Command Line Processing with Mono.GetOptions

Move over old style command line processing, if you're using Mono and C# - check out the Mono.GetOptions class to process command line options via .NET Attributes. ( Sample code lifted from a post by Jonathan Pryor to the mono.general mailing list.) The first step is to import the required assemblies in you code:

using System;
using System.Reflection;
using Mono.GetOptions;

Next we define some general meta-data for our application:

// Attributes visible in " --help"
[assembly: AssemblyTitle ("go.exe")]
[assembly: AssemblyVersion ("1.0.*")]
[assembly: AssemblyDescription ("Mono.GetOptions Sample Program")]
[assembly: AssemblyCopyright ("Public Domain")]

// This is text that goes after " [options]" in help output.
[assembly: Mono.UsageComplement ("")]

// Attributes visible in " -V"
[assembly: Mono.About("Insert About Text Here.")]
[assembly: Mono.Author ("Your name here")]

Almost there, now we define a class to hold our options.

class SampleOptions : Options
{
	// Long option is the variable name ("--file"), short option is -f
	[Option ("Write report to FILE", 'f')]
	public string file;

	// Long option is the variable name ("--quiet"), short option is -q
	[Option ("don't print status messages to stdout", 'q')]
	public bool quiet;

	// Long option is as specified ("--use-int"), no short option
	[Option ("Sample int option", "use-int")]
	public int use_int;

	public SampleOptions ()
	{
		base.ParsingMode = OptionsParsingMode.Both;
	}
}

And finally, write a program to use it:

class TestApp
{
	public static void Main (string[] args)
	{
		SampleOptions options = new SampleOptions ();
		options.ProcessArgs (args);

		Console.WriteLine ("Specified Program Options:");
		Console.WriteLine ("\t           file: {0}", options.file);
		Console.WriteLine ("\t          quiet: {0}", options.quiet);
		Console.WriteLine ("\t        use_int: {0}", options.use_int);

		Console.WriteLine ("Remaining Program Options:");
		foreach (string s in options.RemainingArguments) {
			Console.WriteLine ("\t{0}", s);
		}
	}
}

Oh yeh, and don't forget to compile it:

mcs -r:Mono.GetOptions go.cs

And voila, no muss. And what does it look like?

[mark@localhost mark]$ mono go.exe --help
go.exe  1.0.1573.25851 - Public Domain
Mono.GetOptions Sample Program
 
Usage: go [options]
Options:
  -f --file:PARAM                Write report to FILE
  -? --help                      Show this help list
  -q --quiet                     don't print status messages to stdout
     --usage                     Show usage syntax and exit
     --use-int:PARAM             Sample int option
     --verbosegetoptions         Show verbose parsing of options
  -V --version                   Display version and licensing information

[mark@localhost mark]$ mono go.exe --V
go.exe  1.0.1573.25851 - Public Domain
Mono.GetOptions Sample Program
 
Insert About Text Here.
 
Authors:
        Your name here
Specified Program Options:
                   file:
                  quiet: False
                use_int: 0
Remaining Program Options:

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