.TH ECP 1
.SH NAME
ecp \- fast copy, handling errors
.SH SYNOPSIS
.in +.5i
.ti -.5i
.B ecp
[
.B \-bcprvZ
] [
.B \-B
.I block-size
] [
.B \-e
.I max-errors
] [
.B \-i
.I issect
] [
.B \-o
.I ossect
] [
.B \-s
.I sector-size
]
.I sectors
.I input
.I output
.SH DESCRIPTION
.I Ecp
copies
.I sectors
disk sectors of the specified
.I input
file to the specified
.I output
file.
.I Ecp
copies multiple sectors (a `block') at a time for speed.
When
.I ecp
encounters an I/O error,
it transfers the current block again,
assuming the file is seekable,
one sector at a time,
prints the sector number(s) of the error(s),
and continues copying.
.PP
Options are:
.TP 4
.B \-b
reblock
.IR input
on short reads;
this was used mainly when reading a pipe on standard input
on 4.2+BSD systems.
.TP
.B \-B
sets the block size (16,384 bytes by default) to
.IR block-size .
.TP
.B \-c
ask for confirmation on
.B /dev/cons
before starting the copy.
.TP
.B \-e
sets a maximum number of consecutive I/O errors to permit
at the beginning of the copy before quitting to
.IR max-errors .
Lots of consecutive errors may indicate a deeper problem,
such as missing media.
By default there is no limit.
.TP
.B \-i
seeks to sector
.I issect
(assuming zero-origin)
before beginning input.
.TP
.B \-o
seeks to sector
.I ossect
(assuming zero-origin)
before beginning output.
.TP
.B \-p
print reassuring progress reports;
helpful mainly when dealing with cranky hardware.
.TP
.B \-r
copy sector groups in reverse order,
assuming the files are seekable;
this is most useful when
.I input
and
.I output
overlap.
.TP
.B \-s
sets the sector size (512 bytes by default) to
.IR sector-size .
.TP
.B \-v
verify the copy by rereading the
.I input
and
.I output
files after copying all sectors.
This is intended to force the disk to deliver the actual
data written on it rather than some cached copy.
The locations of any differences are printed.
.TP
.B \-Z
`Swizzle' the input: stir the bits around in some fashion.
Intended for diagnosing bad disks by copying a disk to itself
a few times with swizzling on (to defeat caching in operating systems
or disk controllers).
.SH "SEE ALSO"
.I fcp
in
.IR cp (1),
.IR dd (1),
.IR dup (3)
.SH BUGS
.BR \-i ,
.BR \-o ,
.BR \-r ,
.B \-v
and error retries only work on devices capable of seeking.
.PP
The set of options reflects decades of experience
dealing with troublesome hardware.
.PP
If the input file is a tape and
the last record on the tape before a file mark is less than
.I blocksize
bytes long,
then
.I ecp
will read through past the file mark and into the next file.