Linux is the first truly free Unix-like operating system. The underlying GNU Project was launched in 1983 by Richard Stallman originally to develop a Unix-compatible operating system called GNU, intended to be entirely free software. Many programs and utilities were contributed by developers around the world, and by 1991 most of the components of the system were ready.

A federal court in Utah ruled that Novell Inc., not SCO Group Inc., is the rightful owner of the copyright in the Unix operating system.

The ruling is a boon to the "open source" software movement and to Linux, the freely available computer operating system that has become an alternative to Microsoft Corp.'s Windows operating system.

"A brief review of the history of Unix will place in context much of the terminology and philosophy of this operating system. Terms like Linux, GNU, Unix, Gnome, Free Software, and Free and Open Source Software get bandied around, often with little understanding and usually with much misunderstanding..."

Do you know why Unix failed to take off as a mainstream operating system? It wasn't because it was too hard to use. Mac OS X, the universally acclaimed 'easy' operating system is built on top of BSD Unix. It's certainly not because Windows is better. It wasn't and it isn't. No, I put most of the blame for Unix's failure on its internal wars.

"The GNU operating system is a complete free software system, upward-compatible with Unix. GNU stands for “GNU's Not Unix”. Richard Stallman made the Initial Announcement of the GNU Project in September 1983. A longer version called the GNU Manifesto was published in September 1985 [...] By 1990 we had either found or written all the major components except one—the kernel.

We are very familiar with Linux and its relation with UNIX.But most us of dont actually know what are differnces between the two.
Linux is called Unix-like and is not a true Unix operating system.

What's the big deal about Linux? Isn't it at heart just a PC-based version of UNIX – the ‘70’s hit operating system which has outlived the predictions of its demise throughout the ‘90’s? If you’ve come from a Solaris or HP/UX or AIX background isn’t a PC-based UNIX a bit, well, passé?

Whenever people thinks of a free operating system (if they do), the odds are that they will think of Linux, a clone of UNIX from 1991. They also might think of one or more of the BSDs, UNIX-derivatives dating back to the early ’80s. Let’s face it, though—UNIX is pretty boring. It was great for a PDP-11, and it gets the job done now, but it’s not exactly exciting.

I have said it before and I will say it again. Linux seems to me to be the fastest growing operating system in the history of computing. It has diversified so much that it is running more devices than any single operating system. Even if you are a devout windows, mac, BSD or UNIX advocate I will bet that you will be using a Linux device and not even know it.