Envrironment and Files section, explained exactly what -w
does)

This is a patch which allows pg_ctl to make an intelligent
guess as to the proper port when running 'psql -l' to
determine if the database has started up (the -w flag).

The environment variable PGPORT is used. If that is not found,
it checks if a specific port has been set inside the postgresql.conf
file. If it is has not, it uses the port that Postgres was
compiled with.

Greg Sabino Mullane  greg@turnstep.com