Mysql restore empty root password after update

mysql-restore-root.sh

#!/bin/bash

function log {
  echo $@
}

function stop_mysql_server {
  log 'Stopping'
  sleep 2
  sudo /etc/init.d/mysql stop
  sleep 2
  sudo killall mysqld_safe
  sleep 2
  sudo killall mysqld
  sleep 2
}

function mkdir_sock_mysql {
  log 'Make dir /var/run/mysqld'
  sudo mkdir -p /var/run/mysqld
  sudo chown mysql. -R /var/run/mysqld
  sudo chmod 0755 /var/run/mysqld
  sleep 1
}

function start_mysql_skip_grant {
  log 'Start skip grant'
  sudo mysqld_safe --skip-grant-tables &
  sleep 5
}

function exec_query {
  log $@
  mysql -u root mysql -e "$@"
}

function start_mysql {
  log 'Start mysql'
  sudo /etc/init.d/mysql start
}

stop_mysql_server
mkdir_sock_mysql
start_mysql_skip_grant
exec_query "update user set authentication_string=PASSWORD('') where User='root'; update user set plugin='mysql_native_password';"
stop_mysql_server
start_mysql