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