在终端中使用RegEx从字符串中提取字符串
问题描述：
我有一个字符串，如first url, second url, third url，并且想在OS X终端中仅提取单词second之后的url(仅第一次出现).我该怎么办?
I have a string like first url, second url, third url and would like to extract only the url after the word second in the OS X Terminal (only the first occurrence). How can I do it?
在我最喜欢的编辑器中，我使用了正则表达式/second (url)/并使用了$1来提取它，我只是不知道如何在终端中进行操作.
In my favorite editor I used the regex /second (url)/ and used $1 to extract it, I just don't know how to do it in the Terminal.
请记住，url是实际的URL，我将使用以下表达式之一对其进行匹配:
Keep in mind that url is an actual url, I'll be using one of these expressions to match it: Regex to match URL
答
echo 'first url, second url, third url' | sed 's/.*second//'
我误会了.更好:
echo 'first url, second url, third url' | sed 's/.*second \([^ ]*\).*/\1/'
或:
echo 'first url, second url, third url' | perl -nle 'm/second ([^ ]*)/; print $1'