#!/bin/sh
#this program calculates the pound of toxic emissions emitted by a typical
#automobile, from the number of trips (cold starts) and miles (averaging for
#traveling at 25 mph and 55 mph) given.  based on an algorithym by patrick
#goebel of global cycling org (velonet).
#peter chen, 1995

MILES=
TRIPS=
PRECISION=
ciao()
{
	echo "usage: $0 -m miles -t trips [-p precision]" >&2
	exit 1
}
while getopts m:t:p: i
do
	case $i in
	m)	MILES=$OPTARG;;
	t)	TRIPS=$OPTARG;;
	p)	PRECISION=".$OPTARG";;
	?)	ciao;;
	esac
done
shift `expr $OPTIND - 1`

[ -z "$MILES" -o -z "$TRIPS" ] && ciao
awk "END{printf\"%${PRECISION}f\n\",($TRIPS*52.84+$MILES*5.955)/454}" /dev/null