no such file to load -- readline

安装rails后进入控制台出现如题错误：

/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

1	rvm pkg installreadline

2	rvm remove 1.9.2

3	rvm install1.9.2 --with-readline-dir=$rvm_path/usr

这中方法比较慢  还有一种比较好的方法，实践可用

On Debian/Ubuntu:

apt-get install libreadline-dev 

Or on RHEL/CentOS, try

yum install readline-devel

  然后进入./rvm/src/ruby_path/ext /readline   ruby extconf.rb   

make && make install

然后就ok了