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1.1 root 1: .\" Copyright (c) 1980 Regents of the University of California.
2: .\" All rights reserved. The Berkeley software License Agreement
3: .\" specifies the terms and conditions for redistribution.
4: .\"
5: .\" @(#)dd.1 6.1 (Berkeley) 4/29/85
6: .\"
7: .TH DD 1 "April 29, 1985"
8: .UC 4
9: .SH NAME
10: dd \- convert and copy a file
11: .SH SYNOPSIS
12: .B dd
13: [option=value] ...
14: .SH DESCRIPTION
15: .I Dd
16: copies the specified input file
17: to the specified output with
18: possible conversions.
19: The standard input and output are used by default.
20: The input and output block size may be
21: specified to take advantage of raw physical I/O.
22: .PP
23: .br
24: .ns
25: .TP 15
26: .I option
27: .I values
28: .br
29: .ns
30: .TP
31: if=
32: input file name; standard input is default
33: .br
34: .ns
35: .TP
36: of=
37: output file name; standard output is default
38: .br
39: .ns
40: .TP
41: .RI ibs= n
42: input block size
43: .I n
44: bytes (default 512)
45: .br
46: .ns
47: .TP
48: .RI obs= n
49: output block size (default 512)
50: .br
51: .ns
52: .TP
53: .RI bs= n
54: set both input and output block size,
55: superseding
56: .I ibs
57: and
58: .I obs;
59: also, if no conversion is specified,
60: it is particularly efficient since no copy need be done
61: .br
62: .ns
63: .TP
64: .RI cbs= n
65: conversion buffer size
66: .br
67: .ns
68: .TP
69: .RI skip= n
70: skip
71: .IR n ""
72: input records before starting copy
73: .br
74: .ns
75: .TP
76: .RI files= n
77: copy
78: .I n
79: input files before terminating (makes sense only
80: where input is a magtape or similar device).
81: .br
82: .ns
83: .TP
84: .RI seek= n
85: seek
86: .I n
87: records from beginning of output file before copying
88: .br
89: .ns
90: .TP
91: count=\fIn\fR
92: copy only
93: .IR n ""
94: input records
95: .br
96: .ns
97: .TP
98: conv=ascii
99: .ds h \h'\w'conv='u'
100: convert EBCDIC to ASCII
101: .br
102: .ns
103: .IP \*hebcdic
104: convert ASCII to EBCDIC
105: .br
106: .ns
107: .IP \*hibm
108: slightly different map of ASCII to EBCDIC
109: .br
110: .ns
111: .IP \*hblock
112: convert variable length records to fixed length
113: .br
114: .ns
115: .IP \*hunblock
116: convert fixed length records to variable length
117: .br
118: .ns
119: .IP \*hlcase
120: map alphabetics to lower case
121: .br
122: .ns
123: .IP \*hucase
124: map alphabetics to upper case
125: .br
126: .ns
127: .IP \*hswab
128: swap every pair of bytes
129: .br
130: .ns
131: .IP \*hnoerror
132: do not stop processing on an error
133: .br
134: .ns
135: .IP \*hsync
136: pad every input record to
137: .I ibs
138: .br
139: .ns
140: .IP "\*h... , ..."
141: several comma-separated conversions
142: .PP
143: .fi
144: Where sizes are specified,
145: a number of bytes is expected.
146: A number may end with
147: .B "k, b"
148: or
149: .B w
150: to specify multiplication by
151: 1024, 512, or 2 respectively;
152: a pair of numbers may be separated by
153: .B x
154: to indicate a product.
155: .PP
156: .I Cbs
157: is used only if
158: .I ascii,
159: .I unblock,
160: .I ebcdic,
161: .I ibm,
162: or
163: .I block
164: conversion is specified.
165: In the first two cases,
166: .I cbs
167: characters are placed into the conversion buffer, any specified
168: character mapping is done,
169: trailing blanks trimmed and new-line added
170: before sending the line to the output.
171: In the latter three cases, characters are read into the
172: conversion buffer, and blanks added
173: to make up an
174: output record of size
175: .IR cbs .
176: .PP
177: After completion,
178: .I dd
179: reports the number of whole and partial input and output
180: blocks.
181: .PP
182: For example, to read an EBCDIC tape blocked ten 80-byte
183: EBCDIC card images per record into the ASCII file
184: .I x:
185: .IP
186: .nf
187: dd if=/dev/rmt0 of=x ibs=800 cbs=80 conv=ascii,lcase
188: .fi
189: .PP
190: Note the use of raw magtape.
191: .I Dd
192: is especially suited to I/O on the raw
193: physical devices because it allows reading
194: and writing in arbitrary record sizes.
195: .SH "SEE ALSO"
196: cp(1), tr(1)
197: .SH DIAGNOSTICS
198: f+p records in(out): numbers of full and partial records read(written)
199: .SH BUGS
200: The ASCII/EBCDIC conversion tables are
201: taken
202: from the 256 character standard in
203: the CACM Nov, 1968.
204: The `ibm' conversion, while less blessed as a standard,
205: corresponds better to certain IBM print train conventions.
206: There is no universal solution.
207: .br
208: One must specify ``conv=noerror,sync'' when copying
209: raw disks with bad sectors to insure
210: .I dd
211: stays synchronized.
212: .PP
213: Certain combinations of arguments to
214: .I conv=
215: are permitted.
216: However, the
217: .I block
218: or
219: .I unblock
220: option cannot be combined with
221: .IR ascii ,
222: .IR ebcdic ""
223: or
224: .IR ibm .
225: Invalid combinations
226: .I "silently ignore"
227: all but the last mutually-exclusive keyword.
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