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.
Despite 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 should not be used to replace important system packages, like sysvinit, shared libraries, or other things that are essential for the functioning of your system. Many of these packages are set up differently by Debian and Red Hat, and packages from the different distributions cannot be used interchangably. In general, if you can't uninstall the package without breaking your system, don't try to replace it with an alien version.
News
alien 8.81 released with these changes
- Avoid uninitialized value warning when debian/rules fails to run due to alien being run in a noexec directory. Closes: #579216
- Prevent DESTROY stomping on alien's exit code sometimes.
- Support extracting lzma compressed RPMs. (Patch by unnamed person on some bug tracking system I don't frequent.)
- Suggest lzma. If not installed, alien will still fail to decompress RPMs using it, but will support most rpms, which are not.
- Fix precedence problem that prevented alien from preserving permissions of suid/sgid binaries that are not owned by root. (Patch by Duane Waddle, on a bug tracking system I don't frequent, that was about the "expire" it 4 days from now. We got lucky Duane, but please use the Debian BTS next time!)
- Support RPMs containing ghost files. (Patch by Ben Webb, who would get his patches applied quicker if he actually communicated them to the program's author.)
alien 8.80 released with these changes
- Support querying rpm LICENSE field. (Alexey Khoroshilov)
Downloading alien
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
Other things you'll need
To use alien, you will need several other programs. 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 its 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.
Attention, all linux users who don't use Debian: Bruce S. Babcock has put together a package of all the extra files you need to use alien on a non-Debian distribution. It's called "alien-extra", and you can download it from his ftp site.
I've blogged a few times about alien. Alien use patterns examines who I think is using alien now, and this post gives some historical background.