diff --git a/periodic/12h/certbot b/periodic/12h/certbot
old mode 100644
new mode 100755
index 2893ca5..c931b6e
--- a/periodic/12h/certbot
+++ b/periodic/12h/certbot
@@ -1 +1,3 @@
+#!/usr/bin/env sh
+
 sleep "$RANDOM" && exec certbot-ovh.sh