shred - overwrite a file to hide its contents, and optionally delete it
SYNOPSIS
shred [OPTION]... FILE...
DESCRIPTION
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.
AUTHOR
Written by Colin Plumb.
REPORTING BUGS
GNU coreutils online help: [https://www.gnu.org/software/coreutils/] Report any translation bugs to [https://translationproject.org/team/]
SEE ALSO
Full documentation [https://www.gnu.org/software/coreutils/shred] or available locally via: info '(coreutils) shred invocation'
Packaged by Debian (9.7-3) Copyright © 2025 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.