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Linux System

Administration

Introduction To Linux Operating System

LINUX Is An Operating System Or A Kernel Distributed Under An Open-source

License. Its Functionality List Is Quite Like UNIX. The Kernel Is A Program At

The Heart Of The Linux Operating System That Takes Care Of Fundamental

Stuff, Like Letting Hardware Communicate With Software.

Linux

• Linux is Kernel not OS
• (^) Linux is not a UNIX derivative. It was written from scratch.
• (^) A Linux distribution is the linux kernel and a collection of software that together, create an OS.

Linux OS or Linux Distribution = Linux kernel + GNU

Features :

• (^) Open Source Code
• (^) Very Secure
• (^) Simplified updates for all installed software
• (^) Light weight
• (^) Multi User or Multitasker
• (^) Multiple distribution, like RedHat, Debian, Fedora…

Difference between Linux and other operating system

Parameters LINUX WINDOWS Inception Year 1991 1985 Standard Open source operating system which is freely available Closed Source Operating system Web Server Share 70% Share 23% Share Filesystem ext2-4, FAT, NTFS, NFS, ISO 9660, JFS, KFS NTFS, FAT, ISO 9660, UDF, HFS Cost Low cost Hardware High cost Hardware Security Secure Insecure Virus 60 - 100 virus listed 60,000 virus listed Developed by Linus Torvalds Microsoft Source Code There is full access to source code There is no access to source code Configuration Storage Maintains configuration in files Maintains a registry to store configurations

Linux OS working The linux operating system follows of standard design that's the key to its several distributions and variations. Every linux distribution is based on the linux kernel but can differ based on factors like: kernel version: distros can be set up with more recent releases to add new aspects or with previous releases to be more balanced. Kernel modules: it is software that can be unloaded and loaded into the kernel develop functionality without restarting. Often, kernel modules are used for supporting:

• device drivers, which utilize code that manages how linked devices work.
• File system drivers, which utilize code that manages how the kernel operates with distinct file systems.
• System calls, which utilize code that manages how programs claim services through the kernel.

Terminal & Shells (Bash, Zsh)

A terminal (or terminal emulator) is a program used to interact with the operating system through text rather than a graphical interface. The shell is the program that interprets the commands you type in the terminal and executes them. ● (^) Bash (Bourne Again Shell) has been the default shell for many Linux distributions and macOS (until recently) for years. ● (^) Zsh (Z shell) is a more modern, extended version of Bash that offers numerous improvements, such as better tab completion, themes, and plugin support. It is the default shell for macOS since Catalina. Most basic commands function identically in both Bash and Zsh.

Linux Directory Structure

In Linux/Unix operating system everything is a file even directories are files, files are

files, and devices like mouse, keyboard, printer, etc. are also files. Here we are going to

see the Directory Structure in Linux.

Types of files in the Linux system

General Files – It is also called ordinary files. It may be an image, video,

program, or simple text file. These types of files can be in ASCII or Binary format. It is

the most commonly used file in the Linux system.

Directory Files – These types of files are a warehouse for other file types.

It may be a directory file within a directory (subdirectory).

Device Files – In a Windows-like operating system, devices like CD-

ROM, and hard drives are represented as drive letters like F: G: H whereas in the Linux

system devices are represented as files. As for example, /dev/sda1, /dev/sda2, and so on.

Virtual Lab Environment

Used Software and Operating Systems

- Virtualbox OR VMware for Virtualization

• Linux OS (Ubuntu, Kali or Others) Virtualization Virtualization is a technology that allows to create and manage virtual machines. Using virtualization, we can install multiple virtual machine and operating system in a single physical system.

Top 50 Linux Commands You Must Know as a Regular User

ls - The most frequently used command in Linux to list directories pwd - Print working directory command in Linux cd - Linux command to navigate through directories mkdir - Command used to create directories in Linux mv - Move or rename files in Linux cp - Similar usage as mv but for copying files in Linux rm - Delete files or directories touch - Create blank/empty files ln - Create symbolic links (shortcuts) to other files cat - Display file contents on the terminal