#! /bin/bash
usage()
{
echo "$PROG: usage: $PROG [-s seed] lower-limit upper-limit" >&2
}
PROG=${0
SEED=$$
while getopts s: opt
do
case "$opt" in
s) SEED=$OPTARG ;;
*) usage ; exit 2 ;;
esac
done
shift $((OPTIND - 1))
case $ 2) Lower=$1; Upper=$2 ;;
*) usage ; exit 2 ;;
esac
expr "$Lower" + 0 >/dev/null 2>&1 || {
echo "$PROG: lower ($Lower) not an integer" >&2
exit 1
}
expr "$Upper" + 0 >/dev/null 2>&1 || {
echo "$PROG: upper ($Upper) not an integer" >&2
exit 1
}
expr "$SEED" + 0 >/dev/null 2>&1 || {
echo "$PROG: seed ($SEED) not an integer" >&2
exit 1
}
(( $Lower < 0 )) || [ `expr "$Lower" : '.*'` -gt 5 ] && {
echo "$PROG: Lower limit ($Lower) out of range" >&2
exit 1
}
(( $Upper > 32767 )) || [ `expr "$Upper" : '.*'` -gt 5 ] && {
echo "$PROG: Upper limit ($Upper) out of range" >&2;
exit 1
}
(( $SEED < 0 )) || (( $SEED > 32767 )) || [ `expr "$SEED" : '.*'` -gt 5 ] && {
echo "$PROG: Seed value ($SEED) out of range (0 to 32767)" >&2
exit 1
}
(( $Upper <= $Lower )) && {
echo "$PROG: upper ($Upper) <= lower value ($Lower)" >&2
exit 1
}
RANDOM=$SEED
let rand="$RANDOM % ($Upper - $Lower + 1) + $Lower"
echo $rand