What this snippet does
EXPOSE documents the port the service listens on; it does not publish it to the host.
Expected output
Successfully built 9c1f4b7a2d3e
Why practise typing this
Typing dockerfile basics code builds muscle memory for the symbols and indentation Docker uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More Docker practice
- Minimal imageDockerfile Basics · beginner
- Untagged base imageDockerfile Basics · beginner
- Running a build commandDockerfile Basics · beginner
- Split RUN loses the cacheDockerfile Basics · intermediate
- Setting the working directoryDockerfile Basics · beginner
- cd does not persistDockerfile Basics · beginner