Set both input and output block sizes to @var{bytes}.
This makes @command{dd} read and write @var{bytes} per block,
overriding any @samp{ibs} and @samp{obs} settings.
-In addition, if no data-transforming @option{conv} option is specified,
+In addition, if no data-transforming @option{conv} operand is specified,
input is copied to the output as soon as it's read,
even if it is smaller than the block size.
@item status=@var{level}
@opindex status
-Transfer information is normally output to stderr upon
-receipt of the @samp{INFO} signal or when @command{dd} exits.
-Specifying @var{level} will adjust the amount of information printed,
-with the last @var{level} specified taking precedence.
+Specify the amount of information printed.
+If this operand is given multiple times, the last one takes precedence.
+The @var{level} value can be one of the following:
@table @samp
@end table
+Transfer information is normally output to stderr upon
+receipt of the @samp{INFO} signal or when @command{dd} exits,
+and defaults to the following form in the C locale:
+
+@example
+7287+1 records in
+116608+0 records out
+59703296 bytes (60 MB, 57 MiB) copied, 0.0427974 s, 1.4 GB/s
+@end example
+
+The notation @samp{@var{w}+@var{p}} stands for @var{w} whole blocks
+and @var{p} partial blocks. A partial block occurs when a read or
+write operation succeeds but transfers less data than the block size.
+An additional line like @samp{1 truncated record} or @samp{10
+truncated records} is output after the @samp{records out} line if
+@samp{conv=block} processing truncated one or more input records.
+
@item conv=@var{conversion}[,@var{conversion}]@dots{}
@opindex conv
Convert the file as specified by the @var{conversion} argument(s).
Convert EBCDIC to ASCII,
using the conversion table specified by POSIX@.
This provides a 1:1 translation for all 256 bytes.
-This option implies @samp{conv=unblock}; input is converted to
+This implies @samp{conv=unblock}; input is converted to
ASCII before trailing spaces are deleted.
@item ebcdic
@opindex ebcdic@r{, converting to}
Convert ASCII to EBCDIC@.
This is the inverse of the @samp{ascii} conversion.
-This option implies @samp{conv=block}; trailing spaces are added
+This implies @samp{conv=block}; trailing spaces are added
before being converted to EBCDIC@.
@item ibm
for @samp{~}, @samp{[}, and @samp{]}.
The @samp{ascii}, @samp{ebcdic}, and @samp{ibm} conversions are
-mutually exclusive. If you use any of these options, you should also
-use the @samp{cbs=} option.
+mutually exclusive. If you use any of these conversions, you should also
+use the @samp{cbs=} operand.
@item block
@opindex block @r{(space-padding)}
For each line in the input, output @samp{cbs} bytes, replacing the
-input newline with a space and padding with spaces as necessary.
+input newline with a space and truncating or padding input lines with
+spaces as necessary.
@item unblock
@opindex unblock
Try to seek rather than write NUL output blocks.
On a file system that supports sparse files, this will create
sparse output when extending the output file.
-Be careful when using this option in conjunction with
+Be careful when using this conversion in conjunction with
@samp{conv=notrunc} or @samp{oflag=append}.
With @samp{conv=notrunc}, existing data in the output file
corresponding to NUL blocks from the input, will be untouched.
With @samp{oflag=append} the seeks performed will be ineffective.
Similarly, when the output is a device rather than a file,
-NUL input blocks are not copied, and therefore this option
+NUL input blocks are not copied, and therefore this conversion
is most useful with virtual or pre zeroed devices.
@item swab
and reflected in the exit status.
Note data that is not already persisted to storage will not
-be discarded from cache, so note the use of the ``sync'' options
+be discarded from cache, so note the use of the @samp{sync} conversions
in the examples below, which are used to maximize the
effectiveness of the @samp{nocache} flag.
@cindex controlling terminal
Do not assign the file to be a controlling terminal for @command{dd}.
This has no effect when the file is not a terminal.
-On many hosts (e.g., GNU/Linux hosts), this option has no effect
+On many hosts (e.g., GNU/Linux hosts), this flag has no effect
at all.
@item nofollow
@item binary
@opindex binary
@cindex binary I/O
-Use binary I/O@. This option has an effect only on nonstandard
+Use binary I/O@. This flag has an effect only on nonstandard
platforms that distinguish binary from text I/O.
@item text
@opindex text
@cindex text I/O
-Use text I/O@. Like @samp{binary}, this option has no effect on
+Use text I/O@. Like @samp{binary}, this flag has no effect on
standard platforms.
@item fullblock
However, in some cases such a tool is not available or the administrator
feels more comfortable with the handling of @command{dd}.
As a simple rescue method, call @command{dd} as shown in the following
-example: the options @samp{conv=noerror,sync} are used to continue
+example: the operand @samp{conv=noerror,sync} is used to continue
after read errors and to pad out bad reads with NULs, while
@samp{iflag=fullblock} caters for short reads (which traditionally never
occur on disk based devices):
5000000000 bytes (5.0 GB, 4.7 GiB) copied, 1.44433 s, 3.5 GB/s
@end example
-The @samp{status=progress} option periodically updates the last line
+The @samp{status=progress} operand periodically updates the last line
of the transfer statistics above.
@vindex POSIXLY_CORRECT
projects / thirdparty / coreutils.git / commitdiff
