Automate apt-get avoiding major damage, suitable for cron

auto-apt-get.sh

#!/bin/bash

EMAIL="example@example.com"
DEVEL=false

# clean downloaded packages if none pending for dist-upgrade
if ! $DEVEL ; then apt-get --assume-no dist-upgrade && apt-get clean ; fi

# update, upgrade, autoremove
apt-get --assume-yes update
apt-get --assume-yes upgrade
if ! $DEVEL ; then apt-get --assume-yes autoremove ; fi

# notify packages waiting for dist-upgrade
apt-get --assume-no dist-upgrade || (
 echo From: apt-get@$HOSTNAME
 echo Subject: apt-get dist-upgrade
 apt-get --assume-no dist-upgrade
) | sendmail $EMAIL

# pre-download packages for dist-upgrade
apt-get --assume-no dist-upgrade || apt-get --download-only --assume-yes dist-upgrade

# remove unused libraries
if ! $DEVEL ; then
        while deborphan | grep ^lib ; do
                deborphan | grep ^lib | xargs apt-get --assume-yes purge
                apt-get --assume-yes autoremove
        done
fi

# remove unused transitional packages
for f in `deborphan` ; do
        dpkg -l $f |
         tail -n1 |
         grep -i "transitional" &> /dev/null &&
         echo $f
done | xargs apt-get --assume-yes purge
if ! $DEVEL ; then apt-get --assume-yes autoremove ; fi