Can you describe what is going on in `Dockerfile`

[kasir-barati]

Hello.

I need to create a custom nodejs image but with ubuntu image. Why? because of this issue, as you suggest there you use this image to resolve your issue and I guess the same thing can resolve my issue too. But IDK What packages I should install to build a nodejs image based on ubuntu:20.04.

This is what I did:

FROM ubuntu:20.04

RUN apt-get update && apt-get upgrade

RUN apt-get install -y apt-transport-https curl

RUN curl -fsSL https://deb.nodesource.com/setup_16.x | bash - \
    && apt-get install -y nodejs build-essential

WORKDIR /app

Do I missed anything?

I did not understand this RUN instruction and ttf-mscorefonts-installer.