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# at the beginning of a line
# at middle of a line treated as 'command'
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# Use the # syntax for comments:
# My comment here
RUN echo 'we are running some cool things'
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# do some stuff
RUN apt-get update \
# install some packages
&& apt-get install -y cron
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# do some stuff
RUN apt-get update \
# install some packages
&& apt-get install -y cron
# at the start of a line to make a comment in a Dockerfile
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# do some stuff
RUN apt-get update \
# install some packages
&& apt-get install -y cron