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Source Control Research 

Articles related to source control. 

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Contents 

Articles 

Mercurial 1 

Distributed revision control 5 

Git (software) 9 

BitKeeper 20 

ikiwiki 23 

Subversion (software) 25 

List of revision control software 33 

Comparison of revision control software 36 

Revision control 53 

References 

Article Sources and Contributors 59 

Image Sources, Licenses and Contributors 61 

Article Licenses 

License 62

Mercurial 1 

Mercurial 

Developer(s) Matt Mackall 

Initial release 

Stable release 

April 19, 2005 [1] 

1.6.4 [2] / October 1, 2010 

Written in Python and C 

Operating system Unix-like, Windows, Mac OS X 

Type Revision control 

License GNU GPL 

Website 

mercurial.selenic.com [3] 

Mercurial is a cross-platform, distributed revision control tool for software developers. It is mainly implemented 

using the Python programming language, but includes a binary diff implementation written in C. Mercurial was 

initially written to run on Linux. It has been ported to Windows, Mac OS X, and most Unix-like systems. Mercurial 

is primarily a command line program but graphical user interface extensions are available. All of Mercurial's 

operations are invoked as keyword options to its driver program hg, a reference to the chemical symbol of the 

element mercury. 

Mercurial's major design goals include high performance and scalability, decentralized, fully distributed 

collaborative development, robust handling of both plain text and binary files, and advanced branching and merging 

capabilities, while remaining conceptually simple. [4] It includes an integrated web interface. 

The creator and lead developer of Mercurial is Matt Mackall. Released under the terms of the GNU General Public 

License (version 2 or any later version), Mercurial is free software. 

Technical information 

Mercurial uses SHA-1 hashes to identify revisions. For repository access via a network, Mercurial uses an 

HTTP-based protocol that seeks to reduce round-trip requests, new connections and data transferred. Mercurial can 

also work over ssh where the protocol is very similar to the HTTP-based protocol. 

Documentation 

A comprehensive reference manual, Mercurial: The Definitive Guide, [5] has been written by Bryan O'Sullivan. It is 

available as both a physical book and as a free online reference. The manual is freely available under the terms of the 

Open Publication License.

Mercurial 2 

History 

Mackall first announced Mercurial on April 19, 2005. [1] The impetus for this was the announcement earlier that 

month by Bitmover that they were withdrawing the free version of BitKeeper. 

BitKeeper had been used for the version control requirements of the Linux kernel project. Mackall decided to write a 

distributed version control system as a replacement for use with the Linux kernel. This project started a few days 

after another project called Git, started by Linus Torvalds with similar aims. [6] 

The Linux kernel project decided to use Git rather than Mercurial, but Mercurial is now used by many other projects 

(see below). 

Related software 

• GUI interfaces for Mercurial include: 

Hgk (tcl/tk) 

TortoiseHg 

Murky [8] 

This is implemented as a Mercurial extension, and is part of the 

official version. This viewer displays the directed acyclic graph 

of the changesets of a Mercurial repository. This viewer can be 

invoked via the command 'hg view', if the extension is enabled. 

hgk was originally based on a similar tool for git called gitk. 

There is an hgk replacement named hgview [7] that is written in 

pure python and provides both gtk and qt interfaces. 

Screenshot of hgk in action 

TortoiseHg is a shell extension and a series of applications for the Mercurial distributed revision control 

system. It is available for Windows Explorer and GNOME Nautilus. 

A MacOS X GUI in Objective-C 2.0, runs on Mac OS X 10.5 and later. 

MacMercurial [9] 

MacHg [10] 

A MacOS X GUI '"not intended to completely replace command line use of Mercurial, only to ease the most 

common Mercurial operations," for Mac OS X 10.4 or later. 

MacHg is a free and fast multi-threaded front end for Mac OS X 10.6 and later. 

• Related tools for merging include (h)gct (Qt) and Meld [11] . 

• The convert extension allows import from CVS, Darcs, git, GNU Arch, Monotone, Perforce, Bazaar and 

Subversion repositories. 

• NetBeans supports Mercurial from Version 6. 

• Eclipse supports Mercurial with the MercurialEclipse [12] plugins. 

• HgSccPackage [13] - Mercurial Source Control Plugin for Microsoft Visual Studio 2008/2010 

• VisualHG [14] - Mercurial Source Control Plugin for Microsoft Visual Studio 2005, 2008 and 2010

Mercurial 3 

Adoption 

Source code hosting 

The following websites provide free source code hosting for Mercurial repositories: 

• Bitbucket 

• Google Code [15] 

• Project Kenai by Oracle 

• SourceForge 

• Assembla 

• GNU Savannah 

• Alioth by Debian 

• BerliOS 

• CodePlex [16] 

• Kiln by Fog Creek Software 

• Others listed in the Mercurial wiki [17] 

Projects using Mercurial 

Some projects using the Mercurial distributed RCS: [18] 

• Mozilla [19] 

• OpenJDK [20] 

• OpenSolaris [21] 

• OpenOffice.org [22] 

• Symbian OS [23] 

• The Xen hypervisor [24] 

• Adblock Plus 

• Adium 

• Audacious 

• Coin3D [25] 

• CubicWeb 

• Dovecot IMAP server [26] 

• GeeXboX 

• RabbitMQ 

• Go (programming language) 

• GNU Octave 

• GNU Multi-Precision Library 

• Growl 

• LEMON 

• LinuxTV/Video4Linux 

• LuxRender 3D Render Engine 

• Mercurial 

• MoinMoin wiki software 

• Mutt (email client) 

• Netbeans [27] 

• Nuxeo 

• Ogre3D [28] 

• SAGE

Mercurial 4 

• Vim 

• Lugaru HD [29] 

• Openbravo 

• Tryton 

The developers of the Python programming language have announced that they will transition from Subversion to 

Mercurial. However, as of September 2009 the timeframe is not fixed because the transition team is waiting for 

[30] [31] 

hgsubversion to develop. 

See also 

• Distributed revision control 

• List of revision control software 

• Comparison of revision control software 

References 

[1] Mackall, Matt (2005-04-20). "Mercurial v0.1 - a minimal scalable distributed SCM" (http:/ / www. ussg. iu. edu/ hypermail/ linux/ kernel/ 

0504. 2/ 0670. html). Linux kernel mailing list. . 

[2] Mercurial 1.6.4 - (http:/ / mercurial. selenic. com/ wiki/ WhatsNew#A1. 6. 4_. 282010-10-01. 29) 

[3] http:/ / mercurial. selenic. com/ 

[4] Matt Mackall, Towards a Better SCM: Revlog and Mercurial (http:/ / selenic. com/ mercurial/ wiki/ index. cgi/ 

Presentations?action=AttachFile& do=get& target=ols-mercurial-paper. pdf), Ottawa Linux Symposium Proceedings, 2006. 

[5] Bryan O'Sullivan (2007-01-01). Mercurial: The Definitive Guide (http:/ / hgbook. red-bean. com/ ). . 

[6] Mackall, Matt (2005-04-29). "Re: Mercurial 0.4b vs git patchbomb benchmark" (http:/ / lkml. indiana. edu/ hypermail/ linux/ kernel/ 0504. 3/ 

1404. html). Linux kernel mailing list. . 

[7] http:/ / www. logilab. org/ project/ name/ hgview 

[8] http:/ / bitbucket. org/ snej/ murky/ wiki/ Home 

[9] http:/ / www. jwwalker. com/ pages/ macmerc. html 

[10] http:/ / jasonfharris. com/ machg/ 

[11] http:/ / meld. sourceforge. net/ 

[12] http:/ / www. javaforge. com/ project/ HGE 

[13] http:/ / bitbucket. org/ zzsergant/ hgsccpackage/ 

[14] http:/ / visualhg. codeplex. com/ 

[15] "Google Code Blog: Mercurial Now Available to All Open Source Projects" (http:/ / google-code-updates. blogspot. com/ 2009/ 05/ 

mercurial-now-available-to-all-open. html). 2009-05-28. . 

[16] "CodePlex Weblog: CodePlex now supporting native Mercurial" (http:/ / blogs. msdn. com/ codeplex/ archive/ 2010/ 01/ 22/ 

codeplex-now-supporting-native-mercurial. aspx). 2010-01-22. . 

[17] http:/ / mercurial. selenic. com/ wiki/ MercurialHosting 

[18] Some projects that use Mercurial (http:/ / selenic. com/ mercurial/ wiki/ index. cgi/ ProjectsUsingMercurial) 

[19] J. Paul Reed (2007-04-12). "Version Control System Shootout Redux Redux" (http:/ / weblogs. mozillazine. org/ preed/ 2007/ 04/ 

version_control_system_shootou_1. html). . 

[20] James Gosling. Interview with Robert Eckstein. James Gosling on Open Sourcing Sun's Java Platform Implementations, Part 1 (http:/ / java. 

sun. com/ developer/ technicalArticles/ Interviews/ gosling_os1_qa. html). October 2006. 

[21] "OpenSolaris SCM Project History" (http:/ / opensolaris. org/ os/ community/ tools/ scm/ history/ ). 2006-10-05. . 

[22] "OpenOffice.org development switches to Mercurial" (http:/ / blogs. sun. com/ GullFOSS/ entry/ 

openoffice_org_development_switches_to). 2009-10-15. . 

[23] David Wood (2009-04-06). "We decided in the end to use Mercurial rather than Git." (http:/ / blog. symbian. org/ 2009/ 04/ 06/ 

collaboration-at-the-heart/ #comment-789). . Retrieved 2009-05-07. 

[24] Ian Pratt (2005-07-01). "mercurial now live" (http:/ / lists. xensource. com/ archives/ html/ xen-devel/ 2005-07/ msg00003. html). Xen-devel 

mailing list. . 

[25] "Source code repositories migrated from Subversion to Mercurial" (http:/ / www. coin3d. org/ coin3d_news/ 

source-code-repositories-migrated-from-subversion-to-mercurial). 2010-02-27. . 

[26] Timo Sirainen (2007-05-19). "CVS to Mercurial switch" (http:/ / www. dovecot. org/ list/ dovecot-news/ 2007-May/ 000044. html). 

Dovecot-news mailing list. . 

[27] "Switch to hg.netbeans.org completed" (http:/ / www. netbeans. org/ servlets/ ReadMsg?list=nbdev& msgNo=40342). January 2008. . 

[28] "Mercurial « OGRE – Open Source 3D Graphics Engine" (http:/ / www. ogre3d. org/ developers/ mercurial). 2010-04-04. .

Mercurial 5 

[29] Ryan C. Gordon (2010-05-11). "Lugaru goes open source!" (http:/ / icculus. org/ news/ news. php?id=4590). . 

[30] Guido van Rossum (2009-03-30). "And the winner is..." (http:/ / mail. python. org/ pipermail/ python-dev/ 2009-March/ 087931. html). 

Python-Dev mailing list. . 

[31] Python PEP 385 (http:/ / www. python. org/ dev/ peps/ pep-0385/ #timeline) with Timeline TBD (As of September 2009) 

External links 

• Official Mercurial Project Wiki (http:/ / mercurial. selenic. com/ ) 

• Unofficial Mercurial Home Page (http:/ / hg-scm. org/ ) 

• Mercurial: The Definitive Guide (http:/ / hgbook. red-bean. com/ ) a book by Bryan O'Sullivan published in 2009 

by O'Reilly and freely available online 

• Mercurial: an alternative to git (http:/ / lwn. net/ Articles/ 151624/ ) from LWN.net 

• An example-based Mercurial tutorial (http:/ / jemander. se/ MercurialByExample. pdf) covering both basic and 

advanced use 

• Mercurial for TeamWare users (http:/ / genunix. org/ wiki/ index. php/ Mercurial_for_TeamWare_users) 

• Google TechTalk on Mercurial (http:/ / video. google. com/ videoplay?docid=-7724296011317502612) 

• Subversion or CVS, Bazaar or Mercurial? Four open source version control systems compared (http:/ / javaworld. 

com/ javaworld/ jw-09-2007/ jw-09-versioncontrol. html?page=1) 

• HgEclipse (http:/ / javaforge. com/ project/ HGE) is an open source plugin that supports Mercurial within the 

Eclipse IDE. 

• Joel Spolsky's Mercurial tutorial (http:/ / hginit. com/ ) 

Distributed revision control 

Distributed revision control (or Distributed Version Control (Systems) (DVCS), or Decentralized Version 

Control (Systems)) is a system for software revision control. The system allows individual developers to work on 

code without needing to be connected to a central network. 

Distributed vs. centralized 

Distributed revision control (DRCS) takes a peer-to-peer approach, 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 bona-fide repository. [1] Distributed revision control conducts synchronization by exchanging 

patches (change-sets) 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. [2] 

Rather, communication is only necessary when pushing or pulling changes to or from other peers. 

• Each working copy effectively functions as a remote backup of the codebase and of its change-history, providing 

natural protection against data loss. [2] 

Other differences are as follows: 

• There may be many "central" repositories. 

• Code from disparate repositories are merged based on a web of trust, i.e., historical merit or quality of changes. 

• Lieutenants are project members who have the power to dynamically decide which branches to merge. 

• Network is not involved in most operations. 

• A separate set of "sync" operations are available for committing or receiving changes with remote repositories.


DVCS proponents point to several advantages of distributed version control systems over the traditional centralised 

model: 

• Allows users to work productively even when not connected to a network 

• Makes most operations much faster since no network is involved 

• Allows participation in projects without requiring permissions from project authorities, and thus arguably better 

fosters culture of meritocracy instead of requiring "committer" status 

• Allows private work, so users can use their revision control system even for early drafts they do not want to 

publish 

• Avoids relying on a single physical machine as a single point of failure. 

• Still permits centralized control of the "release version" of the project 

Software development author Joel Spolsky describes distributed version control as "possibly the biggest advance in 

software development technology in the [past] ten years." [3] 

As a disadvantage of DVCS, one could note that initial cloning of a repository is slower compared to centralized 

checkout, because all branches and revision history are copied. This may be relevant if access speed is low and the 

project is large enough. For instance, the size of the cloned git repository (all history, branches, tags, etc.) for the 

Linux kernel is approximately the size of the checked-out uncompressed HEAD, whereas the equivalent checkout of 

a single branch in a centralized checkout would be the compressed size of the contents of HEAD (except without any 

history, branches, tags, etc.). 

Systems 

Open systems 

An "open system" of distributed revision control is characterized by its support for independent branches, and its 

heavy reliance on merge operations. Its general characteristics include: 

• Every working copy is effectively a branch. 

• The system implements each branch as a working copy, with merges conducted by ordinary patch exchange, from 

branch to branch. 

• Code forking therefore occurs more readily, where desired, because every working copy is a potential fork. (By 

the same token, undesirable forks are easier to mend because, if the dispute can be resolved, re-merging the code 

is easy.) 

• It may be possible to "cherry-pick" single changes, selectively pulling them from peer to peer. 

• New peers can freely join, without applying for access to a server. 

One of the first open systems, BitKeeper, served in the development of the Linux kernel. When the makers of 

BitKeeper decided in 2005 to restrict its licensing, [4] Linux developers looked for a free replacement. 

As of 2010, common open systems in free use include: 

• Bazaar, as of 2008 used by Ubuntu [5] and MySQL [6] 

• Darcs 

• Git, created by Linus Torvalds, influenced by BitKeeper and Monotone, aiming at very high performance, 

currently used for the Linux kernel, the GNOME desktop environment, X.org, Perl, DragonFlyBSD and under 

investigation by KDE [7] 

• Mercurial, created with same goals and at about the same time as Git, currently used by the Mozilla project, 

NetBeans, GoogleCode and OpenJDK (as well as other open source Oracle projects) 

• Monotone 

• SVK 

For a full list, see the comparison of revision control software.


Replicated systems 

A replicated system of distributed revision control depends on a replicated database. A check-in is equivalent to a 

distributed commit. Successful commits create a single baseline, which reduces the need for merges. An example of 

a replicated distributed system is Code Co-op. 

Work model 

The distributed model is generally better suited for large projects with partly independent developers, such as the 

Linux kernel project, because developers can work independently and submit their changes for merge (or rejection). 

In the centralized model, developers should serialize their work, or they may have problems with different versions. 

History 

First generation open-source DVCSes include Arch and Monotone. The second generation was initiated by the 

arrival of Darcs, followed by a host of others. Among them, Mercurial and Git were created as potential 

replacements for BitKeeper when it was pulled from free use by the Linux kernel project by its publisher. Bazaar 

followed not long after. 

Before these, closed source DVCSes such as Sun WorkShop TeamWare (which inspired BitKeeper) were widely 

used in enterprise settings. 

Future 

Some natively centralized systems are starting to grow distributed features. For example, Subversion is able to do 

many operations with no network. [8] It may become more difficult to separate natively distributed vs centralized 

systems. 

There are many tools that rely on version control, such as wikis, file systems, and text editors. Some are starting to 

adopt DVCS features, and even integrate with them, for example the Gazest wiki [9] , ikiwiki. 

See also 

• Revision control 



• Category:Software using distributed revision control 

References 

[1] Wheeler, David. "Comments on Open Source Software / Free Software (OSS/FS) Software Configuration Management (SCM) Systems" 

(http:/ / www. dwheeler. com/ essays/ scm. html). . Retrieved May 8, 2007. 

[2] O'Sullivan, Bryan. "Distributed revision control with Mercurial" (http:/ / hgbook. red-bean. com/ hgbook. html). . Retrieved July 13, 2007. 

[3] Spolsky, Joel (2010-03-17). "Distributed Version Control is here to stay, baby" (http:/ / joelonsoftware. com/ items/ 2010/ 03/ 17. html). Joel 

on Software. . Retrieved 2010-06-18. 

[4] "Bitmover ends free Bitkeeper, replacement sought for managing Linux kernel code" (http:/ / en. wikinews. org/ wiki/ 

Bitmover_ends_free_Bitkeeper,_replacement_sought_for_managing_Linux_kernel_code). Wikinews. April 7, 2005. . 

[5] "Ubuntu in Launchpad" (http:/ / launchpad. net/ ubuntu). Canonical Ltd. . Retrieved 2008-10-21. 

[6] Arnö, Kaj (2008-06-19). "Version Control: Thanks, BitKeeper - Welcome, Bazaar" (http:/ / blogs. mysql. com/ kaj/ 2008/ 06/ 19/ 

version-control-thanks-bitkeeper-welcome-bazaar/ ). . Retrieved 2008-06-19. 

[7] "Getting Started/Sources/Amarok Git Tutorial" (http:/ / techbase. kde. org/ Getting_Started/ Sources/ KDE_git-tutorial). KDE TechBase. 

KDE. August 25, 2009. . Retrieved October 9, 2009. "Amarok is now developed in a Git repository instead of SVN. This was done to help get 

into place all the needed infrastructure to convert all of KDE, including documentation." 

[8] http:/ / osdir. com/ Article203. phtml 

[9] http:/ / ygingras. net/ gazest



• Essay on various revision control systems (http:/ / www. dwheeler. com/ essays/ scm. html), especially the section 

"Centralized vs. Decentralized SCM" 

• Linus Torvalds email describing git (DVCS) to KDE developers (http:/ / lwn. net/ Articles/ 246381/ ) 

• Video of a talk Linus Torvalds gave about Git (http:/ / www. youtube. com/ watch?v=4XpnKHJAok8) 

• Bryan O'Sullivan video on Mercurial (http:/ / video. google. com/ videoplay?docid=-7724296011317502612) 

• Ben Collins-Sussman (http:/ / blog. red-bean. com/ sussman/ ?p=20) (one of Subversion's authors) article on "The 

Risks of Distributed Version Control" 

• Distributed Version Control Systems - Why and How (http:/ / people. ubuntu. com/ ~ianc/ papers/ 

dvcs-why-and-how. xhtml) by Ian Clatworthy, Bazaar/Canonical 

• Software Development and Version Control systems (http:/ / www. scribd. com/ doc/ 19815002/ 

Version-Control-Systems-Emphasis-on-distributed-Bzr-Hg-Git) plus handouts (http:/ / www. scribd. com/ doc/ 

19815427/ Version-Control-Systems-Emphasis-on-distributed-Bzr-Hg-Git-Handouts). Emphasis on Distributed 

Version Control Systems (DVCS) by Jari Aalto 

• Introduction to distributed version control systems (http:/ / www. ibm. com/ developerworks/ aix/ library/ 

au-dist_ver_control) - IBM Developer Works article


Git (software) 

Original author(s) Linus Torvalds 

Developer(s) Junio Hamano, Linus Torvalds 


Preview release 

Written in 

Operating system POSIX 

1.7.3.1 [1] (September 29, 2010) [2] [ +/− [1] 

] 

1.7.3.rc2 [3] (September 15, 2010) [4] [ +/− [5] 

] 

C, Bourne Shell, Perl [6] 


License GNU General Public License v2 

Website http:/ / git-scm. com/ 

Git is a distributed revision control system with an emphasis on speed. Git was initially designed and developed by 

Linus Torvalds for Linux kernel development. 

Every Git working directory is a full-fledged repository with complete history and full revision tracking capabilities, 

not dependent on network access or a central server. 

Git's current software maintenance is overseen by Junio Hamano. Git is free software distributed under the terms of 

the GNU General Public License version 2. 

Name 

Linus Torvalds has quipped about the name "git", which is British English slang for a stupid or unpleasant person: [7] 

[8] [9] 

"I'm an egotistical [sic] bastard, and I name all my projects after myself. First Linux, now git." 

