1) Login to your shell account

2) Use –export option to export your public key in text file
$ gpg –export –a > my.key
OR
$ gpg –export -a | mail -s “My key” [email protected]

Where
-a –armor : Create ASCII armored output.
–export : Export the key for sharing

First command write output to file my.key and second directly sends an email to your friend. Once my.key delivered to friend, he/she need to import it using the following command (aka adding keys to your keyring):
$ gpg –import my.key