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piawka is a simple command-line tool to calculate within- and between-population nucleotide diversity statistics using discrete variant calls from the VCF files. Largely inspired by pixy, piawka builds upon it in a few aspects:

The name of the tool is pronounced pi: jaf ka: after a Russian word meaning "leech".

• supports arbitrary ploidy level in the VCF files
• can use multiallelic SNPs, in biallelic mode also uses multiallelic SNPs that have two alleles in the analyzed groups
• handles missing data in a sensible way

Other features are

• small weight and portablility, runs wherever vanilla AWK can run (Windows, macOS, Linux...) and requires no installation
• fast (and can be parallelized with GNU parallel -- see Usage)
• includes additional useful stuff : Fst, Tajima's D-like statistic (with missing data correction), Ronfort's rho (useful for inter-ploidy divergence comparisons)

piawka is written in the (very underappreciated) language of awk. It is fast and user-friendly at processing text tables, ensuring freedom of many dependencies and compilation issues. Recent advancements of GNU awk implementation, gawk, allow going beyond one-liner programs due to modularity and interface for writing C extensions.

• Available statistics
• Installation
• Usage
• Examples
• Pro tips
• Known issues
• References
• Alternatives