FreeBSD系统忘记了root密码的恢复办法.

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to enter Single User mode. At the 
question about the shell to use, hit ENTER. You will be dropped to a # 
prompt. Enter mount -u / to remount your root filesystem read/write, then 
run mount -a to remount all the filesystems. Run passwd root to change the 
root password then run exit to continue booting.