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--- old/usr/src/man/man1m/dd.1m
+++ new/usr/src/man/man1m/dd.1m
1 1 '\" te
2 2 .\" Copyright (c) 1992, X/Open Company Limited All Rights Reserved
3 3 .\" Copyright 1989 AT&T
4 4 .\" Portions Copyright (c) 1995, Sun Microsystems, Inc. All Rights Reserved
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12 12 .TH DD 1M "Sep 16, 1996"
13 13 .SH NAME
14 14 dd \- convert and copy a file
15 15 .SH SYNOPSIS
16 16 .LP
17 17 .nf
18 18 \fB/usr/bin/dd\fR [\fIoperand=value\fR]...
19 19 .fi
20 20
21 21 .SH DESCRIPTION
22 22 .sp
23 23 .LP
24 24 The \fBdd\fR utility copies the specified input file to the specified output
25 25 with possible conversions. The standard input and output are used by default.
26 26 The input and output block sizes may be specified to take advantage of raw
27 27 physical I/O. Sizes are specified in bytes; a number may end with \fBk\fR,
28 28 \fBb\fR, or \fBw\fR to specify multiplication by 1024, 512, or 2, respectively.
29 29 Numbers may also be separated by \fBx\fR to indicate multiplication.
30 30 .sp
31 31 .LP
32 32 The \fBdd\fR utility reads the input one block at a time, using the specified
33 33 input block size. \fBdd\fR then processes the block of data actually returned,
34 34 which could be smaller than the requested block size. \fBdd\fR applies any
35 35 conversions that have been specified and writes the resulting data to the
36 36 output in blocks of the specified output block size.
37 37 .sp
38 38 .LP
39 39 \fBcbs\fR is used only if \fBascii\fR, \fBasciib\fR, \fBunblock\fR,
40 40 \fBebcdic\fR, \fBebcdicb\fR, \fBibm\fR, \fBibmb\fR, or \fBblock\fR conversion
41 41 is specified. In the first two cases, \fBcbs\fR characters are copied into the
42 42 conversion buffer, any specified character mapping is done, trailing blanks are
43 43 trimmed, and a \fBNEWLINE\fR is added before sending the line to output. In the
44 44 last three cases, characters up to \fBNEWLINE\fR are read into the conversion
45 45 buffer and blanks are added to make up an output record of size \fBcbs\fR.
46 46 \fBASCII\fR files are presumed to contain \fBNEWLINE\fR characters. If
47 47 \fBcbs\fR is unspecified or \fB0\fR, the \fBascii\fR, \fBasciib\fR,
48 48 \fBebcdic\fR, \fBebcdicb\fR, \fBibm\fR, and \fBibmb\fR options convert the
49 49 character set without changing the input file's block structure. The
50 50 \fBunblock\fR and \fBblock\fR options become a simple file copy.
51 51 .sp
52 52 .LP
53 53 After completion, \fBdd\fR reports the number of whole and partial input and
54 54 output blocks.
55 55 .SH OPERANDS
56 56 .sp
57 57 .LP
58 58 The following operands are supported:
59 59 .sp
60 60 .ne 2
61 61 .na
62 62 \fB\fBif=\fR\fIfile\fR\fR
63 63 .ad
64 64 .sp .6
65 65 .RS 4n
66 66 Specifies the input path. Standard input is the default.
67 67 .RE
68 68
69 69 .sp
70 70 .ne 2
71 71 .na
72 72 \fB\fBof=\fR\fIfile\fR\fR
73 73 .ad
74 74 .sp .6
75 75 .RS 4n
76 76 Specifies the output path. Standard output is the default. If the
77 77 \fBseek=\fR\fBexpr\fR conversion is not also specified, the output file will be
78 78 truncated before the copy begins, unless \fBconv=notrunc\fR is specified. If
79 79 \fBseek=\fR\fBexpr\fR is specified, but \fBconv=notrunc\fR is not, the effect
80 80 of the copy will be to preserve the blocks in the output file over which
81 81 \fBdd\fR seeks, but no other portion of the output file will be preserved. (If
82 82 the size of the seek plus the size of the input file is less than the previous
83 83 size of the output file, the output file is shortened by the copy.)
