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by ianlevesque 4259 days ago
"Thus it seems that if you leave a file on disk between steps in your Dockerfile, the space will not be reclaimed when you delete the file."

This must be a bug? Why should it legitimately behave this way?
2 comments
cschneid 4259 days ago
From what I understand, docker caches the state of its world during each step. So you add a file, it caches, remove the file, it can't free that space from the layered filesystem. But if you create & remove in the same `RUN` command, it never gets persisted as a step, so doesn't take up space.
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enos_feedler 4259 days ago
I don't think its a bug. Its due to the layered filesystem architecture. Deleting a file in a later build step is not going to remove it from the previous layers. It just adds a new layer with meta-data saying the file has been removed.
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