ubuntu中screen的使用
screen概念：
“screen命令类似于“虚拟桌面”的概念,可以启动一个Linux下的虚拟桌面,在其中可以和普通终端一样执行各种命令。”
screen可以实现当前窗口和任务的分离，即使在离线状态下，我们在服务器上的程序仍能在后台运行。重新登录到服务器后，读取窗口进程，就能连接到对应的程序窗口。
一、需求背景：
1）ubuntu环境中需要同时启动前端和后端，但是两者不能同时在一个窗口中运行；
2）如果ubuntu环境过一段时间不使用，会被自动退出，此时启动的进程也被终止。
二、业务实现
1.检查ubuntu中是否有screen，没有则安装
sudo apt-get install screen
2.安装完成之后，我们还是进入到上次我们创建的文件夹
screen -ls #显示当前用户所拥有的scree详情
sudo su
screen -S myserver #1.创建一个名为 myserver的screen
conda activate web
cd MyService/myserver/
python myserver.py #在窗口myserver中运行后端python程序
Ctrl+a d #退出当前screen
screen -S myclient #2.创建一个名为myclient 的screen
conda activate web
cd MyService/myclient/
npm run serve #在窗口lin中运行前端程序
Ctrl+a d
screen -ls #显示当前用户所拥有的scree详情
screen -r myclient #进入窗口myclient
screen -r myserver #进入窗口myserver
Ctrl+a d #退出当前窗口
这样，开两个screen窗口分别运行前端和后端，即使关掉xshell之后网站也会在后台继续跑 不会被关闭啦。
三、screen常用命令总结
Ctrl+a ? 显示所有键绑定信息
Ctrl+a w 显示所有窗口列表
Ctrl+a C-a 切换到之前显示的窗口
Ctrl+a c 创建一个新的运行shell的窗口并切换到该窗口
Ctrl+a n 切换到下一个窗口
Ctrl+a p 切换到前一个窗口(与C-a n相对)
Ctrl+a 0..9 切换到窗口0..9
Ctrl+a a 发送 C-a到当前窗口
Ctrl+a d 暂时断开screen会话
Ctrl+a k 杀掉当前窗口
Ctrl+a [ 进入拷贝/回滚模式
1)List all screen sessions of current user
#screen -ls
2)To see all screen sessions on a specific machine
#ls -laR /var/run/screen/
3)To see all commands or parameters on screen.
Ctrl + a, Then Press ?
4)Open a new screen session
#screen
5)Detach/Exit from a screen session
Ctrl + a, Then Press d
6)Kill a screen session
Ctrl + a, Then Press Shift + k
7)Reattach to a screen session
#screen -r session_id_or_name
8)How to create multiple screen window/tab in a screen session
Ctrl + a, Then Press c
9)How to move to next screen window/tab in a screen session
Ctrl + a, Then Press n
10)How to move to previous screen window/tab in a screen session
Ctrl + a, Then Press p
11)How to goto n'th screen window/tab
Ctrl + a, Then Press '
12)How to list name of all screen windows/tabs and select from there
Ctrl + a, Then Press Shift + '
13)How to switch to screen window/tab 0 - 9
Ctrl + a, Then Press 0 -9
14)
How to Toggle to the window/tab displayed previously
Ctrl + a, Then Ctrl + a again
15)How to change the name of screen window/tab
Ctrl + a, Then Press Shift + a
16)How to clear a screen window/tab
Ctrl + a, Then Press Shift + c
17)How to Kill all windows and terminate screen
Ctrl + a, Then Press \
screen -ls
18)How to lock a screen session
Ctrl + a, Then Press x
19)How to log a screen session
You will find screenlog.0 file in your home directory.
Ctrl + a, Then Press Shift + h
or
#screen -L (Capital L)
20)reattach to a specific window/tab in a screen session
#screen -r session_id_or_name -p tab_num_or_name
21)If a session is running, then reattach. If necessary detach and logout remotely first. If it was not running create it and notify the user.
#screen -D -R
22)How to create new screen session and specify a meaningful name for the session.
#screen -S session_name
23)Howto Attach to a not detached screen session.
#screen -x
24)How to split screen
a)
Split the Window
Horizontally
Ctrl + a, Then Press Shift + s
or
Vertically
Ctrl + a, Then Press Shift + \
b)
Switch between spilted windows
Ctrl + a, Then Press Tab
or
Ctrl + a, Then Type :focus
* Here :focus is a command
c)
In the spited window use following command to open existing session
Ctrl + a, Then Press 0-9
or
Ctrl + a, Then Press n or p
or
Ctrl + a, Then Press Shift + '
or
Ctrl + a, Then Presss c
d)
Resize a splitted window/region
Ctrl + a, Then Type :resize 25
* Here :resize is a command
e)
Remove current splitted window/region
Ctrl + a, Then Type :remove
* Here :remove is a command
or
Ctrl + a, Then Press Shift + x
f)
Remove all spiltted windows/regions except the current one.
Ctrl + a, Then Type :only
* Here :only is a command
or
Ctrl + a, Then Press Shift +q
g)
Change color of split bar (border)
http://michael-prokop.at/computer/config/.screenrc
#vim ~/.screenrc
sorendition 10 74
h)
Close the screen and all regions
Ctrl + a, Then Press \
25)How to rename an existing session
screen -ls
screen -x old_session_name
Ctrl + a, Then Type :sessionname new_session_name
*Here :sessionname is a command