刚刚才注意，默认情况下rhel6 是不安装screen命令的：

[root@rhel63single yum.repos.d]# yum install screen
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
Updating certificate-based repositories.
Unable to read consumer identity
rhel-source                                                                                                                          | 4.0 kB     00:00 ... 
rhel-source-beta                                                                                                                     | 4.0 kB     00:00 ... 
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package screen.x86_64 0:4.0.3-16.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

============================================================================================================================================================
 Package                           Arch                              Version                                   Repository                              Size
============================================================================================================================================================
Installing:
 screen                            x86_64                            4.0.3-16.el6                              rhel-source                            494 k

Transaction Summary
============================================================================================================================================================
Install       1 Package(s)

Total download size: 494 k
Installed size: 795 k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : screen-4.0.3-16.el6.x86_64                                                                                                                          1/1 
Installed products updated.
  Verifying  : screen-4.0.3-16.el6.x86_64                                                                                                                          1/1 

Installed:
  screen.x86_64 0:4.0.3-16.el6                                                                                                                                         

Complete!
[root@rhel63single yum.repos.d]# which screen
/usr/bin/screen
[root@rhel63single yum.repos.d]# 

一、screen 的建立

[root@rhel63single ~]# screen -ls
No Sockets found in /var/run/screen/S-root.

[root@rhel63single ~]# 
[root@rhel63single ~]# 
[root@rhel63single ~]# screen -dmS lei1
[root@rhel63single ~]# screen -ls
There is a screen on:
        5786.lei1       (Detached)
1 Socket in /var/run/screen/S-root.

[root@rhel63single ~]#
其中：5786是linux的ospid。lei1是会话的名称。

二、screen 的进入

[root@rhel63single ~]# screen -r lei1

三、暂时退出某个screen 的session ：先按ctrl ，再按小写的a，再按小写的d

[root@rhel63single ~]# 


            
[detached]
[root@rhel63single ~]# 

四、若是本来就在该session中，再使用screen -r lei1命令时的提示：

[root@rhel63single ~]# screen -r lei  或者用screen -r 5786
There is a screen on:
        5786.lei1       (Attached)
There is no screen to be resumed matching lei.
[root@rhel63single ~]# 

五、状态解释：

[root@rhel63single ~]# screen -dmS lei2
[root@rhel63single ~]# 
[root@rhel63single ~]# 
[root@rhel63single ~]# 
[root@rhel63single ~]# screen -ls
There are screens on:
        5850.lei2       (Detached)---->挂起状态，无终端在连接会话
        5786.lei1       (Attached)---->有终端在连接会话。
2 Sockets in /var/run/screen/S-root.

[root@rhel63single ~]# 

六、永久退出screen中的本session

[root@rhel63single ~]# exit
                           exit


                        
[screen is terminating]
[root@rhel63single ~]# screen -ls
There is a screen on:
        5850.lei2       (Detached)
1 Socket in /var/run/screen/S-root.

 

七、检查screen中的其他session的来源ip：