What is the Linux Screen Command and How to use it?

The Linux Screen utility is a powerful tool that allows users to create multiple virtual terminal sessions within a single terminal window or SSH session. It enables you to detach and reattach terminal sessions, which is particularly useful when working on remote servers or long-running processes that you don’t want to be interrupted if your connection drops.

Here’s a detailed explanation of how to use the Linux Screen utility:

Installation:

If Screen is not already installed on your system, you can install it using your distribution’s package manager. For example, on Debian-based systems like Ubuntu, you can install it with the following command:

Basic Usage:

1. Starting a Screen Session: To start a new Screen session, simply type:
   screen


   This will create a new session with a single terminal window.

2. Working within Screen: Inside a Screen session, you can work as you would in a regular terminal window. You can run commands, edit files, and perform any other tasks.
3. Detaching from a Session: To detach from the current Screen session without terminating it, press Ctrl + A followed by Ctrl + D. This will return you to the shell prompt while leaving the Screen session running in the background.
4. Listing Screen Sessions: You can list all active Screen sessions by typing:
   screen -ls


   This will display the list of active Screen sessions along with their session IDs.

5. Reattaching to a Session: To reattach to a detached Screen session, use the following command:
   screen -r [session_id]

   Replace [session_id] with the ID of the Screen session you want to reattach to. If there is only one detached session, you can omit the session ID.

6. Creating Named Sessions: You can create named Screen sessions for easier identification and management. To start a named session, use the -S option followed by the session name:
   screen -S [session_name]
7. Exiting a Screen Session: To exit a Screen session, simply type exit within the session and press Enter. This will terminate the Screen session and return you to the shell prompt.

Advanced Usage:

8. Splitting the Screen: Screen allows you to split the terminal window into multiple regions, each displaying a different terminal session. Press Ctrl + A followed by S to split the current region horizontally, or Ctrl + A followed by | to split it vertically.
9. Navigating between Regions: You can navigate between different regions within a Screen session using Ctrl + A followed by Tab.
10. Copying and Scrolling: Screen allows you to copy and scroll within the terminal window. Press Ctrl + A followed by [ to enter copy mode. Use the arrow keys or page up/page down keys to navigate, and Space to start selecting text. Press Enter to copy the selected text. To exit copy mode, press Esc.
11. Configuration File: Screen settings can be customized using a configuration file located at ~/.screenrc. You can define default settings, key bindings, and other preferences in this file.

Linux Screen is a versatile utility that enhances terminal multiplexing and remote access capabilities, making it an essential tool for system administrators, developers, and anyone who frequently works in the command line environment.