kill -HUP `cat /usr/local/apache2/logs/httpd.pid`
HUP Signal: restart now
Sending the HUP signal to the parent causes it to kill off its children like in TERM but the parent doesn't exit. It re-reads its configuration files, and re-opens any log files. Then it spawns a new set of children and continues serving hits.
Users of the status module will notice that the server statistics are set to zero when a HUP is sent.
Note: If your configuration file has errors in it when you issue a restart then your parent will not restart, it will exit with an error. See below for a method of avoiding this.
...taken from Stopping and Restarting Apache