diff original installed and current files on debian/ubuntu

Edit

apt changed current debian diff difference dpkg installed modified original ubuntu

pv=$(dpkg-query -W -f='${binary:Package}=${Version}' $package)
apt-get download $pv
dpkg-deb -x "${pv//=/_}"_*.deb "/tmp/${pv//=/_}"
find "/tmp/${pv//=/_}/" -type f -printf "%P\n" |
while read f
do
	diff -u "/$f" "/tmp/${pv//=/_}/$f"
done
rm -rf "/tmp/${pv//=/_}"