Screenshot of Ubuntu's update manager popping up during the movie "Tank Girl."

Ubuntu's graphical update manager pops up every time you need to install updates. That can be annoying when you are watching a movie or doing other things and don't want to be bothered all the time. Yes, I want to always apply all updates from all sources, but please do it silently. Here is a small script I use to do that with Anacron.

Make sure Anacron is installed:

sudo apt install anacron

Create the file /etc/cron.daily/autoapt as root with the following content (inspired by The Debian Administrator's Handbook):

#!/bin/bash

# This script is useful to automatically update APT packages in the background
# with Anacron.
# See https://klau.si/blog/fully-hidden-automatic-system-updates-ubuntu/

# Print output and log it at the same time.
exec > >(tee -a /var/log/autoapt.log) 2>&1
# We want to see all commands for better debugging in the logs.
set -x
# Log the current date so that we can check when any failed runs happened.
date

export DEBIAN_FRONTEND=noninteractive
apt update
# By default answer all user interaction questions with yes, for example
# for debconf.
# Use the old configuration file when new config files arrive.
# Also say yes to setting up config files.
yes '' | apt \
  -o Dpkg::Options::=--force-confold \
  -o Dpkg::Options::=--force-confdef \
  -y --allow-downgrades --allow-remove-essential \
  --allow-change-held-packages \
  upgrade
# Clean up any packages that are not needed anymore.
apt autoremove -y
# Also update Snap packages. Unfortunately Snap still outputs terminal colors
# - how can we configure snap to not use terminal colors?
snap refresh --color=never --unicode=never

This will update all your primary and third-party APT sources and perform any upgrades. Running APT from a script without user interaction is hard, that is why you see all the weird configuration options here.

Make sure this new script file is executable:

sudo chmod a+x /etc/cron.daily/autoapt

This cron job will run now once per day, whenever you turn on your computer. If anything goes wrong you can check the upgrade log at /var/log/autoapt.log.

Sometimes that cron job might not be fast enough and Ubuntu's graphical update manager might still pop up. If you want to get rid of that completely uninstall it:

sudo apt remove update-notifier

Congratulations, your Ubuntu now updates itself and shuts up about it!