diff --git a/systemtests/scripts/cleanup b/systemtests/scripts/cleanup
index ee9fdc1b9d2..aff6f223f3d 100755
--- a/systemtests/scripts/cleanup
+++ b/systemtests/scripts/cleanup
@@ -1,8 +1,8 @@
 #!/bin/sh
+set -u
 
 . ./environment
 
-
 rm -rf ${tmp}/*
 rm -rf ${logdir}/*.log
 rm -rf ${working}/*.bsr ${working}/log*.sd