An fatal distribute system like GFS(Google File System)
专门学习分布式文件系统用，没法上生产的。
现在bug很多，单机版本，所有的东西都没有写入文件持久化，只在内存持久化了。
参照Google File System实现的。 你只能试试看这样玩。
直接运行BFSClient就可以跑起来啦。
ls to list the file eg: ls /bfs
get to get the file eg: get /bfs/some.log
put to put a file eg: put 'some' /bfs/some.log
delete to delete a file delete /bfs/some.log
if you want to exit the command , input :exit
put "kkk" /some/big.log
ls /some
put "abc" /some/a.log
ls /some
get /some/big.log
get /some/a.log