Can't properly set MySQL password from externa

I have two scripts - The main one that does a few different things and calls the second script, and the second script that installs MySQL.

From my main script I do something like this:

...

read -p "Set the password for the database [min. 4 characters]: " MPASS

# Install MySQL
path/to/setup-mysql.sh "$MPASS"

mysql --user="root" --password=${MPASS} -e "GRANT ALL ON *.* TO root@'${IPADDRESS}' IDENTIFIED BY '${MPASS}';"
mysql --user="root" --password=${MPASS} -e "GRANT ALL ON *.* TO root@'%' IDENTIFIED BY '${MPASS}';"
service mysql restart

mysql --user="root" --password=${MPASS} -e "SET GLOBAL validate_password_policy = 'LOW'; SET GLOBAL validate_password_length = 4; CREATE USER 'johndoe'@'${IPADDRESS}' IDENTIFIED BY '${MPASS}';"
mysql --user="root" --password=${MPASS} -e "GRANT ALL ON *.* TO 'johndoe'@'${IPADDRESS}' IDENTIFIED BY '${MPASS}' WITH GRANT OPTION;"
mysql --user="root" --password=${MPASS} -e "GRANT ALL ON *.* TO 'johndoe'@'%' IDENTIFIED BY '${MPASS}' WITH GRANT OPTION;"
mysql --user="root" --password=${MPASS} -e "FLUSH PRIVILEGES;"

And setup-mysql.sh looks like this:

#!/bin/bash

export DEBIAN_FRONTEND=noninteractive

debconf-set-selections <<< "mysql-community-server mysql-community-server/data-dir select ''"
debconf-set-selections <<< "mysql-community-server mysql-community-server/root-pass password ${1}"
debconf-set-selections <<< "mysql-community-server mysql-community-server/re-root-pass password ${1}"

apt-get install -y mysql-server

# Start mysql on boot
update-rc.d mysql defaults

# Configure Password Expiration
echo "default_password_lifetime = 0" >> /etc/mysql/my.cnf

# Configure Access Permissions For Root
sed -i '/^bind-address/s/bind-address.*=.*/bind-address = */' /etc/mysql/my.cnf

To me this looks like it should work, however, when bash executes this line:

mysql --user="root" --password=${MPASS} -e "GRANT ALL ON *.* TO root@'${IPADDRESS}' IDENTIFIED BY '${MPASS}';"

It says that the password is wrong. When I try logging in manually it wont work. And when I skip the password field (mysql -u root) it works. So the password is not being set at all.

Also, when I do echo $1 in setup-mysql.sh, it properly shows what MPASS contains.

Why isn't debconf-set-selections setting the password properly for my MySQL installation. I'm really confused here.

It seems that you are writing a MySQL post-installation initialization shell script.

In my personal opinion: change your shell script design method.

In your script, you use mysql --user="root" --password=${MPASS} prompt error info. You could use mysql paramater --defaults-file, write mysql login user root and corresponding password into a temp file like

[client]
user=root
password=YOURPASSWORD

suppose file path is /tmp/mysql.cnf (assign variable mysql_my_cnf)

Then use mysql --defaults-file="$mysql_my_cnf" login, it will login successfully.

Assign a variable to mysql --defaults-file="$mysql_my_cnf", such as mysql_command

Old method

mysql --user="root" --password=${MPASS} -e "GRANT ALL ON *.* TO root@'${IPADDRESS}' IDENTIFIED BY '${MPASS}';"

New method

${mysql_command} -e "GRANT ALL ON *.* TO root@'${IPADDRESS}' IDENTIFIED BY '${MPASS}';"

You can try it.

PS

I wrote a MySQL and its variants installation and initialization shell script, it may be helpful for you.