formatAll(results, options, showName) {
    let stdout = '';
    if (showName) {
      for (let i = 0; i < results.length; ++i) {
        stdout += `${results[i].path}:\n`;
        if (options.l) {
          stdout += `total ${results[i].size}\n`;
        }
        stdout += results[i].results;
        if (i !== results.length - 1) {
          stdout += '\n\n';
        }
      }
    } else if (results.length === 1) {
      if (options.l && !options.x) {
        stdout += `total ${results[0].size}\n`;
      }
      stdout += results[0].results;
    }
    return stdout;
  }
Concatenates the results of multiple
`execDir` functions into their proper
form based on options provided.

@param {Array} results
@param {Object} options
@param {boolean} showName
@return {String} stdout
@api private