iandark

// 1 - Edit your my.cnf
$ sudo nano /etc/mysql/my.cnf

// 2 - In your my.cnf, add this to section [mysqld], if your file doesn't have this section you should create
[mysqld]
validate_password.length = 4
validate_password.policy = low
validate_password.mixed_case_count = 0
validate_password.number_count = 0
validate_password.special_char_count = 0

iandark

// 1 - Enter in mysql console
$ mysql -u root

// 1.1 (optional) - if you can't login into mysql console add this in [mysqld] section in your my.cnf file (/etc/mysql/my.cnf): 
skip-grant-tables

// 2 - See your password strength
mysql> SHOW VARIABLES LIKE 'validate_password%';

// your output will be something like this: