Installing the .net sdk on a fresh install of Ubuntu Linux.

.Net is no longer a windows only programming framework. This is how to get things going on a fresh copy of linux.
Open a terminal window, then:

wget -q https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
sudo dpkg -i packages-microsoft-prod.deb
sudo apt-get update
sudo apt-get install apt-transport https
sudo apt-get install dotnet-sdk-3.1

The SDK allows you to build and run .net applications.

 
sudo apt-get install dotnet-runtime-3.1

The runtime merely allows you to run .net applications.

 
sudo apt-get install aspnetcore-runtime-3.1

Initially, I did the next commands through visual studio code, but it isn't necessary to use visual studio code to run them. Any terminal window will do.

dotnet new console
dotnet build 
dotnet publish

You will want to edit code eventually.

sudo snap install --classic code

Or just edit files in sublime

wget -qO - https://download.sublimetext.com/sublimehq-pub.gpg | sudo apt-key add -
echo "deb https://download.sublimetext.com/ apt/stable/" | sudo tee /etc/apt/sources.list.d/sublime-text.list
sudo apt-get update
sudo apt-get install sublime-text