BOOT.CFG(5)               NetBSD File Formats Manual               BOOT.CFG(5)

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 display-
     ing a menu allowing boot commands to be easily chosen.  If a boot.cfg
     file is not present, the system will boot as normal.

   FILE FORMAT
     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 com-
     ments and will be ignored.

     Some keywords can be present multiple times in the file to define addi-
     tional 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 con-
              sists 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 dis-
              played, 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 corre-
              sponding 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 boot.cfg.  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 ker-
              nel 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 dis-
              played 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 num-
              ber, 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 fol-
     lowed 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 NetBSD 5.0.

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.

NetBSD 5.0.1                   November 18, 2008                  NetBSD 5.0.1

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