diff --git a/check_docker.sh b/check_docker.sh
index 0c541578964748b82f15e0ffb882c00bc1f6181c..3273d28519a7fa30015699d5cd5a769af73803cc 100755
--- a/check_docker.sh
+++ b/check_docker.sh
@@ -41,8 +41,8 @@ while [[ $# -gt 0 ]]; do
             ;;
 
         *)
-            echo "Error while parsing argument '$1'."
-            exit 1
+            echo "err: failed to parse argument '$1'."
+            exit 2
             ;;
     esac
 done