NAME
    shred -  delete a file securely, first overwriting it to hide its con-
    tents

SYNOPSIS
    shred [OPTIONS] FILE [...]

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

    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 (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
    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.  When operat-
    ing 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, Ext3, 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

    In addition, file system backups and remote mirrors may contain copies
    of the file that cannot be removed, and that will allow a shredded file
    to be recovered later.

AUTHOR
    Written by Colin Plumb.

REPORTING BUGS
    Report bugs to <bug-coreutils@gnu.org>.

COPYRIGHT
    Copyright (C) 2002 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
    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.