jq

Querying and transforming JSON in the terminal: fields, arrays, filters, output formats.

Basics

Pretty-print JSON

jq . <file>.json

Get a field

jq '.name' <file>.json

Nested field without quotes in output

jq -r '.user.email' <file>.json

Keys of an object

jq 'keys' <file>.json

Compact one-line output

jq -c . <file>.json

Field of every element

jq -r '.[].name' <file>.json

Array length

jq 'length' <file>.json

First element

jq '.[0]' <file>.json

Filter elements by a condition

jq '.[] | select(.status == "active")' <file>.json

Build new objects from elements

jq '[.[] | {id, name: .user.name}]' <file>.json

Sort by a field

jq 'sort_by(.createdAt) | reverse' <file>.json

Count by a fieldadvanced

jq 'group_by(.status) | map({status: .[0].status, count: length})' <file>.json

Export to CSVadvanced

jq -r '.[] | [.id, .name, .email] | @csv' <file>.json

Change a field and saveadvanced

jq '.version = "1.2.3"' package.json > tmp.json && mv tmp.json package.json

Pass a shell variable into jqadvanced

jq --arg name "$NAME" '.[] | select(.name == $name)' <file>.json

Find a key anywhere in the documentadvanced

jq '.. | .<json_key>? // empty' <file>.json

Parse JSON logs line by lineadvanced

tail -f app.log | jq -R 'fromjson? | select(.level == "error")'