A helpful Bash script to install Percona server on Ubuntu 16 - bash

Question

This is my first post.
I searched a lot and could not find all these pieces in one place. I gathered them from various posts on SO and managed to create a working script. All the credits go to their respective creators.
It's a bash script rather than a question.Hope it helps someone. Please feel free to suggest improvements.
#!/bin/bash
# Author: krishna - and thanks to all the helpful folks on SO.
# date: apr-03-2018
# script
# Notes: unattented script to install percona server. Pieced together from all over SO.
# see versions below next to each item. they are current as on this script creation dates.
# 2. percona server 5.7 or later
# 4. ubuntu 64bit 16.4.3
#
# This script works for me but may not be the best bash script, Please help, to make it better.
#
# you have to run this script as sudo
# if you saved this script as let's say install-percona.sh
# then do this
# chmod +x install-percona.sh
# sudo ./install-percona.sh
#
# do everything in downloads
mkdir -p ~/downloads
cd ~/downloads
# Variables
# Passwords are like under garments.
# 1. Dont leave them lying around
# 2. Change Often
# 3. Do not share it with others
# 4. Dont be chaep. Invest in STRONG AND high quality one's.
# So I hope you know what to do with the next 3 lines.
MYSQL_ROOT_PASSWORD="SecretRootPassword123"
DB_USERNAME="MickeyMouse"
DB_PASSWORD="SecretDBPassword123"
export DEBIAN_FRONTEND=noninteractive
sudo apt-get install -y debconf-utils
# Install software
# We are going to install Percona Server.
#
# By default, percona-server is going to ask for the root password and we automate that with debconf-set-selections
# begin percona stuff
# you need to change the next 2 lines, visit the percona server site to get latest values.
wget https://repo.percona.com/apt/percona-release_0.1-4.$(lsb_release -sc)_all.deb
dpkg -i percona-release_0.1-4.$(lsb_release -sc)_all.deb
#
apt-get update
# also change the version number accordingly. the -5.7 part
# Note. its root-pass and re-root-pass unlike root_password and root_password_again for other flavors of mysql.
#
# !!!!! CAUTION !!!!
# Be sure to check /var/cache/debconf/passwords.dat file for these 2 entries. After installation is completed.
# The value fields were clear in my case but check anyway.
# Y.M.M.V - dont want to leave passwords hanging in the clear.
#
#
echo "percona-server-server-5.7 percona-server-server-5.7/root-pass password ${MYSQL_ROOT_PASSWORD}" | debconf-set-selections
echo "percona-server-server-5.7 percona-server-server-5.7/re-root-pass password ${MYSQL_ROOT_PASSWORD}" | debconf-set-selections
apt install -y percona-server-server-5.7
# Configure MySQL ie Percona
# We are going to create a user also and the 3 CREATE FUNCTION lines are what percona suggests.
# these may happen silently
echo "lets configure percona."
mysql -u root -p${MYSQL_ROOT_PASSWORD} <<EOF
CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'libfnv1a_udf.so';
CREATE FUNCTION fnv_64 RETURNS INTEGER SONAME 'libfnv_udf.so';
CREATE FUNCTION murmur_hash RETURNS INTEGER SONAME 'libmurmur_udf.so';
CREATE USER '${DB_USERNAME}'#'localhost' IDENTIFIED BY '${DB_PASSWORD}';
GRANT ALL ON *.* TO '${DB_USERNAME}'#'localhost' with grant option;
FLUSH Privileges;
EOF
echo "make sure you run mysql_secure_installation after install"
# run the secure installation script
mysql_secure_installation
echo "done."