There is no internal MySQL command to trace this, it’s a little too abstract. The file might be in 5 (or more?) locations, and they would all be valid because they load cascading.
Those are the default locations MySQL looks at. If it finds more than one, it will load each of them & values override each other (in the listed order, I think). Also, the
--defaults-file parameter can override the whole thing, so… basically, it’s a huge pain in the butt.
But thanks to it being so confusing, there’s a good chance it’s just in /etc/my.cnf.
(If you just want to see the values:
SHOW VARIABLES, but you’ll need the permissions to do so.)
mysql --help and you will see:
Default options are read from the following files in the given order: /etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf