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📖 Table of Contents

🔥 Basic Features of Linux

⚖️ Unix vs Linux Comparison

🏆 Popular Linux Distributions

🏗️ Layered Architecture of Linux

🔧 How to Get a Linux System

📜 Early Roots (1960s–1980s) Unix (1969–1970s): Developed at AT&T Bell Labs, Unix became a multi-user, multitasking OS. Why Linux? Unix was not free, leading to the need for an open-source alternative.	🚀 Growth & Open Source (1990s) GNU Project: Richard Stallman’s FSF initiated GNU to replace proprietary Unix. Linux + GNU: The Linux kernel combined with GNU tools created a complete OS.
🐧 The Birth of Linux (1991) Created by: Linus Torvalds as a hobby project. First Release: August 25, 1991.

🚀 Growth & Open Source (1990s)

• GNU Project: Richard Stallman’s FSF initiated GNU to replace proprietary Unix.
• Linux + GNU: The Linux kernel combined with GNU tools created a complete OS.

🌍 Widespread Adoption (2000s–Present)

• Linux Distros: Red Hat, Debian, and Ubuntu made Linux widely accessible.
• Servers & Data Centers: Linux dominates due to reliability, performance & cost-efficiency.
• Android: Based on the Linux kernel, it became the world’s leading mobile OS.
• Git: Created by Linus Torvalds, revolutionizing version control.
• Cloud & IoT: Powers cloud computing, containerization (Docker, Kubernetes), and embedded systems.

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🔥 Basic Features of Linux

• 🖥️ Portable: Runs on different hardware platforms.
• 🔓 Open Source: Freely available source code.
• 👥 Multi-User: Supports multiple users simultaneously.
• 🛠️ Shell: Command-line interface to interact with the system.
• 🔐 Security: Highly secure and stable.

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⚖️ Unix vs. Linux Comparison

Feature	Unix	Linux
Cost	Proprietary (Paid)	Free & Open Source
Source Code	Closed	Open Source
Users	Mainly Enterprises	Individuals & Enterprises
Security	Secure	Highly Secure
Customizability	Limited	Highly Customizable
Distributions	Single (varies by vendor)	Ubuntu, Fedora, Debian, etc.

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🏆 Popular Linux Distributions

1. Red Hat Enterprise Linux (RHEL)
2. Fedora Linux
3. Debian Linux
4. SUSE Enterprise Linux
5. Ubuntu Linux

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🏗️ Layered Architecture of Linux

• Hardware Layer: Physical devices like CPU, RAM, HDD.
• Kernel Layer: Core component managing hardware resources.
• Shell Layer: Command-line interface between users and the kernel.
• User Layer: Applications and utilities that interact with the shell.

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🔧 How to Get a Linux System

1. Install directly on a Laptop or Desktop.
2. Use a Virtual Machine (VMWare/VirtualBox).
3. Provision a Linux VM on cloud platforms (AWS, Azure, GCP).
4. Use a Docker Image for lightweight experimentation.
5. Try an Online Linux Terminal for practice.

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🚀 Linux is Everywhere! Embrace Open Source! 🐧

📚 Linux Commands Cheat Sheet 🐧

📑 Table of Contents

1. Basic Linux Commands
2. File and Directory Operations
3. View Files (Open/Read)
4. File and Directory Management
5. Advanced Usage
6. Visuals & Examples
7. Usage Tips
8. Resources
9. Contributing

A comprehensive cheat sheet of essential Linux commands to help you navigate, manage files, and perform administrative tasks easily!

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🔑 Basic Linux Commands:

📖 Manual Pages:

• man <command>: Show the manual of a specific command. (man cal)

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💻 File and Directory Operations:

📂 Directory Navigation:

• pwd: Print the current working directory.
• cd <directoryname>: Change directory.

🧹 Clear Screen:

• clear: Clear the terminal screen.

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🗂 View Files (Open/Read):

📜 Display File Contents:

• ls: List files in the current directory.
• cat <filename>: Display file content.
• less <filename>: View file content page by page. (Use space to scroll, q to quit)
• more <filename>: Similar to less but displays content in percentage. (Use space to scroll, q to quit)

🔝 Top/Last Lines:

• head -<num_of_lines> <filename>: Show the first n lines of a file.
• tail -<num_of_lines> <filename>: Show the last n lines of a file.

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🛠 File and Directory Management:

📝 Create/Edit Files:

• touch <filename>: Create a new empty file.
• cat > <filename>: Create a file and start writing content.
• nano <filename>: Create/edit a file with the nano editor.
• vi <filename>: Create/edit a file with the vi editor.

❌ Remove Files:

• rm <filename>: Remove a file.
• rm -rf <directoryname>: Remove a directory and its contents.

🏗 Create and Remove Directories:

• mkdir <directoryname>: Create a new directory.
• rmdir <directoryname>: Remove an empty directory.

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⚙️ Advanced Usage:

• sudo: Execute a command as another user (commonly root).
• chmod: Change the permissions of files or directories.
• chown: Change file owner and group.

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🎨 Visuals & Examples:

💡 Here's an example of using the ls command to list files in a directory:

$ ls
file1.txt  file2.txt  my_directory/

$ cat file1.txt
This is the content of file1.