dd(1)

dd - convert and copy a file

dd [\,OPERAND\/]...
dd \,OPTION\/

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	skip N obs-sized blocks at start of output
skip=N	skip N ibs-sized blocks at start of input
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. Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
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
directory
	fail unless a directory
dsync	use synchronized I/O for data
sync	likewise, but also for metadata
fullblock
	accumulate full blocks of input (iflag only)
nonblock
	use non-blocking I/O
noatime
	do not update access time
nocache
	Request to drop cache. See also oflag=sync
noctty	do not assign controlling terminal from file
nofollow
	do not follow symlinks
count_bytes
	treat ’count=N’ as a byte count (iflag only)
skip_bytes
	treat ’skip=N’ as a byte count (iflag only)
seek_bytes
	treat ’seek=N’ as a byte count (oflag only)
Sending a USR1 signal to a running ’dd’ process makes it print I/O statistics to standard error and then resume copying.
Options are:
--help	display this help and exit
--version
	output version information and exit

Written by Paul Rubin, David MacKenzie, and Stuart Kemp.

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>

Copyright © 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

Full documentation <https://www.gnu.org/software/coreutils/dd>
or available locally via: info \(aq(coreutils) dd invocation\(aq

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