The official Git wiki also gives a number of alternative explanations and backronyms for the name, including 

"Global Information Tracker". [8] 

Early history 

Git development began after many Linux kernel developers chose to give up access to the proprietary BitKeeper 

system. [10] The ability to use BitKeeper free of charge had been withdrawn by the copyright holder Larry McVoy 

after he claimed Andrew Tridgell had reverse engineered the BitKeeper protocols. Some alleged that Tridgell 

violated the BitKeeper license, but at Linux.Conf.Au 2005, Tridgell demonstrated during his keynote that the reverse 

engineering process he had used was simply to telnet to the appropriate port of a BitKeeper server and type 

"help". [11] 

Torvalds wanted a distributed system that he could use like BitKeeper, but none of the available free systems met his 

needs, particularly his performance needs. From an e-mail he wrote on April 7, 2005 while writing the first 

prototype: [12]


However, the SCMs I've looked at make this hard. One of the things (the main thing, in fact) I've been 

working at is to make that process really efficient. If it takes half a minute to apply a patch and remember the 

changeset boundary etc. (and quite frankly, that's fast for most SCMs around for a project the size of Linux), 

then a series of 250 emails (which is not unheard of at all when I sync with Andrew, for example) takes two 

hours. If one of the patches in the middle doesn't apply, things are bad bad bad. 

Now, BK wasn't a speed demon either (actually, compared to everything else, BK is a speed deamon [sic], 

often by one or two orders of magnitude), and took about 10–15 seconds per email when I merged with 

Andrew. HOWEVER, with BK that wasn't as big of an issue, since the BKBK merges were so easy, so I 

never had the slow email merges with any of the other main developers. So a patch-application-based SCM 

"merger" actually would need to be faster than BK is. Which is really really really hard. 

So I'm writing some scripts to try to track things a whole lot faster. Initial indications are that I should be able 

to do it almost as quickly as I can just apply the patch, but quite frankly, I'm at most half done, and if I hit a 

snag maybe that's not true at all. Anyway, the reason I can do it quickly is that my scripts will not be an SCM, 

they'll be a very specific "log Linus' state" kind of thing. That will make the linear patch merge a lot more 

time-efficient, and thus possible. 

(If a patch apply takes three seconds, even a big series of patches is not a problem: if I get notified within a 

minute or two that it failed half-way, that's fine, I can then just fix it up manually. That's why latency is 

critical—if I'd have to do things effectively "offline", I'd by definition not be able to fix it up when problems 

happen). 

Torvalds had several design criteria: 

1. Take CVS as an example of what not to do; if in doubt, make the exact opposite decision. To quote Torvalds, 

speaking somewhat tongue-in-cheek: 

"For the first 10 years of kernel maintenance, we literally used tarballs and patches, which is a much superior 

source control management system than CVS is, but I did end up using CVS for 7 years at a commercial 

company [Transmeta [13] ] and I hate it with a passion. When I say I hate CVS with a passion, I have to also say 

that if there are any SVN (Subversion) users in the audience, you might want to leave. Because my hatred of 

CVS has meant that I see Subversion as being the most pointless project ever started. The slogan of 

Subversion for a while was "CVS done right", or something like that, and if you start with that kind of slogan, 

there's nowhere you can go. There is no way to do CVS right." [14] 

2. Support a distributed, BitKeeper-like workflow 

"BitKeeper was not only the first source control system that I ever felt was worth using at all, it was also the 

source control system that taught me why there's a point to them, and how you actually can do things. So Git 

in many ways, even though from a technical angle it is very very different from BitKeeper (which was another 

design goal, because I wanted to make it clear that it wasn't a BitKeeper clone), a lot of the flows we use with 

Git come directly from the flows we learned from BitKeeper." [14] 

[14] [15] 

3. Very strong safeguards against corruption, either accidental or malicious 

4. Very high performance 

The first three criteria eliminated every pre-existing version control system except for Monotone, and the fourth 

excluded everything. [14] So, immediately after the 2.6.12-rc2 Linux kernel development release, [14] he set out to 

write his own. [14] 

The development of Git began on April 3, 2005. [16] The project was announced on April 6, [17] and became 

self-hosting as of April 7. [16] The first merge of multiple branches was done on April 18. [18] Torvalds achieved his 

performance goals; on April 29, the nascent Git was benchmarked recording patches to the Linux kernel tree at the 

rate of 6.7 per second. [19] On June 16, the kernel 2.6.12 release was managed by Git. [20]


While strongly influenced by BitKeeper, Torvalds deliberately attempted to avoid conventional approaches, leading 

to a unique design. [21] He developed the system until it was usable by technical users, then turned over maintenance 

on July 26, 2005 to Junio Hamano, a major contributor to the project. [22] Hamano was responsible for the 1.0 release 

on December 21, 2005, [23] and remains the project's maintainer. 

Design 

Git's design was inspired by BitKeeper and Monotone. [24] [25] Git was originally designed as a low-level version 

control system engine on top of which others could write front ends, such as Cogito or StGIT. [25] However, the core 

Git project has since become a complete revision control system that is usable directly. [26] 

Characteristics 

Git's design is a synthesis of Torvalds's experience with Linux in maintaining a large distributed development 

project, along with his intimate knowledge of file system performance gained from the same project and the urgent 

need to produce a working system in short order. These influences led to the following implementation choices: 

Strong support for non-linear development 

Git supports rapid branching and merging, and includes specific tools for visualizing and navigating a 

non-linear development history. A core assumption in Git is that a change will be merged more often than it is 

written, as it is passed around various reviewers. 

Distributed development 

Like Darcs, BitKeeper, Mercurial, SVK, Bazaar and Monotone, Git gives each developer a local copy of the 

entire development history, and changes are copied from one such repository to another. These changes are 

imported as additional development branches, and can be merged in the same way as a locally developed 

branch. 

Compatibility with existing systems/protocols 

Repositories can be published via HTTP, FTP, rsync, or a Git protocol over either a plain socket or ssh. Git 

also has a CVS server emulation, which enables the use of existing CVS clients and IDE plugins to access Git 

repositories. Subversion and svk repositories can be used directly with git-svn. 

Efficient handling of large projects 

Torvalds has described Git as being very fast and scalable, [27] and performance tests done by Mozilla showed 

it was an order of magnitude faster than some revision control systems, and fetching revision history from 

[28] [29] 

locally stored repository can be two orders of magnitude faster than fetching it from the remote server. 

In particular, Git does not get slower as the project history grows larger. [30] 

Cryptographic authentication of history 

The Git history is stored in such a way that the name of a particular revision (a "commit" in Git terms) depends 

upon the complete development history leading up to that commit. Once it is published, it is not possible to 

change the old versions without it being noticed. The structure is similar to a hash tree, but with additional data 

at the nodes as well as the leaves. [31] (Mercurial and Monotone also have this property.) 

Toolkit-based design 

Git was designed as a set of programs written in C, and a number of shell scripts that provide wrappers around 

those programs. [32] Although most of those scripts have been rewritten in C as part of an ongoing effort to port 

it to Microsoft Windows, the design remains, and it is easy to chain the components together. [33] 

Pluggable merge strategies 

As part of its toolkit design, Git has a well-defined model of an incomplete merge, and it has multiple 

algorithms for completing it, culminating in telling the user that it is unable to complete the merge


automatically and manual editing is required. 

Garbage accumulates unless collected 

Aborting operations or backing out changes will leave useless dangling objects in the database. These are 

generally a small fraction of the continuously growing history of wanted objects, but reclaiming the space 

using git gc --prune can be slow. [34] 

Periodic explicit object packing 

Git stores each newly created object as a separate file. Although individually compressed, this takes a great 

deal of space and is inefficient. This is solved by the use of "packs" that store a large number of objects in a 

single file (or network byte stream), delta-compressed among themselves. Packs are compressed using the 

heuristic that files with the same name are probably similar, but do not depend on it for correctness. Newly 

created objects (newly added history) are still stored singly, and periodic repacking is required to maintain 

space efficiency. Git does periodic repacking automatically but manual repacking is also possible with the 

git gc command. 

Another property of Git is that it snapshots directory trees of files. The earliest systems for tracking versions of 

source code, SCCS and RCS, worked on individual files and emphasized the space savings to be gained from 

interleaved deltas (SCCS) or delta encoding (RCS) the (mostly similar) versions. Later revision control systems 

maintained this notion of a file having an identity across multiple revisions of a project. However, Torvalds rejected 

this concept. [35] Consequently, Git does not explicitly record file revision relationships at any level below the source 

code tree. 

Inexplicit revision relationships has some significant consequences: 

• It is slightly more expensive to examine the change history of a single file than the whole project. [36] To obtain a 

history of changes affecting a given file, Git must walk the global history and then determine whether each 

change modified that file. This method of examining history does, however, let Git produce with equal efficiency 

a single history showing the changes to an arbitrary set of files. For example, a subdirectory of the source tree 

plus an associated global header file is a very common case. 

• Renames are handled implicitly rather than explicitly. A common complaint with CVS is that it uses the name of 

a file to identify its revision history, so moving or renaming a file is not possible without either interrupting its 

history, or renaming the history and thereby making the history inaccurate. Most post-CVS revision control 

systems solve this by giving a file a unique long-lived name (a sort of inode number) that survives renaming. Git 

does not record such an identifier, and this is claimed as an advantage. [37] [38] Source code files are sometimes 

split or merged as well as simply renamed, [39] and recording this as a simple rename would freeze an inaccurate 

description of what happened in the (immutable) history. Git addresses the issue by detecting renames while 

browsing the history of snapshots rather than recording it when making the snapshot. [40] (Briefly, given a file in 

revision N, a file of the same name in revision N−1 is its default ancestor. However, when there is no like-named 

file in revision N−1, Git searches for a file that existed only in revision N−1 and is very similar to the new file.) 

However, it does require more CPU-intensive work every time history is reviewed, and a number of options to 

adjust the heuristics. 

Git implements several merging strategies; a non-default can be selected at merge time: [41] 

• resolve: the traditional three-way merge algorithm. 

• recursive: This is the default when pulling or merging one branch, and is a variant of the three-way merge 

algorithm. "When there are more than one common ancestors that can be used for three-way merge, it creates a 

merged tree of the common ancestors and uses that as the reference tree for the three-way merge. This has been 

reported to result in fewer merge conflicts without causing mis-merges by tests done on actual merge commits 

taken from Linux 2.6 kernel development history. Additionally this can detect and handle merges involving 

renames." [42]


• octopus: This is the default when merging more than two heads. 

Implementation 

Like BitKeeper, Git does not use a centralized server. However, Git's primitives are not inherently a SCM system. 

Torvalds explains, [43] 

In many ways you can just see git as a filesystem — it's content-addressable, and it has a notion of versioning, 

but I really really designed it coming at the problem from the viewpoint of a filesystem person (hey, kernels is 

what I do), and I actually have absolutely zero interest in creating a traditional SCM system. 

In spite of his intentions, Git now has the full set of features expected of a traditional SCM. [44] 

Git has two data structures: a mutable index that caches information about the working directory and the next 

revision to be committed; and an immutable, append-only object database. 

The object database contains four types of objects: 

• A blob object is the content of a file. Blob objects have no filename, timestamps, or other metadata. 

• A tree object is the equivalent of a directory. It contains a list of filenames, each with some type bits and the name 

of a blob or tree object that is that file, symbolic link, or directory's contents. This object describes a snapshot of 

the source tree. 

• A commit object links tree objects together into a history. It contains the name of a tree object (of the top-level 

source directory), a timestamp, a log message, and the names of zero or more parent commit objects. 

• A tag object is a container that contains reference to another object and can hold additional meta-data related to 

another object. Most commonly, it is used to store a digital signature of a commit object corresponding to a 

particular release of the data being tracked by Git. 

The index serves as connection point between the object database and the working tree. 

Each object is identified by a SHA-1 hash of its contents. Git computes the hash, and uses this value for the object's 

name. The object is put into a directory matching the first two characters of its hash. The rest of the hash is used as 

the file name for that object. 

Git stores each revision of a file as a unique blob object. The relationships between the blobs can be found through 

examining the tree and commit objects. Newly added objects are stored in their entirety using zlib compression. This 

can consume a large amount of hard disk space quickly, so objects can be combined into packs, which use delta 

compression to save space, storing blobs as their changes relative to other blobs. 

Git servers typically listen on TCP/IP port 9418. [45] 

Portability 

Git is primarily developed on Linux, but can be used on other Unix-like operating systems including BSD, Solaris 

and Darwin. Git is extremely fast on POSIX-based systems such as Linux. [46] 

Git also runs on Microsoft Windows. There are two variants: 

• A native Microsoft Windows port, called msysgit [47] (using MSYS from MinGW). While somewhat slower than 

the Linux version, [48] it is acceptably fast [49] and is reported to be usable in production, with only minor 

awkwardness. [50] In particular, some commands are not yet available from the GUIs, and must be invoked from 

the command line. 

• Git also runs on top of Cygwin (a POSIX emulation layer), [51] although it is noticeably slower, especially for 

commands written as shell scripts. [52] This is primarily due to the high cost of the fork emulation performed by 

Cygwin. However, the recent rewriting of many Git commands (originally implemented as shell scripts) in C has 

resulted in significant speed improvements on Windows. [53] 

Other alternatives for running Git include:


• git-cvsserver (which emulates a CVS server, allowing use of Windows CVS clients): [54] 

• Eclipse IDE-based Git client, based on a pure Java implementation of Git's internals: egit [55] 

• NetBeans IDE support for Git is under development [56] and is also available via the NbGit [57] plugin 

• The TortoiseGit, Git-Cheetah [58] and Git Extensions [59] are Windows Explorer extension clients, as well as a 

standalone GUI and a Visual Studio 2008 Plug-in. The Git Source Control Provider [60] is another open source 

Visual Studio plug-in that displays project file status of Git in the solution explorer. 

• IntelliJ IDEA Version 8.1 now supports Git through a bundled plugin: Intellij Version Control Systems 

Integration [61] 

• Xcode 4 - as of version 4 preview, git is available as part of the IDE [62] 

• Git# (GitSharp) [63] is a .Net/Mono implementation of git. 

Refactoring the lowest-level Git operations into libraries would theoretically enable re-implementation of the 

higher-level components for Windows without rewriting the rest. [64] 

Adoption 

Source code hosting 

The following websites provide free source code hosting for Git repositories: [65] 

• BerliOS 

• GitHub 

• Gitorious 

• Sourceforge 

• GNU Savannah 

Projects using Git 

A number of high-profile software projects now use Git for revision control: [66] 

[67] [68] 

• Amarok 

• Android [69] 

• Arch Linux 

• Aquamacs Emacs 

• BlueZ [70] 

• Btrfs [71] 

• Citadel [72] 

• Clojure [73] 

• CakePHP [74] 

• cURL [75] 

• Debian [76] 

• Digg [77] 

• DragonFly BSD [78] 

• Eclipse [79] 

• Elinks [80] 

• Fedora 

• FFmpeg [81] 

• Freenet [82] 

• FreeSWITCH [83] 

• git [84] 

• GIMP [85]


[86] [87] 

• GNOME 

• GPM [88] 

• GStreamer [89] 

• gThumb [90] 

• GTK+ [91] 

• Hurd [92] 

• jQuery [93] 

• Kate [94] 

• KDevelop [95] 

• Konversation [96] 

• Laika (EHR testing framework) [97] 

• LilyPond (music typesetting) [98] 

• Linux kernel 

[99] [100] 

• Linux Mint 

• LMMS [101] 

• Marble [102] 

• MeeGo [103] 

• Merb [104] 

• MicroEMACS 

[105] [106] 

• Mono 

• MooTools [107] 

• One Laptop Per Child (OLPC) [108] 

• OpenFOAM [109] 

• openSUSE [110] 

[111] [112] 

• Penumbra: Overture 

• Perl [113] 

• Phonon [114] 

• phpBB [115] 

• Prototype.js [116] 

• Qt [117] 

• Reddit [118] 

• rsync [119] 

• Ruby on Rails [120] 

• Samba [121] 

• SproutCore [122] 

• Starlink [123] 

• Sugar [124] 

• SWI-Prolog [125] 

• Trilinos 

• VLC [126] 

• VTK [127] 

• Wine [128] 

• Xfce [129] 

• Xiph [130] 

• X.org Server [131] 

• x264 [126] 

• YUI [132]


• Zend Framework [133] 

The KDE project has begun migrating to Git, with Amarok [134] [135] and Phonon [136] having completed its migration. 

The Drupal community has recently announced plans to migrate development to Git. [137] 

See also 




• Comparison of open source software hosting facilities 

• Repo (Script) 

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[109] http:/ / www. openfoam. com/ download/ git. php 

[110] openSUSE - Gitorious (http:/ / gitorious. org/ opensuse) 

[111] "FrictionalGames' PenumbraOverture at master" (http:/ / github. com/ FrictionalGames/ PenumbraOverture). GitHub. . 

[112] "Penumbra: Overture goes Open Source!" (http:/ / frictionalgames. blogspot. com/ 2010/ 05/ penumbra-overture-goes-open-source. html). 

Frictional Games. . 

[113] Léon Brocard. "Mailing List Announcement" (http:/ / www. nntp. perl. org/ group/ perl. perl5. porters/ 2008/ 12/ msg142823. html). . 

Retrieved 2008-12-22. "The Perl Foundation has migrated Perl 5 to the Git version control system..." 

[114] Phonon - Gitorious (http:/ / gitorious. org/ phonon) 

[115] phpBB (2010-03-07). "phpBB moves source code versioning from Subversion to Git" (http:/ / www. phpbb. com/ community/ viewtopic. 

php?f=14& t=2015905). phpBB Group. . Retrieved 2010-03-07. 

[116] Prototype JavaScript framework: Contribute (http:/ / prototypejs. org/ contribute) 

[117] "Qt now open for community contributions" (http:/ / www. qtsoftware. com/ about/ news/ qt-contribution-model-announced). 2009-05-11. . 


[118] "Reddit Goes Open Source" (http:/ / blog. reddit. com/ 2008/ 06/ reddit-goes-open-source. html). . Retrieved 2010-02-26.


[119] http:/ / gitweb. samba. org/ ?p=rsync. git 

[120] "Rails is moving from SVN to Git" (http:/ / weblog. rubyonrails. org/ 2008/ 4/ 2/ rails-is-moving-from-svn-to-git). . Retrieved 2008-04-03. 

[121] Using Git for Samba Development - SambaWiki (http:/ / wiki. samba. org/ index. php/ Using_Git_for_Samba_Development) 

[122] SproutCore Documentation (http:/ / www. sproutcore. com/ documentation/ hacking/ ) 

[123] (http:/ / www. starlink. ac. uk) 

[124] Sugar Labs project hosting (http:/ / git. sugarlabs. org/ ) 

[125] Accessing SWI-Prolog source via GIT (http:/ / www. swi-prolog. org/ git. html) 

[126] Git - VideoLAN Wiki (http:/ / wiki. videolan. org/ Git) 

[127] http:/ / vtk. org/ gitweb 

[128] GitWine - The Official Wine Wiki (http:/ / wiki. winehq. org/ GitWine) 

[129] Xfce Git (http:/ / git. xfce. org/ ) 

[130] Xiph Git (http:/ / git. xiph. org/ ) 

[131] X.Org Wiki - Development/git (http:/ / www. x. org/ wiki/ Development/ git) 

[132] "YUI 2 and YUI 3 Source Code Now on GitHub" (http:/ / yuiblog. com/ blog/ 2009/ 01/ 14/ github/ ). . Retrieved 2009-01-20. 

[133] http:/ / git. zendframework. com/ ?a=summary& p=zf 

[134] life at the end of the universe » we’re testing the water for everyone (http:/ / blog. lydiapintscher. de/ 2009/ 07/ 20/ 

were-testing-the-water-for-everyone/ ) 

[135] KDE gets millionth commit - The H Open Source: News and Features (http:/ / www. h-online. com/ open/ KDE-gets-millionth-commit--/ 

news/ 113807) 

[136] Phonon - Gitorious (http:/ / gitorious. org/ phonon) 

[137] Migrating Drupal.org to Git (http:/ / drupal. org/ community-initiatives/ git) 


• Git Homepage (http:/ / git-scm. com) 

• An introduction to git-svn for Subversion/SVK users and deserters (http:/ / utsl. gen. nz/ talks/ git-svn/ intro. 

html), article by Sam Vilain 

• Easy Git (http:/ / www. gnome. org/ ~newren/ eg/ ) - a wrapper script for Git, presenting a simplified user 

interface, designed to be more accessible to users of other revision control systems. 

• git by example (http:/ / sysmonblog. co. uk/ misc/ git_by_example/ ) - simple walk through of common git 

commands 

• Git for computer scientists (http:/ / eagain. net/ articles/ git-for-computer-scientists/ ) - explains how Git 

conceptually works 

• Gittin Down to the Plumbing (http:/ / git-plumbing-preso. heroku. com/ ) - a nice presentation explains Git 

internals by many animations 

• Git for Subversion users (http:/ / pointbeing. net/ weblog/ 2009/ 09/ git-for-subversion-users. html) 

• Git Magic (http:/ / www-cs-students. stanford. edu/ ~blynn/ gitmagic/ ) - a comprehensive listing of Git tips & 

tricks, popularly referred to as "magic". Describes some of the lesser known features of Git. 

• Why Git is Better Than X (http:/ / whygitisbetterthanx. com/ ) - evangelist site comparing Git to Mercurial, 

Bazaar, Subversion and Perforce 

• Git Quick Reference (http:/ / jonas. nitro. dk/ git/ quick-reference. html) 

• All about Git on one page (http:/ / www. markus-gattol. name/ ws/ scm. html) - a page covering Git, starting with 

theory and ending with many practical examples about its usage. 

• Google Tech Talk - Linus Torvalds on Git (http:/ / www. youtube. com/ watch?v=4XpnKHJAok8)

BitKeeper 20 

BitKeeper 

Original author(s) BitMover Inc. 

