[json] How to get key names from JSON using jq

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

The above command outputs only the values as below:

"[email protected]"

"2323"

"test"

"02-03-2014-13:41"

"application"

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

email

versionID

context

date

versionName

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

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

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;

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"

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

ab
cd

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'

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"