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Overview JQ Expressions

1. Introduction to JQ​

JQ is a powerful command-line JSON processor used to parse, filter, and transform JSON data. It allows users to extract specific information, format data, and apply functions without writing complex scripts.

Why Use JQ?​

Extract specific data from large JSON responses
Filter and manipulate JSON efficiently
Transform JSON structure for better readability
Supports conditionals, loops, and advanced expressions

Basic JQ Syntax​

  • Extract fields: .field
  • Filter arrays: .array[]
  • Modify values: .field |= value
  • Use pipes (|) to chain operations
  • Apply functions: map, select, contains, etc.

2. Using JQ to Extract Data​

JQ expressions can be used to filter JSON responses by extracting specific values.

Example JSON Input​

{
  "results": [
    {
      "max_injection_score": 0.85,
      "max_jailbreak_score": 0.92,
      "chunk_results": [
        {
          "BENIGN": 0.05,
          "INJECTION": 0.85,
          "JAILBREAK": 0.92,
          "start": 0,
          "end": 52
        }
      ]
    }
  ]
}

Example: Extracting a Single Field​

Extract max_injection_score from the JSON:

jq '.results[0].max_injection_score' response.json

Output:

0.85

3. Filtering JSON Data​

JQ allows filtering specific parts of a JSON object.

Example: Extract INJECTION and JAILBREAK Scores​

jq '.results[0].chunk_results[0] | {INJECTION, JAILBREAK}' response.json

Output:

{
  "INJECTION": 0.85,
  "JAILBREAK": 0.92
}

Example: Extract Only High-Risk Cases​

Get responses where INJECTION > 0.8:

jq '.results[0].chunk_results[] | select(.INJECTION > 0.8)' response.json

Output:

{
  "BENIGN": 0.05,
  "INJECTION": 0.85,
  "JAILBREAK": 0.92,
  "start": 0,
  "end": 52
}

4. Working with JSON Arrays​

JQ provides array functions to process multiple items.

Example: Extracting Values from an Array​

jq '.results[].chunk_results[].INJECTION' response.json

Output:

0.85

Example: Listing All Scores​

jq '.results[].chunk_results[] | {BENIGN, INJECTION, JAILBREAK}' response.json

Output:

{
  "BENIGN": 0.05,
  "INJECTION": 0.85,
  "JAILBREAK": 0.92
}

5. Using Conditionals in JQ​

JQ supports if-else statements to modify JSON based on conditions.

Example: Marking High-Risk Entries​

jq '.results[].chunk_results[] | if .JAILBREAK > 0.8 then "High Risk" else "Low Risk" end' response.json

Output:

"High Risk"

6. Transforming JSON Structure​

JQ can restructure JSON to match specific output needs.

Example: Flattening JSON Output​

Convert nested JSON into a simpler structure:

jq '.results[].chunk_results[] | {Risk_Score: .JAILBREAK, Position: {start, end}}' response.json

Output:

{
  "Risk_Score": 0.92,
  "Position": {
    "start": 0,
    "end": 52
  }
}

7. Working with JSON Objects​

JQ allows modifying existing values in JSON.

Example: Rounding Values​

jq '.results[].chunk_results[] | {JAILBREAK: (.JAILBREAK | round)}' response.json

Output:

{
  "JAILBREAK": 1
}

8. Combining JQ Expressions​

Multiple JQ operations can be chained using pipes (|).

Example: Extract and Transform Data​

jq '.results[].chunk_results[] | {JAILBREAK: .JAILBREAK, Status: (if .JAILBREAK > 0.8 then "Danger" else "Safe" end)}' response.json

Output:

{
  "JAILBREAK": 0.92,
  "Status": "Danger"
}

9. Using JQ in YAML Configurations​

JQ expressions are commonly used in YAML for JSON transformations.

Example: JQ in a YAML-Based API Configuration​

transform_response: |
  {
    "max_injection_score": json["results"][0]["max_injection_score"],
    "max_jailbreak_score": json["results"][0]["max_jailbreak_score"],
    "chunk_results": json["results"][0]["chunk_results"] | map({INJECTION, JAILBREAK})
  }

This extracts:

  • The max injection and jailbreak scores.
  • A transformed list of INJECTION and JAILBREAK scores.