LINUX: AN OPERATING SYSTEM AND THE USE OF ITS COMMANDS

WHAT IS LINUX?
Linux is a free, open-source operating system (OS) that acts as an intermediary between computer hardware and software applications, managing resources and executing instructions. Created by Linus Torvalds in 1991, it is modeled on UNIX but has since evolved independently. Linux is known for its stability, flexibility, and security, making it popular for servers, desktops, and embedded systems.

Moreso, Linux is a versatile and powerful operating system that has found a broad range of applications, from personal computing to powering the world’s most complex supercomputers. Its design follows a Unix-like architecture, focusing on stability, performance, security, and flexibility. Here’s a deeper dive into what makes Linux unique and why it’s so widely used.

The key features of Linux as an OS include:

1. Open-Source Nature and Community Collaboration

• Freedom and Flexibility: Linux is open-source software, meaning anyone can view, modify, and distribute its code. This openness has led to widespread collaboration, with thousands of developers worldwide contributing to its evolution.
• Community Support: The open-source community is a massive asset, providing support, resources, and continuous improvements. This collaborative model encourages rapid innovation and quick identification and patching of security issues.
• Forking and Variants: Because of its open nature, developers can create customized versions or "forks" of Linux, resulting in a variety of distributions. Each distribution (e.g., Ubuntu, CentOS, Arch Linux) serves different needs, whether for servers, desktops, or lightweight embedded systems.

2. Security and Reliability

• Permissions and User Management: Linux’s design inherently prioritizes security. Permissions and user roles are strictly managed, limiting what users (and software) can do, which reduces the risk of malware and security breaches.
• Regular Security Updates: The collaborative model of Linux means that security vulnerabilities are often identified and patched quickly, helping it maintain a reputation for reliability.
• Strong Community Auditing: Linux is widely audited by security experts and developers worldwide, enhancing its robustness against threats.

3. Efficient Resource Management

• Lightweight and Scalable: Linux can run efficiently on hardware ranging from low-power microcontrollers to high-performance mainframes and supercomputers. This scalability makes it a go-to choice for diverse environments.
• Customizable Kernel: Users and developers can customize the Linux kernel to fit the exact hardware specifications and performance needs of the machine it’s running on, optimizing resource use.
• Ideal for Servers: Linux’s efficient resource management and stability make it a top choice for web servers, with over 90% of all servers on the internet running on a Linux-based OS.

4. Command Line Interface (CLI) and Scripting

• Powerful CLI: Linux’s command-line interface provides power users and system administrators fine-grained control over the system. From managing processes to editing configuration files, the CLI is a powerful tool for experienced users.
• Scripting and Automation: Linux has excellent support for scripting languages (such as Bash, Python, and Perl) that allow users to automate repetitive tasks, perform batch processing, and streamline system management.

5. Distributions (Distros) and Use Cases

• General-Purpose Distros: Distributions like Ubuntu, Fedora, and Debian offer user-friendly environments for everyday desktop users, developers, and business applications.
• Server-Specific Distros: Distributions like CentOS, Red Hat Enterprise Linux (RHEL), and SUSE are tailored for enterprise-level servers and critical applications, with a focus on reliability, support, and security.
• Minimalist and Embedded Systems: Lightweight distributions like Alpine Linux and Tiny Core Linux are ideal for devices with limited resources, such as embedded systems or IoT devices.
• Customizable Distros: Arch Linux and Gentoo provide a highly customizable experience, allowing advanced users to build their Linux system from the ground up.

6. Linux in Cloud Computing and Virtualization

• Cloud Dominance: Linux is widely used in cloud environments due to its scalability, security, and lightweight nature. Cloud providers like AWS, Google Cloud, and Microsoft Azure offer various Linux distributions as default images for cloud instances.
• Containerization with Docker: Linux's modular nature has made it the preferred OS for containerization platforms like Docker and Kubernetes. Linux Containers (LXC) and namespaces allow isolated environments within a single OS instance, driving efficiency in cloud-native applications.
• Virtualization Support: Linux provides robust support for virtualization with tools like KVM (Kernel-based Virtual Machine) and Xen, enabling multiple virtual machines to run on a single physical machine.

7. Educational and Development-Friendly Environment

• Tool Richness: Linux is favored by developers for its compatibility with programming languages, development tools, and version control systems like Git.
• Learning Platform: Many people start with Linux when learning programming, networking, or cybersecurity because it provides hands-on experience with these fields. Linux-based systems are also commonly used for running simulation and penetration testing labs, making them ideal for educational purposes.

8. Popularity and Adoption in Industry

• Web Hosting and Data Centers: Linux is the dominant OS in the world of web hosting, powering websites, APIs, and other internet services. The Apache and Nginx web servers, which are typically run on Linux, are among the most popular web server software.
• Supercomputing and Research: Over 90% of the world’s supercomputers run on Linux because it can handle massive workloads and be customized for high-performance computing (HPC) requirements.
• Mobile and Embedded Devices: Android, which is based on the Linux kernel, is the world’s most popular mobile OS. Additionally, many embedded systems like routers, smart TVs, and IoT devices run on customized Linux versions.

Downloading process and Navigating through Linux Commands

• Search the Web for Ubuntu Multipass Download

• Select the OS for the PC in use.

