在更新cocoapods时，出现错误，找了半天终于在stackoverflow上找到答案：
/Users/myusername/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:298:in`to_specs': Could not find 'cocoa pods' (>= 0) among 37 total gem(s) (Gem::LoadErrorfrom
/Users/quique123/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:309:in `to_spec'from
/Users/quique123/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/core_ext/kernel_gem.rb:53:in `gemfrom
/Users/quique123/.rvm/rubies/ruby-1.9.3-p194/bin/pod:22:in`'
答案：
Do not usesudo gem install cocoapodsif you havervminstalled. It creates a few problems. Follow these steps to fix your cocoapods installation:
Uninstall Cocoapods:
sudo gem uninstall cocoapods
Make sure you're on the latest Ruby:
which ruby
Installcocoapodswithoutsudo:
gem install cocoapods-V--no-ri--no-rdoc# V: Verbose; no-ri,no-rdoc: Do not install documentation
Set up Cocoapods:
pod setup
Should work now.
原来是我以前安装是用了sudo，导致位置不对
重新设置一下就行了。
