jqコマンドでJSONを操作・分析する

どうもoreoです。

今回はJSONからの値取得、集計、整形などができるjqコマンドについて記載します！JSONを分析する際に大活躍です。

1 下準備

1-1 使用するJSONデータ

Star WarsAPIから取得したこちらのデータをjqコマンドでいじってみたいと思います。

people.json

{
  "count": 82,
  "next": "https://swapi.dev/api/people/?page=2",
  "previous": null,
  "results": [
    {
      "name": "Luke Skywalker",
      "height": "172",
      "mass": "77",
      "hair_color": "blond",
      "skin_color": "fair",
      "eye_color": "blue",
      "birth_year": "19BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [
        "https://swapi.dev/api/vehicles/14/",
        "https://swapi.dev/api/vehicles/30/"
      ],
      "starships": [
        "https://swapi.dev/api/starships/12/",
        "https://swapi.dev/api/starships/22/"
      ],
      "created": "2014-12-09T13:50:51.644000Z",
      "edited": "2014-12-20T21:17:56.891000Z",
      "url": "https://swapi.dev/api/people/1/"
    },
    {
      "name": "C-3PO",
      "height": "167",
      "mass": "75",
      "hair_color": "n/a",
      "skin_color": "gold",
      "eye_color": "yellow",
      "birth_year": "112BBY",
      "gender": "n/a",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/4/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": ["https://swapi.dev/api/species/2/"],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:10:51.357000Z",
      "edited": "2014-12-20T21:17:50.309000Z",
      "url": "https://swapi.dev/api/people/2/"
    },
    {
      "name": "R2-D2",
      "height": "96",
      "mass": "32",
      "hair_color": "n/a",
      "skin_color": "white, blue",
      "eye_color": "red",
      "birth_year": "33BBY",
      "gender": "n/a",
      "homeworld": "https://swapi.dev/api/planets/8/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/4/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": ["https://swapi.dev/api/species/2/"],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:11:50.376000Z",
      "edited": "2014-12-20T21:17:50.311000Z",
      "url": "https://swapi.dev/api/people/3/"
    },
    {
      "name": "Darth Vader",
      "height": "202",
      "mass": "136",
      "hair_color": "none",
      "skin_color": "white",
      "eye_color": "yellow",
      "birth_year": "41.9BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [],
      "starships": ["https://swapi.dev/api/starships/13/"],
      "created": "2014-12-10T15:18:20.704000Z",
      "edited": "2014-12-20T21:17:50.313000Z",
      "url": "https://swapi.dev/api/people/4/"
    },
    {
      "name": "Leia Organa",
      "height": "150",
      "mass": "49",
      "hair_color": "brown",
      "skin_color": "light",
      "eye_color": "brown",
      "birth_year": "19BBY",
      "gender": "female",
      "homeworld": "https://swapi.dev/api/planets/2/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": ["https://swapi.dev/api/vehicles/30/"],
      "starships": [],
      "created": "2014-12-10T15:20:09.791000Z",
      "edited": "2014-12-20T21:17:50.315000Z",
      "url": "https://swapi.dev/api/people/5/"
    },
    {
      "name": "Owen Lars",
      "height": "178",
      "mass": "120",
      "hair_color": "brown, grey",
      "skin_color": "light",
      "eye_color": "blue",
      "birth_year": "52BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:52:14.024000Z",
      "edited": "2014-12-20T21:17:50.317000Z",
      "url": "https://swapi.dev/api/people/6/"
    },
    {
      "name": "Beru Whitesun lars",
      "height": "165",
      "mass": "75",
      "hair_color": "brown",
      "skin_color": "light",
      "eye_color": "blue",
      "birth_year": "47BBY",
      "gender": "female",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:53:41.121000Z",
      "edited": "2014-12-20T21:17:50.319000Z",
      "url": "https://swapi.dev/api/people/7/"
    },
    {
      "name": "R5-D4",
      "height": "97",
      "mass": "32",
      "hair_color": "n/a",
      "skin_color": "white, red",
      "eye_color": "red",
      "birth_year": "unknown",
      "gender": "n/a",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": ["https://swapi.dev/api/films/1/"],
      "species": ["https://swapi.dev/api/species/2/"],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:57:50.959000Z",
      "edited": "2014-12-20T21:17:50.321000Z",
      "url": "https://swapi.dev/api/people/8/"
    },
    {
      "name": "Biggs Darklighter",
      "height": "183",
      "mass": "84",
      "hair_color": "black",
      "skin_color": "light",
      "eye_color": "brown",
      "birth_year": "24BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": ["https://swapi.dev/api/films/1/"],
      "species": [],
      "vehicles": [],
      "starships": ["https://swapi.dev/api/starships/12/"],
      "created": "2014-12-10T15:59:50.509000Z",
      "edited": "2014-12-20T21:17:50.323000Z",
      "url": "https://swapi.dev/api/people/9/"
    },
    {
      "name": "Obi-Wan Kenobi",
      "height": "182",
      "mass": "77",
      "hair_color": "auburn, white",
      "skin_color": "fair",
      "eye_color": "blue-gray",
      "birth_year": "57BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/20/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/4/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": ["https://swapi.dev/api/vehicles/38/"],
      "starships": [
        "https://swapi.dev/api/starships/48/",
        "https://swapi.dev/api/starships/59/",
        "https://swapi.dev/api/starships/64/",
        "https://swapi.dev/api/starships/65/",
        "https://swapi.dev/api/starships/74/"
      ],
      "created": "2014-12-10T16:16:29.192000Z",
      "edited": "2014-12-20T21:17:50.325000Z",
      "url": "https://swapi.dev/api/people/10/"
    }
  ]
}

