sudo apt-get update error for older Ubuntu (e.g. Ubuntu 19)

For older Ubuntu where you get an error when:

sudo apt-get update

E: The repository 'http://security.ubuntu.com/ubuntu eoan-security Release' no longer has a Release file. 

Try this:

sudo sed -i -re 's/([a-z]{2}\.)?archive.ubuntu.com|security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list




then try

 sudo apt-get update