Command (Unix)

command is a shell command for Unix and Unix-like operating systems. It is used to execute a command whilst suppressing normal shell function lookup.^[1]

It is specified in the POSIX standard and is often implemented in Unix shells as a shell builtin function. Built-in functions take precedence over programs when resolving the name of a command. A user may suppress the lookup of built-in functions in order to execute a program with the same name as a built-in function.^{[citation needed]}

The arguments passed specify the name of the command to be executed, along with its arguments. If the specified command name is the name of a shell built-in function, the command will be processed as if such function did not exist. In all other circumstances the command will be processed as normal.^[2]

In the following, the ls command is run without any shell functions or aliases that may exist with the same name:

$ command ls

• List of Unix commands

• command – Shell and Utilities Reference, The Single UNIX Specification, Version 5 from The Open Group