[dredmorbius]

Or emacs.

The 'set -o <editor>' bit sets the readline editing environment to be similar to vi. It can be set to emacs.

C-xC-e (edit-and-execute-command) invokes the editor specified by $VISUAL, $EDITOR, or emacs, in that order. You could set it to scrivner if you wanted to (though I'm not sure that would necessarily work on exit).

I've tested with VISUAL set to nedit, from which I then changed it to uptime. Now I get loadavg when I want to edit my command line ;-)