avz

A blistering-fast Avro CLI tool — a modern replacement for Java's avro-tools and Python's fastavro.

Supports local files, glob patterns, and S3 URIs.

Install

cargo install avz

Or build from source:

git clone https://github.com/arunma/avz.git
cd avz
cargo build --release
# binary at target/release/avz

Quick Start

# peek at the first 5 records
avz head -n 5 data.avro

# pretty-print with syntax highlighting
avz cat --pretty data.avro

# search for a record by regex
avz grep "user_id.*12345" data.avro

# search for a literal string (no regex)
avz grep -F "300376641*2967" data.avro

# count records across files using a glob
avz count "logs/*.avro"

# works with S3 too
avz cat "s3://my-bucket/events/dt=2026-03-16/*.avro" --pretty

Note: Quote glob patterns and S3 URIs to prevent your shell from expanding them.

Commands

Command	Description
`cat`	Print all records as JSON (`--pretty` for color output)
`head`	Print the first N records (default 10)
`schema`	Print the Avro schema (colorized)
`count`	Count records in one or more files
`meta`	Print file metadata (codec, sync marker, user metadata)
`grep`	Search records by regex or literal string (`-F`)
`fromjson`	Convert newline-delimited JSON to an Avro file
`concat`	Concatenate multiple Avro files into one
`recodec`	Re-encode with a different codec
`fingerprint`	Print schema fingerprint (CRC-64-AVRO, MD5, SHA-256)
`validate`	Validate file integrity or check schema compatibility
`random`	Generate random records from a schema

Usage

Reading files

# single file
avz cat data.avro

# glob pattern
avz count "events/*.avro"

# multiple files
avz concat a.avro b.avro c.avro --output merged.avro

# S3 URI (uses default AWS credentials)
avz schema "s3://bucket/prefix/file.avro"

# S3 glob
avz count "s3://bucket/events/dt=2026-03-16/*.avro"

Grep

Search through records and print the entire matching record as JSON:

# regex search
avz grep "error.*timeout" events.avro

# literal string (-F), useful when pattern has special chars
avz grep -F "amount=100.00" transactions.avro

# case-insensitive
avz grep -i "failed" events.avro

# invert match (show non-matching records)
avz grep -v "SUCCESS" events.avro

# count matches only
avz grep -c "PARTY" events.avro

# pretty-print matches
avz grep --pretty "entity_id" events.avro

Writing and converting

# JSON to Avro
avz fromjson --schema schema.json --output data.avro input.json

# from stdin
cat records.jsonl | avz fromjson --schema schema.json --output data.avro

# with compression
avz fromjson --schema schema.json --output data.avro --codec snappy input.json

# re-encode existing file with a different codec
avz recodec data.avro --codec zstandard --output data-zstd.avro

Inspection

# schema
avz schema data.avro

# metadata (codec, sync marker)
avz meta data.avro

# schema fingerprints
avz fingerprint data.avro
avz fingerprint --algorithm sha256 data.avro

# validate file integrity
avz validate data.avro

# check schema compatibility
avz validate data.avro --reader-schema new_schema.json

Generate test data

# random JSON records from a schema
avz random --schema schema.json -n 100

# reproducible output with a seed
avz random --schema schema.json -n 10 --seed 42 --pretty

# write directly to Avro
avz random --schema schema.json -n 1000 --format avro --output test.avro

Supported Codecs

null, deflate, snappy, zstandard, bzip2, xz

License

MIT OR Apache-2.0

avz 0.1.0

avz