• Select and run any of the virtual Box given.

• The environment after the download and installation.

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Navigating through the Commands

The first command in the Linux environment is 'Sudo su'

• Sudo su: (Super User) puts you into the root environment. The SU command is used to run a function as a different user. It is the easiest way to switch or change to the administrative account in the current logged in session.

Navigating through File System

• pwd: means the current working directory. That is, it shows the current directory you are in.

ls: means List. It helps to know the list of things or items in the directory. For instance, in the below annotation, vicky and vicky 2 are the items already in the directory.

mkdir: mean Make Directory. A Directory is like a cupboard to make a new directory file.

• ls-l: it shows all the permission been given so far in the machine.

• cd: mean Change Directory

• Exist- mean moving out from the environment.

• Clear- mean clearing up of the the page.

File and Directory Operations

• touch: to create a new empty file e.g touch(name prefer to be given to the file)

• cp: mean copy a file from the source to a destination. e.g cp vickyresume (source file) ambassadorfile1(destination file)

• mv: move a file to a destination i.e from a source to a destination

• cat: mean display the contents of a file.

• rm: mean remove file or delete a file

In the image 1 above, the file named_ "dammie1.txt"_ was included but in image 2, the file name_ "dammie1.txt"_ has been removed.

• Commnand Mode: mean the environment a text file will be work upon. i.e it is an environment to type into before it is being edit, copy and the likes. For typing to be made in this environment, you type "I" which means "Insert"

Viewing and Editing a File

• cat: mean view the content of a file.

• less: (typing file name with "less"). This will enable the viewing of the contents of a file at one screen at a time.

• vim:(vim with filename) to edit a file, vim is use.It will also open a file and edit it.

More to the use of Vim.

In this write, we will dive deep into the world of Vim, a powerful text editor that is widely used in the Linux environment for creating and editing text files. Vim, short for Vi Improved, is a highly customizable and efficient text editor that offers a wide range of features to enhance your text editing experience. Let's explore how you can work with Vim to create and edit text files in Linux.

1. Opening Vim:
To open Vim, simply type 'vim' followed by the name of the file you want to edit. For example, to edit a file named 'example.txt', you would type 'vim example.txt' in the terminal.

2. Navigating in Vim:
Once you have opened a file in Vim, you can navigate through the text using the arrow keys or the 'h', 'j', 'k', and 'l' keys for left, down, up, and right movements respectively.

3. Editing Text:
To start editing text in Vim, press the 'i' key to enter insert mode. You can now type or paste text into the file. To exit insert mode and return to normal mode, press the 'Esc' key.

4. Saving and Exiting Vim:
To save changes to the file and exit Vim, you can use the following commands:

• Press ':w' and then 'Enter' to save the changes without exiting Vim.
• Press ':wq' and then 'Enter' to save the changes and exit Vim.
• Press ':q!' and then 'Enter' to exit Vim without saving changes.

5.Advanced Editing Techniques:
Vim offers a wide range of advanced editing techniques such as search and replace, copying and pasting, and navigating multiple files. By mastering these techniques, you can significantly improve your productivity when working with text files in Linux.

** How to Delete Directories and Files in Linux.**

In the world of Linux, knowing how to efficiently delete directories and files is a crucial skill for any Cloud DevOps professional. 🌟

Step 1: Deleting Files
Deleting files in Linux is a straightforward process. You can use the 'rm' command followed by the file name to remove a specific file. For example, to delete a file named 'example.txt', you would use the command 'rm example.txt'. Remember, this action is irreversible, so use it with caution. 💥

Step 2: Deleting Empty Directories
To delete an empty directory, you can use the 'rmdir' command followed by the directory name. For instance, if you want to remove a directory named 'docs', you would type 'rmdir docs'. Keep in mind that 'rmdir' can only delete empty directories. 📁

Step 3: Deleting Non-Empty Directories
Deleting directories with content requires a different approach. You can use the 'rm' command with the '-r' flag to recursively remove all files and subdirectories within the target directory. For example, to delete a directory named 'project' and all its contents, you would use 'rm -r project'. Exercise caution when using this command, as it will delete everything within the specified directory. 🚨

By mastering the art of deleting directories and files in Linux, you can effectively manage your system and free up valuable storage space. Practice these commands in a safe environment to become proficient in handling file deletion tasks.

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System Information and Management

• uname-a : this command will display detailed information about the system in use.

• df-h:(human-readable format) this command will display disk space usage.

• free-h: (human-readable format) this command will display the memory usage.

• top: this command will display the processes and system resource usage. That is, it will show that the system is running or in usage.

Searching and Finding

• grep: (pattern or search item). Grep with the name of the file being searched for_(grep information newfile.txt_).This command is used to search for a file in the situation where there are numerous files.

How to Quit vim/vi Editor

1. Press _Escape _key on your keyboard.
2. Press Shift and :
3. Type :wq

In Summary

Linux’s power, flexibility, and open-source nature have allowed it to permeate nearly every sector, from everyday devices like smartphones to specialized systems like research supercomputers. Its community-driven development and emphasis on security, efficiency, and customizability make Linux an enduring and evolving choice in modern computing.