92 lines
1.9 KiB
Groff
92 lines
1.9 KiB
Groff
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.Dd 2020-04-28
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.Dt DD 1
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.Os sbase
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.Sh NAME
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.Nm dd
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.Nd convert and copy a file
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.Sh SYNOPSIS
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.Nm
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.Op Ar operand Ns ...
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.Sh DESCRIPTION
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.Nm
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copies its input to its output, possibly after conversion, using
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the specified block sizes,
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.Pp
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The following operands are available:
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.Bl -tag -width ibs=expr
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.It Cm if= Ns Ar file
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Read from the file named by
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.Ar file
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instead of standard input.
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.It Cm of= Ns Ar file
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Write to the file named by
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.Ar file
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instead of standard output.
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.It Cm ibs= Ns Ar expr
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Set the input block size to
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.Ar expr
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(defaults to 512).
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.It Cm obs= Ns Ar expr
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Set the output block size to
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.Ar expr
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(defaults to 512).
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.It Cm bs= Ns Ar expr
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Set the input and output block sizes to
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.Ar expr .
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Additionally, if no conversion other than
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.Cm noerror ,
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.Cm notrunc ,
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or
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.Cm sync
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is specified, input blocks are copied as single output blocks, even
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when the input block is short.
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.It Cm skip= Ns Ar n
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Skip
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.Ar n
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input blocks before starting to copy.
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.It Cm seek= Ns Ar n
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Skip
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.Ar n
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output blocks before starting to copy.
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.It Cm count= Ns Ar n
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Copy at most
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.Ar n
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input blocks.
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.It Cm conv= Ns Ar value Ns Op , Ns Ar value Ns ...
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Apply the conversions specified by
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.Ar value .
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.Bl -tag -width Ds
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.It Cm lcase
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Map uppercase characters to the corresponding lowercase character
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using
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.Fn tolower .
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.It Cm ucase
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Map lowercase characters to the corresponding uppercase character
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using
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.Fn toupper .
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.It Cm swab
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Swap each pair of bytes in the input block.
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If there is an odd number of bytes in a block, the last one is
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unmodified.
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.It Cm noerror
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In case of an error reading from the input, do not fail.
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Instead, print a diagnostic message and a summary of the current
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status.
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.It Cm notrunc
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Do not truncate the output file.
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.It Cm sync
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In case of a partial input block, pad with null bytes to form a
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complete block.
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.El
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.El
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.Sh STANDARDS
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The
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.Nm
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utility is compliant with the
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.St -p1003.1-2008
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specification, except that it does not implement the
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.Cm block
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and
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.Cm unblock
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conversions.
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