Q: Quietly install MONO using dockerfile I am exploring docker. I want to create an image from Ubuntu with Mono installed on it. I created a Dockerfile as follows: - 
FROM ubuntu
MAINTAINER abc@xyz.com
ENV http_proxy "http://abc:xyz@myproxyserver:3128"
ENV https_proxy "https://abc:xyz@myproxyserver:3128"
RUN apt-get update
RUN apt-get install -y mono-complete
CMD["echo","Latest Ubuntu with MONO"]

On building the above Dockerfile it got stuck at the configuration of the timezone data. How can I pass the default timezone option in the dockerfile itself. 
Also one more question 
Can I create an image by merging two different images. I mean to say that we have one docker image for latest ubuntu and another docker image for latest mono. Can I combine both these images and have latest ubuntu with latest mono. 
Thanks

A: 1) Try this in your dockerfile:
ENV TZ=Europe/Rome
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

List of timezone is here:
https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
2) Personally I have never met such a requirement, so I am not sure these multi-stage builds fit for you. Take a look.
