我在 centos6.4 中通过 yum -y install ruby rubygems 安装了 ruby 和 rubygems，然后再通过 gem install fpm，发现出错，google 了一圈，只找到要更换成 taobao 源的方案，于是：

gem sources --remove http://rubygems.org/

gem sources -a http://ruby.taobao.org/

gem sources -l

*** CURRENT SOURCES ***

http://ruby.taobao.org/

再然后：

gem install fpm

出现以下错误： ... Exception Errno::EEXIST' at /usr/lib/ruby/1.8/fileutils.rb:243 - File exists - /usr/lib/r uby/gems/1.8/gems/json-1.8.1/tests Building native extensions. This could take a while... ExceptionGem::InstallError' at /usr/lib/ruby/site_ruby/1.8/rubygems/ext/builder.rb:49 - extconf failed:

/usr/bin/ruby extconf.rb mkmf.rb can't find header files for ruby at /usr/lib/ruby/ruby.h

Exception `Gem::Installer::ExtensionBuildError' at /usr/lib/ruby/site_ruby/1.8/rubygems/in staller.rb:483 - ERROR: Failed to build gem native extension.

/usr/bin/ruby extconf.rb mkmf.rb can't find header files for ruby at /usr/lib/ruby/ruby.h

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/json-1.8.1 for inspection. Results logged to /usr/lib/ruby/gems/1.8/gems/json-1.8.1/ext/json/ext/generator/gem_make.o ut

ERROR: Error installing fpm: ERROR: Failed to build gem native extension.

/usr/bin/ruby extconf.rb mkmf.rb can't find header files for ruby at /usr/lib/ruby/ruby.h

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/json-1.8.1 for inspection. Results logged to /usr/lib/ruby/gems/1.8/gems/json-1.8.1/ext/json/ext/generator/gem_make.o ut

怎么解决？我只想装 fpm 而已。

实际上，我昨天另外一个虚拟机 debian7 中，是可以直接 gem install fpm 的，都不需要更改 sources。