1077 lines
28 KiB
Groff
1077 lines
28 KiB
Groff
.\" Copyright (c) 1999 Daniel C. Sobral
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd January 7, 2012
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.Dt LOADER 8
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.Os
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.Sh NAME
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.Nm loader
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.Nd kernel bootstrapping final stage
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.Sh DESCRIPTION
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The program called
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.Nm
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is the final stage of
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.Fx Ns 's
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kernel bootstrapping process.
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On IA32 (i386) architectures, it is a
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.Pa BTX
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client.
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It is linked statically to
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.Xr libstand 3
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and usually located in the directory
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.Pa /boot .
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.Pp
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It provides a scripting language that can be used to
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automate tasks, do pre-configuration or assist in recovery
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procedures.
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This scripting language is roughly divided in
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two main components.
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The smaller one is a set of commands
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designed for direct use by the casual user, called "builtin
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commands" for historical reasons.
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The main drive behind these commands is user-friendliness.
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The bigger component is an
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.Tn ANS
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Forth compatible Forth interpreter based on FICL, by
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.An John Sadler .
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.Pp
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During initialization,
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.Nm
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will probe for a console and set the
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.Va console
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variable, or set it to serial console
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.Pq Dq Li comconsole
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if the previous boot stage used that.
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If multiple consoles are selected, they will be listed separated by spaces.
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Then, devices are probed,
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.Va currdev
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and
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.Va loaddev
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are set, and
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.Va LINES
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is set to 24.
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Next,
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.Tn FICL
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is initialized, the builtin words are added to its vocabulary, and
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.Pa /boot/boot.4th
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is processed if it exists.
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No disk switching is possible while that file is being read.
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The inner interpreter
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.Nm
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will use with
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.Tn FICL
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is then set to
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.Ic interpret ,
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which is
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.Tn FICL Ns 's
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default.
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After that,
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.Pa /boot/loader.rc
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is processed if available, and, failing that,
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.Pa /boot/boot.conf
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is read for historical reasons.
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These files are processed through the
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.Ic include
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command, which reads all of them into memory before processing them,
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making disk changes possible.
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.Pp
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At this point, if an
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.Ic autoboot
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has not been tried, and if
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.Va autoboot_delay
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is not set to
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.Dq Li NO
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(not case sensitive), then an
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.Ic autoboot
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will be tried.
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If the system gets past this point,
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.Va prompt
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will be set and
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.Nm
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will engage interactive mode.
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Please note that historically even when
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.Va autoboot_delay
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is set to
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.Dq Li 0
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user will be able to interrupt autoboot process by pressing some key
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on the console while kernel and modules are being loaded.
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In some
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cases such behaviour may be undesirable, to prevent it set
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.Va autoboot_delay
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to
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.Dq Li -1 ,
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in this case
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.Nm
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will engage interactive mode only if
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.Ic autoboot
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has failed.
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.Sh BUILTIN COMMANDS
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In
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.Nm ,
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builtin commands take parameters from the command line.
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Presently,
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the only way to call them from a script is by using
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.Pa evaluate
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on a string.
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If an error condition occurs, an exception will be generated,
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which can be intercepted using
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.Tn ANS
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Forth exception handling
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words.
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If not intercepted, an error message will be displayed and
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the interpreter's state will be reset, emptying the stack and restoring
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interpreting mode.
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.Pp
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The builtin commands available are:
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.Pp
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.Bl -tag -width Ds -compact
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.It Ic autoboot Op Ar seconds Op Ar prompt
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Proceeds to bootstrap the system after a number of seconds, if not
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interrupted by the user.
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Displays a countdown prompt
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warning the user the system is about to be booted,
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unless interrupted by a key press.
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The kernel will be loaded first if necessary.
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Defaults to 10 seconds.
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.Pp
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.It Ic bcachestat
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Displays statistics about disk cache usage.
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For debugging only.
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.Pp
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.It Ic boot
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.It Ic boot Ar kernelname Op Cm ...
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.It Ic boot Fl flag Cm ...
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Immediately proceeds to bootstrap the system, loading the kernel
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if necessary.
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Any flags or arguments are passed to the kernel, but they
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must precede the kernel name, if a kernel name is provided.
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.Pp
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.Em WARNING :
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The behavior of this builtin is changed if
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.Xr loader.4th 8
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is loaded.
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.Pp
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.It Ic echo Xo
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.Op Fl n
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.Op Aq message
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.Xc
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Displays text on the screen.
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A new line will be printed unless
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.Fl n
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is specified.
