If one isn't specified as an optional parameter, Pidpau uses startstop's configuration file, startstop*.d to enable it to attach to the shared memory regions.
Pidpau needs the process id (PID) of the module it's attempting to stop. You can find out the process id by getting the status from typing Enter in an interactive startstop session, or by running the 'status' command, or by looking at UNIX's process list (with ps) or by looking at Windows Task Manager with display of Process ID activated.
Usage: pidpau <process_id> <optional:startstop config file>