Linux: Swap CapsLock Escape Keys

How to make CapsLock do Esc Key on Linux?

Create a file at ~/.Xmodmap with the following content:

! 2014年09月10日
! make caps lock do escape
! from http://xahlee.info/
! keycode 9 = Escape NoSymbol Escape
! keycode 66 = Caps_Lock NoSymbol Caps_Lock
clear Lock
keycode 66 = Escape NoSymbol Escape

Now, run this line in terminal:

xmodmap ~/.Xmodmap

When you restart, that file will run automatically.