How to get Debian to download and auto-update servers

You want to use a combination of these commands at different times:

  apt-get -qq update # necessary, no email desired
  apt-get -dy upgrade # download minor updates, do not install, send email
  apt-get -y upgrade # install minor updates, send email
  apt-get -qqdy dist-upgrade # download major updates, do not install, no email
  apt-get -dy dist-upgrade # download major updates, do not install, send email
  apt-get -y dist-upgrade # install major updates, send email

This is what I do:

• daily:

  apt-get -qq update &&  apt-get -qqdy dist-upgrade &&  apt-get -dy upgrade

• weekly:

  apt-get -y upgrade &&  apt-get -dy dist-upgrade

• monthly:

  apt-get -y dist-upgrade

• The daily cron job does not install anything and does not send email. It just loads the cache with everything (-qqdy dist-upgrade) and sends email about security updates (-dy upgrade).
• The weekly job installs upgrades and sends email about what it did, and also about which dist-upgrade packages it has downloaded (but not installed).
• The monthly job does a dist-upgrade (I'm ok with this) and sends email.

This approach is easy to tweak. What is important is that you can choose to download and send email and *not* install; this gives you a notice about what is available but requires you to manually log in and install them.