Thor: Create new RVM gemsets by example for new Rails projects

gemset.thor

# kate: syntax ruby;
# -*- mode: ruby -*-
# vi: set ft=ruby :

require 'rubygems'
require 'thor'

class Gemset < Thor
  include Thor::Actions

  desc "new GEMSET_NAME", "start a new gemset from another example gemset"
  method_option :source, :default=>'new-project--rails3', :aliases=>'-s', :desc => 'rvm gemset to initialize the gemset. You need at least some gems like rails or hobo to create a project'
  
  def new(target)
    source=options.source
    sdir= sh( source, "rvm gemset gemdir").strip
    tdir= sh( target, "rvm gemset gemdir", true).strip
#     puts "SOURCE=#{source} #{sdir}, TARGET=#{target} #{tdir}"
    run "cp -a #{sdir}/* #{tdir}/"
  end

  desc "sh GEMSET_NAME, cmd", "run a command within a gemset"
  def sh(name, cmd, create=false)
    cmd= %Q{bash -lc "source $HOME/.rvm/scripts/rvm; rvm use #{create ? '--create' : ''} @#{name} >/dev/null &&  #{cmd}"}
    puts cmd
    answer = `#{cmd}`
    # raise "gemset #{name} does not exist" if answer =~ /does not/
    puts answer
    answer
  end

end