OpenSUSE install lsof package to get rid of 'zypper ps' errors

Originally published at: https://www.cyberciti.biz/faq/opensuse-install-lsof-package-to-get-rid-of-zypper-ps-errors/

I run the following command but getting error:</br/>
$ zypper ps</br/>
    Check failed:
    Please install package ‘lsof’ first.
</br/>
How do I fix and how can I use the ‘zypper ps’ on OpenSUSE 15.1/15.2 to find out if system reboot requires or not?