this post was submitted on 24 May 2025
118 points (97.6% liked)

Linux

7467 readers
376 users here now

A community for everything relating to the GNU/Linux operating system

Also check out:

Original icon base courtesy of [email protected] and The GIMP

founded 2 years ago
MODERATORS
 

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.

❤️🐧

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 16 points 5 days 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

[–] [email protected] 2 points 4 days 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

[–] [email protected] 2 points 5 days ago

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

[–] [email protected] 1 points 4 days 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

[–] [email protected] 1 points 5 days ago* (last edited 5 days ago)

Thanks, I'm overworked lately.

lol, the last part