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144 lines
3.9 KiB
Groff
144 lines
3.9 KiB
Groff
.\" Copyright (c) 2002 Gordon Tetlow
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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 April 9, 2016
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.Dt NEXTBOOT 8
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.Os
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.Sh NAME
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.Nm nextboot
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.Nd "specify an alternate kernel and boot flags for the next reboot"
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.Sh SYNOPSIS
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.Nm
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.Op Fl af
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.Op Fl e Ar variable=value
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.Op Fl k Ar kernel
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.Op Fl o Ar options
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.Nm
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.Fl D
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.Sh DESCRIPTION
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The
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.Nm
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utility allows specifying some combination of an alternate kernel, boot flags
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and kernel environment for the
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next time the machine is booted.
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Once the
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.Xr loader 8
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loads in the new kernel
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information, it is deleted so in case the new kernel hangs the machine,
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once it is rebooted, the machine will automatically revert to its previous
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configuration.
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.Pp
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The options are as follows:
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.Bl -tag -width ".Fl o Ar options"
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.It Fl a
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This option causes
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.Nm
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to append to an existing configuration in
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.Pa /boot/nextboot.conf .
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By default any existing configuration is overwritten.
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.It Fl D
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Invoking
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.Nm
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with this
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option removes an existing
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.Nm
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configuration.
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.It Fl e Ar variable=value
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This option adds the provided variable and value to the kernel environment.
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The value is quoted when written to the
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.Nm
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configuration.
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.It Fl f
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This
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option disables the sanity checking which checks if the kernel really exists
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before writing the
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.Nm
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configuration.
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.It Fl k Ar kernel
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This option specifies a kernel directory relative to
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.Pa /boot
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to load the kernel and any modules from.
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.It Fl o Ar options
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This option
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allows the passing of kernel flags for the next boot.
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.El
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.Sh FILES
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.Bl -tag -width ".Pa /boot/nextboot.conf" -compact
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.It Pa /boot/nextboot.conf
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The configuration file that the
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.Nm
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configuration is written into.
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.El
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.Sh EXAMPLES
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To boot the
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.Pa GENERIC
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kernel with the
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.Nm
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command:
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.Pp
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.Dl "nextboot -k GENERIC"
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.Pp
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To enable into single user mode with the normal kernel:
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.Pp
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.Dl "nextboot -o ""-s"" -k kernel"
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.Pp
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To remove an existing nextboot configuration:
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.Pp
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.Dl "nextboot -D"
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.Sh SEE ALSO
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.Xr boot 8 ,
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.Xr loader 8
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.Sh HISTORY
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The original
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.Nm
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manual page first appeared in
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.Fx 2.2 .
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It used a very different interface to achieve similar results.
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.Pp
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The current incarnation of
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.Nm
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appeared in
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.Fx 5.0 .
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.Sh AUTHORS
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This manual page was written by
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.An Gordon Tetlow Aq Mt gordon@FreeBSD.org .
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.Sh BUGS
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The
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.Nm
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code is implemented in the
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.Xr loader 8 .
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It is not the most thoroughly tested code.
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It is also my first attempt to write in Forth.
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.Pp
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Finally, it does some evil things like writing to the file system before it
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has been checked.
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If it scrambles your file system, do not blame me.
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.Pp
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.Xr loader 8
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is only able to read ZFS, not write to it.
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.Pa nextboot.conf
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will NOT be reset in case of a kernel boot failure.
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