diff --git a/README.md b/README.md
index 85f9aaf..d327384 100644
--- a/README.md
+++ b/README.md
@@ -10,5 +10,5 @@ Execute `sync.sh` to copy scripts on the server.
 Add this line into the host crontab with `crontab -e`.
 ```
 # Backup volumes every days at 4am
-0 4 * * * /usr/local/bin/vol-backup-all
+0 4 * * * root /bin/bash /usr/local/bin/vol-backup-all
 ```