ubuntu: destroy a huge binary file and make it non-readable.

[John R. Sowden]

On 01/26/2014 01:51 AM, Johnny Rosenberg wrote:
> 2014-01-25 ping song <songpingemail at gmail.com 
> <mailto:songpingemail at gmail.com>>
>
>     thanks.
>     but guess I haven't make it clear.
>
>     my goal is to :
>     1) not to delete the file, not to chmod either
>     2) don't change the file size either
>     3) make the gzip file not being able to ungzipped and viewed -
>     just to mess up the file and make it not usable (what I meant
>     "destroy").
>
>     I finally use GNU "head" to delete the last a couple of lines like
>     this:
>
>     head --lines=-100 myfile.gz > newfile.gz
>
>     after this , gzip can't recogize it. that's it.
>
>     but , I doubt this is not the safe way, coz an gzip expert might
>     be easily open the binary file and fixed the missed lines (I'm not
>     sure).
>
>     maybe I better 'sort' the whole file, or, swap randomly some
>     lines, so there is no way the file can be read...
>
>
>
> I know this is way off topic, but I'm just curious: Why do you want to 
> do this? Is the file ever going to be readable again? If not, why not 
> just delete it...? If you want to be able to open the file yourself 
> but nobody else, why not just protect it (encrypt it) with a password?
>
> Johnny Rosenberg
>
>
>
>
>     On Sat, Jan 25, 2014 at 12:09 PM, Liam Proven <lproven at gmail.com
>     <mailto:lproven at gmail.com>> wrote:
>
>         On 25 January 2014 16:17, ping song <songpingemail at gmail.com
>         <mailto:songpingemail at gmail.com>> wrote:
>         > may sounds like a sin, but I just wanna know the best way to
>         change a binary
>         > file without actually open it (since it's really huge)?
>
>         Your subject says "destroy". To me that would seem to mean
>         securely erase.
>
>         But your body text seems to ask about editing it.
>
>         As such, I do not understand what you mean.
>
>         If you do mean secure erase, read this:
>
>         http://askubuntu.com/questions/57572/how-to-delete-files-in-secure-manner
>
>
>         --
>         Liam Proven . Profile: http://lproven.livejournal.com/profile
>         Email: lproven at cix.co.uk <mailto:lproven at cix.co.uk> .
>         GMail/G+/Twitter/Flickr/Facebook: lproven
>         MSN: lproven at hotmail.com <mailto:lproven at hotmail.com> .
>         Skype/AIM/Yahoo/LinkedIn: liamproven
>         Tel: +44 20-8685-0498 <tel:%2B44%2020-8685-0498> . Cell: +44
>         7939-087884 <tel:%2B44%207939-087884>
>
>
we're all sitting on the edge of our chairs waiting for this answer :)

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