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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 vari‐
       ous architecture specific bootloaders.  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 bootloader are fully supported.

       Support for yaboot has been deprecated as all ppc architecture hardware since the Power8 uses grub2 or  petit‐
       boot which both use the grub2 configuration 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 architecture for which  grubby  has  been  built.
       Each architecture has a preferred bootloader, and each bootloader has its own configuration file.  If no boot‐
       loader is selected on the command line, grubby will use these default settings to search for an existing  con‐
       figuration.   If  no bootloader configuration file is found, grubby will use the default value for that archi‐
       tecture.  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                  │
       └────────────────┴────────────┴─────────────────────────────────┘


              using --title. Most invocations should also include --initrd with memtest86 as a notable exception.

              The --update-kernel option may not be used in the same invocation.


       --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.  Multi‐
              ple,  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  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 kernels specified by --update-kernel. The
              root argument gets special handling for configuration files that support separate root filesystem  con‐
              figuration.


       --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 architecture.


       --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
       --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. I


       --bootloader-probe
              Attempt to probe for installed bootloaders.  If this option is specified, 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 x86 BIOS platforms.


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


   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 configuration 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  depre‐
              and ppc64le architectures 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,  dep‐
              recated, and unsupported.


       --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 architec‐
              tures.


   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 primar‐
              ily for testing.


       --boot-filesystem=bootfs
              The grub boot loader expects file paths listed in its 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).


       --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 loaders and operating systems.  It  is  sup‐
       ported by the GRUB bootloader.


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


       --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 whitespace 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" --initrd="new_initrd" --copy-default

       Add a new kernel entry with custom arguments

              grubby --add-kernel=new_kernel --title="entry_title" --initrd="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

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)