I Have to study Unix in my 5th sem. of b.tech. I want to know that Unix is related with Linux. Than which Linux should i use?
i guess you'll be taught about some commands like grep etc so your choice of LINUX distribution shouldn't be a problem..
you can install any flavour of LINUX and you should fine...
Unix is somewhat like a specifications for Open Source and proprietary. Although, one can call -BSD kernels as Unix only and BSD kernels are freely available. Linux on the other hand, is an Open Source Kernel designed for Open Source Unix clone, GNU/Linux.
Regarding which Linux you should use, you have to decide yourself. Tons of Linux distros are freely available to download/install. Basic difference between Linux distros is in Package Management, Graphical Interface ( Desktop Environments, tweaks ) and a few other things. Basic commands are same in all distros. I would suggest you try LiveCDs of as many distros as you can and pick one you like the most.
The primary difference between UNIX and Linux is in the way the kernel is designed. Externally u will find no difference. The same shell, commands, Window Managers, Desktop environment & Utilities are available for both. Internally it is a totally different beast. Process Maanagement, memory management, scheduling are designed and operate differently.
If i were you then which Linux will you prefer to use ?
As I suggested earlier, you should choose yourself. Nobody can tell you which distro is best for you. All Linux distros are same at core and differ in Package Management, GUI and a few other things.
I would suggest you try LiveCDs first.
Ubuntu, OpenSuSe, Mandriva, PCLinuxOS, Fedora... List goes on..... I prefer Debian and CentOS for Servers. Check Distrowatch.com and pick any in Top 10 list.
Actually the guy wanted to learn linux for his 5th sem. So lets help him pick one.
If you want *pure* UNIX, go for OpenSolaris or FreeBSD...
But I know that subject, a Linux distro would be enough...