Fun idea. Also kudos for using OSX (or rather a Unix shell) as your reference. Although you should introduce the user to how to install cygwin given that Window's what most teens/people are using these days.<p>Why Cygwin (or a Unix shell in general)?<p>Sadly, we're no longer starting win 3.1 via DOS (which was a great way to learn your way around the command line as a child!). On Windows, the built-in CMD these days isn't nearly as powerful as it was (in relation to the rest of the OS) in the past, so having a proper shell around allows for so much more fun (and who wants to do Batch scripting anymore anyway... there're easier tools to automate the specific jobs for you on Windows these days)