diff --git a/command/screen.md b/command/screen.md
index 5f2816f085..b066dd67c9 100644
--- a/command/screen.md
+++ b/command/screen.md
@@ -166,14 +166,14 @@ Screen默认会为窗口命名为编号和窗口中运行程序名的组合，
 
 此外，这里再介绍另外一种快速杀死一个Screen会话的命令：
 
-```
+```shell
 [root@TS-DEV ~]# screen -ls   #列出存在的会话
 [root@TS-DEV ~]# screen -XS "会话id或者名称" quit
 ```
 
 **示例：**
 
-```
+```shell
 [root@TS-DEV ~]# screen -ls
 There are screens on:
 	11235.test	(01/25/2021 03:35:31 PM)	(Detached)