Deb packages are the Debian / Ubuntu equivalent of a Windows MSI file. They package up the required files for a application and provide a convenient way to distribute and install it.
However some more generic applications that work across many distributions, especially Red Hat Linux, come in a RPM file. RPM files are not natively able to run under a Debian version of Linux like Ubuntu. These means that you need some way of running it under Ubuntu. Enter Alien!
Alien is a piece of free open source software that allows you to convert RPM, SLP, TGZ, and PKG file formats to Deb (and also to one another but if you’re using Ubuntu then you want *.deb).
To install Alien you have (as you do most of the time) two choices. Either use the Synaptic Package Manager (SPM) or the Command Line Interface (CLI). At the time of posting the latest version in the repositories is 8.73.
To install via SPM search for the term alien and it should be the third option. Right click alien and select Mark for installation and then click Apply
To install via CLI, fire up the terminal and use the command sudo apt-get install alien type in your root password when prompted and let Ubuntu sort out the rest.
Once it’s installed fire up the Terminal (if you haven’t already to install Alien) and enter the command sudo alien -d name_of_package.rpm This will convert the RPM file to a Deb file. If you use the -i switch so sudo alient -d -i name_of_package.rpm it will generate and install the Deb package.
There other options that can be activated using other switches, these can be found using
alien --help