How to wipe free disk space in Linux?
This question is inspired by What is the best tool for file-shredding on a memory card?, in which brice recommended the simple pattern for wiping an SD card using
dd if=/dev/random. That's the solution to the problem I googled. brice++
I saw that question refer to the more general one: Is there a program to truly delete all deleted files?. But that question is tagged
windows. I'd like to add the Linux answer to our knowledge base. I use
shred -uz FWIW.
I'd also like to hear from experts about success against forensic techniques. (No, I am not under threat of indictment. I have nothing to hide from authorities. I'm just curious. ;) Does
shred(1) have a track record for thwarting subpoenas? What about brice's technique for the SD card? There are no forensic techniques to recover from flash once it's been overwritten in just a single pass, right?