今天在使用 yeoman 的时候，当我运行 grunt serve 命令的时候，出现如下提示：
1、Error: Cannot find module 'load-grunt-tasks'
$ grunt serve
Loading "Gruntfile.js" tasks...ERROR >> Error: Cannot find module 'load-grunt-tasks' Warning: Task "serve" not found. Use --force to continue. Aborted due to warnings.
该错误是因为没有安装 load-grunt-tasks 插件，我们运行如下命令将，所有该项目依赖的所欲node插件，全部安装，命令如下：
# $ sudo npm install #for mac $ npm install
该命令会将 package.js 中依赖的所有node插件全部安装。
参考文档：http://stackoverflow.com/questions/18114666/grunt-fatal-error-unable-to-find-local-grunt-in-yeoman
2、Warning: Running "compass:server" (compass) task
$ grunt serve
Running "serve" task
Running "clean:server" (clean) task
>> 0 paths cleaned.
Running "wiredep:app" (wiredep) task
Running "wiredep:test" (wiredep) task
Running "wiredep:sass" (wiredep) task
Running "concurrent:server" (concurrent) task
Warning: Running "compass:server" (compass) task
Warning: Command failed: compass --version
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/dependency.rb:296:in `to_specs': Could not find 'compass' (>= 0) among 45 total gem(s) (Gem::LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/dependency.rb:307:in `to_spec'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_gem.rb:47:in `gem'
from /usr/bin/compass:22:in `<main>'
Use --force to continue.
Aborted due to warnings.
Execution Time (2015-04-12 05:32:54 UTC)
loading tasks 5ms ▇▇▇ 5%
compass:server 85ms ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 93%
Total 91ms Use --force to continue.
Aborted due to warnings.
Execution Time (2015-04-12 05:32:50 UTC)
wiredep:app 134ms ▇▇▇ 4%
concurrent:server 3s ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 95%
Total 3.2s
网上搜了一堆blog，最后发现是未安装 compass ，因为我用 yeoman 构建项目的时候，选了使用 sass ，而在yeoman中使用sass则又需要安装 compass （直接使用sass是不需要的）。
参考文档：http://stackoverflow.com/questions/21865609/grunt-need-compass-installed-in-system-path-warning
compass是基于 ruby 的，因此在安装 compass 前，你先需要确定，你的电脑已经安装了 ruby 。
现在我再来安装 compass：
$ gem install compass
安装好 compass 后，在运行 grunt serve 命令，就会自动打开 http://localhost:9000 。
你就会看到 yeoman 构建工具，创建的默认页面。