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.Pp
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.It Ic heap
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Displays memory usage statistics.
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For debugging purposes only.
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.Pp
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.It Ic help Op topic Op subtopic
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Shows help messages read from
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.Pa /boot/loader.help .
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The special topic
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.Em index
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will list the topics available.
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.Pp
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.It Ic include Ar file Op Ar
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Process script files.
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Each file, in turn, is completely read into memory,
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and then each of its lines is passed to the command line interpreter.
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If any error is returned by the interpreter, the include
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command aborts immediately, without reading any other files, and
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returns an error itself (see
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.Sx ERRORS ) .
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.Pp
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.It Ic load Xo
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.Op Fl t Ar type
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.Ar file Cm ...
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.Xc
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Loads a kernel, kernel loadable module (kld), or file of opaque
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contents tagged as being of the type
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.Ar type .
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Kernel and modules can be either in a.out or ELF format.
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Any arguments passed after the name of the file to be loaded
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will be passed as arguments to that file.
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Currently, argument passing does not work for the kernel.
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.Pp
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.It Ic load_geli Xo
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.Op Fl n Ar keyno
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.Ar prov Ar file
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.Xc
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Loads a
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.Xr geli 8
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encryption keyfile for the given provider name.
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The key index can be specified via
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.Ar keyno
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or will default to zero.
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.Pp
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.It Ic ls Xo
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.Op Fl l
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.Op Ar path
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.Xc
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Displays a listing of files in the directory
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.Ar path ,
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or the root directory if
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.Ar path
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is not specified.
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If
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.Fl l
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is specified, file sizes will be shown too.
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.Pp
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.It Ic lsdev Op Fl v
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Lists all of the devices from which it may be possible to load modules.
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If
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.Fl v
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is specified, more details are printed.
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.Pp
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.It Ic lsmod Op Fl v
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Displays loaded modules.
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If
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.Fl v
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is specified, more details are shown.
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.Pp
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.It Ic more Ar file Op Ar
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Display the files specified, with a pause at each
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.Va LINES
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displayed.
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.Pp
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.It Ic pnpscan Op Fl v
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Scans for Plug-and-Play devices.
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This is not functional at present.
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.Pp
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.It Ic read Xo
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.Op Fl t Ar seconds
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.Op Fl p Ar prompt
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.Op Va variable
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.Xc
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Reads a line of input from the terminal, storing it in
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.Va variable
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if specified.
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A timeout can be specified with
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.Fl t ,
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though it will be canceled at the first key pressed.
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A prompt may also be displayed through the
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.Fl p
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flag.
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.Pp
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.It Ic reboot
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Immediately reboots the system.
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.Pp
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.It Ic set Ar variable
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.It Ic set Ar variable Ns = Ns Ar value
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Set loader's environment variables.
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.Pp
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.It Ic show Op Va variable
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Displays the specified variable's value, or all variables and their
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values if
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.Va variable
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is not specified.
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.Pp
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.It Ic unload
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Remove all modules from memory.
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.Pp
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.It Ic unset Va variable
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Removes
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.Va variable
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from the environment.
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.Pp
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.It Ic \&?
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Lists available commands.
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.El
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.Ss BUILTIN ENVIRONMENT VARIABLES
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The
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.Nm
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has actually two different kinds of
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.Sq environment
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variables.
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There are ANS Forth's
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.Em environmental queries ,
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and a separate space of environment variables used by builtins, which
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are not directly available to Forth words.
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It is the latter type that this section covers.
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.Pp
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Environment variables can be set and unset through the
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.Ic set
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and
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.Ic unset
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builtins, and can have their values interactively examined through the
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use of the
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.Ic show
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builtin.
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Their values can also be accessed as described in
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.Sx BUILTIN PARSER .
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.Pp
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Notice that these environment variables are not inherited by any shell
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after the system has been booted.
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.Pp
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A few variables are set automatically by
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.Nm .
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Others can affect the behavior of either
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.Nm
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or the kernel at boot.
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Some options may require a value,
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while others define behavior just by being set.
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Both types of builtin variables are described below.
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.Bl -tag -width bootfile
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.It Va autoboot_delay
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Number of seconds
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.Ic autoboot
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will wait before booting.
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If this variable is not defined,
|
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.Ic autoboot
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will default to 10 seconds.
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.Pp
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If set to
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.Dq Li NO ,
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no
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.Ic autoboot
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will be automatically attempted after processing
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.Pa /boot/loader.rc ,
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though explicit
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.Ic autoboot Ns 's
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will be processed normally, defaulting to 10 seconds delay.
