tr '\000' '\377' < /dev/zero | dd of=/dev/$i bs=1024 count=1024000
tr '\000' '\377' < /dev/zero | dd of=/dev/$i bs=1024 count=1024000
倒着行走的蜗牛
tr '\000' '\377' < /dev/zero | dd of=/dev/$i bs=1024 count=1024000
