grubby - Unix, Linux Command

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grubby - command line tool for configuring grub, lilo, and elilo


grubby [--add-kernel=kernel-path] [--args=args]
[--bad-image-okay] [--boot-filesystem=bootfs]
[--bootloader-probe] [--config-file path]
[--copy-default] [--default-kernel]
[--grub] [--lilo] [--yaboot] [--silo] [--zipl]
[--info=kernel-path] [--initrd=initrd-path]
[--make-default] [-o path] [--version]
[--remove-kernel=kernel-path] [--remove-args=args]
[--set-default=kernel-path] [--title=entry-title]
[--add-multiboot=multiboot-path] [--mbargs=args]
[--remove-multiboot=multiboot-path] [--remove-mbargs=args]


grubby is a command line tool for updating and displaying information about the configuration files for the grub, lilo, elilo (ia64), yaboot (powerpc) and zipl (s390) 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.

On Intel x86 platforms, grub is the default bootloader and the configuration file is in /boot/grub/grub.conf. On Intel ia64 platforms, elilo mode is used and the default location for the configuration file is /boot/grub/grub.conf. On PowerPC platforms, yaboot parsing is used and the configuration file should be in /etc/yaboot.conf.

There are a number of ways to specify the kernel used for --info, --remove-kernel, and --update-kernel. Specificying 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 specified by using TITLE=title as the argument; all entries with that title are used.


  Add a new boot entry for the kernel located at kernel-path.

  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 separated 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 handling for specifying the root filesystem (like lilo.conf does).

  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.

  The grub boot loader expects file paths listed in it’s configuration 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 filesystems 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).

  grubby tries to determine if grub or lilo is currently 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 creates). This option is only available on ia32 platforms.

  Use path as the configuration file rather then the 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.

  Display the full path to the current default kernel and exit.

--elilo Use an elilo style configuration file.

--grub Use a grub style configuration file instead of lilo style. This is the default on ia32 platforms.

  Display information on all boot entries which match kernel-path. I

  Use initrd-path as the path to an initial ram disk for a new kernel being added.

--lilo Use a lilo style configuration file.

  Make the new kernel entry being added the default entry.

  The arguments specified by kernel-args are removed from the kernels specified by --update-kernel. The root argument gets special handling for configuration files that support separate root filesystem configuration.

  Removes all boot entries which match kernel-path. This may be used along with --add-kernel, in which case the new kernel being added will never be removed.

  The first entry which boots the specified kernel is made the default boot entry.

  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.

  The entries for kernels matching kernel-path are updated. Currently the only items that can be updated is the kernel argument list, which is modified via the --args and --remove-args options.

  Display the version of grubby being run and then exit immediately.

--yaboot Use an yaboot style configuration file.

--zipl Use an zipl style configuration file.


The Multiboot Specification provides a genreic interface for boot loaders and operating systems. It is supported by the GRUB bootloader.

  Add a new boot entry for the multiboot kernel located at multiboot-path. Note that this is generally accompanied with a --add-kernel option.

  Removes all boot entries which match multiboot-path.

  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.

  The arguments specified by multiboot-args are removed from the kernels specified by --update-kernel.


The command line syntax is more then 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.



Erik Troan <>
Jeremy Katz <>

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