Gem macOS Mojave /Library/Ruby/Gems 下有多个版本的目录，是否可以安全删除？
请问社区里面的大大，我这种情况该如何解决？问题是这样的：
我现在的系统 /Library/Ruby/Gems 目录下有两个版本的 gems 目录，分别为 2.0.0，2.3.0，但是从 gem list 命令来看，只有 2.3.0 下面的是有效的，现在我想直接删除 2.0.0 下面的 gems，但是不知道直接删除是否安全，所以求助大家。我磁盘空间有限，想清理一下。
我试过 gem cleanup，没有任何效果，输出如下：
➜ Gems gem cleanup
Cleaning up installed gems...
Clean up complete
gem 的相关环境信息：
➜ Gems pwd
/Library/Ruby/Gems
➜ Gems ls -l
total 0
drwxr-xr-x 7 root wheel 224 Sep 25 13:31 2.0.0
drwxr-xr-x 8 root wheel 256 Aug 18 06:59 2.3.0
➜ Gems ruby -v
ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin18]
➜ Gems which ruby
/usr/bin/ruby
➜ Gems gem environment
RubyGems Environment:
- RUBYGEMS VERSION: 2.7.7
- RUBY VERSION: 2.3.7 (2018-03-28 patchlevel 456) [universal.x86_64-darwin18]
- INSTALLATION DIRECTORY: /Library/Ruby/Gems/2.3.0
- USER INSTALLATION DIRECTORY: /Users/mutsu/.gem/ruby/2.3.0
- RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby
- EXECUTABLE DIRECTORY: /usr/bin
- SPEC CACHE DIRECTORY: /Users/mutsu/.gem/specs
- SYSTEM CONFIGURATION DIRECTORY: /Library/Ruby/Site
- RUBYGEMS PLATFORMS:
- ruby
- universal-darwin-18
- GEM PATHS:
- /Library/Ruby/Gems/2.3.0
- /Users/mutsu/.gem/ruby/2.3.0
- /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/gems/2.3.0
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- :sources => ["https://gems.ruby-china.com"]
- REMOTE SOURCES:
- https://gems.ruby-china.com
- SHELL PATH:
- /usr/local/opt/curl/bin
- /usr/local/opt/openssl/bin
- /Users/mutsu/bin
- /usr/local/bin
- /usr/local/bin
- /usr/bin
- /bin
- /usr/sbin
- /sbin
gem list 命令只列出了 /Library/Ruby/Gems/2.3.0下面的gems，
➜ Gems gem list
*** LOCAL GEMS ***
activesupport (4.2.11)
atomos (0.1.3)
bigdecimal (default: 1.2.8)
CFPropertyList (3.0.0, 2.2.8)
claide (1.0.2)
cocoapods (1.5.3)
cocoapods-core (1.5.3)
cocoapods-deintegrate (1.0.2)
cocoapods-downloader (1.2.2)
cocoapods-plugins (1.0.0)
cocoapods-search (1.0.0)
cocoapods-stats (1.0.0)
cocoapods-trunk (1.3.1)
cocoapods-try (1.1.0)
colored2 (3.1.2)
concurrent-ruby (1.1.3)
did_you_mean (1.0.0)
escape (0.0.4)
fourflusher (2.0.1)
fuzzy_match (2.0.4)
gh_inspector (1.1.3)
i18n (0.9.5)
io-console (default: 0.4.5)
json (default: 1.8.3.1)
libxml-ruby (2.9.0)
minitest (5.8.5)
molinillo (0.6.6)
nanaimo (0.2.6)
nap (1.1.0)
net-telnet (0.1.1)
netrc (0.11.0)
nokogiri (1.5.6)
power_assert (0.2.6)
psych (default: 2.1.0.1)
rake (10.4.2)
rdoc (default: 4.2.1)
rouge (2.0.7)
ruby-macho (1.3.1)
rubygems-update (2.7.7)
sqlite3 (1.3.11)
test-unit (3.1.5)
thread_safe (0.3.6)
tzinfo (1.2.5)
xcodeproj (1.7.0)
xcpretty (0.3.0)
2.3.0 目录下面的已安装 gems
➜ Gems ls 2.3.0/gems
CFPropertyList-3.0.0 cocoapods-downloader-1.2.2 concurrent-ruby-1.1.3 minitest-5.8.5 rake-10.4.2 tzinfo-1.2.5
activesupport-4.2.11 cocoapods-plugins-1.0.0 did_you_mean-1.0.0 molinillo-0.6.6 rdoc-4.2.1 xcodeproj-1.7.0
atomos-0.1.3 cocoapods-search-1.0.0 escape-0.0.4 nanaimo-0.2.6 rouge-2.0.7 xcpretty-0.3.0
