Git

Git is a distributed revision control system available on all mainstream development platforms through a free software license. An important difference of git over its older ancestors is that it elevates the software's revisions to first-class citizens. Developers care deeply about software revisions, and git supports this by giving each developer a complete private copy of the software repository and numerous ways to manage revisions within its context. The ability to associate a local repository with numerous remote ones allows developers and their managers to build a variety of interesting distributed workflows, most of which are impossible to run on a traditional centralized version control system. The local repository also makes git responsive, easy to setup, and able to operate without Internet connectivity. GitHub is a git repository hosting provider that simplifies many repository management tasks through a Web-based user interface while also promoting cooperation in open source projects.