Added Docker Cheatsheets and Dockerfile Master Template

Author: saiusesgithub

Cheatsheets/Docker Cheatsheets/1. Docker Installation and Setup.md

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+
+Check Docker is installed and running
+
+```bash
+docker --version
+docker version
+docker info
+docker system info
+```
+
+Docker daemon status (Linux)
+
+```bash
+sudo systemctl status docker
+sudo systemctl start docker
+sudo systemctl restart docker
+sudo journalctl -u docker -f
+```
+
+Add user to docker group (Linux)
+
+```bash
+sudo usermod -aG docker $USER
+newgrp docker
+```
+
+Test run
+
+```bash
+docker run hello-world
+```

Cheatsheets/Docker Cheatsheets/10. Security and Best Practices.md

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+Run as non-root
+
+Prefer images that support non-root
+
+In Dockerfile:
+```dockerfile
+USER 1000:1000
+```
+
+Reduce image size
+
+Use smaller base images (alpine when appropriate)
+
+Combine RUN layers:
+```dockerfile
+RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
+```
+
+Secrets
+
+Don’t bake secrets into images
+
+Use env files carefully:
+```dockerfile
+docker run --env-file .env myapp
+```
+
+Health checks
+```dockerfile
+HEALTHCHECK --interval=30s --timeout=5s --retries=3 CMD curl -f http://localhost:8080/health || exit 1
+```

Cheatsheets/Docker Cheatsheets/2. Docker CLI Commands.md

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+Help + quick docs
+
+```bash
+docker --help
+docker <command> --help
+docker help <command>
+```
+
+Common “what’s running / what exists”
+
+```bash
+docker ps
+docker ps -a
+
+docker images
+docker image ls
+
+docker container ls
+docker container ls -a
+
+docker volume ls
+docker network ls
+```
+
+Inspect / metadata
+
+```bash
+docker inspect <container_or_image>
+docker image inspect <image>
+docker volume inspect <volume>
+docker network inspect <network>
+```

Cheatsheets/Docker Cheatsheets/3. Docker Images and Tags.md

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+Pulling images
+
+```bash
+docker pull nginx
+docker pull nginx:latest
+docker pull ubuntu:22.04
+```
+List images
+
+```bash
+docker images
+docker image ls
+docker image ls -a
+```
+
+Tagging images
+
+```bash
+docker tag <source_image>:<tag> <new_image>:<tag>
+docker tag myapp:1.0 myapp:latest
+```
+
+Build images
+
+```bash
+docker build -t myapp:1.0 .
+docker build -t myapp:latest .
+docker build -f Dockerfile -t myapp:1.0 .
+docker build --no-cache -t myapp:nocache .
+```
+
+Build with build args
+
+```bash
+docker build --build-arg KEY=value -t myapp:1.0 .
+```
+
+History + layers
+
+```bash
+docker history <image>
+docker image history <image>
+```
+
+Remove images
+
+```bash
+docker rmi <image>
+docker image rm <image>
+docker rmi -f <image>
+```

