Darcs is a revision control system. Darcs is simple to learn and use, with a powerful new approach to meet the needs of today's distributed software projects. Darcs is decentralized, based on a "theory of patches" with roots in quantum mechanics. Darcs is free software, licensed under the GPL.
Written in Haskell, darcs is used on many operating systems including Linux, MacOS X, FreeBSD, and Windows. Darcs includes a CGI script to browse your repository from the web.