我正在尝试使用preg\\u replace从RSS提要中删除6行内容。我已经在线测试了regex，它似乎选择了正确的行。不知何故，这些行没有被删除

add_action(\'the_content_feed\', \'remove_rss_links\');
    function remove_rss_links($content) {
    return preg_replace(".*appeared first on.*$", "", $content);
}

<category><![CDATA[General]]></category>

        <guid isPermaLink="false">http://heronsglengolf.com/?p=38</guid>
                <description><![CDATA[<p>Below is the directive the committee gave to our architect (Ron Garl) relative to tee renovation: Number “6” tees Must be an option for all holes New “6” tee construction on holes: 1,4,6,8,9, and &#8230; <a class="more-link" href="http://heronsglengolf.com/tees/">Continue reading <span class="meta-nav">&#8594;</span></a></p>
<p>The post <a rel="nofollow" href="http://foobar.com/tees/">Tees</a> appeared first on <a rel="nofollow" href="http://foobar.com">Golf Course Renovation</a>.</p>
]]></description>
                                <content:encoded><![CDATA[<p>The post <a rel="nofollow" href="http://foobar.com/tees/">Tees</a> appeared first on <a rel="nofollow" href="http://foobar.com">Golf Course Renovation</a>.</p>
]]></content:encoded>