Commit | Line | Data |
---|---|---|
e6817382 BJ |
1 | .TH DD 1 |
2 | .SH NAME | |
3 | dd \- convert and copy a file | |
4 | .SH SYNOPSIS | |
5 | .B dd | |
6 | [option=value] ... | |
7 | .SH DESCRIPTION | |
8 | .I Dd | |
9 | copies the specified input file | |
10 | to the specified output with | |
11 | possible conversions. | |
12 | The standard input and output are used by default. | |
13 | The input and output block size may be | |
14 | specified to take advantage of raw physical I/O. | |
15 | .PP | |
16 | .br | |
17 | .ns | |
18 | .TP 15 | |
19 | .I option | |
20 | .I values | |
21 | .br | |
22 | .ns | |
23 | .TP | |
24 | if= | |
25 | input file name; standard input is default | |
26 | .br | |
27 | .ns | |
28 | .TP | |
29 | of= | |
30 | output file name; standard output is default | |
31 | .br | |
32 | .ns | |
33 | .TP | |
34 | .RI ibs= n | |
35 | input block size | |
36 | .I n | |
37 | bytes (default 512) | |
38 | .br | |
39 | .ns | |
40 | .TP | |
41 | .RI obs= n | |
42 | output block size (default 512) | |
43 | .br | |
44 | .ns | |
45 | .TP | |
46 | .RI bs= n | |
47 | set both input and output block size, | |
48 | superseding | |
49 | .I ibs | |
50 | and | |
51 | .I obs; | |
52 | also, if no conversion is specified, | |
53 | it is particularly efficient since no copy need be done | |
54 | .br | |
55 | .ns | |
56 | .TP | |
57 | .RI cbs= n | |
58 | conversion buffer size | |
59 | .br | |
60 | .ns | |
61 | .TP | |
62 | .RI skip= n | |
63 | skip | |
64 | .IR n "" | |
65 | input records before starting copy | |
66 | .br | |
67 | .ns | |
68 | .TP | |
69 | .RI files= n | |
70 | skip | |
71 | .I n | |
72 | input files before starting copy | |
73 | .br | |
74 | .ns | |
75 | .TP | |
76 | .RI seek= n | |
77 | seek | |
78 | .I n | |
79 | records from beginning of output file before copying | |
80 | .br | |
81 | .ns | |
82 | .TP | |
83 | count=\fIn\fR | |
84 | copy only | |
85 | .IR n "" | |
86 | input records | |
87 | .br | |
88 | .ns | |
89 | .TP | |
90 | conv=ascii | |
91 | .ds h \h'\w'conv='u' | |
92 | convert EBCDIC to ASCII | |
93 | .br | |
94 | .ns | |
95 | .IP \*hebcdic | |
96 | convert ASCII to EBCDIC | |
97 | .br | |
98 | .ns | |
99 | .IP \*hibm | |
100 | slightly different map of ASCII to EBCDIC | |
101 | .br | |
102 | .ns | |
103 | .IP \*hlcase | |
104 | map alphabetics to lower case | |
105 | .br | |
106 | .ns | |
107 | .IP \*hucase | |
108 | map alphabetics to upper case | |
109 | .br | |
110 | .ns | |
111 | .IP \*hswab | |
112 | swap every pair of bytes | |
113 | .br | |
114 | .ns | |
115 | .IP \*hnoerror | |
116 | do not stop processing on an error | |
117 | .br | |
118 | .ns | |
119 | .IP \*hsync | |
120 | pad every input record to | |
121 | .I ibs | |
122 | .br | |
123 | .ns | |
124 | .IP "\*h... , ..." | |
125 | several comma-separated conversions | |
126 | .PP | |
127 | .fi | |
128 | Where sizes are specified, | |
129 | a number of bytes is expected. | |
130 | A number may end with | |
131 | .B "k, b" | |
132 | or | |
133 | .B w | |
134 | to specify multiplication by | |
135 | 1024, 512, or 2 respectively; | |
136 | a pair of numbers may be separated by | |
137 | .B x | |
138 | to indicate a product. | |
139 | .PP | |
140 | .I Cbs | |
141 | is used only if | |
142 | .I ascii | |
143 | or | |
144 | .I ebcdic | |
145 | conversion is specified. | |
146 | In the former case | |
147 | .I cbs | |
148 | characters are placed into the conversion buffer, converted to | |
149 | ASCII, and trailing blanks trimmed and new-line added | |
150 | before sending the line to the output. | |
151 | In the latter case ASCII characters are read into the | |
152 | conversion buffer, converted to EBCDIC, and blanks added | |
153 | to make up an | |
154 | output record of size | |
155 | .IR cbs . | |
156 | .PP | |
157 | After completion, | |
158 | .I dd | |
159 | reports the number of whole and partial input and output | |
160 | blocks. | |
161 | .PP | |
162 | For example, to read an EBCDIC tape blocked ten 80-byte | |
163 | EBCDIC card images per record into the ASCII file | |
164 | .I x: | |
165 | .IP | |
166 | .nf | |
167 | dd if=/dev/rmt0 of=x ibs=800 cbs=80 conv=ascii,lcase | |
168 | .fi | |
169 | .PP | |
170 | Note the use of raw magtape. | |
171 | .I Dd | |
172 | is especially suited to I/O on the raw | |
173 | physical devices because it allows reading | |
174 | and writing in arbitrary record sizes. | |
175 | .SH "SEE ALSO" | |
176 | cp(1), tr(1) | |
177 | .SH DIAGNOSTICS | |
178 | f+p records in(out): numbers of full and partial records read(written) | |
179 | .SH BUGS | |
180 | The ASCII/EBCDIC conversion tables are | |
181 | taken | |
182 | from the 256 character standard in | |
183 | the CACM Nov, 1968. | |
184 | The `ibm' conversion, while less blessed as a standard, | |
185 | corresponds better to certain IBM print train conventions. | |
186 | There is no universal solution. | |
187 | .PP | |
188 | Newlines are inserted only on conversion to ASCII; | |
189 | padding is done only on conversion to EBCDIC. | |
190 | These should be separate options. |