dd

DD(1) User Commands DD(1)

NAME

dd - convert and copy a file


SYNOPSIS
dd [OPTION]...

DESCRIPTION

Copy a file, converting and formatting according to the options.


bs=BYTES
force ibs=BYTES and obs=BYTES


cbs=BYTES
convert BYTES bytes at a time


conv=KEYWORDS
convert the file as per the comma separated keyword list


count=BLOCKS
copy only BLOCKS input blocks


ibs=BYTES
read BYTES bytes at a time


if=FILE
read from FILE instead of stdin


obs=BYTES
write BYTES bytes at a time


of=FILE
write to FILE instead of stdout


seek=BLOCKS
skip BLOCKS obs-sized blocks at start of output


skip=BLOCKS
skip BLOCKS ibs-sized blocks at start of input


--help display this help and exit


--version
output version information and exit


BLOCKS and BYTES may be followed by the following multiplicative suf-
fixes: xM M, c 1, w 2, b 512, kB 1000, K 1024, MB 1000*1000, M
1024*1024, GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E,
Z, Y. Each KEYWORD may be:


ascii from EBCDIC to ASCII


ebcdic from ASCII to EBCDIC


ibm from ASCII to alternated 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


notrunc
do not truncate the output file


ucase change lower case to upper case


swab swap every pair of input bytes


noerror
continue after read errors


sync pad every input block with NULs to ibs-size; when used


with block or unblock, pad with spaces rather than NULs


Note that sending a SIGUSR1 signal to a running "dd" process makes it
print to standard error the number of records read and written so far,
then to resume copying.


$ dd if=/dev/zero of=/dev/null& pid=$!
$ kill -USR1 $pid; sleep 1; kill $pid


10899206+0 records in 10899206+0 records out

AUTHOR

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


REPORTING BUGS
Report bugs to .

COPYRIGHT

Copyright © 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is
NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.



SEE ALSO

The full documentation for dd is maintained as a Texinfo manual. If
the info and dd programs are properly installed at your site, the com-
mand


info coreutils dd


should give you access to the complete manual.






dd (coreutils) 5.2.1 July 2004 DD(1)