Getting character key code mappings in Ubuntu
Run xev from a terminal. This will give you a new window.
Place your mouse pointer in this window, type some keys and watch for results in the terminal.
In order to get a terminal print-out of all key codes and corresponding keys, run the following command in a terminal:
xmodmap -pk
It's not easy to view in a (small) terminal window, so if you want to save the output to a file, just add the command to let the terminal output be saved in a file (in your current working directory in the terminal):
xmodmap -pk > mykeyboard.txt
Full description of how to use xmodmap here.