Get public key from pemfile handy for AWS EC2 Users

See the question on stackoverflow:
https://stackoverflow.com/questions/38401719/how-do-i-get-the-public-key-of-an-pem-file

$ cd $HOME/.ssh

$ chmod 600 somekey.pem

$ ssh-keygen -f somekey.pem -y > somekey.pub

Now add pem key's public key to a new server:

$ ssh-copy-id -i $HOME/.ssh/somekey.pub someuser@yourserver.com