References:
Installed by default
sudo pacman -S --needed gnupg
Config directory
~/.gnupg/
Import key (replace gpg_key.asc)
gpg --import gpg_key.asc
List public keys (or -k)
gpg --list-public-keys
List secret keys (or -K)
gpg --list-secret-keys
Edit key (replace user-id)
gpg --edit-key user-id
Set trust level to 5:
gpg> trust
gpg> 5
gpg> quit