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Full Version: Securely ERASE a hard disc in linux
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as root do this


dd if=/dev/random of=/dev/hda && dd if=/dev/zero of=/dev/hda


ps. this takes a long time, so be patient (do it overnight or something)


thanks to Grep420








Not to rain on a great example but the DoD does suggest three write passes to full erase data. I seriously doubt normal recovery software could be done successfully after the 2 passes but companies like Vogon International do make claims of that sort of crazy recovery.


Also for some more dry reading a techinal proposal on ATA secure erase.

I though it was hard trying to recover files on the normal ext3 file system [img]<___base_url___>/uploads/emoticons/default_dry.png[/img] never did

recover them.


Anyways also run the shred command :)this overwrites the file


shred -v -n 1024 file.txt



shred -v -n 1024 file


heh i know i said more than 2 but 1024 maybe a little bit of paranoia kickin in! exactly what dont you want us to find [img]<___base_url___>/uploads/emoticons/default_laugh.png[/img]


shred -n 25 -u -v -z file


i think that should be enough.


-n 25 = 25 times over (the default)

-u = remove file first before writing

-v = be verbose (always do this to stop yourself from getting itchy)

-z = final overwrite with zeroes (to clear evidence of shred)



And start from the man:


Quote:The following are examples of filesystems on which shred is not effective:* log-structured or journaled filesystems, such as those supplied with

    AIX and Solaris (and JFS, ReiserFS, XFS, Ext3, etc.)

* filesystems that write redundant data and carry on even if some writes

    fail, such as RAID-based filesystems

* filesystems that make snapshots, such as Network Appliance's NFS server

* filesystems that cache in temporary locations, such as NFS

    version 3 clients

* compressed filesystems