tldr/pages/common/jq.md

jq

A command-line JSON processor that uses a domain-specific language. More information: https://stedolan.github.io/jq.

• Output a JSON file, in pretty-print format:

jq . {{file.json}}

• Output all elements from arrays (or all key-value pairs from objects) in a JSON file:

jq '.[]' {{file.json}}

• Read JSON objects from a file into an array, and output it (inverse of jq .[]):

jq --slurp . {{file.json}}

• Output the first element in a JSON file:

jq '.[0]' {{file.json}}

• Output the value of a given key of the first element in a JSON text from stdin:

cat {{file.json}} | jq '.[0].{{key_name}}'

• Output the value of a given key of each element in a JSON text from stdin:

cat {{file.json}} | jq 'map(.{{key_name}})'

• Output the value of multiple keys as a new JSON object (assuming the input JSON has the keys key_name and other_key_name):

cat {{file.json}} | jq '{{{my_new_key}}: .{{key_name}}, {{my_other_key}}: {{other_key_name}}}'

• Combine multiple filters:

cat {{file.json}} | jq 'unique | sort | reverse'

• Output the value of a given key to a string (and disable JSON output):

cat {{file.json}} | jq --raw-output '"some text: \(.{{key_name}})"'