.NET 3.1 running on Ubuntu 18.04

Dockerfile

FROM ubuntu:18.04

RUN apt-get update

RUN apt-get install wget -y
RUN wget https://packages.microsoft.com/config/debian/10/packages-microsoft-prod.deb -O packages-microsoft-prod.deb && \
    dpkg -i packages-microsoft-prod.deb

RUN apt-get install -y apt-transport-https && \
    apt-get update && \
    apt-get install -y dotnet-sdk-3.1 && \
    apt-get install -y aspnetcore-runtime-3.1

Build and run your container with the following commands:

cd <dir with Dockerfile>
docker build -t dotnet .
docker run -it --rm -v <your code dir here>:/code dotnet