Grub2 prompt command syntax

English Install/Boot/Login
1

Hello

Question 1

Where I can find the syntax of any command available at grub prompt.

Question 2

When in grub prompt session because boot failed, how to get the current uuid of any partition (hdx,gtpy).
It seems that opensuse does not support

probe --fs-uuid (hd0,gpt6)
probe --fs-uuid hd0,gpt6
probe --fs-uuid /dev/sda6

From gnu.org :

16.3.58 probe
probe ‘–set’ var]
[Command]
‘–driver’|‘–partmap’|‘–fs’|‘–fs-uuid’|‘–label’|‘–part-uuid’
device
Retrieve device information. If option ‘–set’ is given, assign result to variable var,
otherwise print information on the screen.
The option ‘–part-uuid’ is currently only implemented for MSDOS and GPT for-
matted disks.

Any help is welcome

2

If it is not in GRUB manual, you have to look in source code. Usually commands print at least basic help that shows usage and syntax.

When in grub prompt session because boot failed, how to get the current uuid of any partition (hdx,gtpy).
It seems that opensuse does not support

Most GRUB functionality is implemented by external modules that are loaded on demand. The binary directly loaded by firmware usually includes only the bare minimum needed to access partition where all other GRUB modules are located. If this partition was not found, then you obviously cannot use any command implemented by modules from this partition. You did not explain what “boot failed” means nor show any errors from failed boot so we have no way to guess whether this is what you are experiencing.

3

Hello.
Thank you for your answer.

From gnu.org :

16.3.58 probe
probe ‘–set’ var]
[Command]
‘–driver’|‘–partmap’|‘–fs’|‘–fs-uuid’|‘–label’|‘–part-uuid’
device
Retrieve device information. If option ‘–set’ is given, assign result to variable var,
otherwise print information on the screen.
The option ‘–part-uuid’ is currently only implemented for MSDOS and GPT for-
matted disks.

I have not found a way to print command help from grub prompt.

How to guess the where and how ?

I cannot give more explanation than “boot failed” see following picture :
https://paste.opensuse.org/96890994

My guess is that it is relative to partition uuid.

1°) i would like to read the uuid of any partition to check if they are those expected ( from my own documentation ).
2°) if yes, check if (hdx,gpty)/efi/opensuse/grub.cfg have the expected uuid
3°) if 2°) false then edit (hdx,gpty)/efi/opensuse/grub.cfg ( by using the install cd in rescue mode to access (hdx,gpty))

Any help is welcome

4

That is different case. You are on EFI and by default openSUSE installs signed grub image to support Secure Boot. This signed image has module loading disabled so you are limited to the commands included during build. Unfortunately, neither full ls nor probe are there.

5

Ok.
I try another way but get other problem.

You can look at my new thread :
https://forums.opensuse.org/showthread.php/569224-grub2-probe-error-failed-to-get-canonical-path-of-tmpfs

Anyway thank you for helping.