Ubuntu Manpage: bootctl - Control EFI firmware boot settings and manage boot loader

Provided by: systemd_249.11-0ubuntu3.12_amd64

NAME

       bootctl - Control EFI firmware boot settings and manage boot loader

SYNOPSIS

       bootctl [OPTIONS...] {COMMAND}

DESCRIPTION

       bootctl can check the EFI firmware and boot loader status, list and manage available boot
       loaders and boot loader entries, and install, update, or remove the systemd-boot(7) boot
       loader on the current system.

GENERIC EFI FIRMWARE/BOOT LOADER COMMANDS

       These commands are available on any EFI system, regardless of the boot loader used.

       status
           Shows brief information about the system firmware, the boot loader that was used to
           boot the system, the boot loaders currently available in the ESP, the boot loaders
           listed in the firmware's list of boot loaders and the current default boot loader
           entry. If no command is specified, this is the implied default.

       reboot-to-firmware [BOOL]
           Query or set the "Reboot-Into-Firmware-Setup" flag of the EFI firmware. Takes a
           boolean argument which controls whether to show the firmware setup on next system
           reboot. If the argument is omitted shows the current status of the flag, or whether
           the flag is supported. This controls the same flag as systemctl reboot
           --firmware-setup, but is more low-level and allows setting the flag independently from
           actually requesting a reboot.

       systemd-efi-options [STRING]
           When called without the optional argument, prints the current value of the
           "SystemdOptions" EFI variable. When called with an argument, sets the variable to that
           value. See systemd(1) for the meaning of that variable.

BOOT LOADER SPECIFICATION COMMANDS

These commands are available for all boot loaders that implement the Boot Loader
Specification[1] and/or the Boot Loader Interface[2], such as systemd-boot.

list
Shows all available boot loader entries implementing the Boot Loader Specification[1],
as well as any other entries discovered or automatically generated by a boot loader
implementing the Boot Loader Interface[2].

set-default ID, set-oneshot ID
Sets the default boot loader entry. Takes a single boot loader entry ID string as
argument. The set-oneshot command will set the default entry only for the next boot,
the set-default will set it persistently for all future boots. Optionally, the boot
loader entry ID may be specified as one of: @default, @oneshot or @current, which
correspond to the current default boot loader entry for all future boots, the current
default boot loader entry for the next boot, and the currently booted boot loader
entry. These special IDs are resolved to the current values of the EFI variables
LoaderEntryDefault, LoaderEntryOneShot and LoaderEntrySelected, see Boot Loader
Specification[1] for details. These special IDs are primarily useful as a quick way to
persistently make the currently booted boot loader entry the default choice, or to
upgrade the default boot loader entry for the next boot to the default boot loader
entry for all future boots, but may be used for other operations too. When an empty
string ("") is specified as an ID, then the corresponding EFI variable will be unset.

SYSTEMD-BOOT COMMANDS

These commands manage the systemd-boot EFI boot loader, and do not work in conjunction
with other boot loaders.

install
Installs systemd-boot into the EFI system partition. A copy of systemd-boot will be
stored as the EFI default/fallback loader at ESP/EFI/BOOT/BOOT*.EFI. The boot loader
is then added to the top of the firmware's boot loader list.

update
Updates all installed versions of systemd-boot(7), if the available version is newer
than the version installed in the EFI system partition. This also includes the EFI
default/fallback loader at ESP/EFI/BOOT/BOOT*.EFI. The boot loader is then added to
end of the firmware's boot loader list if missing.

remove
Removes all installed versions of systemd-boot from the EFI system partition and the
firmware's boot loader list.

is-installed
Checks whether systemd-boot is installed in the ESP. Note that a single ESP might host
multiple boot loaders; this hence checks whether systemd-boot is one (of possibly
many) installed boot loaders — and neither whether it is the default nor whether it is
registered in any EFI variables.

random-seed
Generates a random seed and stores it in the EFI System Partition, for use by the
systemd-boot boot loader. Also, generates a random 'system token' and stores it
persistently as an EFI variable, if one has not been set before. If the boot loader
finds the random seed in the ESP and the system token in the EFI variable it will
derive a random seed to pass to the OS and a new seed to store in the ESP from the
combination of both. The random seed passed to the OS is credited to the kernel's
entropy pool by the system manager during early boot, and permits userspace to boot up
with an entropy pool fully initialized very early on. Also see systemd-boot-system-
token.service(8).

