SYNOPSIS

       dd [OPERAND]...
       dd OPTION

DESCRIPTION

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

       bs=BYTES
              force ibs=BYTES and obs=BYTES

       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

       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

       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 suf-
       fixes: xM M, c 1, w 2,  b  512,  kB  1000,  K  1024,  MB  1000*1000,  M
       1024*1024,  GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E,
       Z, Y.

       Each CONV symbol may be:
       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 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 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 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

       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 dd

       should give you access to the complete manual.



GNU coreutils 6.9                 March 2007                             DD(1)