Provided by: debianutils_4.2.1ubuntu2_i386
which - locate a command
which [-a] filename ...
which returns the pathnames of the files (or links) which would be
executed in the current environment, had its arguments been given as
commands in a strictly POSIX-conformant shell. It does this by
searching the PATH for executable files matching the names of the
arguments. It does not follow symbolic links.
-a print all matching pathnames of each argument
0 if all specified commands are found and executable
1 if one or more specified commands is nonexistent or not
2 if an invalid option is specified