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

submitted 16 hours ago by [email protected] to c/[email protected]

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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[–] [email protected] 0 points 9 hours ago (2 children)

See also: /dev/null

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

[–] [email protected] 5 points 8 hours ago

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

[–] [email protected] 5 points 9 hours ago (4 children)

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

[–] [email protected] 12 points 8 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

[–] [email protected] 1 points 5 hours ago

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

[–] [email protected] 1 points 6 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.

[–] [email protected] 2 points 5 hours ago* (last edited 5 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

[–] [email protected] 2 points 6 hours ago

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

[–] [email protected] 3 points 8 hours ago

no.

[–] [email protected] 2 points 8 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.

[–] [email protected] 2 points 6 hours ago

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