NAME

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

SYNOPSIS

       shred [-f|--force] [-n|--iterations] [-s|--size] [-u|--remove] [-v|--verbose] [-x|--exact]
       [-z|--zero] [-h|--help] [-V|--version] [file]

DESCRIPTION

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

OPTIONS

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

       -n, --iterations=NUMBER [default: 3]
              overwrite N times instead of the default (3)

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

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

       -h, --help
              Print help

       -V, --version
              Print version

       [file]

EXTRA

       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.

       CAUTION:  Note  that  shred  relies  on  a very important assumption: that the file system
       overwrites data in place.  This is the traditional way to do things, but many modern  file
       system designs do not satisfy this assumption.  The following are examples of file systems
       on which shred is not effective, or is not guaranteed to be effective in all  file  system
       modes:

        * log-structured or journal file systems, such as those supplied with
          AIX and Solaris (and JFS, ReiserFS, XFS, Ext3, etc.)

        * file systems that write redundant data and carry on even if some writes
          fail, such as RAID-based file systems

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

        * file systems that cache in temporary locations, such as NFS
          version 3 clients

        * compressed file systems

       In  the  case  of  ext3  file  systems, the above disclaimer applies (and shred is thus of
       limited effectiveness) only in data=journal mode, which journals file data in addition  to
       just  metadata.   In both the data=ordered (default) and data=writeback modes, shred works
       as usual. Ext3 journal modes can be changed by adding the  data=something  option  to  the
       mount  options  for  a particular file system in the /etc/fstab file, as documented in the
       mount man page (man mount).

       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.

VERSION

       v0.0.20

                                           shred 0.0.20                                  shred(1)