code: function erase(num) {
    var n = typeof num === 'number' ? num : 1;
    return through.obj(function(file, enc, next) {
      var lines = file.contents.toString().trim().split('\n');
      file.contents = new Buffer(lines.slice(0, -n).join('\n') + '\n');
      next(null, file);
    });
  }
docs: Erase the given number of lines from the end of a string
  
  @param {String} `str`
  @return {Stream} vinyl stream
  @api public