diff --git a/docs/examples/manual-operation-docs/how_to_persistent_iptables_rules_with_debian_9.mkd b/docs/examples/manual-operation-docs/how_to_persistent_iptables_rules_with_debian_9.mkd
index 94ad473..b89543a 100644
--- a/docs/examples/manual-operation-docs/how_to_persistent_iptables_rules_with_debian_9.mkd
+++ b/docs/examples/manual-operation-docs/how_to_persistent_iptables_rules_with_debian_9.mkd
@@ -45,5 +45,5 @@ Note: User iptables-save/ip6tables-save command, save file must is above file na
 ## Well-done 
 Iptables rules would auto restore iptables rules when Operation system restart, or manual to exec following command:
 ```
-$ systemctl restart  netfilter-persistent
+$ sudo systemctl restart  netfilter-persistent
 ```