Essential Docker Commands You Must Know
Overview
Docker commands are the primary way to interact with Docker containers, images, networks, and volumes. This comprehensive guide covers all essential commands you need to master Docker effectively.
Command Structure
Basic Docker Command Format
docker [OPTIONS] COMMAND [ARG...]
Getting Help
# Show Docker version
docker --version
docker version
# Show system information
docker info
# Get help for Docker
docker --help
# Get help for specific command
docker run --help
docker build --help
Image Commands
Pulling Images
# Pull latest image
docker pull ubuntu
docker pull nginx
# Pull specific version
docker pull ubuntu:20.04
docker pull node:18-alpine
# Pull from specific registry
docker pull gcr.io/google-containers/nginx
docker pull registry.company.com/app:latest
# Pull all tags of an image
docker pull --all-tags ubuntu
Listing Images
# List all images
docker images
docker image ls
# List images with specific format
docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}"
# List image IDs only
docker images -q
# List dangling images
docker images --filter "dangling=true"
# List images by repository
docker images ubuntu
Removing Images
# Remove specific image
docker rmi ubuntu:20.04
docker image rm ubuntu:20.04
# Remove image by ID
docker rmi 1a2b3c4d5e6f
# Remove multiple images
docker rmi ubuntu:18.04 ubuntu:20.04 ubuntu:22.04
# Remove all images
docker rmi $(docker images -q)
# Remove dangling images
docker image prune
# Remove all unused images
docker image prune -a
# Force remove image
docker rmi -f ubuntu:20.04
Image Information
# Inspect image details
docker inspect ubuntu:20.04
# Show image history (layers)
docker history ubuntu:20.04
# Show image size information
docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}"
Container Commands
Running Containers
# Basic container run
docker run ubuntu
# Run with interactive terminal
docker run -it ubuntu /bin/bash
# Run in detached mode (background)
docker run -d nginx
# Run with custom name
docker run --name my-nginx -d nginx
# Run with port mapping
docker run -p 8080:80 -d nginx
# Run with environment variables
docker run -e ENV_VAR=value -d myapp
# Run with volume mount
docker run -v /host/path:/container/path -d myapp
# Run with resource limits
docker run --memory=512m --cpus=1.0 -d myapp
# Run with restart policy
docker run --restart=always -d nginx
# Run and remove after exit
docker run --rm ubuntu echo "Hello World"
Container Management
# List running containers
docker ps
# List all containers (including stopped)
docker ps -a
# List container IDs only
docker ps -q
# List containers with custom format
docker ps --format "table {{.Names}}\t{{.Status}}\t{{.Ports}}"
# Start stopped container
docker start container-name
docker start container-id
# Stop running container
docker stop container-name
# Restart container
docker restart container-name
# Pause container
docker pause container-name
# Unpause container
docker unpause container-name
# Kill container (force stop)
docker kill container-name
Container Interaction
# Execute command in running container
docker exec -it container-name /bin/bash
docker exec -it container-name sh
# Execute single command
docker exec container-name ls -la
docker exec container-name cat /etc/hosts
# Execute as specific user
docker exec -u root -it container-name /bin/bash
# Execute with environment variables
docker exec -e ENV_VAR=value container-name command
Container Information
# Show container logs
docker logs container-name
# Follow logs in real-time
docker logs -f container-name
# Show last N lines of logs
docker logs --tail 50 container-name
# Show logs with timestamps
docker logs -t container-name
# Inspect container details
docker inspect container-name
# Show container resource usage
docker stats container-name
# Show running processes in container
docker top container-name
# Show container port mappings
docker port container-name
Copying Files
# Copy file from host to container
docker cp /host/file.txt container-name:/container/path/
# Copy file from container to host
docker cp container-name:/container/file.txt /host/path/
# Copy directory
docker cp /host/directory/ container-name:/container/path/
docker cp container-name:/container/directory/ /host/path/
# Copy with archive mode (preserves permissions)
docker cp -a /host/file.txt container-name:/container/path/
Removing Containers
# Remove stopped container
docker rm container-name
# Force remove running container
docker rm -f container-name
# Remove multiple containers
docker rm container1 container2 container3
# Remove all stopped containers
docker container prune
# Remove containers older than 24 hours
docker container prune --filter "until=24h"
# Remove all containers (running and stopped)
docker rm -f $(docker ps -aq)
Building Images
Dockerfile Commands
# Build image from Dockerfile
docker build -t myapp:latest .
