Subversion (SVN) is a version control system used to maintain current and old versions of files such as source code, web pages and documents. It can be downloaded for free at http://subversion.tigris.org.The following are the current features listed on the official website:
- Most current CVS features.Subversion is meant to be a better CVS, so it has most of CVS’s features. Generally, Subversion’s interface to a particular feature is similar to CVS’s, except where there’s a compelling reason to do otherwise.
- Directories, renames, and file meta-data are versioned.Lack of these features is one of the most common complaints against CVS. Subversion versions not only file contents and file existence, but also directories, copies, and renames. It also allows arbitrary metadata (“properties”) to be versioned along with any file or directory, and provides a mechanism for versioning the `execute’ permission flag on files.
- Commits are truly atomic.No part of a commit takes effect until the entire commit has succeeded. Revision numbers are per-commit, not per-file; log messages are attached to the revision, not stored redundantly as in CVS.
- Apache network server option, with WebDAV/DeltaV protocol.Subversion can use the HTTP-based WebDAV/DeltaV protocol for network communications, and the Apache web server to provide repository-side network service. This gives Subversion an advantage over CVS in interoperability, and provides various key features for free: authentication, wire compression, and basic repository browsing.
- Standalone server option.Subversion also offers a standalone server option using a custom protocol (not everyone wants to run Apache 2.x). The standalone server can run as an inetd service, or in daemon mode, and offers basic authentication and authorization. It can also be tunnelled over ssh.
- Branching and tagging are cheap (constant time) operationsThere is no reason for these operations to be expensive, so they aren’t.Branches and tags are both implemented in terms of an underlying “copy” operation. A copy takes up a small, constant amount of space. Any copy is a tag; and if you start committing on a copy, then it’s a branch as well. (This does away with CVS’s “branch-point tagging”, by removing the distinction that made branch-point tags necessary in the first place.)
- Natively client/server, layered library design Subversion is designed to be client/server from the beginning; thus avoiding some of the maintenance problems which have plagued CVS. The code is structured as a set of modules with well-defined interfaces, designed to be called by other applications.
- Client/server protocol sends diffs in both directionsThe network protocol uses bandwidth efficiently by transmitting diffs in both directions whenever possible (CVS sends diffs from server to client, but not client to server).
- Costs are proportional to change size, not data sizeIn general, the time required for a Subversion operation is proportional to the size of the changes resulting from that operation, not to the absolute size of the project in which the changes are taking place. This is a property of the Subversion repository model.
- Choice of database or plain-file repository implementationsRepositories can be created with either an embedded database back-end (BerkeleyDB) or with normal flat-file back-end, which uses a custom format.
- Versioning of symbolic linksUnix users can place symbolic links under version control. The links are recreated in Unix working copies, but not in win32 working copies.
- Efficient handling of binary filesSubversion is equally efficient on binary as on text files, because it uses a binary diffing algorithm to transmit and store successive revisions.
- Parseable outputAll output of the Subversion command-line client is carefully designed to be both human readable and automatically parseable; scriptability is a high priority.
- Localized messagesSubversion uses gettext() to display translated error, informational, and help messages, based on current locale settings.
- Repository mirroringSubversion supplies a utility, svnsync for synchronizing (via either push or pull) a read-only slave repository with a master repository.
For those using Windows, you should also install TortoiseSVN. TortoiseSVN will allow you to easily interact with Subversion directly through Windows Explorer. While viewing files saved on your system, if you right-click the screen you’ll see some new commands that will allow you to connect to your SVN repository and add or checkout files.
In order to use TortoiseSVN you need to first install Subversion and set up a Subversion repository where the program can keep the copies of the documents that you’ve checked in. Subversion will then only save differences between versions of files that you’re storing in its repository. This is much more efficient than making copies of all files and ending up with multiple copies of the same files.
To create a repository, at a command prompt issue the following command:
svnadmin create –fs-type=fsfs
The directory specified above should be an empty directory!
The next step once everything is installed is to just play with it and figure out how to work it before using it on an actual project. Remember, always play before work!
