Format Definition Files

BetterZip 6 can make use of external command-line tools through custom format definitions. This page collects ready-made definitions for tools that don’t ship with BetterZip. Each row links to the JSON file and to the tool’s home page, where you get the tool itself.

How to use a definition

Install the tool. The quickest way is Homebrew, e.g. brew install lzip plzip.
Download the JSON file and open it in a text editor.
Check installPath. Homebrew installs tools to /opt/homebrew/bin on Apple silicon Macs and to /usr/local/bin on Intel Macs; MacPorts uses /opt/local/bin on both. The files ship with the Apple silicon path, so change it if you’re on an Intel Mac or use MacPorts. Running which lzip in Terminal tells you the path.
Open BetterZip > Settings > Helpers, click +, paste the JSON into the editor sheet, and save.

Each file uses a tag between 1001 and 1004. If you already have a custom definition with the same tag, pick another number of 1000 or higher.

Definitions

Tool	Last update	Tool version	Format file	Tool
lzip LZMA-based compressor with a simple, well-documented file format designed for long-term archiving. Handles `.tar.lz` and `.tlz`. The definition decompresses with `lzip` and compresses with `plzip`, the multithreaded variant, so install both.	2026-09-14	lzip 1.26 plzip 1.13	lzip.json	nongnu.org/lzip
lz4 Very fast compressor and decompressor, trading ratio for speed. Handles `.tar.lz4` and `.tl4`. The compression levels map to lz4’s `-1`, `-4`, `-8`, and `-12` and use the thread count from Settings > Advanced.	2026-09-14	1.10.0	lz4.json	github.com/lz4/lz4
lrzip Long-range compressor for large files with lots of redundancy, such as disk images or VM snapshots. Handles `.tar.lrz` and `.tlrz`. Fast uses the LZO backend, Normal and High LZMA, and Best ZPAQ, which is very slow but gives the smallest files. Streaming through a pipe limits lrzip’s compression window, so files compressed from BetterZip come out a bit larger than from the command line.	2026-09-14	0.7.2	lrzip.json	github.com/ckolivas/lrzip
dar Disk ARchive, a backup-oriented archiver with its own format, slicing, and encryption. Handles `.dar`. This is a `user`-class definition: listing, extraction, creation, testing, and splitting are all driven by dar’s own options. Compression levels use gzip, zstd, and xz; the encryption method maps to `-K aes:`. Preliminary – if something doesn’t work with your dar build, tell me.	2026-09-14	2.8.6	dar.json	dar.linux.free.fr

Contributing a definition

If you have written a definition for another tool, send it to me: . Working definitions get added here with your credit if you want it. The format specification describes every field.