#! /bin/sh

function usage {
    local prog=$(basename $0)
    echo "usage: $prog start finish"
    exit 1
}

[ $# -eq 2 ] || usage

start=$1
end=$2

if ! echo -n $start | grep -q '^[0-9]\+$' ||
   ! echo -n $end   | grep -q '^[0-9]\+$'
then
    echo parameters should be integers
    usage
fi
i=$start
while [ $i -le $end ]
do
    echo -n "$i "
    i=$(expr $i + 1)
done
echo