Operating system AIX, FreeBSD, HP-UX, IRIX, Linux, Mac OS X, NetBSD, OpenBSD, Solaris, Windows 

Type Distributed revision control 

License Proprietary 

Website http:/ / www. bitkeeper. com/ 

BitKeeper is a software tool for distributed revision control (configuration management, SCM, etc.) of computer 

source code. A distributed system, BitKeeper competes largely against other systems such as Git and Mercurial. 

BitKeeper is produced by BitMover Inc., a privately held company based in Campbell, California [1] and owned by 

CEO Larry McVoy, who had previously designed TeamWare. 

BitKeeper builds upon many of the TeamWare concepts. Its key selling point is the fact that it is a distributed 

version control tool, as opposed to CVS or SVN. One of the defining characteristics of any distributed version 

control tool is the ease with which distributed development teams can keep their own local source repositories and 

still work with the central repository. Its web site claims that "BitKeeper has been shown to double the pace of 

software development". 

BitKeeper is proprietary software and is normally sold or leased (as part of a support package) to medium or large 

corporations. [2] 

History 

BitMover used to provide access to the system for certain open source or free software projects, the most famous 

(and controversial) of which was the source code of the Linux kernel. The license for the "community" version of 

BitKeeper had allowed for developers to use the tool at no cost for open source or free software projects, provided 

those developers did not participate in the development of a competing tool (such as CVS, GNU Arch, Subversion or 

ClearCase) for the duration of their usage of BitKeeper plus one year. This restriction applied regardless of whether 

the competing tool is open/free or proprietary. This version of BitKeeper also required that certain meta-information 

about changes be stored on computer servers operated by BitMover (www.openlogging.org [3] ), an addition that 

makes it impossible for community version users to run projects of which BitMover is unaware. 

License concerns 

The decision made in 2002 to use BitKeeper for Linux kernel development was a controversial one. Some, notably 

GNU Project founder Richard Stallman, expressed concern about proprietary tools being used on a flagship free 

project. While project leader Linus Torvalds and other core developers adopted BitKeeper, several key developers 

(including Linux veteran Alan Cox) refused to do so, citing the Bitmover license, and voicing concern that the 

project was ceding some control to a proprietary developer. To mitigate these concerns, BitMover added gateways 

which allowed limited interoperation between the Linux BitKeeper servers (maintained by Bitmover) and developers 

using CVS and Subversion. Even after this addition, flamewars [4] occasionally broke out on the Linux kernel mailing 

list, often involving key kernel developers and BitMover CEO Larry McVoy, who is also a Linux developer.

BitKeeper 21 

Pricing change 

In April 2005, BitMover announced that it would stop providing a version of BitKeeper free of charge to the 

community, giving as the reason the efforts of Andrew "Tridge" Tridgell, a developer employed by OSDL on an 

unrelated project, to develop a client which would show the metadata (data about revisions, possibly including 

differences between versions) instead of only the most recent version. Being able to see metadata and compare past 

versions is one of the core features of all version-control systems but was not available to anyone without a 

commercial BitKeeper license, significantly inconveniencing most Linux kernel developers. Although BitMover 

decided to provide free commercial BitKeeper licenses to some kernel developers, it refused to give or sell licenses 

to anyone employed by OSDL, including Linus Torvalds and Andrew Morton, placing OSDL developers in the same 

position other kernel developers were in. The Git project was launched with the intent of becoming the Linux 

kernel's source code management software, and was eventually adopted by Linux developers. 

End of support for the "Free Use" version was officially July 1, 2005 and users were required to switch to the 

commercial version or change version control system by then. Commercial users are also required not to produce 

any competing tools: in October 2005, McVoy contacted a customer using commercially licensed BitKeeper 

demanding that an employee of the customer stop contributing to the Mercurial project, a GPL source management 

tool. Bryan O'Sullivan, the employee, responded, "To avoid any possible perception of conflict, I have volunteered 

to Larry that as long as I continue to use the commercial version of BitKeeper, I will not contribute to the 

development of Mercurial." [5] 

See also 

• Git 

• Mercurial 



References 

[1] http:/ / www. bitkeeper. com/ Company. html BitMover company information 

[2] http:/ / www. bitkeeper. com/ Sales. How. html BitKeeper sales information 

[3] http:/ / www. openlogging. org 

[4] Stallman, Richard (13 October 2002). "Bitkeeper outragem [sic], old and new" (http:/ / www. uwsg. iu. edu/ hypermail/ linux/ kernel/ 0210. 

1/ 1767. html). linux-kernel mailing list. . Retrieved 8 April 2008. 

[5] O'Sullivan, Bryan (30 September 2005). "Why I am no longer working on Mercurial" (http:/ / article. gmane. org/ gmane. comp. 

version-control. mercurial. devel/ 3481). mercurial-devel mailing list. . Retrieved 14 April 2007. 


• BitKeeper homepage (http:/ / www. bitkeeper. com/ ) 

• BitKeeper's note about the Nov 2003 security breach (http:/ / www. bitkeeper. com/ press/ 2003-11-10-0001. 

html) 

• "Not quite Open Source" (http:/ / lwn. net/ 1999/ features/ BitKeeper. php3) Article on Linux Weekly News, circa 

1999, discussing features, licensing, Larry McVoy, and OSI. 

• "No More Free BitKeeper" (http:/ / kerneltrap. org/ node/ 4966) Discusses BitMover's decision to phase out the 

free version of BitKeeper 

• "BitKeeper and Linux: The end of the road?" (http:/ / www. linux. com/ articles/ 44147) discusses the BitKeeper 

fiasco from three viewpoints: Linus Torvalds, Larry McVoy, Andrew "Tridge" Tridgell (the alleged 

reverse-engineer who offers a short explanation of the situation)

BitKeeper 22 

• How Tridge reverse-engineered Bitkeeper (http:/ / lwn. net/ Articles/ 132938/ ) and Torvalds knifes Tridgell 

(http:/ / www. theregister. co. uk/ 2005/ 04/ 14/ torvalds_attacks_tridgell/ ), two articles describing Tridgell's 2005 

linux.conf.au keynote and comparing what he did to statements by Torvalds and McVoy 

• SourcePuller (http:/ / sourceforge. net/ projects/ sourcepuller/ ) is the result of Tridgell's efforts 

• RMS: BitKeeper bon-voyage is a happy ending (http:/ / www. linux. com/ articles/ 44465) Richard Stallman on 

the Linux/BitKeeper fallout (formerly on NewsForge, currently on Linux.com) 

• The Age (http:/ / www. theage. com. au/ news/ Soapbox/ Crunch-time-for-Linus/ 2005/ 04/ 14/ 1113251731624. 

html) Crunch time for Linus 

• BitKeeper at the "Better SCM" Site (http:/ / better-scm. berlios. de/ bk/ ) - a collection of articles and essays about 

BitKeeper and its history.

ikiwiki 23 

ikiwiki 

Developer(s) Joey Hess et al 

Initial release 


Written in Perl 

29 April 2006 [1] 

Operating system Unix-like 

Type Wiki software 

3.20100122 [2] / 3.14159 was (July 16, 2009) [3] 

License GNU General Public License#Version 2 + 

Website http:/ / ikiwiki. info/ 

ikiwiki is a wiki software system designed by Joey Hess. 

Design 

ikiwiki compiles wiki pages into HTML pages for publication. Unlike conventional wiki software, ikiwiki stores its 

pages in a standard version control system [4] such as Git or Subversion or 6+ others. [5] The term "wiki compiler" was 

coined by ikiwiki's designer to compare the program's function to that of make or gcc for computer software 

projects; [6] other wiki compilers call themselves a "wiki processor". [7] 

ikiwiki is implemented in Perl, although external plugins can be implemented in any language. [8] It supports several 

markup languages, including Markdown, Creole, [9] reStructuredText and Textile. [4] In the simplest case it can 

function as an off-line static web site generator, but it can use cgi to function as a normal web-interfaced wiki as 

well. Login via OpenID is supported. 

ikiwiki is included in various Linux distributions, including Debian. [10] Licensed under the terms of the GNU 

General Public License, version 2 or later, [11] ikiwiki is free software. 

Use as a (possibly-distributed) bug tracker 

Although wikis and bug tracking systems are conventionally viewed as distinct types of software, Ikiwiki can also be 

used as a (possibly-distributed) bug tracking system (for instance, insert an "Index of the 30 most recently fixed 

bugs" via the wikiscript 

[[inline pages="bugs/* and link(done) and !*/Discussion" sort=mtime show=30 archive=yes]] 

); however "Ikiwiki has little structured data except for page filenames and tags, so" its query functionality is not as 

advanced or as user-friendly as some other, non-distributed bug trackers such as Bugzilla. [6] However, structured 

data on the page (beyond tags and path names), as field-value pairs, is being designed. [12]

ikiwiki 24 

See also 

• Bliki 

• Website Meta Language 

References 

[1] Version 1.0, see ikiwiki roadmap (http:/ / ikiwiki. info/ roadmap/ ) 

[2] ( "Download page of ikiwiki" (http:/ / ikiwiki. info/ download/ ). Ikiwiki.info. . Retrieved 2010-01-29.) asserts the latest source is in debian 

repository ( "ikiwiki at debian packages" (http:/ / packages. debian. org/ unstable/ source/ ikiwiki). Packages.debian.org. . Retrieved 

2010-01-29.) which gives the latest version number. 

[3] This version date (July 16, 2009) was listed on this page for version 3.14159 citing ( "ikiwiki at debian packages" (http:/ / packages. debian. 

org/ unstable/ source/ ikiwiki). Packages.debian.org. . Retrieved 2010-01-29.) but that citation doesn't list the version date; it appears one 

would have to download the code & say extract the maximum file date to get the version date. 

[4] "ikiwiki feature "Use a Real RCS"" (http:/ / ikiwiki. info/ features/ #index1h2). Ikiwiki.info. . Retrieved 2010-01-29. 

[5] "ikiwiki Revision Control Systems" (http:/ / ikiwiki. info/ rcs). Ikiwiki.info. . Retrieved 2010-01-29. 

[6] Joey Hess (6 April 2007). "Integrated issue tracking with Ikiwiki" (http:/ / www. linuxworld. com/ news/ 2007/ 

040607-integrated-issue-tracking-ikiwiki. html). LinuxWorld.com. IDG. . Retrieved 7 January 2009. 

[7] PWP Php Wiki Processor (http:/ / www. net-assistant. de/ wiki/ static/ StartPage. html) 

[8] "ikiwiki external plugins" (http:/ / ikiwiki. info/ plugins/ write/ external/ ). Ikiwiki.info. . Retrieved 2009-08-10. 

[9] "Creole plugin page of Ikiwiki" (http:/ / ikiwiki. info/ plugins/ creole/ ). Ikiwiki.info. . Retrieved 2009-08-10. 

[10] debian/copyright (http:/ / packages. debian. org/ changelogs/ pool/ main/ i/ ikiwiki/ current/ copyright). Retrieved March 20, 2008. 

[11] License at ikiwiki web page (http:/ / ikiwiki. info/ freesoftware/ ) 

[12] "ikiwiki.info/todo/structured_page_data" (http:/ / ikiwiki. info/ todo/ structured_page_data). . Retrieved 2010-01-29. 


• Official website (http:/ / ikiwiki. info/ ) 

• ikiwiki at WikiMatrix (http:/ / www. wikimatrix. org/ show/ ikiwiki)


Subversion (software) 

Developer(s) Community, and developers from CollabNet, Elego, VisualSVN, WANdisco 

Initial release October 20, 2000 


Development status Active 

Written in C 

Operating system Cross-platform 


License Apache License 

1.6.13 [1] (October 1, 2010) [ +/− [1] 

] 

Website http:/ / subversion. apache. org/ 

In software development, Apache Subversion (formerly called Subversion [2] , command name svn (Swedish 

pronunciation: [svɛn]) ) is a revision control system founded and sponsored in 2000 by CollabNet Inc. Developers use 

Subversion to maintain current and historical versions of files such as source code, web pages, and documentation. 

Its goal is to be a mostly-compatible successor to the widely used Concurrent Versions System (CVS). 

The open source community has used Subversion widely: for example in projects such as Apache Software 

Foundation, Free Pascal, FreeBSD, GCC, Django, Ruby, Mono, SourceForge, ExtJS, Tigris.org, PHP, Python and 

MediaWiki. Google Code also provides Subversion hosting for their open source projects. BountySource systems 

use it exclusively. CodePlex offers access to Subversion as well as to other types of clients. 

The corporate world has also started to adopt Subversion. A 2007 report by Forrester Research recognized 

Subversion as the sole leader in the Standalone Software Configuration Management (SCM) category and as a strong 

performer in the Software Configuration and Change Management (SCCM) category. [3] 

Subversion uses the Apache License, making it free software and open source. 

History 

The Subversion project was founded by CollabNet in 2000 as an effort to write an open-source version-control 

system which operated much like CVS but which fixed the bugs and supplied some features missing in CVS. By 

2001, Subversion had advanced sufficiently to host its own source code. [4] In November 2009 Subversion was 

accepted into Apache Incubator: this marked the beginning of the process to become a standard top-level Apache 

project. [5] It became a top-level Apache project on February 17, 2010. [6] 

Features 

• Commits as true atomic operations (interrupted commit operations would otherwise cause repository 

inconsistency or corruption). 

• Renamed/copied/moved/removed files retain full revision history. 

• The system maintains versioning for directories, renames, and file metadata (but not for timestamps). Users can 

move and/or copy entire directory-trees very quickly, while retaining full revision history. 

• Versioning of symbolic links. 

• Native support for binary files, with space-efficient binary-diff storage.


• Apache HTTP Server as network server, WebDAV/Delta-V for protocol. There is also an independent server 

process called svnserve that uses a custom protocol over TCP/IP. 

• Branching and tagging as cheap operations, independent of file size (though Subversion itself does not distinguish 

between a tag, a branch, and a directory) 

• Natively client–server, layered library design. 

• Client/server protocol sends diffs in both directions. 

• Costs proportional to change size, not to data size. 

• Parsable output, including XML log output. 

• Open source licensed — Apache License in the projected 1.7 release; prior versions use a derivative of the 

Apache Software License, v1.1 

• Internationalized program messages. 

• File locking for unmergeable files ("reserved checkouts"). 

• Path-based authorization. 

• Language bindings for C#, PHP, Python, Perl, and Java. 

• Full MIME support - users can view or change the MIME type of each file, with the software knowing which 

MIME types can have their differences from previous versions shown. 

Repository types 

Subversion offers two types of repository storage — FSFS and Berkeley DB. 

FSFS 

FSFS works faster on directories with a large number of files and takes less disk space, due to less logging. [7] 

Beginning with Subversion 1.2, FSFS is the default data store for new repositories. 

Berkeley DB 

Subversion has some limitations with Berkeley DB usage when a program that accesses the database crashes or 

terminates forcibly. No data loss or corruption occurs, but the repository is offline while Berkeley DB replays the 

journal and cleans up any outstanding locks. When using Berkeley DB repository, the only way to use it safely is on 

the dedicated server and by a single server process running as one user, according to Version Control with 

Subversion. [8] Existing tools for Berkeley DB repository recovery aren't completely reliable, so system 

administrators need to make frequent repository backups . 

Repository access 

Access to Subversion repositories can take place by the following means: 

1. Local filesystem or network filesystem, [9] accessed by client directly. This mode uses the file:///path 

access scheme. 

2. WebDAV/Delta-V (over http or https) using the mod_dav_svn module for Apache 2. This mode uses the 

http://host/path access scheme or https://host/path for secure connections using ssl. 

3. Custom "svn" protocol (default port 3690), using plain text or over SSH. This mode uses either the 

svn://host/path access scheme for unencrypted transport or svn+ssh://host/path scheme for 

tunneling over ssh. 

All three means can access both FSFS and Berkeley DB repositories. 

Any 1.x version of a client can work with any 1.x server. Newer clients and servers have additional features and 

performance capabilities, but have fallback support for older clients/servers. [10]


Layers 

Internally, a Subversion system comprises several libraries arranged as layers. Each performs a specific task and 

allows developers to create their own tools at the desired level of complexity and specificity. 

Fs 

Repos 

The lowest level; it implements the versioned filesystem which stores the user data. 

Concerned with the repository built up around the filesystem. It has many helper functions and handles the 

various "hooks" that a repository may have, e.g. scripts that run when an action is performed. Together, Fs and 

Repos constitute the "filesystem interface". 

mod_dav_svn 

Provides WebDAV/Delta-V access through Apache 2. 

Ra file:///path/ for local access, http://host/path/ or https://host/path/ for WebDAV access, or svn://host/path/ or 

svn+ssh://host/path/ for the SVN protocol. 

Client, Wc 

Handles "repository access", both local and remote. From this point on, repositories are referred to using 

URLs, e.g. 

The highest level. It abstracts repository access and provides common client tasks, such as authenticating users 

or comparing versions. Subversion clients use the Wc library to manage the local working copy. 

Filesystem 

One can view the Subversion filesystem as 

"two-dimensional" [11] . Two coordinates are used to 

unambiguously address filesystem items: 

• Path (regular path of Unix-like OS filesystem) 

• Revision 

Each revision in a Subversion filesystem has its own 

root, which is used to access contents at that revision. 

Files are stored as links to the most recent change; thus 

a Subversion repository is quite compact. The system 

consumes storage space proportional to the number of 

changes made, not to the number of revisions. 

The Subversion filesystem uses transactions to keep 

changes atomic. A transaction operates on a specified 

revision of the filesystem, not necessarily the latest. 

The transaction has its own root, on which changes are 

made. It is then either committed and becomes the 

latest revision, or is aborted. The transaction is actually 

a long-lived filesystem object; a client does not need to 

commit or abort a transaction itself, rather it can also 

begin a transaction, exit, and then can re-open the 

transaction and continue using it. Multiple clients can 

access the same transaction and work together on an 

atomic change, though no existing clients expose this capability.


Properties 

One important feature of the Subversion filesystem is properties: simple name=value pairs of text. Properties occur 

in two different places in the Subversion filesystem. The first is on filesystem entries (i.e., files and directories). 

These are versioned just like other changes to the filesystem. Users can add any property they wish, and the 

Subversion client uses a set of properties, which it prefixes with 'svn:'. 

svn 

svn 

svn 

svn 

svn 

svn 

svn 

svn 

svn 

executable : Makes files on Unix-hosted working copies executable. 

mime-type : Stores the MIME type of a file. Affects the handling of diffs and merging. 

ignore : A list of filename patterns to ignore in a directory. Similar to CVS's .cvsignore file. 

keywords : A list of keywords to substitute into a file when changes are made. The file itself must also 

reference the keywords as $keyword$ or $keyword:...$. This is used to maintain certain information 

(e.g., author, date of last change, revision number) in a file without human intervention. 

The keyword substitution mechanism originates from rcs [12] and from cvs. 

eol-style : Makes the client convert end-of-line characters in text files. Used when the working copy is 

needed with a specific EOL style. "native" is commonly used, so that EOL's match the user's OS EOL style. 

Repositories may require this property on all files to prevent inconsistent line endings, which can cause a 

problem in itself. 

externals : Allows parts of other repositories to be automatically checked-out into a sub-directory. 

needs-lock : Specifies that a file is to be checked out with file permissions set to read-only. This is 

designed for use with the locking mechanism. The read-only permission reminds one to obtain a lock before 

modifying the file: obtaining a lock makes the file writable, and releasing the lock makes it read-only again. 

Locks are only enforced during a commit operation. Locks can be used without setting this property. However, 

that is not recommended, because it introduces the risk of someone modifying a locked file; they will only 

discover it has been locked when their commit fails. 

special : This property isn't meant to be set or modified directly by users. As of 2010 only used for having 

symbolic links in the repository. When a symbolic link is added to the repository, a file containing the link 

target is created with this property set. When a Unix-like system checks out this file, the client converts it to a 

symbolic link. 

mergeinfo : Used to track merge data (revision numbers) in Subversion 1.5 (or later). This property is 

automatically maintained by the merge command, and it is not recommended to change its value 

manually. [13] 

Subversion also uses properties on revisions themselves. Like the above properties on filesystem entries the names 

are completely arbitrary, with the Subversion client using certain properties prefixed with 'svn:'. However, these 

properties are not versioned and can be changed later. 

svn


svn 

svn 

date : the date and time stamp of a revision 

author : the name of the user that submitted the change(s) 

log : the user-supplied description of the change(s) 

Branching and tagging 

Subversion uses the inter-file branching model from Perforce [14] to handle branches and tags. A branch is a separate 

line of development. [15] Tagging involves creating a snapshot of the repository's content, which, unlike a branch, is 

not expected to change in the future. 

The system sets up a new branch or tag by using the 'svn copy' command, which should be used in place of the 

native operating system mechanism. Subversion does not create an entire new file version in the repository with its 

copy. Instead, the old and new versions are linked together internally and the history is preserved for both. The 

copied versions take up only a little extra room in the repository because Subversion saves only the differences from 

the original versions. 

All the versions in each branch maintain the history of the file up to the point of the copy, plus any changes made 

since. One can "merge" changes back into the trunk or between branches. To Subversion, the only difference 

between tags and branches is that changes should not be checked into the tagged versions. Due to the differencing 

algorithm, creating a tag or a branch takes very little additional space in the repository. 

Current limitations and problems 

Visualization of a simple Subversion project 

A known problem in Subversion affects the implementation of the file and directory rename operation. As of 2010, 

Subversion implements the renaming of files and directories as a "copy" to the new name followed by a "delete" of 

the old name. Only the names change, all data relating to the edit history remains the same, and Subversion will still 

use the old name in older revisions of the "tree". However, Subversion may become confused when files are 

modified and moved in the same commit. This can also cause problems when a move conflicts with edits made 

elsewhere, [16] for example during merging branches. [17] The Subversion 1.5 release addressed some of these 

scenarios while others remain problematic. [18] 

As of 2010 Subversion lacks some repository-administration and -management features. For instance, someone may 

wish to edit the repository to permanently remove all historical records of certain data. Subversion does not have 

built-in support to achieve this simply. [19] 

Subversion stores additional copies of data on the local machine, which can become an issue with very large projects 

or files, or if developers work on multiple branches simultaneously. These .svn directories on the client side can 

become corrupted by ill-advised user activity. [20] The "svn cleanup" command helps in case of internal lock caused


by unfinished operation. 

