How to use screen command in Linux

--> To open a new screen:

#screen -S "Screenname"
Eg.: 

#screen -S "testscreen"

--> To deattach the screen:

Cntrl+A then D   //it will run after detach also
--->    Ctrl-a followed by k: close the current windows (kill)

--> To list the screen:

screen -list

--> To reattach the screen:

screen -r ScreenID------- From screen -list



Example:

# screen -S "testscreen"   // create screen name testscreen
Agent pid 21981

Now we are running small test script in "testscreen".

#/test.sh >>data.txt &  //ran script test.sh to append hello and date/time in data.txt
[1] 4917

Cntrl+A then D   //it will detach

[detached]
# screen -list   //list currently running screen
There is a screen on:
        3015.testscreen (Detached)
1 Socket in /var/run/uscreens/S-alhatul.

Reattch screen using following command
screen -r ScreenID
#screen -r 3015   //reattach screen
Agent pid 21981

output of screen command

Output of test.sh
===data.txt ======

#cat data.txt
hello
Fri Aug 30 15:21:00 CEST 2019
hello
Fri Aug 30 15:21:02 CEST 2019
hello
Fri Aug 30 15:21:04 CEST 2019
hello

Ctrl-a followed by k:
It will terminate current screen session.

#screen -list
No Sockets found in /var/run/uscreens/S-alhatul.