dd.1 (2010 09)

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dd(1) dd(1)

NAME

dd - convert, reblock, translate, and copy a (tape) ﬁle

SYNOPSIS

dd [option=value ] ...

DESCRIPTION

dd copies the speciﬁed input ﬁle to the speciﬁed output ﬁle with possible conversions. The standard

input and output are used by default. Input and output block size can be speciﬁed to take advantage of

raw physical I/O. Upon completion, dd reports the number of whole and partial input and output

records.

Options

dd recognizes the following option =value pairs:

if=file Input ﬁle name; default is standard input.

of=file Output ﬁle name; default is standard output. The output ﬁle is created using the

same owner and group used by creat()

ibs=n Input block size is n bytes; default is 512.

obs=n Output block size is n bytes; default is 512.

bs=n Set both input and output block size to the same size, superseding ibs and obs

This option is particularly efﬁcient if no conversion (

conv option) is speciﬁed,

because no in-core copy is necessary.

cbs=n Conversion buffer size is n bytes.

skip=n Skip n input blocks before starting copy.

iseek=n Skip n input blocks before starting copy. (This is an alias for the skip option.)

seek=n Skip n blocks from beginning of output ﬁle before copying.

oseek=n Skip n blocks from beginning of output ﬁle before copying. (This is an alias for the

seek option.)

count=n Copy only n input blocks.

files=n Copy and concatenate n input ﬁles. This option should be used only when the input

ﬁle is a magnetic tape device.

conv=value [,value ...]

Where value s are comma-separated symbols from the following list.

ascii Convert EBCDIC to ASCII.

ebcdic Convert ASCII to EBCDIC.

ibm Convert ASCII to EBCDIC using an alternate conversion table.

The

ascii, ebcdic, and ibm values are mutually exclusive.

block Convert each newline-terminated or end-of-ﬁle-terminated input

record to a record with a ﬁxed length speciﬁed by cbs. Any

newline character is removed, and space characters are used to

ﬁll the block to size cbs. Lines that are longer than cbs are

truncated; the number of truncated lines (records) is reported

(see DIAGNOSTICS below).

The

block and unblock values are mutually exclusive.

unblock Convert ﬁxed-length input records to variable-length records.

For each input record, cbs bytes are read, trailing space char-

acters are deleted, and a newline character is appended.

lcase Map upper-case input characters to the corresponding lower-

case characters.

The

lcase and ucase values are mutually exclusive.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (4 pages)

PAGE 1
dd(1) dd(1) NAME dd - convert, reblock, translate, and copy a (tape) file SYNOPSIS dd [option =value ] ... DESCRIPTION dd copies the specified input file to the specified output file with possible conversions. The standard input and output are used by default. Input and output block size can be specified to take advantage of raw physical I/O. Upon completion, dd reports the number of whole and partial input and output records.
PAGE 2
dd(1) A dA dd(1) ucase Map lower-case input characters to the corresponding uppercase characters. swab Swap every pair of input bytes. noerror Do not stop processing on an input error. If the sync conversion symbol is also specified, missing input is replaced with null bytes and processed normally; otherwise, the input block is omitted from the output. notrunc Do not truncate existing output file. Blocks in the output file not overwritten by this invocation of dd are preserved.
PAGE 3
dd(1) dd(1) dd if=/dev/rmt/c0t0d0BEST of=x ibs=800 cbs=80 conv=ascii,lcase Note the use of the raw magnetic tape device file. dd is especially suited to I/O on raw physical devices because it allows reading and writing in arbitrary block sizes. WARNINGS Some devices, such as 1/2-inch magnetic tapes, are incapable of seeking. Such devices may be positioned prior to running dd by using mt(1) or some other appropriate command. The skip, seek, iseek and oseek options do work for such devices.
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(Notes) A (Notes) dA 4 Hewlett-Packard Company −1− HP-UX 11i Version 3: September 2010