Changing MySQL root password

Sometimes you forget the root password, or something went wrong 
modifying it. Here's how to reset the root password for mysql on a 
Redhat Linux box:

[root@host root]#killall mysqld
[root@host root]#/usr/libexec/mysqld -Sg --user=root &
[root@host root]# mysql
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 1 to server version: 3.xx.xx

Type 'help;' or 'h' for help. Type 'c' to clear the buffer.

mysql> USE mysql

Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

mysql> UPDATE user
-> SET password=password("newpassword")
-> WHERE user="root";

Query OK, 2 rows affected (0.03 sec)
Rows matched: 2 Changed: 2 Warnings: 0

mysql> flush privileges;

Query OK, 0 rows affected (0.02 sec)

mysql> exit;
[root@host root]#killall mysqld

Then start MySQL again:

/etc/init.d/mysqld start