help me solve the mystery of bundle

[Jedrin]

 I tried to copy all my gems from one machine to another because the network was down and thus I could not do 'gem install'.

After copying those, when I try to do "jruby -S bundle install" it can't find bundle, though if I copied my gems over, supposedly it's there. How does jruby know the path to bundle ? When I run bundle, how can I figure out where it is
running from on windows, this would be sort of like "which" in linux