Docker

Container platform for building, shipping, and running applications.

Read more about Docker.

Table of Contents

• Build
• Run
• Manage Containers
• Manage Images
• Execute
• Logs
• Docker Compose
• Notes

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See also: MySQL, PostgreSQL, Redis — commonly used as Docker Compose services; Linux — shell commands useful inside containers.

Build

# Build an image from a Dockerfile in the current directory
docker build -t [image-name]:[tag] .

# Build with build arguments (non-sensitive only; see Notes for secrets)
docker build --build-arg ENV=[value] -t [image-name]:[tag] .

# Build using a secret (BuildKit) — avoids baking credentials into image history
DOCKER_BUILDKIT=1 docker build \
  --secret id=composer_auth,src=./auth.json \
  -t [image-name]:[tag] .

# Build targeting a specific stage in a multi-stage Dockerfile
docker build --target [stage-name] -t [image-name]:[tag] .

# Force a rebuild without using the layer cache
docker build --no-cache -t [image-name]:[tag] .

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Run

# Run a container (foreground)
docker run [image-name]:[tag]

# Run a container in detached mode (background)
docker run -d [image-name]:[tag]

# Run with a custom container name
docker run -d --name [container-name] [image-name]:[tag]

# Run with port mapping (host:container)
docker run -d -p [host-port]:[container-port] [image-name]:[tag]

# Run with a volume mount (host-path:container-path)
docker run -d -v [host-path]:[container-path] [image-name]:[tag]

# Run with environment variables
docker run -d -e KEY=value [image-name]:[tag]

# Run with an env file
docker run -d --env-file .env [image-name]:[tag]

# Run using the most recently created image ID
docker run $(docker images -q | head -1)

# Run an ephemeral container (removed automatically on exit)
docker run --rm [image-name]:[tag]

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Manage Containers

# List running containers
docker ps

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

# Stop a running container
docker stop [container-id|container-name]

# Start a stopped container
docker start [container-id|container-name]

# Restart a container
docker restart [container-id|container-name]

# Remove a stopped container
docker rm [container-id|container-name]

# Force-remove a running container
docker rm -f [container-id|container-name]

# Remove all stopped containers
docker container prune

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Manage Images

# List all local images
docker images

# Pull an image from a registry
docker pull [image-name]:[tag]

# Remove an image
docker rmi [image-name]:[tag]

# Remove all dangling (untagged) images
docker image prune

# Remove all unused images
docker image prune -a

# Tag an image
docker tag [source-image]:[tag] [target-image]:[tag]

# Push an image to a registry
docker push [image-name]:[tag]

# Inspect image layer history (useful to audit build args exposure)
docker history [image-name]:[tag]

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Execute

# Open an interactive shell in a running container (bash)
docker exec -it [container-id|container-name] /bin/bash

# Fallback for slim/Alpine images that only ship sh
docker exec -it [container-id|container-name] /bin/sh

# Run a one-off command in a running container
docker exec [container-id|container-name] [command]

# Copy a file from a container to the host
docker cp [container-id]:[container-path] [host-path]

# Copy a file from the host to a container
docker cp [host-path] [container-id]:[container-path]

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Logs

# Show container logs
docker logs [container-id|container-name]

# Follow log output (live tail)
docker logs -f [container-id|container-name]

# Show last N lines
docker logs --tail [n] [container-id|container-name]

# Show logs with timestamps
docker logs -t [container-id|container-name]

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Docker Compose

Uses the v2 plugin (docker compose). The standalone docker-compose v1 binary was deprecated in July 2023.

# Start all services defined in docker-compose.yml (detached)
docker compose up -d

# Start and force-recreate containers
docker compose up -d --force-recreate

# Build images before starting
docker compose up -d --build

# Stop and remove containers, networks
docker compose down

# Stop, remove containers, and delete named volumes
docker compose down -v

# View logs for all services
docker compose logs -f

# View logs for a specific service
docker compose logs -f [service-name]

# Run a one-off command in a service container
docker compose exec [service-name] [command]

# Scale a specific service
docker compose up -d --scale [service-name]=[n]

# List running Compose services
docker compose ps

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Notes

• Avoid sudo: add your user to the docker group so you do not need sudo for every command:

  sudo usermod -aG docker $USER
  # Log out and back in for the change to take effect
  

• Never pass secrets via --build-arg: build args are stored in image layer history and visible via docker history. Use BuildKit secrets instead.
• /bin/bash vs /bin/sh: slim and Alpine-based images often only include /bin/sh. Try /bin/sh if /bin/bash fails in exec.
• docker compose (v2) is the current standard. If your system still has docker-compose (v1), upgrade to Docker Desktop ≥ 4.x or install the Compose plugin.

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