Check out the info on Linux - it's a different type of UNIX - don't think that it's a windows only OS - yes, there are GUIs in it along with most UNIX platforms - but there is also command line. The biggest benefits - you can, if you want, create your own programs, scripts, device drivers, system - it's usually multitasking unlike Windows which did not (I gave up on Bill along time ago - has he changed?). Linux was created only a short time ago.
From
freeos.com
Linux is a Unix clone written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX compliance. It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management and TCP/IP networking.