#!/bin/sh # if [ $# -lt 2 ]; then echo "$0: " exit 1; fi l=$1 h=$2 s=$(expr $h - $l) r=$(head --bytes=2 /dev/urandom | od -l | head -n 1 | sed -e 's/^[^ ]* *//') v=$(expr $r % $s) d=$(expr $l + $v) echo "$0: sleep $d ... start" sleep $d echo "$0: sleep $d ... end"