I Never use Escape in Emacs, then why on earth do I ever want to swap Caps Lock with Escape ? Actually, Escape key in Emacs is kind of special. You don't need to hold down the Escape key while using the key bindings starting with ESC , which is very different from Ctrl and Meta . I don't know how Escape key event is generated in Emacs or in X11, but from a user point of view, it is quite like other non-modifier keys. You press it down and release it, one key is generated. This is really nice since we can then use it as the "leader" key for the Emacs just like the Space key in Spacemacs.

So first, let's swap Escape and Caps Lock so we can easily reach Escape by our left pinky. I use setxkbmap :

setxkbmap -option caps:swapescape

Then remap ESC to C-c since it is the standard prefix key reserved for users:

(define-key key-translation-map (kbd "ESC" ) (kbd "C-c" ))

So why is this useful? If you like the way Spacemacs organizes its key bindings, you can replace its key bindings with C-c as the prefix instead of Space , since all the single letter key bindings starting with C-c are reserved for users. Now let's assume that you bind C-c b b to behave like SPC b b , which is helm-mini in the case of Spacemacs. You can press the key bindings in following ways(note ESC has been remapped to C-c and swapped with Caps Lock so you can easily press it by your left pinky):

ESC , b , b , just like SPC , b , b , one keystroke at a time. Holding down ESC and b at the same time and then release ESC and press b , just like how you would press C-x b . Holding down ESC and press b , b , just like how you would press C-x C-x .