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--- old/usr/src/man/man1m/dd.1m
+++ new/usr/src/man/man1m/dd.1m
1 1 '\" te
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13 13 .TH DD 1M "Jan 04, 2014"
14 14 .SH NAME
15 15 dd \- convert and copy a file
16 16 .SH SYNOPSIS
17 17 .LP
18 18 .nf
19 19 \fB/usr/bin/dd\fR [\fIoperand=value\fR]...
20 20 .fi
21 21
22 22 .SH DESCRIPTION
23 23 .sp
24 24 .LP
25 25 The \fBdd\fR utility copies the specified input file to the specified output
26 26 with possible conversions. The standard input and output are used by default.
27 27 The input and output block sizes may be specified to take advantage of raw
28 28 physical I/O. Sizes are specified in bytes; a number may end with \fBk\fR,
29 29 \fBb\fR, or \fBw\fR to specify multiplication by 1024, 512, or 2, respectively.
30 30 Numbers may also be separated by \fBx\fR to indicate multiplication.
31 31 .sp
32 32 .LP
33 33 The \fBdd\fR utility reads the input one block at a time, using the specified
34 34 input block size. \fBdd\fR then processes the block of data actually returned,
35 35 which could be smaller than the requested block size. \fBdd\fR applies any
36 36 conversions that have been specified and writes the resulting data to the
37 37 output in blocks of the specified output block size.
38 38 .sp
39 39 .LP
40 40 \fBcbs\fR is used only if \fBascii\fR, \fBasciib\fR, \fBunblock\fR,
41 41 \fBebcdic\fR, \fBebcdicb\fR, \fBibm\fR, \fBibmb\fR, or \fBblock\fR conversion
42 42 is specified. In the first two cases, \fBcbs\fR characters are copied into the
43 43 conversion buffer, any specified character mapping is done, trailing blanks are
44 44 trimmed, and a \fBNEWLINE\fR is added before sending the line to output. In the
45 45 last three cases, characters up to \fBNEWLINE\fR are read into the conversion
46 46 buffer and blanks are added to make up an output record of size \fBcbs\fR.
47 47 \fBASCII\fR files are presumed to contain \fBNEWLINE\fR characters. If
48 48 \fBcbs\fR is unspecified or \fB0\fR, the \fBascii\fR, \fBasciib\fR,
49 49 \fBebcdic\fR, \fBebcdicb\fR, \fBibm\fR, and \fBibmb\fR options convert the
50 50 character set without changing the input file's block structure. The
51 51 \fBunblock\fR and \fBblock\fR options become a simple file copy.
52 52 .sp
53 53 .LP
54 54 After completion, \fBdd\fR reports the number of whole and partial input and
55 55 output blocks.
56 56 .SH OPERANDS
57 57 .sp
58 58 .LP
59 59 The following operands are supported:
60 60 .sp
61 61 .ne 2
62 62 .na
63 63 \fB\fBif=\fR\fIfile\fR\fR
64 64 .ad
65 65 .sp .6
66 66 .RS 4n
67 67 Specifies the input path. Standard input is the default.
68 68 .RE
69 69
70 70 .sp
71 71 .ne 2
72 72 .na
73 73 \fB\fBof=\fR\fIfile\fR\fR
74 74 .ad
75 75 .sp .6
76 76 .RS 4n
77 77 Specifies the output path. Standard output is the default. If the
78 78 \fBseek=\fR\fBexpr\fR conversion is not also specified, the output file will be
79 79 truncated before the copy begins, unless \fBconv=notrunc\fR is specified. If
80 80 \fBseek=\fR\fBexpr\fR is specified, but \fBconv=notrunc\fR is not, the effect
81 81 of the copy will be to preserve the blocks in the output file over which
82 82 \fBdd\fR seeks, but no other portion of the output file will be preserved. (If
83 83 the size of the seek plus the size of the input file is less than the previous
84 84 size of the output file, the output file is shortened by the copy.)
85 85 .RE
86 86
87 87 .sp
88 88 .ne 2
89 89 .na
90 90 \fB\fBibs=\fR\fIn\fR\fR
91 91 .ad
92 92 .sp .6
93 93 .RS 4n
94 94 Specifies the input block size in \fIn\fR bytes (default is \fB512\fR).
