Question

I just wanted to gem install rmagick

and got this:

Building native extensions.  This could take a while...
ERROR:  Error installing rmagick:
    ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb
extconf.rb:1:in `require': no such file to load -- mkmf (LoadError)
    from extconf.rb:1

ImageMagick and libmagickwand-dev is already installed.

Using Ubuntu Linux.

Any help?

Yours, Joern.

Answer 1

use rvm to install ruby (preferred) or use apt-get install ruby ruby-dev

aptitude install build-essential imagemagick libmagickcore-dev libmagickwand-dev
gem install rmagick

–Edit 1–

sudo apt-get install ruby-dev

You will also need ruby-dev (or ruby-full) for successfully compiling the RMagick before gem install.