CPIO Converter
FileFlip converts CPIO files into 11 other formats entirely inside your browser, using libarchive compiled to WebAssembly. The CPIO file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. There is no file-size limit and no account to create.
How do I convert a CPIO file?#
- Drop your CPIO file onto the converter at the top of this page, or click it to pick one from your computer.
- Choose the format you want out of it. FileFlip downloads the engine that conversion needs, once, and your browser caches it.
- Conversion starts the moment you pick the format, and the result is yours to download. The work happens in this tab, so nothing is uploaded and nothing is queued.
Is it safe to convert CPIO files online?#
Yes, because nothing is uploaded. FileFlip converts CPIO files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What happens to a CPIO file#
FileFlip converts CPIO into 11 formats with libarchive, all of it inside the browser tab. Each conversion below names the engine it uses, what it downloads, and exactly what that conversion keeps or drops.
| Category | Archives |
|---|---|
| File extension | .cpio |
| FileFlip support | Read only, so it is a source rather than a target |
| Conversions available | 11 |
| Engines | libarchive |
| Downloaded to your browser | 1.0 MB on the first conversion, then cached |
What is a CPIO file?#
A CPIO file is a Unix archive produced by the cpio utility, storing a sequence of files with their Unix permissions and ownership one after another with no compression of its own.
Use cpio when building or inspecting an initramfs image or an RPM payload, since both specifically expect a cpio archive rather than tar.
Convert a CPIO archive to tar when the files need to go somewhere that expects the more common format, since tar is understood by nearly every archive tool.
The CPIO file format reference covers the specification, the programs that open one, and what each conversion keeps or drops.
CPIO questions people ask#
What is a CPIO file used for today?
A CPIO file is a Unix archive most commonly found in two places today: the initramfs image the Linux kernel unpacks early in boot, and the payload of an RPM package. Outside those two roles it has mostly been replaced by tar.
Why does an initramfs use cpio instead of tar?
Linux's kernel unpacks the initramfs cpio archive itself before any userspace tools are available, and cpio's simpler, more compact header format was easier to support directly in the kernel than tar's. The specific variant used is called newc, an ASCII-header cpio format.
How do I get the files out of an RPM package's cpio payload?
An RPM file's payload is a compressed cpio archive sitting after the package's header, and the standard way to reach it is to pipe rpm2cpio through cpio -idmv, which extracts the files without installing the package.