$re = '/<span.*>(.*?)<\/span>/';
$str = '<!--WYSIWYG content - do not remove this comment, and never use this identical text in your topics-->
<p>-- <span class="WYSIWYG_LINK">Main.SeanOReilly</span> - 2017-08-30</p>
<h1 class="TML">Technology used</h1>
<p><span class="WYSIWYG_LINK">[[http://www.oracle.com/technetwork/developer-tools/rest-data-services/overview/index.html][ORDS (Oracle REST data services)]]</span></p>
<h1 class="TML"></h1>
<h1 class="TML">REST concepts</h1>
<table border="1" cellspacing="1" cellpadding="0">
<tbody>
<tr>
<td>GET</td>
<td class="align-left" style="text-align: left">select</td>
</tr>
<tr>
<td>POST</td>
<td class="align-left" style="text-align: left">insert</td>
</tr>
<tr>
<td>PUT</td>
<td class="align-left" style="text-align: left">update</td>
</tr>
<tr>
<td>DELETE</td>
<td class="align-left" style="text-align: left">delete</td>
</tr>
</tbody>
</table>
<h1 class="TML"></h1>
<h1 class="TML">Settings</h1>
<p><img title="ORDS_ords_admin.JPG" src="http://itwiki.core.kmtltd.net.au/pub/Main/SupplyChainIntl/RESTDataAPI/ORDS_ords_admin.JPG" alt="ORDS_ords_admin.JPG" width="356" height="281" /></p>
<p><img title="ORDS_ords_dev.JPG" src="http://itwiki.core.kmtltd.net.au/pub/Main/SupplyChainIntl/RESTDataAPI/ORDS_ords_dev.JPG" alt="ORDS_ords_dev.JPG" width="356" height="281" /></p>
<p><span class="WYSIWYG_LINK">[[http://www.oracle.com/technetwork/developer-tools/rest-data-services/learnmore/index.html]]</span></p>
<h1 class="TML">Kmart Developer website</h1>
<p><span class="WYSIWYG_LINK">[[https://developer.core.kmtltd.net.au/]]</span></p>
<h1 class="TML">Data dictionary</h1>
<p><span class="WYSIWYG_LINK">ProductNumber</span></p>
<p><span class="WYSIWYG_LINK">UnitQuantity</span></p>
<h1 class="TML">Development notes</h1>
<p>\\\\warthog\\grpdata\\Kmart IT Team\\4. Supply Chain & Finance Delivery\\1. GIF\\1. Apps & Systems\\5. Other\\Tasks\\170823 API</p>
<h1 class="TML">Examples</h1>
<h2 class="TML"><span class="WYSIWYG_LINK">AutoREST</span></h2>
<p><span class="WYSIWYG_LINK">http://kuttsi901:8080/ords/exuts/container/</span></p>
<h2 class="TML">Configured REST</h2>
<p><span class="WYSIWYG_LINK">http://kuttsi901:8080/ords/exuts//v1/container/MAEU8378519</span></p>';
$subst = "\1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php