Jessica Brown

Regular Expressions Tutorial Table of Contents

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Level 1 - The Foundations: Understanding JavaScript Basics

1. Introduction to JavaScript: What it is, how it works, and where it runs (browsers, Node.js). (part 1)

2. JavaScript Variables & Data Types: var, let, const, and primitive types (String, Number, Boolean, Undefined, Null, Symbol, BigInt). (part 2)

3. JavaScript Operators & Expressions: Arithmetic, comparison, logical, and assignment operators. (part 3)

4. JavaScript Conditional Statements: if, else, switch. (part 4)

5. JavaScript Loops & Iteration: for, while, do-while. (part 5)

6. JavaScript Functions: Function declarations, expressions, arrow functions, parameters, and return values. (part 6)

7. JavaScript Basic Debugging: console.log(), alert(), and browser developer tools. (part 7)

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Level 2 - Building Blocks: DOM Manipulation & Event Handling

1. Introduction to the DOM (Document Object Model): Understanding the structure of an HTML document. (part 8)

2. Selecting Elements in JavaScript: document.getElementById(), document.querySelector(), document.querySelectorAll(). (part 9)

3. Modifying Elements in JavaScript: Changing text, attributes, classes, and styles dynamically. (part 10)

4. JavaScript Event Handling: addEventListener(), event types (click, mouseover, keypress, etc.). (part 11)

5. JavaScript Forms & User Input: Handling form submissions, input validation, and preventing default behavior. (part 12)

6. JavaScript Timers & Intervals: setTimeout(), setInterval(). (part 13)

7. Intro to JavaScript Browser Storage: Local Storage, Session Storage, and Cookies. (part 14)

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Level 3 - Advancing Forward: Asynchronous JavaScript & APIs

1. Synchronous vs Asynchronous in JavaScript Programming: Understanding blocking vs non-blocking operations. (part 15)

2. JavaScript Callbacks & Callback Hell: Handling asynchronous execution with callback functions. (part 16)

3. Promises & .then() Chainingin with JavaScript: Writing cleaner async code with Promise objects. (part 17)

4. JavaScript Async/Await: Modern async handling, try-catch for error handling. (part 18)

5. Working with APIs in JavaScript: Fetching data using fetch() and handling JSON responses. (part 19)

6. AJAX & HTTP Requests, the JavaScript Way: Understanding HTTP methods (GET, POST, PUT, DELETE). (part 20)

7. JavaScript Error Handling & Debugging: try, catch, finally, throw. (part 21)

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Level 4 - Professional Development: Object-Oriented & Functional Programming

1. JavaScript Object Basics: Object literals, properties, methods. (part 22)

2. JavaScript Prototypes & Inheritance: Prototype chaining, Object.create(), and classes in ES6. (part 23)

3. Encapsulation & Private Methods in JavaScript: Using closures and ES6 classes to protect data. (part 24)

4. Functional Programming Principles Using JavaScript: Higher-Order Functions, Immutability, Closures & Lexical Scope, Array Methods, and Recursions (part 25)

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Level 5 - Expert Craftsmanship: Performance Optimization & Design Patterns

1. Code Performance & Optimization with JavaScript: Minimizing memory usage, reducing reflows, Event Loops, avoiding memory leaks (part 26)

2. Using JavaScript with Event Loop & Concurrency Model: How JavaScript handles tasks asynchronously. (part 27)

3. JavaScript’s Web Workers & Multithreading: Running JavaScript in parallel threads. (part 28)

4. Debouncing & Throttling with JavaScript: Optimizing performance-heavy event listeners. (part 29)

5. Design Patterns in JavaScript: Singleton, Factory, Observer, Module, and Proxy patterns (part 30)

6. JavaScript’s Best Security Practices: Avoiding XSS, CSRF, and SQL Injection, Sanitizing user inputs (part 31)

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Level 6 - The Extreme Zone: Meta-Programming & JavaScript Internals

