wipefs

WIPEFS(8)                    System Administration                   WIPEFS(8)

NAME
       wipefs - wipe a signature from a device

SYNOPSIS
       wipefs [-ahnpqtV] [-o offset] device...

DESCRIPTION
       wipefs  can erase filesystem, raid or partition-table signatures (magic
       strings) from the specified device to make the signatures invisible for
       libblkid.

       wipefs does not erase the filesystem itself nor any other data from the
       device.  When used  without  any  options,  wipefs  lists  all  visible
       filesystems and the offsets of their basic signatures.

       wipefs  calls  the BLKRRPART ioctl when it has erased a partition-table
       signature to inform the kernel about the change.

       Note that some filesystems and some partition tables store  more  magic
       strings  on the device.  The wipefs command lists only the first offset
       where a magic string has been detected.  The device is not scanned  for
       additional  magic strings for the same filesystem.  It is possible that
       after a wipefs -o offset the same filesystem or  partition  table  will
       still be visible because of another magic string on another offset.

       When option -a is used, all magic strings that are visible for libblkid
       are erased.

       Note that by default wipefs does not erase nested partition  tables  on
       non-whole disk devices.  For this the option --force is required.

OPTIONS
       -a, --all
              Erase  all  available  signatures.  The set of erased signatures
              can be restricted with the -t option.

       -b, --backup
              Create  a  signature  backup  to  the  file   $HOME/wipefs-<dev-
              name>-<offset>.bak.  For more details see the EXAMPLES section.

       -f, --force
              Force  erasure,  even  if  the  filesystem  is mounted.  This is
              required in order to erase  a  partition-table  signature  on  a
              block device.

       -h, --help
              Display help text and exit.

       -n, --no-act
              Causes everything to be done except for the write() call.

       -o, --offset offset
              Specify the location (in bytes) of the signature which should be
              erased from the device.  The offset number may  include  a  "0x"
              prefix;  then the number will be interpreted as a hex value.  It
              is possible to specify multiple -o options.

              The offset argument may be followed by the  multiplicative  suf-
              fixes  KiB  (=1024),  MiB  (=1024*1024), and so on for GiB, TiB,
              PiB, EiB, ZiB and YiB (the "iB" is optional, e.g.  "K"  has  the
              same   meaning  as  "KiB"),  or  the  suffixes  KB  (=1000),  MB
              (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.

       -p, --parsable
              Print out in parsable instead of printable format.   Encode  all
              potentially  unsafe  characters of a string to the corresponding
              hex value prefixed by '\x'.

       -q, --quiet
              Suppress any messages after a successful signature wipe.

       -t, --types list
              Limit the set of printed or erased signatures.   More  than  one
              type  may  be  specified in a comma-separated list.  The list or
              individual types can be prefixed with 'no' to specify the  types
              on  which  no  action  should  be  taken.   For more details see
              mount(8).

       -V, --version
              Display version information and exit.

EXAMPLES
       wipefs --all --backup /dev/sdb
              Erases all signatures from the device  /dev/sdb  and  creates  a
              signature  backup file ~/wipefs-sdb-<offset>.bak for each signa-
              ture.

       dd if=~/wipefs-sdb-0x00000438.bak of=/dev/sdb seek=$((0x00000438)) bs=1
       conv=notrunc
              Restores  an  ext2  signature  from  the  backup file  ~/wipefs-
              sdb-0x00000438.bak.

AUTHOR
       Karel Zak <kzak@redhat.com>

ENVIRONMENT
       LIBBLKID_DEBUG=all
              enables libblkid debug output.

SEE ALSO
       blkid(8), findfs(8)

AVAILABILITY
       The wipefs command is part of the util-linux package and  is  available
       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

util-linux                       December 2014                       WIPEFS(8)
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