WHICH (1)
show full path of 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).
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 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.
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:
1
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:
4
> 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:
1
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 :
4
$ alias which alias \\| /usr/bin/which -i !\\*
$ which which
which (alias | ./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 directories to be different when one
of them contains a path with a symbolic link.
AUTHOR
Carlo Wood <carlo@gnu.org>
SEE ALSO
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