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docker logs

Learn to view container output with docker logs.

docker logs

Whatever a container's main process writes to standard output (stdout) and standard error (stderr), Docker stores. docker logs shows these records; it works even if the container has stopped:

$ docker logs web
/docker-entrypoint.sh: Configuration complete; ready for start up
172.17.0.1 - - [03/Nov/2026:10:12:01 +0000] "GET / HTTP/1.1" 200 615

That is why applications inside containers should write their logs to stdout, not to a file.

Following and filtering

In long logs, three options make your job easier:

docker logs -f web            # follow live (like tail -f), exit with Ctrl+C
docker logs --tail 20 web     # last 20 lines
docker logs --since 10m web   # last 10 minutes
docker logs -t web            # timestamp on every line

They can be combined: docker logs -f --tail 50 web shows the last 50 lines and switches to live watching.

Practice Inspect the logs

Write two commands: show the last 20 lines of the web container with timestamps; then follow its logs from the last 5 minutes live.

Starter code

terminal
# buraya yaz

Sample solution

terminal
docker logs -t --tail 20 web
docker logs -f --since 5m web

Expected output

2026-11-03T10:12:01.512Z 172.17.0.1 - - "GET / HTTP/1.1" 200 615

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What happens if an application writes its logs to /var/log/app.log inside the container?

  • The container doesn't start
  • docker logs doesn't show those records Correct answer
  • docker logs reads the file automatically
  • The file is copied to the host

Explanation: docker logs captures only stdout and stderr.

2 Follow the logs live.

Question 
docker logs ____ web
Answer 
docker logs -f web

Explanation: -f (follow) prints new lines as they arrive.

3 Match the flags.

Term Meaning
-f Follow live
--tail 20 Last 20 lines
--since 10m Last 10 minutes
-t Timestamps

All lessons in Beginner

1 What is Docker?

  1. What is Docker?
  2. Containers and virtual machines
  3. Images and containers
  4. Docker architecture
  5. Use cases
  6. Summary - What is Docker

2 Installation and first commands

  1. Installing Docker
  2. docker version
  3. docker info
  4. The hello-world container
  5. Docker Desktop
  6. Summary - Installation

3 First container

  1. docker run basics
  2. Running in the background
  3. docker ps
  4. docker stop and rm
  5. docker logs
  6. Summary - First container

4 Dockerfile basics

  1. What is a Dockerfile?
  2. The FROM instruction
  3. The RUN instruction
  4. COPY and ADD
  5. CMD and ENTRYPOINT
  6. Summary - Dockerfile

5 Build and images

  1. docker build
  2. Tagging images
  3. Build context
  4. Layers and cache
  5. .dockerignore
  6. Summary - Build

6 docker run options

  1. Interactive mode
  2. Naming containers
  3. Restart policy
  4. Working directory
  5. Switching users
  6. Summary - docker run

7 Image management

  1. docker images
  2. docker rmi
  3. docker pull
  4. docker push
  5. docker tag
  6. Summary - Image management

8 Port mapping

  1. The port concept
  2. The -p flag
  3. Multiple ports
  4. Random ports
  5. IP binding
  6. Summary - Port mapping

9 Volumes and data

  1. Data persistence
  2. Named volumes
  3. The -v flag
  4. Bind mounts
  5. Volume management
  6. Summary - Volumes

10 Environment variables

  1. The -e flag
  2. The ENV instruction
  3. The ARG instruction
  4. env-file
  5. The WORKDIR instruction
  6. Summary - Environment

11 Project: docker-compose

  1. Compose design
  2. Service definition
  3. Database service
  4. Volume and network
  5. Putting it together - compose

12 Docker Hub and registry

  1. What is Docker Hub?
  2. docker login
  3. Searching images
  4. Official images
  5. Private registry
  6. Summary - Registry

13 Network basics

  1. Network drivers
  2. docker network ls
  3. Bridge network
  4. Container connectivity
  5. Publishing ports
  6. Summary - Network

14 Beginner final

  1. Challenge - Dockerfile
  2. Challenge - Build and run
  3. Challenge - Volume
  4. Challenge - Compose
  5. Challenge - Beginner project