我试图解析从curl请求返回的JSON,就像这样:
curl 'http://twitter.com/users/username.json' |
sed -e 's/[{}]/''/g' |
awk -v k="text" '{n=split($0,a,","); for (i=1; i<=n; i++) print a[i]}'
上面将JSON划分为多个字段,例如:
% ...
"geo_enabled":false
"friends_count":245
"profile_text_color":"000000"
"status":"in_reply_to_screen_name":null
"source":"web"
"truncated":false
"text":"My status"
"favorited":false
% ...
我如何打印一个特定的字段(由-v k=文本表示)?
使用node . js
如果系统安装了Node.js,则可以在JSON中使用-p print和-e evaluate脚本标志。解析以提取所需的任何值。
一个简单的例子,使用JSON字符串{"foo": "bar"}并取出"foo"的值:
node -pe 'JSON.parse(process.argv[1]).foo' '{ "foo": "bar" }'
输出:
bar
因为我们可以访问cat和其他实用程序,我们可以对文件使用这个:
node -pe 'JSON.parse(process.argv[1]).foo' "$(cat foobar.json)"
输出:
bar
或包含JSON的URL等任何其他格式:
node -pe 'JSON.parse(process.argv[1]).name' "$(curl -s https://api.github.com/users/trevorsenior)"
输出:
Trevor Senior
还有一个非常简单但功能强大的JSON CLI处理工具fx。
例子
使用匿名函数:
echo '{"key": "value"}' | fx "x => x.key"
输出:
value
如果你不传递匿名函数参数→…,代码将自动转换为匿名函数。你可以通过这个关键字访问JSON:
$ echo '[1,2,3]' | fx "this.map(x => x * 2)"
[2, 4, 6]
或者也可以使用点语法:
echo '{"items": {"one": 1}}' | fx .items.one
输出:
1
你可以传递任意数量的匿名函数来减少JSON:
echo '{"items": ["one", "two"]}' | fx "this.items" "this[1]"
输出:
two
您可以使用扩展操作符更新现有JSON:
echo '{"count": 0}' | fx "{...this, count: 1}"
输出:
{"count": 1}
只是简单的JavaScript。没有必要学习新的语法。
fx的后期版本有一个互动模式!-
对于更复杂的JSON解析,我建议使用Python jsonpath模块(Stefan Goessner) -
Install it -
sudo easy_install -U jsonpath
Use it -
Example file.json (from http://goessner.net/articles/JsonPath) -
{ "store": {
"book": [
{ "category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": 8.95
},
{ "category": "fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": 12.99
},
{ "category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": 8.99
},
{ "category": "fiction",
"author": "J. R. R. Tolkien",
"title": "The Lord of the Rings",
"isbn": "0-395-19395-8",
"price": 22.99
}
],
"bicycle": {
"color": "red",
"price": 19.95
}
}
}
Parse it (extract all book titles with price < 10) -
cat file.json | python -c "import sys, json, jsonpath; print '\n'.join(jsonpath.jsonpath(json.load(sys.stdin), 'store.book[?(@.price < 10)].title'))"
Will output -
Sayings of the Century
Moby Dick
Note: The above command line does not include error checking. For a full solution with error checking, you should create a small Python script, and wrap the code with try-except.