how to change root password of mysql in ubuntu code example

Example 1: change root password mysql

#First Login with administrative account (Even root itself)

mysql> use mysql;
mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD("NewPassword");
mysql> flush privileges;

#Now quit and login
mysql> quit

mysql -u root -p
#Click enter and It will prompt you to enter password
#Just to be safe you should also still try to log in without entering a password

Example 2: change mysql root password

$ sudo cat /etc/mysql/debian.cnf
Note the lines which read:

user     = debian-sys-maint
password = blahblahblah
Then:

$ mysql -u debian-sys-maint -p
Enter password: // type 'blahblahblah', ie. password from debian.cnf

mysql> USE mysql
mysql> SELECT User, Host, plugin FROM mysql.user;
+------------------+-----------+-----------------------+
| User             | Host      | plugin                |
+------------------+-----------+-----------------------+
| root             | localhost | auth_socket           |
| mysql.session    | localhost | mysql_native_password |
| mysql.sys        | localhost | mysql_native_password |
| debian-sys-maint | localhost | mysql_native_password |
+------------------+-----------+-----------------------+
4 rows in set (0.00 sec)

mysql> UPDATE user SET plugin='mysql_native_password' WHERE User='root';
mysql> COMMIT;  // When you don't have auto-commit switched on
Either:

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'new_password';
Or:

// For MySQL 5.7+
UPDATE mysql.user SET authentication_string=PASSWORD('new_password') where user='root';
Then:

mysql> FLUSH PRIVILEGES;
mysql> COMMIT;  // When you don't have auto-commit switched on
mysql> EXIT

$ sudo service mysql restart
$ mysql -u root -p
Enter password: // Yay! 'new_password' now works!