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TMUX · BASIC STRUCTURE
NOTES — ED. 2026.08

Keep multiple tasks in one terminal.
Leave the screen; keep the processes running.

Technical Reference · Drafted with Codex.

tmux is a terminal multiplexer. Start by distinguishing Session, Window, Pane and Client, then learn why the default prefix comes before each shortcut.

Notes
FIG. 01SERVER, SESSION, WINDOW, PANE — ONE TERMINAL, MANY TASKS
TMUXONE CLIENT, MANY TERMINALS

tmux — splitting terminals and reconnecting to them

MULTIPLEXING · 2026

tmux is a terminal multiplexer that lets you run several terminal programs inside one terminal. Place different programs—shells, editors, servers and AI coding tools—in separate Windows and Panes, and switch between them on one screen.

Even if you close the outer terminal or lose a remote connection, processes inside tmux can keep running while the tmux server remains alive. It is not permanent storage that survives a computer restart, termination of the tmux server or the closing of every Session. Each program, rather than tmux, also determines whether conversation history is saved.

SERVER · CLIENTSESSION · WINDOW · PANE

From Server to Pane — distinguish the four layers

THE FOUR LAYERS · 2026

The tmux server manages Sessions and the state of the programs inside them in the background. A Client is the connection from an outer terminal that attaches a particular Session to the screen. A Session contains several Windows, and a Window contains one or more Panes.

A Window is similar to a browser tab. The current Window fills the screen, and you switch Windows by number or name. A Pane is a rectangular subdivision of that Window. Keyboard input goes to the single active Pane in the current Window.

A glossary of tmux structure
Server
Function
The background process managing all Sessions and their running state
Analogy
A building management office
Client
Function
The display and input attached to a Session from an outer terminal
Analogy
A building entrance
Session
Function
A unit of work grouping several Windows
Analogy
A workbench for one project
Window
Function
A screen containing one or more Panes, selected by number or name
Analogy
A browser tab
Pane
Function
A rectangular area displaying one actual terminal program
Analogy
One section of a split screen
DEFAULT PREFIX · C-bPRESS, RELEASE, THEN KEY

Prefix — press Ctrl-b, then the command key

PREFIX · 2026

The default prefix is C-b: hold Ctrl and press b. Most tmux shortcuts have two stages: press C-b, release it, then press the next key. For C-b c, you do not press Ctrl-b and c together; send the prefix first, then press c.

The prefix tells tmux to receive the next key instead of passing it to the shell or running program. All shortcuts in this article use the defaults. If you changed the prefix or key bindings in your configuration file, your actual settings take precedence. C-b ? opens the current list of keys.

— FIN —