HN, what are your killer Unix tips? I've been using and learning about Unix both at university and at home for almost a year, and I was wondering -- what are the things that, when some wizard showed them to you, you wrote down as soon as you could so you wouldn't forget them? Is there some trick that saves you a buttload of time? Some script that makes your job way easier? Some command that made you smack your forehead in frustration when you found out it could be that simple?Note: I'm personally looking for tips for working in bash (specifically OS X stuff if that makes any difference), but if there's some amazing thing that only works in zsh under Debian or something, feel free to suggest those too -- it's sure to be useful for someone.
I had a quick search for previous topics on this, but all I found was http://news.ycombinator.com/item?id=103725 which had a couple of badass things in the discussion.