bash Grep：无效的重复计数
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Grep: invalid repetition count
提问by jdotjdot
I'm very experienced with regex, but cannot figure out why this isn't working.
我对正则表达式非常有经验，但无法弄清楚为什么这不起作用。
My sample text:
我的示例文本：
{
"coord":
{
"lon":-74.01,
"lat":40.71
},
"sys":
{
"message":0.2452,
"country":"United States of America",
"sunrise":1394191161,
"sunset":1394232864
},
"weather":
[
{
"id":803,
"main":"Clouds",
"description":"broken clouds",
"icon":"04n"
}
],
"base":"cmc stations",
"main":
{
"temp":270.54,
"pressure":1035,
"humidity":53,
"temp_min":270.15,
"temp_max":271.15},
"wind":
{
"speed":2.1,
"deg":130},
"clouds":
{
"all":75
},
"dt":1394149980,
"id":5128581,
"name":"New York",
"cod":200
}
}
}
I'm trying to grab weather[0].id.
我试图抓住weather[0].id.
My full script (the curlgets the JSON):
我的完整脚本（curl获取 JSON）：
curl -s "http://api.openweathermap.org/data/2.5/weather?q=NYC,NY" 2>/dev/null | grep -e '"weather":.*?\[.*?\{.*?"id": ?\d{1,3}'
I always get the error
我总是收到错误
grep: invalid repetition count(s)
回答by John1024
grep -edoes not recognize \das digits. It does not recognize non-greedy forms like .*?. For the grepportion of your command, try:
grep -e不能识别\d为数字。它不能识别像.*?. 对于grep您的命令部分，请尝试：
grep -e '"weather":[^[]*\[[^{]*{[^}]*"id": *[0-9]\{1,3\}'
Alternatively, it your grepsupports it (GNU), use the -Poption for perl-like regex and your original regex will work:
或者，如果您grep支持它（GNU），请使用-P类似 perl 的正则表达式选项，您的原始正则表达式将起作用：
grep -P '"weather":.*?\[.*?\{.*?"id": ?\d{1,3}'