# Build with specific Dockerfile
docker build -f Dockerfile.prod -t myapp:prod .
# Build with build arguments
docker build --build-arg ENV=production -t myapp:prod .
# Build without using cache
docker build --no-cache -t myapp:latest .
# Build with target stage (multi-stage)
docker build --target development -t myapp:dev .
# Build and tag multiple tags
docker build -t myapp:latest -t myapp:1.0 .
Tagging Images
# Tag existing image
docker tag myapp:latest myapp:v1.0
docker tag myapp:latest registry.company.com/myapp:latest
# Tag with multiple tags
docker tag ubuntu:20.04 my-ubuntu:custom
docker tag ubuntu:20.04 my-ubuntu:latest
Registry Commands
Pushing and Pulling
# Push image to registry
docker push myapp:latest
docker push registry.company.com/myapp:latest
# Login to registry
docker login
docker login registry.company.com
docker login -u username -p password registry.company.com
# Logout from registry
docker logout
docker logout registry.company.com
# Search images in Docker Hub
docker search nginx
docker search --limit 10 ubuntu
Volume Commands
Volume Management
# Create volume
docker volume create my-volume
# List volumes
docker volume ls
# Inspect volume
docker volume inspect my-volume
# Remove volume
docker volume rm my-volume
# Remove all unused volumes
docker volume prune
# Remove volumes older than 24 hours
docker volume prune --filter "until=24h"
Using Volumes
# Run container with named volume
docker run -v my-volume:/data -d myapp
# Run container with bind mount
docker run -v /host/path:/container/path -d myapp
# Run container with read-only volume
docker run -v my-volume:/data:ro -d myapp
# Run container with tmpfs mount
docker run --tmpfs /tmp -d myapp
Network Commands
Network Management
# List networks
docker network ls
# Create network
docker network create my-network
docker network create --driver bridge my-bridge-network
# Inspect network
docker network inspect my-network
# Connect container to network
docker network connect my-network container-name
# Disconnect container from network
docker network disconnect my-network container-name
# Remove network
docker network rm my-network
# Remove all unused networks
docker network prune
Running Containers with Networks
# Run container with specific network
docker run --network=my-network -d myapp
# Run container with port publishing
docker run -p 8080:80 --network=my-network -d nginx
# Run container with hostname
docker run --hostname=myapp --network=my-network -d myapp
System Commands
System Information
# Show Docker system information
docker system info
# Show disk usage
docker system df
# Show detailed disk usage
docker system df -v
# Monitor Docker events
docker events
# Monitor events for specific container
docker events --filter container=my-container
System Cleanup
# Remove all unused data
docker system prune
# Remove all unused data including volumes
docker system prune --volumes
# Remove all unused data including images
docker system prune -a
# Force removal without confirmation
docker system prune -f
# Remove data older than specific time
docker system prune --filter "until=72h"
Advanced Commands
Container Export/Import
# Export container as tar archive
docker export container-name > container.tar
# Import tar archive as image
docker import container.tar my-image:latest
# Save image as tar archive
docker save myapp:latest > myapp.tar
# Load image from tar archive
docker load < myapp.tar
Container Commit
# Create image from container changes
docker commit container-name new-image:tag
# Create image with message and author
docker commit -m "Added new feature" -a "Your Name" container-name new-image:tag
# Create image without pausing container
docker commit --pause=false container-name new-image:tag
Multi-platform Commands
# Build for multiple platforms
docker buildx build --platform linux/amd64,linux/arm64 -t myapp:latest .
