# dockerfile

* [dockerfile](#dockerfile)
  * [build from cmd](#build-from-cmd)

{% hint style="info" %}

> references:
>
> * [best practices for writing dockerfiles](https://docs.docker.com/develop/develop-images/dockerfile_best-practices/)
>   {% endhint %}

### dockerfile

{% hint style="info" %}

> references:
>
> * [JDK Script Friendly URLs](https://www.oracle.com/java/technologies/jdk-script-friendly-urls/)
>   {% endhint %}

```docker
ENV JAVA_PKG=https://download.oracle.com/java/17/latest/jdk-17_linux-x64_bin.tar.gz \
    JAVA_HOME=/usr/java/jdk-17

RUN set -eux; \
      JAVA_SHA256=$(curl "$JAVA_PKG".sha256) ; \
      curl --output /tmp/jdk.tgz "$JAVA_PKG" && \
      echo "$JAVA_SHA256 */tmp/jdk.tgz" | sha256sum -c; \
      mkdir -p "$JAVA_HOME"; \
      tar --extract --file /tmp/jdk.tgz --directory "$JAVA_HOME" --strip-components 1
```

#### [build from cmd](https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#build-an-image-using-a-dockerfile-from-stdin-without-sending-build-context)

```bash
$ docker build -t myimage:latest -<<EOF
FROM busybox
RUN echo "hello world"
EOF
```