sfill

Securely wipe free space (38 writes)

$ sfill /path/to/mounted_disk

$ sfill -l -v /path/to/mounted_disk

$ sfill -ll -v /path/to/mounted_disk

$ sfill -I /path/to/mounted_disk

$ sfill -i /path/to/mounted_disk

sfill [options] directory

sfill securely overwrites the free space and inodes of a partition where the specified directory resides. It uses multiple passes to prevent recovery of previously deleted files.

-l

Use less secure mode with fewer overwrites (6 passes instead of 38)

Use fast mode with single overwrite pass

Verbose mode; show progress

Overwrite only free disk space, not inodes

Overwrite only free inodes, not disk space

Force operation without prompting

Final overwrite with zeros instead of random data

This operation is time-consuming, especially with the default 38 passes. SSDs may not be effectively wiped due to wear leveling. The target must be a mounted filesystem, not a raw device.

sfill is part of the secure-delete package, providing tools for securely erasing data to prevent forensic recovery.

srm(1), smem(1), sswap(1), shred(1)