Overview

This course focuses on building efficient, secure, and scalable Command-Line Interface (CLI) applications using C# and .NET. With CLI tools boosting flexibility and productivity, mastering these skills is essential for developers, system administrators, and DevOps professionals in today’s tech-driven world. Through this course, you will gain the hands-on skills needed to create powerful, modular CLI applications that are adaptable to various business needs. You will also learn how to implement best practices in performance optimization and security. What sets this course apart is its structured, step-by-step approach, combining theoretical insights with real-world projects and exercises. This balance ensures that you not only learn how to write the code but also understand the reasoning behind it, making your solutions both practical and scalable. This course is ideal for software developers, system administrators, and DevOps engineers with a basic understanding of programming, particularly those familiar with .NET and C#. It is designed to help you elevate your expertise in developing CLI tools that are secure, efficient, and adaptable for modern use cases.

Syllabus

Introduction to CLI Applications

In this section, we contrast CLI and GUI workflows, analyze speed, scripting, and resource benefits of text interfaces, evaluate selection criteria, and survey essential tools automating daily IT tasks.

Setting Up the Development Environment

Install Visual Studio Code, smart C Sharp helpers, the .NET SDK and configure Git to craft a dependable workspace for building and sharing command-line projects.

Basic Concepts of Console Applications in .NET

In this section, we scaffold a .NET console app with dotnet new, dissect Program.Main for argument parsing, and employ System.Console to validate input and output color-coded responses.

Command-Line Parsing

In this section, we learn to transform a plain console program into a full Command Line Interface, adding subcommands, parsed options, and automatic help and version feedback.

Input/Output and File Handling

In this section, we enhance our System. CommandLine bookmark CLI by validating option inputs, designating required or defaulted settings, and handling file parameters for reliable import, export, backup, and data sharing.

Error Handling and Logging

In this section, we learn to handle errors, write JavaScript Object Notation logs with Serilog, and shut down command line interface apps gracefully to capture every diagnostic detail.

Interactive CLI Applications

In this section, we explore how Spectre.Console enhances C# CLI apps by adding progress bars, adaptive prompts, FIGlet banners, and markup, turning simple utilities into interactive and engaging command line experiences.

Building Modular and Extensible CLI Applications

In this section, we create a code map of Bookmarkr, refactor commands with the Dependency Inversion Principle, and reorganize the project structure to build maintainable, testable, extensible CLI applications.

Working with External APIs and Services

In this section, we integrate external APIs in .NET using IHttpClientFactory, apply the Service Agent pattern to decouple and secure commands, and outline best practices for maintainable, extensible dependencies.

Testing CLI Applications

In this section, we examine why testing CLI applications matters, implement unit and integration tests with mocking, place them within the test pyramid, and schedule runs for secure, maintainable software.

Packaging and Deployment

In this section, we explore .NET 8 command line app packaging, automate deployments for Windows, macOS, and Linux, and implement semantic versioning to ensure each released build remains consistent and traceable.

Performance Optimization and Tuning

In this section, we instrument .NET applications, benchmark code with BenchmarkDotNet, identify CPU, memory and IO hotspots, and apply data-driven tuning techniques to maximize responsiveness.

Security Considerations for CLI Applications

In this section, we survey security domains impacting CLI tools and outline a posture assessment, then protect remote interactions by integrating Personal Access Token (PAT) authentication for safe data access.

Additional Resources and Libraries

In this section, we spot CLI scenarios needing specialized tools, choose libraries like Polly or MediatR, and map a learning plan from curated resources, ensuring maintainable, resilient, scalable command-line solutions.