使用 shred /dev/hda 就可以让你的硬盘数据立刻消失，永不超升。当然要使用你的硬盘的正确的设备文件。
默认情况下使用各种垃圾数据反复重写25遍，加上 -v 参数就可以看到。
~~~snip~~~
$ shred -v /dev/hda
shred: /dev/hda: pass 1/25 (random)...
shred: /dev/hda: pass 2/25 (492492)...
shred: /dev/hda: pass 3/25 (000000)...
shred: /dev/hda: pass 4/25 (aaaaaa)...
shred: /dev/hda: pass 5/25 (555555)...
shred: /dev/hda: pass 6/25 (cccccc)...
shred: /dev/hda: pass 7/25 (b6db6d)...
shred: /dev/hda: pass 8/25 (333333)...
shred: /dev/hda: pass 9/25 (6db6db)...
shred: /dev/hda: pass 10/25 (dddddd)...
shred: /dev/hda: pass 11/25 (222222)...
shred: /dev/hda: pass 12/25 (ffffff)...
shred: /dev/hda: pass 13/25 (random)...
shred: /dev/hda: pass 14/25 (eeeeee)...
shred: /dev/hda: pass 15/25 (924924)...
shred: /dev/hda: pass 16/25 (777777)...
shred: /dev/hda: pass 17/25 (999999)...
shred: /dev/hda: pass 18/25 (111111)...
shred: /dev/hda: pass 19/25 (888888)...
shred: /dev/hda: pass 20/25 (bbbbbb)...
shred: /dev/hda: pass 21/25 (db6db6)...
shred: /dev/hda: pass 22/25 (444444)...
shred: /dev/hda: pass 23/25 (666666)...
shred: /dev/hda: pass 24/25 (249249)...
shred: /dev/hda: pass 25/25 (random)...
~~~snip~~~
参考 man shred。