网上很多方法都是：/usr/local/mysql/scripts/mysql_install_db --user=mysql
但是很有可能报错，找不到bin目录中的my_print_defaults
错误信息：
FATALERROR:Couldnotfind./bin/my_print_defaults
If you are using a binary release, you must run this script from
within the directory the archive extracted into. If you compiled
MySQL yourself you must run 'make install' first.
或
[root@bogon scripts]# /usr/local/mysql/scripts/mysql_install_db --user=mysql&
[1] 16874
[root@bogon scripts]#
FATAL ERROR: Could not find ./bin/my_print_defaults
If you compiled from source, you need to run 'make install' to copy the software into the correct location ready for operation.
If you are using a binary release, you must either be at the top level of the extracted archive, or pass the --basedir option pointing to that location.
解决方法：
[root@bogon scripts]# /usr/local/mysql/scripts/mysql_install_db --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data &
(这点非常重要)
FreeBSD下的解决办法是：
/usr/local/bin/mysql_install_db --user=mysql --basedir=/usr/local/ --datadir=/var/db/mysql &
