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@@ -113,7 +113,7 @@ was no formal definition on as to which instructions handled environment
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replacement at the time. After 1.3 this behavior will be preserved and
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canonical.
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-Environment variables (declared with the `ENV` statement) can also be used in
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+Environment variables (declared with [the `ENV` statement](#env)) can also be used in
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certain instructions as variables to be interpreted by the `Dockerfile`. Escapes
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are also handled for including variable-like syntax into a statement literally.
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@@ -349,9 +349,8 @@ accessible from the host by default. To expose ports to the host, at runtime,
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ENV <key>=<value> ...
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The `ENV` instruction sets the environment variable `<key>` to the value
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-`<value>`. This value will be passed to all future
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-`RUN`, `ENTRYPOINT`, and `CMD` instructions. This is
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-functionally equivalent to prefixing the command with `<key>=<value>`
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+`<value>`. This value will be in the environment of all "descendent" `Dockerfile`
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+commands and can be [replaced inline](#environment-replacement) in many as well.
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The `ENV` instruction has two forms. The first form, `ENV <key> <value>`,
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will set a single variable to a value. The entire string after the first
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@@ -382,9 +381,10 @@ from the resulting image. You can view the values using `docker inspect`, and
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change them using `docker run --env <key>=<value>`.
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> **Note**:
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-> One example where this can cause unexpected consequences, is setting
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-> `ENV DEBIAN_FRONTEND noninteractive`. Which will persist when the container
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-> is run interactively; for example: `docker run -t -i image bash`
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+> Environment persistence can cause unexpected effects. For example,
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+> setting `ENV DEBIAN_FRONTEND noninteractive` may confuse apt-get
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+> users on a Debian-based image. To set a value for a single command, use
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+> `RUN <key>=<value> <command>`.
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## ADD
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Michael Crosby