我对使用grunt、compass和sass还比较陌生，无法正常运行。我的Redhat系统上安装了Drupal 7，在站点主题目录中尝试运行'grunt compass'时出现以下错误：
Running "compass:dist" (compass) task
Warning: You need to have Ruby and Compass installed and in your system PATH for this task to work. More info: https://github.com/gruntjs/grunt-contrib-compass Use --force to continue.
Aborted due to warnings.
我已经安装了Grunt、Bower，并使用'bundle install'安装所需的gems。当我运行'gem list'时，得到以下结果：
bigdecimal (1.2.4)
breakpoint (2.0.7)
bundler (1.6.2)
bundler-unload (1.0.2)
chunky_png (1.3.1)
compass (0.12.6)
compass-normalize (1.4.3)
executable-hooks (1.3.1)
fssm (0.2.10)
gem-wrappers (1.2.4)
io-console (0.4.2)
json (1.8.1)
kss (0.5.0)
minitest (4.7.5)
psych (2.0.3)
rake (10.1.0)
rdoc (4.1.0)
ruby (0.1.0)
rubygems-bundler (1.4.3)
rubygems-update (2.2.2)
rvm (1.11.3.9)
sass (3.2.19)
test-unit (2.1.1.0)
zurb-foundation (4.3.2)
看起来我已经拥有了所有需要的宝石(gems)。然后我通过“echo $PATH”查看了我的路径设置，得到了以下内容：
/home/ec2-user/.rvm/gems/ruby-2.1.1/bin:/home/ec2-user/.rvm/gems/ruby-2.1.1@global/bin:/home/ec2-user/.rvm/rubies/ruby-2.1.1/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/opt/aws/bin:/home/ec2-user/bin:/home/ec2-user/.rvm/bin
我查看了路径，发现在 /usr/bin 中有 ruby2.0，在 /home/ec2-user/bin 中有 compass，因此这些安装似乎都在系统路径中。
当我从命令行运行 'ruby2.0' 时，会得到以下结果：
/usr/local/share/ruby/site_ruby/2.0/rubygems/ext/builder.rb:12:in `<class:Builder>': uninitialized constant Gem::UserInteraction (NameError)
from /usr/local/share/ruby/site_ruby/2.0/rubygems/ext/builder.rb:10:in `<top (required)>'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/ext.rb:13:in `<top (required)>'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:1431:in `build_extensions'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/stub_specification.rb:60:in `build_extensions'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/basic_specification.rb:56:in `contains_requirable_file?'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:925:in `block in find_inactive_by_path'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:924:in `each'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:924:in `find'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:924:in `find_inactive_by_path'
from /usr/local/share/ruby/site_ruby/2.0/rubygems.rb:185:in `try_activate'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:132:in `rescue in require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:144:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/user_interaction.rb:8:in `<top (required)>'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/config_file.rb:7:in `<top (required)>'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:1430:in `build_extensions'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/stub_specification.rb:60:in `build_extensions'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/basic_specification.rb:56:in `contains_requirable_file?'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:925:in `block in find_inactive_by_path'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:924:in `each'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:924:in `find'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/specification.rb:924:in `find_inactive_by_path'
from /usr/local/share/ruby/site_ruby/2.0/rubygems.rb:185:in `try_activate'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:132:in `rescue in require'
from /usr/local/share/ruby/site_ruby/2.0/rubygems/core_ext/kernel_require.rb:144:in `require'
from <internal:abrt_prelude>:2:in `<compiled>'
当我运行简单的“ruby”时，什么都不会发生。 “grunt compass”是否在寻找“ruby”，而我却有“ruby2.0”？我需要用ruby -> ruby2.0创建符号链接吗？
当我从命令行运行“compass”时，我得到：
使用方法：compass help [command]
Description:
The Compass Stylesheet Authoring Framework helps you
build and maintain your stylesheets and makes it easy
for you to use stylesheet libraries provided by others.
等等。
非常感谢您的意见。