➜ ruby -v
jruby 1.7.8 (1.9.3p392) 2013-11-14 0ce429e on Java HotSpot(TM) 64-Bit Server VM 1.6.0_65-b14-462-11M4609 [darwin-x86_64]
➜ ruby -ropen3 -e 'Open3.capture2e("hostname")'
file:/Users/myron/.rubies/jruby-1.7.8/lib/jruby.jar!/jruby/kernel19/process.rb:14 warning: unsupported spawn option: in
TypeError: wrong exec option: [:out, :err]
  _spawn_internal at org/jruby/RubyProcess.java:1067
            spawn at file:/Users/myron/.rubies/jruby-1.7.8/lib/jruby.jar!/jruby/kernel19/process.rb:13
            spawn at file:/Users/myron/.rubies/jruby-1.7.8/lib/jruby.jar!/jruby/kernel19/kernel.rb:29
        popen_run at /Users/myron/.rubies/jruby-1.7.8/lib/ruby/1.9/open3.rb:204
          popen2e at /Users/myron/.rubies/jruby-1.7.8/lib/ruby/1.9/open3.rb:199
        capture2e at /Users/myron/.rubies/jruby-1.7.8/lib/ruby/1.9/open3.rb:365
           (root) at -e: