macbook generate .pem code example

Example: macbook generate .pem

brew <upgrade|install> openssl 
openssl genpkey -algorithm RSA -aes-256-cbc -outform PEM -out private_key.pem -pkeyopt rsa_keygen_bits:2048
chmod 0400 private_key.pem
ssh-keygen -e -f private_key.pem > public_key.pem