Converting EC2 pem file to ssh public key

EC2 supplies an OpenSSL encrypted "pem" private key. Sometimes you just need the ssh public key version of this file.

There are a few ways to do this using openssl and other tools, but I prefer using ssh-keygen to create a public key from a private key.

 ssh-keygen -y -f yourprivatekey.pem  

This will print out the public key from any given private key. Works with EC2 pem files.

Just drop the output of this command into ~/.ssh/authorized_keys and you should be good to go!