NAME
boot.cfg
- configuration file for /boot
DESCRIPTION
The file
/boot.cfg
is used to alter the behaviour of the standard boot loader described in
boot(8).
Configuration changes include setting the timeout, choosing a console device,
altering the banner text and displaying a menu allowing boot commands to be
easily chosen.
If a
boot.cfg
file is not present, the system will boot as normal.
The format of the file is a series of lines containing keyword/value pairs
separated by an equals sign
(`=').
There should be no whitespace surrounding the equals sign.
Lines beginning with a hash
(`#')
are comments and will be ignored.
Some keywords can be present multiple times in the file to define additional
items.
Such keywords are noted below.
- banner
-
(may be present multiple times)
The text from banner lines is displayed instead of the standard welcome text
by the boot loader.
Up to 10 lines can be defined.
No special character sequences are recognised, so to specify a blank line, a
banner line with no value should be given.
- menu
-
(may be present multiple times)
Used to define a menu item to be displayed to the end-user at boot time
which allows a series of boot commands to be run without further typing.
The value consists of the required menu text, followed by a colon
(`:')
and then the desired command(s).
Multiple commands can be specified separated by a semi-colon.
If the specified menu text is empty
(the colon appears immediately after the equals sign),
then the displayed menu text is the same as the command.
For example:
menu=Boot normally:boot
menu=Boot single-user:boot -s
menu=Boot with module foo:load /foo.kmod;boot
menu=Boot with serial console:consdev com0;boot
menu=:boot hd1a:netbsd -as
Each menu item will be prefixed by an ascending number when displayed,
i.e. the order in the
boot.cfg
file is important.
Each command is executed just as though the user had typed it in
and so can be any valid command that would be accepted at the
normal boot prompt.
In addition,
``prompt''
can be used to drop to the normal boot prompt.
- timeout
-
If the value is greater than zero, this specifies the time in seconds
that the boot loader will wait for the end-user to choose a menu item.
During the countdown period, they may press Return to choose the default
option or press a number key corresponding to a menu option.
If any other key is pressed, the countdown will stop and the user will be
prompted to choose a menu option with no further time limit.
If the timeout value is set to zero, the default option will be booted
immediately.
If the timeout value is negative or is not a number, there will be no
time limit for the user to choose an option.
- default
-
Used to specify the default menu item which will be chosen in the case of
Return being pressed or the timeout timer reaching zero.
The value is the number of the menu item as displayed.
As described above, the menu items are counted from 1 in the order listed in
.
If not specified, the default value will be option 1, i.e. the first item.
- consdev
-
Changes the console device to that specified in the value.
Valid values are any of those that could be specified at the normal boot
prompt with the consdev command.
- load
-
Used to load kernel modules, which will be passed on to the kernel for
initialization during early boot.
The argument is the complete path and file name of the module to be loaded.
May be used as many times as needed.
- format
-
Changes how the menu options are displayed.
Should be set to one of
`a'
for automatic,
`l'
for letters and
`n'
for numbers.
If set to automatic (the default), menu options will be displayed numerically
unless there are more than 9 options and the timeout is greater than zero.
If there are more than 9 options with a timeout greater than zero and
the format is set to number, only the first 9 options will be available.
EXAMPLES
Here is an example
boot.cfg
file:
-
banner=Welcome to NetBSD
banner==================
banner=
banner=Please choose an option from the following menu:
menu=Boot normally:boot
menu=Boot single-user:boot -s
menu=Boot from second disk:boot hd1a:
menu=Boot with module foo:load /foo.kmod;boot
menu=Boot with modules foo and bar:load /foo.kmod;load /bar.kmod;boot
menu=Boot Xen with 256MB for dom0:load /netbsd-XEN3_DOM0 console=pc;multiboot /usr/pkg/xen3-kernel/xen.gz dom0_mem=256M
menu=Boot Xen with 256MB for dom0 (serial):load /netbsd-XEN3_DOM0 console=com0;multiboot /usr/pkg/xen3-kernel/xen.gz dom0_mem=256M console=com1 com1=115200,8n1
menu=Boot Xen with dom0 in single-user mode:load /netbsd-XEN3_DOM0 -s;multiboot /usr/pkg/xen3-kernel/xen.gz dom0_mem=256M
menu=Go to command line (advanced users only):prompt
timeout=-1
default=1
# Always load ramdisk module
load=/miniroot.kmod
N.B. Xen counts serial ports from com1 upwards, but
NetBSD
counts from com0, so the appropriate device name must be used.
Please see the Xen with serial console example above.
This will display:
-
Welcome to NetBSD
=================
Please choose an option from the following menu:
1. Boot normally
2. Boot single-user
3. Boot from second disk
4. Boot with module foo
5. Boot with modules foo and bar
6. Boot Xen with 256 MB for dom0
7. Boot Xen with 256 MB for dom0 (serial)
8. Boot Xen with dom0 in single-user mode
9. Go to command line (advanced users only)
Option [1]:
It will then wait for the user to type 1, 2, 3, 4, 5, 6, 7, 8 or 9 followed by
Return.
Pressing Return by itself will run option 1.
There will be no timeout.
SEE ALSO
boot(8)
HISTORY
The
boot.cfg
utility appeared in
NetBSD5.0.
AUTHORS
The
boot.cfg
extensions to
boot(8)
were written by
Stephen Borrill
<sborrill@NetBSD.org>.
BUGS
Support for
boot.cfg
is currently for
NetBSD/i386
and
NetBSD/amd64
only.
It is hoped that its use will be extended to other appropriate ports that
use the
boot(8)
interface.