command(C)

command -- execute a simple command

Syntax

command [ -p ] name [ argument ... ]

command [ -v | -V ] name

Description

command executes the command name together with its arguments.

command stops the shell looking for a function defined within it with the same name as the command name. This may be used to prevent a function from calling itself recursively (see ``Examples'').

If the command name is a special built-in utility (such as eval, exec, and set), any variable assignments do not remain in effect in the environment of the shell after the utility has finished executing. Also, syntax errors will not cause the shell to abort.

Using command to execute a command name that is not a shell function or a special built-in utility is identical to invoking name in its own right.

You can find out what type of command the current shell thinks name is by using the options -v or -V.

command accepts the following options:

-p

Use a default value for PATH that finds all the standard utilities.

-v

Print to the standard output:

the absolute pathname of the command name if name exists in one of the directories specified by PATH, or if it is a regular built-in utility associated with PATH
name itself if it is a special or regular built-in shell utility, function, or reserved word
an alias definition if name is an alias
nothing if no match to name is found

-V

Prints the same information as -v in a more verbose form including the assumed category of name:

utilities, regular built-in utilities, and functions found using the variable PATH
shell functions
aliases
special built-in utilities
regular built-in utilities not associated with PATH
shell reserved words

Exit values

command used with the -v or -V options has the following exit values:

0: successful completion
>0: name could not be found or an error occurred in command

Otherwise, command returns:

126: name was found but it could not be executed
127: name could not be found, or an error occurred in command

Any other value is the exit value returned by the command name.

Examples

Define a function cd() that prints the new working directory (note that command prevents this function from being recursive):

   cd()	{
   	command cd "$@" > /dev/null
   	pwd
   	}

Stop a special built-in utility from aborting the shell; for example when trying to redirect the standard output to a file that has the wrong permissions:

   command exec > file_with_mode_0000

Execute getconf(C) to get the default system path without assuming that PATH is already set up:

   command -p getconf CS_PATH

Limitations

command is available in ksh(C) only.

Standards conformance

command is conformant with:

ISO/IEC DIS 99452:1992, Information technology Portable Operating System Interface (POSIX) Part 2: Shell and Utilities (IEEE Std 1003.21992);
X/Open CAE Specification, Commands and Utilities, Issue 4, 1992.