CSV を変換する例。以下のように実行する。 ruby convert.rb blog.csv > convert.csv

convert.rb

# coding: UTF-8

require "csv"

options = {:headers => true,
           :return_headers => true, :write_headers => true}
delete_columns = %w{Path FileName}

CSV.filter(options) do |row|
  if row.header_row?
    row << "FilePath"
    delete_columns.each do |column|
      row.delete(column)
    end
    next
  end

  row["Text"] << "ああ\nええ"
  
  filePath = row["Path"]+"/"+row["FileName"]
  row["FilePath"] = filePath
  
  delete_columns.each do |column|
    row.delete(column)
  end
end