You don't need any extra software to map Caps to Esc on X11: Just enable the caps:escape option.
In context: https://github.com/majewsky/system-configuration/blob/6c4478...
In context: https://github.com/majewsky/system-configuration/blob/6c4478...
My xmodmap file has things like:
! Make Caps Lock be Escape and Scroll Lock be Caps Lock
remove Lock = Caps_Lock
keysym Caps_Lock = Escape
remove Lock = Scroll_Lock
keysym Scroll_Lock = Caps_Lock
add Lock = Caps_Lock
After reading this post, I also reverted backspace and bar/backslash: keysym BackSpace = backslash bar
keysym backslash = BackSpace
[1] https://wiki.archlinux.org/index.php/XmodmapEDIT: xmodmap link
ESC if pressed once.
CTRL it pressed with another key.