Linux Screen in Virtual Machine

3 min readSep 21, 2020

This blog is taken from https://linuxize.com. This is addition to my own cluster of information that I will be using in daily life.

Have you ever faced the situation where you perform a long-running task on a remote machine, and suddenly your connection drops, the SSH session is terminated, and your work is lost. Well, it has happened to all of us at some point, hasn’t it? Luckily, there is a utility called screen that allows us to resume the sessions.

Introduction

Screen or GNU Screen is a terminal multiplexer. In other words, 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.

Install Linux GNU Screen

The screen package is pre-installed on most Linux distros nowadays. You can check if it is installed on your system by typing:

screen --versionScreen version 4.06.02 (GNU) 23-Oct-17

If you don’t have screen installed on your system, you can easily install it using the package manager of your distro.

Install Linux Screen on Ubuntu and Debian

sudo apt updatesudo apt install screen

Install Linux Screen on CentOS and Fedora

sudo yum install screen

Starting Linux Screen

To start a screen session, simply type screen in your console:

screen

This will open a screen session, create a new window, and start a shell in that window.

Now that you have opened a screen session, you can get a list of commands by typing:

Ctrl+a ?

Starting Named Session

Named sessions are useful when you run multiple screen sessions. To create a named session, run the screen command with the following arguments:

screen -S session_name

It’s always a good idea to choose a descriptive session name.

Working with Linux Screen Windows

When you start a new screen session, it creates a single window with a shell in it.

You can have multiple windows inside a Screen session.

To create a new window with shell type Ctrl+a c, the first available number from the range 0...9 will be assigned to it.

Below are some most common commands for managing Linux Screen Windows:

Ctrl+a c Create a new window (with shell)
Ctrl+a " List all window
Ctrl+a 0 Switch to window 0 (by number )
Ctrl+a A Rename the current window
Ctrl+a S Split current region horizontally into two regions
Ctrl+a | Split current region vertically into two regions
Ctrl+a tab Switch the input focus to the next region
Ctrl+a Ctrl+a Toggle between the current and previous region
Ctrl+a Q Close all regions but the current one
Ctrl+a X Close the current region

Detach from Linux Screen Session

You can detach from the screen session at any time by typing:

Ctrl+a d

The program running in the screen session will continue to run after you detach from the session.

Reattach to a Linux Screen

To resume your screen session use the following command:

screen -r

In case you have multiple screen sessions running on your machine, you will need to append the screen session ID after the r switch.

To find the session ID list the current running screen sessions with:

screen -lsThere are screens on:
    10835.pts-0.linuxize-desktop   (Detached)
    10366.pts-0.linuxize-desktop   (Detached)
2 Sockets in /run/screens/S-linuxize.

If you want to restore screen 10835.pts-0, then type the following command:

screen -r 10835

Basic Linux Screen Usage

Below are the most basic steps for getting started with screen:

On the command prompt, type screen.
Run the desired program.
Use the key sequence Ctrl-a + Ctrl-d to detach from the screen session.
Reattach to the screen session by typing screen -r

Screen user manual: https://www.gnu.org/software/screen/manual/screen.html