archivo de registro de apache de preg coincidente
$regex = '/^\[([^\]]+)\] \[([^\]]+)\] (?:\[client ([^\]]+)\])?\s*(.*)$/i';
preg_match($regex, $log, $matches);
$matches[1] = Date and time, $matches[2] = severity,
$matches[3] = client addr (if present) $matches[4] = log message
Matteoweb