builtins/reserved.def

   1 This file is reserved.def, in which the shell reserved words are defined.
   2 It has no direct C file production, but defines builtins for the Bash
   3 builtin help command.
   4
   5 Copyright (C) 1987-2006 Free Software Foundation, Inc.
   6
   7 This file is part of GNU Bash, the Bourne Again SHell.
   8
   9 Bash is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 2, or (at your option) any later
  12 version.
  13
  14 Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License along
  20 with Bash; see the file COPYING.  If not, write to the Free Software
  21 Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.
  22
  23 $BUILTIN for
  24 $SHORT_DOC for NAME [in WORDS ... ;] do COMMANDS; done
  25 The `for' loop executes a sequence of commands for each member in a
  26 list of items.  If `in WORDS ...;' is not present, then `in "$@"' is
  27 assumed.  For each element in WORDS, NAME is set to that element, and
  28 the COMMANDS are executed.
  29 $END
  30
  31 $BUILTIN for ((
  32 $DOCNAME arith_for
  33 $SHORT_DOC for (( exp1; exp2; exp3 )); do COMMANDS; done
  34 Equivalent to
  35         (( EXP1 ))
  36         while (( EXP2 )); do
  37                 COMMANDS
  38                 (( EXP3 ))
  39         done
  40 EXP1, EXP2, and EXP3 are arithmetic expressions.  If any expression is
  41 omitted, it behaves as if it evaluates to 1.
  42 $END
  43
  44 $BUILTIN select
  45 $SHORT_DOC select NAME [in WORDS ... ;] do COMMANDS; done
  46 The WORDS are expanded, generating a list of words.  The
  47 set of expanded words is printed on the standard error, each
  48 preceded by a number.  If `in WORDS' is not present, `in "$@"'
  49 is assumed.  The PS3 prompt is then displayed and a line read
  50 from the standard input.  If the line consists of the number
  51 corresponding to one of the displayed words, then NAME is set
  52 to that word.  If the line is empty, WORDS and the prompt are
  53 redisplayed.  If EOF is read, the command completes.  Any other
  54 value read causes NAME to be set to null.  The line read is saved
  55 in the variable REPLY.  COMMANDS are executed after each selection
  56 until a break command is executed.
  57 $END
  58
  59 $BUILTIN time
  60 $SHORT_DOC time [-p] PIPELINE
  61 Execute PIPELINE and print a summary of the real time, user CPU time,
  62 and system CPU time spent executing PIPELINE when it terminates.
  63 The return status is the return status of PIPELINE.  The `-p' option
  64 prints the timing summary in a slightly different format.  This uses
  65 the value of the TIMEFORMAT variable as the output format.
  66 $END
  67
  68 $BUILTIN case
  69 $SHORT_DOC case WORD in [PATTERN [| PATTERN]...) COMMANDS ;;]... esac
  70 Selectively execute COMMANDS based upon WORD matching PATTERN.  The
  71 `|' is used to separate multiple patterns.
  72 $END
  73
  74 $BUILTIN if
  75 $SHORT_DOC if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]... [ else COMMANDS; ] fi
  76 The `if COMMANDS' list is executed.  If its exit status is zero, then the
  77 `then COMMANDS' list is executed.  Otherwise, each `elif COMMANDS' list is
  78 executed in turn, and if its exit status is zero, the corresponding
  79 `then COMMANDS' list is executed and the if command completes.  Otherwise,
  80 the `else COMMANDS' list is executed, if present.  The exit status of the
  81 entire construct is the exit status of the last command executed, or zero
  82 if no condition tested true.
  83 $END
  84
  85 $BUILTIN while
  86 $SHORT_DOC while COMMANDS; do COMMANDS; done
  87 Expand and execute COMMANDS as long as the final command in the
  88 `while' COMMANDS has an exit status of zero.
  89 $END
  90
  91 $BUILTIN until
  92 $SHORT_DOC until COMMANDS; do COMMANDS; done
  93 Expand and execute COMMANDS as long as the final command in the
  94 `until' COMMANDS has an exit status which is not zero.
  95 $END
  96
  97 $BUILTIN function
  98 $SHORT_DOC function NAME { COMMANDS ; } or NAME () { COMMANDS ; }
  99 Create a simple command invoked by NAME which runs COMMANDS.
 100 Arguments on the command line along with NAME are passed to the
 101 function as $0 .. $n.
 102 $END
 103
 104 $BUILTIN { ... }
 105 $DOCNAME grouping_braces
 106 $SHORT_DOC { COMMANDS ; }
 107 Run a set of commands in a group.  This is one way to redirect an
 108 entire set of commands.
