A brief introduction...Linux is a free and open source operating system. It is developed by Linus Torvalds, a programmer and the creator of the Linux operating system. Development of Linux originially started in 1991 and has quickly grown to be one of the most popular operating systems in the world.
The syntax of Linux commands are very similar to that of Unix. You'll find that in the tech world, that the Linux operating system is the most popular choice for servers. Although, Windows and MacOS can still be used as servers. A plethora of cybersecurity tools are generally designed for Linux. There are many Linux Distributions that you can use, the most popular one for cybersecurity is Kali Linux. It's advised that if you're new to Linux you use a distribution like Ubuntu.
Picture of Linus Torwalds, the creator of Linux