diff --git a/tests/diff/comparediffs b/tests/diff/comparediffs
index 0a5c3c4..358530b 100755
--- a/tests/diff/comparediffs
+++ b/tests/diff/comparediffs
@@ -1,3 +1,4 @@
+#!/bin/bash
 if [ "$#" != "2" ]; then
 	echo "Please supply the addresses of two SOCKS proxies:"
 	echo "compare host1:port1 host2:port2"