GRUBBY(8) System Manager's Manual GRUBBY(8)
NAME
grubby - command line tool used to configure bootloader menu entries
across multiple architectures
SYNOPSIS
grubby [OPTIONS]
DESCRIPTION
General Information
grubby is a command line tool for updating and displaying information
about the configuration files for various architecture specific boot-
loaders. It is primarily designed to be used from scripts which
install new kernels and need to find information about the current boot
environment.
Architecture Support
The grubby executable has full support for the grub2 bootloader on
x86_64 systems using legacy BIOS or modern UEFI firmware and ppc64 and
ppc64le hardware using OPAL or SLOF as firmware.
Legacy s390 and the current s390x architectures and their zipl boot-
loader are fully supported.
Support for yaboot has been deprecated as all ppc architecture hardware
since the Power8 uses grub2 or petitboot which both use the grub2 con-
figuration file format.
Legacy bootloaders LILO, SILO, and ELILO are deprecated and no longer
receiving active support in favor of previously mentioned bootloaders.
Default Behavior
The default bootloader target is primarily determined by the architec-
ture for which grubby has been built. Each architecture has a pre-
ferred bootloader, and each bootloader has its own configuration file.
If no bootloader is selected on the command line, grubby will use these
default settings to search for an existing configuration. If no boot-
loader configuration file is found, grubby will use the default value
for that architecture. These defaults are listed in the table below.
+----------------+------------+---------------------------------+
| Arch | Bootloader | Configuration File |
+----------------+------------+---------------------------------+
| x86_64 [BIOS] | grub2 | /boot/grub2/grub.cfg |
+----------------+------------+---------------------------------+
| x86_64 [UEFI] | grub2 | /boot/efi/EFI/redhat/grub.cfg |
+----------------+------------+---------------------------------+
| i386 | grub2 | /boot/grub2/grub.cfg |
+----------------+------------+---------------------------------+
| ia64 | elilo | /boot/efi/EFI/redhat/elilo.conf |
+----------------+------------+---------------------------------+
| ppc [>=Power8] | grub2 | /boot/grub2/grub.cfg |
+----------------+------------+---------------------------------+
| ppc [<=Power7] | yaboot | /etc/yaboot.conf |
+----------------+------------+---------------------------------+
| s390 | zipl | /etc/zipl.conf |
+----------------+------------+---------------------------------+
| s390x | zipl | /etc/zipl.conf |
+----------------+------------+---------------------------------+
Special Arguments
There are a number of ways to specify the kernel used for --info,
--remove-kernel, and --update-kernel. Specifying DEFAULT or ALL selects
the default entry and all of the entries, respectively. If a comma
separated list of numbers is given, the boot entries indexed by those
numbers are selected. Finally, the title of a boot entry may be speci-
fied by using TITLE=title as the argument; all entries with that title
are used.
OPTIONS
Basic Options
--add-kernel=kernel-path
Add a new boot entry for the kernel located at kernel-path. A
title for the boot entry must be set using --title. Most invoca-
tions should also include --initrd with memtest86 as a notable
exception.
The --update-kernel option may not be used in the same invoca-
tion.
--remove-kernel=kernel-path
Remove all boot entries which match kernel-path. This may be
used along with --add-kernel, in which case the new entry being
added will not be removed.
--update-kernel=kernel-path
Update the entries for kernels matching kernel-path. Currently
the only item that can be updated is the kernel argument list,
which is modified via the --args and --remove-args options.
--args=kernel-args
When a new kernel is added, this specifies the command line
arguments which should be passed to the kernel by default (note
they are merged with the arguments from the template if --copy-
default is used). When --update-kernel is used, this specifies
new arguments to add to the argument list. Multiple, space sepa-
rated arguments may be used. If an argument already exists the
new value replaces the old values. The root= kernel argument
gets special handling if the configuration file has special han-
dling for specifying the root filesystem (like lilo.conf does).
--remove-args=kernel-args
The arguments specified by kernel-args are removed from the ker-
nels specified by --update-kernel. The root argument gets spe-
cial handling for configuration files that support separate root
filesystem configuration.
--copy-default
grubby will copy as much information (such as kernel arguments
and root device) as possible from the current default kernel.
The kernel path and initrd path will never be copied.
--title=entry-title
When a new kernel entry is added entry-title is used as the
title (lilo label) for the entry. If entry-title is longer then
maximum length allowed by the bootloader (15 for lilo, unlimited
for grub and elilo) the title is shortened to a (unique) entry.
--initrd=initrd-path
Use initrd-path as the path to an initial ram disk for a new
kernel being added.
--efi Use appropriate bootloader commands for EFI on this architec-
ture.
--set-default=kernel-path
The first entry which boots the specified kernel is made the
default boot entry. This may not be invoked with --set-default-
index.
--set-default-index=entry-index
Makes the given entry number the default boot entry. This may
not be invoked with --set-default. The given value represents
the index in the post-modification boot entry list.
--make-default
Make the new kernel entry being added the default entry.
--set-index=entry-index
Set the position at which to add a new entry created with --add-
kernel.
--debug
Display extra debugging information for failures.
-i, --extra-initrd=initrd-path
Use initrd-path as the path for an auxiliary initrd image.
Display Options
Passing the display option to grubby will cause it to print out the
requested information about the current bootloader configuration and
then immediately exit. These options should not be used in any script
intended to update the bootloader configuration.
--default-kernel
Display the full path to the current default kernel and exit.
--default-index
Display the numeric index of the current default boot entry and
exit.
--default-title
Display the title of the current default boot entry and exit.
--info=kernel-path
Display information on all boot entries which match kernel-path.
