Ruby + ImageMagick = RMagick on CentOs

Got there in the end. The main problem was that subsequent make install commands failed to copy the new .so files to the right place. I also discovered I had the same issue with readline and needed to install the readline-devel package (via yum). So I did

sudo yum install readline-devel
cd ext/curses
sudo ruby extconf.rb
cd ../readline
sudo ruby extconf.rb
cd ../..
sudo make
sudo make install
sudo cp ext/curses/curses.so ext/readline/readline.so /usr/local/lib/ruby/1.8/x86_64-linux/

Obviously you may want to use an i386 directory if you are not on a 64 bit platform.

If you install ncurses-devel and readline-devel (as well as the other packages mentioned in the article) before you download and compile ruby you shouldn't need to do any of this.

Try RMagick instead of rmagick:

$ irb
irb(main):001:0> require 'RMagick'
=> true
irb(main):003:0> puts Magick::Long_version
This is RMagick 2.13.1 ($Date: 2009/12/20 02:33:33 $) Copyright (C) 2009 by Timothy P. Hunter
Built with ImageMagick 6.6.8-5 2011-07-08 Q16 http://www.imagemagick.org
Built for ruby 1.8.7
Web page: http://rmagick.rubyforge.org
Email: rmagick@rubyforge.org
=> nil
irb(main):004:0>