Who Owns This Program?

I’ve got a command docker on my machine. I need to upgrade it. So, who owns it?

This is always a bit of a detective story. The question is type:

$ type -a docker
docker is /usr/local/bin/docker

“If docker was a command, how would you interpret it?” -a means “List all occurrences.” I still don’t know who owns docker.

Next, which:

$ which -a docker
/usr/local/bin/docker

“Locate this program and list all answers.” Nothing new.

Finally, ls -l:

$ ls -l /usr/local/bin/docker
/usr/local/bin/docker -> /Applications/Docker.app/Contents/Resources/bin/docker

“List directory contents of this directory, long format.” Boom. Docker Desktop owns docker. If I want to upgrade it, I have to upgrade Docker Desktop.

Bonus: if you’re using Mac and Homebrew, you can check that too, with brew info <package>. Packages Homebrew knows about will be described, and those that it doesn’t will report “No available formula.”

See man type, man which, and man ls for more info.