ubuntu14.04にgemでrmagickをインストール

まず、gem install してみる

$ gem install rmagick -v '2.14.0'
Building native extensions.  This could take a while...
ERROR:  Error installing rmagick:
    ERROR: Failed to build gem native extension.

    /home/hoge/.rbenv/versions/2.1.5/bin/ruby extconf.rb
checking for gcc... yes
checking for Magick-config... yes
checking for outdated ImageMagick version (<= 6.4.9)... no
checking for Ruby version >= 1.8.5... yes
checking for stdint.h... yes
checking for sys/types.h... yes
checking for wand/MagickWand.h... no

Can't install RMagick 2.14.0. Can't find MagickWand.h.
*** 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=/home/hoge/.rbenv/versions/2.1.5/bin/ruby

extconf failed, exit code 1

Gem files will remain installed in /home/hoge/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/rmagick-2.14.0 for inspection.
Results logged to /home/hoge/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/extensions/x86_64-linux/2.1.0-static/rmagick-2.14.0/gem_make.out

どうやら、なにかライブラリーが足りていない感じ

以下のコマンドを実行

 $ sudo apt-get  install imagemagick libmagickcore-dev libmagickwand-dev 

再度gem iするとインストールされた

$ gem install rmagick -v '2.14.0'
Building native extensions.  This could take a while...
Successfully installed rmagick-2.14.0
1 gem installed