How to use the command 'sdelete' (with examples)

Secure deletion is an essential part of data management and protection, particularly when it involves sensitive information. The command-line tool ‘sdelete’ offers a robust solution by permanently erasing files, directories, or entire volumes, thus ensuring that data cannot be recovered. Developed by Sysinternals, ‘sdelete’ employs advanced algorithms to overwrite data, mitigating the risk of unauthorized data access. Below we explore various use cases, each tailored to different secure deletion needs.

Use case 1: Delete files with 3 passes

Code:

sdelete -p 3 path\to\file1 path\to\file2 ...

Motivation:

When dealing with sensitive or personal information stored in files, simply deleting them isn’t enough. Standard deletion only removes the file’s directory entry, leaving its content recoverable until overwritten. The ‘sdelete’ command ensures these files are irretrievably deleted by overwriting them multiple times. In this case, using 3 passes makes it exceedingly difficult for any recovery tools to retrieve the original content.

Explanation:

• sdelete: The command used for securely deleting files.
• -p 3: The flag -p specifies the number of passes ‘sdelete’ will use to overwrite the files. Here, it overwrites them three times.
• path\to\file1 path\to\file2 ...: These are the paths to the files you wish to delete securely. Replace with actual file paths on your system.

Example Output:

Securely deleting path\to\file1 ...
Securely deleting path\to\file2 ...
Files successfully deleted with 3 overwrite passes.

Use case 2: Delete folders and its subdirectories with 1 pass

Code:

sdelete -s path\to\directory1 path\to\directory2 ...

Motivation:

Whole directories often contain multiple files and subdirectories that need secure deletion. Whether you are clearing out old project files or ensuring customer data is disposed of correctly, the ability to wipe entire directories, including subdirectories, is crucial. The default single pass deletion is suitable for less sensitive data or when time is a critical factor.

Explanation:

• sdelete: The tool used for secure deletion.
• -s: This flag tells ‘sdelete’ to process each directory path recursively, encompassing all files and subdirectories within.
• path\to\directory1 path\to\directory2 ...: These are the paths to the directories you need to delete. You should provide paths relevant to your system.

Example Output:

Recursively deleting directory: path\to\directory1
Recursively deleting directory: path\to\directory2
Directories and subdirectories deleted successfully with 1 overwrite pass.

Use case 3: Clean the free space of volume D: with 3 passes

Code:

sdelete -p 3 D:

Motivation:

Simply deleting files does not wipe the disk space they previously occupied. This could leave data remnants that might be recovered through advanced data recovery techniques. Cleaning the free space on a volume ensures that previously deleted files cannot be recovered. This is particularly vital for safeguarding against the accidental recovery of residual data on a shared or retiring system.

Explanation:

• sdelete: The command being executed.
• -p 3: Indicates that the free space will be overwritten three times to maximize data sanitization.
• D:: This specifies the drive letter of the volume whose free space is to be cleaned. Adjust it according to the volume on your machine.

Example Output:

Cleaning free space on volume D:
Free space cleaned with 3 overwrite passes.

Use case 4: Clean the free space with zeros of physical disk 2

Code:

sdelete -z 2

Motivation:

In certain cases, cleaning the free space on a whole physical disk is necessary, especially if it has been repartitioned or is being decommissioned and should not contain any sensitive remnants of data. Writing zeros to the free space represents a basic, yet effective method of ensuring that no data can be reconstructed.

Explanation:

• sdelete: The command for disk sanitation.
• -z: This flag instructs ‘sdelete’ to write zeros over the available free space, a less intensive option than multiple passes and suitable for non-critical data.
• 2: This specifies the target physical disk, identified by its index number. Ensure this corresponds to the correct disk on your system.

Example Output:

Cleaning free space on physical disk 2 with zeros.
Free space on physical disk 2 has been zeroed out successfully.

Conclusion

The ‘sdelete’ command is an indispensable tool for individuals and organizations aiming to achieve data confidentiality. Whether you are securely deleting single files, entire directories, or cleaning unused disk space, ‘sdelete’ provides a comprehensive suite of options to prevent data leakage and ensure privacy. By understanding and correctly applying the command in various scenarios, users can significantly enhance their data management practices and security posture.