How to use the command 'which' (with examples)

The ‘which’ command is used to locate a program in the user’s path. It is particularly useful when you want to determine the exact location of an executable file.

Use case 1: Search for an executable in the user’s path

Code:

which executable

Motivation: You may want to find the location of an executable file that is already installed on your system or check if a specific program is available.

Explanation: In this use case, the ‘which’ command searches the directories specified in the PATH environment variable and returns the location of the executable if it is found.

Example output:

/usr/bin/executable

Use case 2: Display all locations of matching executables

Code:

which -a executable

Motivation: Sometimes there can be multiple versions of an executable installed on your system. By using the ‘-a’ option, you can view all the locations where matching executables are found.

Explanation: The ‘-a’ option instructs the ‘which’ command to display all matching executables instead of just the first one found.

Example output:

/usr/bin/executable1
/usr/local/bin/executable1

Conclusion:

The ‘which’ command is a handy tool for locating executable files in the user’s path. It allows you to easily find the exact location of a program, which can be helpful when troubleshooting or managing your system. Whether you need to check if a program is installed, find the full path of an executable, or identify potential conflicts with multiple versions, the ‘which’ command has got you covered.