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':nosuchfiletoload--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-devlibreadline5-dev,如果没有安装，就用
sudoapt-getinstalllibncurses5-devlibreadline5-dev进行安装
第二步：
cd/usr/src/ruby-1.8.7/ext/readline rubyextconf.rb make sudomakeinstall