Unix celebrates its 40th anniversary this summer. This article from ComputerWorld recounts the history of the world's most productive OS.
Not a week goes by that I'm not somehow reminded of just how powerful Unix is. Treating all devices as files was brilliant. Being able to combine command line utilities via I/O redirection gives an amazing amount of power and flexibility to the Unix/Linux user interface.
It's no wonder the first thing I do whenever presented with a stock Windows PC is to download the Cygwin utilities. I still can't see how anyone can get any work done using only the built-in Windows commands.