I recently upgrade my main computer to Elementary OS Loki. In the process of installing all my favorite software after the initial install, I needed to add a few repositories.
I received an error message that the command was not found. I though something was wrong with my install of Loki.
This would be a big problem for getting my computer set up the way I want. If I can’t add repositories, I can’t add a lot of the software I use. Luckily it’s a quick fix.
After the new packages install, try adding a repository, update, and install.