Which (Unix)
Encyclopedia
which is a Unix
command used to identify the location of executable
s.
The command takes one or more arguments; for each of these arguments, it prints to stdout the full path of the executable that would have been executed if this argument had been entered into the shell
. It does this by searching for an executable or script in the directories listed in the environment variable PATH
. The which command is part of most Unix-like
computers; and is also available as a separate package for Microsoft Windows
.
The functionality of the which command is similar to some implementations of the type
command. Posix
specifies a command named command that also covers this functionality.
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
command used to identify the location of executable
Executable
In computing, an executable file causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a data file that must be parsed by a program to be meaningful. These instructions are traditionally machine code instructions for a physical CPU...
s.
The command takes one or more arguments; for each of these arguments, it prints to stdout the full path of the executable that would have been executed if this argument had been entered into the shell
Unix shell
A Unix shell is a command-line interpreter or shell that provides a traditional user interface for the Unix operating system and for Unix-like systems...
. It does this by searching for an executable or script in the directories listed in the environment variable PATH
Path (variable)
PATH is an environment variable on Unix-like operating systems, DOS, OS/2, and Microsoft Windows, specifying a set of directories where executable programs are located...
. The which command is part of most Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
computers; and is also available as a separate package for Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
.
The functionality of the which command is similar to some implementations of the type
Type (Unix)
type is a Unix command that describes how its arguments would be interpreted if used as command names.-Function:Where applicable, type will display the command name's path...
command. Posix
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
specifies a command named command that also covers this functionality.