this post was submitted on 24 May 2025
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cat /proc/sys/kernel/random/uuid [I ❤️ Linux] (feddit.org)
submitted 1 day ago* (last edited 19 hours ago) by A_norny_mousse@feddit.org to c/linux@programming.dev
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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~~ is static, and some tweakable parameters.

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[–] DaPorkchop_@lemmy.ml 16 points 1 day ago (4 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

[–] Redjard@lemmy.dbzer0.com 2 points 19 hours ago

dd is just cp but more confusing here.
The only thing dd can do that cp can't is stop ahead of time, which only really matters for infinite files like /dev/random

cp /proc/sys/kernel/random/uuid /dev/sda

[–] A_norny_mousse@feddit.org 1 points 19 hours ago

dd if=/proc/sys/kernel/random/uuid of=/dev/sda1

Peanuts. Real men do dd if=/proc/sys/kernel/random/uuid of=/dev/sda

[–] victorz@lemmy.world 1 points 21 hours ago* (last edited 21 hours ago)

Thanks, I'm overworked lately.

lol, the last part

[–] sixtoe@lemmy.blahaj.zone 2 points 1 day ago

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