1.\" Copyright (c) 2002 Gordon Tetlow 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.\" Note: The date here should be updated whenever a non-trivial 28.\" change is made to the manual page. 29.Dd November 4, 2002 30.Dt NEXTBOOT 8 31.Os 32.Sh NAME 33.Nm nextboot 34.Nd specify an alternate kernel and boot flags for the next reboot 35.Sh SYNOPSIS 36.Nm 37.Op Fl f 38.Op Fl o Ar options 39.Fl k Ar kernel 40.Nm 41.Fl D 42.Sh DESCRIPTION 43The 44.Nm 45utility allows specifying an alternate kernel and/or boot flags for the 46next time the machine is booted. Once the loader loads in the new kernel 47information, it is deleted so in case the new kernel hangs the machine, 48once it is rebooted, the machine will automatically revert to its previous 49configuration. 50.Pp 51The options are as follows: 52.Bl -tag -width ".Fl o Ar options" 53.It Fl D 54Invoking 55.Nm 56with the 57.Fl D 58option removes an existing nextboot configuration. 59.It Fl f 60The 61.Fl f 62option disables the sanity checking which checks if the kernel really exists 63before writing the nextboot configuration. 64.It Fl k Ar kernel 65The 66.Fl k 67option with required kernel argument specifies a kernel directory relative to 68.Pa /boot 69to load the kernel and any modules from. 70.It Fl o Ar options 71The 72.Fl o 73allows the passing of kernel flags for the nextboot. 74.El 75.Sh FILES 76.Bl -tag -width ".Pa /boot/nextboot.conf" -compact 77.It Pa /boot/nextboot.conf 78The configuration file that the nextboot configuration is written into. 79.El 80.Sh EXAMPLES 81To boot the GENERIC kernel with the 82.Nm 83command: 84.Pp 85.Dl "nextboot -k GENERIC" 86.Pp 87To enable into single user mode with the normal kernel: 88.Pp 89.Dl "nextboot -o ""-s"" -k kernel" 90.Pp 91To remove an existing nextboot configuration: 92.Pp 93.Dl "nextboot -D" 94.Sh SEE ALSO 95.Xr boot 8 , 96.Xr loader 8 97.Sh HISTORY 98The original 99.Nm 100manual page first appeared in 101.Fx 2.2 . 102It used a very different interface to achieve similar results. 103.Pp 104The current incarnation of 105.Nm 106appeared in 107.Fx 5.0 . 108.Sh AUTHORS 109This manual page was written by 110.An Gordon Tetlow Aq gordon@FreeBSD.org . 111.Sh BUGS 112The nextboot code is implemented in the loader. It is not the most throughly 113tested code. It is also my first attempt to write in Forth. 114.Pp 115Finally, it does some evil things like writing to the filesystem before it 116has been checked. If it scrambles your filesystem, don't blame me. 117