To create a database:
CREATE DATABASE name;

To create a user:
GRANT ALL PRIVILEGES ON dbname.* TO 'monty'@'localhost' IDENTIFIED BY 'password';

To reload grant tables:
mysqladmin reload -p

To set a password:
SET PASSWORD = PASSWORD('biscuit'); (for the user you're logged in as)
SET PASSWORD FOR 'jeffrey'@'%' = PASSWORD('biscuit');

Export all databases:
mysqldump -u user -p database [table 1]

Import all databases:
mysqlimport -u user -p database < import.sql

Search and replace text in fields:

UPDATE [table] SET [field] = replace( [field], "search_for", "replace_with" ); 

Updated Jan 30, 2008