1-2 jqコマンドのインストール

brew install jq

2 使い方

2-1 基本

.で全てのJSONデータを取得できます。今回は元々整形されているので意味はありませんが、jq .でJSONデータが整形されます。

cat people.json | jq .

実行結果

{
  "count": 82,
  "next": "https://swapi.dev/api/people/?page=2",
  "previous": null,
  "results": [
    {
      "name": "Luke Skywalker",
      "height": "172",
      "mass": "77",
      "hair_color": "blond",
      "skin_color": "fair",
      "eye_color": "blue",
      "birth_year": "19BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [
        "https://swapi.dev/api/vehicles/14/",
        "https://swapi.dev/api/vehicles/30/"
      ],
      "starships": [
        "https://swapi.dev/api/starships/12/",
        "https://swapi.dev/api/starships/22/"
      ],
      "created": "2014-12-09T13:50:51.644000Z",
      "edited": "2014-12-20T21:17:56.891000Z",
      "url": "https://swapi.dev/api/people/1/"
    },
    {
      "name": "C-3PO",
      "height": "167",
      "mass": "75",
      "hair_color": "n/a",
      "skin_color": "gold",
      "eye_color": "yellow",
      "birth_year": "112BBY",
      "gender": "n/a",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/4/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [
        "https://swapi.dev/api/species/2/"
      ],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:10:51.357000Z",
      "edited": "2014-12-20T21:17:50.309000Z",
      "url": "https://swapi.dev/api/people/2/"
    },
    {
      "name": "R2-D2",
      "height": "96",
      "mass": "32",
      "hair_color": "n/a",
      "skin_color": "white, blue",
      "eye_color": "red",
      "birth_year": "33BBY",
      "gender": "n/a",
      "homeworld": "https://swapi.dev/api/planets/8/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/4/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [
        "https://swapi.dev/api/species/2/"
      ],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:11:50.376000Z",
      "edited": "2014-12-20T21:17:50.311000Z",
      "url": "https://swapi.dev/api/people/3/"
    },
    {
      "name": "Darth Vader",
      "height": "202",
      "mass": "136",
      "hair_color": "none",
      "skin_color": "white",
      "eye_color": "yellow",
      "birth_year": "41.9BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [],
      "starships": [
        "https://swapi.dev/api/starships/13/"
      ],
      "created": "2014-12-10T15:18:20.704000Z",
      "edited": "2014-12-20T21:17:50.313000Z",
      "url": "https://swapi.dev/api/people/4/"
    },
    {
      "name": "Leia Organa",
      "height": "150",
      "mass": "49",
      "hair_color": "brown",
      "skin_color": "light",
      "eye_color": "brown",
      "birth_year": "19BBY",
      "gender": "female",
      "homeworld": "https://swapi.dev/api/planets/2/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [
        "https://swapi.dev/api/vehicles/30/"
      ],
      "starships": [],
      "created": "2014-12-10T15:20:09.791000Z",
      "edited": "2014-12-20T21:17:50.315000Z",
      "url": "https://swapi.dev/api/people/5/"
