GreetCommand.cs

public class GreetCommand : Command
{
    private readonly GreetOptions options;

    public GreetCommand(GreetOptions options)
       : base("greet", "Says a greeting to the specified person.")
    {
        var name = new Option<string>("--name")
        {
            Name = "name",
            Description = "The name of the person to greet.",
            IsRequired = true
        };

        this.AddOption(name);

        this.Handler = CommandHandler.Create(
            (string name) => this.HandleCommand(name));
        this.options = options;
    }

    private int HandleCommand(string name)
    {
        try
        {
            Console.WriteLine($"{this.options.Greeting} {name}!");
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
            return 0;
        }

        return 1;
    }
}