NAME
	deadshred - override the contents of a device that may be broken

SYNOPSIS
	deadshred [-b blocksize] [-o offset] [-l length | -e postend]
	          [-rY] device [map-file] [< random-source]

DESCRIPTION
	The deadshred utility fills a file or block devices with
	nonsense data. The utility is designed specifically for
	erasing the content of failing hard disc drives, for this
	purpose, the deadshred utility will skip any section it fails
	to override and retries it later.

OPTIONS
	The following options are supported:

	-b blocksize
		Selects the initial block-size for writing on the
		first pass over the device.

	-e postend
		Position in the device to stop writing at. The byte
		indexed by the value postend will not be overwritten.

	-l length
		The number of bytes in the device to overwrite. If the
		-o option is unused (or the offset 0 is used), this is
		equivalent to the -e option, however the -o option is
		used, writing will stop at length bytes past offset.

	-o offset
		The index of the first byte in the device to overwrite.

	-r
		Start writing from the end instead of from the
		beginning on the first pass over the device.

	-Y
		Do not ask for confirmation.

OPERANDS
	The following operands are supported:

	device
		The file to override. Must be either a regular file or
		a block device.

	map-file
		If the file map-file exists and is non-empty, it
		specifies what sections in the file to overwrite;
		this file will be periodically, and upon exit,
		updated to remove parts that has been successfully
		overwritten. This file will be unlinked when it
		becomes empty.

STDIN
	Unless the standard input is a terminal device, it shall be an
	unless source of either random data or a particular byte to
	fill the device with.

NOTES
	While the deadshred utility is designed for block devices, it
	also works for regular files, however does not provide options
	that are useful for erasing regular files and is not designed
	to work with filesystems that use copy on write.

SEE ALSO
	dd(1), shred(1)