This tutorial is about SSH and SCP. You will learn how to connect to a remote host and how to copy between hosts. This tutorial also documents a few important differences between the commands.

Difficulty: Basic

Before we start: in this tutorial, you will come across both SSH and ssh. The difference is this: SSH is the general protocol, and ssh is the linux SSH client command.

SSH

SSH is some kind of an abbreviation of Secure SHell. It is a protocol that allows secure connections between computers. In this tutorial, we'll be dealing with the ssh command on Linux, the OpenSSH version. Most Linux distributions feature the OpenSSH client today, but if you want to be sure, have a look at the SSH manpage on your system. You can do this by typing:

Note: this should be done in a terminal. This tutorial assumes that you have some basic terminal knowledge, like knowing how to start a terminal session on your system and being familiar with the basic commands and syntaxes.

If it displays something like this

then you can be quite sure you're running the OpenSSH version. For more background information about SSH, see http://en.wikipedia.org/wiki/SSH.

The most simple case

In the most simple case, you can connect to a server that supports ssh with a syntax as short as this:

Note: If you do not have any ssh server nearby that you can access, you can also try this command with your own computer as a server. To do this, replace "serverToConnect" with "localhost".

Of course, serverToConnect should be replaced by a hostname or an ip address of the server you want to connect to. As you can see in the terminal snippet, I am logged in as user1. If you do not specify a username (I'll explain how to do that later in this tutorial), SSH will assume that you want to login with the username you're currently logged in with. So, in this case, SSH will try the username user1.

Also, you need to be sure that the server supports ssh connections. The default port the ssh client trıes to connect to is 22. You will find more regarding the SSH port further in this tutorial.