yq YAML Processor

yq is a portable command-line YAML, JSON, XML, CSV, and properties processor that uses syntax similar to jq (the popular JSON processor). Created by Mike Farah in 2017 and rewritten in Go (replacing the original Python implementation), yq has over 13,000 stars as of 2026 and has become the standard tool for processing YAML files in DevOps, CI/CD pipelines, and Kubernetes configurations. Key features include: jq-like syntax (using the same intuitive expression language as jq for navigating, filtering, and transforming data structures), multi-format support (reading and writing YAML, JSON, XML, CSV, and properties files with automatic format conversion), deep traversal (navigating nested data structures with dot notation and bracket notation, supporting wildcards, array indices, and recursive descent), in-place modification (modifying YAML files while preserving comments, formatting, and document structure), multi-document support (processing YAML files with multiple documents separated by dashes, with operations applied to each document independently), string interpolation (embedding expressions within strings for dynamic value construction), comparison and sorting (comparing values, sorting arrays, and selecting unique elements), mathematical operations (basic arithmetic on numeric values), variable assignment (storing intermediate results in variables for complex operations), shell integration (reading from stdin and writing to stdout for piping between commands), GitHub Actions integration (a pre-built action for modifying YAML files in CI/CD workflows), and evaluation modes (eval for expressions, and the newer write/ea commands for bulk modifications).