DD(1)                   GENIX Programmer's Manual                   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 pos-
           sible  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 conversion 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        skip n input files before starting copy
           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
                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 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, unblock, ebcdic, ibm, or block conversion
           is  specified.   In  the  first two cases, cbs characters are placed
           into the conversion buffer, any specified character mapping is done,
           trailing  blanks  trimmed and new-line added before sending the line
           to the output.  In the latter three cases, characters are read  into
           the  conversion buffer, and blanks added to make up an output record
           of size cbs.





      Printed 11/16/83                                                        1

      DD(1)                   GENIX Programmer's Manual                   DD(1)



           After completion, dd reports the number of whole and  partial  input
           and output blocks.

           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 arbi-
           trary record sizes.

      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' conversion, while less
           blessed as a standard, corresponds better to certain IBM print train
           conventions.  There is no universal solution.






























      Printed 11/16/83                                                        2