glenda.party
term% ls -F
term% pwd
$home/manuals/plan9_2nd/1/dd
term% cat index.txt
DD(1)                       General Commands 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 possi‐
       ble 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, 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  Set conversion buffer size.

       -skip n Skip n input records before copying.

       -iseek n
               Seek n records forward on input file before copying.

       -files n
               Catenate  n input files (useful only for magnetic tape or simi‐
               lar input device).

       -oseek 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      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 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  or  to specify multiplication by 1024 or 512 respectively; a
       pair of numbers may be separated by to indicate  a  product.   Multiple
       conversions may be specified in the style:

       is  used only if or conversion is specified.  In the first two cases, n
       characters are copied into the conversion buffer, any specified charac‐
       ter  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 is unspecified or zero, the and
       options  convert the character set without changing the block structure
       of the input file; the and options become a simple file copy.

SOURCE
       /sys/src/cmd/dd.c

SEE ALSO
       cp(1)

DIAGNOSTICS
       Dd reports the number of full + partial input and  output  blocks  han‐
       dled.



                                                                         DD(1)