gpg --keyserver pgp.mit.edu --recv-keys [KEY_ID_2]
gpg --fingerprint [KEY_ID_2]
gpg --sign-key [KEY_ID_2]
#gpg --armor --output [KEY_ID_2]-signedBy-[KEY_ID].asc --export [KEY_ID]
#gpg --import [KEY_ID_2]-signedBy-[KEY_ID].asc
gpg --send-key [KEY_ID_2]