To apply package updates from the Red Hat Network (RHN) on a Red Hat Enterprise Linux (RHEL) system, you will need to have a valid subscription and set up the RHN package repositories on your system.
To set up the RHN package repositories, you will need to use the subscription-manager tool. First, register your system with RHN by running the following command and following the prompts:
sudo subscription-manager register
Next, attach your system to a subscription pool by running the following command and specifying the pool ID:
sudo subscription-manager attach --pool=POOL_ID
Replace POOL_ID with the ID of the subscription pool that you want to use. You can find the pool ID on the RHN website or by running the subscription-manager list --available command.
Once your system is registered and attached to a subscription pool, you can enable the RHN package repositories by running the following command:
sudo subscription-manager repos --enable=rhel-8-for-x86_64-baseos-rpms
This will enable the base package repository for RHEL 8 on a 64-bit system. If you are using a different version of RHEL or a different architecture, you will need to use the appropriate repository name. You can find the available repository names by running the subscription-manager repos --list command.
Once the RHN package repositories are enabled, you can update your system by running the following command:
sudo dnf update
This will update all installed packages from the RHN repositories. You can use the --refresh option to check for new updates and the --assumeyes option to automatically answer "yes" to any prompts.
sudo dnf update --refresh --assumeyes
Keep in mind that you will need to have root privileges (or be a member of the sudo group) in order to update packages using dnf.
It is recommended to regularly update your system to ensure that you have the latest security patches and fixes installed. You can use the dnf update command to update all installed packages, or use the --security option to update only packages with security updates.