Inside the file "http://tech2.bumbung.net/questions/words.txt" is a list of words that we would like to test whether each word is a palindrome.

palindrome.rb

# I/O file location
file_path = "/home/emu/RubyProjects/Bumbung/words.txt"  # words.txt file downloaded from the question link
output_path = "/home/emu/RubyProjects/Bumbung/palindrome.txt"

# read words from file
File.open(file_path, "r") do |f|
  f.each_line do |line|
    # remove punctuations from word, then downcase word to ignore case
    str = line.gsub(/[^a-zA-Z0-9\-]/,"").downcase

    # if original downcase string and reversed string are same
    # then its a palindrome, otherwise not
    # write output on the file (create output file if not exists)
    if(str == str.reverse)
      File.open(output_path, 'a') {|f| f.write("palindrome\n") }
    else
      File.open(output_path, 'a') {|f| f.write("not_palindrome\n") }
    end
  end
end