Secure Shell, better known as SSH, is a cryptographic network protocol used to execute commands on a remote web server or to exchange data between a server and a client. As the info exchanged by the two sides is protected, a 3rd party simply cannot intercept it, which makes SSH a preferred means of managing a web hosting account. The commands which can be executed depend on the type of hosting service. On a shared hosting server, in particular, the possibilities are limited as you will not have root access to the website hosting server, so you can just create/move/delete files, create and unpack archives, export and import databases, etc. These are all actions that are executed in the shared hosting account and don't require a higher level of access. Using a virtual or a dedicated server, you'll have the ability to set up server-side software or to restart the web server or just a certain service (web server, database server, etc.). SSH commands are submitted through a command line, but if you don't employ a UNIX-like OS, there are a number of applications for other OSs, you can use to connect to the remote server as well.