Downloading Source Trees 101
If you’ve been using open source for a good length of time, you’ve probably needed a feature or bug fix that’s only available in the development tree of a open source project. For example, if you want to use PostgreSQL with RTG, you have to download and build the developers’ latest code. (Those exact instructions can be found in the March 2005 “Tech Support” column, located online at http://www.linux-mag.com/2005-03/tech_01.html/.)
Unlike stable releases, which are usually conveniently available for download as either source tarballs or binary packages, development code is often only available from a project’s source code repository. Typically, a repository is either a CVS (http://www.nongnu.org/cvs/) or Subversion (SVN, http://subversion.tigris.org/) repository.
Here, let's see how to use CVS and SVN to access the development tree of a few notable projects.