Rewrote the ENTRYPOINT section in builder
Docker-DCO-1.1-Signed-off-by: James Turnbull (github: jamtur01)
@@ -374,41 +374,47 @@ The copy obeys the following rules:
ENTRYPOINT has two forms:
- `ENTRYPOINT ["executable", "param1", "param2"]`
- (like an *exec*, preferred form)
+ (like an *exec*, the preferred form)
- `ENTRYPOINT command param1 param2`
(as a *shell*)
-There can only be one `ENTRYPOINT` in a Dockerfile. If you have more than one
-`ENTRYPOINT`, then only the last one in the Dockerfile will have an effect.
+There can only be one `ENTRYPOINT` in a `Dockerfile`. If you have more
+than one `ENTRYPOINT`, then only the last one in the `Dockerfile` will
+have an effect.
-An `ENTRYPOINT` helps you to configure a container that you can run as an
-executable. That is, when you specify an `ENTRYPOINT`, then the whole container
-runs as if it was just that executable.
+An `ENTRYPOINT` helps you to configure a container that you can run as
+an executable. That is, when you specify an `ENTRYPOINT`, then the whole
+container runs as if it was just that executable.
-The `ENTRYPOINT` instruction adds an entry command that will **not** be
-overwritten when arguments are passed to `docker run`, unlike the behavior
-of `CMD`. This allows arguments to be passed to the entrypoint. i.e.
-`docker run <image> -d` will pass the "-d" argument to the ENTRYPOINT.
+Unlike the behavior of the `CMD` instruction, The `ENTRYPOINT`
+instruction adds an entry command that will **not** be overwritten when
+arguments are passed to `docker run`. This allows arguments to be passed
+to the entry point, i.e. `docker run <image> -d` will pass the `-d`
+argument to the entry point.
-You can specify parameters either in the ENTRYPOINT JSON array (as in
-"like an exec" above), or by using a CMD statement. Parameters in the
-ENTRYPOINT will not be overridden by the `docker run`
-arguments, but parameters specified via CMD will be overridden
-by `docker run` arguments.
+You can specify parameters either in the `ENTRYPOINT` JSON array (as in
+"like an exec" above), or by using a `CMD` instruction. Parameters in
+the `ENTRYPOINT` instruction will not be overridden by the `docker run`
+arguments, but parameters specified via a `CMD` instruction will be
+overridden by `docker run` arguments.
-Like a `CMD`, you can specify a plain string for the `ENTRYPOINT` and it will
-execute in `/bin/sh -c`:
+Like a `CMD`, you can specify a plain string for the `ENTRYPOINT` and it
+will execute in `/bin/sh -c`:
FROM ubuntu
- ENTRYPOINT wc -l -
+ ENTRYPOINT ls -l
-For example, that Dockerfile's image will *always* take STDIN as input
-("-") and print the number of lines ("-l"). If you wanted to make this
-optional but default, you could use a CMD:
+For example, that `Dockerfile`'s image will *always* take a directory as
+an input and return a directory listing. If you wanted to make this
+optional but default, you could use a `CMD` instruction:
FROM ubuntu
- CMD ["-l", "-"]
- ENTRYPOINT ["/usr/bin/wc"]
+ CMD ["-l"]
+ ENTRYPOINT ["/usr/bin/ls"]
+
+> **Note**:
+> It is preferable to use the JSON array format for specifying
+> `ENTRYPOINT` instructions.
## VOLUME
