +filenames. +This variable is set by default, which is the default Bash behavior in +versions through 4.2. + +@item direxpand +If set, Bash +replaces directory names with the results of word expansion when performing +filename completion. This changes the contents of the readline editing +buffer. +If not set, Bash attempts to preserve what the user typed. + +@item dirspell +If set, Bash +attempts spelling correction on directory names during word completion +if the directory name initially supplied does not exist. + +@item dotglob +If set, Bash includes filenames beginning with a `.' in +the results of filename expansion. + +@item execfail +If this is set, a non-interactive shell will not exit if +it cannot execute the file specified as an argument to the @code{exec} +builtin command. An interactive shell does not exit if @code{exec} +fails. + +@item expand_aliases +If set, aliases are expanded as described below under Aliases, +@ref{Aliases}. +This option is enabled by default for interactive shells. + +@item extdebug +If set, behavior intended for use by debuggers is enabled: + +@enumerate +@item +The @option{-F} option to the @code{declare} builtin (@pxref{Bash Builtins}) +displays the source file name and line number corresponding to each function +name supplied as an argument. + +@item +If the command run by the @code{DEBUG} trap returns a non-zero value, the +next command is skipped and not executed. + +@item +If the command run by the @code{DEBUG} trap returns a value of 2, and the +shell is executing in a subroutine (a shell function or a shell script +executed by the @code{.} or @code{source} builtins), the shell simulates +a call to @code{return}. + +@item +@code{BASH_ARGC} and @code{BASH_ARGV} are updated as described in their +descriptions (@pxref{Bash Variables}). + +@item +Function tracing is enabled: command substitution, shell functions, and +subshells invoked with @code{( @var{command} )} inherit the +@code{DEBUG} and @code{RETURN} traps. + +@item +Error tracing is enabled: command substitution, shell functions, and +subshells invoked with @code{( @var{command} )} inherit the +@code{ERR} trap. +@end enumerate + +@item extglob +If set, the extended pattern matching features described above +(@pxref{Pattern Matching}) are enabled. + +@item extquote +If set, @code{$'@var{string}'} and @code{$"@var{string}"} quoting is +performed within @code{$@{@var{parameter}@}} expansions +enclosed in double quotes. This option is enabled by default. + +@item failglob +If set, patterns which fail to match filenames during filename expansion +result in an expansion error. + +@item force_fignore +If set, the suffixes specified by the @env{FIGNORE} shell variable +cause words to be ignored when performing word completion even if +the ignored words are the only possible completions. +@xref{Bash Variables}, for a description of @env{FIGNORE}. +This option is enabled by default. + +@item globasciiranges +If set, range expressions used in pattern matching bracket expressions +(@pxref{Pattern Matching}) +behave as if in the traditional C locale when performing +comparisons. That is, the current locale's collating sequence +is not taken into account, so +@samp{b} will not collate between @samp{A} and @samp{B}, +and upper-case and lower-case ASCII characters will collate together. + +@item globstar +If set, the pattern @samp{**} used in a filename expansion context will +match all files and zero or more directories and subdirectories. +If the pattern is followed by a @samp{/}, only directories and +subdirectories match. + +@item gnu_errfmt +If set, shell error messages are written in the standard @sc{gnu} error +message format. + +@item histappend +If set, the history list is appended to the file named by the value +of the @env{HISTFILE} +variable when the shell exits, rather than overwriting the file. + +@item histreedit +If set, and Readline +is being used, a user is given the opportunity to re-edit a +failed history substitution. + +@item histverify +If set, and Readline +is being used, the results of history substitution are not immediately +passed to the shell parser. Instead, the resulting line is loaded into +the Readline editing buffer, allowing further modification. + +@item hostcomplete +If set, and Readline is being used, Bash will attempt to perform +hostname completion when a word containing a @samp{@@} is being +completed (@pxref{Commands For Completion}). This option is enabled +by default. + +@item huponexit +If set, Bash will send @code{SIGHUP} to all jobs when an interactive +login shell exits (@pxref{Signals}). + +@item interactive_comments +Allow a word beginning with @samp{#} +to cause that word and all remaining characters on that +line to be ignored in an interactive shell. +This option is enabled by default. + +@item lastpipe +If set, and job control is not active, the shell runs the last command of +a pipeline not executed in the background in the current shell environment. + +@item lithist +If enabled, and the @code{cmdhist} +option is enabled, multi-line commands are saved to the history with +embedded newlines rather than using semicolon separators where possible. + +@item login_shell +The shell sets this option if it is started as a login shell +(@pxref{Invoking Bash}). +The value may not be changed. + +@item mailwarn +If set, and a file that Bash is checking for mail has been +accessed since the last time it was checked, the message +@code{"The mail in @var{mailfile} has been read"} is displayed. + +@item no_empty_cmd_completion +If set, and Readline is being used, Bash will not attempt to search +the @env{PATH} for possible completions when completion is attempted +on an empty line. + +@item nocaseglob +If set, Bash matches filenames in a case-insensitive fashion when +performing filename expansion. + +@item nocasematch +If set, Bash matches patterns in a case-insensitive fashion when +performing matching while executing @code{case} or @code{[[} +conditional commands. + +@item nullglob +If set, Bash allows filename patterns which match no +files to expand to a null string, rather than themselves. + +@item progcomp +If set, the programmable completion facilities +(@pxref{Programmable Completion}) are enabled. +This option is enabled by default. + +@item promptvars +If set, prompt strings undergo +parameter expansion, command substitution, arithmetic +expansion, and quote removal after being expanded +as described below (@pxref{Controlling the Prompt}). +This option is enabled by default. + +@item restricted_shell +The shell sets this option if it is started in restricted mode +(@pxref{The Restricted Shell}). +The value may not be changed. +This is not reset when the startup files are executed, allowing +the startup files to discover whether or not a shell is restricted. + +@item shift_verbose +If this is set, the @code{shift} +builtin prints an error message when the shift count exceeds the +number of positional parameters. + +@item sourcepath +If set, the @code{source} builtin uses the value of @env{PATH} +to find the directory containing the file supplied as an argument. +This option is enabled by default. + +@item xpg_echo +If set, the @code{echo} builtin expands backslash-escape sequences +by default. + +@end table + +@noindent +The return status when listing options is zero if all @var{optnames} +are enabled, non-zero otherwise. +When setting or unsetting options, the return status is zero unless an +@var{optname} is not a valid shell option. +@end table + +@node Special Builtins +@section Special Builtins +@cindex special builtin + +For historical reasons, the @sc{posix} standard has classified +several builtin commands as @emph{special}. +When Bash is executing in @sc{posix} mode, the special builtins +differ from other builtin commands in three respects: + +@enumerate +@item +Special builtins are found before shell functions during command lookup. + +@item +If a special builtin returns an error status, a non-interactive shell exits. + +@item +Assignment statements preceding the command stay in effect in the shell +environment after the command completes. +@end enumerate + +When Bash is not executing in @sc{posix} mode, these builtins behave no +differently than the rest of the Bash builtin commands. +The Bash @sc{posix} mode is described in @ref{Bash POSIX Mode}. + +These are the @sc{posix} special builtins: +@example +@w{break : . continue eval exec exit export readonly return set} +@w{shift trap unset} +@end example + +@node Shell Variables +@chapter Shell Variables + +@menu +* Bourne Shell Variables:: Variables which Bash uses in the same way + as the Bourne Shell. +* Bash Variables:: List of variables that exist in Bash. +@end menu + +This chapter describes the shell variables that Bash uses. +Bash automatically assigns default values to a number of variables. + +@node Bourne Shell Variables +@section Bourne Shell Variables + +Bash uses certain shell variables in the same way as the Bourne shell. +In some cases, Bash assigns a default value to the variable. + +@vtable @code + +@item CDPATH +A colon-separated list of directories used as a search path for +the @code{cd} builtin command. + +@item HOME +The current user's home directory; the default for the @code{cd} builtin +command. +The value of this variable is also used by tilde expansion +(@pxref{Tilde Expansion}). + +@item IFS +A list of characters that separate fields; used when the shell splits +words as part of expansion. + +@item MAIL +If this parameter is set to a filename or directory name +and the @env{MAILPATH} variable +is not set, Bash informs the user of the arrival of mail in +the specified file or Maildir-format directory. + +@item MAILPATH +A colon-separated list of filenames which the shell periodically checks +for new mail. +Each list entry can specify the message that is printed when new mail +arrives in the mail file by separating the filename from the message with +a @samp{?}. +When used in the text of the message, @code{$_} expands to the name of +the current mail file. + +@item OPTARG +The value of the last option argument processed by the @code{getopts} builtin. + +@item OPTIND +The index of the last option argument processed by the @code{getopts} builtin. + +@item PATH +A colon-separated list of directories in which the shell looks for +commands. +A zero-length (null) directory name in the value of @code{PATH} indicates the +current directory. +A null directory name may appear as two adjacent colons, or as an initial +or trailing colon. + + +@item PS1 +The primary prompt string. The default value is @samp{\s-\v\$ }. +@xref{Controlling the Prompt}, for the complete list of escape +sequences that are expanded before @env{PS1} is displayed. + +@item PS2 +The secondary prompt string. The default value is @samp{> }. + +@end vtable + +@node Bash Variables +@section Bash Variables + +These variables are set or used by Bash, but other shells +do not normally treat them specially. + +A few variables used by Bash are described in different chapters: +variables for controlling the job control facilities +(@pxref{Job Control Variables}). + +@vtable @code + +@item BASH +The full pathname used to execute the current instance of Bash. + +@item BASHOPTS +A colon-separated list of enabled shell options. Each word in +the list is a valid argument for the @option{-s} option to the +@code{shopt} builtin command (@pxref{The Shopt Builtin}). +The options appearing in @env{BASHOPTS} are those reported +as @samp{on} by @samp{shopt}. +If this variable is in the environment when Bash +starts up, each shell option in the list will be enabled before +reading any startup files. This variable is readonly. + +@item BASHPID +Expands to the process ID of the current Bash process. +This differs from @code{$$} under certain circumstances, such as subshells +that do not require Bash to be re-initialized. + +@item BASH_ALIASES +An associative array variable whose members correspond to the internal +list of aliases as maintained by the @code{alias} builtin. +(@pxref{Bourne Shell Builtins}). +Elements added to this array appear in the alias list; unsetting array +elements cause aliases to be removed from the alias list. + +@item BASH_ARGC +An array variable whose values are the number of parameters in each +frame of the current bash execution call stack. The number of +parameters to the current subroutine (shell function or script executed +with @code{.} or @code{source}) is at the top of the stack. When a +subroutine is executed, the number of parameters passed is pushed onto +@code{BASH_ARGC}. +The shell sets @code{BASH_ARGC} only when in extended debugging mode +(see @ref{The Shopt Builtin} +for a description of the @code{extdebug} option to the @code{shopt} +builtin). + +@item BASH_ARGV +An array variable containing all of the parameters in the current bash +execution call stack. The final parameter of the last subroutine call +is at the top of the stack; the first parameter of the initial call is +at the bottom. When a subroutine is executed, the parameters supplied +are pushed onto @code{BASH_ARGV}. +The shell sets @code{BASH_ARGV} only when in extended debugging mode +(see @ref{The Shopt Builtin} +for a description of the @code{extdebug} option to the @code{shopt} +builtin). + +@item BASH_CMDS +An associative array variable whose members correspond to the internal +hash table of commands as maintained by the @code{hash} builtin +(@pxref{Bourne Shell Builtins}). +Elements added to this array appear in the hash table; unsetting array +elements cause commands to be removed from the hash table. + +@item BASH_COMMAND +The command currently being executed or about to be executed, unless the +shell is executing a command as the result of a trap, +in which case it is the command executing at the time of the trap. + +@item BASH_COMPAT +The value is used to set the shell's compatibility level. +@xref{The Shopt Builtin}, for a description of the various compatibility +levels and their effects. +The value may be a decimal number (e.g., 4.2) or an integer (e.g., 42) +corresponding to the desired compatibility level. +If @code{BASH_COMPAT} is unset or set to the empty string, the compatibility +level is set to the default for the current version. +If @code{BASH_COMPAT} is set to a value that is not one of the valid +compatibility levels, the shell prints an error message and sets the +compatibility level to the default for the current version. +The valid compatibility levels correspond to the compatibility options +accepted by the @code{shopt} builtin described above (for example, +@var{compat42} means that 4.2 and 42 are valid values). +The current version is also a valid value. + +@item BASH_ENV +If this variable is set when Bash is invoked to execute a shell +script, its value is expanded and used as the name of a startup file +to read before executing the script. @xref{Bash Startup Files}. + +@item BASH_EXECUTION_STRING +The command argument to the @option{-c} invocation option. + +@item BASH_LINENO +An array variable whose members are the line numbers in source files +where each corresponding member of @var{FUNCNAME} was invoked. +@code{$@{BASH_LINENO[$i]@}} is the line number in the source file +(@code{$@{BASH_SOURCE[$i+1]@}}) where +@code{$@{FUNCNAME[$i]@}} was called (or @code{$@{BASH_LINENO[$i-1]@}} if +referenced within another shell function). +Use @code{LINENO} to obtain the current line number. + +@item BASH_REMATCH +An array variable whose members are assigned by the @samp{=~} binary +operator to the @code{[[} conditional command +(@pxref{Conditional Constructs}). +The element with index 0 is the portion of the string +matching the entire regular expression. +The element with index @var{n} is the portion of the +string matching the @var{n}th parenthesized subexpression. +This variable is read-only. + +@item BASH_SOURCE +An array variable whose members are the source filenames where the +corresponding shell function names in the @code{FUNCNAME} array +variable are defined. +The shell function @code{$@{FUNCNAME[$i]@}} is defined in the file +@code{$@{BASH_SOURCE[$i]@}} and called from @code{$@{BASH_SOURCE[$i+1]@}} + +@item BASH_SUBSHELL +Incremented by one within each subshell or subshell environment when +the shell begins executing in that environment. +The initial value is 0. + +@item BASH_VERSINFO +A readonly array variable (@pxref{Arrays}) +whose members hold version information for this instance of Bash. +The values assigned to the array members are as follows: + +@table @code + +@item BASH_VERSINFO[0] +The major version number (the @var{release}). + +@item BASH_VERSINFO[1] +The minor version number (the @var{version}). + +@item BASH_VERSINFO[2] +The patch level. + +@item BASH_VERSINFO[3] +The build version. + +@item BASH_VERSINFO[4] +The release status (e.g., @var{beta1}). + +@item BASH_VERSINFO[5] +The value of @env{MACHTYPE}. +@end table + +@item BASH_VERSION +The version number of the current instance of Bash. + +@item BASH_XTRACEFD +If set to an integer corresponding to a valid file descriptor, Bash +will write the trace output generated when @samp{set -x} +is enabled to that file descriptor. +This allows tracing output to be separated from diagnostic and error +messages. +The file descriptor is closed when @code{BASH_XTRACEFD} is unset or assigned +a new value. +Unsetting @code{BASH_XTRACEFD} or assigning it the empty string causes the +trace output to be sent to the standard error. +Note that setting @code{BASH_XTRACEFD} to 2 (the standard error file +descriptor) and then unsetting it will result in the standard error +being closed. + +@item CHILD_MAX +Set the number of exited child status values for the shell to remember. +Bash will not allow this value to be decreased below a @sc{posix}-mandated +minimum, and there is a maximum value (currently 8192) that this may +not exceed. +The minimum value is system-dependent. + +@item COLUMNS +Used by the @code{select} command to determine the terminal width +when printing selection lists. +Automatically set if the @code{checkwinsize} option is enabled +(@pxref{The Shopt Builtin}), or in an interactive shell upon receipt of a +@code{SIGWINCH}. + +@item COMP_CWORD +An index into @env{$@{COMP_WORDS@}} of the word containing the current +cursor position. +This variable is available only in shell functions invoked by the +programmable completion facilities (@pxref{Programmable Completion}). + +@item COMP_LINE +The current command line. +This variable is available only in shell functions and external +commands invoked by the +programmable completion facilities (@pxref{Programmable Completion}). + +@item COMP_POINT +The index of the current cursor position relative to the beginning of +the current command. +If the current cursor position is at the end of the current command, +the value of this variable is equal to @code{$@{#COMP_LINE@}}. +This variable is available only in shell functions and external +commands invoked by the +programmable completion facilities (@pxref{Programmable Completion}). + +@item COMP_TYPE +Set to an integer value corresponding to the type of completion attempted +that caused a completion function to be called: +@var{TAB}, for normal completion, +@samp{?}, for listing completions after successive tabs, +@samp{!