tldr/pages/common/jq.md

41 lines
1.2 KiB
Markdown
Raw Normal View History

2016-12-21 23:40:12 +00:00
# jq
> A command-line JSON processor that uses a domain-specific language.
2019-06-05 08:55:42 +01:00
> More information: <https://stedolan.github.io/jq>.
2016-12-21 23:40:12 +00:00
2017-05-04 09:35:38 +01:00
- Output a JSON file, in pretty-print format:
2016-12-21 23:40:12 +00:00
`jq . {{file.json}}`
2016-12-21 23:40:12 +00:00
2017-05-04 09:35:38 +01:00
- Output all elements from arrays (or all key-value pairs from objects) in a JSON file:
2016-12-21 23:40:12 +00:00
`jq '.[]' {{file.json}}`
2016-12-21 23:40:12 +00:00
2017-05-04 09:35:38 +01:00
- Read JSON objects from a file into an array, and output it (inverse of `jq .[]`):
2016-12-21 23:40:12 +00:00
`jq --slurp . {{file.json}}`
2016-12-21 23:40:12 +00:00
2017-05-04 09:35:38 +01:00
- Output the first element in a JSON file:
2016-12-21 23:40:12 +00:00
`jq '.[0]' {{file.json}}`
2016-12-21 23:40:12 +00:00
- Output the value of a given key of the first element in a JSON text from `stdin`:
2016-12-21 23:40:12 +00:00
`cat {{file.json}} | jq '.[0].{{key_name}}'`
2016-12-21 23:40:12 +00:00
- Output the value of a given key of each element in a JSON text from `stdin`:
2016-12-21 23:40:12 +00:00
`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`):
2020-08-11 16:49:43 +01:00
`cat {{file.json}} | jq '{{{my_new_key}}: .{{key_name}}, {{my_other_key}}: .{{other_key_name}}}'`
- Combine multiple filters:
2019-04-18 06:45:39 +01:00
`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}})"'`