www.LinuxHowtos.org

WIPEFS

Section: System Administration (8)
Updated: December 2014
Index Return to Main Contents

NAME

wipefs - wipe a signature from a device

SYNOPSIS

wipefs [-ahnpqtV] [-o offset] 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.

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. The wipefs command lists only the first offset where a magic string has been detected. The device is not scanned for additional magic strings for the same filesystem. It is possible that after a wipefs -o offset the same filesystem or partition table will still be visible because of another magic string on another offset. The option --no-act is also affected by this behavior and only the first magic string for the filesystem is reported.

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.
-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 --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.

AVAILABILITY

The wipefs command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.