grub-probe

probe device and filesystem information for GRUB

TLDR

Name the filesystem module GRUB needs for a path

$ sudo grub-probe --target fs [/boot]

Name the device that holds a path

$ sudo grub-probe --target device [/boot]

Translate a system device into GRUB's own drive name

$ sudo grub-probe --device --target drive [/dev/sda1]

Read the filesystem UUID

$ sudo grub-probe --target fs_uuid [/boot]

Read the filesystem label

$ sudo grub-probe --target fs_label [/boot]

Report the partition table type

$ sudo grub-probe --target partmap [/boot]

Report the MBR partition type byte

$ sudo grub-probe --device --target msdos_parttype [/dev/sda1]

Report abstractions such as LVM or RAID in the path

$ sudo grub-probe --target abstraction [/boot]

Report the UUID of an encrypted container

$ sudo grub-probe --target cryptodisk_uuid [/boot]

Emit the hint strings used in generated GRUB config

$ sudo grub-probe --target hints_string [/boot]

Probe through a custom device map

$ sudo grub-probe --device-map [path/to/device.map] --target drive [/boot]

Show what it is doing while probing

$ sudo grub-probe --verbose --target fs [/boot]

SYNOPSIS

grub-probe [options] -t target path|device

grub-probe extracts device and filesystem information in GRUB's naming format. It is primarily used internally by GRUB tools but is useful for debugging boot configuration.Target types include fs (filesystem module), device (system device path), disk (system disk path), drive (GRUB drive name like hd0), fs_uuid (filesystem UUID), fs_label (filesystem label), partmap (partition map type), partuuid (partition UUID), abstraction (abstraction module like lvm), cryptodisk_uuid, msdos_parttype, gpt_parttype, and various boot hint targets.This tool bridges Linux device names to GRUB's naming conventions, which is essential for generating correct boot configurations.

PARAMETERS

-t, --target TARGET

Information to probe: fs, fsuuid, fslabel, device, disk, drive, partmap, partuuid, abstraction, cryptodiskuuid, msdosparttype, gptparttype, hintsstring, zero_check (default: fs)

-d, --device

Treat argument as a system device, not a path

-m, --device-map FILE

Use custom device map file (default: /boot/grub/device.map)

-0

Separate items in output using ASCII NUL characters

-v, --verbose

Enable verbose output (pass twice for debug printing)

INSTALL

sudo apt install grub-common

sudo pacman -S grub

sudo apk add grub

CAVEATS

Requires root privileges for most operations. Device mapping can change between boots, especially with removable media. GRUB drive naming may differ from Linux device names.

HISTORY

grub-probe is part of GRUB 2's toolset, providing the device detection logic used by grub-install and grub-mkconfig. It replaced simpler detection methods used in GRUB Legacy.