    },
    {
      "name": "Owen Lars",
      "height": "178",
      "mass": "120",
      "hair_color": "brown, grey",
      "skin_color": "light",
      "eye_color": "blue",
      "birth_year": "52BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:52:14.024000Z",
      "edited": "2014-12-20T21:17:50.317000Z",
      "url": "https://swapi.dev/api/people/6/"
    },
    {
      "name": "Beru Whitesun lars",
      "height": "165",
      "mass": "75",
      "hair_color": "brown",
      "skin_color": "light",
      "eye_color": "blue",
      "birth_year": "47BBY",
      "gender": "female",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:53:41.121000Z",
      "edited": "2014-12-20T21:17:50.319000Z",
      "url": "https://swapi.dev/api/people/7/"
    },
    {
      "name": "R5-D4",
      "height": "97",
      "mass": "32",
      "hair_color": "n/a",
      "skin_color": "white, red",
      "eye_color": "red",
      "birth_year": "unknown",
      "gender": "n/a",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/"
      ],
      "species": [
        "https://swapi.dev/api/species/2/"
      ],
      "vehicles": [],
      "starships": [],
      "created": "2014-12-10T15:57:50.959000Z",
      "edited": "2014-12-20T21:17:50.321000Z",
      "url": "https://swapi.dev/api/people/8/"
    },
    {
      "name": "Biggs Darklighter",
      "height": "183",
      "mass": "84",
      "hair_color": "black",
      "skin_color": "light",
      "eye_color": "brown",
      "birth_year": "24BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/1/",
      "films": [
        "https://swapi.dev/api/films/1/"
      ],
      "species": [],
      "vehicles": [],
      "starships": [
        "https://swapi.dev/api/starships/12/"
      ],
      "created": "2014-12-10T15:59:50.509000Z",
      "edited": "2014-12-20T21:17:50.323000Z",
      "url": "https://swapi.dev/api/people/9/"
    },
    {
      "name": "Obi-Wan Kenobi",
      "height": "182",
      "mass": "77",
      "hair_color": "auburn, white",
      "skin_color": "fair",
      "eye_color": "blue-gray",
      "birth_year": "57BBY",
      "gender": "male",
      "homeworld": "https://swapi.dev/api/planets/20/",
      "films": [
        "https://swapi.dev/api/films/1/",
        "https://swapi.dev/api/films/2/",
        "https://swapi.dev/api/films/3/",
        "https://swapi.dev/api/films/4/",
        "https://swapi.dev/api/films/5/",
        "https://swapi.dev/api/films/6/"
      ],
      "species": [],
      "vehicles": [
        "https://swapi.dev/api/vehicles/38/"
      ],
      "starships": [
        "https://swapi.dev/api/starships/48/",
        "https://swapi.dev/api/starships/59/",
        "https://swapi.dev/api/starships/64/",
        "https://swapi.dev/api/starships/65/",
        "https://swapi.dev/api/starships/74/"
      ],
      "created": "2014-12-10T16:16:29.192000Z",
      "edited": "2014-12-20T21:17:50.325000Z",
      "url": "https://swapi.dev/api/people/10/"
    }
  ]
}

-cオプションで整形無しの形で出力できます。

cat people.json | jq -c .

