MySQL root user password change automation

Question

folks,

I am trying to automate MySQL root user user temporary password change.

Details:

OS Centos7, mysql Ver 8.0.19-10 for Linux on x86_64 (Percona Server (GPL), Release 10, Revision f446c04)

My script:

#!/bin/sh
PSW=$1
MYPASS = `grep 'temporary password' /var/log/mysqld.log|awk '{print $13}'`
echo $MYPASS
sleep 3
echo "ALTER USER 'root'@'localhost' IDENTIFIED WITH   mysql_native_password BY '$PSW';" >> /root/my.sql
echo "GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION;" >> /root/my.sql
sleep 3
mysql --connect-expired-password -u root --password='$MYPASS' mysql < /root/my.sql
sleep 5                    

Script's logic

I execute a script which is called prepare_db.sh from shell with a command and pass PSW variable (want to change temp psw to this one)

sh prepare_db.sh Pass123

it grabs temp mysql root psw assigns it to a variable MYPASS creates my.sql file which looks like that:

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'Pass123';
GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION;

when sql file is created script automatically tries to execute it with a command:

mysql --connect-expired-password -u root --password='$MYPASS' mysql < /root/my.sql

Problem

Everytime I get an error saying that access is dennied:

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

Strange thing

If I try to run same command from a shell, I get no error and password changes..

mysql --connect-expired-password -u root --password='e=F4D4N7<-gp' mysql < /root/my.sql

Please help me to find a mistake, or a solution how could I achieve my goal - automate roots temp password reset

Thank you in advance!

Answer 1

The issue is that you are using single quotes in your command. With single quotes, variables are not expanded.

So, you are literally sending $MYPASS as password, instead of the contents of the MYPASS variable!

Change it to double quotes:

mysql --connect-expired-password -u root --password="$MYPASS" mysql < /root/my.sql

A tip for the future: If you (temporarily) add set -x at the start of your script, you'll see each line printed before it gets executed, after evaluation. This way you'd also have spotted that there is a literal $MYPASS .

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EDIT: As Cyrus mentioned in a comment , there is another issue to fix before this can work: Change /bin/sh to /bin/bash at the shebang of your script, and if you manually run it, use bash instead of sh .