SHRED's testing my head

[kevv]

As a first time user of SHRED I wanted to be sure that things would work EXACTLY as expected.
Just as well too!
So, I made a small partition of 8MB, zeroed it out, formated it to EXT2, & then stored a load of text files in it.
Then:- I used dd to copy an image of the partition to a file (a), SHREDed one of the text files in the partition [using the zero-out-after and the leave-the-name-in-the-directory options] and then made another image-copy of the partion (b).
Clicking on the filename in the file manager the file opened as a 'nil' document [so far so good].
Using KHexedit I then looked in both (a) and for (b) for the file; it was in both!
So I did 'sync' in a shell root terminal, made another image-copy of the partition and looked again, - still there! =(:-o
So then from the file manager, I opened the the 'SHREDed' file modified it, saved it, made another image-copy of the partition and looked again for the original file, - still there! =(:-O
(I am still on kernel 2.6.19 so maybe the above is no longer an issue)

Uhmm, - can anybody tell me please - what's going on here? - 'coz I haven't a clue!

[gerard4143]

I found this in info shred

However, the command `shred - >file' does not shred the contents of
FILE, since the shell truncates FILE before invoking `shred'. Use the
command `shred file' or (if using a Bourne-compatible shell) the
command `shred - 1<>file' instead.

Does it apply here.

[nmset]

Unless I misunderstood your post, you seem to say that the shredded file should have been absent in your partition images. Shred just overwrites files and do not delete them unless the -r option is specified. Can you post your actual command usage ?

[kevv]

Thanks for your replys.
gerard4143: I'm not sure [i am not fluent enough in shell script]. At the moment i dont think so. Going to post that.
nmset: there is no -r option; there is a -u option, but i did not use it. I did:
shred -n 1 -z file
this leaves the directory entry intact and rounds up the [now zeroed file] size to a whole number of blocks (eg 4096 bytes on mine). What is happening on mine is that as well as the directory entry, the data bytes are not [apparently] being touched. I t seems to me that a [non sync-able] cache is being held somewhere of the partiiton and that it is that whichis being shreded.