1 .TH DD 1
2 .SH NAME
3 dd \- convert and copy a file
4 .SH SYNOPSIS
5 .B dd
6 [
7 .I option value
8 ]
9 \&...
10 .SH DESCRIPTION
11 .I Dd\^
12 copies the specified input file
13 to the specified output with
14 possible conversions.
15 The standard input and output are used by default.
16 The input and output block size may be
17 specified to take advantage of raw physical I/O.
18 The options are
19 .TF "quiet\ \ \fIn
20 .PD
21 .TP
22 .BI -if\  f
23 Open file
24 .I f
25 for input.
26 .TP
27 .BI -of\  f
28 Open file
29 .I f
30 for output.
31 .TP
32 .BI -ibs\  n\^
33 Set input block size to
34 .I n\^
35 bytes (default 512).
36 .TP
37 .BI -obs\  n\^
38 Set output block size (default 512).
39 .TP
40 .BI -bs\  n\^
41 Set both input and output block size,
42 superseding
43 .I ibs\^
44 and
45 .IR obs .
46 If no conversion is specified,
47 preserve the input block size instead of packing short blocks
48 into the output buffer.
49 This is particularly efficient since no in-core copy need be done.
50 .TP
51 .BI -cbs\  n\^
52 Set conversion buffer size.
53 .TP
54 .BI -skip\  n\^
55 Skip
56 .I n
57 input records before copying.
58 .TP
59 .BI -iseek\  n\^
60 Seek
61 .I n
62 records forward on input file
63 before copying.
64 .TP
65 .BI -files\  n\^
66 Catenate
67 .I n 
68 input files (useful only for magnetic tape or similar input device).
69 .TP
70 .BI -oseek\  n\^
71 Seek
72 .I n\^
73 records from beginning of output file before copying.
74 .TP
75 .BI -count\  n\^
76 Copy only
77 .I n
78 input records.
79 .TP
80 .BI -trunc\  n\^
81 By default,
82 .I dd
83 truncates the output file when it opens it;
84 .B -trunc
85 .B 0
86 opens it without truncation.
87 .TP
88 .BI -quiet\  n\^
89 By default,
90 .I dd
91 prints the number of blocks read and written
92 once it is finished.
93 .B -quiet
94 .B 1
95 silences this summary.
96 .HP
97 \fL-conv\ ascii\ \ \ \ \fRConvert
98 .SM EBCDIC
99 to
100 .SM ASCII.
101 .PD0
102 .RS "\w'\fLconv\ \fP'u"
103 .TP "\w'\fLunblock\ \ \fP'u"
104 .B ebcdic
105 Convert
106 .SM ASCII
107 to
108 .SM EBCDIC.
109 .TP
110 .B ibm
111 Like
112 .B ebcdic
113 but with a slightly different character map.
114 .TP
115 .B block
116 Convert variable length
117 .SM ASCII
118 records to fixed length.
119 .TP
120 .B unblock
121 Convert fixed length
122 .SM ASCII
123 records to variable length.
124 .TP
125 .B lcase
126 Map alphabetics to lower case.
127 .TP
128 .B ucase
129 Map alphabetics to upper case.
130 .TP
131 .B swab
132 Swap every pair of bytes.
133 .TP
134 .B noerror
135 Do not stop processing on an error.
136 .TP
137 .B sync
138 Pad every input record to
139 .I  ibs\^
140 bytes.
141 .RE
142 .PD
143 .PP
144 .fi
145 Where sizes are specified,
146 a number of bytes is expected.
147 A number may end with
148 .L k
149 or
150 .LR b
151 to specify multiplication by
152 1024 or 512 respectively;
153 a pair of numbers may be separated by
154 .L x
155 to indicate a product.
156 Multiple conversions may be specified in the style:
157 .LR "-conv ebcdic,ucase" .
158 .PP
159 .L Cbs\^
160 is used only if
161 .LR ascii\^ ,
162 .LR unblock\^ ,
163 .LR ebcdic\^ ,
164 .LR ibm\^ ,
165 or
166 .L block\^
167 conversion is specified.
168 In the first two cases,
169 .I n
170 characters are copied into the conversion buffer, any specified
171 character mapping is done,
172 trailing blanks are trimmed and new-line is added
173 before sending the line to the output.
174 In the latter three cases, characters are read into the
175 conversion buffer and blanks are added to make up an
176 output record of size
177 .IR n .
178 If
179 .L cbs\^
180 is unspecified or zero, the
181 .LR ascii\^ ,
182 .LR ebcdic\^ ,
183 and
184 .L ibm\^
185 options convert the character set without changing the block
186 structure of the input file; the
187 .L unblock\^
188 and
189 .L block\^
190 options become a simple file copy.
191 .SH SOURCE
192 .B \*9/src/cmd/dd.c
193 .SH "SEE ALSO"
194 .MR cp (1)
195 .SH DIAGNOSTICS
196 .I Dd
197 reports the number of full + partial input and output
198 blocks handled.