1. Understanding the JavaScript Engine: How V8 and SpiderMonkey parse and execute JavaScript. (part 32)

2. Execution Context & Call Stack: Understanding how JavaScript executes code. (part 33)

3. Memory Management & Garbage Collection: How JavaScript handles memory allocation. (part 34)

4. Proxies & Reflect API: Intercepting and customizing fundamental operations. (part 35)

5. Symbol & WeakMap Usage: Advanced ways to manage object properties. (part 36)

6. WebAssembly (WASM): Running low-level compiled code in the browser. (part 37)

7. Building Your Own Framework: Understanding how libraries like React, Vue, or Angular work under the hood. (part 38)

8. Node.js & Backend JavaScript: Running JavaScript outside the browser. (part 39)

Welcome to this comprehensive guide on Regular Expressions (Regex). This tutorial is designed to equip you with the skills to craft powerful, time-saving regular expressions from scratch. We'll begin with foundational concepts, ensuring you can follow along even if you're new to the world of regex. However, this isn't just a basic guide; we'll delve deeper into how regex engines operate internally, giving you insights that will help you troubleshoot and optimize your patterns effectively.

What Are Regular Expressions? — Understanding the Basics

At its core, a regular expression is a pattern used to match sequences of text. The term originates from formal language theory, but for practical purposes, it refers to text-matching rules you can use across various applications and programming languages.

You'll often encounter abbreviations like regex or regexp. In this guide, we'll use "regex" as it flows naturally when pluralized as "regexes." Throughout this manual, regex patterns will be displayed within guillemets: «pattern». This notation clearly differentiates the regex from surrounding text or punctuation.

For example, the simple pattern «regex» is a valid regex that matches the literal text "regex." The term match refers to the segment of text that the regex engine identifies as conforming to the specified pattern. Matches will be highlighted using double quotation marks, such as "match."

A First Look at a Practical Regex Example

Let's consider a more complex pattern:

\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\b

This regex describes an email address pattern. Breaking it down:

• \b: Denotes a word boundary to ensure the match starts at a distinct word.

• [A-Z0-9._%+-]+: Matches one or more letters, digits, dots, underscores, percentage signs, plus signs, or hyphens.

• @: The literal at-sign.

• [A-Z0-9.-]+: Matches the domain name.

• .: A literal dot.

• [A-Z]{2,4}: Matches the top-level domain (TLD) consisting of 2 to 4 letters.

• \b: Ensures the match ends at a word boundary.

With this pattern, you can:

• Search text files to identify email addresses.

• Validate whether a given string resembles a legitimate email address format.

In this tutorial, we'll refer to the text being processed as a string. This term is commonly used by programmers to describe a sequence of characters. Strings will be denoted using regular double quotes, such as "example string."

Regex patterns can be applied to any data that a programming language or software application can access, making them an incredibly versatile tool in text processing and data validation tasks.

Next, we'll explore how to construct regex patterns step by step, starting from simple character matches to more advanced techniques like capturing groups and lookaheads. Let's dive in!

Securing a Linux server is an ongoing challenge. Every day, bad actors attempt to penetrate systems worldwide, using VPNs, IP spoofing, and other evasion tactics to obscure their origins. The source of an attack is often the least of your concerns, what matters most is implementing strong security measures to deter threats and protect your infrastructure. Hardening your servers not only makes them more resilient but also forces attackers to either move on or, ideally, abandon their efforts altogether.

This list of security recommendations is based on current best practices but should be implemented with caution. Always test configurations in a controlled environment before applying them to production servers. The examples and settings provided in each article are meant as guidelines and should be tailored to suit your specific setup. If you have any questions, sign up for an account and post them within the relevant article's discussion.

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Build a Hardened and Secure Linux Server (Level 1)

Protecting a Linux server involves more than just installing and configuring it. Servers are constantly at risk from threats like brute-force attacks, malware, and misconfigurations. This guide outlines crucial steps to enhance your server’s security, providing clear instructions and explanations for each measure. By following these steps, you can significantly improve your server’s resilience against potential threats!

1. Disable Root Login

2. Use Key-Based SSH Authentication

3. Enforce Strong Password Policies

4. Keep the System Updated

5. Configure a Firewall

6. Install and Configure Intrusion Detection (Fail2Ban)

7. Disable Unnecessary Services

8. Set Proper File Permissions

9. Enable Logging and Monitoring

10. Secure SSH Configuration
    

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Strengthen and Secure Your Linux Server (Level 2)

Securing a Linux server goes beyond basic installation and configuration, it requires proactive measures to mitigate risks such as brute-force attacks, malware infiltration, and system misconfigurations. This guide provides a structured approach to hardening your server, detailing essential security best practices with step-by-step instructions. By implementing these measures, you can fortify your server against vulnerabilities, ensuring a more robust and resilient security posture.

