Significant changes in the library often cannot be developed all at once. In a case like this, one can create a development branch in the subversion repository into which one can check in all necessary changes and from which one can merge the final set of changes into the main development line once ready. The svn program can be used to keep your branch up-to-date with the trunk.
Creating a branch works through the following steps:
$ svn copy https://svn.dealii.org/trunk/ https://svn.dealii.org/branches/new-branch-name
$ svn switch https://svn.dealii.org/branches/new-branch-nameThis command assumes you are in the top level directory, the one containing deal.II and tests
$ svn merge ^/trunkThis command will only run if you have no local changes in your working directory for the branch, and will modify all of your files by merging the changes made on mainline. If there are no conflicts that need to be resolved, you can simply commit the result.