CommandLine.NetCore 1.0.8

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dotnet add package CommandLine.NetCore --version 1.0.8                
NuGet\Install-Package CommandLine.NetCore -Version 1.0.8                
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="CommandLine.NetCore" Version="1.0.8" />                
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add CommandLine.NetCore --version 1.0.8                
#r "nuget: CommandLine.NetCore, 1.0.8"                
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install CommandLine.NetCore as a Cake Addin
#addin nuget:?package=CommandLine.NetCore&version=1.0.8

// Install CommandLine.NetCore as a Cake Tool
#tool nuget:?package=CommandLine.NetCore&version=1.0.8                

CommandLine.NetCore CommandLine.NetCore

CommandLine.NetCore library provides support to handle command line arguments (parse, validate, command pattern) for .Net Core console applications with ANSI VT support (cursor,colors,screen size) for multi-plateform (windows, linux, osx, arm) console applications using C# and .NET Core 6

licence mit This project is licensed under the terms of the MIT license:
last commit version


The library provides functionalities needed to build console applications running in a terminal (WSL/WSL2, cmd.exe, ConEmu, bash, ...) with text interface. That includes:

  • parsing command line arguments

  • command pattern helps implementing commands binded to methods from command line in a simple and regular way

  • multi-language commands help configuration files

  • automatic help command

  • can compile a .exe for a a single command command, showing only the help for a specific command, or for several commands, showing a help for all commands as a shell would do

  • compatible with AnsiVtConsole.NetCore :

    • a text printer engine that supports print directives (markup) allowing to manage console functionalities from text itself, as html would do but with a simplest syntax (that can be configured). That makes possible colored outputs, cursor control, text scrolling and also dynamic C# execution (scripting), based on System.Console and ANSI VT100 / VT52 (VT100 type Fp or 3Fp, Fs, CSI, SGR)

    • A Ansi Parser that can identify/remove escape sequences in a text

    • The console output can be controlled by:

      • tokens in a string (print directives)
      • as string shortcuts (dynamic ansi vt strings)
      • throught API methods


1. Running the command line

download the nuget from command line or add it from Visual Studio

@rem version 1.0.8 or any new one
dotnet add package CommandLine.NetCore --version 1.0.8


When installing the package, the following files are copied into your project:

  • Config/appSettings.core.json
  • assets/ascii-icon.png

you can delete any of these files EXCEPT Config/appSettings.core.json wich is mandatory since it contains the CommandLine.NetCore parser root configuration

these files are set as Content and are copied to output folder on build

link to the library in your console application main class (example: Program.cs):

using CommandLine.NetCore;

from your main method, transfer control to the library CommandLine.NetCore :

/// <summary>
/// command line input
/// <para>commandName ( option (optionValue)* | parameter )* globalOption*</para>
/// </summary>
/// <param name="args">arguments</param>
/// <returns>status code</returns>
public static int Main(string[] args)
    => new CommandLineInterfaceBuilder()

That leads to the loading of any command line components like global arguments, commands and help settings from both the library core and your own console app and parsing of the declared syntaxes and eventualy execution of the method corresponding to the matching syntax.

2. Testing the integrated help command:

Any console application built with the library ComandLine.NetCore implements by default a command named help that dump any available help about commands that are implemented in the software that uses the library and in the library itself.

As an example, you can build the example application console, provided in the project CommandLine.NetCore.Example, Just execute in your favorite shell this command (available in the folder bin/Release/net6.0):

./CommandLine.NetCore.Example.exe help

To get the help for a particular command, the syntax is help {commandName}. In this example you get help about the command help:

./CommandLine.NetCore.Example.exe help help

3. Configuring the library and a console application built with it

The library settings provides the description of the application and of the commands, and also the translation of texts. You should override these settings according to your needs.

