如果想杀死一个已经detached的screen会话，可以使用以下命令：

screen -X -S [session # you want to kill] quit

root@leco:~# screen -lsThere are screens on:17708.pts-4.leco(06/15/2017 02:39:09 PM)(Attached)14814.pts-2.leco(06/15/2017 02:22:52 PM)(Detached)14795.pts-2.leco(06/15/2017 02:22:44 PM)(Detached)14442.pts-2.leco(06/15/2017 02:22:31 PM)(Detached)4 Sockets in /var/run/screen/S-root.

root@leco:~# screen -X -S 17708 quitroot@leco:~# screen -lsThere are screens on:14814.pts-2.leco(06/15/2017 02:22:52 PM)(Detached)14795.pts-2.leco(06/15/2017 02:22:44 PM)(Detached)14442.pts-2.leco(06/15/2017 02:22:31 PM)(Detached)3 Sockets in /var/run/screen/S-root.