shell 使用jq对json数据进行提取（shell获取json文件中的内容）

jq命令允许直接在命令行下对JSON进行操作, 包括分片、过滤、转换等, jq是用C编写, 没有运行时依赖, 所以几乎可以运行在任何系统上。

预编译的二进制文件可以直接在Linux、OS X和windows系统上运行, 当然在linux和OS X系统你需要赋与其可执行权限, 在linux系统中也可以直接用yum安装。

># yum install ja

下载地址:

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

现在先准备json串, 如下kumufengchun.json:

{"name":"kumufengchun","age":"18","city":"beijing","email":"kumufengchun@gmail.com","date":"Thursday","country":"China","company":["baidu","google","alibaba"]}"

test.json:

[{"name":"JSON", "good":true}, {"name":"XML", "good":false}]

1.用jq .直接查看

jq . kumufengchun.json

或者

cat kumufengchun.json | jq .

输出如下：

> # cat kumufengchun.json | jq .

{

"name": "kumufengchun",

"age": "18",

"city": "beijing",

"email": "kumufengchun@gmail.com",

"date": "Thursday",

"country": "China",

"company": [

"baidu",

"google",

"alibaba"

]

}

2.输出某个字段或者某个索引的值

语法：jq '.', 这里key是字段名称

> # jq .name kumufengchun.json

"kumufengchun"

> # jq '.name' kumufengchun.json

"kumufengchun"

> # jq '.company' kumufengchun.json

[

"baidu",

"google",

"alibaba"

]

3.输出数组的值

语法：jq '.[]', 这里value是数组的索引整数值

> # jq '.company[1]' kumufengchun.json

"google"

[root@localhost ~]$ jq '.company[2]' kumufengchun.json

"alibaba"

4.输出列表、数组的一部分, 对其进行切片

语法：jq '.[s:e]',返回的是数组或者列表的index从s开始(包括s)到e结束(不包括e)

> # jq '.company[0:2]' kumufengchun.json

[

"baidu",

"google"

]

也可以省略开始的index, 只有结束的index, 如下, 仍然是不包括结束index的值：

> # jq '.company[:3]' kumufengchun.json

[

"baidu",

"google",

"alibaba"

]

也可以省略结束的index, 只有开始的index, 如下, 输出到最后：

> # jq '.company[1:]' kumufengchun.json

[

"google",

"alibaba"

]

开始的索引也可以是负数, 表示从后边倒着数, 从-1开始数：

> # jq '.company[-2:]' kumufengchun.json

[

"google",

"alibaba"

]

5.循环输出所有的值, 如数组嵌套

语法：jq '.[]'

> # jq '.[]' test.json

{

"name": "JSON",

"good": true

}

{

"name": "XML",

"good": false

}

> # jq '.[]' kumufengchun.json

"kumufengchun"

"18"

"beijing"

"kumufengchun@gmail.com"

"Thursday"

"China"

[

"baidu",

"google",

"alibaba"

]

6.输出多个索引的值, 可以用逗号分割

语法： jq '.key1,.key2'

> # jq '.name,.age' kumufengchun.json

"kumufengchun"

"18"

> # jq '.date,.company[]' kumufengchun.json

"Thursday"

"baidu"

"google"

"alibaba"

如果是数组, 用中括号括起来要输出的键值, 键值先写谁, 先输出谁

> # jq '.company[2,0]' kumufengchun.json

"alibaba"

"baidu"

7.用管道符号｜可以对其进行再次处理

语法：jq .[] | .

> # jq '.[]|.name' test.json

"JSON"

"XML"

8.括号的作用

> # echo 1 | jq '(.+2)*5'

15

> # echo {1,2,3} | jq '(.+2)*5'

15

20

25

9.length求长度

如果是字符串是求的字符串的长度, 如果是数组则求得是数组的长度

> # cat kumufengchun.json | jq '.[] | length'

12

2

7

22

8

5

3

10.输出所有的keys

语法： jq keys

> # cat kumufengchun.json | jq 'keys'

[

"age",

"city",

"company",

"country",

"date",

"email",

"name"

]

输出数组的keys:

> # cat kumufengchun.json | jq '.company | keys'

[

0,

1,

2

]

11.判断存不存在某个键

> # cat kumufengchun.json | jq 'has("email")'

true

> # cat kumufengchun.json | jq 'has("address")'

false