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.Pp
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If set to
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.Dq Li 0 ,
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no delay will be inserted, but user still will be able to interrupt
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.Ic autoboot
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process and escape into the interactive mode by pressing some key
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on the console while kernel and
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modules are being loaded.
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.Pp
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If set to
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.Dq Li -1 ,
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no delay will be inserted and
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.Nm
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will engage interactive mode only if
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.Ic autoboot
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has failed for some reason.
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.It Va boot_askname
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Instructs the kernel to prompt the user for the name of the root device
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when the kernel is booted.
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.It Va boot_cdrom
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Instructs the kernel to try to mount the root file system from CD-ROM.
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.It Va boot_ddb
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Instructs the kernel to start in the DDB debugger, rather than
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proceeding to initialize when booted.
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.It Va boot_dfltroot
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Instructs the kernel to mount the statically compiled-in root file system.
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.It Va boot_gdb
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Selects gdb-remote mode for the kernel debugger by default.
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.It Va boot_multicons
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Enables multiple console support in the kernel early on boot.
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In a running system, console configuration can be manipulated
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by the
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.Xr conscontrol 8
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utility.
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.It Va boot_mute
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All console output is suppressed when console is muted.
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In a running system, the state of console muting can be manipulated by the
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.Xr conscontrol 8
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utility.
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.It Va boot_pause
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During the device probe, pause after each line is printed.
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.It Va boot_serial
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Force the use of a serial console even when an internal console
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is present.
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.It Va boot_single
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Prevents the kernel from initiating a multi-user startup; instead,
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a single-user mode will be entered when the kernel has finished
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device probing.
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.It Va boot_verbose
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Setting this variable causes extra debugging information to be printed
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by the kernel during the boot phase.
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.It Va bootfile
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List of semicolon-separated search path for bootable kernels.
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The default is
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.Dq Li kernel .
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.It Va comconsole_speed
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Defines the speed of the serial console (i386 and amd64 only).
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If the previous boot stage indicated that a serial console is in use
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then this variable is initialized to the current speed of the console
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serial port.
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Otherwise it is set to 9600 unless this was overridden using the
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.Va BOOT_COMCONSOLE_SPEED
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variable when
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.Nm
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was compiled.
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Changes to the
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.Va comconsole_speed
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variable take effect immediately.
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.It Va comconsole_port
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Defines the base i/o port used to access console UART
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(i386 and amd64 only).
|
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If the variable is not set, its assumed value is 0x3F8, which
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corresponds to PC port COM1, unless overridden by
|
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.Va BOOT_COMCONSOLE_PORT
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variable during the compilation of
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.Nm .
|
|
Setting the
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.Va comconsole_port
|
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variable automatically set
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.Va hw.uart.console
|
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environment variable to provide a hint to kernel for location of the console.
|
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Loader console is changed immediately after variable
|
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.Va comconsole_port
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is set.
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.It Va comconsole_pcidev
|
|
Defines the location of a PCI device of the 'simple communication'
|
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class to be used as the serial console UART (i386 and amd64 only).
|
|
The syntax of the variable is
|
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.Li 'bus:device:function[:bar]' ,
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|
where all members must be numeric, with possible
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.Li 0x
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prefix to indicate a hexadecimal value.
|
|
The
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.Va bar
|
|
member is optional and assumed to be 0x10 if omitted.
|
|
The bar must decode i/o space.
|
|
Setting the variable
|
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.Va comconsole_pcidev
|
|
automatically sets the variable
|
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.Va comconsole_port
|
|
to the base of the selected bar, and hint
|
|
.Va hw.uart.console .
|
|
Loader console is changed immediately after variable
|
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.Va comconsole_pcidev
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is set.
|
|
.It Va console
|
|
Defines the current console or consoles.
|
|
Multiple consoles may be specified.
|
|
In that case, the first listed console will become the default console for
|
|
userland output (e.g.\& from
|
|
.Xr init 8 ) .
|
|
.It Va currdev
|
|
Selects the default device.
|
|
Syntax for devices is odd.
|
|
.It Va init_chroot
|
|
If set to a valid directory in the root file system, it causes
|
|
.Xr init 8
|
|
to perform a
|
|
.Xr chroot 2
|
|
operation on that directory, making it the new root directory.
|
|
That happens before entering single-user mode or multi-user
|
|
mode (but after executing the
|
|
.Va init_script
|
|
if enabled).