}, for listing alternatives on partial word completion, +@samp{@@}, to list completions if the word is not unmodified, +or +@samp{%}, for menu completion. +This variable is available only in shell functions and external +commands invoked by the +programmable completion facilities (@pxref{Programmable Completion}). + +@item COMP_KEY +The key (or final key of a key sequence) used to invoke the current +completion function. + +@item COMP_WORDBREAKS +The set of characters that the Readline library treats as word +separators when performing word completion. +If @code{COMP_WORDBREAKS} is unset, it loses its special properties, +even if it is subsequently reset. + +@item COMP_WORDS +An array variable consisting of the individual +words in the current command line. +The line is split into words as Readline would split it, using +@code{COMP_WORDBREAKS} as described above. +This variable is available only in shell functions invoked by the +programmable completion facilities (@pxref{Programmable Completion}). + +@item COMPREPLY +An array variable from which Bash reads the possible completions +generated by a shell function invoked by the programmable completion +facility (@pxref{Programmable Completion}). +Each array element contains one possible completion. + +@item COPROC +An array variable created to hold the file descriptors +for output from and input to an unnamed coprocess (@pxref{Coprocesses}). + +@item DIRSTACK +An array variable containing the current contents of the directory stack. +Directories appear in the stack in the order they are displayed by the +@code{dirs} builtin. +Assigning to members of this array variable may be used to modify +directories already in the stack, but the @code{pushd} and @code{popd} +builtins must be used to add and remove directories. +Assignment to this variable will not change the current directory. +If @env{DIRSTACK} is unset, it loses its special properties, even if +it is subsequently reset. + +@item EMACS +If Bash finds this variable in the environment when the shell +starts with value @samp{t}, it assumes that the shell is running in an +Emacs shell buffer and disables line editing. + +@item ENV +Similar to @code{BASH_ENV}; used when the shell is invoked in +@sc{posix} Mode (@pxref{Bash POSIX Mode}). + +@item EUID +The numeric effective user id of the current user. This variable +is readonly. + +@item FCEDIT +The editor used as a default by the @option{-e} option to the @code{fc} +builtin command. + +@item FIGNORE +A colon-separated list of suffixes to ignore when performing +filename completion. +A filename whose suffix matches one of the entries in +@env{FIGNORE} +is excluded from the list of matched filenames. A sample +value is @samp{.o:~} + +@item FUNCNAME +An array variable containing the names of all shell functions +currently in the execution call stack. +The element with index 0 is the name of any currently-executing +shell function. +The bottom-most element (the one with the highest index) +is @code{"main"}. +This variable exists only when a shell function is executing. +Assignments to @env{FUNCNAME} have no effect and return an error status. +If @env{FUNCNAME} is unset, it loses its special properties, even if +it is subsequently reset. + +This variable can be used with @code{BASH_LINENO} and @code{BASH_SOURCE}. +Each element of @code{FUNCNAME} has corresponding elements in +@code{BASH_LINENO} and @code{BASH_SOURCE} to describe the call stack. +For instance, @code{$@{FUNCNAME[$i]@}} was called from the file +@code{$@{BASH_SOURCE[$i+1]@}} at line number @code{$@{BASH_LINENO[$i]@}}. +The @code{caller} builtin displays the current call stack using this +information. + +@item FUNCNEST +If set to a numeric value greater than 0, defines a maximum function +nesting level. Function invocations that exceed this nesting level +will cause the current command to abort. + +@item GLOBIGNORE +A colon-separated list of patterns defining the set of filenames to +be ignored by filename expansion. +If a filename matched by a filename expansion pattern also matches one +of the patterns in @env{GLOBIGNORE}, it is removed from the list +of matches. + +@item GROUPS +An array variable containing the list of groups of which the current +user is a member. +Assignments to @env{GROUPS} have no effect and return an error status. +If @env{GROUPS} is unset, it loses its special properties, even if it is +subsequently reset. + +@item histchars +Up to three characters which control history expansion, quick +substitution, and tokenization (@pxref{History Interaction}). +The first character is the +@var{history expansion} character, that is, the character which signifies the +start of a history expansion, normally @samp{!}. The second character is the +character which signifies `quick substitution' when seen as the first +character on a line, normally @samp{^}. The optional third character is the +character which indicates that the remainder of the line is a comment when +found as the first character of a word, usually @samp{#}. The history +comment character causes history substitution to be skipped for the +remaining words on the line. It does not necessarily cause the shell +parser to treat the rest of the line as a comment. + +@item HISTCMD +The history number, or index in the history list, of the current +command. If @env{HISTCMD} is unset, it loses its special properties, +even if it is subsequently reset. + +@item HISTCONTROL +A colon-separated list of values controlling how commands are saved on +the history list. +If the list of values includes @samp{ignorespace}, lines which begin +with a space character are not saved in the history list. +A value of @samp{ignoredups} causes lines which match the previous +history entry to not be saved. +A value of @samp{ignoreboth} is shorthand for +@samp{ignorespace} and @samp{ignoredups}. +A value of @samp{erasedups} causes all previous lines matching the +current line to be removed from the history list before that line +is saved. +Any value not in the above list is ignored. +If @env{HISTCONTROL} is unset, or does not include a valid value, +all lines read by the shell parser are saved on the history list, +subject to the value of @env{HISTIGNORE}. +The second and subsequent lines of a multi-line compound command are +not tested, and are added to the history regardless of the value of +@env{HISTCONTROL}. + +@item HISTFILE +The name of the file to which the command history is saved. The +default value is @file{~/.bash_history}. + +@item HISTFILESIZE +The maximum number of lines contained in the history file. +When this variable is assigned a value, the history file is truncated, +if necessary, to contain no more than that number of lines +by removing the oldest entries. +The history file is also truncated to this size after +writing it when a shell exits. +If the value is 0, the history file is truncated to zero size. +Non-numeric values and numeric values less than zero inhibit truncation. +The shell sets the default value to the value of @env{HISTSIZE} +after reading any startup files. + +@item HISTIGNORE +A colon-separated list of patterns used to decide which command +lines should be saved on the history list. Each pattern is +anchored at the beginning of the line and must match the complete +line (no implicit @samp{*} is appended). Each pattern is tested +against the line after the checks specified by @env{HISTCONTROL} +are applied. In addition to the normal shell pattern matching +characters, @samp{&} matches the previous history line. @samp{&} +may be escaped using a backslash; the backslash is removed +before attempting a match. +The second and subsequent lines of a multi-line compound command are +not tested, and are added to the history regardless of the value of +@env{HISTIGNORE}. + +@env{HISTIGNORE} subsumes the function of @env{HISTCONTROL}. A +pattern of @samp{&} is identical to @code{ignoredups}, and a +pattern of @samp{[ ]*} is identical to @code{ignorespace}. +Combining these two patterns, separating them with a colon, +provides the functionality of @code{ignoreboth}. + +@item HISTSIZE +The maximum number of commands to remember on the history list. +If the value is 0, commands are not saved in the history list. +Numeric values less than zero result in every command being saved +on the history list (there is no limit). +The shell sets the default value to 500 after reading any startup files. + +@item HISTTIMEFORMAT +If this variable is set and not null, its value is used as a format string +for @var{strftime} to print the time stamp associated with each history +entry displayed by the @code{history} builtin. +If this variable is set, time stamps are written to the history file so +they may be preserved across shell sessions. +This uses the history comment character to distinguish timestamps from +other history lines. + +@item HOSTFILE +Contains the name of a file in the same format as @file{/etc/hosts} that +should be read when the shell needs to complete a hostname. +The list of possible hostname completions may be changed while the shell +is running; +the next time hostname completion is attempted after the +value is changed, Bash adds the contents of the new file to the +existing list. +If @env{HOSTFILE} is set, but has no value, or does not name a readable file, +Bash attempts to read +@file{/etc/hosts} to obtain the list of possible hostname completions. +When @env{HOSTFILE} is unset, the hostname list is cleared. + +@item HOSTNAME +The name of the current host. + +@item HOSTTYPE +A string describing the machine Bash is running on. + +@item IGNOREEOF +Controls the action of the shell on receipt of an @code{EOF} character +as the sole input. If set, the value denotes the number +of consecutive @code{EOF} characters that can be read as the +first character on an input line +before the shell will exit. If the variable exists but does not +have a numeric value (or has no value) then the default is 10. +If the variable does not exist, then @code{EOF} signifies the end of +input to the shell. This is only in effect for interactive shells. + +@item INPUTRC +The name of the Readline initialization file, overriding the default +of @file{~/.inputrc}. + +@item LANG +Used to determine the locale category for any category not specifically +selected with a variable starting with @code{LC_}. + +@item LC_ALL +This variable overrides the value of @env{LANG} and any other +@code{LC_} variable specifying a locale category. + +@item LC_COLLATE +This variable determines the collation order used when sorting the +results of filename expansion, and +determines the behavior of range expressions, equivalence classes, +and collating sequences within filename expansion and pattern matching +(@pxref{Filename Expansion}). + +@item LC_CTYPE +This variable determines the interpretation of characters and the +behavior of character classes within filename expansion and pattern +matching (@pxref{Filename Expansion}). + +@item LC_MESSAGES +This variable determines the locale used to translate double-quoted +strings preceded by a @samp{$} (@pxref{Locale Translation}). + +@item LC_NUMERIC +This variable determines the locale category used for number formatting. + +@item LINENO +The line number in the script or shell function currently executing. + +@item LINES +Used by the @code{select} command to determine the column length +for printing selection lists. +Automatically set if the @code{checkwinsize} option is enabled +(@pxref{The Shopt Builtin}), or in an interactive shell upon receipt of a +@code{SIGWINCH}. + +@item MACHTYPE +A string that fully describes the system type on which Bash +is executing, in the standard @sc{gnu} @var{cpu-company-system} format. + +@item MAILCHECK +How often (in seconds) that the shell should check for mail in the +files specified in the @env{MAILPATH} or @env{MAIL} variables. +The default is 60 seconds. When it is time to check +for mail, the shell does so before displaying the primary prompt. +If this variable is unset, or set to a value that is not a number +greater than or equal to zero, the shell disables mail checking. + +@item MAPFILE +An array variable created to hold the text read by the +@code{mapfile} builtin when no variable name is supplied. + +@item OLDPWD +The previous working directory as set by the @code{cd} builtin. + +@item OPTERR +If set to the value 1, Bash displays error messages +generated by the @code{getopts} builtin command. + +@item OSTYPE +A string describing the operating system Bash is running on. + +@item PIPESTATUS +An array variable (@pxref{Arrays}) +containing a list of exit status values from the processes +in the most-recently-executed foreground pipeline (which may +contain only a single command). + +@item POSIXLY_CORRECT +If this variable is in the environment when Bash starts, the shell +enters @sc{posix} mode (@pxref{Bash POSIX Mode}) before reading the +startup files, as if the @option{--posix} invocation option had been supplied. +If it is set while the shell is running, Bash enables @sc{posix} mode, +as if the command +@example +@code{set -o posix} +@end example +@noindent +had been executed. + +@item PPID +The process @sc{id} of the shell's parent process. This variable +is readonly. + +@item PROMPT_COMMAND +If set, the value is interpreted as a command to execute +before the printing of each primary prompt (@env{$PS1}). + +@item PROMPT_DIRTRIM +If set to a number greater than zero, the value is used as the number of +trailing directory components to retain when expanding the @code{\w} and +@code{\W} prompt string escapes (@pxref{Controlling the Prompt}). +Characters removed are replaced with an ellipsis. + +@item PS3 +The value of this variable is used as the prompt for the +@code{select} command. If this variable is not set, the +@code{select} command prompts with @samp{#? } + +@item PS4 +The value is the prompt printed before the command line is echoed +when the @option{-x} option is set (@pxref{The Set Builtin}). +The first character of @env{PS4} is replicated multiple times, as +necessary, to indicate multiple levels of indirection. +The default is @samp{+ }. + +@item PWD +The current working directory as set by the @code{cd} builtin. + +@item RANDOM +Each time this parameter is referenced, a random integer +between 0 and 32767 is generated. Assigning a value to this +variable seeds the random number generator. + +@item READLINE_LINE +The contents of the Readline line buffer, for use +with @samp{bind -x} (@pxref{Bash Builtins}). + +@item READLINE_POINT +The position of the insertion point in the Readline line buffer, for use +with @samp{bind -x} (@pxref{Bash Builtins}). + +@item REPLY +The default variable for the @code{read} builtin. + +@item SECONDS +This variable expands to the number of seconds since the +shell was started. Assignment to this variable resets +the count to the value assigned, and the expanded value +becomes the value assigned plus the number of seconds +since the assignment. + +@item SHELL +The full pathname to the shell is kept in this environment variable. +If it is not set when the shell starts, +Bash assigns to it the full pathname of the current user's login shell. + +@item SHELLOPTS +A colon-separated list of enabled shell options. Each word in +the list is a valid argument for the @option{-o} option to the +@code{set} builtin command (@pxref{The Set Builtin}). +The options appearing in @env{SHELLOPTS} are those reported +as @samp{on} by @samp{set -o}. +If this variable is in the environment when Bash +starts up, each shell option in the list will be enabled before +reading any startup files. This variable is readonly. + +@item SHLVL +Incremented by one each time a new instance of Bash is started. This is +intended to be a count of how deeply your Bash shells are nested. + +@item TIMEFORMAT +The value of this parameter is used as a format string specifying +how the timing information for pipelines prefixed with the @code{time} +reserved word should be displayed. +The @samp{%} character introduces an +escape sequence that is expanded to a time value or other +information. +The escape sequences and their meanings are as +follows; the braces denote optional portions. + +@table @code + +@item %% +A literal @samp{%}. + +@item %[@var{p}][l]R +The elapsed time in seconds. + +@item %[@var{p}][l]U +The number of CPU seconds spent in user mode. + +@item %[@var{p}][l]S +The number of CPU seconds spent in system mode. + +@item %P +The CPU percentage, computed as (%U + %S) / %R. +@end table + +The optional @var{p} is a digit specifying the precision, the number of +fractional digits after a decimal point. +A value of 0 causes no decimal point or fraction to be output. +At most three places after the decimal point may be specified; values +of @var{p} greater than 3 are changed to 3. +If @var{p} is not specified, the value 3 is used. + +The optional @code{l} specifies a longer format, including minutes, of +the form @var{MM}m@var{SS}.@var{FF}s. +The value of @var{p} determines whether or not the fraction is included. + +If this variable is not set, Bash acts as if it had the value +@example +@code{$'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'} +@end example +If the value is null, no timing information is displayed. +A trailing newline is added when the format string is displayed. + +@item TMOUT +If set to a value greater than zero, @code{TMOUT} is treated as the +default timeout for the @code{read} builtin (@pxref{Bash Builtins}). +The @code{select} command (@pxref{Conditional Constructs}) terminates +if input does not arrive after @code{TMOUT} seconds when input is coming +from a terminal. + +In an interactive shell, the value is interpreted as +the number of seconds to wait for a line of input after issuing +the primary prompt. +Bash +terminates after waiting for that number of seconds if a complete +line of input does not arrive. + +@item TMPDIR +If set, Bash uses its value as the name of a directory in which +Bash creates temporary files for the shell's use. + +@item UID +The numeric real user id of the current user. This variable is readonly. + +@end vtable + +@node Bash Features +@chapter Bash Features + +This chapter describes features unique to Bash. + +@menu +* Invoking Bash:: Command line options that you can give + to Bash. +* Bash Startup Files:: When and how Bash executes scripts. +* Interactive Shells:: What an interactive shell is. +* Bash Conditional Expressions:: Primitives used in composing expressions for + the @code{test} builtin. +* Shell Arithmetic:: Arithmetic on shell variables. +* Aliases:: Substituting one command for another. +* Arrays:: Array Variables. +* The Directory Stack:: History of visited directories. +* Controlling the Prompt:: Customizing the various prompt strings. +* The Restricted Shell:: A more controlled mode of shell execution. +* Bash POSIX Mode:: Making Bash behave more closely to what + the POSIX standard specifies. +@end menu + +@node Invoking Bash +@section Invoking Bash + +@example +bash [long-opt] [-ir] [-abefhkmnptuvxdBCDHP] [-o @var{option}] [-O @var{shopt_option}] [@var{argument} @dots{}] +bash [long-opt] [-abefhkmnptuvxdBCDHP] [-o @var{option}] [-O @var{shopt_option}] -c @var{string} [@var{argument} @dots{}] +bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o @var{option}] [-O @var{shopt_option}] [@var{argument} @dots{}] +@end example + +All of the single-character options used with the @code{set} builtin +(@pxref{The Set Builtin}) can be used as options when the shell is invoked. +In addition, there are several multi-character +options that you can use. These options must appear on the command +line before the single-character options to be recognized. + +@table @code +@item --debugger +Arrange for the debugger profile to be executed before the shell +starts. Turns on extended debugging mode (see @ref{The Shopt Builtin} +for a description of the @code{extdebug} option to the @code{shopt} +builtin). + +@item --dump-po-strings +A list of all double-quoted strings preceded by @samp{$} +is printed on the standard output +in the @sc{gnu} @code{gettext} PO (portable object) file format. +Equivalent to @option{-D} except for the output format. + +@item --dump-strings +Equivalent to @option{-D}. + +@item --help +Display a usage message on standard output and exit successfully. + +@item --init-file @var{filename} +@itemx --rcfile @var{filename} +Execute commands from @var{filename} (instead of @file{~/.bashrc}) +in an interactive shell. + +@item --login +Equivalent to @option{-l}. + +@item --noediting +Do not use the @sc{gnu} Readline library (@pxref{Command Line Editing}) +to read command lines when the shell is interactive. + +@item --noprofile +Don't load the system-wide startup file @file{/etc/profile} +or any of the personal initialization files +@file{~/.bash_profile}, @file{~/.bash_login}, or @file{~/.profile} +when Bash is invoked as a login shell. + +@item --norc +Don't read the @file{~/.bashrc} initialization file in an +interactive shell. This is on by default if the shell is +invoked as @code{sh}. + +@item --posix +Change the behavior of Bash where the default operation differs +from the @sc{posix} standard to match the standard. This +is intended to make Bash behave as a strict superset of that +standard. @xref{Bash POSIX Mode}, for a description of the Bash +@sc{posix} mode. + +@item --restricted +Make the shell a restricted shell (@pxref{The Restricted Shell}). + +@item --verbose +Equivalent to @option{-v}. Print shell input lines as they're read. + +@item --version +Show version information for this instance of +Bash on the standard output and exit successfully. +@end table + +There are several single-character options that may be supplied at +invocation which are not available with the @code{set} builtin. + +@table @code +@item -c +Read and execute commands from the first non-option argument +@var{command_string}, then exit. +If there are arguments after the @var{command_string}, +the first argument is assigned to @code{$0} +and any remaining arguments are assigned to the positional parameters. +The assignment to @code{$0} sets the name of the shell, which is used +in warning and error messages. + +@item -i +Force the shell to run interactively. Interactive shells are +described in @ref{Interactive Shells}. + +@item -l +Make this shell act as if it had been directly invoked by login. +When the shell is interactive, this is equivalent to starting a +login shell with @samp{exec -l bash}. +When the shell is not interactive, the login shell startup files will +be executed. +@samp{exec bash -l} or @samp{exec bash --login} +will replace the current shell with a Bash login shell. +@xref{Bash Startup Files}, for a description of the special behavior +of a login shell. + +@item -r +Make the shell a restricted shell (@pxref{The Restricted Shell}). + +@item -s +If this option is present, or if no arguments remain after option +processing, then commands are read from the standard input. +This option allows the positional parameters to be set +when invoking an interactive shell. + +@item -D +A list of all double-quoted strings preceded by @samp{$} +is printed on the standard output. +These are the strings that +are subject to language translation when the current locale +is not @code{C} or @code{POSIX} (@pxref{Locale Translation}). +This implies the @option{-n} option; no commands will be executed. + +@item [-+]O [@var{shopt_option}] +@var{shopt_option} is one of the shell options accepted by the +@code{shopt} builtin (@pxref{The Shopt Builtin}). +If @var{shopt_option} is present, @option{-O} sets the value of that option; +@option{+O} unsets it. +If @var{shopt_option} is not supplied, the names and values of the shell +options accepted by @code{shopt} are printed on the standard output. +If the invocation option is @option{+O}, the output is displayed in a format +that may be reused as input. + +@item -- +A @code{--} signals the end of options and disables further option +processing. +Any arguments after the @code{--} are treated as filenames and arguments. +@end table + +@cindex login shell +A @emph{login} shell is one whose first character of argument zero is +@samp{-}, or one invoked with the @option{--login} option. + +@cindex interactive shell +An @emph{interactive} shell is one started without non-option arguments, +unless @option{-s} is specified, +without specifying the @option{-c} option, and whose input and output are both +connected to terminals (as determined by @code{isatty(3)}), or one +started with the @option{-i} option. @xref{Interactive Shells}, for more +information. + +If arguments remain after option processing, and neither the +@option{-c} nor the @option{-s} +option has been supplied, the first argument is assumed to +be the name of a file containing shell commands (@pxref{Shell Scripts}). +When Bash is invoked in this fashion, @code{$0} +is set to the name of the file, and the positional parameters +are set to the remaining arguments. +Bash reads and executes commands from this file, then exits. +Bash's exit status is the exit status of the last command executed +in the script. If no commands are executed, the exit status is 0. + +@node Bash Startup Files +@section Bash Startup Files +@cindex startup files + +This section describes how Bash executes its startup files. +If any of the files exist but cannot be read, Bash reports an error. +Tildes are expanded in filenames as described above under +Tilde Expansion (@pxref{Tilde Expansion}). + +Interactive shells are described in @ref{Interactive Shells}. + +@subsubheading Invoked as an interactive login shell, or with @option{--login} + +When Bash is invoked as an interactive login shell, or as a +non-interactive shell with the @option{--login} option, it first reads and +executes commands from the file @file{/etc/profile}, if that file exists. +After reading that file, it looks for @file{~/.bash_profile}, +@file{~/.bash_login}, and @file{~/.profile}, in that order, and reads +and executes commands from the first one that exists and is readable. +The @option{--noprofile} option may be used when the shell is started to +inhibit this behavior. + +When a login shell exits, Bash reads and executes commands from +the file @file{~/.bash_logout}, if it exists. + +@subsubheading Invoked as an interactive non-login shell + +When an interactive shell that is not a login shell is started, Bash +reads and executes commands from @file{~/.bashrc}, if that file exists. +This may be inhibited by using the @option{--norc} option. +The @option{--rcfile @var{file}} option will force Bash to read and +execute commands from @var{file} instead of @file{~/.bashrc}. + +So, typically, your @file{~/.bash_profile} contains the line +@example +@code{if [ -f ~/.bashrc ]; then . ~/.bashrc; fi} +@end example +@noindent +after (or before) any login-specific initializations. + +@subsubheading Invoked non-interactively + +When Bash is started non-interactively, to run a shell script, +for example, it looks for the variable @env{BASH_ENV} in the environment, +expands its value if it appears there, and uses the expanded value as +the name of a file to read and execute. Bash behaves as if the +following command were executed: +@example +@code{if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi} +@end example +@noindent +but the value of the @env{PATH} variable is not used to search for the +filename. + +As noted above, if a non-interactive shell is invoked with the +@option{--login} option, Bash attempts to read and execute commands from the +login shell startup files. + +@subsubheading Invoked with name @code{sh} + +If Bash is invoked with the name @code{sh}, it tries to mimic the +startup behavior of historical versions of @code{sh} as closely as +possible, while conforming to the @sc{posix} standard as well. + +When invoked as an interactive login shell, or as a non-interactive +shell with the @option{--login} option, it first attempts to read +and execute commands from @file{/etc/profile} and @file{~/.profile}, in +that order. +The @option{--noprofile} option may be used to inhibit this behavior. +When invoked as an interactive shell with the name @code{sh}, Bash +looks for the variable @env{ENV}, expands its value if it is defined, +and uses the expanded value as the name of a file to read and execute. +Since a shell invoked as @code{sh} does not attempt to read and execute +commands from any other startup files, the @option{--rcfile} option has +no effect. +A non-interactive shell invoked with the name @code{sh} does not attempt +to read any other startup files. + +When invoked as @code{sh}, Bash enters @sc{posix} mode after +the startup files are read. + +@subsubheading Invoked in @sc{posix} mode + +When Bash is started in @sc{posix} mode, as with the +@option{--posix} command line option, it follows the @sc{posix} standard +for startup files. +In this mode, interactive shells expand the @env{ENV} variable +and commands are read and executed from the file whose name is the +expanded value. +No other startup files are read. + +@subsubheading Invoked by remote shell daemon + +Bash attempts to determine when it is being run with its standard input +connected to a network connection, as when executed by the remote shell +daemon, usually @code{rshd}, or the secure shell daemon @code{sshd}. +If Bash determines it is being run in +this fashion, it reads and executes commands from @file{~/.bashrc}, if that +file exists and is readable. +It will not do this if invoked as @code{sh}. +The @option{--norc} option may be used to inhibit this behavior, and the +@option{--rcfile} option may be used to force another file to be read, but +neither @code{rshd} nor @code{sshd} generally invoke the shell with those +options or allow them to be specified. + +@subsubheading Invoked with unequal effective and real @sc{uid/gid}s + +If Bash is started with the effective user (group) id not equal to the +real user (group) id, and the @option{-p} option is not supplied, no startup +files are read, shell functions are not inherited from the environment, +the @env{SHELLOPTS}, @env{BASHOPTS}, @env{CDPATH}, and @env{GLOBIGNORE} +variables, if they appear in the environment, are ignored, and the effective +user id is set to the real user id. +If the @option{-p} option is supplied at invocation, the startup behavior is +the same, but the effective user id is not reset. + +@node Interactive Shells +@section Interactive Shells +@cindex interactive shell +@cindex shell, interactive + +@menu +* What is an Interactive Shell?:: What determines whether a shell is Interactive. +* Is this Shell Interactive?:: How to tell if a shell is interactive. +* Interactive Shell Behavior:: What changes in a interactive shell? +@end menu + +@node What is an Interactive Shell? +@subsection What is an Interactive Shell? + +An interactive shell +is one started without non-option arguments, unless @option{-s} is +specified, without specifying the @option{-c} option, and +whose input and error output are both +connected to terminals (as determined by @code{isatty(3)}), +or one started with the @option{-i} option. + +An interactive shell generally reads from and writes to a user's +terminal. + +The @option{-s} invocation option may be used to set the positional parameters +when an interactive shell is started. + +@node Is this Shell Interactive? +@subsection Is this Shell Interactive? + +To determine within a startup script whether or not Bash is +running interactively, +test the value of the @samp{-} special parameter. +It contains @code{i} when the shell is interactive. For example: + +@example +case "$-" in +*i*) echo This shell is interactive ;; +*) echo This shell is not interactive ;; +esac +@end example + +Alternatively, startup scripts may examine the variable +@env{PS1}; it is unset in non-interactive shells, and set in +interactive shells. Thus: + +@example +if [ -z "$PS1" ]; then + echo This shell is not interactive +else + echo This shell is interactive +fi +@end example + +@node Interactive Shell Behavior +@subsection Interactive Shell Behavior + +When the shell is running interactively, it changes its behavior in +several ways. + +@enumerate +@item +Startup files are read and executed as described in @ref{Bash Startup Files}. + +@item +Job Control (@pxref{Job Control}) is enabled by default. When job +control is in effect, Bash ignores the keyboard-generated job control +signals @code{SIGTTIN}, @code{SIGTTOU}, and @code{SIGTSTP}. + +@item +Bash expands and displays @env{PS1} before reading the first line +of a command, and expands and displays @env{PS2} before reading the +second and subsequent lines of a multi-line command. + +@item +Bash executes the value of the @env{PROMPT_COMMAND} variable as a command +before printing the primary prompt, @env{$PS1} +(@pxref{Bash Variables}). + +@item +Readline (@pxref{Command Line Editing}) is used to read commands from +the user's terminal. + +@item +Bash inspects the value of the @code{ignoreeof} option to @code{set -o} +instead of exiting immediately when it receives an @code{EOF} on its +standard input when reading a command (@pxref{The Set Builtin}). + +@item +Command history (@pxref{Bash History Facilities}) +and history expansion (@pxref{History Interaction}) +are enabled by default. +Bash will save the command history to the file named by @env{$HISTFILE} +when a shell with history enabled exits. + +@item +Alias expansion (@pxref{Aliases}) is performed by default. + +@item +In the absence of any traps, Bash ignores @code{SIGTERM} +(@pxref{Signals}). + +@item +In the absence of any traps, @code{SIGINT} is caught and handled +((@pxref{Signals}). +@code{SIGINT} will interrupt some shell builtins. + +@item +An interactive login shell sends a @code{SIGHUP} to all jobs on exit +if the @code{huponexit} shell option has been enabled (@pxref{Signals}). + +@item +The @option{-n} invocation option is ignored, and @samp{set -n} has +no effect (@pxref{The Set Builtin}). + +@item +Bash will check for mail periodically, depending on the values of the +@env{MAIL}, @env{MAILPATH}, and @env{MAILCHECK} shell variables +(@pxref{Bash Variables}). + +@item +Expansion errors due to references to unbound shell variables after +@samp{set -u} has been enabled will not cause the shell to exit +(@pxref{The Set Builtin}). + +@item +The shell will not exit on expansion errors caused by @var{var} being unset +or null in @code{$@{@var{var}:?@var{word}@}} expansions +(@pxref{Shell Parameter Expansion}). + +@item +Redirection errors encountered by shell builtins will not cause the +shell to exit. + +@item +When running in @sc{posix} mode, a special builtin returning an error +status will not cause the shell to exit (@pxref{Bash POSIX Mode}). + +@item +A failed @code{exec} will not cause the shell to exit +(@pxref{Bourne Shell Builtins}). + +@item +Parser syntax errors will not cause the shell to exit. + +@item +Simple spelling correction for directory arguments to the @code{cd} +builtin is enabled by default (see the description of the @code{cdspell} +option to the @code{shopt} builtin in @ref{The Shopt Builtin}). + +@item +The shell will check the value of the @env{TMOUT} variable and exit +if a command is not read within the specified number of seconds after +printing @env{$PS1} (@pxref{Bash Variables}). + +@end enumerate + +@node Bash Conditional Expressions +@section Bash Conditional Expressions +@cindex expressions, conditional + +Conditional expressions are used by the @code{[[} compound command +and the @code{test} and @code{[} builtin commands. + +Expressions may be unary or binary. +Unary expressions are often used to examine the status of a file. +There are string operators and numeric comparison operators as well. +If the @var{file} argument to one of the primaries is of the form +@file{/dev/fd/@var{N}}, then file descriptor @var{N} is checked. +If the @var{file} argument to one of the primaries is one of +@file{/dev/stdin}, @file{/dev/stdout}, or @file{/dev/stderr}, file +descriptor 0, 1, or 2, respectively, is checked. + +When used with @code{[[}, the @samp{<} and @samp{>} operators sort +lexicographically using the current locale. +The @code{test} command uses ASCII ordering. + +Unless otherwise specified, primaries that operate on files follow symbolic +links and operate on the target of the link, rather than the link itself. + +@table @code +@item -a @var{file} +True if @var{file} exists. + +@item -b @var{file} +True if @var{file} exists and is a block special file. + +@item -c @var{file} +True if @var{file} exists and is a character special file. + +@item -d @var{file} +True if @var{file} exists and is a directory. + +@item -e @var{file} +True if @var{file} exists. + +@item -f @var{file} +True if @var{file} exists and is a regular file. + +@item -g @var{file} +True if @var{file} exists and its set-group-id bit is set. + +@item -h @var{file} +True if @var{file} exists and is a symbolic link. + +@item -k @var{file} +True if @var{file} exists and its "sticky" bit is set. + +@item -p @var{file} +True if @var{file} exists and is a named pipe (FIFO). + +@item -r @var{file} +True if @var{file} exists and is readable. + +@item -s @var{file} +True if @var{file} exists and has a size greater than zero. + +@item -t @var{fd} +True if file descriptor @var{fd} is open and refers to a terminal. + +@item -u @var{file} +True if @var{file} exists and its set-user-id bit is set. + +@item -w @var{file} +True if @var{file} exists and is writable. + +@item -x @var{file} +True if @var{file} exists and is executable. + +@item -G @var{file} +True if @var{file} exists and is owned by the effective group id. + +@item -L @var{file} +True if @var{file} exists and is a symbolic link. + +@item -N @var{file} +True if @var{file} exists and has been modified since it was last read. + +@item -O @var{file} +True if @var{file} exists and is owned by the effective user id. + +@item -S @var{file} +True if @var{file} exists and is a socket. + +@item @var{file1} -ef @var{file2} +True if @var{file1} and @var{file2} refer to the same device and +inode numbers. + +@item @var{file1} -nt @var{file2} +True if @var{file1} is newer (according to modification date) +than @var{file2}, or if @var{file1} exists and @var{file2} does not. + +@item @var{file1} -ot @var{file2} +True if @var{file1} is older than @var{file2}, +or if @var{file2} exists and @var{file1} does not. + +@item -o @var{optname} +True if the shell option @var{optname} is enabled. +The list of options appears in the description of the @option{-o} +option to the @code{set} builtin (@pxref{The Set Builtin}). + +@item -v @var{varname} +True if the shell variable @var{varname} is set (has been assigned a value). + +@item -R @var{varname} +True if the shell variable @var{varname} is set and is a name reference. + +@item -z @var{string} +True if the length of @var{string} is zero. + +@item -n @var{string} +@itemx @var{string} +True if the length of @var{string} is non-zero. + +@item @var{string1} == @var{string2} +@itemx @var{string1} = @var{string2} +True if the strings are equal. +When used with the @code{[[} command, this performs pattern matching as +described above (@pxref{Conditional Constructs}). + +@samp{=} should be used with the @code{test} command for @sc{posix} conformance. + +@item @var{string1} != @var{string2} +True if the strings are not equal. + +@item @var{string1} < @var{string2} +True if @var{string1} sorts before @var{string2} lexicographically. + +@item @var{string1} > @var{string2} +True if @var{string1} sorts after @var{string2} lexicographically. + +@item @var{arg1} OP @var{arg2} +@code{OP} is one of +@samp{-eq}, @samp{-ne}, @samp{-lt}, @samp{-le}, @samp{-gt}, or @samp{-ge}. +These arithmetic binary operators return true if @var{arg1} +is equal to, not equal to, less than, less than or equal to, +greater than, or greater than or equal to @var{arg2}, +respectively. @var{Arg1} and @var{arg2} +may be positive or negative integers. +@end table + +@node Shell Arithmetic +@section Shell Arithmetic +@cindex arithmetic, shell +@cindex shell arithmetic +@cindex expressions, arithmetic +@cindex