.NET Core
Create Solution
This needs to be run in the directory where any project files you want to add are contained and run the following commands. Leave the “.sln” portion off the name of <my_solution> since it will be added automatically. Otherwise, you’ll end up with something like MySolution.sln.sln.
dotnet new sln --name <my_solution>
dotnet sln <my_solution> add <csproj_1> <csproj_2> ...