Alien is a program that converts between the rpm, dpkg, stampede slp, and slackware tgz file formats. If you want to use a package from another distribution than the one you have installed on your system, you can use alien to convert it to your preferred package format and install it.
At the time you want to install a program meanwhile the only package available is from another Linux distribution. For an example, your Linux package is Fedora Red Head Package (.rpm) but you are using Ubuntu which use Debian Package (.deb) then you will need Alien.
*Notice: Due to the large version number, alien is still (and will probably always be) rather experimental software. It has been used by many people for many years, but there are still many bugs and limitations.*
Alien is a perl program, and requires perl version 5.004 or greater.
To convert packages to or from rpms, you need the Red Hat Package Manager; get it from RPM website.
If you want to convert packages into debian packages, you will need the dpkg, dpkg-dev, and debhelper packages, which are available on the Debian packages site. You’ll also need gcc, and make.
More details HERE.
Alien is available as the alien package in Debian.
Currently the best place to download the tarball is from http://packages.debian.org/unstable/source/alien
Its git repository is git://git.kitenet.net/alien
$ sudo apt-get install alien
(Other Linux Distribution need to download the above tarball)
$ alien [options] file
(The most important options, for most users, are -r, -d and -t for .rpm (Red Hat), .deb (Debian) and .tgz (Slackware) package output format respectively.)
You can convert also from DEB to RPM or the other way around. Some work perfectly. But not all packages can be converted correctly. Some may still produce errors.
Convert from RPM to DEB (alien -d)
$ sudo alien -d xxxxxx.rpm
Convert from DEB to RPM (alien-r)
$ sudo alien -r xxxxxxx.deb
In an era of “double click to install” working with package installers and tools such as Alien can save valuable time of which some can be dedicated to then customizing the underlying configuration file(s). What do you think about alien?