$ gem install -y ruby-opengl -r
INFO:  `gem install -y` is now default and will be removed
INFO:  use --ignore-dependencies to install only the gems you list
ERROR:  While executing gem ... (Errno::EACCES)
    Permission denied - /usr/lib/ruby/gems/1.8/cache/mkrf-0.2.3.gem
dexter@shodan:~/software/gltail-0.1.0$ sudo gem install -y ruby-opengl -r
INFO:  `gem install -y` is now default and will be removed
INFO:  use --ignore-dependencies to install only the gems you list
Building native extensions.  This could take a while...
ERROR:  Error installing ruby-opengl:
        ERROR: Failed to build gem native extension.

rake RUBYARCHDIR=/usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0/lib RUBYLIBDIR=/usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0/lib
/usr/bin/ruby1.8 mkrf_conf.rb
(in /usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0)
rake
gcc  -fPIC -Wall -g -fno-strict-aliasing -O2  -fPIC  -Wall -DRUBY_VERSION=185  -I/usr/include -I/usr/lib/ruby/1.8/i486-linux -I/usr/local/lib/site_ruby/1.8 -I. -c gl-1.3.c
(in /usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0/ext/gl)
In file included from gl-1.3.c:16:
../common/common.h:45:21: error: GL/glut.h: No such file or directory
rake aborted!
Command failed with status (1): [gcc  -fPIC -Wall -g -fno-strict-aliasing -...]
/usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0/ext/gl/Rakefile:29
(See full trace by running task with --trace)
rake aborted!
Command failed with status (1): [rake...]

(See full trace by running task with --trace)


Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/ruby-opengl-0.60.0/gem_make.out