84 84 .RE
85 85
86 86 .sp
87 87 .ne 2
88 88 .na
89 89 \fB\fBibs=\fR\fIn\fR\fR
90 90 .ad
91 91 .sp .6
92 92 .RS 4n
93 93 Specifies the input block size in \fIn\fR bytes (default is \fB512\fR).
94 94 .RE
95 95
96 96 .sp
97 97 .ne 2
98 98 .na
99 99 \fB\fBobs=\fR\fIn\fR\fR
100 100 .ad
101 101 .sp .6
102 102 .RS 4n
103 103 Specifies the output block size in \fIn\fR bytes (default is \fB512\fR).
104 104 .RE
105 105
106 106 .sp
107 107 .ne 2
108 108 .na
109 109 \fB\fBbs=\fR\fIn\fR\fR
110 110 .ad
111 111 .sp .6
112 112 .RS 4n
113 113 Sets both input and output block sizes to \fIn\fR bytes, superseding \fBibs=\fR
114 114 and \fBobs=\fR. If no conversion other than \fBsync\fR,\fB noerror\fR, and
115 115 \fBnotrunc\fR is specified, each input block is copied to the output as a
116 116 single block without aggregating short blocks.
117 117 .RE
118 118
119 119 .sp
120 120 .ne 2
121 121 .na
122 122 \fB\fBcbs=\fR\fIn\fR\fR
123 123 .ad
124 124 .sp .6
125 125 .RS 4n
126 126 Specifies the conversion block size for \fBblock\fR and \fBunblock\fR in bytes
127 127 by \fIn\fR (default is \fB0\fR). If \fBcbs=\fR is omitted or given a value of
128 128 \fB0\fR, using \fBblock\fR or \fBunblock\fR produces unspecified results.
129 129 .sp
130 130 This option is used only if \fBASCII\fR or \fBEBCDIC\fR conversion is
131 131 specified. For the \fBascii\fR and \fBasciib\fR operands, the input is handled
132 132 as described for the \fBunblock\fR operand except that characters are converted
133 133 to \fBASCII\fR before the trailing \fBSPACE\fR characters are deleted. For the
134 134 \fBebcdic\fR, \fBebcdicb\fR, \fBibm\fR, and \fBibmb\fR operands, the input is
135 135 handled as described for the \fBblock\fR operand except that the characters are
136 136 converted to \fBEBCDIC\fR or IBM \fBEBCDIC\fR after the trailing \fBSPACE\fR
137 137 characters are added.
138 138 .RE
139 139
140 140 .sp
141 141 .ne 2
142 142 .na
143 143 \fB\fBfiles=\fR\fIn\fR\fR
144 144 .ad
145 145 .sp .6
146 146 .RS 4n
147 147 Copies and concatenates \fIn\fR input files before terminating (makes sense
148 148 only where input is a magnetic tape or similar device).
149 149 .RE
150 150
151 151 .sp
152 152 .ne 2
153 153 .na
154 154 \fB\fBskip=\fR\fIn\fR\fR
155 155 .ad
156 156 .sp .6
157 157 .RS 4n
158 158 Skips \fIn\fR input blocks (using the specified input block size) before
159 159 starting to copy. On seekable files, the implementation reads the blocks or
160 160 seeks past them. On non-seekable files, the blocks are read and the data is
161 161 discarded.
162 162 .RE
163 163
164 164 .sp
165 165 .ne 2
166 166 .na
167 167 \fB\fBiseek=\fR\fIn\fR\fR
168 168 .ad
169 169 .sp .6
170 170 .RS 4n
171 171 Seeks \fIn\fR blocks from beginning of input file before copying (appropriate
172 172 for disk files, where \fBskip\fR can be incredibly slow).
173 173 .RE
174 174
175 175 .sp
176 176 .ne 2
177 177 .na
178 178 \fB\fBoseek=\fR\fIn\fR\fR
179 179 .ad
180 180 .sp .6
181 181 .RS 4n
182 182 Seeks \fIn\fR blocks from beginning of output file before copying.
