list keys

list all keys currently in keyring:

gpg --list-keys


and to import private and public keys in binary or ASCII format:

gpg --import xyz.key


To export your private key in ASCII format, e.g. to send it via E-Mail:

gpg --export-secret-key --armor you@dom.tld > private.key

To export your public key, again in ASCII format:

gpg --export --armor you@dom.tld > public.key

If you don’t need it in ASCII format use for the private:

gpg --export-secret-key you@dom.tld > private.key

and the public:

gpg --export you@dom.tld > public.key