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dd                           Command                           dd




File conversion

dddd [_o_p_t_i_o_n=_v_a_l_u_e] ...

dd copies  an input file to an output  file, while performing re-
quested conversions.  Options include case and character set con-
versions, byte  swapping conversion for other  machines, and dif-
ferent input  and output buffer  sizes.  dd can be  used with raw
disk files  or raw tape  files to do efficient  copies with large
block  (record) sizes.   Read and write  requests can  be changed
with the bs option described below.

The  following list  gives  each available  option.  Any  numbers
which specify  block sizes  or seek  positions may be  written in
several ways.  A  number followed by w, b, or  k is multiplied by
two  (for words),  512 (for  blocks),  or 1,024  (for kilobytes),
respectively, to  obtain the size in bytes.  A  pair of such num-
bers separated  by x is multiplied together  to produce the size.
All buffer sizes default to 512 bytes if not specified.

bbss=_n    Set the size of the buffer for both input and output to n
        bytes.

ccbbss=_n   Set the conversion buffer size to n bytes (used only with
        character set conversions between ASCII and EBCDIC).

ccoonnvv=_l_i_s_t
        Perform  conversions  specified  by  the  comma-separated
        list, which may include the following:

        aasscciiii          Convert EBCDIC to ASCII.
        eebbccddiicc         Convert ASCII to EBCDIC.
        iibbmm            Convert ASCII to EBCDIC, IBM flavor.
        llccaassee          Convert upper case to lower.
        nnooeerrrroorr        Continue processing on I/O errors.
        sswwaabb           Swap every pair of bytes before output.
        ssyynncc           Pad input buffers with 0 bytes to size of iibbss.
        uuccaassee          Convert lower case to upper.


ccoouunntt=_n
        Copy a maximum of n input records.

ffiilleess=_n
        Copy a  maximum of  n input  files (useful  for multifile
        tapes).

iibbss=_n   Set the  input buffer size  to n (normally  used if input
        and output blocking sizes are to be different).

iiff=_f_i_l_e
        Open file for input;  the standard input is  used when no
        if= option is given.



COHERENT Lexicon                                           Page 1




dd                           Command                           dd



oobbss=_n   Set the output buffer size to n.

ooff=_f_i_l_e
        Open file for output; the standard output is used when no
        of= option is given.

sseeeekk=_n  Seek to position  n bytes into the  output before copying
        (does  not  work  on stream  data  such  as  tapes,  com-
        munications devices, and pipes).

sskkiipp=_n  Read and discard the first n input records.

***** See Also *****

ASCII, commands, conv, cp, tape, tr

***** Diagnostics *****

The command  reports the number of full  and partial buffers read
and written upon completion.

***** Notes *****

Because  of differing interpretations  of EBCDIC,  especially for
certain more  exotic graphic characters such  as braces and back-
slash,  no one  conversion  table will  be adequate  for all  ap-
plications.   The ebcdic  table is the  American Standard  of the
Business  Equipment  Manufacturers  Association.  The  ibm  table
seems to be more practical for line printer codes at many IBM in-
stallations.



























COHERENT Lexicon                                           Page 2

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