Remembering all those esoteric command names and all the crazy switches when you're messing around with the command line interface underneath Linux can be a pain.
If you're new to the whole thing, but keen to learn your way around the CLI, it can be useful to have a quick cheat sheet around for when you inevitably forget something.
LXpages have a nice command line reference page which you might well be interested in. You can check it out at blog.lxpages.com/ultimate_linux.html.