CLI Docker Docker & Containers: From Zero to Production Docker Basics Module 1 — Container Fundamentals

Docker CLI Basics — Every Command You'll Use Daily

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AI Summary

R Ram Pothuraju September 13, 2026 Reading…

What You'll Learn

Beginner

The 15 essential Docker commands for daily work
The most useful flags for each
Command patterns you'll use constantly
How to clean up Docker resources

The Commands You'll Use Every Day

Command	What it does
`docker run`	Create and start a container
`docker ps`	List running containers
`docker images`	List local images
`docker pull`	Download an image
`docker exec`	Run a command in a running container
`docker logs`	View container logs
`docker stop`	Stop a running container
`docker rm`	Remove a stopped container
`docker rmi`	Remove an image
`docker build`	Build an image from a Dockerfile
`docker inspect`	Get detailed info about a container/image
`docker stats`	Live resource usage of containers
`docker system prune`	Clean up unused resources

1. docker run — Create and Start a Container

Terminalbash

# Basic run
docker run nginx

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

# Run with a name
docker run -d --name my-web nginx

# Run with port mapping
docker run -d -p 8080:80 nginx

# Run interactively
docker run -it ubuntu bash

# Run and auto-remove on exit
docker run --rm alpine echo "hello"

# Run with environment variables
docker run -e MY_VAR=value ubuntu env

# Run with a volume
docker run -v /host/path:/container/path nginx

Common `docker run` flags

Flag	What it does
`-d`	Detached — run in background
`-it`	Interactive — attach a terminal
`-p host:container`	Publish a port
`-e KEY=VALUE`	Set environment variable
`-v host:container`	Mount a volume
`--name NAME`	Give the container a name
`--rm`	Auto-remove on exit
`-m 512m`	Memory limit
`--cpus 1.5`	CPU limit

2. docker ps — List Containers

Terminalbash

# Running containers only
docker ps

# All containers (including stopped)
docker ps -a

# Only show IDs (useful for scripts)
docker ps -q

# Show last created container
docker ps -l

# Filter by name
docker ps -f name=my-web

Output format

Outputbash

CONTAINER ID   IMAGE    COMMAND                  CREATED         STATUS         PORTS                  NAMES
abc123def456   nginx    "/docker-entrypoint.…"   3 minutes ago   Up 3 minutes   0.0.0.0:8080->80/tcp   my-web

3. docker images — List Local Images

Terminalbash

# List all images
docker images

# Same thing (alias)
docker image ls

# Show only IDs
docker images -q

# Filter by name
docker images nginx

4. docker pull — Download an Image

Terminalbash

# Pull latest
docker pull ubuntu

# Pull specific version
docker pull ubuntu:22.04

# Pull from a specific registry
docker pull ghcr.io/owner/repo:tag

# Pull all tags
docker pull -a alpine

5. docker exec — Run Commands in a Running Container

Very useful

If a container is running and you want to run a command inside it (without stopping it), use docker exec.

Terminalbash

# Open a shell inside a running container
docker exec -it my-web bash

# Run a single command
docker exec my-web ls /etc

# Run as a specific user
docker exec -u root my-web whoami

6. docker logs — View Container Logs

Terminalbash

# View all logs
docker logs my-web

# Follow logs (like tail -f)
docker logs -f my-web

# Last 50 lines
docker logs --tail 50 my-web

# Logs since a timestamp
docker logs --since 2026-08-23T09:00:00 my-web

# With timestamps
docker logs -t my-web

7. docker stop / start / restart

Terminalbash

# Stop a container (graceful, 10s timeout)
docker stop my-web

# Force kill immediately
docker kill my-web

# Start a stopped container
docker start my-web

# Restart a running container
docker restart my-web

8. docker rm / rmi — Remove Containers and Images

Terminalbash

# Remove a stopped container
docker rm my-web

# Force remove a running container
docker rm -f my-web

# Remove an image
docker rmi nginx

# Remove all stopped containers
docker container prune

# Remove all unused images
docker image prune -a

9. docker build — Build an Image from Dockerfile

Terminalbash

# Build from Dockerfile in current directory
docker build -t myapp:1.0 .

# Build with a specific Dockerfile
docker build -f Dockerfile.prod -t myapp:prod .

# Build without cache
docker build --no-cache -t myapp:1.0 .

10. docker inspect — Get Detailed Info

Terminalbash

# Full JSON output
docker inspect my-web

# Get just the IP address
docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' my-web

# Get the entrypoint
docker inspect -f '{{.Config.Entrypoint}}' my-web

11. docker stats — Live Resource Usage

Terminalbash

# Live stats for all running containers
docker stats

# Stats for a specific container
docker stats my-web

# One snapshot (no live update)
docker stats --no-stream

Output:

Outputbash

CONTAINER ID   NAME      CPU %   MEM USAGE / LIMIT   MEM %    NET I/O         BLOCK I/O
abc123def456   my-web    0.50%   25MiB / 512MiB      4.89%    5.2kB / 8.1kB   0B / 0B

12. docker system prune — Clean Up Everything

This removes data

These commands delete stopped containers, unused images, and unused networks. Use with care.

