dd - convert and copy a file
Copy a file, converting and formatting according to the options.
- force ibs=BYTES and obs=BYTES
- convert BYTES bytes at a time
- convert the file as per the comma separated keyword list
- copy only BLOCKS input blocks
- read BYTES bytes at a time
- read from FILE instead of stdin
- write BYTES bytes at a time
- write to FILE instead of stdout
- skip BLOCKS obs-sized blocks at start of output
- skip BLOCKS ibs-sized blocks at start of input
- display this help and exit
- 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
Written by Paul Rubin, David MacKenzie, and Stuart Kemp.
Report bugs to <firstname.lastname@example.org>.
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.
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.
- 2005-06-25 Created from Linux manpage (Ubuntu hoary)