ruby on rails 3 - rmagick gem install "Can't find Magick-config"

Question

I get the error shown below when attempting to install the rmagick gem. I am on Snowleopard 10.6 using RVM, Ruby 1.9.2-head and Rails 3.05. Responses to similar questions recommended installing ImageMagick, which I successfully did. Other suggested installing the "libmagick9-dev library", however, I can not figure out how to do this.

I'm a new developer, and any assistance or directions to an existing explanation or resource is greatly appreciated. Thanks!

jjdevenuta(opal)$ gem install rmagick
Fetching: rmagick-2.13.1.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing rmagick:
ERROR: Failed to build gem native extension.

/Users/jjdevenuta/.rvm/rubies/ruby-1.9.2-head/bin/ruby extconf.rb
checking for Ruby version >= 1.8.5... yes
checking for gcc... yes
checking for Magick-config... no
Can't install RMagick 2.13.1. Can't find Magick-config in /Users/jjdevenuta/.rvm/gems/ruby-1.9.2-head@rails3/bin:/Users/jjdevenuta/.rvm/gems/ruby-1.9.2-head@global/bin:/Users/jjdevenuta/.rvm/rubies/ruby-1.9.2-head/bin:/Users/jjdevenuta/.rvm/bin:/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/git/bin:/usr/X11/bin

*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/jjdevenuta/.rvm/rubies/ruby-1.9.2-head/bin/ruby

UPDATE If you're a Mac/OS X user I would HIGHLY recommend using Homebrew as your package installer/manager. You can find it HERE. Since originally asking this question I have removed all my prior installs of things like rmagick and imagemagick, and reinstalled them using Homebrew. Super easy with a huge catalog of packages, and updates/uninstalls are a cinch as well!

Answer 1

When building native Ruby gems, sometimes you'll get an error containing "ruby extconf.rb". This is often caused by missing development libraries for the gem you're installing, or even Ruby itself.

Do you have apt installed on your machine? If not, I'd recommend installing it, because it's a quick and easy way to get a lot of development libraries.

If you see people suggest installing "libmagick9-dev", that's an apt package that you'd install with:

$ sudo apt-get install libmagickwand-dev imagemagick

or on centOs:

$ yum install ImageMagick-devel

On Mac OS, you can use Homebrew:

$ brew install imagemagick