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dd je CLI program koji konvertira i kopira odabranu datoteku.


dd argumenti

  • bs=BYTES - read and write BYTES bytes at a time (also see ibs=,obs=)
  • cbs=BYTES - convert BYTES bytes at a time
  • conv=CONVS - convert the file as per the comma separated symbol list
  • count=BLOCKS - copy only BLOCKS input blocks
  • ibs=BYTES - read BYTES bytes at a time (default: 512)
  • if=FILE - read from FILE instead of stdin
  • iflag=FLAGS - read as per the comma separated symbol list
  • obs=BYTES - write BYTES bytes at a time (default: 512)
  • of=FILE - write to FILE instead of stdout
  • oflag=FLAGS - write as per the comma separated symbol list
  • seek=BLOCKS - skip BLOCKS obs-sized blocks at start of output
  • skip=BLOCKS - skip BLOCKS ibs-sized blocks at start of input
  • status=noxfer - suppress transfer statistics


BLOCKS and BYTES may be followed by the following multiplicative suffixes: c =1, w =2, b =512, kB =1000, K =1024, MB =1000*1000, M =1024*1024, xM =M GB=1000*1000*1000, G =1024*1024*1024, and so on for T, P, E, Z, Y.

Each CONV symbol may be:

  • ascii - from EBCDIC to ASCII
  • ebcdic - from ASCII to EBCDIC
  • ibm - from ASCII to alternate EBCDIC
  • block - pad newline-terminated records with spaces to cbs-size
  • unblock - replace trailing spaces in cbs-size records with newline
  • lcase - change upper case to lower case
  • nocreat - do not create the output file
  • excl - fail if the output file already exists
  • notrunc - do not truncate the output file
  • ucase - change lower case to upper case
  • swab - swap every pair of input bytes
  • noerror - continue after read errors
  • sync - pad every input block with NULs to ibs-size; when used with block or unblock, pad with spaces rather than NULs
  • fdatasync - physically write output file data before finishing
  • fsync - likewise, but also write metadata

Each FLAG symbol may be:

  • append append mode (makes sense only for output; conv=notrunc suggested)
  • direct use direct I/O for data
  • directory - fail unless a directory
  • dsync - use synchronized I/O for data
  • sync - likewise, but also for metadata
  • fullblock - accumulate full blocks of input (iflag only)
  • nonblock - use non-blocking I/O
  • noatime - do not update access time
  • noctty - do not assign controlling terminal from file
  • nofollow - do not follow symlinks

Sending a USR1 signal to a running ‘dd’ process makes it print I/O statistics to standard error and then resume copying.

$ dd if=/dev/zero of=/dev/null& pid=$!
$ kill -USR1 $pid; sleep 1; kill $pid
18335302+0 records in 18335302+0 records out 9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s

Options are:

--help display this help and exit
--version - output version information and exit

Autori: Paul Rubin, David MacKenzie i Stuart Kemp.

Prijava bugova:

Report dd bugs to bug-coreutils@gnu.org
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>