Git
Git is a free distributed version control system (DVCS), or source code management (SCM) project with an emphasis on being fast. Git was initially designed and created by Linus Torvalds for Linux kernel development. Git operates on a decentralized architecture, so every git working directory is a full-fledged repository with complete history and full revision-tracking capabilities, and is not dependent upon network access or a central server.
Unlike popular non-distributed predecessors such as Subversion and CVS, git only needs a central server for one thing: publishing changes to other users of the central server. You can examine the full development history commit changes on your own computer, and share changes directly with other people, without needing to consult the central server.
Git contrasts also with the monolithic applications Subversion and CVS by its design: it is a typical Unix toolset containing lots of small components that do single atomic tasks. As of Git v1.5.3, the suite of utilities collectively referred to as "git" consists of 143 commands. You do not need to know all of these to use git! Most of them are for specialized use, and a large fraction are intended to be useful inside shell scripts rather than to end users.
