Knowledge Base

What is Linux?

Linux is an open-source, kernel-based operating system. Although it is only an operating system kernel, it is often used as a complete operating system along with GNU tools, desktop environments (GNOME, KDE, XFCE, etc.), and other applications. The term "Linux" often refers to the combination of the kernel and these tools.

• Open Source: The source code can be viewed, modified, and distributed by anyone.
• Kernel: Forms the basis of the operating system and provides communication between hardware and software.
• Distributions: Customized and packaged Linux systems for different purposes (Ubuntu, Fedora, Debian, CentOS, etc.).

What is the History of Linux?

The origins of Linux date back to 1991. A Finnish student named Linus Torvalds began developing his own operating system kernel inspired by an operating system called MINIX. This kernel, over time, developed with the contributions of the GNU project and other open-source communities to form the Linux of today.

1. 1991: Linus Torvalds released the first Linux kernel.
2. 1992: Linux was licensed under the GNU General Public License (GPL).
3. 1990s: Linux began to gain popularity in servers and embedded systems.
4. 2000s: Desktop Linux distributions became widespread (Ubuntu, Fedora).
5. Today: Linux is used in many areas, from servers to mobile devices, supercomputers to IoT devices.

Why is Linux So Popular?

There are many reasons for Linux's popularity:

• Being Open Source: Being free and customizable.
• Security: Security vulnerabilities can be quickly identified and fixed thanks to open source code.
• Stability: It is a stable operating system suitable for long-term operation.
• Flexibility: Distributions are available for different hardware and purposes.
• Community Support: Supported by a large and active community.
• Performance: In most cases, it performs better than Windows or macOS.

Real-Life Example: Google uses Linux on a large portion of its servers. The Android operating system is also based on the Linux kernel.

What is a Linux Distribution? How Many Types of Linux Distributions Are There?

A Linux distribution is an operating system package that is made ready for use by bringing together the Linux kernel, GNU tools, desktop environment, and other applications. Each distribution is customized for different purposes and users.

Common Linux Distributions:

Step-by-Step Instructions: To install Ubuntu, first download the ISO file from the official Ubuntu website (ubuntu.com). Then, write this ISO file to a USB drive (using tools like Rufus or Etcher). Start your computer from the USB drive and follow the installation steps.

What are the Advantages and Disadvantages of Linux?

Advantages:

• Free and Open Source: Cost advantage and customization possibilities.
• Security: Lower risk of viruses and malware.
• Stability: Long-term operation and fewer crashes.
• Flexibility: Distributions suitable for different hardware and purposes.
• Performance: Better performance in most cases.
• Community Support: Large and active community.
• Update: Constantly updated system.

Disadvantages:

• Learning Curve: Can be challenging for new users initially.
• Game Compatibility: Some games may not work on Linux or may experience performance issues.
• Driver Support: Finding drivers for some hardware can be difficult.
• Software Compatibility: Not all Windows or macOS applications may work on Linux (compatibility layers like Wine can be used).

What are the Basic Commands in Linux?

The Linux command line is a powerful tool used to control and manage the operating system. Here are some basic commands:

• ls: Lists files and directories.
• cd: Changes directory.
• pwd: Shows the current directory.
• mkdir: Creates a new directory.
• rmdir: Deletes an empty directory.
• rm: Deletes files.
• cp: Copies files.
• mv: Moves or renames files.
• cat: Displays file content.
• less: Displays file content in pages.
• grep: Searches for text in files.
• sudo: Executes a command with administrator privileges.
• apt-get (Debian/Ubuntu): Manages software packages.
• yum (CentOS/RHEL): Manages software packages.
• df: Shows disk usage.
• du: Shows directory size.
• ps: Lists running processes.
• kill: Terminates processes.
• top: Shows system resource usage in real-time.

Code Example:

# List all files and directories in the current directory
ls -l

# Go to the /home/user directory
cd /home/user

# Create a new directory
mkdir new_directory

# Copy a file
cp file.txt new_file.txt

# Delete a file
rm file.txt

Why is Linux So Common on Servers?

Linux is a leading server operating system. The main reasons for this are:

• Stability and Reliability: Linux servers are designed to meet the requirements of uninterrupted operation.
• Security: It is secure thanks to open source code and regular security updates.
• Performance: Optimized for high-traffic websites and applications.
• Flexibility: Adaptable for different server applications (web servers, database servers, email servers, etc.).
• Cost Efficiency: Being free reduces server costs.
• Customizability: Can be customized according to needs.

Case Study: Amazon Web Services (AWS) uses Linux in a large portion of its cloud computing services. This demonstrates the power and reliability of Linux in server environments.

How Can I Start Learning Linux?

There are many resources available to start learning Linux:

1. Choose a Linux Distribution: For starters, choose a user-friendly distribution like Ubuntu or Linux Mint.
2. Use a Virtual Machine: Install Linux on your computer using virtual machine software such as VMware or VirtualBox.
3. Learn Basic Commands: Learn how to use the command line.
4. Online Courses and Resources: Take Linux courses on platforms like Coursera, Udemy, and edX.
5. Books and Documentation: Read books about Linux and review the official documentation.
6. Join Linux Communities: Get help from other users by joining forums and mailing lists.
7. Experiment and Practice: Try different commands, develop projects, and actively use Linux.

Important Note: Learning Linux takes time and patience. You can become an expert in Linux by practicing regularly and continuing to learn.

Which Desktop Environments Can Be Used in Linux?

Linux supports different desktop environments. Each desktop environment offers a different look, feel, and feature set. Here are some popular desktop environments:

• GNOME: A modern, user-friendly, and customizable desktop environment.
• KDE Plasma: A feature-rich, customizable, and powerful desktop environment.
• XFCE: A lightweight, fast, and resource-friendly desktop environment.
• LXDE: A very lightweight desktop environment ideal for low-end computers.
• Cinnamon: A desktop environment designed for those who love the traditional desktop experience.
• MATE: A traditional and lightweight desktop environment that is a continuation of GNOME 2.

Visual Explanation: Each desktop environment has a different window manager, file manager, and application set. This offers users different experiences.

How is Security Ensured in Linux?

Various methods and tools can be used to ensure security in Linux:

• Strong Passwords: Use complex and hard-to-guess passwords.
• Firewall: Control network traffic using firewall tools like iptables or ufw.
• Updates: Regularly update the operating system and applications.
• Antivirus Software: Use open-source antivirus software like ClamAV.
• Limit Root Access: Use root access only when necessary.
• Security Audits: Perform security audits regularly.
• Two-Factor Authentication: Use two-factor authentication for SSH and other services.
• Log Monitoring: Monitor system logs regularly.
• SELinux or AppArmor: Enforce security policies using mandatory access control (MAC) systems.

Code Example:

# Enable UFW firewall
sudo ufw enable

# Allow SSH access
sudo ufw allow ssh

# Open a specific port
sudo ufw allow 80/tcp

What is the Future of Linux?

The future of Linux looks bright. Thanks to its open-source nature, flexibility, and reliability, it will continue to be widely used in many areas. In particular, Linux's role will increasingly grow in areas such as cloud computing, artificial intelligence, the Internet of Things (IoT), and cybersecurity.

Important Note: Linux knowledge is an important skill in today's technology world. Investing in learning Linux can be a valuable step for your career.