Basic Linux Screen Commands

Command line

Linux screen is a very useful tool that comes pre-installed on almost all server distributions. So why not use it to make your lives a little better?

Why use screen?

Screen lets you do the following:

  • Run a long running process without maintaining an active shell session
  • Use multiple shell windows from a single SSH session
  • Keep a shell active even after network disconnects

These are just some of the most popular and basic features of screen and what will be couvered in this article

Running screen

Once installed, starting screen is as simple as invoking it just like any other command

$ screen

This will land you in a screen instance.

Reattaching to a running screen instance

$ screen -r

If there are multiple screen instances running, the command will list all running instances instead of attaching to an instance like so

$ screen -r
There are several suitable screens on:
31917.pts-5.ubuntu      (Detached)
31844.pts-0.ubuntu      (Detached)
Type "screen [-d] -r [pid.]tty.host" to resume one of them.

In this case run the same command with the screen ID like so:

$ screen -r 31917.pts-5.ubuntu

Reattaching to a running screen instance after a network issue

Sometimes, after a network disconnect, screen might error you out when trying to reattach

$ screen -r 31844.pts-0.ubuntu
There is a screen on:
    31917.pts-5.ubuntu (09/09/2018 05:29:24 AM)    (Attached)
There is no screen to be resumed matching 31844.pts-0.ubuntu.

In this case, just use the -d flag

$ screen -r -d 31844.pts-0.ubuntu

Basic commands, once inside a screen

Screen uses the command Ctrl-a that’s the control key and a lowercase a as a signal to send commands to screen instead of the shell.

Ctrl-athen ?

screen help page

Ctrl-athen c

creates a new window

Ctrl-athen n

This command switches you to the next window

Ctrl-athen p

This command switches you to the previous window

Ctrl-athen d

This command switches you to detach from a window, This will land you on your shell but your windows are still there and you can always reattach to them later.

exit

This command closes the screen window. You have to close all screen windows to terminate the session.