gems2gemfile

#!/usr/bin/env ruby
require 'rubygems'
gems = Gem.source_index.search(Gem::Dependency.new(//, Gem::Requirement.default))
gems.each do |gem|
  puts "gem '#{gem.name}', '#{gem.version.to_s}'"
end

gistfile2.txt

$ gem list

*** LOCAL GEMS ***

bundler (1.0.7)
rack (1.0.1)
rake (0.8.7)
sqlite3-ruby (1.3.2)
xml-simple (1.0.12)


$ gems2gemfile 
gem 'bundler', '1.0.7'
gem 'rack', '1.0.1'
gem 'rake', '0.8.7'
gem 'sqlite3-ruby', '1.3.2'
gem 'xml-simple', '1.0.12'

>> Copy and paste into Gemfile

I had a simple problem. I just set up a legacy Rails 2.3 app and spent the whole afternoon hunting down dependencies. Since I used rvm, my gemset contained exactly the dependencies I needed. Now I wanted to turn that gemset into a Gemfile.