Re: One simple trick...
Yes there are a number of things you can do. Just like Windows a quick ctrl-C will abort a rm operation taking place in an interactive shell. Destroying the window in which the interactive shell running rm is running will work, too (alt-f4 in most window managers or 'x' out of the window)
If you know the process id of the rm process you can 'kill $pid' or do a 'killall -KILL rm'
Couple of problems:
(1) law of maximum perversity says that the most important bits will be destroyed first in any accident sequence
(2) by the time you realize the mistake there is no time to kill rm before law 1 is satisfied
The OP's mad dive for the power button is probably the very best move... provided you are right there at the console. And provided the big red switch is actually connected to anything