Turning on/off the logfile

PostgreSQL spits out logging information to stdout and stderr which can 
then be piped to a file to act as a "log file". Is there a way to get 
PostgreSQL to enable/disable this output without restarting the server? 
Currently I have to edit /etc/rc.d/init.d/postgresql to run postgresql 
with >mylogfile or >/dev/null, and restart the server.

If there isn't an ability to do this, I think I'll whip up a little script 
that will read stderr/stdin but listen to signals and turn the output on or 
off.

Thanks.

Gerald.