Improvise a Hardware Random-Number Generator
Shell
Reads a single sample from the microphone stream and prints its least-significant bit, which should be dominated by noise.
EDIT: Changed to unmute the microphone ... and everything else too!
# Warning - unmutes EVERYTHING!
for DEV in `amixer | grep Simple | sed -e &quot;s/.*'\(.*\)'.*/\\1/&quot; -e &quot;s/ /~/g&quot;`
do
    amixer -q -- sset &quot;`echo $DEV | sed 's/~/ /g'`&quot; unmute 100% 2&gt;/dev/null
done

echo $(( `od -N1 -d &lt; /dev/dsp | head -n1 | sed 's/.* //'` &amp; 1 ))