docs: function ps(filterer) {
    let processes = null;
  
    if (isPlatform('osx')) {
      processes = _osxPs();
    } else {
      processes = _procfsPs();
    }
  
    if (!filterer) {
      return processes;
    } else if (_.isFunction(filterer) || _.isReallyObject(filterer)) {
      return _.filter(processes, filterer);
    } else if (_.isNumber(filterer) || _.isString(filterer) && _.isFinite(parseInt(filterer, 10))) {
      return _.find(processes, {pid: parseInt(filterer, 10)}) || null;
    } else {
      throw new Error('Don\'t know how to handle filterer');
    }
  }