|IBM to unix
| Treats the input as a sequence of fixed length records
independent of input and output block boundaries as specified by |
Trailing spaces are discarded and a new-line character is appended.
| in additional to |
characters are translated from EBCDIC to ASCII. Implies
cbs is also specified.
| unix to IBM
|Treats the input as a sequence of newline or end-of-file terminated variable
length records independent of input and output block boundaries.|
Trailing newline characters are discarded.
Input records are converted to a fixed length output records as specified by
by padding with spaces or truncated!
The number of truncated records, is reported to the standard error output at the completion of the copy.
| in additional to |
block characters are also are translated from
ASCII† to EBCDIC
cbs=b is also specified.)
ebcdic , (
ibm is slightly different
|Transform uppercase characters into lowercase
| Transform lowercase characters into uppercase characters.
yes it's a B
| Swap every pair of input bytes.
|Pad input block to the input buffer size with |
block oriented conversion,
NUL bytes are used.
| Pad the final output block to the output block size. |
If the input file is not a multiple of the output block size after conversion,
forces the final output block to be the same size as preceding blocks for
use on devices that require regularly sized blocks to be written.
Incompatible with use of the
|Do not stop processing on an input error. rather a
diagnostic message followed by the current input and output block counts
will be written to the standard error output .|
sync is also specified, missing input data will be replaced with
spaces if a block oriented conversion was specified) and processed as a normal
sync is not specified, the input block is omitted from the output.
On input files which are not tapes or pipes, the file offset will be positioned past the block in which the error occurred using lseek(2).
|Do not truncate the output file
rather preserve any blocks in the output file not explicitly written by dd, |
not supported for tapes.
|If one or more output blocks would consist solely of NUL bytes, |
try to seek the output file by the required space instead of filling them with
resulting in a sparse file.
Sizes are specified in decimal, octal, or hexadecimal bytes .
w, the number is multiplied by 512,
1,024 (1K), 1,048,576 (1M), 1,073,741,824 (1G) or the number of bytes in an integer, respectively.
Two or more numbers may be separated by an
x to indicate a product.
When finished displays the number of complete and partial input and output blocks, truncated input records and odd-length byte-swapping blocks to the standard error output. A partial input block is one where less than the input block size was read. A partial output block
is one where less than the output block size was written.
Partial output blocks to tape devices are fatal errors. Otherwise, the rest of the block will be written.
Partial output blocks to character devices will produce a warning message. A truncated input block is one where a variable length record oriented conversion value was specified and the
input line was too long to fit in the conversion record or was not newline terminated.
Normally, data resulting from input or conversion or both are aggregated into output blocks of
the specified size. After the end of input is reached, any remaining output is written as a
block. This means that the final output block may be shorter than the output block size.
If dd receives a
SIGINFO ( aka
^t see the status argument for stty signal, the current input and
output block counts will be written to the standard error output in the same format as the
standard completion message.
If dd receives a
SIGINT signal it behaves as if the end of the input had been reached.
exits 0 on success, and >0 if an error occurs.
load: 0.19 cmd: dd 89246 running 0.32u 1.99s
329272+0 records in
329272+0 records out
168587264 bytes transferred in 6.675876 secs (25253204 bytes/sec)
from 32GB raspberry pi SD bs=1M
30436+1 records in
30436+1 records out
31,914,983,424 bytes transferred in 7,125.643065 secs (4,478,892 bytes/sec) Nearly 2 hours !!