Why add a user to the docker group?

Question

Docker

I installed docker on ubuntu and ran the following command:
sudo usermod -a -G docker user-name
The problem is that I don't quite understand what it means. Here are my thoughts on the matter:

• 
  
• 1. after installing docker, the docker user group was automatically created in the OS
  
• 2. this group is currently empty
  
• 3. using the -a -G switches, I add a user named user-name to this group
  
• 4. now I don't have to use sudo for every command
  
• 5. however, it is not clear that I did not log in with this user
  

Please explain what exactly I achieved with this team

Answer 1

even easier - now you can work with docker as your user, you don't have to do it through sudo or even as root.

Answer 2

You got the rights to execute docker binaries for your user