How to get key names from JSON using jq

Question

curl http://testhost.test.com:8080/application/app/version | jq '.version' | jq '.[]'

The above command outputs only the values as below:

"madireddy@test.com"

"2323"

"test"

"02-03-2014-13:41"

"application"

How can I get the key names instead like the below:

email

versionID

context

date

versionName

score 359 · Accepted Answer · edited Feb 07 '23 at 19:16

359

To get the keys in the order they appear in the original JSON use:

jq 'keys_unsorted' file.json

If you want the keys sorted alphanumerically, you can use:

jq 'keys' file.json

Complete example

$ cat file.json
{ "Created-By" : "Apache Maven", "Build-Number" : "", "Archiver-Version" : "Plexus Archiver", "Build-Id" : "",  "Build-Tag" : "", "Built-By" : "cporter"}

$ jq 'keys_unsorted' file.json                                         
[
  "Created-By",
  "Build-Number",
  "Archiver-Version",
  "Build-Id",
  "Build-Tag",
  "Built-By"
]

$ jq 'keys' file.json
[
  "Archiver-Version",
  "Build-Id",
  "Build-Number",
  "Build-Tag",
  "Built-By",
  "Created-By"
]

edited Feb 07 '23 at 19:16

Cornelius Roemer

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answered Apr 16 '14 at 19:36

anubhava

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I'd correct the answer to `jq 'keys | sort' …` for better visibility. – AnrDaemon Nov 23 '22 at 08:47
Beware that `jq 'keys'` sorts the keys before outputting them, this may not be what the user expects. – Cornelius Roemer Feb 07 '23 at 19:09
1

@AnrDaemon `'keys'` sorts already by default. For unsorted results (which is what I needed, use `'keys_unsorted'` – Cornelius Roemer Feb 07 '23 at 19:17
1

@CorneliusRoemer" Many thanks for pointing this out and your edit to answer. – anubhava Feb 07 '23 at 19:19
1

@CorneliusRoemer thank you very much for pointing that out. I did not notice that at the first glance. – AnrDaemon Feb 09 '23 at 09:00
This is great when an API returns you something gigantic and you have to scroll up to find the name of the field at the beginning of the object. – Sridhar Sarnobat May 17 '23 at 23:17
I wonder if there's an equivalent for only a sub-json object. It only works on the top-level object. – Sridhar Sarnobat May 17 '23 at 23:20

Gianfranco P. · Answer 2 · 2021-03-21T10:49:23.753

77

To get the keys on a deeper node in a JSON:

echo '{"data": "1", "user": { "name": 2, "phone": 3 } }' | jq '.user | keys[]'
"name"
"phone"

edited Mar 21 '21 at 10:49

answered May 21 '20 at 14:38

Gianfranco P.

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This one is a bit better than the accepted answer, as it demonstrates how to use | within a jq expression, rather than piping output through several instances of jq – tschaible Oct 11 '21 at 13:07

Chris Stryczynski · Answer 3 · 2017-11-20T19:05:29.690

43

You need to use jq 'keys[]'. For example:

echo '{"example1" : 1, "example2" : 2, "example3" : 3}' | jq 'keys[]'

Will output a line separated list:

"example1"
"example2"
"example3"

edited Nov 20 '17 at 19:05

answered Jul 06 '17 at 18:21

Chris Stryczynski

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Elliot Pahl · Answer 4 · 2017-06-29T04:32:09.833

18

In combination with the above answer, you want to ask jq for raw output, so your last filter should be eg.:

     cat input.json | jq -r 'keys'

From jq help:

     -r     output raw strings, not JSON texts;

edited Jun 29 '17 at 04:32

answered Jun 28 '17 at 06:55

Elliot Pahl

181
1
3

score 13 · Answer 5 · answered Apr 25 '21 at 06:45

13

If your input is an array of objects,

[
  { 
    "a01" : { "name" : "A", "user" : "B" }
  },
  { 
    "a02" : { "name" : "C", "user" : "D" }
  }
]

try with:

jq '.[] | keys[]'

answered Apr 25 '21 at 06:45

freedev

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nrb · Answer 6 · 2019-01-13T00:39:11.557

11

To print keys on one line as csv:

echo '{"b":"2","a":"1"}' | jq -r 'keys | [ .[] | tostring ] | @csv'

Output:

"a","b"

For csv completeness ... to print values on one line as csv:

echo '{"b":"2","a":"1"}' | jq -rS . | jq -r '. | [ .[] | tostring ] | @csv'

Output:

"1","2"

edited Jan 13 '19 at 00:39

answered Jan 13 '19 at 00:01

nrb

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5

score 10 · Answer 7 · answered Apr 29 '21 at 15:42

10

Oddly enough, the accepted answer doesn’t actually answer the Q exactly, so for reference, here is a solution that does:

$ jq -r 'keys_unsorted[]' file.json

answered Apr 29 '21 at 15:42

peak

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This is the only one that worked for me. I spend over 6 hours just on this issue. Thank you! You can also use a JSON varaible too using: `declare -a MASTER_KEYS_LIST=($(jq -r 'keys_unsorted[]' <<< "${JSON_OBJECT_VAR}"))` – Jeremy May 22 '22 at 14:53
Yep, this is the only one that doesn't change the order of your keys. Though the `[]` seems unnecessary. This works for me `jq 'keys_unsorted' file.json` – Cornelius Roemer Feb 07 '23 at 19:05
@peak thanks for this proper solution, I edited the accepted answer to add `keys_unsorted` and made the example data show the difference (OP used sorted keys which hid the difference between keys and keys_unsorted) – Cornelius Roemer Feb 07 '23 at 19:18

score 6 · Answer 8 · answered Jan 11 '19 at 19:45

6

echo '{"ab": 1, "cd": 2}' | jq -r 'keys[]' prints all keys one key per line without quotes.

ab
cd

answered Jan 11 '19 at 19:45

hrushikesh

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score 2 · Answer 9 · answered Apr 27 '20 at 16:48

Here's another way of getting a Bash array with the example JSON given by @anubhava in his answer:

arr=($(jq --raw-output 'keys_unsorted | @sh' file.json))

echo ${arr[0]}    # 'Archiver-Version'
echo ${arr[1]}    # 'Build-Id'
echo ${arr[2]}    # 'Build-Jdk'

How to get key names from JSON using jq

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