The Skype process seems to be immortal when it crashes in Ubuntu. Killing it with “killall skype” does not work. And it’s not a nice process either, because it uses 100% CPU!
Fortunately, there is a way of killing it without restarting your computer. This is how to do it:
killall skype -s 9
Why does this work? The answer is simple. By adding the arguments “-s 9” the killall command changes the signal type to SIGKILL instead of SIGTERM. Obviously, Skype does not do anything about the SIGTERM signal, and that is why the process stays alive.