Meziantou.Framework.CommandLine 4.0.3

Meziantou.Framework.CommandLine

A .NET library that provides utilities for working with command-line arguments, including parsing, building/escaping arguments, and creating interactive console prompts.

Features

• CommandLineParser: Parse command-line arguments with support for named and positional arguments
• CommandLineBuilder: Properly escape and quote arguments for Windows command-line and cmd.exe
• Prompt: Create interactive yes/no prompts in console applications

Usage

The types are in the Meziantou.Framework namespace.

CommandLineParser

Parse command-line arguments with support for named arguments (with / or - prefix) and positional arguments.

// Parse current process arguments
var currentParser = CommandLineParser.Current;
Assert.NotNull(currentParser);

// Or parse custom arguments
var parser = new CommandLineParser();
parser.Parse(["/name=John", "/verbose", "input.txt"]);

// Check if an argument exists
Assert.True(parser.HasArgument("verbose"));

// Get named argument value
Assert.Equal("John", parser.GetArgument("name"));

// Get positional argument (the index in the array of arguments)
Assert.Equal("input.txt", parser.GetArgument(2));

// Check if help was requested: detects -?, /?, -help, /help, --help
Assert.False(parser.HelpRequested);

Supported argument formats:

• Named with equals: /name=value or -name=value
• Named with colon: /name:value or -name:value
• Named without value: /verbose or -verbose
• Positional: any argument without prefix

CommandLineBuilder

Properly escape and quote arguments for safe command-line execution on Windows.

// Quote a single argument for standard Windows applications
var arg = CommandLineBuilder.WindowsQuotedArgument(@"path with spaces\file.txt");
Assert.Equal(@"""path with spaces\file.txt""", arg);

// Quote multiple arguments
var args = CommandLineBuilder.WindowsQuotedArguments("arg1", "path with spaces", "normal");
Assert.Equal(@"arg1 ""path with spaces"" normal", args);

// Quote for cmd.exe (handles special characters like &, |, ^, etc.)
var cmdArg = CommandLineBuilder.WindowsCmdArgument(@"malicious argument"" & whoami");
Assert.Equal(@"^""malicious argument\^"" ^& whoami^""", cmdArg);

var cmdArgs = CommandLineBuilder.WindowsCmdArguments("echo", "Hello & Goodbye");
Assert.Equal(@"echo ^""Hello ^& Goodbye^""", cmdArgs);

Why use CommandLineBuilder?

• Handles spaces, quotes, and backslashes correctly
• Prevents command injection attacks
• WindowsCmdArgument handles cmd.exe special characters: (, ), %, !, ^, ", <, >, &, |
• Based on Microsoft's article: Everyone quotes command line arguments the wrong way

Prompt

Create interactive yes/no prompts in console applications.

// Simple yes/no prompt with default value
var proceed = Prompt.YesNo("Do you want to continue?", defaultValue: true);
// Displays: Do you want to continue? [Y/n]
// User can press Enter to use default (true)

// Without default value
var confirm = Prompt.YesNo("Are you sure?", defaultValue: null);
// Displays: Are you sure? [y/n]
// User must enter y or n

// Custom yes/no labels
var delete = Prompt.YesNo("Delete file?", "Yes", "No", defaultValue: false);
// Displays: Delete file? [y/N]

// Prompts are case-insensitive and loop until valid input
var result = Prompt.YesNo("Enable feature?", defaultValue: true);
if (result)
{
    Console.WriteLine("Feature enabled!");
}