95 95 .RE
96 96
97 97 .sp
98 98 .ne 2
99 99 .na
100 100 \fB\fBobs=\fR\fIn\fR\fR
101 101 .ad
102 102 .sp .6
103 103 .RS 4n
104 104 Specifies the output block size in \fIn\fR bytes (default is \fB512\fR).
105 105 .RE
106 106
107 107 .sp
108 108 .ne 2
109 109 .na
110 110 \fB\fBbs=\fR\fIn\fR\fR
111 111 .ad
112 112 .sp .6
113 113 .RS 4n
114 114 Sets both input and output block sizes to \fIn\fR bytes, superseding \fBibs=\fR
115 115 and \fBobs=\fR. If no conversion other than \fBsync\fR,\fB noerror\fR, and
116 116 \fBnotrunc\fR is specified, each input block is copied to the output as a
117 117 single block without aggregating short blocks.
118 118 .RE
119 119
120 120 .sp
121 121 .ne 2
122 122 .na
123 123 \fB\fBcbs=\fR\fIn\fR\fR
124 124 .ad
125 125 .sp .6
126 126 .RS 4n
127 127 Specifies the conversion block size for \fBblock\fR and \fBunblock\fR in bytes
128 128 by \fIn\fR (default is \fB0\fR). If \fBcbs=\fR is omitted or given a value of
129 129 \fB0\fR, using \fBblock\fR or \fBunblock\fR produces unspecified results.
130 130 .sp
131 131 This option is used only if \fBASCII\fR or \fBEBCDIC\fR conversion is
132 132 specified. For the \fBascii\fR and \fBasciib\fR operands, the input is handled
133 133 as described for the \fBunblock\fR operand except that characters are converted
134 134 to \fBASCII\fR before the trailing \fBSPACE\fR characters are deleted. For the
135 135 \fBebcdic\fR, \fBebcdicb\fR, \fBibm\fR, and \fBibmb\fR operands, the input is
136 136 handled as described for the \fBblock\fR operand except that the characters are
137 137 converted to \fBEBCDIC\fR or IBM \fBEBCDIC\fR after the trailing \fBSPACE\fR
138 138 characters are added.
139 139 .RE
140 140
141 141 .sp
142 142 .ne 2
143 143 .na
144 144 \fB\fBfiles=\fR\fIn\fR\fR
145 145 .ad
146 146 .sp .6
147 147 .RS 4n
148 148 Copies and concatenates \fIn\fR input files before terminating (makes sense
149 149 only where input is a magnetic tape or similar device).
150 150 .RE
151 151
152 152 .sp
153 153 .ne 2
154 154 .na
155 155 \fB\fBskip=\fR\fIn\fR\fR
156 156 .ad
157 157 .sp .6
158 158 .RS 4n
159 159 Skips \fIn\fR input blocks (using the specified input block size) before
160 160 starting to copy. On seekable files, the implementation reads the blocks or
161 161 seeks past them. On non-seekable files, the blocks are read and the data is
162 162 discarded.
163 163 .RE
164 164
165 165 .sp
166 166 .ne 2
167 167 .na
168 168 \fB\fBiseek=\fR\fIn\fR\fR
169 169 .ad
170 170 .sp .6
171 171 .RS 4n
172 172 Seeks \fIn\fR blocks from beginning of input file before copying (appropriate
173 173 for disk files, where \fBskip\fR can be incredibly slow).
174 174 .RE
175 175
176 176 .sp
177 177 .ne 2
178 178 .na
179 179 \fB\fBoseek=\fR\fIn\fR\fR
180 180 .ad
181 181 .sp .6
182 182 .RS 4n
183 183 Seeks \fIn\fR blocks from beginning of output file before copying.
184 184 .RE
185 185
186 186 .sp
187 187 .ne 2
188 188 .na
189 189 \fB\fBseek=\fR\fIn\fR\fR
190 190 .ad
191 191 .sp .6
192 192 .RS 4n
193 193 Skips \fIn\fR blocks (using the specified output block size) from beginning of
194 194 output file before copying. On non-seekable files, existing blocks are read and
195 195 space from the current end-of-file to the specified offset, if any, is filled
196 196 with null bytes. On seekable files, the implementation seeks to the specified
197 197 offset or reads the blocks as described for non-seekable files.
