Читаем man halt И видим Код: router# man halt REBOOT(8) FreeBSD System Manager's Manual REBOOT(8) NAME reboot, halt, fastboot, fasthalt -- stopping and restarting the system SYNOPSIS halt [-lnpq] [-k kernel] reboot [-dlnpq] [-k kernel] fasthalt [-lnpq] [-k kernel] fastboot [-dlnpq] [-k kernel] DESCRIPTION The halt and reboot utilities flush the file system cache to disk, send all running processes a SIGTERM (and subsequently a SIGKILL) and, respec- tively, halt or restart the system. The action is logged, including entering a shutdown record into the wtmp(5) file. The options are as follows: -d The system is requested to create a crash dump. This option is supported only when rebooting, and it has no effect unless a dump device has previously been specified with dumpon(8). -k kernel Boot the specified kernel on the next system boot. If the kernel boots successfully, the default kernel will be booted on succes- sive boots, this is a one-shot option. If the boot fails, the system will continue attempting to boot kernel until the boot process is interrupted and a valid kernel booted. This may change in the future. -l The halt or reboot is not logged to the system log. This option is intended for applications such as shutdown(8), that call reboot or halt and log this themselves. -n The file system cache is not flushed. This option should proba- bly not be used. [B]-p The system will turn off the power if it can. If the power down action fails, the system will halt or reboot normally, depending on whether halt or reboot was called.[/B] -q The system is halted or restarted quickly and ungracefully, and соответственно набираете команду halt -p now
