rvm use rbx (rm all dirs)

-=>> which irb
/Users/cheba/.rvm/rubies/rbx-head/bin/irb
-=>> which gem
/Users/cheba/.rvm/rubies/rbx-head/bin/gem
-=>> echo $GEM_PATH
/Users/cheba/.rvm/gems/rbx-head:/Users/cheba/.rvm/gems/rbx-head@global
-=>> echo $GEM_HOME
/Users/cheba/.rvm/gems/rbx-head
-=>> which gem
/Users/cheba/.rvm/rubies/rbx-head/bin/gem
-=>> gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 2.1.4
  - RUBY VERSION: 2.1.0 (2013-09-23 patchlevel 0) [x86_64-darwin12.5.0]
  - INSTALLATION DIRECTORY: /Users/cheba/.rvm/gems/rbx-head
  - RUBYGEMS PREFIX: /Users/cheba/.rvm/rubies/rbx-head
  - RUBY EXECUTABLE: /Users/cheba/.rvm/rubies/rbx-head/bin/rbx
  - EXECUTABLE DIRECTORY: /Users/cheba/.rvm/gems/rbx-head/bin
  - SPEC CACHE DIRECTORY: /Users/cheba/.gem/specs
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-darwin-12
    - x86_64-rubinius-2.1
  - GEM PATHS:
     - /Users/cheba/.rvm/gems/rbx-head
     - /Users/cheba/.rvm/gems/rbx-head@global
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /Users/cheba/.rvm/gems/rbx-head/bin
     - /Users/cheba/.rvm/gems/rbx-head@global/bin
     - /Users/cheba/.rvm/rubies/rbx-head/bin
     - /Users/cheba/.rvm/bin
     - /Users/cheba/.bash/bin
     - /usr/local/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /opt/X11/bin
     - /usr/local/MacGPG2/bin
     - /usr/texbin
-=>> gem i --backtrace rubysl
ERROR:  While executing gem ... (RuntimeError)
    can't modify frozen object
  kernel/common/marshal.rb:549:in `construct'
	kernel/common/marshal.rb:585:in `construct_array'
	kernel/common/integer.rb:194:in `times'
	kernel/common/marshal.rb:584:in `construct_array'
	kernel/common/marshal.rb:488:in `construct'
	kernel/common/marshal.rb:1176:in `load'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/specification.rb:1134:in `_load'
	kernel/common/marshal.rb:805:in `construct_user_defined'
	kernel/common/marshal.rb:498:in `construct'
	kernel/common/marshal.rb:1176:in `load'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/source.rb:108:in `fetch_spec'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver/installer_set.rb:124:in `load_spec'
	kernel/common/hash.rb:356:in `fetch'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver/installer_set.rb:121:in `load_spec'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver/index_specification.rb:56:in `spec'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver/index_specification.rb:28:in `dependencies'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver.rb:63:in `requests'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver.rb:161:in `resolve_for'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver.rb:194:in `resolve_for'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver.rb:194:in `resolve_for'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_resolver.rb:87:in `resolve'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/request_set.rb:134:in `resolve'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_installer.rb:412:in `resolve_dependencies'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/dependency_installer.rb:351:in `install'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/commands/install_command.rb:180:in `install_gem'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/commands/install_command.rb:194:in `install_gems'
	kernel/bootstrap/array.rb:66:in `each'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/commands/install_command.rb:190:in `install_gems'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/commands/install_command.rb:146:in `execute'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/command.rb:305:in `invoke_with_build_args'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/command_manager.rb:167:in `process_args'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/command_manager.rb:137:in `run'
	/Users/cheba/.rvm/rubies/rbx-head/lib/rubygems/gem_runner.rb:54:in `run'
	/Users/cheba/.rvm/rubies/rbx-head/lib/bin/gem.rb:21:in `__script__'
	kernel/delta/codeloader.rb:66:in `load_script'
	kernel/delta/codeloader.rb:109:in `load_script'
	kernel/loader.rb:643:in `script'
	kernel/loader.rb:834:in `main'

rvm use system

-=>> which irb
/usr/bin/irb
-=>> which gem
/usr/bin/gem
-=>> echo $GEM_PATH

-=>> echo $GEM_HOME

-=>> which gem
/usr/bin/gem
-=>> gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 1.3.6
  - RUBY VERSION: 1.8.7 (2012-02-08 patchlevel 358) [universal-darwin12.0]
  - INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8
  - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - universal-darwin-12
  - GEM PATHS:
     - /Library/Ruby/Gems/1.8
     - /Users/cheba/.gem/ruby/1.8
     - /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://rubygems.org/