iTerm is the muscly old brother of Terminal.app. If you find yourself regularly opening Terminal to use the UNIX command line, you might like the extra features of iTerm — tabs and bookmarks. The tabs are as easy to use as in Safari — you can open them, close them, and switch between them. iTerm’s bookmarks feature is especially helpful. You can save commonly used UNIX commands as “bookmarks” and execute them simply by clicking. Great app for the UNIX user.