+if [ -e "$GIT_DIR/refs/heads/$branchname" ]
+then
+ if test '' = "$force"
+ then
+ die "$branchname already exists."
+ elif test "$branchname" = "$headref"
+ then
+ die "cannot force-update the current branch."
+ fi
+fi
+git update-ref "refs/heads/$branchname" $rev
+