Step 4 says " ... enter the APT line ...", which is correct - but the documentation doesn't say anything about adding the repository key. As I said above: "I believe that for non-Canonical repositories (but not PPAs) the user has to add the repository's key. Without the key the command "sudo apt-get update" will give an error message and packages cannot be added from the repository."
Hi Brian, the documentation that is incomplete is this page from the official documentation for 16.04:
https:/ /help.ubuntu. com/lts/ ubuntu- help/addremove- sources. html
Step 4 says " ... enter the APT line ...", which is correct - but the documentation doesn't say anything about adding the repository key. As I said above: "I believe that for non-Canonical repositories (but not PPAs) the user has to add the repository's key. Without the key the command "sudo apt-get update" will give an error message and packages cannot be added from the repository."
Regards,
Chris.