###ssh-copy-id
####Mac :
brew install ssh-copy-id
####Synopsis: ssh-copy-id [-i filename] [user@]machine
####Example:
ssh-copy-id -i mykey.pub root@1.2.3.4
If the -i option is given then the identity file (defaults to ~/.ssh/id_rsa.pub) is used, regardless of whether there are any keys in your ssh-agent.
Once it has one or more fingerprints (by whatever means) it uses ssh to append them to ~/.ssh/authorized_keys on the remote machine (creating the file, and directory, if necessary)
####References:
ssh-copy-id