diff --git a/contrib/nightly/test_tarball.sh b/contrib/nightly/test_tarball.sh
index f9db20d975..ce9549f550 100755
--- a/contrib/nightly/test_tarball.sh
+++ b/contrib/nightly/test_tarball.sh
@@ -19,7 +19,7 @@ vpath_arg="$5"
 
 # Set this to any value for additional output; typically only when
 # debugging
-debug=0
+debug=
 
 # do you want a success mail?
 want_success_mail=1