If kernel-path is DEFAULT, then information on the default ker-
nel is displayed. If kernel-path is ALL, then information on all
boot entries are displayed.
--bootloader-probe
Attempt to probe for installed bootloaders. If this option is
specified, grubby tries to determine if grub or lilo is cur-
rently installed. When one of those bootloaders is found the
name of that bootloader is displayed on stdout. Both could be
installed (on different devices), and grubby will print out the
names of both bootloaders, one per line. The probe for grub
requires a commented out boot directive grub.conf identical to
the standard directive in the lilo configuration file. If this
is not present grubby will assume grub is not installed (note
that anaconda places this directive in grub.conf files it cre-
ates).
This option is only available on x86 BIOS platforms.
-v, --version
Display the version of grubby being run and then exit immedi-
ately.
Output Format Options
Sane default options for the current platform are compiled into grubby
on a per platform basis. These defaults determine the format and layout
of the generated bootloader configuration file. A different configura-
tion file format may be specified on the command line if the system
uses a supported alternative bootloader.
--elilo
Use an elilo style configuration file. This is the default on
ia64 platforms. This format is deprecated.
--extlinux
Use an extlinux style configuration file. This format is depre-
cated.
--grub Use a grub style configuration file. This is the default on the
i386 architecture.
--grub2
Use a grub2 style configuration file. This is the default on
x86_64 architecture as well as the ppc64 and ppc64le architec-
tures running on Power8 or later hardware.
--lilo Use a lilo style configuration file.
--silo Use a silo style configuration file. This is the default on
SPARC systems. This format is legacy, deprecated, and unsup-
ported.
--yaboot
Use a yaboot style configuration file. This is the default for
the ppc architecture on on Power7 and earlier hardware.
--zipl Use a zipl style configuration file. This is the default on the
legacy s390 and current s390x architectures.
Override Options
--bad-image-okay
When grubby is looking for a entry to use for something (such as
a template or a default boot entry) it uses sanity checks, such
as ensuring that the kernel exists in the filesystem, to make
sure entries that obviously won't work aren't selected. This
option overrides that behavior, and is designed primarily for
testing.
--boot-filesystem=bootfs
The grub boot loader expects file paths listed in its configura-
tion path to be relative to the top of the filesystem they are
on, rather then relative to the current root filesystem. By
default grubby searches the list of currently mounted filesys-
tems to determine this. If this option is given grubby acts as
if the specified filesystem was the filesystem containing the
kernel (this option is designed primarily for testing).
--env=path
Path for the file where grub environment data is stored.
-c, --config-file=path
Use path as the configuration file rather then the default.
-o, --output-file=file_path
The destination path for the updated configuration file. Use "-"
to send it to stdout.
Multiboot Options
The Multiboot Specification provides a generic interface for boot load-
ers and operating systems. It is supported by the GRUB bootloader.
--add-multiboot=multiboot-path
Add a new boot entry for the multiboot kernel located at multi-
boot-path. Note that this is generally accompanied with a
--add-kernel option.
--remove-multiboot=multiboot-path
Removes all boot entries which match multiboot-path.
--mbargs=multiboot-args
When a new multiboot kernel is added, this specifies the command
line arguments which should be passed to that kernel by default
When --update-kernel is used, this specifies new arguments to
add to the argument list. Multiple, space separated arguments
may be used. If an argument already exists the new value
replaces the old values.
--remove-mbargs=multiboot-args
The arguments specified by multiboot-args are removed from the
kernels specified by --update-kernel.
BUGS
The command line syntax is more than a little baroque. This probably
won't be fixed as grubby is only intended to be called from shell
scripts which can get it right.
EXAMPLE
The following examples assume the following:
+----------------+---------------------------------------------+
| cfg_file | Full path to bootloader config file |
+----------------+---------------------------------------------+
| new_kernel | Full path to kernel image to be installed |
+----------------+---------------------------------------------+
| old_kernel | Full path to old kernel image to be removed |
+----------------+---------------------------------------------+
| current_kernel | Full path to a currently installed kernel |
+----------------+---------------------------------------------+
| entry_title | Title that appears on bootloader menu |
+----------------+---------------------------------------------+
| new_initrd | Full path to initrd for a new kernel |
+----------------+---------------------------------------------+
| kernel_args | Set of arguments for the kernel |
+----------------+---------------------------------------------+
| menu_index | Index number of a menu entry |
+----------------+---------------------------------------------+
The examples below quote strings that may have spaces or other white-
space in them. It is also perfectly valid to backslash escape these
strings if that is more convenient.
Add a new kernel entry and copy all options from the current default
kernel. This is the behavior that most users will want.
grubby --add-kernel=new_kernel --title="entry_title" --ini-
trd="new_initrd" --copy-default
Add a new kernel entry with custom arguments
grubby --add-kernel=new_kernel --title="entry_title" --ini-
trd="new_initrd" --args=kernel_args
Remove all menu entries for a specified kernel.
grubby --remove-kernel=old_kernel
Target a single menu entry to remove without targetting other entries
with the same kernel.
grubby --info=old_kernel
grubby --remove-kernel=menu_index
Update the arguments for all entries of a specific kernel. New argu-
ments get added while existing arguments get updated values.
grubby --update-kernel=current_kernel --args="kernel_args"
Remove the arguments for a single entry of a specific kernel.
grubby --info=current_kernel
grubby --remove-args=menu_index --args="kernel_args"
SEE ALSO
grub(8), lilo(8), yaboot(8), zipl(8), dracut(8), mkinitrd(8)
AUTHORS
Erik Troan
Jeremy Katz
Peter Jones
Robert Marshall
Tue Jan 18 2005 GRUBBY(8)
Linux-Distributionen
Huschi als Linux-Admin