utilities flush the file system cache to disk, send all running processes a
(and subsequently a
) and, respectively, halt or restart the system. The action is logged, including entering a shutdown record into the user accounting database.
The options are as follows:
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
Boot the specified
kernel on the next system boot. If the kernel boots successfully, the
default kernel will be booted on successive 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.
The halt or reboot is
not logged to the system log. This option is intended for applications such as
shutdown(8), that call
halt and log this themselves.
The file system cache is not flushed. This option should probably not be used.
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
reboot was called.
The system is halted or restarted quickly and ungracefully, and only the flushing of the file system cache is performed (if the
-n option is not specified). This option should probably not be used.
The fasthalt and fastboot utilities are nothing more than aliases for the halt and reboot utilities.
Normally, the shutdown(8) utility is used when the system needs to be halted or restarted, giving users advance warning of their impending doom and cleanly terminating specific programs.