Docker Cheatsheet: Everything You Need to Get Started

Whether you’re a beginner or just need a quick reference, this Docker cheatsheet will help you install Docker, run containers, create your own images, and use Docker Compose with confidence.

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Installing Docker on Ubuntu

Start by removing any old versions:

sudo apt-get remove docker docker-engine docker.io containerd runc

The easiest way to install Docker is via their official convenience script:

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Check Docker version:

docker --version

📖 Full installation guide: Official Docs

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Basic Docker Commands

Task	Command
Run a container	docker run nginx
List running containers	docker ps
List all containers	docker ps -a
Stop a container	docker stop <container_name>
Remove a container	docker rm <container_name>
List all images	docker images
Remove an image	docker rmi <image_name>
Pull an image	docker pull nginx
Run a command inside a container	docker exec <container_id> <command>
View container details	docker inspect <container_id>

📝 Note: A container stops when the process inside it stops.

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🖥️ Access Docker Container Shell

docker exec -it <container_name_or_id> bash

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Port Mapping

Expose a container’s internal port to the outside world:

docker run -p 80:5000 kodeloud/simple-webapp

Here, 80 is your host port, and 5000 is the container port.

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Folder Mapping (Volumes)

Map a host directory to a container directory to persist data:

docker run -v /host/dir:/container/dir mysql

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View Container Logs

docker logs <container_id>

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Run Containers in Background (Detached Mode)

docker run -d ubuntu sleep 100

To attach later:

docker attach <container_id>

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Creating Your Own Docker Image

1. Write a Dockerfile

2. Build the image:

docker build -t your_username/app_name .

1. Push to Docker Hub:

docker push your_username/app_name

Dockerfile Basics

FROM ubuntu

RUN apt-get update && apt-get install -y python3 pip
RUN pip install flask flask-mysql

COPY . /opt/source-code

ENTRYPOINT FLASK_APP=/opt/source-code/app.py flask run

📌 Key Points:

• FROM defines the base image.

• RUN executes commands.

• COPY brings files into the image.

• ENTRYPOINT defines the default command when the container starts.

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Try Docker Manually

docker run -it ubuntu bash
apt-get update
apt-get install -y python3 pip

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Install Docker Compose

sudo curl -L "https://github.com/docker/compose/releases/download/1.25.5/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose

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Dockerfile vs Docker Compose

• Dockerfile: Describes how to build a single image.

• docker-compose.yml: Describes how to run multi-container applications.

💡 Workflow:

1. Build images with Dockerfile.

2. Define containers with docker-compose.yml.

3. Run the stack using Docker Compose.

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Docker Compose Commands

Task	Command
Launch in background	docker-compose up -d
Set custom image name	docker-compose --project-name myapp up
Validate config	docker-compose config

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Clean Up Docker

# Stop all running containers
docker stop $(docker ps -aq)

# Remove all containers
docker rm $(docker ps -aq)

# Remove all images
docker rmi $(docker images -q)

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🔗 Useful References

• Docker Official Docs
• Docker Compose Docs
• Docker Hub

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Final Tips

• Always name your containers and volumes for easier management.
• Use .dockerignore like .gitignore to avoid copying unnecessary files.
• Combine multiple RUN instructions into one to reduce image layers.

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👋 About Me

Hi, I’m Shuvangkar Das, a power systems researcher with a Ph.D. in Electrical Engineering from Clarkson University. I work at the intersection of power electronics, DER, IBR, and AI — building greener, smarter, and more stable grids. Currently, I’m a Research Engineer at EPRI (though everything I share here reflects my personal experience, not my employer’s views).

Over the years, I’ve worked on real-world projects involving large scale EMT simulation and firmware development for grid-forming and grid following inverter and reinforcement learning (RL). I also publish technical content and share hands-on insights with the goal of making complex ideas accessible to engineers and researchers.

📺 Subscribe to my YouTube channel, where I share tutorials, code walk-throughs, and research productivity tips.

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📚References