dd(1) | dd(1) |
swab | Swap every pair of input bytes. |
noerror | Do not stop processing on an input error. If the sync conversion |
| symbol is also speci®ed, missing input is replaced with null bytes |
| and processed normally; otherwise, the input block is omitted from |
| the output. |
notrunc | Do not truncate existing output ®le. Blocks in the output ®le not |
| overwritten by this invocation of dd are preserved. |
sync | Pad every input block to size ibs. If block or unblock is also |
| speci®ed, pad with space characters; otherwise, pad with null |
| bytes. |
Where sizes are required, n indicates a numerical value in bytes. Numbers can be speci®ed using the forms:
nfor n bytes
nk for n Kbytes (n × 1024),
nb for n blocks (n × 512), or
nw for n words (n × 2).
To indicate a product, use x to separate number pairs.
The cbs option is used when block, unblock, ascii or ebcdic conversion is speci®ed. In case of ascii, cbs characters are placed into the conversion buffer, converted to ASCII, trailing blanks are trimmed, and a newline is added before sending the line to the output. In case of ebcdic, ASCII characters are read into the conversion buffer, converted to EBCDIC, and blanks are added to make up an output block of size cbs.
EXTERNAL INFLUENCES
International Code Set Support
Single- and
Environment Variables
The following environment variables affect execution of dd:
LANG determines the locale when LC_ALL and a corresponding variable (beginning with LC_) do not specify a locale.
LC_ALL determines the locale used to override any values set by LANG or any environment variables beginning with LC_.
The LC_CTYPE variable determines the locale for the interpretation of sequences of bytes of text data as characters
The LC_MESSAGES variable determines the language in which messages are written.
RETURN VALUE
Exit values are:
0Successful completion. >0 Error condition occurred.
DIAGNOSTICS
Upon completion, dd reports the number of input and output records:
f+p | records | in | Number of full and partial blocks read. |
f+p | records | out | Number of full and partial blocks written. |
When conv=block is speci®ed and there is at least one truncated block, the number of truncated records is also reported:
n truncated records
EXAMPLES
Read an EBCDIC tape blocked ten
dd if=/dev/rmt/c0t0d0BEST of=x ibs=800 cbs=80 conv=ascii,lcase
d
− 2 − | Section 1−173 |