Start MySQL server from the command line on Mac OS Lion

I installed mySQL for my Mac. Beside starting the SQL server with mySQL.prefPane tool installed in System Preference, I want to know the instruction to start from command-line.
I do as follow:

After

su root

I start the mySQL server by command-line, it produce error as below:

sh-3.2# /usr/local/mysql/bin/mysqld

111028 16:57:43 [Warning] Setting lower_case_table_names=2 because
file system for /usr/local/mysql-5.5.17-osx10.6-x86_64/data/ is case
insensitive

111028 16:57:43 [ERROR] Fatal error: Please read “Security” section of
the manual to find out how to run mysqld as root!

111028 16:57:43 [ERROR] Aborting

111028 16:57:43 [Note] /usr/local/mysql/bin/mysqld: Shutdown complete

Please help me!