GNU coreutils 8.32
March 2020
coreutils
The basic file, shell and text manipulation utilities of the GNU operating system
coreutils-common
coreutils common optional components
coreutils-doc
Documentation for the GNU Core Utilities
NAME
dd - convert and copy a file
SYNOPSIS
dd [\,OPERAND\/]...
dd \,OPTION\/
dd \,OPTION\/
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 | 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 |
AUTHOR
Written by Paul Rubin, David MacKenzie, and Stuart Kemp.
REPORTING BUGS
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
Report any translation bugs to <https://translationproject.org/team/>
COPYRIGHT
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.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
Full documentation <https://www.gnu.org/software/coreutils/dd>
or available locally via: info \(aq(coreutils) dd invocation\(aq
or available locally via: info \(aq(coreutils) dd invocation\(aq
REFERENCED BY
devio(1), mkrescue(8), swapon(8), raw(8), xfs(5), xfs_copy(8), xfs_repair(8), fdisk(8), mkswap(8), sfdisk(8), autopsy(1), drivemap(1), bilibop(7), gpart(8), atari-hd-image(1), zip2st(1), ioping(1), cdrecord(1), myrescue(8), nwipe(1), wodim(1), mkbiarch(8), spax(1), scpio(1), STAR(1), dd_rescue(1), dvdrecord(1), myrescue(2), smt(1), ustar(1), fifo(1)