wipefs — wipe a signature from a device
wipefs [options]
device...
wipefs [−−backup] −o offset device...
wipefs [−−backup] −a device...
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 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.
−a,
−−allErase all available signatures. The set of erased
signatures can be restricted with the −t option.
−b,
−−backupCreate a signature backup to the file
$HOME/wipefs-<devname>-<offset>.bak. For
more details see the EXAMPLE section.
−f,
−−forceForce erasure, even if the filesystem is mounted. This is required in order to erase a partition-table signature on a block device.
−h,
−−helpDisplay help text and exit.
−J,
−−jsonUse 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,
−−noheadingsDo not print a header line.
−O,
−−output listSpecify which output columns to print. Use −−help to get a list of all supported columns.
−n,
−−no−actCauses everything to be done except for the write() call.
−o,
−−offset offsetSpecify 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,
−−parsablePrint out in parsable instead of printable format. Encode all potentially unsafe characters of a string to the corresponding hex value prefixed by '\x'.
−q,
−−quietSuppress any messages after a successful signature wipe.
−t,
−−types listLimit 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,
−−versionDisplay version information and exit.
LIBBLKID_DEBUG=allenables libblkid debug output.
LOCK_BLOCK_DEVICE=<mode>use exclusive BSD lock. The mode is "1" or "0". See
−−lock for more
details.
Prints information about sda and all partitions on sda.
Erases all signatures from the device /dev/sdb and creates a signature backup file ~/wipefs-sdb-<offset>.bak for each signature.
Restores an ext2 signature from the backup file ~/wipefs-sdb-0x00000438.bak.