function open_(cmd, path, successCallback) {
    if (!fs_) {
      return;
    }

    cwd_.getFile(path, {}, successCallback, function(e) {
      if (e.code == FileError.NOT_FOUND_ERR) {
        output(cmd + ': ' + path + ': No such file or directory<br>');
      }
    });
  }
Gets a reference to a file

@param {String} cmd The attempted command
@param {String} path The file path
@param {Function} successCallback Callback to pass the file reference