Debian package-watch

#!/bin/bashif [ -z "$4" ]; then    printf "Usage: %s package distro arch mail\n" `basename $0`;    exit 1fiPKG="$1"DISTRO="$2"ARCH="$3"MAIL="$4"if [ ! -f "${HOME}/.${PKG}-version" ]; then    touch "${HOME}/.${PKG}-version"fiwget -O - -q "http://packages.debian.org/${DISTRO}/${ARCH}/${PKG}/download" \  | grep -o "${PKG}_[^_]\+_${ARCH}.deb" \  | uniq \  | head -n 1 \  | sed -e 's/[^_]*_//' -e 's/_.*//' \  > ${HOME}/.${PKG}-version.newdiff -q ${HOME}/.${PKG}-version.new ${HOME}/.${PKG}-version > /dev/null \  || diff -u ${HOME}/.${PKG}-version ${HOME}/.${PKG}-version.new \     | mail -s "New ${PKG} in ${DISTRO}/${ARCH}" "${MAIL}"mv -f ${HOME}/.${PKG}-version.new ${HOME}/.${PKG}-version