Define CentOS

CentOS stand for Community Enterprise Operating System. It is one of the Linux Distributions started by Gregory Kurtzer. It provides an enterprise-class free and open-source Operating System, which is also functionally compatible with the Red Hat Enterprise Linux (RHEL).

The CentOS Linux distribution is a stable, predictable, manageable and reproducible platform derived from Red Hat Enterprise Linux sources.

The RHEL is the enterprise-class operation system but with a paid subscription. CentOS developers use the RHEL source code and create a product very similar to it. The technical support for this is given only via web portals and community.

yum is the package manager for the CentOS. Anything that runs on is assured to run on the RHEL platform. CentOS images are one of the tops employed Operating Systems in the Azure Cloud and Amazon Cloud.

Since March 2004, CentOS Linux has been a community-supported distribution derived from sources freely provided to the public by Red Hat. As such, CentOS Linux aims to be functionally compatible with RHEL. We mainly change packages to remove upstream vendor branding and artwork. CentOS Linux is no-cost and free to redistribute.

CentOS Linux is developed by a small but growing team of core developers. The core developers are supported by an active user community, network administrators, managers, core Linux contributors, system administrators, and Linux enthusiasts worldwide.

CentOS Linux is a leading community platform for emerging open source technologies from other projects such as OpenStack. These technologies will be at the center of CentOS's multiple variations, as individual downloads or accessed from a custom installer.

History

• In May 2004, it is a 100% free operating system distribution based upon the Linux kernel. CentOS is derived from the Red Hat Enterprise Linux (RHEL) distribution. It exists to provide a free enterprise-class computing platform and maintain 100% binary compatibility with its upstream source, Red Hat.
• Before becoming known under its current name, CentOS originated as a build of CAOS Linux, started by Gregory Kurtzer.
• In June 2006, David Parsley, the primary developer of Tao Linux (another RHEL clone), announced the retirement of Tao Linux and its rolling into CentOS development. Tao users migrated to the CentOS release via yum update.
• In July 2009, it was reported in an open letter on the CentOS project web site that CentOS's founder, Lance Davis, had disappeared in 2008. Davis had ceased contribution to the project but continued to register for the CentOS domain and PayPal account.
• In August 2009, the CentOS team reportedly contacted Davis and obtained the centos.info and centos.org domains.
• In July 2010, CentOS overtook Debian to become the most popular Linux distribution for web servers, with almost 30% of all Linux web servers using it. But in January 2012, it lost that position to Debian once again.
  
• In January 2014, Red Hat announced that it would sponsor the CentOS project, helping to establish a platform well-suited to the needs of open source developers that integrate technologies and around the operating system.
• Ownership of CentOS trademarks was transferred to Red Hat. The CentOS head developers work as part of Red Hat's Open Source and Standards team, which operates separately from the Red Hat Enterprise Linux team.
• CentOS is one of the most popular Linux distributions in the hosting industry. Due to CentOS' binary compatibility with RHEL, it is highly compatible with most Linux software. Most hosting control panels use CentOS as the preferred Linux distribution.

Architecture

It also follows the same architecture as any other Linux distro and supports only x86-64 architecture, supporting both 32-bit and 64-bit systems.

• The bottom-most layer is hardware or physical devices such as a computer, storage, and network devices.
• On top of this sits the kernel, which is the core component of the OS, and it directly interacts with the hardware.
• On top of the kernel sits the shell, which acts as the interface between the user and the kernel.

These layers are the application layer that interacts with the shell and kernel to do some user-defined tasks. Applications include web browsers, file explorer, media player, text edition, etc.

Working of CentOS

Here are some commands which will help in working of CentOS, such as:

1. ls: This lists out the directory contents.
2. cd: This is used to change the directory or navigate a different folder from the current folder.
3. mv: This is the move command. It helps to move a file from one directory to a different location or rename a file.
4. man: This is the command to get manual about any other command used in the OS.
5. mkdir:This command is used to create new directories (and also subdirectories).
6. rmdir: This is the command to delete the directory. It will also recursively remove the files and folders in the mentioned directory.
7. touch: This command creates an empty file. This is also called the make file command.
8. rm: rm removes the files just like rmdir removes the directories.
9. locate:This command will help you to locate a file in the whole of storage.
10. clear:This is the command to clear the terminal screen.
11. sudo yum update:This will update all the installed packages.
12. sudo yum install <package name>: This command will install the mentioned package.

One can write the set of commands in a sequence of tasks to be done in a file with an extension. sh and execute them all at once by running the .sh file called 'shell script' by using the command sh <filename>.sh.

One can also create his self-defined commands in this shell scripting and use them for different purposes.

CentOS Versions

There is a delay in creating CentOS from RHEL, so it's essential to be mindful of CentOS Linux version numbering. We can find the latest version of CentOS in the CentOS release notes.

As of June 2020, CentOS version 8.2 is out. While individual patches often get included in the CentOS repos within 24 hours, on average, it takes about 42 days for a CentOS point release to follow an RHEL point release.

Red Hat released RHEL 8.2 on April 28, 2020. CentOS 8.2 released on June 15, an outstanding achievement considering all the world changes due to the COVID-19 pandemic.

There are some key differences between versions of CentOS Linux distributions, including CentOS 8.

Advantages

Below are some advantages of using the CentOS.

1. It is lightweight, reliable and fast.
2. It is free and open-source, and it is enterprise-grade.
3. Along with it, you will also get the open-source server software such as Apache Web, CUPS, MySQL, etc. and version control tools like git comes installed by default.
4. Excellent community support with the provision to directly report bugs to the bugs.centos.org.
5. Latest CentOS also includes hypervisor and virtualization technology such as Docker, oVirt, Xen, etc.
6. It shares almost 95% of the features which the commercial Red Hat Enterprise Linux has. And this is available for free.
7. Compared to other open-source and free Linux distros, CentOS is widely preferred for its stability and less frequent package updates.