shell - How to get key names from JSON using jq

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Top 5 Answer for shell - How to get key names from JSON using jq

vote vote

99

You can use:

jq 'keys' file.json 

Complete example

$ cat file.json { "Archiver-Version" : "Plexus Archiver", "Build-Id" : "", "Build-Jdk" : "1.7.0_07", "Build-Number" : "", "Build-Tag" : "", "Built-By" : "cporter", "Created-By" : "Apache Maven", "Implementation-Title" : "northstar", "Implementation-Vendor-Id" : "com.test.testPack", "Implementation-Version" : "testBox", "Manifest-Version" : "1.0", "appname" : "testApp", "build-date" : "02-03-2014-13:41", "version" : "testBox" }  $ jq 'keys' file.json [   "Archiver-Version",   "Build-Id",   "Build-Jdk",   "Build-Number",   "Build-Tag",   "Built-By",   "Created-By",   "Implementation-Title",   "Implementation-Vendor-Id",   "Implementation-Version",   "Manifest-Version",   "appname",   "build-date",   "version" ] 

UPDATE: To create a BASH array using these keys:

Using BASH 4+:

mapfile -t arr < <(jq -r 'keys[]' ms.json) 

On older BASH you can do:

arr=() while IFS='' read -r line; do    arr+=("$line") done < <(jq 'keys[]' ms.json) 

Then print it:

printf "%s\n" ${arr[@]}  "Archiver-Version" "Build-Id" "Build-Jdk" "Build-Number" "Build-Tag" "Built-By" "Created-By" "Implementation-Title" "Implementation-Vendor-Id" "Implementation-Version" "Manifest-Version" "appname" "build-date" "version" 
vote vote

87

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" 
vote vote

76

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

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

65

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; 
vote vote

60

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" 

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