This article covers how to enable ssh passwordless login using ssh-keygen and ssh-copy-id. In fact, SSH (Secure SHELL) can be used to transfer files from one computer to another computer over the network using a secure copy (SCP) Protocol.
ssh-keygen creates the public and private keys. ssh-copy-id copies the local-host's public key to the remote-host's authorized_keys file. ssh-copy-id also assigns proper permission to the remote-host's home, ~/.ssh, and ~/.ssh/authorized_keys.