I constantly hear from other people about how much of the stuff they've used to customize their *nix setup they've shamelessly stolen from other people. So in that spirit, I'd like to start a place to share that stuff here on SO.

Here are the rules:

1. DON'T POST YOUR ENTIRE DOTFILE. Instead, just show us the cool stuff.
2. One recipe per answer
3. You may, however, post multiple versions of your recipe in the same answer. For example, you may post a version that works for bash, a version that works for zsh, and a version that works for csh in the same answer.
4. State what shells you know your recipe will work with in the answer.
5. Let's build this cookbook as a team. If you find out that an answer works with other shells other than the one the author posted, edit it in. If you like an idea and rewrite it to work with another shell, edit the modified version in to the original post.
6. Give credit where credit is due. If you got your idea from someone else, give them credit if possible.

And for those of you (justifiably) asking "Why do we need another one of these threads?":

• Most of what I've seen is along the lines of "post your entire dotfile." Personally, I don't want to try to parse through a person's entire dotfile to figure out what I want. I just want to know about all the cool parts of it.
• It's helpful to have a single dotfile thread. I think most of the stuff that works in bash will work in zsh and it may be adapted to work with csh fairly easily.