Terminalbash

# Remove stopped containers, unused networks, dangling images
docker system prune

# Also remove all unused images (not referenced by containers)
docker system prune -a

# Also remove volumes (BE CAREFUL — deletes data!)
docker system prune -a --volumes

Command Patterns You'll Use Constantly

Pattern 1: "Run this one-off command"

Patternbash

docker run --rm alpine echo "hello"

Pattern 2: "Get a shell in that container"

Patternbash

docker exec -it <container-name> bash

Pattern 3: "What's using my disk?"

Patternbash

docker system df

Pattern 4: "Clean everything and start fresh"

Patternbash

docker stop $(docker ps -q) && docker system prune -a --volumes

Pattern 5: "Stop all running containers"

Patternbash

docker stop $(docker ps -q)

Cleaning Up — The Full Workflow

docker ps -a — see all containers

docker stop $(docker ps -q) — stop all running containers

docker container prune — remove stopped containers

docker image prune -a — remove unused images

docker volume prune — remove unused volumes (⚠️ deletes data!)

docker network prune — remove unused networks

docker system df — see disk usage (confirm cleanup worked)

Common Mistakes

Avoid these

Using docker rm on a running container. It fails. Stop first, or use -f.
Forgetting -it with docker exec. Without -it, you get output but no interactive shell.
Not cleaning up. Stopped containers and unused images pile up. Run docker system prune regularly.
Using docker system prune -a --volumes carelessly. This deletes all unused volumes — including database data. Only run this when you're sure.
Confusing docker rm (containers) and docker rmi (images). rm = remove container, rmi = remove image.

Practical Exercise (15 minutes)

Run docker run -d -p 8080:80 --name web1 nginx

Run docker ps — see web1 running

Run docker exec -it web1 bash — get a shell

Inside the container, run apt-get update && apt-get install -y curl

Run curl http://localhost — see the nginx HTML

Type exit

Run docker logs web1 — see the access logs

Run docker stats --no-stream — see resource usage

Run docker stop web1 && docker rm web1 — clean up

Run docker system prune -f — remove unused resources

Mini Challenge

Create a "cleanup script" — a single command that stops all running containers, removes all stopped containers, and removes all unused images. Test it carefully. (Hint: use $(docker ps -q) for container IDs.)

Key Takeaways

docker run creates and starts containers. Use -d, -it, -p, -v, -e, --name.
docker ps shows running containers; docker ps -a shows all.
docker exec -it <name> bash gets a shell in a running container.
docker logs -f <name> follows logs in real time.
docker system prune cleans up; add -a for all images, --volumes for data (careful!).
docker stats shows live resource usage; docker inspect shows detailed JSON.

Previously: Lesson 06 ran your first containers.
Today: You learned the 15 essential Docker CLI commands and their flags.
Next: Lesson 08 goes deeper into the container lifecycle.

FAQ

What's the difference between docker stop and docker kill?

docker stop sends SIGTERM, waits 10 seconds for graceful shutdown, then sends SIGKILL. docker kill sends SIGKILL immediately. Use stop for graceful shutdown; kill only when the container is stuck.

How do I see what's inside a container's filesystem?

Use docker exec -it <name> ls / for a quick look, or docker exec -it <name> bash for a full shell. For a stopped container, use docker cp <name>:/path ./local-path to copy files out.

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What You'll Learn

The Commands You'll Use Every Day

1. docker run — Create and Start a Container

Common docker run flags

2. docker ps — List Containers

Output format

3. docker images — List Local Images

4. docker pull — Download an Image

5. docker exec — Run Commands in a Running Container

6. docker logs — View Container Logs

7. docker stop / start / restart

8. docker rm / rmi — Remove Containers and Images

9. docker build — Build an Image from Dockerfile

10. docker inspect — Get Detailed Info

11. docker stats — Live Resource Usage

12. docker system prune — Clean Up Everything

Command Patterns You'll Use Constantly

Pattern 1: "Run this one-off command"

Pattern 2: "Get a shell in that container"

Pattern 3: "What's using my disk?"

Pattern 4: "Clean everything and start fresh"

Pattern 5: "Stop all running containers"

Cleaning Up — The Full Workflow

Common Mistakes

Practical Exercise (15 minutes)

Mini Challenge

Key Takeaways

FAQ

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Common `docker run` flags