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
SEE ALSO
bash(1)
WHICH(1)