<RubyGems> How to change gem environment settings?

I installed `rbenv` and set up ruby and gems. Now if I run `gem env` then I got the following:

RubyGems Environment:
- RUBYGEMS VERSION: 2.2.2
- RUBY VERSION: 2.1.0 (2013-12-25 patchlevel 0) [x86_64-darwin13.0]
- INSTALLATION DIRECTORY: /Users/myusername/Tools/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0
- RUBY EXECUTABLE: /Users/myusername/Tools/.rbenv/versions/2.1.0/bin/ruby
- EXECUTABLE DIRECTORY: /Users/myusername/Tools/.rbenv/versions/2.1.0/bin
- SPEC CACHE DIRECTORY: /Users/myusername/.gem/specs
- RUBYGEMS PLATFORMS:
- ruby
- x86_64-darwin-13
- GEM PATHS:
- /Users/myusername/Tools/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0
- /Users/myusername/.gem/ruby/2.1.0
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
-

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- SHELL PATH:
- /Users/myusername/Tools/.rbenv/versions/2.1.0/bin
- /Users/myusername/Tools/.rbenv/libexec
- /Users/myusername/Tools/.rbenv/plugins/ruby-build/bin
- /opt/local/bin
- /opt/local/sbin
- /Users/myusername/Tools/.rbenv/shims
- /usr/bin
- /bin
- /usr/sbin
- /sbin
- /usr/local/bin
- /Users/myusername/Tools/./bin
- /Users/myusername/Tools/.rbenv/bin

Well.. all looks good except for `SPEC CACHE DIRECTORY` and `GEM PATHS`, all others have self-configured paths. (So I really don't want any dev-related directories directly placed in my user home folder.) Is there a way to flexibly change these two `env variables` without affecting normal functioning of `ruby`, `gem` and `rbenv` etc.?

Thanks!

Actually I searched online and found the solution.

Just put the following in your .profile (Max OS) or .bashrc (Linux)

export GEM_PATH=/Users/myusername/Tools/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0
export GEM_SPEC_CACHE=/Users/myusername/Tools/.rbenv/versions/2.1.0/lib/ruby/gems/specs

Make sure the folder you put there existed. Then source the .profile or .bashrc, or simply restart your terminal. It is tested working now my env is correct.

Reference:

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