LOADER.4TH(8)

NAME
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 commands 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 <dcs@FreeBSD.org>.

BUGS
A British espionage series.