claide-1.0.2 cocoapods-stats-1.0.0 fourflusher-2.0.1 nap-1.1.0 ruby-macho-1.3.1
cocoapods-1.5.3 cocoapods-trunk-1.3.1 fuzzy_match-2.0.4 net-telnet-0.1.1 rubygems-update-2.7.7
cocoapods-core-1.5.3 cocoapods-try-1.1.0 gh_inspector-1.1.3 netrc-0.11.0 test-unit-3.1.5
cocoapods-deintegrate-1.0.2 colored2-3.1.2 i18n-0.9.5 power_assert-0.2.6 thread_safe-0.3.6
2.0.0 目录下面的已安装 gems
➜ Gems ls 2.0.0/gems
RedCloth-4.2.9 cocoapods-downloader-1.1.0 execjs-2.4.0 liquid-2.6.2 redcarpet-3.2.2
activesupport-4.2.1 cocoapods-plugins-0.4.2 fast-stemmer-1.0.2 listen-2.9.0 rouge-1.11.1
addressable-2.3.7 cocoapods-plugins-1.0.0 fastimage-1.6.8 mercenary-0.3.5 rubygems-update-2.5.1
blankslate-2.1.2.4 cocoapods-plugins-1.0.0.beta.1 ffi-1.9.8 mini_portile-0.6.2 rubygems-update-2.6.7
bundler-1.9.1 cocoapods-search-0.1.0 fourflusher-0.3.2 minitest-5.5.1 safe_yaml-1.0.4
celluloid-0.16.0 cocoapods-search-1.0.0 fui-0.4.0 molinillo-0.3.1 sass-3.4.13
claide-0.9.1 cocoapods-search-1.0.0.beta.1 fuzzy_match-2.0.4 molinillo-0.4.1 term-ansicolor-1.3.2
claide-1.0.0 cocoapods-stats-0.5.3 gemoji-2.1.0 molinillo-0.4.5 thor-0.19.1
claide-1.0.0.beta.1 cocoapods-stats-0.6.2 github-pages-health-check-0.2.2 nap-0.8.0 thread_safe-0.3.5
classifier-reborn-2.0.3 cocoapods-stats-1.0.0 gli-2.14.0 nap-1.0.0 timers-4.0.1
cocoa-0.1.6 cocoapods-stats-1.0.0.beta.3 hitimes-1.2.2 net-dns-0.8.0 tins-1.12.0
cocoapods-0.38.0 cocoapods-trunk-0.6.4 i18n-0.7.0 netrc-0.7.8 toml-0.1.2
cocoapods-0.38.2 cocoapods-trunk-1.0.0 inquirer-0.2.1 nokogiri-1.6.6.2 tzinfo-1.2.2
cocoapods-1.0.0 cocoapods-trunk-1.0.0.beta.1 jekyll-2.4.0 parslet-1.5.0 update_xcode_plugins-0.3.1
cocoapods-1.0.1 cocoapods-try-0.4.5 jekyll-2.5.3 pods-0.0.1 update_xcode_plugins-0.3.2
cocoapods-core-0.38.0 cocoapods-try-0.5.1 jekyll-coffeescript-1.0.1 posix-spawn-0.3.10 xcodeproj-0.26.3
cocoapods-core-0.38.2 cocoapods-try-1.0.0.beta.2 jekyll-gist-1.2.1 public_suffix-1.4.6 xcodeproj-0.28.2
cocoapods-core-0.39.0 cocoapods-try-1.1.0 jekyll-paginate-1.1.0 pygments.rb-0.6.1 xcodeproj-1.0.0.beta.2
cocoapods-core-1.0.0 coffee-script-2.3.0 jekyll-sass-converter-1.2.0 pygments.rb-0.6.2 xcodeproj-1.2.0
cocoapods-core-1.0.0.beta.2 coffee-script-source-1.9.1 jekyll-sass-converter-1.3.0 rack-1.6.5 xcpretty-0.2.4
cocoapods-core-1.0.1 colorator-0.1 jekyll-watch-1.2.1 rack-http-logger-0.1.0 yajl-ruby-1.2.1
cocoapods-deintegrate-1.0.0 colored-1.2 json-1.8.2 rake-10.4.2
cocoapods-deintegrate-1.0.0.beta.1 colorize-0.8.1 kramdown-1.5.0 rb-fsevent-0.9.4
cocoapods-downloader-0.9.3 earlgrey-0.0.8 kramdown-1.6.0 rb-inotify-0.9.5
cocoapods-downloader-1.0.0.beta.1 escape-0.0.4 liquid-2.6.1 redcarpet-3.1.2
pynix
#1
2018年12月01日
/usr/bin/ruby -v ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin18]
10.14 好像升级到 2.3，但是也很落后了。。。
可以直接删掉，一般 /System/Library/Frameworks/Ruby.framework/Versions 也不留老的，那这些 gem 也没用了