Ubuntu - How to create Image (ISO) file from CD/DVD
Here is an easy one to get started. No fancy software needed, just a couple of simple CLI commands:
(assumes that /dev/cdrom is the location of CD/DVD-ROM, if not replace as necessary)
Insert your CD/DVD and open a Terminal
sudo umount /dev/cdrom
(This unmounts the CD ready for action)
dd if=/dev/cdrom of=file.iso bs=1024
(replacing file.iso with the name you want to give)
Wait a while, the CLI will remain blank until finished, then you have your ISO