update-grub - program to generate GRUB's menu.lst file
update-grub
update-grub is a program used to generate the
menu.lst file
used by the grub bootloader. It works by looking in
/boot for all files
which start with "
vmlinuz-". They will be treated as
kernels, and grub menu entries will be created for each. It will also create
the initial
menu.lst if none exists, after prompting the user. It will
also add initrd lines for ramdisk images found with the same version as
kernels found. e.g. /boot/vmlinuz-2.4.5 and /boot/initrd-2.4.5 will cause a
line of "initrd=/boot/initrd-2.4.5 or similar to be added for the kernel
entry in the menu.lst.
After
update-grub has been run for the first time, the user is required
to edit the generated
menu.lst. The user must set the two options
update-grub uses. Then re-run the
update-grub script to update
the
menu.lst file using the default's that have been set.
These are the options passed to the linux kernel:
# kopt=root=/dev/hda1 ro
Everything after "kopt=" is passed to the kernel as parameters. See
bootparam(7) for more information.
This is the grub device from which grub loads the kernel:
# groot=(hd0,1)
(hd0,1) is a partition in grub notation. See
grub(8) for more information.
This option controls if grub should create the alternative boot options in the
menu entries
# alternative=true
# alternative=false
This option controls if grub should lock the alternative boot options see
grub(8) for more information.
# lockalternative=true
# lockalternative=false
This option controls if grub should lock the old kernels.
# lockold=true
# lockold=false
This options controls what is used for the alternative boot options, multiple
altoptions lines are allowed.
# altoptions=(some description) some kernel command line options
# altoptions=(recovery option) single
The description is placed in '()' and the kernel command line options follow
that.
# updatedefault=true
# updatedefault=false
This option controls if grub should update the default entry to keep booting the
same kernel even if a new one is installed.
The
update-grub script can be ran automagically from the
/etc/kernel-img.conf file by adding the following lines:
postinst_hook = update-grub
postrm_hook = update-grub
do_bootloader = no
For further information related to
/etc/kernel-img.conf, see the manpage
kernel-img.conf(5).
grub(8),
grub-install(8),
kernel-img.conf(5) (contained in
the
kernel-package package),
bootparam(7).
The full documentation for
grub is maintained as a Texinfo manual. If the
info and
grub programs are properly installed at your site, the
command
- info grub
should give you access to the complete manual. You may need to install the
grub-legacy-doc package.
This manual page was written by Jason Thomas <
[email protected]>, for the
Debian GNU/Linux system (but may be used by others).