I got as far as checkout and then got this error.

mycavesmba11-2:local daveclucas$ git checkout therion
error: pathspec 'therion' did not match any file(s) known to git.

I tried to pull the files again with this result

mycavesmba11-2:local daveclucas$ git pull chris therion
From https://github.com/un1x86/homebrew
 * branch            therion    -> FETCH_HEAD
Already up-to-date.
 

Dave Clucas
daveclucas.com
mycaves.org.
daveclucas@icloud.com