This is the one software package that I make sure is installed any time I set up a system.
This deceptively simple (it's actually extremely comprehensive) utility gives you the ability to get into your system at any time, as it's text mode. If you ever used Norton Commander in DOS you should feel right at home. As long as you can log in to your system, it doesn't matter if you can't get X running, or your mouse doesn't work, you can fire this up and go to town browsing and editing your files without knowing how to use an editor such as vi. I use it as my standard file browser/editor for everything short of browsing images. It's easy as su to root (if your need is to edit files outside of your home directory that is), type mc and go. No fuss, no muss. Hope this helps somebody