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Introduction - Day -1

We will start this training on RHEL7.3
Normally there are 3 ways to interact with any OS-
1. GUI(graphical user interface) - In simple words we can say interacting with OS using mouse. This the same way you are interacting with Windows.
2. CLI(Command line interface) - In this way user can't use mouse because there we don't have any graphics(icons/buttons) so that you can double click and open the things and select etc.
3. API(Application programming interface) - Normal user don't this, it is specially for developers

Here I'll talk about CLI, whatever things you do in GUI, 99% of them you can do from CLI as well. The beauty of CLI is that we can do the things very fastly and also it requires very limited/less resource(compute unit or we can say RAM/CPU etc..).

Let's take an example how CLI is faster than GUI-
Use case: Open 100 terminals - This task can be completed in two way
(A) - GUI(Right Click on home screen and then select open terminal, same thing we have to do 100 times and at the end of this task 100 terminals will be opened). Which is initially OK but I don't like this kind of manual effort. We can do the same thing very smartly and easily with computer speed. May be manually it take 10 minutes but using CLI it can be done within few steps. To understand this in detail, please watch this video....
(B) - CLI

One more use case I want to tell you, whenever we give any input using mouse(double click to open something) in background some program executes by some command and we know very well that executable state of any program is known as process and this process will complete the task which we have give to system.
Let me explain in more simple words, for example lets suppose you have a requirement so that you want to launch #Firefox in your system, so that you will double click on Firefox icon and after few milliseconds Firefox is ready in front of you. But think in another way, what exactly happen in background when you clicked on Firefox icon, if somehow you know that then you can fix below kind issue in case you come across in future
Mouse is not working - then you can run the program manually and launch firefox easily. It is just starting so I am not going into very much technical but this is not a small thing, if you know that program name then you can do lots of things. we will discuss in future.
To explain these things in more easy way I am preparing a video please watch and clear you concept and enjoy the things....For video Click here...
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