Subversion does not store the modification times of files. As such, a file checked out of a subversion repository will 

have the 'current' date (instead of the modification time in the repository), and a file checked into the repository will 

have the date of the check-in (instead of the modification time of the file being checked in). This might not always 

be what is wanted. [21] To mitigate this third party solutions exist that allow for preserving modification time and 

[22] [23] 

other filesystem meta-data. 

Subversion does not use a distributed revision control model. Ben Collins-Sussman, one of the designers of 

Subversion, believes a centralised model would help prevent "insecure programmers" from hiding their work from 

other team members. [24] Some users of version control systems see the centralised model as detrimental; famously, 

Linus Torvalds attacked [25] Subversion's model and its developers (calling them "morons"). 

While Subversion stores filenames as Unicode, it does not specify if precomposition or decomposition is used for 

certain accented characters (such as é). Thus, files added in SVN clients running on some operating systems (such as 

OS X) use decomposition encoding, while clients running on other operating systems (such as Linux) use 

precomposition encoding, with the consequence that those accented characters do not display correctly if the local 

[26] [27] 

SVN client is not using the same encoding as the client used to add the files. 

By design, the svn log command is always recursive: trying to access the history of a directory systematically pulls 

out the history of its entire hierarchy. A workaround is not to use the command line but use a sophisticated SVN 

client with filtering capabilities. 

Subversion tags 

This subsection focuses on tags but parts of it also apply to branches. 

Revision numbers are difficult to remember in any version-control system. For this reason most systems offer 

symbolic tags as user-friendly references to them. Subversion does not have such a feature and what its 

documentation recommends to use instead is very different in nature. Instead of implementing tags as references to 

points in history, Subversion recommends taking snapshots and storing them in a well-known subdirectory ("tags/") 

in the space of the repository tree. 

This history-to-space projection causes at least two problems: 

1. Once a snapshot has been taken, the system does not remember which revision it came from. This is the difference 

between a copy and a reference. This makes some operations less convenient and others impossible. For instance a 

naive svn diff -r tag1:tag2 myfile does not work; it is slightly more complicated than that to achieve. Other 

operations like for instance svn log -r tag1:tag2 myfile are just impossible. Only a few predefined references are 

available: HEAD, BASE, PREV and COMMITTED. 

2. When two (ideally independent) object types live in the repository tree, a "fight to the top" can ensue. In other 

words it is often difficult to decide at which level to create the "tags/" subdirectory: 

trunk/componentfoo/ 

/componentbar/ 

tags/1.1/componentfoo/ 

/componentbar/ 

or componentfoo/trunk/ 

/tags/1.1/ 

componentbar/trunk/ 

/tags/1.1/ 

To address such problems, posters on the Subversion mailing lists have suggested a new feature called "labels" or 

"aliases". [28] SVN labels would more closely resemble the "tags" of other systems such as CVS or git. As of 2010 

this suggestion has not progressed.


Development and implementation 

CollabNet has continued its involvement with Subversion, but the project runs as an independent open source 

community. In November 2009 the project was accepted into the Apache Incubator, aiming to become part of the 

Apache Software Foundation's efforts. [29] Since March 2010, the project is formally known as Apache Subversion, 

being a part of the Apache Top-Level Projects. [30] 

In October 2009 WANdisco announced the hiring of core Subversion committers as the company moved to become 

a major corporate sponsor of the project. This included Hyrum Wright, president of the Subversion Corporation and 

release manager for the Subversion project since early 2008, who joined the company to lead its open source 

team. [31] 

The Subversion open-source community does not provide binaries, but potential users can download binaries [32] 

from volunteers. While the Subversion project does not include an official graphical user interface (GUI) for use 

with Subversion, third parties have developed a number of different GUIs, along with a wide variety of additional 

ancillary software. 

Development Roadmap 

The Subversion committers normally have at least one or two new features under active development at any one 

time. As of January 2010 the major goals for the next version of Subversion included a streamlined HTTP transport 

to improve performance and a rewritten working-copy library. [33] 

Other work in progress includes SubversionJ (a JAVA API) and implementation of the Obliterate command, similar 

to that provided by Perforce. Both of these enhancements are being sponsored by WANdisco. [34] 

Source code hosting with SVN 

The following websites provide free source code hosting for SVN repositories: 

• Alioth 

• Assembla 

• BerliOS 

• Betavine 

• Freepository 

See also 



• Comparison of Subversion clients 

• Subversion also integrates with Aba_CM_Enablement 

Notes 

[1] http:/ / en. wikipedia. org/ wiki/ Template%3Alatest_stable_software_release%2Fsubversion 

[2] "Subversion becomes Apache Subversion" (http:/ / subversion. apache. org/ news. html#news-20100217). Apache Software Foundation. . 

[3] "The Forrester Wave: Software Change and Configuration Management, Q2 2007" (http:/ / www. collab. net/ forrester_wave_report/ index. 

html). Forrester Research. . 

[4] "Subversion's History", section of Version Control with Subversion (http:/ / svnbook. red-bean. com/ ), version 1.4 

[5] Subversion joins forces with Apache (http:/ / www. sdtimes. com/ link/ 33886) by David Rubinstein in SD Times November 4, 2009. 

[6] (http:/ / subversion. wandisco. com/ component/ content/ article/ 1/ 43. html) via subversion community 

[7] Strategies for Repository Deployment (http:/ / svnbook. red-bean. com/ en/ 1. 4/ svn. reposadmin. planning. html#svn. reposadmin. basics. 

backends)


[8] Ben Collins-Sussman, Brian W. Fitzpatrick, C. Michael Pilato. "SVN Documentation Chapter 5" (http:/ / svnbook. red-bean. com/ en/ 1. 4/ 

svn. reposadmin. planning. html#svn. reposadmin. basics. backends. bdb). O'Reilly. . 

[9] Berkeley DB relies on file locking and thus should not be used on (network) filesystems which do not implement them 

[10] SVN 1.5 release notes (http:/ / subversion. tigris. org/ svn_1. 5_releasenotes. html) 

[11] Basic Merging (http:/ / svnbook. red-bean. com/ nightly/ en/ svn. branchmerge. basicmerging. html#svn. branchmerge. basicmerging. 

resurrect) 

[12] http:/ / www. openbsd. org/ cgi-bin/ man. cgi?query=rcs& sektion=1#KEYWORD+ SUBSTITUTION Keyword substitution keywords in 

cvs(1) 

[13] Subversion Properties (http:/ / svnbook. red-bean. com/ en/ 1. 5/ svn. ref. properties. html) 

[14] Inter-File Branching: A Practical Method for Representing Variants (http:/ / www. perforce. com/ perforce/ branch. html) 

[15] Branching / Tagging — TortoiseSVN (http:/ / tortoisesvn. net/ docs/ release/ TortoiseSVN_en/ tsvn-dug-branchtag. html) 

[16] Implement true renames (http:/ / subversion. tigris. org/ issues/ show_bug. cgi?id=898) 

[17] Advanced Merging (http:/ / svnbook. red-bean. com/ en/ 1. 5/ svn. branchmerge. advanced. html#svn. branchmerge. advanced. moves) 

[18] Copy/move-related improvements in Subversion 1.5 (http:/ / subversion. tigris. org/ svn_1. 5_releasenotes. html#copy-move-improvements) 

[19] svn obliterate (http:/ / subversion. tigris. org/ issues/ show_bug. cgi?id=516) 

[20] Downsides of Subversion 1.4 for configuration management in large (http:/ / www. docstoc. com/ docs/ 15112930/ 

Downsides-of-Subversion-14-for-configuration-management-in-large) 

[21] Issue 1256 (http:/ / subversion. tigris. org/ issues/ show_bug. cgi?id=1256) at Tigris.org 

[22] FreezeAttrib (saves/restores file attributes using properties) (http:/ / sourceforge. net/ projects/ freezeattrib/ files/ ) 

[23] FSVS (Fast System VerSioning) (http:/ / fsvs. tigris. org/ ) 

[24] Programmer Insecurity @ iBanjo (http:/ / blog. red-bean. com/ sussman/ ?p=96) 

[25] Google Tech Talk video (http:/ / www. youtube. com/ watch?v=4XpnKHJAok8) and its transcript (https:/ / git. wiki. kernel. org/ index. php/ 

LinusTalk200705Transcript) 

[26] subversion: Issue 2464 (http:/ / subversion. tigris. org/ issues/ show_bug. cgi?id=2464) 

[27] SmartSVN - Subversion/SVN Client: Problems with umlauts in file names on Mac OS X (http:/ / www. syntevo. com/ smartsvn/ 

techarticles. html?page=problems. macos-special-characters) 

[28] Subversion mailing lists (http:/ / svn. haxx. se/ users/ ) 

[29] http:/ / www. open. collab. net/ news/ press/ 2009/ svn-asf. html Collabnet Press Release 

[30] http:/ / www. open. collab. net/ news/ press/ 2010/ apache. html Collabnet Press Release regarding Apache subversion 

[31] http:/ / opensource. sys-con. com/ node/ 1239202 WANdisco Press Release 

[32] http:/ / subversion. apache. org/ packages. html 

[33] http:/ / subversion. apache. org/ roadmap. html Subversion Roadmap 

[34] http:/ / www. cmcrossroads. com/ index. php?Itemid=100152& catid=101:news-and-announcements& 

id=13065:wandisco-presents-new-initiatives-for-the-subversion-open-source-project-& option=com_content& view=article WANdisco Press 

Release on CM Crossroads 

References 

• C. Michael Pilato, Ben Collins-Sussman, Brian W. Fitzpatrick; Version Control with Subversion; O'Reilly; ISBN 

0-596-00448-6 (1st edition, paperback, 2004, full book online (http:/ / svnbook. red-bean. com/ ), mirror (http:/ / 

mentalpointer. com/ Subversion/ svn-book. html)) 

• Garrett Rooney; Practical Subversion; Apress; ISBN 1-59059-290-5 (1st edition, paperback, 2005) 

• Mike Mason; Pragmatic Version Control Using Subversion; Pragmatic Bookshelf; ISBN 0-9745140-6-3 (1st 

edition, paperback, 2005) 

• William Nagel; Subversion Version Control: Using the Subversion Version Control System in Development 

Projects; Prentice Hall; ISBN 0-13-185518-2 (1st edition, paperback, 2005)


Further reading 

• Dispelling Subversion FUD (http:/ / www. red-bean. com/ sussman/ svn-anti-fud. html) by Ben Collins-Sussman 

(Subversion developer), as of 2004-12-21 


• Official Site (http:/ / subversion. apache. org) 

• Previous official site (http:/ / subversion. tigris. org/ ) Not all content has yet been migrated to the new official site. 

• Version Control with Subversion (http:/ / svnbook. red-bean. com/ ), an O'Reilly book available for free online 

• Subversion (http:/ / www. dmoz. org/ Computers/ Software/ Configuration_Management/ Tools/ Subversion/ / ) 

at the Open Directory Project 

• HOWTO setup Subversion for Windows with Apache (http:/ / svn. spears. at/ ) (English) 

• Subversion usage Tutorial (http:/ / pointbeing. net/ weblog/ 2009/ 03/ command-line-subversion-tutorial-part-1. 

html) 

• Subversion Community Site (http:/ / subversion. wandisco. com) 

List of revision control software 

This is a list of notable software for revision control. 

Local only 

In the local-only approach, all developers must use the same computer system. 

Free 

• Revision Control System (RCS) — features separate backward deltas for faster access to the trunk tip compared 

to SCCS and an improved user interface, at the cost of slow branch tip access and missing support for 

included/excluded deltas 

• Source Code Control System (SCCS) — part of UNIX; based on interleaved deltas, can construct versions as 

arbitrary sets of revisions 

Distributed model 

In the distributed approach, each developer works directly with his or her own local repository, and changes are 

shared between repositories as a separate step. 

Open source 

• Aegis — written by Peter Miller, mature software, filesystem-oriented, limited network support. It has support for 

distributed revision control. 

• ArX — written by Walter Landry, started as a fork of GNU arch, but has been completely rewritten 

• Bazaar — written in Python, originally by Martin Pool and sponsored by Canonical; decentralised, and aims to be 

fast and easy to use; can losslessly import Arch archives 

• Codeville — written in Python originally by Ross Cohen; uses an innovative merging algorithm 

• Darcs — written in Haskell and originally developed by David Roundy; can keep track of inter-patch 

dependencies and automatically rearrange and "cherry-pick" them using a "theory of patches" 

• DCVS — decentralized and CVS-based 

• Fossil — written by D. Richard Hipp for SQLite; distributed revision control, wiki, and bug-tracking


• Git — written in a collection of Perl, C, and various shell scripts, designed by Linus Torvalds based on the needs 

of the Linux kernel project; decentralised, and aims to be fast, flexible, and robust 

• GNU arch 

• LibreSource — configuration management 

• Mercurial — written in Python as an Open Source replacement to BitKeeper; decentralised and aims to be fast, 

lightweight, portable, and easy to use 

• Monotone — developed by the Monotone Team; decentralized in a peer-to-peer way 

• SVK — written in Perl by Kao Chia-liang; built on top of Subversion to allow distributed commits 

Proprietary 

• BitKeeper — was used in Linux kernel development (2002 – April 2005) 

• Code Co-op — peer-to-peer version control system (can use e-mail for synchronization) 

• Sun WorkShop TeamWare — designed by Larry McVoy, creator of BitKeeper 

Client-server model 

In the client-server model, developers use a shared single repository. 

Open source 

• Concurrent Versions System (CVS) — originally built on RCS 

• CVSNT - cross-platform port of CVS that allows case insensitive file names among other changes 

• OpenCVS - compatible with CVS, with emphasis put on security and source code correctness 

• Subversion (svn) — initially released in 2000 [1] . 

• Vesta — build system with a versioning file system and support for distributed repositories 

Proprietary 

• AccuRev — source configuration management tool with integrated issue tracking based on "Streams" that 

efficiently manages parallel and global development; replication server is also available 

• AllFusion Harvest Change Manager — change and configuration management tool by Computer Associates 

• Autodesk Vault - Version control tool specifically designed for Autodesk applications managing the complex 

relationships between design files such as AutoCAD and Autodesk Inventor. 

• ClearCase — SCC compliant configuration management system by IBM Rational Software 

• IBM Configuration Management Version Control (CMVC) — version control system, no longer available. 

• IC Manage Global Design Platfomr (GDP) – design data management for IC design and Perforce infrastructure 

support. 

• codeBeamer - Collaboration and application lifecycle management platform 

• Perforce — Free for use in open source projects. 

• Polytron Version Control System (PVCS) — originally developed by Don Kinzer at Polytron, first released in 

1985 

• Quma Version Control System 

• StarTeam — coordinates and manages software delivery process by Borland; centralized control of digital assets 

and activities 

• Telelogic Synergy - SCC compliant integrated change management and task-based configuration management 

system,Proprietary of IBM. 

• Vault — version control tool by SourceGear (First installation can be used for free) 

• Visual SourceSafe — version control tool by Microsoft; oriented toward small teams


• Visual Studio Team System — process-based client-server suite of tools by Microsoft for larger development 

organizations, incorporating work item tracking, reporting, build automation, unit and web testing, and integration 

with Microsoft Office 

Notes 

[1] http:/ / svn. collab. net/ repos/ svn/ trunk/ CHANGES 

See also 


• Revision control 

• Comparison of free software hosting facilities 


Other comparisons 

• Comments on Open Source Software / Free Software (OSS/FS) Software Configuration Management (SCM) 

Systems (http:/ / www. dwheeler. com/ essays/ scm. html) 

• Quick Reference Guide to Free Software Revision Control Systems (http:/ / zooko. com/ 

revision_control_quick_ref. html) 

• A comparison of some of both proprietary and free of these revision control systems (http:/ / better-scm. berlios. 

de/ comparison/ ) 

• Version-Control Systems for Linux (http:/ / linuxmafia. com/ faq/ Apps/ vcs. html) 

• SCM Price / Feature Comparison (http:/ / www. relisoft. com/ co_op/ vcs_compare. html) ( from the creators of 

Code Co-op ) 

Further reading 

• Bram Cohen's blog entry on version control politics surrounding the Linux kernel (http:/ / www. livejournal. com/ 

users/ bramcohen/ 17319. html) (founder and contributor of Codeville), as of 2005-04-23 

• Dispelling Subversion FUD (http:/ / www. red-bean. com/ sussman/ svn-anti-fud. html) by Ben Collins-Sussman 

(Subversion developer), as of 2004-12-21 

• LWN article (http:/ / lwn. net/ Articles/ 132000/ ): "The Monotone version control system", as of 2005-04-13 

• Configuration Management Tools (http:/ / www. dmoz. org/ Computers/ Software/ Configuration_Management/ 

Tools/ ) at the Open Directory Project 

• IETF Delta-V Working Group (http:/ / www. webdav. org/ deltav/ ) -- Extending the Web with versioning and 

configuration management... (WebDAV)


Comparison of revision control software 

The following tables compare general and technical information for notable revision control and software 

configuration management (SCM) software. This article is not all-inclusive and may become out of date quickly. 

General information 

Software Maintainer Development 

AccuRev 

Bazaar 

BitKeeper 

ClearCase 

Code Co-op 

Codeville 

CVS 

CVSNT 

darcs 

Fossil 

Git 

GNU arch 

status 

AccuRev, Inc. actively 

Canonical 

Ltd. 

developed 

actively 

developed 

BitMover Inc. actively 

developed 

IBM Rational actively 

Reliable 

Software 

Ross Cohen 

The CVS 

Team [4] 

March Hare 

Software [5] 

and 

community 

members. 

The Darcs 

team 

D. Richard 

Hipp 

developed 

actively 

developed 

official site [3] 

offline; latest 

release July 13, 

2007 

maintained but 

new features not 

added 

maintained and 

new features 

under 

development 

actively 

developed 

actively 

developed 

Junio Hamano actively 

developed 

Andy Tai maintained but 

new features not 

added 

Repository model Concurrency 

model 

Client–server Merge or 

lock 

Distributed [1] Merge 

Distributed Merge 

Client–server 

Merge or 

lock [2] 



Client–server Merge 


lock 





License Platforms 

Proprietary 

GPL 

Proprietary 

Proprietary 

Proprietary 

BSD 

GPL 

GPL or 

proprietary 

GPL 

BSD 

GPL 

GPL 

supported 

Any Java Platform 

(Unix-like, 

Windows, Mac 

OS X) 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X 

Linux, Windows, 

AIX, Solaris, HP 

UX, i5/OS, 

OS/390, z/OS, 

Cost 

Non-free $1495 

(enterprise) for each 

license, free 5-user 30 

day trial licenses 

available 

Free 

Non-free Quoted on 

an individual basis. 

Non-free $4600 per 

floating license (held 

for 30-minutes 

minimum per user) 

Windows Non-free $150 per 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X, i5/OS 

Unix-like, 

Windows, Mac 

OS X 

POSIX, Windows, 

Mac OS X, Other 

POSIX, Windows, 

Mac OS X 

Unix-like, 

Windows, Mac 

OS X 

seat 

Free 

Free 

Free for older version 

or £85 commercial 

license for latest 

version of CVS Suite 

or Change 

Management Server 

Free 

Free 

Free 

Free


IC Manage 

LibreSource 

Synchronizer 

Mercurial 

MKS 

Monotone 

Perforce 

Rational 

Team 

Concert[10] 

StarTeam 

Subversion 

(SVN) 

SVK 

Team 

Foundation 

Server 

Synergy 

Vault 

Visual 

SourceSafe 

IC Manage 

Inc. 

Artenum [6] 

actively 

developed 

maintained and 

new features 

under 

development 

Matt Mackall actively 

developed 

MKS Inc actively 

Nathaniel 

Smith, 

Graydon 

Hoare 

Perforce 

Software Inc. 

developed 

actively 

developed 

actively 

developed 


Borland 

(Micro Focus) 

CollabNet, 

Inc.[11] 

Best Practical 

[14] 

developed 

actively 

developed 

actively 

developed 

maintenance 

through 2010, 

no new 

features [15] 

Microsoft actively 

developed 


SourceGear 

LLC [17] 

developed 

actively 

developed 

Microsoft serious bug 

fixes only 

Software Maintainer Development 

status 


Client–server 

extended to 

"tree" [7] 

lock Proprietary 

Merge 



lock 



lock 


lock 


Client–server [12] 

GPL [8] 

GPL 

Proprietary 

GPL 

Proprietary 

Proprietary 

lock Proprietary 

Merge or 

lock [13] 



Client–server and 

Distributed 

lock 

Merge or 

lock 


lock 

Shared Folder Merge or 

lock 

Repository model Concurrency 

model 

Apache/BSD 

style 

Artistic/GPL 

Proprietary 

Proprietary 

Proprietary 

Proprietary 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X 


AIX, Solaris, HP 

UX, i5/OS, 

OS/390, z/OS, 

Windows and 

Cross-platform via 

Java based client 

Unix-like, 

Windows, Mac 

OS X 

Unix-like, 

Windows, Mac 

OS X 

Server: Windows 

Server 2003; 

Clients: Windows 

and Web included 


Unix-like 

Unix-like, Linux, 

Windows 

License Platforms 

Non-free Commercial 

Free 

Free 

Non-free 

Free 

Free for up to 2 users, 

and for OSS 

development; else 

$900 per seat, with 

volume discounts [9] 

Free for up to 10 

users; else non-free 


concurrent, $2500 per 

fixed user. 

