diff --git a/scripts/cnode-helper-scripts/mithril-client.sh b/scripts/cnode-helper-scripts/mithril-client.sh
index 70cd3189b..95da403b9 100755
--- a/scripts/cnode-helper-scripts/mithril-client.sh
+++ b/scripts/cnode-helper-scripts/mithril-client.sh
@@ -176,6 +176,10 @@ while getopts :duh opt; do
       usage
       exit 1
       ;;
+    *)
+      usage
+      exit 1
+      ;;
   esac
 done
 
diff --git a/scripts/cnode-helper-scripts/mithril-relay.sh b/scripts/cnode-helper-scripts/mithril-relay.sh
index c395c232d..6c104fddf 100755
--- a/scripts/cnode-helper-scripts/mithril-relay.sh
+++ b/scripts/cnode-helper-scripts/mithril-relay.sh
@@ -208,6 +208,10 @@ while getopts :dlh opt; do
       usage
       exit 1
       ;;
+    *)
+      usage
+      exit 1
+      ;;
     esac
 done