grub-probe

Get GRUB filesystem module for a path

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

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

$ sudo grub-probe [[-t|--target]] drive [/dev/sdX] [[-d|--device]]

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

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

$ sudo grub-probe [[-t|--target]] msdos_parttype [/dev/sdX]

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

grub-probe [OPTION...] DEVICE

--help, -h
    display this message and exit

--version, -V
    print version information

--verbose, -v
    print verbose messages

--boot-device
    probe the boot device

--device-map=FILE
    use FILE directly as the device map

-d, --device-map-dev=DIR
    use DIR as the prefix for the device map

--print=PARAMS
    show info for PARAMS (fs,device,uuid,label,partition,dir,ostype)

--target=TARGET
    transform DEVICE map to TARGET map (e.g., 'i386-pc', 'x86_64-efi')

--no-floppy
    do not probe floppy devices

grub-probe is a command-line tool from the GRUB bootloader suite used to inspect devices and filesystems, determining properties like filesystem type, UUID, label, partition details, and more. It is essential for generating accurate GRUB configuration files (grub.cfg), as it allows GRUB scripts to locate kernels, initramfs images, and root filesystems dynamically.

Typically invoked by grub-mkconfig during bootloader updates, it supports probing local filesystems (ext2/3/4, btrfs, xfs, etc.), logical volumes (LVM), MD RAID arrays, encrypted devices (LUKS), and network filesystems. The tool translates device paths using device maps and can output specific parameters in a machine-readable format.

For example, it helps resolve paths like /dev/disk/by-uuid/... or handles multipath setups. It must run with root privileges to access raw devices and may require kernel modules for certain filesystems. Output is plain text by default, making it suitable for scripting.

Requires root privileges; slow on large/complex devices like full disks or RAID; may fail without loaded kernel modules for exotic filesystems; output assumes single-line results.

grub-probe --target=device /boot outputs mapped device (e.g., hd0,msdos1).
grub-probe --print=fs,uuid /dev/sda1 shows filesystem type and UUID.

0 on success, non-zero on probe failure or invalid device.

Introduced in GRUB 2.00 (2012), replacing GRUB Legacy functionality. Developed by the GNU GRUB project since ~2005 to support modern filesystems, LVM, and EFI. Actively maintained for distributions like Ubuntu, Fedora.

grub-mkconfig(8), grub-install(8), grub-mkdevicemap(8), os-prober(8)