Subversion (svn)
Subversion is an amazing version control system that can be applied in all sorts of contexts including development projects.
The full manual can be found here: http://svnbook.red-bean.com/
Subversion itself can be found at the subversion project pages: http://subversion.tigris.org/
Outputting a list of changed or new filenames between two branches or revisions and using a shell script ot export these files into an identical directory strcuture