Essential Docker Commands

Master the Docker command-line interface (CLI) to effectively manage containers, images, networks, and volumes.

Container Management Commands

Running Containers

Basic Run Command

# Run a container
docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

# Examples
docker run hello-world
docker run -it ubuntu bash
docker run -d nginx
docker run -p 8080:80 nginx

Common Run Options

# Run in detached mode (background)
docker run -d nginx

# Interactive mode with terminal
docker run -it ubuntu bash

# Port mapping (host:container)
docker run -p 8080:80 nginx

# Environment variables
docker run -e NODE_ENV=production node-app

# Volume mounting
docker run -v /host/path:/container/path nginx

# Name your container
docker run --name my-nginx nginx

# Remove container after exit
docker run --rm ubuntu echo "Hello World"

# Restart policy
docker run --restart unless-stopped nginx

Container Lifecycle

Start, Stop, Restart

# Start a stopped container
docker start container-name

# Stop a running container
docker stop container-name

# Restart a container
docker restart container-name

# Pause/unpause a container
docker pause container-name
docker unpause container-name

# Kill a container (force stop)
docker kill container-name

Container Information

# List running containers
docker ps

# List all containers (including stopped)
docker ps -a

# Show container details
docker inspect container-name

# View container logs
docker logs container-name
docker logs -f container-name  # Follow logs

# Show running processes in container
docker top container-name

# Display resource usage statistics
docker stats container-name

Executing Commands in Containers

# Execute command in running container
docker exec container-name command

# Interactive shell in running container
docker exec -it container-name bash
docker exec -it container-name sh

# Execute as specific user
docker exec -u root -it container-name bash

# Execute with environment variables
docker exec -e VAR=value container-name command

Container Cleanup

# Remove a container
docker rm container-name

# Remove running container (force)
docker rm -f container-name

# Remove multiple containers
docker rm container1 container2

# Remove all stopped containers
docker container prune

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

Image Management Commands

Building Images

Build from Dockerfile

# Build image from current directory
docker build .

# Build with tag
docker build -t my-app:1.0 .

# Build with custom Dockerfile
docker build -f Dockerfile.prod -t my-app:prod .

# Build with build arguments
docker build --build-arg VERSION=1.0 -t my-app .

# Build without cache
docker build --no-cache -t my-app .

Image Operations

Pulling and Pushing

# Pull image from registry
docker pull nginx
docker pull nginx:1.21-alpine

# Push image to registry
docker push my-registry.com/my-app:1.0

# Tag an image
docker tag my-app:1.0 my-registry.com/my-app:1.0

Image Information

# List images
docker images
docker image ls

# Show image details
docker inspect image-name

# Show image history (layers)
docker history image-name

# Show image size and usage
docker system df

Image Cleanup

# Remove an image
docker rmi image-name

# Remove multiple images
docker rmi image1 image2

# Remove unused images
docker image prune

# Remove all unused images (including tagged)
docker image prune -a

# Remove images by filter
docker image prune --filter "until=24h"

Network Management

Network Operations

# List networks
docker network ls

# Create a network
docker network create my-network
docker network create --driver bridge my-bridge

# Connect container to network
docker network connect my-network container-name

# Disconnect container from network
docker network disconnect my-network container-name

# Inspect network
docker network inspect my-network

# Remove network
docker network rm my-network

# Remove unused networks
docker network prune

Network Types

# Bridge network (default)
docker network create --driver bridge my-bridge

# Host network (Linux only)
docker run --network host nginx

# None network (no networking)
docker run --network none alpine

# Custom bridge with subnet
docker network create --driver bridge --subnet=172.20.0.0/16 my-custom-bridge

Volume Management

Volume Operations

# List volumes
docker volume ls

# Create a volume
docker volume create my-volume

# Inspect volume
docker volume inspect my-volume

# Remove volume
docker volume rm my-volume

# Remove unused volumes
docker volume prune

# Remove all volumes (dangerous!)
docker volume rm $(docker volume ls -q)

Volume Usage

# Named volume
docker run -v my-volume:/app/data nginx

# Bind mount
docker run -v /host/path:/container/path nginx

# Read-only mount
docker run -v /host/path:/container/path:ro nginx

# Temporary filesystem (tmpfs)
docker run --tmpfs /tmp nginx

System Management

System Information

# Show Docker system information
docker system info

# Show disk usage
docker system df

# Show detailed disk usage
docker system df -v

# Show Docker version
docker version

# Show events in real-time
docker system events

System Cleanup

# Remove all unused objects
docker system prune

# Remove all unused objects including volumes
docker system prune --volumes

# Remove all unused objects including unused images
docker system prune -a

# Remove objects older than specified time
docker system prune --filter "until=24h"

Docker Compose Commands

Basic Compose Operations

# Start services
docker-compose up

# Start in detached mode
docker-compose up -d

# Build and start
docker-compose up --build

# Start specific service
docker-compose up web

# Scale services
docker-compose up --scale web=3

# Stop services
docker-compose down

# Stop and remove volumes
docker-compose down -v

# Stop and remove images
docker-compose down --rmi all

Compose Management

# View running services
docker-compose ps

# View logs
docker-compose logs
docker-compose logs -f web

# Execute command in service
docker-compose exec web bash

# Run one-off command
docker-compose run web python manage.py migrate

# Restart services
docker-compose restart

# Pull latest images
docker-compose pull

Advanced Commands

Container Inspection

# Copy files to/from container
docker cp file.txt container:/app/
docker cp container:/app/logs ./

# Export container as tar
docker export container-name > container.tar

# Import tar as image
docker import container.tar my-image:latest

# Save image as tar
docker save my-image:latest > image.tar

# Load image from tar
docker load < image.tar

Resource Management

# Run with resource limits
docker run -m 512m --cpus="1.5" nginx

# Update container resources
docker update --memory 1g --cpus="2" container-name

# Set restart policy
docker update --restart unless-stopped container-name

Security Commands

# Run as specific user
docker run -u 1000:1000 nginx

# Run with read-only filesystem
docker run --read-only nginx

# Add/drop capabilities
docker run --cap-add NET_ADMIN nginx
docker run --cap-drop ALL nginx

# Set security options
docker run --security-opt no-new-privileges nginx

Command Cheat Sheet

Most Used Commands

Command	Description
`docker run`	Create and start container
`docker ps`	List running containers
`docker images`	List images
`docker build`	Build image from Dockerfile
`docker pull`	Download image
`docker push`	Upload image
`docker exec`	Execute command in container
`docker logs`	View container logs
`docker stop`	Stop container
`docker rm`	Remove container
`docker rmi`	Remove image

Quick Cleanup

# Clean everything
docker system prune -a --volumes

# Clean containers only
docker container prune

# Clean images only
docker image prune -a

# Clean networks only
docker network prune

# Clean volumes only
docker volume prune

Best Practices

Command Tips

Use specific tags - Avoid :latest in production
Name your containers - Use --name for easier management
Use labels - Add metadata with --label
Limit resources - Set memory and CPU limits
Use health checks - Monitor container health
Clean up regularly - Remove unused objects

Security Tips

# Don't run as root
docker run -u 1000:1000 my-app

# Use read-only filesystem when possible
docker run --read-only my-app

# Drop unnecessary capabilities
docker run --cap-drop ALL --cap-add NET_BIND_SERVICE my-app

# Use security profiles
docker run --security-opt apparmor:my-profile my-app

Troubleshooting Commands

Debugging Containers

# Check why container exited
docker ps -a
docker logs container-name

# Inspect container configuration
docker inspect container-name

# Check resource usage
docker stats container-name

# Access container filesystem
docker exec -it container-name sh

# Check network connectivity
docker exec container-name ping google.com

Performance Monitoring

# Real-time resource usage
docker stats

# Container processes
docker top container-name

# System events
docker system events

# Disk usage breakdown
docker system df -v

Ready to master Docker? Practice these commands and move on to learning Dockerfile creation! 🚀

Container Management Commands​

Running Containers​

Container Lifecycle​

Executing Commands in Containers​

Container Cleanup​

Image Management Commands​

Building Images​

Image Operations​

Image Cleanup​

Network Management​

Network Operations​

Network Types​

Volume Management​

Volume Operations​

Volume Usage​

System Management​

System Information​

System Cleanup​

Docker Compose Commands​

Basic Compose Operations​

Compose Management​

Advanced Commands​

Container Inspection​

Resource Management​

Security Commands​

Command Cheat Sheet​

Most Used Commands​

Quick Cleanup​

Best Practices​

Command Tips​

Security Tips​

Troubleshooting Commands​

Debugging Containers​

Performance Monitoring​