How to Use the which Command in Linux

What which does

which shows the full path of the executable that the shell would run for a command. It searches the folders in your PATH variable in order.

Syntax

which [options] [command]

Example:

which ls

Output: /usr/bin/ls

Options

• -a shows all the matches found in PATH, not only the first.
• --version shows the version of which.
• --help shows a summary of the usage.

Version

which --version

Help

which --help

Examples

Find one command

which grep

Check several commands

which ls pwd cd

cd is a shell built-in, so which may not find a file for it. Use type cd to learn what it is.

Show all matches

which -a python3

Use it in a script

#!/bin/bash
if which curl > /dev/null; then
    echo "curl is installed"
else
    echo "curl is not installed"
fi

command -v curl is a more portable way to do the same check.

which, whereis and type

• which finds the executable in PATH.
• whereis finds the binary, the source and the manual page.
• type tells you if a name is an alias, a built-in, a function or a file.

Quick recap

• which command prints the path of the command. Use which -a to see all matches.