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sfill

Securely wipe free disk space

TLDR

Securely wipe free space (38 passes)
$ sfill /path/to/mounted_disk
copy
Reduced security wipe with 2 passes
$ sfill -l -v /path/to/mounted_disk
copy
Fastest wipe with 1 random pass
$ sfill -ll -v /path/to/mounted_disk
copy
Wipe only free space (not inodes)
$ sfill -I /path/to/mounted_disk
copy
Wipe only free inodes
$ sfill -i /path/to/mounted_disk
copy

SYNOPSIS

sfill [options] directory

DESCRIPTION

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.

PARAMETERS

-l

Lessens security. Only two passes are written: one with 0xff and a final one with random values.
-ll
Lessens security even further. Only one random pass is written.
-v
Verbose mode; show progress
-I
Overwrite only free disk space, not inodes
-i
Overwrite only free inodes, not disk space
-f
Fast and insecure mode. No /dev/urandom, no synchronize mode.
-z
Final overwrite with zeros instead of random data

CAVEATS

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.

HISTORY

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

SEE ALSO

srm(1), shred(1), wipe(1)

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