実行結果

{"count":82,"next":"https://swapi.dev/api/people/?page=2","previous":null,"results":[{"name":"Luke Skywalker","height":"172","mass":"77","hair_color":"blond","skin_color":"fair","eye_color":"blue","birth_year":"19BBY","gender":"male","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/2/","https://swapi.dev/api/films/3/","https://swapi.dev/api/films/6/"],"species":[],"vehicles":["https://swapi.dev/api/vehicles/14/","https://swapi.dev/api/vehicles/30/"],"starships":["https://swapi.dev/api/starships/12/","https://swapi.dev/api/starships/22/"],"created":"2014-12-09T13:50:51.644000Z","edited":"2014-12-20T21:17:56.891000Z","url":"https://swapi.dev/api/people/1/"},{"name":"C-3PO","height":"167","mass":"75","hair_color":"n/a","skin_color":"gold","eye_color":"yellow","birth_year":"112BBY","gender":"n/a","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/2/","https://swapi.dev/api/films/3/","https://swapi.dev/api/films/4/","https://swapi.dev/api/films/5/","https://swapi.dev/api/films/6/"],"species":["https://swapi.dev/api/species/2/"],"vehicles":[],"starships":[],"created":"2014-12-10T15:10:51.357000Z","edited":"2014-12-20T21:17:50.309000Z","url":"https://swapi.dev/api/people/2/"},{"name":"R2-D2","height":"96","mass":"32","hair_color":"n/a","skin_color":"white, blue","eye_color":"red","birth_year":"33BBY","gender":"n/a","homeworld":"https://swapi.dev/api/planets/8/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/2/","https://swapi.dev/api/films/3/","https://swapi.dev/api/films/4/","https://swapi.dev/api/films/5/","https://swapi.dev/api/films/6/"],"species":["https://swapi.dev/api/species/2/"],"vehicles":[],"starships":[],"created":"2014-12-10T15:11:50.376000Z","edited":"2014-12-20T21:17:50.311000Z","url":"https://swapi.dev/api/people/3/"},{"name":"Darth Vader","height":"202","mass":"136","hair_color":"none","skin_color":"white","eye_color":"yellow","birth_year":"41.9BBY","gender":"male","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/2/","https://swapi.dev/api/films/3/","https://swapi.dev/api/films/6/"],"species":[],"vehicles":[],"starships":["https://swapi.dev/api/starships/13/"],"created":"2014-12-10T15:18:20.704000Z","edited":"2014-12-20T21:17:50.313000Z","url":"https://swapi.dev/api/people/4/"},{"name":"Leia Organa","height":"150","mass":"49","hair_color":"brown","skin_color":"light","eye_color":"brown","birth_year":"19BBY","gender":"female","homeworld":"https://swapi.dev/api/planets/2/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/2/","https://swapi.dev/api/films/3/","https://swapi.dev/api/films/6/"],"species":[],"vehicles":["https://swapi.dev/api/vehicles/30/"],"starships":[],"created":"2014-12-10T15:20:09.791000Z","edited":"2014-12-20T21:17:50.315000Z","url":"https://swapi.dev/api/people/5/"},{"name":"Owen Lars","height":"178","mass":"120","hair_color":"brown, grey","skin_color":"light","eye_color":"blue","birth_year":"52BBY","gender":"male","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/5/","https://swapi.dev/api/films/6/"],"species":[],"vehicles":[],"starships":[],"created":"2014-12-10T15:52:14.024000Z","edited":"2014-12-20T21:17:50.317000Z","url":"https://swapi.dev/api/people/6/"},{"name":"Beru Whitesun lars","height":"165","mass":"75","hair_color":"brown","skin_color":"light","eye_color":"blue","birth_year":"47BBY","gender":"female","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/5/","https://swapi.dev/api/films/6/"],"species":[],"vehicles":[],"starships":[],"created":"2014-12-10T15:53:41.121000Z","edited":"2014-12-20T21:17:50.319000Z","url":"https://swapi.dev/api/people/7/"},{"name":"R5-D4","height":"97","mass":"32","hair_color":"n/a","skin_color":"white, red","eye_color":"red","birth_year":"unknown","gender":"n/a","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/"],"species":["https://swapi.dev/api/species/2/"],"vehicles":[],"starships":[],"created":"2014-12-10T15:57:50.959000Z","edited":"2014-12-20T21:17:50.321000Z","url":"https://swapi.dev/api/people/8/"},{"name":"Biggs Darklighter","height":"183","mass":"84","hair_color":"black","skin_color":"light","eye_color":"brown","birth_year":"24BBY","gender":"male","homeworld":"https://swapi.dev/api/planets/1/","films":["https://swapi.dev/api/films/1/"],"species":[],"vehicles":[],"starships":["https://swapi.dev/api/starships/12/"],"created":"2014-12-10T15:59:50.509000Z","edited":"2014-12-20T21:17:50.323000Z","url":"https://swapi.dev/api/people/9/"},{"name":"Obi-Wan Kenobi","height":"182","mass":"77","hair_color":"auburn, white","skin_color":"fair","eye_color":"blue-gray","birth_year":"57BBY","gender":"male","homeworld":"https://swapi.dev/api/planets/20/","films":["https://swapi.dev/api/films/1/","https://swapi.dev/api/films/2/","https://swapi.dev/api/films/3/","https://swapi.dev/api/films/4/","https://swapi.dev/api/films/5/","https://swapi.dev/api/films/6/"],"species":[],"vehicles":["https://swapi.dev/api/vehicles/38/"],"starships":["https://swapi.dev/api/starships/48/","https://swapi.dev/api/starships/59/","https://swapi.dev/api/starships/64/","https://swapi.dev/api/starships/65/","https://swapi.dev/api/starships/74/"],"created":"2014-12-10T16:16:29.192000Z","edited":"2014-12-20T21:17:50.325000Z","url":"https://swapi.dev/api/people/10/"}]}

