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[GUIDE] Walkthrough for `b2nd-to-zarr` CLI tool

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
80/100
Issue type
Documentation
Clarity
Clearly specified
Activity status
Active
Tech stack
python
Domain
cli, documentation

Research direction

The guide will be created at doc/guides/b2nd_to_zarr.md. Start by examining the existing guide doc/guides/parquet_to_blosc2.rst for structure and style. Review the b2nd-to-zarr CLI tool's help output and source code to understand its options. Write the guide with the specified sections, including runnable shell and Python snippets. Finally, add the new guide to doc/guides/index.rst under the 'Command line tools' section.

Written by the indexing model from the issue text.

Description

documentation sustain-2026

b2nd_to_zarr is a robust CLI tool supporting Zarr v2 and v3, sharding (--sharded, --shards), custom chunk/codec mapping, memory buffer control (--buffer-size), and data integrity verification (--verify, --full-verify).

While parquet-to-blosc2 has a dedicated walkthrough guide in doc/guides/parquet_to_blosc2.rst, b2nd-to-zarr currently has no guide in doc/guides/ and is only mentioned in a single line within the installation docs.

Suggested Work

Create a new Markdown guide at doc/guides/b2nd_to_zarr.md (and add it to doc/guides/index.rst under Command line tools).

Cover the following steps with runnable shell and Python snippets:

  1. Prerequisites & Installation: Installing the [zarr] optional extra (pip install "blosc2[zarr]").
  2. Step 1 — Create a sample .b2nd array: A small Python snippet to generate a sample multidimensional array.
  3. Step 2 — Basic export to Zarr v3: Converting the file using b2nd-to-zarr sample.b2nd sample.zarr.
  4. Step 3 — Custom chunk layout & memory buffer: Overriding chunk shapes (--chunks) and controlling memory footprint with --buffer-size.
  5. Step 4 — Zarr v3 Sharding: Using --sharded to map Blosc2 chunks to Zarr shards and Blosc2 blocks to inner Zarr chunks.
  6. Step 5 — Codec and filter selection: Explicitly specifying codecs (--codec zstd, --clevel 5, --shuffle bitshuffle).
  7. Step 6 — Integrity verification: Checking data consistency with --verify and --full-verify.
  8. Cross-link with doc/guides/parquet_to_blosc2.rst and the Zarr source reference docs.
Dominant language
Python
Stars
211
Forks
63
Avg merge
2d 1h
Merged PRs (30d)
9

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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