Tutorial | How to Use Linux Screen

By /

Why Screen?

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 distributions nowadays.
You can check if it is installed on your system by typing: screen --version.

If you don’t have screen installed, you can easily install it using the package manager by:
sudo apt update && sudo apt install screen

Start a Screen Session

To start a screen session, simply type screen in your console.
To start a named session, use 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 windows.
  • 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 windows
  • Ctrl+a Q Close all regions but the current one.
  • Ctrl+a X Close the current region.

Detach/Reattach 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.
To resume your screen session, use screen -r
To find the session ID list the current running screen sessions with, use screen -ls
To resume your screen session with ID, use screen -r [session ID]

Options and Shortcut Keys

Options
  • -a: It force all capabilities into each window’s termcap.
  • -A -[r|R]: It adapt all windows to the new display width & height.
  • -c file: It read configuration file instead of ‘.screenrc’.
  • -d (-r): It detach the elsewhere running screen (and reattach here).
  • -dmS name: It start as daemon: Screen session in detached mode.
  • -D (-r): It detach and logout remote (and reattach here).
  • -D -RR: It do whatever is needed to get a screen session.
  • -e xy: It change the command characters.
  • -f: It make the flow control on, -fn = off, -fa = auto.
  • -h lines: It set the size of the scrollback history buffer.
  • -i: It interrupt output sooner when flow control is on.
  • -l: It make the login mode on (update /var/run/utmp), -ln = off.
  • -ls [match]: It display all the attached screens.
  • -L: It turn on output logging.
  • -m: It ignore $STY variable, do create a new screen session.
  • -O: It choose optimal output rather than exact vt100 emulation.
  • -p window: It preselect the named window if it exists.
  • -q: It quiet startup. Exits with non-zero return code if unsuccessful.
  • -Q: It commands will send the response to the stdout of the querying process.
  • -r [session]: It reattach to a detached screen process.
  • -R: It reattach if possible, otherwise start a new session.
  • -S sockname: It name this session .sockname instead of …
  • -t title: It set title. (window’s name).
  • -T term: It use term as $TERM for windows, rather than “screen”.
  • -U: It tell screen to use UTF-8 encoding.
  • -v: It print “Screen version 4.06.02 (GNU) 23-Oct-17”.
  • -x: It attach to a not detached screen. (Multi display mode).
  • -X: It execute as a screen command in the specified session.
Shortcuts Keys
  • Ctrl-a + c: It create a new windows.
  • Ctrl-a + w: It display the list of all the windows currently opened.
  • Ctrl-a + A: It rename the current windows. The name will appear when you will list the list of windows opened with Ctrl-a + w.
  • Ctrl-a + n: It go to the next windows.
  • Ctrl-a + p: It go to the previous windows.
  • Ctrl-a + Ctrl-a: It back to the last windows used.
  • Ctrl-a + k: It close the current windows (kill).
  • Ctrl-a + S: It split the current windows horizontally. To switch between the windows, do Ctrl-a + Tab.
  • Ctrl-a + |: It split the current windows vertically.
  • Ctrl-a + X: Close active Split window
  • Ctrl-a + Q: Close all Split windows
  • Ctrl-a + d: It detach a screen session without stopping it.
  • Ctrl-a + r: It reattach a detached screen session.
  • Ctrl-a + [: It start the copy mode.
  • Ctrl-a + ]: It paste the copied text.
Back to Table of Content
Scroll to Top