|
|
.It Va init_path
|
|
Sets the list of binaries which the kernel will try to run as the initial
|
|
process.
|
|
The first matching binary is used.
|
|
The default list is
|
|
.Dq Li /sbin/init:/sbin/oinit:/sbin/init.bak:\:/rescue/init .
|
|
.It Va init_script
|
|
If set to a valid file name in the root file system,
|
|
instructs
|
|
.Xr init 8
|
|
to run that script as the very first action,
|
|
before doing anything else.
|
|
Signal handling and exit code interpretation is similar to
|
|
running the
|
|
.Pa /etc/rc
|
|
script.
|
|
In particular, single-user operation is enforced
|
|
if the script terminates with a non-zero exit code,
|
|
or if a SIGTERM is delivered to the
|
|
.Xr init 8
|
|
process (PID 1).
|
|
.It Va init_shell
|
|
Defines the shell binary to be used for executing the various shell scripts.
|
|
The default is
|
|
.Dq Li /bin/sh .
|
|
It is used for running the
|
|
.Va init_script
|
|
if set, as well as for the
|
|
.Pa /etc/rc
|
|
and
|
|
.Pa /etc/rc.shutdown
|
|
scripts.
|
|
The value of the corresponding
|
|
.Xr kenv 2
|
|
variable is evaluated every time
|
|
.Xr init 8
|
|
calls a shell script, so it can be changed later on using the
|
|
.Xr kenv 1
|
|
utility.
|
|
In particular, if a non-default shell is used for running an
|
|
.Va init_script ,
|
|
it might be desirable to have that script reset the value of
|
|
.Va init_shell
|
|
back to the default, so that the
|
|
.Pa /etc/rc
|
|
script is executed with the standard shell
|
|
.Pa /bin/sh .
|
|
.It Va interpret
|
|
Has the value
|
|
.Dq Li OK
|
|
if the Forth's current state is interpreting.
|
|
.It Va LINES
|
|
Define the number of lines on the screen, to be used by the pager.
|
|
.It Va module_path
|
|
Sets the list of directories which will be searched for modules
|
|
named in a load command or implicitly required by a dependency.
|
|
The default value for this variable is
|
|
.Dq Li /boot/kernel;/boot/modules .
|
|
.It Va num_ide_disks
|
|
Sets the number of IDE disks as a workaround for some problems in
|
|
finding the root disk at boot.
|
|
This has been deprecated in favor of
|
|
.Va root_disk_unit .
|
|
.It Va prompt
|
|
Value of
|
|
.Nm Ns 's
|
|
prompt.
|
|
Defaults to
|
|
.Dq Li "${interpret}" .
|
|
If variable
|
|
.Va prompt
|
|
is unset, the default prompt is
|
|
.Ql > .
|
|
.It Va root_disk_unit
|
|
If the code which detects the disk unit number for the root disk is
|
|
confused, e.g.\& by a mix of SCSI and IDE disks, or IDE disks with
|
|
gaps in the sequence (e.g.\& no primary slave), the unit number can
|
|
be forced by setting this variable.
|
|
.It Va rootdev
|
|
By default the value of
|
|
.Va currdev
|
|
is used to set the root file system
|
|
when the kernel is booted.
|
|
This can be overridden by setting
|
|
.Va rootdev
|
|
explicitly.
|
|
.El
|
|
.Pp
|
|
Other variables are used to override kernel tunable parameters.
|
|
The following tunables are available:
|
|
.Bl -tag -width Va
|
|
.It Va hw.physmem
|
|
Limit the amount of physical memory the system will use.
|
|
By default the size is in bytes, but the
|
|
.Cm k , K , m , M , g
|
|
and
|
|
.Cm G
|
|
suffixes
|
|
are also accepted and indicate kilobytes, megabytes and gigabytes
|
|
respectively.
|
|
An invalid suffix will result in the variable being ignored by the
|
|
kernel.
|
|
.It Va hw.pci.host_start_mem , hw.acpi.host_start_mem
|
|
When not otherwise constrained, this limits the memory start
|
|
address.
|
|
The default is 0x80000000 and should be set to at least size of the
|
|
memory and not conflict with other resources.
|
|
Typically, only systems without PCI bridges need to set this variable
|
|
since PCI bridges typically constrain the memory starting address
|
|
(and the variable is only used when bridges do not constrain this
|
|
address).
|
|
.It Va hw.pci.enable_io_modes
|
|
Enable PCI resources which are left off by some BIOSes or are not
|
|
enabled correctly by the device driver.
