Name
dd — convert and copy a file
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 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;
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
- 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.
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>.
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
should give you access to the complete manual.
| COPYRIGHT |
|
Copyright © 2007 Free Software Foundation,
Inc.
This is free software. You may redistribute
copies of it under the terms of the GNU General
Public License
<http://www.gnu.org/licenses/gpl.html>. There
is NO WARRANTY, to the extent permitted by law.
|
