diff --git a/files/default/rebuild-iptables b/files/default/rebuild-iptables
index 0220086..24f46dc 100644
--- a/files/default/rebuild-iptables
+++ b/files/default/rebuild-iptables
@@ -1,4 +1,4 @@
-#!/usr/bin/ruby -w
+#!/usr/bin/env ruby -w
 
 #
 # rebuild-iptables.rb -- Construct an iptables rules file from fragments.