[svn] How do I revert an SVN commit?

I tried the above, (svn merge) and you're right, it does jack. However

svn update -r <revision> <target> [-R]

seems to work, but isn't permanent (my svn is simply showing an old revision). So I had to

mv <target> <target backup>
svn update <target>
mv <target backup> <target>
svn commit -m "Reverted commit on <target>" <target>

In my particular case my target is interfaces/AngelInterface.php. I made changes to the file, committed them, updated the build computer ran the phpdoc compiler and found my changes were a waste of time. svn log interfaces/AngelInterface.php shows my change as r22060 and the previous commit on that file was r22059. So I can svn update -r 22059 interfaces/AngelInterface.php and I end up with code as it was in -r22059 again. Then :-

mv interfaces/AngelInterface.php interfaces/AngelInterface.php~
svn update interfaces/AngelInterface.php
mv interfaces/AngelInterface.php~ interfaces/AngelInterface.php
svn commit -m "reverted -r22060" interfaces/AngelInterface.php

Alternatively I could do the same thing on a directory, by specifying . -R in place of interfaces/AngelInterface.php in all the above.