WHICH(1) BSD Reference Manual WHICH(1)
which - locate a program file (or files) in the path
which [-a] name [...]
which takes a list of names and looks for the files which would be exe- cuted had these names been given as commands. Each argument is searched for along the user's path. If the -a flag is given, which will return a list of all matches instead of just the first match. The which utility exits with one of the following values: 0 All names were successfully resolved. 1 Some names were resolved but not all. 2 No names were resolved. -1 A system error occurred.
The following environment variables affect the execution of which: PATH A colon-separated list of directories in which to find executables. If PATH is not set, and the given name is not a fully qualified or relative pathname, which will fail.
A diagnostic is given if an executable file with the argument name was not found in the path.
csh(1), find(1), locate(1), sh(1), whereis(1), environ(7)
A which command appeared in 3.0BSD.
The which command formerly was a csh(1) script and could expand aliases. csh(1) now has a built-in which command so this version is intended for use with other shells like sh(1). MirBSD #10-current February 21, 1997 1