Find licenses of the gems you're using

gemlicenses.rb

#!/usr/bin/ruby

gem_root = '/Users/federico/.rvm/gems/ruby-1.8.7-p330@coderloop/gems'

Dir.open(gem_root) do |dir|
  gems = {}
  dir.each do |gemfolder| 
    gemname = gemfolder.match(/^.+-/)
    next if gemname.nil?
    gemname = gemname[0]
    if gems[gemname].nil? || gems[gemname][:folder] < gemfolder
      gems[gemname] = { :folder => gemfolder }
    end
  end
  
  gems.each do |gemname, data|
    Dir.open(File.join(gem_root, data[:folder])) do |gem_dir|
      gem_dir.each do |gem_file|
        if gem_file.match(/GPL|license|MIT|COPYING/i)
          data[:license_file] = gem_file
          next
        end 
      end
  
      unless data[:license_file]
        gem_dir.each do |gem_file|
          if gem_file.match(/readme/i)
            File.open(File.join(gem_root, data[:folder], gem_file)) do |file|
              content = file.read
              if content.match(/license/im)
                data[:license_file] = gem_file
              end
            end
          end
        end
      end
      
      next unless data[:license_file]

      File.open(File.join(gem_root, data[:folder], data[:license_file])) do |file|
        content = file.read.gsub(/\n/, ' ').gsub(/\s+/,' ')
        if content.match(/MIT\s+LICENSE|Permission is hereby granted, free of charge, to any person obtaining/im)
          data[:license] = 'MIT'
          next
        end
        if content.match(/GPL|GNU GENERAL PUBLIC LICENSE/im)
          data[:license] = 'GPL'
          next
        end
        if content.match(/ruby/im)
          data[:license] = 'RUBY'
          next
        end
        if content.match(/Academic Free License|AFL/im)
          data[:license] = 'AFL'
          next
        end
        if content.match(/Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met/)
          data[:license] = 'BSD'
          next
        end
        if content.match(/apache/im)
          data[:license] = 'APACHE'
          next
        end
      end
    end
  end
  
  gems.each do |gemname,data|
    puts "#{data[:folder]}\t#{data[:license_file] || 'NOT FOUND'}\t#{data[:license] || 'UNKNOWN'}"
  end
  
end