Source material: https://en.wikipedia.org/wiki/Linux
When we say “Linux”, we are referring to the collection of different operating systems based off of the “Linux Kernel”, originally made by this guy in 1991, Linus Torvalds, who now is the lead maintainer of the Linux Kernel, which is the deep system inside of every Linux-based operating system to allow for the operating system to communicate with the hardware.
Initially, the kernel was licensed in a restrictive non-commercial license, but after re-licensing the Kernel under GNU General Public License v2 in 1992, things began to pick up.
Due to the open-ness of the original source code, and the creation of Git, also by Torvalds, to help with version control and development, many more people began to contribute to the base Linux Kernel over the years, and people begun using the Linux Kernel in their operating systems for it’s functionality, and we get to today, where hundreds of different operating systems under hundreds of different companies and communities all use the Linux Kernel, with some operating systems branching off, referred to as “forks” or “distributions”.
Today, you can go online and look at the history of different Linux operating systems, and there is a neat graph at Wikipedia of all the different distributions.
