GNU screen was released in 1987 and was the standard terminal multiplexer for two decades. Most new work today uses tmux instead — better defaults, cleaner config, more active development — but screen is still everywhere. It's pre-installed on most older Linux distributions, on locked-down systems where you can't add packages, and on legacy servers that have been running undisturbed for years.
The concepts are identical to tmux: sessions you can detach from and reattach to, multiple windows, the ability to split. Only the keystrokes differ.
When you'll encounter it
- Old RHEL / CentOS servers where screen ships in the base install and tmux isn't.
- Locked-down systems (regulated environments, hardened images) where you can't install new packages.
- The pre-existing screen session the previous admin started before they left. (Yes, this happens.)
- Embedded systems — routers, switches, IoT devices — that ship with a stripped-down toolset.
The first five minutes
The prefix key
Screen's prefix is Ctrl+a (rather than tmux's Ctrl+b). Press Ctrl+a, release, then press the command key. People who use both tools usually remap tmux's prefix to Ctrl+a to match screen.
Cheat sheet
| screen | tmux equivalent | What it does |
|---|---|---|
| Ctrl+a d | Ctrl+b d | Detach (session keeps running) |
| Ctrl+a c | Ctrl+b c | Create a new window |
| Ctrl+a n | Ctrl+b n | Next window |
| Ctrl+a p | Ctrl+b p | Previous window |
| Ctrl+a 0..9 | Ctrl+b 0..9 | Jump to window 0..9 |
| Ctrl+a A | Ctrl+b , | Rename current window |
| Ctrl+a " | Ctrl+b w | Interactive window picker |
| Ctrl+a S | Ctrl+b " | Split horizontally |
| Ctrl+a | | Ctrl+b % | Split vertically |
| Ctrl+a Tab | Ctrl+b arrow | Move to next pane region |
| Ctrl+a X | Ctrl+b x | Close current region |
| Ctrl+a [ | Ctrl+b [ | Enter copy/scroll mode |
| Ctrl+a ? | Ctrl+b ? | Show all key bindings |
| Ctrl+a k | Ctrl+b & | Kill current window (asks first) |
Ctrl+a c (or attach a window to it with Ctrl+a "). In tmux, splitting creates a pane that immediately spawns a shell. Screen's split workflow is fussier; one of the reasons most people prefer tmux.Saving the scrollback to a file
screen's copy mode (Ctrl+a [) can scroll back through buffered output. To dump it to a file, drop this in your ~/.screenrc and use the hardcopy command:
When to switch to tmux
If you have a choice between the two on a new system, use tmux. Reasons:
- Active development. tmux gets new features and bug fixes; screen has been in maintenance mode for years.
- Cleaner config. tmux's
.tmux.confis far more readable than screen's.screenrc. - Better default split workflow. tmux splits and runs shells in one motion; screen requires a follow-up step.
- Mouse support is real. Modern tmux handles clicks, scrolls, and drags out of the box. Screen requires invocations.
Reasons to know screen anyway: it might be all you have. When you SSH into a box that's eight years old and you need a persistent session before kicking off a long task, screen is on the box and tmux isn't. Knowing the 12 keystrokes above is enough for that.
Screen and tmux solve the same problem with different keystrokes. Learn one well; learn the other's prefix and split commands so you can survive on a system where you don't get a choice.
For your day-to-day work, default to tmux. For the legacy server you SSH into once a year, screen is right there waiting — and the cheat sheet above will get you through the session.
References
Formatted in APA 7. Alphabetized by first author's last name.
- GNU Project. (n.d.). GNU screen manual. Free Software Foundation. https://www.gnu.org/software/screen/manual/screen.html
- Kerrisk, M. (n.d.). screen(1): Linux manual page. Linux man-pages project. https://man7.org/linux/man-pages/man1/screen.1.html