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nextboot(8) [freebsd man page]

NEXTBOOT(8)						    BSD System Manager's Manual 					       NEXTBOOT(8)

nextboot -- specify an alternate kernel and boot flags for the next reboot SYNOPSIS
nextboot [-e variable=value] [-f] [-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, it is deleted 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: -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), 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 <>. 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. BSD
January 31, 2012 BSD

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LOADER.4TH(8)						    BSD System Manager's Manual 					     LOADER.4TH(8)

loader.4th -- loader.conf processing tools DESCRIPTION
The file that goes by the name of loader.4th is a set of commands designed to manipulate loader.conf(5) files. The default /boot/loader.rc includes loader.4th and uses one of its commands to automatically read and process the standard loader.conf(5) files. Other commands exists to help the user specify alternate configurations. The commands of loader.4th by themselves are not enough for most uses. Please refer to the examples below for the most common situations, and to loader(8) for additional commands. Before using any of the commands provided in loader.4th, it must be included through the command: include loader.4th This line is present in the default /boot/loader.rc file, so it is not needed (and should not be re-issued) in a normal setup. The commands provided by it are: boot boot kernelname [...] boot directory [...] boot -flag ... Boot as specified by the loader.conf(5) files read. Depending on the arguments passed, it can override boot flags and either the kernel name or the search path for kernel and modules. boot-conf boot-conf kernelname [...] boot-conf directory [...] boot-conf -flag ... Works like boot described above, but instead of booting immediately, uses autoboot, so it can be stopped. start Reads /boot/defaults/loader.conf, all other loader.conf(5) files specified in it, then loads the desired kernel and modules (if not already loaded). After which you can use the boot or autoboot commmands or simply exit (provided autoboot_delay is not set to NO) to boot the system. start is the command used in the default /boot/loader.rc file (see loader(8)). initialize Initialize the support library so commands can be used without executing start first. Like start, it reads /boot/defaults/loader.conf and all other loader.conf(5) files specified in it (but does not load kernel or modules). Returns a flag on the stack to indicate if any configuration files were successfully loaded. read-conf filename Reads and processes a loader.conf(5) file. Does not proceed to boot. enable-module module Enables the loading of module. disable-module module Disables the loading of module. toggle-module module Toggles the loading of module on and off. show-module module Shows the information gathered in the loader.conf(5) files about the module module. retry Used inside loader.conf(5) files to specify the action after a module loading fails. ignore Used inside loader.conf(5) files to specify the action after a module loading fails. try-include file [file ...] Process script files if they exist. Each file, in turn, is completely read into memory, and then each of its lines is passed to the command line interpreter. If any error is returned by the interpreter, the try-include command aborts immediately, without reading any other files, and silently returns without error. FILES
/boot/loader The loader(8). /boot/loader.4th loader.4th itself. /boot/loader.rc loader(8) bootstrapping script. /boot/defaults/loader.conf File loaded by the start command. EXAMPLES
Standard /boot/loader.rc: include /boot/loader.4th start Load a different kernel with the standard configuration: set kernel="kernel.old" unload boot-conf Read an additional configuration file and then proceed to boot: unload read-conf /boot/special.conf boot-conf Disable the loading of the splash screen module and bitmap and then proceed to boot: unload disable-module splash_bmp disable-module bitmap boot-conf SEE ALSO
loader.conf(5), loader(8) HISTORY
The loader.4th set of commands first appeared in FreeBSD 3.2. AUTHORS
The loader.4th set of commands was written by Daniel C. Sobral <>. BUGS
A British espionage series. BSD
November 13, 2013 BSD

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