これが一番いろいろ分かって便利です。 gem environmentの実行結果はこんな感じ。 RubyGems Environment: - RUBYGEMS VERSION: 1.0.1 (1.0.1) - RUBY VERSION: 1.8.6 (2007-12-09 patchlevel 5000) [i686-darwin8.11.1] - INSTALLATION DIRECTORY: /usr/local/ruby/lib/ruby/gems/1.8 - RUBY EXECUTABLE: /usr/local/ruby/bin/ruby - RUBYGEMS PLATFORMS: - ruby - x86-darwin-8 - GEM PATHS: - /usr/local/ruby/lib/ruby/gems/1.8 - GEM CONFIGURATION: - :upda