how to create iso image from DVD [duplicate]

Insert the CD or DVD that you want to make an ISO image of, and open a terminal window. To do that, just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command(s) below:

sudo cat /dev/srx > /home/<user_name>/<file_name.iso>

Make sure that you replace (x) with your device number.

for example in my case I would do:

sudo cat /dev/sr0 > /home/mitch/example.iso

In Brasero Disk Burner which is installed on Ubuntu by default, select Disc Copy and select Disk image for Select a Disk to write to and create image.

Either use Brasero, like Mohammad Etemaddar suggested, or dd, as described here: http://www.wikihow.com/Create-an-ISO-File-in-Linux

The method which is described in WikiHow: dd if=/dev/cdrom of=~/cdrom_image.iso

if: input file

of: output file

dd: disk dump

Another very good description on making ISO image has been written here.