NAME    [Toc]    [Back]

       shred  -  delete a file securely, first overwriting it to hide its contents

SYNOPSIS    [Toc]    [Back]

       shred [OPTIONS] FILE [...]

DESCRIPTION    [Toc]    [Back]

       Overwrite the specified FILE(s) repeatedly, in order to make it	harder
       for even very expensive hardware probing to recover the data.

       -f, --force
	      change permissions to allow writing if necessary

       -n, --iterations=N
	      Overwrite N times instead of the default (25)

       -s, --size=N
	      shred this many bytes (suffixes like k, M, G accepted)

       -u, --remove
	      truncate and remove file after overwriting

       -v, --verbose
	      show progress

       -x, --exact
	      do not round file sizes up to the next full block

       -z, --zero
	      add a final overwrite with zeros to hide shredding

       -      shred standard output

       --help display this help and exit

       --version
	      print 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.  When operating
 on regular files, most people use the --remove option.

       CAUTION: Note that shred relies on a very  important  assumption:  that
       the  filesystem	overwrites data in place.  This is the traditional way
       to do things, but many modern filesystem designs do  not  satisfy  this
       assumption.   The  following are examples of filesystems on which shred
       is not effective:

       * log-structured or journaled filesystems, such as those supplied with

	      AIX and Solaris (and JFS, ReiserFS, XFS, etc.)

       * filesystems that write redundant data	and  carry  on	even  if  some
       writes

	      fail, such as RAID-based filesystems

       *  filesystems  that  make  snapshots,  such as Network Appliance's NFS
       server

       * filesystems that cache in temporary locations, such as NFS

	      version 3 clients

       * compressed filesystems

AUTHOR    [Toc]    [Back]

       Written by Colin Plumb.

REPORTING BUGS    [Toc]    [Back]

       Report bugs to <bug-fileutils@gnu.org>.

COPYRIGHT    [Toc]    [Back]

       Copyright (C) 2001 Free Software Foundation, Inc.
       This is free software; see the source for copying conditions.  There is
       NO  warranty;  not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
       PURPOSE.

SEE ALSO    [Toc]    [Back]

       The full documentation for shred is maintained as a Texinfo manual.  If
       the  info  and  shred programs are properly installed at your site, the
       command

	      info shred

       should give you access to the complete manual.



shred (fileutils) 4.1		  March 2002			      SHRED(1)