SSH, which is an abbreviation for Secure Shell, is a network protocol which is used to transfer encoded data between a client and a hosting server, making it impossible for unauthorized parties to intercept any info. Many tech-savvy customers prefer SSH due to the better level of security. The connection is established and the commands are sent using a command line. The offered options depend on the type of web hosting service - on a shared server, for instance, files could be moved or deleted, databases could be imported and exported, and archives can be created or unpacked. On a virtual or a dedicated server, your choices are significantly more - the web server and the database server may be started/stopped/rebooted, server-side software may be installed and more. These things are not possible on a shared server, for the reason that full root access is required and all the other customers on that server would be affected. While SSH is employed predominantly with UNIX-like OSs, there are SSH clients for other OSs too - Windows, Mac OS, etc.