code: public static final function getRelativePath($absolutePath)
      {
          if (!is_string($absolutePath)) {
              throw new InvalidPathException();
          }
  
          $pattern = array(self::getRootPath(), DIRECTORY_SEPARATOR, '//');
          $replacement = array('', '/', '/');
  
          $raltivePath = str_replace($pattern, $replacement, $absolutePath);
  
          if(substr($raltivePath, 0, 1) != '/') {
              $raltivePath = '/' . $raltivePath;
          }
          
          return str_replace('/public', '', $raltivePath);
      }
docs: Returns relative path of the absolute path. When you pass $absolutePath='/var/www/vegas/config'  then the result
  should be '/config'
  
  @param string $absolutePath
  @throws InvalidPathException
  @return mixed|string