How do I retrieve my MySQL username and password?

I lost my MySQL username and password. How do I retrieve it?

 Answers

Stop the MySQL process.

Start the MySQL process with the --skip-grant-tables option.

Start the MySQL console client with the -u root option.

List all the users;

SELECT * FROM mysql.user;

Reset password;

UPDATE mysql.user SET Password=PASSWORD('[password]') WHERE User='[username]';

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But DO NOT FORGET to

Stop the MySQL process

Start the MySQL Process normally (i.e. without the --skip-grant-tables option)

when you are finished. Otherwise, your database's security could be compromised.

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An improvement to the most useful answer here:

1] No need to restart the mysql server 
2] Security concern for a MySQL server connected to a network

There is no need to restart the MySQL server.

use FLUSH PRIVILEGES; after the update mysql.user statement for password change.

The FLUSH statement tells the server to reload the grant tables into memory 

so that it notices the password change.

The --skip-grant-options enables anyone to connect without a password and

 with all privileges. Because this is insecure, you might want to

use --skip-grant-tables in conjunction with --skip-networking to prevent remote 

clients from connecting.

from: reference: resetting-permissions-generic

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If you have root access to the server where mysql is running you should stop

 the mysql server using this command

sudo service mysql stop

Now start mysql using this command

sudo /usr/sbin/mysqld --skip-grant-tables  --skip-networking &

Now you can login to mysql using

sudo mysql
FLUSH PRIVILEGES;
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('MyNewPass');

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Although a strict, logical, computer science'ish interpretation of the op's question 

would be to require both "How do I retrieve 

my MySQL username" and "password" - I thought It might be useful to someone 

to also address the OR interpretation. In other words ...

1) How do I retrieve my MySQL username?

OR

2) password

This latter condition seems to have been amply addressed already so I won't bother with it. 

The following is a solution for the case "How do i retreive my MySQL username" alone. HIH.

To find your mysql username run the following commands from the mysql shell ...

SELECT User FROM mysql.user;

it will print a table of all mysql users.

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Do it without down time

Run following command in the Terminal to connect to the DBMS (you need root access):

sudo mysql -u root -p;

run update password of the target user (for my example username is mousavi and it's 

password must be 123456):

UPDATE mysql.user SET authentication_string=PASSWORD('123456')

 WHERE user='mousavi';

at this point you need to do a flush to apply changes:

FLUSH PRIVILEGES;

Done! You did it without any stop or restart mysql service.