of: Overwrite Files

1. Purpose

This script securely overwrites existing files in a directory, including all of its nested sub directories.

Before you sell your computer or give it to another person or give back your work computer to the company when you quit a job, you must securely delete your important personal files. Deleting or overwriting a file once is not secured enough. Anybody can use appropriate tools to recover the original file's content.

This script overwrites the files 20 times with random strings. Nobody can recover the original contents of the files.

2. Prerequisites

You must have Ruby interpreter installed on your computer.

Verify whether Ruby is installed:

• Open terminal.

• Type ruby -v, if you have Ruby installed on your machine, you should see something similar to this:

ruby 3.3.2 (2024-05-30 revision e5a195edf6) [x86_64-darwin22]

(The ruby version on your machine might be different.)

If you don't have Ruby installed on your machine, search "How to download and install Ruby" to find a way to install Ruby on your machine.

3. Run the program

• Download the file of.rb to your machine.

• Open terminal.

• Change the directory to where you save the file of.rb

• Run the command:

ruby of.rb <PATH TO THE DIRECTORY TO OVERWRITE FILES>

Example:

ruby of.rb $HOME/test_of

After running the script, you can check the file error_log.txt for any errors happening during the overwriting process.