dd man page on HP-UX

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dd(1)									 dd(1)

       dd - convert, reblock, translate, and copy a (tape) file

       [optionvalue] ...

       copies  the specified input file to the specified output file with pos‐
       sible conversions.  The standard input and output are used by  default.
       Input  and  output block size can be specified to take advantage of raw
       physical I/O.  Upon completion, reports the number of whole and partial
       input and output records.

       recognizes the following pairs:

	      Input file name; default is standard input.

	      Output file name; default is standard output.
			     The  output  file is created using the same owner
			     and group used by

	      Input block size is
			     n bytes; default is 512.

	      Output block size is
			     n bytes; default is 512.

	      Set both input and output block size to the same size, supersed‐
			     and  This	option is particularly efficient if no
			     conversion is specified, because no in-core  copy
			     is necessary.

	      Conversion buffer size is
			     n bytes.

	      Skip	     n input blocks before starting copy.

	      Skip	     n input blocks before starting copy.  (This is an
			     alias for the option.)

	      Skip	     n blocks from beginning  of  output  file	before

	      Skip	     n	blocks	from  beginning	 of output file before
			     copying.  (This is an alias for the option.)

	      Copy only	     n input blocks.

	      Copy and concatenate
			     n input files.  This option should be  used  only
			     when the input file is a magnetic tape device.

	      Where	     values  are comma-separated symbols from the fol‐
			     lowing list.

			     Convert EBCDIC    to ASCII.

			     Convert ASCII     to EBCDIC.

			     Convert ASCII to EBCDIC using an  alternate  con‐
			     version table.

					       The  and	 values	 are  mutually

			     Convert each newline-terminated  or  end-of-file-
			     terminated input record
					       to a record with a fixed length
					       specified by Any newline	 char‐
					       acter  is  removed,  and	 space
					       characters are used to fill the
					       block  to  size	Lines that are
					       longer than are truncated;  the
					       number	of   truncated	 lines
					       (records)  is   reported	  (see

					       The  values are mutually exclu‐

			     Convert fixed-length input records	 to  variable-
			     length records.
					       For  each  input	 record, bytes
					       are read, trailing space	 char‐
					       acters  are deleted, and a new‐
					       line character is appended.

			     Map upper-case input  characters  to  the	corre‐
			     sponding lower-case characters.

					       The  values are mutually exclu‐

			     Map lower-case input  characters  to  the	corre‐
			     sponding upper-case characters.

			     Swap every pair of input bytes.

			     Do not stop processing on an input error.
					       If  the	conversion  symbol  is
					       also specified,	missing	 input
					       is replaced with null bytes and
					       processed normally;  otherwise,
					       the input block is omitted from
					       the output.

			     Do not truncate existing output file.
					       Blocks in the output  file  not
					       overwritten  by this invocation
					       of are preserved.

			     Pad every input block to size
					       If is also specified, pad  with
					       space   characters;  otherwise,
					       pad with null bytes.

       Where sizes are required, n indicates a numerical value in bytes.  Num‐
       bers can be specified using the forms:

	      n		for n bytes
	      for	n Kbytes (n × 1024),
	      for	n blocks (n × 512), or
	      for	n words (n × 2).

       To indicate a product, use to separate number pairs.

       The  option  is	used  when or conversion is specified.	In case of cbs
       characters are placed into the conversion buffer, converted  to	ASCII,
       trailing	 blanks are trimmed, and a newline is added before sending the
       line to the output.  In case of ASCII characters are read into the con‐
       version buffer, converted to EBCDIC, and blanks are added to make up an
       output block of size cbs.

   International Code Set Support
       Single- and multi-byte character code sets are supported.

   Environment Variables
       The following environment variables affect execution of

       determines the locale when and a corresponding variable (beginning with
       do not specify a locale.

       determines  the	locale used to override any values set by or any envi‐
       ronment variables beginning with

       The variable determines the locale for the interpretation of  sequences
       of bytes of text data as characters (single-byte/multi-byte characters,
       upper-case/lower-case characters).

       The variable determines the language in which messages are written.

       Exit values are:

	      Successful completion.
	      Error condition occurred.

       Upon completion, reports the number of input and output records:

	      Number of full and partial blocks read.
	      Number of full and partial blocks written.

       When is specified and there is at least one truncated block, the number
       of truncated records is also reported:

       Read  an	 EBCDIC	 tape blocked ten 80-byte EBCDIC card images per block
       into an ASCII file named

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

       Some devices, such as 1/2-inch magnetic tapes, are incapable  of	 seek‐
       ing.  Such devices may be positioned prior to running by using mt(1) or
       some other appropriate command.	The options do work for such  devices.
       However,	 skipping  blocks  using these options is slow on devices that
       cannot seek, since the blocks must actually  be	read  to  get  to  the
       desired position on the tape.

       ASCII and EBCDIC conversion tables are taken from the 256-character ACM
       standard, Nov, 1968.  The conversion, while less widely accepted	 as  a
       standard,  corresponds  better  to certain IBM print train conventions.
       There is no universal solution.

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

       If  or  refers to a raw disk, should always be a multiple of the sector
       size of the disk.  By default, is 512 bytes.  If the sector size of the
       disk  is different from 512 bytes, should be specified using a multiple
       of sector size.	The character special (raw) device file should	always
       be used for devices.

       It  is  entirely	 up  to the user to insure there is enough room in the
       destination file, file system and/or device to contain the output since
       cannot pre-determine the required space after conversion.

       cp(1), mt(1), tr(1), disk(7), mt(7).


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