特定の要素を取得したい場合は、'.特定の要素名'で取得できます。

cat people.json | jq '.count'

実行結果

 82

2-2 配列操作

配列の要素を取得する場合は、'.配列の要素名[]'で取得できます。

cat people.json | jq '.results[]'

実行結果

{
  "name": "Luke Skywalker",
  "height": "172",
  "mass": "77",
  "hair_color": "blond",
  "skin_color": "fair",
  "eye_color": "blue",
  "birth_year": "19BBY",
  "gender": "male",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [],
  "vehicles": [
    "https://swapi.dev/api/vehicles/14/",
    "https://swapi.dev/api/vehicles/30/"
  ],
  "starships": [
    "https://swapi.dev/api/starships/12/",
    "https://swapi.dev/api/starships/22/"
  ],
  "created": "2014-12-09T13:50:51.644000Z",
  "edited": "2014-12-20T21:17:56.891000Z",
  "url": "https://swapi.dev/api/people/1/"
}
{
  "name": "C-3PO",
  "height": "167",
  "mass": "75",
  "hair_color": "n/a",
  "skin_color": "gold",
  "eye_color": "yellow",
  "birth_year": "112BBY",
  "gender": "n/a",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/4/",
    "https://swapi.dev/api/films/5/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [
    "https://swapi.dev/api/species/2/"
  ],
  "vehicles": [],
  "starships": [],
  "created": "2014-12-10T15:10:51.357000Z",
  "edited": "2014-12-20T21:17:50.309000Z",
  "url": "https://swapi.dev/api/people/2/"
}
{
  "name": "R2-D2",
  "height": "96",
  "mass": "32",
  "hair_color": "n/a",
  "skin_color": "white, blue",
  "eye_color": "red",
  "birth_year": "33BBY",
  "gender": "n/a",
  "homeworld": "https://swapi.dev/api/planets/8/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/4/",
    "https://swapi.dev/api/films/5/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [
    "https://swapi.dev/api/species/2/"
  ],
  "vehicles": [],
  "starships": [],
  "created": "2014-12-10T15:11:50.376000Z",
  "edited": "2014-12-20T21:17:50.311000Z",
  "url": "https://swapi.dev/api/people/3/"
}
{
  "name": "Darth Vader",
  "height": "202",
  "mass": "136",
  "hair_color": "none",
  "skin_color": "white",
  "eye_color": "yellow",
  "birth_year": "41.9BBY",
  "gender": "male",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [],
  "vehicles": [],
  "starships": [
    "https://swapi.dev/api/starships/13/"
  ],
  "created": "2014-12-10T15:18:20.704000Z",
  "edited": "2014-12-20T21:17:50.313000Z",
  "url": "https://swapi.dev/api/people/4/"
}
{
  "name": "Leia Organa",
  "height": "150",
  "mass": "49",
  "hair_color": "brown",
  "skin_color": "light",
  "eye_color": "brown",
  "birth_year": "19BBY",
  "gender": "female",
  "homeworld": "https://swapi.dev/api/planets/2/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [],
  "vehicles": [
    "https://swapi.dev/api/vehicles/30/"
  ],
  "starships": [],
  "created": "2014-12-10T15:20:09.791000Z",
  "edited": "2014-12-20T21:17:50.315000Z",
