man/cat1/dd.1.txt
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DD(1) User Commands DD(1)
NAME dd - convert and copy a file SYNOPSIS dd [OPERAND]... dd OPTION DESCRIPTION Copy a file, converting and formatting according to the operands. bs=BYTES force ibs=BYTES and obs=BYTES cbs=BYTES convert BYTES bytes at a time conv=CONVS convert the file as per the comma separated sym- bol list count=BLOCKS copy only BLOCKS input blocks ibs=BYTES read BYTES bytes at a time 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 of=FILE write to FILE instead of stdout oflag=FLAGS write as per the comma separated symbol list seek=BLOCKS skip BLOCKS obs-sized blocks at start of output skip=BLOCKS skip BLOCKS ibs-sized blocks at start of input status=noxfer suppress transfer statistics BLOCKS and BYTES may be followed by the following multi- plicative 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 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 nocreat do not create the output file excl fail if the output file already exists 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 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) direct use direct I/O for data dsync use synchronized I/O for data sync likewise, but also for metadata nonblock use non-blocking I/O nofollow do not follow symlinks noctty do not assign controlling terminal from file Sending a SIGUSR1 signal to a running `dd' process makes it print I/O statistics to standard error, then to resume copying. $ dd if=/dev/zero of=/dev/null& pid=$! $ kill -USR1 $pid; sleep 1; kill $pid 18335302+0 records in 18335302+0 records out 9387674624 bytes (9.4 GB) copied, 34.6279 sec- onds, 271 MB/s 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 Report bugs to <bug-coreutils@gnu.org>. COPYRIGHT Copyright (C) 2004 Free Software Foundation, Inc. This is free software; see the source for copying condi- tions. There is NO warranty; not even for MERCHANTABIL- ITY 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 dd should give you access to the complete manual. dd (coreutils) 5.3.0 November 2004 DD(1) |