CPIO to TAR Converter
FileFlip converts CPIO to TAR entirely inside your browser, using libarchive compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a CPIO file to TAR?#
- Drop your CPIO file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to TAR and the conversion starts on its own. FileFlip downloads 1.0 MB of WebAssembly the first time and nothing after that, then runs libarchive on your own machine.
- Save the TAR file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting CPIO to TAR lose quality?#
No. Converting CPIO to TAR does not touch the files inside the archive. Each member is read out and written back byte for byte, so only the wrapper around them changes and nothing is recompressed.
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 CPIO to TAR actually does to the file#
Converting CPIO to TAR runs on libarchive, downloads 1.0 MB of WebAssembly the first time and nothing after that, copies the archived files through unchanged, keeps file contents, and drops file timestamps and file permissions.
| Engine | libarchive |
|---|---|
| Conversion path | 2 steps: CPIO → the unpacked files → TAR |
| Downloaded to your browser | 1.0 MB, once, then cached by your browser |
| Quality | Lossless, contents copied unchanged |
| You get back | One file |
| Where it runs | On the page's own thread, so a very large file will make the tab wait |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| File contents | Kept | Carried through into the converted file. |
| File timestamps | Dropped | The target format has nowhere to put it. |
| File permissions | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- the built-in ZIP and TAR writer records no timestamps, permissions, or ownership
- every entry is extracted into memory before anything is written, so a very large archive can exhaust it
- this conversion runs on the page's own thread, so a large file will freeze the tab while it works
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.
What is a TAR file?#
A TAR file concatenates files, directories and 512-byte headers recording each item's owner, permissions and modification time into one stream, a format Unix introduced in 1979 for writing straight to magnetic tape with no compression involved.
Use TAR when file ownership, permissions and symlinks have to survive the trip, which matters for backups and Unix software distribution and doesn't matter for a folder of photos.
Convert an uncompressed TAR to a compressed variant like TGZ or TXZ when the archive is being stored or transferred and its size actually matters.
CPIO to TAR 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.
Why does TAR need a compressor like gzip?
TAR only concatenates files and their metadata into one stream; it was designed in 1979 to write straight to magnetic tape and never included compression at all. That's why a tarball is normally paired with gzip, bzip2 or xz, producing .tar.gz, .tar.bz2 or .tar.xz.