SVN merge

I'll probably get laughed at by git/mercurial/darcs/whatever fanboys for even mentioning that I use subversion, but whatever. Just so I don't forget:

If, in subversion, you want to merge changes on a branch to the mainline, then the following is wrong:

svn merge http://svnserver/branches/foo/ http://svnserver/trunk/ .

Instead, you should use this:

svn merge http://svnserver/branches/foo@REV http://svnserver/branches/foo@HEAD .

With the current directory being a checkout from /trunk/, and REV being the revision where /branches/foo and /trunk started to diverge; that is, either the revision where the branch was made, or the one where they were brought back in sync with a merge in either direction.

Now hopefully I don't forget this for next time.