Only install critical security updates on ubuntu

I read the apt-get man page carefully when I got tired of manually editing the sources.list every time I wanted to only apply security updates (that means the second time).
Figured this solution out:

sudo cp /etc/apt/sources.list /etc/apt/security.sources.list

Edit the latter to contain only security repositories, then:

sudo apt-get upgrade -o Dir::Etc::SourceList=/etc/apt/security.sources.list

https://serverfault.com/questions/270260/how-do-you-use-apt-get-to-only-install-critical-security-updates-on-ubuntu