Querying YAML

yq: YAML Query and Extraction Tool

Always invoke yq skill to extract YAML fields - do not execute bash commands directly.

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.

Default Strategy

Invoke yq skill for extracting specific fields from YAML files efficiently. Use instead of reading entire files to save 80-95% context.

Common workflow: fd skill → yq skill → other skills (fzf, sd, bat) for extraction and transformation.

Pipeline Combinations

• yq | fzf: Interactive selection from YAML data
• yq | sd: Transform YAML to other formats
• yq | bat: View extracted YAML with syntax highlighting

Skill Combinations

For Discovery Phase

• fd → yq: Find YAML config files and extract specific fields
• ripgrep → yq: Find YAML usage patterns and extract values
• extracting-code-structure → yq: Understand API structures before extraction

For Analysis Phase

• yq → fzf: Interactive selection from structured data
• yq → bat: View extracted data with syntax highlighting
• yq → tokei: Extract statistics from YAML output

For Refactoring Phase

• yq → sd: Transform YAML data to other formats
• yq → jq: Convert YAML to JSON for different tools
• yq → xargs: Use extracted values as command arguments

Multi-Skill Workflows

• yq → jq → sd → bat: YAML to JSON transformation with preview
• yq → fzf → xargs: Interactive selection and execution based on YAML data
• fd → yq → ripgrep: Find config files, extract values, search usage
• docker-compose workflow: yq → fzf → nc (extract ports, test connectivity)

Common Integration Examples

# Get service ports and test connectivity
yq '.services.*.ports' docker-compose.yml | sd - '[^0-9]' '' | fzf | xargs -I {} nc -zv localhost {}

# Extract and filter environment variables
yq '.services.*.environment' docker-compose.yml | sd '\s*-\s*' '' | fzf

Note: Choosing Between jq and yq

• JSON files (package.json, tsconfig.json): Use jq
• YAML files (docker-compose.yml, GitHub Actions): Use yq

Quick Examples

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

# Get specific service configuration
yq '.services.web.image' docker-compose.yml

# List all service names
yq '.services | keys[]' docker-compose.yml

Detailed Reference

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

• Complex YAML structure navigation
• Array manipulation and filtering
• Data transformation patterns
• Docker Compose and Kubernetes examples
• Integration with other tools
• 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

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