Remap key to a UTF character from another keyboard layout in Linux?

This may be different between different distributions, and, typically there may also difference between working in a terminal or with graphical programs.

I use 'key composing' to make unicode characters. This means that one key on the keyboard is assigned the 'compose' character. I can now type, eg. 'Compose', then '1' then '2', and get '½'. This works great for me. There's a large table already defined. To enable it, I defined

keycode 134 = Multi_key

in the file .Xmodmap in my home directory. Look for 'linux compose key' in google for more info. Never needed it, but I'm quite sure you can edit the compose table to add/modify other combinations.

In that same file (.Xmodmap) you can directly assign characters to keys too.