183 183 .RE
184 184
185 185 .sp
186 186 .ne 2
187 187 .na
188 188 \fB\fBseek=\fR\fIn\fR\fR
189 189 .ad
190 190 .sp .6
191 191 .RS 4n
192 192 Skips \fIn\fR blocks (using the specified output block size) from beginning of
193 193 output file before copying. On non-seekable files, existing blocks are read and
194 194 space from the current end-of-file to the specified offset, if any, is filled
195 195 with null bytes. On seekable files, the implementation seeks to the specified
196 196 offset or reads the blocks as described for non-seekable files.
197 197 .RE
198 198
199 199 .sp
200 200 .ne 2
201 201 .na
202 202 \fB\fBcount=\fR\fIn\fR\fR
203 203 .ad
204 204 .sp .6
205 205 .RS 4n
206 206 Copies only \fIn\fR input blocks.
207 207 .RE
208 208
209 209 .sp
210 210 .ne 2
211 211 .na
212 212 \fB\fBconv=\fR\fIvalue\fR[\fB,\fR\fIvalue\fR.\|.\|.\|]\fR
213 213 .ad
214 214 .sp .6
215 215 .RS 4n
216 216 Where \fIvalue\fRs are comma-separated symbols from the following list:
217 217 .sp
218 218 .ne 2
219 219 .na
220 220 \fB\fBascii\fR\fR
221 221 .ad
222 222 .RS 11n
223 223 Converts \fBEBCDIC\fR to \fBASCII\fR.
224 224 .RE
225 225
226 226 .sp
227 227 .ne 2
228 228 .na
229 229 \fB\fBasciib\fR\fR
230 230 .ad
231 231 .RS 11n
232 232 Converts \fBEBCDIC\fR to \fBASCII\fR using \fBBSD\fR-compatible character
233 233 translations.
234 234 .RE
235 235
236 236 .sp
237 237 .ne 2
238 238 .na
239 239 \fB\fBebcdic\fR\fR
240 240 .ad
241 241 .RS 11n
242 242 Converts \fBASCII\fR to \fBEBCDIC\fR. If converting fixed-length \fBASCII\fR
243 243 records without NEWLINEs, sets up a pipeline with \fBdd conv=unblock\fR
244 244 beforehand.
245 245 .RE
246 246
247 247 .sp
248 248 .ne 2
249 249 .na
250 250 \fB\fBebcdicb\fR\fR
251 251 .ad
252 252 .RS 11n
253 253 Converts \fBASCII\fR to \fBEBCDIC\fR using \fBBSD\fR-compatible character
254 254 translations. If converting fixed-length \fBASCII\fR records without
255 255 \fBNEWLINE\fRs, sets up a pipeline with \fBdd conv=unblock\fR beforehand.
256 256 .RE
257 257
258 258 .sp
259 259 .ne 2
260 260 .na
261 261 \fB\fBibm\fR\fR
262 262 .ad
263 263 .RS 11n
264 264 Slightly different map of \fBASCII\fR to \fBEBCDIC\fR. If converting
265 265 fixed-length \fBASCII\fR records without \fBNEWLINE\fRs, sets up a pipeline
266 266 with \fBdd conv=unblock\fR beforehand.
267 267 .RE
268 268
269 269 .sp
270 270 .ne 2
271 271 .na
272 272 \fB\fBibmb\fR\fR
273 273 .ad
274 274 .RS 11n
275 275 Slightly different map of \fBASCII\fR to \fBEBCDIC\fR using
276 276 \fBBSD\fR-compatible character translations. If converting fixed-length
277 277 \fBASCII\fR records without \fBNEWLINE\fRs, sets up a pipeline with \fBdd
278 278 conv=unblock\fR beforehand.
279 279 .RE
280 280
281 281 The \fBascii\fR (or \fBasciib\fR), \fBebcdic\fR (or \fBebcdicb\fR), and
282 282 \fBibm\fR (or \fBibmb\fR) values are mutually exclusive.
