The version control system Linus Torvalds created in 2005 for Linux kernel development was Git.
Torvalds began developing Git on April 3, 2005, after the Linux kernel community lost access to the free-use arrangement for BitKeeper, a proprietary distributed source-control system. He wanted a fast, distributed replacement capable of handling the kernel’s unusually large and collaborative development workflow. Existing free systems did not meet his performance and design requirements.
Git quickly became self-hosting: Torvalds announced it on April 6, and the project was using Git to manage its own development the next day. Its early goals included distributed collaboration, strong protection against repository corruption, and very fast patch handling. Torvalds handed maintenance to Junio Hamano in July 2005, and Git 1.0 was released in December of that year.
Mercurial also emerged from the 2005 BitKeeper dispute, but it was not Torvalds’s project. Git is distributed rather than dependent on one central server, which helped make it suitable for Linux and later made it a standard tool for software projects worldwide.