Linux Screen

Getting Started with Linux Screen

Long-running tasks such as database migrations, backups, software updates, or large file transfers can be frustrating if your SSH connection drops or your terminal closes unexpectedly. GNU Screen solves this problem by allowing you to create persistent terminal sessions that continue running even after you disconnect.

With Screen, you can detach from a session, reconnect later, and continue exactly where you left off. It also allows you to manage multiple terminal windows within a single session, making it a valuable tool for Linux system administration.

Installing Screen

Ubuntu / Debian

sudo apt install screen

RHEL / Rocky Linux

sudo yum install screen

After installation, verify that Screen is available by checking its version:

screen --version

Starting a Screen Session

Launch Screen by running:

screen

The first time Screen starts, you’ll be presented with the GNU license agreement. Press Space to continue, and you’ll be dropped into what appears to be a normal terminal session.

Although it looks like a regular shell, you’re now working inside a Screen session.

Creating Named Sessions

By default, Screen assigns a session name based on its process ID (PID). While this works, it quickly becomes difficult to manage multiple sessions.

Naming your sessions makes it much easier to identify their purpose.

For example, if you’re performing a database migration:

screen -S example_db_migration

Using descriptive names makes it easier for you—or another administrator—to identify the correct session later.

Viewing Existing Sessions

To list all running Screen sessions, use:

screen -ls

The output includes:

• Session ID (PID)
• Session name
• Creation date
• Whether the session is attached or detached

Example

There is a screen on:
14460.example_db_migration (Detached)
2 Sockets in /run/screen/S-aaronk

Reattaching to a Session

If you’ve detached from a session, reconnect using either the session name or PID:

screen -r <SESSION_NAME_OR_PID>

Example:

screen -r example_db_migration

or

screen -r 12345

To verify you’re inside the expected Screen session, run:

echo $STY

This returns the session’s PID and name.

Detaching from a Session

One of Screen’s most useful features is the ability to leave a session running while disconnecting from it.

Press:

[ctrl + a] d

Your programs continue running in the background, allowing you to safely close your terminal or SSH session.

Now you should be attached to the existing screen session. To confirm run echo $STY and that will give you the PID and name of the existing session.

Closing a Screen Session

Closing a Screen Session

When you’re finished with a session, you can terminate it by pressing:

Ctrl + A, then K

Screen will ask for confirmation:

Really kill this window [y/n]

Press Y to close the session.

Alternatively, if you’ve finished the work running inside Screen, simply type:

exit

This will also end the session when no shells or processes remain.

Common Keyboard Shortcuts

Function	Shortcut
Detach from session	[ctrl + a] d
Split screen vertically	[ctrl + a] |
Split screen horizontally	[ctrl + a] Shift + S
Move between screens	[ctrl + a] Tab
Rename current window	[ctrl + a] Shift + A
Kill current window	[ctrl + a] k
Show all commands	[ctrl + a] ?

Why Use Screen?

GNU Screen is a lightweight yet powerful utility that every Linux administrator should know. Whether you’re managing servers remotely or running commands that may take hours to complete, Screen ensures your work continues even if your connection doesn’t.

A few common use cases include:

• Database migrations
• Software updates
• Large file transfers
• Log monitoring
• Backup and restore operations
• Long-running scripts or automation

Once you begin using Screen regularly, it quickly becomes an essential part of your Linux administration toolkit.