Gracefully restarts the Apache httpd daemon. If the

daemon is not running, it is started. This differs from a

normal restart in that currently open connections are

not aborted. A side effect is that old log files will not

be closed immediately. This means that if used in a log

rotation script, a substantial delay may be necessary to

ensure that the old log files are closed before

processing them. This command automatically checks

the configuration files as in configtest before

initiating the restart to make sure Apache doesn?t die.

This is equivalent to apachectl -k graceful.

( excerpt from manual page of apachectl )

Actually it sends a SIGUSR1 for a restart. The USR1 or

graceful signal causes the parent process to advise the

children to exit after their current request (or to exit

immediately if they're not serving anything). The parent

re-reads its configuration files and re-opens its log files.

As each child dies off the parent replaces it with a child

from the new generation of the configuration, which begins

serving new requests immediately.