shred doesn’t even necessarily work at the OS level. If you use something like ext3 and I assume ext4, normally when you overwrite data in a file, you’re not overwriting data even at the logical level in the block device. Journalling entails that you commit data to somewhere else on the disk, then update the metadata atomically to reference the new data.
It was more-practical in an era of older filesystems.
shreddoesn’t even necessarily work at the OS level. If you use something likeext3and I assumeext4, normally when you overwrite data in a file, you’re not overwriting data even at the logical level in the block device. Journalling entails that you commit data to somewhere else on the disk, then update the metadata atomically to reference the new data.It was more-practical in an era of older filesystems.