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.

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-output but the built-in does not currently expose these flags.

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}'