Linux
Linux relied on software code from MINIX at first. But, with code from the G.N.U. system available for free, he decided it would be good for Linux if it could use that code, instead of code from MINIX, because MINIX did not let people share or change it how they wanted. The G.N.U. General Public License is a software license that lets people change any part of the code they want to, as long as they share any changes they make with the people they give their software to and allow them to redistribute it for free or for a price . The software from G.N.U. was all licensed under the G.N.U. General Public License, so Linus and the other people who worked on Linux could use it.