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