public function rel($source)
    {
        $fullpath = (string)$this->get($source);
        return FS::getRelative($fullpath, $this->root, '/');
    }
public function rel($source)
    {
        $fullpath = (string)$this->get($source);
        return FS::getRelative($fullpath, $this->root, '/');
    }
public function rel ( $ source ) { $ fullpath = ( string ) $ this -> get ( $ source ) ; return FS :: getRelative ( $ fullpath , $ this -> root , '/' ) ; }
Get relative path to file or directory

@param string $source (example: "default:file.txt")
@return null|string
Get relative path to file or directory