!!! SHOULD USE PASSWORD !!!
Generate an SSH key, using PEM (and not the new default RFC4716):
ssh-keygen -m PEM -t rsa -b 4096 -C "email@example.com"
For an older key that needs to be converted to PEM, run this:
ssh-keygen -p -m PEM -f ~/.ssh/id_rsa
To copy the public key to the clipboard, do:
pbcopy < ~/.ssh/id_rsa.pub