For homebrew mysql installs, where\'s my.cnf? Does it install one?
Since mysql --help shows a list of files, I find it useful to pipe the result to ls to see which of them exist:
$ mysql --help | grep /my.cnf | xargs ls
ls: /etc/my.cnf: No such file or directory
ls: /etc/mysql/my.cnf: No such file or directory
ls: ~/.my.cnf: No such file or directory
/usr/local/etc/my.cnf
For my (Homebrew installed) MySQL 5.7, it seems the files is on /usr/local/etc/my.cnf.