linux工具之jq

简介

在linux下进行日常的开发时，我们经常需要对json格式的数据进行处理分析。

jq

是一个开源的JSON格式数据处理工具，它提供了很多灵活的语法，功能非常强大。

安装

• macOS:

brew install jq           

• Ubuntu

apt-get install jq           

• 其他参考 官网

jq语法

基础用法

假设文本test_json中有如下字符串

{
    "name":"xiaoming",
    "age":21,
    "birthday":"10th August",
    "email":"[email protected]",
    "skills":[
        {
            "name":"C++",
            "level":2
        },
        {
            "name":"Python",
            "level":1
        }
    ]
}           

通过key筛选

jq 表达式

cat test_json | jq ".name"           

输出

"xiaoming"           

通过index筛选

cat test_json | jq ".skills[0]"           

{
  "name": "C++",
  "level": 2
}           

遍历数组

jq表达式

cat test_json | jq ".skills[]"           

{
  "name": "C++",
  "level": 2
}
{
  "name": "Python",
  "level": 1
}           

通过Pipe（"|"）筛选

cat test_json | jq ".skills[] | .level"           

2
1           

构造数组Array

cat test_json | jq "[.age, .email]"           

[
  21,
  "[email protected]"
]           

构造Mapping

cat test_json | jq "{name, skills_2 : .skills}"           

{
  "name": "xiaoming",
  "skills_2": [
    {
      "name": "C++",
      "level": 2
    },
    {
      "name": "Python",
      "level": 1
    }
  ]
}           

cat test_json | jq "{(.name): .skills}"           

{
  "xiaoming": [
    {
      "name": "C++",
      "level": 2
    },
    {
      "name": "Python",
      "level": 1
    }
  ]
}           

内建操作符和函数

加法

cat test_json | jq ".age + 1"           

22           

字符拼接

cat test_json | jq ".age + .name"           

"[email protected]"           

减法 -

echo '["xml", "yaml", "json"]' | jq '. - ["xml", "yaml"]'           

[
  "json"
]           

Length

echo '[[1,2], "string", {"a":2}, null]' | jq '[.[]| length]'           

[
  2,
  6,
  1,
  0
]           

keys

cat test_json | jq 'keys'           

[
  "age",
  "birthday",
  "email",
  "name",
  "skills"
]           

in

echo '["foo", "bar"]' | jq '.[] | in({"foo": 42})'           

true
false           

map

echo '[1,2,3]' | jq 'map(.+1)'           

[
  2,
  3,
  4
]           

map_values

echo '{"a": 1, "b": 2, "c": 3}' | jq 'map_values(.+1)'           

{
  "a": 2,
  "b": 3,
  "c": 4
}           

del

js表达式

echo '{"foo": 42, "bar": 9001, "baz": 42}' | jq "del(.foo)"           

{
  "bar": 9001,
  "baz": 42
}           

select

echo '[{"id": "first", "val": 1}, {"id": "second", "val": 2}]' | jq '.[] | select(.id == "second")'           

{
  "id": "second",
  "val": 2
}           

any

echo '[true, false]' | jq 'any'           

true           

all

echo '[true, false]' | jq 'all'           

false           

min、max

echo '[5,4,2,7]' | jq 'min'           

2           

sort、sort_by

echo '[8,3,null,6]' | jq 'sort'           

[
  null,
  3,
  6,
  8
]           

echo '[{"foo":4, "bar":10}, {"foo":3, "bar":100}, {"foo":2, "bar":1}]' | jq 'sort_by(.foo)'           

[
  {
    "foo": 2,
    "bar": 1
  },
  {
    "foo": 3,
    "bar": 100
  },
  {
    "foo": 4,
    "bar": 10
  }
]           

index

echo '["a","b", "c"]' | jq 'index("b")'           

1           

json

echo '["a","b","c"]' | jq 'join(";")'           

"a;b;c"           

条件判断

echo 2 | jq 'if . == 0 then  "zero" elif . == 1 then "one" else  "many" end'           

"many"           

参考

• 官方参考文档