1. Harden Kernel Parameters

2. Schedule Regular Backups

3. Set Resource Limits

4. Perform a Security Scan with Lynis

5. Protect Against Malware

6. Enable Multi-Factor Authentication (MFA)

7. Implement Network Segmentation

8. Restrict sudo Access

9. Enforce AppArmor or SELinux

10. Set Up Port Knocking on Your Server

    
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Comprehensive Linux Server Hardening and Security Implementation (Level 3)

Achieving a truly secure Linux server requires a systematic and multi-layered approach, addressing both external threats and internal vulnerabilities. This guide delves into advanced security strategies, covering proactive defense mechanisms against brute-force attacks, malware infiltration, privilege escalation, and misconfigurations. It includes in-depth explanations of key hardening techniques, such as secure authentication methods, firewall optimization, intrusion detection systems, and least privilege enforcement. By following this guide, you will establish a fortified Linux environment with enhanced resilience against evolving cyber threats.

1. Limit Open Ports to Reduce Attack Surface

2. Use File Integrity Monitoring (FIM)

3. Implement Rate Limiting

4. Encrypt Sensitive Data

5. Set Up DNS Security Extensions (DNSSEC)

6. Use a Host-Based Intrusion Detection System (HIDS)

7. Regularly Rotate Encryption Keys and Credentials

8. Apply Principle of Least Privilege (PoLP)

9. Monitor for Configuration Drift

10. Set Up a Web Application Firewall (WAF)

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Advanced Linux Server Security and Threat Mitigation (Level 4)

At this level, securing a Linux server involves proactive measures that go beyond traditional hardening techniques. Advanced security configurations focus on mitigating sophisticated cyber threats, ensuring continuous monitoring, and implementing preventive controls. This guide explores methods such as sandboxing applications, enhancing authentication security, and conducting in-depth vulnerability assessments to fortify your server against emerging risks.

1. Implement Application Sandboxing

2. Configure Two-Factor Authentication (2FA) for SSH with Duo

3. Conduct Regular Vulnerability Scans

4. Implement Data Loss Prevention (DLP) Measures

5. Configure Advanced Auditing with Auditbeat and Filebeat

6. Set Up Remote Logging

7. Perform Regular Penetration Testing

8. Implement Access Control Lists (ACLs) for Fine-Grained Permissions

9. Use Bastion Hosts for Secure Server Access

10. Harden Database Access

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Enterprise-Grade Linux Security and Defense Mechanisms (Level 5)

As security threats become more sophisticated, enterprise-level hardening techniques ensure that a Linux server remains resilient against persistent and targeted attacks. This level focuses on securing sensitive data, enforcing strict access controls, and implementing deception technologies like honeypots to detect and analyze potential intrusions. By incorporating Zero-Trust principles and using Just-In-Time (JIT) access controls, organizations can minimize the risk of privilege escalation and unauthorized access.

1. Regularly Review Logs and Analyze Suspicious Activities

2. Encrypt Disk Partitions for Data Protection

3. Implement Zero-Trust Architecture Principles

4. Apply a Honeypot System for Detection

5. Implement Server Hardening with CIS Benchmarks

6. Use Just-In-Time (JIT) Access Controls

7. Implement Endpoint Detection and Response (EDR) Tools

8. Use Hardware Security Modules (HSMs) for Key Management

9. Apply Immutable Infrastructure Principles

10. Harden the Kernel with Grsecurity

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Maximum Security and Compliance-Driven Hardening (Level 6)

At the highest level, Linux server security must meet stringent regulatory compliance requirements while maintaining peak resilience against cyber threats. This guide covers advanced measures such as kernel hardening with Grsecurity, comprehensive security event management, and role-based access control (RBAC) enforcement for applications. Additionally, it emphasizes data retention policies and deception techniques such as honeytokens to detect unauthorized access. These measures ensure long-term security, forensic readiness, and strict compliance with industry standards.

1. Conduct Regular Compliance Audits

2. Create a Disaster Recovery Plan (DRP)

3. Enable Memory Protection with ExecShield

4. Set Up Security Information and Event Management (SIEM)

5. Restrict Access with Role-Based Access Control (RBAC) for Applications

6. Create a Data Retention Policy

7. Set Up Honeytokens to Detect Unauthorized Access