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I don't know enough regex to know why it's not working, but it doesn't seem to be picking out that information.<br />
I've tried both in powershell and regextester.com
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Don't understand it works in regextester.com<br />
<br />
<a href="https://filedb.experts-exchange.com/incoming/2016/03_w12/1086771/Regex1.png" target="_blank" title="EE (255 KB)"><img alt="EE" class="file-block lazyload" style="max-width: 800px;" data-src="https://filedb.experts-exchange.com/incoming/2016/03_w12/800_1086771/Regex1.png" /></a><br />
how do you use it?
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Regex1.png

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I have these examples in regextester:<br />
<br />
abc-def.ghi.uk<br />
facebook.com<br />
somewhere.somewhereelse.co<wbr />m<br />
abcdefg.com<br />
abcdefg.cn<br />
abc.def.org<br />
<br />
<br />
Should it highlight just one, or any matches?<br />
I'll be pulling these from an array, if that matters?
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If I take off the trailing $, it matches the def.ghi portion of this, but I would need ghi.uk from it...doesn't match anything with the $ left on.<br />
<br />
abc-def.ghi.uk
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Weird - same regex and test as your screen shot, but it fails on mine with the exact same data?<br />
<br />
<a href="https://filedb.experts-exchange.com/incoming/2016/03_w12/1087019/regextest.png" target="_blank" title="regextest.png (57 KB)"><img alt="regextest.png" class="file-block lazyload" style="max-width: 643px;" data-src="https://filedb.experts-exchange.com/incoming/2016/03_w12/1087019/regextest.png" /></a>
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regextest.png

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Is there a space after org?
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Looking for a regex that will match the parent domain only.<br />
in examples like the following<br />
abcdefg.com &nbsp; = &nbsp;abcdefg.com<br />
abcdefg.cn &nbsp;= &nbsp; &nbsp; &nbsp;abcdefg.cn<br />
abc.def.org &nbsp; = &nbsp;def.org<br />
abc-def.ghi.uk &nbsp;= ghi.uk<br />
<br />
This is the output of a cmdlet that won't produce any <a href="http://" rel="ugc nofollow">http://</a>&nbsp;prefix, nor any trailing pages - just the domain info, but I only want to extract the parent. Thanks!
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Looking for a regex that will match the parent domain only.
in examples like the following
abcdefg.com   =  abcdefg.com
abcdefg.cn  =      abcdefg.cn
abc.def.org   =  def.org
abc-def.ghi.uk  = ghi.uk

This is the output of a cmdlet that won't produce any http:// prefix, nor any trailing pages - just the domain info, but I only want to extract the parent. Thanks!

regular expression - parent domain only

A regular expression ("regex") is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings, or string matching, i.e. "find and replace"-like operations. Regular expression processors are found in several search engines, search and replace dialogs of several word processors and text editors, and in the command lines of text processing utilities, such as sed and AWK. Many programming languages provide regular expression capabilities, some built-in, for example Perl, JavaScript, Ruby, AWK, and Tcl, and others via a standard library, for example .NET languages, Java, Python and C++ (since C++11). Most other languages offer regular expressions via a library.