为什么当我使用 sudo 运行 ruby 的 '$:' 或 '$LOAD_PATH' 时会发生变化？答案

【问题标题】：Why does ruby's '$:' or '$LOAD_PATH' change when I run it with sudo?为什么当我使用 sudo 运行 ruby 的 '$:' 或 '$LOAD_PATH' 时会发生变化？
【发布时间】：2010-07-11 22:29:55
【问题描述】：

我正在尝试以 root 身份运行 ruby 脚本。当我尝试require 宝石时，ruby 说找不到它。这是因为$:

$ ruby -e "puts $:"
/opt/local/lib/ruby/gems/1.9.1/gems/activesupport-3.0.0.beta4/lib
/opt/local/lib/ruby/gems/1.9.1/gems/cgi_multipart_eof_fix-2.5.0/lib
/opt/local/lib/ruby/gems/1.9.1/gems/daemons-1.1.0/lib
/opt/local/lib/ruby/gems/1.9.1/gems/eventmachine-0.12.10/lib
/opt/local/lib/ruby/gems/1.9.1/gems/fastthread-1.0.7/lib
/opt/local/lib/ruby/gems/1.9.1/gems/fastthread-1.0.7/ext
/opt/local/lib/ruby/gems/1.9.1/gems/fastthread-1.0.7/bin
/opt/local/lib/ruby/gems/1.9.1/gems/gem_plugin-0.2.3/bin
/opt/local/lib/ruby/gems/1.9.1/gems/gem_plugin-0.2.3/lib
/opt/local/lib/ruby/gems/1.9.1/gems/json_pure-1.4.3/bin
/opt/local/lib/ruby/gems/1.9.1/gems/json_pure-1.4.3/lib
/opt/local/lib/ruby/gems/1.9.1/gems/mongrel-1.1.5/bin
/opt/local/lib/ruby/gems/1.9.1/gems/mongrel-1.1.5/lib
/opt/local/lib/ruby/gems/1.9.1/gems/msgpack-0.4.3/lib
/opt/local/lib/ruby/gems/1.9.1/gems/nestful-0.0.2/lib
/opt/local/lib/ruby/gems/1.9.1/gems/nokogiri-1.4.2/bin
/opt/local/lib/ruby/gems/1.9.1/gems/nokogiri-1.4.2/lib
/opt/local/lib/ruby/gems/1.9.1/gems/num_to_bytes-1.4.1/ext
/opt/local/lib/ruby/gems/1.9.1/gems/num_to_bytes-1.4.1/bin
/opt/local/lib/ruby/gems/1.9.1/gems/open4-1.0.1/lib
/opt/local/lib/ruby/gems/1.9.1/gems/rack-1.2.1/bin
/opt/local/lib/ruby/gems/1.9.1/gems/rack-1.2.1/lib
/opt/local/lib/ruby/gems/1.9.1/gems/rake-0.8.7/bin
/opt/local/lib/ruby/gems/1.9.1/gems/rake-0.8.7/lib
/opt/local/lib/ruby/gems/1.9.1/gems/ruby-processing-1.0.9/bin
/opt/local/lib/ruby/gems/1.9.1/gems/ruby-processing-1.0.9/lib
/opt/local/lib/ruby/gems/1.9.1/gems/ruby_parser-2.0.4/bin
/opt/local/lib/ruby/gems/1.9.1/gems/ruby_parser-2.0.4/lib
/opt/local/lib/ruby/gems/1.9.1/gems/rubyforge-2.0.4/bin
/opt/local/lib/ruby/gems/1.9.1/gems/rubyforge-2.0.4/lib
/opt/local/lib/ruby/gems/1.9.1/gems/sexp_processor-3.0.4/lib
/opt/local/lib/ruby/gems/1.9.1/gems/sinatra-1.0/lib
/opt/local/lib/ruby/gems/1.9.1/gems/thin-1.2.7/bin
/opt/local/lib/ruby/gems/1.9.1/gems/thin-1.2.7/lib
/opt/local/lib/ruby1.9/site_ruby/1.9.1
/opt/local/lib/ruby1.9/site_ruby/1.9.1/i386-darwin10
/opt/local/lib/ruby1.9/site_ruby
/opt/local/lib/ruby1.9/vendor_ruby/1.9.1
/opt/local/lib/ruby1.9/vendor_ruby/1.9.1/i386-darwin10
/opt/local/lib/ruby1.9/vendor_ruby
/opt/local/lib/ruby1.9/1.9.1
/opt/local/lib/ruby1.9/1.9.1/i386-darwin10
.
$ sudo ruby -e "puts $:"
/opt/local/lib/ruby1.9/site_ruby/1.9.1
/opt/local/lib/ruby1.9/site_ruby/1.9.1/i386-darwin10
/opt/local/lib/ruby1.9/site_ruby
/opt/local/lib/ruby1.9/vendor_ruby/1.9.1
/opt/local/lib/ruby1.9/vendor_ruby/1.9.1/i386-darwin10
/opt/local/lib/ruby1.9/vendor_ruby
/opt/local/lib/ruby1.9/1.9.1
/opt/local/lib/ruby1.9/1.9.1/i386-darwin10
.

为什么会这样？

【问题讨论】：

普通用户和 sudo 用户的 $PATH 是否相同？
@theIV：是的 - echo $PATH 和 sudo echo $PATH 具有相同的输出。你是这个意思吗？

标签： ruby rubygems sudo file-not-found load-path

【解决方案1】：

试试sudo -E ruby -e "puts $:"。

来自sudo 手册页：

   -E          The -E (preserve environment) option will override the env_reset option in sudoers(5)).
               It is only available when either the matching command has the SETENV tag or the setenv
               option is set in sudoers(5).

【讨论】：

修复它。我怎样才能使它不必输入-E？
您能否详细说明上面一行中发生了什么？不过，这听起来像是一个超级用户的问题。
@Adrian: echo "alias sudo='sudo -E'" >>~/.bashrc
谢谢！我把它放在~/.profile，因为我没有.bashrc。