Git is a most widely used and powerful version control system for tracking changes in computer files and coordinating work on those files among multiple people. It is primarily used for source code management in software development, but it can be used to keep track of changes in any set of files.
Git was developed by Linus Torvalds in 2005 as an distributed open source software version control software and of course it is free to use. As a distributed revision control system it is aimed at speed, data integrity, and support for distributed, non-linear work flows.