Question

This should be straightforward. I just need to simply exit my commandline c# program – no fancy stuff.

Should I use

Environment.Exit();

or

this.Close();

or something else?

Answer 1

Use return; in your Main method.
If you aren’t in the main method when you decide to exit the program, you need to return from the method that Main method currently executes.

Example:

void Main(...)
{
    DisplayAvailableCommands();
    ProcessCommands();
}

void ProcessCommands()
{
    while(true)
    {
        var command = ReadCommandFromConsole();
        switch(command)
        {
            case "help":
                DisplayHelp();
                break;
            case "exit":
                return;
        }
    }
}

This is not really an example of good overall design of a console application, but it illustrates the point.