It's a tool that's used for performing queries on streams of records in various formats.

The goal is to make ad-hoc exploration of data sets easy without having to use more heavy-weight tools like SQL/MapReduce/custom programs. rq fills a similar niche as tools like awk or sed, but works with structured (record) data instead of text.

It was created with love out of the best parts of Rust, C and Javascript, and is distributed as a dependency-free binary on many operating systems and architectures.