Does not catch error in invalid RUN command

[prog1dev]

Issue details

Linter does not catch error in invalid RUN command

Steps to reproduce/test case

Dockerfile:

FROM ruby:2.1.5

RUN
 apt-get update && apt-get install -y libxslt-dev libxml2-dev screen rsync

Here is output of docker build command:

Error response from daemon: Dockerfile parse error line 4: unknown instruction: APT-GET

Here is output of dockerlint:

INFO: Dockerfile is OK.

Same goes for cases:

RUN apt-get update
 && apt-get install -y libxslt-dev libxml2-dev screen rsync

RUN apt-get update \\
 && apt-get install -y libxslt-dev libxml2-dev screen rsync

RUN apt-get update \
 && apt-get install -y
libxslt-dev libxml2-dev screen rsync

Environment

dockerlint: 0.3.1
node: v7.10.1
npm: 4.2.0
docker: 17.09.0-ce, build afdb6d4
OS: macOS Sierra 10.12.6

[rnagy]

Please test with commit 016185a

The issue is not with the RUN command but with the next line which
is an unknown instruction.