Plumber is typically started by wm(1)'s startup script. It reads each rulefile (default: /usr/user/lib/plumbing) in turn. Each file has the form described in plumbing(6); the rules direct the routing of each message plumber receives. Plumber then lurks in the background with its mate, awaiting plumbing requests sent by plumbmsg(2), by windowing applications in response to events such as button clicks or drag-and-drop, or by plumb(1).

When a message arrives, plumber applies the rules to decide how to route it. It forwards the message to the selected application's input port, starting it if necessary. If no rule applies (or some other error occurs), plumber returns an error to the message's sender. The -v option causes plumber to log the contents of messages it receives, to help debug plumbing rules and applications.

Plumber normally starts applications directly. For use on devices that have specialised window managers, not wm(1), the -w option causes plumber to start applications indirectly, by sending a message to a window manager listening on /chan/wm, allowing the window manager to track every application started. The -c option can select an alternative wmchan to /chan/wm.

/usr/user/lib/plumbing

default plumbing rules for user