man(1) Manual page archive

     DD(1)                                                       DD(1)

          dd - convert and copy a file

          dd [ option value ] ...

          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.  The
          options are

          -if f    Open file f for input.

          -of f    Open file f for output.

          -ibs n   Set input block size to n bytes (default 512).

          -obs n   Set output block size (default 512).

          -bs n    Set both input and output block size, superseding
                   ibs and obs. If no conversion is specified, pre-
                   serve the input block size instead of packing short
                   blocks into the output buffer.  This is particu-
                   larly efficient since no in-core copy need be done.

          -cbs n   Set conversion buffer size.

          -skip n  Skip n input records before copying.

          -iseek n Seek n records forward on input file before copy-

          -files n Catenate n input files (useful only for magnetic
                   tape or similar input device).

          -oseek n Seek n records from beginning of output file before

          -count n Copy only n input records.

          -conv ascii    Convert EBCDIC to ASCII.
                ebcdic   Convert ASCII to EBCDIC.
                ibm      Like ebcdic but with a slightly different
                         character map.
                block    Convert variable length ASCII records to
                         fixed length.
                unblock  Convert fixed length ASCII records to

     DD(1)                                                       DD(1)

                         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 bytes.

          Where sizes are specified, a number of bytes is expected.  A
          number may end with `k' or `b' to specify multiplication by
          1024 or 512 respectively; a pair of numbers may be separated
          by `x' to indicate a product.  Multiple conversions may be
          specified in the style: `-conv ebcdic,ucase'.

          `Cbs' is used only if `ascii', `unblock', `ebcdic', `ibm',
          or `block' conversion is specified.  In the first two cases,
          n characters are copied into the conversion buffer, any
          specified character mapping is done, trailing blanks are
          trimmed and new-line is added before sending the line to the
          output.  In the latter three cases, characters are read into
          the conversion buffer and blanks are added to make up an
          output record of size n. If `cbs' is unspecified or zero,
          the `ascii', `ebcdic', and `ibm' options convert the charac-
          ter set without changing the block structure of the input
          file; the `unblock' and `block' options become a simple file


          Dd reports the number of full + partial input and output
          blocks handled.

          cat(1), cp(1)