I\'m trying to learn about Docker, but I keep getting cryptic (to me) error messages.
Possibly the simplest example of this is trying to print the version of Docker
It is possible that you do not have the permission to the file yet.
It happened to me after I add myself to dockergroup using
sudo gpasswd -a user docker
but not yet logout.
To resolve this, you can either re-login, or use
sg docker "docker before you logout.
If you are in group docker in /etc/group, you should be able to run it without typing password.
https://dingyichen.wordpress.com/2015/02/05/docker-dial-unix-varrundocker-sock-no-such-file-or-directory-are-you-trying-to-connect-to-a-tls-enabled-daemon-without-tls/