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cat /proc/sys/kernel/random/uuid [I ❤️ Linux] (feddit.org)

submitted 19 hours ago by A_norny_mousse@feddit.org to c/linux@programming.dev

18 comments fedilink hide all child comments

That's all. I just found this in a random script. Generates a random UUID every time it's called. I didn't know.

Of course I can also use uuidgen or pipe /dev/(u)random into something to get a random alphanumeric string - but this is built right into the kernel!

In /proc/sys/kernel/random/, there's also boot_id which seems to do the same, and some tweakable parameters.

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[–] Hamartiogonic@sopuli.xyz 0 points 12 hours ago (2 children)

See also: /dev/null

It’s basically a black hole where you can throw anything.

[–] DaPorkchop_@lemmy.ml 5 points 11 hours ago

Yes, but what if it were a subscription? May I present: /dev/null-as-a-Service.

[–] victorz@lemmy.world 5 points 12 hours ago (4 children)

cat /proc/sys/kernel/random/uuid | /dev/null

[–] DaPorkchop_@lemmy.ml 12 points 11 hours ago (1 children)

Would have to be cat /proc/sys/kernel/random/uuid > /dev/null

You can't pipe to a file, only to programs, and since /dev/null isn't an executable your command will simply give an error.

To make it more clear, consider using dd, which lets you explicitly specify an input and output file. For example: dd if=/proc/sys/kernel/random/uuid of=/dev/sda1 wait shit that wasn't the right output oh god oh fu

[–] sixtoe@lemmy.blahaj.zone 1 points 8 hours ago

i saw this and came to do THE THING but you beat me too it. GOOD ANYA

[–] foenkyfjutschah@programming.dev 3 points 11 hours ago

no.

[–] Hamartiogonic@sopuli.xyz 1 points 9 hours ago (2 children)

That reminds me of the CPU stress test I ran many years ago.

dd if=/dev/random of=/dev/null

If you have 8 cores, just open 8 terminals, and run that code in each of them.

[–] lime@feddit.nu 2 points 8 hours ago* (last edited 8 hours ago)

for i in {1..n}  # where n == number of cores
do
  dd if=/dev/urandom of=/dev/null &
done

# to stop:
jobs -p | xargs kill

[–] YerbaYerba@lemm.ee 2 points 9 hours ago

/dev/urandom should stress the CPU more. /dev/random can be entropy limited

[–] henfredemars@infosec.pub 2 points 11 hours ago (1 children)

The information will be evenly distributed upon its surface and some believe one day it will be be radiated back out into the rest of the system.

[–] Hamartiogonic@sopuli.xyz 2 points 9 hours ago

That's a horrifying concept. Better not think about it.