Quoting the MySQL docs(http://dev.mysql.com/doc/refman/5.1/en/password-security-user.html):
Store your password in an option file. For example, on Unix you can list your password in the [client] section of the .my.cnf file in your home directory:
[client] password=your_pass
To keep the password safe, the file should not be accessible to anyone but yourself. To ensure this, set the file access mode to 400 or 600. For example:
shell> chmod 600 .my.cnf
To name from the command line a specific option file containing the password, use the
--defaults-file=file_name
option, wherefile_name
is the full path name to the file.