SSH, which is an abbreviation for Secure Shell, is a network protocol that is used to exchange encrypted data between a client and a hosting server, which makes it impossible for unauthorized parties to intercept any information. Many tech-savvy customers prefer SSH because of the improved level of security. The connection is established and the commands are delivered via a command line. The accessible options depend on the type of hosting service - on a shared server, for instance, files may be transferred or deleted, databases may be imported and exported, and archives can be set up or unpacked. On a virtual or a dedicated server, the choices are a lot more - the web server and the database server may be started/stopped/rebooted, server-side software can be installed and much more. These things aren't possible on a shared server, since full root access is needed and all the other clients on that server will be affected. Though SSH is used predominantly with UNIX-like OSs, there are SSH clients for other OSs too - Windows, Mac OS, etc.