Subversion Repositories planix.SVN

.TH DD 1

.SH NAME

dd \- convert and copy a file

.SH SYNOPSIS

.B dd

[

.I option value

]

\&...

.SH DESCRIPTION

.I Dd\^

copies the specified input file

to the specified output with

possible conversions.

The standard input and output are used by default.

The input and output block size may be

specified to take advantage of raw physical I/O.

The options are

.TF "quietb\ \ \fIn

.PD 0.2v

.TP

.BI -if\  f

Open file

.I f

for input.

.TP

.BI -of\  f

Open file

.I f

for output.

.TP

.BI -ibs\  n\^

Set input block size to

.I n\^

bytes (default 512).

.TP

.BI -obs\  n\^

Set output block size (default 512).

.TP

.BI -bs\  n\^

Set both input and output block size,

superseding

.I ibs\^

and

.IR obs .

If no conversion is specified,

preserve the input block size instead of packing short blocks

into the output buffer.

This is particularly efficient since no in-core copy need be done.

.TP

.BI -cbs\  n\^

Set conversion buffer size.

.TP

.BI -skip\  n\^

Skip

.I n

input blocks before copying.

.TP

.BI -iseek\  n\^

Seek

.I n

blocks forward on input file

before copying.

.TP

.BI -iseekb\  n\^

Seek

.I n

bytes forward on input file before copying.

.TP

.BI -files\  n\^

Catenate

.I n

input files (useful only for magnetic tape or similar input device).

.TP

.BI -oseek\  n\^

Seek

.I n\^

blocks from beginning of output file before copying.

.TP

.BI -oseekb\  n\^

Seek

.I n\^

bytes from beginning of output file before copying.

.TP

.BI -count\  n\^

Copy only

.I n

input blocks.

.TP

.BI -trunc\  n\^

If

.I n

is

.BR 0 ,

open the output file without truncating it.

.TP

.BI -quiet\  n\^

If

.I n

is 1,

omit the summary of blocks transferred.

.HP

\fL-conv\ ascii\ \ \ \fRConvert

.SM EBCDIC

to

.SM ASCII.

.PD0

.RS "\w'\fLconv\ \fP'u"

.TP "\w'\fLunblock\ \ \fP'u"

.B ebcdic

Convert

.SM ASCII

to

.SM EBCDIC.

.TP

.B ibm

Like

.B ebcdic

but with a slightly different character map.

.TP

.B block

Convert variable-length

.SM ASCII

records (lines) to fixed length blocks.

.TP

.B unblock

Convert fixed length

.SM ASCII

blocks to variable-length lines.

.TP

.B lcase

Map alphabetics to lower case.

.TP

.B ucase

Map alphabetics to upper case.

.TP

.B swab

Swap every pair of bytes.

.TP

.B noerror

Do not stop processing on an error.

.TP

.B sync

Pad every input block to

.I  ibs\^

bytes.

.RE

.PD

.PP

.fi

Where sizes are specified,

a number of bytes is expected.

A number may end with

.L k

or

.LR b

to specify multiplication by

1024 or 512 respectively;

a pair of numbers may be separated by

.L x

to indicate a product.

Multiple conversions may be specified in the style:

.LR "-conv ebcdic,ucase" .

.PP

.L Cbs\^

is used only if

.LR ascii\^ ,

.LR unblock\^ ,

.LR ebcdic\^ ,

.LR ibm\^ ,

or

.L block\^

conversion is specified.

In the first two cases,

.I n

characters are copied into the conversion buffer, any specified

character mapping is done,

trailing blanks are trimmed and new-line is added

before sending the line to the output.

In the latter three cases, characters are read into the

conversion buffer and blanks are added to make up an

output block of size

.IR n .

If

.L cbs\^

is unspecified or zero, the

.LR ascii\^ ,

.LR ebcdic\^ ,

and

.L ibm\^

options convert the character set without changing the block

structure of the input file; the

.L unblock\^

and

.L block\^

options become a simple file copy.

.SH SOURCE

.B /sys/src/cmd/dd.c

.SH "SEE ALSO"

.IR cp (1)

.SH DIAGNOSTICS

.I Dd

reports the number of full + partial input and output

blocks handled.