Reset Root User Password in CentOS Linux

Steps

Step1 – In the boot grub menu select option to edit.

 Step2-Select Option to edit (e).

Step3-Go to the line of Linux16 and change ro with rw init=/sysroot/bin/sh.

Step4-Now press Control+x to start on single user mode.

Step5-Now access the system with this command. Type

#chroot /sysroot

Step6-Reset the password by typing command

#passwd root

Step7-Update selinux information

#touch /.autorelabel

Step8-Exit from chroot type

#exit

Step9-Reboot the system

#reboot

Done.

Linux CentOS Step by Step Installation

Step 1- Boot from bootable DVD or Pendrive & select Install CentOS 7

On our next step just press ENTER to begin the installation process.

Step 2-Choose Installation Language.

Step3- Installation Summery

You should now see a screen with title Installation Summary. Actually this window has all the options that user can configure.

There are three main categories −

• Localization
• Software selection
• System this will see one by one:

•  

  Localization-This setting option Data & Time, Keyboard & Language support setting.

• Software Selecion-This category has options that deal with software being installed.
   If Select Minimal Install-Linux install in CLI Mode.
  GNOME or Other GUI mode installation.
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Components of Linux System

inux Operating System has primarily three components

• Kernel − Kernel is the core part of Linux. It is responsible for all major activities of this operating system. It consists of various modules and it interacts directly with the underlying hardware. Kernel provides the required abstraction to hide low level hardware details to system or application programs.
• System Library − System libraries are special functions or programs using which application programs or system utilities accesses Kernel's features. These libraries implement most of the functionalities of the operating system and do not requires kernel module's code access rights.
• System Utility − System Utility programs are responsible to do specialized, individual level tasks.
  
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Basics Of Linux OS

Linux is one of popular operating system based on Unix. 

It is open source as its source code is freely available.

It was developed by Linus Torvald in 1991 when he was an student at Hensilky University.

Available on CUI & GUI mode.

Different Flavours of Linux

Linux comes in many different guises. The basic system is the same, but the look and feel and the subsystems around it are different. Each version is produced by a different organisation with it's own ethos and aims. 

• Redhat 
• Ubunntu
• Fedora
• Linux Mint
• Suse
• Debian
• Caldera
• Mandriva
• CentOS
• Gentoo