-leading=`expr "refs/heads/$branchname" : '\(.*\)/'` &&
-mkdir -p "$GIT_DIR/$leading" &&
-echo $rev > "$GIT_DIR/refs/heads/$branchname"
+if [ -e "$GIT_DIR/refs/heads/$branchname" ]
+then
+ if test '' = "$force"
+ then
+ die "$branchname already exists."
+ elif test "$branchname" = "$headref"
+ then
+ die "cannot force-update the current branch."
+ fi
+fi
+if test "$create_log" = 'yes'
+then
+ mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$branchname")
+ touch "$GIT_DIR/logs/refs/heads/$branchname"
+fi
+git update-ref -m "branch: Created from $head" "refs/heads/$branchname" $rev