Thank you all for your helpful replies!
There was no german keyboard layout which allowed me to use the keys I needed
so I went with the proposal of MagicBanana. I wasn't aware of xmodmap and it
really worked, at least for the < > keys. I tried to make 'bar' accessable by
the same key just with AltGr, but by now i didn't succeed. Anyway, I will
figure that one out when i have a bit more time.
I want to add (for other people who have the same problem) that it's of
course neccessary to run
"xmodmap ~/.Xmodmap" at least once after making the changes. But MB was
right: with awesome/i3/xmonad, it's sufficient to run the command one time.
The changes will still persist after reboot.