198 198 .RE
199 199
200 200 .sp
201 201 .ne 2
202 202 .na
203 203 \fB\fBcount=\fR\fIn\fR\fR
204 204 .ad
205 205 .sp .6
206 206 .RS 4n
207 207 Copies only \fIn\fR input blocks.
208 208 .RE
209 209
210 210 .sp
211 211 .ne 2
212 212 .na
213 213 \fB\fBconv=\fR\fIvalue\fR[\fB,\fR\fIvalue\fR.\|.\|.\|]\fR
214 214 .ad
215 215 .sp .6
216 216 .RS 4n
217 217 Where \fIvalue\fRs are comma-separated symbols from the following list:
218 218 .sp
219 219 .ne 2
220 220 .na
221 221 \fB\fBascii\fR\fR
222 222 .ad
223 223 .RS 11n
224 224 Converts \fBEBCDIC\fR to \fBASCII\fR.
225 225 .RE
226 226
227 227 .sp
228 228 .ne 2
229 229 .na
230 230 \fB\fBasciib\fR\fR
231 231 .ad
232 232 .RS 11n
233 233 Converts \fBEBCDIC\fR to \fBASCII\fR using \fBBSD\fR-compatible character
234 234 translations.
235 235 .RE
236 236
237 237 .sp
238 238 .ne 2
239 239 .na
240 240 \fB\fBebcdic\fR\fR
241 241 .ad
242 242 .RS 11n
243 243 Converts \fBASCII\fR to \fBEBCDIC\fR. If converting fixed-length \fBASCII\fR
244 244 records without NEWLINEs, sets up a pipeline with \fBdd conv=unblock\fR
245 245 beforehand.
246 246 .RE
247 247
248 248 .sp
249 249 .ne 2
250 250 .na
251 251 \fB\fBebcdicb\fR\fR
252 252 .ad
253 253 .RS 11n
254 254 Converts \fBASCII\fR to \fBEBCDIC\fR using \fBBSD\fR-compatible character
255 255 translations. If converting fixed-length \fBASCII\fR records without
256 256 \fBNEWLINE\fRs, sets up a pipeline with \fBdd conv=unblock\fR beforehand.
257 257 .RE
258 258
259 259 .sp
260 260 .ne 2
261 261 .na
262 262 \fB\fBibm\fR\fR
263 263 .ad
264 264 .RS 11n
265 265 Slightly different map of \fBASCII\fR to \fBEBCDIC\fR. If converting
266 266 fixed-length \fBASCII\fR records without \fBNEWLINE\fRs, sets up a pipeline
267 267 with \fBdd conv=unblock\fR beforehand.
268 268 .RE
269 269
270 270 .sp
271 271 .ne 2
272 272 .na
273 273 \fB\fBibmb\fR\fR
274 274 .ad
275 275 .RS 11n
276 276 Slightly different map of \fBASCII\fR to \fBEBCDIC\fR using
277 277 \fBBSD\fR-compatible character translations. If converting fixed-length
278 278 \fBASCII\fR records without \fBNEWLINE\fRs, sets up a pipeline with \fBdd
279 279 conv=unblock\fR beforehand.
280 280 .RE
281 281
282 282 The \fBascii\fR (or \fBasciib\fR), \fBebcdic\fR (or \fBebcdicb\fR), and
283 283 \fBibm\fR (or \fBibmb\fR) values are mutually exclusive.
284 284 .sp
285 285 .ne 2
286 286 .na
287 287 \fB\fBblock\fR\fR
288 288 .ad
289 289 .RS 11n
290 290 Treats the input as a sequence of \fBNEWLINE\fR-terminated or
291 291 \fBEOF\fR-terminated variable-length records independent of the input block
292 292 boundaries. Each record is converted to a record with a fixed length specified
293 293 by the conversion block size. Any \fBNEWLINE\fR character is removed from the
294 294 input line. \fBSPACE\fR characters are appended to lines that are shorter than
295 295 their conversion block size to fill the block. Lines that are longer than the
296 296 conversion block size are truncated to the largest number of characters that
297 297 will fit into that size. The number of truncated lines is reported.
298 298 .RE
299 299
300 300 .sp
301 301 .ne 2
302 302 .na
303 303 \fB\fBunblock\fR\fR
304 304 .ad
305 305 .RS 11n
306 306 Converts fixed-length records to variable length. Reads a number of bytes equal
307 307 to the conversion block size (or the number of bytes remaining in the input, if
308 308 less than the conversion block size), delete all trailing \fBSPACE\fR
309 309 characters, and append a \fBNEWLINE\fR character.
