Iterate over JSON string with Bash

Question

I'm building a script to process JSON for specifc Chef/node data. I need to get the name of each object as it will be different every time. Typically I use jsawk but this is only helpful if you know the name of the object.

A solution should work on either of the below examples:

{"keepalived":{"role":"MASTER","vip":"192.168.4.113"},"mysql":{"service_name":"singularitydb"},"haproxy":{"role":"MASTER"}}

Should return: keepalived,mysql,haproxy

{"nginx":{"attribute":"standalone"},"haproxy":{"role":"MASTER"}}

Should return: nginx,haproxy

chepner · Accepted Answer · 2016-06-24 19:35:00Z

5

Use jq:

echo "$JSON" | jq 'keys'

answered Jun 24, 2016 at 19:35

chepner

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4 Comments

Krzysztof Krasoń Over a year ago

it won't work for objects inside objects, but maybe author doesn't need that

chepner Over a year ago

Neither example indicates that is required. Both ask for the top-level keys of an object.

user3063045 Over a year ago

I'll give it to you for introducing me to jq...but i really wanted to iterate over the keys. Did it with this:

jslength=$(echo $attributes | jq 'keys | length') 	for ((i=0; i<$jslength; i++)); do 		result=$(echo $attributes | jq 'keys' | jq ".[$i]") 		echo $result 	done

chepner Over a year ago

You should be clearer about what you ask for: echo "$attributes" | jq 'keys | .[]' is the equivalent of the code in your comment. Depending on what you actually want to do with each key while iterating, there may also be something in jq you can use.

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