The world of linux is free and opensource.

Linux is a family of open source operating systems based on the Linux kernel, first released on September 17, 1991, by Linus Torvalds.

Origenaly developed for personal computers based on intel x86 architecture. This is the leading operating system on servers. Over 96% of the top one million web servers are based linux.

Distribution typically include linux kernel and supporting software and libraries.

Types of usages

There are two types of use for linux

Server
&
Desktop

Popular linux distributions are Debian, Fedora, Ubuntu.
Commercial distributions are Red Hat Enterprise & SUSE Linux Enterprise Server.

Anyone can own a linux operating system. Almost all types of hardware can run linux.

This is the most prominent example of free and open source software collaboration. The source code of linux may be modified and distributed both commercially and non-commercially.