|
|
Tunable value set to ON (1) by default, but this may cause problems
|
|
with some peripherals.
|
|
.It Va kern.maxusers
|
|
Set the size of a number of statically allocated system tables; see
|
|
.Xr tuning 7
|
|
for a description of how to select an appropriate value for this
|
|
tunable.
|
|
When set, this tunable replaces the value declared in the kernel
|
|
compile-time configuration file.
|
|
.It Va kern.ipc.nmbclusters
|
|
Set the number of mbuf clusters to be allocated.
|
|
The value cannot be set below the default
|
|
determined when the kernel was compiled.
|
|
.It Va kern.ipc.nsfbufs
|
|
Set the number of
|
|
.Xr sendfile 2
|
|
buffers to be allocated.
|
|
Overrides
|
|
.Dv NSFBUFS .
|
|
Not all architectures use such buffers; see
|
|
.Xr sendfile 2
|
|
for details.
|
|
.It Va kern.maxswzone
|
|
Limits the amount of KVM to be used to hold swap
|
|
metadata, which directly governs the
|
|
maximum amount of swap the system can support,
|
|
at the rate of approximately 200 MB of swap space
|
|
per 1 MB of metadata.
|
|
This value is specified in bytes of KVA space.
|
|
If no value is provided, the system allocates
|
|
enough memory to handle an amount of swap
|
|
that corresponds to eight times the amount of
|
|
physical memory present in the system.
|
|
.Pp
|
|
Note that swap metadata can be fragmented,
|
|
which means that the system can run out of
|
|
space before it reaches the theoretical limit.
|
|
Therefore, care should be taken to not configure
|
|
more swap than approximately half of the
|
|
theoretical maximum.
|
|
.Pp
|
|
Running out of space for swap metadata can leave
|
|
the system in an unrecoverable state.
|
|
Therefore, you should only change
|
|
this parameter if you need to greatly extend the
|
|
KVM reservation for other resources such as the
|
|
buffer cache or
|
|
.Va kern.ipc.nmbclusters .
|
|
Modifies kernel option
|
|
.Dv VM_SWZONE_SIZE_MAX .
|
|
.It Va kern.maxbcache
|
|
Limits the amount of KVM reserved for use by the
|
|
buffer cache, specified in bytes.
|
|
The default maximum is 200MB on i386,
|
|
and 400MB on amd64 and sparc64.
|
|
This parameter is used to
|
|
prevent the buffer cache from eating too much
|
|
KVM in large-memory machine configurations.
|
|
Only mess around with this parameter if you need to
|
|
greatly extend the KVM reservation for other resources
|
|
such as the swap zone or
|
|
.Va kern.ipc.nmbclusters .
|
|
Note that
|
|
the NBUF parameter will override this limit.
|
|
Modifies
|
|
.Dv VM_BCACHE_SIZE_MAX .
|
|
.It Va kern.msgbufsize
|
|
Sets the size of the kernel message buffer.
|
|
The default limit of 64KB is usually sufficient unless
|
|
large amounts of trace data need to be collected
|
|
between opportunities to examine the buffer or
|
|
dump it to a file.
|
|
Overrides kernel option
|
|
.Dv MSGBUF_SIZE .
|
|
.It Va machdep.disable_mtrrs
|
|
Disable the use of i686 MTRRs (x86 only).
|
|
.It Va net.inet.tcp.tcbhashsize
|
|
Overrides the compile-time set value of
|
|
.Dv TCBHASHSIZE
|
|
or the preset default of 512.
|
|
Must be a power of 2.
|
|
.It Va vm.kmem_size
|
|
Sets the size of kernel memory (bytes).
|
|
This overrides the value determined when the kernel was compiled.
|
|
Modifies
|
|
.Dv VM_KMEM_SIZE .
|
|
.It Va vm.kmem_size_min
|
|
.It Va vm.kmem_size_max
|
|
Sets the minimum and maximum (respectively) amount of kernel memory
|
|
that will be automatically allocated by the kernel.
|
|
These override the values determined when the kernel was compiled.
|
|
Modifies
|
|
.Dv VM_KMEM_SIZE_MIN
|
|
and
|
|
.Dv VM_KMEM_SIZE_MAX .
|
|
.El
|
|
.Ss BUILTIN PARSER
|
|
When a builtin command is executed, the rest of the line is taken
|
|
by it as arguments, and it is processed by a special parser which
|
|
is not used for regular Forth commands.
