最近，我安装了OS X Mavericks操作系统，但它似乎破坏了我的开发环境。在运行“rails new first_app”命令后，我收到以下消息：
Your user account isn't allowed to install to the system Rubygems.
You can cancel this installation and run:
bundle install --path vendor/bundle
to install the gems into ./vendor/bundle/, or you can enter your password
and install the bundled gems to Rubygems using sudo.
Password:
Fetching gem metadata from https://rubygems.org/..........
Fetching additional metadata from https://rubygems.org/..
Resolving dependencies...
Using rake (10.1.1)
Using i18n (0.6.9)
Using minitest (4.7.5)
Using multi_json (1.9.0)
Using atomic (1.1.15)
Using thread_safe (0.2.0)
Errno::EACCES: Permission denied - /Library/Ruby/Gems/2.0.0/build_info/tzinfo-0.3.39.info
An error occurred while installing tzinfo (0.3.39), and Bundler cannot continue.
Make sure that `gem install tzinfo -v '0.3.39'` succeeds before bundling.
我随后就按照要求完成了：
christohersmbp2:hartl christopherspears$ gem install tzinfo -v '0.3.39'
ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.0.0 directory.
奇怪的是我确实安装了rbenv。事实上，在尝试调试此问题时，我升级了rbenv：
christohersmbp2:~ christopherspears$ brew update
Already up-to-date.
christohersmbp2:~ christopherspears$ brew upgrade rbenv ruby-build
Warning: A newer Command Line Tools release is available
Update them from Software Update in the App Store.
Error: rbenv-0.4.0 already installed
Error: ruby-build-20140225 already installed
然而，当我尝试从命令行调用rbenv时，我会收到这个错误消息：
christohersmbp2:hartl christopherspears$ rbenv
-bash: rbenv: command not found
christohersmbp2:~ christopherspears$ rbenv rehash
-bash: rbenv: command not found
我认为我已经正确设置了路径：
christohersmbp2:hartl christopherspears$ echo $PATH
/usr/local/share/python:/Users/christopherspears/.rbenv/bin:/Users/christopherspears/bin:/usr/local/heroku/bin:/usr/local/share/npm/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin
这是我在.bash_profile文件中的内容：
# rbenv stuff
export PATH="$HOME/.rbenv/bin:$PATH"
if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi
奇怪的是，我想我使用的是版本文件夹中的Ruby版本：
christohersmbp2:versions christopherspears$ pwd
/Users/christopherspears/.rbenv/versions
christohersmbp2:versions christopherspears$ ls
2.0.0-p247/
christohersmbp2:versions christopherspears$ ruby -v
ruby 2.0.0p247 (2013-06-27 revision 41674) [universal.x86_64-darwin13]
任何提示吗？我似乎一切都做得正确。
更新：
我下载并安装了Xcode命令行工具，但好像没用：
christohersmbp2:~ christopherspears$ rbenv -bash: rbenv：未找到命令