Never Lose Your SSH Session Again: Master GNU Screen on Linux

Introduction

GNU Screen is a terminal multiplexer that lets you run multiple virtual terminals inside a single SSH session; processes continue running even if the connection drops.

Installing Screen

Most Linux distributions ship with Screen pre‑installed. Verify with: screen --version If missing, install it using your package manager:

Ubuntu/Debian: sudo apt install screen CentOS/Fedora:

sudo yum install screen

Starting a Screen Session

Launch a new session by typing: screen This creates a window with a shell. View the command list with Ctrl+a ?.

Naming Sessions

Give a session a descriptive name to manage multiple sessions:

screen -S session_name

Using Screen Windows

Screen starts with one window. Create additional windows with Ctrl+a c. Switch between windows using Ctrl+a 0 … Ctrl+a 9. Common window management shortcuts: Ctrl+a c – create new window Ctrl+a " – list all windows Ctrl+a 0 – switch to window 0 Ctrl+a A – rename current window Ctrl+a S – split region horizontally Ctrl+a | – split region vertically Ctrl+a Tab – move focus to next region Ctrl+a Q – close all regions except current Ctrl+a X – close current region

Nested Session Shortcuts

Ctrl+a "

– list all sessions Ctrl+a 0 – switch to session 0 Ctrl+a n – next session Ctrl+a p – previous session Ctrl+a \\ – terminate all sessions and Screen

Detaching and Re‑attaching

Detach from a session without stopping its processes: Ctrl+a d Later, re‑attach with: screen -r If multiple sessions exist, list them with screen -ls and re‑attach a specific one using its ID, e.g., screen -r 15105.

Customizing Screen

Screen reads configuration from /etc/screenrc and ~/.screenrc. Example .screenrc to disable the welcome message, turn off visual bell, increase scrollback, and set a custom status line:

# Disable startup message
startup_message off
# Disable visual bell
vbell off
# Set scrollback buffer size
defscrollback 10000
# Custom status line
hardstatus alwayslastline
hardstatus string '%{= kG}[ %{G}%H %{g}][%= %{= kw}%?%-Lw%?%{r}(%{W}%n*%f%t%?(%u)%?%{r})%{w}%?%+Lw%?%?%= %{g}][%{B} %m-%d %{W}%c %{g}]'

Basic Usage Steps

Start Screen: screen Run the desired program inside the window.

Detach safely with Ctrl+a Ctrl+d.

Re‑attach later using screen -r.

Conclusion

You now know how to install and use GNU Screen to create multiple windows, navigate between them, detach and resume sessions, and personalize the environment with a .screenrc file, ensuring your long‑running tasks survive SSH disconnects.