nail

name	nail
description	Use this skill when the user wants to analyze, describe, convert, filter, transform, or inspect Parquet, CSV, or XLSX datasets from the command line.

nail Plugin

Lightning-fast data analysis CLI for Parquet, CSV, and XLSX files. Describe, filter, transform, join, compare, and analyze datasets with rich statistics and schema introspection.

Commands

Data Analysis

• nail data describe — Show global file overview and metadata
• nail data stats — Calculate descriptive statistics
• nail data head — Display first N rows
• nail data schema — Display schema information
• nail data convert — Convert between file formats

Utility

• nail self version — Print nail version
• nail _ _ — Passthrough to nail CLI

Usage Examples

• "Describe this Parquet file"
• "Show the first 20 rows of the dataset"
• "Calculate statistics for the price and volume columns"
• "Convert this CSV to Parquet"
• "Show the schema of the data file"

Installation

cargo install nail-parquet

Examples

# Describe a dataset
nail data describe sales.parquet

# Statistics for specific columns
nail data stats sales.parquet -c "revenue,profit" --percentiles "0.5,0.9,0.99"

# Correlation matrix
nail _ _ correlations sales.parquet -c "price,volume,discount" --tests t_test

# Frequency distribution
nail _ _ frequency sales.parquet -c "category,region"

# First 20 rows
nail data head sales.parquet -n 20

# Display schema
nail data schema sales.parquet

# Convert CSV to Parquet
nail data convert data.csv -o data.parquet

# Convert Parquet to JSON
nail data convert data.parquet -o data.json -f json

# Remove duplicates
nail _ _ dedup raw.parquet --row-wise -c "id" -o unique.parquet

# Detect and remove outliers
nail _ _ outliers unique.parquet -c "price" --method iqr --remove -o cleaned.parquet

# Create a new column
nail _ _ create cleaned.parquet --column "margin=(price-cost)/price" -o enriched.parquet

# Bin continuous variables
nail _ _ binning opt.parquet -c "age" -b "18,25,35,50,65" --method custom --labels "18-24,25-34,35-49,50-64,65+" -o binned.parquet

# Pivot table
nail _ _ pivot binned.parquet -i "age_binned" -c "category" -l "revenue" --agg sum -o summary.parquet

# Compare two datasets
nail _ _ diff yesterday.parquet --compare today.parquet --keys "id" --changes-only

Key Features

• Multi-format support: Parquet, CSV, XLSX, JSON, and text output
• Rich statistics: Descriptive stats, correlations, frequency distributions, outliers
• Data transformation: dedup, filter, binning, pivot, merge, split, sort, shuffle
• Schema introspection: Display column types, metadata, and schema details
• Format conversion: Convert between Parquet, CSV, XLSX, JSON, and text
• Column operations: Create, rename, drop, select, fill missing values
• Row operations: head, tail, sample, preview, filter, deduplicate
• Join datasets: merge two datasets on common keys
• Compare datasets: diff with key-based change detection
• Performance: Multi-threaded with -j jobs flag
• Output control: -o for output file, -f for format override

Notes

• Use nail <command> --help for full usage details of any subcommand
• The -f flag overrides output format: json, csv, parquet, or text
• The -j flag controls parallelism (useful for large datasets)
• Many commands support -o to write results to a file instead of stdout
• nail auto-detects input format from file extension