SHRED

Section: User Commands (1)
Updated: March 2021
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NAME

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 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/>

COPYRIGHT

Copyright © 2020 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.