give help if no options are given
diff --git a/ebtablesu.c b/ebtablesu.c
index cd86783..1fed0c1 100644
--- a/ebtablesu.c
+++ b/ebtablesu.c
@@ -35,7 +35,8 @@
 		return -1;
 	} else if (argc == 1) {
 		fprintf(stderr, "At least one argument is needed.\n");
-		return -1;
+		print_help();
+		exit(0);
 	}
 
 	for (i = 0; i < argc; i++)