Which Command

NAME

       which - shows the full path of (shell) commands.

SYNOPSIS

       which [options] [--] programname [...]

DESCRIPTION

       Which takes one or more arguments. For each of its arguments it prints to stdout the full path of the executables that would have been executed when this argument had been entered at the shell prompt. It does this by searching for an executable or script in the directories listed in the environment variable PATH using the same algorithm as bash(1).

      This man page is generated from the file which.texinfo.

OPTIONS

       --all, -a           Print all matching executables in PATH, not just the first.

       --read-alias, -I Read aliases from stdin, reporting matching ones on stdout. This is useful in combination with using an alias for which it self. For example

           alias which=´alias | which -i´.

       --skip-alias            Ignore option `--read-alias´, if any. This is useful to explicity search for normal binaries, while using the `--read-alias´ option in an alias or function for which.

       --read-functions     Read shell function definitions from stdin, reporting matching ones on stdout. This is useful in combination with using a shell function for which itself.  For example:

           which() { declare -f | which --read-functions $@ }

           export -f which

       --skip-functions       Ignore option `--read-functions´, if any. This is useful to explicity search for normal binaries, while using the `--read-functions´ option in an alias or function for which.

--skip-dot           Skip directories in PATH that start with a dot.

--skip-tilde         Skip directories in PATH that start with a tilde and executables which reside in the HOME directory.

--show-dot         If a directory in PATH starts with a dot and a matching executable was found for that path, then print "./programname" rather than the full path.

--show-tilde       Output a tilde when a directory matches the HOME directory. This option is ignored when which is invoked as root.

--tty-only          Stop processing options on the right if not on tty.

--version,-v,-V  Print version information on standard output then exit successfully.

 --help              Print usage information on standard output then exit successfully.

EXAMPLE

      The recommended way to use this utility is by adding an alias (C shell) or shell function (Bourne shell) for which like the following:

       [ba]sh:

       which ()

            {

              (alias; declare -f) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot $@

            }

            export -f which

       [t]csh:

alias which ´alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde´

This  will  print  the readable ~/ and ./ when starting which from your prompt, while still printing the full path when used from a script:

            > which q2

            ~/bin/q2

            > echo `which q2`

            /home/carlo/bin/q2

BUGS

       The HOME directory is determined by looking for the HOME environment variable,which  aborts  when this variable doesn´t exist.  Which will consider two equivalent directories to be different when  one  of  them contains a path with a symbolic link.