The Server You Started Without Noticing

Leave a build running in tmux and walk away: tmux ls shows it is still there, and you can come back to it. While you are away, who keeps that build running?

The tmux server. Not the kind of server the word usually brings to mind. It is not a service you install or enable. It is born the moment you first type tmux, and it exits on its own once no sessions are left. That is what tmux ls means when it says no server running. It never touches the network either. The connection is one file in a directory under /tmp that only you can read.

Closing your window does not stop the work, because the work was never watching your window. It had been handed to this small server.

We call it a server, but it is not a machine far away. It stands up for you, and folds away when nobody is left.