diff --git a/README.md b/README.md
index 2b359ee..a914fdd 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ https://github.com/zhaojh329/rttys/releases
 
 ## Run in background (Ubuntu)
 
-	update-rc.d rttys defaults
+	sudo update-rc.d rttys defaults
     sudo /etc/init.d/rttys start
 
 # Contributing
diff --git a/README_ZH.md b/README_ZH.md
index 63c0a51..0dd661f 100644
--- a/README_ZH.md
+++ b/README_ZH.md
@@ -44,7 +44,7 @@ https://github.com/zhaojh329/rttys/releases
 
 ## 后台运行 (Ubuntu)
 
-	update-rc.d rttys defaults
+	sudo update-rc.d rttys defaults
     sudo /etc/init.d/rttys start
 
 # 贡献代码