diff --git a/ssl_checker.py b/ssl_checker.py
index b9c3756..4c9d76e 100644
--- a/ssl_checker.py
+++ b/ssl_checker.py
@@ -78,5 +78,6 @@ def clean_hostname(host):
 if __name__ == '__main__':
     if len(sys.argv) < 2:
         print('Usage: {} host1 [host2] [host3] ...'.format(sys.argv[0]))
+        sys.exit(0)
 
     show_result(sys.argv[1:])