[throwaway29303]

Reminder that shred(1) doesn't work on journaled filesystems.[0][1][2]

  CAUTION: shred assumes the file system and hardware overwrite data
  in place.  Although this is common, many platforms operate
  otherwise.  Also, backups and mirrors may contain unremovable
  copies that will let a shredded file be recovered later.  See the
  GNU coreutils manual for details.

[0] - https://man7.org/linux/man-pages/man1/shred.1.html

[1] - https://stackoverflow.com/questions/913282/shred-doesnt-work...

[2] - https://en.wikipedia.org/wiki/Journaling_file_system

[uws]

Thank you for your detailed assessment. I have updated the script to fill the directories with random data (to match original size) at the end to help prevent recovery further.