#!/bin/bash
# FILE:       	wagon:back/lib/ns/update/rev_ipv4
# DESCRIPTION:	Returns the rDNS reversed version of an IPv4 address
# USAGE:      	rev_ipv4 10.2.0.1
# OUTPUT:     	1.0.2.10.in-addr.arpa
# ERRORS: 
# 	3: Bad usage

[ ${#} -eq 1 ] || exit 3
<<<"${1}" awk -F. '{print $4"."$3"." $2"."$1}' | sed 's/$/.in-addr.arpa/'