How do I make a comment in a Dockerfile?

docker dockerfile
kpie picture kpie · Apr 19, 2016 · Viewed 157.2k times · Source

I am writing a Dockerfile. Is there a way to make comments in this file?

Does Docker have a comment option that takes the rest of a line and ignores it?

Answer

Ranjeet picture Ranjeet · Apr 19, 2016

You can use # at the beginning of a line to start a comment (whitespaces before # are allowed):

# do some stuff
RUN apt-get update \
    # install some packages
    apt-get install -y cron

#'s in the middle of a string are passed to the command itself, e.g.:

RUN echo 'we are running some # of cool things'

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