ruby - Rails installation error -

i trying install rails on mac os (mavericks) reason won't let me. have ruby installed. here error , set of gems have:

[~] ruby-2.2.1 $ sudo gem install rails password: error:  error installing rails: invalid gem: package corrupt, exception while verifying: undefined method `size' nil:nilclass (nomethoderror) in /users/garrettgalvin/.rvm/rubies/ruby-2.2.1/lib/ruby/gems/2.2.0/cache/nokogiri-1.6.6.2.gem  actionview (4.2.3) activesupport (4.2.3) bigdecimal (1.2.6) builder (3.2.2) bundler (1.10.5) bundler-unload (1.0.2) erubis (2.7.0) executable-hooks (1.3.2) gem-wrappers (1.2.7) i18n (0.7.0) io-console (0.4.3) json (1.8.1) loofah (2.0.2) mini_portile (0.6.2) minitest (5.7.0) psych (2.0.8) rails-deprecated_sanitizer (1.0.3) rails-dom-testing (1.0.6) rails-html-sanitizer (1.0.2) rake (10.4.2) rdoc (4.2.0) rubygems-bundler (1.4.4) rubygems-update (2.4.8) rvm (1.11.3.9) thread_safe (0.3.5) tzinfo (1.2.2) 

any ideas?

you should never install gems using sudo.

if, while installing package, gem corruption errors, have installation again , make sure delete respective gem in .rvm file. (search , delete of gems name.)