DD(1M) (Essential Utilities) DD(1M)
NAME
dd - convert and copy a file
SYNOPSIS
dd [option=value] ...
DESCRIPTION
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.
option values
if=file input file name; standard input is default
of=file output file name; standard output is default
ibs=n input block size n bytes (default 512)
obs=n output block size (default 512)
bs=n set both input and output block size,
superseding ibs and obs; also, if no
conversion is specified, it is particularly
efficient since no in-core copy need be done
cbs=n conversion buffer size
skip=n skip n input blocks before starting copy
seek=n seek n blocks from beginning of output file
before copying
count=n copy only n input blocks
conv=ascii convert EBCDIC to ASCII
ebcdic convert ASCII to EBCDIC
ibm slightly different map of ASCII to EBCDIC
lcase map alphabetics to lower case
ucase map alphabetics to upper case
swab swap every pair of bytes
noerror do not stop processing on an error
sync pad every input block to ibs
... , ... several comma-separated conversions
Where sizes are specified, a number of bytes is expected. A
number may end with k, b, or w to specify multiplication by
1024, 512, or 2, respectively; a pair of numbers may be
separated by x to indicate multiplication.
Page 1 May 1989
DD(1M) (Essential Utilities) DD(1M)
cbs is used only if conv=ascii or conv=ebcdic is specified.
In the former case, cbs characters are placed into the
conversion buffer (converted to ASCII). Trailing blanks are
trimmed and a new-line added before sending the line to the
output. In the latter case, ASCII characters are read into
the conversion buffer (converted to EBCDIC). Blanks are
added to make up an output block of size cbs.
After completion, dd reports the number of whole and partial
input and output blocks.
DIAGNOSTICS
f+p blocks in(out) numbers of full and partial blocks
read(written)
Page 2 May 1989