evaluation, arithmetic +@cindex arithmetic evaluation + +The shell allows arithmetic expressions to be evaluated, as one of +the shell expansions or by the @code{let} and the @option{-i} option +to the @code{declare} builtins. + +Evaluation is done in fixed-width integers with no check for overflow, +though division by 0 is trapped and flagged as an error. +The operators and their precedence, associativity, and values +are the same as in the C language. +The following list of operators is grouped into levels of +equal-precedence operators. +The levels are listed in order of decreasing precedence. + +@table @code + +@item @var{id}++ @var{id}-- +variable post-increment and post-decrement + +@item ++@var{id} --@var{id} +variable pre-increment and pre-decrement + +@item - + +unary minus and plus + +@item ! ~ +logical and bitwise negation + +@item ** +exponentiation + +@item * / % +multiplication, division, remainder + +@item + - +addition, subtraction + +@item << >> +left and right bitwise shifts + +@item <= >= < > +comparison + +@item == != +equality and inequality + +@item & +bitwise AND + +@item ^ +bitwise exclusive OR + +@item | +bitwise OR + +@item && +logical AND + +@item || +logical OR + +@item expr ? expr : expr +conditional operator + +@item = *= /= %= += -= <<= >>= &= ^= |= +assignment + +@item expr1 , expr2 +comma +@end table + +Shell variables are allowed as operands; parameter expansion is +performed before the expression is evaluated. +Within an expression, shell variables may also be referenced by name +without using the parameter expansion syntax. +A shell variable that is null or unset evaluates to 0 when referenced +by name without using the parameter expansion syntax. +The value of a variable is evaluated as an arithmetic expression +when it is referenced, or when a variable which has been given the +@var{integer} attribute using @samp{declare -i} is assigned a value. +A null value evaluates to 0. +A shell variable need not have its @var{integer} attribute turned on +to be used in an expression. + +Constants with a leading 0 are interpreted as octal numbers. +A leading @samp{0x} or @samp{0X} denotes hexadecimal. Otherwise, +numbers take the form [@var{base}@code{#}]@var{n}, where the optional @var{base} +is a decimal number between 2 and 64 representing the arithmetic +base, and @var{n} is a number in that base. +If @var{base}@code{#} is omitted, then base 10 is used. +When specifying @var{n}, +he digits greater than 9 are represented by the lowercase letters, +the uppercase letters, @samp{@@}, and @samp{_}, in that order. +If @var{base} is less than or equal to 36, lowercase and uppercase +letters may be used interchangeably to represent numbers between 10 +and 35. + +Operators are evaluated in order of precedence. Sub-expressions in +parentheses are evaluated first and may override the precedence +rules above. + +@node Aliases +@section Aliases +@cindex alias expansion + +@var{Aliases} allow a string to be substituted for a word when it is used +as the first word of a simple command. +The shell maintains a list of aliases that may be set and unset with +the @code{alias} and @code{unalias} builtin commands. + +The first word of each simple command, if unquoted, is checked to see +if it has an alias. +If so, that word is replaced by the text of the alias. +The characters @samp{/}, @samp{$}, @samp{`}, @samp{=} and any of the +shell metacharacters or quoting characters listed above may not appear +in an alias name. +The replacement text may contain any valid +shell input, including shell metacharacters. +The first word of the replacement text is tested for +aliases, but a word that is identical to an alias being expanded +is not expanded a second time. +This means that one may alias @code{ls} to @code{"ls -F"}, +for instance, and Bash does not try to recursively expand the +replacement text. +If the last character of the alias value is a +@var{blank}, then the next command word following the +alias is also checked for alias expansion. + +Aliases are created and listed with the @code{alias} +command, and removed with the @code{unalias} command. + +There is no mechanism for using arguments in the replacement text, +as in @code{csh}. +If arguments are needed, a shell function should be used +(@pxref{Shell Functions}). + +Aliases are not expanded when the shell is not interactive, +unless the @code{expand_aliases} shell option is set using +@code{shopt} (@pxref{The Shopt Builtin}). + +The rules concerning the definition and use of aliases are +somewhat confusing. Bash +always reads at least one complete line +of input before executing any +of the commands on that line. Aliases are expanded when a +command is read, not when it is executed. Therefore, an +alias definition appearing on the same line as another +command does not take effect until the next line of input is read. +The commands following the alias definition +on that line are not affected by the new alias. +This behavior is also an issue when functions are executed. +Aliases are expanded when a function definition is read, +not when the function is executed, because a function definition +is itself a command. As a consequence, aliases +defined in a function are not available until after that +function is executed. To be safe, always put +alias definitions on a separate line, and do not use @code{alias} +in compound commands. + +For almost every purpose, shell functions are preferred over aliases. + +@node Arrays +@section Arrays +@cindex arrays + +Bash provides one-dimensional indexed and associative array variables. +Any variable may be used as an indexed array; +the @code{declare} builtin will explicitly declare an array. +There is no maximum +limit on the size of an array, nor any requirement that members +be indexed or assigned contiguously. +Indexed arrays are referenced using integers (including arithmetic +expressions (@pxref{Shell Arithmetic})) and are zero-based; +associative arrays use arbitrary strings. +Unless otherwise noted, indexed array indices must be non-negative integers. + +An indexed array is created automatically if any variable is assigned to +using the syntax +@example +@var{name}[@var{subscript}]=@var{value} +@end example + +@noindent +The @var{subscript} +is treated as an arithmetic expression that must evaluate to a number. +To explicitly declare an array, use +@example +declare -a @var{name} +@end example +@noindent +The syntax +@example +declare -a @var{name}[@var{subscript}] +@end example +@noindent +is also accepted; the @var{subscript} is ignored. + +@noindent +Associative arrays are created using +@example +declare -A @var{name}. +@end example + +Attributes may be +specified for an array variable using the @code{declare} and +@code{readonly} builtins. Each attribute applies to all members of +an array. + +Arrays are assigned to using compound assignments of the form +@example +@var{name}=(@var{value1} @var{value2} @dots{} ) +@end example +@noindent +where each +@var{value} is of the form @code{[@var{subscript}]=}@var{string}. +Indexed array assignments do not require anything but @var{string}. +When assigning to indexed arrays, if +the optional subscript is supplied, that index is assigned to; +otherwise the index of the element assigned is the last index assigned +to by the statement plus one. Indexing starts at zero. + +When assigning to an associative array, the subscript is required. + +This syntax is also accepted by the @code{declare} +builtin. Individual array elements may be assigned to using the +@code{@var{name}[@var{subscript}]=@var{value}} syntax introduced above. + +When assigning to an indexed array, if @var{name} +is subscripted by a negative number, that number is +interpreted as relative to one greater than the maximum index of +@var{name}, so negative indices count back from the end of the +array, and an index of -1 references the last element. + +Any element of an array may be referenced using +@code{$@{@var{name}[@var{subscript}]@}}. +The braces are required to avoid +conflicts with the shell's filename expansion operators. If the +@var{subscript} is @samp{@@} or @samp{*}, the word expands to all members +of the array @var{name}. These subscripts differ only when the word +appears within double quotes. +If the word is double-quoted, +@code{$@{@var{name}[*]@}} expands to a single word with +the value of each array member separated by the first character of the +@env{IFS} variable, and @code{$@{@var{name}[@@]@}} expands each element of +@var{name} to a separate word. When there are no array members, +@code{$@{@var{name}[@@]@}} expands to nothing. +If the double-quoted expansion occurs within a word, the expansion of +the first parameter is joined with the beginning part of the original +word, and the expansion of the last parameter is joined with the last +part of the original word. +This is analogous to the +expansion of the special parameters @samp{@@} and @samp{*}. +@code{$@{#@var{name}[@var{subscript}]@}} expands to the length of +@code{$@{@var{name}[@var{subscript}]@}}. +If @var{subscript} is @samp{@@} or +@samp{*}, the expansion is the number of elements in the array. +Referencing an array variable without a subscript is equivalent to +referencing with a subscript of 0. +If the @var{subscript} +used to reference an element of an indexed array +evaluates to a number less than zero, it is +interpreted as relative to one greater than the maximum index of the array, +so negative indices count back from the end of the array, +and an index of -1 refers to the last element. + +An array variable is considered set if a subscript has been assigned a +value. The null string is a valid value. + +It is possible to obtain the keys (indices) of an array as well as the values. +$@{!@var{name}[@@]@} and $@{!@var{name}[*]@} expand to the indices +assigned in array variable @var{name}. +The treatment when in double quotes is similar to the expansion of the +special parameters @samp{@@} and @samp{*} within double quotes. + +The @code{unset} builtin is used to destroy arrays. +@code{unset @var{name}[@var{subscript}]} +destroys the array element at index @var{subscript}. +Negative subscripts to indexed arrays are interpreted as described above. +Care must be taken to avoid unwanted side effects caused by filename +expansion. +@code{unset @var{name}}, where @var{name} is an array, removes the +entire array. A subscript of @samp{*} or @samp{@@} also removes the +entire array. + +The @code{declare}, @code{local}, and @code{readonly} +builtins each accept a @option{-a} option to specify an indexed +array and a @option{-A} option to specify an associative array. +If both options are supplied, @option{-A} takes precedence. +The @code{read} builtin accepts a @option{-a} +option to assign a list of words read from the standard input +to an array, and can read values from the standard input into +individual array elements. The @code{set} and @code{declare} +builtins display array values in a way that allows them to be +reused as input. + +@node The Directory Stack +@section The Directory Stack +@cindex directory stack + +@menu +* Directory Stack Builtins:: Bash builtin commands to manipulate + the directory stack. +@end menu + +The directory stack is a list of recently-visited directories. The +@code{pushd} builtin adds directories to the stack as it changes +the current directory, and the @code{popd} builtin removes specified +directories from the stack and changes the current directory to +the directory removed. The @code{dirs} builtin displays the contents +of the directory stack. + +The contents of the directory stack are also visible +as the value of the @env{DIRSTACK} shell variable. + +@node Directory Stack Builtins +@subsection Directory Stack Builtins + +@table @code + +@item dirs +@btindex dirs +@example +dirs [-clpv] [+@var{N} | -@var{N}] +@end example + +Display the list of currently remembered directories. Directories +are added to the list with the @code{pushd} command; the +@code{popd} command removes directories from the list. + +@table @code +@item -c +Clears the directory stack by deleting all of the elements. +@item -l +Produces a listing using full pathnames; +the default listing format uses a tilde to denote the home directory. +@item -p +Causes @code{dirs} to print the directory stack with one entry per +line. +@item -v +Causes @code{dirs} to print the directory stack with one entry per +line, prefixing each entry with its index in the stack. +@item +@var{N} +Displays the @var{N}th directory (counting from the left of the +list printed by @code{dirs} when invoked without options), starting +with zero. +@item -@var{N} +Displays the @var{N}th directory (counting from the right of the +list printed by @code{dirs} when invoked without options), starting +with zero. +@end table + +@item popd +@btindex popd +@example +popd [-n] [+@var{N} | -@var{N}] +@end example + +Remove the top entry from the directory stack, and @code{cd} +to the new top directory. +When no arguments are given, @code{popd} +removes the top directory from the stack and +performs a @code{cd} to the new top directory. The +elements are numbered from 0 starting at the first directory listed with +@code{dirs}; that is, @code{popd} is equivalent to @code{popd +0}. + +@table @code +@item -n +Suppresses the normal change of directory when removing directories +from the stack, so that only the stack is manipulated. +@item +@var{N} +Removes the @var{N}th directory (counting from the left of the +list printed by @code{dirs}), starting with zero. +@item -@var{N} +Removes the @var{N}th directory (counting from the right of the +list printed by @code{dirs}), starting with zero. +@end table + +@btindex pushd +@item pushd +@example +pushd [-n] [@var{+N} | @var{-N} | @var{dir}] +@end example + +Save the current directory on the top of the directory stack +and then @code{cd} to @var{dir}. +With no arguments, @code{pushd} exchanges the top two directories. + +@table @code +@item -n +Suppresses the normal change of directory when adding directories +to the stack, so that only the stack is manipulated. +@item +@var{N} +Brings the @var{N}th directory (counting from the left of the +list printed by @code{dirs}, starting with zero) to the top of +the list by rotating the stack. +@item -@var{N} +Brings the @var{N}th directory (counting from the right of the +list printed by @code{dirs}, starting with zero) to the top of +the list by rotating the stack. +@item @var{dir} +Makes the current working directory be the top of the stack, making +it the new current directory as if it had been supplied as an argument +to the @code{cd} builtin. +@end table +@end table + +@node Controlling the Prompt +@section Controlling the Prompt +@cindex prompting + +The value of the variable @env{PROMPT_COMMAND} is examined just before +Bash prints each primary prompt. If @env{PROMPT_COMMAND} is set and +has a non-null value, then the +value is executed just as if it had been typed on the command line. + +In addition, the following table describes the special characters which +can appear in the prompt variables @env{PS1} to @env{PS4}: + +@table @code +@item \a +A bell character. +@item \d +The date, in "Weekday Month Date" format (e.g., "Tue May 26"). +@item \D@{@var{format}@} +The @var{format} is passed to @code{strftime}(3) and the result is inserted +into the prompt string; an empty @var{format} results in a locale-specific +time representation. The braces are required. +@item \e +An escape character. +@item \h +The hostname, up to the first `.'. +@item \H +The hostname. +@item \j +The number of jobs currently managed by the shell. +@item \l +The basename of the shell's terminal device name. +@item \n +A newline. +@item \r +A carriage return. +@item \s +The name of the shell, the basename of @code{$0} (the portion +following the final slash). +@item \t +The time, in 24-hour HH:MM:SS format. +@item \T +The time, in 12-hour HH:MM:SS format. +@item \@@ +The time, in 12-hour am/pm format. +@item \A +The time, in 24-hour HH:MM format. +@item \u +The username of the current user. +@item \v +The version of Bash (e.g., 2.00) +@item \V +The release of Bash, version + patchlevel (e.g., 2.00.0) +@item \w +The current working directory, with @env{$HOME} abbreviated with a tilde +(uses the @env{$PROMPT_DIRTRIM} variable). +@item \W +The basename of @env{$PWD}, with @env{$HOME} abbreviated with a tilde. +@item \! +The history number of this command. +@item \# +The command number of this command. +@item \$ +If the effective uid is 0, @code{#}, otherwise @code{$}. +@item \@var{nnn} +The character whose ASCII code is the octal value @var{nnn}. +@item \\ +A backslash. +@item \[ +Begin a sequence of non-printing characters. This could be used to +embed a terminal control sequence into the prompt. +@item \] +End a sequence of non-printing characters. +@end table + +The command number and the history number are usually different: +the history number of a command is its position in the history +list, which may include commands restored from the history file +(@pxref{Bash History Facilities}), while the command number is +the position in the sequence of commands executed during the current +shell session. + +After the string is decoded, it is expanded via +parameter expansion, command substitution, arithmetic +expansion, and quote removal, subject to the value of the +@code{promptvars} shell option (@pxref{Bash Builtins}). + +@node The Restricted Shell +@section The Restricted Shell +@cindex restricted shell + +If Bash is started with the name @code{rbash}, or the +@option{--restricted} +or +@option{-r} +option is supplied at invocation, the shell becomes restricted. +A restricted shell is used to +set up an environment more controlled than the standard shell. +A restricted shell behaves identically to @code{bash} +with the exception that the following are disallowed or not performed: + +@itemize @bullet +@item +Changing directories with the @code{cd} builtin. +@item +Setting or unsetting the values of the @env{SHELL}, @env{PATH}, +@env{ENV}, or @env{BASH_ENV} variables. +@item +Specifying command names containing slashes. +@item +Specifying a filename containing a slash as an argument to the @code{.} +builtin command. +@item +Specifying a filename containing a slash as an argument to the @option{-p} +option to the @code{hash} builtin command. +@item +Importing function definitions from the shell environment at startup. +@item +Parsing the value of @env{SHELLOPTS} from the shell environment at startup. +@item +Redirecting output using the @samp{>}, @samp{>|}, @samp{<>}, @samp{>&}, +@samp{&>}, and @samp{>>} redirection operators. +@item +Using the @code{exec} builtin to replace the shell with another command. +@item +Adding or deleting builtin commands with the +@option{-f} and @option{-d} options to the @code{enable} builtin. +@item +Using the @code{enable} builtin command to enable disabled shell builtins. +@item +Specifying the @option{-p} option to the @code{command} builtin. +@item +Turning off restricted mode with @samp{set +r} or @samp{set +o restricted}. +@end itemize + +These restrictions are enforced after any startup files are read. + +When a command that is found to be a shell script is executed +(@pxref{Shell Scripts}), @code{rbash} turns off any restrictions in +the shell spawned to execute the script. + +@node Bash POSIX Mode +@section Bash POSIX Mode +@cindex POSIX Mode + +Starting Bash with the @option{--posix} command-line option or executing +@samp{set -o posix} while Bash is running will cause Bash to conform more +closely to the @sc{posix} standard by changing the behavior to +match that specified by @sc{posix} in areas where the Bash default differs. + +When invoked as @code{sh}, Bash enters @sc{posix} mode after reading the +startup files. + +The following list is what's changed when `@sc{posix} mode' is in effect: + +@enumerate +@item +When a command in the hash table no longer exists, Bash will re-search +@env{$PATH} to find the new location. This is also available with +@samp{shopt -s checkhash}. + +@item +The message printed by the job control code and builtins when a job +exits with a non-zero status is `Done(status)'. + +@item +The message printed by the job control code and builtins when a job +is stopped is `Stopped(@var{signame})', where @var{signame} is, for +example, @code{SIGTSTP}. + +@item +The @code{bg} builtin uses the required format to describe each job placed +in the background, which does not include an indication of whether the job +is the current or previous job. + +@item +Reserved words appearing in a context where reserved words are recognized +do not undergo alias expansion. + +@item +The @sc{posix} @env{PS1} and @env{PS2} expansions of @samp{!