|
|
.Pp
|
|
This special parser applies the following rules to the parsed text:
|
|
.Bl -enum
|
|
.It
|
|
All backslash characters are preprocessed.
|
|
.Bl -bullet
|
|
.It
|
|
\eb , \ef , \er , \en and \et are processed as in C.
|
|
.It
|
|
\es is converted to a space.
|
|
.It
|
|
\ev is converted to
|
|
.Tn ASCII
|
|
11.
|
|
.It
|
|
\ez is just skipped.
|
|
Useful for things like
|
|
.Dq \e0xf\ez\e0xf .
|
|
.It
|
|
\e0xN and \e0xNN are replaced by the hex N or NN.
|
|
.It
|
|
\eNNN is replaced by the octal NNN
|
|
.Tn ASCII
|
|
character.
|
|
.It
|
|
\e" , \e' and \e$ will escape these characters, preventing them from
|
|
receiving special treatment in Step 2, described below.
|
|
.It
|
|
\e\e will be replaced with a single \e .
|
|
.It
|
|
In any other occurrence, backslash will just be removed.
|
|
.El
|
|
.It
|
|
Every string between non-escaped quotes or double-quotes will be treated
|
|
as a single word for the purposes of the remaining steps.
|
|
.It
|
|
Replace any
|
|
.Li $VARIABLE
|
|
or
|
|
.Li ${VARIABLE}
|
|
with the value of the environment variable
|
|
.Va VARIABLE .
|
|
.It
|
|
Space-delimited arguments are passed to the called builtin command.
|
|
Spaces can also be escaped through the use of \e\e .
|
|
.El
|
|
.Pp
|
|
An exception to this parsing rule exists, and is described in
|
|
.Sx BUILTINS AND FORTH .
|
|
.Ss BUILTINS AND FORTH
|
|
All builtin words are state-smart, immediate words.
|
|
If interpreted, they behave exactly as described previously.
|
|
If they are compiled, though,
|
|
they extract their arguments from the stack instead of the command line.
|
|
.Pp
|
|
If compiled, the builtin words expect to find, at execution time, the
|
|
following parameters on the stack:
|
|
.D1 Ar addrN lenN ... addr2 len2 addr1 len1 N
|
|
where
|
|
.Ar addrX lenX
|
|
are strings which will compose the command line that will be parsed
|
|
into the builtin's arguments.
|
|
Internally, these strings are concatenated in from 1 to N,
|
|
with a space put between each one.
|
|
.Pp
|
|
If no arguments are passed, a 0
|
|
.Em must
|
|
be passed, even if the builtin accepts no arguments.
|
|
.Pp
|
|
While this behavior has benefits, it has its trade-offs.
|
|
If the execution token of a builtin is acquired (through
|
|
.Ic '
|
|
or
|
|
.Ic ['] ) ,
|
|
and then passed to
|
|
.Ic catch
|
|
or
|
|
.Ic execute ,
|
|
the builtin behavior will depend on the system state
|
|
.Bf Em
|
|
at the time
|
|
.Ic catch
|
|
or
|
|
.Ic execute
|
|
is processed!
|
|
.Ef
|
|
This is particularly annoying for programs that want or need to
|
|
handle exceptions.
|
|
In this case, the use of a proxy is recommended.
|
|
For example:
|
|
.Dl : (boot) boot ;
|
|
.Sh FICL
|
|
.Tn FICL
|
|
is a Forth interpreter written in C, in the form of a forth
|
|
virtual machine library that can be called by C functions and vice
|
|
versa.
|
|
.Pp
|
|
In
|
|
.Nm ,
|
|
each line read interactively is then fed to
|
|
.Tn FICL ,
|
|
which may call
|
|
.Nm
|
|
back to execute the builtin words.
|
|
The builtin
|
|
.Ic include
|
|
will also feed
|
|
.Tn FICL ,
|
|
one line at a time.
|
|
.Pp
|
|
The words available to
|
|
.Tn FICL
|
|
can be classified into four groups.
|
|
The
|
|
.Tn ANS
|
|
Forth standard words, extra
|
|
.Tn FICL
|
|
words, extra
|
|
.Fx
|
|
words, and the builtin commands;
|
|
the latter were already described.
|
|
The
|
|
.Tn ANS
|
|
Forth standard words are listed in the
|
|
.Sx STANDARDS
|
|
section.
|
|
The words falling in the two other groups are described in the
|
|
following subsections.
