Question

我just cleaned rvm和ruby并重新安装它。我正在尝试安装rails但是我收到了这个错误：

gem install rails -v 3.2.9

Building native extensions.  This could take a while...
ERROR:  Error installing rails:
    ERROR: Failed to build gem native extension.

        /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
    from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from extconf.rb:1:in `<main>'


Gem files will remain installed in /var/lib/gems/1.9.1/gems/json-1.8.1 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/json-1.8.1/ext/json/ext/generator/gem_make.out

如果我使用bundle install Gemfile以及更多宝石运行rails 3.2.9，我会收到此错误：

An error occurred while installing json (1.8.1), and Bundler cannot continue.
Make sure that `gem install json -v '1.8.1'` succeeds before bundling.

猜猜是什么。运行建议的命令会给我另一个错误：

Building native extensions.  This could take a while...
ERROR:  Error installing json:
    ERROR: Failed to build gem native extension.

        /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
    from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from extconf.rb:1:in `<main>'


Gem files will remain installed in /var/lib/gems/1.9.1/gems/json-1.8.1 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/json-1.8.1/ext/json/ext/generator/gem_make.out

Answer 1

可能重复：

根据您的ruby版本，运行：

sudo apt-get install ruby1.9.1-dev

Answer 2

一个简单的谷歌搜索指向此早期的stackoverflow问题：

Why do I get an error installing the JSON gem in Ubuntu?

安装ruby1.9.1-dev软件包应该为你解决这个问题：

sudo apt-get install ruby1.9.1-dev

无法安装rails 3.2.9：无法构建gem native扩展

2 个答案: