diff --git a/tools/update_revnum.py b/tools/update_revnum.py
index 9567c1f..7191114 100755
--- a/tools/update_revnum.py
+++ b/tools/update_revnum.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """ Change the revision number in Release.py """
 
 import os