|
|
.Ss FICL EXTRA WORDS
|
|
.Bl -tag -width wid-set-super
|
|
.It Ic .env
|
|
.It Ic .ver
|
|
.It Ic -roll
|
|
.It Ic 2constant
|
|
.It Ic >name
|
|
.It Ic body>
|
|
.It Ic compare
|
|
This is the STRING word set's
|
|
.Ic compare .
|
|
.It Ic compile-only
|
|
.It Ic endif
|
|
.It Ic forget-wid
|
|
.It Ic parse-word
|
|
.It Ic sliteral
|
|
This is the STRING word set's
|
|
.Ic sliteral .
|
|
.It Ic wid-set-super
|
|
.It Ic w@
|
|
.It Ic w!
|
|
.It Ic x.
|
|
.It Ic empty
|
|
.It Ic cell-
|
|
.It Ic -rot
|
|
.El
|
|
.Ss FREEBSD EXTRA WORDS
|
|
.Bl -tag -width XXXXXXXX
|
|
.It Ic \&$ Pq --
|
|
Evaluates the remainder of the input buffer, after having printed it first.
|
|
.It Ic \&% Pq --
|
|
Evaluates the remainder of the input buffer under a
|
|
.Ic catch
|
|
exception guard.
|
|
.It Ic .#
|
|
Works like
|
|
.Ic "."
|
|
but without outputting a trailing space.
|
|
.It Ic fclose Pq Ar fd --
|
|
Closes a file.
|
|
.It Ic fkey Pq Ar fd -- char
|
|
Reads a single character from a file.
|
|
.It Ic fload Pq Ar fd --
|
|
Processes a file
|
|
.Em fd .
|
|
.It Ic fopen Pq Ar addr len mode Li -- Ar fd
|
|
Opens a file.
|
|
Returns a file descriptor, or \-1 in case of failure.
|
|
The
|
|
.Ar mode
|
|
parameter selects whether the file is to be opened for read access, write
|
|
access, or both.
|
|
The constants
|
|
.Dv O_RDONLY , O_WRONLY ,
|
|
and
|
|
.Dv O_RDWR
|
|
are defined in
|
|
.Pa /boot/support.4th ,
|
|
indicating read only, write only, and read-write access, respectively.
|
|
.It Xo
|
|
.Ic fread
|
|
.Pq Ar fd addr len -- len'
|
|
.Xc
|
|
Tries to read
|
|
.Em len
|
|
bytes from file
|
|
.Em fd
|
|
into buffer
|
|
.Em addr .
|
|
Returns the actual number of bytes read, or -1 in case of error or end of
|
|
file.
|
|
.It Ic heap? Pq -- Ar cells
|
|
Return the space remaining in the dictionary heap, in cells.
|
|
This is not related to the heap used by dynamic memory allocation words.
|
|
.It Ic inb Pq Ar port -- char
|
|
Reads a byte from a port.
|
|
.It Ic key Pq -- Ar char
|
|
Reads a single character from the console.
|
|
.It Ic key? Pq -- Ar flag
|
|
Returns
|
|
.Ic true
|
|
if there is a character available to be read from the console.
|
|
.It Ic ms Pq Ar u --
|
|
Waits
|
|
.Em u
|
|
microseconds.
|
|
.It Ic outb Pq Ar port char --
|
|
Writes a byte to a port.
|
|
.It Ic seconds Pq -- Ar u
|
|
Returns the number of seconds since midnight.
|
|
.It Ic tib> Pq -- Ar addr len
|
|
Returns the remainder of the input buffer as a string on the stack.
|
|
.It Ic trace! Pq Ar flag --
|
|
Activates or deactivates tracing.
|
|
Does not work with
|
|
.Ic catch .
|
|
.El
|
|
.Ss FREEBSD DEFINED ENVIRONMENTAL QUERIES
|
|
.Bl -tag -width Ds
|
|
.It arch-i386
|
|
.Ic TRUE
|
|
if the architecture is IA32.
|
|
.It FreeBSD_version
|
|
.Fx
|
|
version at compile time.
|
|
.It loader_version
|
|
.Nm
|
|
version.
|
|
.El
|
|
.Ss SYSTEM DOCUMENTATION
|
|
.Sh FILES
|
|
.Bl -tag -width /boot/defaults/loader.conf -compact
|
|
.It Pa /boot/loader
|
|
.Nm
|
|
itself.
|
|
.It Pa /boot/boot.4th
|
|
Additional
|
|
.Tn FICL
|
|
initialization.
|
|
.It Pa /boot/boot.conf
|
|
.Nm
|
|
bootstrapping script.
