Install gems from a gem list dump

gemit.rb

gem_cmd = ENV["GEM_CMD"] || 'sudo gem'

STDIN.map { |l| l.strip }.each { |l| 
  gem, versions = l.split(' ', 2)
  versions = versions.gsub(/[\(\)]/, '').split(', ')
  
  versions.each { |version|
    cmd = "#{gem_cmd} install #{gem} -v #{version}"
    puts cmd if ENV["PRETEND"] or ENV["ECHO"]
    system cmd unless ENV["PRETEND"]
  }
}