diff --git a/unix/vncserver b/unix/vncserver
index 7cde166..f3ad686 100755
--- a/unix/vncserver
+++ b/unix/vncserver
@@ -805,6 +805,8 @@ sub DetectDisplayNumberFromCliArgs {
       }
    } elsif (($ARGV[0] !~ /^-/) && ($ARGV[0] !~ /^\+/)) {
       &Usage();
+   } else {
+      $displayNumber = &GetLowestAvailableDisplayNumber();
    }
 }