It gives the exception when I run “rails console”. This is how I resolve the problem. My environment: Ubuntu 12.04, Ruby 1.9.2p290 build from source, Rails 3.0.10

For ruby builded frome source code: 1. Make sure you have libreadline-dev and libncurses5-dev 2. Go to the ruby source code directory 3. Build readline up

Install libreadline-dev

	sudo apt-get install libreadline-dev libncurses5-dev
	or Some older ubuntu didn't have libreadline-dev try:
	sudo apt-get install libreadline5-dev libncurses5-dev

cd (ruby_sourcecode_dir)/ext/readline ruby extconf.rb make sudo make install

For RVM: Basically same to above. But the path to ext/readline is under .rvm directory. eg. /home/your_name/.rvm/src/ruby-1.9.2-p290/ext/readline