diff --git a/issue-or-renew-certs-for-dsm.sh b/issue-or-renew-certs-for-dsm.sh
index a89decb..656df21 100644
--- a/issue-or-renew-certs-for-dsm.sh
+++ b/issue-or-renew-certs-for-dsm.sh
@@ -1,3 +1,5 @@
+#!/bin/bash
+
 SCRIPT_PATH="$(dirname $(readlink -f $BASH_SOURCE))"
 DOMAIN_FILES_PATH="$SCRIPT_PATH/domains"
 ACMESH_CONTAINER_DATA_PATH="$SCRIPT_PATH/data"