.BZ2 file signature
A bzip2 compressed data file begins with the bytes 42 5A 68 (BZh in ASCII) at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless BZIP file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 42 5A 68Followed by the block size digit 1 to 9, e.g. BZh9. | BZh |
MIME type: application/x-bzip2 · usual extensions: .bz2
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.bz2
file file.bz2Windows (PowerShell):
Format-Hex -Path file.bz2 -Count 32If the bytes do not match
A file named .bz2 whose first bytes are something else is not a BZIP file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the BZIP guide explains what a genuine file should contain.