Overriding defaults for postgresql

[Colin Paul Adams]

What is the recommended way of overriding default options fro
postgresql?
I want to enable the use of tcp connections, and also to change the
default port.

I see there is an empty directory, /etc/sysconfig/pgsql. I think I
have to place a file in there, but I am not sure what it should be
called, or the format of it's contents.

Thanks for any help you might be able to offer.
-- 
Colin Paul Adams
Preston Lancashire