Free (Commercial 

support/services 

available) 

Free 

Non-free Licensed 

through MSDN 

subscription or 

through direct buy 

Non-free Contact IBM 

Rational [16] 


user 

Windows Non-free ~$500 per 

supported 

license or single 

license included with 

each MSDN 

subscription. 

Cost


Table Explanation 

• Software: The name of the application that is described. 

• Maintainer: The company or group that is currently taking responsibility for the software's maintenance or 

development 

• Development Status: The current status of the software project 

• Repository model: describes the relationship between various copies of the source code repository. In a 

client–server model, users access a master repository via a client; typically, their local machines hold only a 

working copy of a project tree. Changes in one working copy must be committed to the master repository before 

they are propagated to other users. In a distributed model, repositories act as peers, and users typically have a 

local repository with version history available, in addition to their working copies. 

• Concurrency model: describes how changes to the working copy are managed to prevent simultaneous edits from 

causing nonsensical data in the repository. In a lock model, changes are disallowed until the user requests and 

receives an exclusive lock on the file from the master repository. In a merge model, users may freely edit files, 

but are informed of possible conflicts upon checking their changes into the repository, whereupon the version 

control system may merge changes on both sides, or let the user decide when conflicts arise. Note that distributed 

version control almost always implies a merge concurrency model. 

• License: The license model under which the software is licensed. These can be both free and paid licenses 

• Platforms Supported: The operating systems that the software application currently supports. 

• Cost: The price of the software application 

Technical information 

Software Programming 

language 

History model Scope of 

change 

Revision IDs Network protocols Source 

Code Size 

AccuRev C++, Java Changeset Unknown Numbers custom Unknown 

Bazaar 

Python, Pyrex, 

C [18] 

Snapshot Tree Pseudorandom 

HTTP, SFTP, FTP, custom, custom 

over ssh, custom over HTTP, email 

bundles [19] , WebDAV (with plugin) 

4.1 MB 

BitKeeper C Changeset Tree Unknown Unknown Unknown 

ClearCase 

Code Co-op 

C, Java, Perl Changeset File Numbers HTTP, custom (CCFS), custom 

C++ Changeset 

Unknown 

(MVFS filesystem driver) 

User ID-Ordinal e-mail (MAPI, SMTP/POP3, Gmail), 

LAN 

Unknown 

Unknown 

Codeville Python Unknown Unknown Unknown Unknown Unknown 

CVS C Changeset File Numbers 

CVSNT 

C++ Changeset 

Unknown 

pserver [20], ssh 

Numbers sspi, sserver, gserver, pserver, custom 

over ssh 

3.3 MB 

4.4MiB 

darcs Haskell Patch Tree Numbers HTTP, custom over ssh, email 1.7 MB 

Fossil C Snapshot Tree SHA-1 hashes HTTP 

Git 

C, shell scripts, 

Perl 

Snapshot Tree SHA-1 hashes custom, custom over ssh, rsync, 

HTTP, email, bundles 

7.2 MB [21] 

10.2 MB 

GNU arch C, shell scripts Changeset Tree Numbers WebDAV, HTTP Unknown 

IC Manage C++, C Changeset Unknown Numbers custom Unknown 


Synchronizer 

Java Changeset 

Unknown 

Timestamps HTTP, File-System 

Unknown


Mercurial 

Python, C Changeset Tree 

Numbers, [22] 

SHA-1 hashes 

HTTP, custom over ssh, email 

bundles (with standard plugin) 

1.2 MB 

MKS C, Java Unknown Unknown Numbers HTTP, custom Unknown 

Monotone 

C++ 

Hybrid [23] Tree SHA-1 hashes custom (netsync), custom over ssh, 

file system 

4.4 MB 

Perforce C++, C Changeset Tree Numbers custom Unknown 

Rational Team 

Concert 

Java Changeset 

Unknown 

Numbers REST services over HTTP/HTTPS 

Unknown 

StarTeam C, Java Snapshot Unknown MD5 hashes custom, TCP/IP Unknown 

Subversion 

C Changeset and 

Snapshot 

Tree Numbers custom (svn), custom (svn) over ssh, 

HTTP and SSL (using WebDAV) 

5.2 MB 

SVK Perl Changeset Tree Numbers Unknown Unknown 

Synergy 

Team 

Foundation 

Server 

Java Changeset (text), 

Snapshot(binary) 

C++ and C# Changeset 

Unknown 

Unknown 

Numbers HTTP, custom over ssh, custom 

Numbers SOAP over HTTP or HTTPS 

Unknown 

Unknown 

Vault C# Changeset Unknown Unknown HTTP, HTTPS Unknown 

Visual 


Software Programming 


C Snapshot 

language 

History model Scope of 

Unknown Unknown 

change 


SMB 

Unknown 

Revision IDs Network protocols Source 

• Programming Language: The coding language in which the application is being developed 

Code Size 

• History model: describes the form in which changes are stored in the repository. For example, when a change is 

committed, a system could store a copy of the tree before and after the change (snapshot), or it might instead store 

a copy of the tree before the change and a changeset representing the changes. 

• Scope of change: Describes whether changes are recorded for individual files or for a entire directory trees. 

• Revision IDs: are used internally to identify specific versions of files in the repository. Systems may use 

pseudorandom identifiers, content hashes of revisions, or filenames with sequential version numbers 

(namespace). With Integrated Difference, revisions are based on the Changesets themselves, which can describe 

changes to more than one file. 

• Network protocols: lists the protocols used for synchronization of changes. 

• Source Code Size: Gives the size of the source code in megabytes. 

Features


Software Atomic 

commits 

File 

renames 

Merge 

file 

renames 

Symbolic 

links Pre/post-event 

hooks 

Signed 

revisions 

Merge 

tracking 

End of line 

conversions 

Tags 

International 

AccuRev Yes Yes Yes Yes Yes Yes Yes Yes N/A Yes 

Support 

Bazaar Yes Yes Yes Yes Yes Partial [24] Yes Yes [25] Yes Yes Yes 

BitKeeper Yes Yes 


Unknown Unknown Yes Unknown Yes Unknown 

Unicode 

filename 

support 

Unknown 

Unknown 

ClearCase Partial [26] Yes Yes Yes Yes Yes Yes Yes Yes Yes [27] Unknown 

Code Co-op Yes Yes Yes No Partial No No No Yes Unknown 

Codeville Unknown Unknown 


Unknown Unknown Unknown Unknown Unknown Unknown 

CVS No No No No Partial No No Yes Yes Unknown No 

CVSNT Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes 

darcs Yes Yes Yes No Yes Yes N/A [28] No Yes No 

Fossil Yes Yes 

Unknown 

No No Yes Yes No Yes Yes 

Git Yes Partial [29] Yes Yes Yes Yes Yes Yes Yes Partial [30] 

GNU arch Yes Yes 

Unknown 

Yes Yes Yes 

Unknown Unknown Yes Unknown 

IC Manage Yes Yes No Yes Yes Yes Yes Yes Yes Yes 


Synchronizer 


Yes Yes Yes No Partial [32] No Yes [33] No Yes Unknown 

commits 

File 

renames 

Merge 

file 

renames 

Symbolic 


hooks 

Signed 

revisions 

Merge 

tracking 

End of line 

conversions 

Tags 

International 

Support 

Mercurial Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes [34] No 

MKS No Yes Yes No Yes Unknown No Yes Yes Unknown 

Monotone Yes Yes Yes No [35] Yes 

Yes, 

Unknown 

Unknown 

Unknown 

Unknown 

Partial [31] 

Unknown 

Unknown 

Unknown 

Unicode 

filename 

support 

Unknown 

mandatory Yes Yes Yes Unknown Yes 

Perforce Yes Yes [36] No Yes Yes Yes Yes [37] Yes Yes Yes [38] 

Rational 

Team 

Concert 

StarTeam Yes [41] Yes 

Yes Yes Yes Yes Yes [40] Yes Yes Yes Yes Yes Yes 

Unknown 

Yes No No Yes Yes Yes Yes 

Subversion Yes Yes [42] No Yes Yes No Yes [43] . Yes Partial [44] Yes Yes 

SVK Yes Yes Yes Yes Yes [45] 

Yes [46] Yes Yes Yes Yes 

Yes [39] 

Unknown 

Unknown


Synergy Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes [47] 

Team 

Foundation 

Server 

Yes Yes Yes 

Unknown 

Yes Unknown Yes Unknown Yes Yes 

Vault Yes Yes Yes No Yes No No Yes Yes Unknown 

Visual 



No [48] Unknown 

No 

commits 


File 

renames 

Merge 

file 

renames 

No Yes No No Unknown Yes Yes 

Symbolic 


hooks 


Signed 

revisions 

Merge 

tracking 

End of line 

conversions 

Tags 

International 

Support 

• Atomic commits: refers to a guarantee that all changes made are merged, or that no change at all will be made. 

• File renames: describes whether a system allows files to be renamed while retaining their version history. 

• Merge file renames: describes whether a system can merge changes made to a file on one branch into the same 

file that has been renamed on another branch (or vice versa). If the same file has been renamed on both branches 

then there is a rename conflict that the user must resolve. 

• Symbolic links: describes whether a system allows revision control of symbolic links as with regular files. 

Versioning symbolic links is considered by some people a feature and some people a security breach (e.g., a 

symbolic link to /etc/passwd). Symbolic links are only supported on select platforms, depending on the software. 

• Pre/post event hooks: indicates the capability to trigger commands before or after an action, such as a commit, 

takes place. 

• Signed revisions: refers to integrated digital signing of revisions, in a format such as OpenPGP. 

• Merge tracking: describes whether a system remembers what changes have been merged between which branches 

and only merges the changes that are missing when merging one branch into another. 

• End of line conversions: describes whether a system can adapt the end of line characters for text files such that 

they match the end of line style for the operating system under which it is used. The granularity of control varies. 

Subversion, for example, can be configured to handle EOLs differently according to the file type, whereas 

Perforce converts all text files according a single, per-client setting. 

• Tags: indicates if meaningful names can be given to specific revisions, regardless of whether these names are 

called tags or labels. 

• International Support: indicates if the software has support for multiple language environments and operating 

system 

• Unicode filename support: indicates if the software has support for interoperations under file systems using 

different character encodings. 

Advanced features 

Unknown 

Unknown 

Unknown 

Unicode 

filename 

support


Software RCS 

AccuRev 

Bazaar 

ClearCase 

keyword 

Interactive 

commits 

external 

references 

partial 

checkout/clone 

Yes Unknown Yes Yes 

Yes [49] 

Yes [50] 

Yes [51] No 

permissions timestamp 

execution bit 

only 

execution bit 

only 

preservation 

supported formats 


Yes 

bzr, subversion [52] , git [53] , 

hg [54] , any that has a 

fastexporter 

Yes [55] No No Yes Yes Yes N/A 

CVS Yes No Yes Yes [56] 

darcs No Yes No No [58] 

Partial [57] Yes cvs 

Partial [59] No darcs 

Fossil No Yes No No No Unknown fossil 

Git 

Mercurial 

Rational 

Team 

Concert 

Yes [60] 

Yes [65] 

Yes [61] 

Yes [66] 

Yes [62] 

No [63] 

Yes [67] No 

execution bit 

only 

execution bit 

Yes Yes Yes Yes Yes Unknown 

only 

No [64] git, cvs, subversion, hg, any 

that has a fastexporter 

No 

hg, subversion [68] , git [69] , 

any other format supported by 

the Convert extension [70] 

SVK Unknown Yes [71] Unknown Yes Unknown Unknown subversion 

Subversion 


Yes [72] No Yes [73] Yes Partial [74] 

• RCS keyword: Support of RCS commands 

N/A 

Yes [75] subversion 

• Interactive commits: Interactive commits allow the user to cherrypick the patch-hunks that become part of a 

commit (leaving unselected changes as changes in the working copy), instead of having only a file-level 

granularity. See darcs record [76] . 

• external references: embedding of foreign repositories in the source tree 

• partial checkout/clone: Ability to check out or clone only a specified subdirectory from a repository. 

• permissions: Tracks file permission bits in the revision history. 

• timestamp preservation: Overwrites the last modified filesystem attribute with the commit time upon checkout. 

• supported formats: either read/write support or read-only (conversion, potentially repeated) 

Basic Commands

Software 


repository 

init 

clone pull push local branches checkout 

update 

add 

remove 

move copy 

merge commit 

AccuRev mkdepot No No promote mkstream mkws update add defunct move No merge keep revert No chstream 

Bazaar 

ClearCase 

CVS 

darcs 

Fossil 

Git 

Mercurial 

Monotone 

init clone pull push 

init No No No No checkout edcs 

create-local-branch [77] checkout update add rm mv No merge commit 

mkelem rmname 

mv No merge 

init No No No No checkout update add rm No No 

init get/put pull push 

new/open clone pull push clone/open 

init / init 

--bare 

clone 

N/A [79] get pull add remove move No 

clone/open update add rm/del mv/rename 

fetch [81] push branch clone pull add rm mv 

init clone pull push 

update 

-j 

pull / 

push 

No merge commit 

cp [then] 

git 

add [82] 

merge commit 

bookmark [83] clone pull -u add rm mv copy merge commit 

init clone pull push No checkout update add drop rename No merge commit 

Perforce Unknown Unknown 

SVK svk 

depotmap 

[or] 

svnadmin 

create) 

Subversion svnadmin 

Software 

create 

repository 

init 

Unknown Unknown Unknown edit sync add delete move 

revert 

generate 

bundle 

file 

revert send 

checkin uncheckout/rmver 

commit remove [then] 

update 

record revert 

revert 

Unknown resolve submit revert 

mirror pull push svk copy checkout update add rm mv cp merge commit 

svnadmin [work-around:] [work-around:] 

hotcopy 

svnadmin load 

svnadmin 

dump 

No 

svn 

checkout 

clone pull push local branches checkout 


svn 

update 

update 

svn add svn rm svn mv svn cp 

add 

remove 

move copy 

svn 

merge 

svn 

merge commit 

rebase 

rebase [78] 

No findmerge 

No No 

send 

-o [80] 

Coming 

Soon 


checkout bundle rebase 

revert bundle 

rebase 

[84] 

revert No No 


revert No smerge -I 

commit svn revert No No 

• Commands in green rectangles that are not surrounded by [square brackets] are at an interactive command-line 

prompt. Text in [square brackets] is an explanation of where to find equivalent functionality. 

• repository init: Create a new empty repository (i.e., version control database) 

• clone: Create an identical instance of a repository (in a safe transaction) 

• pull: Download revisions from a remote repository to a local repository 

• push: Upload revisions from a local repository to a remote repository 

• local branches: Create a local branch that does not exist in the original remote repository 

• checkout: Create a local working copy from a (remote) repository 

• update: Update the files in a working copy with the latest version from a repository 

revert 

generate 

bundle 

file 

rebase


• add: Mark specified files to be added to repository at next commit 

• remove: Mark specified files to be removed at next commit (note: keeps cohesive revision history of before and at 

the remove.) 

• move: Mark specified files to be moved to a new location at next commit 

• copy: Mark specified files to be copied at next commit 

• merge: Apply the differences between two sources to a working copy path 

• commit: Record changes in the repository 

• revert: Restore working copy file from repository 

• generate bundle file: Create a file that contains a compressed set of changes to a given repository 

• rebase: Forward-port local commits to the updated upstream head 

Advanced commands 

Software command 

AccuRev 

Bazaar 

aliases 

No 

lock/unlock 

enable file 

locking 

shelve/unshelve 

rollback 

alias No shelve/unshelve uncommit 

cherry-picking 

bisect incoming/outgoing grep 

keep / co revert / purge patch No No No 

merge 

(non-tracking) 

Darcs No No revert/unrevert unrecord yes [85] 

Git [in 

Mercurial 

'.gitconfig' 

file] 

[in '.hgrc' 

file] 

Monotone [in 

No 

No 

stash/stash 

pop [87] 

shelve/unshelve 

(bundled 

extension [88] ) 

reset --hard 

HEAD^ 

rollback 

bisect (bisect 

plugin) 

missing 

--theirs-only/missing 

--mine-only 

grep 

(grep 

plugin) 

trackdown [86] pull/push --dry-run No 

cherry-pick bisect cherry grep 

transplant 

(bundled 

extension [89] ) 

bisect incoming/outgoing grep 

monotonerc] No No kill_rev_locally [90] pluck bisect No No 

Perforce No lock/unlock shelve/unshelve obliterate integ [91] Unknown Unknown grep 

SVK No No No No svk merge No status [92] No 

Subversion No svn lock/unlock No No 

Surround 

SCM No 

Team 

Foundation 

Server 

Unknown 

Software command 

aliases 


sscm 

svnmerge 


yes [93] 

status -u [94] No 

checkin/checkout No sscm rollback No No sscm diffreport No 

[missing 

command name] 

[missing 

lock/unlock shelve 

command name] Unknown Yes Unknown Unknown 

(stash)/unshelve 

rollback 


Unknown 

bisect incoming/outgoing grep


• Commands in green rectangles that are not surrounded by [square brackets] are at an interactive command-line 

prompt. Text in [square brackets] is an explanation of where to find equivalent functionality. 

• command aliases: create custom aliases for specific commands or combination thereof 

• lock/unlock: exclusively lock a file to prevent others from editing it 

• shelve/unshelve: temporarily set aside part or all of the changes in the working directory 

• rollback: remove a patch/revision from history 

• cherry-picking: move only some revisions from a branch to another one (instead of merging the branches) 

• bisect: binary search of a change 

• incoming/outgoing: query the differences between the local repository and a remote one (the patches that would 

be fetched/sent on a pull/push) 

• grep: search repository for lines matching a pattern 

User interfaces 

Software Web interfaces Stand-alone GUIs Integration and/or Plug-ins for IDEs 

AccuRev 

Bazaar 

ClearCase 

Code Co-op 

CVS 

CVSNT 

darcs 

Git 

GNU arch 

Yes Windows (incl. explorer 

integration), Linux, Unix, Mac 

OS X, BeOS available 

can use a plain webserver, 

webserve [96] , Launchpad 

[97] , loggerhead [98] or Trac 

[99] 

included, Clearcase Web 

Interface 

Not necessary since entire 

project is replicated locally 

cvsweb [111] , ViewVC, 

codeBeamer, others 

cvsweb [111] , ViewVC, 

others 

darcs.cgi included; 

darcsweb [114] , Trac 

gitweb, wit, cgit, GitHub, 

gitorious, Trac, codeBeamer 

ArchZoom [122] 

IC Manage included 

Olive [100] , bzr-gtk [101] 

(GTK+), Bazaar Explorer [102] 

(Qt), QBzr [103] (Qt), 

TortoiseBzr (Windows) 

older: MS Windows native, 

Motif-based GUI for Unix-like 

systems, TSO client for z/OS. 

Windows 

TortoiseCVS (Windows 

Explorer), WinCVS, Mac OS X, 

GTK, Qt available 

Windows, Mac OS X, OS/400, 

GTK, Qt available 

under development; 

TortoiseDarcs (Windows 

Explorer), Mac OS X (alpha), 

gitk, git-gui (Tcl/Tk), tig, 

TortoiseGit, qgit, gitg [117] 

(GNOME/GTK), (h)gct (Qt), 

git-cola (Qt), Git Extensions 

[118] (Windows Explorer) 

ArchWay [123] (GTK2), TlaLog 

[124] 

Windows, Linux, Unix, Mac 

OS X 

IntelliJ IDEA ( AccuRev4IDEA 3:rd party plugin [95] ), 

Eclipse, Visual Studio 

Eclipse ( BzrEclipse [104] , QBzrEclipse [105] ), Visual 

Studio ( bzr-visualstudio [106] ), TextMate ( 

TextMateBundle [107] ), Komodo IDE 

Emacs, Eclipse ( IBM Proprietary [108] , Eclipse-CCase 

[109] ), Visual Studio (IBM proprietary), KDevelop 

(standard?), IntelliJ IDEA ( standard in Ultimate 

Edition [110] ) 

Unknown 

Eclipse (Team), KDevelop (standard), IntelliJ IDEA ( 

standard in Community and Ultimate Editions [112] ), 

Emacs (standard VC [113] ), Komodo IDE, BBEdit 

All those that support CVS, plus commercial plugins 

for SCCI, Bugzilla, Build 

Eclipse ( eclipsedarcs [115] ), Emacs ( vc-darcs.el [116] ) 

Eclipse ( JGit/EGit [119] ); Netbeans ( NbGit [57] ); 

Visual Studio ( Git Extensions [118] ); Emacs ( 

extension [120] for standard VC); TextMate ( Git 

TextMate Bundle [121] ); Vim (VCSCommand plugin); 

IntelliJ IDEA >8.1 ( standard in Community and 

Ultimate Editions [61] ); Komodo IDE; Anjuta 

Emacs (standard VC [113] ) 

Emacs, Cadence Design Framwork, Synopsys Custom 

Designer



Synchronizer 

Mercurial 

Monotone 


included [126] , Bitbucket, 

Trac, codeBeamer 

ViewMTN [132] , 

TracMonotone [133] , 

Perforce included, P4Web, P4FTP 

Rational Team 

Concert 

Yes 

StarTeam included 

Subversion 

Synergy 

Team 

Foundation 

Server 

Apache 2 module included, 

WebSVN [140] , ViewSVN 

[141] , ViewVC, Trac, 

SharpForge, sventon [142] , 

Warehouse [143] , 

codeBeamer 

via Telelogic Change 

interface 

included (Sharepoint Server 

used for web services) 

Vault included 

Visual 


none included; SSWI [151] , 

VSS Remoting [152] 

Windows, Linux, Unix, Mac OS 

X available [125] 

Hgk (Tcl/Tk), (h)gct (Qt), 

TortoiseHg [127] (Windows 

Explorer, Nautilus), 

MacMercurial [9] (MacOS X 

10.4 and newer) 

Monotone-Viz [134] (GTK+), 

Guitone [135] (Qt), Monotone 

Browser [136] (GTK+, Perl) 

Windows, Linux, Unix, Mac OS 

X, BeOS available 

Unknown 

IntelliJ IDEA ( hg4idea 3:rd party plugin [128] ), 

Eclipse ( Mercurial Eclipse [129] ), NetBeans ([130]), 

Visual Studio 2008 ([131]), Emacs, Vim 

(VCSCommand plugin), Komodo IDE 

Unknown 

Eclipse, Visual Studio (P4SCC), KDevelop 

(standard?), IntelliJ IDEA ( standard in Ultimate 

Edition [137] ), Komodo IDE, BBEdit, Emacs ( p4.el 

[138] ) 

Eclipse-based GUI Eclipse integration; MS Visual Studio integration 

Windows, Java, Eclipse, Visual 

Studio, BDS2006 integration, 

plus Java command-line 

Java, KDESVN, Mac OS X 

[144] (including Finder 

integration [145] ), Nautilus, Qt, 

RabbitVCS, TortoiseSVN 

(Windows Explorer) 

Windows (incl. explorer 

integration), Linux, Unix 

Windows included; MacOS, 

Unix available 

Windows, Unix-like, Mac OS 

X 

Windows included; Linux, Mac 

OS and Solaris using 

SourceOffSite [153] ; any Java 

VM using SourceAnyWhere for 

VSS [154] 

IntelliJ IDEA ( standard in Ultimate Edition [139] ), 

Visual Studio, JBuilder, Eclipse 

Anjuta, BBEdit, Eclipse ( Subclipse [146] , Emacs 

(standard VC [113] ), IntelliJ IDEA ( standard in 

Community and Ultimate Editions [147] ), KDevelop 

(standard), Komodo IDE, MonoDevelop (standard), 

Netbeans, RabbitVCS (for GEdit), Subversive [148] ), 

TextMate SVNMate plugin [149] ), Visual Studio 

(AnkhSVN, VisualSVN) 

Eclipse (Telelogic proprietary), Visual Studio 

(Telelogic proprietary), IntelliJ IDEA (Telelogic 

proprietary) 

Visual Studio. Java client for Eclipse IDE and IntelliJ 

IDEA ( standard in Ultimate Edition [150] ) 

Visual Studio 2003 and higher, Eclipse 3.2 and higher 

Visual Studio, IntelliJ IDEA ( standard in Ultimate 

Edition [155] ) 

Software Web interfaces Stand-alone GUIs Integration and/or plug-ins for IDEs 

Table explanation 


• Web Interface: Describes whether the software application contains a web interface. A web interface could allow 

the software to post diagnostics data to a website, or could even allow remote control of the software application. 

