将cocoapods更新到最新版本不会做任何事情

我目前正在使用cocoapods 0.26.2(输出pod --version).我想将其更新为0.29.0.

我跑sudo gem update了似乎没有对cocoapods宝石做任何事情.所以,根据cocoapods.org的建议,我试过:

sudo gem uninstall cocoapods
sudo gem install cocoapods

那似乎安装了cocoapods 0.29.0.但是,当我跑的pod --version时候仍然告诉我,我在0.26.2.

$ which pod
/usr/bin/pod

我尝试重命名/usr/bin/pod为其他东西,然后再次尝试卸载/重新安装,但它没有放入pod二进制文件/usr/bin.然而它确实放了一个pod二进制文件/usr/local/Cellar/ruby/2.0.0-p247/bin.我真的需要将奇数和版本的硬编码路径添加到我的$PATH?? 为什么之前安装了cocoapods /usr/bin？

我的宝石环境:

RubyGems Environment:
  - RUBYGEMS VERSION: 2.1.9
  - RUBY VERSION: 2.0.0 (2013-06-27 patchlevel 247) [x86_64-darwin12.5.0]
  - INSTALLATION DIRECTORY: /usr/local/Cellar/ruby/2.0.0-p247/lib/ruby/gems/2.0.0
  - RUBY EXECUTABLE: /usr/local/Cellar/ruby/2.0.0-p247/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/local/Cellar/ruby/2.0.0-p247/bin
  - SPEC CACHE DIRECTORY: /Users/michael/.gem/specs
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-darwin-12
  - GEM PATHS:
     - /usr/local/Cellar/ruby/2.0.0-p247/lib/ruby/gems/2.0.0
     - /Users/michael/.gem/ruby/2.0.0
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /usr/local/bin
     - /usr/local/sbin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /usr/local/bin
     - /opt/X11/bin

我正在运行OS X 10.9.1.