Secure Shell, better known as SSH, is a cryptographic network protocol employed to execute commands on a remote server or to exchange information between a web server and a client. Because the data exchanged by the 2 sides is encrypted, a third party can't intercept it, which makes SSH a preferred means of handling an Internet hosting account. The commands that may be executed depend on the type of hosting service. On a shared hosting server, for instance, the alternatives are limited because you will not have root access to the server, so you could only create/move/delete files, create and unpack archives, import and export databases, etcetera. They are all actions which are executed within the shared hosting account and don't need a higher level of access. By using a virtual or a dedicated server, you will be able to set up server-side software or to restart the machine or just a certain service (web server, database server, etc.). SSH commands are submitted through a command line, and if you don't employ a UNIX-like Operating System, there are plenty of applications for other OSs, that you can employ to connect to the remote web server as well.