I've just installed a fresh Ubuntu. For the last 2 years I've used a system that allowed me to use my Caps Lock key as a keyboard modifier to get the character I want.
For isntance, if I wanted the GBP Pound sterling £ symbol I could type
Caps Lock + - + l and it would output £
If I wanted a German umlaut (ü ö ä Ä Ü ) I could type
Caps Lock + u + : and it would output ü
How is this achieved? (I assume something with xmodmap)