What is the relation between UNIX and LINUX?

Does LINUX has anything to do with UNIX?? and is Ubuntu based on Linux or Unix?

What is the relation between UNIX and LINUX?
UNIX" has at least three main branches. However, if you know one type of Unix then you'll recognize the others. They are:





UNIX -- now owned by Novell. This is the original AT%26amp;T / Bell Labs trunk.





Linux -- This was started by Linus Torvalds as a way to teach UNIX. It has the same command structure, etc as UNIX, but runs on a PC. Now this is huge business.





BSD - AT%26amp;T / Bell gave Berkley University a stack of code for academic purposes. This is now called BSD, and this is the stuff that is the basis for much of the current Mac code. While technically not UNIX, it does have a common ancestry, and the commands and structure is very much the same.
Reply:UNIX is based on CUI


and


LINUX is based on GUI
Reply:Unix was an operating system created by Bell Labs/AT%26amp;T back in the late 60s and early 70s. It was a big deal because back then when a company built a computer they had to also create their own operating system specifically for that computer. Unix was written in a programming language called C. C is known as a portable language which means that it can be recompiled with a program called a compiler to run on different computers. Now you could run the same operating system on different computers and thus be able to run the same applications. Imagine if today everyone had their own OS, like Dell-OS, Gateway-OS, HP-OS, etc. Instead we have Windows as a common operating system as well as Linux.





Unix was a very expensive operating system, but it was very powerful. It could support multiple users and had a new philosophy attached to it. That philosophy was, "do one thing, but do it well" which means that a program shouldn't try to do more than its original purpose and to focus on doing that one purpose as well as possible. This made Unix a very stable and secure OS. Eventually Bell Labs (part of AT%26amp;T) licensed the source code out to others. BSD which is the Berkley Software Distribution was licensed to Berkley University in California. Sun Microsystems has Solaris, IBM has AIX, and even Microsoft had their own version known as Xenix, though it never took off.





In 1991, a college student at the University of Helsinki in Finland named Linus Torvalds was amazed by the Unix computers and wanted to run his own personal version. At the time he was using a clone known as Minix. Minix was written from scratch using no original Unix source code but was designed to look and act like Unix. It was written by Andrew Tanenbaum in the 80s as a means of teaching his computer science students how and operating system works. Tanenbaum was actually a professor in Amsterdam and so Torvalds didn't actually know him. Torvalds liked Minix but he thought it was rather basic. It didn't support all of the features he needed so he decided to write his own version. In Unix subculture it is typical for a Unix-like OS to end in 'x' so Linux was named after Linus but with an 'x' at the end.





Linux did not have any original Unix source code but was written to meet Unix specifications so that it would act exactly like Unix. It was basically a clone. Today, Ubuntu as well as many other distributions are based on the Linux kernel which acts like Unix.





These distributions also use a set of programs called the GNU system. GNU stands for GNU is Not Unix. It is a recursive acronym meaning the first G stands for the acronym itself. This project was started in 1985 by Richard Stallman who also wanted to create a Unix clone but wanted to license it as free software. This means that anybody could use the software for free and have access to the source code so they could improve upon it as they like. Unix was only sold in binary form and the average person could not alter the source code to meet their needs. Stallman's goal was to create an entire Unix OS. What happened however was that he managed to create all of the programs he needed (compiler, text editor, programming libraries, etc.) but it took an unusually long time to create the kernel which is the core of the operating system. Torvalds stepped in and was able to create a better kernel than the GNU people were working on but he also used the GNU tools and applications. Because of this, people will often refer to it as GNU/Linux because Linux is the kernel while the GNU system made by Stallman and his fellow programmers contains a lot of crucial applications like the now famous compiler, GCC (GNU C Compiler which later became GNU Compiler Collection after other programming languages were added).





There is also a heated debate against Torvalds and Tanenbaum on operating system design. That is beyond the scope of this question, but I provided a link in the sources if you are interested. Ironic that a CS student and a CS teacher would be fighting so heavily over this. Very interesting read.