code/Debug/Model/Logging.php
public function getContent($filePath, $startPosition, $endPosition)
    {
        if (!file_exists($filePath)) {
            return '';
        }

        // End position not saved yet
        if (!$endPosition) {
            return trim(file_get_contents($filePath, null, null, $startPosition));
        }

        // End position exists but is less then start position
        if ($endPosition <= $startPosition) {
            return '';
        }

        return trim(file_get_contents($filePath, null, null, $startPosition, $endPosition - $startPosition));
    }
public function getContent($filePath, $startPosition, $endPosition)
    {
        if (!file_exists($filePath)) {
            return '';
        }

        // End position not saved yet
        if (!$endPosition) {
            return trim(file_get_contents($filePath, null, null, $startPosition));
        }

        // End position exists but is less then start position
        if ($endPosition <= $startPosition) {
            return '';
        }

        return trim(file_get_contents($filePath, null, null, $startPosition, $endPosition - $startPosition));
    }
Returns content from specified file between specified range

@param string $filePath
@param int $startPosition
@param int $endPosition
@return string