which



WHICH(1)                                                              WHICH(1)




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 exe-
       cuted 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 itself. 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 func-
           tion 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 explic-
           ity 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 success-
           fully.

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


RETURN VALUE

       Which returns the number of failed arguments, or -1 when no `program-
       name┬┤ was given.


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.


AUTHOR

       Carlo Wood <carlo@gnu.org>


SEE ALSO

       bash(1)



                                                                      WHICH(1)

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