In 1994, I wrote the Downhill Project to port Continuus Software’s quarter-million line Continuus/CM configuration management tool suite from UNIX to Windows. After I abandoned it, the project was picked up by AccuRev and renamed “U2NT” and used to port a different CM tool from UNIX to Windows. That I know of, it was also used to move a version of bash and Radius and tiny pieces of it are used in PHP.

Anybody looking to do UNIX-ish things on Windows these days should be using Cygwin.