Hmmm, I didn't know that and it looks like there are very many on the WWW that don't either as that was where I got my main info from; that means that /dev/random is not POSIX compliant either. Ouch!

I already have this and Shell Check pointed out that RANDOM is undefined that is why I went the direction that I did.

Hmm, awk again, why did I not think of that after all I use it a lot for floating point stuff for CygWin...

You are a star Don thanks, consider my ugly non-compliant code scrubbed I am homing in on your 'awk' example...

This POSIX lark is much more difficult than I expected.

As for your final part about 'awk', if one does not use extensions that are not POSIX compliant then surely that particular 'awk' variant IS still technically conforming to the POSIX _environment_?

---------- Post updated at 11:57 AM ---------- Previous update was at 10:02 AM ----------

As an addendum here I decided to make it look a little clearer for me so I put this into Shell Check...

Code:

#!/bin/sh
awk ' BEGIN \
{	srand()
	while(1)
		printf( "%d %d\n", 16 * rand(), 16 * rand() )
}' | while read -r byteone bytetwo
do
        echo "$byteone $bytetwo"
done

And got this _error_:-

Code:

$ shellcheck myscript
 
Line 2:
awk ' BEGIN \
             ^-- SC1004: You don't break lines with \ in single quotes, it results in literal backslash-linefeed.

$

Do I take it that Shell Check is correct and the backslash is a no-no even inside a completely different language; the above works perfectly for my needs.