UNIX/MAC:
You can find respectively these two keys in files public_key_sender.asc and private_key_sender.asc
if you execute the following code (the -a or --armor option in gpgis used to generate ASCII-armored key pair):
gpg --gen-key # generates the key pair
gpg --full-gen-key
gpg --list-keys # get your PubKeyId (this value is used in the line below)