• GUIs: A GUI is a graphical user interface. If a software product features a GUI its functionality can be accessed 

through application windows as opposed to accessing functionality based upon typing commands at the command 

prompt such as a DOS interface.


• Plug-ins: functionality is available through an Integrated Development Environment. Minimum functionality 

should be to list the revision state of a file and check in/check out files. 

History and adoption 

Software History Notable users 

AccuRev 

Bazaar 

BitKeeper 

ClearCase 

First publicly released in 2002 Clients include: SanDisk, Sony, Orbitz, MCI, 

and Polycom 

Loosely related to baz. Sponsored by Canonical Ltd.. 

Evolved from Sun WorkShop TeamWare 

Developed beginning in 1990 by Atria Software, following concepts 

developed by Apollo Computer in DSEE during the 1980s. The most 

recent version is 7.1.1, released in Dec 2009. 

Code Co-op The first distributed VCS, demoed in 1997 [158], released soon after. 

Ubuntu, Launchpad, KatchTV [156], MySQL, 

GRUB2, Bugzilla, GNU Emacs 

Linux Kernel (2002–2005) and many 

companies [157] 

IBM, Alcatel-Lucent, Cisco, Motorola, 

Siemens, Ericsson, Nokia and other large 

organizations worldwide 

Clients include: Logitech, HP, Ericsson 

CVS First publicly released July 3, 1986; based on RCS thousands of organizations worldwide 

CVSNT 

darcs 

First publicly released 1998; based on CVS. Started by CVS 

developers with the goal adding support for a wider range of 

development methods and processes. 

First announced on April 9, 2003 

Fossil Fossil and SQLite have used Fossil since 21 July 2007. SQLite, Fossil 

Git 

GNU arch 

IC Manage 


Synchronizer 

Mercurial 

Started by Linus Torvalds in April 2005, following the BitKeeper 

controversy. [160] 

Started by Tom Lord, it later became part of the GNU project. Lord 

resigned as maintainer in August 2005. 

Developed by IC Manage, Inc which was founded in 2003 by Shiv 

Sikand and Dean Drako. 

GHC, Mnet, xmonad, Projects Using Darcs 

[159] 

Linux kernel, GNOME, Perl 5 [161], X.Org, 

Cairo, Qt Software, Samba, OpenEmbedded, 

Ruby on Rails, Wine, Fluxbox, Openbox, 

Compiz Fusion, XCB, ELinks, XMMS2, 

e2fsprogs, GNU Core Utilities, DokuWiki 

(Also see list of Git projects [162] ) 

available for GNU Savannah and Gna.org 

projects 

many organizations worldwide [163] 

First publicly released on June 13, 2005 Most of the LibreSource Community 

Started April 6, 2005 by Matt Mackall, following the BitKeeper 

controversy. [160] First released on April 19, 2005 

Monotone First released in April 2003 

Perforce 

Rational Team 

Concert 

Developed by Perforce Software, Inc which was founded in 1995 by 

Christopher Seiwald. 

Version 1.0 released on June, 2008 IBM 

Mozilla, NetBeans, Xine, Xen, OpenJDK, 

OpenOffice.org, OpenSolaris, wmii, 

MoinMoin, Linux-HA, Python [164] (Also see 

list of projects using Mercurial [165] ) 

CTWM, Pidgin, Xaraya [166] 

many organizations worldwide [167], 

FreeBSD[168] 

?


Revision 

Control 

System 

Source Code 

Control 

System 

StarTeam 

Subversion 

SVK 

Synergy 

Team 

Foundation 

Server 

July 1985 RCS is generally (but not always) superseded 

by other systems such as CVS, which began as 

a wrapper on top of RCS. 

Version 1.0 1995 [169]; Developed by StarBase software, acquired by 

Borland(which was acquired by Micro Focus). 

Started in 2000 by CVS developers with goal of replacing CVS 

Authored by Chia-liang Kao with Audrey Tang. First version was on 

November 19, 2003. 1.00 on May 9, 2005. 2.0.0 on Dec 28th, 2006. 

SVK became a product of Best Practical on June 5, 2006. 

Developed beginning in 1988 by Caseware, as AmplifyControl. The 

company was renamed Continuus in 1994, where the product became 

better known as Continuus/CM. Continuus was acquired by Telelogic 

in 1999 shortly after going public; the product was renamed Telelogic 

Synergy. IBM acquired Telelogic in 2008 for integration into their 

Rational tool suite. The product is now known as IBM Rational 

Synergy. 

as the POSIX source-control tool, SCCS is 

widely available on UNIX platforms. Sun 

WorkShop TeamWare uses SCCS files. 

Borland, BT, Cintas, EDS, Kaiser Permanente, 

Met Office, Quest Software, Raymond James, 

Siemens, and many more globally distributed 

companies [170] 

ASF, SourceForge, FreeBSD, Google Code, 

KDE, GCC, Ruby, Mono, PuTTY, Zope, Xiph, 

GnuPG, CUPS, Wireshark, TWiki, Django, 

аvailable on CodePlex, and many organizations 

worldwide [171] 

Request Tracker 

General Motors, BMW, Chrysler, Nokia, 

Philips, Raytheon, Morgan Stanley, Friends 

Provident, Boeing, Lockheed Martin, Siemens 

and other small, medium and large 

organizations worldwide 

First publicly released on March, 2006 Available on CodePlex, Microsoft itself and 

other large organizations worldwide 

Vault First publicly released in February, 2003 Unknown 

Visual 


originally created by a company called One Tree Software, version 

3.1. Company was bought by Microsoft which released version 4.0 of 

VSS around 1995 

Unknown 

Software History Notable users 



• Notable users: is a list of well known projects using the software as their primary revision control system, 

excluding the software itself, followed by a link to a full list if available. 

• History: briefly describes the software's origins and development.


See also 


• Comparison of free software hosting facilities 

References 

[1] Bazaar is a Distributed version control system but it can also be used in a centralized manner (http:/ / bazaar-vcs. org/ Tutorials/ 

CentralizedWorkflow) using lock step development (http:/ / bazaar-vcs. org/ LockStepDevelopment) and checkouts (http:/ / bazaar-vcs. org/ 

CheckoutTutorial). 

[2] In ClearCase, a trigger may be set to allow for the lock model, and this is done at many sites. However, ClearCase development usually takes 

place on private branches where each developer is given their own branch, so the lock vs. merge concurrency model doesn't matter as much. 

Code is merged back to the main branch once the developer is ready to deliver their code to the project. 

[3] http:/ / codeville. org 

[4] http:/ / savannah. nongnu. org/ project/ memberlist. php?detailed=1& group=cvs 

[5] http:/ / march-hare. com/ cvspro/ 

[6] http:/ / www. artenum. com 

[7] "a workspace can be synchronized with more than one LibreSource Synchronizer. As a limitation, the network must have tree topology." says 

LibreSource Synchronizer. 

[8] As of version 2.5, "LibreSource is now released under GPL Version 2" (http:/ / dev. libresource. org/ home/ news/ 

Mature_the_collaborative_forge_LibreSource_now_released_under_GPL). . 

[9] http:/ / www. perforce. com/ perforce/ price. html 

[10] https:/ / jazz. net/ projects/ rational-team-concert/ 

[11] http:/ / www. collab. net/ 

[12] SVK allows Subversion to have Distributed branches. 

[13] In Subversion, a file attribute enables the lock model on per-file basis. This file attribute can be set automatically using file name wildcard 

expressions. 

[14] http:/ / bestpractical. com/ 

[15] "The Future of SVK" (http:/ / lists. bestpractical. com/ pipermail/ svk-devel/ 2009-May/ 001224. html). May 28, 2009. . Retrieved June 6, 

2009. 

[16] http:/ / www. ibm. com/ software/ awdtools/ synergy 

[17] http:/ / www. sourcegear. com 

[18] Bazaar's critical modules are written in Pyrex. They are automatically translated to pure C; except for the patience sorting module, used in 

merge resolution, which is written directly in the C language. 

[19] A Bazaar bundle is a summary diff, with sufficient extra information to preserve history. 

[20] http:/ / www. elegosoft. com/ cvs/ cvsclient. html 

[21] 4 MB of which are sqlite3.c 

[22] Mercurial revision numbers are local to a repository; they can differ from repository to repository depending on in which order merges are 

performed. 

[23] A Monotone's revisions represent changesets and its manifests represent snapshots, each revision is linked to some manifest. But manifests 

are legacy constructs, they aren't kept in the database anymore and reconstructed on the fly if needed. The real work now happen in rosters 

which are hybrid snapshot/changeset structures. 

[24] They can be automatically generated (http:/ / bazaar-vcs. org/ BzrGpgSigning) and manually verified, but verification is not automatic 

[25] EOL conversions are supported since bzr 1.14 (http:/ / doc. bazaar-vcs. org/ bzr. 1. 14/ en/ release-notes/ NEWS. html#bzr-1-14) 

[26] Atomic commit can be enabled for individual checkin's ClearCase 7.1.1 release notes (https:/ / publib. boulder. ibm. com/ infocenter/ cchelp/ 

v7r1m0/ index. jsp?topic=/ com. ibm. rational. clearcase. relnotes. doc/ topics/ c_cc_relnotes_features. htm). 

[27] Support Policy for National Languages and ClearCase (http:/ / www. ibm. com/ support/ docview. wss?uid=swg21229688) 

[28] darcs' patches each bear a unique identifier, impossible to merge twice the same patch in a repository (without destructively modifying 

history using "unsafe" commands). 

[29] Git does not explicitly track renames, because by design it does not track individual files. Renames and split of source files are detected after 

the fact, if the file content does not change dramatically. 

[30] Git itself is not internationalized, just git-gui and gitk (both are shipped with git). 

[31] Git is encoding agnostic and hence can work with all file names without problems. It only may not display them properly in its console 

output. 

[32] Its possible to embed the action in a shell or Ant script. 

[33] A merged is tracked by its workspace origin. 

[34] Mercurial is in the process of being translated to at least dutch and chinese 

[35] It could be done via user level hooks 

[36] Perforce Knowledge Base: Renaming Files (http:/ / www. perforce. com/ perforce/ technotes/ note007. html)


[37] (http:/ / www. perforce. com/ perforce/ technotes/ note009. html) 

[38] (http:/ / kb. perforce. com/ ?article=66) 

[39] (http:/ / kb. perforce. com/ article/ 66/ internationalization-and-localization#i18n) 

[40] Through the procees behaviour components: Operation advisors and Operation participants. http:/ / jazz. net/ library/ article/ 292 

[41] StarTeam supports atomic commits as of version 2006 

[42] Subversion can move a file and conserve its history, if and only if the target of the move is in the same Subversion repository as the source. 

Cross-repository moves require third-party tools such as svk. Also, a rename operation is actually a copy-with-history-and-delete sequence. 

[43] New to SVN 1.5 ( (http:/ / subversion. tigris. org/ svn_1. 5_releasenotes. html#merge-tracking)). A separate tool "svnmerge" ( (http:/ / www. 

dellroad. org/ svnmerge/ )) provides merge tracking for older versions. 

[44] In Subversion, tags are a special case of the more generic "cheap copy" concept of Subversion. Per convention, a tag is a copy into a 

directory named "tags". Because of this, even tags are versioned. See (http:/ / svnbook. red-bean. com/ nightly/ en/ svn. branchmerge. tags. 

html) for more information. The reason for partial support in the table is because Subversion's emulation of tags in this manner does not meet 

the requirement that the tag name can be used in place of any revision identifier wherever the user may be required to enter one. This column 

would be meaningless if the definition were to be loosened enough to encompass Subversion's approach as every version control system 

supports branching and would therefore support tags as well. 

[45] Uses subversion server 

[46] Signature - SVK Wiki (http:/ / svk. bestpractical. com/ view/ Signature) 

[47] in Asian releases, v6.6a to v7.1a 

[48] Version change history is removed upon rename; old name not referenced. 

[49] Bazaar keywords plugin (http:/ / launchpad. net/ bzr-keywords) 

[50] Bazaar interactive plugin (https:/ / launchpad. net/ bzr-interactive) 

[51] Bazaar Externals plugin (http:/ / launchpad. net/ bzr-externals) 

[52] bzr-svn (http:/ / launchpad. net/ bzr-svn) 

[53] bzr-git (http:/ / launchpad. net/ bzr-git) 

[54] bzr-hg (http:/ / launchpad. net/ bzr-hg) 

[55] IBM Rational ClearCase: The ten best triggers (http:/ / www. ibm. com/ developerworks/ rational/ library/ 4311. html#N10496) 

[56] Using alias of the CVSROOT/modules file. 

[57] CVS records executable bit when a file is added, but does not allow changing it later on. 

[58] Darcs can do sparse checkouts from explicit checkpoints on darcs-1 repositories, but not from darcs-2 ones 

[59] Darcs can automatically detect #! scripts and make them executable on checkout. 

[60] The Git FAQ (http:/ / git. wiki. kernel. org/ index. php/ GitFaq#keywords) states that keyword expansion is not a good thing 

[61] add -i and add -p, see git-add(1) Manual Page (http:/ / www. kernel. org/ pub/ software/ scm/ git/ docs/ git-add. html) 

[62] git-submodule(1) Manual Page (http:/ / www. kernel. org/ pub/ software/ scm/ git/ docs/ git-submodule. html) 

[63] The Git Community Handbook (http:/ / book. git-scm. com/ 5_submodules. html) clearly explains that "Git does not allow partial 

checkouts" 

[64] The Git FAQ (http:/ / git. wiki. kernel. org/ index. php/ GitFaq#modtime) explains why preserving modification time is considered harmful 

[65] Mercurial KeywordExtension page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ KeywordExtension) 

[66] Mercurial RecordExtension page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ RecordExtension) 

[67] hgforest repository (http:/ / bitbucket. org/ pmezard/ hgforest-crew/ overview/ ) 

[68] hgsubversion page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ HgSubversion) 

[69] Hg-Git Mercurial Plugin (http:/ / hg-git. github. com/ ) 

[70] Mercurial ConvertExtension page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ ConvertExtension) 

[71] commit --interactive, see SVK::Command::Commit (http:/ / search. cpan. org/ dist/ SVK/ lib/ SVK/ Command/ Commit. pm) 

[72] Keyword Substitution (http:/ / svnbook. red-bean. com/ en/ 1. 4/ svn. advanced. props. special. keywords. html) 

[73] Externals Definitions (http:/ / svnbook. red-bean. com/ en/ 1. 0/ ch07s03. html) 

[74] SVN records file permissions when a file is added, but does not allow changing them later on. 

[75] Disabled by default. 

[76] http:/ / darcs. net/ manual/ node8. html#SECTION00861000000000000000 

[77] bzr-local-branches plugin 

[78] rebase plugin 

[79] darcs doesn't have named branches, local or not, branching is handled solely through repository cloning 

[80] darcs send prepares a bundle of patches, defaults to sending it by mail but can send it to a file instead 

[81] pull is fetch plus merge. 

[82] copies are detected after the fact, much like renames 

[83] Mercurial Bookmarks (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ BookmarksExtension) are similar to local branches, with 

some limitations (http:/ / blog. experimentalworks. net/ 2008/ 11/ mercurial-bookmarks/ ). 

[84] Mercurial rebase extension project's page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ RebaseProject) 

[85] darcs operate on patches not revision, cherrypicking simply consists in pulling a given patch from one repository to another one as long as 

the dependencies are fulfilled


[86] trackdown performs an automated search by repeatedly running a provided command on previous revisions on the working copy until the 

command succeeds (doesn't return an error code) (http:/ / darcs. net/ manual/ node8. html#SECTION008114000000000000000) 

[87] git stash is a multi-level shelve, it's possible to shelve several change groups at the same time 

[88] Mercurial Shelve extension page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ ShelveExtension) 

[89] Mercurial Transplant extension page (http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ TransplantExtension) 

[90] Only works on a local repository and only on revisions without children. The disapprove command might be an alternative. 

