A bash script that adds a mysql user, and creates a database with the same name as the user and echos the generated password

addmysqluser.sh

#!/bin/bash
#By Nate Flink
                                                             
# Adds a mysql user, and creates a database with the same name as the user and echos the generated password

if [ -z "$1" ] || [ -z "$2" ] || [ -z "$3" ]; then
  echo "Usage: ./$0 [mysql db username] [mysql user password] [new identifier] [optional password]"
  exit 1
fi

DB_PASSWORD=$(env LC_CTYPE=C tr -dc "a-zA-Z0-9-_\$\?" < /dev/urandom | head -c 16)
DB_USER=$3

if [ -n "$4" ]; then
  DB_PASSWORD=$4
fi


#sql for creating a user and a database
CMD=$(cat <<EOF 
CREATE USER '$DB_USER'@'%' IDENTIFIED BY '$DB_PASSWORD';
GRANT USAGE ON * . * TO '$DB_USER'@'%' IDENTIFIED BY '$DB_PASSWORD' WITH MAX_QUERIES_PER_HOUR 0 MAX_CONNECTIONS_PER_HOUR 0 MAX_UPDATES_PER_HOUR 0 MAX_USER_CONNECTIONS 0;
CREATE DATABASE IF NOT EXISTS \`$DB_USER\`;
GRANT ALL PRIVILEGES ON \`$DB_USER\` . * TO '$DB_USER'@'%';
EOF
)

mysql -u "$1" -p"$2" -e "$CMD"
echo "$DB_PASSWORD"
exit 0