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SHRED

Section: User Commands (1)
Updated: February 2026
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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.

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-f'-f, --forceX'tty: link': change permissions to allow writing if necessary
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-n'-n, --iterations=,NX'tty: link'/: overwrite N times instead of the default (3)
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-rando-source'--random-source=FILEX'tty: link': get random bytes from FILE
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-s'-s, --size=,NX'tty: link'/: shred this many bytes (suffixes like K, M, G accepted)
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-u'-uX'tty: link': deallocate and remove file after overwriting
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-remove'--remove[=HOW]X'tty: link': like -u but give control on HOW to delete; See below
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-v'-v, --verboseX'tty: link': show details of data and metadata operations performed
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-x'-x, --exactX'tty: link': do not round file sizes up to the next full block; this is the default for non-regular files
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#shre-z'-z, --zeroX'tty: link': add a final overwrite with zeros to hide shredding
X'tty: link https://www.gnu.org/software/coreutils/shred#shre-help'--helpX'tty: link': display this help and exit
X'tty: link https://www.gnu.org/software/coreutils/shred#shre-version'--versionX'tty: link': 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

Report bugs to: bug-coreutils@gnu.org

Report Gentoo bugs to: https://bugs.gentoo.org/
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
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