Terminal (also known as the shell) is a place you can run Unix commands under OS X. The shell is very powerful and extremely useful, although it may seem rather daunting to many.

A lot of the little utilities that have been released as Shareware or Freeware are really just running Unix commands that you could actually just run yourself (which might be safer) by typing.

I highly recommend that every Mac user learns the very basics of using the Terminal, even if they can only list a directory, navigate the directory structure, create and delete directories, move or remove files & directories, and modify file permissions.

O'Reilly has an OUTSTANDING beginner book available for $20. www.oreilly.com/catalog/ltigerunix/ The earlier versions for Jaguar and Panther are fine, too.