Uninstalling MariaDB/MySQL on CentOS 7 or RHEL 7: A Step-by-Step Guide

• mysql: This refers to the database management system itself, not a programming instruction.
• centos: This isn't part of the commands, it's the operating system (CentOS 7 or RHEL 7) where these commands are used.
• mariadb: This is also not a programming instruction, it refers to the specific database software being removed.

The commands used are likely yum commands, specific to RHEL/CentOS package management:

1. sudo yum remove mariadb mariadb-server: This command removes two packages: mariadb (the core database libraries) and mariadb-server (the actual MariaDB server process).
2. rm -rf /var/lib/mysql: This command (use with caution!) forcefully removes the directory /var/lib/mysql. This directory typically holds the database files. Be aware that this will erase your data unless you have backed it up beforehand.

Optional Steps:

• rm /etc/my.cnf: This removes the main configuration file for MariaDB. This might be automatically removed in step 1 depending on the system.
• rm ~/.my.cnf: This removes any local user configuration for MariaDB (~ refers to the current user's home directory).

# Uninstall MariaDB packages
sudo yum remove mariadb mariadb-server

# Optionally remove data directory (use with caution!)
sudo rm -rf /var/lib/mysql

# Optionally remove configuration files (might be done automatically)
sudo rm /etc/my.cnf
rm ~/.my.cnf

Explanation:

1. sudo yum remove mariadb mariadb-server: This line removes the mariadb package (core database libraries) and the mariadb-server package (the actual MariaDB server process) using yum, the package manager for CentOS/RHEL.
2. sudo rm -rf /var/lib/mysql: This line forcefully removes the directory /var/lib/mysql, which typically holds the database files. Use this command with extreme caution! It will permanently erase your data unless you have a backup. Make sure you have a backup before proceeding.
3. rm ~/.my.cnf: This line removes any local user configuration for MariaDB from the current user's home directory (~ represents the home directory).

Important Notes:

• Always back up your data before running rm -rf /var/lib/mysql to avoid permanent data loss.
• Consider using a more granular approach for removing specific configuration files instead of deleting ~/.my.cnf entirely.
• These commands are specific to CentOS/RHEL 7. The package names and locations might differ on other systems.

While not necessarily an alternative method, you can use the -y flag with yum remove to bypass confirmation prompts:

sudo yum remove -y mariadb mariadb-server

This is useful when you're confident about the removal and don't need confirmation for each package.

Scripting the removal process:

You can create a shell script that automates the removal process. This can be helpful if you need to perform this task repeatedly on different machines. Here's an example script:

#!/bin/bash

# Remove MariaDB packages
sudo yum remove mariadb mariadb-server

# Optionally remove data directory (use with caution!)
# Comment out this line if you want to keep data
# sudo rm -rf /var/lib/mysql

# Optionally remove configuration files (might be done automatically)
sudo rm /etc/my.cnf
rm ~/.my.cnf

echo "MariaDB removal complete!"

Using dnf (package manager for newer RHEL/CentOS):

If you're using a newer version of RHEL/CentOS (8 or later), the package manager is dnf instead of yum. The commands would be similar, but replacing yum with dnf:

sudo dnf remove mariadb mariadb-server

Important considerations for all methods:

• Data backup: Always back up your data before running any removal commands, especially those involving rm -rf.
• Granular configuration removal: Instead of deleting ~/.my.cnf entirely, consider identifying specific configuration files you want to remove based on your needs.