Every settings are pushed throught IHostBuilder.ConfigureAppConfiguration. Settings are looked up by this way, in the specified order:

provided by the library CommandLine.NetCore:

  • appSettings.core.json : this file contains the settings needed by the core functionalities of the library: decription of the library, texts and description of the integrated command, in the default language (en-us)

  • appSettings.core.{culture}.json : same as above, any of these files provides translations for the culture specified by the tag {culture} according to available cultures specified in Microsoft.. The settings file that matches the current platform culture is loaded if it exists.

provided by your application;

  • appSettings.json : dscription of the commands provided by your application, the texts, and any settings in the default language (en-us)

  • appSettings.{culture}.json : same as above for the translations of the culture specified by the tag {culture}

The settings must conform with the following conventions:

Informations about application

"App": {
    "Title": "CommandLine.NetCore",
    "ReleaseDate": "10/12/2022"


"Texts": {
    "{TextId}": "Text"

Description of the commands

"Commands": {
    "{CommandName}": {
        "Description": "short description of the command",
        "Syntax": {
            "{Syntax 1}" : "Description of the functionality provided by the syntax 1",
            "{Syntax n}" : "Description of the functionality provided by the syntax n",
        "Options": {
            "{Option 1}" : "Description of the command option 1",
            "{Option n}" : "Description of the command option n",

example of the command help :

"Commands": {
    "help": {
      "Description": "output a of list commands and global arguments or output help about a command",
      "Syntax": {
        "": "list all commands",
        "commandName": "help about the command with name commandName"
      "Options": {
        "-v": "enable verbose: add details to normal output",
        "--info" : "output additional informations about the command line context"

These settings are describing the following syntaxes for the command help:

; help for a command
help {commandName} [-v] [--info]
; global help (all commands)
help [-v] [--info]

Command options are optionals and are available for any syntax of the command (here -v and --info). They can appears from the position they are declared in the command syntax

Description of the global arguments

"GlobalOptions": {
    "{ArgumentName}": {
        "{Syntax}" : "Description of the functionality provided by the argument syntax"

Global arguments are optional and availables for any command. They must appear from the end of the command arguments

example of the global argument s :

"GlobalOptions": {
    "s": {
        "-s" : "turn off any output (silent mode)"

by convention (POSIX), single letter arguments are prefixed by -, whereas arguments with several letters are prefixed by --

4. Implementing a command

A command specification and implementation is defined in a class that inherits from CommandLine.NetCore.Services.CmdLine.Commands.Command.

  • the name of the command is kebab case from the name of the class (in this case GetInfo declares the get-info command)
  • the command class msut have a constructor with parameter Dependencies. These classes are instantiated by the dependency injector, thus any registered dependency can be added as a constructor parameter
  • the command class must implements the method:
    CommandResult Execute(ArgSet args)
  • the method Execute declares the syntaxes of the command and the related implementations
  • the method For declares a command syntax:
    For(params Arg[] syntax)
  • the list of arguments are specifing the command syntax
    • an Arg is either an option or a parameter. Their grammar is defined as this:
      • Option ::= [-|--]{optionName}[value0..valuen]

        • options can be expected or optionnal
        • can have from 0 to n values of a type T, where T can be any scalar type, a collection of scalar types (with , as separator) or an Enum
        • an option can be defined with values, values are always expected
        • Opt("x") builds the option x with no expected value: -x
        • by convention (posix), if the length of the name of the option is greater than 1, the prefix becomes: --. For instance, Opt("xy") defines the syntax: --xy
        • Opt("x",true) builds the option x wich is optional in the syntax
        • Opt<T>("value") builds the option value having one expected value that must be convertible to type T. For instance, Opt<int>("value") defines an option that expect an int, like in syntax: --value 123
      • Parameter ::= parameterValue?

        • parameters are always expected
        • have a value of a type T, where T can be any scalar type, a collection of scalar types (with , as separator) or an Enum
        • if a parameter if defined with a value, it is an expected word in the syntax
        • if a parameter is defined without a value, a value is expected in the syntax
        • Param() builds a parameter that expect a value of type string like in syntax: iamastring
        • Param<T>() builds a parameter that expect a value that must be convertible to type T. For instance, Param<int>() builds a parameter that expect a value of type int, like in syntax: 123
        • Param("color") builds a parameter that is expected and being the syntax: color
  • the method Do chained to a For indicates the method that must be executed if the syntax match the command line args:

