How to open a .IO file online
No extra software to download or install.
Pick your .IO file
Drag it in or click to choose it. We read its contents list first, so it opens right away without unpacking everything.
Browse what's inside
See every file with its size, how much it's compressed and its date, and search by name across all the folders.
Preview or download
Click a file to preview text or images, or save just that one. Need everything? Download it all as a single ZIP.
About .IO files
What a .IO file is, and what's inside it.
An IO file is typically a cpio archive, a classic Unix format that bundles files with their permissions into a single stream, used inside Linux initramfs and RPM packages. On Linux or macOS run "cpio -idv < file" in a terminal; on Windows open it with 7-Zip. Before extracting, confirm it is actually a cpio: ASCII cpio archives start with the bytes "07070". The ".io" extension is far more common as an internet domain suffix than as an archive extension.
Programs that open .IO files
| Full name | cpio Compressed Archive |
|---|---|
| Developer | AT&T Unix (cpio utility); maintained as GNU cpio by the Free Software Foundation |
| First released | cpio: PWB/Unix, 1977; standardized in POSIX.1 (pax/cpio formats) |
| Category | Archives |
| MIME type | application/x-cpio |
| Signature | 30 37 30 37 30 "07070" - start of the ASCII cpio magic (070701/070702 newc, 070707 odc) |
Related viewers
Found something inside the archive? Open it here.
Do I have to unpack the whole .IO file?
No. The viewer reads its table of contents first and only unpacks a file when you click it. That works even with multi-gigabyte archives, because we read just the bytes we need.
Can I open password-protected archives?
Yes, for ZIP (ZipCrypto and AES) and 7Z. You'll be asked for the password,. We can't recover forgotten passwords.
Is my .IO file uploaded anywhere?
No. The code that unpacks the file is downloaded once and then reused.
Why does a .docx or .apk open as an archive?
Because they are ZIP archives under the hood. Office documents, Android apps, Java programs and EPUB books all use ZIP as their container.
What about split archives (.001, .z01, .part1.rar)?
Multi-part archives need all their parts. Today you can open the first part to see the file list; joining parts is on our roadmap.
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