I do know there are questions and good answers, what to do if Ubuntu just hangs (like this one: What should I do when Ubuntu freezes?). My problem is that such a hang occurs so seldom for me, that I don't remember most of the answers at that time and I have no second machine to ask the Internet while my main system hangs.
I always remember how to open the console using some Ctrl-Alt-Fx combination. So is there a possibility to have some lines of "intro text" in that console, which tell me directly after switching to the console how to kill hanging processes and how to properly reboot? Think of it as a "reminder to self".
DOS had the ability to change the prompt in a console to arbitrary output. Maybe something similar can be done here to get me remember at least the basics?