Kill and reload Apache, which then rereads all its Config files and restarts:

% kill PID
% httpd [flags]

The same effect is achieved with less typing by using the flag -HUP to kill Apache:

% kill -HUP PID

A graceful restart is achieved with the flag -USR1. This rereads the Config files but lets the child processes run to completion, finishing any client transactions in progress, before they are replaced with updated children. In most cases, this is the best way to proceed, because it won't interrupt people who are browsing at the time (unless you messed up the Config files):

% kill -USR1 PID

A script to do the job automatically (assuming you are in the server root directory when you run it) is as follows:

#!/bin/sh
kill -USR1 `cat logs/httpd.pid`