How do I fix the “You don't have write permissions into the /usr/bin directory” error when installing Rails?

Question

I\'m trying to install Rails 3 on a brand new MacBook Pro running OS X 10.6.3, Ruby 1.8.7, and Rails 2.3.5 and I\'m wondering if I\'ve hosed myself. So far, I\'ve run these

Answer 1

For me, something different worked, that I found in on this answer from a similar question. Probably won't help OP, but maybe someone like me that had a similar problem.

You should indeed use rvm, but as no one explained to you how to do this without rvm, here you go:

sudo gem install tzinfo builder memcache-client rack rack-test rack-mount \
  abstract erubis activesupport mime-types mail text-hyphen text-format   \
  thor i18n rake bundler arel railties rails --prerelease --force