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GRUBBY(8)                   System Manager's Manual                  GRUBBY(8)
NAME
       grubby - command line tool for configuring grub and zipl
SYNOPSIS
       grubby [--add-kernel=kernel-path] [--args=args]
              [--bad-image-okay] [--config-file=path] [--copy-default]
              [--default-kernel] [--default-index] [--default-title]
              [--env=path] [--grub2] [--info=kernel-path]
              [--initrd=initrd-path] [--extra-initrd=initrd-path]
              [--make-default] [--remove-args=args]
              [--remove-kernel=kernel-path] [--set-default=kernel-path]
              [--set-default-index=entry-index] [--title=ntry-title]
              [--update-kernel=kernel-path] [--zipl] [--bls-directory=path]
DESCRIPTION
       grubby  is  a command line tool for updating and displaying information
       about the configuration files for the grub2 and zipl 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 BIOS-based Intel x86 platforms, grub2 is the default bootloader  and
       the  configuration file is in /boot/grub2/grub.cfg. On UEFI-based Intel
       x86 platforms, grub2 is the default bootloader, and  the  configuration
       file is in /boot/efi/EFI/redhat/grub.cfg. On PowerPC platforms, systems
       based on Power8 and Power9 support grub2 as a bootloader and use a con-
       figuration  stored in /boot/grub2/grub.cfg. On s390x platforms the zipl
       bootloader use a default configuration in /etc/zipl.conf.
       All bootloaders define the boot  entries  as  individual  configuration
       fragments  that are stored by default in /boot/loader/entries. The for-
       mat   for   the   config   files   is   specified    at    https://sys-
       temd.io/BOOT_LOADER_SPECIFICATION.   The  grubby tool is used to update
       and display the configuration defined in  the  BootLoaderSpec  fragment
       files.
       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.  Also,
       the title of a boot entry may be specified by using TITLE=title as  the
       argument; all entries with that title are used.
OPTIONS
       --add-kernel=kernel-path
              Add a new boot entry for the kernel located at kernel-path.
       --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  of the default entry 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.
       --bad-image-okay
              When  grubby  is looking for an entry to use for something (such
              as 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.
       --config-file=path
              Use path as the configuration file rather then the default.
       --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.
       --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.
       --env=path
              Use path as the grub2 environment block  file  rather  then  the
              default path.
       --grub2
              Configure grub2 bootloader.
       --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.
       --initrd=initrd-path
              Use initrd-path as the path to an initial ram  disk  for  a  new
              kernel being added.
       --extrainitrd=initrd-path
              Use  initrd-path as the path to an auxiliary init ram disk image
              to be added to the boot entry.
       --make-default
              Make the new kernel entry being added the default entry.
       --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.
       --remove-kernel=kernel-path
              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.
       --set-default=kernel-path
              The  first  entry  which  boots the specified kernel is made the
              default boot entry.
       --set-default-index=entry-index
              Makes the given entry number the default boot entry.
       --title=entry-title
              When a new kernel entry is added  entry-title  is  used  as  the
              title for the entry.
       --update-kernel=kernel-path
              The  entries  for kernels matching kernel-path are updated. Cur-
              rently the only items that can be updated is the kernel argument
              list,  which  is  modified  via  the  --args  and  --remove-args
              options. If the ALL argument is  used  the  variable   GRUB_CMD-
              LINE_LINUX  in /etc/default/grub is updated with the latest ker-
              nel argument list, unless  the  --no-etc-grub-update  option  is
              used.
       --zipl Configure zipl bootloader.
       --bls-directory=path
              Use  path  as  the directory for the BootLoaderSpec config files
              rather than the default /boot/loader/entries.
       --no-etc-grub-update
              Makes grubby to not update the  GRUB_CMDLINE_LINUX  variable  in
              /etc/default/grub  when  the --update-kernel option is used with
              the ALL argument.
SEE ALSO
       zipl(8), mkinitrd(8), kernel-install(8)
AUTHORS
       Erik Troan
       Jeremy Katz
       Peter Jones
       Javier Martinez
                                Wed Apr 29 2020                      GRUBBY(8)