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  options -a or -o, it lists all visible filesystems and the offsets of their basic
       signatures.

       wipefs calls BLKRRPART ioctl when erase partition table to inform kernel about the change.

       Note that some filesystems or some partition  tables  store  more  magic  strings  on  the
       devices.   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 wipefs -o offset the same filesystem or partition table will
       still be visible by another magic string on another offset.

       When used with option -a, 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. The option --force is required.


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

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

       -f, --force
              Force  erasure,  even  if  the filesystem is mounted.  This is required in order to
              erase the partition table 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 output messages after 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 ext2 signature from the backup file  ~/wipefs-sdb-0x00000438.bak.

AUTHOR
       Karel Zak <kzak AT redhat.com>

ENVIRONMENT
       Setting LIBBLKID_DEBUG=0xffff enables 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.ker‐
       nel.org/pub/linux/utils/util-linux/.



util-linux                                 October 2009                                 WIPEFS(8)