$ svn add trunk/*
$ svn stat
$ svn cp trunk tags/{TAG}
$ svn ci -m "comment" --username your_username --password your_password
svn delete https://plugins.svn.wordpress.org/{PLUGIN}/tags/{TAG} -m "comment"
$ svn add trunk/*
$ svn stat
$ svn cp trunk tags/{TAG}
$ svn ci -m "comment" --username your_username --password your_password
svn delete https://plugins.svn.wordpress.org/{PLUGIN}/tags/{TAG} -m "comment"