#! /bin/sh

FROM=${1---help}
TO=${2-now}

if [ "$FROM" = "--help" ]; then
	printf "Usage: %s fromdate [todate]\n" "$0" >&2
else
	set -e
	fdt=$(date -d "$FROM" +%s)
	tdt=$(date -d "$TO" +%s)
	echo $(( (tdt - fdt) / 86400 ))
fi