yq: YAML Query and Extraction Tool

Use yq to extract specific fields from YAML files without reading entire file contents, saving 80-95% context usage.

When to Use yq

Use yq when:

• Need specific field(s) from structured YAML file
• File is large (>50 lines) and only need subset of data
• Querying nested structures in YAML
• Filtering/transforming YAML data
• Working with docker-compose.yml, GitHub Actions workflows, K8s configs

Just use Read when:

• File is small (<50 lines)
• Need to understand overall structure
• Making edits (need full context anyway)

Tool Selection

JSON files → Use jq

• Common: package.json, tsconfig.json, lock files, API responses

YAML files → Use yq

• Common: docker-compose.yml, GitHub Actions, CI/CD configs

Both tools extract exactly what you need in one command - massive context savings.

Quick Examples

# Get version from package.json
jq -r .version package.json

# Get service ports from docker-compose
yq '.services.*.ports' docker-compose.yml

Detailed Reference

For comprehensive yq patterns, syntax, and examples, load yq guide:

• Core patterns (80% of use cases)
• Real-world workflows (Docker Compose, GitHub Actions, Kubernetes)
• Advanced patterns and edge case handling
• Output formats and pipe composition
• Best practices and integration with other tools