(features.info)Bash Builtins

Bash Builtin Commands
=====================

   This section describes builtin commands which are unique to or have
been extended in Bash.

`builtin'
          builtin [SHELL-BUILTIN [ARGS]]
     Run a shell builtin.  This is useful when you wish to rename a
     shell builtin to be a function, but need the functionality of the
     builtin within the function itself.

`bind'
          bind [-m KEYMAP] [-lvd] [-q NAME]
          bind [-m KEYMAP] -f FILENAME
          bind [-m KEYMAP] KEYSEQ:FUNCTION-NAME

     Display current Readline (Note: Command Line Editing.) key and
     function bindings, or bind a key sequence to a Readline function
     or macro.  The binding syntax accepted is identical to that of
     `.inputrc' (Note: Readline Init File.), but each binding must be
     passed as a separate argument: `"\C-x\C-r":re-read-init-file'.
     Options, if supplied, have the following meanings:

    `-m keymap'
          Use KEYMAP as the keymap to be affected by the subsequent
          bindings.  Acceptable KEYMAP names are `emacs',
          `emacs-standard', `emacs-meta', `emacs-ctlx', `vi', `vi-move',
          `vi-command', and `vi-insert'.  `vi' is equivalent to
          `vi-command'; `emacs' is equivalent to `emacs-standard'.

    `-l'
          List the names of all readline functions

    `-v'
          List current function names and bindings

    `-d'
          Dump function names and bindings in such a way that they can
          be re-read

    `-f filename'
          Read key bindings from FILENAME

    `-q'
          Query about which keys invoke the named FUNCTION

`command'
          command [-pVv] COMMAND [ARGS ...]
     Runs COMMAND with ARG ignoring shell functions.  If you have a
     shell function called `ls', and you wish to call the command `ls',
     you can say `command ls'.  The `-p' option means to use a default
     value for `$PATH' that is guaranteed to find all of the standard
     utilities.

     If either the `-V' or `-v' option is supplied, a description of
     COMMAND is printed.  The `-v' option causes a single word
     indicating the command or file name used to invoke COMMAND to be
     printed; the `-V' option produces a more verbose description.

`declare'
          declare [-frxi] [NAME[=VALUE]]

     Declare variables and/or give them attributes.  If no NAMEs are
     given, then display the values of variables instead.  `-f' means
     to use function names only.  `-r' says to make NAMEs readonly.
     `-x' says to mark NAMEs for export.  `-i' says that the variable
     is to be treated as an integer; arithmetic evaluation (Note: Shell
     Arithmetic.) is performed when the variable is assigned a value.
     Using `+' instead of `-' turns off the attribute instead.  When
     used in a function, `declare' makes NAMEs local, as with the
     `local' command.

`enable'
          enable [-n] [-a] [NAME ...]
     Enable and disable builtin shell commands.  This allows you to use
     a disk command which has the same name as a shell builtin.  If
     `-n' is used, the NAMEs become disabled.  Otherwise NAMEs are
     enabled.  For example, to use the `test' binary found via `$PATH'
     instead of the shell builtin version, type `enable -n test'.  The
     `-a' option means to list each builtin with an indication of
     whether or not it is enabled.

`help'
          help [PATTERN]
     Display helpful information about builtin commands.  If PATTERN is
     specified, `help' gives detailed help on all commands matching
     PATTERN, otherwise a list of the builtins is printed.

`local'
          local NAME[=VALUE]
     For each argument, create a local variable called NAME, and give
     it VALUE.  `local' can only be used within a function; it makes
     the variable NAME have a visible scope restricted to that function
     and its children.

`type'
          type [-all] [-type | -path] [NAME ...]
     For each NAME, indicate how it would be interpreted if used as a
     command name.

     If the `-type' flag is used, `type' returns a single word which is
     one of "alias", "function", "builtin", "file" or "keyword", if
     NAME is an alias, shell function, shell builtin, disk file, or
     shell reserved word, respectively.

     If the `-path' flag is used, `type' either returns the name of the
     disk file that would be executed, or nothing if `-type' would not
     return "file".

     If the `-all' flag is used, returns all of the places that contain
     an executable named FILE.  This includes aliases and functions, if
     and only if the `-path' flag is not also used.

     `Type' accepts `-a', `-t', and `-p' as equivalent to `-all',
     `-type', and `-path', respectively.

`ulimit'
          ulimit [-acdmstfpnuvSH] [LIMIT]
     `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:
    `-S'
          change and report the soft limit associated with a resource
          (the default if the `-H' option is not given).

    `-H'
          change and report the hard limit associated with a resource.

    `-a'
          all current limits are reported.

    `-c'
          the maximum size of core files created.

    `-d'
          the maximum size of a process's data segment.

    `-m'
          the maximum resident set size.

    `-s'
          the maximum stack size.

    `-t'
          the maximum amount of cpu time in seconds.

    `-f'
          the maximum size of files created by the shell.

    `-p'
          the pipe buffer size.

    `-n'
          the maximum number of open file descriptors.

    `-u'
          the maximum number of processes available to a single user.

    `-v'
          the maximum amount of virtual memory available to the process.

     If LIMIT is given, it is the new value of the specified resource.
     Otherwise, the current value of the specified resource is printed.
     If no option is given, then `-f' is assumed.  Values are in
     1024-byte increments, except for `-t', which is in seconds, `-p',
     which is in units of 512-byte blocks, and `-n' and `-u', which are
     unscaled values.