Mysql reset root password

# /etc/init.d/mysqld stop
# mysqld_safe --skip-grant-tables &
# mysql -u root

mysql> use mysql;
mysql> update user set password=PASSWORD("yournewpasswordhere") where User='root';
mysql> flush privileges;
mysql> quit

# /etc/init.d/mysqld stop
# /etc/init.d/mysqld start

Now you can login with your new password
# mysql -u root -p

mysql backup

Command which I am using for back up
mysqldump --single-transaction --all-databases -u username --password=password> backup_sunday_1_PM.sql