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.

❤️🐧

  • Victor
    9•15 days ago
    cat /proc/sys/kernel/random/uuid > /dev/null
    • @DaPorkchop_@lemmy.ml
      16•15 days ago

      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
        2•15 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

      • Victor
        1•15 days ago

        Thanks, I’m overworked lately.

        lol, the last part

    • @henfredemars@infosec.pubEnglish
      3•15 days ago

      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.xyzEnglish
      1•15 days ago

      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!English
        3•15 days 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
          • lime!English
            1•15 days ago

            the advantage of yours is that you can actually see the performance number afterwards.

      • Victor
        2•15 days ago

        Can you guarantee that each process will run on its own core?

        • @Hamartiogonic@sopuli.xyz
          2•15 days ago

          Absolutely not, quite the opposite actually. However, the end result is close to 100% CPU load, which is good enough for some purposes. Let’s say you want to test the performance of your CPU cooler, or overclock stability, this should good enough. There are also dedicated tools for people with more advanced needs.