I have an Ubuntu Linux on a VMWare running and I've installed RPM Package Manager. However when I try to query all packages using the
rpm -qa command, I don't get any results returned.
How can I fix this?
I'm a Linux beginner, BTW.
RPM is the Redhat Package Manager.
Ubuntu is based on Debian and uses APT.
While you can install RPM in Ubuntu, I think you would be better off to stick with Ubuntu's package manager that uses the DEB package format. To quote from the Ubuntu Synaptic output,
On Debian and derived systems it is recommended to use "alien" to convert RPM packages into .deb format instead of bypassing the Debian package management system by installing them directly with rpm.
Here is a link to how to use Alien.
According to Wikipedia, the RPM database is located in /var/lib/rpm and it stores information about packages installed under RPM. You may have gotten no output because there were no packages installed under RPM.