PPK to PEM MAC

ppk-to-pem.sh

#You can also convert the key using putty for Mac via port or brew
sudo port install putty

#or
brew install putty

#This will also install puttygen. To get puttygen to output a .PEM file:
puttygen privatekey.ppk -O private-openssh -o privatekey.pem

#Once you have the key, open a terminal window and:
ssh -i privatekey.pem user@my.server.com

#The private key must have tight security settings otherwise SSH complains. Make sure only the user can read the key.
chmod go-rw privatekey.pem