# Command built-in

The command built-in executes or identifies a command.

## Syntax

- `command [-befp] command [argument…]`

- `command -v|-V [-abefkp] command…`

## Description

Without the `-v` (`--identify`) or `-V` (`--verbose-identify`) option, the built-in executes command with arguments in the same manner as the last step of execution of simple commands. The command is treated as a built-in or external command or a function according to the options specified to the command built-in. The shell does not exit on argument syntax error etc. even if the command is a special built-in

With the `-v` (`--identify`) option, command is identified. If the command is found in `$PATH`, its full pathname is printed. If it is a keyword, function, or built-in that is not found in `$PATH`, the command name is simply printed. If it is an alias, it is printed in the form like `alias ll='ls -l'`. If the command is not found, nothing is printed and the exit status is non-zero.

The `-V` (`--verbose-identify`) option is similar to the `-v` (`--identify`) option, but the output format is more human-friendly.

## Options

`-a`
`--alias`

  Search for the command as an alias. Must be used with the `-v` (`--identify`) or `-V` (`--verbose-identify`) option.

`-b`
`--builtin-command`

  Search for the command as a built-in.

`-e`
`--external-command`

  Search for the command as an external command.

`-f`
`--function`

  Search for the command as a function.

`-k`
`--keyword`

  Search for the command as a keyword. Must be used with the `-v` (`--identify`) or `-V` (`--verbose-identify`) option.

`-p`
`--standard-path`

  Search the system’s default `PATH` instead of the current `$PATH`.

`-v`
`--identify`

  Identify commands and print in the format defined in the POSIX standard.

`-V`
`--verbose-identify`

  Identify commands and print in a human-friendly format.

If none of the `-a` (`--alias`), `-b` (`--builtin-command`), `-e` (`--external-command`), `-f` (`--function`), and `-k` (`--keyword`) options is specified, the followings are assumed:

Without the `-v` (`--identify`) or `-V` (`--verbose-identify`) option

  `-b -e`

With the `-v` (`--identify`) or `-V` (`--verbose-identify`) option

  `-a -b -e -f -k`

## Operands

command

  A command to be executed or identified.

argument…

  Arguments passed to the executed command.

## Exit status

The exit status of the command built-in is:

Without the `-v` (`--identify`) or `-V` (`--verbose-identify`) option

  the exit status of the executed command.

With the `-v` (`--identify`) or `-V` (`--verbose-identify`) option

  zero unless there is any error.

## Notes

The command built-in is a semi-special built-in.

In the POSIXly-correct mode, options other than `-p`, `-v`, and `-V` cannot be used and at most one command can be specified. The POSIX standard does not allow specifying `-v` and `-V` at a time, but yash do (only the last specified one is effective).