> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.ex2.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# What is Linux?

## Linux operating systems 

Linux is a collection of open-source operating systems (OS). There is no single Linux operating system, but rather a set of different systems. Users can choose from a large group of Linux distributions, all offering different and unique experiences.

Linux is one of the most popular operating systems in the world. Web developers in particular have a penchant for it. Its open source nature allows you to adapt the OS to your needs and even collaborate with other users in its development.

The term Linux specifically refers to the kernel of the system, which is the core program of the operating system. There are however hundreds of unique Linux versions (called distributions).

Each distribution offers a unique experience. Some of them are focused on simple daily use, while others are optimized for safety. Linux is also a popular option for web hosting, because it is free and flexible.