List keys

gpg --list-keys

e.g.,

$ gpg --list-keys
/home/kevin.qiu/.gnupg/pubring.gpg
----------------------------------
pub   4096R/D39DC0E3 2014-10-28
uid                  Michal Papis (RVM signing) <mpapis@gmail.com>

pub   2048R/26DF03A6 2018-01-10
uid                  Kevin Qiu <kevin.qiu@points.com>
sub   2048R/E82277EE 2018-01-10

pub   4096R/A0FFD6F6 2015-04-11 [expires: 2025-04-08]
uid                  keybase.io/rajitha <rajitha@keybase.io>
sub   4096R/99E563E3 2015-04-11 [expires: 2025-04-08]

Export to a file

gpg --armor --export <keyid> > <email>.gpg.asc

Import from a file

cat <email>.gpg.asc | gpg --import