.\" DO NOT MODIFY THIS FILE! It was generated by help2man 1.35. .TH DD "1" "March 2007" "GNU coreutils 6.9" "User Commands" .SH NAME dd \- convert and copy a file .SH SYNOPSIS .B dd [\fIOPERAND\fR]... .br .B dd \fIOPTION\fR .SH DESCRIPTION .\" Add any additional description here .PP Copy a file, converting and formatting according to the operands. .TP bs=BYTES force ibs=BYTES and obs=BYTES .TP cbs=BYTES convert BYTES bytes at a time .TP conv=CONVS convert the file as per the comma separated symbol list .TP count=BLOCKS copy only BLOCKS input blocks .TP ibs=BYTES read BYTES bytes at a time .TP if=FILE read from FILE instead of stdin .TP iflag=FLAGS read as per the comma separated symbol list .TP obs=BYTES write BYTES bytes at a time .TP of=FILE write to FILE instead of stdout .TP oflag=FLAGS write as per the comma separated symbol list .TP seek=BLOCKS skip BLOCKS obs\-sized blocks at start of output .TP skip=BLOCKS skip BLOCKS ibs\-sized blocks at start of input .TP status=noxfer suppress transfer statistics .PP 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. .PP Each CONV symbol may be: .TP ascii from EBCDIC to ASCII .TP ebcdic from ASCII to EBCDIC .TP ibm from ASCII to alternate EBCDIC .TP block pad newline\-terminated records with spaces to cbs\-size .TP unblock replace trailing spaces in cbs\-size records with newline .TP lcase change upper case to lower case .TP nocreat do not create the output file .TP excl fail if the output file already exists .TP notrunc do not truncate the output file .TP ucase change lower case to upper case .TP swab swap every pair of input bytes .TP noerror continue after read errors .TP sync pad every input block with NULs to ibs\-size; when used with block or unblock, pad with spaces rather than NULs .TP fdatasync physically write output file data before finishing .TP fsync likewise, but also write metadata .PP Each FLAG symbol may be: .TP append append mode (makes sense only for output; conv=notrunc suggested) .TP direct use direct I/O for data .IP directory fail unless a directory dsync use synchronized I/O for data sync likewise, but also for metadata nonblock use non\-blocking I/O noatime do not update access time noctty do not assign controlling terminal from file nofollow do not follow symlinks .PP Sending a USR1 signal to a running `dd' process makes it print I/O statistics to standard error and then resume copying. .IP \f(CW$ dd if=/dev/zero of=/dev/null& pid=$!\fR .br \f(CW$ kill -USR1 $pid; sleep 1; kill $pid\fR .IP 18335302+0 records in 18335302+0 records out 9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s .PP Options are: .TP \fB\-\-help\fR display this help and exit .TP \fB\-\-version\fR output version information and exit .SH AUTHOR Written by Paul Rubin, David MacKenzie, and Stuart Kemp. .SH "REPORTING BUGS" Report bugs to . .SH COPYRIGHT Copyright \(co 2007 Free Software Foundation, Inc. .br This is free software. You may redistribute copies of it under the terms of the GNU General Public License . There is NO WARRANTY, to the extent permitted by law. .SH "SEE ALSO" The full documentation for .B dd is maintained as a Texinfo manual. If the .B info and .B dd programs are properly installed at your site, the command .IP .B info dd .PP should give you access to the complete manual.