See Random Seeds[3] for further information.

OPTIONS

The following options are understood:

--esp-path=
Path to the EFI System Partition (ESP). If not specified, /efi/, /boot/, and
/boot/efi/ are checked in turn. It is recommended to mount the ESP to /efi/, if
possible.

--boot-path=
Path to the Extended Boot Loader partition, as defined in the Boot Loader
Specification[1]. If not specified, /boot/ is checked. It is recommended to mount the
Extended Boot Loader partition to /boot/, if possible.

-p, --print-esp-path
This option modifies the behaviour of status. Only prints the path to the EFI System
Partition (ESP) to standard output and exits.

-x, --print-boot-path
This option modifies the behaviour of status. Only prints the path to the Extended
Boot Loader partition if it exists, and the path to the ESP otherwise to standard
output and exit. This command is useful to determine where to place boot loader
entries, as they are preferably placed in the Extended Boot Loader partition if it
exists and in the ESP otherwise.

Boot Loader Specification Type #1 entries should generally be placed in the directory
"$(bootctl -x)/loader/entries/". Existence of that directory may also be used as
indication that boot loader entry support is available on the system. Similarly, Boot
Loader Specification Type #2 entries should be placed in the directory "$(bootctl
-x)/EFI/Linux/".

Note that this option (similar to the --print-booth-path option mentioned above), is
available independently from the boot loader used, i.e. also without systemd-boot
being installed.

--no-variables
Do not touch the firmware's boot loader list stored in EFI variables.

--graceful
Ignore failure when the EFI System Partition cannot be found, or when EFI variables
cannot be written. Currently only applies to random seed operations.

--make-machine-id-directory=yes|no|auto
Control creation and deletion of the top-level machine ID directory on the file system
containing boot loader entries (i.e. beneath the file system returned by the
--print-boot-path option, see above) during install and remove, respectively. "auto"
is equivalent to "yes" if /etc/machine-id resides on a filesystem other than tmpfs and
"no" otherwise (in the latter case the machine ID is likely transient and hence should
not be used persistently in the ESP). Defaults to "auto". See machine-id(5) for
details about the machine ID concept and file.

Overriding this may be desirable to hide the machine ID from the (unencrypted) ESP,
configure a kernel-install(8) script, or, conversely, commit a transient machine ID.

The top-level machine ID directory is useful to allow smooth multi-boot installations:
each installed OS instance will have a different machine ID and thus a separate
directory to place its boot-time resources in. If this feature is turned off with this
option, care needs to be taken that multiple OS instances do not place conflicting
files on the shared ESP and Extended Boot Loader Partitions, or that multiple OS
instances are not possible.

--no-pager
Do not pipe output into a pager.

-h, --help
Print a short help text and exit.

--version
Print a short version string and exit.

EXIT STATUS

       On success, 0 is returned, a non-zero failure code otherwise.

ENVIRONMENT

       If $SYSTEMD_RELAX_ESP_CHECKS=1 is set the validation checks for the ESP are relaxed, and
       the path specified with --esp-path= may refer to any kind of file system on any kind of
       partition.

       Similarly, $SYSTEMD_RELAX_XBOOTLDR_CHECKS=1 turns off some validation checks for the
       Extended Boot Loader partition.

NOTES

        1. Boot Loader Specification
           https://systemd.io/BOOT_LOADER_SPECIFICATION

        2. Boot Loader Interface
           https://systemd.io/BOOT_LOADER_INTERFACE

        3. Random Seeds
           https://systemd.io/RANDOM_SEEDS