dd(1M)                                                               dd(1M)


   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 sizes 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 n bytes (default 512)
         bs=n            set both input and output block size, superseding ibs
                         and obs; also, if no conversion is specified,
                         preserve the input block size instead of packing
                         short blocks into the output buffer (this is
                         particularly efficient since no in-core copy need be
                         done)
         cbs=n           conversion buffer size (logical record length)
         files=n         copy and concatenate n input files before terminating
                         (makes sense only where input is a magnetic tape or
                         similar device)
         skip=n          skip n input blocks before starting copy (appropriate
                         for magnetic tape, where iseek is undefined)
         iseek=n         seek n blocks from beginning of input file before
                         copying (appropriate for disk files, where skip can
                         be incredibly slow)
         oseek=n         seek n blocks from beginning of output file before
                         copying
         seek=n          identical to oseek, retained for backward
                         compatibility
         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 new-line terminated ASCII records to fixed
                         length
              unblock    convert fixed length ASCII records to new-line
                         terminated records
              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 (limit of 5
                         consecutive errors)




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   dd(1M)                                                               dd(1M)


              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 ascii, unblock, ebcdic, ibm, or block conversion
         is specified.  In the first two cases, cbs characters are copied into
         the conversion buffer, any specified character mapping is done,
         trailing blanks are trimmed and a 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 cbs.  If cbs is unspecified or zero, the ascii,
         ebcdic, and ibm options convert the character set without changing
         the block structure of the input file; the unblock and block options
         become a simple file copy.

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

   EXAMPLE
         This command will read an EBCDIC tape blocked ten 80-byte EBCDIC card
         images per tape block into the ASCII file x:

         dd  if=/dev/rmt/0h  of=x  ibs=800  obs=8k  cbs=80  conv=ascii,lcase

         Note the use of raw magnetic tape.  dd is especially suited to I/O on
         the raw physical devices because it allows reading and writing in
         arbitrary block sizes.

   SEE ALSO
         cp(1)

   NOTES
         Do not use dd to copy files between filesystems having different
         block sizes.

         Using a  blocked device to copy a file will result in extra nulls
         being added to the file to pad the final block to the block boundary.

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








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