283 283 .sp
284 284 .ne 2
285 285 .na
286 286 \fB\fBblock\fR\fR
287 287 .ad
288 288 .RS 11n
289 289 Treats the input as a sequence of \fBNEWLINE\fR-terminated or
290 290 \fBEOF\fR-terminated variable-length records independent of the input block
291 291 boundaries. Each record is converted to a record with a fixed length specified
292 292 by the conversion block size. Any \fBNEWLINE\fR character is removed from the
293 293 input line. \fBSPACE\fR characters are appended to lines that are shorter than
294 294 their conversion block size to fill the block. Lines that are longer than the
295 295 conversion block size are truncated to the largest number of characters that
296 296 will fit into that size. The number of truncated lines is reported.
297 297 .RE
298 298
299 299 .sp
300 300 .ne 2
301 301 .na
302 302 \fB\fBunblock\fR\fR
303 303 .ad
304 304 .RS 11n
305 305 Converts fixed-length records to variable length. Reads a number of bytes equal
306 306 to the conversion block size (or the number of bytes remaining in the input, if
307 307 less than the conversion block size), delete all trailing \fBSPACE\fR
308 308 characters, and append a \fBNEWLINE\fR character.
309 309 .RE
310 310
311 311 The \fBblock\fR and \fBunblock\fR values are mutually exclusive.
312 312 .sp
313 313 .ne 2
314 314 .na
315 315 \fB\fBlcase\fR\fR
316 316 .ad
317 317 .RS 9n
318 318 Maps upper-case characters specified by the \fBLC_CTYPE\fR keyword
319 319 \fBtolower\fR to the corresponding lower-case character. Characters for which
320 320 no mapping is specified are not modified by this conversion.
321 321 .RE
322 322
323 323 .sp
324 324 .ne 2
325 325 .na
326 326 \fB\fBucase\fR\fR
327 327 .ad
328 328 .RS 9n
329 329 Maps lower-case characters specified by the \fBLC_CTYPE\fR keyword
330 330 \fBtoupper\fR to the corresponding upper-case character. Characters for which
331 331 no mapping is specified are not modified by this conversion.
332 332 .RE
333 333
334 334 The \fBlcase\fR and \fBucase\fR symbols are mutually exclusive.
335 335 .sp
336 336 .ne 2
337 337 .na
338 338 \fB\fBswab\fR\fR
339 339 .ad
340 340 .RS 11n
341 341 Swaps every pair of input bytes. If the current input record is an odd number
342 342 of bytes, the last byte in the input record is ignored.
343 343 .RE
344 344
345 345 .sp
346 346 .ne 2
347 347 .na
348 348 \fB\fBnoerror\fR\fR
349 349 .ad
350 350 .RS 11n
351 351 Does not stop processing on an input error. When an input error occurs, a
352 352 diagnostic message is written on standard error, followed by the current input
353 353 and output block counts in the same format as used at completion. If the
354 354 \fBsync\fR conversion is specified, the missing input is replaced with null
355 355 bytes and processed normally. Otherwise, the input block will be omitted from
356 356 the output.
357 357 .RE
358 358
359 359 .sp
360 360 .ne 2
361 361 .na
362 362 \fB\fBnotrunc\fR\fR
363 363 .ad
364 364 .RS 11n
365 365 Does not truncate the output file. Preserves blocks in the output file not
366 366 explicitly written by this invocation of \fBdd\fR. (See also the preceding
367 367 \fBof=\fR\fIfile\fR operand.)
368 368 .RE
369 369
370 370 .sp
371 371 .ne 2
372 372 .na
373 373 \fB\fBsync\fR\fR
374 374 .ad
375 375 .RS 11n
376 376 Pads every input block to the size of the \fBibs=\fR buffer, appending null
377 377 bytes. (If either \fBblock\fR or \fBunblock\fR is also specified, appends
378 378 \fBSPACE\fR characters, rather than null bytes.)
