If you want to list the current keymap table, issue the command: xmodmap -pk | more
The xkeycaps program is a sort of graphical front-end for xmodmap. Start it and see which numbers mean which keycode.
To make the mouse buttons left-handed, use a command: xmodmap -e "pointer = 3 2 1"
To remove the CapsLock and change it to control key, write this in your Xmodmap file:
remove Lock = Caps_Lock keysym Caps_Lock = Control_L add Control = Control_L