SysIII/usr/src/man/man1/dd.1

.TH DD 1
.SH NAME
dd \- convert and copy a file
.SH SYNOPSIS
.B dd
[option=value] ...
.SH DESCRIPTION
.I 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.
.PP
.br
.ns
.TP "\w'\fBconv=.\|.\|.\ ,\ .\|.\|.\ \ \fP'u"
.I option\^
.I values\^
.br
.ns
.TP
.BI if= file\^
input file name; standard input is default
.br
.ns
.TP
.BI of= file\^
output file name; standard output is default
.br
.ns
.TP
.BI ibs= n\^
input block size
.I n\^
bytes (default 512)
.br
.ns
.TP
.BI obs= n\^
output block size (default 512)
.br
.ns
.TP
.BI bs= n\^
set both input and output block size,
superseding
.I ibs\^
and
.IR obs ;
also, if no conversion is specified,
it is particularly efficient since no in-core copy need be done
.br
.ns
.TP
.BI cbs= n\^
conversion buffer size
.br
.ns
.TP
.BI skip= n\^
skip
.IR n ""
input records before starting copy
.br
.ns
.TP
.BI seek= n\^
seek
.I n\^
records from beginning of output file before copying
.br
.ns
.TP
.BI count= n\^
copy only
.IR n ""
input records
.br
.ns
.TP
.B conv=ascii
convert \s-1EBCDIC\s0 to \s-1ASCII\s0
.br
.ns
.RS "\w'\fBconv=\fP'u"
.TP "\w'\fB.\|.\|.\ ,\ .\|.\|.\ \ \fP'u"
.B ebcdic
convert \s-1ASCII\s0 to \s-1EBCDIC\s0
.br
.ns
.TP
.B ibm
slightly different map of \s-1ASCII\s0 to \s-1EBCDIC\s0
.br
.ns
.TP
.B lcase
map alphabetics to lower case
.br
.ns
.TP
.B ucase
map alphabetics to upper case
.br
.ns
.TP
.B swab
swap every pair of bytes
.br
.ns
.TP
.B noerror
do not stop processing on an error
.br
.ns
.TP
.B sync
pad every input record to
.I  ibs\^
.br
.ns
.TP
.B ".\|.\|. , .\|.\|."
several comma-separated conversions
.RE
.PP
.fi
Where sizes are specified,
a number of bytes is expected.
A number may end with
.BR k ,
.BR b ,
or
.B w
to specify multiplication by
1024, 512, or 2 respectively;
a pair of numbers may be separated by
.B x
to indicate a product.
.PP
.I Cbs\^
is used only if
.I ascii\^
or
.I ebcdic\^
conversion is specified.
In the former case
.I cbs\^
characters are placed into the conversion buffer, converted to
\s-1ASCII\s0, and trailing blanks trimmed and new-line added
before sending the line to the output.
In the latter case \s-1ASCII\s0 characters are read into the
conversion buffer, converted to \s-1EBCDIC\s0, and blanks added
to make up an
output record of size
.IR cbs .
.PP
After completion,
.I dd\^
reports the number of whole and partial input and output
blocks.
.SH EXAMPLE
This command will read an \s-1EBCDIC\s0 tape blocked ten 80-byte
\s-1EBCDIC\s0 card images per record into the \s-1ASCII\s0 file
.BR x\| :
.PP
.RS
.nf
dd  if=/dev/rmt0  of=x  ibs=800  cbs=80  conv=ascii,lcase
.fi
.RE
.PP
Note the use of raw magtape.
.I Dd\^
is especially suited to I/O on the raw
physical devices because it allows reading
and writing in arbitrary record sizes.
.SH "SEE ALSO"
cp(1).
.if t .bp
.SH DIAGNOSTICS
.IR "f+p records in(out)" "	numbers of full and partial records read(written)"
.SH BUGS
The \s-1ASCII\s0/\s-1EBCDIC\s0 conversion tables are
taken
from the 256 character standard in
the \s-1CACM\s0 Nov, 1968.
The
.I ibm\^
conversion, while less blessed as a standard,
corresponds better to certain \s-1IBM\s0
print train conventions.
There is no universal solution.
.PP
New-lines are inserted only on conversion to \s-1ASCII\s0;
padding is done only on conversion to \s-1EBCDIC\s0.
These should be separate options.