  "url": "https://swapi.dev/api/people/5/"
}
{
  "name": "Owen Lars",
  "height": "178",
  "mass": "120",
  "hair_color": "brown, grey",
  "skin_color": "light",
  "eye_color": "blue",
  "birth_year": "52BBY",
  "gender": "male",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/5/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [],
  "vehicles": [],
  "starships": [],
  "created": "2014-12-10T15:52:14.024000Z",
  "edited": "2014-12-20T21:17:50.317000Z",
  "url": "https://swapi.dev/api/people/6/"
}
{
  "name": "Beru Whitesun lars",
  "height": "165",
  "mass": "75",
  "hair_color": "brown",
  "skin_color": "light",
  "eye_color": "blue",
  "birth_year": "47BBY",
  "gender": "female",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/5/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [],
  "vehicles": [],
  "starships": [],
  "created": "2014-12-10T15:53:41.121000Z",
  "edited": "2014-12-20T21:17:50.319000Z",
  "url": "https://swapi.dev/api/people/7/"
}
{
  "name": "R5-D4",
  "height": "97",
  "mass": "32",
  "hair_color": "n/a",
  "skin_color": "white, red",
  "eye_color": "red",
  "birth_year": "unknown",
  "gender": "n/a",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/"
  ],
  "species": [
    "https://swapi.dev/api/species/2/"
  ],
  "vehicles": [],
  "starships": [],
  "created": "2014-12-10T15:57:50.959000Z",
  "edited": "2014-12-20T21:17:50.321000Z",
  "url": "https://swapi.dev/api/people/8/"
}
{
  "name": "Biggs Darklighter",
  "height": "183",
  "mass": "84",
  "hair_color": "black",
  "skin_color": "light",
  "eye_color": "brown",
  "birth_year": "24BBY",
  "gender": "male",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/1/"
  ],
  "species": [],
  "vehicles": [],
  "starships": [
    "https://swapi.dev/api/starships/12/"
  ],
  "created": "2014-12-10T15:59:50.509000Z",
  "edited": "2014-12-20T21:17:50.323000Z",
  "url": "https://swapi.dev/api/people/9/"
}
{
  "name": "Obi-Wan Kenobi",
  "height": "182",
  "mass": "77",
  "hair_color": "auburn, white",
  "skin_color": "fair",
  "eye_color": "blue-gray",
  "birth_year": "57BBY",
  "gender": "male",
  "homeworld": "https://swapi.dev/api/planets/20/",
  "films": [
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/4/",
    "https://swapi.dev/api/films/5/",
    "https://swapi.dev/api/films/6/"
  ],
  "species": [],
  "vehicles": [
    "https://swapi.dev/api/vehicles/38/"
  ],
  "starships": [
    "https://swapi.dev/api/starships/48/",
    "https://swapi.dev/api/starships/59/",
    "https://swapi.dev/api/starships/64/",
    "https://swapi.dev/api/starships/65/",
    "https://swapi.dev/api/starships/74/"
  ],
  "created": "2014-12-10T16:16:29.192000Z",
  "edited": "2014-12-20T21:17:50.325000Z",
  "url": "https://swapi.dev/api/people/10/"
}

