docopt.net is a parser for command-line arguments. It automatically derives the parsing logic from the help text of a program containing its command-line usage in docopt format. docopt is the formalization of conventions that have been used for decades in help messages and man pages for describing a program's interface. Below is an example of such a help text containing the usage for a hypothetical program called Naval Fate:

Naval Fate.

Usage:
  naval_fate.exe ship new <name>...
  naval_fate.exe ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.exe ship shoot <x> <y>
  naval_fate.exe mine (set|remove) <x> <y> [--moored | --drifting]
  naval_fate.exe (-h | --help)
  naval_fate.exe --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

The following C# example shows one basic way to use docopt.net:

#nullable enable

using System;
using DocoptNet;

const string usage = @"Naval Fate.

Usage:
  naval_fate.exe ship new <name>...
  naval_fate.exe ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.exe ship shoot <x> <y>
  naval_fate.exe mine (set|remove) <x> <y> [--moored | --drifting]
  naval_fate.exe (-h | --help)
  naval_fate.exe --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

";

var arguments = new Docopt().Apply(usage, args, version: "Naval Fate 2.0", exit: true)!;
foreach (var (key, value) in arguments)
    Console.WriteLine("{0} = {1}", key, value);

See the documentation for more examples and uses of the docopt.net API.

The documentation can be found online at https://docopt.github.io/docopt.net/.

Install the package in a .NET project using:

dotnet add package docopt.net

• © 2012-2014 Vladimir Keleshev [email protected]
• © 2013 Dinh Doan Van Bien [email protected]
• © 2021 Atif Aziz
• Portions © .NET Foundation and Contributors
• Portions © West Wind Technologies, 2008

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.