Computer literate people know how much secure and powerful UNIX operating system is but we still use windows because it’s more useful to common man. However in times when you have to study UNIX, you have no choice but install some Linux flavor on your PC just for learning UNIX commands and scripts. However as the title of this post says, you can learn UNIX on your Windows system too! Telnet and free UNIX account provider like sdf.lonestar.org makes this possible. All you have to do is type: telnet sdf.lonestar.org in the run box and you will be connected to a UNIX system where you can create free UNIX account. This account remain active for 100 days but if you want it to be forever then you have to pay a tiny fee of 1$ (or 5$ via paypal). This service is best for students who want to learn UNIX without messing up with their existing operating system.