ruby's "system" call suddenly contradicts what I saw running the "rake tasks" in shell

gistfile1.rb

# try running a rake task like
RAILS_ENV=test ANOTHER=imaginary rake foo:bar

# and run
rake foo:bar RAILS_ENV=test ANOTHER=imaginary

# both run right?

# now do this
ruby -e "system 'rake foo:bar RAILS_ENV=test ANOTHER=imaginary'"

# and this
ruby -e "system 'RAILS_ENV=test ANOTHER=imaginary rake foo:bar'"

# notice last one is quick to return, ignored?

# what is with ruby's system then?

# to add more load to the grey matter there then do this
ruby -e "system 'RAILS_ENV=test ANOTHER=imaginary rake foo:bar && rake foo:bar RAILS_ENV=test ANOTHER=imaginary'"