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. This feature can be used to wipe
       content on partitions devices as well as partition table on a disk device, for example by
       wipefs -a /dev/sdc1 /dev/sdc2 /dev/sdc.

       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(3) 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 EXAMPLE 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.

       -J, --json
           Use JSON output format.

       --lock[=mode]
           Use exclusive BSD lock for device or file it operates. The optional argument mode can
           be yes, no (or 1 and 0) or nonblock. If the mode argument is omitted, it defaults to
           "yes". This option overwrites environment variable $LOCK_BLOCK_DEVICE. The default is
           not to use any lock at all, but it’s recommended to avoid collisions with udevd or
           other tools.

       -i, --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(2) 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).

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

       -V, --version
           Print version and exit.

ENVIRONMENT

       LIBBLKID_DEBUG=all
           enables libblkid(3) debug output.

       LOCK_BLOCK_DEVICE=<mode>
           use exclusive BSD lock. The mode is "1" or "0". See --lock for more details.

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.

AUTHORS

       Karel Zak <kzak@redhat.com>

SEE ALSO

       blkid(8), findfs(8)

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

AVAILABILITY

       The wipefs command is part of the util-linux package which can be downloaded from Linux
       Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.