What is command-line-api?

dotnet/command-line-api — explained in plain English

Analysis updated 2026-07-03

★ 3,662C#Audience · developerComplexity · 2/5LicenseSetup · easy

Mindmap

mindmap
  root((command-line-api))
    What it does
      Argument parsing
      Input validation
      Help text generation
      Tab completion
    Key features
      Structured data binding
      dotnet-suggest integration
      Daily build packages
    Distribution
      NuGet packages
      MIT license
    Audience
      .NET developers
      CLI tool authors

mindmap root((command-line-api)) What it does Argument parsing Input validation Help text generation Tab completion Key features Structured data binding dotnet-suggest integration Daily build packages Distribution NuGet packages MIT license Audience .NET developers CLI tool authors

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What do people build with it?

USE CASE 1

Build a .NET command-line tool that accepts typed options and arguments without writing any argument-parsing code by hand.

USE CASE 2

Add automatic --help output and tab-completion to an existing .NET CLI application using dotnet-suggest.

USE CASE 3

Validate required command-line arguments and display user-friendly error messages when they are missing or invalid.

What is it built with?

C#.NETNuGet

How does it compare?

	dotnet/command-line-api	communitytoolkit/dotnet	oskardudycz/eventsourcing.netcore
Stars	3,662	3,671	3,672
Language	C#	C#	C#
Setup difficulty	easy	easy	moderate
Complexity	2/5	2/5	4/5
Audience	developer	developer	developer

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 30min

Install via NuGet, requires a .NET SDK already on your machine.

Use freely in any personal or commercial project, MIT license only requires keeping the copyright notice.

So what is it?

This repository holds the code for System.CommandLine, a set of official Microsoft libraries for building command-line applications in .NET. A command-line application is one that runs in a terminal and accepts options and arguments typed by the user, like most developer tools do. System.CommandLine handles the parts that would otherwise require a lot of repetitive code: parsing the text the user typed into structured data, binding those values to variables or objects in your program, validating that required arguments were provided, and generating help text automatically. It also includes tab-completion support through a companion tool called dotnet-suggest, which integrates with common shells so users can press Tab to see available options while typing a command. Both packages are distributed through NuGet, which is the standard package registry for .NET projects. The library is an official .NET Foundation project maintained by Microsoft, documented on Microsoft Learn, and licensed under the MIT open-source license. Daily build packages are also published for developers who want to test the latest unreleased changes.

Copy-paste prompts

Prompt 1

Using System.CommandLine, write a C# console app that accepts a --file path argument and an optional --verbose flag, then reads and prints the file contents.

Prompt 2

Show me how to bind System.CommandLine parsed options directly to a configuration object in .NET without manually extracting each value.

Prompt 3

How do I add tab-completion to my .NET CLI tool using dotnet-suggest so users can press Tab to see available subcommands and options?

Prompt 4

Write a System.CommandLine handler that validates a --count argument is between 1 and 100 and shows a specific error message when it is out of range.

Frequently asked questions