a.rb

$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry and just ignore them. Thanks!

Warning: You have unlinked kegs in your Cellar
Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
  [email protected]
  llvm37-julia
  llvm39-julia
  metis

$ brew config
HOMEBREW_VERSION: 1.3.2-65-gc0063bb-dirty
ORIGIN: https://github.com/Homebrew/brew
HEAD: c0063bb827ffa9cd537a0ca107aa05ca1323393c
Last commit: 12 hours ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: c26042c9ba11f261523630a7860d90c4c64ef6a1
Core tap last commit: 9 minutes ago
HOMEBREW_PREFIX: /usr/local
HOMEBREW_REPOSITORY: /usr/local/Homebrew
HOMEBREW_CELLAR: /usr/local/Cellar
HOMEBREW_BOTTLE_DOMAIN: https://homebrew.bintray.com
CPU: octa-core 64-bit kabylake
Homebrew Ruby: 2.0.0-p648
Clang: 8.1 build 802
Git: 2.13.2 => /usr/local/bin/git
Perl: /usr/local/bin/perl => /usr/local/Cellar/perl/5.26.0/bin/perl
Python: /usr/bin/python
Ruby: /usr/local/bin/ruby => /usr/local/Cellar/ruby/2.4.1_1/bin/ruby
Java: 1.8.0_141
macOS: 10.12.6-x86_64
Xcode: N/A
CLT: 8.3.2.0.1.1492020469
X11: 2.7.11 => /opt/X11