reduce-amazon-url.rb

#!/bin/ruby
#
# Amazon の URL から冗長な要素を削除する.
#
# Example:
#     cat amazon-urls.txt | ruby reduce-amazon-url.rb
#

while line = gets do
    url = line.chomp
    if url =~ /\/dp\/([a-zA-Z0-9]+)/
        puts "https://www.amazon.co.jp/dp/#{$1}"
    else
        puts url
    end
end