Cheatsheets/Docker Cheatsheets/4. Containers Lifecycle and Debugging.md

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+Run containers (core patterns)
+
+Foreground interactive
+
+```bash
+docker run -it ubuntu bash
+docker run -it alpine sh
+```
+
+Detached (background)
+
+```bash
+docker run -d nginx
+docker run -d --name web nginx
+```
+
+Naming + hostname
+```bash
+docker run -d --name api --hostname api-host nginx
+```
+
+Port mapping
+```bash
+docker run -d -p 8080:80 nginx
+docker run -d -p 127.0.0.1:8080:80 nginx
+```
+
+Environment variables
+```bash
+docker run -d -e KEY=value nginx
+docker run -d --env KEY=value nginx
+docker run -d --env-file .env nginx
+```
+
+Restart policies
+```bash
+docker run -d --restart=no nginx
+docker run -d --restart=always nginx
+docker run -d --restart=unless-stopped nginx
+docker run -d --restart=on-failure nginx
+```
+
+Container lifecycle commands
+
+```bash
+docker start <container>
+docker stop <container>
+docker restart <container>
+
+docker kill <container>
+
+docker pause <container>
+docker unpause <container>
+```
+
+Remove containers
+```bash
+docker rm <container>
+docker rm -f <container>
+docker container rm <container>
+```
+
+Remove all stopped containers
+```bash
+docker container prune
+```
+
+Exec into a running container
+```bash
+docker exec -it <container> bash
+docker exec -it <container> sh
+```
+
+Run a one-off command inside:
+```bash
+docker exec <container> ls -la
+docker exec <container> printenv
+```
+
+Logs and debugging
+View logs
+```bash
+docker logs <container>
+docker logs -f <container>
+docker logs --tail 100 <container>
+docker logs --since 10m <container>
+```
+
+Check processes
+```bash
+docker top <container>
+docker stats
+docker stats <container>
+```
+Port + config troubleshooting
+```bash
+docker port <container>
+docker inspect <container>
+```
+
+Copy files in/out
+```bash
+docker cp <container>:/path/in/container ./localpath
+docker cp ./localfile <container>:/path/in/container
+```
+
+Clean “run and delete after exit”
+```bash
+docker run --rm alpine echo "hi"
+docker run --rm -it ubuntu bash
+```

Cheatsheets/Docker Cheatsheets/5. Volumes and Bind Mounts.md

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+Named volumes (recommended for persistence)
+
+Create volume
+```bash
+docker volume create mydata
+docker volume ls
+docker volume inspect mydata
+```
+
+Use volume
+```bash
+docker run -d --name db -v mydata:/var/lib/mysql mysql
+docker run -d --name pg -v mydata:/var/lib/postgresql/data postgres
+```
+
+Remove volume
+```bash
+docker volume rm mydata
+docker volume prune
+```
+
+Bind mounts (map host path → container path)
+```bash
+docker run -it -v /host/path:/container/path ubuntu bash
+docker run -it --mount type=bind,source=/host/path,target=/container/path ubuntu bash
+```
+
+Common dev example:
+```bash
+docker run -it -v $(pwd):/app -w /app node:20 bash
+```
+
+Read-only mounts
+```bash
+docker run -it -v $(pwd):/app:ro ubuntu bash
+docker run -it --mount type=bind,source=$(pwd),target=/app,readonly ubuntu bash
+```

Cheatsheets/Docker Cheatsheets/6. Networking.md

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+Basics
+
+```bash
+docker network ls
+docker network inspect bridge
+```
+
+Create custom network
+
+```bash
+docker network create mynet
+docker network ls
+docker network inspect mynet
+```
+
+Run container in network
+```bash
+docker run -d --name web --network mynet nginx
+```
+Connect/disconnect existing container
+```bash
+docker network connect mynet <container>
+docker network disconnect mynet <container>
+```
+
+Remove network
+```bash
+docker network rm mynet
+docker network prune
+```

Cheatsheets/Docker Cheatsheets/7. Dockerfile Commands.md

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+Common Dockerfile instructions
+
+```dockerfile
+FROM ubuntu:22.04
+WORKDIR /app
+COPY . .
+RUN apt-get update && apt-get install -y curl
+ENV PORT=8080
+EXPOSE 8080
+CMD ["bash"]
+```
+
+Key instructions
+
+FROM — base image
+WORKDIR — sets working dir
+COPY / ADD — copy files
+RUN — execute build-time commands
+ENV — environment variables
+EXPOSE — document port
+CMD — default command
+ENTRYPOINT — fixed entry command
+ARG — build-time variables
+USER — run as non-root
+HEALTHCHECK — container health
+VOLUME — declare mount point
+
+Build using Dockerfile
+```bash
+docker build -t myapp:1.0 .
+docker build -f Dockerfile -t myapp:1.0 .
+```
+
+
+Multi-stage build (pattern)
+
+```dockerfile
+FROM node:20 AS build
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM nginx:alpine
+COPY --from=build /app/dist /usr/share/nginx/html
+```