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 add-apt-repository universe sudo apt-get update sudo apt-get install apt-transport-https sudo apt-get update sudo apt-get install dotnet-sdk-3.0
References
https://dotnet.microsoft.com/download/linux-package-manager/ubuntu18-04/sdk-current