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-<devname>-<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
          suffixes 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
          signature.

   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/.

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Free and Open Source Software