Upon controlled shutdown, via shutdown(8), init(8) will attempt to run the script /etc/rc.shutdown, and then proceed to send all processes the TERM signal, and subsequently the KILL signal to any that do not terminate timely.
To power down a FreeBSD machine on architectures and systems that support power management, use the command shutdown -p now to turn the power off immediately. To just reboot a FreeBSD system, just use shutdown -r now. You need to be root or a member of operator group to run shutdown(8). The halt(8) and reboot(8) commands can also be used, please refer to their manual pages and to shutdown(8)'s one for more information.
Note: Power management requires acpi(4) support in the kernel or loaded as module for.