How to Kill the Caps Lock on your Linux Desktop

Didn’t there used to be a straightforward, GUI-powered way to disable the Caps Lock key on one’s keyboard? I remember it as being one of the first modifications I did as a Linux newbie that actually altered the way a piece of equipment performed (boy, was I proud!). But some time around Ubuntu 11.04 (yes, during the Unity Revolution) that function seems to have vanished. I still use the machinery of Ubuntu, but with the less restrictive Xubuntu as a desktop.