从命令行参数生成JSON [英] generate JSON out of command line arguments

问题描述

我想用jq 创建JSON输出，如下所示:

I want to create JSON output with jq that looks like this:

{
  "records": [
    {
      "id": "1234",
      "song": "Yesterday",
      "artist": "The Beatles"
    }
  ]
}

我以为我不得不纠结jq的过滤器"，在阅读文档后，我对它的概念还不完全了解.

I assumed I have to twiddle with the "filter" of jq whose concept I don't fully get after reading the doc.

这是我到目前为止得到的:

This is what I got so far:

$ jq --arg id 1234 \
     --arg song Yesterday \
     --arg artist "The Beatles" \
  '.' \
  <<<'{ "records" : [{ "id":"$id", "song":"$song", "artist":"$artist" }] }'

可打印

{
  "records": [
    {
      "id" : "$id",
      "song" : "$song",
      "artist" : "$artist"
    }
  ]
}

我是否修改过滤器?我要更改输入吗?

Do I modify the filter? Do I change the input?

推荐答案

您正在寻找这样的东西:

You are looking for something like this:

jq --null-input               \
   --arg id 1234              \
   --arg song Yesterday       \
   --arg artist "The Beatles" \
'.records[0] = {$id, $song, $artist}'

大括号之间的每个变量引用都转换为一个键-值对，其名称是键，其值是值.并将结果对象分配给.records[0]会强制创建周围的结构.

Each variable reference between curly brackets is converted to a key-value pair where its name is the key, and its value is the value. And assigning the resulting object to .records[0] forces the creation of the surrounding structure.

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