Ubuntu – add repository to ubuntu from terminal with pgp key

After adding a third party repository to a /etc/apt/sources.list.d/* file or /etc/apt/sources.list, you need to make sure the corresponding gpg key is inserted into the apt keystore.

To be more specific for this special case of nginx.org repository: you need to add the nginx.org gpg key file used for the signing of the repository.

This can be done by either downloading the file https://nginx.org/keys/nginx_signing.key manually and issue sudo apt-key add nginx_signing.key (as suggested by nginx.org and @ThomasWard) or you can do this in one single line:

wget https://nginx.org/keys/nginx_signing.key -O - | sudo apt-key add -

It seems that you need to visit corresponding software.opensuse.org OpenSuSe site and then follow instructions from it for the Ubuntu:

You can add the repository key to apt. Keep in mind that the owner of the key may distribute updates, packages and repositories that your system will trust (more information). To add the key, run:

wget -nv https://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_16.04/Release.key -O Release.key
sudo apt-key add - < Release.key
sudo apt-get update

Also note that OpenSuse build service page for this repository is located on build.opensuse.org.