What Is tmux?
A terminal multiplexer — one screen, many sessions
tmux gives one terminal window many independent sessions, windows, and panes. Detach without losing state. Reattach from anywhere. The standard partner program for Vim.
tmux — short for terminal multiplexer — turns one terminal window into many. A single tmux session can hold any number of windows; each window can be split into any number of panes; panes run independent shells. You attach to a session, do your work, detach, and the session keeps running in the background. Reattach hours or days later from a completely different terminal — sometimes from a completely different computer over SSH — and pick up exactly where you left off.
Start it by typing tmux at any shell. You'll see your shell again, this time with a green status bar across the bottom. Everything you do from now on is happening inside the tmux session. The status bar is the only obvious sign tmux is there.
| Concept | What it is | Mental model |
|---|---|---|
| Pane | A single shell, drawn inside a rectangle on your screen | A window into a process |
| Window | A full-screen layout containing one or more panes | Like a virtual desktop, scoped to a session |
| Session | A named collection of windows that can be detached and reattached | A workspace that survives terminal closes and SSH disconnects |
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See also: The Prefix Key, Panes — Split, Navigate, Resize