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 This article is not all-inclusive and may become out of date quickly.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

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.
• Licence: The licence model under which the software is licensed. These can be both free and paid licences
• 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	Revision IDs	Repository size	Network protocols
AccuRev	C++, Java	Changeset	Namespace	O(revisions)	custom
Aldon	C++, Java	Snapshot	Namespace	O(revisions)	custom
CA Software Change Manager	C, C++, Java, HTML	Changeset and Snapshot	Namespace	O(patch)	HTTP, custom (TCP)
Bazaar	Python, Pyrex, C[6]	Snapshot	Pseudorandom	O(patch)	HTTP, SFTP, FTP, custom, custom over ssh, email bundles[7], WebDAV (with plugin)
ClearCase	C	Changeset	Namespace	O(patch)	HTTP, custom (CCFS), custom (MVFS filesystem driver)
CVS	C	Changeset	Namespace	O(patch)	pserver[68], ssh
Perforce	c++, c	Changeset	Namespace	O(patch)	custom
StarTeam	C, Java	Snapshot	MD5 hashes	O(revision)	custom, TCP/IP
Subversion	C	Changeset and Snapshot	Namespace	O(patch)	custom over ssh, HTTP and SSL (using WebDAV), custom (svnserve)
Surround SCM	C++	Changeset	Namespace	O(patch)	custom
Team Foundation Server	C++ and C#	Changeset	Namespace	O(patch)	SOAP over HTTP or HTTPS
Vault	C#	Changeset	?	O(patch)	HTTP, HTTPS
Visual SourceSafe	C	Snapshot	Namespace?	O(changes)?	None, but can access repository files through a "share"
Software	Programming language	History model	Revision IDs	Repository size	Network protocols

Table Explanation

• Software: The name of the application that is described.
• Programming Language: The coding language in which the application is being developed
• 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.
• 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).
• Repository size: describes the growth-rate of the repository as changes are committed. O(patch) means that it grows as the size of the patches between revisions, while O(revisions) means that it grows as the size of each revision checked in.
• Network protocols: lists the protocols used for synchronization of changes.

Features

Table Explanation

• Software: The name of the application that is described.
• 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.
• International Support: Indicates if the software has support for multiple language environments and operating system

Basic Commands

Software	branch init with/without repository	repository init	clone	pull	push	fetch	git-style branch	git-style checkout	checkout	update	add	remove	move	copy	merge	commit	revert	generate bundle file	rebase
Bazaar	init	init-repository / init-repo	branch / clone / get	pull	push	No	create-local-branch, list-local-branches, remove-local-branch (bzr-local-branches plugin)	switch-local-branch (bzr-local-branches plugin)	checkout / co	update / up	add	remove / rm	move / mv / rename	No	merge	commit / ci / checkin	revert	send	rebase (rebase plugin)
Git	init	?	clone	pull	push	fetch	branch	checkout	No	No	add	rm	mv	No	merge	commit	revert	bundle	rebase
SVN	(mkdir+svn add)	svnadmin create	svn copy / cp (in same repository only)	No	No	No	No	No	svn checkout / co	svn update / up	svn add	svn delete / del / remove / rm	svn move / mv / rename / ren	svn copy / cp	svnmerge merge	svn commit / ci	svn revert	No	???
Mercurial	init	?	clone	pull	push	fetch (fetch extension)	bookmarks extension	update / up / checkout / co	No	No	add	remove / rm	rename / mv	copy	merge	commit	revert	bundle	rebase (rebase extension)
Software	branch init with/without repository	repository init	clone	pull	push	fetch	git-style branch	git-style checkout	checkout	update	add	remove	move	copy	merge	commit	revert	generate bundle file	rebase

• Software: The name of the application that is described.
• 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 checkin/checkout files.