screen: commonly used operation and commands

https://linuxize.com/post/how-to-use-linux-screen/

https://www.mattcutts.com/blog/a-quick-tutorial-on-screen/

list out the created screens:
screen -ls

create a new screen:
screen -S screen_name

reattach to a existing screen:
screen -r screen_need_to_be_attached

General commands:
every screen command starts from ctrl+a, session and window are two different terms, in one session, it can include several windows.

keys	introductions
ctrl+a d	detach from current window
ctrl+a k	kill current window
ctrl+a Shift	split window vertically, this is not supported in GNU version <4.01
ctrl+a S	spllit window horizontally
ctrl+a TAB	switch between the splitted windows
ctrl+a Q	unsplit window
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