251 If the sync conversion is specified, the missing input
252 is replaced with null bytes and processed normally.
253 Otherwise, the input block will be omitted from the
254 output.
255
256
257 notrunc
258 Does not truncate the output file. Preserves blocks in
259 the output file not explicitly written by this
260 invocation of dd. (See also the preceding of=file
261 operand.)
262
263
264 sync
265 Pads every input block to the size of the ibs= buffer,
266 appending null bytes. (If either block or unblock is
267 also specified, appends SPACE characters, rather than
268 null bytes.)
269
270
271
272 oflag=value[,value...]
273
274 Where values are comma-separated symbols from the following list which
275 affect the behavior of writing the output file:
276
277 dsync
278 The output file is opened with the O_DSYNC flag set. All
279 data writes will be synchronous. For more information on
280 O_DSYNC see fcntl.h(3HEAD).
281
282
283 sync
284 The output file is opened with the O_SYNC flag set. All data
285 and metadata writes will be synchronous. For more
286 information on O_SYNC see fcntl.h(3HEAD).
287
288
289
290 If operands other than conv= and oflag= are specified more than once,
291 the last specified operand=value is used.
292
293
294 For the bs=, cbs=, ibs=, and obs= operands, the application must supply
295 an expression specifying a size in bytes. The expression, expr, can be:
296
297 1. a positive decimal number
298
299 2. a positive decimal number followed by k, specifying
300 multiplication by 1024
301
302 3. a positive decimal number followed by M, specifying
303 multiplication by 1024*1024
304
305 4. a positive decimal number followed by G, specifying
306 multiplication by 1024*1024*1024
307
308 5. a positive decimal number followed by T, specifying
309 multiplication by 1024*1024*1024*1024
310
311 6. a positive decimal number followed by P, specifying
312 multiplication by 1024*1024*1024*1024*1024
313
314 7. a positive decimal number followed by E, specifying
315 multiplication by 1024*1024*1024*1024*1024*1024
316
317 8. a positive decimal number followed by Z, specifying
318 multiplication by 1024*1024*1024*1024*1024*1024*1024
319
320 9. a positive decimal number followed by b, specifying
321 multiplication by 512
322
323 10. two or more positive decimal numbers (with or without k or
324 b) separated by x, specifying the product of the indicated
325 values.
326
327
328 All of the operands will be processed before any input is read.
329
330 SIGNALS
331 When dd receives either SIGINFO or SIGUSR1, dd will emit the current
332 input and output block counts, total bytes written, total time elapsed,
333 and the number of bytes per second to standard error. This is the same
334 information format that dd emits when it successfully completes. Users
335 may send SIGINFO via their terminal. The default character is ^T, see
336 stty(1) for more information.
337
338
339 For SIGINT, dd writes status information to standard error before
340 exiting. dd takes the standard action for all other signals.
341
342
343 USAGE
344 See largefile(5) for the description of the behavior of dd when
345 encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
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251 If the sync conversion is specified, the missing input
252 is replaced with null bytes and processed normally.
253 Otherwise, the input block will be omitted from the
254 output.
255
256
257 notrunc
258 Does not truncate the output file. Preserves blocks in
259 the output file not explicitly written by this
260 invocation of dd. (See also the preceding of=file
261 operand.)
262
263
264 sync
265 Pads every input block to the size of the ibs= buffer,
266 appending null bytes. (If either block or unblock is
267 also specified, appends SPACE characters, rather than
268 null bytes.)
269
270
271 oflag=value[,value...]
272
273 Where values are comma-separated symbols from the following list
274 which affect the behavior of writing the output file:
275
276 dsync
277 The output file is opened with the O_DSYNC flag set. All
278 data writes will be synchronous. For more information on
279 O_DSYNC see fcntl.h(3HEAD).
280
281
282 sync
283 The output file is opened with the O_SYNC flag set. All
284 data and metadata writes will be synchronous. For more
285 information on O_SYNC see fcntl.h(3HEAD).
286
287
288
289 If operands other than conv= and oflag= are specified more than
290 once, the last specified operand=value is used.
291
292
293 For the bs=, cbs=, ibs=, and obs= operands, the application must
294 supply an expression specifying a size in bytes. The expression,
295 expr, can be:
296
297 1. a positive decimal number
298
299 2. a positive decimal number followed by k, specifying
300 multiplication by 1024
301
302 3. a positive decimal number followed by M, specifying
303 multiplication by 1024*1024
304
305 4. a positive decimal number followed by G, specifying
306 multiplication by 1024*1024*1024
307
308 5. a positive decimal number followed by T, specifying
309 multiplication by 1024*1024*1024*1024
310
311 6. a positive decimal number followed by P, specifying
312 multiplication by 1024*1024*1024*1024*1024
313
314 7. a positive decimal number followed by E, specifying
315 multiplication by 1024*1024*1024*1024*1024*1024
316
317 8. a positive decimal number followed by Z, specifying
318 multiplication by 1024*1024*1024*1024*1024*1024*1024
319
320 9. a positive decimal number followed by b, specifying
321 multiplication by 512
322
323 10. two or more positive decimal numbers (with or without k
324 or b) separated by x, specifying the product of the
325 indicated values.
326
327
328 All of the operands will be processed before any input is read.
329
330 SIGNALS
331 When dd receives either SIGINFO or SIGUSR1, dd will emit the current
332 input and output block counts, total bytes written, total time elapsed,
333 and the number of bytes per second to standard error. This is the same
334 information format that dd emits when it successfully completes. Users
335 may send SIGINFO via their terminal. The default character is ^T, see
336 stty(1) for more information.
337
338
339 For SIGINT, dd writes status information to standard error before
340 exiting. dd takes the standard action for all other signals.
341
342
343 USAGE
344 See largefile(5) for the description of the behavior of dd when
345 encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
|