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Understanding Linux Concepts

What is Linux?



Linux is an operating system that resides in the middle of the hardware and the end-users who actually run the applications. It is just like any other operating systems like Microsoft has Windows, Mac has Apple or Sun has Solaris.

It acts like a middle man or bridge which receives instructions from the end-users and then interprets them to the hardware. Let us consider a computer, without the operating system installed in it is more like a dumb terminal.

We have to install the operating system to the computer with the help of a CD or DVD which contains the operating system image on it. We have to boot a computer. While booting it goes through the several installation processes

While going through the installation process, we have to answer a bunch of questions like the configuration of the operating system, the number of users to be installed, and so on. Once done we have to reboot our system.

Next, we shall be on the operating system welcome screen. We can now connect external devices like monitors, mouse, and so on. We can type a certain command with the mouse and send it to the operating system.

The operating system accepts those instructions and reverts the required hardware or other system peripherals. For example, we can enter some text in a Microsoft word document and print it via a printer or running other programs like checking emails online, playing games.

Some of the actions performed by operating systems on the applications are listed below:

  • The operating system allows multiple tasks to be run simultaneously. It determines the sequence and duration for a program to run before giving chance for another application to run.
  • The operating system manages the resource sharing among different programs.
  • The operating system monitors the interactions from and to the connected devices like printers, disks, and so on.
  • The operating system informs each application about the status of the task that it is intended to perform and any errors that have come up.
  • The operating systems which have parallel processing features can decide how to segregate the program so that it can execute on multiple processors simultaneously.
Some of the popular operating systems are Redhat, Microsoft Windows, Apple macOS, Ubuntu Linux, Google Android, and iOS.

Unix vs Linux

  • Unix was first developed to support multiple tasking and multiple users during the mid-1970 in Bell Labs by AT&T GE and Massachusetts Institute of Technology.
  • Linux was developed in the year 1991 by Linus Torvalds.
  • Linux is free which means it can be installed on any computer hardware.
Please note some of the Linux distributions are not free like the Redhat where we have to pay for support.
  • Linux is open-source. This means that the Linux code which is derived from Unix is open to the public so that they can make changes to the code as per their requirement.
  • Unix is mostly used by Sun and its operating system is called the Solaris. Other Unix-based operating systems are HP-UX, AIX, and so on.
  • Linux is commonly used by developer communities and companies like Redhat, CentOS, and so on.
  • Unix supports very fewer file systems than Linux.
  • Linux can be installed on a large range of computer hardware like tablets, video games, mainframes, supercomputers, and so on.
  • Just like Mac operating systems can be installed only in Mac hardware, Unix can be installed only on specific hardware whereas Linux can be installed on a large range of hardware.

Inside Linux

Linux comprises of the below components:

Kernel

The kernel is considered the heart of the Unix system and loaded at booting time. It is primarily responsible for controlling and allocating a machine's memory to individual processes. It takes care of scheduling the jobs carried out by the CPU.

The kernel handles data transfer from one part of the machine to another. It translates and executes the instructions from the shell and applies for permissions on file access.

Shell



Once we login into the Unix system we are within the shell program. In order to execute the commands, we have to be in the shell prompt displayed at the position of the cursor on the screen.

The shell acts as a command translator. It accepts the user commands and transfers it to the kernel to be worked upon. The results of the command execution are then displayed on the screen.

Some of the popular shells available are C shell, Korn shell, Bourne shell, TC shell, and Bourne Again Shell.
Utilities

Unix has numerous utility programs, popularly called commands. The utilities perform several operations like sorting, printing, programming assistance, file maintenance, editing, obtaining online information, and so on.

Also, individual functions can be clubbed together to do complicated actions.

The popular Linux Distributions are listed below:

  • Redhat - It is not open-source. Redhat gives technical support and provides patches/ fixes.
  • CentOS - It is exactly the same as Redhat and also managed by it. CentOS has no technical support. It is free.
  • Fedora - It is sponsored by Redhat and is free.
  • Suse
  • Debian
  • Ubuntu.
Feature Windows Linux
Cost It comes with a cost. It does not come with a cost.
Ease User-friendly Not user-friendly
Reliability Not reliable. Requires rebooting Extremely reliable
Software Have a wide range of software. Mostly enterprise-related software
Multitasking Requires additional resources for multi-tasking. Good at multi-tasking.
Security Not so secure Good in security

Linux Users

The Linux users include:

  • NASA
  • Financial Institutions like NYSE.
  • Entertainment industries.
  • Traffic Control.
  • Bullet Trains.
  • Popular e-commerce companies like Amazon, Walmart.
  • Fortune 500 companies like IBM, Google.
  • Health Care
  • Various government services.

Keyboard Keys Used in Linux

The keyboard keys used in Linux are pointed in blue in the below image.

Running Linux in Web Browser

If we do not have enough resources on our computer, or we want to test or execute certain commands on a Linux machine as a practice without using our own Linux machine, we can do that by opening a browser and use certain websites that allow starting Linux instance on their servers.

We shall be able to access them through our browsers.

About Author :

Myself Debomita Bhattacharjee, an IT employee with 6+ years of experience in Software industry. My area of interest is Automation testing and Front End Development.

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