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REBOOT(8) FreeBSD System Manager's Manual REBOOT(8)
NAME
reboot, halt, fastboot, fasthalt - stopping and restarting the system
SYNOPSIS
halt [-lNnpq] [-k kernel]
reboot [-cdlNnpqr] [-k kernel]
fasthalt [-lNnpq] [-k kernel]
fastboot [-dlNnpq] [-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,
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:
-c The system will turn off the power and then turn it back on if it
can. If the power down action fails, the system will halt or
reboot normally, depending on whether halt or reboot was called.
At the present time, only the ipmi(4) driver implements the power
cycle functionality and only on hardware with a BMC that supports
power cycling. Unlike power off, the amount of hardware that
supports power cycling is small.
-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
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.
-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 during the initial process
clean-up, however the kernel level reboot(2) is still processed
with a sync. This option can be useful for performing a
"best-effort" reboot when devices might be unavailable. This can
happen when devices have been disconnected, such as with
iscsi(4).
-n The file system cache is not flushed. This option should
probably not be used.
-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.
-q The system is halted or restarted quickly and ungracefully, and
only the flushing of the file system cache is performed (if the
This requires the tmpfs(5) kernel module to be loaded because
init(8) needs a place to store itself after the old root is
unmounted, but before the new root is in place.
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.
EXAMPLES
Replace current root filesystem with UFS mounted from /dev/ada0s1a:
kenv vfs.root.mountfrom=ufs:/dev/ada0s1a
reboot -r
This mechanism can also be used with NFS, with a caveat that it only
works with NFSv4, and requires a numeric IPv4 address:
kenv vfs.root.mountfrom=nfs:192.168.1.1:/share/name
reboot -r
SEE ALSO
kenv(1), getutxent(3), ipmi(4), boot(8), dumpon(8), nextboot(8),
savecore(8), shutdown(8), sync(8)
HISTORY
A reboot utility appeared in 4.0BSD.
FreeBSD 14.0-RELEASE-p11 December 20, 2017 FreeBSD 14.0-RELEASE-p11