Use jq

jq is an JSON command-line processor.

Check: jq GitHub repository

You can use it to prettify your JSON

jq '.' < foo-ugly.json > foo-pretty.json

Tip from @chriswinters via Twitter

Or in conjuction with curl. A nifty alternative is httpie (http).

curl http://jsonplaceholder.typicode.com/posts/1 |jq

{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}

Source used in example: http://jsonplaceholder.typicode.com/

You can with luck install jq via Homebrew.

jq however can do so much more, one of my colleagues requested a list of all of the postal codes in Denmark, these are available in a quite extensive data structure, but since we just needed the postal code, we needed to parse the data - jq to the rescue - inspired by this blog post by Jesus Galvan, I knew I could get jq to do what I needed.

Example snippet of data structure:

[
{
  "href": "https://api.dataforsyningen.dk/postnumre/1050",
  "nr": "1050",
  "navn": "København K",
  "stormodtageradresser": null,
  "bbox": [
    12.5841266,
    55.67871944,
    12.58827962,
    55.68185111
  ],
  "visueltcenter": [
    12.58600133,
    55.68065246
  ],
  "kommuner": [
    {
      "href": "https://api.dataforsyningen.dk/kommuner/0101",
      "kode": "0101",
      "navn": "København"
    }
  ],
  "ændret": "2018-04-30T15:23:13.528Z",
  "geo_ændret": "2014-11-04T16:01:00.879Z",
  "geo_version": 1,
  "dagi_id": "191050"
}, {
  "href": "https://api.dataforsyningen.dk/postnumre/1051",
  "nr": "1051",
  "navn": "København K",
  "stormodtageradresser": null,
  "bbox": [
    12.58727138,
    55.67873773,
    12.59417472,
    55.68095605
  ],
  "visueltcenter": [
    12.59022696,
...

I can recommend downloading the resource to a JSON file, when experimenting/developing, since it is easier to work with.

curl --output data.json https://api.dataforsyningen.dk/postnumre

So what we want to accomplish is to:

1. Extract data from an online resource
2. Extract only the postal codes, no JSON
3. And finally teach my colleague to fish

Result:

http https://api.dataforsyningen.dk/postnumre |jq --raw-output '.[] | .nr'

Se we have switched to httpie (http).

1. we pipe the data from the request to jq
2. we request that jq emit raw output via --raw-output
3. we interpret the data as an array using .[] and pipe it in jq context to the next match
4. we locate the key nr

zsh> http https://api.dataforsyningen.dk/postnumre |jq --raw-output '.[] | .nr' |head -n 20
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069

Resources and References

• jq Website
• jq playground
• GitHub repository: jq
• Blog post by Jesus Galvan
• Blog post by Ganest Chandrasekaran: “Parse JSON easily like a PRO”
• Gist: jq cheatsheet a gist
• LZone: jq cheatsheet some HTML
• Zendesk: jq cheatsheet some good fundamental examples