Sessions, Windows and Panes: Learning tmux With Gavos

I have made it a mission to learn tmux properly.

That probably sounds slightly ridiculous because I first wrote “tmux - where have you been all my life?” back in 2016, and I revisited the subject in my terminal multiplexing guide earlier this year. I know what tmux does. I understand why people love it. Yet when I am connected to a Linux box and need a long-running shell, my hands still type screen.

GNU Screen is my traditional go-to. It is dependable, familiar and buried deep in my muscle memory. Under pressure, familiarity wins.

So I have tried a different tactic: I have built tmux into Gavos, the secret console on gavinj.net. Press the backtick key on a desktop browser, type tmux, and Gavos now gives you sessions, windows, panes, the standard Ctrl-b prefix and a man tmux page. There are clickable tabs too, but the keyboard shortcuts are the point.

The implementation is deliberately a browser-sized teaching version, not a replacement for real tmux. Sessions persist while the page remains open, including when the console is hidden or the session is detached. The aim is to make the core model familiar enough that the real thing stops feeling foreign.

Emulator or multiplexer?

I think every Linux administrator should know how to use a terminal multiplexer.

That wording matters. iTerm2, Terminator and WezTerm are terminal emulators: they provide the window in which a shell runs. tmux and GNU Screen are terminal multiplexers: they run inside that terminal, keep multiple shells organised and let you detach a client without ending the session.

For an administrator, that last part is the killer feature. Start an upgrade, a log tail or an incident-response session inside tmux and a dropped SSH connection does not have to destroy your working context. Reconnect, reattach and carry on. The tmux server and its programs still need the host to remain running; ordinary tmux sessions do not magically survive a reboot.

Screen already solves the persistence problem. What attracts me to tmux is the way sessions, windows and panes fit together, the discoverable command interface, and how natural it feels to build a whole working layout inside one connection. It feels like the modern refinement of the workflow I already trust.

Install tmux

tmux is packaged by the major Linux distributions. The commands below follow the project's official installation guide:

# Debian or Ubuntu
sudo apt install tmux

# Fedora
sudo dnf install tmux

# RHEL or CentOS
sudo yum install tmux

# Arch Linux
sudo pacman -S tmux

# openSUSE
sudo zypper install tmux

# macOS with Homebrew
brew install tmux

Confirm what you installed with:

tmux -V

The mental model

tmux has three layers:

• A session is a persistent workspace. You might have one called production and another called blog.
• A window is a full terminal screen inside a session. Think of it as a tab.
• A pane is one split region inside a window.

Most shortcuts begin with the default prefix, Ctrl-b. Press and release Ctrl-b, then press the command key. It is a sequence, not one giant chord. In tmux notation, that prefix appears as C-b.

Your first ten minutes

Create and attach to a named session:

tmux new -s learning

Now practise this little circuit:

1. Press Ctrl-b c to create another window.
2. Press Ctrl-b % to split the current pane into left and right panes.
3. Press Ctrl-b " to split the current pane into top and bottom panes.
4. Press Ctrl-b followed by an arrow key to move between panes.
5. Press Ctrl-b z to zoom the active pane, then repeat it to restore the layout.
6. Press Ctrl-b d to detach from the session.

Back at the ordinary shell, list the sessions:

tmux ls

Then return to the one you created:

tmux attach -t learning

That is the essential tmux loop: create, organise, detach, reattach. The official Getting Started guide goes deeper, but this is enough to make tmux useful today.

Where iTerm2 Has the Edge

iTerm2 on macOS has a genuinely clever tmux integration. Run tmux -CC new -s admin, or reattach with tmux -CC attach -t admin, and iTerm2 uses tmux's control mode to present tmux windows and panes as native iTerm2 tabs and split panes. Creating, closing and resizing them in the GUI sends the corresponding commands to tmux. If SSH drops, tmux keeps the session running; reconnecting and attaching can restore those iTerm2 windows.

That is different from merely running tmux inside a split terminal. tmux control mode is a text protocol designed so applications can drive tmux and render its panes in their own interface.

I wish Terminator did the same thing. Terminator is still my familiar Linux terminal and it already has very good native tabs and split panes: Ctrl-Shift-O splits horizontally and Ctrl-Shift-E splits vertically. What I could not find in its current documentation is an iTerm2-style tmux control-mode integration. Terminator's splits and tmux's panes therefore remain two separate layers rather than one shared layout.

The closest well-documented Linux equivalent I found is WezTerm's built-in multiplexing. WezTerm can attach local or remote multiplexing domains to its native windows, tabs and panes, giving a very similar user experience on Linux. There is an important catch: it uses the WezTerm multiplexer, not tmux control mode, and a compatible WezTerm installation is required on the remote host for its SSH multiplexing domains. It is an alternative to the workflow, not a drop-in GUI for an existing tmux session.

Essential tmux cheat sheet

Everything in the second table follows Ctrl-b. For example, “c” means press and release Ctrl-b, then press c. These are the default bindings documented in the tmux manual.

From the shell

Inside tmux

If you remember only six combinations, make them c, %, ", an arrow key, z and d. You can always use Ctrl-b ? when your memory fails.

Building the habit

My plan is intentionally boring:

• Start a named tmux session whenever I SSH into a machine to do real work.
• Use windows for separate jobs and panes when I need to see two jobs at once.
• Detach before disconnecting, even when I do not strictly need to.
• Keep the default Ctrl-b prefix until the standard shortcuts become automatic.
• Practise in Gavos when I catch myself reaching for Screen.

I am not deleting screen or pretending it suddenly became a bad tool. This is about replacing a reflex, and reflexes only change through repetition. I can already see why tmux is better for the way I want to work. Now I need my fingers to catch up.

Press the backtick key anywhere on gavinj.net, type tmux, and have a play. If you get lost, Ctrl-b ? and man tmux are there to bring you home.

Further reading:

• tmux: where have you been all my life?
• From Screen to Supreme: The Evolution of Terminal Multiplexing
• Official tmux Getting Started guide
• Official tmux manual