diff --git a/script/korapxml2krill b/script/korapxml2krill
index acf8d63..c264436 100644
--- a/script/korapxml2krill
+++ b/script/korapxml2krill
@@ -359,7 +359,7 @@
 
 
 # Start serial processing
-if ($cmd eq 'serial') {
+if ($cmd && $cmd eq 'serial') {
 
   if ($output && (!defined($to_tar)) && (!-e $output || !-d $output)) {
     $log->error("Directory '$output' does not exist.");