379 379 .RE
380 380
381 381 .RE
382 382
383 383 .sp
384 384 .LP
385 385 If operands other than \fBconv=\fR are specified more than once, the last
386 386 specified \fBoperand=\fR\fIvalue\fR is used.
387 387 .sp
388 388 .LP
389 389 For the \fBbs=\fR, \fBcbs=\fR, \fBibs=\fR, and \fBobs=\fR operands, the
390 390 application must supply an expression specifying a size in bytes. The
391 391 expression, \fBexpr\fR, can be:
392 392 .RS +4
393 393 .TP
394 394 1.
395 395 a positive decimal number
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396 396 .RE
397 397 .RS +4
398 398 .TP
399 399 2.
400 400 a positive decimal number followed by \fBk\fR, specifying multiplication by
401 401 1024
402 402 .RE
403 403 .RS +4
404 404 .TP
405 405 3.
406 +a positive decimal number followed by \fBM\fR, specifying multiplication by
407 +1024*1024
408 +.RE
409 +.RS +4
410 +.TP
411 +4.
412 +a positive decimal number followed by \fBG\fR, specifying multiplication by
413 +1024*1024*1024
414 +.RE
415 +.RS +4
416 +.TP
417 +5.
418 +a positive decimal number followed by \fBT\fR, specifying multiplication by
419 +1024*1024*1024*1024
420 +.RE
421 +.RS +4
422 +.TP
423 +6.
424 +a positive decimal number followed by \fBP\fR, specifying multiplication by
425 +1024*1024*1024*1024*1024
426 +.RE
427 +.RS +4
428 +.TP
429 +7.
430 +a positive decimal number followed by \fBE\fR, specifying multiplication by
431 +1024*1024*1024*1024*1024*1024
432 +.RE
433 +.RS +4
434 +.TP
435 +8.
436 +a positive decimal number followed by \fBZ\fR, specifying multiplication by
437 +1024*1024*1024*1024*1024*1024*1024
438 +.RE
439 +.RS +4
440 +.TP
441 +9.
406 442 a positive decimal number followed by \fBb\fR, specifying multiplication by
407 443 512
408 444 .RE
409 445 .RS +4
410 446 .TP
411 -4.
447 +10.
412 448 two or more positive decimal numbers (with or without \fBk\fR or \fBb\fR)
413 449 separated by \fBx\fR, specifying the product of the indicated values.
414 450 .RE
415 451 .sp
416 452 .LP
417 453 All of the operands will be processed before any input is read.
418 454 .SH USAGE
419 455 .sp
420 456 .LP
421 457 See \fBlargefile\fR(5) for the description of the behavior of \fBdd\fR when
422 458 encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
423 459 .SH EXAMPLES
424 460 .LP
425 461 \fBExample 1 \fRCopying from one tape drive to another
426 462 .sp
427 463 .LP
428 464 The following example copies from tape drive \fB0\fR to tape drive \fB1\fR,
429 465 using a common historical device naming convention.
430 466
431 467 .sp
432 468 .in +2
433 469 .nf
434 470 example% \fBdd if=/dev/rmt/0h of=/dev/rmt/1h\fR
435 471 .fi
436 472 .in -2
437 473 .sp
438 474
439 475 .LP
440 476 \fBExample 2 \fRStripping the first 10 bytes from standard input
441 477 .sp
442 478 .LP
443 479 The following example strips the first 10 bytes from standard input:
444 480
445 481 .sp
446 482 .in +2
447 483 .nf
448 484 example% \fBdd ibs=10 skip=1\fR
449 485 .fi
450 486 .in -2
451 487 .sp
452 488
453 489 .LP
454 490 \fBExample 3 \fRReading a tape into an ASCII file
455 491 .sp
456 492 .LP
457 493 This example reads an \fBEBCDIC\fR tape blocked ten 80-byte \fBEBCDIC\fR card
458 494 images per block into the \fBASCII\fR file \fBx\fR:
459 495
460 496 .sp
461 497 .in +2
462 498 .nf
463 499 example% \fBdd if=/dev/tape of=x ibs=800 cbs=80 conv=ascii,lcase\fR
464 500 .fi
465 501 .in -2
466 502 .sp
467 503
468 504 .LP
469 505 \fBExample 4 \fRUsing conv=sync to write to tape
470 506 .sp
471 507 .LP
472 508 The following example uses \fBconv=sync\fR when writing to a tape:
473 509
474 510 .sp
475 511 .in +2
476 512 .nf
477 513 example% \fBtar cvf - . | compress | dd obs=1024k of=/dev/rmt/0 conv=sync\fR
478 514 .fi
479 515 .in -2
480 516 .sp
481 517
482 518 .SH ENVIRONMENT VARIABLES
483 519 .sp
484 520 .LP
485 521 See \fBenviron\fR(5) for descriptions of the following environment variables
486 522 that affect the execution of \fBdd\fR: \fBLANG\fR, \fBLC_ALL\fR,
487 523 \fBLC_CTYPE\fR, \fBLC_MESSAGES\fR, and \fBNLSPATH\fR.
