How to undo a commit (or uncommit) in Subversion.
The svn revert command can not be used as it only reverts local changes, ie. restores all files to the checked out revision.
Instead, here's how to do it. Use the svn merge command. It usually merges revisions from one repository into another. However, it can be used to do the opposite: unmerging.
svn merge -c X SOURCE merges commit X from SOURCE repository to working copy. If X is negative it will be regarded as an inverse merge and the commit removed instead of added.
So, the following command reverts revision 34 in the working copy.
svn merge -c -34 .
Don't forget to commit.