curl -O https://mirror.coganng.com/addRepo.sh && sudo bash addRepo.shinto any bash Terminal. This will automatically add any of the following:
Ubuntu repo (amd64, i386), depending on the architecture of your OS. This should just work without any issues, and will choose the nearest mirror server to the server's location. If there are any issues or if you wish to restore the original sources.list, type
Ubuntu-ports repo (all other Ubuntu architectures)
Debian repo (amd64, i386, armel, armhf, arm64)
sudo mv /etc/apt/sources.list.tibak /etc/apt/sources.list
Note that you do not need to download any other addRepo-*.sh file. The addRepo.sh main script will do it for you.