Introduction to Linux and Shell Scripting

What is Linux

Linux is a free and open-source operating system; more specifically, it is the kernel.

To understand it better, let's discuss what an operating system (OS) is. An OS is the software installed on a machine to manage resources like RAM, memory, CPU, and more. It acts as a mediator between applications and hardware.

An OS consists of the kernel and some software, with the kernel being the heart of the operating system.
The main tasks of the kernel are:

1. Device Management

2. Memory Management

3. Process Management

4. Handling System Calls

Why Linux

Most applications are built and tested on Linux servers. The reasons for this are that it is free, open-source, fast, secure, lightweight, and has multiple distributions available. It was developed by Linus Torvalds.

What is SHELL

A shell is a command-line (CLI) interface that allows users to communicate with the kernel. There are different types of shells like sh, bash, zsh, ksh, etc.

Shell scripting is important for automating the daily tasks of a DevOps engineer, which is why it is essential.

Some Basic Shell Commands

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1. pwd : print the present working directory
2. ls : lists the files and folder in present working directory
3. cd : change the current directory
4. cp : copy files
5. mv : move and rename files
6. touch : for creating empty files
7. rm : remove files and directory
8. echo : print in terminal

Working with files in Linux

1. cat

   cat command in linux is used to view the content of file, but it can also be used to override and concatenate the file content.

2. touch

   touch command is used to create empty files.

3. vi

   vi is a text editor used to create, view content and writing into files in linux,

   while opening the files in vi, it opens in command mode, to write into file press

   any of the character A,I,O,a,i,o and the one can write into file.
   to save the file press esc and the :wq! , hit enter.

4. nano

   nano is also a text editor like vi.

That'a all about introduction to linux and Shell Scripting.