Hi everyone,

Today, we are diving into the fascinating world of Linux🐧. Whether you’re a beginner or someone who’s looking to sharpen your Linux skills, this blog introduces you to the fundamentals of the Linux terminal and its powerful commands.

This is Part I of the Linux blog series, where we will explore the basics of the Operating system, Linux and its flavours, architecture, and some commands for file management, networking, and file permissions. So, let’s dive in!

Why should you learn Linux?

As per Stack Overflow’s insights, the most common and most loved platform happens to be Linux. If you do a quick search online on Linux, you’ll come across some fascinating statistics.

All of the fastest 500 supercomputers in the world run on Linux.
96.3% of the top 1 million web servers run on Linux.
86% of all smartphones are powered by Linux.

Some great numbers! In the cloud and DevOps world, many modern tools are developed and used in Linux environments first before they are made available on Windows/Mac.

For example:

Automation tools like Ansible require a Linux environment for the Ansible controller (even though Ansible can manage Windows systems as targets).
Containerization tools like Docker were initially exclusive to Linux-based systems. Even now on Windows, if you’re containerizing an app, under the hood, it runs a Linux instance on top of a Windows machine.

So, you have pretty good reasons😄 to learn Linux and make something out of it.

What is Operating system?

Before diving into Linux, let’s brush up on some basics!

An operating system is a system software that acts as an intermediary between the user and the computer hardware. It allows you to run programs, use your keyboard and mouse, save files, connect to the internet, and get stuff done.

The flow of communication goes like this: As a user, you’re interacting with a software app(any) on your machine, which then forwards the request to the OS, followed by the kernel that’s present on top of the hardware. Here’s what a typical OS looks like,

System software means the software(Java code) that runs on the system, and with every request you make, it runs a process with a compiler(JDK-runtime) and then the system libraries(java package) forward to the kernel, that’s on top of your hardware, which comprises CPU, RAM and I/O. And, that’s how the Operating System works by.

Some key functions

Process management
Memory management
System calls
Device management

Linux Specific Features

Fast and stable
Widely used in production systems
Free and open source
Multiple distributions available
Very secure (no need for anti-malware like McAfee on Windows)

Installation and set-up

In this blog, we will be doing it by installing WSL(Windows subsystem for Linux) that allows you to run Linux on your Windows machine, which uses a lightweight virtual machine to run a full Linux kernel.

WSL works by the Virtualization principle via Hyper-V(More on this later). If you’re using,

Mac OS - This OS itself is a Unix-based one. So, most of the commands can work on zsh, bash shells. Therefore, you don’t have to install Linux separately.
Linux - Setup is already done, as the core itself is the Linux OS.
For Windows, you can use WSL as we saw before. Here’s how you can do it👇!

That’s it, we are done with the Installation part✅. Make sure that you’ve the necessary memory space available before doing it. If not, then don’t worry, I’ve got a better solution for that as well😄.

Navigate to https://killercoda.com/playgrounds/scenario/ubuntu and sign up. Toggle on the start playground, and it opens Linux Ubuntu 24.0 kernel right inside your browser. How cool is that🐱? Every command works as it is, but remember it lasts for just an hour. And then, you can start with another playaround.

Linux distributions

Similar to Icecream🍨, Linux also has many flavors in it,so called distributions. Each serves for different purposes and has its own usecases. Major distributions are,

Arch Linux	Lightweight,rolling base distro providing full customization.
Debian	Stable one acting as foundation for many distros including ubuntu.
Fedora	Cutting edge by redhat used for development purposes.
Ubuntu	user friendly debian based distro for desktops and servers.
CentOS	RHEL Compatible distro
Open SUSE	A versatile one by SUSE for sys admins and devs.

Ubuntu - Architecture

Everything you install in your machine is sort of a executable — A folder simply!(Running it actually means like double-clicking on that folder). When you install Linux, it comes up with below folders featuring a home page,user files,system boot(reboot,off),a temp folder,etc folder consisting config files and then a bin folder like every operating system.
You can view the same in File Explorer on your Windows (Literally the same)!

Terminal and shell

Shell: A shell is a command-line interpreter that serves as the interface between the user and the operating system. It takes commands from the user, interprets them, and then executes the corresponding programs or system calls. Eg: Bash,zsh

Terminal-Emulator: It’s a software application that mimics the functionalities of old physical terminals(like VT100) on modern graphical user interfaces.It provides a window where users can interact with the shell. Eg: Powershell,command prompt.

Environmental variables

Think of them like digital sticky notes your system uses. Environment Variables are set at the system level and affect the environment of processes and users.

These’re just key-value pairs used by your OS and app to store important configuration info. It’s tells us about where to find the files,which editor to use,what the system language is,and some user-specific settings($PATH,$HOME,$SHELL).

env	Lists all current env variables.
printenv	Prints a specific or all env variables.
export	sets or modifies env vars.
source	runs a script in the current shell.
where git	shows the path of the installed git.
open /usr/bin	open the bin folder
echo $PATH	Displays the path vars.
ps,kill	used to view running processes and terminate them by process ID.

File management

Linux gives you powerful commands to create, view, move, search, compress, and clean files and folders.

Navigate & Explore

ls	list files and directories
pwd	prints your current directory
cd	changes your directory
mkdir	creates new folder
cat	display file content
less,more	view long pages by page
echo	print statement or file content
cat	read the file content

Organize files

cp	copies files/folders
mv	moves or renames files/folders
rmdir	removes empty directory
clear	clears your terminal screen

Find & search, compression

find	Locates files by name,type etc
grep	searches inside file contents
zip/unzip	Compress and extract files

Networking in Linux

Networking is how your computer talks to other systems(locally or over the internet).Linux provides handy tools to check connectivity,transfer files,debug and manage network interfaces.

Test your connectivity

ping google.com	checks if a website or IP address is reachable or not.
ipconfig (or ifconfig in Linux)	Displays your network interface details(IP,subnet, etc..,)

Transfer files & Interact

curl	Fetches content from a URL/API(GET,POST,etc..,)
wget	Downloads files from the internet.
ftp	Transfers files using the FTP protocol.

Remote login & Access

ssh	securely connects to a remote server over the network.
telnet	connects to remote machines(older and insecure)

Troubleshooting

netstat/traceroute	show open ports,network connections & routing tables.

File permissions

File permissions in Linux OS allows us to control who can do what with a file or directory as it is a multi user system.

Combined values:

7 = 4 + 2 + 1	read-write-execute(rwx)	View the content of file
6 = 4 + 2	read-write— (rw-)	Modify or delete the file
5 = 4 + 1	read- — -execute(r-x)	Run the file as a program/script.
0	- - -	No access at all.

Commands

ls -ltr	shows a long listing of files, sorted by time, with permissions visible.
chmod	change mode(read/write/execute)
chown	change owner(user or group)

Conclusion

And that’s it, we reached the end of the blog, and I have walked you through a lot, literally! As a beginner, it might seem overwhelming with its endless commands and configurations, but once you take the plunge, you’ll discover a world of power, flexibility, and control.
I highly recommend you to try experimenting with these commands in the terminal and play around with them for a while to get you grounded.
With time, it becomes natural and easy for you!

Thank you💙 so much for your time! I will see you soon with my next blog😄
Until then, Byeeee👋

Bye Dog GIFs | Tenor

💡Let’s connect! Feel free to reach out:
LinkedIn
GitHub

Introduction to Linux - Part I

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