Powerful "dd" command.

- Aniketh Girish


It has been long since I have been writing. The thing is that I was busy with some project. To be more specifically, I'm an open source guy and I contribute to KDE. I was working for a project called KStars as my KDE Season of Code project. And Yeah! It's finished with my part. The mentor needs to review it. I will be posting another post regarding this. Sharing my experiences and everything.

So today I'm writing on one of my some favorite command in our terminal. The command is the dd command.

The dd commands general use is like convert and copy a file.

The basic function of dd command what I like about is that we could create a bootable disk image without any software, from just one line of code. Yeah! you heard it right, just one line.

First thing what you will have to do is that Insert the pen drive.

Secondly, Open a terminal and type in the following command.

~$ sudo dd if=nameoftheiso.iso of=/dev/sdb

This line just makes you pen drive bootable.  That's it. Wait for a while till the iso is made bootable and you are ready to go.


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 a 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 a 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 the 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.

Description source from the man page. ;)

From now onwards I will try to be regular at posting different cool stuff into my blog. :D