Linux in a Nutshell, Fourth Edition

Name

dd

Synopsis

                  dd 
                  options
               

Make a copy of an input file (if) using the specified conditions, and send the results to the output file (or standard output if of is not specified). Any number of options can be supplied, although if and of are the most common and are usually specified first. Because dd can handle arbitrary blocksizes, it is useful when converting between raw physical devices.

Options

bs= n

Set input and output blocksize to n bytes; this option overrides ibs and obs.

cbs= n

Set the size of the conversion buffer (logical record length) to n bytes. Use only if the conversion flag is ascii, ebcdic, ibm, block, or unblock.

conv= flags

Convert the input according to one or more (comma-separated) flags listed next. The first five flags are mutually exclusive.

ascii

EBCDIC to ASCII.

ebcdic

ASCII to EBCDIC.

ibm

ASCII to EBCDIC with IBM conventions.

block

Variable-length records (i.e., those terminated by a newline) to fixed-length records.

unblock

Fixed-length records to variable-length records.

lcase

Uppercase to lowercase.

ucase

Lowercase to uppercase.

noerror

Continue processing after read errors.

notrunc

Don’t truncate output file.

swab

Swap each pair of input bytes.

sync

Pad input blocks to ibs with trailing zeros.

count= n

Copy only n input blocks.

ibs= n

Set input blocksize to n bytes (default is 512).

if= file

Read input from file (default is standard input).

obs= n

Set output blocksize to n bytes (default is 512).

of= file

Write output to file (default is standard output). ...