which - shows the full path of (shell) commands.
SYNOPSIS
which [options] [--] programname [...]
DESCRIPTION
Which takes one or more arguments. For each of its argu
ments 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 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 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 match
ing 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.
Print version information on standard output then exit
successfully.
--help
Print usage information on standard output then exit
successfully.
RETURN VALUE
Which returns the number of failed arguments, or -1 when
no `programname´ was given.
EXAMPLE
A useful way to use this utility is by adding an alias for
which like the following:
alias which=´which --tty-only --show-tilde --show-dot´
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
Aliases are also supported, through the use of an alias
for which itself. An example alias for which that is using
this feature is as follows:
alias which=´alias | which --tty-only --read-alias --show-tilde --show-dot´
This will print the output of alias for each alias that
matches one of the given arguments. For example, using
this alias on itself in a tcsh:
$ alias which alias \| /usr/bin/which -i !\*
$ which which
which (alias | /usr/bin/which -i !*)
/usr/bin/which
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 directo
ries to be different when one of them contains a path with
a symbolic link.
AUTHOR
Carlo Wood <carlo@gnu.org>
bash(1)
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