man/cat1/dd.1.txt

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
              force ibs=BYTES and obs=BYTES
 
       cbs=BYTES
              convert BYTES bytes at a time
 
       conv=CONVS
              convert the file as per the comma separated sym-
              bol 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 multi-
       plicative suffixes: 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:
 
       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)
 
       direct use direct I/O for data
 
       dsync use synchronized I/O for data
 
       sync likewise, but also for metadata
 
       nonblock
              use non-blocking I/O
 
       nofollow
              do not follow symlinks
 
       noctty do not assign controlling terminal from file
 
       Sending a SIGUSR1 signal to a running `dd' process makes
       it print I/O statistics to standard error, then to
       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 sec-
              onds, 271 MB/s
 
       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
       Report bugs to <bug-coreutils@gnu.org>.
 
COPYRIGHT
       Copyright (C) 2004 Free Software Foundation, Inc.
       This is free software; see the source for copying condi-
       tions. There is NO warranty; not even for MERCHANTABIL-
       ITY or FITNESS FOR A PARTICULAR PURPOSE.
 
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 command
 
              info dd
 
       should give you access to the complete manual.
 
 
 
dd (coreutils) 5.3.0 November 2004 DD(1)