It's an external command for Homebrew. It provides installation caveat descriptions for Homebrew packages and casks.
Although the script's names is brew-caveats.rb, Homebrew external
commands work in such a way that you invoke them as brew caveats. (It
functions exactly like a sub-command built into Homebrew.)
If you already know the name of a package, and you want to see a bit about it, that's easy:
$ brew caveats zsh redis mysql
==> zsh: Caveats
Add the following to your zshrc to access the online help:
unalias run-help
autoload run-help
HELPDIR=/usr/local/share/zsh/helpfiles
==> redis: Caveats
To have launchd start redis now and restart at login:
brew services start redis
Or, if you don't want/need a background service you can just run:
redis-server /usr/local/etc/redis.conf
==> mysql: Caveats
We've installed your MySQL database without a root password. To secure it run:
mysql_secure_installation
To connect run:
mysql -uroot
To have launchd start mysql now and restart at login:
brew services start mysql
Or, if you don't want/need a background service you can just run:
mysql.server start
This is also valid for casks:
$ brew caveats osxfuse anaconda
==> osxfuse: Caveats
To install and/or use osxfuse you may need to enable their kernel extension in
System Preferences → Security & Privacy → General
For more information refer to vendor documentation or the Apple Technical Note:
https://developer.apple.com/library/content/technotes/tn2459/_index.html
You must reboot for the installation of osxfuse to take effect.
==> anaconda: Caveats
To use anaconda, you may need to add the /usr/local/anaconda3/bin directory to your PATH environment variable, eg (for bash shell):
export PATH=/usr/local/anaconda3/bin:"$PATH"
Cask anaconda installs files under /usr/local. The presence of such files can cause warnings when running "brew doctor", which is considered to be a bug in Homebrew Cask.
You can install brew caveats with the following:
brew tap rafaelgarrido/homebrew-caveats
Once you've installed you can use the commands as described above.