配列内の特定の要素を取得する場合は'.配列名[].特定の要素名'で取得できます。

cat people.json | jq '.results[].name'

実行結果

"Luke Skywalker"
"C-3PO"
"R2-D2"
"Darth Vader"
"Leia Organa"
"Owen Lars"
"Beru Whitesun lars"
"R5-D4"
"Biggs Darklighter"
"Obi-Wan Kenobi"

-rオプションでダブルクォートを取り除いて無しの形で出力できます。

cat people.json | jq -r '.results[].name'

実行結果

Luke Skywalker
C-3PO
R2-D2
Darth Vader
Leia Organa
Owen Lars
Beru Whitesun lars
R5-D4
Biggs Darklighter
Obi-Wan Kenobi

配列内の特定の要素を要素番号を指定して取得する場合は'.配列名[要素番号].特定の要素名'で取得できます。

cat people.json | jq '.results[2].name'

実行結果

"R2-D2"

要素番号は以下のように範囲指定ができます。この場合、0以上3未満の要素を指定しています。

cat people.json | jq '.results[0:3]'

実行結果

[
  {
    "name": "Luke Skywalker",
    "height": "172",
    "mass": "77",
    "hair_color": "blond",
    "skin_color": "fair",
    "eye_color": "blue",
    "birth_year": "19BBY",
    "gender": "male",
    "homeworld": "https://swapi.dev/api/planets/1/",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/6/"
    ],
    "species": [],
    "vehicles": [
      "https://swapi.dev/api/vehicles/14/",
      "https://swapi.dev/api/vehicles/30/"
    ],
    "starships": [
      "https://swapi.dev/api/starships/12/",
      "https://swapi.dev/api/starships/22/"
    ],
    "created": "2014-12-09T13:50:51.644000Z",
    "edited": "2014-12-20T21:17:56.891000Z",
    "url": "https://swapi.dev/api/people/1/"
  },
  {
    "name": "C-3PO",
    "height": "167",
    "mass": "75",
    "hair_color": "n/a",
    "skin_color": "gold",
    "eye_color": "yellow",
    "birth_year": "112BBY",
    "gender": "n/a",
    "homeworld": "https://swapi.dev/api/planets/1/",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/4/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ],
    "species": [
      "https://swapi.dev/api/species/2/"
    ],
    "vehicles": [],
    "starships": [],
    "created": "2014-12-10T15:10:51.357000Z",
    "edited": "2014-12-20T21:17:50.309000Z",
    "url": "https://swapi.dev/api/people/2/"
  },
  {
    "name": "R2-D2",
    "height": "96",
    "mass": "32",
    "hair_color": "n/a",
    "skin_color": "white, blue",
    "eye_color": "red",
    "birth_year": "33BBY",
    "gender": "n/a",
    "homeworld": "https://swapi.dev/api/planets/8/",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/4/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ],
    "species": [
      "https://swapi.dev/api/species/2/"
    ],
    "vehicles": [],
    "starships": [],
    "created": "2014-12-10T15:11:50.376000Z",
    "edited": "2014-12-20T21:17:50.311000Z",
    "url": "https://swapi.dev/api/people/3/"
  }
]

