dd - convert and copy a file

dd copies an input file to an output file with optional conversions. The standard input and output are used by default. Input and output block sizes can be specified to take advantage of physical io limitations. Options are of the form name=value and may be specified with 0, 1, or 2 leading `-' characters.

A number argument may be a scaled number with optional trailing multipliers of the form `* number', `x number' or `X number'. Scale suffixes may be one of:

b|B

512

k|K

1000

ki|Ki

1024

m|M

1000000

mi|Mi

1048576

g|G

1000000000

gi|Gi

1073741824

t|T

1000000000000

ti|Ti

1099511627776

p|P

1000000000000000

pi|Pi

1125899906842624

e|E

1000000000000000000

ei|Ei

1152921504606846976

bs=number

Input and output block size.

cbs=number

Conversion buffer size (logical record length).

conv=conversion

Convert input. conversion may be one of:

a2e

ascii to ebcdic

a2i

ascii to ibm

a2n

ascii to native

a2o

ascii to open edition ebcdic

ascii

ebcdic to ascii

block

newline-terminated ascii to fixed record length

e2a

ebcdic to ascii

ebcdic

equivalent to a2e

i2a

ibm to ascii

ibm

ascii to ibm ebcdic

ignerror

continue processing after errors

ispecial

currently ignored

lcase

to lower case

n2a

native to ascii

noerror

stop processing only after 5 consecutive errors

notrunc

do not truncate pre-existing output files

o2a

open edition ibm to ascii

ospecial

currently ignored

swab

swap byte pairs

sync

Pad each input block to ibs. Pad with spaces if conv=block or conv=unblock, otherwise pad with nulls.

ucase

to upper case

unblock

fixed-length records to newline-terminated records

count=number

Copy only number input blocks.

from=codeset

Convert from codeset to the to=codeset or the local default. codeset names are matched by left-anchored case-insensitive ksh(1) patterns. codeset may be one of:

a|ascii|?(iso)?(-)646|?(iso)?(-)8859|latin

8 bit ascii

e|ebcdic?(-)?([1e])

X/Open ebcdic

o|ebcdic?(-)[3o]|?(cp|ibm)1047|open?(-)edition

mvs OpenEdition ebcdic

h|ebcdic?(-)h|?(cp|ibm)?(00)37|[oa]s?(/-)400

ibm OS/400 AS/400 ebcdic

s|ebcdic?(-)s|siemens|posix-bc

siemens posix-bc ebcdic

i|ebcdic?(-)[2i]|ibm

X/Open ibm ebcdic (not idempotent)

m|ebcdic?(-)m|mvs

mvs ebcdic

u|ebcdic?(-)(u|mf)|microfocus

microfocus cobol ebcdic

n|native|local

native code set

un|unicode|utf

multibyte 8-bit unicode

um|ume|utf?(-)7

multibyte 7-bit unicode

(big|euc)*

euc family

dos?(-)?(855)

dos code page

ucs?(-)?(2)?(be)|utf-16?(be)

unicode runes

ucs?(-)?(2)le|utf-16le

little endian unicode runes

ibs=number

Input block size.

if=file

The input file name; standard input is the default.

iseek=number

Seek number blocks from the beginning of the input file before copying.

obs=number

Output block size.

of=file

The output file name; standard output is the default.

oseek|seek=number

Seek number blocks from the beginning of the output file before copying.

silent

silent does not print the total number of io blocks on exit.

skip=number

Skip number blocks before reading. Seek is used if possible, otherwise the blocks are read and discarded.

swap=number

Swap bytes acording to the inclusive or of: 1-byte, 2-short, 4-long, 8-quad, etc.

to=codeset

Convert to codeset from the from=codeset or the local default. See from for codeset names.

cp(1), iconv(1), pax(1), tr(1), seek(2)

version

dd (AT&T Research) 2011-04-21

author

Glenn Fowler <gsf@research.att.com>

copyright

Copyright © 1989-2012 AT&T Intellectual Property

license

http://www.eclipse.org/org/documents/epl-v10.html