198 lines
3.3 KiB
Text
198 lines
3.3 KiB
Text
.TH DD 1
|
|
.SH NAME
|
|
dd \- convert and copy a file
|
|
.SH SYNOPSIS
|
|
.B dd
|
|
[
|
|
.I 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.
|
|
The options are
|
|
.TP \w'\fLoseek\ \ \fIn'u
|
|
.BI -if\ f
|
|
Open file
|
|
.I f
|
|
for input.
|
|
.TP
|
|
.BI -of\ f
|
|
Open file
|
|
.I f
|
|
for output.
|
|
.TP
|
|
.BI -ibs\ n\^
|
|
Set input block size to
|
|
.I n\^
|
|
bytes (default 512).
|
|
.TP
|
|
.BI -obs\ n\^
|
|
Set output block size (default 512).
|
|
.TP
|
|
.BI -bs\ n\^
|
|
Set both input and output block size,
|
|
superseding
|
|
.I ibs\^
|
|
and
|
|
.IR 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.
|
|
.TP
|
|
.BI -cbs\ n\^
|
|
Set conversion buffer size.
|
|
.TP
|
|
.BI -skip\ n\^
|
|
Skip
|
|
.I n
|
|
input records before copying.
|
|
.TP
|
|
.BI -iseek\ n\^
|
|
Seek
|
|
.I n
|
|
records forward on input file
|
|
before copying.
|
|
.TP
|
|
.BI -files\ n\^
|
|
Catenate
|
|
.I n
|
|
input files (useful only for magnetic tape or similar input device).
|
|
.TP
|
|
.BI -oseek\ n\^
|
|
Seek
|
|
.I n\^
|
|
records from beginning of output file before copying.
|
|
.TP
|
|
.BI -count\ n\^
|
|
Copy only
|
|
.I n
|
|
input records.
|
|
.TP
|
|
.BI -trunc\ n\^
|
|
By default,
|
|
.I dd
|
|
truncates the output file when it opens it;
|
|
.B -trunc
|
|
.B 0
|
|
opens it without truncation.
|
|
.TP
|
|
.BI -quiet\ n\^
|
|
By default,
|
|
.I dd
|
|
prints the number of blocks read and written
|
|
once it is finished.
|
|
.B -quiet
|
|
.B 1
|
|
silences this summary.
|
|
.HP
|
|
\fL-conv\ ascii\ \ \ \ \fRConvert
|
|
.SM EBCDIC
|
|
to
|
|
.SM ASCII.
|
|
.PD0
|
|
.RS "\w'\fLconv\ \fP'u"
|
|
.TP "\w'\fLunblock\ \ \fP'u"
|
|
.B ebcdic
|
|
Convert
|
|
.SM ASCII
|
|
to
|
|
.SM EBCDIC.
|
|
.TP
|
|
.B ibm
|
|
Like
|
|
.B ebcdic
|
|
but with a slightly different character map.
|
|
.TP
|
|
.B block
|
|
Convert variable length
|
|
.SM ASCII
|
|
records to fixed length.
|
|
.TP
|
|
.B unblock
|
|
Convert fixed length
|
|
.SM ASCII
|
|
records to variable length.
|
|
.TP
|
|
.B lcase
|
|
Map alphabetics to lower case.
|
|
.TP
|
|
.B ucase
|
|
Map alphabetics to upper case.
|
|
.TP
|
|
.B swab
|
|
Swap every pair of bytes.
|
|
.TP
|
|
.B noerror
|
|
Do not stop processing on an error.
|
|
.TP
|
|
.B sync
|
|
Pad every input record to
|
|
.I ibs\^
|
|
bytes.
|
|
.RE
|
|
.PD
|
|
.PP
|
|
.fi
|
|
Where sizes are specified,
|
|
a number of bytes is expected.
|
|
A number may end with a sequence
|
|
of
|
|
.LR m ,
|
|
.L k
|
|
or
|
|
.LR b
|
|
to specify multiplications by
|
|
1048576, 1024, or 512 respectively;
|
|
a pair of numbers may be separated by
|
|
.L x
|
|
to indicate a product.
|
|
Multiple conversions may be specified in the style:
|
|
.LR "-conv ebcdic,ucase" .
|
|
.PP
|
|
.L Cbs\^
|
|
is used only if
|
|
.LR ascii\^ ,
|
|
.LR unblock\^ ,
|
|
.LR ebcdic\^ ,
|
|
.LR ibm\^ ,
|
|
or
|
|
.L block\^
|
|
conversion is specified.
|
|
In the first two cases,
|
|
.I n
|
|
characters are copied into the conversion buffer, any specified
|
|
character 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
|
|
.IR n .
|
|
If
|
|
.L cbs\^
|
|
is unspecified or zero, the
|
|
.LR ascii\^ ,
|
|
.LR ebcdic\^ ,
|
|
and
|
|
.L ibm\^
|
|
options convert the character set without changing the block
|
|
structure of the input file; the
|
|
.L unblock\^
|
|
and
|
|
.L block\^
|
|
options become a simple file copy.
|
|
.SH SOURCE
|
|
.B /sys/src/cmd/dd.c
|
|
.SH "SEE ALSO"
|
|
.IR cp (1)
|
|
.SH DIAGNOSTICS
|
|
.I Dd
|
|
reports the number of full + partial input and output
|
|
blocks handled.
|