2-3 要素数を取得

lengthでJSONデータの要素数を取得できます。

cat people.json | jq '. | length'

実行結果

4

特定の配列の要素数も取得できます。

cat people.json | jq '[.results[]] | length'

実行結果

10

2-4 新しい配列を作成

mapを使うと新しい配列を作成できます。

cat people.json |  jq  -r '.results | map( .name)'

実行結果

[
  "Luke Skywalker",
  "C-3PO",
  "R2-D2",
  "Darth Vader",
  "Leia Organa",
  "Owen Lars",
  "Beru Whitesun lars",
  "R5-D4",
  "Biggs Darklighter",
  "Obi-Wan Kenobi"
]

cat people.json |  jq  -r '.results | map({ name: .name, films: .films})'

実行結果

[
  {
    "name": "Luke Skywalker",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "C-3PO",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/4/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "R2-D2",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/4/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "Darth Vader",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "Leia Organa",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "Owen Lars",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "Beru Whitesun lars",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ]
  },
  {
    "name": "R5-D4",
    "films": [
      "https://swapi.dev/api/films/1/"
    ]
  },
  {
    "name": "Biggs Darklighter",
    "films": [
      "https://swapi.dev/api/films/1/"
    ]
  },
  {
    "name": "Obi-Wan Kenobi",
    "films": [
      "https://swapi.dev/api/films/1/",
      "https://swapi.dev/api/films/2/",
      "https://swapi.dev/api/films/3/",
      "https://swapi.dev/api/films/4/",
      "https://swapi.dev/api/films/5/",
      "https://swapi.dev/api/films/6/"
    ]
  }
]

2-5 一意の要素の取り出し

配列から一意の要素を取り出します。
まず、results.vehiclesの値を取り出して配列を生成します。

cat people.json |  jq  -r '.results | map( .vehicles[])'

実行結果

[
  "https://swapi.dev/api/vehicles/14/",
  "https://swapi.dev/api/vehicles/30/",
  "https://swapi.dev/api/vehicles/30/",
  "https://swapi.dev/api/vehicles/38/"
]

👆の配列に対してuniqueをパイプで繋げると配列内の一意の値が取得できます。

cat people.json |  jq  -r '.results | map( .vehicles[]) | unique'

実行結果

[
  "https://swapi.dev/api/vehicles/14/",
  "https://swapi.dev/api/vehicles/30/",
  "https://swapi.dev/api/vehicles/38/"
]

2-6 要素の絞り込み

select(boolean_expression)で絞り込みが可能です。以下の例では、results.genderがmaleのものに絞り込んで、nameを出力しています。

cat people.json | jq '.results[] | select( .gender == "male") | .name'

実行結果

"Luke Skywalker"
"Darth Vader"
"Owen Lars"
"Biggs Darklighter"
"Obi-Wan Kenobi"

2-7 grepコマンドと組み合わせて絞り込む

続いてgrepコマンドを用いた絞り込みの例です。Star WarsAPIのJSONデータだとあまり良い例が思い浮かばなかったので、こちらのサンプルデータを使います。

files.json

{
  "files": [
    "test.js-xxxx.js",
    "test.js",
    "test.js-xxxx.js",
    "test.css",
    "test2.js"
  ]
}

grep -v "xxxx"などを使えば、ファイル名に"xxxx”を含まないファイルのみを抽出できます。

cat files.json | jq '.files[]' | grep -v "xxxx"

実行結果

"test.js"
"test.css"
"test2.js"

3 最後に

jqコマンドを知っていると、いざ必要な場面に活用できそうですね。個人的には、ファイルpathの絞り込みやカウントが必要な場面でかなり役に立ちました。他のコマンドと組み合わせてもいろいろなことができそうです！

4 参考

https://stedolan.github.io/jq/manual/

https://qiita.com/takeshinoda@github/items/2dec7a72930ec1f658af