[91] http:/ / kb. perforce. com/ article/ 567/ 

[92] svk status lists differences between working copy and repository, not differences between two repositories 

[93] Using the free third-party tool svn-bisect (http:/ / search. cpan. org/ dist/ App-SVN-Bisect/ bin/ svn-bisect) 

[94] svn status lists differences between working copy and repository, not differences between two repositories 

[95] http:/ / accurev4idea. dev. java. net/ 

[96] https:/ / launchpad. net/ bzr-webserve 

[97] http:/ / www. launchpad. net 

[98] http:/ / www. lag. net/ loggerhead 

[99] http:/ / launchpad. net/ trac-bzr 

[100] http:/ / bazaar-vcs. org/ Olive 

[101] http:/ / bazaar-vcs. org/ bzr-gtk 

[102] http:/ / doc. bazaar. canonical. com/ explorer/ en/ 

[103] http:/ / bazaar-vcs. org/ QBzr 

[104] http:/ / bazaar-vcs. org/ BzrEclipse 

[105] http:/ / bazaar-vcs. org/ QBzrEclipse 

[106] http:/ / launchpad. net/ bzr-visualstudio 

[107] http:/ / bazaar-vcs. org/ TextMateBundle 

[108] http:/ / www. ibm. com/ developerworks/ rational/ library/ content/ 03July/ 2500/ 2834/ ClearCase/ clearcase_plugins. html 

[109] http:/ / eclipse-ccase. sourceforge. net/ 

[110] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#Rational_ClearCase_support 

[111] http:/ / www. freebsd. org/ projects/ cvsweb. html 

[112] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#CVS_Integration 

[113] http:/ / www. gnu. org/ software/ emacs/ manual/ html_node/ emacs/ Version-Control. html 

[114] http:/ / blitiri. com. ar/ p/ darcsweb/ 

[115] http:/ / eclipsedarcs. org/ 

[116] http:/ / www. pps. jussieu. fr/ ~jch/ software/ repos/ vc-darcs/ 

[117] http:/ / trac. novowork. com/ gitg/ 

[118] http:/ / code. google. com/ p/ gitextensions/ 

[119] http:/ / freshmeat. net/ projects/ jgit 

[120] http:/ / www. emacswiki. org/ cgi-bin/ wiki/ Git 

[121] http:/ / gitorious. org/ projects/ git-tmbundle 

[122] http:/ / migo. sixbit. org/ software/ archzoom/ 

[123] http:/ / www. nongnu. org/ archway/ 

[124] http:/ / www. univ-paris12. fr/ lacl/ pommereau/ tla/ 

[125] Any OS that support a Java Virtual Machine 1.5 

[126] hgweb for single-repository access and hgwebdir for multiple repository access from a single HTTP address 

[127] http:/ / tortoisehg. org 

[128] http:/ / www. bitbucket. org/ willemv/ hg4idea 

[129] http:/ / www. vectrace. com/ mercurialeclipse/ 

[130] http:/ / wiki. netbeans. org/ wiki/ view/ MercurialVersionControl 

[131] http:/ / www. newsupaplex. pp. ru/ hgscc_news_eng. html 

[132] http:/ / grahame. angrygoats. net/ viewmtn. shtml 

[133] http:/ / tracmtn. 1erlei. de 

[134] http:/ / oandrieu. nerim. net/ monotone-viz 

[135] http:/ / guitone. thomaskeller. biz 

[136] http:/ / www. coosoft. plus. com/ software. html 

[137] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#Perforce_Integration 

[138] http:/ / p4el. sourceforge. net/ 

[139] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#StarTeam_Integration 

[140] http:/ / www. websvn. info/ 

[141] http:/ / viewsvn. berlios. de/ 

[142] http:/ / www. sventon. org/ 

[143] http:/ / warehouseapp. com/


[144] http:/ / www. lachoseinteractive. net/ en/ community/ subversion/ svnx/ features/ 

[145] http:/ / scplugin. tigris. org/ 

[146] http:/ / subclipse. tigris. org/ 

[147] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#Subversion_Client_and_Integration 

[148] http:/ / www. eclipse. org/ subversive/ 

[149] http:/ / ciaranwal. sh/ 2007/ 10/ 10/ svn-plug-in-for-textmate 

[150] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#Team_Foundation_Server_integration 

[151] http:/ / www. componentworkshop. com/ Default. aspx 

[152] http:/ / www. sourceremoting. com/ vssr_overview. htm 

[153] http:/ / www. sourcegear. com/ sos/ 

[154] http:/ / www. dynamsoft. com/ Products/ SAW_Overview. aspx 

[155] http:/ / www. jetbrains. com/ idea/ features/ version_control. html#Visual_SourceSafe_Integration 

[156] http:/ / bazaar-vcs. org/ WhoUsesBzr 

[157] http:/ / www. bitkeeper. com/ Customers. html 

[158] http:/ / portal. acm. org/ citation. cfm?id=716428& dl=ACM& coll=portal 

[159] http:/ / wiki. darcs. net/ DarcsWiki/ ProjectsUsingDarcs 

[160] Towards A Better SCM: Revlogs and Mercurial (http:/ / mercurial. selenic. com/ wiki/ Presentations?action=AttachFile& do=get& 

target=ols-mercurial. pdf), presented by Matt Mackall to the Ottawa Linux Symposium, July 2006 

[161] http:/ / dev. perl. org/ perl5/ source. html 

[162] http:/ / git. wiki. kernel. org/ index. php/ GitProjects 

[163] http:/ / icmanage. com/ customer. html 

[164] transition ongoing (http:/ / www. python. org/ dev/ peps/ pep-0374/ #decision) 

[165] http:/ / www. selenic. com/ mercurial/ wiki/ index. cgi/ ProjectsUsingMercurial 

[166] http:/ / www. venge. net/ monotone/ wiki/ ProjectsUsingMonotone 

[167] http:/ / www. perforce. com/ perforce/ customers. html 

[168] http:/ / www. freebsd. org/ doc/ en_US. ISO8859-1/ articles/ p4-primer/ index. html 

[169] http:/ / web. archive. org/ web/ 19980507011804/ demo. starbase. com/ WebDraw+ Old+ Web+ Site/ StarTeam/ StarTeam. htm 

[170] http:/ / www. borland. com/ us/ customers/ profiles/ view-by-product. jsp 

[171] http:/ / subversion. tigris. org/ testimonials. html 


• Comparison between Git and Mercurial (http:/ / code. google. com/ p/ support/ wiki/ DVCSAnalysis) by Google 

(summer 2008) 

• Comments on Open Source Software / Free Software SCM systems (http:/ / www. dwheeler. com/ essays/ scm. 

html) by David A. Wheeler 

• Quick Reference Guide to Free Software Decentralized Revision Control Systems (http:/ / zooko. com/ 

revision_control_quick_ref. html) by Zooko Wilcox-O'Hearn 

• Comparison of commercial Version Control Systems (http:/ / www. relisoft. com/ co_op/ vcs_compare. html) 

from the creators of Code Co-op 

• Version Control System Comparison (http:/ / better-scm. berlios. de/ comparison/ comparison. html) from 

better-scm.berlios.de 

• Evaluation of distributed source code management solutions for OpenSolaris (http:/ / opensolaris. org/ os/ 

community/ tools/ scm/ ) by Sun 

• Comparison of CVS and Subversion (http:/ / www. softeng. rl. ac. uk/ media/ uploads/ publications/ 2010/ 03/ 

cvs-svn. pdf)


Revision control 

Revision control, also known as version control, source control or 

software configuration management (SCM), is the management of changes 

to documents, programs, and other information stored as computer files. It is 

most commonly used in software development, where a team of people may 

change the same files. Changes are usually identified by a number or letter 

code, termed the "revision number", "revision level", or simply "revision". 

For example, an initial set of files is "revision 1". When the first change is 

made, the resulting set is "revision 2", and so on. Each revision is associated 

with a timestamp and the person making the change. Revisions can be 

compared, restored, and with some types of files, merged. 

Version control systems (VCSs - singular VCS) most commonly run as 

stand-alone applications, but revision control is also embedded in various 

types of software such as word processors (e.g., Microsoft Word, 

OpenOffice.org Writer, KWord, Pages, etc.), spreadsheets (e.g., Microsoft 

Excel, OpenOffice.org Calc, KSpread, Numbers, etc.), and in various content 

management systems (e.g., Drupal, Joomla, WordPress). Integrated revision 

control is a key feature of wiki software packages such as MediaWiki, 

DokuWiki, TWiki etc. In wikis, revision control allows for the ability to 

revert a page to a previous revision, which is critical for allowing editors to 

track each other's edits, correct mistakes, and defend public wikis against 

vandalism, spam and spammers. 

Software tools for revision control are essential for the organization of 

multi-developer projects. [1] 

Overview 

Example history tree of a 

revision-controlled project. 

Engineering revision control developed from formalized processes based on tracking revisions of early blueprints or 

bluelines. This system of control implicitly allowed returning to any earlier state of the design, for cases in which an 

engineering dead-end was reached in the development of the design. Likewise, in computer software engineering, 

revision control is any practice that tracks and provides control over changes to source code. Software developers 

sometimes use revision control software to maintain documentation and configuration files as well as source code. 

Also, version control is widespread in business and law. Indeed, "contract redline" and "legal blackline" are some of 

the earliest forms of revision control, and are still employed with varying degrees of sophistication. An entire 

industry has emerged to service the document revision control needs of business and other users, and some of the 

revision control technology employed in these circles is subtle, powerful, and innovative. The most sophisticated 

techniques are beginning to be used for the electronic tracking of changes to CAD files (see product data 

management), supplanting the "manual" electronic implementation of traditional revision control. 

As teams design, develop and deploy software, it is common for multiple versions of the same software to be 

deployed in different sites and for the software's developers to be working simultaneously on updates. Bugs or 

features of the software are often only present in certain versions (because of the fixing of some problems and the 

introduction of others as the program develops). Therefore, for the purposes of locating and fixing bugs, it is vitally 

important to be able to retrieve and run different versions of the software to determine in which version(s) the


problem occurs. It may also be necessary to develop two versions of the software concurrently (for instance, where 

one version has bugs fixed, but no new features (branch), while the other version is where new features are worked 

on (trunk). 

At the simplest level, developers could simply retain multiple copies of the different versions of the program, and 

label them appropriately. This simple approach has been used on many large software projects. While this method 

can work, it is inefficient as many near-identical copies of the program have to be maintained. This requires a lot of 

self-discipline on the part of developers, and often leads to mistakes. Consequently, systems to automate some or all 

of the revision control process have been developed. 

Moreover, in software development, legal and business practice and other environments, it has become increasingly 

common for a single document or snippet of code to be edited by a team, the members of which may be 

geographically dispersed and may pursue different and even contrary interests. Sophisticated revision control that 

tracks and accounts for ownership of changes to documents and code may be extremely helpful or even necessary in 

such situations. 

Revision control may also track changes to configuration files, such as those typically stored in /etc or /usr/local/etc 

on Unix systems. This gives system administrators another way to easily track changes made and a way to roll back 

to earlier versions should the need arise. 

Source-management models 

Traditional revision control systems use a centralized model where all the revision control functions take place on a 

shared server. If two developers try to change the same file at the same time, without some method of managing 

access the developers may end up overwriting each other's work. Centralized revision control systems solve this 

problem in one of two different "source management models": file locking and version merging. 

Atomic operations 

Computer scientists speak of atomic operations if the system is left in a consistent state even if the operation is 

interrupted. The commit operation is usually the most critical in this sense. Commits are operations which tell the 

revision control system you want to make a group of changes you have been making final and available to all users. 

Not all revision control systems have atomic commits; notably, the widely-used CVS lacks this feature. 

File locking 

The simplest method of preventing "concurrent access" problems involves locking files so that only one developer at 

a time has write access to the central "repository" copies of those files. Once one developer "checks out" a file, 

others can read that file, but no one else may change that file until that developer "checks in" the updated version (or 

cancels the checkout). 

File locking has both merits and drawbacks. It can provide some protection against difficult merge conflicts when a 

user is making radical changes to many sections of a large file (or group of files). However, if the files are left 

exclusively locked for too long, other developers may be tempted to bypass the revision control software and change 

the files locally, leading to more serious problems.


Version merging 

Most version control systems allow multiple developers to edit the same file at the same time. The first developer to 

"check in" changes to the central repository always succeeds. The system may provide facilities to merge further 

changes into the central repository, and preserve the changes from the first developer when other developers check 

in. 

Merging two files can be a very delicate operation, and usually possible only if the data structure is simple, as in text 

files. The result of a merge of two image files might not result in an image file at all. The second developer checking 

in code will need to take care with the merge, to make sure that the changes are compatible and that the merge 

operation does not introduce its own logic errors within the files. These problems limit the availability of automatic 

or semi-automatic merge operations mainly to simple text based documents, unless a specific merge plugin is 

available for the file types. 

The concept of a reserved edit can provide an optional means to explicitly lock a file for exclusive write access, even 

when a merging capability exists. 

Baselines, labels and tags 

Most revision control tools will use only one of these similar terms (baseline, label, tag) to refer to the action of 

identifying a snapshot ("label the project") or the record of the snapshot ("try it with baseline X"). Typically only one 

of the terms baseline, label, or tag is used in documentation or discussion; they can be considered synonyms. 

In most projects some snapshots are more significant than others, such as those used to indicate published releases, 

branches, or milestones. 

When both the term baseline and either of label or tag are used together in the same context, label and tag usually 

refer to the mechanism within the tool of identifying or making the record of the snapshot, and baseline indicates the 

increased significance of any given label or tag. 

Most formal discussion of configuration management uses the term baseline. 

Distributed revision control 

Distributed revision control (DRCS) takes a peer-to-peer approach, 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 bona-fide repository. [2] Distributed revision control conducts synchronization by exchanging 

patches (change-sets) 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. [3] 

Rather, communication is only necessary when pushing or pulling changes to or from other peers. 

• Each working copy effectively functions as a remote backup of the codebase and of its change-history, providing 

natural protection against data loss. [3]


Integration 

Some of the more advanced revision-control tools offer many other facilities, allowing deeper integration with other 

tools and software-engineering processes. Plugins are often available for IDEs such as Oracle JDeveloper, IntelliJ 

IDEA, Eclipse and Visual Studio. NetBeans IDE and Xcode come with integrated version control support. 

Common vocabulary 

[4] [5] 

Terminology can vary from system to system, but some terms in common usage include: 

Baseline 

Branch 

Change 

An approved revision of a document or source file from which subsequent changes can be made. See 

baselines, labels and tags. 

A set of files under version control may be branched or forked at a point in time so that, from that time 

forward, two copies of those files may develop at different speeds or in different ways independently of each 

other. 

Change list 

Checkout 

Commit 

Conflict 

A change (or diff, or delta) represents a specific modification to a document under version control. The 

granularity of the modification considered a change varies between version control systems. 

On many version control systems with atomic multi-change commits, a changelist, change set, or patch 

identifies the set of changes made in a single commit. This can also represent a sequential view of the source 

code, allowing the examination of source "as of" any particular changelist ID. 

A check-out (or co) creates a local working copy from the repository. A user may specify a specific revision 

or obtain the latest. 

A commit (checkin, ci or, more rarely, install, submit or record) occurs when writing or merging a copy of 

the changes made to the working copy into the repository. 

A conflict occurs when different parties make changes to the same document, and the system is unable to 

reconcile the changes. A user must resolve the conflict by combining the changes, or by selecting one change 

in favour of the other. 

Delta compression 

Most revision control software uses delta compression, which retains only the differences between successive 

versions of files. This allows for more efficient storage of many different versions of files. 

Dynamic stream 

Export 

Head 

Import 

A stream in which some or all file versions are mirrors of the parent stream's versions. 

An export resembles a check-out except that it creates a clean directory tree without the version-control 

metadata used in a working copy. Often used prior to publishing the contents. 

The most recent commit.


Label 

Mainline 

Merge 

An import involves copying a local directory tree (that is not currently a working copy) into the repository for 

the first time. 

See tag. 

Similar to trunk, but there can be a mainline for each branch. 

A merge or integration is an operation in which two sets of changes are applied to a file or set of files. Some 

sample scenarios are as follows: 

• A user, working on a set of files, updates or syncs their working copy with changes made, and checked into 

the repository, by other users. [6] 

• A user tries to check-in files that have been updated by others since the files were checked out, and the 

revision control software automatically merges the files (typically, after prompting the user if it should 

proceed with the automatic merge, and in some cases only doing so if the merge can be clearly and reasonably 

resolved). 

• A set of files is branched, a problem that existed before the branching is fixed in one branch, and the fix is 

then merged into the other branch. 

• A branch is created, the code in the files is independently edited, and the updated branch is later incorporated 

Promote 

Repository 

Resolve 

into a single, unified trunk. 

The act of copying file content from a less controlled location into a more controlled location. For example, 

from a user's workspace into a repository, or from a stream to its parent. [7] 

The repository is where files' current and historical data are stored, often on a server. Sometimes also called a 

depot (for example, by SVK, AccuRev and Perforce). 

The act of user intervention to address a conflict between different changes to the same document. 

Reverse integration 

Revision 

Ring 

Share 

Stream 

Tag 

The process of merging different team branches into the main trunk of the versioning system. 

Also version: A version is any change in form. In SVK, a Revision is the state at a point in time of the entire 

tree in the repository. 

See tag. 

The act of making one file or folder available in multiple branches at the same time. When a shared file is 

changed in one branch, it is changed in other branches. 

A container for branched files that has a known relationship to other such containers. Streams form a 

hierarchy; each stream can inherit various properties (like versions, namespace, workflow rules, subscribers, 

etc.) from its parent stream.


Trunk 

Update 

A tag or label refers to an important snapshot in time, consistent across many files. These files at that point 

may all be tagged with a user-friendly, meaningful name or revision number. See baselines, labels and tags. 

The unique line of development that is not a branch (sometimes also called Baseline or Mainline) 

An update (or sync) merges changes made in the repository (by other people, for example) into the local 

working copy. [6] 

Working copy 

See also 

The working copy is the local copy of files from a repository, at a specific time or revision. All work done to 

the files in a repository is initially done on a working copy, hence the name. Conceptually, it is a sandbox. 



• Software configuration management (SCM) 

• Software versioning 

• Versioning file system 

References 

[1] "Rapid Subversion Adoption Validates Enterprise Readiness and Challenges Traditional Software Configuration Management Leaders" 

(http:/ / www. eetimes. com/ press_releases/ bizwire/ showPressRelease. jhtml?articleID=608063& CompanyId=2). EETimes. May 17, 2007. . 

Retrieved June 1, 2007. "Version management is essential to software development and is considered the most critical component of any 

development environment." 

[2] Wheeler, David. "Comments on Open Source Software / Free Software (OSS/FS) Software Configuration Management (SCM) Systems" 

(http:/ / www. dwheeler. com/ essays/ scm. html). . Retrieved May 8, 2007. 

[3] O'Sullivan, Bryan. "Distributed revision control with Mercurial" (http:/ / hgbook. red-bean. com/ hgbook. html). . Retrieved July 13, 2007. 

[4] Collins-Sussman, Ben; Fitzpatrick, B.W. and Pilato, C.M. (2004). Version Control with Subversion (http:/ / svnbook. red-bean. com/ ). 

O'Reilly. ISBN 0-596-00448-6. . 

[5] Wingerd, Laura (2005). Practical Perforce (http:/ / safari. oreilly. com/ 0596101856). O'Reilly. ISBN 0-596-10185-6. . 

[6] Collins-Sussman, Ben; Brian W. Fitpatrick, and C. Michael Pilato. "Version Control with Subversion" (http:/ / svnbook. red-bean. com/ en/ 1. 

5/ svn. tour. cycle. html#svn. tour. cycle. resolve). . Retrieved 8 June 2010. "The G stands for merGed, which means that the file had local 

changes to begin with, but the changes coming from the repository didn't overlap with the local changes." 

[7] Accurev Concepts Manual, Version 4.7. Accurev, Inc.. July, 2008. 


• Eric Sink's Source Control HOWTO (http:/ / www. ericsink. com/ scm/ source_control. html) A primer on the 

basics of version control 

• Visual Guide to Version Control (http:/ / betterexplained. com/ articles/ a-visual-guide-to-version-control/ ) 

• Better SCM Initiative: Comparison (http:/ / better-scm. berlios. de/ comparison/ ) A useful summary of different 

systems and their features.


Article Sources and Contributors 

Mercurial Source: http://en.wikipedia.org/w/index.php?oldid=388580812 Contributors: AMackenzie, Amniarix, Amux, Ananthshrinivas, Arcy, Aron.gombas, Ash, Aurelien, BenAllard, Bk0, 

Boredzo, Bytesmiths, CalculusAndCoffee, ChristianEdwardGruber, Chtito, Cmcqueen1975, CornedBee, Cybercobra, DD2K, Damian Yerrick, Daniel.Cardenas, Dgc, Digana, Dmitry Dzhus, EAi, 

Edhoprima, ElTchanggo, Emurphy42, FaranNegarestan, Fmitha, Frap, Free Software Knight, FrenchIsAwesome, Fudoreaper, Gary King, Gioto, Gjbloom, Gogo hr, Grandscribe, Gronky, 

Gutworth, Harryboyles, Heimy, Hervegirod, Hyperfusion, IByte, IanVaughan, Imz, Ingvildr, Intgr, JWWalker, Jeffreymcmanus, Jemts, Jonik, Jp8900308, Kaźmierczyk Krzysztof, Kbrose, 

Kl4m-AWB, Krier.cedric, LimeHat, Maju wiki, MarSch, Marinovi, MarkusHagenlocher, Martin Geisler, Martin.komunide.com, Matthewn, Mewtu, Mfedyk, Mhi, Mitchan, Mordomo, Naive 

cynic, NeuroBells123, Nickpd, Nsavch, Omnifarious, Orderinchaos, Orderud, Orgads, Palfrey, Paul Delhanty, Pax:Vobiscum, Pdz, Peak, Peepeedia, Pen1234567, Peso, Peter.arrenbrecht, Piet 

Delport, Pne, RG72, Robert.maclean, Sdudah, Sebastian Goll, Simetrical, Skalee, Sligocki, Slipstream, Smimram, Snowsmash, Tghw, The RedBurn, Thumperward, ThurnerRupert, Timothy 

Clemans, Tuggler, Tuxcantfly, Venkytv, W Hukriede, Wesley, Wmahan, Yoghurt, Zuckerberg, 127 anonymous edits 

Distributed revision control Source: http://en.wikipedia.org/w/index.php?oldid=387192388 Contributors: Adjohnson916, Allen Moore, Apotheon, Asparagus, Bartosz, Bluebusy, Cander0000, 

CharlesC, Dondegroovily, Escape Orbit, Furrykef, Greenrd, Grimboy, Ilari Halminen, Imz, Iridescent, JDubman, Jaalto, Jfromcanada, Kateshortforbob, Kenny Strawn, Kevins, Kockster, 

LapoLuchini, MarsRover, Martijn Hoekstra, Mdupont, Medovina, MicahElliott, Modify, Ninly, Niteowlneils, Paul Pogonyshev, PaulColby, RossPatterson, Rtc, Samer.hc, Sergiy Kheylyk, 

SunCreator, Thumperward, Triwbe, Tuxcantfly, Tzadikv, VictorAnyakin, Wace, Woon Tien Jing, 51 anonymous edits 

Git (software) Source: http://en.wikipedia.org/w/index.php?oldid=388995597 Contributors: A.M., A2Kafir, Adam Katz, Alerante, Alex.muller, Alisha.4m, AlistairMcMillan, Alphax, 

Amalthea, Andre.goddard, AngelKnight, Arichnad, Arjun G. Menon, Artw, Atheuz, Audriusa, Banpei, Bender235, Betterworld, Beyazid, Bigbluefish, Blazar, Bluebusy, Boyski, 

Bramschoenmakers, Brentonson, Camponez, Cburnett, CesarB, Chaos.squirrel, Choas, Chr1syr, Chx1975, CiaPan, Ck3d, ConradPino, Coonsta, Cybercobra, Daev, Daniel Thompson, 

Daniel.Cardenas, Daniel.ugra, DataWraith, David Gerard, David.hilton.p, Davidswelt, Debarshiray, Deleteme42, Demitsu, Dennis714, DigitalPig, Direvus, DonPaolo, DopefishJustin, Dpotapov, 

Drizzd, Dscho, Dwheeler, Eaglizard, Eddie Nixon, Ehamberg, Eleveneleven, Eloquence, Enormekever, Erlendaakre, Eschnett, Eturkay, EvanCarroll, Ewlyahoocom, Fanf, Fatespeaks, Felix 

Wiemann, Fiftyquid, Fleasoft, Folajimi, Fragglet, Francis Tyers, FrancisTyers, FrankTobia, Frap, Frecklefoot, Fred Bradstadt, Fredrik, Free Software Knight, Furrykef, Gaius Cornelius, Gdavidp, 

