launch many ruby projects by typing 'irb' from the root dir of the project

.irbrc

#!/usr/bin/ruby
# Save this file as .irbrc in the root of your home directory...  This will allow
# you to load multiple different enviroments by simply typing 'irb' from your console.
#
# This file includes tab compleation and irb history.
#
# For example, after saving this file you can:
# type: irb  instead of ./script/console
# type: irb  instead of irb   (followed by "require 'lib/init.rb'")


require 'irb/completion'
require 'pp'
IRB.conf[:AUTO_INDENT] = true
 
require 'irb/ext/save-history'
IRB.conf[:SAVE_HISTORY] = 100
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history"
 
 
current_path = Dir.pwd
working_dir = current_path.split(File::Separator).last
 
# Load Cilantro apps:  http://github.com/dcparker/cilantro
if File.exists?('lib/cilantro.rb')
  require 'lib/cilantro'
  Cilantro.load_environment(:irb)
  puts "Custom environment loaded."
 
# load Rails apps:  http://www.rubyonrails.org
elsif File.exists?('script/console') && File.exists?('config/boot.rb')
  unless Object.const_defined?("RAILS_ROOT")
     require 'config/boot' unless Object.const_defined?("RAILS_ROOT")
     require 'commands/console' if ENV['RAILS_ENV'].nil?
   end
  puts "Rails #{Rails.version} #{RAILS_ENV} environment loaded."
 
# load other apps
elsif File.exists?('config/init.rb')
  require 'config/init.rb'
  puts "Custom environment loaded."
 
# load under-development gems
elsif File.exists?("lib/#{working_dir}.rb")
  require "lib/#{working_dir}"
  puts "Custom environment loaded."

# Load else
else
  puts "Standard IRB: No special environment loaded."
end