Documentation for Subversion (sometimes referred to as "SVN") is available here.
Anonymous Subversion Access
This tool/resource group's SVN repository can be checked out through anonymous access with the following command(s).
svn checkout https://www.nitrc.org/svn/shapetools
Please note: You will still need to use your NITRC login information though you do not have to be a member of ShareTools.
Developer Subversion Access via DAV
Only tool/resource developers can access the SVN tree via this method. Substitute developername with the proper values. Enter your site password when prompted.
Browsing the SVN tree gives you a great view into the current status of this tool/resource group's code. You may also view the complete histories of any file in the repository.