root@kali:~$ gpg --list-keys
~/.gnupg/pubring.gpg
-----------------------------
pub   rsa4096 2020-02-03 [expires: 2022-02-02]
      0xB1A97DA287FBBF98
uid           Andreas Schreiber

root@kali:~$ gpg --fingerprint
pub   rsa4096 2020-02-03 [expires: 2022-02-02]
  Key fingerprint = 67DE 78EC B016 9FEF 2EA4  0B26 B1A9 7DA2 87FB BF98

root@kali:~$ mail -s "Hi!" andi@schre1ber.de ‹ /dev/null>