I'm surprised I had to scroll this far down to find this.

I've been using my own version of 'hyper key'[1] for years now. I map capslock to ctrl (in OSX), then ctrl-space to 'ctrl, command, option' in Karabiner, so that I have a 'namespace' of my own hotkeys, which I assign to apps in apptivate[2] to quick switch, and finally I make it so that if I tap caps without hitting another key, it actually hits escape. I use a two-button combo for hyper instead of just capslock so that capslock on its own is just ctrl, and I can use all the default readline shortcuts.

[1] https://stevelosh.com/blog/2012/10/a-modern-space-cadet/#s14... [2] http://www.apptivateapp.com/

I have been using Karabiner to use vim bindings within OS. CAPS + h/j/k/l... to move up/down... . It's easier than moving your hand to direction keys.