shred - overwrite a file to hide its contents, and optionally delete it
shred [
OPTION]...
FILE...
Overwrite the specified FILE(s) repeatedly, in order to make it harder for even
very expensive hardware probing to recover the data.
If FILE is -, shred standard output.
Mandatory arguments to long options are mandatory for short options too.
-
-f, --force
- change permissions to allow writing if necessary
-
-n, --iterations=N
- overwrite N times instead of the default (3)
-
--random-source=FILE
- get random bytes from FILE
-
-s, --size=N
- shred this many bytes (suffixes like K, M, G accepted)
- -u
- deallocate and remove file after overwriting
-
--remove[=HOW]
- like -u but give control on HOW to delete; See
below
-
-v, --verbose
- show progress
-
-x, --exact
- do not round file sizes up to the next full block;
- this is the default for non-regular files
-
-z, --zero
- add a final overwrite with zeros to hide shredding
- --help
- display this help and exit
- --version
- output version information and exit
Delete FILE(s) if
--remove (
-u) is specified. The default is not
to remove the files because it is common to operate on device files like
/dev/hda, and those files usually should not be removed. The optional
HOW parameter indicates how to remove a directory entry: 'unlink' => use a
standard unlink call. 'wipe' => also first obfuscate bytes in the name.
'wipesync' => also sync each obfuscated byte to the device. The default
mode is 'wipesync', but note it can be expensive.
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.
Written by Colin Plumb.
GNU coreutils online help: <
https://www.gnu.org/software/coreutils/>
Report any translation bugs to <
https://translationproject.org/team/>
Copyright © 2022 Free Software Foundation, Inc. License GPLv3+: GNU GPL
version 3 or later <
https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO
WARRANTY, to the extent permitted by law.
Full documentation <
https://www.gnu.org/software/coreutils/shred>
or available locally via: info '(coreutils) shred invocation'