which1
Locate a program file in the user's path
Usage
which [-as]
program ...
Overview
The which utility takes a list of command names and searches the path for each executable file that would be run had these commands actually been invoked.
The following options are available:
-
-a -
List all instances of executables found (instead of just the first one of each).
-
-s -
No output, just return 0 if all of the executables are found, or 1 if some were not found.
Some shells may provide a builtin which command which is similar or identical to this utility. Consult the builtin(1) manual page.
Examples
Locate the ls(1) and cp(1) commands:
$ /usr/bin/which ls cp /bin/ls /bin/cp
Same as above with a specific PATH and showing all occurrences:
$ PATH=/bin:/rescue /usr/bin/which -a ls cp /bin/ls /rescue/ls /bin/cp /rescue/cp
which will show duplicates if the same executable is found more than once:
$ PATH=/bin:/bin /usr/bin/which -a ls /bin/ls /bin/ls
Do not show output. Just exit with an appropriate return code:
$ /usr/bin/which -s ls cp $ echo $? 0 $ /usr/bin/which -s fakecommand $ echo $? 1
Releases
163 releases since Mac OS X 10.0; the text changed 4 times.
-a since Mac OS X 10.5;
-s since Mac OS X 10.5.