uninstall mysql 5.4 and install mariadb on centos code example

Example 1: uninstall mariadb server and client in ubuntu 18.4

sudo systemctl stop mysql
sudo apt-get remove --purge mysql-server mysql-client mysql-common

Example 2: uninstall mariadb server and client in ubuntu 18.4

sudo apt-get autoclean
sudo rm -rf /var/lib/mysql/
sudo rm -rf /etc/mysql/