Ruby升级后no such file to load -- readline解决办法

升级ruby和rails后进入script/consle出现：

/usr/local/lib/ruby/1.8/irb/completion.rb:10:in `require': no such file to load -- readline (LoadError)  

        from /usr/local/lib/ruby/1.8/irb/completion.rb:10  

        from /usr/local/lib/ruby/1.8/irb/init.rb:252:in `require'  

        from /usr/local/lib/ruby/1.8/irb/init.rb:252:in `load_modules'  

        from /usr/local/lib/ruby/1.8/irb/init.rb:250:in `each'  

        from /usr/local/lib/ruby/1.8/irb/init.rb:250:in `load_modules'  

        from /usr/local/lib/ruby/1.8/irb/init.rb:21:in `setup'  

        from /usr/local/lib/ruby/1.8/irb.rb:54:in `start'  

        from /usr/local/bin/irb:13  

解决办法：

第一步：确认是否安装了libncurses5-dev libreadline5-dev ,如果没有安装，就用 

   sudo apt-get install libncurses5-dev libreadline5-dev 进行安装 

第二步： 

cd /usr/src/ruby-1.8.7/ext/readline  

ruby extconf.rb  

make  

sudo make install