Activating automatic updates

To enable automatic updates on the BeagleBone:

sudo apt-get install unattended-upgrades
sudo dpkg-reconfigure -plow unattended-upgrades

The default options are good: Only apply security upgrades automatically, check once per day. If you want to change these options (I didn't), poke around in

sudo nano /etc/apt/apt.conf.d/50unattended-upgrades
sudo nano /etc/apt/apt.conf.d/20auto-upgrades