a check of ENV inheritance

env_inheritance.rb

# This script demonstrates that ENV variables are inherited
# in system calls.  The printout (assuming VARIABLE is not
# set beforehand) is:
#
#   % ruby env_inheritance.rb
#   before: 
#   reset:  blue
#   system: blue
#   popen:  blue
#   after:  blue
#

puts "before: #{ENV["VARIABLE"]}"
ENV["VARIABLE"] = "blue"
puts "reset:  #{ENV["VARIABLE"]}"
system   %q{ruby -e 'puts "system: #{ENV["VARIABLE"]}"; ENV["VARIABLE"] = "green"'}
IO.popen %q{ruby -e 'puts "popen:  #{ENV["VARIABLE"]}"; ENV["VARIABLE"] = "green"'} do |io|
  puts io.read
end
puts "after:  #{ENV["VARIABLE"]}"