#!/bin/bash

DIFF=/usr/bin/diff
GREP="/bin/grep"
SED=/bin/sed
DOG=/usr/local/bin/dog
${DIFF} --new-line-format='+%L' --old-line-format='-%L' --unchanged-line-format=' %L' "${1}" "${2}" | ${GREP} -v "^+.*$" | ${GREP} -v "^-.*$" | ${SED} 's/^.//' | ${DOG}