diff --git a/build-tmp-XXX b/build-tmp-XXX
index b8fcd6c..d2d2dd3 100755
--- a/build-tmp-XXX
+++ b/build-tmp-XXX
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/bash -x
 set -e
 
 self=`realpath $0`