About Linux GNU Screen command


Screen is a terminal multiplexer. It means that you can start a screen session and then open any number of windows (virtual terminals) inside that session. Processes running in Screen will continue to run when their window is not visible even if you get disconnected.

It supports a scrolback history buffer for each virtual terminal and it is possible to move text regions between windows.

Linux screen command offers you to open several separate terminal instances inside a one single terminal window manager.

The screen application is very useful, if you are dealing with multiple programs from a command line interface.

Screen is started from the command line just like any other command:

$ screen

Screen functions just like a normal shell except for a few special characters.


Control Command


Screen uses the command “Ctrl-a” as a signal to send commands to screen instead of the shell.
Key bindings are the commands the screen uses after you press “Ctrl-a”. You can reconfigure these keys to your liking using a .screenrc file.

Features


ü  Create multiple windows inside a Screen session
ü  Use multiple shell windows from just one SSH session
ü  Keep a shell session active even when there are network disturbances
ü  Manage connections to shell from multiple locations
ü  Keep a long running session alive even after exiting a shell session
ü  You can detach from the screen session at any time
ü  You can reattach or reconnect to a Linux Screen
ü  You can list screens
ü  Switch between windows
ü  Log your screen output
ü  Lock screen session

Alerts about activity or inactivity


Screen can monitor a window for activity or inactivity. This is great for long operations and computations, when you wait long for output.

You can use “Ctrl-a” “M” to look for activity. Screen will then flash an alert at the bottom of the page when output is registered on that screen.

You can also monitor for inactivity.

If you’re waiting for some long operation to complete, you can be notified when there is no more output. This is a signal for that job is done. To monitor for silence or no output use “Ctrl-a” “_”.

Terminating screen session


Once we are done with the screen sessions, we can terminate it (and start it again later to attach to previous sessions) with the combination of “Ctrl-a” key followed by “k”.

If you frequently remote into your Linux servers, and you want to make sure to not lose your command line work due to a questionable network connection, screen is a must-use program. To learn more about what this can do, issue the command man screen and read through the manual page.

For more info:- check ubuntu version 

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