Secure Shell, also known as SSH, is a cryptographic network protocol used to execute commands on a remote server or to exchange data between a server and a client. Given that the info exchanged by the 2 sides is encrypted, a third party won't be able to intercept it, which makes SSH a preferred means of managing a hosting account. The commands which can be executed are determined by the type of hosting service. On a shared server, for example, the choices are limited since you'll not have root access to the web server, so you can only create/move/delete files, create and unpack archives, import and export databases, and so on. They're all actions that are performed inside the shared hosting account and don't need a higher level of access. Using a virtual or a dedicated server, you will have the option to set up server-side software or to restart the web server or just a particular service (web server, database server, etc.). SSH commands are submitted via a command line, and if you don't use a UNIX-like OS, there are tons of applications for other OSs, you can employ to connect to the remote web server as well.