diff -ur charliecloud/test/docs-sane charliecloud-doc/test/docs-sane
--- charliecloud/test/docs-sane	2020-02-21 14:53:23.070000000 -0700
+++ charliecloud-doc/test/docs-sane	2020-05-11 10:47:07.440000000 -0600
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/python3
 # coding: utf-8
 
 # This script performs sanity checking on the documentation:
diff -ur charliecloud/test/make-perms-test charliecloud-doc/test/make-perms-test
--- charliecloud/test/make-perms-test	2019-12-23 11:39:36.220000000 -0700
+++ charliecloud-doc/test/make-perms-test	2020-05-11 10:56:41.790000000 -0600
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/python3
 
 # This script sets up a test directory for testing filesystem permissions
 # enforcement in UDSS such as virtual machines and containers. It must be run