private-keys-v1.d

[Long Si]

Hi

Before migrating to a new system, I exported my GPG secret keys and
then imported them. Both "gpg -k" and "gpg -K" shows both the public
and private keys are imported properly. However, I note my
".gnupg/private-keys-v1.d" directory is empty, and I am unable to sign
my emails with Evolution client, it kept reporting "secret keys not
found". Fortunately, I kept a copy of my old directory and copied the
two (.key) files over and now things are okay. Thus, I like to ask how
do I generate the (.key) files from my exported, armoured text file
created by "gpg --export-secret-keys"? Isn't creating a backup of my
secret key enough to recreate the rest of the necessary files?

Regards