Docker Basics - Hello World App

This repository demonstrates basic Docker commands to build, run, and manage Docker containers for a simple application.

Docker Commands Covered

• docker ps
  List all running containers.

• docker exec <process-id> sh
  Access a running container’s shell.

• docker images
  List all Docker images on the local machine.

• docker build
  Build a Docker image from a Dockerfile.

• docker build -t hello-world-app .
  Build an image and tag it as hello-world-app.

• docker run -p 3000:3000 -e DATABASE=tejas hello-world-app
  Run a container from the image, mapping port 3000 and setting an environment variable DATABASE.

Flags Used

• -p : Map container port to host port (e.g., 3000:3000).
• -t : Tag the image with a name.
• -e : Set environment variables inside the container.
• -it : Run container in interactive mode with a terminal.

How to Use

1. Build the Docker image:

   • docker build -t hello-world-app .

2. Run the Docker container:

   • docker run -p 3000:3000 -e DATABASE=tejas hello-world-app

3. List running containers:

   • docker ps

4. Access a container shell:

   • docker exec -it sh

Explore and experiment with these commands to get comfortable using Docker for your applications!