Mac OS X in a Nutshell

Name

dd

Synopsis

dd [option = value]

Makes a copy of an input file (if=), or standard input if no named input file, 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 block sizes, it is useful when converting between raw physical devices.

dd does not preserve resource forks or HFS metadata when copying files that contain them.

Options

bs= n

Set input and output block size to n bytes; this option supersedes 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, asciib, ebcdic, ebcdicb, ibm, ibmb, block, or unblock.

conv= flags

Convert the input according to one or more (comma-separated) flags listed next. The first six flags are mutually exclusive. The next two are mutually exclusive with each other, as are the following two.

ascii

EBCDIC to ASCII.

asciib

EBCDIC to ASCII, using BSD-compatible conversions.

ebcdic

ASCII to EBCDIC.

ebcdicb

ASCII to EBCDIC, using BSD-compatible conversions.

ibm

ASCII to EBCDIC with IBM conventions.

ibmb

ASCII to EBCDIC with IBM conventions, using BSD-compatible conversions.

block

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

unblock

Fixed-length records to variable length.

lcase

Uppercase to lowercase.

ucase

Lowercase to ...