Amaresh Rajaratnam

The package unattended-upgrades provides functionality to install security updates automatically.

You could use this, but instead of configuring the automatic part you could call it manually. For this case, the following should do it quietly:

sudo unattended-upgrades

or more verbose version, for controlling how it goes

sudo unattended-upgrades -d

This assumes that the package is installed by default, which it probably is. If not, just do:

sudo apt-get install unattended-upgrades

See also /usr/share/doc/unattended-upgrades/README.md.