How can I randomize a number with 32 hexadecimal digits?

Question

I am trying to randomize a number with 32 hexadecimal digits in bash with seed which depends on the date.
I thought about something like: RANDOM=$(date +%N | cut -b4-9) , but it's not give me 32 hexadecimal digits.

ideas?

`date +%N | md5sum | cut -c1-32`, though its randomness is debatable. — M. Nejat Aydin, Nov 28 '22 at 17:39
@M.NejatAydin what is the purpose of `md5sum` in your command? — Software_t, Nov 28 '22 at 17:40
@Software_t md5sum is a 128-bit hash, thus 32 hexadecimal digits. — M. Nejat Aydin, Nov 28 '22 at 17:42
@M.NejatAydin Are you tried it? i don't get it as 32 hexadecimal digits .. — Software_t, Nov 28 '22 at 18:20
`RANDOM` is an OS variable that generates a somewhat-random 16-bit number ... nowhere near enough to generate a 32-digit hex value — markp-fuso, Nov 28 '22 at 18:24
why the requirement to use a date (nanoseconds) as a seed? are you actually going to save the `date +%N` output for later use (eg, to reseed `RANDOM`)? — markp-fuso, Nov 28 '22 at 18:31
Does this answer your question? [How to get a random string of 32 hexadecimal digits through command line?](https://stackoverflow.com/questions/34328759) or [Shell script to generate random hex numbers](https://stackoverflow.com/q/40277918) — markp-fuso, Nov 28 '22 at 18:35
@Software_t Sure, I've tried it. You must certainly get a 32-xdigit number (tough its randomness is debatable). — M. Nejat Aydin, Nov 28 '22 at 18:47
Why are you specifically using date as seed? Is that *necessary*? It's seed only, so isn't it better to just assure you have sufficiently random data? — Paul Hodges, Nov 28 '22 at 19:20
Attempting to override the built-in variable `RANDOM` is separately an error. You won't get back the value you assigned. Perhaps see also [Correct Bash and shell script variable capitalization](https://stackoverflow.com/questions/673055/correct-bash-and-shell-script-variable-capitalization) — tripleee, Nov 29 '22 at 07:23

score 0 · Answer 1 · answered Nov 28 '22 at 17:32

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I'm always generating with: openssl rand -base64 32

answered Nov 28 '22 at 17:32

Ruslan Issayev

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2

i asked random with date – Software_t Nov 28 '22 at 19:04

markp-fuso · Answer 2 · 2022-11-28T18:49:14.470

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Feed /dev/urandom to tr and delete all but hex digits:

$ tr -dc '[:xdigit:]' < /dev/urandom | head -c32
90D75De9CaA0C38a15B8facf59CBBDdc

If you need all upper (or all lower):

$ tr -dc '0-9A-F' < /dev/urandom | head -c32
CBABC737B0F9C059531CA7672FCA52F6

$ tr -dc '0-9a-f' < /dev/urandom | head -c32
87fa3f2e4f98a8e8eecb8236e2736eba

edited Nov 28 '22 at 18:49

answered Nov 28 '22 at 18:37

markp-fuso

28,790
4
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but i aksed for random number according to seed that related to date – Software_t Nov 28 '22 at 19:05

score 0 · Answer 3 · answered Nov 28 '22 at 22:31

Eliminate your need for the date.
If it's an assignment, say so.

Assuming it is -

$: src="0123456789ABCDEF" && RANDOM=$(( $(date +%s) % 32767 ))    &&
>  for c in {1..32}; do printf "%s" ${src:$((RANDOM%16)):1}; done &&
>  echo 
14E4552562D03BB6FCAC8602B0D38BE7

How can I randomize a number with 32 hexadecimal digits?

3 Answers3