MySQL: Find the path to the my.cnf configuration file

# 方式一
ps -ef|grep mysql|grep 'my.cnf'

# 方式二
mysql --help|grep 'my.cnf'

# 方式三
find / -name my.cnf

default search path

/etc/my.cnf 
/etc/mysql/my.cnf 
/usr/local/etc/my.cnf 
~/.my.cnf

Refer to
MySQL to view the currently used configuration file my.cnf method