"SSH is typically used to log into a remote machine and execute
commands. However, there are a wide variety of other uses for SSH.
For example, it supports TCP port forwarding whereby an SSH server
can secure otherwise insecure protocols, as well as X11 forwarding
which offers a secure way to use graphical applications over a
network. Other common uses of SSH include tunnelling and
transferring files across machines using SSH file transfer (SFTP)
or secure copy (SCP) protocols.
"Anyone who needs to administer a Linux computer will understand
the significance of being able to securely log into a machine and
perform tasks given that any program that allows incoming
connections without the ability to encrypt it's data increases the
risk to a site."