diff --git a/mirror/files/sync-mirrors b/mirror/files/sync-mirrors
index 28a4d82..87a7498 100755
--- a/mirror/files/sync-mirrors
+++ b/mirror/files/sync-mirrors
@@ -50,6 +50,10 @@ while getopts "vhln" c ; do
             NOOP=" (DRY RUN)"
             EXTRA_OPTS="${EXTRA_OPTS} -n"
             ;;
+        *)
+            usage
+            exit 1
+            ;;
     esac
 done