Making a compass executable that runs specific versions of compass

compass-custom

#!/usr/bin/env ruby_executable_hooks
#
# This file was generated by RubyGems.
#
# The application 'compass' is installed as part of a gem, and
# this file is here to facilitate running it.
#

require 'rubygems'

version_arg = ARGV.shift if ARGV.first =~ /^(?:\d+.)+\d+$/
version     = version_arg || ">= 0"

if ARGV.first
  str = ARGV.first
  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
    version = $1
    ARGV.shift
  end
end

gem 'compass', version
load Gem.bin_path('compass', 'compass', version)

example

# Create the custom executable
$ vim ~/.rvm/gems/ruby-2.1.2/bin/compass-custom
# In the editor, enter the code in the snippet file above and save the file
# Then make the file executable
$ chmod +ux ~/.rvm/gems/ruby-2.1.2/bin/compass-custom
# Then run it, passing as FIRST argument the version you want to use
$ compass-custom 1.0.3 [...]