Docker and CI/CD · Middle · Question 4 of 75

Why does `RUN rm -rf /tmp/build` in a later layer not shrink the image?

1Docker restores deleted files when the container starts
✓Correct answer: Earlier layers still contain the files; deletion only hides them
3rm is not allowed in RUN instructions

Explanation

Layers are additive. Clean up in the same RUN that created the files, or use a multi-stage build so temporary files never reach the final image.

Further reading

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