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.

❤️🐧

  • timhh@programming.dev
    92·
    19 hours ago

    Yeah but please don’t actually use this. Use a proper UUID library that works cross-platform and lets you choose the UUID type and can be seeded etc.

    • A_norny_mousse@feddit.orgOP
      2·
      4 hours ago

      Can you explain?
      Use for what?
      Also it is being seeded, according to the file urandom_min_reseed_secs which is also writeable. Here are the other files:

      -r--r--r-- 1 root root 0 25. 5. 11:13 boot_id
-r--r--r-- 1 root root 0 25. 5. 11:19 entropy_avail
-r--r--r-- 1 root root 0 25. 5. 11:19 poolsize
-rw-r--r-- 1 root root 0 25. 5. 11:19 urandom_min_reseed_secs
-r--r--r-- 1 root root 0 25. 5. 11:19 uuid
-rw-r--r-- 1 root root 0 25. 5. 11:19 write_wakeup_threshold

      edit: the type is always DCE/random