310 310 .RE
311 311
312 312 The \fBblock\fR and \fBunblock\fR values are mutually exclusive.
313 313 .sp
314 314 .ne 2
315 315 .na
316 316 \fB\fBlcase\fR\fR
317 317 .ad
318 318 .RS 9n
319 319 Maps upper-case characters specified by the \fBLC_CTYPE\fR keyword
320 320 \fBtolower\fR to the corresponding lower-case character. Characters for which
321 321 no mapping is specified are not modified by this conversion.
322 322 .RE
323 323
324 324 .sp
325 325 .ne 2
326 326 .na
327 327 \fB\fBucase\fR\fR
328 328 .ad
329 329 .RS 9n
330 330 Maps lower-case characters specified by the \fBLC_CTYPE\fR keyword
331 331 \fBtoupper\fR to the corresponding upper-case character. Characters for which
332 332 no mapping is specified are not modified by this conversion.
333 333 .RE
334 334
335 335 The \fBlcase\fR and \fBucase\fR symbols are mutually exclusive.
336 336 .sp
337 337 .ne 2
338 338 .na
339 339 \fB\fBswab\fR\fR
340 340 .ad
341 341 .RS 11n
342 342 Swaps every pair of input bytes. If the current input record is an odd number
343 343 of bytes, the last byte in the input record is ignored.
344 344 .RE
345 345
346 346 .sp
347 347 .ne 2
348 348 .na
349 349 \fB\fBnoerror\fR\fR
350 350 .ad
351 351 .RS 11n
352 352 Does not stop processing on an input error. When an input error occurs, a
353 353 diagnostic message is written on standard error, followed by the current input
354 354 and output block counts in the same format as used at completion. If the
355 355 \fBsync\fR conversion is specified, the missing input is replaced with null
356 356 bytes and processed normally. Otherwise, the input block will be omitted from
357 357 the output.
358 358 .RE
359 359
360 360 .sp
361 361 .ne 2
362 362 .na
363 363 \fB\fBnotrunc\fR\fR
364 364 .ad
365 365 .RS 11n
366 366 Does not truncate the output file. Preserves blocks in the output file not
367 367 explicitly written by this invocation of \fBdd\fR. (See also the preceding
368 368 \fBof=\fR\fIfile\fR operand.)
369 369 .RE
370 370
371 371 .sp
372 372 .ne 2
373 373 .na
374 374 \fB\fBsync\fR\fR
375 375 .ad
376 376 .RS 11n
377 377 Pads every input block to the size of the \fBibs=\fR buffer, appending null
378 378 bytes. (If either \fBblock\fR or \fBunblock\fR is also specified, appends
379 379 \fBSPACE\fR characters, rather than null bytes.)
380 380 .RE
381 381
382 382 .RE
383 383
384 384 .sp
385 385 .ne 2
386 386 .na
387 387 \fB\fBoflag=\fR\fIvalue\fR[\fB,\fR\fIvalue\fR.\|.\|.\|]\fR
388 388 .ad
389 389 .sp .6
390 390 Where \fIvalue\fRs are comma-separated symbols from the following list which
391 391 affect the behavior of writing the output file:
392 392 .sp
393 393 .ne 2
394 394 .na
395 395 \fB\fBdsync\fR\fR
396 396 .ad
397 397 .RS 11n
398 398 The output file is opened with the \fBO_DSYNC\fR flag set. All data writes will
399 399 be synchronous. For more information on \fBO_DSYNC\fR see \fBfcntl.h\fR(3HEAD).
400 400 .RE
401 401
402 402 .sp
|
↓ open down ↓ |
402 lines elided |
↑ open up ↑ |
403 403 .ne 2
404 404 .na
405 405 \fB\fBsync\fR\fR
406 406 .ad
407 407 .RS 11n
408 408 The output file is opened with the \fBO_SYNC\fR flag set. All data and metadata
409 409 writes will be synchronous. For more information on \fBO_SYNC\fR see
410 410 \fBfcntl.h\fR(3HEAD).
411 411 .RE
412 412
413 -.RE
414 -
415 413 .sp
416 414 .LP
417 415 If operands other than \fBconv=\fR and \fBoflag=\fR are specified more than once,
418 416 the last specified \fBoperand=\fR\fIvalue\fR is used.