Generalk, Gil mo, GivePeasAChance, Gjmulhol, Glenn, Gloin, Gogo hr, Gonzonoir, Greg Tyler, GregorB, Grendelkhan, Gronky, Groxx, Grutness, Gustavb, Gwern, Hairy Dude, Hanifbbz, 

Hannes Röst, Hawaiian717, Henon, Henridv, Hervegirod, Hooperbloob, Hpv, Hu2hugo, Hulten, HumbertoDiogenes, Hypersw, ISoron, IainDavidson, IanVaughan, Iani, Ino5hiro, Int19h, Intgr, 

IvanLanin, J Di, J.delanoy, JLaTondre, JamesTeterenko, Jeffrey Smith, Jeffz1, Jengelh, Jfcarr, Jherland, Jidanni, Jnareb, John Vandenberg, Jonnycando, Juhtolv, Jun-Dai, Junkblocker, Justin545, 

KYSoh, Kesla, Kevinbsmith, Kinema, King of Hearts, Kl4m-AWB, Kntrabssi, Kugland, Kwerle, Landroni, Leonid Volnitsky, LimeHat, Linuxbeak, Liontooth, Liyf, MBisanz, Maddyunlocked, 

Majromax, Mamling, Martin Geisler, Marudubshinki, Matonen, MattFS218, MattGiuca, Matthieu fr, Meandtheshell, Meonkeys, Meow, Methmann, Mfedyk, MikeRS, Mitchan, Modargo, 

Mosquitopsu, Moxfyre, MrDolomite, MrOllie, Mugwumpjism, Myrdred, NapoliRoma, Ninly, Nippysaurus, Noam, Orderud, Oska, Padraigk, Pagingmrherman, Palfrey, Paradoja, PaulJackson99, 

Pcap, Pelerin2, Pengo, Petteri, Phil.a, Pjrm, Pnorcks, Qutezuce, Qwe, RCX, Raggha, RainerBlome, RandalSchwartz, Raul654, Raysonho, Reedy, Renku, ReyBrujo, Rich Farmbrough, 

Rigmahroll, Rjwilmsi, Rogerdpack, RossPatterson, Rossami, Rst, STGM, Samdutton, Sandrafromgermany, Sanxiyn, Saric, Sathallrin, Secleinteer, Shanes, Shd, Shentino, Shoujun, SimenH, 

Sivaraj, Sligocki, Smyth, Socrates32, Spasquali, SpeedyGonsales, Spyhawk, Stassats, Stevenj, Stevertigo, Strimo, Subsolar, Superm401, Sverdrup, Svick, Sycarr, Sysmonblog, TakuyaMurata, 

Tchoř, Tedickey, Thayvian, Thepizzaking, Thumperward, ThurnerRupert, Thv, TigerShark, Tim abell, Toofishes, Tpk5010, Trevor37, Trödel, Tuxcantfly, Uncle G, Unicodemonkey, VanGore, 

Vanuan, Vegpuff, Venkytv, Veratien, Viatropos, Vl'hurg, Warren, Wmahan, Woohookitty, Woseph, Wwwwolf, Xan2, Zzzawir, Ævar Arnfjörð Bjarmason, Žiedas, 494 anonymous edits 

BitKeeper Source: http://en.wikipedia.org/w/index.php?oldid=376843146 Contributors: -fin, Ahoerstemeier, Andrewtn, Ashawley, Benabell, Betacommand, Betterworld, Bk0, BlueAzure, 

Bryan Derksen, CesarB, Ciphergoth, Computerjoe, Connelly, Cyde, Elifarley, Elpincha, Evice, Evil Eccentric, Finlay McWalter, Frap, Fredrik, Furrykef, Glenn Willen, Graue, Grendelkhan, 

Guaka, Guppie, Hairy Dude, Hyuri, Inclusivedisjunction, Jamelan, Jamesday, Jdtyler, Jnareb, Josephw, Jrka, Male1979, Marudubshinki, Mellery, Mipadi, Mkcmkc, Morwen, Moxfyre, Naddy, 

Nixdorf, Ob, Ortzinator, Pakaran, Pascal666, Pengo, Rich Farmbrough, Seitz, Shlomif, Sikon, Skapur, Sligocki, Stevenj, Sydneyfong, TakuyaMurata, Thv, Tobias, Uncle G, Unixguy, Vsion, 

WikianJim, Wsc9tt, Wuzzeb, 50 anonymous edits 

ikiwiki Source: http://en.wikipedia.org/w/index.php?oldid=380075048 Contributors: Chase me ladies, I'm the Cavalry, CiaranG, Den fjättrade ankan, Fetchcomms, Greenrd, Greg Tyler, Imz, 

Isoxyl, JLaTondre, Jayjg, Josh Triplett, MBParker, Mahahahaneapneap, Merriam, Nomeata, Pcap, Rich Farmbrough, Shaundakulbara, Sverdrup, Tbleher, Thumperward, Tobias Bergemann, 

Xan2, Yaron K., Yworo, 9 anonymous edits 

Subversion (software) Source: http://en.wikipedia.org/w/index.php?oldid=356190295 Contributors: ABLsaurusRex, AThing, Abelson, Abi79, Aceeca, Adamantios, Adrian.benko, Agencius, 

Akamu37, Al001, AlistairMcMillan, AliveFreeHappy, Allanhalme, Alvin-cs, Ameaijou, Amitverma, AndreaPersephone, Andrew Bond, Anna512, Annabel, Ansell, Appraiser, Arrataz, 

Arseny1992, ArthurBarrett, Arwhyte, Autrijus, Avonderluft, Barefootguru, Bdesham, Bdude, Beethoven05, Beland, Beradrian, Billportelli, Bk0, Bodhi.root, Boredzo, Borisvolfson, BraneJ, 

Brettporter, Brighterorange, Btwied, Btyner, Cabcodespring, Campuscodi, Carribeiro, Catapult, Chealer, Chiak, Concavelenz, Coralguy80, Corti, Crcd, Csabo, Cshay, Cysiek10, DCEvoCE, Dan 

Forever, Daniel.Cardenas, Dany4762, Darkride, Darshana.jayasinghe, David Gerard, Derprediger, Djg2006, Doopokko, Dougher, DrSpice, Drrngrvy, Dulciana, Duplicity, Dwlegg, Ecerutti, Ed 

g2s, Ehn, Ejrh, Eliyahu S, Eloquence, Enochlau, EoGuy, Esycat, Ext9, FlashSheridan, Fractal3, Fragglet, Fran Rogers, Fred Bradstadt, Free Software Knight, FrenchIsAwesome, Ftiercel, 

Furrykef, GTyron, Gameguy43, Giddie, Gilesmorant, Gordonrox24, Gottowik, Greenrd, Gronky, Gstein, Gtrmp, Guidohaarmans, Gutworth, Hawaiian717, Hede2000, Hermzz, Hm2k, Hoylen, 

Husky, Hyperthermia, IMSoP, Ian wild, IanVaughan, Iceb, Icek, Idumont2007, Illustir, Imroy, Imz, Intgr, IvanLanin, J JMesserly, JHunterJ, JLaTondre, Jacosi, JamesHenstridge, Jdm64, 

Jehochman, Jeremy Visser, John L Wallace, John Vandenberg, Jonas Olson, Jopsen, Julesd, Juliano, Jwestbrook, Jwmillerusa, Kae, Karam.Anthony.K, Karson, Kenguest, Kfogel, Khalid hassani, 

Kingdon, Kjoonlee, Kkinder, Kl4m-AWB, Knutux, Kolja,nahimov, Korg, KublaChaos, Kukini, LDiracDelta, Lee Carre, Leigh, Lesionarian, Levin, Lion.guo, Liorkaplan, Lithrium, LittleDan, 

Loqui, Lpangelrob, Luuse, Mahpatel, Mailtodaman, Marchash, Mark Renier, MarkPilgrim, Marmelad, MarsRover, Martin Tux Simons, Martinjglover, Marudubshinki, Marysunshine, Mathrick, 

Matt Crypto, Mauget, Mbbeaton, Mebden, MerlinYoda, Michael Hardy, Michael Sinz, Mikeblas, Mindmatrix, Mintrick, Mipadi, MisterSheik, Mitul0520, Mkegelmann, Mml, Moa3333, Morte, 

Motine, Moxfyre, Moyda, Mpeg4codec, MrOllie, Mtoley, Mxn, NeARAZ, Neilc, Nertzy, Nialsh, Nick Levine, Nikai, Nixeagle, Nux, Oberiko, Ojigiri, Olekva, Olivier Debre, Orderud, Owlsfan, 

PEJL, Pablo-flores, Pallaert, Parklandspanaway, Patrick, Pburba, PeteVerdon, Peu, Peyre, Phmarek, Pne, Polymorp, Prodoc, PseudoSudo, Pwae, Quartz25, R3m0t, Rajah, Rama, Ramanavelan, 

Rankinke, Rayngwf, Rcalhoun, ReCover, Reagle, Red Thrush, RedWolf, Redprimary, Reelrt, Regibox, Reinderien, Renku, RenniePet, Reub2000, RickBeton, Rjwilmsi, Rob.daemon, Robert K S, 

RossPatterson, RoyBoy, Rufous, Ruud Koot, SCEhardt, SF007, Sae1962, Sam Staton, Sami Kerola, Samuella, Sandrafromgermany, SarekOfVulcan, Sbressler, Scarlet Lioness, Schapel, SchreyP, 

SchwaberWocky, Sega381, Seidenstud, Shaddack, Sheremetyev, Shirishag75, Shlomif, Sietse Snel, Signalhead, Sirsam, Sligocki, Slreynolds, Smcleish, Smfair, Smrose, Snaq, Somercet, 

Spacy73, Stan231, Stannered, Stassats, Stephan Leeds, Stevenjgarner, Stevertigo, Stillnotelf, Strait, Stroebti, StuffOfInterest, Stwalkerster, SugarKane, SunCreator, Sunny256, Superm401, 

SvenGodo, Svick, Swpb, Syncrosoft, TFOWR, Taw, Teratornis, Tetracube, The Anome, TheDarkNomad, Thue, Thumperward, Thv, Tidam, Tobias Bergemann, Tobius, Tosha, TropicalMonkey, 

Ubik70, User A1, Vectro, VictorReinhart, Vikrant42, Vincent Jacobs, Vints, Vsion, WadeSchuette, Wesley, Whitlockjc, WikHead, Winterst, Witepa, Wlievens, Wmahan, Wondersz, Wwwwolf, 

Xompanthy, YordanGeorgiev, Youngwr, ZealousCoder, Zedlander, Zenzee, Zephyrfalcon, Ævar Arnfjörð Bjarmason, 495 anonymous edits 

List of revision control software Source: http://en.wikipedia.org/w/index.php?oldid=389286972 Contributors: .digamma, 2D, A1, Afc, Alensha, Allen Moore, Alxeedo, Amfahrj, 

Arndbergmann, ArthurBarrett, Ashley Y, Bartosz, Bill Clark, Ccady, CesarB, ChrisCork, CiaranG, ClaudineChionh, Connelly, Cspurrier, DEddy, Darth Panda, David-Sarah Hopwood, 

DenMoren, Diegof79, Douga, Douglaurac98, Dpotapov, Dreadstar, EagleOne, Eisnard, Elego, Ericlee748, Etnies99, EwanMcNab, Excirial, Faginwiki, Faltenin, Firien, Flet, Fractal3, 

Francesco.biccari, Frecklefoot, Furrykef, Gbjbaanb, Greenman, Haakon, Harej, Haricotvert, Harmony07, Heron, IanOsgood, Imroy, Intachange, J voris, JLaTondre, JRHorse, Jack Merridew, 

Jackey Jones, Jemfinch, Jpgolay, Juliano, Jwarhol, Karnesky, Kevins, Kfogel, Kgrandpak, Khalid hassani, Kippson, Langpavel, Lee Carre, Lpgeffen, Malcolmxl5, MarkMascolino, 

Mckaysalisbury, MidrangeMan, Mike Payne, Moa3333, Molyneux.peter, Motio, Moxfyre, Mukis, Mware, NellieBly, Netstar, Ninly, Ohnoitsjamie, Ompty, Open haris, Orderud, Payton11, 

Pelago, Peter S., Peter.vk, PetersonPro1, Petra.hegarty, Plolet, PsychoSafari, Raboof, Ratiocination, Red Director, Reinyday, Reisio, RossPatterson, Samer.hc, Sara Cooper, Satori Son, Seitz, Shd, 

SickTwist, Sigma 7, Ssentinel, StaticSan, SteinbDJ, Sundae, Tedickey, Theman01, Themshow, Thiseye, Thv, Timc, Tnizani, Tobias Bergemann, Trashbird1240, Tvarnoe, Urimargalit, Usafi, 

VanRysselberghe, Vsion, Warren, WhiteLightning, WiKiMan3L, Windharp, Wmahan, Wnoise, Workshare, Wormholio, Xsgauthier, Youngwr, Ziroby, Ævar Arnfjörð Bjarmason, 243 

anonymous edits 

Comparison of revision control software Source: http://en.wikipedia.org/w/index.php?oldid=390459450 Contributors: 127, AdamSiska, Afc, Aigenta, Akmg, AlanBarrett, Albertvanbiljon, 

Alejandro66, Amfahrj, Andrea Lamar, Andreas S., Angedelamort, ArchiSchmedes, Arichnad, ArthurBarrett, Astronaut, Bartosz, Beland, Bigbluefish, Bigfoot00, Boemanneke, Bones0, 

Bytesmiths, C777, Cburnett, Ccady, Ceros, Chapliong, Chnacat, Chris the speller, Ciphergoth, CompIsMyRx, Craig Stuntz, Crazeinc, CrazyTerabyte, CrisLander, Ctrlsoft, Cubonic, Damien 

Cassou, DanConnolly, DanielVasicek, Danipen, Dark ixion, Dave Yost, David-Sarah Hopwood, DejanLekic, Demono, Dpotapov, Drake Wilson, Drizzd, Dulciana, Dvarrazzo, Earle Martin, EdC, 

Ehudm1, Emreg00, EnTerr, Epimienta, Etaekema, Etherboy, EvanED, Excirial, F.svehla, Fale, Faltenin, Fedwa, FraGGod, Fraterm, Frecklefoot, FutureDomain, Gaal, GarenParham, Gaz Man, 

Ghen, Glyphobet, Grafen, Greenman, Greenrd, GreyCat, Gstein, Gudeldar, Gê, HPSCHD, Haakon, Heirpixel, Huazheng, IByte, ISC PB, IanOsgood, IanVaughan, Ideaworks, Imachuchu, Imroy, 

Imz, Infofarmer, Intachange, Intgr, Intheairalot, JLaTondre, Jack Merridew, Jameinel, Jdm64, Jec, Jengelh, Jeremy Visser, John Vandenberg, John Yesberg, Joke de Buhr, JonJuan, Jonabbey, 

JoshRyan, Juliano, KAtremer, Kae, KampfCaspar, Keramida, Kissedsmiley, Kvangend, Lammig, Larry Hastings, Ldoron, Leachim6, LilHelpa, Lkundrak, Lod, Ludovic Brenta, Luks, MBParker, 

MagnusW, Malcolmxl5, Masklinn, Matthew V Ball, MaxSem, Mccabeusers, Mcld, Mdg149, Merbabu, MichaelDavid1, MichaelPloujnikov, Mikeblas, Miketinte, Mild Bill Hiccup, Mindmatrix, 

Mino, Mister Farkas, Mitchan, Mlevison, Moxfyre, Mskfisher, Mukis, NapoliRoma, Narendra Sisodiya, Nberardi, Nealmcb, NenoLoje, Neoseeker.com, Neustradamus, Nfearnley, Nicholas 

Allen74, OlavN, Optikos, Orderud, Orz, Outmind, Panzi, PaulBoxley, Payton11, Peak, Pehaynes, Pen1234567, Peter.vk, Peter.weseloh, Petra.hegarty, Peu, Pol098, Polluks, Proub, Python, 

RalphMoritz, RandomPrecision, Revolus, Roamingbecki, Roarkh, RobLa, Rriehle, Rskrueger, Rzclawson, S.borchers, SF007, Sanxiyn, Sara Cooper, Schwern, Scottb1978, Sensorflo, Servel333,


Shinmawa, Sid1138, Smoorfoo, St.General, Stassats, Stephan Leeds, Steppres, Stevage, Szilveszter Farkas, Tedickey, Themshow, Thumperward, Tianyi Cui, Timcharper, Timneu22, Tobias 

Bergemann, Tommyd3mdi, Trustable, Tuxcantfly, Urchin22, VMiklos, Van der Hoorn, VladV, Waldir, Warren, Wm243, Wmahan, Wonderstruck, Woseph, XPav, Ysangkok, Zilog Jones, 633 


Revision control Source: http://en.wikipedia.org/w/index.php?oldid=391806712 Contributors: .digamma, 1-is-blue, 16@r, 16x9, A.M., Aitias, Aldie, Alvatov, Ancheta Wis, Antonielly, 

ArneBab, Bartosz, Baudway, Berny, Bevo, Bgpaulus, Bjmiller, Blackeagle, BobBagwill, Boobtimelive, Breakpoint, Brockert, Btwied, Burris, Bursar42, Burschik, Cander0000, CanisRufus, 

Centrx, CesarB, CharlesC, CitizenDAK, Cjcollier, Clkao, Collabi, Cquan, Crossmr, Cyde, CyrilB, DARTH SIDIOUS 2, DRAGON Elemental, Danielx, David Crawshaw, Deagle AP, Degenera, 

Deuchlincoln35, Dionye, Dondegroovily, Dorftrottel, Echion2, Edward, Edward Z. Yang, Eep², Egfrank, Eloquence, Elwikipedista, Erik9, EvanCarroll, Ewlyahoocom, Felixdakat, Flammifer, 

Flash200, Fractal3, Frau K, Frecklefoot, Fryed-peach, Gamefreak2413, Greenrd, Grimboy, Gsmgm, Gurch, Harmil, Hellboy1975, Hhhjjjkkk, IanClatworthy, Imroy, Iridescent, Iulianu, 

IvanLanin, Ixfd64, J-Wiki, Janakan86, Jblack, Jni, Jonabbey, Jose.mira, JoshRyan, Joshbosh, Kate, KennethJ, Kevins, Khym Chanur, Krischik, Ksd5, LeeHunter, Lichen0426, Lotje, Lquilter, 

Luna Santin, Madduck, MarkBrooks, Martinkunev, Memogron, MicahElliott, Michael Allan, Minghong, Moa3333, Moxfyre, Msikma, MyNameIsJackson, Naradapuri, Nashev, NawlinWiki, 

Netsnipe, Nickg, Nigelj, Nikai, ObfuscatePenguin, Ohnoitsjamie, Olivier Debre, Orderud, Pascal666, Peruvianllama, PeteVerdon, Peter.vk, Petra.hegarty, Phil Boswell, PhilipMW, Phoe6, 

PiRSquared17, Piet Delport, Pkchan, Pne, Prodoc, Project2501a, Qxz, R'n'B, Rachana09, Rashack, RedWolf, Rich Farmbrough, Righteye, Rjd0060, Rjwilmsi, Rob Hooft, Robert Illes, Robert 

Merkel, Robth, Rodii, RossPatterson, Ruud Koot, Sabri76, Salgueiro, Sam Korn, Seitz, Shenme, SickTwist, Sietse Snel, Silsor, Sjgcit, Skoczko, Skyezx, Slakr, Snarpel, Soumyasch, Spalding, 

Stevietheman, Sunny256, Synthetik, Talgalili, TechnoGuyRob, Technobadger, Tedickey, Tejas81, Teratornis, Tevildo, Thejoshwolfe, Thiagomacieira, ThomasOwens, Thv, Timkccb, Timneu22, 

Tobias Bergemann, Tommyjb, TruthinQuest, Tue18nov, Tyler McHenry, Tyler Oderkirk, UU, Vcwizard, Voyagerfan5761, Wesley, Weyrick, Wikipelli, Winterst, Wmahan, YUL89YYZ, Yage, 

Yaronf, Yevrah342, Youandme, Zhxjojo, Ziounclesi, 308 anonymous edits

Image Sources, Licenses and Contributors 61 

Image Sources, Licenses and Contributors 

File:Mercurial logo.png Source: http://en.wikipedia.org/w/index.php?title=File:Mercurial_logo.png License: unknown Contributors: Cybercobra 

Image:Hgk.png Source: http://en.wikipedia.org/w/index.php?title=File:Hgk.png License: Public Domain Contributors: Original uploader was Sebastian Goll at en.wikipedia 

File:git-logo.svg Source: http://en.wikipedia.org/w/index.php?title=File:Git-logo.svg License: GNU General Public License Contributors: User:Stannered 

Image:ikiwiki.png Source: http://en.wikipedia.org/w/index.php?title=File:Ikiwiki.png License: GNU General Public License Contributors: ikiwiki project 

File:Subversion.png Source: http://en.wikipedia.org/w/index.php?title=File:Subversion.png License: unknown Contributors: JWWalker, Jwestbrook, Sfan00 IMG, Stannered, Ysangkok, 1 


File:Svn 3D-tree.svg Source: http://en.wikipedia.org/w/index.php?title=File:Svn_3D-tree.svg License: Creative Commons Attribution-Sharealike 2.5 Contributors: User:Marmelad 

File:Subversion project visualization.svg Source: http://en.wikipedia.org/w/index.php?title=File:Subversion_project_visualization.svg License: GNU Free Documentation License 

Contributors: User:Stannered 

File:Revision controlled project visualization-2010-24-02.svg Source: http://en.wikipedia.org/w/index.php?title=File:Revision_controlled_project_visualization-2010-24-02.svg License: GNU 

Free Documentation License Contributors: User:Echion2, User:Moxfyre, User:Stannered

License 62 

License 

Creative Commons Attribution-Share Alike 3.0 Unported 

http:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/

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