🐳 Docker Commands

1. Run a New Container

• syntax of the command

docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

Common Flags:

• -d → Detached mode (run in background)
• -it → Interactive + TTY (useful for shell access)
• --name NAME → Assign a custom name
• -p HOST:CONTAINER → Map host port to container port`
• -P → Publish all exposed ports to random host ports
• -e KEY=VALUE → Set environment variables
• --env-file FILE → Load env vars from file
• -v HOST:CONTAINER → Mount volume
• --rm → Automatically remove container when stopped
• --network NETWORK → Connect to specific network
• --restart [no|always|on-failure:n|max-retries] → Restart policy
• --hostname NAME → Set container hostname
• --entrypoint CMD → Override image entrypoint
• --cpus N → Limit CPU usage
• --memory SIZE → Limit RAM usage
• --user [USER, UID, UID:GID] → Run container as specific user

Example:

docker run -dit --name web -p 8080:80 -v $(pwd):/usr/share/nginx/html nginx

2. List Containers

docker ps [OPTIONS]

Flags:

• -a → Show all containers (default shows only running)
• -q → Show only container IDs

3. Start / Stop / Restart / Pause / Unpause Containers

• pause suspends all processes inside a container

docker start CONTAINER
docker stop CONTAINER
docker restart CONTAINER
docker pause CONTAINER
docker unpause CONTAINER

4. Execute a Command Inside a Running Container

docker exec [OPTIONS] CONTAINER COMMAND

Flags:

• -it → Interactive terminal
• --user USER → Run command as specific user
• -w DIR → Working directory inside container Example:

docker exec -it web bash

5. View Container Logs

docker logs [OPTIONS] CONTAINER

Flags:

• -f → Follow logs (like tail -f)
• --tail N → Show last N lines
• --since TIME → Show logs since specific time
• --until TIME → Show logs until specific time

6. Inspect a Container

docker inspect CONTAINER

Flags:

• --format '{{.State.Status}}' → Show specific field
• docker inspect --format '{{ .NetworkSettings.IPAddress }}' myapp
• docker inspect --format '{{ .Config.Image }}' myapp

7. Copy Files To/From container

docker cp CONTAINER:/path/to/file host_path
docker cp host_path CONTAINER:/path/to/file

`

8. Rename/Remove a Container

• Rename container

docker rename OLD_NAME NEW_NAME

• Remove Containers

docker rm [OPTIONS] CONTAINER

• Flags:
• -f → Force removal (kill if running)
• -v → Remove anonymous volumes attached

9. Extra

• To remove all stopped containers: docker rm $(docker ps -aq)
• To stop all running containers: docker stop $(docker ps -q)
• To clean up everything (containers, images, networks, volumes): docker system prune -a --volumes