dd(1l)

NAME

dd - convert a file while copying it

SYNOPSIS

dd [--help] [--version] [if=file] [of=file] [ibs=bytes] [obs=bytes] [bs=bytes] [cbs=bytes] [skip=blocks] [seek=blocks] [count=blocks] [conv={ascii,ebcdic,ibm,block,unblock,lcase,ucase,swab,noerror,notrunc, sync}]

DESCRIPTION

This manual page documents the GNU version of dd . dd copies a file (from the standard input to the standard output, by default) with a user-selectable blocksize, while optionally performing conversions on it.

OPTIONS

Numbers can be followed by a multiplier:
b=512, c=1, k=1024, w=2, xm=number m

--help

Print a usage message on standard output and exit successfully.

--version

Print version information on standard output then exit successfully.

if=file

Read from file instead of the standard input.

of=file

Write to file instead of the standard output. Unless conv=notrunc is given, truncate file to the size specified by seek= (0 bytes if seek= is not given).

ibs=bytes

Read bytes bytes at a time.

obs=bytes

Write bytes bytes at a time.

bs=bytes

Read and write bytes bytes at atime. Override ibs and obs.

cbs=bytes

Convert bytes bytes at a time.

skip=blocks

Skip blocks ibs-sized blocks at start of input.

seek=blocks

Skip blocks obs-sized blocks at start of output.

count=blocks

Copy only blocks ibs-sized input blocks.

conv=conversion[,conversion...]

Convert the file as specified by the conversion arguments.

Conversions:

ascii

Convert EBCDIC to ASCII.

ebcdic

Convert ASCII to EBCDIC.

ibm

Convert ASCII to alternate EBCDIC.

block

Pad newline-terminated records to size of cbs, replacing newline with trailing spaces.

unblock

Replace trailing spaces in cbs-sized block with newline.

lcase

Change uppercase characters to lowercase.

ucase

Change lowercase characters to uppercase.

swab

Swap every pair of input bytes. Unlike the Unix dd, this works when an odd number of bytes are read. If the input file contains an odd number of bytes, the last byte is simply copied (since there is nothing to swap it with).

noerror

Continue after read errors.

notrunc

Do not truncate the output file.

sync

Pad every input block to size of ibs with trailing NULs.