WIPEFS(8)						       System Administration							 WIPEFS(8)

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  sub-
       ject  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.

       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"  pre-
	      fix; 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 individ-
	      ual 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)