#!/bin/sh

lock=/tmp/.beep-lock
test -f $lock && exit 1
touch $lock

head -c 4 /dev/urandom | \
   hexdump -v -e '/1 "%u\n"' |
   awk '{ split("0,3,5,6,7,10,12",a,",");
   for (i = 0; i < 1; i+= 0.00011)
   printf("%08X\n", 40*sin(450*exp((a[$1 % 8]/12)*log(2))*i)) }' |
   xxd -r -p |
   aplay -c 2 -f S16_LE -r 48000 -Dvideocard

rm -f $lock