} to +the history number and @samp{!!} to @samp{!} are enabled, +and parameter expansion is performed on the values of @env{PS1} and +@env{PS2} regardless of the setting of the @code{promptvars} option. + +@item +The @sc{posix} startup files are executed (@env{$ENV}) rather than +the normal Bash files. + +@item +Tilde expansion is only performed on assignments preceding a command +name, rather than on all assignment statements on the line. + +@item +The @code{command} builtin does not prevent builtins that take assignment +statements as arguments from expanding them as assignment statements; +when not in @sc{posix} mode, assignment builtins lose their assignment +statement expansion properties when preceded by @code{command}. + +@item +The default history file is @file{~/.sh_history} (this is the +default value of @env{$HISTFILE}). + +@item +The output of @samp{kill -l} prints all the signal names on a single line, +separated by spaces, without the @samp{SIG} prefix. + +@item +The @code{kill} builtin does not accept signal names with a @samp{SIG} +prefix. + +@item +Non-interactive shells exit if @var{filename} in @code{.} @var{filename} +is not found. + +@item +Non-interactive shells exit if a syntax error in an arithmetic expansion +results in an invalid expression. + +@item +Non-interactive shells exit if there is a syntax error in a script read +with the @code{.} or @code{source} builtins, or in a string processed by +the @code{eval} builtin. + +@item +Redirection operators do not perform filename expansion on the word +in the redirection unless the shell is interactive. + +@item +Redirection operators do not perform word splitting on the word in the +redirection. + +@item +Function names must be valid shell @code{name}s. That is, they may not +contain characters other than letters, digits, and underscores, and +may not start with a digit. Declaring a function with an invalid name +causes a fatal syntax error in non-interactive shells. + +@item +Function names may not be the same as one of the @sc{posix} special +builtins. + +@item +@sc{posix} special builtins are found before shell functions +during command lookup. + +@item +The @code{time} reserved word may be used by itself as a command. When +used in this way, it displays timing statistics for the shell and its +completed children. The @env{TIMEFORMAT} variable controls the format +of the timing information. + +@item +When parsing and expanding a $@{@dots{}@} expansion that appears within +double quotes, single quotes are no longer special and cannot be used to +quote a closing brace or other special character, unless the operator is +one of those defined to perform pattern removal. In this case, they do +not have to appear as matched pairs. + +@item +The parser does not recognize @code{time} as a reserved word if the next +token begins with a @samp{-}. + +@item +If a @sc{posix} special builtin returns an error status, a +non-interactive shell exits. The fatal errors are those listed in +the @sc{posix} standard, and include things like passing incorrect options, +redirection errors, variable assignment errors for assignments preceding +the command name, and so on. + +@item +A non-interactive shell exits with an error status if a variable +assignment error occurs when no command name follows the assignment +statements. +A variable assignment error occurs, for example, when trying to assign +a value to a readonly variable. + +@item +A non-interactive shell exits with an error status if a variable +assignment error occurs in an assignment statement preceding a special +builtin, but not with any other simple command. + +@item +A non-interactive shell exits with an error status if the iteration +variable in a @code{for} statement or the selection variable in a +@code{select} statement is a readonly variable. + +@item +Process substitution is not available. + +@item +While variable indirection is available, it may not be applied to the +@samp{#} and @samp{?} special parameters. + +@item +Assignment statements preceding @sc{posix} special builtins +persist in the shell environment after the builtin completes. + +@item +Assignment statements preceding shell function calls persist in the +shell environment after the function returns, as if a @sc{posix} +special builtin command had been executed. + +@item +The @code{export} and @code{readonly} builtin commands display their +output in the format required by @sc{posix}. + +@item +The @code{trap} builtin displays signal names without the leading +@code{SIG}. + +@item +The @code{trap} builtin doesn't check the first argument for a possible +signal specification and revert the signal handling to the original +disposition if it is, unless that argument consists solely of digits and +is a valid signal number. If users want to reset the handler for a given +signal to the original disposition, they should use @samp{-} as the +first argument. + +@item +The @code{.} and @code{source} builtins do not search the current directory +for the filename argument if it is not found by searching @env{PATH}. + +@item +Subshells spawned to execute command substitutions inherit the value of +the @option{-e} option from the parent shell. When not in @sc{posix} mode, +Bash clears the @option{-e} option in such subshells. + +@item +Alias expansion is always enabled, even in non-interactive shells. + +@item +When the @code{alias} builtin displays alias definitions, it does not +display them with a leading @samp{alias } unless the @option{-p} option +is supplied. + +@item +When the @code{set} builtin is invoked without options, it does not display +shell function names and definitions. + +@item +When the @code{set} builtin is invoked without options, it displays +variable values without quotes, unless they contain shell metacharacters, +even if the result contains nonprinting characters. + +@item +When the @code{cd} builtin is invoked in @var{logical} mode, and the pathname +constructed from @code{$PWD} and the directory name supplied as an argument +does not refer to an existing directory, @code{cd} will fail instead of +falling back to @var{physical} mode. + +@item +The @code{pwd} builtin verifies that the value it prints is the same as the +current directory, even if it is not asked to check the file system with the +@option{-P} option. + +@item +When listing the history, the @code{fc} builtin does not include an +indication of whether or not a history entry has been modified. + +@item +The default editor used by @code{fc} is @code{ed}. + +@item +The @code{type} and @code{command} builtins will not report a non-executable +file as having been found, though the shell will attempt to execute such a +file if it is the only so-named file found in @code{$PATH}. + +@item +The @code{vi} editing mode will invoke the @code{vi} editor directly when +the @samp{v} command is run, instead of checking @code{$VISUAL} and +@code{$EDITOR}. + +@item +When the @code{xpg_echo} option is enabled, Bash does not attempt to interpret +any arguments to @code{echo} as options. Each argument is displayed, after +escape characters are converted. + +@item +The @code{ulimit} builtin uses a block size of 512 bytes for the @option{-c} +and @option{-f} options. + +@item +The arrival of @code{SIGCHLD} when a trap is set on @code{SIGCHLD} does +not interrupt the @code{wait} builtin and cause it to return immediately. +The trap command is run once for each child that exits. + +@item +The @code{read} builtin may be interrupted by a signal for which a trap +has been set. +If Bash receives a trapped signal while executing @code{read}, the trap +handler executes and @code{read} returns an exit status greater than 128. + +@end enumerate + +There is other @sc{posix} behavior that Bash does not implement by +default even when in @sc{posix} mode. +Specifically: + +@enumerate + +@item +The @code{fc} builtin checks @code{$EDITOR} as a program to edit history +entries if @code{FCEDIT} is unset, rather than defaulting directly to +@code{ed}. @code{fc} uses @code{ed} if @code{EDITOR} is unset. + +@item +As noted above, Bash requires the @code{xpg_echo} option to be enabled for +the @code{echo} builtin to be fully conformant. + +@end enumerate + +Bash can be configured to be @sc{posix}-conformant by default, by specifying +the @option{--enable-strict-posix-default} to @code{configure} when building +(@pxref{Optional Features}). + +@node Job Control +@chapter Job Control + +This chapter discusses what job control is, how it works, and how +Bash allows you to access its facilities. + +@menu +* Job Control Basics:: How job control works. +* Job Control Builtins:: Bash builtin commands used to interact + with job control. +* Job Control Variables:: Variables Bash uses to customize job + control. +@end menu + +@node Job Control Basics +@section Job Control Basics +@cindex job control +@cindex foreground +@cindex background +@cindex suspending jobs + +Job control +refers to the ability to selectively stop (suspend) +the execution of processes and continue (resume) +their execution at a later point. A user typically employs +this facility via an interactive interface supplied jointly +by the operating system kernel's terminal driver and Bash. + +The shell associates a @var{job} with each pipeline. It keeps a +table of currently executing jobs, which may be listed with the +@code{jobs} command. When Bash starts a job +asynchronously, it prints a line that looks +like: +@example +[1] 25647 +@end example +@noindent +indicating that this job is job number 1 and that the process @sc{id} +of the last process in the pipeline associated with this job is +25647. All of the processes in a single pipeline are members of +the same job. Bash uses the @var{job} abstraction as the +basis for job control. + +To facilitate the implementation of the user interface to job +control, the operating system maintains the notion of a current terminal +process group @sc{id}. Members of this process group (processes whose +process group @sc{id} is equal to the current terminal process group +@sc{id}) receive keyboard-generated signals such as @code{SIGINT}. +These processes are said to be in the foreground. Background +processes are those whose process group @sc{id} differs from the +terminal's; such processes are immune to keyboard-generated +signals. Only foreground processes are allowed to read from or, if +the user so specifies with @code{stty tostop}, write to the terminal. +Background processes which attempt to +read from (write to when @code{stty tostop} is in effect) the +terminal are sent a @code{SIGTTIN} (@code{SIGTTOU}) +signal by the kernel's terminal driver, +which, unless caught, suspends the process. + +If the operating system on which Bash is running supports +job control, Bash contains facilities to use it. Typing the +@var{suspend} character (typically @samp{^Z}, Control-Z) while a +process is running causes that process to be stopped and returns +control to Bash. Typing the @var{delayed suspend} character +(typically @samp{^Y}, Control-Y) causes the process to be stopped +when it attempts to read input from the terminal, and control to +be returned to Bash. The user then manipulates the state of +this job, using the @code{bg} command to continue it in the +background, the @code{fg} command to continue it in the +foreground, or the @code{kill} command to kill it. A @samp{^Z} +takes effect immediately, and has the additional side effect of +causing pending output and typeahead to be discarded. + +There are a number of ways to refer to a job in the shell. The +character @samp{%} introduces a job specification (@var{jobspec}). + +Job number @code{n} may be referred to as @samp{%n}. +The symbols @samp{%%} and @samp{%+} refer to the shell's notion of the +current job, which is the last job stopped while it was in the foreground +or started in the background. +A single @samp{%} (with no accompanying job specification) also refers +to the current job. +The previous job may be referenced using @samp{%-}. +If there is only a single job, @samp{%+} and @samp{%-} can both be used +to refer to that job. +In output pertaining to jobs (e.g., the output of the @code{jobs} +command), the current job is always flagged with a @samp{+}, and the +previous job with a @samp{-}. + +A job may also be referred to +using a prefix of the name used to start it, or using a substring +that appears in its command line. For example, @samp{%ce} refers +to a stopped @code{ce} job. Using @samp{%?ce}, on the +other hand, refers to any job containing the string @samp{ce} in +its command line. If the prefix or substring matches more than one job, +Bash reports an error. + +Simply naming a job can be used to bring it into the foreground: +@samp{%1} is a synonym for @samp{fg %1}, bringing job 1 from the +background into the foreground. Similarly, @samp{%1 &} resumes +job 1 in the background, equivalent to @samp{bg %1} + +The shell learns immediately whenever a job changes state. +Normally, Bash waits until it is about to print a prompt +before reporting changes in a job's status so as to not interrupt +any other output. +If the @option{-b} option to the @code{set} builtin is enabled, +Bash reports such changes immediately (@pxref{The Set Builtin}). +Any trap on @code{SIGCHLD} is executed for each child process +that exits. + +If an attempt to exit Bash is made while jobs are stopped, (or running, if +the @code{checkjobs} option is enabled -- see @ref{The Shopt Builtin}), the +shell prints a warning message, and if the @code{checkjobs} option is +enabled, lists the jobs and their statuses. +The @code{jobs} command may then be used to inspect their status. +If a second attempt to exit is made without an intervening command, +Bash does not print another warning, and any stopped jobs are terminated. + +@node Job Control Builtins +@section Job Control Builtins + +@table @code + +@item bg +@btindex bg +@example +bg [@var{jobspec} @dots{}] +@end example + +Resume each suspended job @var{jobspec} in the background, as if it +had been started with @samp{&}. +If @var{jobspec} is not supplied, the current job is used. +The return status is zero unless it is run when job control is not +enabled, or, when run with job control enabled, any +@var{jobspec} was not found or specifies a job +that was started without job control. + +@item fg +@btindex fg +@example +fg [@var{jobspec}] +@end example + +Resume the job @var{jobspec} in the foreground and make it the current job. +If @var{jobspec} is not supplied, the current job is used. +The return status is that of the command placed into the foreground, +or non-zero if run when job control is disabled or, when run with +job control enabled, @var{jobspec} does not specify a valid job or +@var{jobspec} specifies a job that was started without job control. + +@item jobs +@btindex jobs +@example +jobs [-lnprs] [@var{jobspec}] +jobs -x @var{command} [@var{arguments}] +@end example + +The first form lists the active jobs. The options have the +following meanings: + +@table @code +@item -l +List process @sc{id}s in addition to the normal information. + +@item -n +Display information only about jobs that have changed status since +the user was last notified of their status. + +@item -p +List only the process @sc{id} of the job's process group leader. + +@item -r +Display only running jobs. + +@item -s +Display only stopped jobs. +@end table + +If @var{jobspec} is given, +output is restricted to information about that job. +If @var{jobspec} is not supplied, the status of all jobs is +listed. + +If the @option{-x} option is supplied, @code{jobs} replaces any +@var{jobspec} found in @var{command} or @var{arguments} with the +corresponding process group @sc{id}, and executes @var{command}, +passing it @var{argument}s, returning its exit status. + +@item kill +@btindex kill +@example +kill [-s @var{sigspec}] [-n @var{signum}] [-@var{sigspec}] @var{jobspec} or @var{pid} +kill -l [@var{exit_status}] +@end example + +Send a signal specified by @var{sigspec} or @var{signum} to the process +named by job specification @var{jobspec} or process @sc{id} @var{pid}. +@var{sigspec} is either a case-insensitive signal name such as +@code{SIGINT} (with or without the @code{SIG} prefix) +or a signal number; @var{signum} is a signal number. +If @var{sigspec} and @var{signum} are not present, @code{SIGTERM} is used. +The @option{-l} option lists the signal names. +If any arguments are supplied when @option{-l} is given, the names of the +signals corresponding to the arguments are listed, and the return status +is zero. +@var{exit_status} is a number specifying a signal number or the exit +status of a process terminated by a signal. +The return status is zero if at least one signal was successfully sent, +or non-zero if an error occurs or an invalid option is encountered. + +@item wait +@btindex wait +@example +wait [-n] [@var{jobspec} or @var{pid} @dots{}] +@end example + +Wait until the child process specified by each process @sc{id} @var{pid} +or job specification @var{jobspec} exits and return the exit status of the +last command waited for. +If a job spec is given, all processes in the job are waited for. +If no arguments are given, all currently active child processes are +waited for, and the return status is zero. +If the @option{-n} option is supplied, @code{wait} waits for any job to +terminate and returns its exit status. +If neither @var{jobspec} nor @var{pid} specifies an active child process +of the shell, the return status is 127. + +@item disown +@btindex disown +@example +disown [-ar] [-h] [@var{jobspec} @dots{}] +@end example + +Without options, remove each @var{jobspec} from the table of +active jobs. +If the @option{-h} option is given, the job is not removed from the table, +but is marked so that @code{SIGHUP} is not sent to the job if the shell +receives a @code{SIGHUP}. +If @var{jobspec} is not present, and neither the @option{-a} nor the +@option{-r} option is supplied, the current job is used. +If no @var{jobspec} is supplied, the @option{-a} option means to remove or +mark all jobs; the @option{-r} option without a @var{jobspec} +argument restricts operation to running jobs. + +@item suspend +@btindex suspend +@example +suspend [-f] +@end example + +Suspend the execution of this shell until it receives a +@code{SIGCONT} signal. +A login shell cannot be suspended; the @option{-f} +option can be used to override this and force the suspension. +@end table + +When job control is not active, the @code{kill} and @code{wait} +builtins do not accept @var{jobspec} arguments. They must be +supplied process @sc{id}s. + +@node Job Control Variables +@section Job Control Variables + +@vtable @code + +@item auto_resume +This variable controls how the shell interacts with the user and +job control. If this variable exists then single word simple +commands without redirections are treated as candidates for resumption +of an existing job. There is no ambiguity allowed; if there is +more than one job beginning with the string typed, then +the most recently accessed job will be selected. +The name of a stopped job, in this context, is the command line +used to start it. If this variable is set to the value @samp{exact}, +the string supplied must match the name of a stopped job exactly; +if set to @samp{substring}, +the string supplied needs to match a substring of the name of a +stopped job. The @samp{substring} value provides functionality +analogous to the @samp{%?