488 524 .SH EXIT STATUS
489 525 .sp
490 526 .LP
491 527 The following exit values are returned:
492 528 .sp
493 529 .ne 2
494 530 .na
495 531 \fB\fB0\fR\fR
496 532 .ad
497 533 .RS 6n
498 534 The input file was copied successfully.
499 535 .RE
500 536
501 537 .sp
502 538 .ne 2
503 539 .na
504 540 \fB\fB>0\fR\fR
505 541 .ad
506 542 .RS 6n
507 543 An error occurred.
508 544 .RE
509 545
510 546 .sp
511 547 .LP
512 548 If an input error is detected and the \fBnoerror\fR conversion has not been
513 549 specified, any partial output block will be written to the output file, a
514 550 diagnostic message will be written, and the copy operation will be
515 551 discontinued. If some other error is detected, a diagnostic message will be
516 552 written and the copy operation will be discontinued.
517 553 .SH ATTRIBUTES
518 554 .sp
519 555 .LP
520 556 See \fBattributes\fR(5) for descriptions of the following attributes:
521 557 .sp
522 558
523 559 .sp
524 560 .TS
525 561 box;
526 562 c | c
527 563 l | l .
528 564 ATTRIBUTE TYPE ATTRIBUTE VALUE
529 565 _
530 566 Interface Stability Standard
531 567 .TE
532 568
533 569 .SH SEE ALSO
534 570 .sp
535 571 .LP
536 572 \fBcp\fR(1), \fBsed\fR(1), \fBtr\fR(1), \fBattributes\fR(5), \fBenviron\fR(5),
537 573 \fBlargefile\fR(5), \fBstandards\fR(5)
538 574 .SH DIAGNOSTICS
539 575 .sp
540 576 .ne 2
541 577 .na
542 578 \fB\fBf+p records in(out)\fR\fR
543 579 .ad
544 580 .RS 23n
545 581 numbers of full and partial blocks read(written)
546 582 .RE
547 583
548 584 .SH NOTES
549 585 .sp
550 586 .LP
551 587 Do not use \fBdd\fR to copy files between file systems having different block
552 588 sizes.
553 589 .sp
554 590 .LP
555 591 Using a blocked device to copy a file will result in extra nulls being added
556 592 to the file to pad the final block to the block boundary.
557 593 .sp
558 594 .LP
559 595 When \fBdd\fR reads from a pipe, using the \fBibs=X\fR and \fBobs=Y\fR
560 596 operands, the output will always be blocked in chunks of size Y. When
561 597 \fBbs=Z\fR is used, the output blocks will be whatever was available to be read
562 598 from the pipe at the time.
563 599 .sp
564 600 .LP
565 601 When using \fBdd\fR to copy files to a tape device, the file size must be a
566 602 multiple of the device sector size (for example, 512 Kbyte). To copy files of
567 603 arbitrary size to a tape device, use \fBtar\fR(1) or \fBcpio\fR(1).
568 604 .sp
569 605 .LP
570 606 For \fBSIGINT\fR, \fBdd\fR writes status information to standard error before
571 607 exiting. It takes the standard action for all other signals.
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