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CSS Selector Cheat Sheet with Advanced Bitwise Operators

Basic Selectors

Selector	Example	Description
*	* { }	Selects all elements
elementname	p { }	Selects all <p> elements
.classname	.intro { }	Selects all elements with class="intro"
#idname	#firstname { }	Selects the element with id="firstname"

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Rust-Based Web Crawler with Kafka and PostgreSQL Integration - Design Specification

1. Introduction

1.1 Overview

This document outlines the design specification for a high-performance Rust-based web crawler integrated with Apache Kafka and PostgreSQL. The crawler will act as a worker within a distributed system, consuming URLs from Kafka topics, crawling the associated web pages, and storing the results in a PostgreSQL database. Docker Compose will be utilized to manage the infrastructure, ensuring seamless deployment and orchestration of the services.

1.2 Objectives

• Develop a high-performance web crawler using Rust that integrates with Kafka and PostgreSQL.
• Ensure scalable crawling of up to 10 million websites.

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🔐 The Ultimate Guide to Managing Multiple SSH Keys

🚀 Basic Concepts

• 🔑 SSH keys consist of a public key and a private key
• 📂 Keys are typically stored in ~/.ssh/
• 🔒 Private keys should be kept secure and never shared
• 📤 Public keys are added to remote servers or services

📊 Creating SSH Keys

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🔍 The Ultimate Grep Command Guide

🚀 Basic Usage

Command	Description	Example
grep pattern file	🔎 Search for a pattern in a file	grep error logfile.txt
grep -i pattern file	🔠 Case-insensitive search	grep -i ERROR logfile.txt
grep -w word file	🔤 Match whole words only	grep -w error logfile.txt
grep -v pattern file	❌ Invert match (show lines that don't match)	grep -v success logfile.txt

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📜 The Ultimate Tail Command Guide

🚀 Basic Usage

Command	Description	Example
tail file.txt	📄 Display the last 10 lines of a file	tail /var/log/syslog
tail -n 20 file.txt	🔢 Display the last 20 lines of a file	tail -n 20 /var/log/auth.log
tail -c 100 file.txt	📏 Display the last 100 bytes of a file	tail -c 100 /etc/passwd

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🐧 Linux Penetration Testing with GNU Utils: The Ultimate Cheat Sheet

DISCLAIMER: This information is for educational purposes only. Always obtain proper authorization before performing any penetration testing activities. Unauthorized testing is illegal and unethical.

🔍 Information Gathering

Command	Description	Example
netstat	🌐 Network connections, routing tables, interface statistics	netstat -tuln
ss	🔌 Socket statistics	ss -tuln

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📊 Log Analysis Mastery: The Ultimate Cheat Sheet

📜 Basic Log Viewing

Command	Description	Example
cat	📄 Display entire log file	cat /var/log/syslog
less	📃 View log file with pagination	less /var/log/auth.log
tail	🔚 View end of log file	tail /var/log/apache2/access.log
head	🔝 View beginning of log file	head /var/log/mysql/error.log

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🚀 GNU Parallel Mastery: The Ultimate Cheat Sheet

📊 Basic Usage

Command	Description	Example
parallel echo ::: A B C	🔤 Process items in parallel	Output: A, B, C (in any order)
parallel echo {} ::: *.txt	🔍 Use {} as placeholder	Echoes names of all .txt files
cat file.txt | parallel echo	📥 Read input from stdin	Processes each line of file.txt
parallel -j4 command ::: item1 item2 item3	🔢 Limit to 4 jobs at a time	Runs 'command' on items, max 4 parallel

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🔗 Bash Command Chaining Mastery: The Ultimate Cheat Sheet

🔗 Basic Command Chaining

Operator	Description	Example
;	📊 Run commands sequentially	echo "Hello"; echo "World"
&&	✅ Run next command only if previous succeeds	mkdir dir && cd dir
||	❌ Run next command only if previous fails	ping -c1 google.com || echo "Offline"
|	🚿 Pipe output of one command to another	ls -l | grep ".txt"

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🔐 SSH Mastery: The Ultimate Guide

🌟 Basic SSH Commands

Command	Description
ssh user@hostname	🔌 Connect to a remote host
ssh -p 2222 user@hostname	🔢 Connect using a specific port
ssh -i ~/.ssh/id_rsa user@hostname	🔑 Connect using a specific identity file
exit or logout	👋 Terminate the SSH session