How to set up an SSH key and use it to access a remote machine.

Generate Key

ssh-keygen

Copy the Key

ssh-copy-id [-p port_nbr] username@server_or_IP

So this may look like one of the below.

ssh-copy-id sftp@12.34.56.78
ssh-copy-id -p 2222 leethaxor@pwnnoobs.pro

Profit

Now you should be able to log in or copy files without needing to type a password.

ssh [-p port_nbr] username@server_or_IP
scp [-P port_nbr] username@server_or_IP:file_to_pull local_path_to_save
scp [-P port_nbr] local_path_to_send username@server_or_IP:remote_path_to_save