Git Lab FAQ

Git Commit Message Editor

If you're seeing something like command not found, then we need to get the editor set up to run from the command line. Issues with the commit message editor are frustrating, but they end up being fairly easy fixes in the end.

Sublime: See this Sublime fix. Run the ln as sudo if it doesn't work for you the first time, e.g., sudo ln ... and then enter the password for your machine. Make sure that you installed Sublime in your Applications folder.
Atom: See the Atom installation page. It's a little buried, but there's a spot that says "To install the atom and apm commands, run ..."
VS Code: See VS Code as Git Editor and set up to be able to call the application from the command line.