in `require': cannot load such file — httparty (LoadError)

问题

My default ruby is 2.0.0p384.

A ruby script has:

#!/usr/bin/env ruby
require 'rubygems'
require 'httparty'

If the above header is changed to:

#!/usr/bin/ruby1.9.1

the script runs fine.

/var/lib/gems/2.0.0/gems/httparty-0.13.5 exists.

I can't understand why running the script with the 2.0.0 ruby gives:

/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:53:in require': cannot load such file -- httparty (LoadError) from usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:53:inrequire' from ./check_pingdom:30:in `'

来源：https://stackoverflow.com/questions/30584455/in-require-cannot-load-such-file-httparty-loaderror