Skill v1.0.0
currentAutomated scan100/100version: "1.0.0" name: jq description: Use when the user needs to query, filter, reshape, extract, create, or construct JSON data — including API responses, config files, log output, or any structured data — or when helping the user write or debug JSON transformations.
jq — Built-in JSON Processor
Crush ships a built-in jq command (via github.com/itchyny/gojq) available in the bash tool. No external binary is required.
Supported Flags
| Flag | Description | |
|---|---|---|
-r, --raw-output | Output strings without quotes | |
-j, --join-output | Like -r but no trailing newline | |
-c, --compact-output | One-line JSON output | |
-s, --slurp | Read all inputs into an array | |
-n, --null-input | Use null as input (ignore stdin) | |
-e, --exit-status | Exit 1 if last output is false or null | |
-R, --raw-input | Read each line as a string, not JSON | |
--arg name value | Bind $name to a string value | |
--argjson name value | Bind $name to a parsed JSON value |
File arguments after the filter are also supported: jq '.foo' file.json.
Differences from Standard jq
The built-in uses gojq, which is a pure-Go jq implementation. Key differences:
- No object key ordering — keys are sorted by default;
keys_unsorted
and -S are unavailable.
- Arbitrary-precision integers — large integers keep full precision
(addition, subtraction, multiplication, modulo, division when divisible).
- String indexing —
"abcde"[2]returns"c". - Not supported —
--ascii-output,--seq,--stream,
--stream-errors, -f/--from-file, --slurpfile, --rawfile, --args, --jsonargs, input_line_number, $__loc__, some regex features (backreferences, look-around).
- YAML — gojq supports
--yaml-input/--yaml-outputbut the
built-in does not currently expose these flags.
Common Patterns
Extract a field:
echo '{"name":"crush"}' | jq '.name'
Filter an array:
echo '[1,2,3,4,5]' | jq '[.[] | select(. > 3)]'
Reshape objects:
echo '{"first":"Ada","last":"Lovelace"}' | jq '{full: (.first + " " + .last)}'
Use variables:
echo '{}' | jq --arg host localhost --argjson port 8080 '{host: $host, port: $port}'
Slurp multiple JSON values:
echo '{"a":1}{"b":2}' | jq -s '.'
Compact output for piping:
echo '{"a":1}' | jq -c '.a += 1'
Raw string output:
echo '["one","two","three"]' | jq -r '.[]'
Process a file:
jq '.dependencies | keys' package.json
Null input for constructing JSON:
jq -n --arg msg hello '{"message": $msg}'
Tips
- Pipe jq output to other commands:
jq -r '.url' data.json | xargs curl - Chain filters with
|inside the expression, not shell pipes. - Use
tryto suppress errors on missing keys:jq 'try .foo.bar' - Use
// "default"for fallback values:jq '.name // "unknown"' - Use
@csv,@tsv,@base64,@html,@urifor format strings.