安装gem install bundler的时候提示报错
ERROR:  Loading command: install (LoadError)
    no such file to load -- zlib
ERROR:  While executing gem ... (NameError)
    uninitialized constant Gem::Commands::InstallCommand
 
根据提示是缺少了zlib库
然后安装yum install zlib*
再次运行gem install bundler  还是报错
原来ruby有自身提供的zlib包
进入ruby目录
然后在
cd ext/zlib
ruby ./extconf.rb
make
make install
 
再次运行gem install bundler  
ok