gpg -k
gpg -K

gpg --verify gnupg-2.2.21.tar.bz2.sig gnupg-2.2.21.tar.bz2

gpg --edit-key 0x12345678
gpg> key 0
gpg> expire
gpg> key 1
gpg> expire
gpg> save

gpg --armor --export mail@example.com > example-key.asc
gpg --output public.pgp --armor --export username@email
gpg --output private.pgp --armor --export-secret-key username@email