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allada01
Asked: 2020-07-17 03:46:20 +0800 CST

如何在命令行中 grep JSON 键的值？

  • 772

这是我的这个命令的 JSON 输出，aws logs list-log-groups我需要从这里获取第一个“arn”值。我怎样才能做到这一点？

{
    "logGroups": [
        {
            "logGroupName": "alla",
            "creationTime": 1594638588652,
            "metricFilterCount": 0,
            "arn": "arn:aws:logs:us-east-1:12345678910:log-group:*:*",
            "storedBytes": 0
        },
        {
            "logGroupName": "mahi",
            "creationTime": 1594638580461,
            "metricFilterCount": 0,
            "arn": "arn:aws:logs:us-east-1:12345678910:log-group:*:*",
            "storedBytes": 0
        }
    ]
}
command-line aws text-processing

2 个回答

  1. 使用jq：

    aws logs list-log-groups | jq -r '.logGroups[0].arn'

    输出：

    arn:aws:logs:us-east-1:929815623526:log-group:alla:

    jq可以从universe存储库安装：

    sudo apt install jq

    jq是解析的首选json，但如果jq由于某种原因没有选项并且您知道格式不会改变，您可以使用grep -Pand head -n1：

    aws logs list-log-groups | grep -Po '"arn": "\K[^"]*' | head -n1
    • 2
  2. Best Answer

    我最近发现了一个名为gron.

    gron <<'END_JSON'
{
    "logGroups": [
        {
            "logGroupName": "alla",
            "creationTime": 1594638588652,
            "metricFilterCount": 0,
            "arn": "arn:aws:logs:us-east-1:12345678910:log-group:*:*",
            "storedBytes": 0
        },
        {
            "logGroupName": "mahi",
            "creationTime": 1594638580461,
            "metricFilterCount": 0,
            "arn": "arn:aws:logs:us-east-1:12345678910:log-group:*:*",
            "storedBytes": 0
        }
    ]
}
END_JSON

    json = {};
json.logGroups = [];
json.logGroups[0] = {};
json.logGroups[0].arn = "arn:aws:logs:us-east-1:12345678910:log-group:*:*";
json.logGroups[0].creationTime = 1594638588652;
json.logGroups[0].logGroupName = "alla";
json.logGroups[0].metricFilterCount = 0;
json.logGroups[0].storedBytes = 0;
json.logGroups[1] = {};
json.logGroups[1].arn = "arn:aws:logs:us-east-1:12345678910:log-group:*:*";
json.logGroups[1].creationTime = 1594638580461;
json.logGroups[1].logGroupName = "mahi";
json.logGroups[1].metricFilterCount = 0;
json.logGroups[1].storedBytes = 0;

    该工具将 JSON 表示法转换为易于 greppable 的逐行 javascript。

    $ arn=$(gron <<'END_JSON' | sed -En '/json\.logGroups\[0\]\.arn/ s/^[^"]*"(.*)";$/\1/p'
{
  ...
}
END_JSON
)
$ echo "$arn"
arn:aws:logs:us-east-1:12345678910:log-group:*:*
    • 2

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