Let's say you keep five SSH windows open because each one is one thing, and your window manager has opinions.

tmux enables a number of terminals to be created, accessed and controlled from a single screen, says the manual. Many terminals, one window, each doing its job. The bar along the bottom is the status line, and it's how you know where you are.

One screen. As many terminals as you want.

Let's say someone says just attach to the session and you nod, having no picture behind the word.

Here's the picture. A session is a collection of pseudo terminals; each session has one or more windows; a window fills the screen and may be split into panes, each pane its own terminal. Session, windows, panes. Three levels, that's the whole tree.

Session holds windows. Windows split into panes.

Let's say the train goes through a tunnel and the deploy dies with the SSH line. Again.

Each session is persistent and will survive accidental disconnection or intentional detaching with C-b d, says the manual. The session runs inside tmux on the server, not inside your connection. Reconnect, tmux attach, and it's all still there.

The session never lived in your connection.

Let's say you close the laptop and the session survives, and nobody ever told you what was holding it.

All sessions are managed by a single server; clients and the server are separate processes talking through a socket in /tmp, says the manual. Your terminal is just a client, a window onto the server's sessions. Expecting the last window closed to stop the server is the leftover; sessions, not windows, are what keep it alive.

Clients come and go. The server stays.

Let's say you press C-b and nothing happens, and you conclude tmux is broken. It's listening.

tmux is controlled by a prefix key, C-b by default, followed by a command key, says the manual. It's a knock, then a request. C-b then c makes a window, C-b then d detaches. Holding C-b down like a modifier is the classic fumble; press, release, then the command key.

Knock first. Then ask.

Let's say your morning routine is tmux ls, squint, then either new or attach. There's a flag for that.

-A makes new-session behave like attach-session if the name already exists, says the manual. tmux new -A -s work makes it if it's missing, attaches if it's not. Same keystrokes every morning, no squinting.

One command. Both cases. Habit formed.

Let's say you got this far and the prefix still feels like a stranger sometimes.

It's a tree, and now you know it: a server holds sessions, sessions hold windows, windows split into panes, and each node carries an ID for life, says the manual. C-b w shows it, one command a day walks it. The spaced-practice line applies here too: a rep a day beats a binge a month.

Server, sessions, windows, panes. Say it until it's boring.