linux 下jq的使用

本文主要是介绍linux 下jq的使用，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

安装：
yum install jq -y
文档：
https://stedolan.github.io/jq/manual/

数据源
333.json

[{
    "name": "站长工具",
    "url": "http://tool.chinaz.com",
    "address": {
      "city": "厦门",
      "country": "中国"
    },
    "arrayBrowser": [{
        "name": "Google",
        "url": "http://www.google.com"
      },
      {
        "name": "Baidu",
        "url": "http://www.baidu.com"
      }
    ]
  },
  {
    "name": "站长之家",
    "url": "http://tool.zzhome.com",
    "address": {
      "city": "大连",
      "country": "中国"
    },
    "arrayBrowser": [{
        "name": "360",
        "url": "http://www.so.com"
      },
      {
        "name": "bing",
        "url": "http://www.bing.com"
      }
    ],
    "127.0.0.1": {
      "error": 200,
      "msg": "ok"
    }
  }
]

例子基础

haima@haima-PC:~/Desktop$ cat 333.json |jq '.'
[
  {
    "name": "站长工具",
    "url": "http://tool.chinaz.com",
    "address": {
      "city": "厦门",
      "country": "中国"
    },
    "arrayBrowser": [
      {
        "name": "Google",
        "url": "http://www.google.com"
      },
      {
        "name": "Baidu",
        "url": "http://www.baidu.com"
      }
    ]
  },
  {
    "name": "站长之家",
    "url": "http://tool.zzhome.com",
    "address": {
      "city": "大连",
      "country": "中国"
    },
    "arrayBrowser": [
      {
        "name": "360",
        "url": "http://www.so.com"
      },
      {
        "name": "bing",
        "url": "http://www.bing.com"
      }
    ],
    "127.0.0.1": {
      "error": 200,
      "msg": "ok"
    }
  }
]

管道线 |
jq支持管道线 |，它如同linux命令中的管道线——把前面命令的输出当作是后面命令的输入。如下命令把.[0]作为{…}的输入，进而访问嵌套的属性，如.name和.address.city。
观察如下几个命令，通过改变|前后的输入和输出来达到不同的效果：

cat json.txt | jq '.[0] | {name:.name,city:.address.city}'

{
  "name": "站长工具",
  "city": "厦门"
}

cat json.txt | jq '.[0] | {name:.arrayBrowser[1].name,city:.address.city}'

{
  "name": "Baidu",
  "city": "厦门"
}

cat json.txt | jq ".[] | {name:.arrayBrowser[1].name,city:.address.city}"

{
  "name": "Baidu",
  "city": "厦门"
}
{
  "name": "bing",
  "city": "大连"
}

[]
如果希望把jq的输出当作一个数组，可以在前后加上[]：

cat json.txt | jq "[.[] | {name:.arrayBrowser[1].name,city:.address.city}]"
[
  {
    "name": "Baidu",
    "city": "厦门"
  },
  {
    "name": "bing",
    "city": "大连"
  }
]

自定义key
在{}中，冒号前面的名字是映射的名称，你可以任意修改，如：

```sh
cat json.txt | jq "[.[] | {name_001:.arrayBrowser[1].name,city_002:.address.city}]"

[
  {
    "name_001": "Baidu",
    "city_002": "厦门"
  },
  {
    "name_001": "bing",
    "city_002": "大连"
  }
]

原文链接：https://blog.csdn.net/qq_26502245/article/details/100191694

取0号单元下的元素

haima@haima-PC:~/Desktop$ cat 333.json |jq '.[0].name'
"站长工具"
haima@haima-PC:~/Desktop$ cat 333.json |jq '.[0].address'
{
  "city": "厦门",
  "country": "中国"
}
haima@haima-PC:~/Desktop$ cat 333.json |jq '.[0].address.city'
"厦门"
haima@haima-PC:~/Desktop$ cat 333.json |jq '.[0].address["city"]'
"厦门"
haima@haima-PC:~/Desktop$ cat 333.json |jq ".[0].address[\"city\"]"
"厦门"
haima@haima-PC:~/Desktop$ cat 333.json |jq '.[1]["127.0.0.1"]'
{
  "error": 200,
  "msg": "ok"
}
haima@haima-PC:~/Desktop$ cat 333.json | jq ".[0]" | jq 'keys' #获取0号单元的所有key
[
  "address",
  "arrayBrowser",
  "name",
  "url"
]
haima@haima-PC:~/Desktop$ cat 333.json | jq ".[0].address" # 获取0号单元的address
{
  "city": "厦门",
  "country": "中国"
}
haima@haima-PC:~/Desktop$ cat 333.json | jq ".[0].address" | jq 'keys' #获取0号单元的address里的所有 key(嵌套提取)
[
  "city",
  "country"
]
haima@haima-PC:~/Desktop$ cat 333.json | jq ".[0]" | jq 'has("name")' #判断是否有某个 key
true
haima@haima-PC:~/Desktop$ cat 333.json | jq ".[0]" | jq 'has("test")' #判断是否有某个 key
false

压缩json

haima@haima-PC:~/Desktop$ cat 333.json | jq -c . 
[{"name":"站长工具","url":"http://tool.chinaz.com","address":{"city":"厦门","country":"中国"},"arrayBrowser":[{"name":"Google","url":"http://www.google.com"},{"name":"Baidu","url":"http://www.baidu.com"}]},{"name":"站长之家","url":"http://tool.zzhome.com","address":{"city":"大连","country":"中国"},"arrayBrowser":[{"name":"360","url":"http://www.so.com"},{"name":"bing","url":"http://www.bing.com"}],"127.0.0.1":{"error":200,"msg":"ok"}}]

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