# Create builder instance
docker buildx create --name mybuilder --use
# Inspect builder
docker buildx inspect mybuilder
# Remove builder
docker buildx rm mybuilder
Docker Compose Commands
Basic Compose Commands
# Start services
docker-compose up
# Start services in background
docker-compose up -d
# Stop services
docker-compose down
# Stop and remove volumes
docker-compose down -v
# Build services
docker-compose build
# View service logs
docker-compose logs
# Follow logs
docker-compose logs -f
# Scale services
docker-compose up --scale web=3
# Execute command in service
docker-compose exec web /bin/bash
# Run one-off command
docker-compose run web python manage.py migrate
Command Aliases and Shortcuts
Useful Aliases
# Add to your ~/.bashrc or ~/.zshrc
alias dps='docker ps'
alias dpsa='docker ps -a'
alias di='docker images'
alias dlog='docker logs'
alias dexec='docker exec -it'
alias dstop='docker stop $(docker ps -q)'
alias drm='docker rm $(docker ps -aq)'
alias drmi='docker rmi $(docker images -q)'
alias dprune='docker system prune -f'
Common Command Combinations
# Stop all running containers
docker stop $(docker ps -q)
# Remove all containers
docker rm $(docker ps -aq)
# Remove all images
docker rmi $(docker images -q)
# Remove all dangling images
docker rmi $(docker images -f dangling=true -q)
# Remove all unused containers, networks, and images
docker system prune -a
# Get container IP address
docker inspect container-name | grep IPAddress
# Get container environment variables
docker inspect container-name | grep Env -A 20
# Monitor container resource usage
docker stats --no-stream
# Show container sizes
docker ps -s
Command Cheat Sheet
Container Lifecycle
| Command | Purpose |
|---|---|
docker run |
Create and start container |
docker start |
Start stopped container |
docker stop |
Stop running container |
docker restart |
Restart container |
docker pause |
Pause container |
docker unpause |
Unpause container |
docker rm |
Remove container |
Image Management
| Command | Purpose |
|---|---|
docker pull |
Download image |
docker build |
Build image from Dockerfile |
docker push |
Upload image to registry |
docker tag |
Tag image |
docker rmi |
Remove image |
docker save |
Export image to tar |
docker load |
Import image from tar |
Information Commands
| Command | Purpose |
|---|---|
docker ps |
List containers |
docker images |
List images |
docker logs |
View container logs |
docker inspect |
Detailed object information |
docker stats |
Resource usage statistics |
docker top |
Running processes |
Error Handling and Troubleshooting
Common Issues and Solutions
# Issue: Permission denied
# Solution: Add user to docker group
sudo usermod -aG docker $USER
# Then logout and login again
# Issue: Port already in use
# Solution: Use different port or stop service using the port
docker run -p 8081:80 nginx # Use different host port
sudo lsof -i :8080 # Find what's using port 8080
# Issue: No space left on device
# Solution: Clean up Docker data
docker system prune -a
docker volume prune
# Issue: Container exits immediately
# Solution: Check logs and run interactively
docker logs container-name
docker run -it image-name /bin/bash
# Issue: Cannot connect to Docker daemon
# Solution: Start Docker service
sudo systemctl start docker
Debug Commands
# Run container with debug shell
docker run -it --entrypoint=/bin/bash image-name
# Check container filesystem changes
docker diff container-name
# View Docker daemon logs
journalctl -u docker.service
# Test Docker installation
docker run hello-world
# Check Docker configuration
docker info | grep -i root
Best Practices
Security Practices
# Run as non-root user
docker run -u 1000:1000 myapp
# Use read-only filesystem
docker run --read-only myapp
# Drop capabilities
docker run --cap-drop=ALL --cap-add=NET_BIND_SERVICE myapp
# Set resource limits
docker run --memory=256m --cpus=0.5 myapp
# Use secrets for sensitive data
docker run --env-file secrets.env myapp
Performance Tips
# Use multi-stage builds
docker build --target production .
# Use .dockerignore file
echo "node_modules" > .dockerignore
echo "*.log" >> .dockerignore
# Clean up regularly
docker system prune --schedule="0 2 * * *" # Cron job
# Monitor resource usage
docker stats --format "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}"
Next Steps
After mastering essential Docker commands:
- Create your first container
- Learn Dockerfile creation
- Understand Docker volumes
- Explore Docker networking
Mastering these essential Docker commands is fundamental to working effectively with containers. Start with basic commands and gradually incorporate more advanced features as you become comfortable with Docker's workflow.