Using jq to fetch key value from json output

问题:

I have a file that looks as below:

{
  "repositories": [
   {
    "id": "156c48fc-f208-43e8-a631-4d12deb89fa4",
    "namespace": "rhel12",
    "namespaceType": "organization",
    "name": "rhel6.6",
    "shortDescription": "",
    "visibility": "public"
   },
   {
    "id": "f359b5d2-cb3a-4bb3-8aff-d879d51f1a04",
    "namespace": "rhel12",
    "namespaceType": "organization",
    "name": "rhel7",
    "shortDescription": "",
    "visibility": "public"
   }
  ]
 }

I want to get only name values with each of them in a new line so that I can use while read -r line. I need only

rhel6.6 
rhel7

I am using jq as follows which doesn't seem to work:

jq -r '.[].name'

Please suggest correct use of jq here

回答1:

You need to combine filters by means of | operator:

$ jq -r '.[] | .[] | .name' test.json 
rhel6.6
rhel7

The first .[] fetches repositories array. The next .[] fetches all the items of the repositories array. Finally, .name extracts properties from the array items(objects).

Note, the first .[] works on object because it is a documented feature:

.[]
    If you use the .[index] syntax, but omit the index entirely, it
    will return all of the elements of an array...

    You can also use this on an object, and it will return all the
    values of the object.

回答2:

You want to look at the repositories array instead of treating the input as an array:

$ jq -r '.repositories[].name' file
rhel6.6
rhel7

回答3:

Here is another solution. Assuming the requirements

I want to get only name values with each of them in a new line so that I can use while read -r line.

Can you please how can i get output in format rhel12/rhel6.6 In other words, I need o/p in format namespace/name

if the data is in data.json then the command

jq -M -r '.repositories[] | "\(.namespace)/\(.name)"' data.json

should produce

rhel12/rhel6.6
rhel12/rhel7