What is GNU/Linux?

A “Linux” operating system, properly described as GNU/Linux, is an operating system based upon the Linux kernel. The Linux kernel was created by Linus Torvalds initially for his own use during his years in college. It was used with the GNU operating system. GNU, created by Richard Stallman, is the entire operating system, minus the kernel. So, when people say “Linux operating system” they should be saying “GNU/Linux operating system”, or even a “GNU operating system”.

Both Torvalds and Stallman released their software to the world for free.