|
|
Deprecated.
|
|
.It Pa /boot/defaults/loader.conf
|
|
.It Pa /boot/loader.conf
|
|
.It Pa /boot/loader.conf.local
|
|
.Nm
|
|
configuration files, as described in
|
|
.Xr loader.conf 5 .
|
|
.It Pa /boot/loader.rc
|
|
.Nm
|
|
bootstrapping script.
|
|
.It Pa /boot/loader.help
|
|
Loaded by
|
|
.Ic help .
|
|
Contains the help messages.
|
|
.El
|
|
.Sh EXAMPLES
|
|
Boot in single user mode:
|
|
.Pp
|
|
.Dl boot -s
|
|
.Pp
|
|
Load the kernel, a splash screen, and then autoboot in five seconds.
|
|
Notice that a kernel must be loaded before any other
|
|
.Ic load
|
|
command is attempted.
|
|
.Bd -literal -offset indent
|
|
load kernel
|
|
load splash_bmp
|
|
load -t splash_image_data /boot/chuckrulez.bmp
|
|
autoboot 5
|
|
.Ed
|
|
.Pp
|
|
Set the disk unit of the root device to 2, and then boot.
|
|
This would be needed in a system with two IDE disks,
|
|
with the second IDE disk hardwired to ad2 instead of ad1.
|
|
.Bd -literal -offset indent
|
|
set root_disk_unit=2
|
|
boot /boot/kernel/kernel
|
|
.Ed
|
|
.Pp
|
|
See also:
|
|
.Bl -tag -width /usr/share/examples/bootforth/X
|
|
.It Pa /boot/loader.4th
|
|
Extra builtin-like words.
|
|
.It Pa /boot/support.4th
|
|
.Pa loader.conf
|
|
processing words.
|
|
.It Pa /usr/share/examples/bootforth/
|
|
Assorted examples.
|
|
.El
|
|
.Sh ERRORS
|
|
The following values are thrown by
|
|
.Nm :
|
|
.Bl -tag -width XXXXX -offset indent
|
|
.It 100
|
|
Any type of error in the processing of a builtin.
|
|
.It -1
|
|
.Ic Abort
|
|
executed.
|
|
.It -2
|
|
.Ic Abort"
|
|
executed.
|
|
.It -56
|
|
.Ic Quit
|
|
executed.
|
|
.It -256
|
|
Out of interpreting text.
|
|
.It -257
|
|
Need more text to succeed -- will finish on next run.
|
|
.It -258
|
|
.Ic Bye
|
|
executed.
|
|
.It -259
|
|
Unspecified error.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr libstand 3 ,
|
|
.Xr loader.conf 5 ,
|
|
.Xr tuning 7 ,
|
|
.Xr boot 8 ,
|
|
.Xr btxld 8
|
|
.Sh STANDARDS
|
|
For the purposes of ANS Forth compliance, loader is an
|
|
.Bf Em
|
|
ANS Forth System with Environmental Restrictions, Providing
|
|
.Ef
|
|
.Bf Li
|
|
.No .( ,
|
|
.No :noname ,
|
|
.No ?do ,
|
|
parse, pick, roll, refill, to, value, \e, false, true,
|
|
.No <> ,
|
|
.No 0<> ,
|
|
compile\&, , erase, nip, tuck
|
|
.Ef
|
|
.Em and
|
|
.Li marker
|
|
.Bf Em
|
|
from the Core Extensions word set, Providing the Exception Extensions
|
|
word set, Providing the Locals Extensions word set, Providing the
|
|
Memory-Allocation Extensions word set, Providing
|
|
.Ef
|
|
.Bf Li
|
|
\&.s,
|
|
bye, forget, see, words,
|
|
\&[if],
|
|
\&[else]
|
|
.Ef
|
|
.Em and
|
|
.Li [then]
|
|
.Bf Em
|
|
from the Programming-Tools extension word set, Providing the
|
|
Search-Order extensions word set.
|
|
.Ef
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
first appeared in
|
|
.Fx 3.1 .
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
The
|
|
.Nm
|
|
was written by
|
|
.An Michael Smith Aq msmith@FreeBSD.org .
|
|
.Pp
|
|
.Tn FICL
|
|
was written by
|
|
.An John Sadler Aq john_sadler@alum.mit.edu .
|
|
.Sh BUGS
|
|
The
|
|
.Ic expect
|
|
and
|
|
.Ic accept
|
|
words will read from the input buffer instead of the console.
|
|
The latter will be fixed, but the former will not.
|