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jq JSON essentials

Select, reshape, filter and summarize JSON with small shell-friendly examples.

24 entries

Inspect and select

Pretty-print JSON: jq '.' data.json
Parses input and formats each JSON value. [2]
Select a property: jq '.name' data.json
Missing object keys generally produce null. [2]
Nested property: jq '.user.name' data.json
Input structure must support the path. [2]
First array element: jq '.[0]' data.json
Indexes are zero-based. [2]
Last array element: jq '.[-1]' data.json
Negative index counts backward. [2]
Iterate array values: jq '.[]' data.json
Emits each element as a separate result. [2]
Array slice: jq '.[1:4]' data.json
The end index is excluded. [2]
Raw string output: jq -r '.name' data.json
Removes JSON string quoting, not arbitrary escaping for a shell. [2]

Project two fields: jq '{name, count}' data.json
Creates a new object using these keys. [1]
Rename a field: jq '{label: .name}' data.json
Constructs a differently named output property. [1]
Keep matching objects: jq '.[] | select(.active == true)' data.json
select emits only values satisfying the test. [1]
Map an array: jq 'map(.name)' data.json
Returns an array of each element's name. [1]
Count elements: jq 'length' data.json
Meaning depends on the input type. [1]
List object keys: jq 'keys' data.json
Sorts object keys. [1]
Sorted objects: jq 'sort_by(.name)' data.json
Expects an array. [1]
Deduplicate values: jq 'unique' data.json
Sorts and removes duplicate array values. [1]

Fallback value: jq '.name // "unknown"' data.json
// also uses the fallback for false, not only null. [1]
Check key presence: jq 'has("name")' data.json
Distinguishes missing keys from an explicit null value. [1]
Pass a string safely: jq --arg wanted 'Atlas' '.[] | select(.name == $wanted)' data.json
--arg avoids injecting shell text into filter syntax. [1]
Pass a JSON value: jq --argjson limit 3 '.[:$limit]' data.json
--argjson parses its argument as JSON. [1]
Compact output: jq -c '.' data.json
Emits compact JSON values. [1]
Slurp a stream: jq -s '.' data.json
Reads input values into one array; memory use grows with input. [1]
Create JSON without input: jq -n --arg name 'Atlas' '{name: $name}'
Avoids string-concatenating a JSON document. [1]
Fail on false/null result: jq -e '.active == true' data.json
Exit status depends on the last result; handle empty output too. [1]

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Updated 2026-10-19jq · core filters / POSIX shell quoting

cheatsheetatlas.com/sheets/jq/ · Updated 2026-10-19 · jq · core filters / POSIX shell quoting