dd(1)

NAME

   dd - convert and copy a file

SYNOPSIS

   dd [OPERAND]...
   dd OPTION

DESCRIPTION

   Copy a file, converting and formatting according to the operands.

   bs=BYTES
          read and write up to BYTES bytes at a time

   cbs=BYTES
          convert BYTES bytes at a time

   conv=CONVS
          convert the file as per the comma separated symbol list

   count=N
          copy only N input blocks

   ibs=BYTES
          read up to 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=N skip N obs-sized blocks at start of output

   skip=N skip N ibs-sized blocks at start of input

   status=LEVEL
          The  LEVEL  of information to print to stderr; 'none' suppresses
          everything but error messages,  'noxfer'  suppresses  the  final
          transfer   statistics,   'progress'   shows   periodic  transfer
          statistics

   N 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

   ucase  change lower case to upper case

   sparse try to seek rather than write the output for NUL input blocks

   swab   swap every pair of input bytes

   sync   pad every input block with NULs  to  ibs-size;  when  used  with
          block or unblock, pad with spaces rather than NULs

   excl   fail if the output file already exists

   nocreat
          do not create the output file

   notrunc
          do not truncate the output file

   noerror
          continue after read errors

   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

   nocache
          Request to drop cache.  See also oflag=sync

   noctty do not assign controlling terminal from file

   nofollow
          do not follow symlinks

   count_bytes
          treat 'count=N' as a byte count (iflag only)

   skip_bytes
          treat 'skip=N' as a byte count (iflag only)

   seek_bytes
          treat 'seek=N' as a byte count (oflag only)

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

   Options are:

   --help display this help and exit

   --version
          output version information and exit

AUTHOR

   Written by Paul Rubin, David MacKenzie, and Stuart Kemp.

REPORTING BUGS

   GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
   Report dd translation bugs to <http://translationproject.org/team/>

COPYRIGHT

   Copyright    2016  Free Software Foundation, Inc.  License GPLv3+: GNU
   GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
   This is free software: you are free  to  change  and  redistribute  it.
   There is NO WARRANTY, to the extent permitted by law.

SEE ALSO

   Full documentation at: <http://www.gnu.org/software/coreutils/dd>
   or available locally via: info '(coreutils) dd invocation'

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Free and Open Source Software