SSH, which is an abbreviation for Secure Shell, is a network protocol that is used to transfer encrypted data between a client and a hosting server, making it impossible for unauthorized parties to intercept any information. Many tech-savvy users prefer SSH due to the improved security level. The connection is created and the commands are sent using a command line. The offered options depend on the type of hosting service - on a shared server, for instance, files could be relocated or deleted, databases can be imported and exported, and archives could be created or unpacked. On a virtual or a dedicated server, your options are significantly more - the web server and the database server could be started/stopped/rebooted, server-side software could be set up and a lot more. These things aren't possible on a shared server, due to the fact that full root access is required and all the other clients on that server will be affected. While SSH is used mainly with UNIX-like OSs, there are SSH clients for other OSs too - Windows, Mac OS, etc.