Did you ever wonder why pressing an up-arrow in a (Linux) terminal window sometimes recalls the previous command but other times creates ^[[A?

Julia Evans did, and spent months exploring the quirks of the Linux terminal (and writing blog posts describing what she found), finally resulting in The Secret Rules of the Terminal (including the various shells, terminal emulators, escape codes, and TTY driver). A must-read if you’re a newbie who wants to understand why things happen the way they do.