Changelog

All notable changes to jlkit are documented here. The format follows Keep a Changelog; this project adheres to Semantic Versioning.

0.1.1 — 2026-08-28

First release published to PyPI.

head / tail accept -n/--lines N (GNU-style) in addition to the positional count.

jlkit head data.jsonl (count omitted) no longer errors with "invalid int value" — a lone positional is treated as the file, not the count.
jlkit head <non-number> file now exits 2 with a clear message instead of an argparse type error.

Initial public release (GitHub tag only; superseded by 0.1.1 on PyPI).

head N / tail N — first/last N records, streaming; tail keeps only an N-record ring buffer.
select FIELDS — project comma-separated dotted paths (id,user.name,ts).
filter EXPR — keep records matching a safe no-eval predicate grammar: ==,!=,<,<=,>,>=, exists, contains, and/or/not, parentheses, dotted paths.
stats — per-field presence %, null %, observed types, numeric min/max/mean/stddev, string cardinality; nested keys flattened to dotted paths.
schema — infer a JSON Schema (draft 2020-12, structural subset) over a full pass.
validate — report malformed lines by 1-indexed number; with --schema, also report non-conforming records. Exits non-zero on any failure (CI-friendly).
Global --limit N — stop after N input records.
Transparent .gz input; reads a file arg or stdin.
Requires Python 3.12+ (argparse in 3.12 handles options interspersed with positional arguments, e.g. jlkit select name --limit 1 data.jsonl).

A missing or unreadable input file now prints a one-line jlkit CMD: cannot open '...': <reason> (exit 2) instead of a traceback.
Writing to a closed pipe (jlkit ... | head) exits quietly instead of raising BrokenPipeError on shutdown.