LOADER.4TH(8)						    BSD System Manager's Manual 					     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 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 <dcs@FreeBSD.org>.

BUGS

     A British espionage series.

BSD
								 November 13, 2013							       BSD