Ubuntu, being a distribution derived from Debian, uses installer packages with extension .deb whereas other distributions like Fedora, CentOS, OpenSuse, Mandriva ... etc, use .rpm installers.
Many packages on the internet are only packaged in rpm.
If we have a system based on Debian as it may be Ubuntu it is possible to install these packages rpm in the system without harming it.
alien
but definitely not recommended. Most if not all generic software available as rpm is also packaged as deb. As a matter of fact it's much easier to find debs than rpms. Most software in rpm only is intended to a specific distro only. There's no point in trying to install it in Ubuntu. – Jan 15 '17 at 17:16.rpm
. In that case, install as suggested here. – Jan 15 '17 at 18:39