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DD(1)                            User Commands                           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 statis-
              tics
       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 sug-
              gested)
       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
              discard cached data
       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 sta-
       tistics 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
       GNU  coreutils  online  help:  <http://www.gnu.org/software/coreutils/>;
       Report dd translation bugs to <http://translationproject.org/team/>;
AUTHOR
       Written by Paul Rubin, David MacKenzie, and Stuart Kemp.
COPYRIGHT
       Copyright  (C) 2013 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
       The  full  documentation  for dd is maintained as a Texinfo manual.  If
       the info and dd programs are properly installed at your site, the  com-
       mand
              info coreutils 'dd invocation'
       should give you access to the complete manual.

GNU coreutils 8.22               November 2020                           DD(1)