When you create or generate a new GPG or GnuPG key pair, it is stored in your key ring. Keys stored within the key ring can be listed using using the command as below in the Linux terminal.
$ gpg --list-secret-keys <enter>
/home/user/.gnupg/secring.gpg
------------------------------
sec 4096R/3949C65A 2014-11-28 [expires: 2015-11-28]
uid John N. Doe <john.doe@emaildomain.com>
ssb 4096R/F0F04E4E 2014-11-28
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