Linux Screen Tutorial

Screen is a shell layer that allows you to use one shell session, detach from it, and then reattach from a different computer where you left off. It’s useful for long jobs, recording what commands were run, and bad connections that might drop your SSH shell in the middle of a work session.

Install Screen

For Debian-Based Linux, the command is:

Start Screen

Start screen with the simple “screen” command and hit enter to begin using it.

Screen Commands

Here is the TLDR version that you probably are looking for:

• screen -S something
• screen -ls
• screen -r xxxx.something -D

Everything Else besides TLDR:

Linux Screen uses ctrl + a to start commands and then a character to do a specific command. You can see all of the commands using ctrl-a ?

Ctrl-a ?	Show Help File
Ctrl-a H	Create or Stop Log of Session

A pwd will tell you what your working directory is, and you will have a screenlog.0 file in it with whatever commands you typed. If you Ctrl-a H again it will stop logging.

Ctrl-a M	Monitor for output
Ctrl-a _	Monitor for silence
Ctrl-a x	Lock Screen
Ctrl-a d	Detach Screen
Ctrl-a c	Create new screen
screen -ls	List all Screens

screen -r xxxx

Reattach to existing Screen xxxx

Ctrl-a n	Cycle to Next Screen
Ctrl-a p	Cycle to Previous Screen
Ctrl-a k	Stop Screen

When you finally type “exit” or ctrl-a k to kill a session you will see the [screen is terminating] message.

Check if Screen is Running

If screen isn’t running, you can verify using the pgrep utilitiy

If screen is running, you will get 2 process IDs:

Example of Using Screen

screen	Start screen
ctrl a, H	Turn on logging
ctrl a, c	Make a New Screen
start some command	long boring output
ctrl a, c	Makes a new screen
do other commands	bleh bleh whatever
ctrl a, n	Cycle to the next screen
exit	Type exit, it will scroll through screens shutting them down each time.

Now you can review screenlog.0 file