diff --git a/git-rebase.sh b/git-rebase.sh
index 2cf73b88e8..45f187bdbf 100755
--- a/git-rebase.sh
+++ b/git-rebase.sh
@@ -348,6 +348,9 @@ do
 		shift
 		break
 		;;
+	*)
+		usage
+		;;
 	esac
 	shift
 done