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Docker · Directive

ONBUILD

ONBUILD saves a Dockerfile instruction for a later build. When another Dockerfile uses the image with FROM, Docker runs the saved instruction in that child build.

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Syntax

ONBUILD <INSTRUCTION>

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  • FROM
  • ADD
  • COPY
  • RUN
  • Dockerfile syntax
  • multi-stage builds

Source: Dockerfile reference. Checked 2026-11-03.