DD ( 1 ) USER COMMANDSDD ( 1 )


NAME

dd - convert and copy a file

SYNOPSIS

dd [ options ]

DESCRIPTION

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

OPTIONS

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.

SEE ALSO

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

IMPLEMENTATION

version

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

Glenn Fowler <glenn.s.fowler@gmail.com>
copyright

Copyright © 1989-2012 AT&T Intellectual Property
license

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