I wanted something a bit more comfortable than mv to rename a large number of directories with funny names in them. (No, shell meta-characters wouldn't help, so I couldn't do it programatically.) I built ded, the directory editor, a pretty useful tool for doing just that and a lot more. ded is a vi-like tool to browse through directories, and it allows me to modify file permissions, edit directory entries, etc. The manual is comprehensive, and the tool is worth more than a glance. I won't use it often, but it did come in useful yesterday.