What is Linux?
The Linux Operating System
I am writing this article to explain what Linux is in a layman terminology. The aim of this article is to give enough introduction about Linux OS. 
What is Linux?
Linux is an Operating System like Windows.
What is special about Linux or why Linux?
** Linux is open source, which means FREE.
** Linux is multi-user, which means a couple of hundreds to thousands of users can use Linux system at the same time.
** Windows has the limitation on concurrent users. For example, if you have ever done a remote desktop (via RDP) to a Desktop Windows system it will log out from the other session. Windows server can do concurrent but limited to few tens.
** Linux is reliable, you can run a Linux system 24X7 for a couple of several years without rebooting it :). I personally have seen systems running for 5 years without interruption.
** Linux is powerful. The features and services available on Linux platform are almost unlimited compared to Windows. You can run a mail server, file server, name server (DNS), web server, Video streaming server, chat server, database server, music library, what not? All these are for FREE!!
** Linux has few thousands of code contributors, who just do for passion.
** Who uses Linux? Linux has various flavours for various domains and applications. Do you know there is a separate Linux variant called Kali Linux packaged with hacking tools (just for ethical hacking)? A separate Linux variant for astronomy and for scientific research and many more. All these are for free, amazing isn’t it?
** Linux is more secure than windows. There are very very fewer chances of a virus or malware attack. Also hard to break into Linux for intruders. Linux has inbuilt firewalls.
** Linux is portable. You can compile Linux with as many as modules as you want. Do you know Android platform runs on Linux OS?
** A mini computer called Onion Omega which costs $5 runs on Linux. It hosts a web server, a file server and is designed for IoT (Internet of Things) projects. You can connect to cloud and control connected devices, like turn off a light from mobile. Turn on Microwave oven from your mobile app to make a cup of coffee 🙂
** You can run Linux from a thumb drive (pen drive) on your Windows PC without the need of installing it. See How to create a Live Linux bootable thumb drive.
** If you are a developer, note that Linux development libraries are packaged with rich set of tools for amny programming languages like:
- compilers (gcc,g++,javac etc.,)
- debuggers (gdb etc.,)
- profilers (grpof etc.,)
- code coverage tools (gcov)
- Memory leak detection and profiling (valgrind)
- System call analysis (strace)
** There are endless specialities about Linux 🙂
How to learn Linux?
I think you are now excited to learn Linux. It is not tough at all. There are few variants of Linux which are friendly Desktop flavours like Windows. Ubuntu, OpenSuse and Fedora are good ones to start with.
OK, the first thing you must learn is shell commands.
What is Linux shell?
Shell is the interface between users and kernel. It has set of commands to get your basic things done. It takes input from the user and passes them to the kernel for execution and renders the results.
You can perform operations like creating files, setting permissions, deleting files, text processing, searching files, getting system resources info etc.,
There are many variants of Linux shell. Popular ones are bash, tcsh, csh and zsh. I would recommend you to start with bash. It is easy and widely adopted.
Start with shell commands and basic utilities you are good to go.
See the below artcile to know basic tools and commands.
I hope you now got some idea about “What is Linux?”. I will update this post with more details soon.