Shell jq 命令行的常用方法

• 将 JSON 转为 key=value&key2=value2

  {
    "aaa": "v1",
    "bbb": "v2",
    "ccc": "v3"
  }

  aaa=v1&bbb=v2&ccc=v3

  echo '{"aaa": "v1", "bbb": "v2", "ccc": "v3"}' | jq -r 'to_entries | map("\(.key)=\(.value)") | join("&")'

• 处理编码

  echo '{"aaa": "v1", "bbb": false, "ccc": null}' | jq -r 'to_entries | map("\(.key)=\(.value // "")") | join("&")'

  aaa=hello%20world&bbb=a%26b%3Dc```

• 去除参数值为空的键名

  echo '{"aaa": "v1", "bbb": "v2", "ccc": ""}' | jq 'with_entries(select(.value != ""))'

  {
    "aaa": "v1",
    "bbb": "v2"
  }

• 提取多个字段

  [
    { "id": 1, "name": "project1", "description": "This is project 1", "created_at": "2023-01-01" },
    { "id": 2, "name": "project2", "description": "This is project 2", "created_at": "2023-02-01" },
    { "id": 3, "name": "project3", "description": "This is project 3", "created_at": "2023-03-01" }
  ]

  echo '[{"id":1,"name":"project1","description":"This is project 1","created_at":"2023-01-01"},{"id":2,"name":"project2","description":"This is project 2","created_at":"2023-02-01"},{"id":3,"name":"project3","description":"This is project 3","created_at":"2023-03-01"}]' | jq -r '.[] | (.id, .name)'

  1
  project1
  2
  project2
  3
  project3

• 提取多个字段,分组

  echo '[{"id":1,"name":"project1","description":"This is project 1","created_at":"2023-01-01"},{"id":2,"name":"project2","description":"This is project 2","created_at":"2023-02-01"},{"id":3,"name":"project3","description":"This is project 3","created_at":"2023-03-01"}]' | jq '.[] | {id, name}'

  {
    "id": 1,
    "name": "project1"
  }
  {
    "id": 2,
    "name": "project2"
  }
  {
    "id": 3,
    "name": "project3"
  }

• 插入文字
  如果是数组

  [{"name": "Alice"}, {"name": "Bob"}, {"name": "Charlie"}]

  jq '"数量有 " + (length|tostring) + " 个"' data.json

  如果是对象

  {"name": "Alice"}, {"name": "Bob"}, {"name": "Charlie"}

  jq '"对象中有 " + (keys | length | tostring) + " 个键"' data.json