[SOLVED] How to select multiple items with duplicate items using jq?

Issue

I have a JSON file which contains a list like this;

[{
    "host": "cat",
    "ip": "192.168.1.1",
    "id": "cherry"
}, {
    "host": "dog",
    "ip": "192.168.1.1",
    "id": "apple"
}, {
    "host": "cat",
    "ip": "192.168.1.2",
    "id": "banana"
}]

I want to collect IPs and print id and host next to it but if IP is used multiple times then print multiple id and host next to instead of a new line. IP and host can be the same for multiple items but id is unique.

So the final output should look like this;

$ echo <something>
192.168.1.1 cat cherry dog apple
192.168.1.2 cat banana

How can I do this using bash and jq?

Solution

Make sure you have a valid JSON file: Remove the last comma , in each object to get this as your input.json:

[{
    "host": "cat",
    "ip": "192.168.1.1",
    "id": "cherry"
}, {
    "host": "dog",
    "ip": "192.168.1.1",
    "id": "apple"
}, {
    "host": "cat",
    "ip": "192.168.1.2",
    "id": "banana"
}]

Then, you only need one jq call:

jq --raw-output 'group_by(.ip)[] | [first.ip, (.[] | .host, .id)] | join(" ")' input.json

Demo

Answered By - pmf