How confident are you that when you ‘delete’ a file, it really get deleted/removed/erased/wiped from your hard disk?
The fact is, the ‘delete’ command does not remove your file(s). It simply tells your system to free up the space for other data. Until the space been filled with new data, your file(s) will still remain on the disk itself. That is to say, with some simple recovery tools, the files can be easily recovered. Now, if you want to completely eradicate porns files that contain sensitive information, you have to do more than just ‘delete’ and ‘empty trash’
Shred is a shell command that allows you to securely erase any files. It overwrites the specified file(s) repeatedly, in order to make it harder for even very expensive hardware probing to recover the data.
Shred is included in many Linux distributions, thus you can use it immediately, without any further installation.
To shred a file,
shred -f -v -z -u file.txt
-f: change permissions to allow writing if necessary
-v: verbose, to display the progress
-z: add a final overwrite with zeros to hide shredding
-u: truncate and remove file after overwriting
You can type shred –help (with two ‘-’ in front of the help) to display a list of options.
Adding shred to Nautilus menu
You can also add shred to your nautilus menu for convenience sake.
1. Install nautilus-actions from your Synaptic Package Manager, or in the terminal, type
sudo apt-get install nautilus-actions
2. Open up Nautilus Actions Configuration (System->Preference->Nautilus Actions Configuration)
3. Click Add
4. Fill in the following details:
Tooltip: Use the shred utility to securely erase files
Parameters: -f -u -v -z %M
5. Click on the Conditions tab
6. Under the “Appears if selection contains“, check “both”
7. Check the box “Appears if selection has multiple files or folders“. Click OK
8. Open up a terminal, type
Now right click on any files, you should be able to see the shred command in the menu.
PS: While this is a useful tool to erase files, it is not guaranteed to be effective in the following conditions:
- log-structured or journaled file systems, such as XFS and Ext3
- file systems that write redundant data and carry on even if some writes
- fail, such as RAID-based file systems
- file systems that make snapshots, such as Network Appliance’s NFS server
- file systems that cache in temporary locations, such as NFS version 3 clients
- compressed file systems