Need help to understand the option "of=" in "dd" command

osdevkid · 03-18-2011, 02:17 AM

Dear All,

Code:

dd bs=8192 if=Image of=/dev/PS0

In the above command, I cant able to understand the option "of=/dev/PS0"

Whether it means,
1) to write the input file "Image" in to "/dev/PS0" of the FLOPPY device

or

2) to overwrite the same input file "Image" in a file format ("/dev/PS0") of FLOPPY.

Please clarify my doubt.

EricTRA · 03-18-2011, 02:25 AM

Hello,

From the man page of dd:

Code:

of=FILE
              write to FILE instead of stdout

in other words, the 'of' parameter is used to indicate where to write the output to, in your example to a device called PS0. Not sure if that's your floppy drive though. What distro are you using?

Kind regards,

Eric

catkin · 03-18-2011, 02:25 AM

It writes Image directly to whatever device is "behind" /dev/PS0. What happens next depends on the device driver and the device. In the case where /dev/PS0 is a floppy drive it writes image directly to the floppy, replacing everything on it. For that to be useful the file Image must contain whatever is needed on the floppy, including a FAT and file+directory structure+data if the floppy is to be mounted and used as a file system.