Linux is an operating system kernel developed in the nineties by Linus Torvalds. It is open source, which means it is free to download, use, distribute, edit and even sell with no complicated copyright or licensing issues.
The Linux kernel is the basis for hundreds of "distributions" or fully fledged operating systems, the world over.
Linux runs on millions of desktop computers and servers the world over and is the back-bone of the Internet, nearly all distributions based on Linux are free and every one of the them has an open source concept.
