A little script to creating database and user for application.

create_database_for_app.sh

#!/bin/bash
set -e

app_name=""
app_username=""
app_password="123456"
app_user_host="localhost"
db_name=""
mysql_username="root"
mysql_password=""

echo 
echo "#                                     "
echo "# Application Database Create Script  "
echo "#             For MySQL               "
echo "#                                     "
echo

input=""

#
# Asking mysql login token
#
password_field=""
read -p "Mysql username (Default is ${mysql_username}) : " input
[[ -z "${input}" ]] || mysql_username="${input}"
read -s -p "Mysql password (Default is empty) : " mysql_password && echo
[[ -z "$mysql_password" ]] || password_field="-p${mysql_password}"
mysql -u $mysql_username ${password_field} -e "select user,host from mysql.user where user='${mysql_user}';" --raw --batch 2> /dev/null > /dev/null || (echo "Login failed." && exit 1)
echo "Login success"

#
# Input database and user info
#
read -p "Application name?: " app_name 
[[ "${app_name}" =~ ^[0-9A-Za-z_\-]{3,16}$ ]] || ( echo "App name doesn't match pattern ^[0-9A-Za-z_\-]{3,16}$ " && exit 1 )
app_username="app_${app_name}"

read -p "Choose a username (Default is ${app_username}) : " input 
[[ -z "${input}" ]] || app_username="${input}"
[[ "${app_username}" =~ ^[0-9A-Za-z_\-]{3,16}$ ]] || ( echo "Username doesn't match pattern ^[0-9A-Za-z_\-]{3,16}$" && exit 1 )

read -p "User login scope? (Default is ${app_user_host}): " input 
[[ -z "${input}" ]] || app_user_host="${input}"
[[ "${app_user_host}" =~ ^[A-Za-z0-9.\-_]{1,32}$ ]] || ( echo "User host doesn't match pattern ^[A-Za-z0-9.\-_]{1,32}$" && exit 1 )
exists_user=$(mysql -u ${mysql_username} ${password_field} -e "select user,host from mysql.user where user = '${app_username}' and host = '${app_user_host}'" 2> /dev/null | awk 'NR > 1 { print $1 }')
[[ -z "${exists_user}" ]] || ( echo "User was exists" && exit 1 )

read -s -p "Choose a password (Default is ${app_password}) : " input && echo
[[ -z "${input}" ]] || (\
 app_password="${input}" &&\
 read -s -p "Confirm password: " input && echo &&\
 [[ "${input}" == "${app_password}" ]] || ( echo "Password not match." && exit 1 )\
)

db_name="db_${app_name}";
read -p "Database name? (Default is ${db_name}) : " input;
[[ -z "${input}" ]] || db_name="${input}";
[[ "${db_name}" =~ ^[0-9A-Za-z_\-]{3,16}$ ]] || ( echo "Database name not match pattern ^[0-9A-Za-z_\-]{3,16}$ " && exit 1 );
exists_db=$(mysql -u ${mysql_username} ${password_field} -e "show databases" --batch --raw 2> /dev/null | grep "${db_name}");
[[ -z "${exists_db}" ]] || ( echo "Database exists." && exit 1 );

echo "Create database and user for ${app_name}:"
echo "Username : ${app_username}"
echo "Hostname : ${app_user_host}"
echo "Password : ${app_password}"
echo "Database : ${db_name}"
read -p "Is that right?(Y/N):" input
[[ "${input}" =~ ^(yes|YES|Y|y)$ ]] || ( echo "Canceled." && exit 1 );

echo "Doing something ......"
mysql -u ${mysql_username} ${password_field} -e "\
create database ${db_name} charset utf8mb4;\
create user '${app_username}'@'${app_user_host}' identified by '${app_password}';\
grant all on ${db_name}.* to '${app_username}'@'${app_user_host}';\
flush privileges;\
" --batch --raw || ( echo "Crate database failed." && exit 1 )

echo "Create database successful"