While a package manager is not strictly necessary to get a dotnet core development environment up and running, it is extremely useful to have a single tool to update utilities rather than manually discovering the need to update and manually downloading them. It’s also useful to set up a consistent command line environment with Linux. You can use my step-by-step guide to set up MacPorts.
The intellisense engine for C# dotnet core projects in VSCode on Mac and Linux doesn’t use the dotnet core compilers, it uses mono. Microsoft has also provided ports of the SQL Server tools, sqlcmd and bcp
Visual Studio for Mac also depends on mono. If you have and use Visual Studio for Mac, you don’t need to install mono here. On the other hand, if you have an abandoned installation of Visual Studio for Mac you may want to remove it and start over. I have instructions for uninstalling Visual Studio for Mac at the end of this document.
MacPorts does not manage installs of the dotnet core SDKs, but Microsoft does offer scripts to install and uninstall. I created a simple shell script to combine these together to maintain the 2.1 and 3.1 LTS SDKs.