Convert 32bit RPM to DEB 64bit: A Practical Guide

To convert a 32-bit RPM package to a 64-bit DEB package, you cannot directly convert the architecture; you must first convert the RPM to a DEB and then rebuild or repackage it for 64-bit, which usually requires the source code or a 64-bit version of the software. This article explains the steps, tools, and limitations involved in this process.

Understanding RPM and DEB Formats

RPM (Red Hat Package Manager) and DEB (Debian Package) are two different package management systems used by Linux distributions. RPM is used by distributions like Fedora, CentOS, and openSUSE, while DEB is used by Debian, Ubuntu, and their derivatives. Both formats are essentially archives that contain the program files, metadata (like version, dependencies), and installation scripts. The key difference is the structure and the tools used to handle them. Converting between them is not a simple rename; it requires translating the metadata and repackaging the files.

Why Architecture Matters: 32-bit vs 64-bit

Architecture refers to the processor’s instruction set. A 32-bit (i386, i686) package contains machine code that runs on 32-bit processors, while a 64-bit (amd64, x86_64) package contains code for 64-bit processors. A 64-bit system can often run 32-bit applications if the necessary 32-bit libraries are installed, but a 32-bit package cannot run natively on a 64-bit system without those compatibility layers. Simply converting the package format does not change the architecture; the binary code inside remains 32-bit. To get a true 64-bit DEB, you need a 64-bit build of the software.

Tools for Converting RPM to DEB

Several tools can assist in converting an RPM to a DEB, but they all have the same limitation: they do not change the architecture.

alien: The most common tool. It converts between RPM, DEB, and other formats. It can convert a 32-bit RPM to a 32-bit DEB (i386). To get a 64-bit DEB, you would need a 64-bit RPM.
fpm: A more flexible tool that can create packages from various sources, including RPMs. It can also repackage, but again, it does not recompile code.
dpkg-deb: The low-level Debian package tool. You can manually extract an RPM and use dpkg-deb to build a DEB, but this is tedious and error-prone.

Step-by-Step: Converting a 32-bit RPM to a 32-bit DEB

If you have a 32-bit RPM and your system is 32-bit, or you want a 32-bit DEB, here is the typical process using alien:

Install alien: sudo apt install alien (on Debian/Ubuntu).
Run the conversion: sudo alien --to-deb your-package.rpm
The output will be a .deb file with the same architecture (e.g., i386).
Install it with sudo dpkg -i your-package.deb.

If you need a 64-bit DEB, you must find a 64-bit RPM of the software, or better, a native 64-bit DEB. If only a 32-bit RPM exists, you might be able to run it on a 64-bit system by enabling multiarch and installing 32-bit libraries, but the package itself will remain 32-bit.

Common Problems and Limitations

Converting packages is not always smooth. Here are common issues:

Dependencies: The DEB may depend on libraries that are not available in your distribution’s repositories, or the names differ between RPM and DEB worlds.
Scripts: Pre- and post-installation scripts may be written for RPM-specific commands (like update-alternatives vs alternatives), causing failures.
Architecture mismatch: As noted, a 32-bit package will not magically become 64-bit. You will get an i386 DEB, which may not install on an amd64 system unless you enable multiarch.
File paths: Some packages assume certain paths (e.g., /usr/lib vs /usr/lib64) that differ between distributions.

Alternatives to Conversion

Instead of converting, consider these alternatives:

Find a native 64-bit DEB: Check the software’s official website or a PPA (Personal Package Archive).
Compile from source: If source code is available, compile it on your 64-bit system to produce a native 64-bit binary.
Use a container or VM: Run a 32-bit environment (like a Docker container with i386 image) to use the 32-bit package.
Use a compatibility layer: On Debian/Ubuntu, you can enable multiarch and install the 32-bit libraries needed, then install the 32-bit DEB.

Frequently Asked Questions

Can I convert a 32-bit RPM to a 64-bit DEB directly?
No. The architecture is determined by the compiled binary, not the package format. You would need a 64-bit build of the software.

Will alien convert the architecture?
No. Alien only changes the package format, not the architecture. A 32-bit RPM becomes a 32-bit DEB.

What if I install a 32-bit DEB on a 64-bit system?
It may work if you enable multiarch and install the required 32-bit libraries. Otherwise, it will fail with an architecture mismatch error.

Is there a way to make a 32-bit package run on 64-bit without conversion?
Yes, you can use multiarch on Debian/Ubuntu or install 32-bit compatibility libraries on other distributions. The package does not need to be converted, just installed with the right support.

What is the best tool for conversion?
Alien is the most straightforward for simple conversions. For more complex repackaging, fpm offers more control.

Can I convert a DEB back to RPM?
Yes, alien can do that too, but the same architecture limitations apply.

Conclusion

Converting a 32-bit RPM to a 64-bit DEB is not a single-step process. The format can be converted, but the architecture cannot be changed without recompiling. Always look for a native 64-bit package or compile from source to ensure compatibility and stability. If you must use the 32-bit package, consider multiarch or virtualization.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

More cards in this drawer

The whole Numbers and Powers drawer →