Useful Commands
SSH Login via Private Key (default private key file: id_rsa)
ssh <YOUR_USERNAME>@<YOUR_SERVER_HOST>
SSH Login via Custom Private Key
ssh <YOUR_USERNAME>@<YOUR_SERVER_HOST> -i <YOUR_PRIVATE_KEY_PATH>
Setup Public Key via ssh-copy-id (for macOS)
# install ssh-copy-id (first time)
brew install ssh-copy-id
# setup the key
ssh-copy-id <YOUR_USERNAME>@<YOUR_SERVER_HOST>