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, super-
                         seding 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        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 sepa-
          rated by x to indicate a product.

          Cbs is used only if ascii or ebcdic conversion is specified.
          In the former case cbs characters are placed into the con-
          version 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.

     DD(1)                                                       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 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' conver-
          sion, while less blessed as a standard, corresponds better
          to certain IBM print train conventions.  There is no univer-
          sal solution.

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