} job @sc{id} (@pxref{Job Control Basics}). +If set to any other value, the supplied string must +be a prefix of a stopped job's name; this provides functionality +analogous to the @samp{%} job @sc{id}. + +@end vtable + +@set readline-appendix +@set history-appendix +@cindex Readline, how to use +@include rluser.texi +@cindex History, how to use +@include hsuser.texi +@clear readline-appendix +@clear history-appendix + +@node Installing Bash +@chapter Installing Bash + +This chapter provides basic instructions for installing Bash on +the various supported platforms. The distribution supports the +@sc{gnu} operating systems, nearly every version of Unix, and several +non-Unix systems such as BeOS and Interix. +Other independent ports exist for +@sc{ms-dos}, @sc{os/2}, and Windows platforms. + +@menu +* Basic Installation:: Installation instructions. +* Compilers and Options:: How to set special options for various + systems. +* Compiling For Multiple Architectures:: How to compile Bash for more + than one kind of system from + the same source tree. +* Installation Names:: How to set the various paths used by the installation. +* Specifying the System Type:: How to configure Bash for a particular system. +* Sharing Defaults:: How to share default configuration values among GNU + programs. +* Operation Controls:: Options recognized by the configuration program. +* Optional Features:: How to enable and disable optional features when + building Bash. +@end menu + +@node Basic Installation +@section Basic Installation +@cindex installation +@cindex configuration +@cindex Bash installation +@cindex Bash configuration + +These are installation instructions for Bash. + +The simplest way to compile Bash is: + +@enumerate +@item +@code{cd} to the directory containing the source code and type +@samp{./configure} to configure Bash for your system. If you're +using @code{csh} on an old version of System V, you might need to +type @samp{sh ./configure} instead to prevent @code{csh} from trying +to execute @code{configure} itself. + +Running @code{configure} takes some time. +While running, it prints messages telling which features it is +checking for. + +@item +Type @samp{make} to compile Bash and build the @code{bashbug} bug +reporting script. + +@item +Optionally, type @samp{make tests} to run the Bash test suite. + +@item +Type @samp{make install} to install @code{bash} and @code{bashbug}. +This will also install the manual pages and Info file. + +@end enumerate + +The @code{configure} shell script attempts to guess correct +values for various system-dependent variables used during +compilation. It uses those values to create a @file{Makefile} in +each directory of the package (the top directory, the +@file{builtins}, @file{doc}, and @file{support} directories, +each directory under @file{lib}, and several others). It also creates a +@file{config.h} file containing system-dependent definitions. +Finally, it creates a shell script named @code{config.status} that you +can run in the future to recreate the current configuration, a +file @file{config.cache} that saves the results of its tests to +speed up reconfiguring, and a file @file{config.log} containing +compiler output (useful mainly for debugging @code{configure}). +If at some point +@file{config.cache} contains results you don't want to keep, you +may remove or edit it. + +To find out more about the options and arguments that the +@code{configure} script understands, type + +@example +bash-2.04$ ./configure --help +@end example + +@noindent +at the Bash prompt in your Bash source directory. + +If you need to do unusual things to compile Bash, please +try to figure out how @code{configure} could check whether or not +to do them, and mail diffs or instructions to +@email{bash-maintainers@@gnu.org} so they can be +considered for the next release. + +The file @file{configure.ac} is used to create @code{configure} +by a program called Autoconf. You only need +@file{configure.ac} if you want to change it or regenerate +@code{configure} using a newer version of Autoconf. If +you do this, make sure you are using Autoconf version 2.50 or +newer. + +You can remove the program binaries and object files from the +source code directory by typing @samp{make clean}. To also remove the +files that @code{configure} created (so you can compile Bash for +a different kind of computer), type @samp{make distclean}. + +@node Compilers and Options +@section Compilers and Options + +Some systems require unusual options for compilation or linking +that the @code{configure} script does not know about. You can +give @code{configure} initial values for variables by setting +them in the environment. Using a Bourne-compatible shell, you +can do that on the command line like this: + +@example +CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure +@end example + +On systems that have the @code{env} program, you can do it like this: + +@example +env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure +@end example + +The configuration process uses GCC to build Bash if it +is available. + +@node Compiling For Multiple Architectures +@section Compiling For Multiple Architectures + +You can compile Bash for more than one kind of computer at the +same time, by placing the object files for each architecture in their +own directory. To do this, you must use a version of @code{make} that +supports the @code{VPATH} variable, such as GNU @code{make}. +@code{cd} to the +directory where you want the object files and executables to go and run +the @code{configure} script from the source directory. You may need to +supply the @option{--srcdir=PATH} argument to tell @code{configure} where the +source files are. @code{configure} automatically checks for the +source code in the directory that @code{configure} is in and in `..'. + +If you have to use a @code{make} that does not supports the @code{VPATH} +variable, you can compile Bash for one architecture at a +time in the source code directory. After you have installed +Bash for one architecture, use @samp{make distclean} before +reconfiguring for another architecture. + +Alternatively, if your system supports symbolic links, you can use the +@file{support/mkclone} script to create a build tree which has +symbolic links back to each file in the source directory. Here's an +example that creates a build directory in the current directory from a +source directory @file{/usr/gnu/src/bash-2.0}: + +@example +bash /usr/gnu/src/bash-2.0/support/mkclone -s /usr/gnu/src/bash-2.0 . +@end example + +@noindent +The @code{mkclone} script requires Bash, so you must have already built +Bash for at least one architecture before you can create build +directories for other architectures. + +@node Installation Names +@section Installation Names + +By default, @samp{make install} will install into +@file{/usr/local/bin}, @file{/usr/local/man}, etc. You can +specify an installation prefix other than @file{/usr/local} by +giving @code{configure} the option @option{--prefix=@var{PATH}}, +or by specifying a value for the @code{DESTDIR} @samp{make} +variable when running @samp{make install}. + +You can specify separate installation prefixes for +architecture-specific files and architecture-independent files. +If you give @code{configure} the option +@option{--exec-prefix=@var{PATH}}, @samp{make install} will use +@var{PATH} as the prefix for installing programs and libraries. +Documentation and other data files will still use the regular prefix. + +@node Specifying the System Type +@section Specifying the System Type + +There may be some features @code{configure} can not figure out +automatically, but need to determine by the type of host Bash +will run on. Usually @code{configure} can figure that +out, but if it prints a message saying it can not guess the host +type, give it the @option{--host=TYPE} option. @samp{TYPE} can +either be a short name for the system type, such as @samp{sun4}, +or a canonical name with three fields: @samp{CPU-COMPANY-SYSTEM} +(e.g., @samp{i386-unknown-freebsd4.2}). + +See the file @file{support/config.sub} for the possible +values of each field. + +@node Sharing Defaults +@section Sharing Defaults + +If you want to set default values for @code{configure} scripts to +share, you can create a site shell script called +@code{config.site} that gives default values for variables like +@code{CC}, @code{cache_file}, and @code{prefix}. @code{configure} +looks for @file{PREFIX/share/config.site} if it exists, then +@file{PREFIX/etc/config.site} if it exists. Or, you can set the +@code{CONFIG_SITE} environment variable to the location of the site +script. A warning: the Bash @code{configure} looks for a site script, +but not all @code{configure} scripts do. + +@node Operation Controls +@section Operation Controls + +@code{configure} recognizes the following options to control how it +operates. + +@table @code + +@item --cache-file=@var{file} +Use and save the results of the tests in +@var{file} instead of @file{./config.cache}. Set @var{file} to +@file{/dev/null} to disable caching, for debugging +@code{configure}. + +@item --help +Print a summary of the options to @code{configure}, and exit. + +@item --quiet +@itemx --silent +@itemx -q +Do not print messages saying which checks are being made. + +@item --srcdir=@var{dir} +Look for the Bash source code in directory @var{dir}. Usually +@code{configure} can determine that directory automatically. + +@item --version +Print the version of Autoconf used to generate the @code{configure} +script, and exit. +@end table + +@code{configure} also accepts some other, not widely used, boilerplate +options. @samp{configure --help} prints the complete list. + +@node Optional Features +@section Optional Features + +The Bash @code{configure} has a number of @option{--enable-@var{feature}} +options, where @var{feature} indicates an optional part of Bash. +There are also several @option{--with-@var{package}} options, +where @var{package} is something like @samp{bash-malloc} or @samp{purify}. +To turn off the default use of a package, use +@option{--without-@var{package}}. To configure Bash without a feature +that is enabled by default, use @option{--disable-@var{feature}}. + +Here is a complete list of the @option{--enable-} and +@option{--with-} options that the Bash @code{configure} recognizes. + +@table @code +@item --with-afs +Define if you are using the Andrew File System from Transarc. + +@item --with-bash-malloc +Use the Bash version of +@code{malloc} in the directory @file{lib/malloc}. This is not the same +@code{malloc} that appears in @sc{gnu} libc, but an older version +originally derived from the 4.2 @sc{bsd} @code{malloc}. This @code{malloc} +is very fast, but wastes some space on each allocation. +This option is enabled by default. +The @file{NOTES} file contains a list of systems for +which this should be turned off, and @code{configure} disables this +option automatically for a number of systems. + +@item --with-curses +Use the curses library instead of the termcap library. This should +be supplied if your system has an inadequate or incomplete termcap +database. + +@item --with-gnu-malloc +A synonym for @code{--with-bash-malloc}. + +@item --with-installed-readline[=@var{PREFIX}] +Define this to make Bash link with a locally-installed version of Readline +rather than the version in @file{lib/readline}. This works only with +Readline 5.0 and later versions. If @var{PREFIX} is @code{yes} or not +supplied, @code{configure} uses the values of the make variables +@code{includedir} and @code{libdir}, which are subdirectories of @code{prefix} +by default, to find the installed version of Readline if it is not in +the standard system include and library directories. +If @var{PREFIX} is @code{no}, Bash links with the version in +@file{lib/readline}. +If @var{PREFIX} is set to any other value, @code{configure} treats it as +a directory pathname and looks for +the installed version of Readline in subdirectories of that directory +(include files in @var{PREFIX}/@code{include} and the library in +@var{PREFIX}/@code{lib}). + +@item --with-purify +Define this to use the Purify memory allocation checker from Rational +Software. + +@item --enable-minimal-config +This produces a shell with minimal features, close to the historical +Bourne shell. +@end table + +There are several @option{--enable-} options that alter how Bash is +compiled and linked, rather than changing run-time features. + +@table @code +@item --enable-largefile +Enable support for @uref{http://www.sas.com/standards/large_file/x_open.20Mar96.html, +large files} if the operating system requires special compiler options +to build programs which can access large files. This is enabled by +default, if the operating system provides large file support. + +@item --enable-profiling +This builds a Bash binary that produces profiling information to be +processed by @code{gprof} each time it is executed. + +@item --enable-static-link +This causes Bash to be linked statically, if @code{gcc} is being used. +This could be used to build a version to use as root's shell. +@end table + +The @samp{minimal-config} option can be used to disable all of +the following options, but it is processed first, so individual +options may be enabled using @samp{enable-@var{feature}}. + +All of the following options except for @samp{disabled-builtins}, +@samp{direxpand-default}, and +@samp{xpg-echo-default} are +enabled by default, unless the operating system does not provide the +necessary support. + +@table @code +@item --enable-alias +Allow alias expansion and include the @code{alias} and @code{unalias} +builtins (@pxref{Aliases}). + +@item --enable-arith-for-command +Include support for the alternate form of the @code{for} command +that behaves like the C language @code{for} statement +(@pxref{Looping Constructs}). + +@item --enable-array-variables +Include support for one-dimensional array shell variables +(@pxref{Arrays}). + +@item --enable-bang-history +Include support for @code{csh}-like history substitution +(@pxref{History Interaction}). + +@item --enable-brace-expansion +Include @code{csh}-like brace expansion +( @code{b@{a,b@}c} @expansion{} @code{bac bbc} ). +See @ref{Brace Expansion}, for a complete description. + +@item --enable-casemod-attributes +Include support for case-modifying attributes in the @code{declare} builtin +and assignment statements. Variables with the @var{uppercase} attribute, +for example, will have their values converted to uppercase upon assignment. + +@item --enable-casemod-expansion +Include support for case-modifying word expansions. + +@item --enable-command-timing +Include support for recognizing @code{time} as a reserved word and for +displaying timing statistics for the pipeline following @code{time} +(@pxref{Pipelines}). +This allows pipelines as well as shell builtins and functions to be timed. + +@item --enable-cond-command +Include support for the @code{[[} conditional command. +(@pxref{Conditional Constructs}). + +@item --enable-cond-regexp +Include support for matching @sc{posix} regular expressions using the +@samp{=~} binary operator in the @code{[[} conditional command. +(@pxref{Conditional Constructs}). + +@item --enable-coprocesses +Include support for coprocesses and the @code{coproc} reserved word +(@pxref{Pipelines}). + +@item --enable-debugger +Include support for the bash debugger (distributed separately). + +@item --enable-direxpand-default +Cause the @code{direxpand} shell option (@pxref{The Shopt Builtin}) +to be enabled by default when the shell starts. +It is normally disabled by default. + +@item --enable-directory-stack +Include support for a @code{csh}-like directory stack and the +@code{pushd}, @code{popd}, and @code{dirs} builtins +(@pxref{The Directory Stack}). + +@item --enable-disabled-builtins +Allow builtin commands to be invoked via @samp{builtin xxx} +even after @code{xxx} has been disabled using @samp{enable -n xxx}. +See @ref{Bash Builtins}, for details of the @code{builtin} and +@code{enable} builtin commands. + +@item --enable-dparen-arithmetic +Include support for the @code{((@dots{}))} command +(@pxref{Conditional Constructs}). + +@item --enable-extended-glob +Include support for the extended pattern matching features described +above under @ref{Pattern Matching}. + +@item --enable-extended-glob-default +Set the default value of the @var{extglob} shell option described +above under @ref{The Shopt Builtin} to be enabled. + +@item --enable-glob-asciirange-default +Set the default value of the @var{globasciiranges} shell option described +above under @ref{The Shopt Builtin} to be enabled. +This controls the behavior of character ranges when used in pattern matching +bracket expressions. + +@item --enable-help-builtin +Include the @code{help} builtin, which displays help on shell builtins and +variables (@pxref{Bash Builtins}). + +@item --enable-history +Include command history and the @code{fc} and @code{history} +builtin commands (@pxref{Bash History Facilities}). + +@item --enable-job-control +This enables the job control features (@pxref{Job Control}), +if the operating system supports them. + +@item --enable-multibyte +This enables support for multibyte characters if the operating +system provides the necessary support. + +@item --enable-net-redirections +This enables the special handling of filenames of the form +@code{/dev/tcp/@var{host}/@var{port}} and +@code{/dev/udp/@var{host}/@var{port}} +when used in redirections (@pxref{Redirections}). + +@item --enable-process-substitution +This enables process substitution (@pxref{Process Substitution}) if +the operating system provides the necessary support. + +@item --enable-progcomp +Enable the programmable completion facilities +(@pxref{Programmable Completion}). +If Readline is not enabled, this option has no effect. + +@item --enable-prompt-string-decoding +Turn on the interpretation of a number of backslash-escaped characters +in the @env{$PS1}, @env{$PS2}, @env{$PS3}, and @env{$PS4} prompt +strings. See @ref{Controlling the Prompt}, for a complete list of prompt +string escape sequences. + +@item --enable-readline +Include support for command-line editing and history with the Bash +version of the Readline library (@pxref{Command Line Editing}). + +@item --enable-restricted +Include support for a @dfn{restricted shell}. If this is enabled, Bash, +when called as @code{rbash}, enters a restricted mode. See +@ref{The Restricted Shell}, for a description of restricted mode. + +@item --enable-select +Include the @code{select} compound command, which allows the generation of +simple menus (@pxref{Conditional Constructs}). + +@item --enable-separate-helpfiles +Use external files for the documentation displayed by the @code{help} builtin +instead of storing the text internally. + +@item --enable-single-help-strings +Store the text displayed by the @code{help} builtin as a single string for +each help topic. This aids in translating the text to different languages. +You may need to disable this if your compiler cannot handle very long string +literals. + +@item --enable-strict-posix-default +Make Bash @sc{posix}-conformant by default (@pxref{Bash POSIX Mode}). + +@item --enable-usg-echo-default +A synonym for @code{--enable-xpg-echo-default}. + +@item --enable-xpg-echo-default +Make the @code{echo} builtin expand backslash-escaped characters by default, +without requiring the @option{-e} option. +This sets the default value of the @code{xpg_echo} shell option to @code{on}, +which makes the Bash @code{echo} behave more like the version specified in +the Single Unix Specification, version 3. +@xref{Bash Builtins}, for a description of the escape sequences that +@code{echo} recognizes. +@end table + +The file @file{config-top.h} contains C Preprocessor +@samp{#define} statements for options which are not settable from +@code{configure}. +Some of these are not meant to be changed; beware of the consequences if +you do. +Read the comments associated with each definition for more +information about its effect. + +@node Reporting Bugs +@appendix Reporting Bugs + +Please report all bugs you find in Bash. +But first, you should +make sure that it really is a bug, and that it appears in the latest +version of Bash. +The latest version of Bash is always available for FTP from +@uref{ftp://ftp.gnu.org/pub/gnu/bash/}. + +Once you have determined that a bug actually exists, use the +@code{bashbug} command to submit a bug report. +If you have a fix, you are encouraged to mail that as well! +Suggestions and `philosophical' bug reports may be mailed +to @email{bug-bash@@gnu.org} or posted to the Usenet +newsgroup @code{gnu.bash.bug}. + +All bug reports should include: +@itemize @bullet +@item +The version number of Bash. +@item +The hardware and operating system. +@item +The compiler used to compile Bash. +@item +A description of the bug behaviour. +@item +A short script or `recipe' which exercises the bug and may be used +to reproduce it. +@end itemize + +@noindent +@code{bashbug} inserts the first three items automatically into +the template it provides for filing a bug report. + +Please send all reports concerning this manual to +@email{bug-bash@@gnu.org}. + +@node Major Differences From The Bourne Shell +@appendix Major Differences From The Bourne Shell + +Bash implements essentially the same grammar, parameter and +variable expansion, redirection, and quoting as the Bourne Shell. +Bash uses the @sc{posix} standard as the specification of +how these features are to be implemented. There are some +differences between the traditional Bourne shell and Bash; this +section quickly details the differences of significance. A +number of these differences are explained in greater depth in +previous sections. +This section uses the version of @code{sh} included in SVR4.2 (the +last version of the historical Bourne shell) as the baseline reference. + +@itemize @bullet + +@item +Bash is @sc{posix}-conformant, even where the @sc{posix} specification +differs from traditional @code{sh} behavior (@pxref{Bash POSIX Mode}). + +@item +Bash has multi-character invocation options (@pxref{Invoking Bash}). + +@item +Bash has command-line editing (@pxref{Command Line Editing}) and +the @code{bind} builtin. + +@item +Bash provides a programmable word completion mechanism +(@pxref{Programmable Completion}), and builtin commands +@code{complete}, @code{compgen}, and @code{compopt}, to +manipulate it. + +@item +Bash has command history (@pxref{Bash History Facilities}) and the +@code{history} and @code{fc} builtins to manipulate it. +The Bash history list maintains timestamp information and uses the +value of the @code{HISTTIMEFORMAT} variable to display it. + +@item +Bash implements @code{csh}-like history expansion +(@pxref{History Interaction}). + +@item +Bash has one-dimensional array variables (@pxref{Arrays}), and the +appropriate variable expansions and assignment syntax to use them. +Several of the Bash builtins take options to act on arrays. +Bash provides a number of built-in array variables. + +@item +The @code{$'@dots{}'} quoting syntax, which expands ANSI-C +backslash-escaped characters in the text between the single quotes, +is supported (@pxref{ANSI-C Quoting}). + +@item +Bash supports the @code{$"@dots{}"} quoting syntax to do +locale-specific translation of the characters between the double +quotes. The @option{-D}, @option{--dump-strings}, and @option{--dump-po-strings} +invocation options list the translatable strings found in a script +(@pxref{Locale Translation}). + +@item +Bash implements the @code{!} keyword to negate the return value of +a pipeline (@pxref{Pipelines}). +Very useful when an @code{if} statement needs to act only if a test fails. +The Bash @samp{-o pipefail} option to @code{set} will cause a pipeline to +return a failure status if any command fails. + +@item +Bash has the @code{time} reserved word and command timing (@pxref{Pipelines}). +The display of the timing statistics may be controlled with the +@env{TIMEFORMAT} variable. + +@item +Bash implements the @code{for (( @var{expr1} ; @var{expr2} ; @var{expr3} ))} +arithmetic for command, similar to the C language (@pxref{Looping Constructs}). + +@item +Bash includes the @code{select} compound command, which allows the +generation of simple menus (@pxref{Conditional Constructs}). + +@item +Bash includes the @code{[[} compound command, which makes conditional +testing part of the shell grammar (@pxref{Conditional Constructs}), including +optional regular expression matching. + +@item +Bash provides optional case-insensitive matching for the @code{case} and +@code{[[} constructs. + +@item +Bash includes brace expansion (@pxref{Brace Expansion}) and tilde +expansion (@pxref{Tilde Expansion}). + +@item +Bash implements command aliases and the @code{alias} and @code{unalias} +builtins (@pxref{Aliases}). + +@item +Bash provides shell arithmetic, the @code{((} compound command +(@pxref{Conditional Constructs}), +and arithmetic expansion (@pxref{Shell Arithmetic}). + +@item +Variables present in the shell's initial environment are automatically +exported to child processes. The Bourne shell does not normally do +this unless the variables are explicitly marked using the @code{export} +command. + +@item +Bash supports the @samp{+=} assignment operator, which appends to the value +of the variable named on the left hand side. + +@item +Bash includes the @sc{posix} pattern removal @samp{%}, @samp{#}, @samp{%%} +and @samp{##} expansions to remove leading or trailing substrings from +variable values (@pxref{Shell Parameter Expansion}). + +@item +The expansion @code{$@{#xx@}}, which returns the length of @code{$@{xx@}}, +is supported (@pxref{Shell Parameter Expansion}). + +@item +The expansion @code{$@{var:}@var{offset}@code{[:}@var{length}@code{]@}}, +which expands to the substring of @code{var}'s value of length +@var{length}, beginning at @var{offset}, is present +(@pxref{Shell Parameter Expansion}). + +@item +The expansion +@code{$@{var/[/]}@var{pattern}@code{[/}@var{replacement}@code{]@}}, +which matches @var{pattern} and replaces it with @var{replacement} in +the value of @code{var}, is available (@pxref{Shell Parameter Expansion}). + +@item +The expansion @code{$@{!@var{prefix}*@}} expansion, which expands to +the names of all shell variables whose names begin with @var{prefix}, +is available (@pxref{Shell Parameter Expansion}). + +@item +Bash has @var{indirect} variable expansion using @code{$@{!word@}} +(@pxref{Shell Parameter Expansion}). + +@item +Bash can expand positional parameters beyond @code{$9} using +@code{$@{@var{num}@}}. + +@item +The @sc{posix} @code{$()} form of command substitution +is implemented (@pxref{Command Substitution}), +and preferred to the Bourne shell's @code{``} (which +is also implemented for backwards compatibility). + +@item +Bash has process substitution (@pxref{Process Substitution}). + +@item +Bash automatically assigns variables that provide information about the +current user (@env{UID}, @env{EUID}, and @env{GROUPS}), the current host +(@env{HOSTTYPE}, @env{OSTYPE}, @env{MACHTYPE}, and @env{HOSTNAME}), +and the instance of Bash that is running (@env{BASH}, +@env{BASH_VERSION}, and @env{BASH_VERSINFO}). @xref{Bash Variables}, +for details. + +@item +The @env{IFS} variable is used to split only the results of expansion, +not all words (@pxref{Word Splitting}). +This closes a longstanding shell security hole. + +@item +The filename expansion bracket expression code uses @samp{!} and @samp{^} +to negate the set of characters between the brackets. +The Bourne shell uses only @samp{!}. + +@item +Bash implements the full set of @sc{posix} filename expansion operators, +including @var{character classes}, @var{equivalence classes}, and +@var{collating symbols} (@pxref{Filename Expansion}). + +@item +Bash implements extended pattern matching features when the @code{extglob} +shell option is enabled (@pxref{Pattern Matching}). + +@item +It is possible to have a variable and a function with the same name; +@code{sh} does not separate the two name spaces. + +@item +Bash functions are permitted to have local variables using the +@code{local} builtin, and thus useful recursive functions may be written +(@pxref{Bash Builtins}). + +@item +Variable assignments preceding commands affect only that command, even +builtins and functions (@pxref{Environment}). +In @code{sh}, all variable assignments +preceding commands are global unless the command is executed from the +file system. + +@item +Bash performs filename expansion on filenames specified as operands +to input and output redirection operators (@pxref{Redirections}). + +@item +Bash contains the @samp{<>} redirection operator, allowing a file to be +opened for both reading and writing, and the @samp{&>} redirection +operator, for directing standard output and standard error to the same +file (@pxref{Redirections}). + +@item +Bash includes the @samp{<<<} redirection operator, allowing a string to +be used as the standard input to a command. + +@item +Bash implements the @samp{[n]<&@var{word}} and @samp{[n]>&@var{word}} +redirection operators, which move one file descriptor to another. + +@item +Bash treats a number of filenames specially when they are +used in redirection operators (@pxref{Redirections}). + +@item +Bash can open network connections to arbitrary machines and services +with the redirection operators (@pxref{Redirections}). + +@item +The @code{noclobber} option is available to avoid overwriting existing +files with output redirection (@pxref{The Set Builtin}). +The @samp{>|} redirection operator may be used to override @code{noclobber}. + +@item +The Bash @code{cd} and @code{pwd} builtins (@pxref{Bourne Shell Builtins}) +each take @option{-L} and @option{-P} options to switch between logical and +physical modes. + +@item +Bash allows a function to override a builtin with the same name, and provides +access to that builtin's functionality within the function via the +@code{builtin} and @code{command} builtins (@pxref{Bash Builtins}). + +@item +The @code{command} builtin allows selective disabling of functions +when command lookup is performed (@pxref{Bash Builtins}). + +@item +Individual builtins may be enabled or disabled using the @code{enable} +builtin (@pxref{Bash Builtins}). + +@item +The Bash @code{exec} builtin takes additional options that allow users +to control the contents of the environment passed to the executed +command, and what the zeroth argument to the command is to be +(@pxref{Bourne Shell Builtins}). + +@item +Shell functions may be exported to children via the environment +using @code{export -f} (@pxref{Shell Functions}). + +@item +The Bash @code{export}, @code{readonly}, and @code{declare} builtins can +take a @option{-f} option to act on shell functions, a @option{-p} option to +display variables with various attributes set in a format that can be +used as shell input, a @option{-n} option to remove various variable +attributes, and @samp{name=value} arguments to set variable attributes +and values simultaneously. + +@item +The Bash @code{hash} builtin allows a name to be associated with +an arbitrary filename, even when that filename cannot be found by +searching the @env{$PATH}, using @samp{hash -p} +(@pxref{Bourne Shell Builtins}). + +@item +Bash includes a @code{help} builtin for quick reference to shell +facilities (@pxref{Bash Builtins}). + +@item +The @code{printf} builtin is available to display formatted output +(@pxref{Bash Builtins}). + +@item +The Bash @code{read} builtin (@pxref{Bash Builtins}) +will read a line ending in @samp{\} with +the @option{-r} option, and will use the @env{REPLY} variable as a +default if no non-option arguments are supplied. +The Bash @code{read} builtin +also accepts a prompt string with the @option{-p} option and will use +Readline to obtain the line when given the @option{-e} option. +The @code{read} builtin also has additional options to control input: +the @option{-s} option will turn off echoing of input characters as +they are read, the @option{-t} option will allow @code{read} to time out +if input does not arrive within a specified number of seconds, the +@option{-n} option will allow reading only a specified number of +characters rather than a full line, and the @option{-d} option will read +until a particular character rather than newline. + +@item +The @code{return} builtin may be used to abort execution of scripts +executed with the @code{.} or @code{source} builtins +(@pxref{Bourne Shell Builtins}). + +@item +Bash includes the @code{shopt} builtin, for finer control of shell +optional capabilities (@pxref{The Shopt Builtin}), and allows these options +to be set and unset at shell invocation (@pxref{Invoking Bash}). + +@item +Bash has much more optional behavior controllable with the @code{set} +builtin (@pxref{The Set Builtin}). + +@item +The @samp{-x} (@option{xtrace}) option displays commands other than +simple commands when performing an execution trace +(@pxref{The Set Builtin}). + +@item +The @code{test} builtin (@pxref{Bourne Shell Builtins}) +is slightly different, as it implements the @sc{posix} algorithm, +which specifies the behavior based on the number of arguments. + +@item +Bash includes the @code{caller} builtin, which displays the context of +any active subroutine call (a shell function or a script executed with +the @code{.} or @code{source} builtins). This supports the bash +debugger. + +@item +The @code{trap} builtin (@pxref{Bourne Shell Builtins}) allows a +@code{DEBUG} pseudo-signal specification, similar to @code{EXIT}. +Commands specified with a @code{DEBUG} trap are executed before every +simple command, @code{for} command, @code{case} command, +@code{select} command, every arithmetic @code{for} command, and before +the first command executes in a shell function. +The @code{DEBUG} trap is not inherited by shell functions unless the +function has been given the @code{trace} attribute or the +@code{functrace} option has been enabled using the @code{shopt} builtin. +The @code{extdebug} shell option has additional effects on the +@code{DEBUG} trap. + +The @code{trap} builtin (@pxref{Bourne Shell Builtins}) allows an +@code{ERR} pseudo-signal specification, similar to @code{EXIT} and @code{DEBUG}. +Commands specified with an @code{ERR} trap are executed after a simple +command fails, with a few exceptions. +The @code{ERR} trap is not inherited by shell functions unless the +@code{-o errtrace} option to the @code{set} builtin is enabled. + +The @code{trap} builtin (@pxref{Bourne Shell Builtins}) allows a +@code{RETURN} pseudo-signal specification, similar to +@code{EXIT} and @code{DEBUG}. +Commands specified with an @code{RETURN} trap are executed before +execution resumes after a shell function or a shell script executed with +@code{.} or @code{source} returns. +The @code{RETURN} trap is not inherited by shell functions unless the +function has been given the @code{trace} attribute or the +@code{functrace} option has been enabled using the @code{shopt} builtin. + +@item +The Bash @code{type} builtin is more extensive and gives more information +about the names it finds (@pxref{Bash Builtins}). + +@item +The Bash @code{umask} builtin permits a @option{-p} option to cause +the output to be displayed in the form of a @code{umask} command +that may be reused as input (@pxref{Bourne Shell Builtins}). + +@item +Bash implements a @code{csh}-like directory stack, and provides the +@code{pushd}, @code{popd}, and @code{dirs} builtins to manipulate it +(@pxref{The Directory Stack}). +Bash also makes the directory stack visible as the value of the +@env{DIRSTACK} shell variable. + +@item +Bash interprets special backslash-escaped characters in the prompt +strings when interactive (@pxref{Controlling the Prompt}). + +@item +The Bash restricted mode is more useful (@pxref{The Restricted Shell}); +the SVR4.2 shell restricted mode is too limited. + +@item +The @code{disown} builtin can remove a job from the internal shell +job table (@pxref{Job Control Builtins}) or suppress the sending +of @code{SIGHUP} to a job when the shell exits as the result of a +@code{SIGHUP}. + +@item +Bash includes a number of features to support a separate debugger for +shell scripts. + +@item +The SVR4.2 shell has two privilege-related builtins +(@code{mldmode} and @code{priv}) not present in Bash. + +@item +Bash does not have the @code{stop} or @code{newgrp} builtins. + +@item +Bash does not use the @env{SHACCT} variable or perform shell accounting. + +@item +The SVR4.2 @code{sh} uses a @env{TIMEOUT} variable like Bash uses +@env{TMOUT}. + +@end itemize + +@noindent +More features unique to Bash may be found in @ref{Bash Features}. + + +@appendixsec Implementation Differences From The SVR4.2 Shell + +Since Bash is a completely new implementation, it does not suffer from +many of the limitations of the SVR4.2 shell. For instance: + +@itemize @bullet + +@item +Bash does not fork a subshell when redirecting into or out of +a shell control structure such as an @code{if} or @code{while} +statement. + +@item +Bash does not allow unbalanced quotes. The SVR4.2 shell will silently +insert a needed closing quote at @code{EOF} under certain circumstances. +This can be the cause of some hard-to-find errors. + +@item +The SVR4.2 shell uses a baroque memory management scheme based on +trapping @code{SIGSEGV}. If the shell is started from a process with +@code{SIGSEGV} blocked (e.g., by using the @code{system()} C library +function call), it misbehaves badly. + +@item +In a questionable attempt at security, the SVR4.2 shell, +when invoked without the @option{-p} option, will alter its real +and effective @sc{uid} and @sc{gid} if they are less than some +magic threshold value, commonly 100. +This can lead to unexpected results. + +@item +The SVR4.2 shell does not allow users to trap @code{SIGSEGV}, +@code{SIGALRM}, or @code{SIGCHLD}. + +@item +The SVR4.2 shell does not allow the @env{IFS}, @env{MAILCHECK}, +@env{PATH}, @env{PS1}, or @env{PS2} variables to be unset. + +@item +The SVR4.2 shell treats @samp{^} as the undocumented equivalent of +@samp{|}. + +@item +Bash allows multiple option arguments when it is invoked (@code{-x -v}); +the SVR4.2 shell allows only one option argument (@code{-xv}). In +fact, some versions of the shell dump core if the second argument begins +with a @samp{-}. + +@item +The SVR4.2 shell exits a script if any builtin fails; Bash exits +a script only if one of the @sc{posix} special builtins fails, and +only for certain failures, as enumerated in the @sc{posix} standard. + +@item +The SVR4.2 shell behaves differently when invoked as @code{jsh} +(it turns on job control). +@end itemize + +@node GNU Free Documentation License +@appendix GNU Free Documentation License + +@include fdl.texi + +@node Indexes +@appendix Indexes + +@menu +* Builtin Index:: Index of Bash builtin commands. +* Reserved Word Index:: Index