When bash encounters an unknown command(word?) it does this : The program 'hello' can be found in the following packages: * hello * hello-debhelper Try: sudo apt-get install <selected package> what I would like to know is how this is done so I can edit it or add something before it to cross check the unknown word from a home grown dictionary which would have phrase:reply pairs that can then be sent to output. I am guilty of not looking enough for it around .. but the few bash guides I tried digging up didn't have anything on this. Maybe I am looking at the wrong places .. any pointers? And yes I am doing this so every time I type wtf when a program fails , I want something nice thrown back at me...