419 417 .sp
420 418 .LP
421 419 For the \fBbs=\fR, \fBcbs=\fR, \fBibs=\fR, and \fBobs=\fR operands, the
422 420 application must supply an expression specifying a size in bytes. The
423 421 expression, \fBexpr\fR, can be:
424 422 .RS +4
425 423 .TP
426 424 1.
427 425 a positive decimal number
428 426 .RE
429 427 .RS +4
430 428 .TP
431 429 2.
432 430 a positive decimal number followed by \fBk\fR, specifying multiplication by
433 431 1024
434 432 .RE
435 433 .RS +4
436 434 .TP
437 435 3.
438 436 a positive decimal number followed by \fBM\fR, specifying multiplication by
439 437 1024*1024
440 438 .RE
441 439 .RS +4
442 440 .TP
443 441 4.
444 442 a positive decimal number followed by \fBG\fR, specifying multiplication by
445 443 1024*1024*1024
446 444 .RE
447 445 .RS +4
448 446 .TP
449 447 5.
450 448 a positive decimal number followed by \fBT\fR, specifying multiplication by
451 449 1024*1024*1024*1024
452 450 .RE
453 451 .RS +4
454 452 .TP
455 453 6.
456 454 a positive decimal number followed by \fBP\fR, specifying multiplication by
457 455 1024*1024*1024*1024*1024
458 456 .RE
459 457 .RS +4
460 458 .TP
461 459 7.
462 460 a positive decimal number followed by \fBE\fR, specifying multiplication by
463 461 1024*1024*1024*1024*1024*1024
464 462 .RE
465 463 .RS +4
466 464 .TP
467 465 8.
468 466 a positive decimal number followed by \fBZ\fR, specifying multiplication by
469 467 1024*1024*1024*1024*1024*1024*1024
470 468 .RE
471 469 .RS +4
472 470 .TP
473 471 9.
474 472 a positive decimal number followed by \fBb\fR, specifying multiplication by
475 473 512
476 474 .RE
477 475 .RS +4
478 476 .TP
479 477 10.
480 478 two or more positive decimal numbers (with or without \fBk\fR or \fBb\fR)
481 479 separated by \fBx\fR, specifying the product of the indicated values.
482 480 .RE
483 481 .sp
484 482 .LP
485 483 All of the operands will be processed before any input is read.
486 484 .SH SIGNALS
487 485 .sp
488 486 .LP
489 487 When \fBdd\fR receives either SIGINFO or SIGUSR1, \fBdd\fR will emit the current
490 488 input and output block counts, total bytes written, total time elapsed, and the
491 489 number of bytes per second to standard error. This is the same information
492 490 format that \fBdd\fR emits when it successfully completes. Users may send
493 491 SIGINFO via their terminal. The default character is ^T, see \fBstty\fR(1) for
494 492 more information.
495 493 .sp
496 494 .LP
497 495 For \fBSIGINT\fR, \fBdd\fR writes status information to standard error before
498 496 exiting. \fBdd\fR takes the standard action for all other signals.
499 497
500 498 .SH USAGE
501 499 .sp
502 500 .LP
503 501 See \fBlargefile\fR(5) for the description of the behavior of \fBdd\fR when
504 502 encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
505 503 .SH EXAMPLES
506 504 .LP
507 505 \fBExample 1 \fRCopying from one tape drive to another
508 506 .sp
509 507 .LP
510 508 The following example copies from tape drive \fB0\fR to tape drive \fB1\fR,
511 509 using a common historical device naming convention.
