diff --git a/build.sh b/build.sh
index 5a426b4..d709949 100755
--- a/build.sh
+++ b/build.sh
@@ -1,3 +1,5 @@
+#!/bin/bash
+
 if [ -z ${NGINX_PATH+x} ]; then
   echo "Please set the NGINX_PATH variable";
   exit