DD(1)                   COMMAND REFERENCE                   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.

     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 or * to indicate a product.

     Cbs is used only if ascii, unblock, ebcdic, ibm, or block
     conversion is specified.  In the first two cases, cbs
     characters are placed into the conversion buffer, any
     specified character mapping is done, trailing blanks trimmed
     and new-line added before sending the line to the output.
     In the latter three cases, characters are read into the
     conversion buffer, and blanks added to make up an output
     record of size cbs.

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

OPTIONS
     bs=n
        set both input and output block size, superseding ibs and
        obs; also, if no conversion is specified, it is
        particularly efficient since no copy need be done

     cbs=n
        conversion buffer size

     conv=ascii
            convert EBCDIC to ASCII

          ebcdic
            convert ASCII to EBCDIC

          ibm
            slightly different map of ASCII to EBCDIC

          block
            convert variable length records to fixed length

          unblock
            convert fixed length records to variable length



Printed 4/6/89                                                  1

DD(1)                   COMMAND REFERENCE                   DD(1)



          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

     count=n
        copy only n input records

     files=n
        copy n input files before terminating (makes sense only
        where input is a magtape or similar device).

     ibs=n
        input block size n bytes (default 512)

     if=
        input file name; standard input is default

     obs=n
        output block size (default 512)

     of=
        output file name; standard output is default

     seek=n
        seek n records from beginning of output file before
        copying

     skip=n
        skip n input records before starting copy

     sync
        pad every input record to ibs

EXAMPLES
     For example, to read an EBCDIC tape blocked ten 80-byte
     EBCDIC card images per record into the ASCII file x:





Printed 4/6/89                                                  2

DD(1)                   COMMAND REFERENCE                   DD(1)



          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.

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

RETURN VALUE
     [NO_ERRS]      Command completed without error.

     [USAGE]        Incorrect command line syntax. Execution
                    terminated.

     [NP_WARN]      An error warranting a warning message
                    occurred. Execution continues.

     [NP_ERR]       An error occurred that was not a system
                    error.  Execution terminated.

     [P_WARN]       A system error occurred. Execution continues.
                    See intro(2) for more information on system
                    errors.

     [P_ERR]        A system error occurred. Execution
                    terminated.  See intro(2) for more
                    information on system errors.

CAVEATS
     The ASCII/EBCDIC conversion tables are taken from the 256
     character standard in the CACM Nov, 1968.  The `ibm'
     conversion, while less blessed as a standard, corresponds
     better to certain IBM print train conventions.  There is no
     universal solution.

SEE ALSO
     cp(1) and tr(1).
















Printed 4/6/89                                                  3

%%index%%
na:192,80;
sy:272,159;
de:431,1335;
op:1766,659;2689,1013;
ex:3702,212;4178,254;
di:4432,314;
rv:4746,836;
ca:5582,353;
se:5935,126;
%%index%%000000000166