512 510
513 511 .sp
514 512 .in +2
515 513 .nf
516 514 example% \fBdd if=/dev/rmt/0h of=/dev/rmt/1h\fR
517 515 .fi
518 516 .in -2
519 517 .sp
520 518
521 519 .LP
522 520 \fBExample 2 \fRStripping the first 10 bytes from standard input
523 521 .sp
524 522 .LP
525 523 The following example strips the first 10 bytes from standard input:
526 524
527 525 .sp
528 526 .in +2
529 527 .nf
530 528 example% \fBdd ibs=10 skip=1\fR
531 529 .fi
532 530 .in -2
533 531 .sp
534 532
535 533 .LP
536 534 \fBExample 3 \fRReading a tape into an ASCII file
537 535 .sp
538 536 .LP
539 537 This example reads an \fBEBCDIC\fR tape blocked ten 80-byte \fBEBCDIC\fR card
540 538 images per block into the \fBASCII\fR file \fBx\fR:
541 539
542 540 .sp
543 541 .in +2
544 542 .nf
545 543 example% \fBdd if=/dev/tape of=x ibs=800 cbs=80 conv=ascii,lcase\fR
546 544 .fi
547 545 .in -2
548 546 .sp
549 547
550 548 .LP
551 549 \fBExample 4 \fRUsing conv=sync to write to tape
552 550 .sp
553 551 .LP
554 552 The following example uses \fBconv=sync\fR when writing to a tape:
555 553
556 554 .sp
557 555 .in +2
558 556 .nf
559 557 example% \fBtar cvf - . | compress | dd obs=1024k of=/dev/rmt/0 conv=sync\fR
560 558 .fi
561 559 .in -2
562 560 .sp
563 561
564 562 .SH ENVIRONMENT VARIABLES
565 563 .sp
566 564 .LP
567 565 See \fBenviron\fR(5) for descriptions of the following environment variables
568 566 that affect the execution of \fBdd\fR: \fBLANG\fR, \fBLC_ALL\fR,
569 567 \fBLC_CTYPE\fR, \fBLC_MESSAGES\fR, and \fBNLSPATH\fR.
570 568 .SH EXIT STATUS
571 569 .sp
572 570 .LP
573 571 The following exit values are returned:
574 572 .sp
575 573 .ne 2
576 574 .na
577 575 \fB\fB0\fR\fR
578 576 .ad
579 577 .RS 6n
580 578 The input file was copied successfully.
581 579 .RE
582 580
583 581 .sp
584 582 .ne 2
585 583 .na
586 584 \fB\fB>0\fR\fR
587 585 .ad
588 586 .RS 6n
589 587 An error occurred.
590 588 .RE
591 589
592 590 .sp
593 591 .LP
594 592 If an input error is detected and the \fBnoerror\fR conversion has not been
595 593 specified, any partial output block will be written to the output file, a
596 594 diagnostic message will be written, and the copy operation will be
597 595 discontinued. If some other error is detected, a diagnostic message will be
598 596 written and the copy operation will be discontinued.
599 597 .SH ATTRIBUTES
600 598 .sp
601 599 .LP
602 600 See \fBattributes\fR(5) for descriptions of the following attributes:
603 601 .sp
604 602
605 603 .sp
606 604 .TS
607 605 box;
608 606 c | c
609 607 l | l .
610 608 ATTRIBUTE TYPE ATTRIBUTE VALUE
611 609 _
612 610 Interface Stability Standard
613 611 .TE
614 612
615 613 .SH SEE ALSO
616 614 .sp
617 615 .LP
618 616 \fBcp\fR(1), \fBsed\fR(1), \fBtr\fR(1), \fBfcntl.h\fR(3HEAD),
619 617 \fBattributes\fR(5), \fBenviron\fR(5), \fBlargefile\fR(5), \fBstandards\fR(5)
620 618 .SH DIAGNOSTICS
621 619 .sp
622 620 .ne 2
623 621 .na
624 622 \fB\fBf+p records in(out)\fR\fR
625 623 .ad
626 624 .RS 23n
627 625 numbers of full and partial blocks read(written)
628 626 .RE
629 627
630 628 .SH NOTES
631 629 .sp
632 630 .LP
633 631 Do not use \fBdd\fR to copy files between file systems having different block
634 632 sizes.
635 633 .sp
636 634 .LP
637 635 Using a blocked device to copy a file will result in extra nulls being added
638 636 to the file to pad the final block to the block boundary.
639 637 .sp
640 638 .LP
641 639 When \fBdd\fR reads from a pipe, using the \fBibs=X\fR and \fBobs=Y\fR
642 640 operands, the output will always be blocked in chunks of size Y. When
643 641 \fBbs=Z\fR is used, the output blocks will be whatever was available to be read
644 642 from the pipe at the time.
645 643 .sp
646 644 .LP
647 645 When using \fBdd\fR to copy files to a tape device, the file size must be a
648 646 multiple of the device sector size (for example, 512 Kbyte). To copy files of
649 647 arbitrary size to a tape device, use \fBtar\fR(1) or \fBcpio\fR(1).
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