SSH allows you to connect to a shell on a remote computer.
[user@localhost ~]$ ssh username@yourserver
Use -p to set the port.
[user@localhost ~]$ ssh -p 123 username@yourserver - connects using port 123.
You can also use scp to securely transfer files.
scp examplefile yourusername@yourserver:/home/yourusername/
This example sends examplefile from the directory you're currently in to /home/yourusername/ on yourserver
Note that scp uses
-P to specify the port.
To download a file from a remote server to your local computer:
scp email@example.com:/remote/file.txt /home/user/Downloads/
ssh keys are used to connect to an ssh server without a password.
Step 1: Create a key-pair on the client machine
ssh-keygen -t rsa
After you enter the above command, ssh-keygen will ask you where you want to store the key. You can just press ENTER to accept the default location.
Next, it will ask you to enter a passphrase. You can either enter a passphrase, or press ENTER to not use a passphrase. (Note that you don't need a pass-phrase, but if you don't use one, anyone that somehow gets a copy of the key can get into your server.)
SSH keygen will spit out a bunch of stuff, and you're done with step 1.
Step 2: Copy the public key to the server
This will copy the public key over to the server. Now try to connect via SSH, and it should connect without a password (unless you entered a pass-phrase. In that case, you need to enter the pass-phrase to connect.)