Introduction to Linux
Linux is an operating system similar to windows. An operating system is software that manages all of the hardware resources associated with your desktop or laptop. In another words, the operating system manages the communication between installed software and your hardware. Without the operating system the software wouldn’t function.
Distributions (Distros) in Linux operating systems are as follows:
- Ubuntu Linux.
- Linux Mint.
- Arch Linux.
Desktop screen of Ubuntu Linux distros
The OS contains following pieces:
- The kernel: This is the one piece of the whole that is actually called “Linux”. The kernel is the core of the system and manages the CPU, memory, and peripheral devices. The kernel is the “lowest” level of the OS.
- The Bootloader: The software that manages the boot process of your computer. For most users, this will simply be a splash screen that pops up and eventually goes away to boot into the operating system.
- Daemons: These are background services (printing, sound, scheduling, etc) that either start up during boot, or after you log into the desktop.
- The Shell: The shell acts as an interface between the user and the kernel. When a user logs in, the login program checks the username and password, and then starts another program called the shell. The shell is a command line interpreter (CLI). It interprets the commands the user types in and arranges for them to be carried out. The commands are themselves programs: when they terminate, the shell gives the user another prompt (% on our systems).The adept user can customise his/her own shell, and users can use different shells on the same machine. Staff and students in the school have the tcsh shell by default.The tcsh shell has certain features to help the user inputting commands.Filename Completion – By typing part of the name of a command, filename or directory and pressing the [Tab] key, the tcsh shell will complete the rest of the name automatically. If the shell finds more than one name beginning with those letters you have typed, it will beep, prompting you to type a few more letters before pressing the tab key again.History – The shell keeps a list of the commands you have typed in. If you need to repeat a command, use the cursor keys to scroll up and down the list or type history for a list of previous commands
- Graphical Server: This is the sub-system that displays the graphics on your monitor. It is commonly referred to as the X server or just “X”.
- Desktop Environment: This is the piece of the puzzle that the users actually interact with. There are many desktop environments to choose from (Unity, GNOME, Cinnamon, Enlightenment, KDE, XFCE, etc). Each desktop environment includes built-in applications (such as file managers, configuration tools, web browsers, games, etc).
- Applications: Desktop environments do not offer the full array of apps. Just like Windows and Mac, Linux offers thousands upon thousands of high-quality software titles that can be easily found and installed. Most modern Linux distributions (more on this in a moment) include App Store-like tools that centralize and simplify application installation. For example: Ubuntu Linux has the Ubuntu Software Center which allows you to quickly search among the thousands of apps and install them from one centralized location.
Ubuntu software center can be seen as a briefcase icon in task bare of Ubuntu desktop
Under this briefcase icon all available application in OS can be seen
Why use Linux?
Operating system will not be affected by virus, malware and slow downs.
It provides a lot of applications, which can be installed from Ubuntu software center
Open source i.e these OS can be download free of cost from official websites.
Open source follows the following key philosophies:
- The freedom to run the program, for any purpose.
- The freedom to study how the program works, and change it to make it do what you wish.
- The freedom to redistribute copies so you can help your neighbour.
- The freedom to distribute copies of your modified versions to others.
Files and processes
Everything in Linux is either a file or a process.
A process is an executing program identified by a unique PID (process identifier).
A file is a collection of data. They are created by users using text editors (such as vi, vim and gedit ), running compilers etc.
Examples of files:
- a document (report, essay etc.)
- the text of a program written in some high-level programming language
- instructions comprehensible directly to the machine and incomprehensible to a casual user, for example, a collection of binary digits (an executable or binary file);
- a directory, containing information about its contents, which may be a mixture of other directories (subdirectories) and ordinary files
Due to above mentioned features, Linux is getting popularity day by day. Now a days it has become first choice of scientists, researchers and industrialists.
Also those of you who have problems regarding installation of linux ubuntu can follow this article
Ubuntu : Step by step guide on how to install using DVD or USB