Import and Export GnuPG key

Listing the key.

$ gpg --list-keys
/home/user/.gnupg/pubring.gpg
--------------------------------
pub 1024D/ABCDFE01 2008-04-13
uid firstname lastname (description)
sub 2048g/DEFABC01 2008-04-13

Export key

$ gpg --output mygpgkey_pub.gpg --armor --export ABCDFE01
$ gpg --output mygpgkey_sec.gpg --armor --export-secret-key ABCDFE01

Import key

$ gpg --import mygpgkey_pub.gpg

$ gpg --allow-secret-key-import --import mygpgkey_sec.gpg