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/.

util-linux                                        December 2014                                        WIPEFS(8)