RHEL 8 update installed packages for security

The procedure to install updates on RHLE:

1. Open the terminal app.
2. For remote server log in using the ssh command: ssh user@server-name-here.
3. Show information about update advisories, run: sudo yum updateinfo
4. Issue the command sudo yum update to refresh package database and install updates.
5. Reboot the system if kernel was updated by typing sudo reboot command.

Let us see all steps in details.

Find out info about available security-related updates

It is a good idea to find out if there any updates available for the box. Hence, run the following command:
sudo yum updateinfo
Sample outputs:

Last metadata expiration check: 0:17:14 ago on Monday 16 September 2019 07:01:29 PM UTC.
Updates Information Summary: available
     6 Security notice(s)
         6 Important Security notice(s)
    10 Bugfix notice(s)

Want to see a list of the updates on screen? Try the following command along with grep command:
sudo yum check-update
sudo yum check-update | more
sudo yum check-update | grep bash
sudo yum check-update

Before you apply updates please note down Linux kernel version, run:
uname -mrs
Sample outputs:

Linux 4.18.0-80.7.2.el8_0.x86_64 x86_64

How to install updates via yum command line for RHEL 8

Open up a terminal application or log in using ssh. Run the yum command to upgrade all installed packages on Red Hat Linux system:
$ sudo yum update

One can only apply security related updates to the machines, run:
sudo yum --security update

How do I update a single package?

Run the following command:
sudo yum update pkg_name
sudo yum update bash
It is also possible to install all updates except kernel and bash packages as follows:
sudo yum -x 'kernel*' -x 'bash*' update
The -x option exclude packages specified given name. See “Force yum update Command To Exclude Certain Packages” for more info.

Reboot the Linux system

You must reboot system when RHEL 8.x Linux kernel gets updated, run:
sudo reboot
Verify Linux kernel version and list updates:
uname -mrs
sudo yum updateinfo

Conclusion

You learned how to install the software update for all installed packages using the GUI and CLI methods on RHEL 8.x based systems. See RHEL yum man page for more information.