Open BZ2 files on Mac
Use bzip2 in Terminal to decompress a .bz2 on Mac, or open it in Kernir and extract the entry. A standalone BZ2 normally holds one compressed file. Kernir reads BZ2, while TAR.BZ2 is a separate archive combination that it can also write.
Identify the expected result
An exported notes.txt.bz2 should normally become notes.txt. A Source.tar.bz2 first represents a TAR compressed with bzip2, so its useful contents may be many files and folders. For that second case, tar can read both layers directly; follow the TAR.BZ2 guide instead.
Decompression restores the original bytes, not a new document format. A database dump remains a database dump, even if it is much larger than the compressed download. You may need a separate application to inspect or import it after extraction.
Keep the compressed original
Open Terminal and go to the file's directory. For a file in Downloads:
cd ~/Downloads
bzip2 -dk "notes.txt.bz2"
Replace the example filename. The -d option decompresses, and -k keeps the input. The expected output here is notes.txt beside the original archive. The bzip2 manual documents these options and the normal output naming.
Choose a location where the output does not already exist. If the tool refuses to replace an existing file, move your work aside or use a fresh folder rather than adding a force option automatically. Running plain decompression without the keep option can remove the compressed input after success.
Before a large extraction, consider the space needed for both copies. The compressed download size is not the same as the size of the expanded file.
Test before using the result
bzip2 -t "notes.txt.bz2"
This reads and tests the compressed data without creating a new document. If it reports an error, check whether the download finished and compare with the publisher's checksum if one is supplied. An incomplete or corrupt file may leave a partial output after an extraction attempt.
If testing succeeds but the extracted file will not open, check the document type and the application you are using. An archive tool does not interpret a database format, execute a program or repair a damaged file inside the compressed stream.
Browse and extract in Kernir
The Mac download is coming soon. You can view the source and build instructions on GitHub. These steps describe the current app workflow.
Choose File › Open… (⌘O), select the BZ2, then select the entry shown in the archive window. Use File › Extract… (⌘E) and choose a destination. The current standalone-stream reader names the entry from the input filename without .bz2; a missing original extension may need clarification from the sender.
Standalone BZ2 is read-only in Kernir. To package the extracted document again in the app, create a ZIP or another writable format. Saving as ZIP changes the container; it does not produce another BZ2. If your input contains a TAR tree, Kernir treats the supported TAR.BZ2 combination as a writable archive.
To try a small file with known contents, use the sample archive library. Substitute the downloaded sample's filename in the commands above.
Kernir.dmg, signed and notarized. Requires macOS 14 or later.
Related guides
App steps were checked against Kernir source code. Command examples were checked with test archives on Linux using libarchive and the named utilities, not in a new macOS session. Updated .
