script/random-sleep.sh

   1 #!/bin/sh
   2 #
   3
   4 if [ $# -lt 2 ]; then
   5         echo "$0: <low> <high>"
   6         exit 1;
   7 fi
   8
   9 l=$1
  10 h=$2
  11
  12 s=$(expr $h - $l)
  13
  14 r=$(head --bytes=2 /dev/urandom | od -l | head -n 1 | sed -e 's/^[^ ]*  *//')
  15
  16 v=$(expr $r % $s)
  17 d=$(expr $l + $v)
  18
  19 echo "$0: sleep $d ... start"
  20 sleep $d
  21 echo "$0: sleep $d ... end"