1 .\" DO NOT MODIFY THIS FILE! It was generated by help2man 1.43.3.
2 .TH DD "1" "May 2014" "GNU coreutils 8.22" "User Commands"
4 dd \- convert and copy a file
12 .\" Add any additional description here
14 Copy a file, converting and formatting according to the operands.
17 read and write up to BYTES bytes at a time
20 convert BYTES bytes at a time
23 convert the file as per the comma separated symbol list
26 copy only N input blocks
29 read up to BYTES bytes at a time (default: 512)
32 read from FILE instead of stdin
35 read as per the comma separated symbol list
38 write BYTES bytes at a time (default: 512)
41 write to FILE instead of stdout
44 write as per the comma separated symbol list
47 skip N obs\-sized blocks at start of output
50 skip N ibs\-sized blocks at start of input
53 WHICH info to suppress outputting to stderr;
54 \&'noxfer' suppresses transfer stats, 'none' suppresses all
56 N and BYTES may be followed by the following multiplicative suffixes:
57 c =1, w =2, b =512, kB =1000, K =1024, MB =1000*1000, M =1024*1024, xM =M
58 GB =1000*1000*1000, G =1024*1024*1024, and so on for T, P, E, Z, Y.
60 Each CONV symbol may be:
69 from ASCII to alternate EBCDIC
72 pad newline\-terminated records with spaces to cbs\-size
75 replace trailing spaces in cbs\-size records with newline
78 change upper case to lower case
81 change lower case to upper case
84 try to seek rather than write the output for NUL input blocks
87 swap every pair of input bytes
90 pad every input block with NULs to ibs\-size; when used
91 with block or unblock, pad with spaces rather than NULs
94 fail if the output file already exists
97 do not create the output file
100 do not truncate the output file
103 continue after read errors
106 physically write output file data before finishing
109 likewise, but also write metadata
111 Each FLAG symbol may be:
114 append mode (makes sense only for output; conv=notrunc suggested)
117 use direct I/O for data
120 fail unless a directory
123 use synchronized I/O for data
126 likewise, but also for metadata
129 accumulate full blocks of input (iflag only)
132 use non\-blocking I/O
135 do not update access time
141 do not assign controlling terminal from file
144 do not follow symlinks
147 treat 'count=N' as a byte count (iflag only)
150 treat 'skip=N' as a byte count (iflag only)
153 treat 'seek=N' as a byte count (oflag only)
155 Sending a USR1 signal to a running 'dd' process makes it
156 print I/O statistics to standard error and then resume copying.
158 \f(CW$ dd if=/dev/zero of=/dev/null& pid=$!\fR
160 \f(CW$ kill -USR1 $pid; sleep 1; kill $pid\fR
162 18335302+0 records in
163 18335302+0 records out
164 9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s
169 display this help and exit
172 output version information and exit
174 GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
175 Report dd translation bugs to <http://translationproject.org/team/>
177 Written by Paul Rubin, David MacKenzie, and Stuart Kemp.
179 Copyright \(co 2013 Free Software Foundation, Inc.
180 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
182 This is free software: you are free to change and redistribute it.
183 There is NO WARRANTY, to the extent permitted by law.
185 The full documentation for
187 is maintained as a Texinfo manual. If the
191 programs are properly installed at your site, the command
193 .B info coreutils \(aqdd invocation\(aq
195 should give you access to the complete manual.