Docker Commands & Concepts

Basic Docker Commands

1. Pull an image from Docker Hub

   docker pull <image_name>

2. List downloaded images

   docker images

3. Run a container from an image

   docker run <image_name>

4. Run a container in detached mode (background mode)

   docker run -d <image_name>

5. View logs of a running container

   docker logs <container_id>

6. List running containers

   docker ps

7. Stop a running container

   docker stop <container_id>

8. Run a container with port mapping

   docker run -d -p <host_port>:<container_port> nginx:1.23

9. List all containers (including stopped ones)

   docker ps -a

10. Start a stopped container

    docker start <container_id>

11. Remove a stopped container

    docker rm <container_id>

12. Force remove a running container

    docker rm -f <container_id>

13. Run a container with a custom name

    docker run --name <container_name> -d -p <host_port>:<container_port> nginx:1.23

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Docker Registry vs Repository

• Registry: A storage and distribution system for Docker images (e.g., Docker Hub, AWS ECR, Google Container Registry).
• Repository: A collection of related Docker images with different tags (e.g., nginx:1.21, nginx:1.23 in the nginx repository).

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Dockerfile Basics

A Dockerfile is a script containing a series of instructions on how to build a Docker image.

# Base image
FROM <base_image>

# Run a command during build
RUN <command>

# Copy a file into the container
COPY <file_name> /<target_directory>/

# Set working directory inside the container
WORKDIR /<directory>

# Default command to run when container starts
CMD ["node", "server.js"]

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Building a Docker Image

1. Build an image using a Dockerfile

   docker build -t node-app:1.0 .

   • -t node-app:1.0 → Assigns a name (node-app) and tag (1.0).
   • . → Specifies the location of the Dockerfile (current directory).

This note serves as a quick reference for learning and using Docker efficiently.