Research:Svn documentation
Subversion is a source control program much like cvs or rcs.
It works by keeping track of a main copy of a codebase known as the repository. One checks out a working copy into thier own working directory or codebase. As changes are made to different files in the codebase they are first updated from the repository so that any conflicts can be resolve between conflicting code that some one else may have committed during the time that the changes were made. Next they commit the code to the repository so that others can get thier changes.
To check out a copy of the repository code base into your working directory for the first time: svn co svn+ssh://bme-earth/subversion/crs-param-cpp
To update your existing checked out working directory: svn update
To commit your changes: svn commit -m"message" where message is a comment on this revision.
Link to subversion manual