$link = 'https://example.com/iCXjXu8/复制此链接，打开Dou音搜索，直接观看视频！';

$pattern = '/^(https?:\/\/[a-zA-Z0-9.-]+\/\w+)/';
preg_match($pattern, $link, $matches);

if(isset($matches[1])) {
    $result = $matches[1];
    echo $result;
} else {
    echo "无法提取链接地址";
}