Manual: rust-dd

DD(1)						   General Commands Manual					       DD(1)

NAME
       dd - Copy, and optionally convert, a file system resource

SYNOPSIS
       dd [-h|--help] [-V|--version] [operands]

DESCRIPTION
       Copy, and optionally convert, a file system resource

OPTIONS
       -h, --help
	      Print help

       -V, --version
	      Print version

       [operands]

EXTRA
       ### Operands

       - bs=BYTES : read and write up to BYTES bytes at a time (default: 512);
	  overwrites ibs and obs.  - cbs=BYTES : the 'conversion block size' in bytes. Applies to the
	  conv=block,  and  conv=unblock  operations.	-  conv=CONVS : a comma-separated list of conversion options or (for
       legacy
	  reasons) file flags.	- count=N : stop reading input after N ibs-sized read operations rather
	  than proceeding until EOF. See iflag=count_bytes if stopping after N bytes
	  is preferred - ibs=N : the size of buffer used for reads (default: 512) - if=FILE : the file used for input.	When
       not specified, stdin is used instead - iflag=FLAGS : a comma-separated list of input flags which specify how the
	  input source is treated. FLAGS may be any of the input-flags or general-flags
	  specified below.  - skip=N (or iseek=N) : skip N ibs-sized records into input before beginning
	  copy/convert	operations. See iflag=seek_bytes if seeking N bytes is preferred.  - obs=N : the size of buffer used
       for writes (default: 512) - of=FILE : the file used for output. When not specified, stdout is used
	  instead - oflag=FLAGS : comma separated list of output flags which specify how the
	  output source is treated. FLAGS may be any of the output flags or general
	  flags specified below - seek=N (or oseek=N) : seeks N obs-sized records into output before
	  beginning copy/convert operations. See oflag=seek_bytes if seeking N bytes is
	  preferred - status=LEVEL : controls whether volume and performance stats are written to
	  stderr.

	 When unspecified, dd will print stats upon completion. An example is below.

	 ```plain
	   6+0 records in
	   16+0 records out
	   8192 bytes (8.2 kB, 8.0 KiB) copied, 0.00057009 s,
	   14.4 MB/s

	 The first two lines are the 'volume' stats and the final line is the
	 'performance' stats.
	 The volume stats indicate the number of complete and partial ibs-sized reads,
	 or obs-sized writes that took place during the copy. The format of the volume
	 stats is +. If records have been truncated (see
	 conv=block), the volume stats will contain the number of truncated records.

	 Possible LEVEL values are:
	 - progress : Print periodic performance stats as the copy proceeds.
	 - noxfer : Print final volume stats, but not performance stats.
	 - none : Do not print any stats.

	 Printing performance stats is also triggered by the INFO signal (where supported),
	 or the USR1 signal. Setting the POSIXLY_CORRECT environment variable to any value
	 (including an empty value) will cause the USR1 signal to be ignored.

       ### Conversion Options

       - ascii : convert from EBCDIC to ASCII. This is the inverse of the ebcdic
	 option. Implies conv=unblock.	- ebcdic : convert from ASCII to EBCDIC. This is the inverse of the ascii
	 option. Implies conv=block.  - ibm : convert from ASCII to EBCDIC, applying the conventions for [, ]
	 and ~ specified in POSIX. Implies conv=block.

       - ucase : convert from lower-case to upper-case.	 - lcase : converts from upper-case to lower-case.

       - block : for each newline less than the size indicated by cbs=BYTES, remove
	 the newline and pad with spaces up to cbs. Lines longer than cbs are truncated.  - unblock : for each block of	 in‐
       put of the size indicated by cbs=BYTES, remove
	 right-trailing spaces and replace with a newline character.

       - sparse : attempts to seek the output when an obs-sized block consists of
	 only zeros.  - swab : swaps each adjacent pair of bytes. If an odd number of bytes is
	 present, the final byte is omitted.  - sync : pad each ibs-sided block with zeros. If block or unblock is
	 specified, pad with spaces instead.  - excl : the output file must be created. Fail if the output file is already
	 present.  - nocreat : the output file will not be created. Fail if the output file in
	 not already present.  - notrunc : the output file will not be truncated. If this option is not
	 present,  output will be truncated when opened.  - noerror : all read errors will be ignored. If this option is not
       present,
	 dd will only ignore Error::Interrupted.  - fdatasync : data will be written before finishing.	- fsync :  data	 and
       metadata will be written before finishing.

       ### Input flags

       -  count_bytes  :  a  value to count=N will be interpreted as bytes.  - skip_bytes : a value to skip=N will be inter‐
       preted as bytes.	 - fullblock : wait for ibs bytes from each read. zero-length reads are still
	 considered EOF.

       ### Output flags

       - append : open file in append mode. Consider setting conv=notrunc as well.  - seek_bytes : a value to seek=N will be
       interpreted as bytes.

       ### General Flags

       - direct : use direct I/O for data.  - directory : fail unless the given input (if used as an iflag) or
	 output (if used as an oflag) is a directory.  - dsync : use synchronized I/O for data.	 - sync :  use	synchronized
       I/O  for	 data and metadata.  - nonblock : use non-blocking I/O.	 - noatime : do not update access time.	 - nocache :
       request that OS drop cache.  - noctty : do not assign a controlling tty.	 - nofollow : do not follow system links.

VERSION
       v(uutils coreutils) 0.8.0

							 2026-04-16						       DD(1)