-.\" -*- nroff -*-
.\" Copyright 2009 by Karel Zak. All Rights Reserved.
.\" This file may be copied under the terms of the GNU Public License.
.\"
-.TH WIPEFS 8 "October 2009" "Linux" "MAINTENANCE COMMANDS"
+.TH WIPEFS 8 "December 2014" "util-linux" "System Administration"
.SH NAME
-wipefs \- wipe a filesystem signature from a device
+wipefs \- wipe a signature from a device
.SH SYNOPSIS
.B wipefs
-.RB [ \-ahnp ]
+.RB [ \-ahnpqtV ]
.RB [ \-o
.IR offset ]
-.I device
+.IR device ...
.SH DESCRIPTION
.B wipefs
-allows to erase filesystem or raid signatures (magic strings) from the
+can erase filesystem, raid or partition-table signatures (magic strings) from
+the specified
.I device
-to make the device invisible for libblkid.
+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, \fBwipefs\fR lists all visible filesystems
+and the offsets of their basic signatures.
+
.B wipefs
-does not erase the whole filesystem or any other data from the device.
-When used without options -a or -o, it lists all visible filesystems and offsets
-of their signatures.
+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
+.B 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 \fBwipefs -o \fIoffset\fR the same filesystem or partition
+table will still be visible because of another magic string on another offset.
+
+When option \fB-a\fR is used, all magic strings that are visible for libblkid are
+erased.
+
+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
-.IP "\fB\-a, \-\-all\fP"
-Erase all available signatures.
-.IP "\fB\-h, \-\-help\fP"
-Print help and exit.
-.IP "\fB\-n, \-\-no\-act\fP"
+.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 -n , " \-\-no\-act"
Causes everything to be done except for the write() call.
-.IP "\fB\-o, \-\-offset\fP \fIoffset\fP
-Specifies location (in bytes) of the signature which should be erased from the
-device. The offset number may include a "0x" prefix, and then the number will be
-read as a hex value. It is possible to specify multiple -o options.
-.IP "\fB\-p, \-\-parsable\fP"
-Print out in parsable instead of printable format. Encode all potentially unsafe
+.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
+.BR "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
+.BR "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 AVAILABILITY
-The wipefs command is part of the util-linux-ng package and is available from
-ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
+Karel Zak <kzak@redhat.com>
+.SH ENVIRONMENT
+.IP LIBBLKID_DEBUG=all
+enables libblkid debug output.
.SH SEE ALSO
-.BR blkid (8)
+.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/.
projects / thirdparty / util-linux.git / blobdiff