shred - Man Page

overwrite a file to hide its contents, and optionally delete it

Examples (TL;DR)

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 disk. 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'

Referenced By

dd_rescue(1), logrotate(8), nwipe(1), ptrash(1), rm(1), scrub(1), srm(1).

April 2021 GNU coreutils 8.32