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

     loader.4th - loader.conf processing tools

     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 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

           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

           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

           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.

     /boot/loader      The loader(8).
     /boot/loader.4th  loader.4th itself.
     /boot/loader.rc   loader(8) bootstrapping script.
                       File loaded by the start command.

     Standard /boot/loader.rc:

           include /boot/loader.4th

     Load a different kernel with the standard configuration:

           set kernel="kernel.old"

     Read an additional configuration file and then proceed to boot:

           read-conf /boot/special.conf

     Disable the loading of the splash screen module and bitmap and then
     proceed to boot:

           disable-module splash_bmp
           disable-module bitmap

     loader.conf(5), loader(8)

     The loader.4th set of commands first appeared in FreeBSD 3.2.

     The loader.4th set of commands was written by Daniel C. Sobral
     <[email protected]>.

     A British espionage series.

FreeBSD 11.1-RELEASE-p4        November 13, 2013       FreeBSD 11.1-RELEASE-p4
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