过去在 GNU/Linux 里，冻仁会使用 dd，此指令会将资料填零而达到抹除磁盘的功用，但就算这样还是有被专业人士还原的风险；现在冻仁都改用 shred指令来完成这项任务，此指令是专门用来撕碎资料的。
将 /dev/sdX 装置填零。
dd if=/dev/zero of=/dev/sdX bs=1M
开始 shred 之前，您必须先安装 coreutils 套件。
$ sudo aptitude install coreutils# -v 顯示進度。# -f 強制寫入，必要時允許變更權限寫入。# -z 用零覆寫並撕碎。# -n 指定覆寫次數。# -n 指定覆寫次數。
抹除硬盘
$ sudo shred -vfz -n 10 /dev/sdXshred: /dev/sdX：11 次之第 1 次 (random)...shred: /dev/sdX：11 次之第 1 次 (random)...471MiB/932GiB 0%shred: /dev/sdX：11 次之第 1 次 (random)...472MiB/932GiB 0%shred: /dev/sdX：11 次之第 1 次 (random)...949MiB/932GiB 0%......
抹除档案
$ shred -vu -n 10 hello-sherd.txtshred: hello-sherd.txt: pass 1/3 (random)...shred: hello-sherd.txt: pass 2/3 (random)...shred: hello-sherd.txt: pass 3/3 (random)...shred: hello-sherd.txt: removingshred: hello-sherd.txt: renamed to 000000000000000shred: 000000000000000: renamed to 00000000000000shred: 00000000000000: renamed to 0000000000000shred: 0000000000000: renamed to 000000000000shred: 000000000000: renamed to 00000000000shred: 00000000000: renamed to 0000000000shred: 0000000000: renamed to 000000000shred: 000000000: renamed to 00000000shred: 00000000: renamed to 0000000shred: 0000000: renamed to 000000shred: 000000: renamed to 00000shred: 00000: renamed to 0000shred: 0000: renamed to 000shred: 000: renamed to 00shred: 00: renamed to 0shred: hello-sherd.txt: removed
※ shred 在 ext3, ext4 这类的日志档案系统上运作时可能无法完整清除，若真不放心可以试试 hdparm。