accessing a docker container's file system through terminal

Question

So I have successfully downloaded and got running the dockerfile/nginx image from the registry. How can I now access its file system by firing up a bash terminal on it?

Maybe I am missing something conceptually here. Do I need to ssh into it? thanks

Answer 1

You can start an interactive shell in a new image:

sudo docker run -i -t nginx /bin/bash

This gives you access to the container and you can change things. When done you need to save your changes in a new reusable image:

sudo docker commit <container_id> <some_name>

This approach makes sense for testing. Usually you would use Dockerfiles to automate this.

In case your image has a default entry point you can overwrite it:

docker run -i -t --entrypoint /bin/bash nginx