dotnet-installer/src/dotnet/CommonOptions.cs

using System.IO;
using Microsoft.DotNet.Cli.CommandLine;
using Microsoft.DotNet.Tools.Common;

namespace Microsoft.DotNet.Cli
{
    internal static class CommonOptions
    {
        public static Option HelpOption() =>
            Create.Option(
                "-h|--help",
                "Show help information",
                Accept.NoArguments,
                materialize: o => o.Option.Command().HelpView());

        public static Option VerbosityOption() =>
            Create.Option(
                "-v|--verbosity",
                "Set the verbosity level of the command. Allowed values are q[uiet],<2C>m[inimal],<2C>n[ormal],<2C>d[etailed], and<6E>diag[nostic]",
                Accept.AnyOneOf("q", "quiet",
                          "m", "minimal",
                          "n", "normal",
                          "d", "detailed")
                      .ForwardAs("/verbosity:{0}"));

        public static ArgumentsRule DefaultToCurrentDirectory(this ArgumentsRule rule) =>
            rule.With(defaultValue: () => PathUtility.EnsureTrailingSlash(Directory.GetCurrentDirectory()));
    }
}