1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
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)
|
