How to install and use Screen in Linux

Have you ever been in the following situation - you are working with the command line and you are jumping between multiple tasks and windows at the same time?
If you've been, you might have experienced the frustration of losing track of where you are. Luckily for us, there's a tool that can make dealing with multiple tasks way easier: GNU Screen.

GNU Screen is a terminal multiplexer. It lets you create and manage multiple terminal sessions within a single window. With Screen, you can run several shell sessions, detach them, and later reattach them from anywhere, even after logging out and logging back in. You can also split the terminal window into multiple regions and run different commands in each one.

In this tutorial, you will get familiar with GNU Screen and some of its features.

Installation

Screen is pre-installed on most Linux distributions. You can check this by typing:

screen --version

If it is pre-installed, the output should be similar to the one below.

Screen version 4.08.00 (GNU) 05-Feb-20

If not, you can easily install via the following commands:

For Debian/Ubuntu

sudo apt install screen

For CentOS/Fedora/Alma/Rocky

sudo yum install screen

Starting Screen

Screen can be started by simply typing "screen" in your console.

screen

The command opens a screen session, creates a new window, and starts a shell in it.

A named session can be started by running:

screen -S session_name

Common Commands

For your convenience, Screen relies on keyboard commands. They consist of a Control + a followed by one other character.
All commands that are bound to lower-case letters are also bound to their control character counterparts.
All commands below, which start with a Ctrl+a , are keyboard commands. These can be submitted only through sessions.

Start a new session

screen

Invokes screen

screen -ls

List all available screen sessions

Reattach to a session

screen -r

Reattaches to the last active Screen session.

screen -r session_id

Reattaches to a specific Screen session.
The id of the active sessions can be viewed by listing the sessions with the  'screen -ls' command.

  951.pts-0.example  (03/08/2023 08:16:30 AM)        (Detached)
        901.pts-0.example  (03/08/2023 08:09:41 AM)        (Detached)
        890.pts-0.example  (03/08/2023 08:08:54 AM)        (Detached)
        885.pts-0.example  (03/08/2023 08:08:07 AM)        (Detached)

Detach from a session

Ctrl+a d - Detaches from the current Screen session.

You can also detach a running session via the following command:

screen -d <name>

The Ctrl+a D D command lets you detach and logout directly.

Create a new window

Ctrl+a c - Create a new window.

Switch  window

Ctrl+a num - Specify the window number and switch to it (example 2).

Ctrl+a session_name - Specify the window name and switch to it (example session-2).

Ctrl+a n  or Ctrl+a <space>- Switches to the next window.

Ctrl+a p  or Ctrl+a <backspace>- Switches to the previous window.

Ctrl+a <Tab> - Displays a list of all the available windows and lets you select one by using the arrow keys.

Ctrl+a A - Rename the current window

Terminate window

Ctrl-a K- Kill the current window

Ctrl-a \ - Kill all windows

Split regions

Ctrl+a S - Split the currently active region horizontally into two.

Ctrl+a | - Split the currently active region vertically into two.

Ctrl+a tab - Switch the input focus to the next region.

Ctrl+a Ctrl+a - Toggle between windows.

Ctrl+a Q - Close all regions except the currently active one.

Ctrl+a X - Close the currently active region.

Return to screen command prompt

Ctrl+a : - Enters the Screen command prompt, where you can execute various commands. For example, quit to exit Screen, help to show the help screen, resize to resize the current window.

Other usable commands

ctrl+a x - Lets you lock the current session and protect it with a password.

ctrl+a H - Enables logging in to the screen session.

ctrl+a [ -Enter copy mode.

ctrl+a ] - Paste.

Customization

Screen comes with a lot of useful features that can make your work with the terminal more efficient. However,  Screen is also highly customizable, allowing you to modify its behavior and appearance as per your preference.

You can modify the default settings for Screen  through a personalized .screenrc file which contains commands to be executed at startup or using the colon command.

Screen reads its configuration parameters from /etc/screenrc and ~/.screenrc.

Commands are listed one per line and empty lines are ignored. A command’s arguments are separated by tabs or spaces and may be surrounded by single or double quotes. A ‘#’ turns the rest of the line into a comment, except in quotes. Commands may contain references to environment variables.

Your screen distribution comes with two configuration files: etc/screenrc and etc/etcscreenrc. They contain a number of useful examples for various commands.