diff --git a/files/automysqlbackup_post_script b/files/automysqlbackup_post_script
index 35215b2..a551ed7 100644
--- a/files/automysqlbackup_post_script
+++ b/files/automysqlbackup_post_script
@@ -1,3 +1,5 @@
+#!/bin/sh
+
 source /etc/default/automysqlbackup
 
 # available variables: