How to reset anything related to Ruby to factory settings on Mac OS High Sierra

I would close & reopen your terminal window before you start all of this to make sure you don't have any old env vars loaded.

General things:

• Run env | grep RUBY, env | grep RVM and look for any leftover environment variables that you may have set
• Same for env | grep GEM. Sometimes you'll see GEM_PATH, GEM_HOME, etc. but these aren't necessary for system ruby
• Peek inside your ~/.bash_profile, ~/.bashrc, and ~/.profile files and see if you've added any rvm stuff

If you're running macOS Mojave (I'm comparing against my system):

which ruby should return /usr/bin/ruby. If it doesn't, you have something else interfering. Post what that is and we can get it fixed.

Running /usr/bin/ruby --version should return ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin18]

Permissions for system ruby:

-r-xr-xr-x  1 root  wheel  52016 Nov 30 02:38 /usr/bin/ruby

This should be something like sudo chmod 555 /usr/bin/ruby to fix this if yours is difference. If you have different owners you'll need to sudo chown root:wheel /usr/bin/ruby

You'll also want to check which gem, and see if it reports /usr/bin/gem. Permissions should be the same as /usr/bin/ruby. /usr/bin/gem --version should return 2.5.2.3

Running /usr/bin/gem env should return something similar-ish to below. Replace jay (my computer user) with yours

RubyGems Environment:
  - RUBYGEMS VERSION: 2.5.2.3
  - 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/jay/.gem/ruby/2.3.0 # this doesn't matter much
  - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/local/bin
  - SPEC CACHE DIRECTORY: /Users/jay/.gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /Library/Ruby/Site
  - RUBYGEMS PLATFORMS:
    - ruby
    - universal-darwin-18
  - GEM PATHS:
     - /Library/Ruby/Gems/2.3.0
     - /Users/jay/.gem/ruby/2.3.0
     - /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/gems/2.3.0
  - GEM CONFIGURATION:
     - :update_sources => false
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
     - :sources => ["https://rubygems.org/"]
     - "benchmark" => true
     - "gem" => "--document=yri"
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /usr/local/bin
     - /Users/jay/bin
     - /usr/local/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /opt/X11/bin

From there you've got two directories you probably want to look at:

Run ls -al /Library/Ruby/. You should see this:

drwxr-xr-x   3 root  wheel    96 Aug 17 18:59 Gems
drwxr-xr-x   3 root  wheel    96 Aug 17 18:59 Site

You may need to chmod/chown each of those directories (with -R for recursive)

When you're done, please note that running /usr/bin/gem install bundler and gem install bundler (assuming you haven't installed a new ruby version manager) should yield an error as below (this means you re-configured the permissions correctly).

Fetching: bundler-1.17.2.gem (100%)
ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /Library/Ruby/Gems/2.3.0 directory.

You'll see some tutorials mention changing those permissions, or running sudo to install gems but I don't recommend that. My favorite ruby version manager is asdf which may be worth a look. You'll install the core, and the ruby plugin.

This should get you a little bit closer. If you see anything else messed up, please post the error.

rm -rf ~/.rvm, then edit ~/.bash_profile to remove source $HOME/.rvm/scripts/rvm.

Then you can restart with RVM from scratch by following the detailed installation instructions at https://rvm.io/rvm/install.