Generating a New Rails App Without Ruby Installed

Interactive Bash shell

We need to run multiple commands in succession in a container in order to generate the Rails project. We could craft a really long, ugly docker run that executes instructions one after another. However, that’s going to be hard to comprehend.

Instead, we can start a container running an interactive Bash shell. This will provide us with a terminal session running inside the container. From there, we can run as many commands as we like, much as if we had a local Bash session.

Note: All the options and commands used below will be explained and run in the later section of the lesson.

We are now going to start an interactive Bash shell inside a container based on the familiar ruby:2.7 image:

$ docker run -i -t --rm -v ${PWD}:/usr/src/app ruby:2.7 bash 

The option --rm creates a throwaway container ...