Linux is an open-source operating system similar to Windows and OS X that powers many servers, mobile phones, supercomputers, and other devices. It is developed collaboratively by thousands of developers from around the world, which helps spread costs and leads to software innovation. The document then discusses how to set up a Linux Samba server to allow file sharing with Windows machines and an HTTP server to host web pages. It provides step-by-step instructions for configuring the Samba and HTTP servers, including editing configuration files and changing directory permissions to enable file sharing between Linux and Windows systems.