dd - convert and copy a file

NAME SYNOPSIS DESCRIPTION AUTHOR REPORTING BUGS COPYRIGHT SEE ALSO

DESCRIPTION

Copy a file, converting and formatting according to the operands.
bs=BYTES

read and write up to BYTES bytes at a time (default: 512); overrides ibs and obs

cbs=BYTES

convert BYTES bytes at a time

conv=CONVS

convert the file as per the comma separated symbol list

count=N

copy only N input blocks

ibs=BYTES

read up to BYTES bytes at a time (default: 512)

if=FILE

read from FILE instead of stdin

iflag=FLAGS

read as per the comma separated symbol list

obs=BYTES

write BYTES bytes at a time (default: 512)

of=FILE

write to FILE instead of stdout

oflag=FLAGS

write as per the comma separated symbol list

	seek=N		(or oseek=N) skip N obs−sized output blocks
	skip=N		(or iseek=N) skip N ibs−sized input blocks

status=LEVEL

The LEVEL of information to print to stderr; ’none’ suppresses everything but error messages, ’noxfer’ suppresses the final transfer statistics, ’progress’ shows periodic transfer statistics

N and BYTES may be followed by the following multiplicative suffixes: c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, xM=M, GB=1000*1000*1000, G=1024*1024*1024, and so on for T, P, E, Z, Y, R, Q. Binary prefixes can be used, too: KiB=K, MiB=M, and so on. If N ends in ’B’, it counts bytes not blocks.

Each CONV symbol may be:

	ascii		from EBCDIC to ASCII
	ebcdic		from ASCII to EBCDIC
	ibm		from ASCII to alternate EBCDIC
	block		pad newline−terminated records with spaces to cbs−size

unblock

replace trailing spaces in cbs−size records with newline

	lcase		change upper case to lower case
	ucase		change lower case to upper case
	sparse		try to seek rather than write all−NUL output blocks
	swab		swap every pair of input bytes
	sync		pad every input block with NULs to ibs−size; when used with block or unblock, pad with spaces rather than NULs
	excl		fail if the output file already exists

nocreat

do not create the output file

notrunc

do not truncate the output file

noerror

continue after read errors

fdatasync

physically write output file data before finishing

fsync

likewise, but also write metadata

Each FLAG symbol may be:

	append		append mode (makes sense only for output; conv=notrunc suggested)
	direct		use direct I/O for data

	dsync		use synchronized I/O for data
	sync		likewise, but also for metadata