Reposync
From wiki
$ reposync --newest-only --repoid=rhel-7-server-rpms --download_path=/work/www/html/rhel7/main --downloadcomps --download-metadata
$ reposync --newest-only --repoid=rhel-7-server-rpms --download_path=/work/www/html/rhel7/main --downloadcomps --download-metadata