In a similar vein to git git git git git, if you’re using jj and find you’ve accidentally typed one jj too many in the command line, it errors at you. In this case we’re trying to pull the id of the current changeset we’re editing: $ jj jj show -T 'change_id.short()' error: unrecognized subcommand 'jj' Usage: jj [OPTIONS] For more information, try '--help'. How annoying. Now we could solve this with a shell alias, but jj also allows us to define alias’ in the configuration (much like git!