Re: [ILUG] Random number?

From: kevin lyda (kevin at domain suberic.net)
Date: Sun 25 Feb 2001 - 21:40:17 GMT


On Sun, Feb 25, 2001 at 10:03:16PM +0000, Sean O'Riordain wrote:
> under more recent kernels >2.2? there is an entropy pool which is taken
> from things like disk activity etc... which is designed to be pretty
> random... openssl will have routines to use it... no idea how to use it
> in a shell script though...

actually, 1.3.30 according to the random(4) man page.

very random:
#!/bin/sh
RANDOM=`dd if=/dev/random bs=1 count=2 2>/dev/null \
        | od -tu2 \
        | head -1 \
        | awk '{print $2}'`
echo $RANDOM

pretty random:
#!/bin/sh
RANDOM=`dd if=/dev/urandom bs=1 count=2 2>/dev/null \
        | od -tu2 \
        | head -1 \
        | awk '{print $2}'`
echo $RANDOM

it's also a one liner in perl, but that's cheating... the former
will hang till entropy is deemed large enough, the latter will
do the best it can and quickly.

kevin

-- 
kevin at domain suberic.net        i...  i have a dream.  and that dream is:
fork()'ed on 37058400    use DIY::Tiler;
meatspace place: orbit   my($t) = new DIY::Tiler;
                         $t->tile(-room => "en-suite", -style => "stone");


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