True Random Dice Roll

tr -cd '1-6' < /dev/urandom | head -c 1; echo
/dev/urandom is cryptographically secure, and indistinguishable from true random, as it gathers data from external sources, influenced by human timing interactions with computers, to fill the entropy pool, and hashes the input with SHA-1. As such, this is a quick way to do a "true random" fair-6 dice roll. Using this method, you could easily create passphrases with Diceware Change the head(1) count to something other than 5 for more or less numbers.

By: atoponce
2012-09-21 02:16:42

1 Alternatives + Submit Alt

What Others Think

Hmmm. Not quite true random. From one byte of randomness mod 6 there are 43 possible 0-3s and only 42 possible 4-5s - therefore your die is weighted against fives and sixes. Perhaps echo $(
unixmonkey40000 · 516 weeks and 1 day ago
You are absolutely right. However, it's biased away from 5 and 6 by 2 percent. So, you could update the command to read more bytes. Reading 2 bytes would produce a bias away from 5 and 6 by 9 thousandths of one percent. Reading 3 bytes would produce a bias away from 5 and 6 of 4 one-hundred thousandths by one percent. I would be willing to bet that standard fabricated dice have a larger bias towards some numbers than that. So, for practical purposes, reading only 10 bytes, would be more than sufficient, and certainly "close enough". I've updated the post.
atoponce · 516 weeks ago
Updated command with a much improved algorithm.
atoponce · 340 weeks and 1 day ago
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paul4422 · 64 weeks and 3 days ago
seofox · 26 weeks and 4 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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