$re = '/(\d+:\d+:\d+\.\d+)\s+(\S+):\s+(\d+:\d+:\d+\.\d+)\s+op:\s+(\S+)\s+lun:\s+(\/\S+\/\S+)\s+lba:\s+(\d+)\s+0x[0-9A-F]+\s+xfer:\s+(\d+)\s+errno:\s+EIO:\s+\'I/O error\'$/';
$str = '12:57:57.092 localhost-3: 12:57:57.049 op: write lun: /dev/sdd lba: 15229894656 0x38BC5C000 xfer: 8192 errno: EIO: \'I/O error\'';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
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