NEXTBOOT(8) FreeBSD System Manager's Manual NEXTBOOT(8)
NAME
nextboot - specify an alternate kernel and boot flags for the next reboot
SYNOPSIS
nextboot [-af] [-e variable=value] [-k kernel] [-o options]
nextboot -D
DESCRIPTION
The nextboot utility allows specifying some combination of an alternate
kernel, boot flags, and kernel environment for the next time the machine
is booted. Once the loader(8) loads in the new kernel information from
the /boot/nextboot.conf file, it is disabled so in case the new kernel
hangs the machine, once it is rebooted, the machine will automatically
revert to its previous configuration.
The options are as follows:
-a This option causes nextboot to append to an existing
configuration in /boot/nextboot.conf. By default any
existing configuration is overwritten.
-D Invoking nextboot with this option removes an existing
nextboot configuration.
-e variable=value
This option adds the provided variable and value to the
kernel environment. The value is quoted when written to
the nextboot configuration.
-f This option disables the sanity checking which checks if
the kernel really exists before writing the nextboot
configuration.
-k kernel This option specifies a kernel directory relative to /boot
to load the kernel and any modules from.
-o options This option allows the passing of kernel flags for the next
boot.
FILES
/boot/nextboot.conf The configuration file that the nextboot
configuration is written into.
EXAMPLES
To boot the GENERIC kernel with the nextboot command:
nextboot -k GENERIC
To enable into single user mode with the normal kernel:
nextboot -o "-s" -k kernel
To remove an existing nextboot configuration:
nextboot -D
SEE ALSO
boot(8), freebsd-update(8), loader(8)
HISTORY
The original nextboot manual page first appeared in FreeBSD 2.2. It used
a very different interface to achieve similar results.
The current incarnation of nextboot appeared in FreeBSD 5.0.
AUTHORS
This manual page was written by Gordon Tetlow <
[email protected]>.
BUGS
The nextboot code is implemented in the loader(8). It is not the most
thoroughly tested code. It is also my first attempt to write in Forth.
Finally, it does some evil things like writing to the file system before
it has been checked. If it scrambles your file system, do not blame me.
FreeBSD 14.1-RELEASE-p8 March 29, 2022 FreeBSD 14.1-RELEASE-p8