Which (Bash)

Use which to find out which version of an executable you're actually running. Quite useful when a given executable might be installed multiple times on a computer.

$ man which

WHICH(1)                                      General Commands Manual                                      WHICH(1)

NAME
       which - locate a command

SYNOPSIS
       which [-a] filename ...

DESCRIPTION
       which  returns the pathnames of the files (or links) which would be executed in the current environment, had
       its arguments been given as commands in a strictly POSIX-conformant shell.  It does this  by  searching  the
       PATH for executable files matching the names of the arguments. It does not canonicalize path names.

OPTIONS
       -a     print all matching pathnames of each argument

EXIT STATUS
       0      if all specified commands are found and executable

       1      if one or more specified commands is nonexistent or not executable

       2      if an invalid option is specified

Debian                                              29 Jun 2016                                            WHICH(1)
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E.g.:

<pre>
$ which wp

/opt/wp