I need to extract the OS filesystem from Fedora's ISO image (downloadable from their site) using dd command?
If you already have the ISO filesystem in a file on your hard drive (downloaded from the Internet or copied, wholesale, from a CD or DVD), you'll need to mount the file in "loopback" mode. ("loopback" means the source of the filesystem is in fact another file, not a physical device.) As root, something like this would work:
# mkdir /tmp/fedora # mount /path/to/image.iso /tmp/fedora -o ro,loop -t iso9660
Then you can browse /tmp/fedora using your favorite tools.
You can use
dd to create an iso file from a CD or DVD:
# dd if=/dev/cdrom of=image.iso
dd can't do that, it just enables raw access to the ISO file itself.
I think you should use the
mount -o loop file.iso /mnt