In Tron, the hacker was not supposed to be snooping around on a network; he was supposed to kill a process. So we went with posix kill and also had him pipe ps into grep. I also ended up using emacs eshell to make the terminal more l33t. The team was delighted to see my emacs performance -- splitting the editor into nested panes and running different modes. I was tickled that I got emacs into a block buster movie. I actually do use emacs irl, and although I do not subscribe to alt.religion.emacs, I think that's all incredibly relevant to the world of Tron.
These images are amazing, but most importantly: