NAME

       wipefs - wipe a signature from a device

SYNOPSIS

       wipefs [options] device...

       wipefs [--backup] -o offset device...

       wipefs [--backup] -a 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.  The default output is subject to change.  So  whenever  possible,
       you should avoid using default outputs in your scripts.  Always explicitly define expected
       columns by using --output columns-list in environments where a stable output is required.

       wipefs calls the BLKRRPART ioctl when it has erased a partition-table signature to  inform
       the  kernel  about the change. The ioctl is called as the last step and when all specified
       signatures from all specified devices are already erased.

       Note that some filesystems and some partition tables  store  more  magic  strings  on  the
       device  (e.g. FAT, ZFS, GPT).  The wipefs command (since v2.31) lists all the offset where
       a magic strings have been detected.

       When option -a is used, all magic strings that are visible for  libblkid  are  erased.  In
       this case the wipefs scans the device again after each modification (erase) until no magic
       string is found.

       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.

       -J, --json
              Use JSON output format.

       -n, --noheadings
              Do not print a header line.

       -O, --output list
              Specify which output columns to print.  Use --help to get a list of  all  supported
              columns.

       -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 /dev/sda*
              Prints information about sda and all partitions on sda.

       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
       https://www.kernel.org/pub/linux/utils/util-linux/.