From Newsgroup: alt.os.linux.ubuntu

Just what subject says, I need a utility to scramble/ overwrite deleted
file space to make the files unrecoverable. I just read about Shred,
but it requires moving all existing files off of the drive first, then
doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On Wed, 11 Mar 2026 22:38:31 -0400, JR Dolobson wrote:

Just what subject says, I need a utility to scramble/ overwrite deleted
file space to make the files unrecoverable. I just read about Shred,
but it requires moving all existing files off of the drive first, then
doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you

If you have a ssd just issue the trim command.
--
Pull my finger
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On Wed, 3/11/2026 10:38 PM, JR Dolobson wrote:

Just what subject says, I need a utility to scramble/ overwrite deleted file space to make the files unrecoverable.  I just read about Shred, but it requires moving all existing files off of the drive first, then doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you

1) Unmount partition /dev/sdb2 # Can't have target partition mounted while this runs

2) sudo zerofree /dev/sdb2 # Writes the unallocated space, removing deleted material evidence

For the slash partition, boot with a LiveDVD (slash is now unmounted)
and try it out. The default fill is zeros, which is a good choice.

https://manpages.ubuntu.com/manpages/focal/man8/zerofree.8.html

sudo zerofree /dev/sdb2 # Zero out unmounted EXT family partition and its unallocated blocks
# Any undeleted files will not be touched
# Typical usage:
# Used just before doing a compact on a VHD container with EXtn inside
# Also used to zero unused parts of /dev/sdb2 before the usage of a dd.gz backup op.
# Zero the EXTn on /dev/sdb one at a time, then sudo dd and pipe to a compressor.

While backing up with "dd" is a pretty time-wasting thing to do,
it's part of preparing for the test of other backup programs. You
make "dd" backups because you know they work. Does NOT support resize particularly. dd tends to be for "like-to-like" situations (requires
lowest skill level of the user).

Anything requiring physical layer access to storage, needs elevation.
The compressor doesn't need to be elevated, as it comes later.

Zerofree does not support a very wide selection of partition types,
but I can still fit this into a workflow.

Example: 1TB drive with 20GB worth of OS files. Zerofree.
dd | then pipe to compressor, output file would be 20GB or less in size.
A good approach for partially filled partitions. All of the zeros,
can compress quite well.

Paul
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On 12/03/2026 02:38, JR Dolobson wrote:

Just what subject says, I need a utility to scramble/ overwrite deleted
file space to make the files unrecoverable. I just read about Shred,
but it requires moving all existing files off of the drive first, then
doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you

<https://docs.bleachbit.org/doc/shred-files-and-wipe-disks.html>

It's quite a lot to read, but worth spending the time on.
--
Jeff
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On Thu, 12 Mar 2026 02:34:36 -0400, Paul wrote:

While backing up with "dd" is a pretty time-wasting thing to do,
it's part of preparing for the test of other backup programs. You
make "dd" backups because you know they work.

Use rsync for backups. It has a --checksum option that lets you verify
the backup afterwards. What has dd got?

They don’t call it the “data destroyer” for nothing ...
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On 3/12/26 03:38, JR Dolobson wrote:

Just what subject says, I need a utility to scramble/ overwrite deleted
file space to make the files unrecoverable.  I just read about Shred,
but it requires moving all existing files off of the drive first, then
doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you

I usually create a file as root using all available free disk space:
dd if=/dev/zero of=/zerofile bs=128k; rm -f /zerofile
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On 3/12/26 03:38, JR Dolobson wrote:

Just what subject says, I need a utility to scramble/ overwrite deleted
file space to make the files unrecoverable.  I just read about Shred,
but it requires moving all existing files off of the drive first, then
doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you

It depends upon the contents of that deleted files: if they contain the
codes for some ICBMs or the passwords and access codes to some
multi-billion fortune, ask somebody else.

For us mere mortals:

Create a file as root using all available free disk space:
dd if=/dev/zero of=/zerofile bs=128k; rm -f /zerofile

Josef
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.ubuntu

On 3/12/26 2:34 AM, Paul wrote:

On Wed, 3/11/2026 10:38 PM, JR Dolobson wrote:

Just what subject says, I need a utility to scramble/ overwrite deleted file space to make the files unrecoverable.  I just read about Shred, but it requires moving all existing files off of the drive first, then doing a drive overwrite and/or overwriting the file no longer wanted.

Thank you

1) Unmount partition /dev/sdb2 # Can't have target partition mounted while this runs

2) sudo zerofree /dev/sdb2 # Writes the unallocated space, removing deleted material evidence

For the slash partition, boot with a LiveDVD (slash is now unmounted)
and try it out. The default fill is zeros, which is a good choice.

https://manpages.ubuntu.com/manpages/focal/man8/zerofree.8.html

sudo zerofree /dev/sdb2 # Zero out unmounted EXT family partition and its unallocated blocks
# Any undeleted files will not be touched
# Typical usage:
# Used just before doing a compact on a VHD container with EXtn inside
# Also used to zero unused parts of /dev/sdb2 before the usage of a dd.gz backup op.
# Zero the EXTn on /dev/sdb one at a time, then sudo dd and pipe to a compressor.

While backing up with "dd" is a pretty time-wasting thing to do,
it's part of preparing for the test of other backup programs. You
make "dd" backups because you know they work. Does NOT support resize particularly. dd tends to be for "like-to-like" situations (requires
lowest skill level of the user).

Anything requiring physical layer access to storage, needs elevation.
The compressor doesn't need to be elevated, as it comes later.

Zerofree does not support a very wide selection of partition types,
but I can still fit this into a workflow.

Example: 1TB drive with 20GB worth of OS files. Zerofree.
dd | then pipe to compressor, output file would be 20GB or less in size.
A good approach for partially filled partitions. All of the zeros,
can compress quite well.

Paul

Unfortunately, I neglected to mention that both attached USB drives are
NTFS, so it doesn't appear that the Zerofree will work with them. So,
same as above request except for NTFS. Sorry!
--- Synchronet 3.21d-Linux NewsLink 1.2