screen command in linux

1. Installing Linux Screen Command

The screen comes preinstalled on some of the popular distributions. You can check if it is installed on your server using the following command

screen -v

Screen Command Example in Linux

If you do not have a screen to the VPS, you can easily install it using the package manager provided by the OS.

 2. Install Linux Screen Command – CentOS/RedHat/Fedora

yum -y install screen

Ubuntu/Debian

apt-get -y install screen

3. How to start a Linux Screen Command session

You can start screen by typing ‘screen’ at the command prompt and a new screen session will be started which looks the same as the command prompt

screen

It is a good practice to start screen sessions with descriptive names so you can easily remember which process is running in the session. To create a new session with a session name run the following command

screen -S name

and replace ‘name’ with a meaningful name for your session.

4. Detach from Linux Screen Command Session

To detach from the current screen session you can press ‘Ctrl-A‘ and ‘d‘ on your keyboard. All screen sessions will still be active and you can re-attach to them at any time later.

5. Reattach to Linux Screen Command

If you have detached from a session or your connection is interrupted for some reason, you can easily re-attach by executing the following command:

screen -r

If you have multiple screen sessions you can list them with ‘ls’

screen -ls

There are screens on:

7880.session    (Detached)

7934.session2   (Detached)

7907.session1   (Detached)

3 Sockets in /var/run/screen/S-root.

linux screen command list

linux screen command list

In our example, we have three active screen sessions. So, if you want to restore the session ‘session2’ you can execute

screen -r 7934

or you can use the screen name

screen -r -S session2

6. Terminate Linux Screen Command Session

There are several ways to terminate the screen session. You can do it by pressing ‘Ctrl‘ + ‘d‘ on your keyboard or use the ‘exit’ command-line command.

To see all the useful features of the screen command you can check the screen’s man page.

man screen

NAME

screen - screen manager with VT100/ANSI terminal emulation

SYNOPSIS

screen [ -options ] [ cmd [ args ] ]

screen -r [[pid.]tty[.host]]

screen -r sessionowner/[[pid.]tty[.host]]

How to access attached screen after connection dropped

Here’s the situation, you are using bash’s Screen command because you don’t want your flakey internet connection to affect whatever you are working on, and sure enough, the connection drops. Sometimes, when you try to re-attach to this screen session you are told that the screen session is still attached…

~$ screen -r '1234.somescreensession'
There is a screen on:
1234.somescreensession (Attached)
There is no screen to be resumed matching 1234.somescreensession.

How annoying.

UPDATE:
Here is a simple way to take back that screen session.

screen -D -r '1234.somescreensession'

Kudos to Donncha O’Caoimh

Here is a way a longer way to remove the process that is attached to that screen session, so you can reattach to it and continue with whatever you were doing.

• figure out which tty is holding on to the screen session by typing into terminal
  ps -ef | grep screen
• result of this should be something like
  testdev 5760 5688 0 12:31 ttyp1 00:00:00 screen -r 1234.somescreensession
• in this case the tty is 5688, use this to find the login bash that is associated with that tty
  ps -ef | grep bash | grep 5688
• result of this should be something like
  testdev 5688 5687 0 12:28 ttyp1 00:00:00 -bash
• kill process
  kill -9 5687

Now you should be free to re-attach to this screen session.