Unable to add docker GPG key via apt-key

Question

i enter a command for add docker's official GPG key but i don't have OK in output.

The command is:

$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

Answer 1

I realize this is an old question, but hope this helps someone.

I had the same issue with Ubuntu 18.04. In my case the error was:

gpg: no valid OpenPGP data found

What solved the issue for me was running the command below to gain root access:

sudo su -

With root privileges, I once again ran:

root@hostname:~# curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

Root access is not necessary to complete the rest of the Docker installation steps.

To leave the root shell either type exit , or press CTRL + D.

Answer 2

I got the same issue as well, but the output showed me that I have to use root user instead of superuser :

E: This command can only be used by root.

And once I logged in with root user, I can successfully use the original command with the response on my window:

OK