#!/bin/sh

cd /var/db/pkg

function pkg_tree
{
	echo $1 | sed 's/_/  /g'
	typeset P="$(echo $1 | sed 's/_//g')"
	typeset PREFIX="_$(echo $1 | sed 's/[^_]//g')"
	if [ -f $P/+REQUIRING ];
	then
		for PP in $(cat $P/+REQUIRING)
		do
				pkg_tree $PREFIX$PP
		done
	fi
}

if [ "X$1" = "X" ];
then
	for P in *
	do
		if [ ! -f $P/+REQUIRED_BY ];
		then
			pkg_tree $P
		fi
	done
else
	if [ -d "$1" ];
	then
		pkg_tree $1
	else
		echo $0: $1 package not found >&2
		exit 1;
	fi	
fi