Mac OS Terminal: dd command

Discussion in 'Mac Basics and Help' started by ACiB708, Jun 19, 2009.

  1. macrumors regular

    Apr 6, 2008
    Hey all just wanted to know what I'm doing wrong.

    In linux if I want to dump the contents of a CD/DVD onto a path I type:

    sudo dd if=/dev/cdrom of=/root/user1/desktop/cdrom.iso (or whatever path)

    Linux does it's thing and after a while I get the file I wanted. Since Mac OS is also UNIX-based and this is a UNIX command, I'd expect it to be the same. So I type:

    sudo dd if=/Volumes/cdname of=/Users/username/Desktop/cd.iso

    but when I hit enter instead of doing something, it instantly shows me this:

    0+1 records in
    0+1 records out
    136 bytes transferred in 3.596678 secs (38 bytes/sec)

    And it gives a 4KB file, or sometimes an empty file. What am I doing wrong?
    Thanks for any help in advance!
  2. macrumors 68020


    Apr 12, 2006
    Long Island
  3. thread starter macrumors regular

    Apr 6, 2008

    Oh, so it was because in Darwin you have to unmount the volume first... and also not copying the image from the /Volumes dir but instead form the device itself?? Thanks a lot it helped.

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