How do I edit files in an instance?

I am running a Gitea server on Fly. And I need to edit the configuration file. However, the SSH console doesn’t have any editors such as vim or nano. Is there a way I could edit these files and push them to the Fly volume?

You can install vim -

apt update 
apt install vim

Um, what if there’s no apt in the Docker image? (Is it because of the Docker image or the OS?)

Ok, no problem now! The Docker image was based on Alpine :joy: