Git

Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency. Git is easy to learn and has a tiny footprint with lightning fast performance. It outclasses SCM tools like Subversion, CVS, Perforce, and ClearCase with features like cheap local branching, convenient staging areas, and multiple workflows.

Git is a version control system (VCS) that is used for software development and other version control tasks. As a distributed revision control system it is aimed at speed, data integrity, and support for distributed, non-linear workflows. Git was created by Linus Torvalds in 2005 for development of the Linux kernel, with other kernel developers contributing to its initial development.

As with most other distributed version control systems, and unlike most client–server systems, every Git directory on every computer is a full-fledged repository with complete history and full version tracking abilities, independent of network access or a central server.

In computer programming, distributed version control, also known as distributed revision control or decentralized version control, allows many software developers to work on a given project without requiring them to share a common network. The software revisions are stored in a distributed revision control system (DRCS), also known as a distributed version control system (DVCS).

Distributed revision control takes a peer-to-peer approach to version control, as opposed to the client-server approach of centralized systems. Rather than a single, central repository on which clients synchronize, each peer's working copy of the codebase is a complete repository. Distributed revision control synchronizes repositories by exchanging patches (sets of changes) from peer to peer. This results in some important differences from a centralized system:

• No canonical, reference copy of the codebase exists by default; only working copies.
• Common operations (such as commits, viewing history, and reverting changes) are fast, because there is no need to communicate with a central server.
• Communication is only necessary when sharing changes among other peers.
• Each working copy effectively functions as a remote backup of the codebase and of its change-history, protecting against data loss.

Why the 'Git' name?
Quoting Linus: "I'm an egotistical bastard, and I name all my projects after myself. First 'Linux', now 'Git'".
('git' is British slang for "pig headed, think they are always correct, argumentative").
Alternatively, in Linus' own words as the inventor of Git: "git" can mean anything, depending on your mood:

• Random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
• Stupid. Contemptible and despicable. Simple. Take your pick from the dictionary of slang.
• "Global information tracker": you're in a good mood, and it actually works for you. Angels sing and light suddenly fills the room.
• "Goddamn idiotic truckload of sh*t": when it breaks