ubuntu 16 mysql 5.7 change root password

ubuntu16-mysql5.7-change-root-password.sh

#!/bin/bash

# this sctipt will change mysql root password in 3 seconds
# run it with one parameter - desired password

if [ -z "$1" ]
  then
    echo "Usage: $0 <new password>"
    exit 1
fi

# root is required for service restarts
if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root"
   exit 1
fi

# stop mysql process
echo "Stopping mysql process"
service mysql stop

sleep 1

# if not exists, create necessary directory for pid file
if [ ! -d "/var/run/mysqld" ]; then
   mkdir -p /var/run/mysqld
   chown mysql:mysql /var/run/mysqld
fi

# run mysqld_safe in background
echo "Running mysqld_safe in background"
mysqld_safe --skip-grant-tables &

# remember pid
pid=$!

# short pause to complete mysql initialization
sleep 5

# print users info before/after and change password for user root
mysql << END
   SELECT "Before:" AS '';
   SELECT User, authentication_string FROM mysql.user WHERE User='root';
   UPDATE mysql.user SET authentication_string=PASSWORD('$1') WHERE User='root';
   FLUSH PRIVILEGES;
   SELECT "After:" AS '';
   SELECT User, authentication_string FROM mysql.user WHERE User='root';
   SHUTDOWN;
END

# wait for process to stop
echo ""
echo "Waiting for process to stop..."
wait $pid

# start normally
echo "Starting mysql-server normally"
service mysql start
service mysql status

echo ""
echo "Done."