| .\" Copyright 2009 by Karel Zak. All Rights Reserved. |
| .\" This file may be copied under the terms of the GNU Public License. |
| .\" |
| .TH WIPEFS 8 "December 2014" "util-linux" "System Administration" |
| .SH NAME |
| wipefs \- wipe a signature from a device |
| .SH SYNOPSIS |
| .B wipefs |
| .RB [ options ] |
| .IR device ... |
| .sp |
| .B wipefs |
| .RB [ \-\-backup ] |
| .B \-o |
| .I offset |
| .IR device ... |
| .sp |
| .B wipefs |
| .RB [ \-\-backup ] |
| .B \-a |
| .IR device ... |
| .SH DESCRIPTION |
| .B wipefs |
| can erase filesystem, raid or partition-table signatures (magic strings) from |
| the specified |
| .I device |
| to make the signatures invisible for libblkid. |
| .B 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 |
| .B \-\-output |
| .I columns-list |
| in environments where a stable output is required. |
| |
| .B 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 |
| .B wipefs |
| command (since v2.31) lists all the offset where a magic strings have been |
| detected. |
| |
| When option \fB-a\fR is used, all magic strings that are visible for libblkid are |
| erased. In this case the |
| .B wipefs |
| scans the device again after each modification (erase) until no magic string is found. |
| |
| Note that by default |
| .B wipefs |
| does not erase nested partition tables on non-whole disk devices. |
| For this the option \fB\-\-force\fR is required. |
| |
| .SH OPTIONS |
| .TP |
| .BR \-a , " \-\-all" |
| Erase all available signatures. The set of erased signatures can be |
| restricted with the \fB\-t\fR option. |
| .TP |
| .BR \-b , " \-\-backup" |
| Create a signature backup to the file $HOME/wipefs-<devname>-<offset>.bak. |
| For more details see the \fBEXAMPLES\fR section. |
| .TP |
| .BR \-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. |
| .TP |
| .BR \-h , " \-\-help" |
| Display help text and exit. |
| .TP |
| .BR \-J , " \-\-json" |
| Use JSON output format. |
| .TP |
| .BR \-n , " \-\-noheadings" |
| Do not print a header line. |
| .TP |
| .BR \-O , " \-\-output " \fIlist\fP |
| Specify which output columns to print. Use \-\-help to |
| get a list of all supported columns. |
| .TP |
| .BR -n , " \-\-no\-act" |
| Causes everything to be done except for the write() call. |
| .TP |
| .BR \-o , " \-\-offset " \fIoffset\fP |
| Specify the location (in bytes) of the signature which should be erased from the |
| device. The \fIoffset\fR number may include a "0x" prefix; then the number will be |
| interpreted as a hex value. It is possible to specify multiple \fB-o\fR options. |
| .sp |
| The \fIoffset\fR 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. |
| .TP |
| .BR \-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'. |
| .TP |
| .BR \-q , " \-\-quiet" |
| Suppress any messages after a successful signature wipe. |
| .TP |
| .BR \-t , " \-\-types " \fIlist\fP |
| 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). |
| .TP |
| .BR -V , " \-\-version" |
| Display version information and exit. |
| .SH EXAMPLES |
| .TP |
| .B wipefs /dev/sda* |
| Prints information about sda and all partitions on sda. |
| .TP |
| .B 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. |
| .TP |
| .B 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. |
| .SH AUTHOR |
| Karel Zak <kzak@redhat.com> |
| .SH ENVIRONMENT |
| .IP LIBBLKID_DEBUG=all |
| enables libblkid debug output. |
| .SH SEE ALSO |
| .BR blkid (8), |
| .BR findfs (8) |
| .SH AVAILABILITY |
| The wipefs command is part of the util-linux package and is available from |
| https://www.kernel.org/pub/linux/utils/util-linux/. |