install_gems.rb

#!/usr/bin/env ruby
# use this to install the same gems you have installed under one ruby in another
# run "gem list > ~/Desktop/gems.txt"
# run "ruby install_gems.rb ~/Desktop/gems.txt"
# You may have to change which ruby you use to run this so the gems get installed
# in the right place, for instance, using the REE ruby specifically while your server
# is running on another version... basically, think about what you're doing.

gems = IO.readlines(ARGV.first)
gems.map! do |g|
  stuff = g.split(' ')
  gem_name = stuff.delete_at(0)
  stuff.map{|v| v.gsub(/[\(\)\,]/, '')}.map{|v| "sudo gem install #{gem_name} -v=#{v}"}
end.flatten!

gems.each do |g|
  puts "running '#{g}'"
  `#{g}`
end