DD(1)							    DD(1)

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=	      input file name; standard input is default
       of=	      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  con-
		      version  is  specified,  it is particularly
		      efficient since no copy need be done
       cbs=n	      conversion buffer size
       skip=n	      skip n input records before starting copy
       files=n	      copy n files from (tape) input
       seek=n	      seek n records  from  beginning  of  output
		      file before copying
       count=n	      copy only n input records
       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 record 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 a product.

       Cbs is used only if ascii or ebcdic conversion  is  speci-
       fied.   In  the former case cbs characters are placed into
       the conversion buffer, converted to  ASCII,  and	 trailing
       blanks  trimmed and 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, and
       blanks added to make up an output record of size cbs.

       After completion, dd reports the number of whole and  par-
       tial input and output blocks.

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DD(1)							    DD(1)

       For  example,  to  read an EBCDIC tape blocked ten 80-byte
       EBCDIC card images per record into the ASCII file x:

	      dd     if=/dev/rmt0     of=x     ibs=800	   cbs=80
	      conv=ascii,lcase

       Note  the  use of raw magtape.  Dd is especially suited to
       I/O on the raw physical devices because it allows  reading
       and writing in arbitrary record sizes.

       To  skip	 over a file before copying from magnetic tape do
       (dd of=/dev/null; dd of=x) </dev/rmt0

SEE ALSO
       cp(1), tr(1)

DIAGNOSTICS
       f+p records in(out): numbers of full and	 partial  records
       read(written)

BUGS
       The  ASCII/EBCDIC conversion tables are taken from the 256
       character standard in the CACM Nov, 1968.  The `ibm'  con-
       version,	 while	less  blessed  as a standard, corresponds
       better to certain IBM print train conventions.	There  is
       no universal solution.

       Newlines are inserted only on conversion to ASCII; padding
       is done only on conversion to  EBCDIC.	These  should  be
       separate options.

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