如果您经常从命令行或shell脚本处理JSON格式的文本，你一定特别希望有一个Linux命令行下的JSON解析工具。

在本文中，将介绍一下Linux命令行下的JSON字符串的解析工具jq。

1、安装jq:

CentOS 系统的epel源提供了该软件包，可以直接使用yum安装：

$ yum -y install jq

2、JSON示例：

$ cat json.txt
{
        "name": "Google",
        "location":
                {
                        "street": "1600 Amphitheatre Parkway",
                        "city": "Mountain View",
                        "state": "California",
                        "country": "US"
                },
        "employees":
                [
                        {
                                "name": "Michael",
                                "division": "Engineering"
                        },
                        {
                                "name": "Laura",
                                "division": "HR"
                        },
                        {
                                "name": "Elise",
                                "division": "Marketing"
                        }
                ]
}

3、jq示例：

## 1. 格式化JSON：
$ cat json.txt | jq .
{
  "name": "Google",
  "location": {
    "street": "1600 Amphitheatre Parkway",
    "city": "Mountain View",
    "state": "California",
    "country": "US"
  },
  "employees": [
    {
      "name": "Michael",
      "division": "Engineering"
    },
    {
      "name": "Laura",
      "division": "HR"
    },
    {
      "name": "Elise",
      "division": "Marketing"
    }
  ]
}

## 2. 解析JSON对象：
$ cat json.txt | jq '.name'
"Google"

## 3. 解析嵌套的JSON对象：
$ cat json.txt | jq '.location.city'
"Mountain View"

## 4. 解析JSON数组：
$ cat json.txt | jq '.employees[0].name'
"Michael"

## 5. 从一个JSON对象中提取特定字段:
$ cat json.txt | jq '.location | {street, city}'
{
  "city": "Mountain View",
  "street": "1600 Amphitheatre Parkway"
}

## 6. JSON对象的过滤：
$ cat json.txt | jq '.employees|.[]|select(.name=="Elise")'
{
  "division": "Marketing",
  "name": "Elise"
}

## 7.JSON对象的多重过滤：
$ cat json.txt | jq '.employees|.[]|select(.name=="Elise")|.division'
"Marketing"

参考资料：

• How to parse JSON string via command line on Linux