.Xmodmap

! this file can only be run once, set a guard to prevent it from being run again
! before changing any modifier they must be removed from their modifier map
remove Control = Control_R
remove Lock = Escape
remove Mod1 = Alt_R

! Map right alt to control
keycode 105 = Alt_R
keycode 108 = Control_R

! Map caps lock to escape
keycode 66 = Escape

! and then add the modifiers back? seems to work
add Mod1 = Alt_R
add Control = Control_R

! Caps_Lock is keycode 66
! Control_R is keycode 105
! Alt_R is keycode 108
! Escape is keycode 9

! When mapping one modifier to another, xmodmap man says you must first unmap it from its original modifier map so it is not in the two different modifier lists
! mod1, lock and control are modifier maps meant for Alt, Caps Lock, and Control modifiers respectively. Run xmodmap to see the maps and which modifiers are bound to them.