Permanently remap caps lock to escape

[Quake]

I want to permanently remap those two keys it works with xmodmap but it is not permanent. I tried creating an xinitrc file like here but I don't finde the /etc/init.d/gdb file so I couldn't do it that way. How can I do it?

[kubicle]

You can do that with System Settings>Input Devices>Keyboard>Advanced tab>Caps Lock Key Behavior>Swap ESC and Caps Lock