Can't install RMagick 2.13.1. Can't find Magick-config

command: sudo apt-get install libmagickwand-dev

It isn't quite the answer to the question, but the recommended way of installing Imagemagick and Rmagick on Mac is through homebrew. It's the only way I could get Imagemagick and Rmagick playing nicely together on Mac.

For Ubuntu (11.10+) try installing the libmagick++-dev package.

For other Linux distributions, try installing the libmagick-dev package.