Linux is a widely used open source operating system across the globe. Many of our modern day computers, mobile phones, virtual games, social media applications, smart TVs, and several other useful applications / solutions run on linux operating systems. Linux OS is faster as well as more reliable than its competitors like Microsoft Windows, MacOS, Android, etc.
Linux is free and more importantly it is open-source released under GNU General public license (GPL), which means anyone can view, modify, and test as per requirement. Linux was first developed by Linus Benedict Torvalds, a Finnish-American software engineer. While he was studying at University of Helsinki, he wanted to design a free, open source operating system as an alternative to MINIX, which was an UNIX operating system. Linux and Unix are similar. The heart of the operating system in Kernel which acts as an interface between user and hardware. The major difference is that the UNIX operating system needs its own hardware from the vendor and it is not compatible with other vendors. For instance, Solaris OS runs on Oracle hardware, HP-UX (Hewlett Packard Unix) OS runs only on HP (Hewlett Packard) hardware, AIX is compatible only with IBM servers, etc. However, Linux is compatible with most of the hardware and does not need to have its dedicated servers from the vendors. There are many linux distro (distribution) till this date which are managed by the Linux community. Some major commercial linux distros are Ubuntu, RedHat Enterprise Linux, and SuSE Linux. The popular community driven distro are Debian, CentOS, Gentoo Linux, etc.
Pros of Linux OS:
1. This is open-source, which makes it available for all users to view, modify and enhance the code as per need.
2. Besides commercial distros, most community distro of linux are free.
3. It is faster, more secure, and handles high volumes of users.
4. It takes less space as many linux distro can be installed in as little as 128 MB RAM.
5. It runs on almost every platform.
6. It is community driven and has excellent community support.
7. It can be installed in very less time.
8 .Linux has both command-line interface as well as graphical user interface (GUI).
Why do we need to learn Linux ?
Linux OS skill is a must for IT administrator, System Administrator, Linux Administrator, DevOps Engineer, System Engineer and several other technology professionals. Myriad or almost all applications as we know that have touched human life are based on some flavor of linux OS. It can also be said that it is really hard to replace Linux or might take hundreds of years to find its alternative. It is a fact that everything from small devices like our cell phones to complex supercomputers, Cloud technology, etc leverages atleast some version of Linux operating system. So, yeah it is nearly impossible as of now to replace linux.
Architecture of linux
The architecture of linux consists of these layers:
1. Hardware layer:
2. Kernel
3. Shell
4. System Utilities
Hardware Layer
This layer consists of all pheripheral components such as RAM, Processor, Disk drives, motherboard, etc which are connected to a computer.
Kernel
It is a core components of a linux operating system which manages computer hardware recources. Kernel is the first program which gets loaded when OS starts which further manages resources and ends once OS is stopped. Kernel acts as an interface user and hardware. It allows multiple applications to share hardware resources of a computer by providing access to CPU, memory, storage, etc.
There are many functions of Kernel. Some of them are listed below:
- Device management
- Resource management
- Memory management
- Access control resources
Shell
This is an interface between user and Kernel which interpret users input as an command and pass it to kernel which further manages resources. Linux shell allows users to input commands. In linux, shell is a command line interface that accpects lines of texts and converts those input as instruction to kernel to execute certain tasks. Kernerl receives it and executes it. So, we can leverage shell to execute programs and utiliies on the kernel.
Linux Utilites
In a simple word, a linux system utility is a set of simple shell script commands which performs specific job. Linux utilities runs on a command line and Graphical user interface (GUI). GUI is an abstratcion of a command-line. Some common linux utilities are ls, pwd, cd, top, iostat, vmstat, etc.
How to download linux ?
Since linux is open-source, there are many linux distros which are free to download. Some freee linux distros are CentOS, Fedora, Debian, etc. Latest iso can be downloaded from their official websites.
Some sources are listed below:
CentOS: https://www.centos.org/download/
Debian: https://www.debian.org/distrib/
Fedora: https://getfedora.org/
Note: You will need to purchase enterprise edition of RedHat, Ubuntu, SuSE Linux, etc. This is beacuse enterprise edition provides many additional features such as enhanced security as well as excellent support.
What are key repsonsibilities of Linux System Administrator ?
Some of the major responsibilities of Linux System administors are following:
1. Create username and passwords for the users.
2. Modify permission of the file.
3. Install patches on a regualr basis to fix bugs.
4. Running backups
5. Mainataing user accounts
6. Perform Performance and Kernerl Tuning.
Relevant Certifications
Since Linux is a open source platform, you can easily pick any destros and start learning. However, Red Hat and SuSE Linux offers certifications of its enterprise edition on various fields such as RHCSA (RedHat Certified System administrator), RHCSE (RedHat Certified System Engineer, etc.).
You can visit their official page for more information on certifications. Some pages are listed below
SuSE: https://www.suse.com/training/exam/
Red Hat: https://www.redhat.com/en/services/training-and-certification