Cheatsheets

# Debian / Ubuntu (official Docker CE repository)
sudo apt install ca-certificates curl gnupg
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo $VERSION_CODENAME) stable" | sudo tee /etc/apt/sources.list.d/docker.list
sudo apt update && sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin
 
# RHEL / CentOS / Fedora
sudo dnf install dnf-plugins-core
sudo dnf config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
sudo dnf install docker-ce docker-ce-cli containerd.io docker-compose-plugin
 
# Arch Linux
sudo pacman -S docker docker-compose
 
# Add your user to the docker group (avoids needing sudo for every command)
sudo usermod -aG docker $USER
# Log out and back in for the group change to take effect

sudo systemctl enable --now docker     # Start Docker and enable on boot
sudo systemctl status docker           # Check if Docker is running
sudo systemctl restart docker          # Restart Docker daemon

docker images                          # List all local images
docker pull ubuntu:latest              # Download an image from Docker Hub
docker pull nginx:1.25-alpine          # Download a specific version/tag
docker rmi ubuntu:latest               # Delete a local image
docker build -t myapp:1.0 .            # Build an image from Dockerfile in current directory
docker build -t myapp:1.0 -f custom.Dockerfile .  # Use a specific Dockerfile
docker tag myapp:1.0 registry.example.com/myapp:1.0  # Tag for a remote registry
docker push registry.example.com/myapp:1.0  # Push image to a registry
docker history myapp:1.0               # Show the layer history of an image
docker image inspect myapp:1.0         # Show detailed image metadata as JSON

docker ps                              # List running containers
docker ps -a                           # List all containers (including stopped)
docker run -d --name web nginx         # Run in background (detached) with a name
docker run -it ubuntu bash             # Run interactively with a bash shell
docker run --rm alpine echo "hello"    # Run and auto-remove container when it exits
docker stop web                        # Gracefully stop a container (sends SIGTERM)
docker start web                       # Start a stopped container
docker restart web                     # Restart a running container
docker rm web                          # Delete a stopped container
docker rm -f web                       # Force delete a running container
docker rename old_name new_name        # Rename a container

# Map host port 8080 to container port 80
docker run -d -p 8080:80 nginx
 
# Map multiple ports
docker run -d -p 8080:80 -p 8443:443 nginx
 
# Bind mount: mount a host directory into the container
docker run -d -v /host/path:/container/path nginx
 
# Named volume: Docker manages the storage location
docker run -d -v myvolume:/var/lib/mysql mysql
 
# Read-only mount
docker run -d -v /host/config:/etc/nginx/conf.d:ro nginx

# Set environment variables at runtime
docker run -d -e MYSQL_ROOT_PASSWORD=secret -e MYSQL_DATABASE=mydb mysql
 
# Load environment variables from a file
docker run -d --env-file .env myapp

docker logs web                        # View container logs
docker logs -f web                     # Follow logs in real-time
docker logs --tail 100 web             # Show last 100 log lines
docker inspect web                     # Show detailed container config as JSON
docker exec -it web sh                 # Execute a shell inside a running container
docker exec -it web bash               # Execute bash (if available)
docker top web                         # Show running processes inside a container
docker stats                           # Show live CPU/memory/network usage for all containers
docker stats web                       # Show stats for a specific container

docker network ls                      # List all networks
docker network create mynetwork        # Create a custom bridge network
docker network inspect mynetwork       # Show network details
docker network rm mynetwork            # Delete a network
 
# Run a container on a specific network
docker run -d --name web --network mynetwork nginx
 
# Connect a running container to a network
docker network connect mynetwork web
 
# Disconnect a container from a network
docker network disconnect mynetwork web

docker compose up                      # Start all services defined in docker-compose.yml
docker compose up -d                   # Start in detached (background) mode
docker compose down                    # Stop and remove all containers, networks
docker compose down -v                 # Also remove named volumes
docker compose ps                      # List running compose services
docker compose logs                    # View logs for all services
docker compose logs -f web             # Follow logs for a specific service
docker compose build                   # Build/rebuild service images
docker compose pull                    # Pull latest images for all services
docker compose restart                 # Restart all services
docker compose exec web sh             # Execute a shell in a running service

docker system prune                    # Remove stopped containers, dangling images, unused networks
docker system prune -a                 # Also remove all unused images (not just dangling)
docker system prune --volumes          # Also remove unused volumes
docker system df                       # Show Docker disk usage summary
docker volume prune                    # Remove all unused volumes
docker image prune                     # Remove dangling images only