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5.5. Coexistence with Other Packaging Systems

Debian packages are not the only software packages used in the free software world. The main competitor is the RPM format of the Red Hat Linux distribution and its many derivatives. Red Hat is a very popular, commercial distribution. It is thus common for software provided by third parties to be offered as RPM packages rather than Debian.
In this case, you should know that the program rpm, which handles RPM packages, is available as a Debian package, so it is possible to use this package format on Debian. Care should be taken, however, to limit these manipulations to extract the information from a package or to verify its integrity. It is, in truth, unreasonable to use rpm to install an RPM on a Debian system; RPM uses its own database, separate from those of native software (such as dpkg). This is why it is not possible to ensure a stable coexistence of two packaging systems.
On the other hand, the alien utility can convert RPM packages into Debian packages, and vice versa.
$ fakeroot alien --to-deb phpMyAdmin-2.0.5-2.noarch.rpm 
phpmyadmin_2.0.5-2_all.deb generated
$ ls -s phpmyadmin_2.0.5-2_all.deb
  64 phpmyadmin_2.0.5-2_all.deb
You will find that this process is extremely simple. You must know, however, that the package generated does not have any dependency information, since the dependencies in the two packaging formats don't have systematic correspondence. The administrator must thus manually ensure that the converted package will function correctly, and this is why Debian packages thus generated should be avoided as much as possible. Fortunately, Debian has the largest collection of software packages of all distributions, and it is likely that whatever you seek is already in there.
Looking at the man page for the alien command, you will also note that this program handles other packaging formats, especially the one used by the Slackware distribution (it is made of a simple tar.gz archive).
The stability of the software deployed using the dpkg tool contributes to Debian's fame. The APT suite of tools, described in the following chapter, preserves this advantage, while relieving the administrator from managing the status of packages, a necessary but difficult task.