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