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

block convert variable length records to fixed length

unblock convert fixed length records to variable length

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. 

cbs is used only if conv=ascii, conv=unblock, conv=ebcdic, or conv=block is specified.  In the first two cases, 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 two cases, 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)

September 02, 1992