diff --git a/script/cosmasvc2koralquery b/script/cosmasvc2koralquery
index 65a62dd..daed10b 100755
--- a/script/cosmasvc2koralquery
+++ b/script/cosmasvc2koralquery
@@ -32,7 +32,7 @@
 )
 or die("Error in command line arguments\n");
 
-if ($cmd ne 'def' && $cmd ne 'list') {
+if (!$cmd || ($cmd ne 'def' && $cmd ne 'list')) {
   print <<'HELP';
 Convert a list of C2 VC definitions or a single definition into
 KoralQuery VCs.