How Do I Change The Default Character Set in MySQL/MariaDB to utf8?

Introduction

How do I change the default Character set within MySQL/MariaDB to utf8? 

Procedure

In order to set change the default character set within MySQL/MariaDB follow the steps below: 

Open the MySQL configuration file at /etc/my.cnf: 

vi /etc/my.cnf

Under the [client] section, add the following entry: 

default-character-set=utf8

Under [mysqld] add: 

default-character-set=utf8
init_connect=’SET NAMES utf8′

Once complete, you'll need to issue a restart to the MySQL server: 

/scripts/restartsrv_mysql

If you would like to validate that the changes have been applied, you may pass the following command via MySQL CLI: 

show variables like ‘char%';

Please note that existing databases are not affected unless you alter their character sets. You can review MySQL documentation on this topic for more information on how this works:

MySQL :: MySQL 5.6 Reference Manual :: 10.5 Character Set Configuration
MySQL :: MySQL 5.6 Reference Manual :: 10.1.3.3 Database Character Set and Collation

MariaDB also provides a useful document on setting the character set for your databases:

Setting Character Sets and Collations