of Bash reserved words. +* Variable Index:: Quick reference helps you find the + variable you want. +* Function Index:: Index of bindable Readline functions. +* Concept Index:: General index for concepts described in + this manual. +@end menu + +@node Builtin Index +@appendixsec Index of Shell Builtin Commands +@printindex bt + +@node Reserved Word Index +@appendixsec Index of Shell Reserved Words +@printindex rw + +@node Variable Index +@appendixsec Parameter and Variable Index +@printindex vr + +@node Function Index +@appendixsec Function Index +@printindex fn + +@node Concept Index +@appendixsec Concept Index +@printindex cp + +@bye diff --git a/doc/version.texi b/doc/version.texi index ccd67cb0c..08183da3f 100644 --- a/doc/version.texi +++ b/doc/version.texi @@ -7,5 +7,5 @@ Copyright (C) 1988-2014 Free Software Foundation, Inc. @set EDITION 4.3 @set VERSION 4.3 -@set UPDATED 27 August 2014 -@set UPDATED-MONTH August 2014 +@set UPDATED 6 September 2014 +@set UPDATED-MONTH September 2014 diff --git a/doc/version.texi~ b/doc/version.texi~ new file mode 100644 index 000000000..ccd67cb0c --- /dev/null +++ b/doc/version.texi~ @@ -0,0 +1,11 @@ +@ignore +Copyright (C) 1988-2014 Free Software Foundation, Inc. +@end ignore + +@set LASTCHANGE Wed Aug 27 08:43:08 EDT 2014 + +@set EDITION 4.3 +@set VERSION 4.3 + +@set UPDATED 27 August 2014 +@set UPDATED-MONTH August 2014 diff --git a/execute_cmd.c b/execute_cmd.c index 8be605389..e74d2048d 100644 --- a/execute_cmd.c +++ b/execute_cmd.c @@ -287,10 +287,10 @@ int funcnest = 0; int funcnest_max = 0; int evalnest = 0; /* bash-4.4/bash-5.0 */ -int evalnest_max = 0; +int evalnest_max = EVALNEST_MAX; int sourcenest = 0; -int sourcenest_max = 0; +int sourcenest_max = SOURCENEST_MAX; volatile int from_return_trap = 0; diff --git a/findcmd.c b/findcmd.c index 61909050a..e66769199 100644 --- a/findcmd.c +++ b/findcmd.c @@ -478,7 +478,7 @@ find_in_path_element (name, path, flags, name_len, dotinfop) int status; char *full_path, *xpath; - xpath = (*path == '~') ? bash_tilde_expand (path, 0) : path; + xpath = (posixly_correct == 0 && *path == '~') ? bash_tilde_expand (path, 0) : path; /* Remember the location of "." in the path, in all its forms (as long as they begin with a `.', e.g. `./.') */ diff --git a/findcmd.c~ b/findcmd.c~ new file mode 100644 index 000000000..61909050a --- /dev/null +++ b/findcmd.c~ @@ -0,0 +1,623 @@ +/* findcmd.c -- Functions to search for commands by name. */ + +/* Copyright (C) 1997-2012 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 3 of the License, 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. If not, see . +*/ + +#include "config.h" + +#include +#include "chartypes.h" +#include "bashtypes.h" +#if !defined (_MINIX) && defined (HAVE_SYS_FILE_H) +# include +#endif +#include "filecntl.h" +#include "posixstat.h" + +#if defined (HAVE_UNISTD_H) +# include +#endif +#include + +#include "bashansi.h" + +#include "memalloc.h" +#include "shell.h" +#include "flags.h" +#include "hashlib.h" +#include "pathexp.h" +#include "hashcmd.h" +#include "findcmd.h" /* matching prototypes and declarations */ + +#if !defined (errno) +extern int errno; +#endif + +extern int posixly_correct; +extern int last_command_exit_value; + +/* Static functions defined and used in this file. */ +static char *_find_user_command_internal __P((const char *, int)); +static char *find_user_command_internal __P((const char *, int)); +static char *find_user_command_in_path __P((const char *, char *, int)); +static char *find_in_path_element __P((const char *, char *, int, int, struct stat *)); +static char *find_absolute_program __P((const char *, int)); + +static char *get_next_path_element __P((char *, int *)); + +/* The file name which we would try to execute, except that it isn't + possible to execute it. This is the first file that matches the + name that we are looking for while we are searching $PATH for a + suitable one to execute. If we cannot find a suitable executable + file, then we use this one. */ +static char *file_to_lose_on; + +/* Non-zero if we should stat every command found in the hash table to + make sure it still exists. */ +int check_hashed_filenames = CHECKHASH_DEFAULT; + +/* DOT_FOUND_IN_SEARCH becomes non-zero when find_user_command () + encounters a `.' as the directory pathname while scanning the + list of possible pathnames; i.e., if `.' comes before the directory + containing the file of interest. */ +int dot_found_in_search = 0; + +/* Return some flags based on information about this file. + The EXISTS bit is non-zero if the file is found. + The EXECABLE bit is non-zero the file is executble. + Zero is returned if the file is not found. */ +int +file_status (name) + const char *name; +{ + struct stat finfo; + int r; + + /* Determine whether this file exists or not. */ + if (stat (name, &finfo) < 0) + return (0); + + /* If the file is a directory, then it is not "executable" in the + sense of the shell. */ + if (S_ISDIR (finfo.st_mode)) + return (FS_EXISTS|FS_DIRECTORY); + + r = FS_EXISTS; + +#if defined (HAVE_EACCESS) + /* Use eaccess(2) if we have it to take things like ACLs and other + file access mechanisms into account. eaccess uses the effective + user and group IDs, not the real ones. We could use sh_eaccess, + but we don't want any special treatment for /dev/fd. */ + if (eaccess (name, X_OK) == 0) + r |= FS_EXECABLE; + if (eaccess (name, R_OK) == 0) + r |= FS_READABLE; + + return r; +#elif defined (AFS) + /* We have to use access(2) to determine access because AFS does not + support Unix file system semantics. This may produce wrong + answers for non-AFS files when ruid != euid. I hate AFS. */ + if (access (name, X_OK) == 0) + r |= FS_EXECABLE; + if (access (name, R_OK) == 0) + r |= FS_READABLE; + + return r; +#else /* !HAVE_EACCESS && !AFS */ + + /* Find out if the file is actually executable. By definition, the + only other criteria is that the file has an execute bit set that + we can use. The same with whether or not a file is readable. */ + + /* Root only requires execute permission for any of owner, group or + others to be able to exec a file, and can read any file. */ + if (current_user.euid == (uid_t)0) + { + r |= FS_READABLE; + if (finfo.st_mode & S_IXUGO) + r |= FS_EXECABLE; + return r; + } + + /* If we are the owner of the file, the owner bits apply. */ + if (current_user.euid == finfo.st_uid) + { + if (finfo.st_mode & S_IXUSR) + r |= FS_EXECABLE; + if (finfo.st_mode & S_IRUSR) + r |= FS_READABLE; + } + + /* If we are in the owning group, the group permissions apply. */ + else if (group_member (finfo.st_gid)) + { + if (finfo.st_mode & S_IXGRP) + r |= FS_EXECABLE; + if (finfo.st_mode & S_IRGRP) + r |= FS_READABLE; + } + + /* Else we check whether `others' have permission to execute the file */ + else + { + if (finfo.st_mode & S_IXOTH) + r |= FS_EXECABLE; + if (finfo.st_mode & S_IROTH) + r |= FS_READABLE; + } + + return r; +#endif /* !AFS */ +} + +/* Return non-zero if FILE exists and is executable. + Note that this function is the definition of what an + executable file is; do not change this unless YOU know + what an executable file is. */ +int +executable_file (file) + const char *file; +{ + int s; + + s = file_status (file); +#if defined EISDIR + if (s & FS_DIRECTORY) + errno = EISDIR; /* let's see if we can improve error messages */ +#endif + return ((s & FS_EXECABLE) && ((s & FS_DIRECTORY) == 0)); +} + +int +is_directory (file) + const char *file; +{ + return (file_status (file) & FS_DIRECTORY); +} + +int +executable_or_directory (file) + const char *file; +{ + int s; + + s = file_status (file); + return ((s & FS_EXECABLE) || (s & FS_DIRECTORY)); +} + +/* Locate the executable file referenced by NAME, searching along + the contents of the shell PATH variable. Return a new string + which is the full pathname to the file, or NULL if the file + couldn't be found. If a file is found that isn't executable, + and that is the only match, then return that. */ +char * +find_user_command (name) + const char *name; +{ + return (find_user_command_internal (name, FS_EXEC_PREFERRED|FS_NODIRS)); +} + +/* Locate the file referenced by NAME, searching along the contents + of the shell PATH variable. Return a new string which is the full + pathname to the file, or NULL if the file couldn't be found. This + returns the first readable file found; designed to be used to look + for shell scripts or files to source. */ +char * +find_path_file (name) + const char *name; +{ + return (find_user_command_internal (name, FS_READABLE)); +} + +static char * +_find_user_command_internal (name, flags) + const char *name; + int flags; +{ + char *path_list, *cmd; + SHELL_VAR *var; + + /* Search for the value of PATH in both the temporary environments and + in the regular list of variables. */ + if (var = find_variable_tempenv ("PATH")) /* XXX could be array? */ + path_list = value_cell (var); + else + path_list = (char *)NULL; + + if (path_list == 0 || *path_list == '\0') + return (savestring (name)); + + cmd = find_user_command_in_path (name, path_list, flags); + + return (cmd); +} + +static char * +find_user_command_internal (name, flags) + const char *name; + int flags; +{ +#ifdef __WIN32__ + char *res, *dotexe; + + dotexe = (char *)xmalloc (strlen (name) + 5); + strcpy (dotexe, name); + strcat (dotexe, ".exe"); + res = _find_user_command_internal (dotexe, flags); + free (dotexe); + if (res == 0) + res = _find_user_command_internal (name, flags); + return res; +#else + return (_find_user_command_internal (name, flags)); +#endif +} + +/* Return the next element from PATH_LIST, a colon separated list of + paths. PATH_INDEX_POINTER is the address of an index into PATH_LIST; + the index is modified by this function. + Return the next element of PATH_LIST or NULL if there are no more. */ +static char * +get_next_path_element (path_list, path_index_pointer) + char *path_list; + int *path_index_pointer; +{ + char *path; + + path = extract_colon_unit (path_list, path_index_pointer); + + if (path == 0) + return (path); + + if (*path == '\0') + { + free (path); + path = savestring ("."); + } + + return (path); +} + +/* Look for PATHNAME in $PATH. Returns either the hashed command + corresponding to PATHNAME or the first instance of PATHNAME found + in $PATH. If (FLAGS&1) is non-zero, insert the instance of PATHNAME + found in $PATH into the command hash table. Returns a newly-allocated + string. */ +char * +search_for_command (pathname, flags) + const char *pathname; + int flags; +{ + char *hashed_file, *command; + int temp_path, st; + SHELL_VAR *path; + + hashed_file = command = (char *)NULL; + + /* If PATH is in the temporary environment for this command, don't use the + hash table to search for the full pathname. */ + path = find_variable_tempenv ("PATH"); + temp_path = path && tempvar_p (path); + if (temp_path == 0 && path) + path = (SHELL_VAR *)NULL; + + /* Don't waste time trying to find hashed data for a pathname + that is already completely specified or if we're using a command- + specific value for PATH. */ + if (path == 0 && absolute_program (pathname) == 0) + hashed_file = phash_search (pathname); + + /* If a command found in the hash table no longer exists, we need to + look for it in $PATH. Thank you Posix.2. This forces us to stat + every command found in the hash table. */ + + if (hashed_file && (posixly_correct || check_hashed_filenames)) + { + st = file_status (hashed_file); + if ((st & (FS_EXISTS|FS_EXECABLE)) != (FS_EXISTS|FS_EXECABLE)) + { + phash_remove (pathname); + free (hashed_file); + hashed_file = (char *)NULL; + } + } + + if (hashed_file) + command = hashed_file; + else if (absolute_program (pathname)) + /* A command containing a slash is not looked up in PATH or saved in + the hash table. */ + command = savestring (pathname); + else + { + /* If $PATH is in the temporary environment, we've already retrieved + it, so don't bother trying again. */ + if (temp_path) + { + command = find_user_command_in_path (pathname, value_cell (path), + FS_EXEC_PREFERRED|FS_NODIRS); + } + else + command = find_user_command (pathname); + if (command && hashing_enabled && temp_path == 0 && (flags & 1)) + phash_insert ((char *)pathname, command, dot_found_in_search, 1); /* XXX fix const later */ + } + return (command); +} + +char * +user_command_matches (name, flags, state) + const char *name; + int flags, state; +{ + register int i; + int path_index, name_len; + char *path_list, *path_element, *match; + struct stat dotinfo; + static char **match_list = NULL; + static int match_list_size = 0; + static int match_index = 0; + + if (state == 0) + { + /* Create the list of matches. */ + if (match_list == 0) + { + match_list_size = 5; + match_list = strvec_create (match_list_size); + } + + /* Clear out the old match list. */ + for (i = 0; i < match_list_size; i++) + match_list[i] = 0; + + /* We haven't found any files yet. */ + match_index = 0; + + if (absolute_program (name)) + { + match_list[0] = find_absolute_program (name, flags); + match_list[1] = (char *)NULL; + path_list = (char *)NULL; + } + else + { + name_len = strlen (name); + file_to_lose_on = (char *)NULL; + dot_found_in_search = 0; + if (stat (".", &dotinfo) < 0) + dotinfo.st_dev = dotinfo.st_ino = 0; /* so same_file won't match */ + path_list = get_string_value ("PATH"); + path_index = 0; + } + + while (path_list && path_list[path_index]) + { + path_element = get_next_path_element (path_list, &path_index); + + if (path_element == 0) + break; + + match = find_in_path_element (name, path_element, flags, name_len, &dotinfo); + + free (path_element); + + if (match == 0) + continue; + + if (match_index + 1 == match_list_size) + { + match_list_size += 10; + match_list = strvec_resize (match_list, (match_list_size + 1)); + } + + match_list[match_index++] = match; + match_list[match_index] = (char *)NULL; + FREE (file_to_lose_on); + file_to_lose_on = (char *)NULL; + } + + /* We haven't returned any strings yet. */ + match_index = 0; + } + + match = match_list[match_index]; + + if (match) + match_index++; + + return (match); +} + +static char * +find_absolute_program (name, flags) + const char *name; + int flags; +{ + int st; + + st = file_status (name); + + /* If the file doesn't exist, quit now. */ + if ((st & FS_EXISTS) == 0) + return ((char *)NULL); + + /* If we only care about whether the file exists or not, return + this filename. Otherwise, maybe we care about whether this + file is executable. If it is, and that is what we want, return it. */ + if ((flags & FS_EXISTS) || ((flags & FS_EXEC_ONLY) && (st & FS_EXECABLE))) + return (savestring (name)); + + return (NULL); +} + +static char * +find_in_path_element (name, path, flags, name_len, dotinfop) + const char *name; + char *path; + int flags, name_len; + struct stat *dotinfop; +{ + int status; + char *full_path, *xpath; + + xpath = (*path == '~') ? bash_tilde_expand (path, 0) : path; + + /* Remember the location of "." in the path, in all its forms + (as long as they begin with a `.', e.g. `./.') */ + if (dot_found_in_search == 0 && *xpath == '.') + dot_found_in_search = same_file (".", xpath, dotinfop, (struct stat *)NULL); + + full_path = sh_makepath (xpath, name, 0); + + status = file_status (full_path); + + if (xpath != path) + free (xpath); + + if ((status & FS_EXISTS) == 0) + { + free (full_path); + return ((char *)NULL); + } + + /* The file exists. If the caller simply wants the first file, here it is. */ + if (flags & FS_EXISTS) + return (full_path); + + /* If we have a readable file, and the caller wants a readable file, this + is it. */ + if ((flags & FS_READABLE) && (status & FS_READABLE)) + return (full_path); + + /* If the file is executable, then it satisfies the cases of + EXEC_ONLY and EXEC_PREFERRED. Return this file unconditionally. */ + if ((status & FS_EXECABLE) && (flags & (FS_EXEC_ONLY|FS_EXEC_PREFERRED)) && + (((flags & FS_NODIRS) == 0) || ((status & FS_DIRECTORY) == 0))) + { + FREE (file_to_lose_on); + file_to_lose_on = (char *)NULL; + return (full_path); + } + + /* The file is not executable, but it does exist. If we prefer + an executable, then remember this one if it is the first one + we have found. */ + if ((flags & FS_EXEC_PREFERRED) && file_to_lose_on == 0) + file_to_lose_on = savestring (full_path); + + /* If we want only executable files, or we don't want directories and + this file is a directory, or we want a readable file and this file + isn't readable, fail. */ + if ((flags & (FS_EXEC_ONLY|FS_EXEC_PREFERRED)) || + ((flags & FS_NODIRS) && (status & FS_DIRECTORY)) || + ((flags & FS_READABLE) && (status & FS_READABLE) == 0)) + { + free (full_path); + return ((char *)NULL); + } + else + return (full_path); +} + +/* This does the dirty work for find_user_command_internal () and + user_command_matches (). + NAME is the name of the file to search for. + PATH_LIST is a colon separated list of directories to search. + FLAGS contains bit fields which control the files which are eligible. + Some values are: + FS_EXEC_ONLY: The file must be an executable to be found. + FS_EXEC_PREFERRED: If we can't find an executable, then the + the first file matching NAME will do. + FS_EXISTS: The first file found will do. + FS_NODIRS: Don't find any directories. +*/ +static char * +find_user_command_in_path (name, path_list, flags) + const char *name; + char *path_list; + int flags; +{ + char *full_path, *path; + int path_index, name_len; + struct stat dotinfo; + + /* We haven't started looking, so we certainly haven't seen + a `.' as the directory path yet. */ + dot_found_in_search = 0; + + if (absolute_program (name)) + { + full_path = find_absolute_program (name, flags); + return (full_path); + } + + if (path_list == 0 || *path_list == '\0') + return (savestring (name)); /* XXX */ + + file_to_lose_on = (char *)NULL; + name_len = strlen (name); + if (stat (".", &dotinfo) < 0) + dotinfo.st_dev = dotinfo.st_ino = 0; + path_index = 0; + + while (path_list[path_index]) + { + /* Allow the user to interrupt out of a lengthy path search. */ + QUIT; + + path = get_next_path_element (path_list, &path_index); + if (path == 0) + break; + + /* Side effects: sets dot_found_in_search, possibly sets + file_to_lose_on. */ + full_path = find_in_path_element (name, path, flags, name_len, &dotinfo); + free (path); + + /* This should really be in find_in_path_element, but there isn't the + right combination of flags. */ + if (full_path && is_directory (full_path)) + { + free (full_path); + continue; + } + + if (full_path) + { + FREE (file_to_lose_on); + return (full_path); + } + } + + /* We didn't find exactly what the user was looking for. Return + the contents of FILE_TO_LOSE_ON which is NULL when the search + required an executable, or non-NULL if a file was found and the + search would accept a non-executable as a last resort. If the + caller specified FS_NODIRS, and file_to_lose_on is a directory, + return NULL. */ + if (file_to_lose_on && (flags & FS_NODIRS) && is_directory (file_to_lose_on)) + { + free (file_to_lose_on); + file_to_lose_on = (char *)NULL; + } + + return (file_to_lose_on); +} diff --git a/subst.h b/subst.h index d8103b799..6a4110e39 100644 --- a/subst.h +++ b/subst.h @@ -47,7 +47,6 @@ #define ASS_MKASSOC 0x0004 #define ASS_MKGLOBAL 0x0008 /* force global assignment */ #define ASS_NAMEREF 0x0010 /* assigning to nameref variable */ -#define ASS_FROMREF 0x0020 /* assigning from value of nameref variable */ /* Flags for the string extraction functions. */ #define SX_NOALLOC 0x0001 /* just skip; don't return substring */ diff --git a/variables.c b/variables.c index 448595283..b7b6d496a 100644 --- a/variables.c +++ b/variables.c @@ -2687,7 +2687,6 @@ bind_variable (name, value, flags) SHELL_VAR *v, *nv; VAR_CONTEXT *vc, *nvc; int level; - char *newname; if (shell_variables == 0) create_variable_tables ();