 109 $END
 110
 111 $BUILTIN %
 112 $DOCNAME fg_percent
 113 $SHORT_DOC JOB_SPEC [&]
 114 Equivalent to the JOB_SPEC argument to the `fg' command.  Resume a
 115 stopped or background job.  JOB_SPEC can specify either a job name
 116 or a job number.  Following JOB_SPEC with a `&' places the job in
 117 the background, as if the job specification had been supplied as an
 118 argument to `bg'.
 119 $END
 120
 121 $BUILTIN (( ... ))
 122 $DOCNAME arith
 123 $SHORT_DOC (( expression ))
 124 The EXPRESSION is evaluated according to the rules for arithmetic
 125 evaluation.  Equivalent to "let EXPRESSION".
 126 $END
 127
 128 $BUILTIN [[ ... ]]
 129 $DOCNAME conditional
 130 $SHORT_DOC [[ expression ]]
 131 Returns a status of 0 or 1 depending on the evaluation of the conditional
 132 expression EXPRESSION.  Expressions are composed of the same primaries used
 133 by the `test' builtin, and may be combined using the following operators
 134
 135         ( EXPRESSION )  Returns the value of EXPRESSION
 136         ! EXPRESSION    True if EXPRESSION is false; else false
 137         EXPR1 && EXPR2  True if both EXPR1 and EXPR2 are true; else false
 138         EXPR1 || EXPR2  True if either EXPR1 or EXPR2 is true; else false
 139
 140 When the `==' and `!=' operators are used, the string to the right of the
 141 operator is used as a pattern and pattern matching is performed.  The
 142 && and || operators do not evaluate EXPR2 if EXPR1 is sufficient to
 143 determine the expression's value.
 144 $END
 145
 146 $BUILTIN variables
 147 $DOCNAME variable_help
 148 $SHORT_DOC variables - Some variable names and meanings
 149 BASH_VERSION    Version information for this Bash.
 150 CDPATH  A colon-separated list of directories to search
 151                 for directries given as arguments to `cd'.
 152 GLOBIGNORE      A colon-separated list of patterns describing filenames to
 153                 be ignored by pathname expansion.
 154 #if defined (HISTORY)
 155 HISTFILE        The name of the file where your command history is stored.
 156 HISTFILESIZE    The maximum number of lines this file can contain.
 157 HISTSIZE        The maximum number of history lines that a running
 158                 shell can access.
 159 #endif /* HISTORY */
 160 HOME    The complete pathname to your login directory.
 161 HOSTNAME        The name of the current host.
 162 HOSTTYPE        The type of CPU this version of Bash is running under.
 163 IGNOREEOF       Controls the action of the shell on receipt of an EOF
 164                 character as the sole input.  If set, then the value
 165                 of it is the number of EOF characters that can be seen
 166                 in a row on an empty line before the shell will exit
 167                 (default 10).  When unset, EOF signifies the end of input.
 168 MACHTYPE        A string describing the current system Bash is running on.
 169 MAILCHECK       How often, in seconds, Bash checks for new mail.
 170 MAILPATH        A colon-separated list of filenames which Bash checks
 171                 for new mail.
 172 OSTYPE  The version of Unix this version of Bash is running on.
 173 PATH    A colon-separated list of directories to search when
 174                 looking for commands.
 175 PROMPT_COMMAND  A command to be executed before the printing of each
 176                 primary prompt.
 177 PS1             The primary prompt string.
 178 PS2             The secondary prompt string.
 179 PWD             The full pathname of the current directory.
 180 SHELLOPTS       A colon-separated list of enabled shell options.
 181 TERM    The name of the current terminal type.
 182 TIMEFORMAT      The output format for timing statistics displayed by the
 183                 `time' reserved word.
 184 auto_resume     Non-null means a command word appearing on a line by
 185                 itself is first looked for in the list of currently
 186                 stopped jobs.  If found there, that job is foregrounded.
 187                 A value of `exact' means that the command word must
 188                 exactly match a command in the list of stopped jobs.  A
 189                 value of `substring' means that the command word must
 190                 match a substring of the job.  Any other value means that
 191                 the command must be a prefix of a stopped job.
 192 #if defined (HISTORY)
 193 #  if defined (BANG_HISTORY)
 194 histchars       Characters controlling history expansion and quick
 195                 substitution.  The first character is the history
 196                 substitution character, usually `!'.  The second is
 197                 the `quick substitution' character, usually `^'.  The
 198                 third is the `history comment' character, usually `#'.
 199 #  endif /* BANG_HISTORY */
 200 HISTIGNORE      A colon-separated list of patterns used to decide which
 201                 commands should be saved on the history list.
 202 #endif /* HISTORY */
 203 $END