cmd/dd

[[Category:Linux Shell Commands]] Techniques: Linux: dd

Documentation

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 suffixes: 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 <bug-coreutils@gnu.org>. ===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 command info coreutils dd should give you access to the complete manual.

Edit Log

• 2005-06-25 Created from Linux manpage (Ubuntu hoary)