    // with no parameter and void result delegate
    Do(Action @delegate)
    // with no parameter and void result delegate
    Do(Func<OperationResult> @delegate)
    // with parameter operation context and void delegate
    Do(Action<OperationContext> @delegate)
    // with parameter operation context and OperationResult result delegate
    Do(Func<OperationContext, OperationResult> @delegate)
    // takes a method in a lambda unary call expression: () => methodName, takes a called method with no parameter, takes a called method with a default command result (code ok, result null).
    // Allows to map command arguments to method parameters and operation context
    Do(LambdaExpression expression)

    the lambda expression in the method style Do(LambdaExpression expression) can have these profiles:

    // no parameter and no result
    void MyOperation()
    // explicit mapping of argument and no result
    void MyOperation([MapArg(1) Param<string> arg0,[MapArg(5)] Opt<bool> arg1)
    // implicit mapping of arguments and no result
    // expected arguments (arguments having expected valie(s)) are mapped according to their declaring order
    void MyOperation(Param<string> arg0,Opt<bool> arg1)
    // can also have an auto-mapped parameter to the operation context:
    // a parameter of type OperationContext can be placed anywhere in the parameters list
    void MyOperation(...,OperationContext context,..)
  • methods For can be chained

  • the method Options can be chained to a For. This method allows to declare the command options:

    Options(params IOpt[] options)
  • the method With launch the command executing process. First command line parsing, then syntax matching, then operation dispatch:

    With(ArgSet args)

Exemple of the command help defined in CommandLine.NetCore.Commands.CmdLine:

// command syntax: help [commandName] [-v] [--info]
internal sealed class Help : Command
    protected override CommandResult Execute(ArgSet args) =>

        // syntax: help
            .Do(() => DumpHelpForAllCommands)

        // syntax: help {commandName}
            .Do(() => DumpCommandHelp)

        // any syntax accepts -v and/or --info
        .Options(Opt("v"), Opt("info"))

        // parse and run

    private void DumpCommandHelp(Param commandName, Opt v, Opt info)
        // ...

    private void DumpHelpForAllCommands(Opt v, Opt info)
        // ...

Exemple of the command get-info defined in CommandLine.NetCore.Example.Commands.GetInfo:

// syntax: get-info (env -l) | (env {varName}) | console | system | --all
internal sealed class GetInfo : Command
    protected override CommandResult Execute(ArgSet args) =>

        // syntax: get-info env -l

        // syntax: get-info env {varName}
                .Do(() => DumpEnvVar)

        // syntax: get-info console

        // syntax: get-info system

        // syntax: get-info --all

        // parse and run

    private void DumpEnvVar(Param envVarName)
        // ...

Versions history

1.0.8 - 01/14/2023

  • add single command mode to produce an executable for only one command and eventually without the global help
  • change editor config and code cleanup
  • packages update

1.0.7 - 01/13/2023

  • add global option --no-color that turn off ansi/vt outputs
  • fix auto syntax -h was not passing global arguments
  • new RunCommand in current host
  • improve help output
  • embed symbols and sources

1.0.6 - 01/11/2023

  • fix MAJOR bug in command options parsing. Were not recongnized correctly
  • AppHostBuilder moved to namespace CommandLine.NetCore.Services.AppHost
  • fix auto command -h (Command.RunCommand) didn't call back configure and build delegates
  • fix support of -v and --info in -h auto syntax
  • doc update

1.0.5 - 01/05/2023

  • fix nupkg: adding the package to a project now deploy files Config/appSettings.core.json,,, assets/ascii-icon.png in your project. These files are configured as 'Content' and are deployed in the bin folder. You can remove any of these files EXCEPT Config/appSettings.core.json wich is mandatory since it contains the CommandLine.NetCore parser root configuration
  • fix doc

1.0.4 - 01/04/2023

  • fix nupkg

1.0.3 - 01/04/2023

  • fix nupkg

1.0.2 - 01/04/2023

  • fix doc

1.0.1 - 01/04/2023

  • add CommandContext to lambda operations method
  • add support of abstract classes that inherits from command
  • rename OperationContext by CommandContext
  • fix bug command options were always set in delegate for -h

1.0.0 - 03/01/2023

  • init

Product Compatible and additional computed target framework versions.
.NET net6.0 is compatible.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
Compatible target framework(s)
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1.0.8 - 01/14/2023
- add single command mode to produce an executable for only one command and eventually without the global help
- change editor config and code cleanup
- packages update