Screen on Linux: Keep Commands Running After SSH Disconnects

If an SSH connection drops during a long operation — a system upgrade, a backup, a project build — the process dies with the session. The screen utility solves this: the program keeps running on the server, and you can disconnect and come back to it later.

Installation

Ubuntu and Debian:

sudo apt install screen

AlmaLinux, Rocky Linux (the package is in the EPEL repository):

sudo dnf install epel-release
sudo dnf install screen

The basic workflow

Create a session with a meaningful name:

screen -S backup

A new shell opens. Start your command in it, then detach from the session with Ctrl+A, then D. The program keeps running and you can close the SSH connection.

Later, connect to the server and return to the session:

screen -r backup

Managing sessions

screen -ls              # list sessions
screen -r backup        # reattach to a session
screen -d -r backup     # reattach even if the session is open elsewhere
screen -S backup -X quit   # terminate a session

A session also ends when you leave its shell with exit.

Start a command straight in the background

To run a program in its own session without opening it:

screen -dmS backup /opt/scripts/backup.sh

The session closes automatically when the command finishes.

Key bindings

Every binding starts with Ctrl+A, followed by a second key.

Keys	Action
Ctrl+A, D	detach from the session
Ctrl+A, C	create a new window
Ctrl+A, N / P	next / previous window
Ctrl+A, "	list windows
Ctrl+A, A	rename the window
Ctrl+A, S	split the screen horizontally
Ctrl+A, Tab	move to the next region
Ctrl+A, [	scrollback mode (leave with Esc)
Ctrl+A, K	close the current window
Ctrl+A, ?	key binding help

Logging output to a file

The -L option saves everything printed in the session to screenlog.0 in the current directory:

screen -L -S deploy

That is handy for reading messages that have scrolled off the screen after a long operation.

Useful settings

Create ~/.screenrc:

defscrollback 10000
startup_message off
hardstatus alwayslastline "%H | %w"

The first line enlarges the scrollback buffer, the second removes the start-up message, and the third shows the host name and window list at the bottom.

Frequently asked questions

The session is marked Attached and I cannot return to it. The connection dropped, but the session thinks you are still attached. Use screen -d -r name.

Is there an alternative? Yes, tmux — a more modern equivalent with convenient screen splitting. screen is simpler and more often already installed on a server, so it is enough for “start and disconnect”.

What if the process must run permanently? For long-running services use systemd or containers, and for scheduled jobs use cron. screen is meant for one-off long operations on a server.