mysqld will not start-problem with /tmp/mysql.sock

My solution to the [ERROR] Can't start server : Bind on unix socket: Permission denied
problem was to change ownership of the directories:
/usr/local/var/run/mysqld
/usr/local/var/db/mysql

sudo chown -R _mysql /usr/local/var/run/mysqld

via:http://bugs.mysql.com/bug.php?id=11380