So I found the source of the problem that I posted about yesterday here. The problem is I get the following error when I run the following command with sudo (although the command runs fine without sudo):
After some further digging on my system I traced the issue to the following files in /dev. When I set the permissions of the files to 777 I have no problem running the above command as sudo, this is the ls -l output of the files as they are on a fresh boot:
I'm hoping somebody here can shed some light on whats happening here and why the command cannot access those files. Given it's being run with sudo that should mean the command should be able to access any files it wants regardless of permissions right? The only possible situation I can imagine would be the command (when run as root and not a regular user) tries to access that file as another user, how would I find out which user this is so I can add them to the video group? The only thing I can find in /etc/passwd that might be a relevent user is the nvpd user which is already in the video group:
How should I proceed from here? I assume anybody within the video group should be able to access the files fine, so how can I figure out who is trying to access the files so I can add them to the video group? Unless there is actually something wrong with root and root can't access those files for some reason?

EDIT:
Found the config file for the command I am running and heres it's contents, I assume I should change the "user" setting to something else but what? It seems like it should be working the way it currently is:

I also tried setting user to "root:root" but that didn't work either.

probably this: https://github.com/NVIDIA/nvidia-docker/issues/1547

Have you tried adding your user to the videos group?
The command 'groups' will tell you what croups your user already belongs to.
If not already in the videos group then the command below will add your user to that group
sudo usermod -a -G videos yourusername
You will have to log out and back in for the change to take affect.

Yes:

Thank you, I did notice that in my searches, if you have a look at my edit I said I tried that, sadly it didn't seem to do anything as far as I could tell.

And cumputersavvy I am apart of the video group, if you look in the output I posted that my username is in the video group, along with root, boinc, greetd and nvpd.

What you posted is not the output of the groups command, but instead a line out of the /etc/group file, so it was not completely clear that your user was in that group (especially since you had not stated your username and we had no way to know your username here is the same as the username on your PC.)

If the program runs properly as your regular user, then why would you need to use sudo or run it as the root user? The linux/unix policy is to run everything with the least permissions possible so if root is not needed then you really should not use it.

In fact there are several programs (and more all the time) that check and will not run if started as root (uid=0).

Yeah fair enough I probably should have done it using the groups command, that would have made it clearer, I'm sorry.

The reason I need to be able use it with sudo is because LXD is root and uses the same utilities, and when LXD tries to use these utilities since it's root they don't work, I was told this by the lead LXD dev here.

Most of the time programs need to presume that, when they attempt to open a file, they may or may not succeed in doing so for any number of reasons. They need to be prepared to gracefully handle that possibility, and inform the user as required.